AERIAL COMMUNICATIONS INC
8-K, 1998-06-16
RADIOTELEPHONE COMMUNICATIONS
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                                    FORM 8-K

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       The Securities Exchange Act of 1934

         Date of Report (Date of earliest event reported): June 1, 1998
                                                           ------------ 

                           Aerial Communications, Inc.
                           ---------------------------
             (Exact name of registrant as specified in its charter)


     Delaware                      0-28262                  39-1706857
     --------                      -------                  ----------
   (State or other               (Commission              (IRS Employer
    jurisdiction of              File Number)            Identification No.)
    incorporation)

                                    
                                                               
                                 
                                  
  8410 West Bryn Mawr, Suite 1100, Chicago, Illinois             60631
 ----------------------------------------------------           -------
         (Address of principal executive offices)              (Zip Code)

Registrant's telephone number, including area code:  (773) 399-4200


                                 Not Applicable
                                 --------------
          (Former name or former address, if changed since last report)








<PAGE>




Item 5.   Other Events.
          -------------
                     Agreement for Sale of Subsidiary Equity

                  On June 1, 1998, Aerial Communications,  Inc. (the "Company"),
APT Operating Company,  Inc., a wholly-owned  subsidiary of the Company ("AOC"),
Telephone and Data Systems, Inc., the parent corporation of the Company ("TDS"),
and Sonera Corporation,  a limited liability company organized under the laws of
Finland and formerly known as Telecom  Finland Ltd.  ("Sonera"),  entered into a
Purchase Agreement (the "Purchase Agreement") pursuant to which Sonera agreed to
purchase  from AOC  2,410,482  shares  of  common  stock of AOC (the  "Purchased
Shares")  for an  aggregate  purchase  price  of $200  million,  resulting  in a
purchase  price of  approximately  $82.971 per common  share of AOC ("AOC Common
Shares") and representing a 19.423% equity interest in AOC. Sonera will have the
right under certain  circumstances  (described below) to exchange each AOC Share
for  6.72919  Common  Shares of Aerial  ("Aerial  Common  Shares"),  subject  to
adjustment.  Upon the exchange of all of the Purchased Shares,  Sonera would own
an  18.452%  equity  interest  in  the  Company  (reflecting  a  purchase  price
equivalent to $12.33 per Aerial Common Share). If TDS has distributed  shares of
TDS common equity intended to separately reflect the performance of the personal
communications  service ("PCS") business of Aerial and its subsidiaries ("Aerial
Group  Shares"),  then each AOC Share would be exchanged  for a number of Aerial
Group Shares (initially  6.24341,  subject to adjustment)  representing the same
percentage interest in the PCS business.

                  The  closing of the  purchase  of the  Purchased  Shares  (the
"Closing") is subject to the satisfaction of certain  conditions,  including (I)
obtaining  from  the  Federal  Communications  Commission  ("FCC")  a  favorable
declaratory  ruling  granting  permission  to the  Company  and  its  subsidiary
licensees to exceed the 25% statutory  benchmark for indirect foreign  ownership
under the  Communications  Act of 1934, as amended,  and (ii) the  expiration or
early termination of all applicable waiting periods under the  Hart-Scott-Rodino
Antitrust Improvements Act of 1976, as amended.

                  The number of Purchased Shares is subject to adjustment if the
Aerial  Average (as defined  herein) for any 20  consecutive  trading day period
during the first  three  years after the date of Closing  (the  "Closing  Date")
exceeds certain threshold prices, as follows:

                                                 Resulting    Equivalent
             Aerial           Purchased Shares   % Equity     Resulting %
Threshold    Equivalent       Subject To         Interest     Equity Interest
Price        Share Price      Cancellation       in AOC       in the Company
- ---------    -----------      ----------------   ---------    ----------------

$ 9.50       $13.78           256,375            17.723%      16.837%
 10.50        15.23           207,082            16.297       15.482
 11.50        16.68           170,759            15.083       14.329


The Aerial  Average  refers to the daily means of the high and low sales  prices
for Aerial  Common  Shares or,  subject to  adjustment  to reflect the  issuance
thereof, Aerial Group Shares.

                  On the Closing  Date,  the  Company,  AOC, TDS and Sonera will
enter into an  Investment  Agreement  which will  provide,  inter alia,  for the
following:


                                        2

<PAGE>



         ( i) Appointment of Directors.  The Company will increase the number of
 members of its Board of Directors to at least 12 and add two directors 
designated by Sonera to such Board.

         (ii) Subscription Rights for AOC Common Shares. Each of the Company and
Sonera will have  subscription  rights,  exercisable upon the issuance by AOC of
AOC Common  Shares or certain  convertible  securities,  permitting  each of the
Company and Sonera to purchase that  proportion  of each such issuance  equal to
the   proportion   of  AOC  Common  Shares  owned  by  the  Company  or  Sonera,
respectively, immediately prior to such issuance.

         (iii)  Option to Acquire  Additional  AOC Common  Shares.  Prior to the
tenth  anniversary of the Closing Date,  Sonera will have the option to purchase
additional AOC Common Shares to increase its percentage  equity  interest in AOC
to 20% at various prices (subject to certain minimum prices)  implying a premium
of at least 30% of the 20-day  Aerial  Average at the time of  exercise  of such
option,  except that there will be no premium to the extent  that such  purchase
either  (A) is in lieu of the  purchase  by Sonera of New Issue  Securities  (as
defined  herein)  or (B)  results  from the  conversion  by  Sonera of New Issue
Securities  purchased  and so  converted  during the first three years after the
Closing Date.

         (iv)  Subscription  Rights for  Aerial  Common  Shares or Aerial  Group
Shares.  Prior to the tenth  anniversary  of the Closing Date,  Sonera will have
subscription  rights,  exercisable upon (A) the issuance for cash by the Company
of Aerial Common Shares (subject to certain  exceptions) or certain  convertible
securities,  to  purchase  100% of such  Aerial  Common  Shares  or  convertible
securities,  subject to the  subscription  rights of TDS with respect thereto or
(B) the  issuance  for cash by TDS of Aerial  Group  Shares  (subject to certain
exceptions) or certain convertible securities,  to purchase 17.5% of such Aerial
Group Shares or  convertible  securities  (such Aerial  Common  Shares or Aerial
Group Shares, as applicable, and convertible securities being referred to as the
"New Issue  Securities"),  such subscription  rights being subject to an overall
limitation on Sonera's maximum percentage equity interest of approximately 33%.

         (v) Restrictions on Transfer of AOC Common Shares.  Except with respect
to transfers to permitted  affiliate  transferees  and in certain  other limited
circumstances, Sonera will be prohibited from transferring AOC Common Shares (A)
prior to the fifth  anniversary  of the Closing  Date without the consent of TDS
and the Company and (B) after the fifth  anniversary of the Closing Date without
first engaging in good faith  negotiations  with the Company for the transfer of
the AOC Common Shares to the Company.

         (vi) Equity Exchanges. (A) Prior to the fifth anniversary of the 
Closing Date, Sonera will not have the right to exchange the AOC Common Shares 
owned by Sonera except in the event of (1) a change of control of TDS, (2) a 
going private transaction involving TDS or (3) a sale of all or substantially 
all of the assets of AOC and its subsidiaries.

                  (B) At any time  after the ninth  anniversary  of the  Closing
Date,  Sonera will have the right to require the Company to purchase  all of the
AOC Common Shares owned by Sonera in exchange for, at the Company's option,  (1)
Aerial Common Shares (or, if distributed,  Aerial Group Shares),  (2) TDS Common
Shares  (or,  if  distributed,  Aerial  Group  Shares),  (3)  cash  or  (4)  any
combination of the foregoing.  Sonera will have the right to exercise such right
in cumulative  20%  increments  during the 30 days  following each of the fifth,
sixth, seventh and eighth anniversaries of the Closing Date.


                                        3

<PAGE>



                  (C) At any time  after the tenth  anniversary  of the  Closing
Date, Sonera will have the right to exchange AOC Common Shares for Aerial Common
Shares (or, if distributed, Aerial Group Shares).

         (vii) Issuance of Derivative  Security.  After the fifth anniversary of
the  Closing  Date (or  prior  to such  fifth  anniversary  in  certain  limited
circumstances) and prior to the tenth anniversary thereof,  Sonera will have the
right to issue a derivative security which becomes  exchangeable after the tenth
anniversary  for AOC Common Shares owned by Sonera.  At any time after the tenth
anniversary  of the Closing Date,  the Company will have the right to repurchase
all of such AOC Common  Shares in exchange  for, at the  Company's  option,  (A)
Aerial Common Shares (or, if distributed,  Aerial Group Shares),  (B) TDS Common
Shares  (or,  if  distributed,  Aerial  Group  Shares),  ( C)  cash  or (D)  any
combination of the foregoing.

         (viii)  Restrictions  on  Acquisition of Aerial Common Shares or Aerial
Group Shares. Prior to the tenth anniversary of the Closing Date, Sonera will be
prohibited from acquiring any Aerial Common Shares or Aerial Group Shares except
as set forth above.

         (ix)  Restrictions  on Certain  Disposition  Transactions.  TDS and the
Company  will  be  prohibited  from  entering  into  certain  transactions  (not
including certain spin-off or similar transactions) resulting in the disposition
of the Company or AOC,  respectively,  without first  engaging in exclusive good
faith negotiations with Sonera regarding such disposition  transaction,  subject
to certain  tag-along rights of Sonera and certain  drag-along rights of TDS and
the Company.

         (xi) Certain  Transactions  Involving  Sonera. In the event that Sonera
enters into a transaction providing for a reorganization,  merger, consolidation
or other combination,  or for the disposition of all or substantially all of the
assets of Sonera, and such transaction  involves a material competitor of TDS or
the Company,  then TDS and the Company will have the right to require  Sonera to
use its reasonable best efforts to negotiate a transfer of all of the AOC Common
Shares to a person reasonably acceptable to TDS and the Company.

Certain of the foregoing  rights are subject to termination  upon the occurrence
of  certain  events,  such as the  failure  of Sonera to  maintain  a  specified
percentage  equity  interest,  the transfer by Sonera of AOC Common Shares,  the
issuance by Sonera of a derivative  security,  the failure of Sonera to exercise
its subscription rights or the passage of time.

                  On the Closing Date, the existing  Revolving  Credit Agreement
between the Company and TDS will be terminated and a new credit agreement,  with
substantially  the same  terms,  between  AOC and TDS will be  substituted.  The
Company will guarantee  AOC's  obligations  under the new credit  agreement.  In
addition,  AOC will  become a party to the  existing  Tax  Allocation  Agreement
between TDS and the Company.

                  On the Closing Date,  the Company and Sonera will enter into a
Registration  Rights  Agreement  which will  provide  Sonera  with three  demand
registrations  and five  piggyback  registrations  with respect to Aerial Common
Shares or Aerial Group Shares,  as applicable,  during the period  commencing on
the fifth  anniversary  of the Closing  Date and  terminating  on the  twentieth
anniversary  of the Closing Date (subject to earlier  termination  under certain
circumstances).


                                        4

<PAGE>



                  On the  Closing  Date,  the  Company,  AOC,  Sonera and Sonera
Corporation  U.S., a wholly-owned  subsidiary of Sonera  ("Sonera  U.S."),  will
enter into a Joint Venture  Agreement which,  subject to certain  exceptions and
limitations  set forth  therein,  will serve during the  Exclusivity  Period (as
defined  herein) as the  exclusive  vehicle  through  which the parties will (I)
acquire licenses issued by the FCC to provide broadband PCS in the United States
and (ii) build and  operate  systems  with  respect to such  licenses  utilizing
Global  Systems For Mobile  Communications  Technology,  subject to such changes
resulting from the evolution of such technology or the development of subsequent
technologies based thereon or derived therefrom. It is contemplated by the Joint
Venture  Agreement  that  AOC and  Sonera  U.S.  will  form a  separate  limited
liability company (each an "LLC"),  which may include additional  investors,  to
operate  each market in which a broadband  PCS license is acquired  and that AOC
(or an  affiliate  thereof)  will  manage the system  with  respect to each such
broadband  PCS license so acquired.  In  consideration  of  performance  of such
management  services  with  respect to each LLC,  AOC will receive a 15% carried
interest  in such  LLC,  which  carried  interest  will be  subject  to  partial
divestiture  under certain  circumstances  during the first five years after the
formation of such LLC. The Exclusivity  Period will commence on the Closing Date
and  terminate  on the  earlier  to occur of (A) the  fifth  anniversary  of the
Closing Date or (B) the date upon which Sonera U.S. has invested an aggregate of
$400  million in the  equity of one or more LLCs  formed  pursuant  to the Joint
Venture Agreement.

         This  Current  Report  on Form 8-K is being  filed for the  purpose  of
filing the Aerial news  release  dated June 2, 1998 and the  Purchase  Agreement
dated  June  1,  1998,   between  Telephone  and  Data  Systems,   Inc.,  Aerial
Communications, Inc., APT Operating Company, Inc.
and Sonera Corporation.


Item 7.           Financial Statements and Exhibits
                  ---------------------------------
( c)     Exhibits
         --------
         The exhibits  accompanying  this report are listed in the  accompanying
Exhibit Index.


                                        5

<PAGE>





                                 SIGNATURES


         Pursuant to the  requirements  of the Securities  Exchange Act of 1934,
the  registrant  has duly  caused  this report to be signed on its behalf by the
undersigned, thereto duly authorized.


Date:    June  16, 1998            AERIAL COMMUNICATIONS, INC.
                                   (Registrant)





                                    By: /s/ J. Clarke  Smith
                                       -------------------------------------
                                    J. Clarke Smith
                                    Vice President - Finance and Administration,
                                    Chief Financial Officer and Treasurer












                                        6

<PAGE>




                                  EXHIBIT INDEX


Exhibit Number            Description of Exhibit
- --------------            ----------------------

    99.1                  Aerial news release dated June 2, 1998.

    99.2                  The Purchase Agreement between Telephone and Data 
                          Systems, Inc. Aerial Communications, Inc., APT 
                          Operating Co., Inc. and Sonera Corporation dated June 
                          1, 1998.























                                        7

<PAGE>




                                                                    EXHIBIT 99.1

NEWS RELEASE
                                                                        Contact:
                                                                 J. Clarke Smith
                                                                  (773) 399 4200
                                                     Aerial Communications, Inc.

                                                               Kaj-Erik Relander
                                                                  +358 2040 5365
                                                              Sonera Corporation

FOR RELEASE: IMMEDIATE

                  SONERA CORPORATION, FORMERLY TELECOM FINLAND,
                 TO INVEST $200 MILLION IN AERIAL COMMUNICATIONS

June 2, 1998  Chicago, Illinois - Sonera Corporation (formerly Telecom Finland 
Ltd), one of Europe's leading wireless telecommunications operators, will take 
a $200-million equity stake in a wholly-owned subsidiary of Aerial  
Communications, Inc. [NASDAQ:AERL].  Aerial is a leading U.S. Personal  
Communications Services (PCS) provider.  Sonera's investment will be its first  
in a U.S. wireless operator, and will make the Finnish company Aerial's largest 
independence investor.

Sonera and Aerial have signed a definitive purchase agreement for Sonera to make
a $200 million investment in Aerial Operating Company, a wholly-owned subsidiary
of Aerial.  The price per share and equity  ownership  percentage for Sonera are
subject to adjustment  based on Aerial's  20-day  average stock price during the
three years after the Closing Date. Depending on the stock price, the price will
range from a low of $12.33 per equivalent Aerial share for an equivalent 18.452%
equity ownership,  to a high of $16.68 per equivalent Aerial share for a 14.329%
equivalent  equity ownership.  In addition,  after five years Sonera's equity in
Aerial   Operating   Company   becomes   exchangeable   for   equity  of  Aerial
Communications,  Inc. or, in certain  circumstances,  exchangeable for equity in
Telephone and Data Systems, Inc. or cash.

As  part  of the  agreement,  the  two  companies  also  will  form a  strategic
partnership  to work together in areas such as new product  development,  and to
jointly explore new business opportunities in the U.S. PCS market. The agreement
is subject to regulatory approval.

Bringing additional experience and innovation to Aerial
"We are  excited  to form this  relationship  with  Sonera,  one of the  world's
foremost wireless  telecommunications  companies," said Don Warkentin,  Aerial's
President and Chief Executive Officer. "We anticipate that this partnership will
benefit Aerial in many ways beyond Sonera's substantial investment.  Sonera will
also provide considerable  experience and expertise to enhance our business and,
in turn, improve shareholder value.

"Sonera is one of the leading wireless  operators in the world." Warkentin said.
"In fact,  they are the world  leader  in  market  penetration.  Over 30% of the
Finnish  population  were Sonera  wireless  customers  at the end of 1997.  This
represents a 74% market share in a country with a total penetration of over 42%.
By contrast,  the total wireless industry  penetration in the U.S. at the end of
1997 was 22%.


                                        8

<PAGE>



"Sonera has demonstrated a commitment to research and  development.  In 1997, it
devoted more than 3% of its total sales and revenue to R&D in emerging  areas as
the internet,  data and multimedia  services," Warkentin said. "Sonera currently
offers  wireless  internet  service  and  is  developing  "intelligent  network"
platforms for a variety of new services.  We anticipate that the new partnership
will help to bring similar capabilities to Aerial markets.

"We believe Sonera is living the future of wireless  communications,"  Warkentin
continued.  "Many of Sonera's  customers are using their wireless phone as their
primary phone,  switching telephone usage from a wireline phone to an affordable
wireless alternative.  In Finland, Sonera is already billing more minutes on its
wireless  networks than its public wireline  networks.  Aerial can learn a great
deal from Sonera's  experience  and  innovation."  Aerial plans to tap into this
reservoir of expertise in several  ways,  according to  Warkentin.  For example,
Sonera personnel will join Aerial's staff in key strategic positions, especially
in the area of new product development. Two Sonera executives also will join the
Aerial Board of Directors.

"With  this  transaction,  we will have  secured  the final  piece of  financing
originally planned by Aerial," Warkentin said. "Equally important, the agreement
is a  far-reaching  alliance  and  working  partnership  between  two  prominent
wireless communications companies."

Expanding beyond Sonera's traditional borders
"We  are  pleased  to  partner  with  such  an   innovative   leader  as  Aerial
Communications," said Kaj-Erik Relander, Executive Vice President of Sonera. "We
see our  commitments  to the U.S.  market as a very important part of our global
strategy to continue to expand our business beyond our traditional borders.

Sonera's   growing   international   operations   include   seven   wholly-owned
subsidiaries as well as strategic  investments in more than 20 companies  around
the world. In addition, Sonera has a record of successful experience in wireless
joint ventures in markets like Turkey, Russia and the Middle East.

"Aerial is an excellent choice as our U.S. partner," Relander said.  "Both 
companies use and understand the potential of GSM (Global System for Mobile 
communications) technology.  Also, in adding 200,000 customers in its first 
full year of operations, Aerial has demonstrated that it can build its 
business quickly. Its stress on fairness and value for the customer demonstrate
an innovative and differentiated approach to the market.  Aerial's True Per-
Second Billingsm, for example, is unique in the American market."

Sonera  Corporation is Finland's leading  telecommunications  company,  based in
Helsinki.  The company has  numerous  subsidiaries  and  affiliate  companies in
several  different  countries.  It is  currently  state-owned,  but the  Finnish
government  has  announced  plans for a partial  privatization  of the  company.
Sonera offers a full line of telecommunications  services and products,  and had
sales of U.S. $1.4 billion in 1997.

Aerial Communications, headquartered in Chicago, holds licenses to provide PCS 
service in areas covering 27.6 million of the U.S. population.  Aerial's markets
include Columbus, Ohio; Houston, Minneapolis, Kansas City, Pittsburgh and 
Tampa/Orlando/St. Petersburg. Aerial is a majority-owned subsidiary of Telephone
and Data Systems, Inc., a $1.5 billion telecommunications company based
in Chicago.

                                        9

<PAGE>



Except  for  historical  and  factual   information   contained  herein,   other
information   set  forth  in  this  news  release   represents   forward-looking
statements,  including  all  statements  about  the  Company's  plans,  beliefs,
estimates and expectations.  These statements are based on current estimates and
projections,  which  involve  certain risks and  uncertainties  that could cause
actual  results  to  differ   materially  from  those  in  the   forward-looking
statements.  Important factors that may affect these forward-looking  statements
include, but are not limited to: changes in Delaware law; potential  litigation;
and changes in market conditions. Investors are encouraged to consider these and
other risks and  uncertainties  which are  discussed in  documents  filed by the
Company with the Securities and Exchange Commission.

                                      ####

Aerial and True Per-Second Billing are service marks of Aerial Communications, 
Inc.






























                                       10



<PAGE>



                                                                    EXHIBIT 99.2



                                                                  EXECUTION COPY









                               PURCHASE AGREEMENT

                                      AMONG

                        TELEPHONE AND DATA SYSTEMS, INC.,

                             a Delaware Corporation,

                          AERIAL COMMUNICATIONS, INC.,

                             a Delaware Corporation,

                          APT OPERATING COMPANY, INC.,

                             a Delaware Corporation,

                                       AND

                               SONERA CORPORATION

                       a Finnish Limited Liability Company



                              dated: June __, 1998






<PAGE>


                                TABLE OF CONTENTS
                                -----------------

ARTICLE 1...............................................................3

         DEFINITIONS....................................................3



ARTICLE 2...............................................................10

         PURCHASE OF STOCK; CLOSING.....................................10

                  2.1      Purchase of Common Stock.....................10
                           ------------------------ 
                  2.2      Closing......................................10
                           ------- 
                  2.3   Purchase Price Adjustment.......................11
                        -------------------------
                  2.4   Effect of Aerial Merger or Distribution.........14
                        ---------------------------------------

ARTICLE 3...............................................................15

         COVENANTS AND AGREEMENTS.......................................15

                  3.1      Covenants of TDS and the Aerial Parties......15
                           ---------------------------------------
                  3.2      Covenants of the Investor....................19
                           -------------------------
                  3.3      Governmental Filings.........................20
                           --------------------

ARTICLE 4...............................................................22

         REPRESENTATIONS AND WARRANTIES.................................22

                  4.1      Representations and Warranties of the 
                           -------------------------------------
                           Aerial Parties ..............................22
                           --------------
                  4.2      Representations and Warranties of 
                           --------------------------------- 
                           the Investor ................................30
                           ------------ 
                  4.3      Representations and Warranties of TDS........34
                           -------------------------------------

ARTICLE 5...............................................................38

         CONDITIONS TO OBLIGATIONS......................................38

                  5.1      Conditions to the Obligation of TDS and 
                           ---------------------------------------
                           the Aerial Parties  .........................38
                           ------------------
                  5.2      Conditions to the Obligation of the Investor
                           --------------------------------------------
                            ............................................40


ARTICLE 6...............................................................43

         SURVIVAL ......................................................43

                  6.1      Survival of Representations and Warranties.  43
                           ------------------------------------------
                  6.2      Indemnity by TDS and the Aerial Parties......43
                           ---------------------------------------
                  6.3      Indemnity by the Investor....................45
                           -------------------------
                  6.4      Procedure....................................46
                           ---------
                  6.5      Indemnity Sole Remedy........................47
                           ---------------------

ARTICLE 7...............................................................48

         MISCELLANEOUS..................................................48

                  7.1      Expenses.....................................48
                           --------
                  7.2      Equitable Remedies...........................48
                           ------------------ 
                  7.3      Notices......................................48
                           -------
                  7.4      Entire Agreement.............................51
                           ----------------

                                       ii

<PAGE>



                  7.5      Remedies Cumulative..........................52
                           -------------------
                  7.6      Governing Law................................52
                           -------------  
                  7.7      Counterparts.................................52
                           ------------ 
                  7.8      Waivers......................................52
                           -------
                  7.9      Successors and Assigns.......................52
                           ----------------------
                  7.10     Further Assurances...........................53
                           ------------------
                  7.11     Disclosures..................................53
                           -----------
                  7.12     Termination..................................54
                           -----------
                  7.13     No Claim of Immunity.........................56
                           --------------------
                  7.14     Severability.................................56
                           ------------ 

ARTICLE 8...............................................................57

         DISPUTES ......................................................57

                  8.1      General......................................57
                           -------
                  8.2      Negotiation Procedure........................57
                           ---------------------
                  8.3      Unresolved Disputes..........................58
                           -------------------
                  8.4      Jurisdiction; Consent to Service of Process..58
                           ------------------------------------------- 















                                       iii

<PAGE>



                               PURCHASE AGREEMENT



                  This  PURCHASE  AGREEMENT,  is made as of June __,  1998  (the
"Agreement"),  by and  among  TELEPHONE  AND  DATA  SYSTEMS,  INC.,  a  Delaware
corporation  ("TDS"),  AERIAL  COMMUNICATIONS,   INC.,  a  Delaware  corporation
("Aerial"),  APT OPERATING COMPANY,  INC., a Delaware corporation (the "Company"
and, together with Aerial,  the "Aerial  Parties"),  and SONERA  CORPORATION,  a
limited  liability  company  organized under the laws of the Republic of Finland
(the "Investor").

                                R E C I T A L S :

                  WHEREAS, TDS is the owner of more than 80% of the outstanding
capital stock of Aerial;

                  WHEREAS, Aerial is the owner of all of the outstanding capital
stock of the Company;

                  WHEREAS, the Company is engaged in the business of providing
broadband personal communications services in the United States;


                  WHEREAS,   the   Investor  is  engaged   directly  or  through
Affiliates in the communications business in, among other places, Finland;

                  WHEREAS,  Aerial  and  the  Investor,   acting  through  their
respective  subsidiaries,  desire to form a joint  venture  for the  purpose  of
investing in and  operating  systems in the United  States  providing  broadband
personal  communications services using Global Systems for Mobile Communications
technology;

                  WHEREAS,  in addition to forming the joint  venture,  upon the
terms and conditions set forth in this Agreement,  the Company has determined to
issue and sell,  and the Investor has  determined  to purchase,  an aggregate of
2,410,482  shares of the Company's common stock, par value $0.001 per share (the
"Common Stock"),  which upon issuance will constitute  19.423% of the issued and
outstanding Common Stock of the Company;


<PAGE>



                  WHEREAS, Telephone and Data Systems, Inc., an Iowa corporation
and  TDS's  immediate  predecessor  ("TDS  Iowa"),  and one of its  wholly-owned
Subsidiaries,  filed with the Securities and Exchange  Commission a Registration
Statement  on Form S-4, and  Amendments  No. 1 and 2 thereto,  which  included a
Proxy Statement and Prospectus (the "TDS Proxy Statement"),  copies of which, as
amended and supplemented, were furnished to the Investor;



                  WHEREAS,  the  shareholders  of TDS Iowa approved the proposal
(the "Tracking Stock Proposal") described in the TDS Proxy Statement dated March
24, 1998, as amended by a Proxy Statement Supplement dated April 20, 1998;

                  WHEREAS, effective May 22, 1998, TDS Iowa was merged with and
into TDS;

                  WHEREAS,  immediately  prior  to the  effective  time  of such
merger,  the  Certificate  of  Incorporation  of TDS was amended and restated to
among  other  things,  authorize  a new  class of common  stock of TDS  Delaware
("Aerial Group Shares")  intended to separately  reflect the  performance of the
personal  communications  service  business  of  Aerial  and  its  Subsidiaries,
including all assets and liabilities allocated thereto (the "Aerial Group"); and

                  WHEREAS, (i) TDS Iowa has offered to issue Aerial Group Shares
in  exchange  for all  outstanding  Aerial  Common  Shares  pursuant to a merger
between  Aerial and a  wholly-owned  subsidiary  of TDS, and (ii) TDS intends to
make a  distribution  of Aerial Group Shares,  in the form of a stock  dividend,
with respect to each outstanding Common and Series A Common Share of TDS;

                  NOW,  THEREFORE,  in  consideration  of the  premises  and the
mutual  covenants,  conditions and promises  hereinafter set forth,  the parties
hereby agree as follows:



                                       -2-

<PAGE>


                                    ARTICLE 1

                                   DEFINITIONS


                  Unless  the  context  otherwise  requires,  the terms  defined
hereunder  shall have the meanings  therein  specified  for all purposes of this
Agreement,  applicable to both the singular and plural forms of any of the terms
defined herein. For purposes of this Agreement:

                  "Additional  Agreements" shall mean the Investment  Agreement,
the Joint Venture Agreement and the Registration Rights Agreement to be executed
at the Closing.

                  "Aerial" shall have the meaning set forth in the preamble
hereof.

                  "Aerial Acquisition Proposal" shall have the meaning set forth
in Section 3.1(i) hereof.

                  "Aerial  Adjustment Event" shall have the meaning set forth in
Section 2.3(b) hereof.

                  "Aerial  Average"  shall mean (i) for any period of  reference
prior to the  earlier to occur of the  Aerial  Merger or the  Distribution,  the
average of the daily  means of the high and low sales  prices for Aerial  Common
Shares, as reported in the applicable composite transactions section or national
market  issues  section of The Wall Street  Journal , and (ii) for any period of
reference  thereafter,  the average of the daily means of the high and low sales
prices  for  Aerial  Group  Shares,  as  reported  in the  applicable  composite
transactions  section or  national  market  issues  section  of The Wall  Street
Journal.

                  "Aerial  Benefit  Plans"  shall have the  meaning set forth in
Section 4.1(l) hereof.

                  "Aerial  Common  Shares"  shall  mean the  class of  shares of
Aerial  designated as Common Shares in its Certificate of  Incorporation,  as in
effect on the Closing Date.

                  "Aerial  Common Stock" shall mean Aerial Common Shares and the
class  of  shares  of  Aerial  designated  as  Series  A  Common  Shares  in its
Certificate of Incorporation, as in effect on the Closing Date.

                  "Aerial Group" shall have the meaning set forth in the
preamble hereof.

                  "Aerial Group Shares" shall have the meaning set forth in the
preamble hereof.

                                       -3-

<PAGE>



                  "Aerial  Merger" shall mean the  acquisition  by TDS of all of
the Aerial  Common Shares that it does not own,  pursuant to (i) a  transaction,
including  the  Aerial  Merger  (as  that  term  is  defined  in the  TDS  Proxy
Statement),  in which Aerial Group Shares are issued and immediately after which
Aerial Group Shares are listed on a national  securities  exchange or authorized
for quotation on NASDAQ or (ii) any other  transaction  upon the consummation of
which Aerial  becomes a  wholly-owned  subsidiary  of TDS and TDS has issued and
outstanding  Aerial  Group  Shares  that are  listed  on a  national  securities
exchange or authorized for quotation on NASDAQ.

                  "Aerial Parties" shall have the meaning set forth in the 
preamble hereof.

                  "Aerial  Shares"  shall  mean (i) with  respect to any time of
reference prior to the earlier of (A) the date of the Aerial Merger,  or (B) the
date of the  Distribution,  Aerial Common  Shares,  and (ii) with respect to any
time of reference thereafter, Aerial Group Shares.

                  "Affiliate" shall mean, with respect to any party hereto,  any
corporation or other  business  entity which,  directly or  indirectly,  through
stock ownership or through any other arrangement,  controls, is controlled by or
is under common  control with,  such party.  The term  "control"  shall mean the
possession, direct or indirect, of the power to direct or cause the direction of
the  management  or policies of such  person,  whether by reason of ownership of
voting stock or other equity interests, by contract or otherwise.

                  "Agreement" shall have the meaning set forth in the preamble
hereof.


                  "Amended  Tax  Allocation   Agreement"   shall  mean  the  Tax
Allocation  Agreement,  as amended  as of the  Closing  Date,  by and among TDS,
Aerial and the Company.

                  "Anniversary"  shall mean the date  occurring  12 months after
the Closing Date and the date occurring each 12 months thereafter.

                                       -4-

<PAGE>



                  "AOC  Revolving  Credit  Agreement"  shall mean the  Revolving
Credit  Agreement,  dated as of the  Closing  Date,  by and  between TDS and the
Company.

                  "Authorization"    shall   mean   any   franchise,    license,
authorization,  consent, permit, waiver, approval, qualification or registration
of, with or from the FCC, any state public utility or public service commission,
or  any  other  governmental   authority,   agency  or  instrumentality   having
jurisdiction over the relevant party and matter.

                  "Business  Day"  shall  mean any day  other  than a  Saturday,
Sunday,  legal holiday in Chicago,  Illinois,  or other day on which  commercial
banks in Chicago are authorized by law or governmental decree to close.

                  "Closing" shall have the meaning set forth in Section 2.2
hereof.

                  "Closing Date" shall have the meaning set forth in Section 2.2
hereof.

                  "Code" shall mean the Internal Revenue Code of 1986, as 
amended.

                  "Common Stock" shall have the meaning set forth in the
preamble hereof.

                  "Communications  Act"  shall  mean the  Communications  Act of
1934,  and  any  similar  or  successor  federal  statute,  and  the  rules  and
regulations  of the FCC  thereunder,  all as  amended  and as the same may be in
effect from time to time.

                  "Company" shall have the meaning set forth in the preamble
hereof.

                  "Disclosures" shall have the meaning set forth in Section 7.11
(a) hereof.

                  "Distribution"  shall mean the  distribution  by TDS of Aerial
Group Shares, in the form of a stock dividend,  with respect to each outstanding
Common and Series A Common Share of TDS.

                  "Dollar"  or "$"  shall  mean  the  basic  unit of the  lawful
currency of the United States of America.



                                       -5-

<PAGE>



                  "ERISA" shall have the meaning set forth in Section 4.1(l)
hereof.

                  "Exchange Rate" shall have the meaning provided for it in the
Investment Agreement.

                  "Exchange Rate  Applicable to Aerial Common Shares" shall have
the meaning provided it in the Investment Agreement.

                  "Exchange  Rate  Applicable to Aerial Group Shares" shall have
the meaning provided it in the Investment Agreement.

                  "Favorable  Declaratory  Ruling"  shall have the  meaning  set
forth in Section 3.3(a) hereof.

                  "FCC"  shall mean the  United  States  Federal  Communications
Commission,  or any other similar or successor agency of the federal  government
administering the Communications Act.

                  "Final  Order"  shall mean an action or  decision as to which:
(i) no request for a stay is pending, no stay is in effect, and any deadline for
filing such request that may be designated by statute or regulation  has passed;
(ii) no petition for rehearing or  reconsideration  or application for review is
pending  and the time for filing any such  petition or  application  has passed;
(iii) the FCC,  public  utility  commission  or public  service  commission  (or
comparable bodies exercising jurisdiction over the Company or its communications
businesses)  does not have the action or decision under  reconsideration  on its
own motion and the time for initiating such reconsideration has passed; and (iv)
no appeal is pending or in effect and any  deadline  for filing any such  appeal
that may be designated by statute or rule has passed.

                  "HSR  Act"   shall   mean  the   Hart-Scott-Rodino   Antitrust
Improvements Act of 1976, as amended.

                  "Indemnification Period" shall mean the period ending on the
second Anniversary.

                                       -6-

<PAGE>



                  "Indemnitee"  shall mean that  party  which has  sustained  or
incurred Losses and is seeking indemnification pursuant to Article 6 hereof.

                  "Indemnitor"   shall  mean  that  party  which  is   providing
indemnification pursuant to Article 6 hereof.

                  "Investment Agreement" shall mean the agreement  substantially
in the form attached as EXHIBIT 1.1 hereto.

                  "Investor" shall have the meaning set forth in the preamble
hereof.

                  "Joint   Venture   Agreement"   shall   mean   the   agreement
substantially in the form attached as EXHIBIT 1.2 hereto.


                  "Lien" shall mean any lien, claim, security interest,  charge,
encumbrance or title retention agreement of any nature.

                  "Losses" shall have the meaning set forth in Section 6.2(a)
hereof.

                  "Material Adverse Effect" shall mean a material adverse effect
on  the  financial   condition,   operations  or  business  of  Aerial  and  its
Subsidiaries,  taken as a whole, or on the ability of TDS, Aerial or the Company
to enter into and  consummate  the  transactions  contemplated  by, and lawfully
perform their obligations under, this Agreement and the Additional Agreements in
accordance with their respective terms.

                 "NASDAQ" shall mean National Association of Securities Dealers,
Inc. Automated Quotation System.

                  "Number  of  Aerial  Group  Shares"  shall  have  the  meaning
provided for it in the Investment Agreement.

                  "Operating  Financial  Statements"  shall have the meaning set
forth in Section 4.1(g) hereof.

                                       -7-

<PAGE>



                  "PCS  Authorization"  shall  mean  any FCC  Authorization  for
providing  broadband  PCS  mobile  communications  services  through  the use of
microcells with low-power  transmitters,  each serving a small area operating in
the 1850-1910 MHz and the 1930-1990 MHz bands.

                  "Permitted Affiliate Transferees" shall have the meaning
provided it in the Investment Agreement.

                  "Person"  shall  mean  any  general  or  limited  partnership,
corporation,  limited liability company,  joint venture,  trust, business trust,
governmental agency, cooperative,  association,  individual or other entity, and
heirs, executors, administrators, legal representatives,  successors and assigns
of such person.

                  "Purchase Price" shall have the meaning set forth in Section
2.1 hereof.

                  "Purchased Shares" shall have the meaning set forth in Section
2.1 hereof.

                  "Registration  Rights  Agreement"  shall  mean  the  agreement
substantially in the form attached as EXHIBIT 1.3 hereto.

                  "Securities  Act" shall mean the  Securities  Act of 1933, and
any  similar  or  successor  federal  statute,  and the  rules  and  regulations
promulgated  thereunder,  all as amended,  and as the same may be in effect from
time to time.

                  "Sonera Parties" shall mean the Investor and Sonera U.S.

                  "Sonera U.S." shall mean Sonera  Corporation  U.S., a Delaware
corporation and wholly-owned subsidiary of the Investor and a party to the Joint
Venture Agreement.

                  "Subsidiary"  of a Person shall mean a corporation as to which
a majority of the voting power is owned or  controlled  by such  Person,  either
directly  or  indirectly;  but any  such  corporation  shall be  deemed  to be a
Subsidiary of such Person only as long as such ownership or control exists.

                  "Taxes"  shall  mean  all  taxes,  charges,  levies  or  other
assessments  of any kind,  including  income,  gross  receipts,  sales,  use, ad
valorem, franchise, profits, license, withholding,  payroll, employment, excise,
severance,  stamp,  occupation,  premium,  property or windfall  profits  taxes,
customs duties or similar fees,  assessments or charges of any kind  whatsoever,
together with any interest and penalties, additions to tax or additional amounts
imposed by any taxing authority,

                                       -8-

<PAGE>



domestic  or  foreign  and  any  expenses   incurred  in  connection   with  the
determination,  settlement  or  litigation  of  any  liability  for  any  of the
foregoing.

                  "Tax Return" shall mean a report,  return or other information
required to be supplied to a taxing authority with respect to Taxes.

                  "TDS" shall have the meaning set forth in the preamble hereof.

                  "TDS  Adjustment  Event"  shall have the  meaning set forth in
Section 2.3(d) hereof.

                  "TDS Iowa" shall have the meaning set forth in the preamble
hereof.

                  "TDS Parties" shall mean TDS, Aerial and the Company.

                  "Threshold Prices" shall have the meaning set forth in Section
2.3(b) hereof.

                  "Tracking Stock Proposal" shall have the meaning set forth in
the preamble hereof.

                  "20-Day  Aerial  Average"  shall have the meaning set forth in
Section 2.3(a) hereof.

                  When a reference is made in this Agreement to a Section,  such
reference shall be to a Section of this Agreement  unless  otherwise  indicated.
Whenever  the  words  "include,"  "includes"  or  "including"  are  used in this
Agreement,   they  shall  be  deemed  to  be  followed  by  the  words  "without
limitation."  The use of a gender  herein shall be deemed to include the neuter,
masculine and feminine genders whenever  necessary or appropriate.  Whenever the
word "herein" or "hereof" is

                                       -9-

<PAGE>



used in this Agreement, it shall be deemed to refer to this Agreement and not to
a particular Section of this Agreement unless expressly stated otherwise.

                                    ARTICLE 2

                           PURCHASE OF STOCK; CLOSING

                  2.1 Purchase of Common Stock.  The Investor hereby  subscribes
for and agrees to purchase from the Company,  and the Company hereby accepts the
Investor's subscription for and agrees to sell to the Investor,  2,410,482 newly
issued,  fully paid and  non-assessable  shares of Common Stock (the  "Purchased
Shares") for a purchase price of approximately  Eighty-Two Dollars  Ninety-Seven
and  One-Tenth  Cents  ($82.971)  per share,  which shall result in an aggregate
purchase price of $200,000,000  (the "Purchase  Price") and represent 19.423% of
the Company's outstanding capital stock (on a fully diluted basis).

                  2.2   Closing.   (a)  Closing   Date.   Consummation   of  the
transactions  contemplated  hereby (the "Closing") shall take place,  subject to
the  satisfaction  (or express  written waiver) of all conditions to the Closing
under  Article 5 hereof,  on the tenth  Business Day after the later to occur of
(i) the day on which all FCC and state regulatory  approvals,  if any, including
the Favorable Declaratory Ruling,  necessary in order to consummate lawfully the
transactions  contemplated hereby have been received and shall have become Final
Orders,  or (ii) the day on which all applicable  waiting  periods under the HSR
Act shall have expired or been terminated without objection by the Federal Trade
Commission.  The date on which the  Closing  takes  place  shall be  referred to
herein as the "Closing Date."

                                      -10-

<PAGE>



                  (b)  Location.  The Closing  shall take place at 10:00 A.M. on
the  Closing  Date,  at the  offices  of  Sidley & Austin  located  at One First
National  Plaza,  Suite 5500,  Chicago,  IL 60603, or at such other place as the
parties  hereto shall agree to in writing.  At the Closing,  the Company  shall,
upon receipt of the Purchase  Price by wire  transfer of  immediately  available
funds to an account  designated by the Company at least five Business Days prior
to the Closing Date,  promptly  deliver to the Investor duly executed and issued
stock certificates evidencing the Purchased Shares.

                  2.3  Purchase  Price  Adjustment.  (a) In the  event  that the
Aerial  Average for any 20  consecutive  trading day period (the "20-day  Aerial
Average") from the Closing through the third  Anniversary  exceeds $9.50,  then,
within ten Business Days after the Investor's receipt of a notice from Aerial of
such  20-day  Aerial  Average,  the  Investor  shall  deliver to the Company for
cancellation  256,375  Purchased  Shares.  In the event that the  20-day  Aerial
Average from the Closing through the third  Anniversary  exceeds  $10.50,  then,
within ten Business Days after the Investor's receipt of a notice from Aerial of
such  20-day  Aerial  Average,  the  Investor  shall  deliver to the Company for
cancellation  207,082 additional  Purchased Shares. In the event that the 20-day
Aerial Average from the Closing  through the third  Anniversary  exceeds $11.50,
then,  within ten Business  Days after the  Investor's  receipt of a notice from
Aerial of such 20-day Aerial Average,  the Investor shall deliver to the Company
for cancellation 170,759 additional Purchased Shares.


                  (b) In the event  that,  at any time after the date hereof and
prior to the earlier of the Aerial  Merger and the  Distribution,  Aerial  shall
effect  any  transaction,  including  (i)  the  payment  of a  dividend  on  the
outstanding  Aerial Common Shares in the form of Aerial  Common  Shares,  (ii) a
subdivision of the outstanding Aerial Common Shares into a larger number of such
Aerial Common

                                      -11-

<PAGE>



Shares,  (iii) a  combination  of the  outstanding  Aerial  Common Shares into a
smaller  number of such Aerial  Common  Shares,  or (iv) any  reorganization  or
reclassification  of the Aerial Common Shares,  or any  consolidation  or merger
with another corporation,  or the sale of all or substantially all of its assets
to another corporation, in such a way that the holders of the outstanding Aerial
Common Shares shall be entitled to receive  (either  directly or upon subsequent
liquidation) stock, securities, or other property with respect to or in exchange
for such Aerial Common Shares (any such  transaction  or event being referred to
as an "Aerial  Adjustment  Event"),  then the 20-day  average prices at or above
which the  Investor  shall  present  shares  for  cancellation  (the  "Threshold
Prices"),  as  provided  in  Section  2.3(a)  hereof,  shall be  proportionately
adjusted to reflect such Aerial Adjustment Event. In the event that Aerial shall
effect an Aerial Adjustment Event at any time after the date hereof and prior to
the earlier of (A) Aerial Merger, (B) the Distribution,  and (C) the delivery of
the Purchased Shares on the Closing Date, then the Exchange Rate provided for in
the  Investment  Agreement  shall be  proportionately  adjusted to reflect  such
Aerial Adjustment Event.


                  (c) In the event  that the Aerial  Merger or the  Distribution
shall occur at any time after the date hereof and prior to the third Anniversary
then,  upon the earlier of such events to occur,  the Threshold  Prices provided
for in Section 2.3(a) hereof shall be adjusted as set forth below:

                           (i)      In the event that the Aerial Merger occurs
prior to the  Distribution,  each of the  Threshold  Prices shall be adjusted by
dividing such Threshold Price by a fraction, the numerator of which shall be the
Number of Aerial Group Shares,  determined  immediately after the Aerial Merger,
and the  denominator  of which  shall be the  total  number  of shares of Aerial
Common Stock outstanding immediately prior to the Aerial Merger; and

                                      -12-

<PAGE>



                           (ii)     In the event that the Distribution shall
occur prior to the Aerial  Merger,  (A) each of the  Threshold  Prices  shall be
adjusted by dividing such Threshold Price by a fraction,  the numerator of which
shall be the quotient  obtained by dividing the Number of Aerial Group Shares by
TDS's  percentage  ownership of Aerial  Common  Stock,  in each case  determined
immediately after the Distribution,  and the denominator of which  shall be the
total number of shares of Aerial Common Stock  outstanding  immediately prior to
such Distribution,  and (B) in the event that the Aerial Merger shall thereafter
occur,  the  Threshold  Prices  shall be adjusted  by dividing  such prices by a
fraction,  the  numerator of which shall be the Number of Aerial  Group  Shares,
determined  immediately  after the Aerial Merger,  and the  denominator of which
shall be the quotient  obtained by dividing the Number of Aerial Group Shares by
TDS's  percentage  ownership of Aerial  Common  Stock,  determined  in each case
immediately before the Aerial Merger.

                  (d)  In  the  event  that  either  the  Aerial  Merger  or the
Distribution  shall occur at any time after the date hereof  then,  in the event
that TDS shall thereafter effect any transaction, including (i) the payment of a
dividend on the  outstanding  Aerial  Group  Shares in the form of Aerial  Group
Shares,  (ii) a subdivision of the outstanding Aerial Group Shares into a larger
number of such Aerial  Group  Shares,  (iii) a  combination  of the  outstanding
Aerial Group Shares into a smaller  number of such Aerial Group Shares,  or (iv)
any reorganization or  reclassification  of the Aerial Group Shares, or the sale
of all or  substantially  all of the  assets  of the  Aerial  Group  to  another
corporation,  in such a way that the  holders of Aerial  Group  Shares  shall be
entitled to receive  (either  directly or upon  subsequent  liquidation)  stock,
securities  or other  property  with  respect to or in exchange  for such Aerial
Group  Shares  (any  such  transaction  or  event  being  referred  to as a "TDS
Adjustment  Event"),  the Threshold  Prices referred to in Section 2.4(a) hereof
shall be  proportionately  adjusted to reflect such TDS Adjustment Event. In the
event that either the Aerial Merger or the Distribution  shall occur at any time
after the date hereof and prior to the delivery of the  Purchased  Shares on the
Closing

                                      -13-

<PAGE>



Date then, in the event that TDS shall thereafter  effect a TDS Adjustment Event
at any time prior to the Closing  Date,  the Exchange  Rate  provided for in the
Investment  Agreement  shall be  proportionately  adjusted  to reflect  such TDS
Adjustment Event.

                  2.4 Effect of Aerial  Merger or  Distribution.  In addition to
any adjustment otherwise required by Section 2.3 hereof:

                  (a) in the event that the  Aerial  Merger  shall  occur at any
time after the date of this Agreement and prior to both the Distribution and the
delivery of the  Purchased  Shares on the Closing  Date,  then the Exchange Rate
Applicable to Aerial  Common  Shares set forth in Section 7.2 of the  Investment
Agreement shall be adjusted (to determine the Exchange Rate Applicable to Aerial
Group  Shares,  referred to in the  Investment  Agreement) by  multiplying  such
exchange  rate by a  fraction,  the  numerator  of which  shall be the Number of
Aerial Group Shares,  determined  immediately  after the Aerial Merger,  and the
denominator  of which shall be the total number of shares of Aerial Common Stock
outstanding immediately prior to the Aerial Merger; and

                  (b) in the event that the Distribution shall occur at any time
after the date of this  Agreement  and prior to both the  Aerial  Merger and the
delivery of the Purchased Shares on the Closing Date, then:

                           (i)   the  Exchange  Rate  Applicable  to  Aerial
Common  Shares set forth in Section  7.2 of the  Investment  Agreement  shall be
adjusted (to  determine  the Exchange  Rate  Applicable  to Aerial Group Shares,
referred to in the Investment Agreement) by multiplying such

                                      -14-

<PAGE>



exchange  rate by a  fraction,  the  numerator  of which  shall be the  quotient
obtained  by  dividing  the Number of Aerial  Group  Shares by TDS's  percentage
ownership of Aerial Common Stock, in each case determined  immediately after the
Distribution,  and the  denominator of which shall be the total number of shares
of Aerial Common Stock outstanding immediately prior to such Distribution; and

                           (ii)     in the event that the Aerial Merger shall
thereafter  occur, the Exchange Rate Applicable to Aerial Group Shares in effect
immediately  prior  to the  date of such  merger  shall  be  adjusted  so  that,
immediately after such merger, the quotient obtained by dividing (A) the product
of the aggregate  number of shares of Common Stock owned by the Investor and its
Permitted  Affiliate  Transferees  (as  defined  in the  Investment  Agreement),
determined  immediately after such merger,  multiplied by such exchange rate, as
adjusted  pursuant  to  this  Section  2.4(b)(ii)(B),  by (B) the sum of (I) the
Number of Aerial Group Shares,  determined  immediately  after such merger,  and
(II) the  product  referred  to in (A)  above,  shall  be equal to the  quotient
obtained by dividing (1) the product of the aggregate number of shares of Common
Stock owned by the Investor and its Permitted Affiliate Transferees,  multiplied
by the Exchange Rate Applicable to Aerial Group Shares,  in each case determined
immediately  before such merger,  by (2) the sum of (x) the quotient obtained by
dividing  the Number of Aerial  Group  Shares by TDS's  percentage  ownership of
Aerial Common Stock  (determined  immediately  before such merger),  and (y) the
product referred to in (1) above.

                                    ARTICLE 3

                            COVENANTS AND AGREEMENTS

                  3.1      Covenants of TDS and the Aerial Parties.  (a)
Consummate Transactions. From and after the execution and delivery of this
Agreement to and including the Closing Date, TDS

                                      -15-

<PAGE>



and the Aerial  Parties  shall use their  reasonable  best  efforts to cause the
transactions contemplated by this Agreement to be consummated in accordance with
the terms hereof,  including (i) using their  reasonable  best efforts to obtain
all  Authorizations  of, and make all filings  with and give all notices to, all
governmental  authorities and agencies having jurisdiction,  including,  without
limitation,  the FCC (including the Favorable Declaratory Ruling), and any state
public utilities or public service  commission,  and (ii) using their reasonable
best efforts to obtain all  Authorizations  of, and making all filings with, and
giving all notices to, third parties, which in any such case may be necessary or
reasonably  required  of TDS or  either  of  the  Aerial  Parties  in  order  to
consummate the transactions  contemplated hereby.  Aerial hereby irrevocably and
unconditionally   agrees  to  cause  the  Company  to  perform  its  obligations
(including  causing or enabling the Company to issue the Purchased Shares to the
Investor) hereunder.

                  (b) Access.  From and after the execution and delivery of this
Agreement to and including the Closing  Date,  TDS and the Aerial  Parties shall
give  to  the  Investor  and  its  agents  and  representatives  (including  its
independent auditors and attorneys) all reasonably requested access (such access
not to interfere  unreasonably  with TDS, the Aerial Parties or their respective
operations),  during  normal  business  hours  and  upon  reasonable  notice  as
described  below,  to  all  of  the  personnel,  premises,  properties,  assets,
financial statements and records, books, contracts, documents and commitments of
TDS,  Aerial  and  Aerial's  Subsidiaries,  in each  case of or  relating  to or
affecting  Aerial and its  Subsidiaries,  and shall furnish the Investor and its
agents  and  representatives  with  all  such  information  and  copies  thereof
concerning  the  affairs  of  or  relating  to  or  affecting   Aerial  and  its
Subsidiaries, as the Investor may reasonably request.

                  (c)  Ordinary Course.  From  and  after  the  execution and
delivery of this Agreement to and including the Closing Date, Aerial and the
Company will, and Aerial and the Company will

                                      -16-

<PAGE>



cause  Aerial's  Subsidiaries  to,  conduct their  respective  businesses in the
ordinary and normal course thereof.

                  (d)  Compliance  with Law.  From and after the  execution  and
delivery of this  Agreement to and including the Closing Date,  TDS,  Aerial and
the Company shall, and Aerial and the Company shall cause Aerial's  Subsidiaries
to, comply with all applicable  laws,  rules,  ordinances,  regulations,  codes,
orders,  decrees,  licenses  and  permits of all  applicable  jurisdictions  and
governmental authorities or agencies relating to Aerial and its Subsidiaries, to
the  properties  of  Aerial  and  its  Subsidiaries  or to  the  conduct  of the
businesses  of Aerial  and its  Subsidiaries,  except to the extent a failure to
comply would not have a Material  Adverse Effect or a material adverse effect on
any PCS Authorization.

                  (e)  Approvals,  Consents.  From and after the  execution  and
delivery of this  Agreement to and including the Closing Date,  TDS,  Aerial and
the Company shall, and Aerial and the Company shall cause Aerial's  Subsidiaries
to, obtain and maintain in full force and effect all Authorizations necessary or
required for the operation of the businesses of Aerial and its  Subsidiaries  as
presently  conducted,  except,  in the  case of  Authorizations  other  than PCS
Authorizations, where such failure would not have a Material Adverse Effect.

                  (f) No Amendments.  Except as otherwise contemplated hereby or
by the Investment  Agreement,  from and after the execution and delivery of this
Agreement to and including the Closing Date,  none of TDS, Aerial or the Company
shall,  nor shall Aerial or the Company permit any of Aerial's  Subsidiaries to,
amend its respective Certificate of Incorporation or By-laws or any Intercompany
Agreement, in any way to alter or change the rights of the Investor (i) provided
in this Agreement,  the Additional Agreements or any Intercompany  Agreement, or
(ii) provided by such

                                      -17-

<PAGE>



Certificate  of  Incorporation  or  By-laws,  in either case so as to affect the
Investor  adversely.  On or prior to the Closing Date, the Company shall file an
amendment to its  Certificate  of  Incorporation  in the form of EXHIBIT  3.1(f)
annexed hereto.

                  (g)  Books and  Records.  From and  after  the  execution  and
delivery of this  Agreement to and including the Closing Date,  TDS,  Aerial and
the Company shall, and Aerial and the Company shall cause Aerial's  Subsidiaries
to,  maintain its books,  accounts and records in the usual  manner,  on a basis
consistent with prior years and in accordance with generally accepted accounting
principles.

                  (h) Certain Actions. From and after the execution and delivery
of this Agreement to and including the Closing Date,  none of TDS, Aerial or the
Company  shall,  nor  shall  Aerial  or  the  Company  permit  any  of  Aerial's
Subsidiaries  to,  take any action  which  would  materially  interfere  with or
preclude  the  consummation  of  the   transactions   contemplated  by,  or  the
performance  of  their  respective  obligations  under,  this  Agreement  or any
Additional Agreement, result in any of the representations and warranties of any
party hereto  contained  herein being  incorrect or  incomplete  in any material
respect,  or result in any of the conditions to the  obligations of the Investor
to consummate the  transactions  contemplated  by this Agreement as set forth in
Section 5.2 hereof being unsatisfied in accordance with the terms hereof.

                  (i) No  Solicitation,  Etc.  From the date hereof  through the
Closing or the earlier termination of this Agreement, none of TDS, Aerial or the
Company  or any  of  Aerial's  Subsidiaries  or  Affiliates,  nor  any of  their
respective officers, directors, employees, agents or representatives (including,
without  limitation,  investment  bankers,  attorneys  and  accountants)  shall,
directly or  indirectly,  (i) solicit  any merger,  consolidation,  liquidation,
dissolution or exclusive licensing

                                      -18-

<PAGE>



arrangement or similar  transaction  involving  Aerial or its  Subsidiaries  (an
"Aerial Acquisition Proposal"), or (ii) enter into substantive negotiations with
any third party in response to an Aerial  Acquisition  Proposal unless the Board
of Directors of Aerial determines in good faith that it is in the best interests
of  Aerial's  stockholders  to engage in such  substantive  negotiations  (after
considering  the  benefits to Aerial of the  transactions  contemplated  by this
Agreement  and the Joint  Venture  Agreement  and the  potential  impact of such
negotiations on such  Agreements).  Aerial shall promptly notify the Investor if
any  discussions  or  negotiations  are sought to be  initiated,  any inquiry or
proposal is made,  or any  information  is requested  with respect to any Aerial
Acquisition  Proposal and notify the Investor of the terms of any proposal which
it may receive in respect of any such Aerial  Acquisition  Proposal,  including,
without  limitation,  the identity of the  prospective  purchaser or  soliciting
party,  except  to the  extent  that any such  notification  would  violate  any
agreement of Aerial or the Company.

                  (j) Tax Filings.  From and after the execution and delivery of
this Agreement to and including the Closing Date, the Company shall, and TDS and
Aerial shall cause all members of Aerial's  consolidated  group to,  timely file
all federal, state and local Tax Returns and all information returns and reports
required  to be filed by or with  respect  to it  under  the laws of the  United
States  or any  state or other  jurisdiction  and pay as and when due all  Taxes
payable thereunder.


                  3.2  Covenants of the Investor.
                       -------------------------     

                  (a)  Consummate Transactions.  The Investor covenants and
agrees from and after the execution and delivery of this Agreement to and
including the Closing Date that it shall use its

                                      -19-

<PAGE>



reasonable  best  efforts,  and cause  Sonera  U.S. to use its  reasonable  best
efforts,  to  cause  the  transactions  contemplated  by  this  Agreement  to be
consummated  in  accordance  with the  terms  hereof,  including  (i)  using its
reasonable  best efforts to obtain all  Authorizations  of, and make all filings
with and give all notices to, all governmental authorities and agencies,  having
jurisdiction,  including,  without limitation,  the FCC (including the Favorable
Declaratory   Ruling),   and  any  state  public  utilities  or  public  service
commission,   and  (ii)  using  its  reasonable   best  efforts  to  obtain  all
Authorizations of, and making all filings with, and giving all notices to, third
parties,  which in any such case may be necessary or reasonably  required of the
Investor  in order to  consummate  the  transactions  contemplated  hereby.  The
Investor hereby irrevocably and  unconditionally  agrees to cause Sonera U.S. to
execute and deliver the Joint  Venture  Agreement  on the Closing Date if all of
the  provisions of Section 5.2 hereof are satisfied or waived on or prior to the
Closing Date.

         (b) Certain Actions.  From and after the execution and delivery of this
Agreement to and  including the Closing  Date,  the Investor  shall not take any
action which would materially interfere with or preclude the consummation of the
transactions  contemplated  by,  or  the  performance  of  the  Sonera  Parties'
respective  obligations  under, this Agreement or any Additional  Agreement,  as
applicable,  result in any of the  representations  and  warranties of any party
hereto contained  herein being incorrect or incomplete in any material  respect,
or result in any of the  conditions  to the  obligations  of TDS and the  Aerial
Parties to consummate  the  transactions  contemplated  by this Agreement as set
forth in Section  5.1 hereof  being  unsatisfied  in  accordance  with the terms
hereof.

                  3.3 Governmental Filings. Each of the parties hereto covenants
and agrees from and after the  execution  and delivery of this  Agreement to and
including the Closing Date as follows:

                                      -20-

<PAGE>



                  (a)   Regulatory   Agencies.   It  is   understood   that  the
consummation  of  this  transaction  is  subject  to  obtaining  from  the FCC a
Favorable Declaratory Ruling (as defined below), which has become a Final Order,
and may be subject to the prior approval pursuant to Final Orders of one or more
state regulatory  commissions.  As soon as practicable following the date hereof
and in no event later than ten Business  Days from the date hereof,  the parties
shall use their  reasonable best efforts to file with (i) the FCC a petition for
a  declaratory  ruling  seeking FCC  approval  under  Section  310(b)(4)  of the
Communications  Act to permit indirect foreign investment in the Aerial Group as
contemplated  by this  Agreement,  including the purchase by the Investor of the
Purchased  Shares (the "Favorable  Declaratory  Ruling"),  and (ii) any relevant
regulatory  agency(ies) a joint  application(s)  requesting the approval of such
agency(ies) to the transactions  contemplated hereby. Each of the parties hereto
shall  diligently  take or  cooperate  in the  taking  of all  steps  which  are
necessary or appropriate to expedite the prosecution and favorable consideration
of such  applications.  The parties  covenant  and agree to  undertake  all such
actions and to file all such material as may be reasonably  requested by the FCC
or other regulatory authority and to obtain any necessary Authorization from the
FCC  or  such  state  agency  or  agencies  in  connection  with  the  foregoing
applications.

                  (b) HSR Act. It is understood  that the  consummation  of this
transaction  is subject to the filing with the Federal Trade  Commission and the
Antitrust Division of the Department of Justice of all reports and notifications
which  are  required  under the HSR Act and the  expiration  or  termination  of
certain  applicable  waiting periods under the HSR Act without objection by such
authorities.  Within ten  Business  Days of the date of  execution  hereof,  the
parties  hereto  shall  file,  or cause to be  filed,  with  the  Federal  Trade
Commission  and the Antitrust  Division of the Department of Justice any and all
such reports or notifications and any other filings required under any other

                                      -21-

<PAGE>



federal law or administrative regulations in connection with the purchase of the
Purchased Shares under this Agreement.

                                    ARTICLE 4

                         REPRESENTATIONS AND WARRANTIES

                  4.1 Representations and Warranties of the Aerial Parties. Each
of the Aerial  Parties  represents and warrants,  jointly and severally,  to the
Investor,  which  representations and warranties shall survive the execution and
delivery of this Agreement and the consummation of the transactions contemplated
hereby, as follows:

                  (a) Due Organization.  Aerial is a corporation duly organized,
validly  existing and in good standing  under the laws of the State of Delaware.
Aerial  is  duly  qualified  to do  business  and  is in  good  standing  in all
jurisdictions  where  the  conduct  of  its  business  or the  ownership  of its
properties makes such  qualification  necessary,  except where the failure to so
qualify would not have a Material Adverse Effect.

                  (b) Power and Authority;  No Violation.  Each Aerial Party has
full power and authority to execute,  deliver and perform its obligations  under
this Agreement and the Additional  Agreements and to consummate the transactions
contemplated  hereby or thereby,  except  that the Company  shall be required to
amend its Certificate of  Incorporation  pursuant to Section 3.1(f) hereof prior
to  the  Closing  Date.  This  Agreement,  the  Additional  Agreements  and  all
transactions   contemplated  hereby  or  thereby  have  been  duly  and  validly
authorized  by all  necessary  action on the part of each of the Aerial  Parties
and, assuming the due authorization and execution of this

                                      -22-

<PAGE>



Agreement by the Investor, this Agreement constitutes a legal, valid and binding
obligation  of  each  of the  Aerial  Parties,  as  applicable,  enforceable  in
accordance  with its  terms,  except as such  enforceability  may be  limited by
bankruptcy,  insolvency,  reorganization,   moratorium  or  other  similar  laws
affecting or relating to enforcement of creditors' rights  generally.  Except as
described on EXHIBIT 4.1(b) annexed hereto,  neither the execution,  delivery or
performance  of  this  Agreement  or,  upon  their  execution,   the  Additional
Agreements,  nor the  consummation of the  transactions  contemplated  hereby or
thereby by the Aerial Parties will,  with or without the giving of notice or the
passage of time,  or both,  (i)  conflict  with,  violate,  result in a default,
breach or loss of rights (or give rise to any right of termination, cancellation
or acceleration)  under, or result in the creation of any Lien,  pursuant to (A)
any provision of the Certificate of Incorporation, By-laws, or other constituent
documents of either Aerial Party or any of their  respective  Subsidiaries;  (B)
any  material  note,  bond,  indenture,   mortgage,  deed  of  trust,  contract,
agreement, lease or other instrument or obligation to which either Aerial or any
of its  Subsidiaries is a party or by which Aerial or any of its Subsidiaries or
their  respective  property  may be bound or  affected;  or (C) any law,  order,
judgment,  ordinance,  rule,  regulation or decree to which Aerial or any of its
Subsidiaries is a party or by which they or their  respective  property is bound
or affected;  or (ii) give rise to any right of first  refusal or similar  right
with respect to any interest,  or any properties or assets,  of Aerial or any of
its  Subsidiaries.  Except as described on EXHIBIT  4.1(b)  annexed  hereto,  no
permit, consent, approval,  authorization,  qualification or registration of, or
declaration  to or filing with,  any  governmental  or  regulatory  authority or
agency or any third party is required to be obtained or made by Aerial or any of
its  Subsidiaries  in  connection  with  the  execution  and  delivery  of,  and
performance by Aerial or the Company of their respective obligations under, this
Agreement,  the  Additional  Agreements,  or the  consummation  by Aerial or the
Company of the transactions  contemplated  hereby or thereby, in order to render
this  Agreement,  the Additional  Agreements and the  transactions  contemplated
hereby or thereby valid and effective.

                                      -23-

<PAGE>


                  (c)  Legal  Matters.  Except as set  forth on  EXHIBIT  4.1(c)
annexed  hereto,   there  is  no  claim,  legal  action,   counterclaim,   suit,
arbitration,  governmental  investigation or other legal,  administrative or tax
proceeding,  or any order, decree or judgment, in progress or pending, or to the
knowledge of the Aerial Parties threatened,  against or relating to the right of
either  Aerial  Party to execute and deliver this  Agreement  or the  Additional
Agreements or perform its  obligations  under this  Agreement or any  Additional
Agreement,  or which could  reasonably  be  expected to have a Material  Adverse
Effect,  nor does either  Aerial Party know of any basis for the same.  There is
outstanding  no order,  writ,  injunction,  judgment  or  decree  of any  court,
governmental  agency or arbitration  tribunal which would individually or in the
aggregate  have a Material  Adverse  Effect or otherwise  impair in any material
respect the  performance of the  obligations of either Aerial Party hereunder or
under  the  Additional  Agreements,  or the  consummation  of  the  transactions
contemplated hereby or thereby.

                  (d)  Truth and Correctness.  No representation  or warranty by
either Aerial Party in this  Agreement or any Additional  Agreement  contains or
will contain any untrue  statement  of a material  fact or omits or will omit to
state a material  fact  necessary  to make the  statements  contained  herein or
therein, in light of the circumstances under which such statements are made, not
misleading.

                  (e)  Purchased  Shares.  The  Purchased  Shares  will,  at the
Closing, be duly authorized by all necessary corporate action on the part of the
Company,  will be (when issued in accordance  with the terms of this  Agreement)
validly issued and outstanding,  fully paid and  nonassessable,  and will not be
subject to any preemptive  rights of the holders of any other class or series of
the capital stock of the Company.  Upon the issuance of the Purchased  Shares to
the Investor at the Closing,  the Purchased Shares will be free and clear of all
Liens of any nature

                                      -24-

<PAGE>



whatsoever,  with the exception of any restrictions on transferability set forth
in the Investment  Agreement or under the Securities Act or any securities  laws
of any jurisdiction.

                  (f) No Brokers. No agent, broker, investment banker, Person or
firm is or  will be  entitled  to any  broker's  or  finder's  fee or any  other
commission  or  similar  fee  directly  or  indirectly  in  connection  with the
transactions   contemplated   by  this  Agreement   based  in  any  way  on  any
arrangements, agreements or understandings made by or on behalf of either Aerial
Party or any Affiliate of either of them,  and the Aerial Parties hereby jointly
and severally  agree to indemnify the Investor and to hold harmless the Investor
against  and in  respect  of any  claims  for  brokerage  and other  commissions
relating to such transactions  based in any way on any arrangements,  agreements
or  understandings  made by or on behalf of either Aerial Party or any Affiliate
of either of them.


                  (g)  Financial  Statements.   EXHIBIT  4.1(g)  annexed  hereto
contains a list of financial  statements of Aerial and its  Subsidiaries for the
periods indicated on such EXHIBIT 4.1(g) (the "Operating Financial Statements").
True and  complete  copies of each item  listed  thereon  have  previously  been
delivered to the Investor. The Operating Financial Statements have been prepared
on  a  consistent  basis  in  accordance  with  generally  accepted   accounting
principles as in effect in the United States, and fairly present in all material
respects the financial position of Aerial and its Subsidiaries,  as of such date
and for the period then ended,  except that any  unaudited  Operating  Financial
Statements are subject to normal year-end adjustments.

                  (h)  Compliance  with  Laws.  Except as set  forth on  EXHIBIT
4.1(c) annexed hereto, each of Aerial and its Subsidiaries is in compliance with
all applicable laws, regulations,

                                      -25-

<PAGE>



administrative  orders and Authorizations of the United States and the states in
which Aerial or its  Subsidiaries  transact  business  (including all applicable
rules,  regulations and Authorizations of the FCC, any state public utilities or
public service commission,  or any other federal or state governmental agency or
instrumentality   exercising   jurisdiction  over  the  Company),  and  of  each
municipality,  county  or  subdivision  of  any  thereof,  to  which  any of its
businesses or any of its  properties  may be subject,  the  non-compliance  with
which would have a Material Adverse Effect.

                  (i)  Authorizations.  (i) Each of Aerial and its  Subsidiaries
has  (A)  all  requisite   Authorizations   of  the  FCC   (including   all  PCS
Authorizations)  and of all state public utility or public  service  commissions
and (B) all other material  Authorizations of governmental  agencies  exercising
jurisdiction over Aerial or any of its Subsidiaries  required to carry on its or
their business as now conducted or as contemplated  to be conducted,  except for
any  Authorizations,  the  failure of which to obtain  would not have a Material
Adverse Effect or a material  adverse effect on any PCS  Authorization.  All PCS
Authorizations  which are contemplated by this Agreement to be held, directly or
indirectly, by Aerial are listed on EXHIBIT 4.1(i) annexed hereto.

                  (ii) All  Authorizations of Aerial and its Subsidiaries are in
full force and  effect and have not been  suspended,  modified  in any  material
adverse  respect,  canceled or revoked,  and each of Aerial and its Subsidiaries
has operated in compliance with all terms thereof  applicable to it except where
failure  to so comply  would not have a  Material  Adverse  Effect or a material
adverse effect on any PCS  Authorization.  No event has occurred or, to the best
knowledge of Aerial and the Company,  is threatened to occur with respect to any
Authorization  of  Aerial or any of its  Subsidiaries  which  permits,  or after
notice or lapse of time or both would permit,  revocation or termination thereof
or would result in any other material  impairment of the rights of the holder of
any such  Authorization,  except to the extent such  revocation,  termination or
impairment would not have a Material Adverse

                                      -26-

<PAGE>


Effect or a  material  adverse  effect on any PCS  Authorization.  Except as set
forth on EXHIBIT  4.1(i) annexed  hereto,  there is not pending nor, to the best
knowledge  of Aerial  and the  Company,  threatened  as of the date  hereof  any
application,  petition,  objection or other  pleading with the FCC or any public
service  commission or similar body having  jurisdiction  or authority  over the
communications  operations of Aerial or any of its Subsidiaries  which questions
the  validity  of, or which  presents a  substantial  risk that,  if accepted or
granted,   would  result  in  the   revocation,   cancellation,   suspension  or
modification  of,  any  such  Authorization,  except  to the  extent  that  such
invalidity, revocation, cancellation,  suspension or modification would not have
a Material Adverse Effect.

                  (j) Taxes.  Aerial and its Subsidiaries  have timely filed all
federal,  state,  county,  local and foreign Tax Returns required to be filed by
them,  and have paid all  Taxes  which  have  become  due  pursuant  thereto  or
otherwise,  other than Taxes the liability for which is being  contested in good
faith  and  appropriate  reserves  for which  have  been  made in the  financial
statements  of Aerial or the  Company.  Except  as set forth on  EXHIBIT  4.1(j)
annexed  hereto,  there are no additional  assessments  or  adjustments of Taxes
pending or  threatened  against  TDS,  Aerial or Aerial's  Subsidiaries  for any
period.

                  (k) No Material Adverse Change. Since December 31, 1997, there
has not been  any  event or  condition,  including  any  change  in the  capital
structure of TDS, Aerial or any of Aerial's  Subsidiaries,  which has caused, or
is reasonably likely to cause, a Material Adverse Effect, other than as a result
of conditions affecting broadband personal communications systems generally.



                                      -27-

<PAGE>



                  (l) Employee  Benefit Plans.  All employee benefit or employee
welfare plans maintained by TDS, Aerial or any of Aerial's  Subsidiaries in each
case for the  benefit of  employees  of Aerial or any of  Aerial's  Subsidiaries
("Aerial  Benefit  Plans") which are subject to the Employee  Retirement  Income
Security Act of 1974, as amended ("ERISA"), comply in all material respects with
the  requirements of ERISA,  and no such Aerial Benefit Plan which is subject to
Part 3 of Subtitle B of Title 1 of ERISA has incurred any  "Accumulated  Funding
Deficiency"  within the  meaning of Section  302 of ERISA or Section  412 of the
Code,  and none of TDS,  Aerial or any  Subsidiary  of Aerial has  incurred  any
liability on account of such an "Accumulated Funding Deficiency" with respect to
any such Aerial  Benefit  Plan  subject to ERISA.  No  liability  to the Pension
Benefit  Guaranty  Corporation  established  under ERISA has been  incurred with
respect to any such Aerial Benefit Plan subject to ERISA and none of TDS, Aerial
or any  Subsidiary  of Aerial has incurred any  liability for any tax implied by
Section  4975 of the  Code.  As of the most  recent  valuation  date of any such
Aerial  Benefit Plan,  there are no "unfunded  benefit  liabilities"  within the
meaning of Section  4001(a)(18) of ERISA;  and no "prohibited  transaction"  has
occurred  within the meaning of Section 4975 of the Code or Section 406 of ERISA
that would subject Aerial or any of its Subsidiaries to tax or penalty.

                  (m) Compliance with other Instruments.  Neither Aerial nor any
of its  Subsidiaries  is in  violation  of any  term  of (i)  any  agreement  or
instrument  related to  indebtedness  for borrowed  money or any other  material
agreement to which it is a party or by which it is bound, or (ii) any applicable
order,  judgment or decree of any court,  arbitrator or governmental  authority,
the consequences of which violation,  whether  individually or in the aggregate,
would result in a Material Adverse Effect. Neither Aerial Party is a party to or
bound by any agreement, instrument or constituent document compliance with which
could reasonably be expected to result in a Material Adverse Effect.

                                      -28-

<PAGE>



                  (n)  Organization  of  Subsidiaries.  Each  Subsidiary  of the
Company is listed on EXHIBIT 4.1(n) annexed hereto and is a corporation or other
legal  entity  duly  organized  and in  good  standing  under  the  laws  of the
jurisdiction  of its  organization  and is duly qualified and has the full power
and authority in each applicable  jurisdiction to own its properties and conduct
its business and  operations as currently  conducted,  except to the extent that
any failure to qualify would not have a Material  Adverse Effect.  Except as set
forth in  Exhibit  4.1(n),  none of  Aerial or any of its  Subsidiaries  has any
equity investment, or holds any interest convertible into equity, in any Person.

                  (o) Capital  Stock.  After giving  effect to the filing of the
amendment to the Company's Certificate of Incorporation  contemplated by Section
3.1(f) hereof and the Closing hereunder,  12,410,482 shares of Common Stock will
be outstanding, of which 10,000,000 shares shall have been issued to Aerial, and
2,410,482  shares shall have been issued to the Investor,  and such shares shall
constitute all of the  outstanding  capital stock of the Company  (including all
outstanding interests convertible into capital stock). All outstanding shares of
the  capital  stock of the  Company  at the date  hereof are (and will after the
Closing be) duly authorized,  validly issued, fully paid and nonassessable,  and
no class of capital  stock of the  Company  will at the  Closing be  entitled to
preemptive rights,  other than as set forth in the Certificate of Incorporation,
as  amended.  Except as  contemplated  in the  Investment  Agreement,  there are
outstanding no options, warrants or other obligations or rights of any Person to
issue, redeem,  repurchase,  cancel, exchange,  convert or acquire capital stock
from Aerial or the Company.

                  (p) Investment Company Act. None of Aerial or its Subsidiaries
is, or will become as a result of the Closing,  an "investment  company"  within
the meaning of the Investment Company Act of 1940, as amended.

                                      -29-

<PAGE>



                  4.2  Representations  and  Warranties  of  the  Investor.  The
Investor  represents  and  warrants  to  TDS  and  the  Aerial  Parties,   which
representations  and warranties shall survive the execution and delivery of this
Agreement and the  consummation  of the  transactions  contemplated  hereby,  as
follows:

                  (a) Due  Organization.  The  Investor  is a limited  liability
company duly organized,  validly existing and in good standing under the laws of
Finland.  The Investor is duly  qualified to do business and is in good standing
in all  jurisdictions  where the conduct of its business or the ownership of its
properties makes such  qualification  necessary,  except where the failure to so
qualify  would  not  have a  material  adverse  effect  on the  Investor  or its
financial condition, or the transactions contemplated hereby.

                  (b) Power and Authority;  No Violation.  The Investor has, and
prior to the Closing  Date Sonera U.S.  will have,  full power and  authority to
execute,  deliver and  perform  its  obligations  under this  Agreement  and the
Additional  Agreements,  as  applicable,  and  to  consummate  the  transactions
contemplated  hereby or thereby, as applicable.  This Agreement,  the Additional
Agreements and all  transactions  contemplated  hereby or thereby have been duly
and validly authorized by all necessary action on the part of the Investor,  and
prior to the  Closing  Date the Joint  Venture  Agreement  and all  transactions
contemplated thereby will have been duly and validly authorized by all necessary
action on the part of Sonera  U.S.,  and,  assuming  the due  authorization  and
execution  of this  Agreement  by TDS and the  Aerial  Parties,  this  Agreement
constitutes a legal, valid and binding  obligation of the Investor,  enforceable
in accordance with its terms,  except as such  enforceability  may be limited by
bankruptcy,  insolvency,  reorganization,   moratorium  or  other  similar  laws
affecting or relating to enforcement of creditors' rights  generally.  Except as
described on EXHIBIT 4.2(b) annexed hereto,  neither the execution,  delivery or
performance of this Agreement

                                      -30-

<PAGE>



or, upon their execution, the Additional Agreements, nor the consummation of the
transactions   contemplated   hereby  or  thereby  by  the  Sonera  Parties,  as
applicable,  will,  with or without the giving of notice or the passage of time,
or both,  (i) conflict  with,  violate,  result in a default,  breach or loss of
rights (or give rise to any right of termination,  cancellation or acceleration)
under,  or result in the creation of any Lien,  pursuant to (A) any provision of
the Certificates of Incorporation or By-laws, or other constituent  documents of
either Sonera Party, (B) any material note, bond, indenture,  mortgage,  deed of
trust,  contract,  agreement,  lease or other  instrument or obligation to which
either  Sonera Party is a party or by which  either of them or their  respective
property may be bound or affected, or (C) any law, order,  judgment,  ordinance,
rule,  regulation  or decree to which either Sonera Party is a party or by which
either of them or their respective  property is bound or affected,  or (ii) give
rise to any  right of  first  refusal  or  similar  right  with  respect  to any
interest,  or any properties or assets, of either Sonera Party that, in the case
of either  clause  (i) or (ii),  would  have a  material  adverse  effect on the
ability or  capacity  of either  Sonera  Party to  execute  and  deliver,  or to
consummate the transactions  contemplated by or perform their obligations under,
this  Agreement  or any  Additional  Agreement.  Except as  described on EXHIBIT
4.2(b)   annexed   hereto,   no  permit,   consent,   approval,   authorization,
qualification  or  registration  of,  or  declaration  to or  filing  with,  any
governmental or regulatory authority or agency or any third party is required to
be obtained or made by either Sonera Party in connection  with the execution and
delivery  of,  and  performance  by  either  Sonera  Party of  their  respective
obligations under, this Agreement or the Additional  Agreements,  as applicable,
or the  consummation  by either  Sonera Party of the  transactions  contemplated
hereby or  thereby,  as  applicable,  in order to  render  this  Agreement,  the
Additional Agreements and the transactions  contemplated hereby or thereby valid
and effective.

                  (c)      Legal Matters.  Except as set forth on EXHIBIT 4.2(c)
annexed hereto, there is no claim, legal action, counterclaim, suit, 
arbitration, governmental investigation or other legal, administrative or tax

                                      -31-

<PAGE>



proceeding,  or any order, decree or judgment, in progress or pending, or to the
knowledge of the Investor threatened,  against or relating to the right of 
either Sonera Party to execute and deliver this Agreement or the Additional  
Agreements,  as applicable,  or perform its  obligations  under this Agreement 
or the Additional Agreements, as applicable, nor does Investor know of any  
basis for the  same.  There is  outstanding  no  order,  writ,  injunction,
judgment or decree of any court,  governmental  agency or  arbitration  tribunal
which would  individually or in the aggregate impair in any material respect the
performance  of the  obligations  of either Sonera Party  hereunder or under the
Additional  Agreements,  as applicable,  or the consummation of the transactions
contemplated hereby or thereby.

                  (d) Securities Representation. The Investor acknowledges that:
(i) it is not a "U.S.  person" (as defined in Rule 902 under the Securities Act)
and, in  determining  to acquire the Purchased  Shares  hereunder,  has made its
buying decision outside the United States; (ii) it is an accredited investor (as
defined in Rule 501 under the Securities  Act);  (iii) it has such knowledge and
experience  in financial  and business  matters that it is capable of evaluating
the merits and risks of  investing  in the  Company as  contemplated  hereby or,
alternatively, that it has engaged the services of a representative who has such
knowledge and  experience in financial and business  matters as to be capable of
evaluating the merits and risks of the proposed  investment and who has reviewed
the proposed investment on its behalf; (iv) the Purchased Shares to be delivered
by the  Company to the  Investor at the  Closing  Date have not been  registered
under the Securities  Act or under the securities  laws of any state in reliance
upon  federal  and state  exemptions  for  transactions  not  involving a public
offering  and are not being  acquired  with a view to the  distribution  thereof
except pursuant to a registration statement in compliance with federal and state
securities laws or an exemption therefrom; (v) the Purchased Shares must be held
by the Investor  indefinitely  unless subsequently so registered or an exemption
from such registration is available; and (vi) it has

                                      -32-

<PAGE>



received  information  concerning  Aerial  and  the  Company  and  has  had  the
opportunity to obtain additional information as desired in order to evaluate the
merits and risks inherent in holding the Purchased  Shares.  The Investor agrees
that the share certificate(s) which the Investor receives from the Company shall
be legended with the following legends:

                  "THE  SHARES  REPRESENTED  BY THIS  CERTIFICATE  HAVE NOT BEEN
                  REGISTERED  UNDER THE  SECURITIES ACT OF 1933, AS AMENDED (THE
                  "ACT"), AND NO TRANSFER OR OTHER  DISTRIBUTION  THEREOF CAN BE
                  MADE IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT FOR
                  THE   SHARES   UNDER  THE  ACT,   OR  AN  OPINION  OF  COUNSEL
                  SATISFACTORY TO THE COMPANY THAT  REGISTRATION IS NOT REQUIRED
                  UNDER THE ACT OR ANY APPLICABLE  STATE  SECURITIES  LAWS." AND
                  "THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO
                  CERTAIN  RESTRICTIONS  ON TRANSFER  AND VOTING SET FORTH IN AN
                  INVESTMENT  AGREEMENT  DATED AS OF _________,  1998. A COPY OF
                  SUCH AGREEMENT MAY BE OBTAINED FROM THE COMPANY UPON REQUEST."

                  (e)  Investment  Company  Act.  The  Investor is not, nor will
become as a result of the Closing, an "investment company" within the meaning of
the Investment Company Act of 1940, as amended.

                  (f)      Truth and Correctness.  No representation or warranty
by the Investor in this Agreement or any Additional Agreement contains or will
contain any untrue statement of a material

                                      -33-

<PAGE>



fact or  omits or will  omit to  state a  material  fact  necessary  to make the
statements  contained  herein or therein,  in light of the  circumstances  under
which such statements are made, not misleading.

                  (g)  No  Brokers.   Except  for  Credit  Suisse  First  Boston
Corporation,  no agent, broker,  investment banker, Person or firm is or will be
entitled to any broker's or finder's fee or any other  commission or similar fee
directly or indirectly in connection with the transactions  contemplated by this
Agreement  based in any way on any  arrangements,  agreements or  understandings
made by or on behalf of the Investor or any Affiliate thereof,  and the Investor
hereby agrees to indemnify  TDS and the Aerial  Parties and to hold harmless TDS
and the Aerial  Parties  against and in respect of any claims for  brokerage and
other  commissions  relating  to  such  transactions  based  in  any  way on any
arrangements,  agreements or understandings made by or on behalf of the Investor
or any Affiliate of the Investor.

                  (h) No  Interest  in FCC  Licenses.  Except  as set  forth  in
Exhibit 4.2(h) annexed hereto,  neither the Investor nor any of its Subsidiaries
has any license to provide or is providing, or owns, directly or indirectly, any
interest  in any entity  which has a license  to provide or which is  providing,
commercial  mobile radio services in the United States,  nor has the Investor or
any of its Subsidiaries entered into any agreement or other arrangement with any
Person (other than an Aerial Party) to acquire such a license or interest.

                  4.3  Representations and Warranties of TDS. TDS represents and
warrants to Sonera,  which  representations  and  warranties  shall  survive the
execution  and  delivery  of  this  Agreement  and  the   consummation   of  the
transactions contemplated hereby, as follows:

                                      -34-

<PAGE>



                  (a) Due  Organization.  TDS is a corporation duly incorporated
and  validly  existing  under  the laws of the  State of  Delaware.  TDS is duly
qualified to do business and is in good standing in all jurisdictions  where the
conduct  of  its  business  or  the  ownership  of  its  properties  makes  such
qualification necessary, except where the failure to so qualify would not have a
Material Adverse Effect.

                  (b) Power and Authority; No Violation.  TDS has full power and
authority to execute,  deliver and perform its obligations  under this Agreement
and to consummate the transactions  contemplated  hereby. This Agreement and any
transactions  contemplated  hereby have been duly and validly  authorized by all
necessary  action  on the part of TDS and this  Agreement  constitutes  a legal,
valid and binding  obligation of TDS  enforceable in accordance  with its terms,
except  as  such  enforceability  may  be  limited  by  bankruptcy,  insolvency,
reorganization,  moratorium  or other  similar  laws  affecting  or  relating to
enforcement of creditors' rights generally.  Neither the execution,  delivery or
performance of this Agreement,  nor the  consummation by TDS of the transactions
contemplated hereby will, with or without the giving of notice or the passage of
time, or both, (i) conflict with, violate,  result in a default,  breach or loss
of  rights  (or  give  rise  to  any  right  of  termination,   cancellation  or
acceleration)  under, or result in the creation of any Lien, pursuant to (A) any
provision of the Restated  Certificate (as defined in the Investment  Agreement)
or By-laws of TDS, (B) any material note,  bond,  indenture,  mortgage,  deed of
trust, contract, agreement, lease or other instrument or obligation to which TDS
is a party or by which TDS or any of its property may be bound,  or (C) any law,
order,  judgment,  ordinance,  rule, regulation or decree to which TDS or any of
its  property  is  bound,  or (ii)  give  rise to any  right of  first  refusal,
subscription or similar right with respect to any interest in, or any properties
or assets of, TDS or any of its  Subsidiaries.  Except as  described  on EXHIBIT
4.1(b)   annexed   hereto,   no  permit,   consent,   approval,   authorization,
qualification  or  registration  of,  or  declaration  to or  filing  with,  any
governmental or regulatory authority

                                      -35-

<PAGE>



or agency or any third party is required to be obtained or made by TDS or any of
its  Subsidiaries  in  connection  with  the  execution  and  delivery  of,  and
performance by TDS of its  obligations  under,  this  Agreement,  the Additional
Agreements,  or the consummation by TDS of the transactions  contemplated hereby
or thereby, in order to render this Agreement, the Additional Agreements and the
transactions contemplated hereby or thereby valid and effective.

                  (c)  Legal   Matters.   There  is  no  claim,   legal  action,
counterclaim,  suit,  arbitration,  governmental  investigation  or other legal,
administrative or tax proceeding, nor any order, decree or judgment, in progress
or pending,  or to the knowledge of TDS  threatened,  against or relating to the
right of TDS to execute and deliver this  Agreement  or perform its  obligations
hereunder,  or which could  reasonably  be  expected to have a Material  Adverse
Effect on TDS, nor does TDS know of any basis for the same. There is outstanding
no order, writ, injunction, judgment or decree of any court, governmental agency
or  arbitration  tribunal  which,  individually  or  in  the  aggregate,   could
reasonably  be expected  to have a Material  Adverse  Effect on TDS,  other than
orders or decrees involving the wireless telephone industry in general.

                  (d) Truth and Correctness.  No  representation  or warranty by
TDS in this  Agreement  contains  or will  contain  any  untrue  statement  of a
material fact or omits or will omit to state a material  fact  necessary to make
the statements  contained herein, in light of the circumstances under which such
statements are made, not misleading.

                  (e)  Compliance  with  Laws.  Except as set  forth on  EXHIBIT
4.3(e) annexed  hereto,  each of TDS and its  Subsidiaries is in compliance with
all applicable laws,  regulations,  administrative  orders and authorizations of
the United States and States in which they transact their respective  businesses
(including all applicable rules, regulations and authorizations of FCC, any

                                      -36-

<PAGE>



state public  utilities or public  service  commission,  or any other federal or
state governmental agency or instrumentality  exercising jurisdiction over TDS),
and of each municipality,  county or subdivision of any thereof, to which any of
their  respective  businesses  or  any of  their  respective  properties  may be
subject, the non-compliance with which would have a Material Adverse Effect.

                  (f)  Authorization.  Each of TDS and its  Subsidiaries has (i)
all requisite  Authorizations of the FCC (including all PCS  Authorizations) and
of all state public  utility or public  service  commissions  and (ii) all other
material  Authorizations of governmental  agencies exercising  jurisdiction over
TDS or such Subsidiary,  respectively,  required to carry on its business as now
conducted or as contemplated to be conducted, except for any Authorizations, the
failure of which to obtain would not have a Material Adverse Effect.

                  (g) Taxes.  TDS and its  Subsidiaries  have  timely  filed all
federal,  state,  county,  local and foreign Tax Returns required to be filed by
them,  and have paid all  Taxes  which  have  become  due  pursuant  thereto  or
otherwise,  other than Taxes the liability for which is being  contested in good
faith  and  appropriate  reserves  for which  have been made in TDS's  financial
statements.  Except to the extent set forth on EXHIBIT  4.3(g) annexed hereto or
appropriately  reserved  for  in  TDS's  financial  statements,   there  are  no
additional assessments or adjustments of Taxes pending or threatened against TDS
or its Subsidiaries for any period.

                  (h) No Material Adverse Change. Since December 31, 1997, there
has not been any event or condition which has caused, or is reasonably likely to
cause,  a Material  Adverse  Effect on TDS, other than as a result of conditions
affecting the U.S. telecommunications industry generally.



                                      -37-

<PAGE>



                                    ARTICLE 5

                            CONDITIONS TO OBLIGATIONS

                  5.1  Conditions  to the  Obligation  of  TDS  and  the  Aerial
Parties.  The  obligation  of TDS and each of the Aerial  Parties to perform its
obligations  hereunder is and shall be subject to  fulfillment  of or compliance
with, on or prior to the Closing Date, the following conditions  precedent,  any
of which may be waived in writing  by TDS and the  Aerial  Parties in their sole
discretion, in whole or in part:

                  (a)   Representations   and  Warranties   True.  Each  of  the
representations and warranties of the Investor contained in this Agreement shall
be deemed to have been made at and as of the time of the Closing  Date and shall
then be true in all material  respects.  The Investor  shall have  performed and
complied in all material respects with all agreements and covenants  required by
this Agreement to be performed or complied with by it prior to or at the Closing
Date. TDS and the Aerial Parties shall have been furnished with a certificate of
the Investor signed by one of its senior executive  officers,  dated the Closing
Date, certifying to the fulfillment of the foregoing conditions by it and to the
truth and correctness in all material respects,  except for changes contemplated
by this Agreement, as of the Closing Date, of the representations and warranties
made by it contained  herein and the  satisfaction on its part of all conditions
to the obligations of TDS and the Aerial Parties under this Section 5.1.

                  (b) No Suit  Pending.  There  shall not then be pending by any
third party any suit or  proceeding  to restrain or  invalidate,  in whole or in
part, this Agreement or the transactions contemplated hereby.

                                      -38-

<PAGE>



                  (c) Opinions of Counsel. TDS and the Aerial Parties shall have
been furnished with an opinion of Patton Boggs,  L.L.P.,  counsel for the Sonera
Parties,  and, as necessary  with respect to matters of foreign law,  such other
counsel  for the Sonera  Parties,  reasonably  acceptable  to TDS and the Aerial
Parties, dated the Closing Date.

                  (d) HSR Act. The waiting  periods,  if applicable,  of the HSR
Act shall have expired or been terminated.

                  (e) Consents Obtained.  All consents,  waivers,  approvals and
actions  of  third  parties   including  all  necessary  waivers  and  approvals
identified  on Exhibits  4.1(b) and 4.2(b) shall have been  obtained (and in the
case of FCC  waivers or  approvals  pursuant  to a Final  Order) or made  (which
consents, waivers and approvals shall not contain any conditions or restrictions
which,  in  the  case  of  FCC  waivers  or  approvals,  are  not  customary  in
transactions  of this nature).  Notwithstanding  anything to the contrary herein
contained,  it shall not be a condition to the obligations of TDS and the Aerial
Parties under this  Agreement for the Sonera  Parties to obtain each  individual
required  waiver or consent (other than any waivers or consents of the FCC or of
any public utility or public service  commission or comparable  body  exercising
jurisdiction over the Sonera Parties), so long as the failure to obtain any such
individual  waiver or consent would not  individually  or together with all such
other failures to obtain  waivers or consents have a material  adverse effect on
the ability of the Sonera Parties to enter into and consummate the  transactions
contemplated by, and lawfully perform their  obligations  under,  this Agreement
and  the  Additional  Agreements,   as  applicable,  in  accordance  with  their
respective terms.

                  (f)      Purchase Price.  The Investor shall have delivered
the Purchase Price to the Company as required hereby.

                                      -39-

<PAGE>



                  (g)  Resolutions.  TDS and the Aerial  Parties shall have been
furnished with certified copies of the resolutions duly adopted by the boards of
directors of each of the Sonera Parties authorizing the execution,  delivery and
performance of this Agreement and the Additional Agreements, as applicable.

                  (h) No New Statutes. No statute, rule or regulation shall have
been enacted by any state or federal  government or  governmental  agency in the
United States or Finland which would render the  consummation  of this Agreement
or the Additional Agreements unlawful.

                  (i)      Additional Agreements.  TDS, the Aerial Parties and
the Sonera Parties, as applicable, shall have executed and delivered the
Additional Agreements.

                  5.2  Conditions  to  the  Obligation  of  the  Investor.   The
obligation of the Investor to perform its obligations  hereunder is and shall be
subject to fulfillment  of or compliance  with, on or prior to the Closing Date,
the following conditions precedent, any of which may be waived in writing by the
Investor, in its sole discretion, in whole or in part.

                  (a)   Representations   and  Warranties   True.  Each  of  the
representations  and  warranties of the TDS Parties  contained in this Agreement
shall be deemed to have been made at and as of the time of the Closing  Date and
shall then be true in all material respects.  TDS and each of the Aerial Parties
shall have  performed and complied in all material  respects with all agreements
and covenants  required by this Agreement to be performed or complied with by it
prior to or at the Closing Date.  The Investor  shall have been furnished with a
certificate  of each of the TDS Parties,  signed by one of its senior  executive
officers, dated the Closing Date, certifying to the fulfillment of the foregoing
conditions  by it and to the truth and  correctness  in all  material  respects,
except for

                                      -40-

<PAGE>



changes  contemplated  by  this  Agreement,  as of  the  Closing  Date,  of  the
representations and warranties made by the TDS Parties contained herein, and the
satisfaction  on its part of all  conditions to the  obligations of the Investor
under this Section 5.2.

                  (b) No Suit  Pending.  There  shall not then be pending by any
third party any suit or  proceeding  to restrain or  invalidate,  in whole or in
part, this Agreement or the transactions contemplated hereby.

                  (c) Opinion of Counsel. The Investor shall have been furnished
with an opinion  of Sidley & Austin,  counsel  for TDS and the  Aerial  Parties,
reasonably acceptable to Sonera, dated the Closing Date.

                  (d)  Opinion  of FCC  Counsel.  The  Investor  shall have been
furnished  with an opinion of Koteen &  Naftalin,  FCC  counsel  for TDS and the
Aerial Parties, reasonably acceptable to Sonera, dated the Closing Date.

                  (e) HSR Act. The waiting  periods,  if applicable,  of the HSR
Act shall have expired or been terminated.

                  (f) Consents Obtained.  All consents,  waivers,  approvals and
actions of third  parties  identified  in Exhibits  4.1(b) and 4.2(b) shall have
been obtained  (and in the case of FCC waivers or approvals  pursuant to a Final
Order),  or made (which  consents,  waivers and approvals  shall not contain any
conditions or restrictions  which, in the case of FCC waivers or approvals,  are
not customary in transactions of this nature).  Notwithstanding  anything to the
contrary herein contained, it shall not be a condition to the obligations of the
Investor under this Agreement for the

                                      -41-

<PAGE>



Aerial Parties to obtain each individual  required waiver or consent (other than
any waivers or consents  of the FCC or of any public  utility or public  service
commission or comparable body exercising  jurisdiction over the Aerial Parties),
so long as the failure to obtain any such individual waiver or consent would not
individually  or  together  with all such other  failures  to obtain  waivers or
consents have a Material Adverse Effect.

                  (g)   Stock Certificates.  The Company shall have delivered to
the Investor duly issued stock certificates representing the Purchased Shares.

                  (h)  Resolutions.  The Investor shall have been furnished with
certified  copies of the resolutions  duly adopted by the boards of directors of
TDS and each of the Aerial  Parties  authorizing  the  execution,  delivery  and
performance of this Agreement and the  Additional  Agreements,  and Aerial shall
have  delivered a certified  copy of  resolutions  duly  adopted by its board of
directors  electing the designees of the Investor to Aerial's board of directors
effective as of the Closing in accordance with the Investment Agreement.

                  (i) No New Statutes. No statute, rule or regulation shall have
been enacted by any state or federal  government or  governmental  agency in the
United States or Finland which would render the  consummation  of this Agreement
or the Additional Agreements unlawful.

                  (j)  Additional  Agreements.  TDS, the Aerial  Parties and the
Sonera Parties, as applicable,  shall have executed and delivered the Additional
Agreements.

                                      -42-

<PAGE>



                  (k)  Certain  Intercompany  Agreements.  TDS  and  the  Aerial
Parties,  as  applicable,  shall have executed and delivered (i) the Amended Tax
Allocation Agreement, and (ii) the AOC Revolving Credit Agreement.

                                    ARTICLE 6

                               SURVIVAL; INDEMNITY

                  6.1    Survival    of    Representations    and    Warranties.
Notwithstanding  any investigation or review made at any time by or on behalf of
any party hereto, all representations and warranties contained in this Agreement
or in the EXHIBITS  annexed hereto or in any of the agreements,  certificates or
instruments delivered in connection herewith shall survive until the termination
of the Indemnification Period and shall thereupon expire together with any right
to  indemnification  (except  with  respect  to any claim for breach of any such
representation  or warranty for which written notice shall have been given prior
to the  termination of the  Indemnification  Period to the party which made such
representation or warranty).

                  6.2  Indemnity by TDS and the Aerial  Parties.  (a) (i) During
the  Indemnification  Period (or thereafter solely with respect to any claim for
which   indemnification   has  been  made  prior  to  the   expiration   of  the
Indemnification  Period), in addition to any other indemnification  provided for
under this Agreement or any Additional  Agreement,  (A) the Company (and, solely
to the extent the Company is unable to do so,  Aerial) shall  indemnify and hold
harmless the Investor and its officers,  directors,  agents and  representatives
from and against any and all demands,  claims, losses,  liabilities,  actions or
causes of action,  assessments,  actual  damages  (but  excluding  consequential
damages),  fines, Taxes (including excise and penalty Taxes),  penalties,  costs
and expenses,

                                      -43-

<PAGE>



including interest, expenses of investigation, reasonable fees and disbursements
of counsel,  accountants and other experts (collectively,  "Losses") incurred or
suffered by any such  indemnified  Person  arising out of,  resulting  from,  or
relating to any breach of any of the  representations  or warranties made by the
Aerial Parties in this Agreement or in any  agreement,  certificate,  EXHIBIT or
other instrument  delivered by the Aerial Parties pursuant to this Agreement and
(B) TDS  shall  indemnify  and hold  harmless  the  Investor  and its  officers,
directors,  agents  and  representatives  from and  against  any and all  Losses
incurred or suffered by any such  indemnified  Person arising out of,  resulting
from or relating to any breach of any of the representations and warranties made
by TDS in this  Agreement  or in any  agreement,  certificate,  EXHIBIT or other
instrument delivered by TDS pursuant to this Agreement.

                  (ii) In addition  to any other  indemnification  provided  for
under this Agreement or any Additional  Agreement,  (A) the Company (and, solely
to the extent the Company is unable to do so,  Aerial) shall  indemnify and hold
harmless the Investor and its officers,  directors,  agents and  representatives
from and against any and all Losses incurred or suffered by any such indemnified
Person arising out of,  resulting  from, or relating to any failure by either of
the Aerial  Parties to perform any of its covenants or  agreements  contained in
this Agreement or in any agreement, certificate or other instrument delivered by
it pursuant to this Agreement and (B) TDS shall  indemnify and hold harmless the
Investor  and its  officers,  directors,  agents  and  representatives  from and
against any and all Losses incurred of suffered by any such  indemnified  Person
arising out of,  resulting from or relating to any failure by TDS to perform any
of its covenants or agreements  contained in this Agreement or in any agreement,
certificate or other instrument delivered by it pursuant to this Agreement.

                                      -44-

<PAGE>



                  (b) Notwithstanding anything to the contrary contained in this
Section  6.2,  none of TDS,  Aerial or the  Company  shall be required to pay or
reimburse  the  Investor  for  Losses  pursuant  to  any  of  their   respective
indemnification  obligations  pursuant to this Section 6.2, unless the aggregate
amount of Losses claimed by the Investor in respect of all such matters  exceeds
$500,000,  in which event the Investor shall be entitled to seek indemnification
under this Section 6.2 for the entire amount of all such Losses.

                  6.3   Indemnity   by  the   Investor.   (a)  (i)   During  the
Indemnification Period (or thereafter solely with respect to any claim for which
indemnification  has been made prior to the  expiration  of the  Indemnification
Period),  in  addition  to any other  indemnification  provided  for under  this
Agreement or any Additional  Agreement,  the Investor  shall  indemnify and hold
harmless TDS and the Aerial Parties and their  respective  officers,  directors,
agents and  representatives  from and  against  any and all Losses  incurred  or
suffered by any such  indemnified  person  arising out of,  resulting  from,  or
relating to any breach of any of the  representations  or warranties made by the
Sonera Parties in this Agreement or in any  agreement,  certificate,  EXHIBIT or
other instrument delivered by the Sonera Parties pursuant to this Agreement,  as
applicable.

                  (ii) In addition  to any other  indemnification  provided  for
under this Agreement or any Additional  Agreement,  the Investor shall indemnify
and hold  harmless  TDS and the Aerial  Parties and their  respective  officers,
directors,  agents  and  representatives  from and  against  any and all  Losses
incurred or suffered by any such  indemnified  Person arising out of,  resulting
from, or relating to any failure by either of the Sonera  Parties to perform any
of its covenants or agreements  contained in this Agreement or in any agreement,
certificate or other instrument  delivered by it pursuant to this Agreement,  as
applicable.

                                      -45-

<PAGE>



                  (b) Notwithstanding anything to the contrary contained in this
Section  6.3,  the  Investor  shall not be required to pay or  reimburse  TDS or
either  Aerial  Party  for  Losses  pursuant  to  any  of  the   indemnification
obligations  pursuant to this Section 6.3, unless the aggregate amount of Losses
claimed by TDS and the Aerial  Parties  in respect of all such  matters  exceeds
$500,000,  in which event TDS and the Aerial  Parties  shall be entitled to seek
indemnification under this Section 6.3 for the entire amount of all such Losses.

                  6.4 Procedure.  (a) Notice of Claim;  Assumption of Defense by
Indemnitor.  In the event  that any  Person  hereto  shall  sustain or incur any
Losses in respect of which  indemnification  may be sought by such  Person  (the
"Indemnitee")  pursuant to this Article 6, the  Indemnitee  shall assert a claim
for indemnification by giving prompt notice to the indemnifying party or parties
(collectively,  the  "Indemnitor")  and  shall  thereafter  keep the  Indemnitor
reasonably  informed  with  respect  thereto;   provided  that  failure  of  the
Indemnitee to give the  Indemnitor  notice as provided  herein shall not relieve
the Indemnitor of any of its  obligations  hereunder,  except to the extent that
the  Indemnitor  is materially  prejudiced  by such failure.  In case a claim is
brought against any Indemnitee,  the Indemnitor  shall have the right to assume,
conduct and control the defense,  compromise or settlement  thereof,  by written
notice to the  Indemnitee of its intention to do so within 30 days after receipt
of the notice,  with counsel reasonably  satisfactory to the Indemnitee,  at the
Indemnitor's  own expense,  and thereupon to prosecute in the name and on behalf
of the  Indemnitee  any available  cross-claims,  counterclaims  or  third-party
claims  arising with respect to the claim.  If the  Indemnitor  shall assume the
defense of such  claim,  it shall not settle such claim  unless such  settlement
includes as an  unconditional  term  thereof  the giving by the  claimant or the
plaintiff  of a  release  of  the  Indemnitee,  reasonably  satisfactory  to the
Indemnitee,  from all  liability  with  respect  to such  claim and any  related
claims. As long as the Indemnitor is contesting any such claim in good faith and
on a timely  basis,  the  Indemnitee  shall  not pay or settle  any such  claim.
Notwithstanding

                                      -46-

<PAGE>



the assumption by the Indemnitor of the defense of any claim as provided in this
Section 6.4 and without limiting the Indemnitor's  right to assume,  conduct and
control the defense,  compromise or settlement thereof,  the Indemnitee shall be
permitted to join in the defense of such claim and to employ  counsel at its own
expense.  Assumption by the  Indemnitor of the defense of any claim shall not be
deemed a  concession  by the  Indemnitor  that it is required to  indemnify  the
Indemnitee for the subject matter of such claim.

                  (b)  Assumption of Defense by  Indemnitee.  If the  Indemnitor
shall fail to notify the  Indemnitee  of its desire to assume the defense of any
such  claim  within the  prescribed  30-day  period set forth in Section  6.4(a)
hereof,  or shall notify the  Indemnitee  that it will not assume the defense of
any such claim, then the Indemnitee may assume the defense of any such claim, in
which  event it may do so in such  manner  as it may deem  appropriate,  and the
Indemnitor  shall be bound by any  determinations  made in any  litigation  with
respect to such claim or any  settlement  thereof  effected  by the  Indemnitee,
provided that any such  determinations  or settlement shall not affect the right
of the Indemnitor to dispute the Indemnitee's claim for indemnification.

                  (c)  Payments.  Amounts  payable  by  the  Indemnitor  to  the
Indemnitee  in  respect  of any  Losses  for which any  Person  is  entitled  to
indemnification  hereunder shall be payable by the Indemnitor as incurred by the
Indemnitee. Any payments by any Indemnitor in indemnification hereunder shall be
treated as adjustments to the Purchase Price.

                  6.5  Indemnity  Sole Remedy.  In the absence of fraud or of an
action seeking  equitable  remedies or relief as contemplated by this Agreement,
the  remedies  provided  to TDS,  the Aerial  Parties  and the  Investor  by the
foregoing provisions of this Article 6 shall after the Closing Date

                                      -47-

<PAGE>



be in lieu of any other  remedies to which the  respective  party is entitled at
law or in equity for any breach or  noncompliance by a party with the provisions
of this Agreement.

                                    ARTICLE 7

                                  MISCELLANEOUS

                  7.1 Expenses.  Each party shall bear its own expenses incident
to  the  negotiation,  preparation,   authorization  and  consummation  of  this
Agreement  and the  transactions  contemplated  hereby,  including  all fees and
expenses of its counsel and  accountants,  whether or not such  transactions are
consummated.

                  7.2  Equitable   Remedies.   The  parties  hereto  agree  that
irreparable  damage would occur in the event that any of the  provisions of this
Agreement  were not  performed  in  accordance  with the  specific  terms of the
provisions or were otherwise breached. It is accordingly agreed that the parties
shall be entitled to an injunction or  injunctions  to prevent  breaches of this
Agreement and to enforce  specifically  the terms and  provisions  hereof in any
court of the  United  States or any state  having  jurisdiction,  this  being in
addition  to any other  remedy to which they are  entitled  at law or in equity.
Each party  agrees  that it will not  assert,  as a defense  against a claim for
specific  performance  or other  equitable  remedy,  that the party seeking such
equitable remedy has an adequate remedy at law.

                  7.3  Notices.  All  notices,  claims and other  communications
hereunder shall be in writing and shall be made by hand delivery,  facsimile, or
overnight air courier guaranteeing next day delivery

                                      -48-

<PAGE>





                  (a)      if to TDS, at:

                           Telephone and Data Systems, Inc.

                           30 North LaSalle Street

                           Suite 4000

                           Chicago, Illinois  60602

                           Attention:  Mr. LeRoy T. Carlson, Jr.

                           Phone:           (312) 630-1900

                           Fax:             (312) 630-9299

                  with a copy (which shall not constitute notice) to:

                           Aerial Communications, Inc.

                           8410 West Bryn Mawr Avenue

                           Suite 1100

                           Chicago, Illinois  60631

                           Attention:  Mr. Donald W. Warkentin

                           Phone:           (773) 399-4145

                           Fax:             (773) 399-7997

                  with a copy (which shall not constitute notice) to:

                           Sidley & Austin

                           One First National Plaza

                           42nd Floor - SW

                           Chicago, Illinois  60603

                           Attention:  Michael G. Hron, Esq.

                           Phone:           (312) 853-2030

                           Fax:             (312) 853-7036

                                      -49-

<PAGE>



                  (b)      if to either Aerial Party, at:

                           Aerial Communications, Inc.

                           8410 West Bryn Mawr Avenue

                           Suite 1100

                           Chicago, Illinois  60631

                           Attention:  Mr. Donald W. Warkentin

                           Phone:           (773) 399-4145

                           Fax:             (773) 399-7997

                  with a copy (which shall not constitute notice) to:

                           Telephone and Data Systems, Inc.

                           30 North LaSalle Street

                           Suite 4000

                           Chicago, Illinois  60602

                           Attention:  Mr. LeRoy T. Carlson, Jr.

                           Phone:           (312) 630-1900

                           Fax:             (312) 630-9299

                  with a copy (which shall not constitute notice) to:

                           Sidley & Austin

                           One First National Plaza

                           42nd Floor - SW

                           Chicago, Illinois  60603

                           Attention:  Michael G. Hron, Esq.

                           Phone:           (312) 853-2030

                           Fax:             (312) 853-7036



                                      -50-

<PAGE>



                  (c)      if to Sonera, at:

                           Sonera Corporation

                           P.O. Box 106

                           FIN-00051-TELE

                           Teollisuuskatu 15, HELSINKI

                           Attention:  Maire Laitinen, Esq.

                           Phone:           011-35-8-2040-3641

                           Fax:             011-35-8-2040-3414

                  with a copy (which shall not constitute notice) to:

                           Patton Boggs, L.L.P.

                           2550 M. Street, N.W.

                           Washington, D.C.  20037-1350

                           Attention:  Richard M. Stolbach, Esq.

                           Phone:           (202) 457-6324

                           Fax:             (202) 457-6315

or at such other address as any party may from time to time furnish to the other
parties by a notice given in accordance with the provisions of this Section 7.3.
All  such  notices  and  communications  shall be  delivered  by hand or sent by
facsimile or overnight air courier  service  guaranteeing  next day delivery and
shall be  deemed  to have  been duly  given at the time  delivered  by hand,  if
personally delivered; when receipt confirmed, if sent by facsimile; and the next
Business Day after timely  delivery to the courier,  if sent by an overnight air
courier service.

                  7.4  Entire  Agreement.  This  Agreement,  together  with  the
EXHIBITS  annexed hereto,  contains the entire  understanding  among the parties
hereto  concerning  the  subject  matter  hereof and this  Agreement  may not be
changed, modified, altered or terminated except by an

                                      -51-

<PAGE>



agreement in writing executed by the parties hereto.  Any waiver by any party of
any of its rights under this Agreement or of any breach of this Agreement  shall
not constitute a waiver of any other rights or of any other or future breach.

                  7.5  Remedies  Cumulative.  Except as  otherwise  provided  in
Section 6.5 hereof,  each and all of the rights and  remedies in this  Agreement
provided,  and each and all of the  rights  and  remedies  allowed at law and in
equity in like  case,  shall be  cumulative,  and the  exercise  of one right or
remedy  shall not be exclusive of the right to exercise or resort to any and all
other rights or remedies provided in this Agreement or at law or in equity.

                  7.6  Governing  Law.  This  Agreement  shall be  construed  in
accordance  with and subject to the laws and  decisions of the State of Delaware
applicable to contracts made and to be performed entirely therein.

                  7.7  Counterparts.  This  Agreement may be executed in several
counterparts   hereof,   and  by  the  different   parties  hereto  on  separate
counterparts  hereof, each of which shall be an original;  but such counterparts
shall together constitute one and the same instrument.

                  7.8 Waivers.  No provision in this  Agreement  shall be deemed
waived  except by an  instrument  in writing  signed by the party  waiving  such
provision.

                  7.9  Successors and Assigns.  This Agreement  shall be binding
upon and inure to the  benefit of the  parties  hereto  and to their  respective
permitted successors and assigns;  provided,  however, that, except as otherwise
expressly set forth in this Agreement, neither the rights nor the obligations of
any party may be assigned or delegated without the prior written consent of

                                      -52-

<PAGE>



the other  parties.  The  Investor  shall be  permitted to assign its rights and
obligations  under this Agreement to a wholly-owned  subsidiary of the Investor;
provided,  however,  that the Investor  shall  irrevocably  and  unconditionally
guarantee the  performance by such  subsidiary of all of the  obligations of the
Investor hereunder.

                  7.10 Further Assurances. The Investor shall, at the request of
a TDS Party,  and each of the TDS Parties shall, at the request of the Investor,
from time to time,  execute  and  deliver  such  other  assignments,  transfers,
conveyances  and other  instruments  and documents and do and perform such other
acts and  things as may be  reasonably  necessary  or  desirable  for  effecting
complete  consummation  of  this  Agreement  and the  transactions  contemplated
hereby.

                  7.11 Disclosures.  (a) Confidentiality.  The Investor and each
of the TDS Parties  acknowledges and confirms in connection with the negotiation
of this  Agreement  and the  execution  hereof,  during the period from the date
hereof  through the Closing Date,  the parties hereto will have furnished to one
another   certain   materials,   information,   data  and  other   documentation
("Disclosures")  concerning their business,  financial  condition and operations
which are proprietary and confidential. Each party acknowledges the party making
such   Disclosures   considers  them  secret  and  confidential  and  asserts  a
proprietary interest therein.  Accordingly,  the Investor,  on the one hand, and
each of the TDS Parties,  on the other hand,  covenants and agrees that it shall
maintain all  Disclosures  made by another party in strict  confidence and shall
not use such  Disclosures for its own benefit or disclose them to third parties,
except to its agents, representatives,  bankers, investment bankers, counsel and
employees involved in evaluating the transactions contemplated by this Agreement
and informed of this requirement of confidentiality, or as otherwise required by
law (including the requirement of TDS or Aerial to disclose such terms under the
federal  securities laws or under the rules of any securities  exchange on which
its securities are listed,  and including the requirement of the Investor or any
of

                                      -53-

<PAGE>



its  Affiliates to disclose such terms under the  securities  laws of Finland or
other applicable jurisdiction).

                  (b) Public  Announcements.  No public announcement with regard
to the  transactions  contemplated  hereby or the material terms hereof shall be
issued by any party hereto without the mutual prior written consent of the other
parties,  except to the extent  that the  parties are unable to agree on a press
release  and legal  counsel  for one  party is of the  opinion  that such  press
release is required by law.

                  (c)  Non-Confidential  Information.  This Agreement  shall not
restrict any party hereto from using  information  already known to it, to which
it is entitled under existing agreements, or information generally in the public
domain or any information coming into its possession received from a third party
with a right to possess or make disclosure thereof.

                  7.12  Termination.  (a) Events  Triggering  Termination.  This
Agreement  may be terminated  and the  transactions  contemplated  hereby may be
abandoned, without further obligation of the TDS Parties or the Investor, at any
time prior to the Closing Date as follows:

                  (i)      by mutual written consent duly authorized by the
boards of directors of the TDS Parties and the Investor; or

                  (ii) by any party  hereto if the  Closing  Date shall not have
occurred  on or before  December  31,  1998 or such later  date,  if any, as the
parties shall agree in writing,  provided,  that the party exercising such right
is not in default of its obligations under this Agreement in a manner which

                                      -54-

<PAGE>



results in the failure to satisfy the conditions to the transactions
contemplated hereby of the other parties; or

                  (iii)  by  any  party  hereto  if  the   consummation  of  the
transactions contemplated hereby shall be prohibited by a final,  non-appealable
order, decree or injunction of a court of competent jurisdiction,  or if the FCC
shall have by Final Order  denied the  application  for a Favorable  Declaratory
Ruling; or

                  (iv) by the TDS Parties in the event that the  Investor  shall
have  materially  breached any of its  representations,  warranties or covenants
contained in this Agreement; provided, however, that at the time and in the case
of a termination pursuant to this Section 7.12(a)(iv), no TDS Party is itself in
material  breach of its  representations,  warranties  and  covenants  contained
herein, and the TDS Parties (A) promptly notify the Investor in writing of their
intention to terminate this Agreement pursuant to this Section 7.12(a)(iv),  (B)
specify in such termination notice the  representation,  warranty or covenant of
which the Investor is allegedly in material  breach and (C) provide the Investor
with 30 days in which to cure such alleged breach or, if it cannot be cured,  to
fairly compensate the TDS Parties for such breach; or

                  (v) by the Investor in the event that any TDS Party shall have
materially  breached  any  of  its  representations,   warranties  or  covenants
contained in this Agreement; provided, however, that at the time and in the case
of a termination pursuant to this Section 7.12(a)(v), the Investor is not itself
in material breach of its  representations,  warranties and covenants  contained
herein, and the Investor (A) promptly notifies the TDS Parties in writing of its
intention to terminate this Agreement pursuant to this Section  7.12(a)(v),  (B)
specifies in such termination notice the representation, warranty or covenant of
which the TDS Party is allegedly in material breach and (C)

                                      -55-

<PAGE>



provides the TDS Parties  with 30 days in which to cure such alleged  breach or,
if it cannot be cured, to fairly compensate the Investor for such breach.

                  (b) No Further  Obligation.  In the event of a termination  of
this Agreement,  no party hereto shall have any liability or further  obligation
to any other party to this Agreement except that nothing herein will relieve any
party from liability for any breach of this Agreement.

                  7.13 No Claim of Immunity.  The Investor  agrees that,  to the
extent  that it or any of its  property,  its  Affiliates,  or  property  of its
Affiliates is or becomes entitled at any time to any immunity, on the grounds of
sovereignty or otherwise,  based upon its status as an agency or instrumentality
of  government,  from any legal  action,  suit or  proceeding  or from setoff or
counterclaim  relating to this Agreement from the  jurisdiction of any competent
court,  from  service  of  process,  from  attachment  prior to  judgment,  from
attachment  in aid of  execution  of a judgment,  from  execution  pursuant to a
judgement  or  arbitration  award,  or  from  any  other  legal  process  in any
jurisdiction,  it, for itself,  its  Affiliates,  its  property  and that of its
Affiliates,  expressly,  irrevocably and unconditionally  agrees not to plead or
claim,  any such immunity  with respect to such matters  arising with respect to
this  Agreement or the subject  matter hereof  (including any obligation for the
payment of money).

                  7.14  Severability.   In  the  event  any  provision  of  this
Agreement  is found to be  invalid  or  unenforceable  in whole or in part,  the
remaining  provisions of this  Agreement  nevertheless  shall be binding and the
invalid or unenforceable  provision shall be replaced by a valid and enforceable
provision  which comes closest to the intent or economic effect of the provision
to be replaced.



                                      -56-

<PAGE>



                                    ARTICLE 8

                                    DISPUTES

                  8.1  General.  The  parties  agree to  resolve  disagreements,
disputes  and  controversies  between  them  arising  out of or  related to this
Agreement or the breach thereof through the procedures set forth in this Article
8.

                  8.2  Negotiation  Procedure.  (a) The TDS Parties,  on the one
hand, and the Investor,  on the other hand, shall designate one or more officers
who will be the initial  contact for resolving any disputes that may arise under
this  Agreement.  The TDS  Parties and the  Investor  shall first raise any such
disputes with a designated  officer of the other party. These officers will work
together  to  resolve  the  disputes  so  referred  in a manner  that  meets the
interests of both the TDS Parties and the Investor,  either until such agreement
is  reached,  or until an impasse is  declared  by either the TDS Parties or the
Investor; provided, however, that an impasse shall not be declared by either the
TDS Parties or the Investor  prior to the  thirtieth  day after such dispute has
first been referred to such  designated  officers.  Notice of declaration of any
impasse shall be given in accordance with Section 7.3 hereof.

                  (b) The officers  initially  designated by the TDS Parties and
the Investor  for purposes of this Section 8.2 are set forth in Schedule  8.2(b)
to this Agreement.  Parties may change such designation by giving notice of such
change pursuant to Section 7.3 hereof.

                  (c) Any  resolution  of a dispute by the  designated  officers
pursuant to Section  8.2(b) hereof shall be in writing signed by such persons on
behalf of the parties. Notwithstanding any

                                      -57-

<PAGE>



provision  of this  Article 8, no  resolution  of any dispute by any  designated
officer shall constitute an amendment of this Agreement  without the approval of
the respective boards of directors of each party hereto.

                  8.3  Unresolved  Disputes.  The  parties  shall be entitled to
exercise or resort to any and all rights and remedies provided in this Agreement
or at law or in equity with  respect to any  controversy  or claim not  resolved
through the procedures set forth above.

                  8.4  Jurisdiction;  Consent to Service  of  Process.  (a) Each
party hereby irrevocably  consents and submits to the jurisdiction of the United
States District Court for the District of Delaware and any court of the State of
Delaware in any action,  suit or proceeding  arising out of,  resulting  from or
relating to this Agreement,  and agrees that any such action, suit or proceeding
shall be brought  only in such courts (and waives any  objection  based on forum
non conveniens or any other objection to venue therein); provided, however, that
such  consent to  jurisdiction  is solely for the  purpose  referred  to in this
Section  8.4  and  shall  not  be  deemed  to be a  general  submission  to  the
jurisdiction  of said  courts  or the  State  of  Delaware  other  than for such
purpose.

                  (b) The Investor hereby  irrevocably  appoints The Corporation
Trust Company, at its office at 1209 Orange Street, Wilmington, Delaware, United
States of  America,  its lawful  agent and  attorney  to accept and  acknowledge
service of any and all  process  against it in any  action,  suit or  proceeding
arising out of, resulting from or relating to this Agreement, and upon whom such
process  may be served,  with the same  effect as if it were a  resident  of the
State of  Delaware,  and had been  lawfully  served  with such  process  in such
jurisdiction,  and waives all claim of error by reason of such service, provided
that in the case of any service  upon such agent and  attorney,  the TDS Parties
shall also  deliver a copy  thereof to the  Investor  at the  address and in the
manner

                                      -58-

<PAGE>



specified  in Section  7.3  hereof.  In the event  that such agent and  attorney
resigns or  otherwise  becomes  incapable of acting as such,  the Investor  will
appoint a successor  agent and  attorney  in  Wilmington,  Delaware,  reasonably
satisfactory  to the TDS Parties,  with like powers or, if the Investor fails to
make such appointment, the Investor hereby authorizes the TDS Parties to appoint
such agent.  The  Investor  shall pay the annual fee due The  Corporation  Trust
Company or such successor agent for acting in such capacity;  provided, however,
that if the Investor shall fail to make such payment, then the TDS Parties shall
have the right to do so.

                                    * * * * *

                                      -59-

<PAGE>




                  IN WITNESS WHEREOF, the parties hereto have duly executed this
Agreement as of the date first above written.

                        TELEPHONE AND DATA SYSTEMS, INC.

                       By:_______________________________

                       Name:_____________________________

                       Title:____________________________

                                   AERIAL COMMUNICATIONS, INC.

                       By:_______________________________

                       Name:_____________________________

                       Title:____________________________

                                   APT OPERATING CO., INC.

                       By:_______________________________

                       Name:_____________________________

                       Title:____________________________

                                   SONERA CORPORATION

                       By:_______________________________

                       Name:_____________________________

                       Title:____________________________





         SIGNATURE PAGE TO PURCHASE AGREEMENT DATED AS OF JUNE ___, 1998



                                      -60-

<PAGE>



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