<PAGE>   1
                                                                Exhibit 3(ii)(a)

                               POWERTEL USA, INC.

                           AMENDED AND RESTATED BYLAWS


                            ARTICLE I - STOCKHOLDERS


                  SECTION 1.  ANNUAL MEETING.

                  An annual meeting of the stockholders, for the election of
directors to succeed those whose terms expire and for the transaction of such
other business as may properly come before the meeting, shall be held at such
place, on such date, and at such time as the Board of Directors shall each year
fix, which date shall be within thirteen months subsequent to the later of the
date of incorporation or the last annual meeting of stockholders.

                  SECTION 2.  SPECIAL MEETINGS.

                  Special meetings of the stockholders, for any purpose or
purposes prescribed in the notice of the meeting, may be called by the Board of
Directors or the chief executive officer and shall be held at such place, on
such date, and at such time as the persons or person calling the special
meeting shall fix.

                  SECTION 3.  NOTICE OF MEETINGS.

                  Written notice of the place, date and time of all meetings of
the stockholders shall be given, not less than ten nor more than sixty days
before the date on which the meeting is to be held, to each stockholder entitled
to vote at such meeting, except as otherwise provided herein or required by law
(meaning, here and hereinafter, as required from time to time by the Delaware
General Corporation Law or the Certificate of Incorporation of the corporation).

                  When a meeting is adjourned to another place, date or time,
written notice need not be given of the adjourned meeting if the place, date and
time thereof are announced at the meeting at which the adjournment is taken;
provided, however, that if the date of any adjourned meeting is more than thirty
days after the date
<PAGE>   2
for which the meeting was originally noticed, or if a new record date is fixed
for the adjourned meeting, written notice of the place, date and time of the
adjourned meeting shall be given in conformity herewith. At any adjourned
meeting, any business may be transacted which might have been transacted at the
original meeting.


                  SECTION 4.  QUORUM.

                  At any meeting of the stockholders, the holders of a majority
of all of the shares of the stock entitled to vote at the meeting, present in
person or by proxy, shall constitute a quorum for all purposes, unless or except
to the extent that the presence of a larger number may be required by law.

                  If a quorum shall fail to attend any meeting, the chairman of
the meeting or the holders of a majority of the shares of the stock entitled to
vote who are present, in person or by proxy, may adjourn the meeting to another
place, date, or time.

                  If a notice of any adjourned special meeting of stockholders
is sent to all stockholders entitled to vote thereat, stating that it will be
held with those present constituting a quorum, then except as otherwise required
by law, those present at such adjourned meeting shall constitute a quorum, and
all matters shall be determined by a majority of the votes cast at such meeting.

                  SECTION 5.  ORGANIZATION.

                  Such person as the Board of Directors may have designated or,
in the absence of such a person, the chief executive officer of the corporation
or, in his absence, such person as may be chosen by the holders of a majority of
the shares entitled to vote who are present, in person or by proxy, shall call
to order any meeting of the stockholders and act as chairman of the meeting. In
the absence of the Secretary of the corporation, the secretary of the meeting
shall be such person as the chairman appoints.

                  SECTION 6.  CONDUCT OF BUSINESS.

                  The chairman of any meeting of stockholders shall
<PAGE>   3
determine the order of business and the procedure at the meeting, including such
regulation of the manner of voting and the conduct of discussion as seem to the
chairman in order.

                  SECTION 7.  PROXIES AND VOTING.

                  At any meeting of the stockholders, every stockholder entitled
to vote may vote in person or by proxy authorized by an instrument in writing
filed in accordance with the procedure established for the meeting.

                  Each stockholder shall have one vote for every share of stock
entitled to vote which is registered in such stockholder's name on the record
date for the meeting, except as otherwise provided herein or required by law.

                  All voting, including on the election of directors, but
excepting where otherwise required by law, may be by a voice vote; provided,
however, that upon demand therefor by a stockholder (or a person acting as proxy
for a stockholder) entitled to vote, a stock vote shall be taken. Every stock
vote shall be taken by ballot. Each ballot shall state the name of the
stockholder or proxy voting and such other information as may be required under
the procedure established for the meeting. Every vote taken by ballot shall be
counted by an inspector or inspectors appointed by the chairman of the meeting.

                  All elections shall be determined by a plurality of the votes
cast, and except as otherwise required by law, all other matters shall be
determined by a majority of the votes cast.

                  SECTION 8.  STOCK LIST.

                  A complete list of stockholders entitled to vote at any
meeting of stockholders, arranged in alphabetical order for each class of stock
and showing the address of each such stockholder and the number of shares
registered in such stockholder's name, shall be open to the examination of any
such stockholder, for any purpose germane to the meeting, during ordinary
business hours for a period of at least ten (10) days prior to the meeting,
either at a place within the city where the meeting is to be held, which place
shall be specified in the notice of the meeting, or if not so specified, at the
place where the meeting is to be held.
<PAGE>   4
                  The stock list shall also be kept at the place of the meeting
during the whole time thereof and shall be open to the examination of any such
stockholder who is present. This list shall presumptively determine the identity
of the stockholders entitled to vote at the meeting and the number of shares
held by each of them.

                  SECTION 9.  CONSENT OF STOCKHOLDERS IN LIEU OF MEETING.

                  Any action required to be taken at any annual or special
meeting of stockholders of the corporation, or any action which may be taken at
any annual or special meeting of the stockholders, may be taken without a
meeting, without prior notice and without a vote, if a consent in writing,
setting forth the action so taken, shall be signed by the holders of outstanding
stock having not less than the minimum number of votes that would be necessary
to authorize or take such action at a meeting at which all shares entitled to
vote thereon were present and voted and shall be delivered to the corporation by
delivery to its registered office in the State of Delaware, its principal place
of business, or an officer or agent of the corporation having custody of the
book in which proceedings of meetings of stockholders are recorded. Delivery to
the corporation's registered office shall be by hand or by certified or
registered mail, return receipt requested. Every written consent shall bear the
date of signature of each stockholder who signs the consent.
<PAGE>   5
                         ARTICLE II - BOARD OF DIRECTORS

                  SECTION 1.  NUMBER AND TERM OF OFFICE.

                  The number of directors who shall constitute the whole board
shall be such number as the Board of Directors shall at the time have
designated, except that in the absence of any such designation, such number
shall be three (3). A director whose term has expired and whose directorship has
not been eliminated by a decrease in the number of directors effective upon the
expiration of the director's term shall continue in office until such director's
successor is elected and qualified, except as otherwise provided herein or
required by law.

                  SECTION 2.  REGULAR MEETINGS.

                  Regular meetings of the Board of Directors shall be held at
such place or places, on such date or dates, and at such time or times as shall
have been established by the Board of Directors and publicized in writing among
all directors. A separate written notice of each regular meeting shall not be
required.

                  SECTION 3.  SPECIAL MEETINGS.

                  Special meetings of the Board of Directors may be called by
one-third of the directors then in office (rounded up to the nearest whole
number) or by the chief executive officer and shall be held at such place, on
such date, and at such time as the person or persons calling the special meeting
shall fix. Notice of the place, date, and time of each such special meeting
shall be given each director by whom it is not waived by mailing written notice
not less than five days before the meeting or by providing written notice by
facsimile or other means of electronic transmission the same not less than
twenty-four hours before the meeting. Unless otherwise indicated in the notice
thereof, any and all business may be transacted at a special meeting.

                  SECTION 4.  QUORUM.

                  At any meeting of the Board of Directors, a majority of the
total number of the whole board shall constitute a quorum for all purposes. If a
quorum shall fail to attend any meeting, a majority of those present may adjourn
the meeting to any place,
<PAGE>   6
date, or time, without further notice or waiver thereof.

                  SECTION 5.  PARTICIPATION IN MEETINGS BY CONFERENCE TELEPHONE.

                  Members of the Board of Directors, or of any committee
thereof, may participate in a meeting of such board or committee by means of
conference telephone or similar communications equipment by means of which all
persons participating in the meeting can hear each other and such participation
shall constitute presence in person at such meeting.

                  SECTION 6.  CONDUCT OF BUSINESS.

                  At any meeting of the Board of Directors, business shall be
transacted in such order and manner as the board may from time to time
determine, and all matters shall be determined by the vote of a majority of the
directors present, except as otherwise provided herein or required by law.
Action may be taken by the Board of Directors without a meeting if all members
thereof consent thereto in writing, and the writing or writings are filed with
the minutes of proceedings of the Board of Directors.

                  SECTION 7.  POWERS.

                  The Board of Directors may, except as otherwise required by
law, exercise all such powers and do all such acts and things as may be
exercised or done by the corporation.

                  SECTION 8.  COMPENSATION OF DIRECTORS.

                  Directors shall receive fees or other compensation for their
services as directors, including, without limitation, their services as members
of committees of the Board of Directors. Directors may be reimbursed for actual
out-of-pocket expenses incurred by them in the performance of their duties as
directors.

                  SECTION 9.  INDEMNIFICATION OF OFFICERS AND DIRECTORS.

                  Every person who was or is a party or is threatened to be made
a party to or is involved in any action, suit or proceeding, whether civil,
criminal, administrative or investigative, by reason of the fact that such
person, or a person of whom such person is the legal representative, is or was a
director or officer of the
<PAGE>   7
corporation or is or was serving at the request of the corporation as a director
or officer of another corporation, or as its representative in a partnership,
joint venture, trust or other enterprise, whether the basis of such action, suit
or proceeding is any alleged action in an official capacity as director, officer
or representative, or in any other capacity while serving as a director, officer
or representative, shall be indemnified and held harmless by the corporation to
the fullest extent authorized by the General Corporation Law of the State of
Delaware, as the same exists or may hereafter be amended, against all expenses,
liability and loss (including attorneys' fees, judgments, fines, ERISA excise
taxes or penalties and amounts paid or to be paid in settlement) reasonably
incurred or suffered by such person in connection therewith; provided, however,
that the corporation shall indemnify any such person in connection with any
action, suit or proceeding (or part thereof) initiated by such person only if
such action, suit or proceeding (or part thereof) was authorized by the Board of
Directors of the corporation. Such right shall be a contract right and shall
include the right to be paid by the corporation expenses incurred in defending
any action, suit or proceeding in advance of its final disposition upon delivery
to the corporation of an undertaking, by or on behalf of such person, to repay
all amounts so advanced unless it should be determined ultimately that such
person is entitled to be indemnified under this Section 9 or otherwise.

                  The rights conferred by this Section 9 shall not be exclusive
of any other right to indemnification or advancement of expenses which a person
may have or hereafter acquire under any statute, provision of the certificate of
incorporation, bylaw, agreement, vote of stockholders or disinterested directors
or otherwise.
<PAGE>   8
                            ARTICLE III - COMMITTEES

                  SECTION 1.  COMMITTEES OF THE BOARD OF DIRECTORS.

                  The Board of Director may from time to time designate
committees of the board, with such lawfully delegable powers and duties as it
thereby confers, to serve at the pleasure of the board and shall, for those
committees and any others provided for herein, elect a director or directors to
serve as the member or members, designating, if it desires, other directors as
alternate members who may replace any absent or disqualified member at any
meeting of the committee. In the absence or disqualification of any member of
any committee and any alternate member in his place, the member or members of
the committee present at the meeting and not disqualified from voting, whether
or not he or they constitute a quorum, may by unanimous vote appoint another
member of the Board of Directors to act at the meeting in the place of the
absent or disqualified member.

                  SECTION 2.  CONDUCT OF BUSINESS.

                  Each committee may determine the procedural rules for meeting
and conducting its business and shall act in accordance therewith, except as
otherwise provided herein or required by law. Adequate provision shall be made
for notice to members of all meetings; one-third of the members shall constitute
a quorum unless the committee shall consist of one or two members, in which
event one member shall constitute a quorum; and all matters shall be determined
by a majority vote of the members present. Action may be taken by any committee
without a meeting if all members thereof consent thereto in writing, and the
writing or writings are filed with the minutes of the proceedings of such
committee.
<PAGE>   9
                              ARTICLE IV - OFFICERS

                  SECTION 1.  GENERALLY.

                  The officers of the corporation shall consist of a president,
a secretary, a treasurer and such other officers as may from time to time be
appointed by the Board of Directors. Officers shall be elected by the Board of
Directors which shall consider that subject at its first meeting after every
annual meeting of stockholders. Each officer shall hold office until his or her
successor is elected and qualified or until his or her earlier resignation or
removal. The president shall be a member of the Board of Directors. Any number
of offices may be held by the same person.

                  SECTION 2.  PRESIDENT.

                  The president shall be the chief executive officer of the
corporation. Subject to the provisions of these bylaws and to the direction of
the Board of Directors, the president shall have the responsibility for the
general management and control of the business and affairs of the corporation
and shall perform all duties and have all powers which are commonly incident to
the office of chief executive or which are delegated to him by the Board of
Directors. The president shall have power to sign all stock certificates,
contracts and other instruments of the corporation which are authorized and
shall have general supervision and direction of all of the other officers,
employees and agents of the corporation.

                  SECTION 3.  VICE PRESIDENT.

                  Each vice president, to the extent that there are any, shall
have such powers and duties as may be delegated to him or her by the Board of
Directors. One vice president shall be designated by the board to perform the
duties and exercise the powers of the president in the event of the president's
absence or disability.

                  SECTION 4.  TREASURER.

                  The treasurer shall have the responsibility for
maintaining the financial records of the corporation and shall have
custody of all monies and securities of the corporation.  The
<PAGE>   10
treasurer shall make such disbursements of the funds of the corporation as are
authorized and shall render from time to time an account of all such
transactions and of the financial condition of the corporation. The treasurer
shall also perform such other duties as the Board of Directors may from time to
time prescribe.

                  SECTION 5.  SECRETARY.

                  The secretary shall issue all authorized notices for, and
shall keep minutes of, all meetings of the stockholders and the Board of
Directors. The secretary shall have charge of the corporate books and shall
perform such other duties as the Board of Directors may from time to time
prescribe.


                  SECTION 6.  DELEGATION OF AUTHORITY.

                  The Board of Directors may from time to time delegate the
powers or duties of any officer to any other officer or agent, notwithstanding
any other provision of these bylaws.

                  SECTION 7.  REMOVAL.

                  Any officer of the corporation may be removed at any time,
with or without cause, by the Board of Directors.

                  SECTION 8.  ACTION WITH RESPECT TO SECURITIES OF OTHER 
                              CORPORATIONS.

                  Unless otherwise directed by the Board of Directors, the
president shall have power to vote and otherwise act on behalf of the
corporation, in person or by proxy, at any meeting of stockholders of or with
respect to any action of stockholders of any other corporation in which this
corporation may hold securities and otherwise to exercise any and all rights and
powers which this corporation may possess by reason of its ownership of
securities in such other corporation.
<PAGE>   11
                                ARTICLE V - STOCK

                  SECTION 1.  CERTIFICATES OF STOCK.

                  Each stockholder shall be entitled to a certificate signed by,
or in the name of the corporation by, the president or a vice president, and by
the secretary or an assistant secretary, or the treasurer or an assistant
treasurer, certifying the number of shares owned by such stockholder. Any of or
all the signatures on the certificate may be facsimile.

                  SECTION 2.  TRANSFERS OF STOCK.

                  Transfers of stock shall be made only upon the transfer books
of the corporation kept at an office of the corporation or by transfer agents
designated to transfer shares of the stock of the corporation. Except where a
certificate is issued in accordance with Section 4 of Article V of these bylaws,
an outstanding certificate for the number of shares involved shall be
surrendered for cancellation before a new certificate is issued therefor.

                  SECTION 3.  RECORD DATE.

                  In order that the corporation may determine the stockholders
entitled to notice of or to vote at any meeting of stockholders or any
adjournment thereof, the Board of Directors may fix a record date, which record
date shall not precede the date upon which the resolution fixing the record date
is adopted by the Board of Directors, and which record date shall not be more
than sixty nor less than ten days before the date of such meeting.

                  In order that the corporation may determine the stockholders
entitled to consent to corporate action in writing without a meeting, the Board
of Directors may fix a record date, which record date shall not precede the date
upon which the resolution fixing the record date is adopted by the Board of
Directors, and which date shall not be more than ten days after the date upon
which the resolution fixing the record date is adopted by the Board of
Directors.
<PAGE>   12
                  In order that the corporation may determine the stockholders
entitled to receive payment of any dividend or other distribution or allotment
of any rights or the stockholders entitled to exercise any rights in respect of
any change, conversion or exchange of stock, or for the purpose of any other
lawful action, the Board of Directors may fix a record date, which record date
shall not precede the date upon which the resolution fixing the record date is
adopted, and which record date shall be not more than sixty days prior to such
action.

                  SECTION 4.  LOST, STOLEN OR DESTROYED CERTIFICATES.

                  In the event of the loss, theft or destruction of any
certificate of stock, another may be issued in its place pursuant to such
regulations as the Board of Directors may establish (or in the absence of such
regulations, pursuant to a resolution adopted by the Board of Directors)
concerning proof of such loss, theft or destruction and concerning the giving of
a satisfactory bond or bonds of indemnity.

                  SECTION 5.  REGULATIONS.

                  The issue, transfer, conversion and registration of
certificates of stock shall be governed by such other regulations as the Board
of Directors may by resolution establish from time to time.
<PAGE>   13
                              ARTICLE VI - NOTICES

                  SECTION 1.  NOTICES.

                  Except as otherwise specifically provided herein or required
by law, all notices required by these bylaws to be given to any stockholder,
director, officer, employee or agent, shall be in writing and may in every
instance be effectively given by hand delivery to the recipient thereof, by
depositing such notice in the mails, postage paid, by sending such notice by
prepaid telegram or mailgram, or by sending such notice by Federal Express or
other similar private carrier providing evidence of delivery. Any such notice
shall be addressed to such stockholder, director, officer, employee, or agent at
his or her last known address as the same appears on the books of the
corporation. The time when such notice is received, if hand delivered, or
dispatched, if delivered through the mails, by telegram or mailgram or by
private carrier, shall be the time of the giving of the notice.

                  SECTION 2.  WAIVERS.

                  A written waiver of any notice, signed by a stockholder,
director, officer, employee or agent, whether before or after the time of the
event for which notice is to be given, shall be deemed equivalent to the notice
required to be given to such stockholder, director, officer, employee or agent.
Neither the business nor the purpose of any meeting need be specified in such a
waiver.
<PAGE>   14
                           ARTICLE VII - MISCELLANEOUS

                  SECTION 1.  FACSIMILE SIGNATURES.

                  In addition to the provisions for use of facsimile signatures
elsewhere specifically authorized in these bylaws, facsimile signatures of any
officer or officers of the corporation may be used whenever and as authorized by
the Board of Directors or a committee thereof.

                  SECTION 2.  CORPORATE SEAL.

                  The Board of Directors may approve and adopt a suitable seal,
containing the name of the corporation, which seal shall be in the charge of the
secretary. If and when so directed by the Board of Directors or a committee
thereof, duplicates of the seal may be kept and used by the treasurer or by an
assistant secretary or assistant treasurer.

                  SECTION 3.  RELIANCE UPON BOOKS, REPORTS AND RECORDS.

                  Each director, each member of any committee designated by the
Board of Directors, and each officer of the corporation shall, in the
performance of his or her duties, be fully protected in relying in good faith
upon the books of account or other records of the corporation, and upon such
information, opinions, reports and statements made to the corporation by any of
its officers, employees, or committees of the board of directors, or by any
other person as to matters reasonably believed to be within such other person's
professional or expert competence and who has been selected with reasonable care
by or on behalf of the corporation.

                  SECTION 4.  FISCAL YEAR.

                  The fiscal year of the corporation shall be as fixed by the
Board of Directors.
<PAGE>   15
                  SECTION 5.  TIME PERIODS.

                  In applying any provision of these bylaws which requires that
an act be done or not done a specified number of days prior to an event or that
an act be done during a period of a specified number of days prior to an event,
calendar days shall be used, the day of the doing of the act shall be excluded,
and the day of the event shall be included.
<PAGE>   16
                            ARTICLE VIII - AMENDMENTS

                  SECTION 1.  AMENDMENTS.

                  These bylaws may be amended or repealed by the Board of
Directors at any meeting or by the affirmative vote of 65% or more of the
outstanding shares of capital stock of the corporation entitled to vote at any
meeting.