Systems and methods for wireless communication system channel allocation using intentional delay distortion

1. A method for enhancing capacity in an orthogonal frequency division multiple access (OFDMA) wireless system, said method comprising:

intentionally creating a multi-path distortion in signals broadcast from a base station in an otherwise flat fading environment;

allocating a first plurality of subcarriers to a first subscriber station and a second plurality of subcarriers to a second subscriber station based upon a determination of diversity gains of said first and second subscriber stations, said determination being based, at least in part, on said intentionally created multi-path distortion;

receiving a notification that a retraining is needed for said first subscriber station based on a measured channel deterioration for said first subscriber station; and

after said receiving said notification:

broadcasting new signals with a new intentionally created multi-path distortion;

redetermining said diversity gains of at least said first subscriber station; and

allocating a new first plurality of subcarriers to said first subscriber station based on said redetermined diversity gains, at least one subcarrier of said new first plurality of subcarriers being different from at least one subcarrier of said first plurality of subcarriers.

2. The method of claim 1 , wherein said intentionally created multi-path distortion is created by broadcasting a signal and at least one time-delayed version of said broadcast signal.

3. The method of claim 2 , wherein said diversity gains are determined by resolving said intentionally created multi-path distortion created by said at least one time-delayed version of said broadcast signal.

4. The method of claim 2 , wherein said base station utilizes orthogonal frequency division multiplexing (OFDM).

5. The method of claim 4 , wherein said broadcast signal comprises pilot OFDM symbols.

6. The method of claim 2 , wherein said at least one time-delayed version of said broadcast signal is broadcast according to a pattern.

7. The method of claim 6 , wherein said pattern changes over time.

8. The method of claim 1 , further comprising:

notifying said first subscriber station and said second subscriber station of results of said allocating, wherein said notifying uses at least one downlink common control channel.

9. A method for enhancing multi-user diversity in an orthogonal frequency division multiple access (OFDMA) wireless system, said method comprising:

selecting a first plurality of subcarriers for a first subscriber station upon a determination of a diversity gain of said first subscriber station, said first subscriber station diversity gain determination based on an intentional multi-path distortion created by transmission of a first pilot signal and a time-delayed version of said first pilot signal from a base station;

selecting a second plurality of subcarriers for a second subscriber station upon a determination of a diversity gain of said second subscriber station, said second subscriber station diversity gain determination based on said created intentional multi-path distortion;

allocating a communication channel to said first subscriber station based, at least in part, on said selection of said first plurality of subcarriers;

allocating a different communication channel to said second subscriber station based, at least in part, on said selection of said second plurality of subcarriers;

receiving a notification that a retraining is needed for said first subscriber station based on a measured channel deterioration; and

after said receiving said notification, selecting a new first plurality of subcarriers for said first subscriber station based upon a newly determined diversity gain of said first subscriber station, said newly determined diversity gain based on a new intentional multi-path distortion created by transmission of a new pilot signal and at least one time-delayed version of said new pilot signal from said base station, and at least one subcarrier of said new first plurality of subcarriers being different from at least one subcarrier of said first plurality of subcarriers.

10. The method of claim 9 , further comprising:

determining if said retraining is necessary for said first subscriber station; and

if said retraining is necessary, re-allocating another communication channel to said first subscriber station to compensate for movement of said first subscriber station.

11. The method of claim 9 , wherein said allocating said different communication channel is based, at least in part, on said allocating said communication channel.

12. The method of claim 11 , wherein said allocating said different communication channel is performed when said second subscriber station is added to said OFDMA wireless system.

13. A subscriber station in a wireless system, said subscriber station comprising:

an orthogonal frequency division modulation (OFDM) demodulator configured to:

receive a signal and an intentionally delayed version of said signal, where said intentionally delayed version of said signal intentionally creates multi-user diversity in said wireless system;

send a selection of at least one channel to a base station; and

receive an allocation of a channel based, at least in part, on said sent selection of said at least one channel; and

a processor configured to:

resolve multi-path distortion created by said received intentionally delayed version of said signal to determine a diversity gain of said subscriber station; and

select said at least one channel based on said determined diversity gain of said subscriber station.

14. The subscriber station of claim 13 , wherein said processor is further configured to:

update said selection of said at least one channel, performed periodically to compensate for movement of said subscriber station within said wireless system.

15. The subscriber station of claim 13 , wherein said processor is further configured to:

update said selection of said at least one channel, performed periodically to compensate for changes in said determined diversity gain of said subscriber station.

16. A method for enhancing multi-user diversity in an orthogonal frequency division multiple access (OFDMA) wireless system, said method comprising:

selecting a first plurality of subchannels for a first subscriber station based upon a first determination of diversity gain based on a intentional multi-path distortion of a signal broadcast from a base station in an otherwise flat-fading environment;

selecting a second plurality of subchannels for a second subscriber station based upon a second determination of diversity gain based on said intentional multi-path distortion of said broadcast signal;

allocating one or more subcarriers to a plurality of subscriber stations in an OFDMA network based on said first and second determined diversity gains, wherein said first and second determined diversity gains are obtained by resolving said intentional multi-path distortion;

receiving a notification that retraining is needed for said first subscriber station based on a measured channel deterioration; and

after said receiving said notification, selecting a new first plurality of subchannels for said first subscriber station based upon a new determination of diversity gain based on a new intentional multi-path distortion of a new signal broadcast from said base station, at least one subchannel of said new first plurality of subchannels being different from at least one subchannel of said first plurality of subchannels.

17. The method of claim 16 , wherein said allocating further comprises a dynamic resource allocation scheme, said dynamic resource allocation scheme comprising assigning a particular subcarrier to said plurality of subscriber stations based on said obtained first and second determined diversity gains.

18. The method of claim 16 , further comprising:

from time to time modifying a channel allocation between said base station and one or more subscriber stations of said plurality of subscriber stations to optimize network capacity.

19. The method of claim 16 , wherein said intentional multi-path distortion is created by broadcasting a pilot signal and at least one time-delayed version of said pilot signal.

20. A subscriber station within a wireless system, said subscriber station comprising:

an orthogonal frequency division modulation (OFDM) demodulator configured to:

receive a signal and an intentionally delayed version of said signal, where said intentionally delayed version of said signal intentionally creates multi-user diversity in said wireless system; and

receive allocation of a channel, wherein said channel allocation is based, at least in part, on a selection of at least one channel; and

a processor configured to:

resolve multi-path distortion created by said received intentionally delayed version of said signal to determine a diversity gain of said subscriber station;

select said at least one channel based on said determined diversity gain of said subscriber station; and

update said selection of said at least one channel, said updating being performed periodically to compensate for changes in said determined diversity gain of said subscriber station.