Power control and overlapping control for a quasi-orthogonal communication system

• US 20060211441A1
• Filed: 06/21/2005
• Published: 09/21/2006
• Est. Priority Date: 03/15/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Naguib, Ayman Fawzy, Gorokhov, Alexei, Sutivong, Arak, Ji, Tingfang, Mese, Murat, Gore, Dhananjay
• Granted Patent: US 7,512,412 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading

Abstract

Techniques for controlling transmit power and the amount of overlapping in a quasi-orthogonal system are described. A base station for a sector receives transmissions from terminals in that sector and neighbor sectors and determines performance metrics (e.g., overall throughput) and/or QoS metrics (e.g., minimum data rate) for the terminals in the sector. The base station updates an overlapping factor based on the performance metrics and updates a QoS power control parameter based on the QoS metrics. The overlapping factor indicates the average number of overlapping transmissions sent simultaneously on each time-frequency block usable for data transmission. The QoS power control parameter ensures that the terminals in the sector can achieve minimum QoS requirements. A power control mechanism with multiple loops is used to adjust the transmit power of each terminal. The overlapping factor and QoS power control parameter are updated by two of the loops.

Claims

1. An apparatus comprising:

a processor operative to provide information used to adjust an overlapping factor indicative of an average number of overlapping transmissions; and

a controller operative to update the overlapping factor based on the information from the processor.

2. The apparatus of claim 1, wherein the controller is operative to determine at least one performance metric and to update the overlapping factor based on the at least one performance metric.

3. The apparatus of claim 1, wherein the processor is operative to provide status of received packets, and wherein the controller is operative to determine an overall throughput based on the status of the received packets from the processor and to update the overlapping factor based on the overall throughput.

4. The apparatus of claim 1, wherein the controller is operative to determine at least one quality of service (QoS) metric and to update the overlapping factor based on the at least one QoS metric.

5. The apparatus of claim 1, wherein the processor is operative to perform receiver spatial processing to separate overlapping transmissions and to provide results of the receiver spatial processing, and wherein the controller is operative to adjust the overlapping factor based on the results of the receiver spatial processing.

6. The apparatus of claim 1, wherein the processor is operative to estimate interference observed b and to provide an interference estimate, and wherein the controller is operative to adjust the overlapping factor based on the interference estimate.

7. The apparatus of claim 1, further comprising:

a scheduler operative to schedule terminals for data transmission based on the overlapping factor.

8. The apparatus of claim 7, wherein the scheduler is operative to assign the scheduled terminals to a plurality of channel sets each consisting of traffic channels, and wherein traffic channels in each channel set are orthogonal to one another and are pseudo-random with respect to traffic channels in each remaining channel set.

9. The apparatus of claim 7, wherein the scheduler is operative to assign the scheduled terminals with traffic channels in a minimum number of channel sets.

10. The apparatus of claim 1, wherein the processor is operative to provide information for each of a plurality of frequency subbands, and wherein the controller is operative to maintain and update an overlapping factor for each frequency subband based on the information for the frequency subband.

11. The apparatus of claim 10, wherein the plurality of frequency subbands are formed with orthogonal frequency division multiplexing (OFDM).

12. A method of controlling data transmission, comprising:

obtaining information used to adjust an overlapping factor indicative of an average number of overlapping transmissions; and

updating the overlapping factor based on the obtained information.

13. The method of claim 12, further comprising:

determining at least one performance metric based on the obtained information, and wherein the updating the overlapping factor comprises updating the overlapping factor based on the at least one performance metric.

14. The method of claim 12, further comprising:

scheduling terminals for data transmission based on the overlapping factor.

15. The method of claim 12, wherein the average number of overlapping transmissions corresponds to an average number of terminals assigned to a same group of channel sets.

16. An apparatus comprising:

means for obtaining information used to adjust an overlapping factor indicative of an average number of overlapping transmissions; and

means for updating the overlapping factor based on the obtained information.

17. The apparatus of claim 16, further comprising:

means for determining at least one performance metric based on the obtained information, and wherein the means for updating the overlapping factor comprises means for updating the overlapping factor based on the at least one performance metric.

18. The apparatus of claim 16, further comprising:

means for scheduling terminals for data transmission based on the overlapping factor.

19. The apparatus of claim 16, wherein the average number of overlapping transmissions corresponds to an average number of terminals assigned to a same group of channel sets.

20. An apparatus comprising:

a processor operative to obtain an overlapping factor, the overlapping factor being indicative of an average number of overlapping transmissions; and

a controller operative to determine transmit power for a data transmission based on the overlapping factor.

21. The apparatus of claim 20, wherein the processor is operative to detect a transmit power control (TPC) command from the base station and to provide a TPC decision, and wherein the controller is operative to determine the transmit power for the data transmission further based on the TPC decision.

22. The apparatus of claim 21, wherein the controller is operative to adjust a reference power level based on the TPC decision and to determine the transmit power for the data transmission based on the reference power level.

23. The apparatus of claim 20, wherein the processor is operative to obtain at least one indication of interference, and wherein the controller is operative to determine the transmit power for the data transmission further based on the at least one indication of interference.

24. The apparatus of claim 23, wherein the controller is operative to adjust a transmit power delta based on the at least one indication of interference and to determine the transmit power for the data transmission further based on the transmit power delta.

25. The apparatus of claim 24, further comprising:

a channel estimator operative to estimate channel gains for the base station and the at least one neighbor base station, and wherein the controller is operative to determine the transmit power for the data transmission further based on the channel gains.

26. The apparatus of claim 20, wherein the processor is operative to obtain a quality of service (QoS) power control parameter, and wherein the controller is operative to determine the transmit power for the data transmission further based on the QoS power control parameter.

27. The apparatus of claim 20, wherein the processor is operative to obtain a minimum transmit power delta, and wherein the controller is operative to determine the transmit power for the data transmission further based on the minimum transmit power delta.

28. A method of controlling transmit power, comprising:

obtaining an overlapping factor that is indicative of an average number of overlapping transmissions; and

determining transmit power for a data transmission based on the overlapping factor.

29. The method of claim 28, further comprising:

receiving a transmit power control (TPC) command, and wherein the determining the transmit power for the data transmission comprises determining the transmit power for the data transmission further based on the received TPC command.

30. The method of claim 28, further comprising:

obtaining at least one indication of interference observed by at least one neighbor base station, and wherein the determining the transmit power for the data transmission comprises determining the transmit power for the data transmission further based on the at least one indication of interference.

31. The method of claim 28, further comprising:

obtaining a quality of service (QoS) power control parameter f, and wherein the determining the transmit power for the data transmission comprises determining the transmit power for the data transmission further based on the QoS power control parameter.

32. An apparatus comprising:

means for obtaining an overlapping factor that is indicative of an average number of overlapping transmissions; and

means for determining transmit power for a data transmission based on the overlapping factor.

33. The apparatus of claim 32, further comprising:

means for receiving a transmit power control (TPC) command fr, and wherein the means for determining the transmit power for the data transmission comprises means for determining the transmit power for the data transmission further based on the received TPC command.

34. The apparatus of claim 33, further comprising:

means for obtaining at least one indication of interference, and wherein the means for determining the transmit power for the data transmission comprises means for determining the transmit power for the data transmission further based on the at least one indication of interference.

35. The apparatus of claim 32, further comprising:

means for obtaining a quality of service (QoS) power control parameter, and wherein the means for determining the transmit power for the data transmission comprises means for determining the transmit power for the data transmission further based on the QoS power control parameter.