Centralized medium access control algorithm for CDMA reverse link

• US 20070178927A1
• Filed: 05/25/2006
• Published: 08/02/2007
• Est. Priority Date: 01/27/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Fernandez-Corbaton, Ivan, Jalali, Ahmad, Pinos Pont, Jordi
• Granted Patent: US 8,254,977 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range

Abstract

A novel MAC algorithm is disclosed having various features for a modern CDMA interference-shared reverse link, including (a) link quality assurance, (b) individual congestion control, (c) variable data rate transition policy, and/or (d) reverse link partitioning. Link quality assurance is provided by monitoring transmission feedback information (ACK/NACK) to indirectly determine the quality of a communication link. Wireless devices are individually targeted to perform congestion control of the reverse link. Variable data transmission rates and discontinuous transmissions are achieved by individual wireless devices that autonomously adjust their transmission rate and transmit power. The reverse link can also be partitioned among the different wireless devices by individually controlling the transmit power of the wireless devices operating on the reverse link.

Claims

1. An apparatus comprising:

a communication interface for wirelessly communicating with one or more wireless devices through an interference shared communication channel; and

a processing unit coupled to the communication interface and configured to

determine a maximum received power limit for each of the one or more wireless devices, and

send individualized power control commands to the one or more wireless devices to maintain their received power within their corresponding maximum received power limit.

2. The apparatus of 1 wherein the processing unit is further configured to

determine whether channel congestion is present in the communication channel.

3. The apparatus of 2 wherein congestion is present if a ratio of the total power received from all wireless devices and the thermal noise for the communication channel is greater than a threshold amount.

4. The apparatus of 2 wherein the processing unit is further configured to

adjust one or more of the maximum received power limits to reduce channel congestion if channel congestion is present.

5. The apparatus of 1 wherein the processing unit is further configured to

partition the reverse link of the communication channel among the one or more wireless devices.

6. The apparatus of 5 wherein partitioning the reverse link of the communication channel includes proportionally partitioning the reverse link of the communication channel among all wireless devices with which the apparatus communicates.

7. The apparatus of 5 wherein the partitioning of the reverse link is accomplished by individually adjusting the maximum received power limit for one or more wireless devices to achieve a desired partition.

8. The apparatus of 1 wherein the processing unit is further configured to

determine a minimum received power limit for each of the one or more wireless devices, and

send a power control command to one or more of the wireless devices to maintain their received power above their corresponding minimum received power limit.

9. A device for implementing medium access control, comprising:

means for determining a maximum received power limit for each of one or more wireless devices operating on an interference shared communication channel;

means for determining whether congestion is present in the communication channel; and

means for implementing selective transmit power control of the one or more wireless devices to achieve a desired congestion level.

10. The device of claim 9 further comprising:

means for partitioning the reverse link of the communication channel among the one or more wireless devices operating on the reverse link of the communication channel by individually adjusting the maximum received power limit for the one or more wireless devices.

11. A method for implementing medium access control comprising:

determining a maximum received power limit for each of one or more wireless devices operating on an interference shared communication channel;

determining whether congestion is present in the communication channel; and

implementing selective transmit power control of one or more of the wireless devices to achieve a desired congestion level.

12. The method of 11 further comprising:

partitioning the reverse link of the communication channel among the one or more wireless devices.

13. The method of 12 further comprising:

individually adjusting the maximum received power limit for one or more wireless devices to achieve a desired partitioning.

14. The method of 11 further comprising:

determining a minimum received power limit for each of the one or more wireless devices, and

sending a power control command to one or more of the wireless devices to maintain their received power above their corresponding minimum received power limit.

15. A processing unit configured to control:

communicating with one or more wireless devices through an interference shared communication channel;

determining a maximum received power limit for each of one or more wireless devices communicating on an interference shared communication channel;

sending a power control command to a wireless device to maintain its received power within its corresponding maximum received power limit;

determining whether congestion is present in the communication channel; and

reducing congestion by adjusting one or more of the maximum received power limits if congestion is greater than a threshold level.

16. The processing unit of 15 further configured to control:

partitioning the reverse link of the communication channel among a plurality of the one or more wireless devices operating on the communication channel.

17. A machine-readable medium comprising instructions executable by a processor for medium access control of an interference shared communication channel, which when executed by a processor, causes the processor to perform operations comprising:

determining a maximum received power limit for each of one or more wireless devices operating on the interference shared communication channel;

determining whether congestion is present in the communication channel; and

implementing selective transmit power control of one or more of the wireless devices to maintain the communication channel at or below a threshold congestion level.

18. The machine-readable medium of 17 further comprising:

individually adjusting the maximum received power limit for one or more wireless devices to partition the reverse link of the communication channel among the one or more wireless devices.

19. An apparatus comprising:

a wireless communication interface having an adjustable transmit power, the wireless communication interface for communicating with a base station via an interference shared reverse link communication channel; and

a processing unit coupled to the wireless communication interface and configured to

obtain a maximum transmit power limit, and

autonomously adjust a transmission rate and the transmit power to meet a desired grade of service while maintaining the transmit power at or below the maximum transmit power limit.

20. The apparatus of 19 wherein the processing unit is further configured to

obey power control commands received through the wireless communication interface by adjusting the transmit power according to the power control commands.

21. The apparatus of 19 wherein the processing unit is further configured to

monitor the receipt of power control commands;

and

determine the maximum transmit power limit by ascertaining the power levels at which power control commands are received.

22. The apparatus of 19 wherein the processing unit is further configured to

receive feedback information related to the decoding of previously transmitted information;

and

determine a quality of service for the reverse link communication channel based on the feedback information.

23. The apparatus of 22 wherein the received feedback information includes acknowledgements of whether transmitted information was successfully decoded.

24. The apparatus of 22 wherein the quality of service is a frame error rate.

25. The apparatus of 22 wherein the processing unit is further configured to

adjust the transmit power so that the quality of service for the reverse link communication channel meets the desired grade of service.

26. The apparatus of 22 wherein the processing unit is further configured to

adjust the transmission rate so that the quality of service for the reverse link communication channel meets the desired grade of service.

27. A wireless device comprising:

means for obtaining a maximum transmit power limit; and

means for autonomously adjusting a reverse link transmission rate and transmit power to meet a desired grade of service while maintaining the transmit power at or below the maximum transmit power limit.

28. The wireless device of 27 further comprising:

means for receiving power control commands; and

means for estimating the maximum transmit power limit by ascertaining the power levels at which power control commands are received.

29. The wireless device of 32 further comprising:

means for determining a quality of service for the reverse link communication channel based on feedback of whether transmitted information was successfully decoded; and

means for adjusting the reverse link transmission rate and transmit power so that the quality of service meets the desired grade of service.

30. A method for media access control operational on a wireless device, comprising

obtaining a maximum transmit power limit;

and

autonomously adjusting a reverse link transmission rate and transmit power to meet a desired grade of service while maintaining the transmit power at or below the maximum transmit power limit.

31. The method of 30 further comprising:

monitoring the receipt of power control commands;

obeying power control commands received by adjusting the transmit power according to the power control commands; and

determining the maximum transmit power limit by ascertaining the power levels at which power control commands are received.

32. The method of 30 further comprising:

receiving acknowledgements of whether transmitted information was successfully decoded; and

determining a quality of service for the reverse link communication channel based on the received acknowledgements.

33. The method of 30 further comprising:

receiving power control down commands from two or more sectors;

selecting the lowest of the maximum transmit power limits associated with the two or more sectors; and

transmitting on the lowest of the maximum transmit power limits.

34. A processing unit configured to control:

communicating with a base station through an interference shared reverse link communication channel;

obtain a maximum transmit power limit; and

autonomously adjusting a reverse link transmission rate and transmit power to meet a desired grade of service while maintaining the transmit power at or below the maximum transmit power limit.

35. The processing unit of 34 further configure to control:

monitoring the receipt of power control commands; and

estimating the maximum transmit power limit by ascertaining the power levels at which power control commands are received.

36. The processing unit of 34 further configure to control:

determining a quality of service for the reverse link communication channel based on feedback of whether transmitted information was successfully decoded; and

adjusting the reverse link transmission rate and transmit power so that the quality of service meets the desired grade of service.

37. A machine-readable medium comprising instructions executable by a processor for medium access control of an interference shared communication channel, which when executed by a processor, causes the processor to perform operations comprising:

obtaining a maximum transmit power limit; and

autonomously adjusting a reverse link transmission rate and transmit power to meet a desired grade of service while maintaining the transmit power at or below the maximum transmit power limit.