Power control protocol for highly variable data rate reverse link of a wireless communication system

• US 7,701,903 B2
• Filed: 02/13/2007
• Issued: 04/20/2010
• Est. Priority Date: 09/21/1998
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Inventors: Proctor, James A. Jr.
• Primary Examiner(s): Harper; Kevin C
• Application Number:
  US11/706,463
• Publication Number:
  US 20070140174A1
• Time in Patent Office: 1,162 Days
• Field of Search: 370/329, 370/464, 370/342, 370/465, 370/522
• US Class Current: 370/329
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/287 when the channel is in stand-by
• CPC Class Codes: H04W 52/288 taking into account the usage mode, e.g. hands-free, data transmission, telephone
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 52/58 Format of the TPC bits

Abstract

A technique for implementing closed loop power control in a wireless system using a modulation that requires synchronization over the radio channel, which dynamically assigns coded channels on a demand basis. The technique maintains a proper power level, even when no traffic channels are allocated, by determining a link quality metric based upon the reverse link power received. This determination is made in response to a heartbeat signal sent at a rate which is only sufficiently fast to maintain code phase lock, for example, depending upon the expected maximum rate at which the subscriber unit will travel.

Claims

1. A method for use in a base station for providing power control over dynamically assigned reverse link channels, the method comprising:

allocating a reverse link channel to a code division multiple access (CDMA) user device;

dividing the reverse link channel into multiple subchannels;

maintaining the transmit power level for the reverse link channel by sending a maintenance signal for each subchannel at a rate sufficient to maintain a code phase lock between the user device and the base station;

receiving a message from the CDMA user device over the reverse link channel, wherein the CDMA user device is powered on but not actively sending data;

determining a link quality metric for the received message; and

transmitting a power control bit and a grant on a forward link channel in response to the received message to adaptively control the transmit power level and data rate of the CDMA user device.

2. The method of claim 1 wherein the allocated reverse link channel is the only traffic channel allocated to the CDMA user device.

3. The method of claim 1 wherein the transmission rate of the message received from the CDMA user device depends on the maximum expected rate of physical movement of the CDMA user device.

4. The method of claim 1 wherein the link quality metric indicates a bit error measurement.

5. The method of claim 1 wherein the link quality metric indicates a noise level measurement.

6. The method of claim 1 wherein the link quality metric indicates a signal power level measurement.

7. The method of claim 1 wherein the power control bit is transmitted on a forward link paging channel.

8. The method of claim 1 wherein the power control bit is transmitted on a sync channel.

9. The method of claim 1 wherein the power control bit is transmitted on a pilot channel.

10. The method of claim 1 wherein the power control bit controls the transmission power level of the CDMA user device over the reverse traffic channel.

11. The method of claim 1 wherein the base station transmits and receives digital signals over at least one radio frequency channel via radio signals.

12. The method of claim 11 wherein each radio frequency channel comprises a plurality of subchannels wherein a plurality of different codes are assigned for each subchannel.

13. A method for use in a code division multiple access (CDMA) user device for providing power control over dynamically assigned reverse link channels, the method comprising:

receiving an allocated reverse link channel from a base station, the reverse link channel divided into a plurality of subchannels;

transmitting a message to the base station over the reverse link channel, wherein the CDMA user device is powered on but not actively sending data;

receiving a power control bit and a grant on a forward link channel from the base station in response to the transmitted message and based on a link quality metric of the transmitted message, the power control bit for each subchannel received at a rate sufficient to maintain a code phase lock between the user device and the base station; and

adaptively controlling and maintaining the transmit power level and data rate of the CDMA user device using the received power control bit and the grant.

14. The method of claim 13 wherein the allocated reverse link channel is the only traffic channel allocated to the CDMA user device.

15. The method of claim 13 wherein the transmission rate of the message transmitted to the base station depends on the maximum expected rate of physical movement of the CDMA user device.

16. The method of claim 13 wherein the link quality metric indicates a bit error measurement.

17. The method of claim 13 wherein the link quality metric indicates a noise level measurement.

18. The method of claim 13 wherein the link quality metric indicates a signal power level measurement.

19. The method of claim 13 wherein the power control bit is received on a forward link paging channel.

20. The method of claim 13 wherein the power control bit is received on a sync channel.

21. The method of claim 13 wherein the power control bit is received on a pilot channel.

22. The method of claim 13 wherein the power control bit controls the transmission power level of the CDMA user device over the reverse traffic channel.

23. The method of claim 13 wherein the CDMA user device transmits and receives digital signals over at least one radio frequency channel via radio signals.

24. The method of claim 23 wherein each radio frequency channel comprises a plurality of subchannels wherein a plurality of different codes are assigned for each subchannel.

25. A base station comprising:

an antenna;

a controller configured to allocate a reverse channel to a code division multiple access (CDMA) user device;

wherein the reverse link channel is divided into multiple subchannels;

a CDMA transceiver configured to receive a message from the CDMA user device over the reverse link, wherein the CDMA user device is powered on but not actively sending data;

wherein the controller is further configured to determine a link quality metric for the received message, and to maintain the transmit power level for the reverse link channel by sending a maintenance signal for each subchannel at a rate sufficient to maintain a code phase lock between the user device an the base station;

wherein the CDMA transceiver is further configured to transmit a power control bit and a grant on a forward link channel in response to the received message to adaptively control and maintain the transmit power level and data rate of the CDMA user device.

26. The base station of claim 25 wherein the allocated reverse link channel is the only traffic channel allocated to the CDMA user device.

27. The base station of claim 25 wherein the transmission rate of the message received from the CDMA user device depends on the maximum expected rate of physical movement of the CDMA user device.

28. The base station of claim 25 wherein the link quality metric indicates a bit error measurement.

29. The base station of claim 25 wherein the link quality metric indicates a noise level measurement.

30. The base station of claim 25 wherein the link quality metric indicates a signal power level measurement.

31. The base station of claim 25 wherein the power control bit is transmitted on a forward link paging channel.

32. The base station of claim 25 wherein the power control bit is transmitted on a sync channel.

33. The base station of claim 25 wherein the power control bit is transmitted on a pilot channel.

34. The base station of claim 25 wherein the power control bit controls the transmission power level of the CDMA user device over the reverse traffic channel.

35. The base station of claim 25 wherein the base station transmits and receives digital signals over at least one radio frequency channel via radio signals.

36. The base station of claim 35 wherein each radio frequency channel comprises a plurality of subchannels wherein a plurality of different codes are assigned for each subchannel.

37. A code division multiple access (CDMA) user device comprising:

an antenna;

a CDMA transceiver configured to receive an allocated reverse link channel from a base station and to transmit a message to the base station over the reverse link channel, wherein the CDMA user device is powered on but not actively sending data and wherein the reverse link channel is divided into multiple subchannels;

a controller configured to maintain the reverse link channel between the CDMA user device and the base station;

wherein the controller is further configured to maintain the transmit power level for the reverse link channel by sending a maintenance signal for each subchannel at a rate sufficient to maintain a code phase lock between the user device an the base station; and

wherein the CDMA transceiver is further configured to receive a power control bit and a grant on a forward link channel in response to the transmitted message from the base station to control the transmit power level and data rate of the CDMA user device.

38. The CDMA user device of claim 37 wherein the allocated reverse link channel is the only traffic channel allocated to the CDMA user device.

39. The CDMA user device of claim 37 wherein the transmission rate of the message transmitted to the base station depends on the maximum expected rate of physical movement of the CDMA user device.

40. The CDMA user device of claim 37 wherein the link quality metric indicates a bit error measurement.

41. The CDMA user device of claim 37 wherein the link quality metric indicates a noise level measurement.

42. The CDMA user device of claim 37 wherein the link quality metric indicates a signal power level measurement.

43. The CDMA user device of claim 37 wherein the power control bit is received on a forward link paging channel.

44. The CDMA user device of claim 37 wherein the power control bit is received on a sync channel.

45. The CDMA user device of claim 37 wherein the power control bit is received on a pilot channel.

46. The CDMA user device of claim 37 wherein the power control bit controls the transmission power level of the CDMA user device over the reverse traffic channel.

47. The CDMA user device of claim 37 wherein the CDMA user device transmits and receives digital signals over at least one radio frequency channel via radio signals.

48. The CDMA user device of claim 47 wherein each radio frequency channel comprises a plurality of subchannels wherein a plurality of different codes are assigned for each subchannel.