Method and apparatus for pre-transmission power control using lower rate for high rate communication

• US 6,330,462 B1
• Filed: 12/14/1999
• Issued: 12/11/2001
• Est. Priority Date: 07/01/1997
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chen, Tao
• Primary Examiner(s): TIEU, BINH KIEN
• Application Number:
  US09/460,873
• Time in Patent Office: 728 Days
• Field of Search: 455/15, 455/39, 455/63, 455/67.1, 455/69, 455/504, 455/507, 455/517, 455/522, 455/572
• US Class Current: 455/572
• CPC Class Codes: H04W 52/267 taking into account the information rate

Abstract

The present invention employs a method and apparatus for providing improved power control when changing the rate at which data is sent in a communications system. When data arrives at the transmitter for transmission at a high rate, power control feedback is changed from a slow mode (with a low bandwidth feedback channel) to a fast mode (with a high bandwidth feedback channel). This control changes even before the data is transmitted at the high rate. Once the power level is accurately estimated for data transmission at the high rate, then data transmission begins at the high rate.

Claims

1. In a communication system having at least one base station and at least one user station, wherein a user of said user station transmits reverse link signals to and receives forward link signals from said base station, a method for controlling transmission signal power in said communication system, the method comprising the steps of:

sending signals at a low rate transmission signal power from at least one of said user stations and said base station;

selecting a transmission signal power required to send data signals at a data rate based on improved quality feedback power control information signals, said data rate being faster than said low rate;

changing said low rate transmission signal power to match said selected transmission signal power for said data rate;

sending data signals at said data rate from at least one of said user stations and said base station.

2. The method of claim 1 further characterized in that said data rate is a multiple of said low rate, said multiple having a value greater than 4.

3. The method of claim 1 wherein said estimating step further includes:

(1) determining a received power based on said improved quality feedback power control information signals; and

(2) evaluating said transmission signal power required to send data signals at a data rate using said received power.

4. A method for a power control of a communication system, having at least one transmitting station and at least one receiving station, during a transition from a lower data rate to a higher data rate,

(a) comprising the steps of:

(1) exchanging signals between said transmitting station and said receiving station over forward and reverse links at a low rate;

(2) presenting data to said transmitting station for transmission at a data rate, said data rate being higher than said low rate;

(3) estimating at said transmitting station a transmission signal power required to transmit data at said data rate based on a feedback power control information signals received from said receiving station;

(4) changing at said transmitting station said transmission signal power to said required transmission signal power,

(5) starting at said transmitting station transmission of data at said data rate; and

(b) the improvement is characterized in that the method includes the step of;

(1) improving quality of said feedback power control information signals, said step preceding the step of estimating a transmission power;

(c) wherein if said transmitting station is a base station then said receiving station is a remote station and vice versa.

5. The method of claim 4 further characterized in that:

(a) said forward and reverse links each comprise a communication channel and a feedback channel, each channel having a separate bandwidth; and

(b) said feedback power control information signals are exchanged over said feedback channel.

6. The method of claim 4 further characterized in that the method includes the step of:

transmitting a notification from said transmitting station to said receiving station that said transmitting station is beginning to transmit data at said data rate, said step preceding the step of starting at said transmitting station transmission of data at said data rate.

7. The method of claim 4 further characterized in that the step of improving quality of said feedback power control information signals comprises the steps of:

(a) transmitting a request from said transmitting station to said receiving station to increase a bandwidth of said feedback power control information signals; and

(b) increasing said bandwidth by said receiving station in response to said signal.

8. The method of claim 4 further characterized in that the step of improving quality of said feedback power control information signals comprises the step of:

changing a transmission rate at said transmitting station to a full rate, said full rate being a rate between said low rate and said data rate.

9. The method of claim 4 further characterized in that the step of improving quality of said feedback power control information signals comprises the step of:

changing a transmission rate at said transmitting station to said data rate for a short duration of time.

10. The method of claim 4 further characterized in that the step of improving quality of said feedback power control information signals comprises the steps of:

(a) transmitting a request from said transmitting station to said receiving station to increase a bandwidth of said feedback power control information signals;

(b) increasing said bandwidth by said receiving station in response to said signal, and

(c) changing a transmission rate at said transmitting station to a full rate, said full rate being a rate between said low rate and said data rate.

11. The method of claim 4 further characterized in that the step of improving quality of said feedback power control information signals comprises the steps of:

(a) transmitting a request from said transmitting station to said receiving station to increase a bandwidth of said feedback power control information signals;

(b) increasing said bandwidth by said receiving station in response to said signal, and

(c) changing a transmission rate at said transmitting station to said data rate for a short duration of time.

12. The method of claim 4 further characterized in that the step of estimating said transmission power further includes the steps of:

(a) determining an error rate based on improved quality of said feedback power control information signals; and

(b) evaluating said transmission signal power required using said error rate.

13. The method of claim 4 further characterized in that the step of estimating said transmission power further includes the steps of:

(a) determining a received power based on improved quality of said feedback power control information signals; and

(b) evaluating said transmission signal power required using said received power.

14. The method of claim 8 further characterized in that the method includes the step of:

transmitting a notification from said transmitting station to said receiving station that said transmitting station will change transmission rate to a full rate, said full rate being a rate between said low and data rates;

said step preceding the step of changing a transmission rate.

15. An apparatus for a power control of a communication system, having at least one transmitting station and at least one receiving station, during a transition from a lower data rate to a higher data rate,

(a) comprising:

(1) means for exchanging signals between said transmitting station and said receiving station at a low rate;

(2) means for presenting data to said transmitting station for transmission at a data rate, said data rate being higher than said low rate;

(3) means for estimating at said transmitting station a transmission signal power required to transmit data at said data rate based a feedback power control information signals from said B station;

(4) means for changing at said transmitting station said transmission signal power to said required transmission signal power,

(5) means for starting at said transmitting station transmission of data at said data rate; and

(b) the improvement is characterized in that the apparatus further includes;

(1) means for improving quality of said feedback power control information signals, said improvement of quality occurring before said estimation of a transmission power;

(c) wherein if said transmitting station is a base station then said receiving station is a remote station and vice versa.

16. The apparatus of claim 15 further characterized in that:

(a) said forward and reverse links each comprise a communication channel and a feedback channel, each channel having a separate bandwidth; and

(b) said feedback power control information signals are exchanged over said feedback channel.

17. The apparatus of claim 15 further characterized in that the apparatus includes:

means for transmitting a notification from said transmitting station to said receiving station that said transmitting station is beginning to transmit data at said data rate, said notification occurring before said start of transmission of data at said data rate.

18. The apparatus of claim 15 further characterized in that the means for improving quality of said feedback power control information signals comprises:

(a) means for transmitting a request from said transmitting station to said receiving station to increase a bandwidth of said feedback power control information signals; and

(b) means for increasing said bandwidth by said receiving station in response to said signal.

19. The apparatus of claim 15 further characterized in that the means for improving quality of said feedback power control information signals comprises:

means for changing a transmission rate at said transmitting station to a full rate, said full rate being a rate between said low rate and said data rate.

20. The apparatus of claim 15 further characterized in that the means for improving quality of said feedback power control information signals comprises:

means for changing a transmission rate at said transmitting station to said data rate for a short duration of time.

21. The apparatus of claim 15 further characterized in that the means for improving quality of said feedback power control information signals comprises:

(a) means for transmitting a request from said transmitting station to said receiving station to increase a bandwidth of said feedback power control information signals;

(b) means for increasing said bandwidth by said receiving station in response to said signal, and

(c) means for changing a transmission rate at said transmitting station to a full rate, said full rate being a rate between said low rate and said data rate.

22. The apparatus of claim 15 further characterized in that the means for improving quality of said feedback power control information signals comprises:

(a) means for transmitting a request from said transmitting station to said receiving station to increase a bandwidth of said feedback power control information signals;

(b) means for increasing said bandwidth by said receiving station in response to said signal, and

(c) means for changing a transmission rate at said transmitting station to said data rate for a short duration of time.

23. The apparatus of claim 15 further characterized in that:

means for estimating said transmission power further include;

(1) means for determining an error rate based on improved quality of said feedback power control information signals; and

(2) means for evaluating said transmission signal power required using said error rate.

24. The apparatus of claim 15 further characterized in that said data rate is a multiple of said low rate, said multiple having a value greater than 4.

25. The apparatus of claim 19 further characterized in that the apparatus includes:

means for transmitting a notification from said transmitting station to said receiving station that said transmitting station will change transmission rate to a full rate, said full rate being a rate between said low and data rates;

said step preceding the step of changing a transmission rate.

26. An apparatus for a power control of a communication system during a transition from a lower data rate to a higher data rate, said communication system comprises:

(a) a transmitting station comprising;

(1) a variable data source;

(2) a first transmitter adapted to receive data from said data source, constructed to transmit a signal at said data rate and a variable power to a second receiver over a first link;

(3) a first receiver constructed to receive a signal from a second transmitter; and

(4) a first control processor connected to said variable data source, said first transmitter, and said first receiver; and

(b) a receiving station comprising;

(1) said second transmitter constructed to transmit a signal to said first receiver over a second link;

(2) said second receiver constructed to receive a signal from said first transmitter; and

(3) a second control processor connected to said second transmitter, and said second receiver; and

(c) wherein the apparatus is characterized in that;

(1) said first control processor has been configured to perform the following functions;

(a) to cause said first transmitter to transmit signals at a low rate;

(b) to receive request from said variable data source to cause said first transmitter to transmit signals at a data rate, said data rate being higher than said low rate;

(c) to cause said first transmitter to transmit a signal causing said receiving station to improve quality of a feedback power control information signals;

(d) to receive from said first receiver said feedback power control information signals;

(e) to estimate a transmission signal power required to transmit data at said data rate based on improved quality of said feedback power control information signals;

(f) to cause said first transmitter to change said transmission signal power to said required transmission signal power; and

(g) to cause said first transmitter to start transmission of data at said data rate; and

(2) said second control processor has been configured to perform the following functions;

(a) to receive from said second receiver a signal indicating a need to improve a quality of said feedback power control information signals;

(b) to cause an improvement of quality of said feedback power control information signals; and

(c) to cause said transmitter to transmit said feedback power control information signals;

(d) wherein if said transmitting station is a base station then said receiving station is a remote station and vice versa.

27. The apparatus of claim 26 further characterized in that:

said second link comprise a communication channel and a feedback channel; and

said second transmitter is constructed to transmit said feedback power control information signal over said feedback channel.

28. The apparatus of claim 26 further characterized in that:

said first control processor has been configured to perform a function to cause said first transmitter to transmit a notification to said receiving station that said first transmitter is beginning to transmit data at said data rate, said function preceding function (g).

29. The apparatus of claim 26 further characterized in that:

(a) said first control processor has been configured to modify function (c) in that said signal causing said receiving station to improve quality of a feedback power control information signals comprises a request to increase a bandwidth of said feedback power control information signals; and

(b) said second control processor has been configured to modify function (b) in that said improvement of quality of said feedback power control information signals comprises an increase of said bandwidth of said feedback power control information signals.

30. The apparatus of claim 26 further characterized in that:

(a) said first control processor has been configured to modify function (c) in that said signal causing said receiving station to improve quality of a feedback power control information signals comprises an increase of a transmission rate from said low rate to a full rate, said full rate being a rate between said low rate and said data rate; and

(b) said second control processor has been configured to modify function (b) in that said improvement of quality of said feedback power control information signals comprises more accurate estimate of a power control information due to said full rate.

31. The apparatus of claim 26 further characterized in that:

(a) said first control processor has been configured to modify function (c) in that said signal causing said receiving station to improve quality of a feedback power control information signals comprises an increase of a transmission rate from said low rate to said data rate for a short duration of time; and

(b) said second control processor has been configured to modify function (b) in that said improvement of quality of said feedback power control information signals comprises more accurate estimate of a power control information due to said data rate.

32. The apparatus of claim 26 further characterized in that:

(a) said first control processor has been configured to modify function (c) in that said signal causing said receiving station to improve quality of a feedback power control information signals comprises a request to increase a bandwidth of said feedback power control information signals and an increase of a transmission rate from said low rate to said full rate; and

(b) said second control processor has been configured to modify function (b) in that said improvement of quality of said feedback power control information signals comprises an increase of said bandwidth of said feedback power control information signals and more accurate estimate of a power control information due to said full rate.

33. The apparatus of claim 26 further characterized in that:

(a) said first control processor has been configured to modify function (c) in that said signal causing said receiving station to improve quality of a feedback power control information signals comprises a request to increase a bandwidth of said feedback power control information signals and an increase of a transmission rate from said low rate to said data rate for a short duration of time; and

(b) said second control processor has been configured to modify function (b) in that said improvement of quality of said feedback power control information signals comprises an increase of said bandwidth of said feedback power control information signals and more accurate estimate of a power control information due to said data rate.

34. The apparatus of claim 26 further characterized in that:

said first control processor has been configured to modify function (e) in that said estimate of said transmission power comprises;

(1) determining an error rate based on improved quality of said feedback power control information signals; and

(2) evaluating said transmission signal power required using said error rate.

35. The apparatus of claim 26 further characterized in that:

said first control processor has been configured to modify function (e) in that said estimate of said transmission power comprises;

(1) determining a received power based on improved quality of said feedback power control information signals; and

(2) evaluating said transmission signal power required using said received power.

36. The apparatus of claim 26 further characterized in that:

said first control processor has been configured to perform a function to cause said first transmitter to transmit a notification to said receiving station that said first transmitter will change transmission rate to a full rate, said full rate being a rate between said low and data rates, wherein said function precedes function (g).

48. The apparatus of claim 26 further characterized in that:

said link comprise a communication channel and a feedback channel; and

said transmitter is constructed to transmit said feedback power control information signal over said feedback channel.

37. An apparatus for a power control of a communication system having at least one transmitting station and at least one receiving station during a transition from a lower data rate to a higher data rate,

(a) said apparatus comprising:

(1) a variable data source;

(2) a transmitter adapted to receive data from said data source, constructed to transmit a signal at a variable data rate and a variable power;

(3) a receiver constructed to receive a signal a variable data rate; and

(4) a control processor connected to said variable data source, said transmitter, and said receiver; and

(b) wherein the apparatus is characterized in that;

(1) said control processor has been configured to perform the following functions;

(a) to cause said first transmitter to transmit signals at a low rate;

(b) to receive notification from said variable data source to cause first transmitter to transmit signals at a data rate, said data rate being higher than said low rate;

(c) to cause said transmitter to transmit a signal requesting an opposite type station to improve quality of a feedback power control information signals;

(d) to receive from said receiver said feedback power control information signals;

(e) to estimate a transmission signal power required to transmit data at said data rate based on improved quality of said feedback power control information signals;

(f) to cause said transmitter to change said transmission signal power to said required transmission signal power; and

(g) to cause said transmitter to start transmission of data at said data rate; and

(c) wherein said apparatus resides in said transmitting station or said receiving station or both.

38. The apparatus of claim 37 further characterized in that:

said control processor has been configured to perform a function to cause said transmitter to transmit a notification to said opposite 4 type station that said transmitter is beginning to transmit data at said data rate, said function preceding function (g).

39. The apparatus of claim 37 further characterized in that

said control processor has been configured to modify function (c) in that said signal causing said opposite type station to improve quality of a feedback power control information signals comprises a request to increase a bandwidth of said feedback power control information signals.

40. The apparatus of claim 37 further characterized in that:

said control processor has been configured to modify function (c) in that said signal causing said opposite type station to improve quality of a feedback power control information signals comprises an increase of a transmission rate from said low rate to a full rate, said full rate being a rate between said low rate and said data rate.

41. The apparatus of claim 37 further characterized in that:

said control processor has been configured to modify function (c) in that said signal causing said opposite type station to improve quality of a feedback power control information signals comprises an increase of a transmission rate from said low rate to said data rate for a short duration of time.

42. The apparatus of claim 37 further characterized in that:

said control processor has been configured to modify function (c) in that said signal causing said opposite type station to improve quality of a feedback power control information signals comprises a request to increase a bandwidth of said feedback power control information signals and an increase of a transmission rate from said low rate to said full rate.

43. The apparatus of claim 37 further characterized in that:

said control processor has been configured to modify function (c) in that said signal causing said opposite type station to improve quality of a feedback power control information signals comprises a request to increase a bandwidth of said feedback power control information signals and an increase of a transmission rate from said low rate to said data rate for a short duration of time.

44. The apparatus of claim 37 further characterized in that:

said control processor has been configured to modify function (e) in that said estimate of said transmission power comprises;

(1) determining an error rate based on improved quality of said feedback power control information signals; and

(2) evaluating said transmission signal power required using said error rate.

45. The apparatus of claim 37 further characterized in that:

said control processor has been configured to modify function (e) in that said estimate of said transmission power comprises;

(1) determining a received power based on improved quality of said feedback power control information signals; and

(2) evaluating said transmission signal power required using said received power.

46. The apparatus of claim 43 further characterized in that:

said control processor has been configured to further perform the function to cause said transmitter to transmit a notification to said receiving station that said transmitter will change transmission rate to a full rate, said full rate being a rate between said low and data rates, wherein said function precedes function (g).

47. An apparatus for a power control of a communication system having at least one transmitting station and at least one receiving station during a transition from a lower data rate to a higher data rate:

(a) said apparatus comprising;

(1) a transmitter constructed to transmit a signal at a variable data rate and a variable power over a link;

(2) a receiver constructed to receive a signal at a variable data rate; and

(3) a control processor connected to said transmitter, and said receiver; and

(b) wherein the apparatus is characterized in that;

(4) said control processor has been configured to perform the following functions;

(a) to receive from said receiver a signal indicating a need to improve a quality of said feedback power control information signals;

(b) to cause improvement of quality of said feedback power control information signals; and

(c) to cause said transmitter to transmit said feedback power control information signals;

(c) wherein said apparatus resides in said transmitting station or said receiving station or both.

49. The apparatus of claim 47 further characterized in that:

said control processor has been configured to modify function (b) in that said improvement of quality of said feedback power control information signals comprises an increase of a bandwidth of said feedback power control information signals.

50. The apparatus of claim 47 further characterized in that:

said control processor has been configured to modify function (b) in that said improvement of quality of said feedback power control information signals comprises more accurate estimate of a power control information due to an increased rate received by said receiver.

51. A method for controlling transmission power in a communication system, having at least one transmitting station and at least one receiving station, during a transition from a low rate to a high rate transmission, comprising the steps of:

(1) improving a quality of feedback power control information signals to generate an improved feedback power control information signals;

(2) estimating a transmission power required to transmit data at said high rate based on said improved feedback power control information signals; and

(3) transmitting at said high rate using said required transmission power.

52. The method of claim 51 further including:

(a) exchanging signals between said transmitting station and said receiving station over forward and reverse links, wherein said forward and reverse links each comprise a communication channel and a feedback channel, each channel having a separate bandwidth, and said feedback power control information signals are exchanged over said feedback channel.

53. The method of claim 51 further including:

(a) transmitting a notification from said transmitting station to said receiving station t ha t said transmitting station is beginning to transmit data at said high rate, said step preceding the step of transmitting at said high rate.

54. The method of claim 51 wherein the step of improving said quality of said feedback power control information signals includes the steps of:

(a) transmitting a request from said transmitting station to said receiving station to increase a bandwidth of said feedback power control information signals; and

(b) increasing said bandwidth by said receiving station in response to said signal.

55. The method of claim 51 wherein the step of improving said quality of said feedback power control information signals includes the step of:

(a) changing a transmission rate at said transmitting station to a full rate, said full rate being a rate between said low rate and said high rate.

56. The method of claim 55 wherein the step of changing said transmission rate includes changing said transmission rate for a short duration of time.

57. The method of claim 51 wherein the step of improving said quality of said feedback power control information signals includes the steps of:

(a) transmitting a request from said transmitting station to said receiving station to increase a bandwidth of said feedback power control information signals;

(b) increasing said bandwidth by said receiving station in response to said request; and

(c) changing a transmission rate at said transmitting station to a full rate, said full rate being a rate between said low rate and said high rate.

58. The method of claim 57 wherein the step of changing said transmission rate includes changing said transmission rate for a short duration of time.

59. The method of claim 51 wherein the step of estimating said transmission power further includes the steps of:

(a) determining an error rate based on said improved feedback power control information signals; and

(b) estimating said transmission signal power required using said error rate.

60. The method of claim 51 wherein the step of estimating said transmission power further includes the steps of:

(a) determining a received power based on said improved quality of said feedback power control information signals; and

(b) estimating said required transmission signal power using said received power.

61. The method of claim 55 further including the step of:

transmitting a notification from said transmitting station to said receiving station that said transmitting station will change transmission rate to a full rate, said full rate being a rate between said low and high rates;

said step preceding the step of changing said transmission rate.

62. An apparatus for controlling transmission power in a communication system, having at least one transmitting station and at least one receiving station, during a transition from a low rate to a high rate transmission, said apparatus comprising:

(a) a transmitter configured to transmit at a variable data rate and a variable power over a first link;

(b) a receiver configured to receive at a variable rate and a variable power over a second link; and

(c) a control processor connected to said transmitter and said receiver, said control processor further including;

(1) means for receiving from said receiver a request for improving a quality of feedback power control information signals;

(2) means for improving said quality of said feedback power control information signals; and

(3) means for transmitting said improved feedback power control information signals to said transmitter.

63. The apparatus of claim 62 wherein said means for improving said quality of said feedback power control information signals further includes means for increasing a bandwidth of said feedback power control information signals.

64. The apparatus of claim 62 wherein said means for improving said quality of said feedback power control information signals further includes means for increasing a transmission rate for said feedback power control information signals.

65. The apparatus of claim 62 wherein said second link comprises a communication channel and a feedback channel, and said improved feedback power control information signals are transmitted over said feedback channel.

66. The apparatus of claim 62 wherein said control processor further includes means for transmitting a notification to said receiving station that said transmitter is beginning to transmit at said high rate.