DOWNLINK FLOW CONTROL

• US 20090161545A1
• Filed: 12/18/2008
• Published: 06/25/2009
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ho, Sai Yiu Duncan, Klingenbrunn, Thomas, Maheshwari, Shailesh, Meylan, Arnaud, Grilli, Francesco, Chaponniere, Etienne F.
• Granted Patent: US 8,917,598 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 1/001 applied to control information
• CPC Class Codes: H04L 47/225 Determination of shaping rate, e.g. using a moving window
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/39 Credit based
• CPC Class Codes: H04W 28/0205 at the air interface dynamic wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 28/0236 radio quality, e.g. interference, losses or delay
• CPC Class Codes: H04W 28/10 Flow control between communication endpoints
• CPC Class Codes: H04W 28/12 using signalling between network elements
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

Systems and methodologies are described that facilitate providing flow control feedback for controlling downlink data transmission rates. Various schemes can be utilized to send the flow control feedback from an access terminal to a base station. For example, a control PDU (e.g., MAC control PDU, PDCP control PDU) can be generated based upon a level of resource utilization of the access terminal, and sent to the base station for controlling the downlink data transmission rate. Following this example, a type of control PDU, a value included within the control PDU, etc. can be selected as a function of the level of resource utilization. By way of another illustration, a CQI report that includes a value selected as a function of the level of resource utilization associated with the access terminal can be generated and transmitted to the base station for controlling the downlink data transmission rate.

Claims

1. A method that facilitates providing downlink flow control in a wireless communication environment, comprising:

monitoring resource use associated with an access terminal;

generating a control protocol data unit (PDU) based upon the resource use associated with the access terminal; and

sending the control PDU to a base station to manage a downlink data transmission rate.

2. The method of claim 1, wherein the control PDU is a Media Access Control (MAC) control PDU.

3. The method of claim 2, further comprising:

generating a type 1 MAC control PDU when resource use of the access terminal is determined to be above a first threshold; and

generating a type 2 MAC control PDU when resource use of the access terminal is determined to be below a second threshold.

4. The method of claim 2, further comprising:

generating a type 1 MAC control PDU that includes a binary value set to 0 when resource use of the access terminal is determined to be above a first threshold; and

generating a type 1 MAC control PDU that includes a binary value set to 1 when resource use of the access terminal is determined to be below a second threshold.

5. The method of claim 2, further comprising:

determining an average detected downlink data transmission rate experienced by the access terminal in a given time window;

identifying a preferred downlink data transmission rate for the access terminal as a function of the monitored resource use;

generating a type 1 MAC control PDU that includes a first selected value corresponding to a percentage decrease from the average detected downlink data transmission rate to the preferred downlink data transmission rate when the preferred downlink data transmission rate is less than the average detected downlink data transmission rate; and

generating a type 2 MAC control PDU that includes a second selected value corresponding to a percentage increase from the average detected downlink data transmission rate to the preferred downlink data transmission rate when the preferred downlink data transmission rate is greater than the average detected downlink data transmission rate.

6. The method of claim 2, further comprising:

determining an updated downlink data transmission rate to be utilized by a base station for subsequent transmission for the access terminal based upon the monitored resource use;

comparing the updated downlink data transmission rate to a previously signaled downlink data transmission rate to be utilized by the base station;

generating a type 1 MAC control PDU that includes a first selected value corresponding to a percentage decrease from the previously signaled downlink data transmission rate to the updated downlink data transmission rate when the updated downlink data transmission rate is less than the previously signaled downlink data transmission rate; and

generating a type 2 MAC control PDU that includes a second selected value corresponding to a percentage increase from the previously signaled downlink data transmission rate to the updated downlink data transmission rate when the updated downlink data transmission rate is greater than the previously signaled downlink data transmission rate.

7. The method of claim 1, wherein the control PDU is a Packet Data Convergence Protocol (PDCP) control PDU.

8. The method of claim 7, wherein the PDCP control PDU indicates at least one of a highest PDCP Sequence Number (SN), a highest Count-C which includes Hyper Frame Number (HFN) plus PDCP SN, or a part of a Count-C permitted to be transmitted by the base station.

9. The method of claim 7, wherein the PDCP control PDU indicates a maximum number of PDCP PDUs allowed to be transmitted by the base station in a Transmission Time Interval (TTI).

10. The method of claim 7, wherein the PDCP control PDU switches an associated PDCP bearer between an on state and an off state.

11. A wireless communications apparatus, comprising:

a memory that retains instructions related to generating a control protocol data unit (PDU) based upon detected resource use associated with an access terminal, and transmitting the control PDU to a base station to control a downlink data transmission rate; and

a processor, coupled to the memory, configured to execute the instructions retained in the memory.

12. The wireless communications apparatus of claim 11, wherein the memory further retains instructions related to generating a first type of control PDU when resource use of the access terminal is above a first threshold, and generating a second type of control PDU when resource use of the access terminal is below a second threshold.

13. The wireless communications apparatus of claim 11, wherein the memory further retains instructions related to generating a control PDU that includes a binary value set to 0 when resource use of the access terminal is above a first threshold, and generating a control PDU that includes a binary value set to 1 when resource use of the access terminal is below a second threshold.

14. The wireless communications apparatus of claim 11, wherein the memory further retains instructions related to determining an average detected downlink data transmission rate experienced by the access terminal in a given time window, identifying a preferred downlink data transmission rate for the access terminal, generating a first type of control PDU that includes a first selected value corresponding to a percentage decrease from the average detected downlink data transmission rate to the preferred downlink data transmission rate when the preferred downlink data transmission rate is less than the average detected downlink data transmission rate, and generating a second type of control PDU that includes a second selected value corresponding to a percentage increase from the average detected downlink data transmission rate to the preferred downlink data transmission rate when the preferred downlink data transmission rate is greater than the average detected downlink data transmission rate.

15. The wireless communications apparatus of claim 11, wherein the memory further retains instructions related to determining an updated downlink data transmission rate to be utilized by a base station for subsequent transmission for the access terminal, comparing the updated downlink data transmission rate to a previously signaled downlink data transmission rate to be utilized by the base station, generating a first type of MAC control PDU that includes a first selected value corresponding to a percentage decrease from the previously signaled downlink data transmission rate to the updated downlink data transmission rate when the updated downlink data transmission rate is less than the previously signaled downlink data transmission rate, and generating a second type of MAC control PDU that includes a second selected value corresponding to a percentage increase from the previously signaled downlink data transmission rate to the updated downlink data transmission rate when the updated downlink data transmission rate is greater than the previously signaled downlink data transmission rate.

16. The wireless communications apparatus of claim 11, wherein the control PDU indicates at least one of a highest Packet Data Convergence Protocol (PDCP) Sequence Number (SN), a highest Count-C which includes Hyper Frame Number (HFN) plus DPCP SN, or a part of a Count-C permitted to be transmitted by the base station.

17. The wireless communications apparatus of claim 11, wherein the control PDU indicates a maximum number of Packet Data Convergence Protocol (PDCP) PDUs allowed to be transmitted by the base station in a Transmission Time Interval (TTI).

18. The wireless communications apparatus of claim 11, wherein the control PDU switches an associated Packet Data Convergence Protocol (PDCP) bearer between an on state and an off state.

19. A wireless communications apparatus that enables providing flow control feedback to a base station using control protocol data units (PDUs) in a wireless communication environment, comprising:

means for tracking resource utilization associated with an access terminal;

means for yielding a control PDU as a function of the resource utilization associated with the access terminal; and

means for transmitting the control PDU to a base station to control a downlink data transmission rate.

20. The wireless communications apparatus of claim 19, wherein the control PDU is a Media Access Control (MAC) control PDU.

21. The wireless communications apparatus of claim 20, further comprising:

means for yielding a type 1 MAC control PDU when resource utilization of the access terminal is determined to be above a first threshold; and

means for yielding a type 2 MAC control PDU when resource utilization of the access terminal is determined to be below a second threshold.

22. The wireless communications apparatus of claim 20, further comprising:

means for yielding a type 1 MAC control PDU that includes a binary value set to a first value when resource utilization of the access terminal is determined to be above a first threshold; and

means for yielding a type 1 MAC control PDU that includes a binary value set to a second value when resource utilization of the access terminal is determined to be below a second threshold.

23. The wireless communications apparatus of claim 20, further comprising:

means for determining an average detected downlink data transmission rate experienced by the access terminal in a given time window;

means for identifying a preferred downlink data transmission rate for the access terminal as a function of the monitored resource utilization;

means for yielding a type 1 MAC control PDU that includes a first selected value corresponding to a percentage decrease from the average detected downlink data transmission rate to the preferred downlink data transmission rate when the preferred downlink data transmission rate is less than the average detected downlink data transmission rate; and

means for yielding a type 2 MAC control PDU that includes a second selected value corresponding to a percentage increase from the average detected downlink data transmission rate to the preferred downlink data transmission rate when the preferred downlink data transmission rate is greater than the average detected downlink data transmission rate.

24. The wireless communications apparatus of claim 20, further comprising:

means for determining an updated downlink data transmission rate to be utilized by a base station for subsequent transmission for the access terminal based upon the monitored resource utilization;

means for comparing the updated downlink data transmission rate to a previously signaled downlink data transmission rate to be utilized by the base station;

means for yielding a type 1 MAC control PDU that includes a first selected value corresponding to a percentage decrease from the previously signaled downlink data transmission rate to the updated downlink data transmission rate when the updated downlink data transmission rate is less than the previously signaled downlink data transmission rate; and

means for yielding a type 2 MAC control PDU that includes a second selected value corresponding to a percentage increase from the previously signaled downlink data transmission rate to the updated downlink data transmission rate when the updated downlink data transmission rate is greater than the previously signaled downlink data transmission rate.

25. The wireless communications apparatus of claim 19, wherein the control PDU is a Packet Data Convergence Protocol (PDCP) control PDU.

26. The wireless communications apparatus of claim 25, wherein the PDCP control PDU indicates at least one of a highest PDCP Sequence Number (SN) permitted to be transmitted by the base station, a highest Count-C which includes Hyper Frame Number (HFN) plus PDCP SN permitted to be transmitted by the base station, a portion of a Count-C permitted to be transmitted by the base station, or a maximum number of PDCP PDUs allowed to be transmitted by the base station in a Transmission Time Interval (TTI),

27. The wireless communications apparatus of claim 25, wherein the PDCP control PDU switches an associated PDCP bearer between an on state and an off state.

28. A computer program product, comprising:

a computer-readable medium comprising;

code for generating a control protocol data unit (PDU) based upon detected resource use associated with an access terminal; and

code for transmitting the control PDU to a base station to control a downlink data transmission rate.

29. The computer program product of claim 28, wherein the computer-readable medium further comprises:

code for generating a first type of control PDU when resource use of the access terminal is above a first threshold; and

code for generating a second type of control PDU when resource use of the access terminal is below a second threshold.

30. The computer program product of claim 28, wherein the computer-readable medium further comprises:

code for generating a control PDU that includes a binary value set to 0 when resource use of the access terminal is above a first threshold; and

code for generating a control PDU that includes a binary value set to 1 when resource use of the access terminal is below a second threshold.

31. The computer program product of claim 28, wherein the computer-readable medium further comprises:

code for determining an average detected downlink data transmission rate experienced by the access terminal in a given time window;

code for identifying a preferred downlink data transmission rate for the access terminal;

code for generating a first type of control PDU that includes a first selected value corresponding to a percentage decrease from the average detected downlink data transmission rate to the preferred downlink data transmission rate when the preferred downlink data transmission rate is less than the average detected downlink data transmission rate; and

code for generating a second type of control PDU that includes a second selected value corresponding to a percentage increase from the average detected downlink data transmission rate to the preferred downlink data transmission rate when the preferred downlink data transmission rate is greater than the average detected downlink data transmission rate.

32. The computer program product of claim 28, wherein the computer-readable medium further comprises:

code for determining an updated downlink data transmission rate to be utilized by a base station for subsequent transmission for the access terminal;

code for comparing the updated downlink data transmission rate to a previously signaled downlink data transmission rate to be utilized by the base station;

code for generating a first type of MAC control PDU that includes a first selected value corresponding to a percentage decrease from the previously signaled downlink data transmission rate to the updated downlink data transmission rate when the updated downlink data transmission rate is less than the previously signaled downlink data transmission rate; and

code for generating a second type of MAC control PDU that includes a second selected value corresponding to a percentage increase from the previously signaled downlink data transmission rate to the updated downlink data transmission rate when the updated downlink data transmission rate is greater than the previously signaled downlink data transmission rate.

33. The computer program product of claim 28, wherein the control PDU indicates one or more of a highest Packet Data Convergence Protocol (PDCP) Sequence Number (SN) permitted to be transmitted by the base station, a highest Count-C which includes Hyper Frame Number (HFN) plus PDCP SN allowed to be transmitted by the base station, a portion of a Count-C permitted to be transmitted by the base station, or a maximum number of PDCP PDUs allowed to be transmitted by the base station in a Transmission Time Interval (TTI).

34. The computer program product of claim 28, wherein the control PDU switches an associated Packet Data Convergence Protocol (PDCP) bearer between an on state and an off state.

35. A method that facilitates providing downlink flow control in a wireless communication environment, comprising:

detecting a level of resource utilization associated with an access terminal;

generating a channel quality indicator (CQI) report that includes a value selected as a function of the level of resource utilization associated with the access terminal; and

transmitting the CQI report that includes the selected value to a base station to control a downlink data transmission rate.

36. The method of claim 35, further comprising:

selecting a first flow control code word for inclusion in the CQI report to reduce the downlink data transmission rate employed by the base station, the first flow control code word being reserved in CQI code space; and

selecting a second flow control code word for inclusion in the CQI report to increase the downlink data transmission rate employed by the base station, the second flow control code word being reserved in CQI code space.

37. The method of claim 35, further comprising selecting a flow control code word for inclusion in the CQI report to reduce the downlink data transmission rate employed by the base station for a predetermined period of time, the flow control code word being reserved in CQI code space.

38. The method of claim 35, further comprising transmitting the CQI report that includes the selected value to the base station during a corresponding flow control reporting interval, wherein every Xth CQI reporting interval is a flow control reporting interval and X is an integer.

39. The method of claim 38, further comprising:

selecting a predetermined value as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization exceeds a threshold; and

selecting a measured CQI value that is dependent upon channel conditions as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization is below the threshold.

40. The method of claim 38, further comprising:

selecting a resource dependent CQI value, which is a measured CQI value that is dependent upon channel conditions reduced by a factor corresponding to the level of resource utilization, as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization exceeds a threshold; and

selecting the measured CQI value as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization is below the threshold.

41. A wireless communications apparatus, comprising:

a memory that retains instructions related to detecting a level of resource utilization associated with an access terminal, generating a channel quality indicator (CQI) report that includes a value selected as a function of the level of resource utilization associated with the access terminal, and transmitting the CQI report that includes the selected value to a base station to control a downlink data transmission rate; and

a processor, coupled to the memory, configured to execute the instructions retained in the memory.

42. The wireless communications apparatus of claim 41, wherein the memory further retains instructions related to selecting a first flow control code word for inclusion in the CQI report to reduce the downlink data transmission rate employed by the base station, and selecting a second flow control code word for inclusion in the CQI report to increase the downlink data transmission rate employed by the base station, the first flow control code word and the second flow control code word being reserved in CQI code space.

43. The wireless communications apparatus of claim 41, wherein the memory further retains instructions related to selecting a flow control code word for inclusion in the CQI report to reduce the downlink data transmission rate employed by the base station for a predetermined period of time, the flow control code word being reserved in CQI code space.

44. The wireless communications apparatus of claim 41, wherein the memory further retains instructions related to transmitting the CQI report that includes the selected value to the base station during a corresponding flow control reporting interval, wherein every Xth CQI reporting interval is a flow control reporting interval and X is an integer.

45. The wireless communications apparatus of claim 44, wherein the memory further retains instructions related to selecting a predetermined value as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization exceeds a threshold, and selecting a measured CQI value that is dependent upon channel conditions as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization is below the threshold.

46. The wireless communications apparatus of claim 44, wherein the memory further retains instructions related to selecting a resource dependent CQI value, which is a measured CQI value that is dependent upon channel conditions reduced by a factor corresponding to the level of resource utilization, as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization exceeds a threshold, and selecting the measured CQI value as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization is below the threshold.

47. A wireless communications apparatus that enables yielding flow control feedback to a base station using channel quality indicator (CQI) reports in a wireless communication environment, comprising:

means for detecting resource utilization associated with an access terminal;

means for yielding a CQI report that includes a value selected as a function of the resource utilization associated with the access terminal; and

means for sending the CQI report that includes the selected value to a base station to control a downlink data transmission rate.

48. The wireless communications apparatus of claim 47, further comprising:

means for selecting a first flow control code word for inclusion in the CQI report to reduce the downlink data transmission rate employed by the base station, the first flow control code word being reserved in CQI code space; and

means for selecting a second flow control code word for inclusion in the CQI report to increase the downlink data transmission rate employed by the base station, the second flow control code word being reserved in CQI code space.

49. The wireless communications apparatus of claim 47, further comprising means for selecting a flow control code word for inclusion in the CQI report to reduce the downlink data transmission rate employed by the base station for a predetermined period of time, the flow control code word being reserved in CQI code space.

50. The wireless communications apparatus of claim 47, further comprising means for sending the CQI report that includes the selected value to the base station during a corresponding flow control reporting interval, wherein reporting intervals included in a predetermined subset of CQI reporting intervals are used as a flow control reporting intervals.

51. The wireless communications apparatus of claim 50, further comprising:

means for selecting a predetermined value as the value for inclusion in the CQI report to be sent during the corresponding flow control reporting interval when the level of resource utilization exceeds a threshold; and

means for selecting a measured CQI value that is dependent upon channel conditions as the value for inclusion in the CQI report to be sent during the corresponding flow control reporting interval when the level of resource utilization is below the threshold.

52. The wireless communications apparatus of claim 50, further comprising:

means for selecting a resource dependent CQI value, which is a measured CQI value that is dependent upon channel conditions reduced by a factor corresponding to the level of resource utilization, as the value for inclusion in the CQI report to be sent during the corresponding flow control reporting interval when the level of resource utilization exceeds a threshold; and

means for selecting the measured CQI value as the value for inclusion in the CQI report to be sent during the corresponding flow control reporting interval when the level of resource utilization is below the threshold.

53. A computer program product, comprising:

a computer-readable medium comprising;

code for detecting a level of resource utilization associated with an access terminal;

code for generating a channel quality indicator (CQI) report that includes a value selected as a function of the level of resource utilization associated with the access terminal; and

code for transmitting the CQI report that includes the selected value to a base station to control a downlink data transmission rate.

54. The computer program product of claim 53, wherein the computer-readable medium further comprises:

code for selecting a first flow control code word for inclusion in the CQI report to reduce the downlink data transmission rate employed by the base station, the first flow control code word being reserved in CQI code space; and

code for selecting a second flow control code word for inclusion in the CQI report to increase the downlink data transmission rate employed by the base station, the second flow control code word being reserved in CQI code space.

55. The computer program product of claim 53, wherein the computer-readable medium further comprises code for selecting a flow control code word for inclusion in the CQI report to reduce the downlink data transmission rate employed by the base station for a predetermined period of time, the flow control code word being reserved in CQI code space.

56. The computer program product of claim 53, wherein the computer-readable medium further comprises code for transmitting the CQI report that includes the selected value to the base station during a corresponding flow control reporting interval, wherein every Xth CQI reporting interval is a flow control reporting interval and X is an integer.

57. The computer program product of claim 56, wherein the computer-readable medium further comprises:

code for selecting a predetermined value as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization exceeds a threshold; and

code for selecting a measured CQI value that is dependent upon channel conditions as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization is below the threshold.

58. The computer program product of claim 56, wherein the computer-readable medium further comprises:

code for selecting a resource dependent CQI value, which is a measured CQI value that is dependent upon channel conditions reduced by a factor corresponding to the level of resource utilization, as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization exceeds a threshold; and

code for selecting the measured CQI value as the value for inclusion in the CQI report to be transmitted during the corresponding flow control reporting interval when the level of resource utilization is below the threshold.

59. A method that facilitates controlling a downlink data transmission rate for an access terminal based upon flow control feedback from the access terminal in a wireless communication environment, comprising:

receiving a control protocol data unit (PDU) that provides flow control feedback from an access terminal;

analyzing the control PDU to recognize the flow control feedback; and

adjusting a downlink data transmission rate for the access terminal based upon the flow control feedback provided by the control PDU.

60. The method of claim 59, further comprising adjusting the downlink data transmission rate based upon at least one of an identified type of the control PDU or a binary value recognized as being included in the control PDU.

61. The method of claim 59, further comprising:

determining whether to increase or decrease the downlink data transmission rate as a function of an identified type of the control PDU; and

adjusting the downlink data transmission rate by a percentage controlled by an integer value recognized from the control PDU.

62. A wireless communications apparatus, comprising:

a memory that retains instructions related to receiving a channel quality indicator (CQI) report that includes a value corresponding to flow control feedback from an access terminal, evaluating the value included in the CQI report to determine the flow control feedback, and adjusting a downlink data transmission rate for the access terminal based upon the flow control feedback provided by the CQI report; and

a processor, coupled to the memory, configured to execute the instructions retained in the memory.

63. The wireless communications apparatus of claim 62, wherein the memory further retains instructions related to recognizing whether the value included in the CQI report is a flow control code word that is reserved in CQI code space to indicate whether the access terminal is congested.

64. The wireless communications apparatus of claim 62, wherein the memory further retains instructions related to recognizing a resource dependent CQI value, which indicates a degree of congestion experienced by the access terminal.

65. A wireless communications apparatus that enables altering a downlink data transmission rate employing flow control feedback in a wireless communication environment, comprising:

means for obtaining a channel quality indicator (CQI) report that includes a value corresponding to flow control feedback from an access terminal;

means for analyzing the value included in the CQI report to identify the flow control feedback; and

means for modifying a downlink data transmission rate for the access terminal based upon the flow control feedback provided by the CQI report.

66. The wireless communications apparatus of claim 65, further comprising means for recognizing whether the value included in the CQI report is a flow control code word that is reserved in CQI code space to indicate whether the access terminal is congested.

67. The wireless communications apparatus of claim 65, further comprising means for recognizing a resource dependent CQI value, which indicates a degree of congestion experienced by the access terminal.

68. A computer program product, comprising:

a computer-readable medium comprising;

code for obtaining a control protocol data unit (PDU) that provides flow control feedback from an access terminal;

code for evaluating the control PDU to identify the flow control feedback; and

code for altering a downlink data transmission rate for the access terminal based upon the flow control feedback provided by the control PDU.

69. The computer program product of claim 68, wherein the computer-readable medium further comprises code for altering the downlink data transmission rate based upon at least one of an identified type of the control PDU or a binary value recognized as being included in the control PDU.

70. The computer program product of claim 68, wherein the computer-readable medium further comprises:

code for determining whether to increase or decrease the downlink data transmission rate as a function of an identified type of the control PDU; and

code for adjusting the downlink data transmission rate by a percentage controlled by an integer value recognized from the control PDU.