Transmitter adjustment based on transmission statistics

• US 7,418,054 B2
• Filed: 06/19/2003
• Issued: 08/26/2008
• Est. Priority Date: 11/04/2002
• Status: Active Grant

• Current Assignee: Advanced Micro Devices, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Grell, Michael, Eckhardt, Uwe, Lenk, Matthias
• Primary Examiner(s): Ghebretinsae; Temesghen
• Application Number:
  US10/464,990
• Publication Number:
  US 20040086058A1
• Time in Patent Office: 1,895 Days
• Field of Search: 375/295, 375/224, 375/228, 375/296, 375/309, 370/245, 370/242, 370/241
• US Class Current: 375/295
• CPC Class Codes: H04L 25/05 Electric or magnetic storage of signals before transmitting or retransmitting for changing the transmission rate
• CPC Class Codes: H04W 52/08 Closed loop power control

Abstract

A WLAN (Wireless Local Area Network) transmitter or another data communications apparatus is provided that includes a transmission section that is configured to generate signals to be transmitted, and a control section that is connected to the transmission section to control the transmission section dependent on at least two transmission parameters. The control section comprises a state transition controller that is configured to step through a plurality of predefined control states. The control section is configured to apply different transmission parameter modification mechanisms in different control states. The state transition controller is configured to determine the respective next control states based on transmission success and failure statistics.

Claims

1. A WLAN (Wireless Local Area Network) transmitter comprising:

a transmission section configured to generate signals to be transmitted; and

a control section connected to said transmission section to control said transmission section dependent on at least two transmission parameters, said control section comprising a state transition controller configured to step through a plurality of predefined control states, wherein said at least two transmission parameters comprise an RTS/CTS (Request to Send/Clear to Send) threshold value to be used for determining whether or not to activate an RTS/CTS mechanism, and at least one of said transmission parameter modification mechanisms is an RTS/CTS threshold adaptation mechanism,

wherein said control section is configured to apply different transmission parameter modification mechanisms in different ones of the plurality of predefined control states, and

wherein said state transition controller is configured to determine a respective next one of the plurality of predefined control states based on a value indicative of whether a transmission attempt has succeeded or failed.

2. The WLAN transmitter of claim 1, wherein said at least two transmission parameters comprise a transmission data rate and at least one of said transmission parameter modification mechanisms is a data rate adaptation mechanism.

3. The WLAN transmitter of claim 2, wherein said data rate adaptation mechanism is configured to modify the data rate by selecting a different one of a given set of predefined data rate values.

4. The WLAN transmitter of claim 3, wherein said transmission section is configured to generate BPSK (Binary Phase Shift Keying) signals, and one of said given set of predefined data rate values is 1 Mbps.

5. The WLAN transmitter of claim 3, wherein said transmission section is configured to generate QPSK (Quadrature Phase Shift Keying) signals, and one of said given set of predefined data rate values is 2 Mbps.

6. The WLAN transmitter of claim 3, wherein said transmission section is configured to generate CCK (Complementary Code Keying) signals, and one of said given set of predefined data rate values is 5.5 Mbps.

7. The WLAN transmitter of claim 3, wherein said transmission section is configured to generate CCK (Complementary Code Keying) signals, and one of said given set of predefined data rate values is 11 Mbps.

8. The WLAN transmitter of claim 2, wherein said plurality of predefined control states comprises a data rate increase state in which said control section is configured to increase the data rate.

9. The WLAN transmitter of claim 2, wherein said plurality of predefined control states comprises a data rate decrease state in which said control section is configured to decrease the data rate.

10. The WLAN transmitter of claim 2, wherein said plurality of predefined control states comprises at least one state in which said control section is configured to keep the data rate constant.

11. The WLAN transmitter of claim 1, wherein said at least two transmission parameters comprise a transmission power and at least one of said transmission parameter modification mechanisms is a transmission power adaptation mechanism.

12. The WLAN transmitter of claim 11, wherein said plurality of predefined control states comprises a transmission power increase state in which said control section is configured to increase the transmission power.

13. The WLAN transmitter of claim 12, wherein said plurality of predefined control states further comprises a transmission power decrease state in which said control section is configured to decrease the transmission power, wherein said state transition controller is configured to prevent from toggling from said transmission power increase state to said transmission power decrease state.

14. The WLAN transmitter of claim 11, wherein said plurality of predefined control states comprises a transmission power decrease state in which said control section is configured to decrease the transmission power.

15. The WLAN transmitter of claim 11, wherein said plurality of predefined control states comprises at least one state in which said control section is configured to keep the transmission power constant.

16. The WLAN transmitter of claim 11, wherein said state transition controller is capable of being instructed by means of a control signal to temporarily disable said transmission power adaptation mechanism.

17. The WLAN transmitter of claim 1, wherein said RTS/CTS threshold is a frame length limit, and said RTS/CTS mechanism is activated if the current frame length exceeds that limit.

18. The WLAN transmitter of claim 1, wherein said plurality of predefined control states comprises an RTS/CTS mechanism activation state in which said control section is configured to activate said RTS/CTS mechanism.

19. The WLAN transmitter of claim 18, wherein said control section comprises a register storing a fall back count value that is continuously increased as long as said state transition controller is in said RTS/CTS mechanism activation state, said fall back count value indicating the time duration for which said RTS/CTS mechanism is already active.

20. The WLAN transmitter of claim 19, wherein said state transition controller is configured to repetitively compare said fall back count value with a fall back limit value and leave said RTS/CTS mechanism activation state if said fall back limit value is reached.

21. The WLAN transmitter of claim 1, wherein said plurality of predefined control states comprises at least one state in which said control section is configured to deactivate said RTS/CTS mechanism.

22. The WLAN transmitter of claim 1, wherein said state transition controller is capable of being instructed by means of a control signal to temporarily disable said RTS/CTS threshold adaptation mechanism.

23. The WLAN transmitter of claim 1, wherein said plurality of predefined control states comprises a constant state in which said control section is configured to apply no transmission parameter modification mechanism at all.

24. The WLAN transmitter of claim 23, wherein said plurality of predefined control states further comprises a transmission power increase state in which said control section is configured to increase the transmission power, and a transmission power decrease state in which said control section is configured to decrease the transmission power,

wherein said control section is arranged to freeze a long term filter value when stepping from said transmission power decrease state to said constant state, said long term filter value being generated from a transmission success and failure parameter on a long term basis, and

wherein said state transition controller is configured to step from said constant state to said transmission power increase state dependent on a comparison of the frozen long term filter value and a current long term filter value.

25. The WLAN transmitter of claim 1, wherein said plurality of predefined control states comprises a start-up state which said state transition controller enters in a start-up or reset condition.

26. The WLAN transmitter of claim 1, wherein said transmission parameter modification mechanisms are configured to modify in each control state only one transmission parameter.

27. The WLAN transmitter of claim 1, wherein said control section comprises a short term filter connected to receive a transmission success and failure parameter and adapted to generate a short term filter value therefrom, wherein said state transition controller is configured to determine the respective next control states based on said short term filter value.

28. The WLAN transmitter of claim 27, wherein said state transition controller is configured to control said short term filter to reset its short term filter value when stepping from one control state to the next control state.

29. The WLAN transmitter of claim 28, wherein said plurality of predefined control states comprises at least one state where said reset is disabled if said state is the respective next control state.

30. The WLAN transmitter of claim 27, wherein said transmission success and failure parameter is +1 in case of a successful transmission, and −

1 in case of a transmission failure.

31. The WLAN transmitter of claim 27, wherein said short term filter value is linearly dependent from said transmission success and failure parameter.

32. The WLAN transmitter of claim 27, wherein said at least two transmission parameters comprise a transmission data rate, and said state transition controller is configured to determine the respective next control state based on a comparison of said short term filter value with an upper limit value indicating to increase the data rate if said short term filter value exceeds that upper limit value.

33. The WLAN transmitter of claim 32, wherein said control section further comprises at least one long term filter connected to receive said transmission success and failure parameter and adapted to generate at least one long term filter value therefrom, said upper limit value being modified in each control state based on the respective current long term filter value.

34. The WLAN transmitter of claim 33, wherein said upper limit value is linearly dependent on said long term filter value.

35. The WLAN transmitter of claim 27, wherein said at least two transmission parameters comprise a transmission data rate, and said state transition controller is configured to determine the respective next control state based on a comparison of said short term filter value with a lower limit value indicating to decrease the data rate if said short term filter value falls below that lower limit value.

36. The WLAN transmitter of claim 27, wherein said at least two transmission parameters comprise a transmission power, and said state transition controller is configured to determine the respective next control state based on a comparison of said short term filter value with an upper power limit value indicating to decrease the transmission power if said short term filter value exceeds that upper power limit value.

37. The WLAN transmitter of claim 36, wherein said at least two transmission parameters further comprise a transmission data rate, and said state transition controller is configured to determine the respective next control state also based on a comparison of said short term filter value with an upper data rate limit value indicating to increase the data rate if said short term filter value exceeds that upper data rate limit value, wherein said upper power limit value is greater than said upper data rate limit value.

38. The WLAN transmitter of claim 1, wherein said control section comprises at least one long term filter connected to receive a transmission success and failure parameter and adapted to generate at least one long term filter value therefrom, said at least one long term filter value being modified in each control state based on the respective current transmission success and failure parameter.

39. The WLAN transmitter of claim 38, wherein said at least one long term filter comprises separate long term filters for different transmission data rates.

40. The WLAN transmitter of claim 1, wherein said control section is connected to receive at least one control signal to enable or disable at least one of said transmission parameter modification mechanisms.

41. A data communications apparatus comprising:

a transmission section configured to generate signals to be transmitted; and

a control section connected to said transmission section to control said transmission section dependent on at least two transmission parameters, said control section comprising a state transition controller configured to step through a plurality of predefined control states, wherein said at least two transmission parameters comprise an RTS/CTS (Request to Send/Clear to Send) threshold value to be used for determining whether or not to activate an RTS/CTS mechanism, and at least one of said transmission parameter modification mechanisms is an RTS/CTS threshold adaptation mechanism.

wherein said control section is configured to apply different transmission parameter modification mechanisms in different ones of the plurality of predefined control states, and

wherein said state transition controller is configured to determine a respective next one of the plurality of predefined control states based on a value indicative of whether a transmission attempt has succeeded or failed.

42. An integrated circuit chip for use in a data communications transmitter, said integrated circuit chip comprising:

a transmission circuit configured to generate signals to be transmitted; and

a control circuit connected to said transmission circuit to control said transmission circuit dependent on at least two transmission parameters, said control circuit comprising a state transition control circuit configured to step through a plurality of predefined control states, wherein said at least two transmission parameters comprise an RTS/CTS (Request to Send/Clear to Send) threshold value to be used for determining whether or not to activate an RTS/CTS mechanism, and at least one of said transmission parameter modification mechanisms is an RTS/CTS threshold adaptation mechanism,

wherein said control circuit is configured to apply different transmission parameter modification mechanisms in different ones of the plurality of predefined control states, and

wherein said state transition control circuit is configured to determine a respective next one of the plurality of predefined control states based on a value indicative of whether a transmission attempt has succeeded or failed.

43. A method of operating a data communications device for transmitting data, the method comprising:

controlling the generation of signals to be transmitted, based on at least two transmission parameters, wherein said control comprises;

stepping through a plurality of predefined control states;

applying different transmission parameter modification mechanisms in different ones of the plurality of predefined control states; and

determining a respective next one of the plurality of predefined control states based on a value indicative of whether a transmission attempt has succeeded or failed;

wherein said at least two transmission parameters comprise an RTS/CTS (Request to Send/Clear to Send) threshold value to be used for determining whether or not to activate an RTS/CTS mechanism, and at least one of said transmission parameter modification mechanisms is an RTS/CTS threshold adaptation mechanism; and

wherein the method further comprises transmitting signals generated based on said control.

44. The method of claim 43, wherein said at least two transmission parameters comprise a transmission data rate and at least one of said transmission parameter modification mechanisms is a data rate adaptation mechanism.

45. The method of claim 44, wherein said data rate adaptation mechanism is configured to modify the data rate by selecting a different one of a given set of predefined data rate values.

46. The method of claim 45, wherein said data communications device is configured to generate BPSK (Binary Phase Shift Keying) signals, and one of said given set of predefined data rate values is 1 Mbps.

47. The method of claim 45, wherein said data communications device is configured to generate QPSK (Quadrature Phase Shift Keying) signals, and one of said given set of predefined data rate values is 2 Mbps.

48. The method of claim 45, wherein said data communications device is configured to generate CCK (Complementary Code Keying) signals, and one of said given set of predefined data rate values is 5.5 Mbps.

49. The method of claim 45, wherein said data communications device is configured to generate CCK (Complementary Code Keying) signals, and one of said given set of predefined data rate values is 11 Mbps.

50. The method of claim 44, wherein said plurality of predefined control states comprises a data rate increase state in which the data rate is increased.

51. The method of claim 44, wherein said plurality of predefined control states comprises a data rate decrease state in which the data rate is decreased.

52. The method of claim 44, wherein said plurality of predefined control states comprises at least one state in which the data rate is kept constant.

53. The method of claim 43, wherein said at least two transmission parameters comprise a transmission power and at least one of said transmission parameter modification mechanisms is a transmission power adaptation mechanism.

54. The method of claim 53, wherein said plurality of predefined control states comprises a transmission power increase state in which the transmission power is increased.

55. The method of claim 54, wherein said plurality of predefined control states further comprises a transmission power decrease state in which the transmission power is decreased, wherein no toggling is possible between said transmission power increase state and said transmission power decrease state.

56. The method of claim 53, wherein said plurality of predefined control states comprises a transmission power decrease state in which the transmission power is decreased.

57. The method of claim 53, wherein said plurality of predefined control states comprises at least one state in which the transmission power is kept constant.

58. The method of claim 53, wherein said transmission power adaptation mechanism can temporarily be disabled.

59. The method of claim 43, wherein said RTS/CTS threshold is a frame length limit, and said RTS/CTS mechanism is activated if the current frame length exceeds that limit.

60. The method of claim 43, wherein said plurality of predefined control states comprises an RTS/CTS mechanism activation state in which said RTS/CTS mechanism is activated.

61. The method of claim 60, wherein said control further comprises:

storing a fall back count value; and

continuously updating said fall back count value as long as said RTS/CTS mechanism activation state is active,

wherein said fall back count value indicates the time duration for which said RTS/CTS mechanism is already active.

62. The method of claim 61, wherein said control further comprises:

repetitively comparing said fall back count value with a fall back limit value and leaving said RTS/CTS mechanism activation state if said fall back limit value is reached.

63. The method of claim 43, wherein said plurality of predefined control states comprises at least one state in which said RTS/CTS mechanism is deactivated.

64. The method of claim 43, wherein said RTS/CTS threshold adaptation mechanism can be temporarily disabled.

65. The method of claim 43, wherein said plurality of predefined control states comprises a constant state in which no transmission parameter modification mechanism is applied at all.

66. The method of claim 65, wherein said plurality of predefined control states further comprises a transmission power increase state in which the transmission power is increased, and a transmission power decrease state in which the transmission power is decreased,

wherein said control further comprises freezing a long term filter value when stepping from said transmission power decrease state to said constant state, said long term filter value being generated from a transmission success and failure parameter on a long term basis, and

wherein said stepping is configured to step from said constant state to said transmission power increase state dependent on a comparison of the frozen long term filter value and a current long term filter value.

67. The method of claim 43, wherein said plurality of predefined control states comprises a start-up state which is entered in a start-up or reset condition.

68. The method of claim 43, wherein said transmission parameter modification mechanisms are configured to modify in each control state only one transmission parameter.

69. The method of claim 43, wherein said control further comprises:

operating a short term filter receiving a transmission success and failure parameter and generating a short term filter value therefrom,

wherein the respective next control states are determined based on said short term filter value.

70. The method of claim 69, wherein operating said short term filter comprises:

resetting said short term filter value when stepping from one control state to the next control state.

71. The method of claim 70, wherein said reset is disabled if the respective next control state is a predefined state.

72. The method of claim 69, wherein said transmission success and failure parameter is +1 in case of a successful transmission, and −

1 in case of a transmission failure.

73. The method of claim 69, wherein said short term filter value is linearly dependent from said transmission success and failure parameter.

74. The method of claim 69, wherein said at least two transmission parameters comprise a transmission data rate, and the respective next control state is determined based on a comparison of said short term filter value with an upper limit value indicating to increase the data rate if said short term filter value exceeds that upper limit value.

75. The method of claim 74, wherein said control further comprises:

operating at least one long term filter receiving said transmission success and failure parameter and generating at least one long term filter value therefrom, said upper limit value being modified in each control state based on the respective current long term filter value.

76. The method of claim 75, wherein said upper limit value is linearly dependent on said long term filter value.

77. The method of claim 69, wherein said at least two transmission parameters comprise a transmission data rate, and the respective next control state is determined based on a comparison of said short term filter value with a lower limit value indicating to decrease the data rate if said short term filter value falls below that lower limit value.

78. The method of claim 69, wherein said at least two transmission parameters comprise a transmission power, and the respective next control state is determined based on a comparison of said short term filter value with an upper power limit value indicating to decrease the transmission power if said short term filter value exceeds that upper power limit value.

79. The method of claim 78, wherein said at least two transmission parameters further comprise a transmission data rate, and the respective next control state is determined also on the basis of a comparison of said short term filter value with an upper data rate limit value indicating to increase the data rate if said short term filter value exceeds that upper data rate limit value, wherein said upper power limit value is greater than said upper data rate limit value.

80. The method of claim 43, wherein said control further comprises:

operating at least one long term filter receiving a transmission success and failure parameter and generating at least one long term filter value therefrom, said at least one long term filter value being modified in each control state based on the respective current transmission success and failure parameter.

81. The method of claim 80, wherein said at least one long term filter comprises separate long term filters for different transmission data rates.

82. The method of claim 43, wherein said control further comprises:

receiving at least one control signal to enable or disable at least one of said transmission parameter modification mechanisms.