Wireless local area network apparatus

• US 20020131484A1
• Filed: 03/07/2002
• Published: 09/19/2002
• Est. Priority Date: 03/06/1993
• Status: Active Grant

• Current Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Diepstraten, Wilhelmus J. M., Bokhorst, Hendrik van, Driest, Hans van
• Granted Patent: US 6,707,867 B2
• Time in Patent Office: Days
• US Class Current: 375/222
• CPC Class Codes: H04L 27/04 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 7/04 Speed or phase control by synchronisation signals H04L7/0075 takes precedence
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 56/009 Closed loop measurements
• CPC Class Codes: H04W 76/27 Transitions between radio resource control [RRC] states
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/022 Selective call receivers
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A wireless local area network apparatus includes a transmitter and a receiver in which operation of the receiver is accurately synchronized with periodic signals from the transmitter. The periodic signals contain timing data indicating the state of a timer in the transmitter at the time the signal containing that data was transmitted and this timing data is retrieved from the signal when received by the receiver and loaded in a timer for controlling operation of the receiver.

Claims

1. A method of transmitting data from a transmitter having a timer and a modem, comprising:

periodically transmitting a transmission signal that includes a traffic pending field and a timestamp field,

the timestamp field including a timestamp for synchronizing a receiver timer with the transmitter timer, wherein the timestamp accounts for delays in the transmitter modem.

2. The method of claim 1, wherein the timestamp represents a value within a count sequence of the transmitter timer at a time of transmission of the transmission signal.

3. The method of claim 1, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

4. The method of claim 1, wherein the transmission signal further includes a timer interval field, and the timer interval field includes timer interval data indicating an interval between periodic transmissions of transmission signals including traffic pending fields.

5. The method of claim 1, wherein the transmission signal further includes a broadcast pending field including broadcast pending data indicating whether broadcast data is buffered at the transmitter.

6. The method of claim 1, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

7. A method of transmitting data from a transmitter having a timer, comprising:

periodically transmitting a transmission signal that includes a header field, a traffic pending field, and a timestamp field, such that the header field is transmitted before the traffic pending field and before the timestamp field, and

loading, when the transmission of the header field begins, a timestamp into the timestamp field of the transmission signal, wherein the timestamp represents a value within a count sequence of the transmitter timer at a time of transmission of the transmission signal.

8. The method of claim 7, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

9. The method of claim 7, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

10. The method of claim 7, wherein the header field is the first field of the transmission signal such that the loading of the timestamp field with the timestamp occurs when the transmission of the transmission signal begins.

11. The method of claim 7, wherein the header field includes type data indicating a type of the transmission signal.

13. The method of claim 12, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

14. The method of claim 12, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

15. The method of claim 12, wherein the timestamp represents a value within a count sequence of the transmitter timer at a time of transmission of the transmission signal.

16. The method of claim 12, wherein the protocol is a carrier sense multiple access with collision avoidance protocol.

18. The method of claim 17, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

19. The method of claim 17, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

12. A method of transmitting data from a transmitter in a wireless local area network, comprising:

periodically generating a transmission signal that includes a traffic pending field and a timestamp field,

running a protocol to determine whether the network is busy, loading a timestamp into the timestamp field of the transmission signal if the running step determines the network is not busy, and

transmitting the transmission signal if the running step determines that the network is not busy.

17. A method of transmitting data from a transmitter having a timer and a modem, comprising:

periodically transmitting a transmission signal that includes a header field, a traffic pending field, and a timestamp field, such that the header field is transmitted before the traffic pending field and before the timestamp field, and

loading, when the transmission of the header field begins, a timestamp into the timestamp field of the transmission signal, the timestamp for synchronizing a receiver timer with the transmitter timer, wherein the timestamp accounts for delays in the transmitter modem.

20. A method of transmitting data from a transmitter having a timer and a modem in a wireless local area network, comprising:

periodically generating a transmission signal that includes a traffic pending field and a timestamp field,

running a protocol to determine whether the network is busy,

loading a timestamp into the timestamp field of the transmission signal if the running step determines the network is not busy, wherein the timestamp can be used for synchronizing a receiver timer with the transmitter timer and wherein the timestamp accounts for delays in the transmitter modem, and

transmitting the transmission signal if the running step determines that the network is not busy.

21. The method of claim 20, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

22. The method of claim 20, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

24. The method of claim 23, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

26. The method of claim 25, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

28. The transmitter of claim 27, wherein the timestamp represents a value within a count sequence of the transmitter timer at a time of transmission of the transmission signal.

29. The transmitter of claim 27, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

30. The transmitter of claim 27, wherein the transmission signal further includes a timer interval field, and the timer interval field includes timer interval data indicating an interval between periodic transmissions of transmission signals including traffic pending fields.

31. The transmitter of claim 27, wherein the transmission signal further includes a broadcast pending field including broadcast pending data indicating whether broadcast data is buffered at the transmitter.

32. The transmitter of claim 27, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

23. A method of transmitting data from a transmitter having a timer in a wireless local area network, comprising:

periodically generating a transmission signal that includes a header field, a traffic pending field, and a timestamp field, such that the header field is transmitted before the traffic pending field and before the timestamp field,

running a protocol to determine whether the network is busy,

transmitting the transmission signal if the running step determines that the network is not busy, and

loading, when the transmission of the header field begins, a timestamp into the timestamp field of the transmission signal, wherein the timestamp represents a value within a count sequence of the transmitter timer at a time of transmission of the transmission signal.

25. A method of transmitting data from a transmitter having a timer and a modem in a wireless local area network, comprising:

periodically generating a transmission signal that includes a header field, a traffic pending field, and a timestamp field, such that the header field is transmitted before the traffic pending field and before the timestamp field,

running a protocol to determine whether the network is busy,

transmitting the transmission signal if the running step determines that the network is not busy, and

loading, when the transmission of the header field begins, a timestamp into the timestamp field of the transmission signal, wherein the timestamp can be used for synchronizing a receiver timer with the transmitter timer and wherein the timestamp accounts for delays in the transmitter modem.

27. A transmitter comprising:

a timer,

a modem, and

a controller controlling the modem to periodically transmit a transmission signal that includes a traffic pending field and a timestamp field, the timestamp field including a timestamp for synchronizing a receiver timer with the transmitter timer, wherein the timestamp accounts for delays in the transmitter modem.

33. A transmitter, comprising:

a timer,

a controller controlling operation of the transmitter to periodically transmit a transmission signal that includes a header field, a traffic pending field, and a timestamp field, such that the header field is transmitted before the traffic pending field and before the timestamp field, and controls loading, when the transmission of the header field begins, of a timestamp into the timestamp field of the transmission signal, wherein the timestamp represents a value within a count sequence of the transmitter timer at a time of transmission of the transmission signal.

34. The transmitter of claim 33, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

35. The transmitter of claim 33, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

36. The transmitter of claim 33, wherein the header field is the first field of the transmission signal such that the loading of the timestamp field with the timestamp occurs when the transmission of the transmission signal begins.

37. The transmitter of claim 33, wherein the header field includes type data indicating a type of the transmission signal.

39. The transmitter of claim 38, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

40. The transmitter of claim 38, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

41. The transmitter of claim 38, further comprising:

a timer, and wherein

the timestamp represents a value within a count sequence of the transmitter timer at a time of transmission of the transmission signal.

42. The transmitter of claim 38, wherein the protocol is a carrier sense multiple access with collision avoidance protocol.

38. A transmitter in a wireless local area network, comprising:

a controller controlling periodic generation a transmission signal that includes a traffic pending field and a timestamp field, running a protocol to determine whether the network is busy, controlling loading of a timestamp into the timestamp field of the transmission signal if the running step determines the network is not busy, and controlling the transmitter to transmit the transmission signal if the running step determines that the network is not busy.

43. A transmitter, comprising:

a timer,

a modem,

a controller controlling periodically transmission of a transmission signal that includes a header field, a traffic pending field, and a timestamp field, such that the header field is transmitted before the traffic pending field and before the timestamp field, and controlling loading, when the transmission of the header field begins, of a timestamp into the timestamp field of the transmission signal, the timestamp for synchronizing a receiver timer with the transmitter timer, wherein the timestamp accounts for delays in the transmitter modem.

44. The transmitter of claim 43, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

45. The transmitter of claim 43, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

47. The transmitter of claim 46, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

48. The transmitter of claim 46, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

50. The transmitter of claim 49, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

46. A transmitter in a wireless local area network, comprising:

a timer,

a modem,

a controller controlling periodic generation of a transmission signal that includes a traffic pending field and a timestamp field, running a protocol to determine whether the network is busy, controlling loading of a timestamp into the timestamp field of the transmission signal if the running step determines the network is not busy, wherein the timestamp can be used for synchronizing a receiver timer with the transmitter timer and wherein the timestamp accounts for delays in the transmitter modem, and controlling the modem to transmit the transmission signal if the running step determines that the network is not busy.

49. A transmitter in a wireless local area network, comprising

a timer,

a controller controlling periodic generation of a transmission signal that includes a header field, a traffic pending field, and a timestamp field, such that the header field is transmitted before the traffic pending field and before the timestamp field, running a protocol to determine whether the network is busy, controlling the transmitter to transmit the transmission signal if the running step determines that the network is not busy, and controlling loading, when the transmission of the header field begins, of a timestamp into the timestamp field of the transmission signal, wherein the timestamp represents a value within a count sequence of the transmitter timer at a time of transmission of the transmission signal.

51. A transmitter in a wireless local area network, comprising:

a timer,

a modem,

a controller controlling periodic generation of a transmission signal that includes a header field, a traffic pending field, and a timestamp field, such that the header field is transmitted before the traffic pending field and before the timestamp field, running a protocol to determine whether the network is busy, controlling the modem to transmit the transmission signal if the running step determines that the network is not busy, and controlling loading, when the transmission of the header field begins, of a timestamp into the timestamp field of the transmission signal, wherein the timestamp can be used for synchronizing a receiver timer with the transmitter timer and wherein the timestamp accounts for delays in the transmitter modem.

52. The transmitter of claim 51, wherein the transmission signal is periodically transmitted over a wireless local area network by an access point that is connected to a backbone infrastructure.

53. A method of synchronizing a receiver with a transmitter in a wireless local area network, comprising:

periodically receiving a transmission signal from a transmitter, the transmission signal including a traffic pending field and a timestamp field, the timestamp field including a timestamp for synchronizing a receiver timer with the transmitter timer, wherein the timestamp accounts for delays in the transmitter modem, and

synchronizing the receiver with the transmitter based on the timestamp.

54. The method of claim 53, wherein the synchronizing step comprises:

commencing a synchronizing count sequence beginning at a value equal to the timestamp; and

synchronizing the receiver with the synchronizing count sequence when the transmission signal has been properly received.

55. The method of claim 54, wherein the synchronizing the receiver with the synchronizing count sequence step adjusts a count value at a receiver timer equal to a current count value in the synchronizing count sequence.

56. The method of claim 55, further comprising:

periodically waking the receiver from a sleep mode to receive transmissions based on output from the receiver timer.

57. The method of claim 55, further comprising:

controlling a frequency hopping operation based on output from the receiver timer.

58. The method of claim 53, wherein the timestamp represents a value within a count sequence of the transmitter timer at a time of transmission of the transmission signal.

59. The method of claim 53, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

60. The method of claim 53, wherein the transmission signal further includes a timer interval field, and the timer interval field includes timer interval data indicating an interval between periodic transmissions of transmission signals including traffic pending fields.

61. The method of claim 53, wherein the transmission signal further includes a broadcast pending field including broadcast pending data indicating whether data is buffered at an access point including the transmitter.

62. The method of claim 53, wherein the transmission signal further includes a header field, which is transmitted before the timestamp field and the traffic pending field.

63. The method of claim 62, wherein the header field includes type data indicating a type of the transmission signal.

64. A receiver, comprising:

a radio modem periodically receiving a transmission signal from a transmitter, the transmission signal including a traffic pending field and a timestamp field, the timestamp field including a timestamp for synchronizing a receiver timer with the transmitter timer, wherein the timestamp accounts for delays in the transmitter modem, and

synchronizing circuitry synchronizing the receiver with the transmitter based on the timestamp.

65. The receiver of claim 64, wherein the synchronizing circuitry comprises:

a counter commencing a synchronizing count sequence beginning at a value equal to the timestamp; and

wherein

the synchronizing circuitry synchronizes the receiver with the synchronizing count sequence when the transmission signal has been properly received.

66. The receiver of claim 65, wherein the synchronizing circuitry further comprises:

the receiver timer, and the synchronizing circuitry adjusts a count value at a receiver timer equal to a current count value in the synchronizing count sequence.

67. The receiver of claim 66, further comprising:

a wake-up controller periodically waking the receiver from a sleep mode to receive transmissions based on output from the receiver timer.

68. The receiver of claim 66, further comprising:

frequency change controller controlling a frequency hopping operation based on output from the receiver timer.

69. The receiver of claim 64, wherein the timestamp represents a value within a count sequence of the transmitter timer at a time of transmission of the transmission signal.

70. The receiver of claim 64, wherein the traffic pending field includes data indicating stations for which the transmitter has data buffered.

71. The receiver of claim 64, wherein the transmission signal further includes a timer interval field, and the timer interval field includes timer interval data indicating an interval between periodic transmissions of transmission signals including traffic pending fields.

72. The receiver of claim 64, wherein the transmission signal further includes a broadcast pending field including broadcast pending data indicating whether data is buffered at an access point including the transmitter.

73. The receiver of claim 64, wherein the transmission signal further includes a header field, which is transmitted before the timestamp field and the traffic pending field.

74. The receiver of claim 73, wherein the header field includes type data indicating a type of the transmission signal.