LAN with message interleaving

• US 20030206535A1
• Filed: 01/22/2003
• Published: 11/06/2003
• Est. Priority Date: 05/06/2002
• Status: Active Grant

• Current Assignee: Allied Telesis Israel Ltd.
• Original Assignee: Extricom Limited (Allied Telesis Holdings KK)
• Inventors: Shpak, Eran
• Granted Patent: US 7,319,688 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 47/245 using preemption
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 92/02 Inter-networking arrangements
• CPC Class Codes: H04W 92/20 between access points

Abstract

A method for mobile communication includes arranging a plurality of access points in a wireless local area network (WLAN) to communicate on a common frequency channel with a mobile station, and linking the access points together by cables in a wired local area network (LAN), so as to convey frames of data to and from the mobile station via the LAN. When one or more of the access points receive an uplink signal transmitted over the WLAN by the mobile station on the common frequency channel, the access points send messages over the LAN by interleaving the messages in one or more of the frames of the data, and arbitrate among themselves based on the messages so as to select one of the access points to respond to the uplink signal.

Claims

1. A method for mobile communication, comprising:

arranging a plurality of access points in a wireless local area network (WLAN) to communicate on a common frequency channel with a mobile station;

linking the access points together by cables in a wired local area network (LAN), so as to convey frames of data to and from the mobile station via the LAN;

receiving at one or more of the access points an uplink signal transmitted over the WLAN by the mobile station on the common frequency channel;

responsively to receiving the uplink signal, sending one or more messages over the LAN among the access points by interleaving the messages in one or more of the frames of the data;

arbitrating among the access points based on the messages so as to select one of the access points to respond to the uplink signal; and

transmitting a response from the selected one of the access points to the mobile station.

2. A method according to claim 1, wherein sending the one or more messages comprises breaking at least one of the frames of the data into a leading fragment and a tailing fragment, and appending one of the messages to the leading fragment.

3. A method according to claim 2, wherein breaking the at least one of the frames of the data comprises beginning the tailing fragment with a Start Frame Delimiter (SFD) different from the SFD normally used to begin a frame of data.

4. A method according to claim 2, wherein arbitrating among the access points comprises receiving the one or more messages at the plurality of access points by screening the frames of data so as to detect the one or more messages, and, responsively to such detection, extracting the one or more messages from the one or more of the frames of the data.

5. A method according to claim 4, wherein screening the frames of data comprises determining whether a sequence of bits in one of the frames represents a valid error detection code for a portion of the frame.

6. A method according to claim 4, wherein receiving the one or more messages comprises temporarily holding a portion of the data in one of the frames in a first-in-first-out buffer during the screening.

7. A method according to claim 1, wherein sending the one or more messages by interleaving comprises temporarily holding a portion of the data in the one or more frames in a first-in-first-out buffer during the interleaving.

8. A method according to claim 1, wherein linking the access points to convey the frames of the data comprises configuring the access points to convey the frames in accordance with a first media access control (MAC) protocol characterized by a first latency, and wherein sending the messages comprises using a second MAC protocol, having a second latency lower than the first latency, to send the messages responsively to receiving the uplink signal.

9. A method according to claim 8, wherein the first MAC protocol comprises an Ethernet protocol.

10. A method according to claim 9, wherein linking the access points to convey the frames of the data comprises passing the frames in accordance with a standard Media-Independent Interface (MII) between physical and MAC layers of the Ethernet protocol.

11. A method according to claim 1, wherein sending the one or more messages comprises sending broadcast messages from the access points receiving the uplink signal to the plurality of the access points.

12. A method according to claim 11, wherein linking the access points together comprises linking each of the access points to a hub via the LAN, and wherein sending the broadcast messages comprises sending the broadcast messages from the access points receiving the uplink signal to the hub, and from the hub to the plurality of the access points.

13. A method according to claim 1, wherein arbitrating among the access points comprises receiving and processing the messages at each of the plurality of the access points, so that each of the one or more of the access points receiving the uplink signal determines which one of the access points is to be selected to respond to the uplink signal.

14. A method according to claim 13, wherein processing the messages comprises selecting, responsively to the messages, the one of the access points that was first to receive the uplink signal.

15. A method according to claim 1, wherein the access points have respective service areas, and wherein arranging the plurality of the access points comprises arranging the access points so that the service areas substantially overlap.

16. A method according to claim 1, wherein arranging the plurality of the access points comprises arranging the access points to communicate with the mobile station substantially in accordance with IEEE Standard 802.11.

17. A method according to claim 16, wherein arbitrating among the access points comprises selecting the one of the access points to respond to the uplink signal within a time limit imposed by the IEEE Standard 802.11 for acknowledging the uplink signal.

18. A method for network communication, comprising:

linking a plurality of nodes together in a local area network (LAN);

conveying frames of data among the nodes via the LAN in accordance with a first media access control (MAC) protocol; and

sending a message among the nodes over the LAN using a second MAC protocol by interleaving the message in one of the frames of the data.

19. A method according to claim 18, wherein sending the message comprises breaking the frame of the data into a leading fragment and a tailing fragment, and appending the message to the leading fragment.

20. A method according to claim 19, wherein breaking the frame of the data comprises beginning the tailing fragment with a Start Frame Delimiter (SFD) different from the SFD normally used to begin a frame of data.

21. A method according to claim 19, wherein sending the message comprises receiving the message by screening the frames of data so as to detect the message, and, responsively to such detection, extracting the message from the frames of the data.

22. A method according to claim 21, wherein screening the frames of data comprises determining whether a sequence of bits in one of the frames represents a valid error detection code for a portion of the frame.

23. A method according to claim 21, wherein receiving the message comprises temporarily holding a portion of the data in one of the frames in a first-in-first-out buffer during the screening.

24. A method according to claim 18, wherein sending the message by interleaving comprises temporarily holding a portion of the data in the one of the frames in a first-in-first-out buffer during the interleaving.

25. A method according to claim 18, wherein the first MAC protocol is characterized by a first latency, and the second MAC protocol is characterized by a second latency lower than the first latency.

26. A method according to claim 25, wherein the first MAC protocol comprises an Ethernet protocol.

27. A method according to claim 26, wherein conveying the frames of the data comprises passing the frames in accordance with a standard Media-Independent Interface (MII) between physical and MAC layers of the Ethernet protocol.

28. A system for mobile communication, comprising:

cables arranged to form a wired local area network (LAN); and

a plurality of access points interconnected by the LAN and arranged in a wireless local area network (WLAN) to communicate on a common frequency channel with a mobile station, the access points being adapted to convey frames of data to and from the mobile station via the LAN, and, upon receiving at one or more of the access points an uplink signal transmitted over the WLAN by the mobile station on the common frequency channel, to send one or more messages over the LAN among the access points by interleaving the messages in one or more of the frames of the data, responsively to receiving the uplink signal, and to arbitrate among the access points based on the messages so as to select one of the access points to respond to the uplink signal, and to transmit a response from the selected one of the access points to the mobile station.

29. A system according to claim 28, wherein the access points are adapted to interleave the messages by breaking at least one of the frames of the data into a leading fragment and a tailing fragment, and appending one of the messages to the leading fragment.

30. A system according to claim 29, wherein the access points are adapted to begin the tailing fragment with a Start Frame Delimiter (SFD) different from the SFD normally used to begin a frame of data.

31. A system according to claim 29, wherein the access points are adapted to receive the one or more messages at the plurality of access points by screening the frames of data so as to detect the one or more messages, and, responsively to such detection, extracting the one or more messages from the one or more of the frames of the data.

32. A system according to claim 31, wherein the access points are adapted to screen the frames of data by determining whether a sequence of bits in one of the frames represents a valid error detection code for a portion of the frame.

33. A system according to claim 31, wherein each of the access points comprises a first-in-first-out buffer, which is adapted to temporarily hold a portion of the data in one of the frames during screening of the data.

34. A system according to claim 28, wherein each of the access points comprises a first-in-first-out buffer, which is adapted to temporarily hold a portion of the data in the one or more frames during the interleaving.

35. A system according to claim 28, wherein the access points are configured to convey the frames in accordance with a first media access control (MAC) protocol characterized by a first latency, and to send the messages using a second MAC protocol, having a second latency lower than the first latency.

36. A system according to claim 35, wherein the first MAC protocol comprises an Ethernet protocol.

37. A system according to claim 36, wherein the access points are configured to convey the frames of the data by passing the frames in accordance with a standard Media-Independent Interface (MII) between physical and MAC layers of the Ethernet protocol.

38. A system according to claim 28, wherein the one or more messages comprise broadcast messages, sent from the access points receiving the uplink signal to the plurality of the access points.

39. A system according to claim 38, wherein the LAN comprises a hub, linked to each of the access points, wherein the access points receiving the uplink signal are configured to send the broadcast messages to the hub, and wherein the hub is configured to send the broadcast messages to the plurality of the access points.

40. A system according to claim 28, wherein the access points are adapted to receive and process the messages so that each of the one or more of the access points receiving the uplink signal determines which one of the access points is to be selected to respond to the uplink signal.

41. A system according to claim 40, wherein the access points are adapted to select, responsively to the messages, the one of the access points that was first to receive the uplink signal.

42. A system according to claim 28, wherein the access points have respective service areas, and wherein the access points are arranged so that the service areas substantially overlap.

43. A system according to claim 28, wherein the access points are adapted to communicate with the mobile station substantially in accordance with IEEE Standard 802.11.

44. A system according to claim 43, wherein the access points are adapted to select the one of the access points to respond to the uplink signal within a time limit imposed by the IEEE Standard 802.11 for acknowledging the uplink signal.

45. A system for network communication, comprising:

cables arranged to form a wired local area network (LAN); and

a plurality of nodes, which are linked together by the LAN and are adapted to convey frames of data among the nodes via the LAN in accordance with a first media access control (MAC) protocol, and which are further adapted to send a message among the nodes over the LAN using a second MAC protocol by interleaving the message in one of the frames of the data.

46. A system according to claim 45, wherein the nodes are adapted to interleave the message by breaking the frame of the data into a leading fragment and a tailing fragment, and appending the message to the leading fragment.

47. A system according to claim 46, wherein the nodes are adapted to begin the tailing fragment with a Start Frame Delimiter (SFD) different from the SFD normally used to begin a frame of data.

48. A system according to claim 46, wherein the nodes are adapted to receive the message by screening the frames of data so as to detect the message, and, responsively to such detection, extracting the message from the frames of the data.

49. A system according to claim 48, wherein the nodes are adapted to screen the frames of data by determining whether a sequence of bits in one of the frames represents a valid error detection code for a portion of the frame.

50. A system according to claim 48, wherein each of the nodes comprises a first-in-first-out buffer, which is adapted to temporarily hold a portion of the data in the one of the frames during screening of the data.

51. A system according to claim 45, wherein each of the nodes comprises a first-in-first-out buffer, which is adapted to temporarily hold a portion of the data in the one of the frames during the interleaving.

52. A system according to claim 45, wherein the first MAC protocol is characterized by a first latency, and the second MAC protocol is characterized by a second latency lower than the first latency.

53. A system according to claim 52, wherein the first MAC protocol comprises an Ethernet protocol.

54. A system according to claim 53, wherein the nodes are adapted to convey the frames of the data by passing the frames in accordance with a standard Media-Independent Interface (MII) between physical and MAC layers of the Ethernet protocol.

55. Access point apparatus for deployment in a wireless local area network (WLAN) as one of a plurality of access points for mobile communication, the apparatus comprising:

a radio transceiver, which is configured to communicate on a predetermined frequency channel with a mobile station;

a physical layer interface, for connecting the access point to a wired local area network (LAN) interconnecting the access points; and

processing circuitry, which is adapted to convey frames of data to and from the mobile station via the physical layer interface over the LAN, and, when the transceiver receives an uplink signal transmitted over the WLAN by the mobile station on the predetermined frequency channel, to send and receive messages via the physical layer interface over the LAN to and from the plurality of access points by interleaving the messages in one or more of the frames of the data, and to perform an arbitration among the access points based on the messages so as to select one of the access points to respond to the uplink signal, and to control the transceiver so that the transceiver returns a response to the mobile station subject to the arbitration.

56. Apparatus according to claim 55, wherein the processing circuitry is adapted to interleave the messages by breaking at least one of the frames of the data into a leading fragment and a tailing fragment, and appending one of the messages to the leading fragment.

57. Apparatus according to claim 56, wherein the processing circuitry is adapted to begin the tailing fragment with a Start Frame Delimiter (SFD) different from the SFD normally used to begin a frame of data.

58. Apparatus according to claim 56, wherein the processing circuitry is adapted to receive the one or more messages at the plurality of access points by screening the frames of data so as to detect the one or more messages, and, responsively to such detection, extracting the one or more messages from the one or more of the frames of the data.

59. Apparatus according to claim 58, wherein the processing circuitry is adapted to screen the frames of data by determining whether a sequence of bits in one of the frames represents a valid error detection code for a portion of the frame.

60. Apparatus according to claim 58, wherein the processing circuitry comprises a first-in-first-out buffer, which is adapted to temporarily hold a portion of the data in the one or more frames during screening of the data.

61. Apparatus according to claim 55, wherein the processing circuitry comprises a first-in-first-out buffer, which is adapted to temporarily hold a portion of the data in the one or more frames during the interleaving.

62. Apparatus according to claim 55, wherein the processing circuitry comprises:

a first MAC processor, adapted to convey the frames in accordance with a first media access control (MAC) protocol characterized by a first latency; and

a second MAC processor, adapted to send the messages using a second MAC protocol, having a second latency lower than the first latency.

63. Apparatus according to claim 62, wherein the first MAC protocol comprises an Ethernet protocol.

64. Apparatus according to claim 63, wherein the processing circuitry is adapted to convey the frames of the data by passing the frames in accordance with a standard Media-Independent Interface (MII) between physical and MAC layers of the Ethernet protocol.

65. Apparatus according to claim 55, wherein the one or more messages comprise broadcast messages, sent from the access points receiving the uplink signal to the plurality of the access points.

66. Apparatus according to claim 65, wherein the LAN comprises a hub, linked to the physical layer interface of each of the access points, wherein the processing circuitry is adapted to send the broadcast messages to the hub when the transceiver receives the uplink signal, and wherein the hub is configured to send the broadcast messages to the physical layer interface of each of the plurality of the access points.

67. Apparatus according to claim 55, wherein the processing circuitry is adapted to receive and process the messages so that each of the one or more of the access points receiving the uplink signal determines which one of the access points is to be selected to respond to the uplink signal.

68. Apparatus according to claim 67, wherein the processing circuitry is adapted to select, responsively to the messages, the one of the access points that was first to receive the uplink signal.

69. Apparatus according to claim 55, wherein the access points have respective service areas, and wherein the access points are arranged so that the service areas substantially overlap.

70. Apparatus according to claim 55, wherein the transceiver is adapted to communicate with the mobile station substantially in accordance with IEEE Standard 802.11.

71. Apparatus according to claim 70, wherein the processing circuitry is adapted to select the one of the access points to respond to the uplink signal within a time limit imposed by the IEEE Standard 802.11 for acknowledging the uplink signal.

72. Node apparatus for deployment as one of a plurality of nodes in a local area network (LAN), the apparatus comprising:

a physical layer interface, for connecting the node to the LAN; and

processing circuitry, which is adapted to convey frames of data among the nodes via the physical layer interface over the LAN in accordance with a first media access control (MAC) protocol, and which is further adapted to send a message among the nodes over the LAN using a second MAC protocol by interleaving the message in one of the frames of the data.

73. Apparatus according to claim 72, wherein the processing circuitry is adapted to interleave the message by breaking the frame of the data into a leading fragment and a tailing fragment, and appending the message to the leading fragment.

74. Apparatus according to claim 73, wherein the processing circuitry is adapted to begin the tailing fragment with a Start Frame Delimiter (SFD) different from the SFD normally used to begin a frame of data.

75. Apparatus according to claim 73, wherein the processing circuitry is adapted to receive the message by screening the frames of data so as to detect the message, and, responsively to such detection, to extract the message from the frames of the data.

76. Apparatus according to claim 75, wherein the processing circuitry is adapted to screen the frames of data by determining whether a sequence of bits in one of the frames represents a valid error detection code for a portion of the frame.

77. Apparatus according to claim 75, wherein the processing circuitry comprises a first-in-first-out buffer, which is adapted to temporarily hold a portion of the data in the one of the frames during screening of the data.

78. Apparatus according to claim 72, wherein the processing circuitry comprises a first-in-first-out buffer, which is adapted to temporarily hold a portion of the data in the one of the frames during the interleaving.

79. Apparatus according to claim 72, wherein the first MAC protocol is characterized by a first latency, and the second MAC protocol is characterized by a second latency lower than the first latency.

80. Apparatus according to claim 79, wherein the first MAC protocol comprises an Ethernet protocol.

81. Apparatus according to claim 80, wherein the processing circuitry is adapted to convey the frames of the data by passing the frames in accordance with a standard Media-Independent Interface (MII) between physical and MAC layers of the Ethernet protocol.