Wireless LAN control over a wired network

• US 20040156399A1
• Filed: 01/26/2004
• Published: 08/12/2004
• Est. Priority Date: 08/07/2002
• Status: Active Grant

• Current Assignee: Allied Telesis Israel Ltd.
• Original Assignee: Extricom Limited (Allied Telesis Holdings KK)
• Inventors: Eran, Shpak
• Granted Patent: US 7,697,549 B2
• Time in Patent Office: Days
• US Class Current: 370/395.5
• CPC Class Codes: H04J 13/0048 Walsh
• 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 88/08 Access point devices
• CPC Class Codes: H04W 92/045 between access point and backbone network device
• CPC Class Codes: H04W 92/20 between access points
• CPC Class Codes: Y10S 370/913 Wireless or radio

Abstract

Apparatus for mobile communication includes a switch and a plurality of access points, which are arranged in a wireless local area network (WLAN) to communicate over the air on a common frequency channel with a mobile station using a common basic service set identification (BSSID) for all the access points. The access points are coupled by a LAN to the switch so that 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, the one or more of the access points convey messages responsively to the uplink signal over the LAN to the switch. A manager node is coupled to the switch so as to receive the messages and is adapted to process the messages so as to select one of the access points to respond to the uplink signal.

Claims

1. Apparatus for mobile communication, comprising:

a switch, having a plurality of ports for connection to a wired local area network (LAN);

a plurality of access points, which are arranged in a wireless local area network (WLAN) to communicate over the air on a common frequency channel with a mobile station using a common basic service set identification (BSSID) for all the access points, and which are coupled by the LAN to the switch so that 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, the one or more of the access points convey messages responsively to the uplink signal over the LAN to the switch; and

a manager node, which is coupled to the switch so as to receive the messages and is adapted to process the messages so as to select one of the access points to respond to the uplink signal, and to send an instruction via the switch to the selected one of the access points to transmit a response to the mobile station.

2. The apparatus according to claim 1, wherein the access points have respective service areas, and are arranged so that the service areas substantially overlap.

3. The apparatus according to claim 1, wherein the access points are configured to communicate with the mobile station substantially in accordance with IEEE Standard 802.11.

4. The apparatus according to claim 1, wherein the LAN is an Ethernet LAN.

5. The apparatus according to claim 1, wherein the LAN is characterized by a data transmission rate of at least 1 Gbps.

6. The apparatus according to claim 1, wherein the LAN is characterized by a data transmission rate that is substantially less than 1 Gbps.

7. The apparatus according to claim 1, wherein the manager node has an address on the LAN, and wherein the access points are adapted to convey the messages over the LAN in the form of data frames directed to the address of the manager node.

8. The apparatus according to claim 7, wherein the access points are configured to communicate over the LAN exclusively with the manager node.

9. The apparatus according to claim 7, wherein the access points are adapted to receive an uplink data packet sent by the mobile station using the uplink signal, and to fragment the uplink data packet among a succession of the data frames for conveyance over the LAN via the switch to the manager node.

10. The apparatus according to claim 9, wherein the access points are operative to fragment the uplink data packet so that the data frames have a length that is no more than 10% of a maximum frame length permitted on the LAN.

11. The apparatus according to claim 9, wherein the access points are operative to fragment the uplink data packet so that the data frames have a length that is equal to a minimum frame length permitted on the LAN.

12. The apparatus according to claim 9, wherein the uplink data packet comprises a destination address, and wherein the manager node is adapted to reassemble the uplink data packet from the succession of the data frames, and to convey the reassembled packet via the switch over the LAN to the destination address.

13. The apparatus according to claim 12, wherein the manager node is connected to first and second ports among the plurality of the ports of the switch, and is configured to receive the data frames from the access points through the first port and to convey the reassembled packet to the LAN via the second port.

14. The apparatus according to claim 13, wherein the manager node is further configured to receive a downlink data packet from the LAN via the second port, and to fragment the downlink data packet into a further succession of the data frames and to convey the further succession of the data frames via the first port to the selected one of the access points, which is operative to reassemble the downlink data packet for transmission over the WLAN to the mobile station.

15. The apparatus according to claim 9, wherein the address of the manager node on the LAN comprises a Layer 3 address, and wherein each of the succession of the data frames among which the uplink data packet is fragmented comprises a Layer 3 encapsulating packet, having a destination address corresponding to the Layer 3 address of the manager node.

16. The apparatus according to claim 1, wherein the messages conveyed by the access points responsively to the uplink signal comprise an indication of a strength of the uplink signal received respectively by each of the one or more of the access points, and wherein the manager node is adapted to select, responsively to the indication and prior to receiving the messages from all of the one or more of the access points, the one of the access points to respond to the uplink signal.

17. The apparatus according to claim 16, wherein the access points are adapted to set, responsively to the strength of the uplink signal, a priority indicator in the messages to be conveyed over the LAN so as to cause the switch to deliver a first message indicating a strong uplink signal before delivering a second message indicating a weak uplink signal.

18. The apparatus according to claim 16, wherein the access points are adapted, responsively to the strength of the uplink signal, to delay transmission of some of the messages over the LAN, so that a first message indicating a strong uplink signal is transmitted with a smaller delay than a second message indicating a weak uplink signal.

19. Apparatus for mobile communication, comprising:

a switch, having a plurality of ports for connection to a wired local area network (LAN);

a plurality of access points, which are arranged in a wireless local area network (WLAN) to communicate over the air with a mobile station, and which are coupled by the LAN to the switch so that upon receiving at one or more of the access points an uplink message transmitted over the WLAN by the mobile station, the one or more of the access points convey the uplink message over the LAN to the switch; and

a manager node, which is connected to first and second ports among the plurality of the ports of the switch, and is configured to receive the uplink message from the access points through the first port and to convey the uplink message via the second port over the LAN to a destination address of the message.

20. The apparatus according to claim 19, wherein the access points are configured to communicate over the LAN exclusively with the manager node via the first port in response to uplink messages received from the mobile station.

21. The apparatus according to claim 19, wherein the access points are configured to communicate with the mobile station substantially in accordance with IEEE Standard 802.11.

22. The apparatus according to claim 19, wherein the manager node has first and second addresses on the LAN, which are respectively associated with the first and second ports, and wherein the access points are adapted to convey the uplink message over the LAN in the form of data frames directed to the first address.

23. The apparatus according to claim 22, wherein the uplink message comprises a data packet, and wherein the access points are adapted to fragment the uplink data packet among a succession of the data frames for conveyance over the LAN to the first address, and wherein the manager node is adapted to reassemble the data packet from the succession of the data frames, and to convey the reassembled data packet via the second port over the LAN to the destination address, using the second address as a source address.

24. The apparatus according to claim 23, wherein the access points are operative to fragment the data packet so that the data frames have a length that is no more than 10% of a maximum frame length permitted on the LAN.

25. The apparatus according to claim 23, wherein the access points are operative to fragment the data packet so that the data frames have a length that is equal to a minimum frame length permitted on the LAN.

26. The apparatus according to claim 23, wherein the address of the manager node on the LAN comprises a Layer 3 address, and wherein each of the succession of the data frames among which the uplink data packet is fragmented comprises a Layer 3 encapsulating packet, which is addressed to the Layer 3 address of the manager node.

27. The apparatus according to claim 19, wherein the manager node is further configured to receive a downlink message from the LAN via the second port, and to convey the downlink message via the first port to one of the access points, which is operative to transmit the downlink message over the WLAN to the mobile station.

28. A method for mobile communication, comprising:

arranging a plurality of access points in a wireless local area network (WLAN) to communicate over the air with a mobile station using a common basic service set identification (BSSID) for all the access points;

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

conveying messages responsively to the uplink signal from the one or more of the access points over a wired local area network (LAN) linking the access points to a manager node;

processing the messages at the manager node so as to select one of the access points to respond to the uplink signal, and conveying a response instruction from the manager node to the selected one of the access points; and

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

29. The method according to claim 28, 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.

30. The method according to claim 28, 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.

31. The method according to claim 28, wherein the LAN is an Ethernet LAN.

32. The method according to claim 31, wherein conveying the messages comprises sending the messages over the Ethernet LAN at a data transmission rate of at least 1 Gbps.

33. The method according to claim 31, wherein conveying the messages comprises sending the messages over the Ethernet LAN at a data transmission rate that is substantially less than 1 Gbps.

34. The method according to claim 28, wherein the manager node has an address on the LAN, and wherein conveying the messages comprises transmitting the messages over the LAN in the form of data frames directed to the address of the manager node.

35. The method according to claim 34, wherein the access points are configured to communicate over the LAN exclusively with the manager node.

36. The method according to claim 34, wherein receiving the uplink signal comprises receiving an uplink data packet sent by the mobile station, and wherein transmitting the messages comprises fragmenting the uplink data packet among a succession of the data frames for conveyance over the LAN via the switch to the manager node.

37. The method according to claim 36, wherein fragmenting the uplink data packet comprises generating the data frames with a length that is no more than 10% of a maximum frame length permitted on the LAN.

38. The method according to claim 36, wherein fragmenting the uplink data packet comprises generating the data frames with a length that is equal to a minimum frame length permitted on the LAN.

39. The method according to claim 36, wherein the uplink data packet comprises a destination address, and comprising reassembling the uplink data packet at the manager node from the succession of the data frames, and conveying the reassembled packet over the LAN to the destination address.

40. The method according to claim 39, wherein the LAN comprises a switch, and the manager node is connected to first and second ports of the switch, and wherein transmitting the messages comprises transmitting the data frames from the access points through the first port to the manager node, and wherein conveying the reassembled packet comprises transmitting the reassembled packet to the LAN via the second port.

41. The method according to claim 40, and comprising:

receiving at the manager node a downlink data packet from the LAN via the second port;

fragmenting the downlink data packet into a further succession of the data frames;

conveying the further succession of the data frames via the first port to the selected one of the access points; and

reassembling the downlink data packet at the selected one of the access points for transmission over the WLAN to the mobile station.

42. The method according to claim 36, wherein the address of the manager node on the LAN comprises a Layer 3 address, and wherein each of the succession of the data frames among which the uplink data packet is fragmented comprises a Layer 3 encapsulating packet, having a destination address corresponding to the Layer 3 address of the manager node.

43. The method according to claim 28, wherein conveying the messages comprises conveying an indication of a strength of the uplink signal received respectively by each of the one or more of the access points, and wherein processing the messages comprises selecting at the manager node, responsively to the indication and prior to receiving the messages from all of the one or more of the access points, the one of the access points to respond to the uplink signal.

44. The method according to claim 43, wherein conveying the indication comprises setting, responsively to the strength of the uplink signal, a priority indicator in the messages to be conveyed over the LAN so as to cause the switch to deliver a first message indicating a strong uplink signal before delivering a second message indicating a weak uplink signal.

45. The method according to claim 43, wherein conveying the indication comprises delaying, responsively to the strength of the uplink signal, transmission of some of the messages, so that a first message indicating a strong uplink signal is transmitted with a smaller delay than a second message indicating a weak uplink signal.

46. A method for mobile communication, comprising:

coupling a manager node to first and second ports among a plurality of ports of a switch in a wired local area network (LAN);

arranging a plurality of access points in a wireless local area network (WLAN) to communicate over the air with a mobile station;

receiving at one or more of the access points an uplink message transmitted over the WLAN by the mobile station, the uplink message containing a destination address;

passing the uplink message from the one or more of the access points over the LAN to the manager node via the first port of the switch; and

conveying the uplink message from the manager node via the second port over the LAN to the destination address.

47. The method according to claim 46, wherein arranging the plurality of the access points comprises configuring the access points to communicate over the LAN exclusively with the manager node via the first port in response to uplink messages received from the mobile station.

48. The method according to claim 46, 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.

49. The method according to claim 46, wherein coupling the manager node comprises assigning to the manager node first and second addresses on the LAN, which are respectively associated with the first and second ports, and wherein passing the uplink message comprises sending the uplink message over the LAN in the form of one or more data frames directed to the first address.

50. The method according to claim 49, wherein the uplink message comprises an uplink data packet, and wherein passing the uplink message comprises fragmenting the upstream data packet among a succession of the data frames for conveyance over the LAN to the MAC address, and wherein conveying the uplink message comprises reassembling the data packet from the succession of the data frames, and conveying the reassembled packet via the second port over the LAN to the destination address, using the second address as a source address.

51. The method according to claim 50, wherein fragmenting the uplink data packet comprises generating the data frames with a length that is no more than 10% of a maximum frame length permitted on the LAN.

52. The method according to claim 50, wherein fragmenting the uplink data packet comprises generating the data frames with a length that is equal to a minimum frame length permitted on the LAN.

53. The method according to claim 50, wherein the address of the manager node on the LAN comprises a Layer 3 address, and wherein each of the succession of the data frames among which the uplink data packet is fragmented comprises a Layer 3 encapsulating packet, which is addressed to the Layer 3 address of the manager node.

54. The method according to claim 46, and comprising:

receiving at the manager node a downlink message from the LAN via the second port;

conveying the downlink message via the first port from the manager node to one of the access points; and

transmitting the downlink message over the WLAN from the one of the access points to the mobile station.