System and method for hybrid coordination in a wireless LAN

• US 20030081583A1
• Filed: 10/16/2002
• Published: 05/01/2003
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kowalski, John
• Granted Patent: US 7,330,472 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04W 4/00 Services specially adapted for wireless communication networks; Facilities therefor
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A system and method are provided for maintaining a hybrid coordinator (HC) in a wireless communications local area network (LAN). The method comprises: a station (STA) seeking a guaranteed quality of service (QoS); establishing a basic service set (BSS) through association with an access point (AP); the AP selecting a HC from STAs in the BSS; the AP broadcasting the HC information to STAs in the BSS; and, the STA initiating a transmission specification (TSPEC) with the HC. In one aspect, selecting an HC from STAs in the first BSS includes integrating the HC function into the AP. Then, a STA seeking a guaranteed quality of service (QoS): receives a broadcast message including a list of potential APs; and, communicates with an AP from the broadcast list. If the STA is unable to communicate with an established AP, then it instantiates a BSS with itself as the AP.

Claims

1. A method for maintaining a hybrid coordinator (HC) in a wireless communications local area network (LAN), the method comprising:

a first station (STA) seeking a guaranteed quality of service (QoS);

establishing a first basic service set (BSS) through association with a first access point (AP);

the first AP selecting a first HC from STAs in the first BSS;

the first AP broadcasting the first HC information to STAs in the first BSS; and

,

the first STA initiating a transmission specification (TSPEC) with the first HC.

2. The method of claim 1 wherein broadcasting the first HC information to STAs in the first BSS includes the first AP broadcasting first HC information selected from the group including the media access control (MAC) address and capabilities.

3. The method of claim 2 wherein a first STA seeking a guaranteed quality of service (QoS) includes the first STA sending a probe message to the first AP requesting the identity of the first HC.

4. The method of claim 3 wherein the first STA sending a probe message to the first AP requesting the identity of the first HC includes the first STA communicating its eligibility for performing the HC task.

5. The method of claim 4 wherein selecting a first HC from STAs in the first BSS includes:

the first AP sending a response to the first STA with the identity of the first HC; and

,

if there is no first HC, selecting a first HC.

6. The method of claim 5 further comprising:

the first HC maintaining a QoS table including information selected from the group including the STA streams being managed, the STAs receiving QoS, the QoS parameters, and the transmit queue state.

7. The method of claim 6 further comprising:

the first AP losing communication with the first HC;

the first AP accepting the QoS table from the first HC;

the first AP selecting a second HC to replace the first HC; and

,

the first AP sending the QoS table to the second HC.

8. The method of claim 7 further comprising:

following the selection of the second HC, the first STA initiating a new TSPEC with the second HC.

9. The method of claim 8 wherein losing communication with the first HC includes the first AP making a determination based on AP communication considerations selected from the group including received power level, channel quality, and frame error rate, and the ability of the first HC to communicate with STAs requesting a QoS in the first BSS.

10. The method of claim 1 wherein selecting a first HC from STAs in the first BSS includes the first AP selecting as follows:

in response to maintaining a candidate HC list; and

,

in response to a request from an HC candidate STA.

11. The method of claim 6 further comprising:

the first HC sending a message to the first AP announcing the disestablishment of its HC function;

the first AP broadcasting the first HC disestablishment announcement to STAs in the BSS; and

,

the first AP selecting a second HC to replace the first HC.

12. The method of claim 6 further comprising:

the first HC sending a message to the first AP announcing its separation from the first BSS;

the first AP broadcasting the first HP separation announcement to STAs in the first BSS; and

,

the first AP selecting a second HC to replace the first HC.

13. The method of claim 3 wherein the first AP selecting a first HC from STAs in the first BSS includes integrating the HC function into the first AP.

14. The method of claim 13 wherein a first STA seeking a guaranteed quality of service (QoS) includes:

the first STA receiving a broadcast message including a list of potential APs; and

,

communicating with an AP from the list.

15. The method of claim 13 wherein establishing a first BSS with a first AP includes:

the first STA being unable to communicate with an established AP; and

,

the first STA issuing a MAC layer Management Entity START (MLME-STARt) primitive, instantiating a first BSS with itself as the first AP.

16. The method of claim 13 further comprising:

the first AP determining that communication with the first STA is no longer feasible;

the first AP sending a dissociation message to all STAs in the first BSS receiving a QoS;

the first STA communicating to become associated with a second AP; and

,

the first STA initiating a new TSPEC with the second AP.

17. The method of claim 16 further comprising:

the first AP communicating to become associated as a STA with a second AP.

18. A method for establishing a hybrid coordinator (HC) in a wireless communications local area network (LAN), the method comprising:

a station (STA) attempting to associate with an access point (AP) in a basic service set (BSS);

failing the association attempt;

the STA establishing itself as an AP; and

,

the AP functions as an HC to perform guaranteed quality of service (QoS) functions.

19. The method of claim 18 wherein the STA establishing itself as an AP includes the STA restarting its media access control (MAC) process as an AP.

20. The method of claim 19 wherein a STA attempting to associate with an AP in a BSS includes:

maintaining a list of AP service set identifiers (SSIDs); and

,

scanning to acquire an AP from the list.

21. The method of claim 20 wherein the STA establishing itself as an AP includes the STA creating an AP SSID.

22. The method of claim 20 wherein the STA establishing itself as an AP includes:

maintaining an SSID in memory to uniquely identify a BSS; and

,

using the SSID to create a BSS.

23. A system for maintaining a hybrid coordinator (HC) in a wireless communications local area network (LAN), the system comprising:

a first HC having a wireless communications port for managing guaranteed quality of service (QoS) functions;

a first access point (AP) for selecting the first HC, the first AP including a wireless communications port to broadcast HC information;

a first basic service set (BSS) including the first AP and the first HC; and

,

at least a first station (STA) in the first BSS having a wireless communications port for requesting a guaranteed quality of service (QoS) from the first AP and initiating a transmission specification (TSPEC) with the first HC.

24. The system of claim 23 wherein the first AP broadcasts HC information selected from the group including the media access control (MAC) address and capabilities.

25. The system of claim 24 wherein the first STA sends a probe message to the first AP requesting the identity of the first HC.

26. The system of claim 25 wherein the first STA sends an indication to the first AP as to whether the first STA is eligible to perform the HC task.

27. The system of claim 26 wherein the first HC is a STA in the first BSS;

and,

wherein the first AP sends a message to the first STA with the identity of the first HC, and if there is no first HC, selects a STA in the first BSS as the first HC.

28. The system of claim 27 wherein the first HC maintains a QoS table including information selected from the group including the STA streams being managed, the STAs receiving QoS, the QoS parameters, and the transmit queue state.

29. The system of claim 28 wherein the first AP requests the QoS table from the first HC in response to losing communication with the first HC, the first AP selecting a second HC and sending the QoS table to the second HC.

30. The system of claim 29 wherein the first STA, following the selection of the second HC, initiates a new TSPEC with the second HC.

31. The system of claim 30 wherein the first AP determines whether it is losing communication with the HC based on considerations selected from the group including AP communication received power levels, channel quality, and frame error rate, and the ability of the first HC to communicate with STAs in the first BSS requesting a QoS.

32. The system of claim 23 wherein the first AP includes a candidate HC list and selects an HC in response to the candidate list.

33. The system of claim 23 wherein the first STA makes a request to the first AP to become an HC candidate;

and,

wherein the first AP selects an HC in response to HC candidate requests.

34. The system of claim 28 wherein the first HC sends a message to the first AP announcing the disestablishment of its HC function;

and,

wherein the first AP broadcasts the first HC disestablishment announcement to STAs in the first BSS receiving a QoS, and selects a second HC to replace the first HC.

35. The system of claim 28 wherein the first HC sends a message to the first AP announcing its separation from the first BSS;

and,

wherein the first AP broadcasts the first HP separation announcement to STAs in the first BSS receiving a QoS and selects a second HC to replace the first HC.

36. The system of claim 25 wherein the first HC is the first AP.

37. The system of claim 36 wherein the first STA receives a broadcast message including a list of potential APs and communicates with an AP from the broadcast list.

38. The system of claim 36 wherein the first STA includes a list of potential APs and communicates with an AP from the broadcast list.

39. The system of claim 36 wherein the first STA is unable to communicate with an established AP and issues a MAC layer Management Entity START (MLME-STARt) primitive, instantiating the first BSS with itself as the first AP.

40. The system of claim 36 wherein the first AP determines that communication with the first STA is no longer feasible and sends a dissociation message to all STAs in the first BSS receiving a QoS;

and,

the system further comprising;

at least a second BSS with a second AP; and

,

wherein the first STA communicates to become associated with the second AP and initiates a new TSPEC with the second AP.

41. The system of claim 40 wherein the first AP communicating to become associated as a STA with a second AP.