Method and apparatus for selecting an access point in a wireless network

• US 6,522,881 B1
• Filed: 03/08/2000
• Issued: 02/18/2003
• Est. Priority Date: 03/08/2000
• Status: Expired due to Term

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Honcharenko, Walter, Feder, Peretz M., Ner, Haim S.
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Tran, Congvan
• Application Number:
  US09/520,715
• Time in Patent Office: 1,077 Days
• Field of Search: 455/434, 455/437, 455/438, 455/445, 455/447, 455/448, 455/454, 455/464, 455/414, 455/428, 455/9, 455/507, 455/511, 455/513, 455/671
• US Class Current: 455/437
• CPC Class Codes: H04W 16/06 Hybrid resource partitioning, e.g. channel borrowing
• CPC Class Codes: H04W 48/20 Selecting an access point

Abstract

A method and apparatus for use in a wireless communications network searches for the best serving access point of a base station as a function of communication link quality and load levels, thereby allowing a subscriber terminal to react to changes in RF conditions and load levels. In one implementation, a wireless modem in a fixed wireless access network initiates an access point searching algorithm in response to a triggering condition, such as initially powering-up the subscriber terminal or degradation of communication link quality or load levels. After detecting beacons for a plurality of neighboring access points, the wireless modem selects the best access point as a function of communication link quality and relative load levels to maintain adequate service quality and to react to changes in load levels. After an initial selection, the wireless modem may continually monitor quality/load conditions to determine whether to select a new access point.

Claims

1. A method of selecting an access point in a wireless communications network, comprising:

detecting a beacon of an access point on a selected radio frequency search channel;

obtaining a neighbor list from the detected beacon, the neighbor list indicating radio frequency channels associated with a plurality of neighboring access points;

detecting a beacon of each of the neighboring access points on the radio frequency channels indicated in the neighbor list; and

selecting a single access point as a function of the relative load levels associated with the access points.

2. The method of claim 1, wherein said step of selecting a single access point considers communication link quality associated with each of the access points.

3. The method of claim 2, wherein communication link quality is forward link quality.

4. The method of claim 2, wherein communication link quality is reverse link quality.

5. The method of claim 1, wherein detecting beacons is initiated when a load level associated with a currently serving access point exceeds a threshold.

6. The method of claim 1, wherein detecting beacons is initiated when communication link quality for a currently serving access point degrades below a threshold.

7. The method of claim 1, wherein detecting a beacon of an access point includes:

setting an initial radio frequency search channel;

determining whether a beacon can be detected on the initial radio frequency search channel; and

setting an updated frequency search channel, within an acceptable range of search channels,

wherein said step of setting an updated frequency search channel is repeated until a beacon can be detected.

8. The method of claim 1, wherein said wireless communications network is a fixed wireless access network.

9. The method of claim 8, wherein said steps of detecting beacons and selecting a single access point are performed by a wireless modem of the fixed wireless access network.

10. The method of claim 9, wherein said step of detecting a beacon of an access point is initiated when the wireless modem is powered-up.

11. The method of claim 2, wherein communication link quality is determined by receive signal strength measurements and/or signal quality measurements.

12. An apparatus for selecting an access point in a wireless communications network comprising:

detecting means for

detecting a beacon of an access point on a selected radio frequency search channel,

obtaining a neighbor list from the detected beacon, the neighbor list indicating radio frequency channels associated with a plurality of neighboring access points, and

detecting a beacon of each of the neighboring access points on the radio frequency channels indicated in the neighbor list; and

selecting means for selecting a single access point as a function of the relative load levels associated with the access points.

13. The apparatus of claim 12, wherein said selecting means considers communication link quality associated with each of the access points when selecting the single access point.

14. The apparatus of claim 13, wherein communication link quality is forward link quality.

15. The apparatus of claim 13, wherein communication link quality is reverse link quality.

16. The apparatus of claim 12, wherein said detecting means initiates detecting beacons when a load level associated with a currently serving access point exceeds a threshold.

17. The apparatus of claim 12, wherein said detecting means initiates detecting beacons when communication link quality for a currently serving access point degrades below a threshold.

18. The apparatus of claim 21, wherein said detecting means detects a beacon by:

setting an initial radio frequency search channel;

determining whether a beacon can be detected on the initial radio frequency search channel; and

setting an updated frequency search channel, within an acceptable range of search channels,

wherein setting an updated frequency search channel is repeated until a beacon can be detected.

19. The apparatus of claim 12, wherein said wireless communications network is a fixed wireless access network.

20. The apparatus of claim 19, wherein said apparatus is a wireless modem of the fixed wireless access network.

21. The apparatus of claim 20, wherein said detecting means initiates detecting beacons when said wireless modem is powered-up.

22. The apparatus of claim 13, wherein communication link quality is determined by receive signal strength measurements and/or signal quality measurements.