| US 7,499,964 B2 | ||
| Wireless LAN with channel swapping between DFS access points | ||
| Patrick Busch, Veldhoven (Netherlands); and Richa Malhotra, Enschede (Netherlands) | ||
| Assigned to Agere Systems Inc., Allentown, Pa. (US) | ||
| Filed on May 08, 2002, as Appl. No. 10/141,189. | ||
| Claims priority of application No. 01304146 (EP), filed on May 08, 2001. | ||
| Prior Publication US 2002/0176437 A1, Nov. 28, 2002 | ||
| Int. Cl. G06F 15/16 (2006.01) | ||
| U.S. Cl. 709—200 [370/328; 455/421; 455/422.1; 455/432.1] | 24 Claims |
| 1. A first access point for a wireless LAN communication network, wherein the first access point is adapted to:
(a) send probe requests and probe responses to other access points,
(b) receive probe requests and probe responses from other access points
(c) calculate an interference parameter for each of a plurality of its possible channels
(d) calculate a channel sharing parameter for each of said plurality of channels
(e) calculate a regular channel quality parameter (regCSIQ) for each of said plurality of channels, indicative of the amount
of interference and channel sharing on each of said plurality of channels, using said interference and channel sharing parameters
(f) dynamically select a new channel from said plurality of possible channels using said regular channel quality parameters
(regCSIQ),
wherein said first access point is arranged to select said new channel by mutually swapping channels with a second access
point using a swapping mechanism in which:
the new channel for the first access point is the previous channel for the second access point;
the new channel for the second access point is the previous channel for the first access point; and
said first access point is a swap requesting access point (AP1), operating on a first channel (C1), that calculates and stores a swap specific channel quality parameter (ssCSIQ) for every responding access point (AP2) operating on a second channel (C2), said swap specific channel quality parameter (ssCSIQ) being calculated under the assumption that every responding access
point (AP2) and said swap requesting access point (AP1) have already swapped channels, which swap specific channel quality parameter is used in said swapping mechanism, wherein
said first access point is adapted to:
(a) calculate a benefit-in-performance parameter (SwapBinP) having a value equal to a difference between a lowest of all regular
channel quality parameters and a lowest of all swap specific channel quality parameters
(b) send a swap request containing said benefit-in-performance parameter (SwapBinP) to the second access point that corresponds
to said lowest of all swap specific channel quality parameters of all said responding access points (AP2);
(c) wait for a swap response from said second access point (AP2);
(d) switch to the new channel based on said swap response.
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