	US 7,468,960 B2
	Network system comprising access points
Geert Arnout Awater, Utrecht (Netherlands); Wilhelmus Diepstraten, Noord-Brabant (Netherlands); and Adriaan Kamerman, Utrecht (Netherlands)
Assigned to Agere Systems Inc., Allentown, Pa. (US)
Filed on May 08, 2002, as Appl. No. 10/140,689.
Claims priority of application No. 01304148 (EP), filed on May 08, 2001.
Prior Publication US 2002/0181418 A1, Dec. 05, 2002
Int. Cl. H04Q 7/00 (2006.01)

U.S. Cl. 370—329 [370/252; 455/450]

13 Claims

1. A method for selecting a channel frequency for wireless communication between a first access point (AP) and a non-AP station in a communications network operating according to a medium access scheme, the method comprising:

(a) transmitting, from the first AP, a plurality of probe signals at a plurality of different channel frequencies;

(b) receiving, at the first AP, a plurality of response signals, each response signal transmitted by a different AP, in response to receipt of one of the probe signals, at a channel frequency corresponding to the channel frequency of the received probe signal;

(d) characterizing reception level of each channel frequency based on the reception level of each corresponding received response signal;

(e) determining load level of each channel frequency based on the received response signals, wherein the load level is different from the reception level;

(f) determining noise level of each channel frequency based on the received response signals, wherein the noise level is different from the reception level and the load level;

(g) generating, for each channel frequency, a cost function value using a closed-form expression that is a function of a reception level parameter, a load level parameter, and a noise level parameter, wherein:

the reception level parameter is based on the characterized reception level of step (d);

the load level parameter is based on the determined load level of step (e); and

the noise level parameter is based on the determined noise level of step (f); and

(h) selecting the channel frequency for the wireless communication between the first AP and the non-AP station based on the cost function values for the plurality of different channel frequencies.