Relieving congestion in wireless local area networks

摘要

A wireless local area network, WLAN, comprising: access points arranged to maintain wireless links with terminals each arranged to initiate a wireless link with an access point, and to associate with an access point during a service session. A central association server is connected to each of the access points, and is arranged to gather information from a plurality of the terminals via the wireless links between terminals and access points, determine, based on the gathered information, with which access point a terminal which has initiated a wireless link should associate during its service session, and notify the terminal, via the access point with which the terminal initiated the wireless link, of the access point so determined.

主权项

1. A wireless local area network, WLAN, comprising:
access points arranged to maintain wireless links with terminals; terminals each arranged to initiate a wireless link with an access point and become connected, and thereafter to transition to an active mode in which the terminal associates with an access point during a service session; and a central association server connected to each of the access points, and arranged to: gather information from a plurality of the connected terminals via the wireless links between terminals and access points; determine, based on the gathered information, with which access point a terminal which has initiated a wireless link and become connected should associate during its service session; and notify the terminal, via the access point with which the terminal initiated the wireless link, of the access point so determined; wherein the terminals are arranged, after initiating a wireless link with an access point and becoming connected but before transitioning to the active mode, to send a session request to that access point, and the central association server is arranged to detect the session request and to perform the determining in response to detecting the session request; and the information gathered from a terminal by the central association server includes at least an indication of a channel condition between the terminal and each of a plurality of access points and an indication of congestion on a wireless link between the terminal and an access point which maintains the wireless link with the terminal; wherein the central association server is arranged to derive a transmission rate from the indication of channel condition received from a terminal with respect to an access point, and to combine the transmission rate with indications of congestion with respect to the said access point received from other said terminals, to form an association indicator for the said terminal with respect to the said access point, the association indicator having a value representing an expected data rate of a wireless link between the said terminal and the said access point.