A new access point selection policy for multi-rate IEEE 802.11 WLANs.

IJPEDS 01/2008; 23:291-307. DOI: 10.1080/17445760801930914
Source: DBLP

ABSTRACT In wireless local area networks often a station can potentially associate with more than one access point. Therefore, a relevant question is which access point to select \best" from a list of candidate ones. In IEEE 802.11, the user simply associates to the access point with the strongest received signal strength. However, this may result in a signican t load imbalance between several access points. Moreover, the multi-rate exibilit y provided by several IEEE 802.11 variants can cause low bit rate stations to negatively aect high bit rate ones and consequently degrade the overall network throughput. This paper investigates the various aspects of \best" access point selection for IEEE 802.11 systems. In detail, we rst derive a new decision metric which can be used for AP selection. Using this metric we propose two new selection mechanisms which are decentralized in the sense that the decision is performed by each station, given appropriate status information of each access point. In fact, only few bytes of status information have to be added to the beacon and probe response frames which does not impose signican t overhead. We show that our mechanism improves mean quality of service of all stations and better utilizes network resources compared to the conventional one implemented today in IEEE 802.11 devices. Also, the schemes are appealing in terms of stability and provide their performance improvement even for denser or lighter network congurations.

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