We obtain an association policy for STAs in an IEEE 802.11 WLAN by takinginto account explicitly two aspects of practical importance: (a) TCP-controlledshort file downloads interspersed with read times (motivated by web browsing),and (b) different STAs associated with an AP at possibly different rates(depending on distance from the AP). Our approach is based on two steps. First,we consider an analytical model to obtain the aggregate AP throughput for longTCP-controlled file downloads when STAs are associated at k different rates r1,r2, : : :, rk; this extends earlier work in the literature. Second, we presenta 2-node closed queueing network model to approximate the expectedaverage-sized file download time for a user who shares the AP with other usersassociated at a multiplicity of rates. These analytical results motivate theproposed association policy, called the Estimated Delay based Association (EDA)policy: Associate with the AP at which the expected file download time is theleast. Simulations indicate that for a web-browsing type traffic scenario, EDAoutperforms other policies that have been proposed earlier; the extent ofimprovement ranges from 12.8% to 46.4% for a 9-AP network. To the best of ourknowledge, this is the first work that proposes an association policy tailoredspecifically for web browsing. Apart from this, our analytical results could beof independent interest
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