Bandwidth Allocation in IEEE 802.11 WLANs in presence of Inter-BSSs Hidden Terminals

Due to the limited number of orthogonal channels and the dense deployment of IEEE 802.11 access points (APs), interference between neighboring basic service sets (BSSs) are very common in indoor environment. One consequence of such neighboring interference is the inter-BSSs hidden terminal problem in which some mobile stations may suffer from throughput starvation. In this paper, we advocate and develop a methodology to allocate bandwidth as a mean of combating such starvation problem. We first propose an analytical model to study the interaction between contending links in the network, then based on this model, we demonstrate how the contention window (CW) can be adjusted in order to allocate the upload and download bandwidth to sustain some predefined bandwidth requirement with only the basic access scheme is used. Our approach does not require any hardware modification, and is compatible with most WLAN chipsets. The optimal window setting can be obtained by simply solving a nonlinear system once without any iterative algorithm. Simulation are invoked to support the effectiveness of the proposed methodology in achieving the target bandwidth even under saturation condition.