Cross layer access point selection mechanisms for a distributed queuing MAC protocol

Abstract

The Distributed Queuing with Collision Avoidance (DQCA) Medium Access Control (MAC) protocol has been presented in the literature as a high-performance protocol for WLANs. Previous work regarding DQCA is focused on the operation of a single cell, where no interaction with neighboring sites is considered. In this paper, we define specific handoff procedures (channel sensing, discovery and reassociation functions) that enable the roaming of users in a scenario consisting of several DQCA access points (APs) deployed in a specific area using non-overlapping channel frequencies. Furthermore, we introduce a number of AP selection mechanisms in order to provide efficient reassociation decision criteria in the context of DQCA. These mechanisms are based either on a single metric such as the Signal to Noise Ratio (SNR) or the traffic load, or on cross-layer design by combining the information from different layers. Finally, our proposed solutions are evaluated by means of computer simulations.