On the Selection of Scanning Parameters in IEEE 802.11 Networks

In this paper, we study the IEEE 802.11 discovery process needed for handovers and propose an adaptive scanning strategy based on application requirements. The scanning process consists in actively probing the radio channels to gather access points information. We consider a well decoupled situation in which the scanning latency, the scanning failure rate and the number of discovered access points define the scanning performance. We model these scanning metrics by analytical expressions to represent the performance trade-off, i.e., finding the largest number of access points with a minimum latency. We present a novel approach based on a multi-objective optimization approach to obtain the optimal number of channels to scan, the optimal channel sequence and its correspondent scanning timers. Finally, we compare one fixed and two adaptive scanning approaches by means of simulations. We show that our adaptive scanning strategies better manage the performance trade-off and allow different application profiles to match with specific scanning latency.