An outage compensation algorithm for WLANs

In this paper we propose an algorithm to address the emergency case of an access point (AP) failure by adjusting a radio parameter of the neighboring APs. The goal is to minimize the coverage gap while at the same time: a) restrain imposed interference as much as possible and b) provide adequate load fairness among the APs. We assume an 802.11 infrastructure network where initially every mobile terminal (MT) can connect to at least one AP even when all APs are transmitting at the minimal power level. The algorithm uses a fuzzy inference system with the following inputs: a) the compensating AP´s load and b) a metric of the overlapping area that each compensating AP creates with the neighboring APs. The output is the transmission power increase of the compensating APs.