QoS Access Points Placement with Fault Tolerance in Wireless Local Area Networks

Abstract

In this paper, we study the problem of enhancing the fault tolerance of IEEE 802.11 wireless local area networks in the design stage. We aim to settle proper number of access points (APs) and carefully locate them, such that the system can tolerate AP failures while guaranteeing QoS requirement. Given a set of clients (end-users), each client has a traffic demand for Internet access. The problem of our concern is to find out the minimal number of access points and proper location, such that the fault tolerance and QoS constraint are both satisfied. That is, when there is no AP failure, the actual traffic delivery ratio for each client shall exceed the threshold. When their happens that one AP failed, the clients it served can switch to other APs with reconfiguration of the system, while providing an acceptable bandwidth. We proposed a heuristic algorithm, firstly we place one AP in each candidate place and gradually decrease the APs until no more APs can be deleted, in each step we make fault tolerance checking. Our proposed method can effectively solve the problem of tolerating to access point failure in the design phase of wireless local area networks. Simulations are conducted to show the performance of our proposed method.