Cooperative Resource Management by Access Points and Stations for Fair and Efficient Sharing of Wireless LANs

The future network will consist of heterogeneous ones, and wireless networks will play a more important role there in providing pervasive services. Our major concern is to develop a way of achieving efficient and fair share of resources in the wireless network, which is built of various equipments. In this regard, one of the significant issue for each station (STA) is how to select an appropriate access point (AP) among available APs in the wireless LANs in order to effectively use those multiple APs, namely, which STA should be accommodated by which AP. In the systems widely deployed currently, each STA straightforwardly and autonomously selects its AP based upon received signal strength (RSS). However, this can result in a concentration of STAs at specific APs, and thus degrade the fairness property in achievable throughput of each STA. We have already proposed a cooperative scheme for APs and STAs in order to attain efficient and fair sharing of resources, and have developed the prototype system. APs provide some information on resource utilization, i.e., the number of active STAs, while STAs autonomously select their appropriate APs by using both the information and RSS. In the present paper, we further investigate two cooperative resource management schemes; in both schemes, each AP broadcasts information on the number of active STAs at fixed time intervals. In one scheme, the information provided is based upon just a single snapshot measurement (SSM) for a particular duration, while it is based on the exponentially weighted moving average with flip-flop filter (EWMA/FF) in the other scheme. EWMA/FF moderates the information to avoid having too many STAs concentrating at specific APs if that changes drastically, while EWMA/FF behaves like SSM otherwise. This successfully leads to fair and efficient sharing of wireless resource.