Loss compensation using route diversity in wireless multicast

The demand for content distribution services via wireless local area networks has been increasing. A multi-cell structure, which consists of multiple access points (APs), is more suitable for distributing content in wider areas. However, in multicast, there had been an unsolved issue; how to compensate for data-frame loss for each user. In particular, in wireless links, loss compensation techniques are essential because of the high loss-rate. To solve this problem, several loss-compensation methods have been proposed. Retransmission from AP, including automatic repeat request, is not always effective because the time-diversity effect cannot be obtained in static environments, where channel conditions are not time varying ones. Another approach for this problem is retransmission from other stations that have successfully received the data-frame, which is effective even in a static environment because of the route-diversity effect. In this paper, we propose a novel loss compensation method that uses retransmission from successful stations, and we also present the design of the medium access control layer. Our method aims at loss compensation for failure stations near borders between adjacent cells because the failed rate increases as the distance from APs is larger. The performance of the method is evaluated through computer simulations.