On fairness and efficiency of adaptive audio application layers for multihop wireless networks

In this paper we investigate the effectiveness of simple adaptive application layers for multimedia streaming over multi-hop ad-hoc networks. Extensive simulations are presented using our hybrid simulation platform. By using the coefficient of variation we report on fairness issues associated with the end-to-end adaptation. Fairness in server rates and effective bandwidth distribution among the connections is significantly increased as adaptivity is introduced. At a connection level we show that when a timeout mechanism exists in the adaptation mechanism, the end-to-end feedback mechanism can deliver a consistent view of the RTP loss rates at the server at low mobility and low hop count, even in the presence of high competing traffic. The highly oscillatory nature of the loss rates remains for adaptive connections. We argue that a redundant speech captioning scheme is necessary in such conditions. In summary, when connections are adaptive in multi-hop networks perception, efficient bandwidth usage, and fairness is enhanced