Interference on multipath QoS routing for ad hoc wireless network

Mobile nodes are interconnected by multihop routing paths consist of unstable radio links in ad hoc wireless network. It is complex and difficult to provide QoS routing in such network because of imprecise network information, insufficient bandwidth and dynamic topology. For improving network stability and total throughput, multiple paths routing protocols are proposed. A sender will discover multiple disjoined routing paths and dispatch traffic into them according to their bandwidth or delay. For multimedia applications, unstable network throughput or insufficient bandwidth will invite delay or jitter when multimedia presentation. Allocating and reserving enough bandwidth, and preserving stable network throughput, are important and complicated issues in ad hoc wireless multimedia network. Some multipath protocols preevaluate available bandwidth paths and select enough total bandwidth if the application asks for QoS constraint. These disjoined paths with smaller hop-counts are general too closed with each other if we try to minimize the network cost. Furthermore, the total bandwidth of those paths cannot just be sum up because of "interference". Discovering and selecting multiple high-interfering paths is ineffectual through the total bandwidth is not precise. We discuss the "available bandwidth", network capacity and "interference" according to different Media Access Control (MAC) protocols. A concept of "interfering ratio" of multipath are discussed and a simulation shows the properties of multipath interfering.