A multipath video delivery scheme over diffserv wireless LANs

Abstract

This paper presents a joint source coding and networking scheme for video delivery over ad hoc wireless local area networks. The objective is to improve the end-to-end video quality with the constraint of the physical network. The proposed video transport scheme effectively integrates several networking components including load-aware multipath routing, class based queuing (CBQ), and scalable (or layered) video source coding techniques. A typical progressive video coder, 3D-SPIHT, is used to generate multi-layer source data streams. The coded bitstreams are then segmented into multiple sub-streams, each with a different level of importance towards the final video reconstruction. The underlay wireless ad hoc network is designed to support service differentiation. A contention sensitive load aware routing (CSLAR) protocol is proposed. The approach is to discover multiple routes between the source and the destination, and label each route with a load value which indicates its quality of service (QoS) characteristics. The video sub-streams will be distributed among these paths according to their QoS priority. CBQ is also applied to all intermediate nodes, which gives preference to important sub-streams. Through this approach, the scalable source coding techniques are incorporated with differentiated service (DiffServ) networking techniques so that the overall system performance is effectively improved. Simulations have been conducted on the network simulator (ns-2). Both network layer performance and application layer performance are evaluated. Significant improvements over traditional ad hoc wireless network transport schemes have been observed.