Layered video streams over wireless ad hoc campus networks

This paper presents a new transport scheme for layered video streams over wireless ad hoc networks. An efficient 3-D subband video coder is used in generating multi-layer source data streams. ne underlay wireless ad hoc network is specially designed for a campus environment. The video coding algorithm features a 3-D symmetric lapped transform for both spatial and temporal decorrelation. Its block based bitplane coding procedure generates progressive bit streams that can be segmented into multiple resolution layers. In ad hoc network, a class based queuing (CBQ) mechanism is employed to provide differentiated services (Diff-Serv) for different data stream layers. This integrated networking system prioritizes the layers for lower resolutions or with higher error sensitivities, so that they will experience less delay or packet loss in case of congestion or link breakage. Through this approach, the advantage of progressive source coding is effectively exploited, and it is incorporated with DiffServ networking technique to improve the overall system performance. Simulations have been conducted on the network simulator (ns-2), and some results are presented in this paper.