Rate-Optimization for Scalable Video Transmission over Wireless Networks

In this paper, we present a rate-optimization procedure for the transmission of scalable video sequences (e.g., the scalable extension of the H.264/AVC standard), over wireless channels. In particular, we propose a method of specifying the extractable rate points in the scalable bit stream such that the expected transmission rate is increased and the probability of not transmitting any video layer is reduced. The problem is formulated as an optimization problem. Although the problem is non-linear and non-convex, we show through simulations that it is possible to converge to the global optimal solution using numerical methods provided adequate initialization points are chosen. The low complexity of the numerical methods make such approaches suitable for rapidly changing environments. It is further demonstrated through simulations that, for given channel conditions, a limit on the level of granularity of the scalable video stream exists, beyond which the increase in the expected transmission rate is minimal, but a reduction in the compression efficiency is inevitable.