Power controlled wireless links for video streaming applications

We propose a novel modelling framework to investigate video streaming over wireless links. The video server (transmitter) encodes and transmits video frames to a client (receiver) over a fluctuating wireless channel. The objective is to find the optimal transmission power, rate and video encoding option (intra-mode or inter-mode) for each video frame in order to minimize the total transmission power (energy) consumption, while achieving a certain level of received video quality. The latter is measured by the distortions due to frames missing their playtimes (i.e. deadlines) and error propagations due to inter-coded frames. Using dynamic programming methodology, we formulate the optimality equations and obtain the optimal transmission/encoding scheme. Through extensive simulations, we observe that the proposed cross-layer scheme reduces power consumption by 50% to 75% over the benchmarks while achieving the same video quality. Using a H.26L codec, we further show the proposed scheme increases the media quality by more than 10 dB in PSNR over the benchmarks with the same power constraints.