Video transmission over wireless networks

Abstract

This paper addresses the problem of source-rate control in video streaming over wireless networks. The wireless channel resources are assumed to be shared among a variable number of stations using a contention-based access mechanism. In this context, the resulting throughput available for the video server has been proved to be bursty, which is a feature that makes the high-quality video streaming quite difficult. To face the channel burstiness, we propose a solution that focuses on the fluidity of the video playback by controlling the occupancy of the playback buffer so as not to exceed a desired rate of buffer starvation occurrences. While this constraint has been guaranteed, the encoder maximizes the source bit rate. Rate control is performed adaptively on the basis of a per-interval approach, which has the advantage to reduce the fluctuations in the source bit rate, ensuring smooth variations in video quality and avoiding the "saw" effect that is typically observed in frame-based rate control. Because of its low computational complexity, the proposed scheme is attractive for real-time operation. Simulations are carried out to assess the performance of the proposed scheme.