Evaluation of MPEG-4 video streaming over UMTS/WCDNL4, dedicated channels

Universal mobile telecommunications system (UMTS) is a third-generation mobile communication system that supports wireless wideband multimedia communications. This paper investigates the performance of streaming MPEG-4 video over UMTS dedicated channels with varying channel conditions. In order to evaluate the performance, simulation models for UMTS and MPEG-4 were developed. Simulation results show that UMTS radio control link (RLC) protocol operating in the acknowledged mode outperforms the unacknowledged mode. The latter mode provides timely delivery but no error recovery. The acknowledged mode can deliver acceptable video quality for RLC block error rates up to 40% utilizing a pre-decoder buffer. We also discover that RLC block size can affect the video quality with a larger RLC block size attaining better quality. However, the optimum RLC block size is dependent on the encoded video frame size and the channel bit rate. Therefore, the RLC block size can be tuned to a proper value given the encoded video frame size and channel bit rate.