Wireless links pose a significant challenge for sending video streams. This is due to the fact that current generation wireless links have low bit rate and high error rate compared to wire-line links. To send high bit rate delay-sensitive traffic over a wireless link, suitable video compression algorithms and transport/link layer protocols are needed. We have built a wireless video system using an off-the-shelf error resilient low bit rate video codec with our implementation of UDP Lite and PPP Lite, which are modifications to transport and link layer protocols respectively. The flexible checksumming schemes in these protocols allow error-resilient policies at the application to be reflected in the networking stack. We conducted simulations and experimental evaluations of this wireless video system using both quantitative performance metrics ---throughput, jitter, packet loss, and end-to-end latency--- and viewer perception of quality ---smooth motion, changes in luminance, and image distortion.
Almudena Konrad, Amoolya Singh