Priority-based real-time stream coding over multi-channel under sliding window erasures

摘要

Multi-channel technology can be used to provide higher transmission ability to the bandwidth-intensive and delay-sensitive real-time streams. However, traditional channel capacity theories and coding schemes are seldom designed for the real-time streams with strict delay constraint, especially when multiple channels are used. This paper considers a real-time stream system, where real-time messages with different importance should be transmitted through several packet erasure channels, and be decoded by the receiver within a fixed delay. We introduce the concepts of Symmetric Real-time (SR) stream and Asymmetric Real-time (AR) stream according to the stream characteristics. The multi-channel transmission capacities are derived for SR and AR streams under sliding window erasures, which can be used to guide the design of efficient real-time stream coding approaches. A Maximum Equilibrium Intra-session Code (MEIC) is presented for SR and AR streams, and is shown asymptotically able to achieve the corresponding transmission capacities. Finally, the performance of MEIC is verified by simulations.