Near-Optimal Cross-Layer Forward Error Correction Using Raptor and RCPC Codes for Prioritized Video Transmission Over Wireless Channels

摘要

Cross-layer forward error correction (FEC) aims at utilizing available bandwidth more efficiently, which has been applied to error-prone video transmission over imperfect wireless channels. In this paper we propose a new near-optimal cross-layer FEC scheme in which systematic Raptor codes are used at the application layer and rate compatible punctured convolutional (RCPC) codes are used at the physical layer for H.264/AVC encoded video streaming with channel bandwidth constraints. In the proposed scheme, in order to fully exploit the unequal importance of compressed video data, we assign each source packet a different priority according to its contribution to the reconstructed video quality. We first obtain the transmission parameters, which satisfies the conditions for optimal video transmission, for the optimal cross-layer Raptor-RCPC FEC in the ideal situation through a theoretical analysis, and then we propose a heuristic algorithm searching from the optimal solution point to obtain the transmission parameters, which are near optimal in the practical situation. Computer simulation results show that the proposed scheme can achieve significant performance improvements in both the additive white Gaussian noise and Rayleigh channels compared with the previous work.