Priority-Aware Joint Packet Fragmentation and Error Protection Scheme for H.264 Video over Wireless Channels

Abstract

We present a real-time, priority-aware joint packet fragmentation and error protection scheme for transmitting H.264/AVC compressed video over Rayleigh fading channels. A priority is assigned to every video slice based on the predicted cumulative mean squared error (CMSE) contributed by its loss relative to all the slices of the group of pictures (GOP). Here, the CMSE of a slice, which is predicted by using our low-complexity generalized linear model, represents the degradation in video quality contributed by its loss. The slices of a frame belonging to the same priority are aggregated to form video packet(s). We simulate the fragment error rates (FERs) for a combination of different fragment sizes and rate compatible punctured convolutional (RCPC) code rates. These FERs are then used to determine the optimal fragment sizes and code rates for packets of each priority class by minimizing the expected normalized predicted CMSE of all the priority classes per GOP in H.264 video bitstream. We observed a significant improvement in the received video quality over the conventional and priority-agnostic packet fragmentation schemes.