Robust mobile video transmission using DSTS-SP via three-stage iterative joint source-channel decoding

Abstract

The last decade has witnessed a great growth in the number of cellular users, and consequently there is a prominent inclination towards wireless and mobile communication by the researchers. This research work considers the optimization of joint source and channel coding for the H.264/AVC (advanced video coding) stream. The source encoded video is serially transmitted using concatenated source bit coding (SBC) assisted by Rate-1 Precoder through a non-coherent differential space-time spreading (DSTS) scheme with multidimensional sphere packing (SP) modulation. More specifically, the Precoder is invoked as an intermediate encoder having an infmite impulse response which assists in the distribution of information across the decoders. Furthermore, the Precoder enhances the iterative decoding performance by splitting the overall system's iteration into inner and outer iterations. The H.264/AVC stream is highly compressed and yields residual redundancy which limits the iterative decoding performance. Therefore, for enhancing the performance of iteratively decoded systems, artificial redundancy is incorporated along the video bit stream using the SBC. Specifically, the iterative decoding provides better bit error ratio and also enhances the perceptual peak signal-to-noise ratio (PSNR) metric. Extrinsic information transfer (EXIT) chart analysis is done to measure the convergence behavior of our proposed system. The effect of minimum Hamming distance (d(H,min)) on the attainable performance of the joint source-channel coded video sequence is investigated. Quantitatively, our proposed DSTS - SP - Precoder - SBC[5 15] scheme having d(H,min) = 6 exhibits a noticeable improvement of about 22 dB gain at the PSNR degradation of 2 dB, against the DSTS - SP - Precoder - SBC[2 6]* benchmarker having d(H,min) = 1 for the correlated Rayleigh fading channel.