Iterative Detection Aided H.264 Wireless Video Telephony Using Irregular Convolutional Codes

In this paper we evaluate the performance of a data-partitioned (DP) H.264 coded video transmission system using unequal error protection (UEP) irregular convolutional codes (IRCC). Using UEP, perceptually more important bits are provided with more strong protection relative to less important bits. An iterative detection aided combination of IRCC and a rate-1 precoder was used to improve the overall BER performance and to enhance the objective video quality expressed in terms of peak signal-to-noise ratio (PSNR). The effect of different error protection schemes on the attainable system performance is demonstrated, while keeping the overall bit-rate budget constant for the transmission of DP H.264 source coded video over correlated narrowband Rayleigh fading channels. In this paper we exploited the high design flexibility of IRCCs, which constitutes a family of different rate subcodes, while maintaining an excellent iterative decoding convergence performance. Additionally, due to the use of different-rate subcodes, IRCCs have the capability of providing UEP for the H.264 coded video stream. An EXIT chart matching procedure was used for the design of our specific IRCC. Additionally, EXIT charts were used for analysing the attainable system performance of various error protection schemes employed. Explicitly, our experimental results show that the proposed UEP scheme using IRCC outperforms its equal error protection (EEP) counterpart employing regular convolutional codes by about 0.5 dB E_b/N_o at the PSNR degradation point of 1 dB.