Convergence Behaviour of Iteratively Decoded Short Block-Codes in H.264 Joint Source and Channel Decoding

• Published in: VTC Spring 2009 - IEEE 69th Vehicular Technology Conference pp. 1 - 5
• Main Authors: Nasruminallah, Hanzo, L.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.04.2009
• Subjects: Bit error rate; Block codes; Convergence; Design optimization; Fading; Information analysis; Iterative decoding; Narrowband; Protection; PSNR
• ISSN: 1550-2252
• DOI: 10.1109/VETECS.2009.5073461

We propose a novel class of short block codes (SBCs) designed for guaranteed convergence to an infinitesimally low bit error ratio (BER), which relies on the joint optimisation of soft-bit assisted iterative source and channel decoding. An iterative detection aided combination of SBC assisted soft-bit source decoding (SBSD) and a rate-1 precoder was used to evaluate the attainable performance of the proposed scheme for transmission of data-partitioned (DP) H.264 source coded video over correlated narrowband Rayleigh fading channels. Additionally, we demonstrated the effects of different SBCs having diverse minimum Hamming distances [d H,min ] but identical coding rates on both the overall BER performance as well as on the objective video quality expressed in terms of the Peak Signal-to-Noise Ratio (PSNR). The convergence behaviour of the iterative decoding scheme using SBCs as a function of d H,min is analysed by utilising extrinsic information transfer (EXIT) charts. Explicitly, our experimental results show that the proposed error protection scheme using SBCs associated with d H,min = 6 outperforms the identical-code-rate SBCs having d H,min = 3 by about 3 dB at the PSNR degradation point of 1 dB. Additionally, an E b /N o gain of 27 dB is attained using iterative soft-bit source and channel decoding with the aid of rate-1/3 SBCs relative to the identical-rate benchmarker.