Block codes with soft-decision trellis decoding in compressed image transmission over Rayleigh fading channel

We propose an efficient error control technique for compressed image communication over a Rayleigh fading channel. The maximum-likelihood decoding in combination with soft-decision gives full play to the error correcting capabilities of block codes. By adopting the concept of the generalized array code (GAC), the trellis decoding complexity is greatly reduced at the same time. The performance of several GAC-based block codes is studied over a Rayleigh fading channel and important conclusions are drawn. When applied to image transmission, this scheme improves the system performance significantly. At bit error rates around 10^-5 a 34 dB coding gain can be obtained by the code (15,5,7), with a short time delay guaranteed due to the short code length