Joint source channel coding over channels with intersymbol interference using vector channels and discrete multitone

We investigate joint source channel coding for channels with intersymbol interference (ISI) where the source coder is a vector quantizer. In our previous work we used a block MAP equalizer, which takes into account the residual correlation between the VQ outputs and also provides for soft decisions to improve the performance. In this paper we propose the use of a vector channel approach and discrete multitone modulation for joint source channel coding on channels with ISI. Using these modulation procedures, intersymbol interference can be eliminated and the problem of joint source channel coding for ISI channels is reduced to the problem of coding for vector Gaussian channels. Optimization of the signal set is performed through optimal power allocation to the subchannels. Simulation results are presented for both vector and discrete multitone channels and compared to the results obtained by using the block MAP equalizer and to the OPTA (optimum performance theoretically attainable) bound.