Combined turbo equalization and turbo decoding

In this paper, the subject of turbo coding in the presence of intersymbol interference channel is investigated. An iterative decoder structure is presented, which combines the channel equalization and the turbo decoding. At each iteration extrinsic information from the channel detector is fed into the turbo decoders, and then their extrinsic information is fed back to the channel detector. Simulation results are presented for turbo code with BPSK and and PSK modulations, transmitted over several ISI channels having severe frequency distortion. The performances are about 1 dB from the ISI channel capacity at bit error rate of 10^-5