A sub-optimal receiving scheme for SCCC with coded MSK over ISI channels

In this paper, we investigate serial concatenated convolutional codes (SCCC) with coded MSK over inter-symbol interference (ISI) channel. We propose a sub-optimal receiving scheme and study its performance using Monte Carlo simulation method. For SCCC with coded MSK, to achieve the best performance at the receiver, one needs to combine the inner encoder and the ISI channel to create a super trellis and use ML or symbol-by-symbol MAP to decode. However, the decoding complexity of this method increases exponentially with respect to the ISI length. In practice, it is desirable to sacrifice optimality for computational efficiency. To reduce the complexity of the decoder, we use an equalizer to compensate for the effects of ISI. Two equalization algorithms, zero-forcing and least mean square algorithms are studied. The simulation results show that the least mean square algorithm gives better performance than zero-forcing algorithm.