TCM For Frequency-Selective, Interleaved Fading Channels Using Joint Diversity Combining

The severity of frequency-selective fading channels necessitates the combining of multiple diversity sources to achieve acceptable performance. Traditional techniques often perform the combining of different sources of diversity separately, resulting in significant performance degradation. Recently, algorithms for the joint optimal combining were reformulated in a form suitable for practical implementation. In this paper we investigate the applicability of these algorithms for the specific problem of interleaved TCM systems in frequency-selective fading channels with or without external diversity. It is demonstrated that soft-decision equalization techniques are necessary and sufficient for the application of TCM techniques over such channels. In addition, it is shown that the design trade-offs associated with the resulting TCM techniques are significantly different than those associated with memoryless channels.