Coding and modulation schemes for slow fading channels

Two new schemes are presented to improve the error performances of coding and modulation on slow fading channels. The first scheme consists of permuting coordinates of multidimensional modulation and trellis coded modulation (TCM) on interleaved channels. Theoretical and simulation results show that this simple permutation may provide gains of 3.8 dB on slow Rayleigh fading channels for uncoded modulation. It also improves by 5 dB the performance of fully interleaved 16-QAM TCM. The second scheme consists of using coded frequency diversity. Without bandwidth expansion, the signal is spread over different independent fading channels. For two very slow fading channels, where interleaving is impractical and coding usually does not provide any gain, coded diversity and 16-QAM TCM provides gains of 13 dB at a BER of 10/sup -4/.<>