Multiple-symbol differential detection of π/4 QPSK over land mobile satellite communications channels

Multiple symbol differential detection of π/4 QPSK in land mobile satellite communication channels (modeled as correlated Rician fading) is studied. BER performance of this scheme in land mobile satellite communication channels are evaluated using union bounds of pairwise bit error probabilities for situations of ideal channel information and no channel information. It has been found that in light or medium fading Rician channels, about a 1 dB gain in E_b/N _o at a BER=10^-4 can be achieved by using four-symbol differential detection instead of conventional two-symbol differential detection. It is also proved that multiple-symbol differential detection is not suitable for severe fading Rician channels or Rayleigh channels. The influence of the fading rate on the BER performance is also evaluated. Part of the results are compared with those from previous literature