DS-SSMA star network over indoor radio multipath Rician fading channels

The authors investigate the bit error rate (BER) performance of a direct-sequence spread-spectrum multiple-access (DS-SSMA) star network operating over a multipath Rician fading channel (which models indoor radio propagation in factories). They consider both phase-shift-keying modulation with coherent demodulation and differential phase-shift-keying modulation with noncoherent demodulation. Predetection multipath diversity (maximal ratio combining for coherent reception and equal gain combining for noncoherent reception) and simple channel coding are used for improving the BER performance. Numerical results for the BER of both coherent and noncoherent systems show that predetection multipath diversity plus coding is a very efficient technique for improving the BER performance of systems over multipath Rician fading channels and that, for the indoor radio channels in factories, the noncoherent system is preferable