Multipath simulation models for mobile radio channels

Several ray models with various delay profiles are analyzed to study their statistical compatibility with natural fading events and evaluated in terms of irreducible BER caused solely by the time delay spread. The results obtained from the analysis and computer simulation suggest that two-ray delay model (American Digital Cellular Standard) yields the worst-case BER performance compared to larger ray models with the same amount of RMS delay spread. For identical signal-to-ISI ratio yields lower irreducible BER. The results were obtained for coherent QPSK modulation. It is also shown that they can be readily applied for BPSK, π/4-QPSK or GMSK