Performance of simulcast systems in mobile radio environments

Simulcast paging systems are considered, where the differential propagation delays to a receiver from different transmitters can cause severe intersymbol interference. Two simulcast paging systems are evaluated, denoted by Systems A and B. System A uses Gaussian minimum shift keying (GMSK) with a channel bandwidth of 12.5 kHz, whereas System B uses 4-level FM with a channel bandwidth of 25 kHz. With simulcast systems, it is important to identify the maximum tolerable differential delay. For this purpose, the simulcast channel is modeled as a two-ray fading channel, where each ray is independently Rayleigh faded. Performance results are obtained while varying the differential delay and power ratio between the two rays, and the Doppler spread.