Error rate prediction for NCFSK digital mobile radio systems

Error performance analysis for the VHF digital mobile radio system is presented. The binary frequency-shift keying (FSK) system using noncoherent (NC) demodulation, with a limiter/discriminator receiver, is considered. All major error-causing factors, such as signal fading, Gaussian and impulsive noise, are taken into account and the corresponding general expression for the error probability is derived. This expression is then applied to the bit error rate (BER) evaluations for the three adequate receivers, described by the different mathematical models of their impulse responses. The calculated BER values are compared to the results obtained by measurements on the real laboratory models simulating the mobile radio systems considered. In conclusion, the mathematical model for the receiver impulse response yielding the best prediction results, when using the derived expression for the BER calculation, is proposed.