BER IMPROVEMENT OF PRCPM IN MOBILE RADIO CHANNELS WITH DISCRIMINATOR DETECTION USING DECISION FEEDBACK EQUALIZATION

Some digital partial response continuous phase modulation (PRCPM) signals such as 3RC, 4RC, 3SRC, and 4SRC have compact power spectra. However, their bit error rates (BER) in the mobile radio channel, where the maximum Doppler shift can reach 0.005 times the bit rate, are high when a simple discriminator is used for detection. This is due to the high intersymbol interference (ISI) resulting from adjacent bits. Improving the BER performance by using decision feedback equalization (DFE) to cancel the effect of one adjacent bit is theoretically investigated in this paper. A closed form expression for the average probability of error as a function of the Doppler shift is derived for discriminator detection with decision feedback. Numerical results are presented to compare the BER performance of discriminator detection with and without feedback equalization.