BER performance of QDPSK with postdetection diversity reception in mobile radio channels

摘要

The bit-error-rate performance of Nyquist raised-cosine-filtered quaternary differential phase shift keying (RC-QDPSK) and pi /4-shift RC-QDPSK with postdetection diversity reception is theoretically analyzed for Rayleigh fading channels. A selection combiner, equal-gain combiner, and maximal-ratio combiner are considered for postdetection diversity reception. Diversity improvements on the average BER due to additive white Gaussian noise, cochannel interference, random FM noise, and delay spread of the multipath channel are calculated. Also analyzed is the combined effect of diversity reception and error control. The required E/sub b//N/sub 0/ and allowable RMS delay spread for achieving a certain BER and spectrum efficiency in cellular mobile systems are calculated when short BCH forward error correcting codes are used. The performance of automatic repeat request combined with time diversity reception is investigated.