Error performance of pilot-symbol aided direct-sequence spread spectrum Q-PSK in Rayleigh fading channels with antenna diversity reception

The advantages and feasibility of applying antenna diversity reception technique for pilot-symbol aided direct-sequence spread spectrum (PSA DS/SS) Q-PSK transmission system are investigated in fading environments. Both post-detection and pre-detection antenna diversity techniques with various methods, such as maximal-ratio combining and switching diversity, are considered in the study. The average bit error probability of PSA DS/SS Q-PSK transceiver system with antenna diversity reception is evaluated by SPW software simulation platform. In the simulation, frequency-nonselective Rayleigh fading channels with the effect of Doppler frequency shift plus additive white Gaussian noise (AWGN) are assumed and a single-finger RAKE receiver is applied to the receiver structure. Based on the simulated bit error probabilities, a performance comparison between different diversity receiver structures is presented. The effects of transmit slot length and channel variation on the system performance are investigated. The error performance degradation due to coherent demodulation, using practical channel estimation techniques, such as 2-slot pilot symbols averaging and linear interpolation, under various kind of fading conditions are also considered