Abstract：Focusing on coherent DS-SS/MPSK system in single path slow fading channel model, this paper analyzes the effect of frequency offset on system performance, and the closed-form Bit Error Rate (BER) expressions are also obtained. Firstly, the Signal Noise Ratio (SNR) characteristic of matched filter despread symbol and the distribution of coherent phase estimation error are derived. Secondly, the exact integration formula of BER for fading channel is presented, moreover, by using the Maclaurin series expansion of MPSK conditional Symbol Error Rate (SER), the simplified BER approximations for BPSK and QPSK are derived over AWGN, Nakagami-m fading and Rayleigh fading channel. Finally, numerial results show that the approximations provide excellent accuracy without loss and can be applied to practical system design and performance evaluation.
2006, Vol. 28 
