Closed-form average BER expression for chip-interleaved DS-CDMA system conducting M-ary communication and noncoherent demodulation in flat Rayleigh fading channel

Closed-form expression of average Bit Error Rate (BER) is developed for Chip-Interleaved DS-CDMA system that conducts M-ary communication and non-coherent demodulation in AWGN channel with flat Rayleigh fading. The transmitter uses BPSK modulation and employs binary pseudo-random sequences for symbol-spreading. In receiver the non-coherent demodulation is based on the optimal quadrature demodulator to cancel the phase angles of received signals. Numerical results of simulations greatly agree with the analytical results of the developed expression.