Performance improvement of a CDMA physical layer over Rayleigh fading channels

This paper investigates performance of a CDMA physical layer based on TIA/EIA/IS-95A over correlated flat and frequency-selective fading channels in the presence of channel interleaving. The effect of mobile speed on frame error and bit error rate (FER and BER) is taken into account by changing the Doppler frequency. The properties of CDMA spreading codes are used in improving the signal-to-noise ratio at the RAKE receiver by resolving the multipath components. The performance of IS-95A reverse link power control is evaluated. A soft-decision Viterbi decoder is used with non-coherent orthogonal demodulation. Simulation results for FER and BER using different code rates in the convolutional encoder are obtained. The performance of various types of channel interleavers for different fading conditions is evaluated. The tradeoff between FER and bandwidth efficiency by puncturing the base rate convolution code is considered. Some simulation results for TIA/EIA/IS-99, a data standard for CDMA are given. These serve as criteria for deciding upon the tradeoff. A method for increasing TCP bit-rate throughput for IS-95A-based data standards is suggested.