Comparison of BER Performance of a WCDMA System in Rayleigh fading and AWGN Channels at Different Data Rates

Abstract

The Third Generation systems (3G) that have been implemented by mobile service providers have provided more benefits compared to the second generation systems. The 3G technology delivers services such as video streaming, internet, 3D games to the users at a very reliable rate. However, the signal encounters interference in the channel which can be Rayleigh fading or additive white Gaussian channel during transmission. The interference degrades the signal which gives rise to some bits being received in error. The performance of any given system is determined by its bit error rate (BER). When the BER is low the better the quality of the services offered by the system. This paper has developed a wideband code division multiple access (WCDMA) system model which can transmit data from 64kbps to 2Mbps in a Rayleigh fading and AWGN channels. The BERs are calculated at the receiver section for each channel and a comparison done for the two channels with or without error correction. The computer simulation tool (MATLAB) was used to develop and evaluate the bit error rate (BER) performance of the system. The model is developed in Simulink which has blocks in the communication block set which have parameters for simulation of the
system. The error rate is calculated at the receiver by comparing the number of bits received in error to the total number of bits that is transmitted. The performance of the WCDMA is better in Rayleigh fading channel compared to the AWGN channel. The improvement
of performance in a given system means an additional capacity in the channel and hence more users accessing the channel.