Performance analysis of CDMA mobile systems using antenna arrays and multi-user detection

An antenna array-based receiver for wireless direct sequence-CDMA with coherent multi-user detection has been studied. The receiver consists of a front-end beamformer for every user in the cell and has knowledge of all users' signature sequences. The beamformer uses the existing code-filtering approach to estimate the desired user channel vector, enhancing its signal and reducing the co-channel interference from other directions. The average uncoded bit error rate (BER) as a function of the number of active users, the average antenna signal-to-noise ratio (SNR), and the number of receiving antennas is examined in a Rayleigh fading channel. Analysis show an increase in system capacity proportional to the number of antennas.