Adaptive beamforming for DS-CDMA using conjugate gradient algorithm in a multipath fading channel

An antenna array-based base station receiver for wireless DS-CDMA with conjugate gradient (CG) adaptation in a multipath fading channel is studied. In order to construct a beamformer RAKE receiver, the existing code-filtering approach is used for each resolvable multipath component of the desired user, however, with another way to determine the optimum antenna weights. Thus, the desired user's signal is enhanced and the co-channel interference from other directions is reduced. The average uncoded bit error rate (BER) as a function of the average antenna signal-to-noise ratio (SNR) and the number of receiving antennas is examined in a frequency-selective Rayleigh fading channel. Simulation results show an increase in system capacity proportional to the number of antennas.