Performance of chip-/symbol-level beamforming algorithm for WCDMA-TDD system

We present a chip level adaptive beamforming algorithm for a TDD-based WCDMA system in a Rayleigh fading channel (NLOS), and analyze its performance through computer simulation. The proposed chip level beamforming (CLB) algorithm is conducted at chip rate before despreading of the received signal while an existing symbol level beamforming (SLB) is conducted at symbol rate after despreading. We define DOA (direction of arrival) error and SG (suppressing gain) as a criterion of performance measure to compare the relative uplink performance of the CLB-based receiver with the SLB-based receiver. The performance is analyzed by comparing BER, DOA errors and SG in the modified Jakes model according to the number of users. The simulation result shows that the performance of the CLB-based receiver is superior to that of the SLB-based receiver with respect to BER and SG, but it is inferior in DOA error in a realistic mobility channel.