A new design of multi-path searcher in for W-CDMA mobile station with multi-antenna

In this paper, we present the performance analysis of a multi-path searcher operating over Rayleigh fading channels when multiple transmit antennas are employed in the downlink of the W-CDMA system. The simulation results for the receiver operating characteristics (ROC) for 2 and 4 transmit antennas are presented to corroborate the theoretical analysis. We also propose a procedure to find the optimum parameters for the double-dwell serial searcher, according to the number of multiple transmit antennas. Our analysis and simulations indicate that the post-detection integration technique is not necessary when the number of transmit antennas is more than two. Moreover, we found that increasing transmit diversity order does not necessarily improve the detection performance; rather it degrades the performance when the received pilot signal strength is relatively low. These findings give us practical criterion to increase transmit diversity order.