Performance Analysis of Transmit Diversity in WCDMA System

Abstract

In this paper, we focus on the transmit diversity technologies in WCDMA system. There are two schemes: open loop and closed loop transmit diversity simulated in this paper. We simulated with various conditions to consider the applicability of transmit diversity in WCDMA system. The simulation conditions contain different feedback delays, feedback error rates, and velocities of fading channel. We also propose two kinds of channel estimation mechanisms into the simulation: one incur little delay but inaccuracy, the other incur one frame time delay but is much more accurate. From the simulation results, we can know that in closed loop transmit diversity mode, the pilot symbol of DL DPCH seems not very helpful for channel estimation purpose. The CPICH will lead better performance for the system.