Analysis of Cell Search Performance for W-CDMA Cellular System

摘要

Wideband DS-CDMA (W-CDMA) has been used as the wireless access system for the IMT-2000 next-generation mobile communications system. Since this is an asynchronous inter-base-station system, spreading code (scrambling code) identification and timing synchronization detection must be performed during cell search. A three-step cell search method has been proposed for this purpose. In each step, the average value of the instantaneous received signal over a certain period (after despreading) is used for identification. Thus, the accuracy of identification is strongly dependent on the averaging period. This paper analyzes the basic relationship between the averaging period and identification accuracy, taking account of the SIR, the maximum Doppler frequency, and the number of samples used in averaging. The cell search characteristics are investigated for each step of the three-step cell search method.