Experiments on Fast Cell Search Algorithm Using Scrambling Code Masking for Inter-Cell Asynchronous W-CDMA System

This paper presents the fast cell search time performance based on laboratory and field experiments of a 2step cell search algorithm that uses scrambling code masking for inter-cell asynchronous wideband DS-CDMA (W-CDMA) mobile radio. The scrambling code is masked at different time positions during each scrambling period on the forward-link common control channel (CCH) to detect the scrambling code timing at the mobile receiver. Experiments were conducted using the CCHto-dedicated traffic channel (DTCH) power ratio, R of 3 dB, 10 DTCHs, and 10 scrambling codes in a single-cell and two-cell models. The field experimental results show that the cell search time of about 600 msec was achieved in vehicular environments at the detection probability of 90% and the average received E^/No (No is the background noise without interference) of 13-15 dB for DTCH, even in the worst case scenario when the received signal power ratios of the CCH from two cell sites were 0 dB. The cell search time that was achieved with the 3-step cell search algorithm previously proposed by the authors is estimated from the experimental results; the cell search can be accomplished within about 720 msec at a probability of 96% for 512 scrambling codes and 16 scrambling code groups.