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 laborato ry and field experiments of a 2-step cell search algorithm that uses scramb ling code masking for inter-cell asynchronous wideband DS-CDMA (W-CDMA) mob ile 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 CCH to-dedicated traffic channel (DTCH) power ratio, R of 3 dB, 10 DTCHs, and 16 scrambling codes in a single-cell and two-cell m odels. The field experimental results show that the cell search time of abo ut 600 msec was achieved in vehicular environments at the detection probabi lity of 90% and the average received E-b/N-0 (N-0 is the background noise w ithout 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 alg orithm previously proposed by the authors is estimated from the experimenta l results; the cell search can be accomplished within about 720 msec at a p robability of 96% for 512 scrambling codes and 16 scrambling code groups.