Experimental Evaluation of Three-Step Cell Search Method in W-CDMA Mobile Communications

Kenichi HIGUCHI  Yukiko HANADA  Mamoru SAWAHASHI  Fumiyuki ADACHI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E85-A   No.7   pp.1511-1523
Publication Date: 2002/07/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Multi-dimensional Mobile Information Networks)
DS-CDMA,  asynchronous cell site,  cell search,  code acquisition,  scrambling code,  

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This paper investigates the cell search time performance of our previously proposed three-step cell search method in a two-cell site environment by laboratory and field experiments supporting asynchronous cell site operation, which is one of the most notable features of wideband direct sequence code division multiple access (W-CDMA) mobile communications. The cell search methods used in the paper are based on the ongoing third generation partnership project (3GPP), in which our original scheme was refined with respect to several points in order to reduce the complexity of the receiver. The experimental results demonstrate that the method achieves the fast cell search time of less than one second in real multipath-fading channels. The cell search is accomplished in less than approximately 700 msec at 90% of the detection probability when 4.7% and 0.5% of the total transmit power of a cell site is assigned to the common pilot channel (CPICH) and synchronization channels (SCHs), respectively, in a two-cell site environment. We also elucidate that the cell search time at the detection probability of 90% using time switched transmit diversity (TSTD) is decreased by approximately 100 msec compared to that without TSTD in low-mobility environments such as the average vehicular speed of 5 km/h with a transmit power assignment of the CPICH of 4.7%.