Design and VLSI implementation for a WCDMA multipath searcher
AbsfmctUnlike in the IS-95 based synchronous CDMA system, in the 3GPP’s asynchronous WCDMA system, it is impossible for the network to estimate the round trip delay between the handover UE and the target base station before the handover execution, so the uplink handover search window size of the target BS becomes large. In order to get the good link quality during handover execution, it is very important to reduce the uplink handover search time at the target BS. In this paper, we propose an efficient uplink handover search scheme for asynchronous WCDMA system. Average search time performance of proposed scheme is analyzed for fading channel environment. The effects of non-coherent accumulation length of search mode and that of verification mode to the average search time performance are analyzed. And the optimal threshold values of search mode and verification mode are investigated. The results analyzed in this paper may be useful for designing the uplink handover searcher of 3GPP’s WCDMA base station.