Performance Enhancements to the WCDMA Cell Search Algorithms

In this paper, we study the various steps involved in the cell search process and an attempt has made to simulate them. When the received signal was correlated with the Primary Synchronization Code (PSC) sequences generated at the mobile station (MS), some peak values were obtained and the maximum of those peak values was displayed as the slot value for that particular frame. In frame synchronization process, a Fast Hadamard Transformer (FHT) was used to match arbitrary Secondary Synchronization Code (SSC) sequence with the frames and 16 values were obtained. In code synchronization process, the 16 values obtained are match with the values generated at the MS and the max of those values will be taken. The simulations designed satisfy most of the requirements of the parameters mentioned in the 3GPP specifications. The purpose of the cell search algorithm in UMTS is to estimate the spreading code of the serving base-station and its corresponding timing offset. The search procedure consists of 3 sequential and distinct stages: (1) slot-boundary synchronization, (2) frame-boundary synchronization with code-group identification, and (3) scrambling code identification. Algorithms that have appeared for cell search have confined the “code-time” estimation in each stage to a single hypothesis. In this paper, we also study the performance benefits of estimating multiple “code-time” hypotheses in each stage of the cell-search process. The main objectives of this paper is to construct a model using MATLAB to illustrate the working of the various processes involved in cell search and to analyze the difference between the results of system model. Keyword: WCDMA, UMT, SSC, PSC, FHT, CSD,PFA, VTH