Research And Implementation Of Wcdma Cell Search Algorithms

In a CDMA cellular system, the process of the mobile station searching for a cell and achieving time synchronization to its downlink scrambling code is referred to as cell search. As one of the most competitive standards for the third generation mobile communication in the world,WCDMA system has a unique cell search which can be divided into five acquisition stages: slot synchronization, frame synchronization and scrambling code group identification, scrambling code identification, frequency acquisition, and cell identification. This paper mainly focuses on the research and implementation of WCDMA cell search algorithms.This paper is divided into five parts. The first part introduces WCDMA mobile communication standards, its history and main features.The second part details the physical layer of WCDMA FDD mode, including channel classification, concepts such as spreading, scrambling and modulation, so that we can have a clear understanding of WCDMA physical layer.The third part firstly describes the basic principles of WCDMA initial cell search. Subsequently, it focuses on the study related to cell search, such as time slot synchronization, frame synchronization and code group identification, scrambling code identification and frequency estimation. According to theoretical analysis and matlab simulation, the performance of corresponding algorithms is derived and analyzed in different propagation environments, different signal to noise ratio and different system frequency offset. After that, a specific implementation scheme is carried out conclusively.The principle of WCDMA RAKE receiver is analyzed in the fourth part, some of the key technologies, such as channel estimation, multipath searching and so on are further studied. Finally, to meet the needs of pratical WCDMA scanner system, specific methods carried out for RAKE receiver modules implemented in the DSP are discussed.Upon completion of the three step cell search, the standards of 3GPP RRC layer is studied. Performance of reception on system information, reassembly and parsing of system information is analyzed in details and carried out afterwards.