Investigation, Simplification and Designs of Cell Search Algorithms based on BPSK-Modulated Synchronization signals

• Main Authors: Wang, Yi-Shen, 王奕翔
• Other Authors: Chen, Sau-Gee
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/68287497532417431049

碩士 === 國立交通大學 === 電子研究所 === 99 === To ensure good transmission quality, a mobile user has to establish connection with a base station before transmitting or receiving any data. Cell search is the procedure that helps a user identify the nearest base station, and then a number of steps will be taken to enter the network via the base station. However, searching all possible base stations to find the nearest one requires high computation complexity as well as the execution time. This thesis focuses on low complexity designs of cell search based on BPSK-modulated signals. There have been a lot of techniques focusing on the same topic as this thesis. Most of them reduce the computation complexity at the price of performance loss. In this thesis, several low-complexity techniques for cell search without performance loss are proposed. The Grouping method and the Level-shifted method are the most important methods among all the proposed methods. In the Grouping method, an efficient multiplexing scheme is derived to achieve low-complexity realizations of the existing cell search methods. In the Level-shifted method, a new metric for cell search is derived by employing the binary characteristic of BPSK-modulated synchronization signals. The effect of timing offset on cell search is also investigated in this thesis. When timing errors exist, the conventional cell search algorithm is robust to timing errors and no performance loss results. If the symbol timing can be acquired to reasonable accuracy, the conventional cell search method can be further simplified.