Downlink Synchronization and Initial Cell Search for 3GPP LTE System

• Main Authors: Yun-JhenFan, 范耘蓁
• Other Authors: Szu-Lin Su
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/36587665960991742683

碩士 === 國立成功大學 === 電腦與通信工程研究所 === 98 === In cellular communication systems the mobile station (MS) must perform initial synchronization and search for a base station to set up the downlink access. This process is the so-called initial cell search. To accomplish the operations mentioned above, two synchronization signals, the primary synchronization signal (PSS) and the secondary synchronization signal (SSS), are periodically transmitted from base station in the 3GPP LTE (Long Term Evolution) system. It is announced OFDM signal is applied to downlink transmission in the LTE cellular network. However, OFDM signal is sensitive to synchronization error, such as carrier frequency offset (CFO). CFO, which exists between the transmitter and the receiver, causes loss of orthogonality among subcarriers and inter-carrier interference (ICI) and degrade the system performance. In this thesis all the procedures of synchronization and initial cell search are specified. Two Innovative processing algorithms for PSS, including the theoretical analysis and deduction, are provided. Most important, the proposed schemes are able to evaluate the ICFO more accurately and improve the error rate effectively. Comparisons between the proposed schemes and the existing ones are illustrated in the simulation results. Furthermore, the proposed schemes also reduce the computational complexity.