Cell Search for Cell-Based OFDM Systems Using Quasi Complete Complementary Codes

• Main Authors: Ying-Ju Min, 閔瀅如
• Other Authors: Chi-chao Chao
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/46277927979017757334

碩士 === 國立清華大學 === 通訊工程研究所 === 95 === Establishing a radio link in cell-based mobile communication systems involves searching and synchronizing the downlink known pattern of sequences associated with the base stations. The searching process, often referred to as cell search, is usually completed by preamble sequences. Therefore, the performance of cell search depends greatly on the preamble se- quences. In this thesis, we propose a construction of quasi complete complementary codes (QCCCs) from Reed-Muller (RM) codes. Since the constructed QCCCs have good auto- correlation and cross-correlation properties, we employ them as preamble sequences and propose a preamble structure based on QCCCs. Furthermore, the constructed QCCCs have low peak-to-average power ratio (PAPR), and hence they are suitable for use in orthogonal frequency division multiplexing (OFDM) systems. We compare the cell search performance of using QCCCs as preambles with that of the worldwide interoperability for microwave access (WiMAX, also referred to as IEEE standard 802.16e) preambles. Simulation results show that there is minor or acceptable performance degradation with our QCCCs employed as preambles, while the rich algebraic structures of QCCCs potentially permit low-complexity encoding and decoding.