Further Research on Quasi Complete Complementary Codes for Cell Search in Cell-Based OFDM Systems

• Main Authors: Kuei-Ying Lu, 呂奎穎
• Other Authors: Chi-chao Chao
• Format: Others
• Language: en_US
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/31929633315678693728

碩士 === 國立清華大學 === 通訊工程研究所 === 96 === 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 done with preamble sequences. Therefore, the performance of cell search depends greatly on the employed preamble sequences. 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, three preamble structures based on QCCCs are proposed in the thesis. Furthermore, the constructed QCCCs have low peak-to-average power ratios (PAPRs) and proposed in this thesis are hence suitable for use in orthogonal frequency division multiplexing (OFDM) systems. Efficient encoding and decoding algorithms are also proposed based on the rich algebraic structures of QCCCs. Compared with the computer-searched pseudo noise (PN) sequence preambles employed in the WiMAX system, great complexity reduction in encoding and detection can be obtain for QCCC-based preambles. Simulation results also show that for cell search the QCCC-based preambles perform as well as PN preambles.