| Summary: | 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.
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