GLRT-Based Preamble Sequence Detection in OFDM

In practical orthogonal frequency division multiplexing standards, preamble waveforms are adopted to facilitate timing synchronization, frequency synchronization and system parameter acquisition. Due to implementation simplicity, the crosscorrelation-based method is adopted to determine the transmitted preamble sequence in the literature. However, because of the lack of channel estimation, the crosscorrelation-based method suffers severe performance degradation in large delay spread channels. To solve the problem, a preamble sequence detection method based on the generalized likelihood ratio test (GLRT) principle is proposed and analyzed in the paper. Due to embedded channel estimation, the GLRT method is shown to provide the decision error performance robust to channel dispersion and outperform the conventional crosscorrelation-based method significantly in large delay spread channels, at cost of increased implementation complexity.