A Novel Frame Synchronization Method Using Correlation Between Permuted Sequences

A novel "permuted sequences combination" method is proposed in this paper, which uses the conventional frame structure wherein two sync words, each comprising M complex symbols, are appended at the frame start. The goal of this new method is to reduce the large variance of the timing estimation error inherent in the conventional correlation method. Essentially, the first sync word, stilde
₁
, is a predetermined constant amplitude zero autocorrelation (CAZAC) sequence. The second sync word, stilde
₂
, which is a certain permutation of the first so that the combination of the two received sync signal vectors perform sliding window processing with peak occurs at the correct frame start. We show that the symmetric correlation method previously presented in (Park et al., 2003) for orthogonal frequency division multiplexing (OFDM) systems can be regarded a special case of the proposed permuted sequences combination method. As a special case of permuted sequences combination method, symmetric correlation method is robust to the frequency offset. The proposed methods have good simulation results in both AWGN channel and multipath environments. Simulation results support the analysis.