A new synchronization algorithm for OFDM systems in multipath environment

摘要

Carrier frequency and symbol timing errors may greatly degrade the performance of the orthogonal frequency division multiplexing (OFDM) system, especially in multipath environment. We explore the cyclostationarity of OFDM signals, which only relies on second order statistics, to estimate the synchronization offset. First, a coarse carrier frequency offset estimator for multipath environment is developed using the second order statistics of the received OFDM signal. It has a wide capture range though not accurate. Second, we introduce a new synchronization algorithm based on cyclostationarity and matched filter theories, which can get the maximal estimation SNR in multipath environment. Both estimators utilize channel state information to achieve better estimation performance and are non-pilot aided. They can be combined to form a whole OFDM synchronizer in multipath environment. Finally, simulations confirm the performance of the estimation algorithm.