A blind synchronizer for OFDM systems based on SINR maximization in multipath fading channels

This paper presents a blind synchronizer for orthogonal frequency-division multiplexing (OFDM) systems based on signal-to-interference-and-noise ratio (SINR) maximization. Due to the incurred losses from intersymbol interference (ISI) and intercarrier interference (ICI) introduced by synchronization errors, the SINR of the received data drastically drops. By taking advantage of this characteristic, both the symbol time and carrier frequency offsets are intuitively estimated by maximizing the SINR metric. For the SINR metric, two blind SINR estimations are investigated. The estimations do not need prior knowledge of the channel profiles and transmitted data. As such, the proposed maximum SINR (MSINR) synchronization algorithm is nondata aided so that the transmission efficiency can be improved. Moreover, to reduce the computational complexity, the early-late gate technique is proposed for the implementation of the synchronizer. Simulation results exhibit better performance for the MSINR algorithm than conventional techniques in multipath fading channels. Index Terms--Blind synchronization, early-late gate (ELG), orthogonal frequency-division multiplexing (OFDM), signal-to-interference-and-noise-ratio (SINR) maximization.