Estimations of time error and frequency offset upon initial synchronization are investigated in this paper as components of the sector search process in third-generation partnership project (3GPP) long-term evolution (LTE) communications. The proposed system considers intercell interference, inter-carrier interference and multipath fading by exploiting various diversity. A coarse timing alignment is achieved by the acquisition of a primary synchronization sequence. The coarse timing alignment extracts autocorrelation at a long lag of one half of a frame length from the decimated signal at a lower sampling rate by exploiting a differential correlator.
Estimations of residual time error and fractional frequency offset are achieved by evaluating the short-lag autocorrelation at an OFDM symbol duration. The estimations utilize 70 cyclic prefixes that are pre-stored in the buffer employed in the aforementioned differential correlator. The estimations can effectively overcome the time variation of the channel that occurs as a result of a Doppler spread. Comprehensive computer simulations are conducted to verify that the proposed technique can effectively overcome inter-cell interference, time-selectivity, and multipath fading, thereby achieving low estimation errors.