Timing and frequency synchronization using ZCZ sequences for multi-cell OFDM systems

In this paper, we propose a complete solution using zero-correlation zone (ZCZ) sequences for timing and frequency synchronization in multi-cell orthogonal frequency-division multiplexing (OFDM) systems. The proposed scheme consists of the following operations: coarse timing synchronization, fractional carrier frequency offset (CFO) estimation and compensation, and joint integer CFO estimation and fine timing synchronization. The ZCZ sequences from the same family set are designed as the training symbols applied to adjacent cells. Due to the perfect autocorrelation and cross-correlation properties of the ZCZ sequences within a certain correlation zone, the inter-cell interference (ICI) of the training symbols can be effectively mitigated by utilizing a time-domain (TD) correlation based synchronization scheme. Simulation results show that the proposed synchronization scheme using ZCZ sequences can effectively mitigate the inter-cell interference and thus improve the synchronization accuracy especially when the mobile stations (MSs) are on the cell boundary.