Robust time synchronization for NC-OFDM cognitive radio systems

Abstract

In this paper, we propose a time-synchronization method for non-contiguous orthogonal frequency division multiplexing (NC-OFDM) systems. NC-OFDM is a modulation and multiplexing technique that is often used for cognitive radio (CR) systems. In OFDM-based CR systems, time synchronization is limited by a number of challenges: multipath channels with a high delay spread, a narrowband interference (NBI), and minimal number of subcarriers. Indeed, the proposed method addresses these problems since it does not require information on subcarriers nor the NBI center frequency; moreover, it works well on the multipath channel with a high delay spread.