Low Complex, Narrowband-Interference Robust Synchronization for NC-OFDM Cognitive Radio

Abstract

This paper presents a new, low-complexity algorithm for time and frequency synchronization in a Non-ContiguousOrthogonal Frequency Division Multiplexing (NC-OFDM) radio communication system in the presence of narrowband interference (NBI). This interference scenario is plausible for Cognitive Radio (CR) systems. The computational complexity of the proposed synchronization method is similar to the known Schmidl&Cox algorithm. The algorithm is partially blind, i.e., it does not require information on the NC-OFDM subcarriers used, nor on the center-frequency of the NBI. Moreover, it does not require filtering to remove the NBI. It performs best for the NBI of constant carrier frequency, but it also provides good results for the frequency-modulated (FM) interfering signal.