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

TL;DR

This paper introduces a low-complexity, partially blind synchronization algorithm for NC-OFDM systems that is robust against narrowband interference, suitable for cognitive radio applications.

Contribution

It proposes a novel synchronization method that does not require prior knowledge of subcarriers or interference center-frequency, with complexity similar to existing algorithms.

Findings

Performs well with constant carrier frequency NBI

Provides good results with frequency-modulated interference

Does not require filtering or interference information

Abstract

This paper presents a new, low-complexity algorithm for time and frequency synchronization in a non-contiguous-orthogonal frequency division multiplexing (NC-OFDM) radio communication system in the presence of narrowband interference (NBI). This interference scenario is plausible for cognitive radio 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 interfering signal.