Pseudo-Noise Sequence Based Synchronization for Generalized Frequency Division Multiplexing in 5G Communication System

Abstract

As one of the candidate waveforms for 5G, generalized frequency division multiplexing (GFDM) is a flexible non-orthogonal multicarrier technique. Similar to orthogonal frequency division multiplexing, GFDM communication system suffers from symbol timing offset (STO) and carrier frequency offset (CFO) caused by multipath effect and Doppler shift. In this paper, we design a pseudo noise (PN) based preamble and propose an approach for signal synchronization. The preamble is composed of two identical PN sequences whose autocorrelation and cross-correlation are better than cyclic prefix (CP). STO can be detected by calculating the correlation coefficient between the local PN sequence of receiver and the corresponding preamble part of sliding window. These two adjacent PN sequences can be used to calculate phase offset value by Fourier transform, and then obtain CFO value. Simulation results demonstrate that, compared with conventional CP-based synchronization, the proposed approach has the lower mean square error and symbol error rate at the cost of just a little bit more bandwidth.

Keywords

• 5G
• GFDM
• non-orthogonal multicarrier
• synchronization
• OFDM