Novel Code Filter-Bank Multicarrier Scheme with Low Complexity for OQAM Symbol Transmission and Reception

Filter bank multicarrier with offset quadrature amplitude modulation (FBMC-OQAM) system has low out-of-band emission but needs complex receiver for broadband channel. To address this problem, we propose a new cyclic prefix (CP)-based code FBMC-OQAM system (CC-FBMC-OQAM) with low complexity in this paper. CC-FBMC-OQAM system can be realized within the framework of the standard OFDM system, and perfect recovery (PR) condition is derived in the ideal channel. In order to reduce compute complexity, a low complexity transform of the Fast Walsh-Hadamard and Fourier transform (FWFT) is adopted and it uses a fast orthonormal unitary transform to calculate both the discrete Fourier transform (DFT) and the Walsh-Hadamard transform (WHT). Theoretical analysis and simulation results show that, compared to the C-FBMC-OQAM system and orthogonal frequency division multiplexing (OFDM) system, the computational complexity of proposed CC-FBMC-OQAM system is reduced substantially with almost same bit error rate (BER) performance in doubly-flat channel. Moreover, the BER performance of proposed CC-FBMC-OQAM system slightly outperform conventional C-FBMC-OQAM system in doubly-selective channel.

I. Introduction

Orthogonal frequency division multiplexing (OFDM) have been widely applied to broadband multicarrier communications, which is able to avoid inter-symbol interference (ISI) by inserting a suitable cyclic prefix (CP). However, the OFDM system uses rectangular pulse shaping on each sub-channel, which leads to high out-of-band emission [1]. To remedy this problem of OFDM system, many researchers are exploring alternative waveforms for the fifth generation of wireless communications (5G) [2].