A Novel RAPF Algorithm and Its PAPR Reduction Performance Based DFT Spreading in FBMC-OQAM System

Compared with the orthogonal frequency division multiplexing (OFDM) system, filter bank multi-carrier (FBMC) with offset quadrature amplitude modulation (OQAM) system has a very different time-domain signal structure: owing to the use of identical prototype filter, the data symbols of adjacent blocks overlap each other in FBMC-OQAM system. Therefore, it is not effective that we directly apply discrete Fourier transform (DFT) spreading technique of OFDM system to FBMC-OQAM system. In this letter, we consider that the different prototype filters have distinct phase-frequency characteristics and the filter structure of FMBC-OQAM system can be selected flexibly, a randomly assigning prototype filters (RAPF) based DFT spreading technique is proposed for the peak-to-average power (PAPR) reduction in FBMC-OQAM system. Theoretical analyses and simulation results indicate that the proposed RAPF technique can effectively reduce PAPR in FBMC-OQAM system without increasing computational complexity.

I. Introduction

Orthogonal frequency division multiplexing (OFDM) has been applied in Long Term evolution (LTE). However, with the scarcity of spectrum resources and the diversified demand of communication scenarios, OFDM system gradually shows its shortcomings [1]. Therefore, it is necessary to research a new multi-carrier technology to meet the demand of the varied communication applications. FBMC-OQAM technology, through the design of the prototype filter, has been extensively studied recently. The FBMC-OQAM system offers many benefits such as low out-of-band radiation, high spectral efficiency, preeminent frequency localization and flexible bandwidth compared with the OFDM system [2]. Therefore, it is seen as an interesting alternative to OFDM for the next generation mobile communication.