Channel Estimation Approach with Low Pilot Overhead in FBMC/OQAM Systems

Jun Sun,Qian Wang,Xiaomin Mu,Dejin Kong,Xing Cheng,Xinmin Li,Liangtian Wan

doi:10.1155/2021/5533399

Abstract

In filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) systems, a large pilot overhead is required due to the existence of the imaginary interference. In this paper, we present an approach to reduce the pilot overhead of channel estimation. A part of pilot overhead is used for transmitting data, and compensating symbols are required and designed to remove the imaginary interference. It is worthwhile to point out that the power of compensating symbols can be helpful for data recovery; hence, the proposed approach decreases the overhead of pilots significantly without the cost of additional pilot energy. In addition, the proposed scheme is extended into multiple input multiple output systems without the performance loss. Compared with the conventional preamble consisting of 3 columns symbols, the pilot overhead is equivalent to 2 column symbols in the proposed preamble. To verify the proposed preamble, numerical simulations are carried out with respects to bit error ratio.

Highlights

Filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) has been considered as a potential alternative [1,2,3,4] to the conventional orthogonal frequency division multiplexing (OFDM)
In the absence of the channel, intersymbol interference (ISI) appears as an imaginary component that adds to the real-valued data symbols which are carried by the FBMC/OQAM waveform, which has to be considered in the pilot design
We present an approach to reduce the pilot overhead of channel estimation in FBMC/OQAM systems

Summary

Introduction

Filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) has been considered as a potential alternative [1,2,3,4] to the conventional orthogonal frequency division multiplexing (OFDM). The imaginary interference has a crucial effect on the pilot design. While in OFDM receiver data/pilot symbols that are perfectly separated after applying the FFT, the signal samples from the output of the analysis filter in an FBMC/OQAM receiver are subject to intersymbol interference (ISI), both along the time and frequency/subcarriers. In the absence of the channel, ISI appears as an imaginary component that adds to the real-valued data symbols which are carried by the FBMC/OQAM waveform, which has to be considered in the pilot design

Methods

Results

Conclusion