Filtered OFDM: an insight into intrinsic in-band interference and filter frequency response selectivity

Mao, J., Zhang, L. , Xiao, P. and Nikitopoulos, K. (2020) Filtered OFDM: an insight into intrinsic in-band interference and filter frequency response selectivity. IEEE Access, 8, pp. 100670-100683. (doi: 10.1109/ACCESS.2020.2997316)

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The future mobile networks will face challenges in support of heterogeneous services over a unified physical layer, calling for a waveform with good frequency localization. Filtered orthogonal frequency division multiplexing (f-OFDM), as a representative subband filtered waveform, can be employed to improve the spectrum localization of orthogonal frequency-division multiplexing (OFDM) signal. However, the applied filtering operations will impact the performance in various aspects, especially for narrow subband cases. Unlike existing studies which mainly focus its benefits, this paper investigates two negative consequences inflicted on single subband f-OFDM systems: in-band interference and filter frequency response (FFR) selectivity. The exact-form expression for the in-band interference is derived, and the effect of FFR selectivity is analyzed for both single antenna and multiple antenna cases. The in-band interference-free and nearly-free conditions for f-OFDM systems are studied. A low-complexity blockwise parallel interference cancellation (BwPIC) algorithm and a pre-equalizer are proposed to tackle the two issues caused by the filtering operations, respectively. Numerical results show that narrower subbands suffer more performance degradation compared to wider bands. In addition, the proposed BwPIC algorithm effectively suppresses interference, and pre-equalized f-OFDM (pf-OFDM) considerably outperforms f- OFDM in both single antenna and multi-antenna systems.

Item Type:Articles
Additional Information:This work was supported by the U.K. Engineering and Physical Sciences Research Council under Grant EP/R001588/1. The authors would like to acknowledge the support of the University of Surrey 5GIC ( members for this work.
Glasgow Author(s) Enlighten ID:Zhang, Professor Lei
Authors: Mao, J., Zhang, L., Xiao, P., and Nikitopoulos, K.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:IEEE Access
ISSN (Online):2169-3536
Published Online:25 May 2020
Copyright Holders:Copyright © 2020 The Authors
First Published:First published in IEEE Access 8: 100670-100683
Publisher Policy:Reproduced under a Creative Commons License

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