Filtered OFDM Systems, Algorithms, and Performance Analysis for 5G and Beyond

Abstract

Abstract-Filtered orthogonal frequency division multiplexing (F-OFDM) system is a promising waveform for 5G and beyond to enable multi-service system and spectrum efficient network slicing. However, the performance for F-OFDM systems has not been systematically analyzed in literature. In this paper, we first establish a mathematical model for F-OFDM system and derive the conditions to achieve the interference-free one-tap channel equalization. In the practical cases (e.g., insufficient guard interval, asynchronous transmission, etc.), the analytical expressions for inter-symbol-interference (ISI), inter-carrier-interference (ICI) and adjacent-carrier-interference (ACI) are derived, where the last term is considered as one of the key factors for asynchronous transmissions. Based on the framework, an optimal power compensation matrix is derived to make all of the subcarriers having the same ergodic performance. Another key contribution of the paper is that we propose a multi-rate F-OFDM system to enable low complexity low cost communication scenarios such as narrow band Internet of Things (IoT), at the cost of generating intersubband-interference (ISubBI). Low computational complexity algorithms are proposed to cancel the ISubBI. The result shows that the derived analytical expressions match the simulation results, and the proposed ISubBI cancelation algorithms can significantly save the original F-OFDM complexity (up to 100 times) without significant performance loss.

Comparing f-OFDM and OFDM Performance for MIMO Systems Considering a 5G Scenario

“…As can be seen in Fig. 3, the f-OFDM modulation/demodulation process is very similar to that of the traditional OFDM technique, differing only in the addition of low-pass filters [8,9].…”

“…The appropriate filter design should maintain ICI (Inter Carrier Interference) and ISI (Inter Symbol interference) interference at acceptable levels [8].…”

A Spectrum Sharing Framework for Intelligent Next Generation Wireless Networks

“…One of the simplest but still very efficient approaches used to guarantee better spectral localization, i.e., lower out-ofband (OOB) emissions, and maintain the complex-domain orthogonality of the OFDM symbols is to apply some sort of filtering to the time domain OFDM symbols, giving rise to a new waveform known as Filtered-OFDM (f-OFDM) [56].…”

SINR‐based adaptive MIMO FBMC/OQAM transmission with automatic modulation classification

“…Aiming at a higher spectral efficiency compared to the well‐established cyclic prefix orthogonal frequency division multiplexing (CP‐OFDM) technique, a couple of new physical waveforms have been intensively studied in the last years . Most prominent examples that improve the poor side‐band suppression of CP‐OFDM and/or reduce the amount of redundancy by the cyclic prefix are filtered OFDM (f‐OFDM), universal‐filtered multicarrier modulation (UFMC), also named universal‐filtered OFDM, and generalized frequency division multiplexing (GFDM) . The problem of large out‐of‐band emission is alleviated in f‐OFDM using a transmit filter cascaded after the OFDM modulator.…”