# Generalized Fast-Convolution-based Filtered-OFDM: Techniques and Application to 5G New Radio

## TL;DR

This paper introduces a generalized fast-convolution method for waveform generation in 5G NR, enhancing spectral localization and interference suppression with improved efficiency over existing techniques.

## Contribution

It presents a novel generalized FC scheme combining overlapped processing and windowing, optimized for 5G NR subband filtering and interference reduction.

## Key findings

- Outperforms existing windowing methods in interference suppression
- Provides highly selective subband filtering with low intrinsic interference
- Offers flexible design parameters for different bandwidth parts

## Abstract

This paper proposes a generalized model and methods for fast-convolution (FC)-based waveform generation and processing with specific applications to fifth generation new radio (5G-NR). Following the progress of 5G-NR standardization in 3rd generation partnership project (3GPP), the main focus is on subband-filtered cyclic prefix (CP) orthogonal frequency-division multiplexing (OFDM) processing with specific emphasis on spectrally well localized transmitter processing. Subband filtering is able to suppress the interference leakage between adjacent subbands, thus supporting different numerologies for so-called bandwidth parts as well as asynchronous multiple access. The proposed generalized FC scheme effectively combines overlapped block processing with time- and frequency-domain windowing to provide highly selective subband filtering with very low intrinsic interference level. Jointly optimized multi-window designs with different allocation sizes and design parameters are compared in terms of interference levels and implementation complexity. The proposed methods are shown to clearly outperform the existing state-of-the-art windowing and filtering-based methods.