Over the past few decades, wireless communication has witnessed remarkable growth, experiencing several transformative changes. This article aims to provide a comprehensive overview of wireless communication technologies, from the foundations to the recent wireless advances. Specifically, we take a neutral look at the state-of-the-art technologies for 5G and the ongoing evolutions towards 6G, reviewing the recommendations of the International Mobile Communication vision for 2030 (IMT-2030). We first highlight specific features of IMT 2030, including three IMT-2020 extensions (URLLC+, eMBB+, and mMTC+) and three new innovations (Ubiquitous connectivity and integrating the new capabilities of sensing & AI with communication functionality). Then, we delve into three major challenges in implementing 6G, along with global standardization efforts. Besides, a proof of concept is provided by demonstrating terahertz (THz) signal transmission using Orbital Angular Momentum (OAM) multiplexing, which is one of the potential candidates for 6G and beyond. To inspire further potential research, we conclude by identifying research opportunities and future visions on IMT-2030 recommendations.

翻译：过去几十年间，无线通信经历了显著增长与数次变革性突破。本文旨在全面概述从基础理论到近期前沿进展的无线通信技术。具体而言，我们以中立视角审视5G现有技术及向6G演进的持续发展，梳理了国际移动通信2030年愿景（IMT-2030）的建议。首先，我们重点阐述IMT-2030的特定特征，包括三大IMT-2020扩展（URLLC+、eMBB+与mMTC+）及三大创新（泛在连接、感知与AI新能力与通信功能的融合）。随后，深入探讨实施6G面临的三大挑战及全球标准化进程。此外，通过演示基于轨道角动量（OAM）复用的太赫兹（THz）信号传输概念验证——该技术是6G及未来通信的潜在候选方案之一。为激发进一步研究，最后我们总结IMT-2030建议下的研究机遇与未来愿景。