Smart services based on Internet of everything (IoE) are prophesied to reap notable attention by both academia and industry in the future. Although fifth-generation (5G) is a promising communication technology, however it cannot fulfill complete demands of novel applications. Sixth-generation (6G) technology is envisaged to overcome limitations of 5G technology. The vision and planning of future 6G network has been started with this aim to meet the stringent requirements of mobile communication. Our aim is to explore recent advances and potential challenges to enable 6G technology in this review. We have devised a taxonomy based on computing technologies, networking technologies, communication technologies, use cases, machine learning algorithms and key enabler technologies. In this regard, we subsequently highlight potential features and key areas of 6G. Key technological breakthroughs which include quantum communication, tactile communication, holographic communication, terahertz communication, visible light communication (VLC) Internet of Bio Nano Things, which can put profound impact on wireless communication, have been elaborated at length in this review. In this review, our prime focus is to discuss potential enabling technologies which can develop seamless and sustainable network, encompassing symbiotic radio, blockchain, new communication paradigm, VLC and terahertz. In addition, we have investigated open research challenges which can hamper the performance of 6G network. Finally, we have outlined several practical considerations, 6G key projects and future directions. We envision 6G undergoing unprecedented breakthroughs to eliminate technical uncertainties and provide enlightening research directions for subsequent future studies. Although it is impossible to envisage complete details of 6G, we believe this study will pave the way for future research work.

翻译：基于万物互联（IoE）的智能服务预计将在未来引起学术界和工业界的显著关注。尽管第五代（5G）通信技术前景广阔，但无法完全满足新型应用的需求。第六代（6G）技术旨在克服5G技术的局限性。未来6G网络的愿景与规划已围绕满足移动通信的严苛需求而展开。本综述旨在探索实现6G技术的最新进展与潜在挑战。我们构建了基于计算技术、网络技术、通信技术、用例、机器学习算法及关键使能技术的分类体系。在此基础上，进一步强调了6G的潜在特性与核心领域。本综述详细阐述了可能对无线通信产生深远影响的关键技术突破，包括量子通信、触觉通信、全息通信、太赫兹通信、可见光通信（VLC）及生物纳米物联网。本综述重点关注如何构建无缝且可持续网络的潜在使能技术，涵盖共生无线电、区块链、新型通信范式、VLC与太赫兹技术。此外，我们探讨了可能制约6G网络性能的开放研究挑战。最后，概述了多项实际考量、6G关键项目及未来方向。我们预测6G将经历前所未有的突破，以消除技术不确定性，并为后续研究提供启发性的研究方向。尽管无法预见6G的全部细节，但相信本研究将为未来科研工作铺平道路。