Emerging applications such as Internet of Everything, Holographic Telepresence, collaborative robots, and space and deep-sea tourism are already highlighting the limitations of existing fifth-generation (5G) mobile networks. These limitations are in terms of data-rate, latency, reliability, availability, processing, connection density and global coverage, spanning over ground, underwater and space. The sixth-generation (6G) of mobile networks are expected to burgeon in the coming decade to address these limitations. The development of 6G vision, applications, technologies and standards has already become a popular research theme in academia and the industry. In this paper, we provide a comprehensive survey of the current developments towards 6G. We highlight the societal and technological trends that initiate the drive towards 6G. Emerging applications to realize the demands raised by 6G driving trends are discussed subsequently. We also elaborate the requirements that are necessary to realize the 6G applications. Then we present the key enabling technologies in detail. We also outline current research projects and activities including standardization efforts towards the development of 6G. Finally, we summarize lessons learned from state-of-the-art research and discuss technical challenges that would shed a new light on future research directions towards 6G.

中文翻译：

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6G前沿调查：趋势，应用，需求，技术和未来研究

诸如物联网，全息网真，协作机器人以及太空和深海旅游之类的新兴应用已经在凸显现有第五代（5G）移动网络的局限性。这些限制是在跨越地面，水下和太空的数据速率，延迟，可靠性，可用性，处理，连接密度和全球覆盖范围方面。第六代移动网络（6G）有望在未来十年中崭露头角，以解决这些局限性。6G愿景，应用，技术和标准的发展已经成为学术界和业界的热门研究主题。在本文中，我们对6G的当前发展进行了全面的调查。我们重点介绍了引发6G驱动的社会和技术趋势。随后将讨论新兴应用，以实现6G驱动趋势提出的需求。我们还阐述了实现6G应用所需的要求。然后，我们详细介绍了关键的启用技术。我们还概述了当前的研究项目和活动，包括针对6G发展的标准化工作。最后，我们总结了从最新研究中汲取的经验教训，并讨论了技术挑战，这些技术挑战将为6G的未来研究方向提供新的思路。我们还概述了当前的研究项目和活动，包括针对6G发展的标准化工作。最后，我们总结了从最新研究中汲取的经验教训，并讨论了技术挑战，这些技术挑战将为6G的未来研究方向提供新的思路。我们还概述了当前的研究项目和活动，包括针对6G发展的标准化工作。最后，我们总结了从最新研究中汲取的经验教训，并讨论了技术挑战，这些技术挑战将为6G的未来研究方向提供新的思路。