Signal processing techniques for cell-free massive MIMO

虽然5G蜂窝系统的部署将持续到下一个十年，但人们已经对其继任者6 G的基础技术产生了很大的兴趣。预计6 G将支持万物互联（IoE），其中每km^3超过100万台设备（地面和空中）将需要无处不在、可靠、低延迟的连接。为了实现6 G这一雄心勃勃的愿景，必须开发颠覆性的技术范式。为此，该项目将研究一种非常有前途的无线技术，称为无蜂窝大规模MIMO。这里的主要思想是部署非常规的大量接入点，这些接入点在地理上分布，以在相同的时间频率资源中相干地服务于许多用户。理论上，无小区大规模MIMO可以在用户之间提供统一的服务质量（相关文献中称为用户公平性的特征），更低的延迟和无处不在的连接。然而，将这一颠覆性的学术概念转化为商业现实是一项非常具有挑战性的工作，也正是这个博士项目的核心。特别是，学生将开发适用于无蜂窝大规模MIMO网络的新信号处理解决方案。特别感兴趣的是以下技术目标：（a）提出新的实用的以用户为中心的方法，其中每个用户由其选择的接入点子集服务;（B）开发可扩展的功率控制方案，以通过使用深度学习或机器学习来对抗固有的干扰问题;（c）采用新的先进信号处理技术，这些技术可以分散方式实施，并提供令人满意的性能。科学界花了近5年时间（2010-2014年）才认识到大规模MIMO的重要性，还需要5年时间（2015-2020年）才能使这项技术成熟并准备投入商业使用。展望未来，无蜂窝大规模MIMO将成为并行无线技术的自然演进。该项目将通过探索EPSRC的以下研究领域和跨ICT优先事项来最大限度地提高国家影响力（2017-2020年）：未来智能技术-无细胞大规模MIMO将为不同物体，机器和人类之间的低功耗，无处不在的通信开辟新的视野，完全符合EPSRC的愿景，即“促进旨在开发智能，自适应或自主系统的研究，这些系统可以学习，ICT网络和分布式系统-该项目提出的新技术将在5G+时代（2025年以后）实现超高速蜂窝通信。此外，该项目将通过降低无线网络的功耗来产生社会经济影响，从而为英国政府减少该国二氧化碳排放的系统性努力做出贡献。这项工作的未来商业开发将最终导致创造新的就业机会，初创公司使用无线技术开发新技术，从而为英国人口创造财富和更好的服务，并为未来的英国经济成功做出贡献，以保持其在这一领域的领先地位。由于无蜂窝大规模MIMO领域仍处于起步阶段，该项目还将对不同领域产生重大的学术影响：信号处理，信息理论，数据科学，优化，电子学，天线理论等等。因此，该项目的出版物可以成为参考文献，并最终导致将创造的知识纳入教育课程，这将进一步确立英国在最先进的知识转移方面的世界领先地位。所有研究结果将及时在一些相关的高影响因子期刊和顶级国际会议上发布

While the deployment of 5G cellular systems will continue well into the next decade, much interest is already being generated towards technologies that will underlie its successor, 6G. 6G is anticipated to support the Internet-of-Everything (IoE), where upwards of a million devices per km^3 (both terrestrial and aerial) will require ubiquitous, reliable, low-latency connectivity. To realise this ambitious vision of 6G, disruptive technological paradigms have to be developed.To this end, this project will be looking into a very promising wireless technology, coined as cell-free massive MIMO. The main idea here is to deploy an unconventionally large number of access points, that are geographically distributed, to coherently serve many users in the same time-frequency resources. Cell-free massive MIMO can theoretically offer uniform quality of services across users (a feature known as user fairness in the related literature), lower latency and ubiquitous connectivity. Yet, transforming this disruptive academic concept into a commercial reality is a very challenging exercise and is precisely the core of this PhD project.In particular, the student will be developing new signal processing solutions suitable for cell-free massive MIMO network. Of particular interest are the following technical objectives: (a) propose new practical user-centric approaches, wherein each user is served by its selected subsetof access points; (b) develop scalable power control schemes to combat the inherent interference problem by using deep learning or machine learning; (c) introduce new advanced signal processing techniques that can be implemented in a distributed manner and offer satisfactory performance.Vision and timeliness: The scientific community needed nearly 5 years to appreciate the importance of massive MIMO (2010-2014) and 5 more years were required (2015-2020) in order to make this technology mature and ready for commercial use. Looking ahead, cell-free massive MIMO emerges as the natural evolution of concurrent wireless technologies.This project will maximise national impact by exploring the following EPSRC's research areas and cross-ICT priorities (2017-2020):Future Intelligent Technologies - Cell-free massive MIMO will open new horizons for low-power, ubiquitous communication between different objects, machines and humans, fully aligned with the EPSRC vision to "promote research which aims to develop intelligent, adaptive or autonomous systems that can learn, adapt and make decisions without the need for human control''.ICT networks and distributed systems - The novel techniques proposed in this project will enable ultra-high speed cellular communications in the 5G+ era (2025 onwards). Moreover, the project will create socio-economic impact by reducing the power consumption of wireless networks, therefore contributing to the systematic efforts of the UK government to reduce the country's CO2 emissions. Future commercial exploitation of the work will eventually lead to the creation of new jobs, start-up companies developing new technologies using wireless technologies, thereby producing wealth and better services for the UK population and contribute to future UK economic success in order to maintain its leading position in this area of endeavour.Since the area of cell-free massive MIMO is still in its infancy, the project will also have substantial academic impact on diverse fields: signal processing, information theory, data sciences, optimisation, electronics, antenna theory to name but a few. Accordingly, the project's publications could become reference literature and eventually lead to the inclusion of the created knowledge in the educational curricula will further establish the UK as a world leader in state-of-the-art knowledge transfer. All research findings will be prepared for timely dissemination in a number of relevant high impact factor journals and at top international conference