Towards 100 Gigabit Wireless Networking by Light (Go-by-Light) (Ext.)

这是“解决无线通信中迫在眉睫的频谱危机”研究项目的延伸。未来的经济成功不可避免地与数字技术的进步联系在一起。数字技术组合的一个重要组成部分是数字通信，这也反映在EPSRC的“互联国家”交付计划中。无线网络是实现“连接”的基础。根据思科白皮书（“思科可视化网络指数：全球移动数据流量预测更新，2016-2021，白皮书”，2017年2月9日），仅在过去5年，移动数据流量就增长了18倍。这相当于78%的复合年增长率（CAGR），预计在2016年至2021年间将进一步增长7倍，到2021年将达到每月49.0艾字节。这种增长是由智能手机上新的无线服务推动的，比如增强现实和虚拟现实以及移动电视。此外，新的网络模式，如物联网或更普遍的机器类型通信将变得越来越重要，特别是支持自主系统的运行。这意味着，假设全球移动数据流量的平均复合年增长率为60%，从现在开始的20年内，分配给当前射频系统的500 MHz射频（RF）信道在2037年将需要6太赫兹的带宽。目前用于无线通信的整个射频频谱仅为0.3太赫兹。LiFi在射频频谱中增加了毫米波红外和可见光频谱，总带宽为780太赫兹。这种不受管制的频谱有可能使无线通信经得起未来的考验。虽然目前的研究项目在使用发光二极管（led）实现数据速率方面取得了突破性的进展，如最近展示的单个设备的15 Gbps数据速率，但需要进一步的大量研究工作来释放整个红外和可见光光谱的全部潜力，并使LiFi成为无线通信结构的一个组成部分。此外，迄今为止的研究主要集中在提高静态发送器和接收器布置中的链路级性能。为了实现一个完全由光连接的世界的愿景，汽车前灯、路灯、办公室、工厂和家庭的灯，包括电脑屏幕和家用电器的指示灯，形成未来的无线网络，需要进行基础研究，以确保终端在移动时保持连接，并有效减轻大量同时传输时产生的干扰。或者随机阻塞不会导致链路故障。最后，随着LiFi接入点的大量增加，还存在许多挑战。具体来说，许多接入点必须通过合适的回程连接连接到网络骨干。LiFi系统由激光发射器和太阳能电池组成，作为数据接收器，被认为是回程挑战的关键。正是后一种考虑也将有助于消除目前阻碍世界60%人口获得数字通信的农村鸿沟。对于这些基本问题，目前还没有可行的解决办法，这就是延长研究金的作用所在，它将目前的国际领先成就提升到一个新的水平。LiFi现在处于20年前WiFi的阶段，未来几年的工作将是使这项技术取得成功的关键。

This is an extension of the Fellowship: 'Tackling the looming spectrum crisis in Wireless Communication'. Future economic success is inevitably tied to advancements in digital technologies. An essential component in the mix of digital technologies is digital communications, as also reflected in the EPSRC delivery plan under the heading of 'Connected Nation'. Wireless networking is fundamental to the achievement of 'connectivity'. According to a Cisco White Paper ("Cisco Visual Networking Index: Global Mobile Data Traffic Forecast Update, 2016-2021, White Paper", February 09, 2017), mobile data traffic has increased 18 times in the last 5 years alone. This corresponds to a compound annual growth rate (CAGR) of 78% with a further sevenfold increase expected between 2016 and 2021, reaching 49.0 exabytes per month by 2021. This growth is fueled by new wireless services on smartphones such as augmented and virtual reality and mobile TV. In addition, new networking paradigms such as the Internet of Things or more generally machine type communication will become increasingly important, especially to support operation of autonomous systems. This means that by assuming an average CAGR of 60% of global mobile data traffic, in 20 years from now a 500 MHz radio frequency (RF) channel allocated to a current RF system would need a bandwidth of 6 THz in 2037. The entire RF spectrum, which is currently used for wireless communications, only amounts to 0.3 THz. LiFi adds to the RF spectrum the nm-wave infrared and visible light spectrum with a combined bandwidth of 780 THz. This unregulated spectrum has the potential to make wireless communications future-proof. While the current Fellowship enabled ground-breaking research on achievable data rates using light emitting diodes (LEDs) - as the recently demonstrated 15 Gbps data rates from a single device - further substantial research efforts are required to unlock the full potential of the entire infrared and visible light spectrum, and to make LiFi an integral part of the fabric of wireless communications. Furthermore, research to date has primarily focused on advancing link level performance in static transmitter and receiver arrangements. In order to realise the vision of a world fully connected by light where car headlights, street lights, lights in offices, factories and homes including computer screens and indicator lights of home appliances, form the wireless networks of the future fundamental research is required to ensure that a terminal remains connected when it moves, and that interference generated when a large number of simultaneous transmissions are ongoing is mitigated effectively, or that random blockage does not cause link failure. Lastly, there are a number of challenges that come with the large increase in LiFi access points. Specifically, the many access points must be connected to the network backbone via suitable backhaul connections. LiFi systems that are composed of laser transmitters and solar cells as data receivers are envisaged to be a key for the backhaul challenge. It is these latter considerations which will also facilitate the eradication of the rural divide which currently prevents 60% of the world population from accessing digital communications.There are presently no viable solutions to these fundamental problems, and this is where this Fellowship extension comes in by taking the current internationally leading achievements to the next level. LiFi is now at the stage at which WiFi was 20 years ago, and the work undertaken in the next few years will be crucial in making this technology a success.