High Dimensional Wireless Passive Optical Networking for Access Deployment (PON-HD)

By 2035, a challenge has been set for the UK to have "full-fibre" deployment across the entire country providing 1Gbps internet connectivity. British Telecom's Openreach division is responsible for achieving this ambitious target. However, deploying optical fibre has huge infrastructure costs that, in many areas, could be not economically viable due to terrain, low population density or land rights issues. After comprehensive analyses of the UK's communications network, BT has identified critical areas in the network where FTTP would be challenging, and expensive to deploy. Achieving this goal sustainably, will require new technology that can reduce the costs of deployment in rural areas, and assure network resilience.

In this project, we will develop Free-space optical (FSO) solutions that can be seamlessly integrated into Passive Optical Networks (PON) to provide network access to customers in rural and urban areas that will not be serviced by fibre to the property (FTTP). FSO optical systems can provide higher capacity then radio systems, however deployment has four main technical challenges, (1) stringent alignment requirements, (2) Adversely effected by atmospheric turbulence, (3) Power Loss due to fog and scattering particulates in the air, and (4) Seamless network integration.

In this project we will resolve these long standing challenges by pioneering new technologies for broadband amplifiers for long distance free-space extension of XGSPON, dynamic optical beam shaping to overcoming turbulent affects in FSO propagation, develop novel error correction codes for PON systems, and produce a self-aligning FSO prototype that can be installed into the BT network in less than 30mins. Providing these new connections will require both point-to-point (p2p) links and point-to-multipoint (p2mp) links to service rural areas, and dynamic optical mesh networks for more urban areas. Such, areas could be addressed with high capacity FSO links to provide optical connection from exchanges to local cabinets, direct to the property deployment and emergency link deployment for cable cut situations. Our FSO system will be extended to overcome fibre failure in both the back-haul and core networks increase resilience in the optical network as a whole.

The technology we will develop has broad application beyond the extension of PON into free-space. Firstly, our amplification technology will have immediate usage for enabling long-reach PON and be used for the amplification of space division multiplexing in fibre, which is a hot topic in the fibre optical communications community. Secondly, our all-optical-mimo technology will have application in a range of optical sensor and communication technologies including: Lidar, Quantum Key Distribution, advanced endoscopy imaging system, remote environmental sensing and many others. Thirdly, our novel digital signal processing techniques will have application in for a wide range of communication systems.

This program was conceived to develop enabling technologies that could be pivotal in shaping the future of our communication networks and promote access of them to rural communities. The big data society places critical challenges in maintaining high speed, secure communication networks, particularly through the internet (which has become our primary means of communication and data transfer). The online services we use on a daily basis including Netflix, iTunes and Spotify are huge users of network bandwidth; in 2014 44% of all adults in the UK were using such streaming services. This high usage of streaming services quickly places great strain on networks where standard definition video content uses around 1GB of data per hour (and 3GB per hour for high definition). With cloud-based storage and computing becoming the norm, extremely high-bandwidth communication networks will be vital in the future. Under Horizon 2020 the EU has designated Secure Societies, with a focus on information security, as one of their seven priority challenges, where Digital Economy & Society is a major area with an allocated budget of over 6 Billion euro. Maintaining the UK's leading position in these emerging communications technologies is vital. This level of investment, specifically focusing on communications technology is mirrored in the USA and other research led countries around the world. PON-HD will specifically address the network access requirements for rural and low-connectivity areas to minimize the digital divide within the UK and support the economic development of these communities. Our technologies will be designed mindful of the global challenges of rural digital connectedness and, where approaches to development of low cost and open sourced optical technologies are integrated into the project plan.

Strategic investment in emerging technologies within the communications sector has been a focus of global research funding both in the academic and industrial sectors. Big Data and the novel technology that supports it, such a high speed access networking objective in PON-HDs, is an EPSRC Engineering Grand Challenge. The technologies we will pioneer, will have direct impact in the provision of sustainable optical networking that could revolutionise the access network in poor and rural areas. This vision was recently published as a central part of road map for sustainable network expansion for rural communities in Nat. Photonics (Lavery et. al, N. Photon. 12(5), 249-252, 2018) developed by Dr Lavery and Prof Ellis and co workers. Our novel approaches to network deployment will support the develop of protectable IP and working with BT will develop system prototype access technologies that could be taken forward by SMEs or startups, in the growing area of optical networking for rural communities and developing nations.