Enabling multi-service radio access networks with Massive MIMO

Wireless connectivity is currently considered a de-facto capability, enabling people and machines to communicate. Range of applications supported by such Radio Access Networks (RAN) ranges from voice and video calling, content streaming services, banking, cloud data storage, navigation and many more. The volume of data carried by cellular networks delivering the connectivity for such applications grows approximately by 40% every year, which means the data traffic approximately doubles every two years, according to Ofcom.

Research and development effort within industry and academia has been focussed on technologies capable of meeting this growing demand for capacity, delivering innovations in digital signal processing, computer science, optical transmission, circuitry, and antenna technology. Spectral efficiency, which is the amount of information that can be carried in a radio channel, has been the key focus for such inter-disciplinary effort since radio spectrum is a scarce resource and has to be used efficiently. Active Antenna Systems (AAS, also referred to as Massive MIMO) is the latest generation of base station technology for mobile networks delivering increased spectral efficiency by combining innovations and experience from multiple disciplines. AAS are already being rolled out as part of 5G network deployments globally and will continue to play a key role in future generations of mobile networks. However, in order for investment in mobile networks to be viable, more services need to be able to use mobile network efficiently, calling for support for multiple services to be concurrently delivered over the same cellular infrastructure. Practical potential of AAS to concurrently deliver multiple services is the focus of the original FLF.

Sustainability has emerged as a key theme in recent years with a view to reduce carbon emissions by a substantial amount to help reverse the negative impact of industrialisation on the climate. In mobile networks this has resulted in energy efficiency (EE) becoming a key design objective. With 0.8% of the overall UK energy consumption falling on BT network alone, finding both short and long-term solutions to this challenge is of critical importance. The specific challenge for RAN is to minimise the consumption of electrical power while also meeting increasing demand for diverse connectivity services.

This project will focus on ambitious enhancements to practical mobile network. The aim of the renewed fellowship is to increase the practical EE of diverse connectivity services provided by mobile networks - from traditional delivery of bits over the wireless interface, to provision of non-data bearing services such as positioning. To achieve this goal, the project will establish practical EE benchmarks for data and service provision in current mobile networks, and then assess and develop approaches to improve the EE, both in short and long term. Specifically, technologies such as muting of transmitters, sending base stations to varying states of sleep will be considered as reference capabilities available in short term, while the use of AI to tailor transmission technology and the use of energy-efficient waveforms with be considered as longer-term research objective aiming the development of 6G air interface.

Applications and benefits from this project will include benchmarks for EE gains from key technology choices under practical operating conditions and constraints. This will enable a realistic assessment of potential contribution to sustainable RAN, and also help design EE-native communication and network deployment strategies for 5G and 6G RAN.