There is insufficient radio spectrum below 6GHz to cater for future mobile communications demand. Researchers are also now beginning to consider the needs of the 2030 intelligent information society, which will likely include a further push into sub-terahertz radio spectrum, to deliver yet more user data bandwidth. In 5G, future 6G and beyond, use of millimetre wavelength (mmWave) bands in fixed wireless access and handheld equipment will require power efficient, low cost yet high-performance RF transceivers. Such transceivers must also support extremely high data rates (e.g. Gigabit Ethernet; 5Gbit/s for USB 3.0; 10's of Gbit/s peak rates for vehicular 'infotainment' and '8k' ultra-high-definition TV for virtual reality). This challenging set of requirements has, to date, been mutually exclusive in all conventional mmWave technologies. With the release of early 5G smartphones, such as Samsung Galaxy S10 5G incorporating 28GHz / 39GHz communication radios (bands n257-n261), the era of mmWave mobile communications has begun. Although entry-level 5G is in early stage deployment (using modifications to 4G), it is unlikely to be defined or viable for deploying at high mmWave bands (circa 73GHz) before 2030. Initial analysis shows the digital signal processing (DSP) required for multi-Gbit/s data may extend to 10's of billions of 'multiply-accumulate' instructions per second. When combined with analogue radio functions, this could result in consumed battery powers of 14W by receive functions alone, with considerably more for transmit. Smartphone battery capacities are now circa 4.5Ahr, which would support just 1 hour of operation at such consumed receive powers. Thus, there is an urgent need for new research into mmWave radio hardware and software architectures, for frequencies at E band (circa 73GHz) and beyond. The Fellowship will focus on the following areas:- 1) Cost-effective and power-efficient techniques to form mmWave antenna arrays. Our recent research into Time Modulated Antenna Arrays (TMA) has shown ways of improving TMA efficiency at lower frequencies. A key attraction of the TMA is its simplicity of control interface (all digital). 2) Reinvestigation of fundamental mmWave circuit concepts, such as mixers and oscillators, using new insight and making use of the latest findings for manufacturing key components such as resonators. The research in resonators at mmWave could now benefit from the latest 3D printing techniques available at the University of Sheffield as well as updated techniques in low temperature co-fired ceramics. 3) A holistic view of the mmWave transceiver in terms of hardware and software, with partitioning to give best power efficiency for an RF performance target. Novel techniques will be valuable in saving power in massive multiple-input multiple-output systems (M-MIMO), having many hundreds of antennas and transceivers. In existing M-MIMO systems the power consumed by RF hardware could rival that of the digital signal processors. Research will include reconsidering long-forgotten circuit topologies and ideas, in this new setting. 4) Exploration of signal processing techniques for mmWave cognitive radio- allowing it to sense its operational environment and optimise its performance (via reconfigurable RF hardware). Also, the emergence and increase in capability of artificial intelligence is now becoming relevant for operation closer to the hardware itself, such as in demodulating an incoming RF signal. 5) Prototype test chips and subsystems will be created during the project. These will be used to build mmWave radio system demonstrators, including for propagation measurement research. The post-fellowship application for the trial platforms will support further research in future mass-producible mmWave systems, as well as facilitating enhanced industry engagement.

Fast data rate communication over wireless networks like 5G and WiFi has become immensely important to our society, influencing livelihoods, economy and security on every level. The recent experience of home working has highlighted our dependence on reliable and resilient high-speed connectivity, in particular, real-time and streaming video services over wireless networks. These trends are set to grow and with them the need for more data traffic in support of the metaverse, holographic telepresence and cyber-physical systems delivered via a global network of networks. To address this future internet, research into 6G networks is underway and central to this new connectivity paradigm is the use of sub-terahertz electromagnetic waves, which bring bandwidths above 10GHz to achieve data rates above 1 Tbit/s. At the heart of realising the 6G ambition is the design of the radio system from the choice of waveform, through transceiver circuits and signal processing to protocols for controlling the flow of data over the air-interface. The SDR6G+ facility proposed here aims to support the UK's academic and industrial sectors undertaking research and development into 6G radio systems by providing a versatile capability to experimentally test at full scale and across realistic environments all aspects of the radio system performance. The facility will enable users to take research from fundamental concepts at Technology Readiness Level 1 to technology demonstration at Technology Readiness Level 6, thereby accommodating academic and industry interests. These capabilities will be achieved via a cutting-edge SDR platform incorporating advanced waveform generation, multiple over-the-air sub-terahertz paths, extreme wide bandwidth digitisation and software control of the signals and system. These capabilities allow full performance characterisation at the system as well as device and component level. The versatility of the SDR6G+ platform will enable different types of users to experimentally evaluate their research concepts and prototypes. For example, user groups studying waveforms will be able to synthesise new waveforms and evaluate their behaviour and resilience over realistic sub-terahertz channels. User groups researching power amplifiers, low noise amplifiers, bandpass filters and antennas will be able to characterise their devices and assess their impact on 6G radio performance. Users researching digital acquisition will be able to test direct sub-terahertz sampling schemes to determine optimum SDR architectures. Users studying medium access control protocols will be able to measure throughput performance on realistic end-to-end transmission channels. A major facet of the facility will be its ability to produce raw data for machine learning/ artificial intelligence applications used at the Physical layer. The facility is both timely and important and will position the UK at the international forefront of new radio systems research and development for 6G networks and beyond. The facility will support the UK requirement for national capabilities in advanced wireless communication systems aimed at addressing major challenges in a rapidly changing international landscape. For example, to develop energy efficient radio technologies for disaggregated network standards, which facilitate the UK's supplier diversification and 2050 net-zero targets. The facility will support a broad cross-section of the UK telecommunications industry including mobile radio and satellite vendors, and their supply chains. Importantly, the facility will train and inspire diverse cohorts of future UK academic and industrial leaders and innovators in a holistic, collaborative, and vibrant cross-disciplinary environment.