Future Millimetre Wave RF Transceiver Architectures for Communications Systems

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.

The rise of '5G' has highlighted the reliance future, high-capacity mobile communications systems will place on millimetre wavelength (mmWave) technology. The development of future systems for 6G and beyond demands new and focused research across both academia and industry- if the UK is to maintain a strong presence in the field. This Fellowship proposal incorporates extensive cross-disciplinary research between radio hardware, signal processing and cognitive radio systems, with a combined focus on achieving cost-effective, power-efficient, high-performance mmWave transceivers. The emergence of AI as a possible tool for use in future signal processing is a further exciting prospect. Such interdisciplinary research and innovation is frequently seen as a pivotal and transformative capability in high-performance commercial R&D organisations and is equally appropriate in an academic setting. There are now global programmes addressing mmWave research- the UK must play a leading role.
Beyond the supporting partners, the UK R&D industrial community value power-efficient mmWave radio, Digital Signal Processing (DSP), AI and Cognitive Radio (CR) concepts for future portable radio systems. Benefiting organisations could include commercial and defence manufacturers: Filtronic Broadband, Rolls Royce, MBDA, Bentley, QinetiQ, Seven Technologies, Leonardo, Thales, Arralis and BAE Systems. Mobile communications equipment designers and manufacturers such as LG, Samsung, Tait, and Sepura will also benefit as well as high tech' design houses such as Cambridge Consultants and Plextek. Integrated circuit manufacturers have informed us of their increased activity in mmWave transceiver design and can benefit, including: Analog Devices, Texas Instruments, Peregrine Semiconductors, Murata, Qualcomm and Silicon Labs. New, innovative design and 'fabless' IC and product manufacturing start-ups could appear. Spectrum regulatory and standards bodies such as OFCOM, FCC and ETSI will benefit from exposure to emerging capabilities of future mmWave transceivers - facilitating better prediction of future paths of radio technology. TUoS Communications, Semiconductors and Materials Research Groups are actively extending their research agenda in mmWave technologies and will also benefit.
The mmWave architectures will be applicable to emerging 5G, Satellite and Radar systems within 5 years, hence could be deployed in global products serving smartphones, laptops, satcom terminals and tablets as well as base station infrastructure: benefiting all of society. By addressing the power efficiency of mmWave transceivers the project will help extend product life, which is vital for commercial success. Over a 5-10 year period, the architectures and signal processing concepts will be refined and applied in the wider radio communications industry, extending into imaging, 6G, sensing and novel healthcare applications.
The partner organisations will benefit from early exposure to industrially-relevant research applicable to next-generation R&D product concepts or cost reductions in existing products. The wider radio design and manufacture community will have the opportunity to benefit from the 2 industry-focused workshops and multiple dissemination activities.
All the team will advance their professional knowledge and external reputations, benefiting both the University and Region and enabling enhanced collaborations with industry and academia: resulting in a centre of excellence forming. The prestige and activities within the Fellowship will enhance the recruitment of high calibre Master and Doctoral research candidates to the University, ultimately leading to an overall capability growth in both the University and industry. Finally, it is expected that many aspects of the research will be included in future taught courses, enhancing their industrial relevance and that of the students we host.