The dramatic improvements in capacity (as much as 1000x the current level) and spectral efficiency that are needed for future wireless communication systems to accommodate the rapidly increasing number of wireless electronic gadgets and users who require access to ubiquitous high-speed wireless links can be achieved by adopting mm-wave (mmW) massive multiple-input multiple-output (MIMO) technologies. The realization of mmW massive MIMO requires a radical change in base station architecture wherein hundreds of power amplifiers are required to feed a large array of small antennas. The development of mmW massive MIMO transceivers has been hampered to date by the power amplifier's (PA) poor efficiency and high implementation cost. Nonlinear switch-mode power amplifiers (SMPAs) such as Class E and F offer high efficiency but require fast (power-hungry, expensive) transistors to allow the generation of higher order harmonics. Moreover, an abrupt drop during ON-to-OFF or OFF-to-ON transition in the idealised switch current or voltage waveform of existing SMPA topologies results in substantial power dissipation in the practical implementation, and hence reduces the PA efficiency. The proposed research ambitiously aims to produce a new type of highly-efficient, highly-linear power amplifier that offers true soft-switching characteristics to permit the use of low-cost, slow-switching transistors for effective deployment in mmW massive MIMO systems and thus open the way for very power-conservative high-performance systems.

Potential Impact:
Successful outcomes of this research will catalyse widespread exploitation of mmW massive MIMO, enabling access to global ubiquitous ultrafast wireless links which provide a platform for easy access to a wide range of information and entertainment, convenient online shopping experience, to name few. The proposed concepts can also be adopted for other mmW applications such as intelligent transport systems, autonomous vehicles, and health monitoring systems which will have essential roles in enhancing the overall quality of people's life.

Signal coverage has been a persistent problem since the first ever mobile phone call was made in Britain 30 years ago. Last year, the UK government and mobile networks struck a £5bn deal to tackle this issue. The proposed low-cost mmW massive MIMO technology will benefit the end-users of wireless communication systems by delivering improved quality of service (QoS) including better signal coverage, faster data rate and enhanced efficiency.

Through synergistic collaboration with the industrial partner, prospective commercialisation pathways for the proposed technology have been identified. Successes in this project would accelerate the translation of massive MIMO research into new products. In addition, it is anticipated that the innovative concepts proposed in this research would generate IP which could then lead to the creation of a spin-out company or licencing opportunity. The funding also provides the opportunity of developing the PI's independent research career in a new area of endeavour as well as the development of the career of the appointed postdoctoral researcher in both technical and soft skills.