ECE Distinguished Professor Athina Petropulu is a co-author of the paper "Toward Dual-functional Radar-Communication Systems: Optimal Waveform Design" that was selected to receive the 2021 IEEE Signal Processing Society Young Author Best Paper Award. The paper published in the IEEE Transactions on Signal Processing, August, 2018, is co-authored by Fan Liu, Longfei Zhou, Christos Masouros, Ang Li, and Wu Luo. The young authors Liu, Zhou and Li are affiliated with Beijing Institute of Technology, Peking University and University College of London.
The paper deals with an emerging trend in next generation wireless systems that includes sensing as a primary function, thereby adding a new dimension to the system capabilities. This has prompted intense research interest in integrated sensing-communication systems, i.e., systems in which sensing and communication functions share the majority of hardware. In scenarios with a large number of sensors and communication transceivers, the integration of radar and communication functionalities in one system can reduce device size, power consumption, and cost, while there is no need to address interference between the two systems. The paper focuses on a special case of such systems, namely, Dual-functional radar and communication (DFRC) systems. A DFRC system transmits a waveform which can be used to detect targets and at the same time, convey information to some receiver. However, designing waveforms that meet the radar constraints and also deliver high rate information is a challenging problem. The paper proposes optimal waveform designs for multiple-input multiple-output (MIMO) DFRC systems, which can support multi-user downlink communications, while guaranteeing a certain level of target sensing performance. Several waveform designs are proposed that minimize the multi-user interference (MUI) and meet MIMO radar waveform constraints, including omnidirectional waveform design, directional waveform design, tradeoff design with total/per-antenna power budget, and constant-modulus design. For omnidirectional/directional waveform designs, optimal closed-form solutions are derived. For tradeoff design with per-antenna power constraint, an efficient Riemannian Conjugate Gradient (RCG) algorithm is proposed by exploiting the manifold structure of the feasible region. Via numerical simulations, it is shown that the proposed DFRC waveform designs can achieve a flexible performance tradeoff between radar sensing and communication, rather than being restricted to be radar-optimal or communication-optimal, as was the case in previous works.