Full Duplex Radio/Radar Technology: The Enabler for Advanced Joint Communication and Sensing

The use of joint communication and sensing (JCAS) systems in efficiently utilizing the scarce RF spectrum has received increased interest in recent years. Due to the (re)use of the same resources by both functions (e.g., frequency of operation, waveforms, and hardware), various design challenges are evident in integrating communication and sensing/radar systems, and novel techniques are required to overcome them to provide both subsystems with optimal performance. We have identified full duplex operation as the key enabler for JCAS systems as discussed in this article. Furthermore, since JCAS systems usually employ large antenna arrays, novel beamforming techniques are required to efficiently manage the sensing and communication beams in addition to self-interference suppression, whereas their joint waveforms need to be optimized considering the performance metrics of both subsystems. These requirements yield design trade-offs to address; existing and novel solutions to these aspects are explored herein from a signal processing perspective. This article also presents experimental full duplex sensing results through over-the-air RF measurements, showcasing the feasibility of integrating sensing systems with communication systems.