Design of In-Band-Full-Duplex IAB Networks for Integrated Sensing and Communications

This paper proposes a 3GPP-inspired design of the in-band-full-duplex (IBFD) integrated access and backhaul (IAB) networks for integrated sensing and communications (ISAC) in the frequency range 2 (FR2) band for vehicle-to-everything (V2X) communications. Unlike half-duplex (HD), IBFD-IAB-nodes (i.e., roadside units) in this work are doing sensing and communications at the same time and frequency, which enhance the spectral efficiency (SE) and sensing accuracy, as well as reduce the latency. With the help of the extended Kalman filter (EKF), radar sensing is performed at the IBFD-IAB-nodes for the multi-vehicle scenario. Assuming the high power self-interference (SI) at the IBFD-IAB-node has been successfully canceled in the propagation, analog, and digital domains, only the residual SI is reserved in this work. Numerical results show that the closer the vehicle to the IAB-node, the higher the SE it can get. Compared with HD ISAC-IAB systems, our proposed IBFD ISAC-IAB systems can double the SE at the vehicle.