ICI-Robust Transceiver Design for Integration of MIMO-OFDM Radar and MU-MIMO Communication

By virtue of the low cost and flexible deployment, unmanned aerial vehicles (UAVs) are becoming the most promising platform for active radar sensing to find targets in shaded areas and build a temporary communication infrastructure at disaster sites. Radar and wireless communication are essential functions for reliable control of UAVs and real-time exchange of sensed measurements. However, due to the limited payload and power budget of UAVs, it is impossible to mount two individual radar and communication systems, especially on small- or medium-sized UAVs. Recently, joint communication and radar (JCR) systems have emerged as a breakthrough, which perform the communication and radar functions simultaneously on the same hardware platform. Compared to a simple combination of individual communication and radar systems, a UAV JCR system can minimize the implementation cost, power consumption, payload, and radio resource usage. This paper proposes transmit beamformer and receive beamformer designs for a UAV network composed of a UAV JCR base station, a target, and multiple user equipments. Specifically, the UAV transmits an orthogonal frequency division multiplexing (OFDM)-modulated waveform with transmit and receive beamforming to perform multi-input multi-output (MIMO) radar and multiuser-MIMO (MU-MIMO) communication functions simultaneously. Unlike the previous OFDM radar scheme that employs the communication symbol repetition method, a novel receive beamformer design is proposed to resolve the inter-carrier interference problem in the range/velocity estimation process, which therefore does not sacrifice the communication transmission rate. As a result, simulation results show that the proposed scheme achieves a higher radar signal-to-clutter ratio while achieving a higher communication sum-rate than existing schemes.