Spatial Coexistence of Cooperative Radar and Communication Systems

Future generations of cellular systems need to meet stringent requirements for bandwidth and latency. This entitles maximum utilization of the available wireless spectrum. Given that some of the spectrum bands are underutilized, e.g. radar band. In this paper, we study the utilization of the radar spectrum for commercial cellular usage for meeting future generations of cellular systems' spectral demands. We propose to avoid destructive high power interference from seaborne radar transmitters with high power that can saturate the cellular base station receivers by using a projection based approach. Additionally, in our design, the radar transmitters will be cooperating with cellular system by transmitting useful broadcast communication signal. Towards that, we study the channel between seaborne multiple input multiple output (MIMO) radar system and MIMO cellular systems. The high power radar signal is projected onto the small singular value subspace of the channel, and therefore, reaches the base station with low power. In our design, the small singular values are selected so that the received power at the cellular base stations is within acceptable cellular system power constraints. Simulation results show that the amount of power transmitted from the radar to the base station increases as the threshold increases, which allows the radar to be cooperatively capable of transmitting communication signals to cellular base stations. Moreover, as the threshold increases, the accuracy of localizing the radar target increases.