Coexistence between Massive MIMO and Radar Communications: Performance Analysis

Frequency spectrum sharing between radar and communication systems has recently attracted substantial attention. We consider the coexistence between a massive multiple-input multiple-output (MIMO) downlink system and MIMO radar to enable the operation of these two systems with minimal mutual interference. Through an asymptotic analysis, we show that by using more antennas at the base station (BS), we can improve the performance of massive MIMO, while keeping the interference to the radar system unchanged. Additionally, if we use a large number of antennas at the BS and make the transmit power inversely proportional to the number of antennas, we can avoid the interference from the massive MIMO system to the radar system, with no compromise in the performance of the massive MIMO system. Closed-form expressions for the probability of detection of the radar system and the downlink spectral efficiency of the massive MIMO system, are derived. Furthermore, we propose a power allocation scheme which selects the transmit powers at the MIMO radar and BS to maximize the probability of detection for the MIMO radar. Interestingly, the optimal power allocation can be determined in closed-form. These results provide valuable insights into the practical coexistence between massive MIMO and radar systems.