Maximizing Mutual Information of Radar via Optimal Training-Based On–Off Transmissions

The paper considers the joint radar and training-based on-off communication system, where the on-off threshold and training is optimized to maximize the mutual information of radar while ensuring communication quality. The closed-form expressions of communication throughput under finite blocklength and radar’s mutual information are derived. The results show that the training and on-off transmission help improve the radar’s mutual information remarkably. The results also show that the improvement of radar’s mutual information is particularly pronounced at low communication power regimes, where a high on-off threshold can maximize average throughput while allowing ample time for radar transmissions.