Fair Beamforming Design for MIMO ISAC Systems

In this paper, a fair beamforming scheme for multi-target multi-user Integrated Sensing and Communication (ISAC) applications is designed. In the considered scenarios, the ISAC system simultaneously receives radar echoes and communication signals from other ISAC systems. The considered optimisation objective is the Signal-to-Interference-plus-Noise Ratio (SINR) product, as the product metric naturally ensures fairness among the users and targets. This fairness, as well as the low complexity of the designed algorithm, makes it a good candidate for ISAC tracking applications and codebook design. Numerical analyses are performed, demonstrating the beamforming scheme behaviour in the presence of multiple targets and communication users. The benefit of the SINR-product metric over the SINR-sum is moreover emphasised, together with the robustness of the designed scheme against tracking inaccuracies and codebook discretisation.