Integrated sensing and communication (ISAC) is regarded as the enabling technology in the future 5th-Generation-Advanced (5G-A) and 6th-Generation (6G) mobile communication system. ISAC waveform design is critical in ISAC system. However, the difference of the performance metrics between sensing and communication brings challenges for the ISAC waveform design. This paper applies the unified performance metrics in information theory, namely mutual information (MI), to measure the communication and sensing performance in multicarrier ISAC system. In multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) ISAC system, we first derive the sensing and communication MI with subcarrier correlation and spatial correlation. Then, we propose optimal waveform designs for maximizing the sensing MI, communication MI and the weighted sum of sensing and communication MI, respectively. The optimization results are validated by Monte Carlo simulations. Our work provides effective closed-form expressions for waveform design, enabling the realization of MIMO-OFDM ISAC system with balanced performance in communication and sensing.

翻译：通感一体化被视为未来5G-Advanced（5G-A）和第六代（6G）移动通信系统的使能技术。通感一体化波形设计在通感一体化系统中至关重要。然而，感知与通信性能指标之间的差异给通感一体化波形设计带来了挑战。本文应用信息论中的统一性能度量——互信息，来衡量多载波通感一体化系统中的通信与感知性能。在多输入多输出正交频分复用系统中，我们首先推导了考虑子载波相关性与空间相关性的感知与通信互信息。随后，提出了分别最大化感知互信息、通信互信息以及两者加权和的优化波形设计方案。通过蒙特卡洛仿真验证了优化结果。我们的工作为波形设计提供了有效的闭式表达式，使MIMO-OFDM通感一体化系统能够在通信与感知之间实现性能均衡。