DFRC Signaling Strategies Based on MIMO Beampattern Invariance
Sana Mazahir, Sajid Ahmed, Mohamed‐Slim Alouini · IEEE Transactions on Communications · 2025
The Dual-function radar communication (DFRC) design aims to exploit the tractability and reusability of both radar and communication systems’ components, parameters, and spectrum to achieve an integrated system. In this work, we propose a novel DFRC signal design by leveraging the phenomenon of the MIMO beampattern invariance, which was comprehensively explored in our previous work. It is demonstrated that the flexibility afforded by this beampattern invariance can be used to construct an integrated waveform while maintaining the required beam. A beampattern-preserving unitary transformation of the MIMO weight matrix is proposed to realize a desired information-bearing symbol at the communication receiver. The proposed method has the following promising features: 1) low-complexity, closed-form solution for the transmitted signals; 2) flexibility of modulation scheme; 3) independence from the type of orthonormal MIMO waveforms; 4) independence from the beampattern design; 5) adaptability for multi-target and multi-user scenarios. Using this generic signal design method, a number of modulation schemes are implemented. Furthermore, the impact of this operation on the estimation accuracy of the target parameters is analyzed by computing their respective Cramer-Rao Lower Bounds (CRLBs). Simulation results show that modulation schemes yielding a range of symbol error rate (SER) performances can be implemented while keeping the radar parameter estimation unaffected.