MIMO-OFDM ISAC Signaling Design for Reciprocal-Filtering-Based Sensing Receiver

This paper proposes a multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) integrated sensing and communication (ISAC) transmit signaling design under a reciprocal-filtering (RF) radar sensing receiver. In radar sensing, mismatched filtering such as RF can mitigate the range-Doppler sidelobes while suffering from sensing SNR loss compared to the matched filtering (MF) receiver. To tackle this problem, we first derive the closed-form expression for sensing SNR loss at the RF receiver output in terms of MIMO-OFDM transmit signals. Then, we formulate an RF-SNR maximization problem under communication Quality of Service (QoS) constraints with symbol-level precoding (SLP) solved via a majorization–minimization algorithm. Simulation results demonstrate that the proposed design achieves higher sensing SNR compared with existing benchmarks.