Energy-efficient Integrated Sensing and Communication System with DNLFM Waveform

Integrated sensing and communication (ISAC) plays a crucial role in the development of 6G networks. This study focuses on an ISAC scenario that utilizes a dedicated sensing reference signal (SRS). Similar to the position reference signal (PRS) in 5G, the SRS can be repurposed as other communication reference signals, leading to resource savings. However, it is important to note that sensing is more sensitive to power and is susceptible to severe multi-target interference. To address this issue, the paper proposes the incorporation of matched windows at both the transmitter and receiver ends. This approach aims to enhance energy efficiency by mitigating windowing mismatch loss. To achieve arbitrary window shapes in the frequency-domain while maintaining a constant amplitude waveform, the paper introduces discrete non-linear frequency modulation (DNLFM). DNLFM utilizes a limited number of Newton iterations and a geometrically-equivalent method to reduce waveform generation complexity. This method allows for timely adjustment of parameters based on changing sensing requirements. Additionally, the paper proposes the use of spatial-domain matched windows to minimize sidelobes. Simulation results demonstrate that the proposed methods outperform conventional schemes, highlighting their effectiveness in improving performance.