Evaluating Communication and Sensing Quality in Phase-Modulated FMCW Radar

This paper presents an integrated communication and sensing (ICAS) system combining traditional radar sensing and communication. This system is built on existing conventional hardware, with only a few necessary modifications. Phase modulation is integrated into linear Frequency-Modulated Continuous Wave (FMCW) chirps for an automotive scenario, for which the propagation was characterized in a ray tracing simulator. The phase modulation is added in slow-time, fast-time, and a combination of both. The results show that integrating phase modulation increases the sidelobes, resulting in an increased noise floor of up to 8 dB for a higher number of bits. The Bit Error Rate at the Signal-to-Noise Ratio of 20 dB is between $8 \cdot 10^{-3}$ and $4 \cdot 10^{-5}$ depending on the number of bits per chirp. These results show that the proposed system can add communication to FMCW radars, but some trade-offs are necessary between the sensing and communication performance to improve the spectral efficiency. These results give a more detailed understanding of whether phase modulation suits an integrated communication and sensing approach in the automotive context.