Accurate Channel Estimation for Frequency-Hopping Dual-Function Radar Communications

Dual-function radar communications (DFRC) is proposed recently to embed information into radar waveform, and hence performs data communications by sharing radar apertures and frequency resources. Exploiting a frequency-hopping (FH) MIMO radar, DFRC can achieve the symbol rate that is larger than the radar pulse frequency. However, this requires an accurate channel estimate, which is challenging to achieve due to the radar-prioritized transmission and the fast-changing FH waveform. In this paper, we propose an accurate channel estimation method for the DFRC based on FH-MIMO radars. We design a new FH-MIMO radar waveform which incurs no change to the ranging performance of the radar. The new waveform also enables a communication receiver to estimate the channel without knowing the pairing between hopping frequencies and antennas. We also develop a new angle estimation method at a single-antenna communication receiver using as few as one symbol, i.e., a single hop. Simulations are provided to validate the efficacy of the proposed channel estimation method. Specifically, the symbol error rate achieved based on the estimated channel approaches that based on the ideal channel.