Orthogonal Chirp Division Multiplexing Assisted Dual-Function Radar Communication in IoT Networks

The dual-function radar communication (DFRC) system utilizes a hardware platform to achieve both radar and communication functions. In comparison to independently exploiting radar and communication systems, the DFRC system can significantly reduce system redundancy, volume, weight, and energy consumption. This makes DFRC an important area of research with practical value in advanced Internet of Things (IoT) techniques. This article explores an exemplary DFRC system based on the orthogonal chirp division multiplexing (OCDM) methodology. In this system, OCDM achieves chirp multiplexing through the Fresnel transform and is identified as a potential replacement for orthogonal frequency-division multiplexing in high-speed communication systems. In the proposed system, we integrate index modulation (IM) into the communication subsystem and utilize the subchirp index of OCDM to convey additional communication information, thereby significantly enhancing the communication rate of the DFRC system. Furthermore, a radar processing algorithm utilizing the OCDM signal is developed. This algorithm integrates the sparsity-aided compressed sensing (CS) algorithm into the radar subsystem to enhance estimation precision and reduce the sampling rate and hardware complexity of the radar receiver. Based on the proposed OCDM-assisted DFRC scheme, the communication rate of the DFRC system and the ambiguity function of OCDM are evaluated. The feasibility and effectiveness of the proposed DFRC system are confirmed through numerical calculations and simulation results.