OFDM Radar Sensing in Joint Communication and Sensing Systems Without Cyclic Prefix Overhead

We consider an approach for realizing radar sensing in orthogonal frequency-division multiplexing (OFDM)-based joint communication and sensing (JCAS) systems. In such JCAS systems, the performance of radar sensing is limited by the OFDM cyclic prefix (CP) length. We propose a sensing system that exploits OFDM communication symbols, which are known by the sensing transceiver. These symbols have a CP length originally designed for communication. In the proposed method, a matrix using the transmitted communication symbols is constructed for radar sensing, avoiding the need of reserving sensing symbols. The proposed method results in achieving the maximum achievable range without loss of data throughput. In the scenario of our simulations, we show that the proposed method achieves a measurable distance approximately 14 times higher than a conventional OFDM radar sensing approach when no modifications are made in the transmitted data. When sensing symbols are reserved in the conventional approach to increase its maximum unambiguous distance, the proposed method shows a throughput gain of approximately 7% with respect to the conventional method.