Delay and Doppler shift estimation for OFDM-based radar-radio (RadCom) system

The joint operation of radar sensing and wireless communication, namely RadCom system, yields a unique platform to meet the requirements of future intelligent transportation networks. Taking advantages of OFDM waveform, the range-Doppler coupling issues can be overcome for radar applications and complex equalization filter is no longer necessarily used to cope with frequency-selective fading channel because of multi-path. This paper presents a technique for simultaneous estimation of the range and Doppler shift of targets using an OFDM-based Radcom system. Unlike the previous method based on fourier analysis to estimate the range and Doppler shift, we derive a subspace-based algorithm by applying a smoothing approach for joint estimation of range and Doppler shift without the pair matching problem. Compared to the previous method, our method is able to at least exhibit the following three advantages: 1) higher resolution for multiple targets, 2) less time-based data, and 3) avoidance of pair-matching techniques. Therefore, this method is more suitable for OFDM-based RadCom systems with high mobility and high data rate. Furthermore, the proposed algorithm is compared with the current counterpart with computer simulations.