Exploiting the properties of reciprocal filter in low-complexity OFDM radar signal processing architectures

This paper explores signal processing architectures for disturbance cancellation and range-Doppler map evaluation in Orthogonal Frequency Division Multiplexing (OFDM) radar. The signal processing chain of an OFDM radar typically encompasses a disturbance cancellation stage followed by the range-Doppler map evaluation, which can be in turn decomposed into a range compression stage performed at OFDM symbol level and a Doppler processing across symbols. In this work we use a Reciprocal Filter (RF) to perform the range compression and we deepen the understanding of the RF properties with particular reference to their impact on the other processing stages of the signal processing scheme, above all disturbance cancellation. By exploiting this understanding, we show that it is possible to create synergies between different processing stages, even swapping their order, with the aim to improve the performance of the system while keeping limited its complexity. Thanks to this strategy, alternative versions of existing disturbance cancellation algorithms can be considered that would not be feasible in conventional architectures. Moreover, this study makes it possible to include within the same interpretative framework approaches that seem to be very distant from each other in terms of processing techniques thus allowing their throughout comparison both in terms of target detection performance and in terms of computational complexity. The performance of different solutions is investigated and compared against simulated and experimental data for the case of a OFDM radar that parasitically exploits DVB-T signals of opportunity.