Nokia Mobile Networks, Ulm, Germany This paper addresses the processing principles and performance of OFDM based radar, with particular focus on the LTE mobile network base-stations and the use of the LTE downlink transmit waveform for radar/sensing purposes. We specifically address the problem stemming from the unused subcarriers, within the transmit signal passband, and their impact on the frequency domain radar processing. We also formulate and adopt a computationally efficient interpolation approach to mitigate the effects of such empty subcarriers in the radar processing. We evaluate the target range and velocity estimation performance through computer simulations, and show that high-quality target detection can be achieved, with LTE waveform, when combined with the interpolation approach. Impacts of the different LTE carrier bandwidths and number of transmitted LTE sub-frames are also evaluated, together with aggregating up to 5 individual 20 MHz LTE carriers.