Spectrum sharing between S-band radar and LTE cellular system: A spatial approach

Spectrum sharing is a new way forward to solve spectrum scarcity problem. In this paper, we propose a spatial approach for spectrum sharing between a MIMO radar and an LTE cellular system with NBS base stations (BS). The MIMO radar and LTE share NBS interference channels i.e. Hi, i = 1,2, ..., NBS. We propose projecting the radar signal onto the null space of interference channel between the MIMO radar and LTE using our proposed interference-channel-selection algorithm, in order to have zero-interference from the MIMO radar. We select interference channel with the maximum null space i.e. arg max1≤i≤NBS dim [N(Hi)] and project the radar signal onto the null space of this channel. Our proposed spatial spectrum-sharing algorithm is radar-centric such that it causes minimum loss in radar performance by carefully selecting the interference channel and at the same time protects the ith LTE BS from the radar interference. Through our analytical and simulation results we show that the loss in the radar performance is less when the proposed interference-channel-selection algorithm is used to select the channel onto which radar signals are projected.