Abstract
Spectrum sharing between cellular and radar systems is an emerging area of research. Deploying commercial wireless communication services in radar bands give wireless operators much needed additional spectrum to meet growing bandwidth demands. However, to enable spectrum sharing between these two fundamentally different systems interference concerns must be addressed. In order to assess interference concerns we design a three-dimensional (3D) channel model between radar and cellular base stations (BSs) in which the radar uses a two-dimensional (2D) antenna array and the BS uses a one-dimensional (1D) antenna array. We formulate a line-of-sight (LoS) channel and then propose an algorithm that mitigates radar interference to BSs. We extend the previously proposed null space projection algorithm for 2D channels to 3D channels and show that effective nulls can be placed by utilizing both the azimuth and elevation angle information of BSs. This results in effective interference mitigation. In addition we show that the 3D channel model allows us to accurately classify the size of radar's search space when null space projection algorithm is used for interference mitigation.