  Spectrum sharing between radars and cellular systems is an emerging area of
research. In this paper, we model channel between a seaborne MIMO radar and
MIMO cellular system. We model a 2D channel to capture the azimuth aspect of
the spectrum sharing scenario. Our channel modeling methodology allows MIMO
radar to place accurate nulls in the azimuth location of base stations (BS),
thus, protecting them from harmful radar interference. We use a projection
based approach, where radar waveform is projected onto null space of channel,
for mitigating radar interference to BSs. This is also known as an approach
based on eigen-nulling which is different from spatial-nulling commonly
employed by radars. We show through simulations that the proposed spatial
channel model allows eigen-nulling which performs superior to traditional
spatial-nulling for interference mitigation. The proposed channel model can be
leveraged to use eigen-nulling that enhances target detection and beampattern
resolution of MIMO radar while mitigating interference to BSs.
