A cellular macro base station (BS) serves a multiplicity of micro base stations and a micro base stations serves terminals (like relay systems) over the same time-frequency interval and dual polarizations. The reason why the dual-polarized antenna systems in the wireless backhaul network are adopted is that when transmitting and receiving a signal, by selecting either one of the two modes of the vertical polarization and horizontal polarization, the cell capacity can be raised against the limited frequency resource. Channel information contains fast fading, cross polarization discrimination, log-normal shadow fading and geometric attenuation. In case that there are pilot contamination due to transmission of the micro BS to use the same pilot sequence in the other cell, we analyze the effect of an infinite number of dual-polarized antennas. As a result, the effect of uncorrelated noise and fast fading vanish, but intra-cellular interference and inter-cellular interference due to imperfect polarization and slow-fading remain. Also we analyze the trade-off between the number of antennas and pilot training time.