Rough surface scattering from exterior walls at 28 GHz

In this study we investigated the Local Multipoint Distribution Service band (28 GHz) rough surface scattering properties of limestone and brick walls. Our ultimate goal is to understand the characteristics of radio paths that involve one or more bounces from these walls. In the experiment described here, we processed impulse response data to produce power delay profiles and calculate relevant channel metrics. In particular, we investigated the scattered signal behavior for different incident angles and transmitter-receiver geometries. Using the reflected pulse width and maximum excess delay derived from each power delay profile, we found that limestone and brick walls exhibited measurable diffuse scattering. The reflected pulse from a limestone wall has more maximum excess delay spread than does a brick wall at the -15 dB power threshold. The mean maximum excess delay for the reflected pulse for the limestone wall measurement configurations was more than twice that of the brick wall. With equal transmitter and receiver distances to the wall, we found that the maximum excess delay decreased and the perpendicular reflection coefficient increased with incident angle.