Measurements and Analysis of Radio Propagation at 28 GHz in Vegetated Areas of Typical Residential Environments

This communication presents foliage channel measurements at 28 GHz using a directional channel sounder. The measurements were conducted in vegetated areas of typical residential environments in Daejeon, South Korea. We first propose a pattern matching algorithm that allows us to overcome the angle resolution of a directional antenna and to estimate a more accurate receiving angle. Then propagation paths received from the vegetation and the surrounding buildings are classified and their power ratios are analyzed. Furthermore, foliage attenuation was determined from the measurement data according to the foliage depth, and appropriate models based on the modified exponential decay (MED) model and the maximum attenuation (MA) model are presented. In addition, the effect of foliage attenuation on seasonal variation is studied. These results will be useful for predicting path losses through the vegetated areas at 28 GHz by modeling the foliage loss as an additional path loss term. Finally, spatial-temporal channel characteristics in a vegetated environment were statistically analyzed including delay spread, coherence bandwidth, and angular spreads.