Millimeter‐wave directional‐antenna beamwidth effects on the ITU‐R building entry loss (BEL) propagation model

Abstract

Assuming omnidirectional antenna reception, the ITU‐R recently developed a new propagation model on building entry loss (BEL) for 5G millimeter‐wave frequency sharing and compatibility studies, which is a simplified outdoor‐to‐indoor path loss model. Considering the utilization of high‐gain narrow‐beamwidth beamforming, the omnidirectional‐based ITU‐R BEL model may not be appropriate to predict propagation characteristics for directional beamforming scenarios. This paper studies the effects of beamwidth on the ITU‐R BEL model. This study is based on field measurements collected with four different beamwidth antennas: omnidirectional, 10° horn, 30° horn, and 60° horn. The measurement campaigns were conducted at two types of building sites: traditional and thermally efficient buildings. These sites, as well as the measurement scenarios, were carefully chosen to comply with the ITU‐R BEL measurement guidelines and the ITU‐R building types. We observed the importance of accurate beam alignment from the BEL variation range. We were able to quantify the beamwidth dependency by fitting to a model that is inversely proportional to the beamwidth.

Keywords

• beamforming
• channel model
• outdoor‐to‐indoor propagation
• path loss