Atmospheric Effects on Signal Propagation in Adverse Environmental Conditions: A Validation of the Advanced Refractive Effects Prediction System

摘要

Signal propagation measurements from an 802.16 wireless communications network link were analyzed and compared with respect to effects- based model outputs influenced by atmosphere conditions. Atmospheric data collected included in situ ground measurements, radiosonde upper air observations, and numerical weather model data. Extrapolated vertical atmospheric profiles, based on boundary layer constant flux theory and using the in situ ground measurements, were compared to the radiosonde upper air observations and high resolution numerical weather model data for consistency and accuracy. All three sources of data were input into the Advanced Refractive Effects Prediction System (AREPS) which uses the Advanced Propagation Model (APM) to predict radio frequency (RF) signal loss. AREPS output was compared with measured network signal data. The network studied was part of the COASTS 2007 field experiments in Northern Thailand, a region of highly varied terrain and vegetation as well as adverse environmental conditions. Results validate the extrapolated atmospheric profiles for use as input into tactical decision aids; provide a real-time assessment of the boundary layer and refractive layers overland; and compare high resolution numerical model data with radiosonde upper air profiles in the data sparse environment. Results validate AREPS as a Tactical Decision Aid and tool for network administrators and operators for RF signal propagation; determine a negligible statistical significance of refractivity condition impact even though in situ meteorological data captured non-standard refractivity gradients; show that the atmosphere is not a significant contributor to anomalous signal propagation at the operating wavelength and transmission distances; and conclude that the radiation heating of the network equipment remains as the likely factor to impact the transmission signal and equipment.