Universal Path Gain Laws for Common Wireless Communication Environments

Simple and accurate expressions for path gain are derived from electromagnetic fundamentals in a wide variety of common environments, including line-of-sight (LOS) and non-line-of-sight (NLOS) indoor, urban canyons, urban/rural macro, outdoor–indoor, and suburban streets with vegetation. Penetration into a scattering region, sometimes aided by guiding, is the “universal” phenomenon shared by the diverse morphologies. Root mean square (rms) errors against extensive measurements are under 5 dB, better than 3GPP models by 1–12 dB rms, depending on the environment. In urban canyons the models have 4.7 dB rms error, as compared to 7.9 dB from linear fit to data and 13.9/17.2 dB from LOS/NLOS 3GPP models. The theoretical path gains depend on distance as a power law with exponents from a small set {1.5, 2, 2.5, and 4}, specific to each morphology. This provides a theoretical justification for widely used power-law empirical models. Only coarse environmental data are needed as parameters: street width, building height, vegetation depth, wall material, and antenna heights.