Human Occupancy Estimation with Human Body Mie Scattering Model in Reverberant Environments

Techniques to detect the presence or location of a human come in many forms. Approaches based on measuring radio signals may involve geometric principles considering phase, delay and/or attenuation. This paper extends studies into detecting a human in reverberant environments, without dedicated localization hardware aside from measurement equipment. It utilises scattering parameters measured in loaded and unloaded reverberation chambers. By referencing the loaded data to the unloaded data and comparing that to absorption cross-section found using Mie theory models of spheres filled with water with specified radii, we show that a human body cannot be directly modelled as such. We optimize our model for multiple variables to match the measurements, resulting in a representative sphere with a fixed radius and complex, frequency-dependent relative permittivity that fits the human measurement. Using measurements and multivariable optimisation, permittivity and radius for a given measurement are extracted and compared. A stochastic approach for human occupancy estimation is required due to the uniqueness of people’s RF characteristics. The results are discussed with a focus on estimation and its accuracy given a set of measurements.