Electromagnetic Information Analysis for Joint Communication and Sensing in Complex Scattering Environments

This study addresses a limitation in Shannon information theory by characterizing electromagnetic information metrics for the joint communication and environmental sensing in complex scattering environments. We specifically characterize how the uncertainty introduced by a dynamic scattering environment affects these metrics, departing from classical methods that treat additive white Gaussian noise as the primary uncertainty source at the receiver. Our analysis examines electromagnetic information transfer within an environment containing multiple scatterers whose positions change rapidly, causing fast fluctuations in channel characteristics. The proposed framework eliminates the necessity of assuming ideal channel coherence times for deterministic estimation or employing cumbersome channel state forecasting. Mutual information metrics are derived using conditional probability distributions to quantify both the information transfer between source and receiver and the inference of environment properties (characterized by the scatterer density in this study) at the receiver. The scattering environment is modeled with randomly distributed spherical dielectric scatterers positioned between a pair of static dipole antennas. Scattered fields are computed using the Foldy-Lax multiple scattering theory in Monte Carlo electromagnetic simulations. Key results are compared against single-scattering approximation counterparts to illustrate the significance of incorporating comprehensive scattering physics in information modeling. Source symbols encoded via M-ary amplitude-shift keying and M-ary pulse amplitude modulation are processed non-parametrically at the receiver by estimating conditional probabilities from electric field data using kernel density estimation. The framework demonstrates robust communication performance in dynamic scattering regimes while maintaining reasonable environmental sensing capability from the same electromagnetic fields, establishing a foundation for a novel environment-aware communication system.