Channel modeling of light signals propagating through a battlefield environment: Analysis of channel spatial, angular, and temporal dispersion

Free-space optical communication (FSOC) is used to transmit a modulated beam of light through the atmosphere for broadband applications. Fundamental limitations of FSOC arise from the environment through which light propagates. We address transmitted light signal dispersion (spatial, angular, and temporal dispersion) in FSOC that operates in the battlefield environment. Light signals (photons) transmitted through the battlefield environment will interact with particles of man-made smoke such as fog oil, along the propagation path. Photon-particle interaction causes dispersion of light signals, which has significant effects on signal attenuation and pulse spread. We show that physical properties of battlefield particles play important roles in determining dispersion of received light signals. The correlation between spatial and angular dispersion is investigated as well, which has significant effects on receiver design issues. Moreover, our research indicates that temporal dispersion (delay spread) and the received power strongly depend on the receiver aperture size, field of view (FOV), and the position of the receiver relative to the optical axis of the transmitter. The results describe only specific scenarios for given types of battlefield particles. Generalization of the results requires additional work. Based on properties of the correlation, a sensitive receiver with a small FOV is needed that can find the line-of-sight photons and work with them.