Three-Dimensional RF Sensor Networks for Widespread Spectrum Monitoring

Spectrum monitoring could improve spectral management and efficiency by enabling spectrum sharing, strengthening policy enforcement, and facilitating data-driven modeling of RF environments. This paper considers spectrum monitoring sensor networks in three dimensions to extend previous work on two-dimensional models. We derive a closed-form expression for the probability of emitter detection, which acts as a metric for system design. We find optimal antenna half-power beamwidths for emitter detection. Additionally, we find that for a path loss exponent less than approximately 3.22, directional antennas are optimal. Otherwise, omnidirectional antennas are optimal. Further, despite potential sub-optimality, omnidirectional antennas are found to be robust in changing environments. Finally, a survey of antenna gain models is evaluated against real antennas to validate the choice of gain model in the paper.