A Measurement Study of User-Induced Propagation Effects for UHF Frequency Bands

Understanding user-induced effects on signal reception across multiple frequency bands is of great scientific and military importance to the wireless industry. Various on-body locations and directional heading of the user are believed to impact the performance of mobile devices, but there has been little work across multiple frequency bands to quantify these user-induced effects. In this work, we perform a measurement study to explore user effects on radio wave propagation with varying line-of-sight conditions and environments across multiple frequency bands, including white space (500 and 800 MHz), cellular (1800 MHz), and WiFi (2400 MHz) frequency bands. To do so, we first conduct a baseline experiment that characterizes the propagation channel in this environment. We show that the propagation differences for ground- to-ground communication (common in Ad Hoc and WiFi scenarios) and tower-to-ground communication (common in cellular scenarios) are frequency dependent. Then, we measure signal quality as a function of the on-body location of the receiver, directional heading of the user with respect to the transmitter, vegetation type, frequency band, and propagation distance. Our assessment reveals that the user directionality with respect to the transmitter can reduce received signal strength up to 20~dB and reduce throughput by 20.9\% at most. We also find that the body can act like an antenna, increasing reception by 4.4~dB and throughput by 14.4\% over a reference node at the same distance. Since our study spans many critical (UHF) frequency bands, we believe these results will have far- reaching impact on a broad range of network types.