Measurement-Based Path Loss and Delay Spread Propagation Models in VHF/UHF Bands for IoT Communications

Internet of Things (IoT) holds a great promise in providing autonomous and ubiquitous connectivity between devices in future communication systems. Due to the spectrum scarcity, very high frequency (VHF) and ultra high frequency (UHF) bands are viewed as valuable resources for IoT communications, especially to connect to distant locations that are hard to reach using higher frequencies. Existing propagation models in the VHF/UHF frequency bands are mainly for broadcasting and cellular systems with high transmit antenna heights, and hence, they are not suitable for IoT communications characterized by low antenna heights at both the transmitter and receiver. In this paper, we present new statistical path loss and delay spread models for IoT communications based on quasi-simultaneous wideband channel measurements conducted in the VHF/UHF frequency bands (from 37.8 to 370 MHz) at the city of Halifax, Canada. In particular, we present two log-distance path loss models (frequency-independent path loss exponent and frequency- dependent path loss exponent), as well as, a new statistical distribution of the delay spread.