A Performance Study of Line-of-Sight Millimeter-Wave Underground Mine Channel

This letter studies the performance of the line-of-sight underground mine channel in the millimeter-wave band. Using a vector network analyzer (VNA) and three carefully chosen antennas, one omni and two horn antennas, we performed measurements at the 40- and 70-m levels in the CANMET mine located in Val-d´Or, QC, Canada. The performance of the channel is studied in terms of its path-loss exponent, shadowing, and capacity. Results prove that the path-loss exponent in an underground mine is smaller than the free-space value. The shadow fading fits very well with the normal distribution. A model of the capacity as a function of the distance between transmitter and receiver is investigated. Channel capacity depends on the multipath characteristics; the capacity found in the narrow environment (70 m) is higher than in the wider environment (40 m). The results also show that it is better to use omnidirectional antennas for a wireless communication system in the millimeter-wave band in an underground mine environment.