Spurred by the 2006 Miner Act, reliable two-way communications in mines has drawn the interest of network engineers in recent years. Critical to the design of these systems is an accurate channel propagation model. Given the elementary geometry seen in most tunnels, models which approximate them as a rectangular waveguide have been developed. These models are extremely accurate in vehicular tunnels because - since the tunnel is typically cast from concrete - the cross section is uniform throughout and the surface roughness is negligible. Mines, however, do not conform to these two conditions. In this paper, we propose a simple raytracing model for tunnels with varying cross section and measurable surface roughness. The effectiveness of the proposed model is validated through in-house field measurements collected in a train tunnel and in a coal mine. We show that while the waveguide model performs well in the former, it falters in the latter. The proposed model, however, predicts reliably in the coal mine as well.
Proceedings Title: IEEE 2012 Global Telecommunications Conference
Conference Dates: December 3-7, 2012
Conference Location: Anaheim, CA
Pub Type: Conferences
Mine, surface roughness, convex, concave