Comparison of ITM and ITWOM propagation models for DVB-T coverage prediction

Digital broadcasting services require higher prediction accuracy than traditional analogue networks because digital services are planned with tighter margins on the received signal strength and interference. With the rapid deployment of digital TV, there is an increasing need for accurate point-to-area prediction tools. There are several propagation models for coverage prediction of DVB-T. Some of them are purely empirical models, and others are mixed, empirical-analytical models, based on measurements campaigns and electromagnetic theory. The aim of this paper is to compare precision field-strength measurements taken by a Rohde & Schwarz FSH-3 portable spectrum analyzer with simulation results derived from coverage prediction models, like the NTIA-ITS Longley-Rice model, the ITM (Irregular Terrain Model) using the 3-arc-second SRTM (Satellite Radar Topography Mission) data that is available freely, and the newly developed ITWOM (Irregular Terrain with Obstructions Model).