Accurate high-speed urban field strength predictions using a new hybrid statistical/deterministic modelling technique

To effectively dimension and rollout a cellular network, accurate sitespecific field strength predictions are required. Traditionally, operators make use of high-speed statistical propagation models for each proposed base site. Today’s advanced cellular networks place a greater emphasis on urban microcellular deployment. It is well known that statistical models perform poorly in such environments. To overcome these limitations, the use of deterministic propagation modelling is common. However, although such models enhance prediction accuracy, they also require excessive computation time. In this paper a new hybrid statistical/deterministic field strength prediction model is proposed that combines the speed of a statistical model with the site-specific accuracy of a deterministic ray model. Results indicate that the new hybrid model can produce very accurate field strength prediction grids with computing times reduced by one to two orders of magnitude. For the example considered in this paper, the computing time for a one square kilometer grid comprising 10,000 points (100 by 100) has been reduced from 20 mins to just over 4 minutes (running on an 800MHz Pentium III). For more complex ray models and/or higher grid densities, even higher speed-up factors can be achieved.