Corner and rooftop diffraction in radiowave propagation prediction tools: a review

Accurate radiowave propagation prediction tools are essential for the optimal design of future mobile telecommunication services. In recent years, ray-optical methods have been gaining in popularity, especially for urban radiowave propagation prediction. One of the key propagation mechanisms incorporated in any ray-tracing technique is diffraction. We present new diffraction coefficients for both solid and hollow dielectric wedges. The theoretical predictions are validated throughout against controlled laboratory measurements. For the solid wedge diffraction problem, we compare our predictions with those obtained using the widely used Luebbers' (1984) solution. It is shown that the latter one is in error as much as 10 dB in shadow regions.