Diffraction loss prediction for land mobile radio communication

It is well known in land mobile communications that almost 95% of the radio links between the transmitter and receiver is non-line-of-sight. The diffraction loss plays a major role in the total propagation loss prediction. Hence, this paper examines and improves the diffraction loss predication in two main aspects. First, the diffraction loss is calculated based on the multiple bridged knife edge model proposed by J.H. Whitteker (see Radio Science, vol.28, no.4, p.487-500, 1993). Secondly, a higher resolution and more accurate digital terrain database is investigated by using various interpolation techniques. To cope with a huge amount of terrain data, a spatial database structure called a quadtree is also introduced