A comparison of 3D computer propagation prediction with GSM signal measurements

This paper presents comparisons between predicted and measured data for a live GSM system. Our propagation prediction software tool is based on 3D-ray tracing, and considers wave interactions, such as free space, reflection, diffraction, and scattering. The underlying principles used in the prediction tool are geometric theory of diffraction (GTD), with its uniform theory of diffraction (UTD) extension and physical optics to provide signal levels and delay spread information. We have performed GSM measurements in a number of chosen streets in London. The measurement results are analysed in terms of a number of GSM system parameters, which include RXLEV, RXQUAL, and handover characteristics. A 3D representation of the measurement environment was modelled in the software tool using a building database to verify the computer prediction and to show that 3D prediction is viable for small urban cells with excellent accuracy and speed.