The effects of building geometric displacement error on urban microcellular ray based modelling

The effects of building geometric placement error have been considered both theoretically and using a two dimensional ray based model. The ray based model implements both reflection and diffraction and operates on a uniform, 1 km square grid of building data. Placement error is modelled by randomly displacing the building coordinates using a truncated Gaussian distribution. It has been found both theoretically and verified with results from a computer testbed that, when reflection predominates, the effect of angular error (rather than spatial error) is most significant as this causes rays to deviate away from their true route. It has been found that close to the transmitter, with an RMS deviation of 2.0 m in the building vertex position, that path loss peaks, caused by reflection, and corresponding path loss “nulls” can be moved up to 50 m