20 RAY-TRACING MODEL FOR INDOOR RADIO PROPAGATION AT MILLIMETER FREQUENCIES, AND THE STUDY OF DIVERSITY TECHNIQUES

A deterministic approach to model radio propagation channels in comple x environments and use the model to study diversity techniques is desc ribed. The simulation is based on geometric optics and uses ray tracin g techniques. The effects of all rectangular obstacles are considered by the model. Both reflection and refraction effects are taken into ac count. Simulation results are presented and the reliability of these r esults is examined by comparing them with those obtained from measurem ents at 60 GHz. Also it is shown that it is possible to minimise the s imulation time of the model by an appropriate choice of cell size. The model is seen to be able to investigate delay spread in an environmen t in considerable detail. The performance of space, frequency and pola risation diversity is investigated by use of the model. The results sh ow that space diversity is better than polarisation or frequency diver sity in the environments examined.