Channel model implementation for evaluation of location services

Simulation and evaluation of location services presents a number of new problems in the area of stochastic channel modelling which conventional models do not account for. Such problems are modelling of line of sight (LOS) probabilities, LOS to non-line of sight (NLOS) power ratios, NLOS excess propagation time delay, out of cell radio propagation/coverage, and spatial correlation factors. A two level channel model which addresses these problems is introduced. Local level effects, based on the CODIT propagation model, and cell level effects are incorporated. LOS probabilities and shadowing effects are treated independently at each level. Several scenarios are developed to model different levels of radiowave propagation between cells, corresponding to flat and hilly terrain. Simulation results for the two proposed idle period downlink (IDPL) time difference of arrival (TDOA) techniques for UMTS are presented.