Ray Tracing Channel Modeling for Optical Wireless Networks On-Chip

Optical Wireless Networks on Chip have become an ambitious but attractive solution to increase computing performances in multi-core/multi-chip architectures. To assess the benefit of the wireless optical solution a truthful characterization of the wireless channel at the chip scale has to be carried out. Propagation in Optical Wireless Network on Chip occurs in a layered environment, where the layer thickness is often very small compared to the link distance: a high order of multiple reflections/refraction bounces is therefore necessary, triggering strong multipath effect. In this paper the reliability of an 'ad hoc' Ray Tracing tool, developed for the specific on chip environment, is described and tested with measurements. Prediction of the average path gain range dependence is quite reliable, whereas fast fading tracking accuracy is hampered by unavoidable imprecision in the digital description of the antennas and/or of the propagation environment.