Modeling realism in wireless simulations

This paper presents a ray-tracing technique to model the multi-path fading effect in indoor spaces. Random set P of points on all 2D planes inside a given hypothetical indoor space are chosen. Each p_i ∈ P is considered to be a point from which the transmitted signal reflects just before reaching the receiver. A vector sum of the signals that arrives at the receiver from each point p_i provides the resultant signal at the receiver. The received signal strength (RSS) is then computed as the signal envelope of this signal. This technique provides RSS statistics that are similar to those developed after extensive measurements in multi-path environments. In addition, this technique captures the spatial correlation of signal impairment. For example, path loss computed with this technique shows that co-moving receivers experience correlated signal fades while those moving in different spaces see un-correlated fading. The goal of this work is to implement this, low cost, ray-tracing approach in network simulators for experiments that require a spatial contexts such as path diversity in a mmWave system or for leader selection for data forwarding in a dense Internet of Things deployment and proof-of-concept evaluation of inference algorithms for indoor localization. This technique does not compete with or replace other, more accurate and deterministic ray-tracing techniques that use either brute force or geometric optics combined to obtain site-specific signal-to-space mapping.