Simulations of battle operations in complex environments have improved in fidelity in recent years. However, current communications simulations are not very realistic because they use simplified Radio Frequency (RF) propagation modeling that lacks advanced phenomenological effects. To address this, IAI has been awarded a contract entitled, “Combined Channel Simulator-Emulator Using Ray Tracing And Radiative Transfer Methods and Hardware Emulation.” An innovative approach for on-the-fly (OTF), physics-based RF propagation modeling that interacts with complex synthetic natural environments like terrain, cultural features, atmosphere and weather will be used for developing more realistic communication systems and radar sensor simulations. An advanced channel simulator will be built by combining an efficient ray-tracing algorithm with radiative transfer methods. The simulations will accurately and rapidly predict channel conditions between arbitrary transmitter-receiver pairs as they move through the complex environment. The proposed software can quickly model outdoor channels, including weather conditions, buildings, forests and complex manmade objects. It can find potential high-order multipath links among hilly terrain and various terrain objects. Wideband hardware emulation of the simulated link characteristics will allow for incorporation of hardware radios in the simulation and interferers, improving fidelity. The channel simulator developed in this project will be incorporated into IAI’s Radio Frequency Network Emulator Simulator Tool (RF-NEST). Commercially, this innovation has applications in the gaming industry and test routines for communications device manufacturers.