  We present a novel algorithm that enhances the accuracy of electromagnetic
field simulations in indoor environments by incorporating the Uniform
Geometrical Theory of Diffraction (UTD) for surface diffraction. This
additional diffraction phenomenology is important for the design of modern
wireless systems and allows us to capture the effects of more complex scene
geometries. Central to our methodology is the Dynamic Coherence-Based EM Ray
Tracing Simulator (DCEM), and we augment that formulation with smooth surface
UTD and present techniques to efficiently compute the ray paths. We validate
our additions by comparing them to analytical solutions of a sphere, method of
moments solutions from FEKO, and ray-traced indoor scenes from WinProp. Our
algorithm improves shadow region predicted powers by about 5dB compared to our
previous work, and captures nuanced field effects beyond shadow boundaries. We
highlight the performance on different indoor scenes and observe 60% faster
computation time over WinProp.
