Accuracy Analysis of the Geometrical Approximation of MIMO Channels Using Ray-Tracing

Channel characterization is one of the most important steps in the design and performance evaluation of a communication system. With the adoption of larger antenna arrays (up to the hundreds, in massive MIMO systems) and millimeter waves, measurement campaigns require expensive equipment to be performed. An alternative approach is to use ray-tracing techniques to accurately obtain MIMO channel responses. For time-varying scenarios, the simulation can be very computationally expensive. An alternative method is to obtain SISO channel responses, and then use the geometric channel model to generate the full MIMO channel for uniform linear or planar antenna arrays. This works analyses the impact of this approximation in the estimated channel capacity and NMSE (normalized mean square error).