Knowledge of propagation behavior of radio waves is a fundamental prerequisite for planning and optimizing mobile radio networks. Propagation effects are usually simulated numerically since real-world measurement campaigns are time-consuming and expensive. Automatic planning algorithms can explore a vast amount of network configurations to find good deployment schemes. However, complex urban scenarios demand for a great emphasis on site-specific details in the propagation environment which are often not covered by automatic approaches. Therefore, we have combined the simulation of radio waves with an interactive exploration and modification of the propagation environment in a virtual reality prototype application. By coupling real-time simulation and manipulation tasks, we can provide an uninterrupted user-centered workflow.
Ray tracing approaches are an established technique for radio wave propagation simulations, however, such approaches need to be extended to include diffraction, which is a predominant effect of common mobile radio frequencies. Diffraction along edges is usually modeled by shooting a multitude of rays into the shadow cone of the diffracting edge, which usually results in a large computational overhead. The parallel computing capabilities of recent Graphics Processing Units (GPUs) can help to address this issue.
The key idea of implementing diffraction on the GPU is to utilize the concept of shadow volumes to directly render diffraction cones. Only those propagation paths which pass through a certain height level above ground where cell phone reception is required are of interest for radio wave propagation predictions. By applying a modified shadow volume technique, all pixels that are inside a diffraction cone are identified on the image plane, which is setup to correspond to the receiver plane. Thereby, the GPU implementation reduces the problem of finding diffraction rays to repeated shadow computations, which can be done extremely fast on recent GPUs.Videos
Virtual Reality Interface
- A Virtual Reality System for the Simulation and Manipulation of Wireless Communication Networks
- Efficient Rasterization for Outdoor Radio Wave Propagation
- Beam Tracing for Multipath Propagation in Urban Environments
- Simulation of Radio Wave Propagation by Beam Tracing
- Fast Edge-Diffraction-Based Radio Wave Propagation Model for Graphics Hardware
- Accelerating Radio Wave Propagation Predictions by Implementation on Graphics Hardware