Visible Light Communication Module: An Open Source Extension to the ns3 Network Simulator with Real System Validation

The emergence of new physical media such as optical wireless and the ability to aggregate these new media with legacy networks motivate the study of heterogeneous network performance, especially with respect to the design of protocols to best exploit the characteristics of each medium. We consider visible light communications (VLC), which is expected to co-exist with legacy and future radio frequency (RF) media. While most of the research on VLC has been done on optimizing the physical medium, research on higher network layers is only beginning to gain attention, requiring new analyses and tools for performance analysis. To meet this need, we have developed a new ns3-based VLC module that can be used to study VLC-RF heterogeneous networks via simulation. The proposed ns3 module has been developed based on existing models for intensity modulated LED signals operating as lighting units transmitting to optical receivers at indoor scales (meters). These models and the corresponding simulation model are validated using a test bed implemented with a software-defined radio system, photo detector, phosphor-converted 'white' LEDs, and under PSK and QAM modulation. Two scenarios are used in the validation of the VLC module: 1) using a receiver placed normal to the transmitter with varying range; and 2) using a receiver with a fixed range with varying angle of acceptance. Results indicate good correspondence between the simulated and actual test bed performance. Subsequently, we demonstrate how the VLC module can be used to predict the performance of a hybrid Wi-Fi/VLC network simulated using the ns3 environment with UDP, TCP, and combined network traffic.