Refinement of an emulator for the physical layer of the wireless communication of sensor networks

Abstract: Wireless sensor networks have applications in many different fields and environments, each with their own set of challenges to be overcome. If we can measure and compensate for the properties of the wireless environment at an early stage of the deployment, we will be able to have the sensor network operational in a smaller time frame. This report describes the development of an emulator for wireless sensor network of up to eight 802.15.4 complaint sensor nodes. The FPGA-based emulator has been enhanced with several new features to remove some shortcomings of the existing emulator. The emulator now provides the ability to import previously recorded data representing time varying gains of wireless links, the ability to store the signal data generated by the sensor node for later review, as well as a more intuitive user interface to make the emulator more useful as a research tool. A latency issue that previously prevented the use of any communications protocol depending of transmission acknowledgments has been studied and a solution to the issue is presented. A way of introducing external interference to the emulated system has also been investigated and provides a straightforward way of introducing interference to the system without modifying the existing hardware and software. Most added features have been designed to be easily modified or expanded upon.