SimX: An Integrated Sensor Network Simulation and Evaluation Environment

It is well known that designing, testing and debugging sensor networks are extremely hard. It is mainly due to limited resources and distributed natures of sensor networks. In a lab environment, it is difficult and tedious to try various network configurations and simulate various challenging environment factors. Thereafter, the sensor network community has longed for a good sensor network simulation tool allowing the philosophy of WYSIWYG: What You See Is What You Get. In this paper, we present the design and evaluation of a visualized network manipulation tool integrated with TOSSIM and TOSSIM Live, called SimX. The SimX includes the following features: (1) topology manipulation, which allows a simple mouse drag on the virtual network node to actually change the physical network topology and the link qualities; (2) timing control, which allows a user to control a simulation to run faster or slower, even to pause the simulation; (3) variable watch and conditional breakpoints, which allow a user to watch variable value changes of all network nodes concurrently and set conditional breakpoints; (4) sensor input control, which allows a user to simulate different sensor data inputs and sampling rates. Besides supporting those traditional evaluation criteria, such as throughput, energy efficiency and delivery ratio, the SimX also supports a holistic evaluation methodology. The holistic evaluation methodology evaluates how well the holistic high-level spatial and temporal environmental changes have been recorded, not only those lowlevel engineering criteria. We also designed a XML-based sensor network visualization tool, which allows the user to illustrate any sensor network data, including data imported from TOSSIM and SimX. keyword: Wireless Sensor Network, Simulation, SimX, TOSSIM, XMonitor