A software defined wireless sensor network

We propose a software-defined wireless sensor network system whose behavior can be redefined even after deployment by the injection of sensor node roles by means of wireless network communications. Two main technologies are used to develop this system, role generation and delivery mechanism, and a reconfigurable wireless sensor network with many reconfigurable sensor nodes. In the role generation and delivery mechanism, a scenario compiler generates roles for sensor nodes based on a user-defined scenario description and then delivers the roles to appropriate nodes. We also propose a reconfigurable sensor node composed of an ultra-low power field programmable gate array (FPGA) and a microcontroller unit (MCU) for altering network behavior. By assigning heavy tasks such as sensor and data processing to the FPGA, overloading of the MCU can be avoided. Using wireless communication, both configuration data for the FPGA and programs to run on the MCU can be injected as roles from outside of the sensor node, enabling easy alteration of sensor node functionality depending on situation and/or application. After introduction of a system overview, a prototype system is described and some experimental results are discussed.