SDN-(UAV)ISE: Applying Software Defined Networking to Wireless Sensor Networks with Data Mules

In this paper, a software defined networking approach, named SDN-(UAV)ISE, is introduced for wireless sensor networks with data mules. In our scenario, sensor nodes are equipped with two wireless interfaces: one exploits a long range, low data rate wireless technology, such as LoRa or Sigfox, whereas the other uses a short range, wireless technology that provides higher data rate, examples include IEEE 802.15 or IEEE 802.11. Sensors can communicate directly to a control center through the long range wireless interface, or by utilizing the multihop paradigm realized with the aid of the short range wireless communication interface. In this context, a drone acts as a mobile sink (i.e., the mule) for the latter case. The movement of the data mule is forecast by the SDN controller and the forecast positions are considered to generate the flow table entries to be installed in the sensor nodes and schedule their applications. To this purpose, it is expected that the drone will move to the locations where abnormal conditions are observed by the sensors. In our work, a simple and efficient decision tree algorithm is implemented, which takes the values measured by the sensors as inputs, to forecast the route of the data mule. The proposed scheme is assessed through a large experimental campaign considering different operating conditions.