Experimental study of hierarchical Software Defined Radio controlled Wireless Sensor Network

In this paper, we examine an hierarchical Software-Defined Radio (SDR) controlled Wireless Sensor Network (WSN) testbed built in our Wireless Communications Lab. In this testbed, an hierarchical cluster-based topology is employed to fulfill the needs of energy efficiency and scalability where a group of XBOW MicaZ Sensors/Motes in communication with a Universal Software Radio Peripheral (USRP2) forms a cluster. The USRP2s act as cluster heads to perform data collection using the least interfered channels due to their capability in channel sensing and waveform selection. The USRP2 also serves to extend the transmission range of the sensors and eliminates the excessive overhead required in ad hoc WSN cluster heads. The cluster heads receive the data transmission from the motes on multiple channels and relay the data to the central control on a separate channel. It is expected that this testbed would help the research community in understanding and gathering insightful knowledge about SDR controlled WSNs in a practical context.