Sensei-UU: A Nomadic Sensor Network Testbed Supporting Mobile Nodes

We present Sensei a nomadic, or relocatable, wireless sensor network (WSN) testbed with support for mobile nodes. The nomadism makes it possible to evaluate a WSN application in different environments ranging from lab environment to in-situ installations to prototype deployments. Other WSN testbeds are often static and can not be easily moved between sites. To be easily relocateable and highly flexible, Sensei uses a wireless 802.11 b/g network as control channel. Our design with a wireless control channel allows easy incorporation of mobile nodes. Since sensor nodes often use 802.15.4 (ZigBee) communication, we have investigated the interference between the control channel and a 802.15.4 WSN to ensure that this approach is a feasible approach. For repeatability in terms of mobility, nodes can be carried either by humans or robots following mobility scripts. We present a method for localization of mobile nodes based on robot technology. The robots use laser range finders for localization and navigate in a predefined map. We evaluate the precision of this method in an office like environment to ensure sufficient repeatability of mobility experiments.