Soft handover method for mobile wireless sensor networks based on 6LoWPAN

In many wireless sensor network applications the sensor nodes needs to be mobile. In order to support mobility, the management of several issues, such as routing, handover, security, addressing and auto-configuration of the network needs to be handled. In the past, the main focus of sensor network research has been on static sensor networks, therefore many mobility related problems remain unsolved. In this paper, the focus is on the management of handover and addressing in networks, where gateways and sensor nodes can be mobile. A novel approach, which eliminates unnecessary handovers in the case where multiple gateways are in the range of mobile sensor node, is introduced in this paper. The proposed soft handover method has been implemented and its functionality has been proven in a full-scale testbed. Furthermore, it has been evaluated that the soft handover method performs fairly well also in the sensor network where gateways are static. The proposed solution is designed for IEEE 802.15.4 standard based sensor networks which use 6LoWPAN technique, but it can be easily adapted also to other type of networks.