Ferry-based linear wireless sensor networks

Many environmental, commercial, military, and structural monitoring applications of wireless sensor networks (WSNs) involve lining up the sensors in a linear form, and making a special class of these networks; we defined these in a previous paper as Linear Sensor Networks (LSNs), and provided a classification of the different types of LSNs. A multihop approach to routing the data from the individual sensor nodes to the sink can be used in an LSN. However, this can result in a rapid depletion of the sensor energy, due to the frequent transmissions performed by the sensors to transmit their own, as well as other sensor data. In addition, in many applications, the distance between the sensors deployed to monitor the linear structure might be much greater than the communication range leading to a disconnected network where the multihop approach cannot be used. This paper presents a framework for monitoring linear infrastructures using ferry-based LSNs (FLSNs). The data that is collected by the sensors is assumed to be delay-tolerant. In such a system, a moving robot, vehicle, or any other mobile node (named a ferry), can move back and forth along the linear network, and collect data from the individual sensors when it comes within their communication range; The ferry can deliver the collected sensor data when it reaches the sink. It can also perform other functions, such as data processing, and aggregation, and can also transport messages from the sink to the sensor nodes (SNs). Four different ferry movement approaches are presented, simulated, and analyzed.