SNUPI: Sensor Network Utilizing Powerline Infrastructure

Abstract

Over the past few decades, wireless sensor networks have transformed the way in which we collect information about the world around us. The low cost of the sensor nodes and the simplicity of installation make wireless sensor networks highly scalable, and therefore they are able to obtain rich sets of sensor data over a wide area at relatively low cost. As a result, wireless sensor networks have been widely deployed for a number of sensing applications including environmental, health, home, commercial, industrial, and military applications. Despite the success of many wireless sensor networks, their usage is often severely con- strained by limited battery life and the maintenance burden of frequently changing batteries. This limitation arises from a well-known trade-off between the lifetime of a sensor node and its wireless range. As the communication power is reduced to improve the lifetime, the wireless range of the node is also reduced. This dissertation describes an indoor wireless sensor network called SNUPI (Sensor Network Utilizing Powerline Infrastructure) that overcomes the traditional power/range trade-off by leveraging the existing power line infrastructure in buildings. In this new wireless sensor network, a single base station receiver is connected directly to the power line (i.e., plugged into an outlet). Each node in the sensor network transmits wireless signals that couple to nearby power lines, thus creating signals that travel through the power line infrastructure to the base station receiver. In this way, the sensor nodes can transmit at much lower power because the signals do not need to propagate over-the-air for the entire path to the base station receiver; they only need to propagate to the nearest power line. In this dissertation, I build upon earlier work using the power line as a receiving antenna for communications, to explore the details required to make such a wireless sensor network both practical and robust. I explore this new power line coupled wireless communications channel and investigate the designs and application-specific optimizations of each element of the sensor network, including the communications protocol, the sensor node, and the base station receiver.