A self-organized Wireless Sensor Network (WSN) for a home-event managed system: Design of a cost efficient 6LoWPAN-USB gateway with RFID security

This Thesis investigates the most appropriate choices from a hardware and software design perspective, trying to find a cost-efficient solution for the implementation of a simple and scalable wireless sensor network. The present work goes through the elements that form part of a constrained network and focuses on the design by analysing several network protocol alternatives, radio transmission mechanisms, different hardware devices and software implementations. The construction of a gateway board that starts and coordinates a sensor network is the main target of the thesis. The gateway is connected externally through a USB interface that can be connected to a computer. Inside the WSN, the sensor nodes are connected to the gateway over IEEE 802.15.4 standard for low-power radio based links. The network is designed to be compliant with the TCP/IP stack by means of 6LoWPAN, an adaptation layer protocol used for comprising IPv6 headers. In addition, a small implementation of CoAP (Constrained Application Protocol) is developed that allows interoperability with the sensor nodes on the application layer level. A security mechanism provides packet encryption and identification of nodes by means of RFID reader connected to the gateway and RFID tags attached to the sensor nodes storing security information.