Wireless sensor networks (WSNs) are an emerging technology which can be used for outdoor environmental monitoring. This paper presents challenges that arose from the development and deployment of a WSN for environmental monitoring as well as network performance analysis of this network. Different components in our sensor network architecture are presented like the physical nodes, the sensor node code, and two messaging protocols; one for collecting sensor and network values and the other for sensor node commands. An information model for sensor nodes to support plug-and-play capabilities in sensor networks is also presented.

Wireless Sensor Network (WSN) systems are deployed to monitor specific phenomena. The design of WSNs is prone to errors and debugging and is very challenging due to the complex interactions of software components in a sensor node. This paper presents a set of UML patterns that can be used as a basis for software design of WSN systems. The UML patterns are used to capture the design components, the application flow, the components' behaviour, and the interaction between the components and the application design. The design patterns for WSNs are justified by applying them to the WSN-RFID application that integrates RFIDs and sensor nodes in order to support authenticated point-to-point communication with a sensor node.