Energy-Efficient and Secure System Architecture for Wireless Sensor Networks

Wireless Sensor Networks (WSN) have emerged as a new information-gathering paradigm based on the collaborative efforts of a large number of self-organized sensing nodes. These networks form the basis for many types of smart environments such as smart hospitals, intelligent battlefields, earthquake response systems, and learning environments. A set of applications, such as biomedicine, hazardous environment exploration, environmental monitoring, military tracking and reconnaissance surveillance, are the key motivations for the recent research efforts in this area. Different from traditional networks, sensor networks do impose a set of new limitations for the protocols designed for this type of networks. Devices in sensor networks have a much smaller memory, constrained energy supply, less process and communication bandwidth. Topologies of the sensor networks are constantly changing due to a high node failure rate, occasional shutdown and abrupt communication interferences. Because of the nature of the applications supported, sensor networks need to be densely deployed and have anywhere from hundred to thousands of sensing devices, which are orders of magnitude larger than traditional ad hoc mobile networks. In addition, energy conservation becomes the center of focus because of the limited battery capacity and the difficulty of recharge in the hostile environment. With fundamental difference between traditional networks and sensor networks, it is not appropriate and probably inefficient to port previous solutions for ad hoc networks into sensor networks with only incremental modifications. For ensuring the functionality of a sensor network, especially in malicious environments, security mechanisms are essential for all sensor networks. However, sensor networks differ from classical (wireless) networks and this consequently makes it harder to secure them. Reasons for this are resource constraints of the sensor nodes, the wireless multi-hop communication, and the possibility of node compromise. Since sensor nodes are often deployed in unattended or even hostile environments and are usually not equipped with tamper-resistant hardware, it is relatively easy to compromise a sensor node. By compromising a sensor node, an adversary gets access to all data stored on the node, such as cryptographic keys. This thesis discusses concepts and mechanisms to cope with energy efficiency and security issues in wireless sensor networks. The contribution of this work is to provide a novel system architecture for WSN which offers interfaces for diverse applications to directly control communication, topology, mobility, security, localization, and energy-saving based on predefined requirements