Architectures for heterogeneous wireless sensor networks

In this paper we justify the need for a common architecture for heterogeneous wireless sensor networks. We briefly review various proposed protocols in sensor networks, aggregate them into different groups, which we classify into different layers of the protocol stack i.e. application, networking, medium access control (MAC) and physical layer hardware. This protocol stack also includes cross-layer entities such as power management and security, because they need to be addressed at all layers of the stack. We introduce the concept of protocol stack tree (PST) that is a subset of protocols in different layers to satisfy a given class of application requirements. For example, a QoS, traffic intensive application and routing protocol would not work well with a MAC layer protocol such as S-MAC, whose primary concern is to save energy. We also propose our own solutions for a set of network layer protocols to be part of the new common sensor network architecture. Our solutions offer a wide and scalable tradeoff space between QoS and energy consumption. Our proposal would lead to flexible protocol stack trees on a compact and robust architecture