Communication protocols for WSANs

This chapter focuses on the important issues for the design of WSANs such as those related to routing, localization, and time synchronization and signal processing. Classic MAC and routing protocols studied for wireless voice and data traditional networks are not suitable for wireless sensor networks. Many specific aspects that differentiate them from the traditional communication networks in fact characterize wireless sensor networks. First, nodes are based on battery supply and a typical applications environment does not allow to simply changing batteries. Second, often nodes are deployed in an ad hoc way rather than with careful pre-planning; they must then organize themselves to create a communication network. Third, sensor networks are generally composed by a high number of nodes; furthermore, node density can vary in different places, having both sparse areas and other areas with nodes with many neighbors, and it can also vary during time. Finally, sensing events generates most traffic in the network, and it can be extremely bursty. MAC and routing protocols for wireless sensor networks have therefore to face each of the mentioned issues. Energy efficiency is one of the most important goals to achieve in designing protocols for wireless sensor networks. To do that, the protocols should address the major sources of energy waste on MAC and routing levels.