Wireless Sensor and Actuator Networks: Algorithms and Protocols for Scalable Coordination and Data Communication

2.5 OVERVIEW OF BROADCASTING TECHNIQUES

Broadcasting is one of the fundamental operations in wireless sensor and ad hoc networks. It is used to disseminate a message from a node, also called a source, to all other nodes in the network. In sensor and actuator networks, broadcasting usually comes from a sink or an actuator and it is directed to all of the sensors or all of the actuators in the network. Applications of broadcasting include paging a particular host or sending an alarm signal to all nodes in the network. Broadcasting in wireless sensor networks is normally used to disseminate request information for measurements such as temperature and noise level. Broadcasting is often referred to as flooding when it is employed in protocols to disseminate control messages such as route discovery, route maintenance, topology updating and synchronization. Since both sensor networks and actuator networks can be modeled by UDG, we first consider broadcasting separately in sensor networks or actuator networks. Then later we discuss sensor and actuator network as a single heterogeneous network.

Since the transmission range is restricted in wireless sensor actuator networks (WSANs) due to the limited energy of nodes, it is normally impossible for the source to directly cover all recipients in the network. Thus, many nodes have to act as routers by relaying the broadcasting message to their neighbors. The broadcasting message is propagated hop by hop and ultimately reaches all the nodes in ...