Fault tolerance is one of the premier system design desiderata in wireless ad hoc and sensor networks. It is crucial to have a certain level of fault tolerance in most of ad hoc and sensor applications, especially for those used in surveillance, security, and disaster relief. In addition, several network security schemes require the underlying topology provide fault tolerance. In this chapter, we will review various fault tolerant techniques used in topology design for ad hoc and sensor networks, including those for power control, topology control, and sensor coverage.
Key Terms in this Chapter
Fault Tolerance: If a network is fault tolerant or k-fault tolerant it means the network can survive under single or k node/link failures simultaneously.
Self-Protection: A sensor network is p-self-protected, if at any moment, for any wireless sensor (active or nonactive), there are at least p active sensors that can monitor it.
Power Control: Controls the network topology by adjusting the wireless device’s transmission range to minimum energy consumption while maintaining a topology that is connected or has certain desired properties.
Topology Control: Let each wireless device locally select certain neighbors for communication, while maintaining a topology that can support energy efficient routing and improve the overall network performance.
k-Coverage: A sensor network achieves k-coverage if every location is covered by at least k different sensor nodes, that is, every location is within the sensing range of at least k different sensor nodes.
K-Connectivity: If a network (graph) has k-connectivity, it means the it is k-connected, that is, given any pair of wireless devices (nodes), there are at least k disjoint paths to connect them.
Virtual Backbone: A connected backbone formed by a subset of wireless nodes selected to perform communication tasks for the other nodes and the whole network.