The Economy of Redundancy in Wireless Multi-Hop Networks

Due to frequent link failures in multi-hop wireless networks, redundancy can be an important feature. For example, when planning the structure of a backhaul mesh network for public access, it is common to introduce redundant nodes in the mesh network. These are called redundant, because they do not increase the network capacity under normal operation, due to the shortest-path metric of the routing protocol. Instead, their sole purpose is to increase the network reliability by providing failover links when a link in the shortest-path fails. This paper shows how to estimate the optimal number of redundant nodes for a given topology. In order to do so, a method to calculate the additional network reliability that results from introducing a redundant node to a given topology is also proposed.