Codes for locating objects in sensor networks

Karpovsky, Chakrabarty and Levitin introduced identifying codes, which can be applied, for example, to locating objects in sensor networks. In this paper, the underlying structure is Z² where one sensor can check its neighbours within Euclidean distance r. We construct identifying codes in this network that are robust against some changes in the neighbourhood monitored by each sensor. We give bounds for the smallest density of such an identifying code for general values of r. We also provide infinite families of values r with optimal such codes and study the case of small values of r.