What is Threshold Breakdown Problem

One of the severe security threats in wireless sensor network is false data injection attack, that is, the compromised sensors forge the events that do not occur. To defend against false data injection attack, six en-route filtering schemes in a homogeneous sensor network are described. Furthermore, one sink filtering scheme in a heterogeneous sensor network is also presented. We find that deploying heterogeneous nodes in a sensor network is an attractive approach because of its potential to increase network lifetime, reliability, and resiliency.