Reliability modeling of wireless sensors

The accuracy of system reliability analysis depends on realistic estimation of failure parameters at the component-level. This paper models the reliability of wireless sensor nodes under three different scenarios, contributing toward reliability analysis of wireless sensor network systems. Under Scenario 1, a sensor node is kept activated and consumes constant energy throughout its lifetime. Under Scenario 2, a sensor node alternates between two modes: sleep mode and active mode. The duration of each mode is fixed. It consumes less power during the sleep mode than during the active mode. Under Scenario 3, a sensor node also alternates between sleep and active modes but the duration of each mode is not fixed. In particular, the duration of the active mode is bounded and follows a certain distribution. However, the time to activate the sensor node is fixed. Numerical example results show that sensor node working under Scenario 3 is the most reliable and offers longest lifetime among the three scenarios while Scenario 1 is the least reliable one.