FaLQE: Fluctuation Adaptive Link Quality Estimator for Wireless Sensor Networks

Accurate link quality estimation is a prerequisite for efficient routing in wireless sensor networks. Good link quality estimators should provide agility and stability simultaneously, which not only filter out transient link quality fluctuations but also respond quickly when sudden changes arise. However, only stability or agility is considered as optimization goal in existing estimators, so their performance is always below expectations. In this paper, a fluctuation adaptive link quality estimator is proposed, which adjusts smoothing factor of the estimation dynamically according to the degree of link quality fluctuations and achieves equilibrium of stability and agility. Experimental results show that stability of the proposed estimator is same as that of existing stable estimators when there are transient fluctuations, and agility of the proposed estimator is same as that of existing agile estimators when sudden changes arise. More importantly, compared with existing estimators, the estimate error of the proposed one is reduced by 22.5%–31.8% for different link characteristics.