Reliability in Wireless Sensor Networks: Survey and Challenges Ahead

This paper presents a survey on existing data transport reliability protocols in wireless sensor networks (WSNs). Most of the existing research employs retransmission mechanisms to achieve reliability, ignoring the use of redundancy schemes such as erasure codes to enhance event reliability. We review the data transport reliability schemes in terms of event and packet reliability using retransmission or redundancy mechanisms. Furthermore, we analyse and compare the existing data transport reliability protocols based on several attributes, specially the importance of event reliability over packet reliability through the use of retransmissions or redundancy. On the basis of the analysis, we finally point out some future research directions and challenges ahead in order to enhance reliability in WSNs.