We present the state-of-the-art related to self-organizing and self-healing techniques. On the one hand, self-organization is the nodes’ ability to construct a network topology without any human intervention and any previous topology knowledge. On the other hand, self-healing is the network’s ability to recover from failures by using hardware and software redundancies. By using both techniques, Wireless Sensor Networks (WSNs) can be deployed in unattended and harsh environments where on-site technical service is unfeasible. In the last few years, a large amount of work has been done in these two research areas, but these different techniques occur at different layers and with no general classification or effort to consolidate them. One of the contributions of this paper is the consolidation of the most significant and relevant mechanisms in these two areas, and additionally, we made an effort to organize and classify them. In this review, we explain in detail the two stages of self-organization, namely topology construction and management. Moreover, we present a comprehensive study of the four steps in a self-healing technique, namely, information collection, fault detection, fault classification and fault recovery. By introducing relevant work, comparative tables, and future trends, we provide the reader with a complete picture of the state-of-the-art. Another contribution is the proposal of a unified framework that employs self-organizing and self-healing mechanisms to achieve a fault-tolerant network.
The State of the Art in Cross-Layer Design for Wireless Sensor Networks
