Anchor-based void detouring routing protocol in three dimensional IoT networks.

In recent years, several applications of Internet of Things (IoT) have been observed in various areas including environmental monitoring, healthcare systems, cognitive smart agriculture, industrial control, smart homes, intelligent transportation systems, and traffic management. For such applications, wireless sensor networks (WSNs) are generally deployed to gather the sensed data from the targeted application field. In order to transfer the sensor node data to the gateway (sink node), novel routing protocols need to be developed, leading to reduced data transmission delay, high data throughput, and improved energy efficiency across the network. In this context, geographical routing protocol has been considered as a promising approach for the path selection in WSNs. This approach is full of scalability and multi-hop routing is performed using local decisions. However, geographical routing protocols suffer from the void node problem (VNP) i.e., a region where active nodes are not available in the direction closer to the destination. Numerous protocols have been designed to get recovery from VNP in 2D networks which cannot be directly applied to 3D networks. The 3D routing includes the networks deployed in the hilly area, high buildings, airborne region, underground, underwater and so forth. On applying the 2D routing protocols on complex 3D topology, the network may face additional problems like packet looping, routing failure, ambiguity, or increased data latency due to longer path. Further, the majority of geographical routing protocols follow the boundary of void which leads to a longer path. In order to address the aforementioned challenges, this paper presents a novel anchor-based void detouring routing (AVDR) protocol where anchor node is treated as a sub-destination which provides the direct smaller path between source and gateway nodes. The proposed method bypasses the void boundaries and directly connects source to anchor, anchor to destination, or two successive anchors. Further, anchor information is distributed to the desired region to reduce the periodic anchor advertisement process. The effectiveness of the proposed method has been tested over both, real field data set and simulated testbed with OMNET++ simulator. The results obtained over real field data set claim that the proposed method takes only 29.09 ms (ms) for transferring the data on an average. However, this value is 32.37 ms, 34.32 ms, 33.61 ms, 37.20 ms, and 38.73 ms, respectively, using A3DR, EDGR, GPSR-3D, BSMH, and RPL methods. Moreover, it is also noted that the proposed method achieves an improvement of 8.2%, 7.54%, 7.66%, 8.49%, and 8.22%, in routing stretch when compared to aforementioned methods, respectively. This improvement with respect to network overhead is 30.25%, 57.45%, 51.05%, 75.56%, and 58.89% using the proposed method.