Energy Constraints of Localization Techniques in Wireless Sensor Networks (WSN): A Survey <s> Approximate Point in Triangulation (APIT) <s> This book presents an in-depth study on recent advances and research in Wireless Sensor Networks (WSNs). Existing WSN applications are described, followed by discussing the ongoing research efforts on some WSNs applications that show the usefulness of sensor networks. Theoretical analysis and factors influencing protocol design are highlighted. The state-of-the-art protocol for WSN protocol stack is explored for transport, routing, data link and physical layers. Moreover, the open research issues are discussed for each of the protocol layers. Furthermore, the synchronization and localization problems in WSNs are investigated along with the existing solutions and open research issues. Finally, the existing evaluation approaches for WSNs including physical testbeds and software simulation environments are overviewed. <s> BIB001 </s> Energy Constraints of Localization Techniques in Wireless Sensor Networks (WSN): A Survey <s> Approximate Point in Triangulation (APIT) <s> 1. Introduction 2. Network deployment 3. Localization 4. Time synchronization 5. Wireless characteristics 6. Medium access and sleep scheduling 7. Sleep-based topology control 8. Energy-efficient and robust routing 9. Data-Centric networking 10. Transport reliability and congestion control 11. Conclusions. <s> BIB002
An approach similar to localization using geometric constraint is the approximate point-in-triangulation (APIT) technique. APIT is similar to geometric constraint localization method in that it provides location estimate as the centroid of an intersection of regions. The novelty in the implementation of this technique lies in how the regions are defined. Triangles between different sets of three reference nodes (rather than the coverage of a single node) are used in the localization procedure. APIT employs local area approach, where anchor nodes demarcate the network of nodes into triangular regions. A node's presence inside or outside of these triangular regions allows a node to narrow its area in which it can potentially reside. It is usually very difficult to locate unknown nodes lying within the triangle formed by three reference nodes if the nodes are stationary since wireless signal propagation is usually not ideal. An approximate solution can be determined using some prior location information, that is, the ability to determine which of two nodes is nearer a third node based on the signal reception. One limitation for the APIT technique is that it can provide inherent erroneous results, because the determination of whether a node lies within a particular triangle requires quite a high deployment of anchor nodes in order to provide good localization accuracy BIB002 . This technique depends on anchor nodes but has the advantage of no extra hardware. Localization error of 0.4R is acceptable, where R is the range of the anchor nodes BIB001 .