Energy Constraints of Localization Techniques in Wireless Sensor Networks (WSN): A Survey <s> Binary Proximity <s> A novel system for the location of people in an office environment is described. Members of staff wear badges that transmit signals providing information about their location to a centralized location service, through a network of sensors. The paper also examines alternative location techniques, system design issues and applications, particularly relating to telephone call routing. Location systems raise concerns about the privacy of an individual and these issues are also addressed. <s> BIB001 </s> Energy Constraints of Localization Techniques in Wireless Sensor Networks (WSN): A Survey <s> Binary Proximity <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
This is a very basic location technique, binary proximity involves a simple decision of whether some sensor nodes are within the reception range of each other or not. This technique usually employs some anchor nodes as reference for locating unknown nodes in the network. These anchor nodes usually transmit beacon signals which the unknown nodes use to estimate their position in the network. Alternatively, unknown nodes will transmit beacon signals as and when it needs to be localized. This technique is most like to be efficient for clustering in a large scale network. An excellent example of proximity detection as a means for localization is the Active Badge location system meant for an indoor office environment BIB001 . A much larger application of localization, using binary proximity detection, is with passive radio frequency identification (RFID) tags. RFIDs are employed for animal tracking and environmental monitoring. A key difference in RFID proximity detection compared with active badge is that the unknown nodes are passive tags being queried by reference nodes in the sensor network BIB002 . No extra hardware is required in this technique but relies heavily on anchor nodes for accuracy in clear line-of-sight and RF (signal) coverage which may pose challenges for some applications.