1. Sensor Networks Jason Turbyfill 16 February 2005

2. Outline Node and network components Factors in network design Features and tasks of each layer Applications

3. Sensor Nodes Low-cost, low-power, and multifunctional Sensing, data processing, power, and communication components

4. Sensor Network Large number of sensor nodes densely populated inside or nearby target Position or pattern of nodes doesn’t matter Protocols must be self-organizing Protocols must be self-organizingCo-operative

5. Sensor vs. Ad-hoc Wireless Sensor network may have far more, densely deployed nodes Sensor nodes can fail more often Frequently changing topology Broadcast, rather than P2P Limited components No global ID

6. Basic Layout Nodes are scattered in a sensor field Each node collects, processes, and sends data to a sink

7. Design Factors Fault tolerance Scalability Production costs Hardware constraints TopologyEnvironment Transmission media Power consumption

8. Protocol Stack

9. Physical Layer Often uses 915 MHz ISM band Power required to transmit signal depends on node elevation Binary signal modulation is generally most power efficient

10. Data Link Layer MAC for sensor networks Power limitations rule out existing MAC protocols Power limitations rule out existing MAC protocols Self-Organizing Media Access Control for Sensor Networks (SMACS) Self-Organizing Media Access Control for Sensor Networks (SMACS) Eavesdrop and Register Algorithm (EAR) Eavesdrop and Register Algorithm (EAR) CSMA–based CSMA–based Hybrid FDMA/TDMA Hybrid FDMA/TDMA Error Control

11. Network Layer Energy-efficient Routing Maximum PA Maximum PA Minimum Energy Minimum Energy Minimum Hop Minimum Hop Max-min PA Max-min PA Data-centric Routing Attribute based naming and querying Attribute based naming and querying

12. Transport and Application Transport Layer TCP works just fine TCP works just fine Application Layer Largely unexplored Largely unexplored Sensor Management Protocol Sensor Management Protocol Allow user to control basic node tasks

13. Applications Military Disaster relief Disaster relief Inaccessible terrain Inaccessible terrainHealth Monitor patients Monitor patientsIndustry Manage inventory Manage inventory Monitoring product quality Monitoring product quality

14. Sources Akyildiz I., et al. “A survey on sensor networks”. IEEE Commun. Mag. 40 (8) (2002) 102--114. Estrin, D., et al. “Next century challenges: Scalable coordination in sensor networks”. Proc. MOBICOM, 1999, Seattle, 263-270. Rentala, P., et al. “Survey on sensor networks”. http://citeseer.ist.psu.edu/479874.html http://citeseer.ist.psu.edu/479874.html