WEAR: A Balanced, Fault-Tolerant, Energy-Aware Routing Protocol for Wireless Sensor Networks

1. WEAR: A Balanced, Fault-Tolerant, Energy-Aware Routing Protocolfor Wireless Sensor Networks Kewei Sha, Junzhao Du, and Weisong Shi Wayne State University International Journal of Sensor Networks2006

2. Outline • Introduction • WEAR: A Weighted Energy-Aware Routing Protocol • Hole information calculation • Weight definition and calculation • Simulation • Conclusion

3. Introduction • Four general requirements of any routing protocol • Energy efficient • Find a shortest path • Load balanced • Remaining energy • Fault tolerant • Bypass the hole • Prevent the hole enlarging • Scalable • Use localized information

4. Introduction • GPSR(RHR) Hole source Destination

5. Introduction • Hole enlargement using GPSR Hole source Destination

6. Motivations and Goals • Motivations • Identify and maintain the hole information • Take energy-efficiency, load balance, fault tolerance , and scalability into consideration • Goals • Extend network lifetime • Sensors avoid to route message towards the hole • Distribute the load to the alternative paths

7. Assumptions • Sensors have location information • Sensors is stationary and the sink is fixed • Holes in a rectangle shape

8. WEAR --- routing modes • Weight contains four factors • Distance to the destination • Remaining energy of a sensor • Local hole information • Global location information

9. WEAR --- routing modes • Greedy mode • Current sensor forwards the message to the neighbor having the smallest weight value • Bypassing mode • The routing follows the right-hand rule

10. WEAR --- overview Weight of energy Weight of hole

11. WEAR --- Hole information calculation • To bypass the hole and prevent the hole enlargement • Hole identification • Hole locating • Hole announcing • Hole propagating • Hole maintenance

12. WEAR --- Hole locating • Calculate the of the hole • Collect the minimum and maximum x-y coordinators of hole boundary and maximum ID of sensors • Use “Locating and bypassing routing holes in sensor networks”

13. WEAR --- Hole announcing • The hole information is distributed to sensors on the hole boundary • Sensors have complete hole information

14. WEAR --- Hole propagating • Hole edge sensors broadcast hole information to sensors within preset maximum hops

15. WEAR --- Hole maintenance • Hole may enlarge or change shape • Holes in a sensor field will change in two styles • Hole enlargement • Hole mergence • Hole maintenance • Periodical maintenance • Reactive maintenance

16. WEAR --- Hole enlargement • Failed sensors on the boundary of the hole Node N is a new stuck node and it starts a hole identification process

17. WEAR --- Hole mergence • Some sensors located on the edge of the two or more holes Node B recognize a hole mergence B combines the two hole ID , like ID(h1, h2)

18. WEAR ---Weight calculation Global location information Remaining energy Local hole information Distance to the destination ,, and

19. WEAR --- Weight calculation • The Global location information • The nearer to the sink, the more important the sensor • In simulation, α= -1 • The local hole information • In simulation, β= 2

20. WEAR --- Weight calculation • The remaining energy • In simulation, γ= -1 • The distance to the destination • Geometric distance between the jth sensor and the destination • In simulation = 6

21. Simulation • Simulator: Capricorn • Communication Range:30m • Number of node: 2012 • Sensing area: 1000 x 1000 m2 • Sink sends a query message • Destination sends a replymessage sink

22. Simulation EC=Ec/E0 GPSR WEAR GEAR

23. Simulation Network partitions or More than 5% sensors fail Sensor network lifetime

24. Simulation Comparison of the number of failed sensor

25. Simulation Comparison of the path length extension rate

26. Simulation Hole extension

27. Conclusion • Proposed a load balanced , fault tolerant ,energy-efficient routing protocol • Extend the lifetime of the sensor network • Control the number of the failed sensor and hole enlargement