WEAR: A Balanced, Fault-Tolerant, Energy-Aware Routing Protocol for Wireless Sensor Networks Kewei Sha, Junzhao Du, and Weisong Shi Wayne State University International Journal of Sensor Networks 2006

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

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

Introduction source Destination GPSR(RHR) GPSR(RHR) Hole

Introduction source Destination Hole enlargement using GPSR Hole enlargement using GPSR Hole

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

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

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

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

WEAR --- overview Weight of hole Weight of energy

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

WEAR --- Hole locating Calculate the of the hole Calculate the of the hole Collect the minimum and maximum x-y coordinators of hole boundary and maximum ID of sensors 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 ”

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

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

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

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

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)

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

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

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

Simulation Simulator: Capricorn Communication Range:30m Number of node: 2012 Sensing area: 1000 x 1000 m 2 Sink sends a query message Destination sends a reply message sink

Simulation GPSR GEAR WEAR EC=E c /E 0

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

Simulation Comparison of the number of failed sensor

Simulation Comparison of the path length extension rate

Simulation Hole extension

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