1. 1 Multipath Routing in WSN with multiple Sink nodes YUEQUAN CHEN, Edward Chan and Song Han Department of Computer Science City University of HongKong

2. 2 Outline Issues of energy consumption in WSN Architecture of Multiple Sink Main Idea in MRMS MRMS protocol description Experimental Results

3. 3 Issue in Energy Consumption of WSN Sensors near the sink nodes will dissipate energy faster than other sensors How to scale the network size Solution: Deploying multiple Sink nodes in WSN is one of best choice.

4. 4 Architecture of Multiple Sink Nodes

5. 5 Main Idea in MRMS Topology Discovery –Three-color algorithm –Based on path cost

6. 6 Main Idea in MRMS (cont) Cluster Maintenance –Energy monitoring –Cluster reconstruction Path Switching –Patch Switching based on path cost

7. 7 MRMS protocol description － Topology Discovery Before Topology Discovery After Topology Discovery

8. 8 Topology Discovery Topology Discovery is based on three-color algorithm The cluster is stateless The metric of constructing the cluster is based on path_cost using Dijstra algorithm

9. 9 MRMS protocol description － Intra-Cluster Reconstruction (a) Broadcast SELECT_NEW_CH (b) Select Maximum Residual Energy node

10. 10 MRMS protocol description － Intra-Cluster Reconstruction (c) Broadcast NEW_CH (d) New Cluster after re- construction

11. 11 MRMS protocol description － Inter-Cluster Reconstruction (a) Before change delivery node (b) After change delivery node

12. 12 Cluster Reconstruction Cluster Header monitors its energy periodically In the intra-cluster reconstructing, select the max residual energy as new cluster head In the inter-cluster reconstructing, select the node whose path_cost to sink is min as new delivery node.

13. 13 MRMS protocol description － Path Switching (a) Before path switching (b) After path switching

14. 14 Path Switching Using event-based approach to trigger the path switching, not periodical update approach Select the min path_cost to other sink node as new path.

15. 15 Experimental Results Time to First Node Failure

16. 16 Experimental Results Number of Dead Nodes

17. 17 Experimental Results Average Energy Consumption for packet

18. 18 Experimental Results Average Hop Count vs Time

19. 19 Experimental Results Average Distance to Sink vs Time

20. 20 Experimental Results Packet Delivery Ratio

21. 21 Contributions New path cost metric Stateless clusters Path switching

22. 22 Thanks Any Questions?