1. CS710 IEEE Transactions on vehicular technology 2005 A Distributed Algorithm for the Dead End Problem of Location Based Routing in Sensor Networks Le Zou, Mi Lu, Zixiang Xiong Texas A&M University Shinae Woo November 06, 2008

2. 2015-04-262 PAGER Related Work Evaluation Introduction Conclusion Introduction 2 Routing in Sensor Network Location based routing Sensor node Base station A X B Send data to BS !!

3. 2015-04-263 PAGER Related Work Evaluation Introduction Conclusion Introduction 3 The Dead End Problem Sensor node Base station C D A F B G IH E J No neighbor to send

4. 2015-04-264 PAGER Related Work Evaluation Introduction Conclusion Related Work 4 Previous solutions Memorizing Traffic ◦ Dead end nodes save packets and flooding them to all neighbors ◦ Dead end nodes refuse to receive same packet ◦ Not scalable Using planarized graph ◦ Route messages along boundaries of polygons of the planarized network graph ◦ Longer path with loop

5. 5 PAGER Related Work Evaluation Introduction Conclusion PAGER 5 Network Model R Base station B C X E A D Sensor node (Directional) Broad casting Sensors know BS’s location r Little mobility Sufficient Power 5 10 15 18

6. 6 PAGER Related Work Evaluation Introduction Conclusion PAGER 6 Partial-partition avoiding geographic routing ◦ Dangerous area vs. safe area Sensor node Base station C D A F B G IH E J Shadow area Bright area

7. 7 PAGER Related Work Evaluation Introduction Conclusion PAGER 7 PAGER : 2 Phases Sensor node Base station C D A F B G IH E J 1. Finding dangerous area 2. Set routing path to avoid dangerous area Shadow area Bright area

8. 8 PAGER Related Work Evaluation Introduction Conclusion PAGER 8 The Shadow Spread Phase Sensor node Base station C D A F B G IH E J Concave Node - have no neighbors closer to BS than itself Shadow Node - is closer to BS than non- shadow neighbors Bright Node - Non-shadow nodes Border Node - has shadow nodes as neighbor Concave node Shadow node Bright area Border node Shadow area Time Complexity O(nB) n : number of sensor nodes B : beacon broadcast interval

9. 9 PAGER Related Work Evaluation Introduction Conclusion PAGER 9 Partial-partition using shadow spread

10. 10 PAGER Related Work Evaluation Introduction Conclusion PAGER 10 The Cost Spread Phase Sensor node Base station 19 20 16 20 18 15 78 23 16 Bright area Shadow area A B C Time Complexity O(mB) m : number of sensor nodes in shadow area B : beacon broadcast interval A : 16  19 + 3 = 22 B : 18  22 + 3 = 25 C : 19  23 + 3 = 26 A : 22  26 + 3 = 29 22 25 26 29

11. 11 PAGER Related Work Evaluation Introduction Conclusion PAGER 11 Loop-free Property Messages from bright area ◦ Do not enter a shadow area ◦ Always end up with the BS Messages from shadow area ◦ Always led to bright area All messages will end up with the BS Loop-free !!

12. 12 PAGER Related Work Evaluation Introduction Conclusion PAGER 12 PAGER-M (M for mobility) Bright area  shadow area Sensor node Base station 17 19 14 16 10 20 Shadow area A B C D A : 14  17 + 3 = 20 C : 16  20 + 3 = 23 D : 17  20 + 3 = 23 A : 20  23 + 3 = 26 2026 23

13. 13 PAGER Related Work Evaluation Introduction Conclusion PAGER 13 PAGER-M (M for mobility) Shadow area  bright area Sensor node Base station 23 19 26 23 10 20 Shadow area A B C D A : 20  12 C : 23  17 D : 23  18 12 17 18

14. 14 PAGER Related Work Evaluation Introduction Conclusion Evaluation 14 Simulation NS2 simulator Base station Sensor node Stationary - Randomly distributed 100~500 Sensor nodes - 6~10 Average Degree - 256bps * 7 flows (32byte per packet) Mobile - Randomly distributed 200 Sensor nodes - 6~10 Average Degree - 256bps * 8 flows (32byte per packet) - Communication range : 126m, 155m - Random waypoint motion random speed U(0m/s, 20m/s) control mobility via pause time 1000m

15. 15 PAGER Related Work Evaluation Introduction Conclusion Evaluation 15 Stationary Sensor Networks – 1/3 Max size of shadow area increase as sublinear

16. 16 PAGER Related Work Evaluation Introduction Conclusion Evaluation 16 Stationary Sensor Networks – 2/3 High delivery ratio Short Path Length (nearly optimal)

17. 17 PAGER Related Work Evaluation Introduction Conclusion Evaluation 17 Stationary Sensor Networks – 3/3 Low control overhead Low energy consumption

18. 18 PAGER Related Work Evaluation Introduction Conclusion Evaluation 18 Mobile Sensor Network High delivery ratio Average path length between GPSR and AODV

19. 2015-04-2619 PAGER Related Work Evaluation Introduction Conclusion 19 Conclusion PAGER ◦ Solves dead end problem of location based routing in sensor network ◦ Does not need to memorize past traffic ◦ Provides Nearly shortest path with loop-free ◦ Adaptive to mobility ◦ Good Performance