1. A Presentation by: Noman Shahreyar
Greedy Perimeter Stateless Routing (GPSR) vs. Geographical Energy Aware Routing (GEAR)
A Presentation by:
Noman Shahreyar

2. Outline Introduction Motivation Goals GPSR GEAR Simulation Results
Conclusions

3. Introduction
Topology changes are more frequent in wireless networks as opposed to wired networks
Traditional routing algorithms such as Distance Vector (DV) and Link State (LS) are not efficient (network congestion, mobility overhead) for packet forwarding in wireless networks
Routing protocols based on DV and LS consume enormous network bandwidth and have low scalability

4. Motivation
Routing table exchange proportional to network size & mobility
Nodes often overloaded with participating in the network; not enough time to sense
Routing information storage
Adaptability requirement
End-to-end route maintenance
No support for regional query

5. What to Do ????
Answer is LOCATION !!!!!

6. Why Geographical Routing ???
Geographic routing allows nodes to be
nearly stateless and requires propagation
of topology information for only a single hop
The position of a packet’s destination and next-hop neighbor positions are sufficient for making packet forwarding decisions

7. Find the road traffic flow in region X for time duration t
Why Regional Support ???
What is the average temperature in a region R during time period (t1, t2)
Find the road traffic flow in region X for time duration t

8. Goals Reduce size of topology information stored (state) in the nodes
Provide geography-based forwarding
Minimize the mobility overhead traffic
Extend life-time of the network

9. Geographical Routing Greedy Perimeter Stateless Routing (GPSR)
Geographical Energy Aware Routing (GEAR)

10. GPSR Facts Scalability Location-based communication Nearly Stateless
Routing adaptability
Mobility support

11. Assumptions Source knows its position
Each node knows position of its neighbors by simple beacon message
Sources can determine the location of destinations
Local directory service (Node ID to location mapping), location registration
Bonus: location-based communication make directory service unnecessary

12. GPSR Modes GPSR has two modes of operation for packet forwarding
Greedy Forwarding
Perimeter Forwarding

13. Geographically Closest to Destination
Greedy Forwarding
Geographically Closest to Destination
Destination
Source

14. When Greedy Forwarding Fails ???
Destination X
Reached local maxima

15. Perimeter Forwarding
Destination X

16. Assembling GPSR Together
greedy
fails
Perimeter Forwarding
Greedy Forwarding
have left local maxima
greedy works
greedy fails

17. GEAR Facts Geographic packet forwarding
Extended overall network lifetime
High Scalability
Routing adaptability
Mobility Support
Nearly Stateless
Regional Support
Extension of GPSR

18. Assumptions
Each query packet has target region specified in the original packet
Each node knows its position (GPS) and remaining energy level
Each node knows its neighbors’ position (beacon) and their remaining energy levels
Links (Transmission) are bi-directional

19. GEAR Modes GEAR has two modes of operation for packet forwarding
Energy-aware Regional Forwarding
Recursive Geographic Forwarding / Restricted Flooding

20. Energy-aware Regional Forwarding
Geographically Closest to Region
Region
Source

21. Recursive Geographic Forwarding
Region

22. Restricted Flooding
Region

23. Assembling GEAR Together
Recursive Geographic Forwarding
Region arrived
Source-region
Region
If RGF fails or sparse region
Energy-aware Regional Routing
Restricted Flooding

24. Simulation Environment
Forward packets to all nodes in the region
No need for location database
Static sensor nodes
Existence of localization system
Energy-metrics + Geographical Information utilization

25. Simulation Scenarios Uniform Traffic Distribution
The source and target regions are randomly selected throughout the network
Non-uniform Traffic Distribution (Clustered sources and Destinations)
Sources and Destinations are randomly selected but source-pairs and destination- pairs are geographically close to each other

26. Comparison For Uniform Traffic

27. Comparison For Non-uniform Traffic

28. Total broken pairs vs. Total data delivered

29. Results Uniform Traffic (GEAR vs. GPRS) 25 – 35 % more packet delivery
Non-uniform Traffic (GEAR vs. GPRS)
70 – 80 % more packet delivery
GEAR vs. Flooding
40 – 100 times more packet delivery

30. Goals Achieved !!!! Localized topology information storage
Geography-based Dissemination
Reduced mobility traffic overhead
Extended network life-time

31. Location-aided Routing
Summary
GEAR
GPSR
DSR
Scalability
Energy-Awareness
Regional Support
Location-aided Routing
Periodic Beaconing
Routing Adaptability

32. Conclusions GEAR propagates query to target region without flooding
GEAR provides extended life of the sensor networks
GEAR outperforms GPSR in both uniform and non-uniform scenarios in packet delivery
GEAR performs better in terms of connectivity after partition

33. Issues That I Recommend To Explore
Reliability of packet delivery
Sensor positional error
Secure data transmission
Protocol Implementation in 3-D space

34. References
Yan Yun., Ramesh Govindan, and Estrin Deborah: Geographical and Energy Aware Routing, August 2001
Paper Website:
Brad Karp, H. T. Kung : GPSR-Greedy Perimeter Stateless Routing for Wireless Networks, MobiComm 2000
Paper Website:
Rahul Jain, Anuj Puri, and Raja Sengupta: Geographical Routing Using Partial Information for Wireless Ad Hoc Networks, 1999
Paper Website:
Chenyang Lu: GPSR Ad Hoc Routing III, Fall 2002
Presentation Website:
Brad Karp: Geographic Routing for Wireless Networks, Phd Dissertation, Harvard University, October 2002
Paper Website:

35. A Presentation by: Noman Shahreyar
Greedy Perimeter Stateless Routing (GPSR) vs. Geographical Energy Aware Routing (GEAR)
A Presentation by:
Noman Shahreyar