Greedy Perimeter Greedy Perimeter Stateless Routing Stateless Routing

(GPSR)(GPSR)vs.vs.

Geographical Energy Geographical Energy Aware Routing (GEAR)Aware Routing (GEAR)

A Presentation by:A Presentation by:

Noman ShahreyarNoman Shahreyar

OutlineOutline Introduction Motivation Goals GPSR GEAR Simulation Results Conclusions

IntroductionIntroduction 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

MotivationMotivationRouting table exchange proportional

to network size & mobilityNodes often overloaded with

participating in the network; not enough time to sense

Routing information storageAdaptability requirementEnd-to-end route maintenanceNo support for regional query

What to Do ????What to Do ????

Answer is Answer is LOCATION !!!!!LOCATION !!!!!

Why Geographical Why Geographical Routing ???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

Why Regional Why Regional Support ???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

GoalsGoalsReduce size of topology information

stored (state) in the nodes

Provide geography-based forwarding

Minimize the mobility overhead traffic

Extend life-time of the network

Geographical Geographical RoutingRouting

Greedy Perimeter Stateless Routing (GPSR)

Geographical Energy Aware Routing (GEAR)

GPSR FactsGPSR FactsScalability Location-based communicationNearly StatelessRouting adaptabilityMobility support

AssumptionsAssumptions 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

GPSR ModesGPSR Modes GPSR has two modes of operation for

packet forwarding

Greedy Forwarding

Perimeter Forwarding

Greedy Greedy ForwardingForwarding

Source

Destination

Geographically Closest to

Destination

When Greedy When Greedy Forwarding Fails ???Forwarding Fails ???

Destination

X

Reached local maxima

Perimeter Perimeter ForwardingForwarding

X

Destination

Assembling GPSR Assembling GPSR TogetherTogether

Perimeter Forwarding

greedy

fails

have left local maximagreedy failsgreedy works

Greedy Forwarding

GEAR FactsGEAR FactsGeographic packet forwardingExtended overall network lifetime High ScalabilityRouting adaptabilityMobility SupportNearly Stateless Regional SupportExtension of GPSR

AssumptionsAssumptionsEach query packet has target region

specified in the original packetEach node knows its position (GPS)

and remaining energy levelEach node knows its neighbors’

position (beacon) and their remaining energy levels

Links (Transmission) are bi-directional

GEAR ModesGEAR Modes GEAR has two modes of operation for packet

forwarding

Energy-aware Regional Forwarding

Recursive Geographic Forwarding / Restricted Flooding

Source

Region

Geographically Closest to

Region

Energy-aware Energy-aware Regional Regional

ForwardingForwarding

Recursive Geographic Recursive Geographic ForwardingForwarding

Region

Restricted Restricted FloodingFlooding

Region

Assembling GEAR Assembling GEAR TogetherTogether

Region

Region arrived

If RGF fails or sparse region

Energy-aware Regional Routing

Source-region

Restricted Flooding

Recursive Geographic Forwarding

Simulation Simulation EnvironmentEnvironment

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

Simulation Simulation ScenariosScenarios

Uniform Traffic DistributionThe 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

Comparison For Uniform Comparison For Uniform TrafficTraffic

Comparison For Non-Comparison For Non-uniform Trafficuniform Traffic

Total broken pairs vs. Total broken pairs vs. Total data deliveredTotal data delivered

ResultsResults 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

Goals Achieved !!!!Goals Achieved !!!!

Reduced mobility traffic overhead

Localized topology information storage

Extended network life-time

Geography-based Dissemination

SummarySummaryGEARGEAR GPSRGPSR DSRDSR

Scalability

Energy-Awareness

Regional Support

Location-aided Routing

Periodic Beaconing

Routing Adaptability

ConclusionsConclusionsGEAR propagates query to target region

without floodingGEAR provides extended life of the sensor

networks GEAR outperforms GPSR in both uniform

and non-uniform scenarios in packet deliveryGEAR performs better in terms of

connectivity after partition

Issues That I Issues That I Recommend To Recommend To

Explore Explore Reliability of packet delivery Sensor positional error Secure data transmission Protocol Implementation in 3-D

space

ReferencesReferences Yan Yun., Ramesh Govindan, and Estrin Deborah: Geographical and Energy

Aware Routing, August 2001 Paper Website: http://citeseer.nj.nec.com/shah02energy.html

• Brad Karp, H. T. Kung : GPSR-Greedy Perimeter Stateless Routing for Wireless Networks, MobiComm 2000Paper Website: http://citeseer.nj.nec.com/karp00gpsr.html

Rahul Jain, Anuj Puri, and Raja Sengupta: Geographical Routing Using Partial Information for Wireless Ad Hoc Networks, 1999 Paper Website: http://citeseer.nj.nec.com/336698.html

Chenyang Lu: GPSR Ad Hoc Routing III, Fall 2002Presentation Website: http://www.cse.wustl.edu/~lu/cs537s/presentations/gpsr.ppt

Brad Karp: Geographic Routing for Wireless Networks, Phd Dissertation, Harvard University, October 2002Paper Website: http://citeseer.nj.nec.com/472843.html

Greedy Perimeter Greedy Perimeter Stateless Routing Stateless Routing

(GPSR)(GPSR)vs.vs.

Geographical Energy Geographical Energy Aware Routing (GEAR)Aware Routing (GEAR)

A Presentation by:A Presentation by:

Noman ShahreyarNoman Shahreyar