Greedy Perimeter Stateless
Routing (GPSR)
vs.
Geographical Energy Aware
Routing (GEAR)
A Presentation by:
Noman Shahreyar
Outline
Introduction
Motivation
Goals
GPSR
GEAR
Simulation
Results
Conclusions
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
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
What to Do ????
Answer is LOCATION !!!!!
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
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
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
Geographical Routing
Greedy Perimeter Stateless Routing
(GPSR)
Geographical Energy Aware Routing
(GEAR)
GPSR Facts
Scalability
Location-based communication
Nearly Stateless
Routing adaptability
Mobility support
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
GPSR Modes
 GPSR has two modes of operation for
packet forwarding
 Greedy Forwarding
 Perimeter Forwarding
Greedy Forwarding
Geographically
Closest to
Destination
Destination
Sourc
e
When Greedy Forwarding
Fails ???
Destination
X
Reached local maxima
Perimeter Forwarding
Destination
X
Assembling GPSR Together
greedy
fails
Greedy Forwarding
Perimeter Forwarding
have left local maxima
greedy works
greedy fails
GEAR Facts
Geographic packet forwarding
Extended overall network lifetime
High Scalability
Routing adaptability
Mobility Support
Nearly Stateless
Regional Support
Extension of GPSR
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 bidirectional
GEAR Modes
GEAR has two modes of operation for
packet forwarding
 Energy-aware Regional Forwarding
 Recursive Geographic Forwarding /
Restricted Flooding
Energy-aware Regional
Forwarding
Geographically
Closest to Region
Region
Sourc
e
Recursive Geographic
Forwarding
Region
Restricted Flooding
Region
Assembling GEAR
Together
Recursive Geographic
Forwarding
Region
arrived
Source-region
Region
If RGF fails or
sparse region
Energy-aware Regional
Routing
Restricted Flooding
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
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 destinationpairs are geographically close to each other
Comparison For Uniform Traffic
Comparison For Non-uniform
Traffic
Total broken pairs vs. Total
data delivered
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
Goals Achieved !!!!
Localized topology information
storage
Geography-based Dissemination
Reduced mobility traffic
overhead
Extended network life-time
Summary
GEAR
Scalability
EnergyAwareness
Regional Support
Location-aided
Routing
Periodic
Beaconing
Routing
Adaptability
GPSR
DSR
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
Issues That I Recommend
To Explore
Reliability of packet delivery
Sensor positional error
Secure data transmission
Protocol Implementation in 3-D
space
References

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 2000
Paper 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 2002
Presentation Website: http://www.cse.wustl.edu/~lu/cs537s/presentations/gpsr.ppt

Brad Karp: Geographic Routing for Wireless Networks, Phd Dissertation, Harvard
University, October 2002
Paper Website: http://citeseer.nj.nec.com/472843.html
Greedy Perimeter Stateless
Routing (GPSR)
vs.
Geographical Energy Aware
Routing (GEAR)
A Presentation by:
Noman Shahreyar