This document summarizes several geographical routing protocols for wireless sensor networks: 1) Small World Topology-Aware Routing (SWTAR) uses topological awareness to discover routes and avoid voids, achieving high delivery ratios with short paths. 2) Geographic Wireless Reliable Multicast (GeoWiReM) provides efficient multicast delivery within ad hoc regions using passive acknowledgments and local recovery. 3) Energy-aware interference-sensitive geographic routing (EIGR) minimizes energy use and interference by selecting next hops along an anchor list that guides packets along energy-optimal low-interference paths.

1. National Conference on Current Trends in Computer Science and Engineering - CSECONF2012
Geographical Routing Protocols in Wireless Sensor Networks
Shwetha H K1, G R Archana Patel2, Manjunath CR3, DrNagaraj GS4
1,2 nd
Mtech 2 Sem, Dept of CSE, SET, Jain University, archanagr12@gmail.com, shwethahk88@yahoo.com
3
Asst Prof, Dept of CSE, Jain University
4
Prof, Dept of CSE, RVCE, VTU
Abstract: Energy conservation and interference reduction location-based scheme makes it a more efficient, simpleand
are the two ultimate goals in the design of network scalable routing protocol in WSNs.
protocols for wireless sensor networks (WSNs)[1].
Geographic routing protocols on sensor networks II - Small World Topology-Aware Routing
concentrates on finding ways to guarantee data forwarding (SWTAR)
from the source to the destination.Geographic routing
protocols are widely used in WSN due to its great Greedy forwarding is particularly efficient in well-
efficiency, good scalability and computed routing close to connected networks, where the built path is approximately
the best possible. In this paper, we present the study of the shortest path between the sources and the destinations.
geographical routing when energy, link, topology and However, geographic routing suffers from local minimum
geographical information are aware in WSN. Small World phenomenon or local maximum phenomenon, where a
Topology-Aware Routing (SWTAR): the packet delivery packet gets stuck at a node whose neighbors are all further
ratio without the need of the void-handling techniques and away from the destination. This situation indicates that
experience nearly shortest forwarding path. Geographic there is a void area in the geographic distribution of nodes.
Wireless Reliable Multicast (GeoWiReM): On-demand, This technique is inefficient in terms of resource utilization,
forwarding mechanism to deliver packets to ad hoc regions though some advanced flooding based techniques, called as
of interest delimited by geographic position. Energy-aware restricted flooding or partial flooding [2] have been
interference-sensitivegeographic routing (EIGR): proposed.
minimizing the total network energy consumption and The topological awareness(TA) of a node is a subset
reducinginterference, Link-aware geographic routing such that including all the neighbors and some non-
(LAG) :blacklist approach to filter bad link out. neighbor nodes. In geographic routing, it is expected that
TA provides fine topology knowledge around a node and
Keywords:Wireless Sensor Network, Geographical Routing coarse topology knowledge far from the node. Topological
Protocol. awareness, which provides a node with myopic topology
knowledge (neighbor nodes) and nonmyopic topology
knowledge (non-neighbor nodes). These non-neighbor
I - Introduction: nodes are discovered based on a small world model, such
WSN is an emerging technology that promises that a logical small world network is constructed and high
unprecedented ability to monitor and manipulate the delivery packet ratio when network is not connected.
physical world via a network of densely distributed SWTAR can be divided into two steps: the TA discovery
wireless sensor nodes. The nodes can sense the physical and the TA-based packet forwarding.
environment in a variety of modalities, including acoustic, TA discovery: Small world network is pervasive in many
video, seismic, thermal, and infrared, etc. natural and artificial complex networks, and is captured by
A WSN is a multi-hop self organizing network two characteristics: small average path length and high
system. It draws much attention in recent years due to its clustering coefficient [2]. With these characteristics, it has
promising applications in various areas such as industrial been shown that small world network is navigable, i.e.,
process control, battlefield surveillance, environmental each node using only its local information can find a short
monitoring, military surveillance, disaster search and path to any other node in the network.
rescue and commercial applications. Sensor networks are TA discovery scheme based on a small world
usually composed of a large number of sensing devices, model, required when a network is first turned on and it
each with limited computing and radio capabilities. Each quickly constructs a logical small world network based on
node in the sensor network may consist of one or more the discovered topology awareness.
sensors, a low power radio, portable power supply, and TA-based geographic routing :Algorithm includes two
possibly localization hardware, such as a GPS (Global cases, forwarding scheme and backwarding scheme[2].
Positioning System) unit or a ranging device.
Geographic routing[1], as a simple, efficient andscalable Three performance metrics are used to evaluate the
strategy, is widely adopted in wireless ad hocand sensor performance of the proposed routing algorithm:
networks. During packetforwarding, greedy forwarding is i. Packet delivery ratio (PDR), the ratio of the data
used as the basic operation of the geographic routing, in packets successfully delivered to the destinations.
which the packet is greedily forwarded to the neighbor ii. Average path length (APL), the averaged hops that the
node geographically closest to the destination. Geographic packets are relayed until reaching the destination.
routing has been considered as an attractiveapproach since iii. Average normalized size of the TA (ANS),This metric
it exploits pure location information insteadof global evaluates the averaged storage size of the TA.
topology information to route data packets, andthis
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2. National Conference on Current Trends in Computer Science and Engineering - CSECONF2012
III - Geographic Wireless Reliable Multicast delivery and so on. However, a common defect of these
(GeoWiReM) protocols is that data packets are not surely delivered along
an energy-efficient path when detouring mode is involved
The battlefield of the future will be dominated by complex in the routing.
and dynamic networks of sensors, Warfighters and critical Energy-aware interference-sensitive geographic
systems that will be required to exchange, collaborate and routing (EIGR) protocol overcomes this problem by taking
integrate vast amounts of information in some operationally into consideration of both total energy conservation and
relevant way. To support the needs for this complex vision interference reduction as the optimization objectives
we have GeoWiReM [3] protocol which provides efficient simultaneously.
delivery via adhoc packet multicast, end-to-end reliability EIGR utilizes an anchor list to guide packet
and repair mechanisms. delivery so that data packets sent along the anchor list will
GeoWiReM employs forwarding mechanisms as never encounter local minimum. For energy conservation
passive and negative acknowledgments (NACK), selective and interference reduction between two adjacent anchor
retransmission for missing or corrupt data, implosion nodes, each forwarding node selects the neighbour with the
avoidance and local recovery. minimum interference from energy optimal relay area as
To establish a GeoWiReM mesh, a source will the next forwarding node and adjusts its transmission
initially broadcast a GeoQuery (GQ) message to its power so as just to reach the selected neighbour.
neighbors, all of whom are obligated to forward the packet
unless it is determined that the packet is already beyond the Anchor list
target destination area or is moving away from it. Each Each source node needs to obtain an anchor list
intermediary node will save the upstream address and before sending data packets. To obtain the anchor list, the
geographic information, update the GQ message with its source node first adaptively broadcasts a beacon packet
address,then forward the GeoQuery using subnet broadcast. toits neighbours for announcing the location information of
When a destination node receives a GQ, it will send a itself at the maximum transmission power. When a
GeoReply (GR) message back to the source, via the neighbour receives this packet, it stores the location
specific intermediary nodes identified in the GQ header. information of the sender in its visible neighbourhood and
Once the reply message has reached the source, all the then broadcasts a new beacon packet to its neighbours at
forwarding nodes on the path from the source to the the maximum transmission power. Here a beacon message
receiver have been identified and have marked themselves only includes the location information of the sender and the
as belonging to this multicast group’s forwarding group, beacon message is only used for exchanging location
thus establishing the forwarding mesh for this multicast information between neighbours.
group. The source may now simply transmit multicast data Then, the source node sends a burst packet to the
normally, using the multicast IP address and the mesh will destination node using an existing geographic routing
forward the data to the subscribed receivers. The mesh can protocol, such as GPSR [4]. GPSR uses greedy mode
be refreshed manually or periodically to adapt to the whenever possible and switches to detouring mode when
changing topology of the mobile ad hoc network. the data packets encounter a hole. Once detouring mode is
The GeoWiReM protocol uses a mesh-based involved in the routing, we introduce anchor nodes for
forwarding mechanism to deliver messages to all nodes guiding subsequently data delivery.
within a defined area of interest. The protocol provides
several reliability mechanisms and is able to support mobile Metrics are used for performance evaluations:
roaming nodes as well as statically emplaced node. • Energy consumption: The total energy consumption
by all sensor nodes which have participated in data
forwarding.
IV-Energy-aware interference-sensitivegeographic • Packet delivery ratio: The ratio of the number of data
routing(EIGR) packets received by the destination nodes to those sent
by the source nodes.
EIGR[4] protocol, which focuses on minimizing • Control overhead: The number of control packets
the total network energy consumption and reducing generated during simulation time.
interference. EIGR adaptively uses an anchor list to guide • Average end-to-end delay: The delay between the time
data delivery, and selects the minimum-interference link at which a data packet was originated at the source
from energy-optimal relay region for data delivery. node and the time it reaches the destination node. Data
Generally, geographic routing works in two packets that get lost in route are not considered.
modes, namely greedy mode and detouring mode. Greedy Delays due to queuing and retransmissions are
mode works if at least one neighbor of current node exists included in the delay metric.
that can make progress towards the destination. Detouring
mode works if such a node does not exist. In detouring V-Link-aware geographic routing (LAG)
mode, data packets are usually sent along the boundary of Geographic routing using traditional greedy
hole to detour the hole by the schemes such as right-hand- metric decreases successful packet delivery on non-ideal
rule until greedy mode is possible. communication link. To solve this problem LAG [5]
The energy-aware geographic routing protocols protocol is proposed. The LAG not only expects the
achieve various goals, such as maximizing networklifetime minimum Euclidean distance between neighbor nodes and
or minimizing the energy consumption of end-to-end data the destination, but also requires the better link quality
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3. National Conference on Current Trends in Computer Science and Engineering - CSECONF2012
between the current node and relevant neighbor nodes
during the selection of the next hop. To avoid selecting the [3] Mont OrpillaJeffrey PalumboUS Army CERDECFort
neighbor nodes with bad links as the next hop, the LAG Monmouth, NJScott ThomasIvan EbyWayne Franklin,Trident
employs the blacklist approach to filter them out under the Systems Inc. Fairfax, “A Geographically-Aware, Reliable
Multicast Protocol for Tactical Sensor Network”, IEEE, pp. 1-6
threshold of link quality.Instead of the neighbor closest to
the destination, LAG selects the neighbor with the best [4] H. Huang G. Hu F. Yu Z. Zhang,” Energy-aware interference-
trade-off between proximity and link quality. sensitive geographicrouting in wireless sensor networks”,IEEE,
Some of previous work uses additional probe IET Commun., 2011, Vol. 5, Iss. 18, pp. 2692–2702
messages for link cost estimation in the bootstrapping
phase. However, such control messages consume already [5]Heng Chen, DepeiQian, Weiguo Wu, Weiwei Fang,” Link-
scarce network resources. Also, network environments may Aware Geographic Routing in Wireless Sensor
change over time (e.g., due to mobility or congestion), and Networks”,IEEE,2009,pp. 937-942.
old link estimates may become obsolete. We have exploit
MAC-level information, so that link quality estimation is
adaptive to changing environments, yet incurs minimal
control overhead. To prevent from using the bad links
completely, LAG also employs a blacklist selection scheme
which is used just before each selection of closest
neighbors.
We introduce the traditional greedy Metric to
achieve better link quality. Then, we use a new link metric
for geographicrouting called Sequence Reception rAtion
and Blacklist (SRAB) to remove weak-links.
Traditional greedy metric:
The principle used in the next hop selection is
that the neighbor node not only makes as large progress
toward the destination as possible, but also has high link
quality. We can achieve this goal by using the new link
metric described next.
Sequence reception ratio and blacklist (SRAB) metric:
On the lossy wireless link, we assume packets
reach neighbor nodeafter retransmissions. During the
retransmission period, the current node receives packets
continually. These packets are placed in the interface queue
which locates between link layer and MAC layer. Due to
the limited length of IFQ, the more increases, the more
packets drop accordingly for the overflow of IFQ. As a
result, the packet delivery ratio is degraded dramatically.
VI – Conclusion
This paper presents a study on four geographical
routing protocols, SWTAR for topological awareness,
GeoWiReM for deliver messages within a defined area,
EIGR considering both the total energy conservation and
interference reduction as the optimization, LAG takes link
quality into account besides the progression to the
destination.
Reference
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Wireless Sensor Networks: a survey”, IEEE Wireless
Communications • December 2004,pp . 1-23.
[2] Feng Xi, Zhong Liu, ”Small World Topology-Aware
Geographic Routing in Wireless SensorNetworks
”,IEEECommunications and Mobile
Computing,2009,pp.116-120
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