1. National Conference on Current Trends in Computer Science and Engineering - CSECONF2012
Energy Efficient Routing in Wireless Sensor Networks
Gunti Spandan1, Prashanth.C2, C R Manjunath3
1,2 nd
MTech 2 sem, Dept of CSE, SET, Jain University, spandangunti@gmail.com,prashu.kc@gmail.com
3
Asst prof, Dept of CSE, Jain University, manjucr123@gmail.com
Abstract:Wireless Sensor Networks present a great Energy-efficient multicast routing protocol is of
potential in monitoring systems. Routing problem is one of paramount importance for many new applications being
the most important issues in a wireless sensor network developed for the resource scarce WSN.
(WSN).Any routing protocol designed for wireless sensor II - MULTICAST AD HOC ON-DEMAND
networks is should take into consideration, the challenging DISTANCE V ECTOR(MAODV)
factors like fault tolerance, energy efficiency, scalability, MAODV like DSR has the same on demand
latency, power consumption and network topology.The routing characteristics, but uses an entirely different
stringent requirement of energy budget has been an approach for maintaining routing table information. As
emerging issue in the design specification for a wireless MAODV belongs to the family of on demand routing
sensors network (WSN). In this paper we present astudy on protocol,so it follows the conventional scheme of
demand &clustermulticast routing protocols with energy- maintaining routing table i.e. only one entry will be made
efficiency perspective. for each destination.The entry made contains two
information's, first one is it will update its destination with
Keywords: multicast, routing, wireless sensor the next hope and then the next hope will update its
networks, energyefficient. sequence number which shows that how recently this node
I - Introduction has updated.
Wireless sensor network(WSN) is a multi-hop MAODV also updates the upstream link if any
wireless networks consists of a large of small-size, low-cost link associated against this entry goes down.MAODV also
and low-power sensor nodes which are capable of sensing, uses the same broadcasting mechanism as used by the DSR
computation and communication. WSN take advantage of for discovery within the network but it is different from
deployment rapidly and strong survivability without fixed AODV as it only receives route reply from those nodes
network support,but also with features of dynamic topology which belongs to a family of multicast group.
structure and energy resources are limited and so on.The
application of WSN technology is a revolution of perceived
and collection of information andused for various
applications such as habitat monitoring, automation, and
agriculture [1].
Routing in WSNs is very challenging due to the
inherent characteristics that distinguish these networks
from other wireless networks like mobile ad hoc networks
or cellular networks.Sensor nodes are tightly constrained in
terms of energy, processing, and storage capacitiesthey
require careful resource management. Multicast is the
communication paradigm of one-to-many or many-to-
many, based on defined groups and constituted by
members, whose interest is to receive/share the same
information for a specific application.Multicast routing is to
find a multicast tree which is rooted from the source and Figure 1 MAODV Joining Process- Image reproduced
spans all destination nodes.The whole routing process The group leader broadcast a HELLO message to all the
includes two phases. The first phase is to seek a minimal nodes and they update their request table upon this group
energy path from the sink to the access point based on the HELLO message. If a new node is interested to be a part of
idea of dynamic programming. The second phase is to join this group, initially it will generate a route request
search for a broadcast tree between the access point and the packet (RREQ). The node unicast this request if it already
destination nodes in the multicast region [2]. knows the group leader address otherwise it will be
Energy Efficient Routingmethod is proposed for broadcasted. The group leader or any other node of the
a static wireless sensors network, which consists of a large requested group having a grater sequence number than that
number of energy-constrained sensors and a few hubs as of the RREQ packet isallowed to respond. As the message
the cluster heads of sensors.Since each battery-powered is broadcasted the members of the group or the group
sensor only has limited energy resource and the battery leader will receive several RREQ packets but it will
recharge or replacement is impractical, a network with consider only one having the highest sequence number and
energy-aware design becomes important to achieve the least hope count. After selecting the request packet, it
desired lifetime performance. unicast a route reply packet to the desired node. This
replying packet consists of the sequence number which is
recently updated and the distance of the node from the
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2. National Conference on Current Trends in Computer Science and Engineering - CSECONF2012
group leader. The requesting node at its end also attribute from the user. The CH broadcasts the attribute,
receivesnumerous replies from different nodes and group hard threshold (HT), soft threshold (ST), schedule and
leader but selects only one having the shortest distance count time (CT) parameters to the cluster members. The
among all RREP packets and most recently received. After sensor nodes sense continuously. If the sensed value is
selecting the most suitable route it generates a multicast above the HT it is stored in the internal variable (SV) and
activation packet (MCAT) to its neighbor node to enable transmitted to the CH through the TDMA schedule
the desired route.Figure2 shows the node joining process of assigned for it. All the clusters formed here may not have
MAODY. uniform number of sensor nodes. The cluster formed with
maximum number of nodes requires more time to aggregate
III - THRESHOLDSENSITIVEENERGY the captured data from nodes and transmit to BS than the
EFFICIENT SENSOR NETWOR K ( TEEN) cluster with minimum number of nodes.
Threshold sensitive Energy Efficient sensor Suppose in any cluster, adjacent nodes have the
Network (TEEN)[5] belongs to on-demand routing similar sensed data to transmit then those nodes are formed
protocols category and mostly used for time crucial as a pair. Only one node from the pair will respond to the
applications. In TEEN, nodes have two levels of cluster query while the another node goes to sleep mode. The node
heads and also they follow hierarchical clustering design. which responds to the query is considered as active node
After nodes haveselected their cluster head, user needs to and the other node which goes to sleep mode is considered
manually enter the attribute values, which will be as sleep node. This protocol supports one time query,
broadcasted by cluster head in form of two parameters soft historical query and persistent query. The BS needs to
threshold and hard threshold. respond to nodes query only after receiving the data from
The sensor nodes will start transmitting data all the CHs.
when minimum threshold value is greater than hard As the cluster head of cluster with maximum
threshold. Another variable called sensed value is used for members require more time to communicate with BS a
transmitted data.Teen savesdata continuously. The soft modified TDMA schedule is assigned as per which BS
threshold also saves energy by reducing the transmission, needs to wait until data from CH of cluster with more
when there no or little change in the attribute value. Cluster members reaches it. Apart from responding to time critical
head will definitely consume more energy than a normal events, the nodes were also forced to transmit data to CH at
node because it needs to do extra processing. periodic intervals as CT even though the sensed data does
not exceed the threshold value. Where CT is the maximum
time period between two successive reports sent by a node.
Due to this periodic transmission, frequent updates of the
nodes sensed value are transmitted to its CH. In this
protocol the energy consumption can be reduced by
properly selecting the CT and threshold values.
CDMA schedule is used to avoid collisions
during cluster heads communicating with BS.
The attributes can be changed during the every cluster head
change time. The main drawback ofthis protocol is the
additional complexity required to implement the threshold
functions and CT.
Figure 2 Operational Flow of TEEN
The biggest disadvantage of this protocol is that when hard
threshold value is higher than sensed value there will be no
transmission to clustered head from node, so the cluster
head will have no information updation even if the node is
no more in network. This problem can easily be addressed
by fixing soft threshold to as minimum value as possible
even though it would increase energy consumption but
nodes sensibility will also be increased. This protocol uses
Time Division Multiple Access (TDMA) as a scheduler to
send data between nodes and their cluster heads.Figure 2
shows operational flow diagram of TEEN protocol.
IV - Adaptive Periodic Threshold-sensitiveEnergy
Efficient sensor network protocol(APTEEN)
APTEEN, is a hybrid protocol proposed in [5] for V - SPEED Protocol
both periodic data collection and time criticalevents. In this, SPEED maintains a desired delivery speed across
cluster is formed with 1st level and 2nd level cluster heads. sensornetworks by both diverting traffic at the
After selecting the cluster head (CH) it receives the
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3. National Conference on Current Trends in Computer Science and Engineering - CSECONF2012
networkinglayer and locally regulating packets sent to the
MAC layer. VI - REAL-TIME POWER-AWARE ROUTING
It consists of the following components: An API, A IN SENSOR NETWORKS (RPAR)
neighbor beacon exchange scheme, A delay estimation RPAR is a real time protocol proposed in which achieves
scheme, the Stateless Non-deterministic Geographic application-specified communication delays at low energy
Forwardingalgorithm (SNGF), A Neighborhood Feedback cost by dynamically adapting transmission power and
Loop (NFL), Backpressure Rerouting, Last mile processing routing decisions based on packet deadlines. The primary
As shown in Figure 4,.SNGF is the routing module design objective of RPAR is to increase the number of
responsible for choosing the next hop candidate that can packets which meets their deadlines. Another
support the desired delivery speed. NFL and Backpressure distinguishing feature of RPAR is that it handles realistic
Rerouting are two modules to reduce or divert traffic when properties of WSN such as lossy links, limited memory,
congestion occurs, so that SNGF has available candidates and bandwidth. RPAR has four components:
to choose from. The last mile process is provided to support A. Dynamic velocity assignment policy
the three communication semantics mentioned before. It uses the velocity assignment policy to map a packet’s
Delay estimation is the mechanism by which a node deadline to a required velocity.
determineswhether or not congestion has occurred. And B. Delay estimator
beacon exchange provides geographic location of the This evaluates the one-hop delay of each forwarding choice
neighbors so that SNGF can do geographic based routing. in the neighbor table, i.e. the time a node takes to deliver a
packet to neighbor N at power level p.
C. Forwarding policy
Based on the velocity requirement and the information
provided by the delay estimator, It forwards the packet
using the most energyefficient forwarding choice in its
neighborhood table that meets the required velocity.
D. Neighborhood manager
This manager attempts to find a new forwarding choice that
meets the required velocity through power adaptation and
neighbor discovery, when the forwarding policy cannot
find a forwarding choice that meets the required velocity in
the neighbor table. RPAR trades-off between
thecommunication delay and throughput. It trades capacity
Figure 4 SPEED Protocol- Image reproduced and energy for improving latency byincreasing
transmission power and when there are loose deadlines, the
transmission power isadjusted accordingly. The delay
SPEED facilitates real-time communication because it bounds for each packet is provided by the application
provides desired transfer rate over the network. It provides
different types of communication services i.e. VII - MULTIPATH AND MULTIPLE-SP
unicast,multicast and any cast. Stateless Non-deterministic EED(MMSPEED)
Geographic Forwarding (SNGF) identifies next hop MMSPEED is an extension of SPEED
whenever source node transmit the data. protocol[4]. The aim of MMSPEED is to make routing
decisions locally on the nodes and also to facilitate
SPEED only stores the information of very next node, so it differentiated QOS in timeless and reliable domain. To
requires less memory. Neighboring beacon is used for make decisions locally without maintaining end-to-end
information interchange between nodes. To identify routes, it uses geographic routing method. It assumes that
trafficchanges in the network two types of on demand main identifier for destination is its geographic location
beacons are used i.e. delay estimation and back pressure rather than node ID. Periodic location update packets are
beacon. used to instantly update the location information with
SPEED uses Backpressure rerouting mechanism neighbors, so that every node is aware of its very next
for congestion controlhandling in the network. Packets are neighbor within its range. Each node makes pre-packet
given an alternative route to destination and normally no decisions depending on the geographic location of the
packets are dropped in Backpressure rerouting mechanism. neighbor.
Only when there is no alternative route to destination and The geographic localized routing mechanism has
network become very congested than the packets are many advantagesover traditional routing approach:
dropped. It will consume less energy if there is no i) This approach is suitable for larger networks
congestion in the network and also it will save energy by (scalability).
selecting shortest path to the destination but if there is ii) Minimum delay suitable for time-critical applications.
congestion in the network, the energy consumption will be iii) Dynamic adoption to network topology changes.
slightly higher. SPEED is a hybrid protocol because it To achieve higher performance, MMSPEED
combines the functionality of MAC and network layer to needs MAC layerto support following function:
minimize the delay and to provide better response to i) To assign priority for accessing shared-medium
congestion. Figure 4 shows the protocol structure of dependingupon the speed layer.
SPEED protocol. ii) Reliable packet delivery
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4. National Conference on Current Trends in Computer Science and Engineering - CSECONF2012
iii) Average delay measurement (3)The cluster head node need to communicate with the
iv) Measurement of loss to individual neighbors sink node to complete the data fusion work, energy
consumption increased.
VIII - Conclusion:
Providing an energy-efficient multicast routing protocol is
of paramount importance for many new applications being
developed for the resource scarce in WSNThis paper
presents an overview of different energy efficientmulticast
routing protocols for wireless sensor networks.
Generally,all of them needs low processing and memory
forrouting that means lower energy requirements.
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VIII - LEACH Protocol 6.PAN Xue-feng, LI La-yuan,”Design of an Energy Balanced
Based Routing Protocol for WSN”IEEE 2011.
In the LEACH protocol, random, adaptive, self- 7.Taehee Kim, Hosung Park, Min-Sook Jin, BatzorigSambuu, and
organizing cluster formation method. Figure 6depicts a Sang-Ha Kim “Energy-balancing Multicast Routing Protocolfor
wireless sensor network protocol based on LEACH is Wireless Sensor Networks” IEEE 2008.
divided into five clusters, each cluster has a black circle
represents the first cluster node , the rest of the white circle
indicates a non cluster head node. Each cluster has a cluster
head node, protocol randomly selecting cluster head node
cycle, the energy of the entire network load equally
distributed to each sensor node can achieve lower energy
consumption, the purpose of improving network lifetime
Figure 6 LEACH protocol cluster structure
From the above analysis shows that LEACH protocol has
the following deficiencies:
(1) the use of cluster head nodes in random rotation
method which can reduce the energyconsumption, but
repeatedly re-clustering will still consume more energy.
(2) different clusters, the cluster head node and cluster head
nodes from non-different, the communication process
increases the energy consumption of cluster head.
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