Wireless Sensor Network, 2012, 4, 65-75
http://dx.doi.org/10.4236/wsn.2012.43010 Published Online March 2012 (http://www.SciRP.org/journal/wsn)
An Integrative Comparison of Energy Efficient Routing
Protocols in Wireless Sensor Network
Ali Norouzi1, Abdul Halim Zaim2
1Department of Computer Engineering, Istanbul University (Avcilar), Istanbul, Turkey
2Department of Computer Engineering, Istanbul Commerce University (Eminonu), Istanbul, Turkey
Email: norouzi@cscrs.itu.edu.tr, azaim@iticu.edu.tr
Received December 8, 2011; revised January 11, 2012; accepted January 30, 2012
ABSTRACT
Many advances have been made in sensor technologies which are as varied as the applications; and many more are in
progress. It has been reasonable to design and develop small size sensor nodes of low cost and low power. In this work,
we have explored some energy-efficient routing protocols (LEACH, Directed Diffusion, Gossiping and EESR) and their
expansions (enhancements), and furthermore, their tactics specific to wireless sensor network, such as data agg regation
and in-network processing, clustering, different node role assignment, and data-centric methods. After that we have
compared these explored routing protocols based on different metrics that affect the specific application requirements
and WSN in general.
Keywords: Wireless Sensor Network; Routing Protocol; Energy Consumption; LEACH; Directed Diffusion; Gossiping;
EESR
1. Introduction
Wireless Sensor Networks consist of tiny sensor nodes
that, in turn, consist of sensors (temperature, light, humi-
dity, radiation, and more), microprocessor, memory, trans-
ceiver, and power supply. In order to realise the existing
and potential applications for WSNs, advanced and ex-
tremely efficient communication protocols are required.
WSNs are application-specific, so the design requirements
of WSNs change according to the application. Hence, rout-
ing protocols’ requirements are changed from one appli-
cation to another. For instance, the requirements of a rout-
ing protocol designed for environmental applications is
different from that designed for military or health appli-
cations in many aspects. As a result, routing protocols’
requirements are as diverse as applications’. Some of the-
se are: Scalability, Latency, Throughput, Recourse Awa-
reness, Data Aggregation, Opti mal Rou te, over-h ead, an d
other metrics. Some applications need some of these me-
trics to be provided and other applications need others to
be provided. However, routing protocols of all Wireless
Sensor networks, regardless of the application, must try
to maximise the network life time and minimise the en-
ergy consumption of the overall network. For these rea-
sons, the energy consumption parameter has higher pri-
ority than other factors.
2. Routing Protocols in Wireless Sensor
Network
Due to these differences, many new algorithms have
been proposed for the routing problem in WSNs, taking
into account the inherent specification of WSNs along
with the application and architecture requirements.
2.1. LEACH Protocol
Low-Energy Adaptive Clustering Hierarchy (LEACH) is
a clustering based protocol that uses a randomised rota-
tion of local cluster base stations. The nodes in LEACH
are divided into clusters and each cluster consists of
members called Cluster Members and a coordinator node
called the Cluster Head, CH. The cluster heads are not
selected in the static manner that leads to quick die of
sensor nodes in the network. However, the randomised
protocol has been used in order to balance the energy
consumption among the nodes by distributing the CH’s
role to the other nodes in the network. Furthermore,
LEACH uses Time Division Multiple Access (TDMA)
protocol in order to regulate the channel access within a
cluster [1].
It is the responsibility of the CHs to assign TDMA
slots to the cluster members. The peer to peer communi-
cation between the CH and a member is done just during
the time slot that assigned to that member, and the other
members will be in their sleep state. Hence, it decreases
the energy dissipation; see Figure 1. Moreover, LEACH
uses the TDMA communication protocol to decrease the
interference between the clusters.
LEACH has been produced to overcome the disad-
vantages of the Flat-Architecture Protocols that consume
C
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66
Figure 1. LEACH protocol and TDMA schedules
more energy [2]. The CH aggregates/combines the col-
lected data by the nodes to the smaller size and mean-
ingful data, and then sends the aggregated data to the
sink consuming less energy. LEACH tries to send the
data over short distances and reduce number of the tran-
smissions, where the energy consumptions depend on the
distance and data size. As a result, the main problem with
LEACH is the direct sending of CH to the sink, espe-
cially when these CHs are located far away from the sink.
However, allowing the multi-hop tran smissio n to th e sink
through other CHs will solve this issue, where the CH
just forwards the data to others until it reaches the sink
and does not have to re-aggregate the data come from
other CHs.
LEACH, compared to the direct communication and
other minimum energy routing protocols, achieves a sig-
nificant reduction in energy dissipation. Finally, th e main
properties (advantages and disadvantages) of LEACH
include [1,2].
2.2. Advantages of LEACH
It limits most of the communication inside the clus-
ters, and hence provides scalability in the network.
The CHs aggregates the data collected by the nodes
and this leads to a limit on the traffic generated in th e
network. Hence, a large-scale network without traffic
overload could be deployed and better energy efficie-
ncy compared to the flat-topology could be achieved.
Single-hop routing from node to cluster head, hence
saving energy.
Distributiveness, where it distributes the role of CH to
the other nodes.
It increases network lifetime in three ways. Firstly,
distributing the role of CH (consumes more energy
than normal nodes) to the other nodes. Secondly, ag-
gregating the data b y the CHs. Finally, TDMA, which,
assigned by the CH to its members, puts most of the
sensor in sleep mode, especially in event-based ap-
plications. Hence, it is able to increase the network
lifetime and achieve a more than 7-fold reduction in
energy dissipation compared to direct communication
[1].
It does not require location information of the nodes
to create the clusters. So, it is powerful and simple.
Finally, it is dynamic clustering and well-suited for
applications where constant monitoring is needed and
data collection occu rs periodically to a centralised lo-
cation.
2.3. Disadvantages of LEACH
It significantly relies on cluster heads and face ro-
bustness issues such as failure of the cluster heads.
Additional overheads due to cluster head changes and
calculations leading to energy inefficiency for dyna-
mic clustering in large networks.
CHs directly communicate with sink—there is no in-
ter cluster communication, and this needs high trans-
mission power. Hence, it does not work well in large-
scale networks that need single-hop communication
with sink.
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A. NOROUZI ET AL. 67
CHs are not uniformly distributed; CHs could be lo-
cated at the edges of the cluster.
CH selection is random, which does not take into ac-
count energy consumption.
Finally, it does not work well in the applications that
cover a large area that requires multi-hop inter cluster
communication.
2.4. Improvements of LEACH
Due to some drawbacks of LEACH, much research has
been done to make this protocol perform better. Some of
these pieces of research are: E-LEACH, TL-LEACH,
M-LEACH, LEACH-C and V-LEACH [3].
2.4.1. E-LEACH
Energy-LEACH protocol improves the CH selection pro-
cedure. Like LEACH, it divided into rounds, where in
the first round all nodes have the same probability to be
CH. However, after the first round the remaining energy
of each node is different and the node with high residual
energy will be chosen as CH rather than those with less
energy [4].
2.4.2. TL-LEACH
in LEACH, the CH sends the data to the base station in
one hop. However, in Two-Level LEACH, the CH col-
lects data from the cluster members and relays the data to
the base station through a CH that lies between the CH
and the base station [5].
2.4.3. M- L E ACH
As mentioned above, in LEACH, the CH sends the data
to the base station in one hop. In Multi-hop-LEACH pro-
tocol, the CH sends the data to the sink using the other
CHs as relay stations [6]. In this protocol, the problem
with CHs that are away from the base station, where they
were consuming huge amounts of energy during data
transmissions, has been solved.
2.4.4. V-L EACH
In the new Version of LEACH protocol, in addition to
having a CH in the cluster, there is a vice-CH that takes
the role of the CH when the CH dies [7]. When a CH
dies, the cluster become useless, because the information
collected by the node members will not reach the sink.
2.4.5. LEACH-C
LEACH has no knowledge about the CHs places. How-
ever, Centralised LEACH protocol can produce better
performance by distributing the cluster heads throughout
the network. During the set-up phase, each node sends to
the sink its remaining energy an d location. The sink then
runs a centralised cluster formation algorithm to deter-
mine the clusters fo r that round. However, since th is pro-
tocol requires location information for all sensors in the
network (normally p rovided by GPS), it is not robust [8].
2.5. Directed Diffusion
Directed diffusion is data-centric routing protocol for
collecting and publishing the information in WSNs. It
has been developed to address the requirement of data
flowing from the sink toward the sensors, i.e., when the
sink requests particular information from these sensors
[9]. Its main objective is extending the network life time
by realising essential energy saving . In order to fulfil this
objective, it has to keep the interactions among the nodes
within a limited environment by message exchanging.
Localised interaction that provides multi-path delivery is
a unique feature of this protocol. This unique feature,
with the ability of the nodes to respond to the queries of
the sink, results in con s iderable energy savings [10].
In order to construct the route between the sink (in-
quirer) and the sensors that interest to the sink’s request,
there are four stages; (A) interest propagation, (B) gradi-
ent setup, (C) reinforcement, and (D) data delivery. Be-
low is a detailed description for each stage:
1) Interest propagation: when a sink detects an event,
it initiates the interest messages and floods them to all
nodes in the network. These messages are exploratory
messages indicating the nodes with matching data for the
specific task. During this stage, the sink periodically
broadcasts the interest message. Once the interest mes-
sage is received, each sensor node saves it in an interest
cache. After that, the nodes flood this message to the
other nodes until the node that is interested in this inter-
est message; see Figure 2(a).
2) Gradient setup: based on local rules, different tech-
niques are used in gradient setup. For example, the nodes
with highest remaining energy could be chosen when
setting up the gradient. During the interest propagation
through the network, the gradients from source back to
sink will be setup. A node becomes a source node if its
observation matches the interest message and sends its
data through the gradient path back to the sink as shown
in Figure 2(b).
3) Reinforcement: during the gradient setup phase,
many paths have formed from the source to the sink. This
means the source can send the data to the sink through
multiple routes. However, as shown in Figure 2(c), the
sink reinforces one specific path by resending the same
interest through the specified path, which is chosen based
on many rules, like the b est link quality, number of pack -
ets received from a neighbour, or lowest delay. Along
this path, each node just forwards the reinforcement to its
next hop [10]. Finally, during this phase, the sink could
select multiple paths in ord er to provide multi-path deliv -
ery.
Copyright © 2012 SciRes. WSN
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Copyright © 2012 SciRes. WSN
68
Figure 2. Operation of the directed diffusion protocol.
4) Data delivery: after the reinforcement phase, as
shown in Figure 2(d), the route between the source and
the sink has been constructed and the data is ready for
transmission. As a result, we can say the Directed Diffu-
sion is characterised by these following specifications
[11,12]:
It requires neither a global node addressing mecha-
nism nor a global network topology. Moreover, the
routes are formed only when there is an interest. As a
result, it achieves energy efficiency.
In order to satisfy the user’s requests, network routes
are changed according to sensor reading changes.
The nodes that have matching information are only
the nodes that involved in the information generation.
2.5.1. Advantages of Directed Diffusion
It is designed to retrieve data aggregates from a single
node.
It mostly selects a specific route for the interest.
Hence, it decreases the energy consumption in the
network.
Data is named by attributed-value pairs.
It works well in multipurpose wireless sensor net-
works and in sensor networks that query, for example,
“GIVE ME THE TEMPERATURE IN PARTICU-
LAR AREA” or “WHO CAN SEE THE BLACK
COW”.
2.5.2. Disadva nt ages of Di rected Dif fus ion
It is, generally, based on a flat topology. Hence, scal-
ability and congestion (especially in the nodes that
near to the sink) problems exist.
An overhead problem occurs at the sensors during the
matching process for data and queries.
Unlike other routing algorithms, in Directed Diffu-
sion more than one sink can make queries and receive
data at the same time; hence, simultaneous queries
could be handled inside a single network.
In Directed Diffusion, the initial interest contains a
low data rate. However, an important overhead is
caused during flooding operation of interest propaga-
tion phas e.
The interests/queries are issued by the sink not by the
sources, and only when there is a request. Moreover,
all communication is neighbour-to-neighbour, which
removes the need for addressing and permits each
node to aggregate data. As a result, both points con-
tribute to reduce energy consumption.
Due to the flooding required to propagate the interest
on each node, it is not optimised for energy efficiency
and need high amounts of memory to store interest
gradients and received messages.
It mostly selects the shortest path between the source
and the destination, which leads to quick death of
It provides application-dependent routes based on the
interests of the user.
A. NOROUZI ET AL. 69
nodes on that path [12].
Finally, Directed Diffusion is a query-based protocol.
It may be not work well in applications where con-
tinuous data transfers are required (dynamic applica-
tions); for instance, environmental monitoring appli-
cations.
2.6 Gossiping Protocol
Gossiping is data-relay protocol, and, like Flooding pro-
tocol, does not need routing tables and topology mainte-
nance. It was produced as an enhancement for Flooding
and to overcome the drawbacks of Flooding, i.e., implo-
sion. In Flooding, a node broadcasts the data to the all of
its neighbours even if the received node has just received
the same data from another node. The broadcasting will
continue until the data is received by the destination [11].
However, in Gossiping, a node randomly chooses one of
its neighbours to forward the packet to, and once the se-
lected neighbour node receives the packet, it chooses, in
turn, another random neighbour and forwards the packet
to them. This process will continue until the destination
or number of hops has been exceeded. As a result, only
the selected nodes/neighbours will forward the received
packet to the sink. Unlike Flooding, Gossiping serves well
at one-to-one communication scenarios but it does not at
one-to-many. Packet forwarding mechanisms for both
Flooding and Gossiping are shown in Figure 3 [13] .
The main objective of Gossiping was reducing the
power consumption and keeping the routing system as
Figure 3. Forwarding mechanisms of both flooding and
gossiping.
simple as possible. However, it suffers from the latency
caused by the data propag ation. The power consumed by
Gossiping [14], is approximately equ a l to
O (KL)
K: Number of nodes that forward the packet.
L: Number of hops before the forwarding stops.
The most considerable feature of Gossiping is the abil-
ity of controlling the power consumption by selecting
appropriate K and L.
2.6.1. Advantages of Gossiping
It is very simple and does not need any routing table
and topology maintenance. So, it consumes little en-
ergy.
It appeared as an enhancement to overcome the im-
plosion that exists in Flooding.
In Gossiping, only the selected nodes contribute in
forwarding the data to th e sink.
It works well in applications that need one-to-one
commu ni c ation but it do es not in o ne- to-many.
2.6.2. Dis adv a nta ges of Gossiping
The next hop neighbour is randomly chosen, which
means it may include the source itself.
The packet will travel through these selected neigh-
bours until it reaches the sink or number of hops ex-
ceeds
It suffers from packet loss.
The remarkable disadvantage of Gossiping is suffer-
ing from latency caused by data propagation.
2.6.3. Improvements in Gossiping
Finally, in order to enhance the Gossiping protocol, ma-
ny protocols have been produced as an extension. For
example FLOSSIPING, SGDF, LGOSSIPING and EL-
GOSSIPING.
2.6.3. 1. FLOSSIP ING Protoc ol
It combines the approaches of both flooding and the gos-
siping routing protocols. When a node has a packet to
send, it decides a threshold and saves it in the packet
header, then randomly selects a neighbour to send the
packet to in Gossiping mode, while the other neighbour
nodes listen to this packet and generate a random number.
The neighbours whose generated random numbers are
smaller than the threshold will broadcast the packet in
Flooding mode. As a result, Flossiping improves the
packet overhead in Flooding and the delay issue in the
Gossiping [13].
2.6.3.2. SG DF Protocol
Single Gossiping with Directional Flooding routing pro-
tocol divided into two phases; Network Topology Ini-
tialisation and Routing Scheme. In the first phase, each
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70
node generates a gradient (shows number of hops to the
sink). In the second phase, in order to deliver the packet,
SGDF uses single gossiping and directional flooding
routing schemes. As a result in Figure 4, SGDF achieves
high packet delivery ratio, low message complexity, and
short packet delay [13].
2.6.3. 3. LGOSSIPING Protocol [15]
In Location based Gossiping protocol, when a node has
an event to send, it randomly chooses a neighbour node
in its transmission radius. Once the neighbour node re-
ceives this event, it, in turn, randomly chooses another
node within its transmission radius and sends it. This
process will continue until th e sink. As a result, the delay
problem has been solved to some extent. Figure 5 shows
the main objective of LGOSSIPING.
2.6.3.4 ELGOSSIPING Protocol [16]
In ELGOSSIPING protocol, when a node detects an event
and want to send, it selects a neighbour node within its
transmission radius and the lowest distance to the base
station/sink. Once the neighbour node receives the event,
it, in turn, selects another neighbour nod e within its tran-
smission radius and also the lowest distance to the sink.
The event will travel in the same way until the sink. As a
result, the problem of the latency and situation of non-
reaching packets has been solved to some extent. See
Figure 6.
2.7. Energy Efficient Sensor Routing Protocol
Energy-Efficient Sensor Routing (EESR) is a flat routing
algorithm [17] proposed especially to reduce the energy
consumption and data latency, and to provide scalability
in the WSN. Mainly, it consists of Gateway, Base Station,
Manager Nodes, and Sensor Nodes [18]. Their duties are:
- Gateway: Deliver messages from Manager Nodes or
form other networks to the Base Station.
Figure 4. Routing scenario in SGDF.
Figure 5. Schematic of data routing in LGOSSIPING.
Figure 6. Routing in ELGOSSIPING.
- Base Station: Has extra specifications compared to
normal sensor nodes. It sends and receives messages
to/from the Gateway. Moreover, it sends queries and
collect data to/from sensor nodes.
- Manager Nodes and Sensor Nodes: Collect data from
the environment and send it to each other in 1-Hop
distance until the Base Station.
Application area is divided based on the 2-dimension al
(x, y) coordinates into four quadrants; (+ +), (+ –), (– –),
and (– +), and the Base Station is located in the centre (at
coordinate). Furthermore, each quadrant, in turn, is di-
vided into sectors, locating the Base Station in the middle,
their numbers determined by minimum hops required to
deliver a message from the base station to the farthest
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A. NOROUZI ET AL. 71
position in the quadrant. Manager Nodes are located
(predetermined) in the centre of each sector on the di-
agonal line of the quadrant with 1-hop distance between
each other. Finally, the other nodes are randomly distrib-
uted in the application area; see Figure 7 [17].
As shown in Figure 7, each quadrant has three sectors
because the Base Station can communicate with the fur-
thest node in a minimum of 3-hops. Each sector has its
own ID, gathered it from Base Station, determined by the
quadrant name and the distance from the base station.
For example, 1-hop distance sectors names are (+1 +1)
sector, (+1 –1) sector, (–1 – 1) sector, and (–1 +1 ) sector.
Each sensor node constructs its EESR table, as shown
in Table 1, by broadcasting a “HELLO” message within
1-hop neighbour. The table contains distance from the
base station, Quadrant Names, Sector ID and Manager
Node Names.
2.7.1. The Algorithm
After the nodes are deployed, the Base Station sends the
relative direction information and sector ID of each node,
then each node constructs its EESR table. Once a node
detects an event, in order to select the next node to de-
liver the event, it investigates the sector ID of all neigh-
bour nodes within 1-hop in its EESR table. The node
selects its next node in one of these three procedures:
If a Manager node is within 1-hop distance, it will be
the next hop.
Figure 7. Locations of the nodes based on 2-dimensional (x, y)
Coordinates.
Table 1. Quadrant names, sector ID, and manager node
names.
Distance from
the base stationQuadrant nameSector ID Manager Node name
(+ +) (+1+1)sector +1 +1M.N
(+ –) (+1 –1)sector +1 – 1M.N
(– –) (–1 –1)sector –1 –1M.N
1 hop
(– +) (–1 +1)sector –1 +1M.N
(+ +) (+2 +2)sector +2 +2M.N
(+ –) (+2 –2)sector +2 –2M.N
(– –) (–2 –2)sector –2 –2M.N
2 hop
(– +) (–2 +2)sector –2 +2M.N
(+ +) (+3 +3)sector +3 +3M.N
(+ –) (+3 –3)sector +3 –3M.N
(– –) (–3 –3)sector –3 –3M.N
3 hop
(– +) (–3 +3)sector –3 +3M.N
If there is no Manager node, it will check for a normal
1-hop distance node that exists on the same sector to
be the next hop.
Otherwise it will look to another node that lies out of
its sector but close to the Base Station to be the next
hop. The nodes that lie on the same quadrant are the
preferr ed ones
After selecting its next neighbour node, the first node
will send the event only to this selected node. Once the
selected node receives the event, it, in turn, repeats the
same procedure to select its next 1-hop and send the
event. This process will continue until the Base Station
receives the event. However, if a Manager Node receives
the event, the event will transmit from manager-manag er
until the Base Station [17].
2.7.2. Advantage s o f EESR
It divides the application area into sectors; hence, it is
scalable.
It energy-efficient and achieves this feature in three
ways: firstly, it sends the event to the just one node
and does not flood it; secondly, Manager Nodes relay
the data in a predefined shortest path; and finally, af-
ter sending the first event, normal nodes will easily
select the next node by using their EESR tables. As a
result, it consumes little energy and prolongs the
network life time.
It uses one-on e commun icatio n . More ov er, af ter send-
ing the first event, the next hop will be found easily.
As a result, it is low latency.
In order not to send the data through a same route and
exhaust energy of these nodes, sometimes, it chooses
other routes to deliver the data.
2.7.3. Disadvantages of EESR
All 1-hop nodes of the event detected node could be
out of it transmission range. So, it ha s no specific cri-
terion to select the next node [19].
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72
If a node located in the furthest sector detects an
event and the next hop is located in the lower sector,
the data will be lost in the case where the lower
node’s e nergy has ha d finished.
If the normal nodes that are lo cated in the furthest sec-
tor detect an event and accidently every time their
next hop is a Manager Node, the energy of these Ma-
nager Nodes will exhaust earlier, because they will send
the event manager-manager until th e Base Station.
There is no balance in energy consumption, i.e., some
nodes consume their energy before other nodes.
2.7.4. Improvement of EESR
Due to these drawbacks, I proposed a new optimal rout-
ing algorithm in EESR by creating concentric sectors.
Our first Solution: is increasing number of the High-
ways (diagonals) in each quadrant as shown in Figure 8.
In this solution, the second and th e third problems (men-
tioned above in the disadvantages of EESR) have been
solved. However, the first problem is the most important
issue that needs to be solved.
Our second Solution: is fairly determining a number
of relay nod es (Manager Nodes) in each secto regardless
of the highways, as shown in Figure 8. In this solution,
the first and the last problems have been solved [19].
The routing process of this enhancement protocol is as
shown in the following flow chat in Figure 9.
3. Comparison of Explored Routing Protocols
During this research, many differences have been ob-
served, generally between flat and hierarchical routing
protocols and, precisely, among these researched routing
protocols. When compared to the other protocols, Gos-
siping is very simple and does not need any routing table
Figure 9. Rely nodes in each sector.
or topology management. It provides very high connec-
tivity, where as soon as a node becomes aware of its
neighbours it is able to send and forward packets. Gos-
siping protocol is based on the flooding protocol. Instead
of broadcasting each packet to all neighbours, the packet
is sent randomly to a single neighbour, meaning only one
copy of a packet is in transit at any one time. Having
received the packet, the neighbour chooses another ran-
dom node to send it to. However, this can include the
node which sent the packet itself. This process continues
until the packet reaches its destination or the maximum
hop count of the packet is exceeded. As a result, com-
pared to LEACH, Directed Diffusion nor EESR Proto-
cols, Gossiping uses a medium amount of power and it
appears to evaluate the improvements over Flooding, not
over LEACH, Directed Diffusion and EESR. Gossiping,
compared to other Protocols, suffers from quite high la-
tency because of the data propagation through network
(one to one communication) and the hop count could
become quite large due to the random nature of the pro-
tocol. As the number of nodes in a network increases, the
number of paths that a packet can follow increases. On
average, the number of hops taken to traverse the net-
work increases. Hence, packets are dropped when the
packets hop count reaches a maximum value. In larger
networks it is more likely that a packet’s hop count will
reach this value and so more packets are dropped. In
smaller networks, roughly half of the packets sent are
lost, and in larger networks the loss rate increases drasti-
cally. As a result, the Gossiping protocol is the worst
protocol in terms of loss of data packets. Hence, Gossip-
ing is not Scalable like LEACH, Directed Diffusion and
EESR. As a result, we summarised all that was men-
tioned above in two tab les; Ta b l e 2 [20], shows a general
comparison of different routing approaches for flat and
hierarchical sensor networks, and Table 3 shows how
Figure 8. Network with 16 highways.
Copyright © 2012 SciRes. WSN
A. NOROUZI ET AL.
Copyright © 2012 SciRes. WSN
73
lat and hierarchical routing protocols.
Hierarchical Routing
Table 2. General comparison between f
Flat Routing
Reservation-based scheduling sed scheduling Contention-ba
Collisions avoided Collision overhead present
Reduced duty cycle due to periodic sleeping ollin g sleep time of nodes
neighbours
onisation
he network ransmission
n traffic patterns
ontrolled
Variable duty cycle by contr
Data aggregation by cluster-head Node on multi-hop path a ggregates incoming data from
Simple but non-o p t imal routing Routing can be made optimal but with an added complexity.
Requires global and local synchrLinks formed on the fly without synchronisation
Overhead of cluster formation throughout tRoutes formed only in regio n s that have data for t
Lower latency as multiple hops network formed by
cluster—heads always available
Energy dissip ation is uniform
Latency in waking up intermedia te nodes
and setting up the multipath
Energy dissipation depends o
Energy dissipation cannot be cEnergy dissipation adapts to traffic pattern
Fair channel allocation Fairness not guaranteed
Table 3. Comparison between LEACH, directed diffusion and gossiping routing protocols.
LEACH Directed Diffusion Gossiping EESR
Class Hierarchical Flat Flat Flat
Scalability es the nodes into Limited lat topology nature) Limited lat topology nature) es application area to
High
(Divid
clusters) (Due to f(Due to f
High
(Divid
sectors)
Life Time
d , most of the Good nd-based andneighbour-Medium from high latency)
Very Good etermined
Energy YES e-hop routing fr om
YES y selects a specific route Medium LEACH or EESR. d
YES ds only to 1- h op s differ-
Data tion YES ggregated by CHs) node aggregate data then
NO nodes that participate in YES
Negotiation- NO ording to signal YES tiation is done during de randomly selects a YES ructing EESR table
se YES YES NO NO
Hop Comm. Single-Hop d CH-BS)
Hop to BS through i-Hop S through Multi-Hop -hop till B.S.)
Optimal ber has one chance orcement phase) domly select) time checks its EESR
Latency directly sends its data High the flooding during Very High propaga tion) erhead, and after the first
Throughput Very high nd only on e node Acceptable Low o the high delay) t optimum path, no delay,
Overhead (CH aggregates the data
of many nodes)
YES
(Overhead during the matching
process for dat a and queries)
NO
(it sends to a neighbour
node directly)
NO
(One to one communication)
Very Goo
(Due to TDMA
sensors are in s leep mode and
distributing the role of CH to
other nodes)
(Dema
neighbour Communication) (It suffers(Due to pred
allocation of M.N.
and using sectors)
efficient (Singl
node to cluster head)
(mostl
for the interest and routes are
formed only when there is an
interest)
YES
(Not like
However, no routing table an
topology maintenance)
(It sen
neighbours and choose
ent routes to deliver data)
aggrega (data a(each
relay it to the next hop)
(The
data delivery are just relay
stations)
NO
based
Recour
(Acc
strength) (Nego
Gradient setup phase) (A no
neighbour node to send) (const
finding the optimum route)
Awareness
(Member-CH an
Multi-
(From source
other nodes)
YES
Mult
(From source t o B
other nodes)
NO
(Each time 1
Route
NO
(Mem
relay to CH)
Little
(Reinf (Ran
YES
(Every
table to find better Sector ID)
Little
(Node
to CH) (due to
interest propagation) (Due to data(No ov
event, the next hop will be
found easily)
High
(No delay a
accesses the channel at a time)
NO
(Due t(Selec
no overhead)
A. NOROUZI ET AL.
74
Continued
(Only when an event occurs
does the sensor detect it) user only when there is a
request)
(only when an event occur
the sensor detect it) (Only when an event occur
the sensor detect it)
-based Event-based Query-based
(The queries are issued by the Event-based Event-based
Applications t
occurs a node detect it) ake
e data at
d
network initialisation
nitoring, i.e.,
ation
Monitoring app.
(Dynamic app. -If an even
Multi-purposes
Applications
(more than one sink can m
queries and receiv
the same time)
Application need
(one-to-one communication)Monitoring app.
(Dynamic app.)
App. Type Health monitoring
(artificial Retina) Environmental monitoring
(PODS Hawaii)
Environmental monitoring or
during deployment phase anEnvironmental mo
Agricultural applic
these researrotocols (L
Diffusion, GSR) fit und
ories and also compares these routing techniques ac-
in order to enhance the draw-
ba
e
be
. However,
th
of many events to the main sta-
tio
lay of delivering the packets to the Base
St
d by a limited ca-
pacity of batteries. Because of the power management
acti
dynhese essential prope ad-
ditional challenges to the communication protocols. In
this article we studied the operation of routing protocols
umption and discussed impact fac-
uary 2000. doi:10.1109/HICSS.2000.926982
ched routing
ossiping and EE
pEACH, Dire
er different cate-
cted
g
cording to many metrics.
With some changes in Gossiping Protocol, we can de-
crease the energy consumption and also increase Net-
work lifetime. Therefore,
cks of Gossiping Protocol, many new protocols have
been proposed as an extension for Gossiping: for exam-
ple, Flossiping, SGDF, LGossiping and ELGossiping:
Flossiping combines the two protocols of Flooding
and Gossiping. In this protocol, the overheads that exist
in the flooding and the delays th at exist in gossip ing hav
en improved. However, the power consumption and
packet delay time in this protocol are the same as the
flooding and the gossiping routing protocols.
(SGDF) Single Gossiping with Directional Flooding
routing protocol achieves high packet delivery ratio, low
message complexity, and short packet delay
e ill side effect of this protocol is that the amount of
packets becomes larger during packet delivery because of
the directional flooding.
LGossiping Although in this protocol the delay prob-
lem has been solved to some extent, there is still the
problem of non-reaching
n. Moreover, this protocol uses GPS to determine the
location of each nod e. Hence, additional h ardware means
extra money.
ELGossiping is proposed to improve the LGossiping
protocol. It has improved the network life time and has
solved the de
ation and non-reaching packets to some extent, but not
completely. In this protocol, two important metrics have
been exploited: energy and distance to the base station;
and in this way, when a node detects an event within its
transmission range, it sends the data to a neighbour node
that has lower distance to the sink.
4. Conclusion
Wireless Sensor Networks are powere
vities of these sensor nod
amically changes. Tes, the network topology
rties pose
with safe energy cons
tors in energy optimisation. With a little care in Gossip-
ing protocol we can find that by making some changes in
choosing of the next hop, the network lifetime can be
increased.
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