Abstract—Even structure. In this form of protocol, the

Abstract—Even after sixteen years
of life, Low Energy Adaptive Clustering Hierarchy (LEACH) protocol is still
obtaining the expertise of the research network operating in the Wireless
Sensor network (WSN) discipline. Researchers have come up with diverse and
numerous modifications of the LEACH protocol. The struggle of long lifetime and
strict energy constrain brings a natural integration of energy harvesting into
wireless sensor networks. A modified low energy adaptive clustering hierarchy
(LEACH) protocol has been proposed to increase the network life time by energy
efficient cluster head selection. This paper surveys the Modified LEACH in
three distinct networks. The calculations and results will clearly give that
proposed Modified LEACH provide greater energy efficient and throughput.

Keywords—Clustering, Energy Efficient, Hierarchical Protocol, Routing, LEACH,
Heterogeneous wireless sensor networks, ZigBee, dead nodes, dominating set.

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?.   Introduction

Wireless Sensor Networks (WSN) is acting as a
rising need for mankind. Even though such networks are nevertheless in studies
section however, they have excessive capability to be carried out in nearly
each area of lifestyles. A Wireless Sensor network is a group of big numbers of
sensor nodes with confined sensing, computing and communication competencies.
Those sensors are deployed over large vicinity with one or multiple Base
Station (BS). WSN has huge software possibilities, inclusive of temperature, strain,
humidity and habitat tracking, disaster control, military reconnaissance,
forest fire-monitoring, protection surveillance and lots of more 1, 2, and
3. In maximum situations, sensor nodes are randomly deployed with restricted
battery strength. The selection of routing techniques is a vital problem for
the efficient delivery of sensed information from its source to destination.
The routing strategy utilized in those form of networks should make sure
minimal energy consumption as battery replacement in sensors are often not
viable. Depending at the networking software for WSN, a variety of
energy-efficient routing protocols were proposed and advanced. Designing a
routing protocol is complete of challenges, mainly due to limited energy, low
bandwidth, and low computational energy, no traditional addressing scheme,
computational overheads and self-corporation of the sensor nodes. Hierarchical
routing presents better energy efficiency and scalability due to its structure.
In this form of protocol, the entire network is divided into clusters and a few
nodes are selected as special nodes based totally on positive criteria. These
special nodes are called cluster heads (CHs) collect, collocate and compact the
records acquired from neighbor nodes, and subsequently transmit the compressed
data to the BS. The CH provides additional services to other nodes within the
cluster and therefore consumes greater energy in comparison to different nodes
of the cluster. Cluster rotation is a commonplace approach deployed to
stability the energy dissipation inside a cluster. The primary hierarchical
routing protocol was proposed by way of Heinzelman et al. 8 called LEACH. In
LEACH, clusters are formed on the basis of the strength of the sign obtained by
means of the sensor nodes. The nearby CHs are used as routers to the BS.
Several surveys 9, 10, 11, 12, 13 had been performed on LEACH.
However, LEACH does now not assure the location and range of CHs in every
round. As a result, higher energy dissipation occurs. Additionally, The CHs
which might be a ways away from the BS spend more energy results in energy

?.    A Review On Modified Leach

To conquer the problems of LEACH
protocol, Mahmood et al. 14 have proposed a brand new variation of it
referred to as modified LEACH (MOD-LEACH). In this Algorithm, it uses two
specific signal amplifications for intra and inter cluster communications. It
uses a low amplified sign for intra and an excessive amplified sign for inter
communications. In this way authors save a significant amount of energy,
whereas in LEACH for both forms of communication (intra and inter) the equal
signal amplification is used. One extra modification made through the authors
is in CH adjustments. Like LEACH, a similar CH selection set of rules is used
and a new CH is selected however no longer in every round. After the completion
of each round, the CH exams its residual energy. And if it is less than a
predefined energy threshold, the CH changes and new CH selection procedure
starts. If the residual energy is higher than the strength threshold, the CH
remains as CH for the next round. That is how energy consumption reduces: by
means of not selecting a brand new CH in every round. MOD-LEACH has changed in
primary weaker sections of LEACH: CH adjustments in each round and the use of
the equal amplification sign for inter and intra communications. It plays
higher in terms of energy consumption and network lifetime examine to LEACH.
One predominant problem of this protocol is the amplification of signals in
one-of-a-kind modes and their synchronization. Further, Singh et al. 15 have
stepped forward this protocol via the use of twin transmitting electricity
degree and green CH substitute schemes. The new protocol is known as Enhanced
Modified LEACH (EMOD-LEACH) and it performs higher in phrases of energy
consumption and network lifetime. This protocol is not suitable for
periodically sensing information in WSN. It can also lessen the statistics

?.    Zigbee
Network Using Modified Leach Protocol

Today, many
companies require a reliable Wireless sensor networks at much less value and
much less time for protection and tracking. ZigBee could be the right
preference that may meet those requirements 16. ZigBee well-known indicates
the capacity for use for lots programs that require low facts transmission and
low power consumption. ZigBee network is a combination of applications and
related gadgets. The Cluster tree topology is used here. The advantages of the
ZigBee tree routing is no route discovery overhead and occasional memory
consumption. The drawback of tree topology is if one of the parents will become
disabled, the children of the disabled determine cannot speak with other
gadgets inside the network. Despite the fact that nodes are geographically near
every other, they cannot communicate directly. The goal is to allow all of the
nodes inside the network work as long as feasible and distribute the task
lightly and to avoid having any lifeless node throughout the running mode.
Consequently, MOD- LEACH protocol is applied and modified transmission settings
to save energy. On this answer, the router should additionally be modified
periodically but each period ought to no longer be either too long or too
short. For every PAN (Personal Area Network), a random node will be picked as a
router first of all. Then the router could be changed primarily based on the
following protocol: First, each node generates a random number. If the node has
low energy, the generated wide variety may be zero. Second, each node will send
the generated variety to the cutting-edge router. Third, the modern router will
pick out the node that dispatched the biggest number to be a candidate destiny
router. At last, the candidate router takes the obligation of being the PAN router,
and the current router will become a regular node within the subsequent cycle.

Transmission Setting

In the Zigbee network the
author proposed three levels of power measurement (low, middle, high) to every

Here, one node in the network is assigned
to work as a router to collect all data from nodes and then send everything to
the destination.

This design will help the router to finish
the process quickly and assist the sender nodes to go into sleep mode earlier
while the assigned node works for transmission.

In addition, the system will
save power by minimizing the transmission time. It saves energy by using Safer


Fig. 1.Transmission setting for Zigbee Network

Power Management

The power evaluation is used to replace the
routing path in WAN. The information packet ought to deliver the path data to
the following router and also will be passed in addition to the following
router. Every PAN should work so long as viable through choosing the fine route
through the sink that coordinates the entire network. The sink analyses the
energy intake for every PAN. Then it will decide the routing route.Best the
variety of running nodes at low energy mode in every PAN is needed to do the
essential evaluation by the coordinator. The sink gets the power facts
(consists of the quantity of nodes that work at distinctive power levels (high, center, low),) from each
PAN. So it is used to calculate the remaining energy of every PAN. This
facilitates the sink to decide the exceptional path dependent on the used
routing protocol. The PAN with excessive last energy has greater risk to be
decided on with the aid of the sink. Having the three stages of power for each
node, we count on the subsequent:


High level: 80% or more of remaining power.

Mid-level: the remaining power between 30% and 80%.

Low level: the remaining power is less than 30%.

remaining power for any PAN is calculated based on the Percentage of the
remaining power of each node within that PAN 3:




Emax is the Maximum energy;

Emin is the Minimum energy;

h is the number of nodes at high-level power;

is the number of nodes at middle-level power;

is the number of nodes at a low-level power.

The maximum and minimum energy bounds
should be calculated for each PAN. Then the middle range is calculated as below:


Result analysis

The proposed measure can be helpful to
manage PANs based on the remaining power. The ZigBee
chip end result based totally on Xbee-seasoned 900; Battery capability is 3000
mAh. Node facts size is five bytes, and this facts is updated every 10 sec;3. The proposed transmission setting and modified LEACH conclude
that there were no early dead nodes since the emergency mode kept the PAN
working reliably as long as possible. When the time arrived at 480 hr. we
changed the batteries. Therefore, the whole PAN in modified LEACH protocol
could maintain longer regular working hours. Results show that our modified
LEACH Zigbee network had more efficient data transmission strategy and had a
longer reliable working period with less power consumption.

?.    Modified
Leach Protocol For Heterogeneous Wireless Networks

A modified low energy adaptive clustering
hierarchy (LEACH) protocol for Heterogeneous wireless network to boom the
Network life time is split into two principal levels are setup phase and steady
state phase. Setup section has been modified such that cluster head (CH)
selection can be decided on only from superior nodes. Network lifetime in
homogeneous networks is much less than heterogeneous networks. Especially
cluster heads devour greater energy than different normal nodes due to the fact
maximum CH energy goes in data aggregation from other nodes in cluster and
resend to sink node or base station. Here introduced modification to Setup section
in well-known LEACH so as to cause large development.

As a result network lifetime has been prolonged while proposed
modified LEACH is used. It will be greater efficient if Cluster heads chosen
from advanced nodes simplest as a way to increase CH lifetime and the complete
network as nicely. Right here in MOD-LEACH threshold value calculated via 5:





is the percentage of cluster nodes;

refers to the current number of rounds;

is the total number of nodes;

is the set of nodes that did not become cluster heads in the 1/p*a round;


By this way CH will be chosen from advanced
node mostly.

Fig. 2. Flow chart of Modified Leach Protocol 5


algorithm has been changed to assign CH only from advanced nodes set. Steady
state will continue to be the same as standard leach. All simulations 17 have
been made with assumption that heterogeneous nodes percentage is 10 % of
general range of nodes. Ultimately the modified LEACH is better than each
standard LEACH and EAMMH protocols. Modified LEACH of Heterogeneous WSN gives a
great improvement and excellent performance in terms of power intake and
growing the extent in lifetime of the heterogeneous Wireless sensor networks
than in well-known LEACH and EAMMH systems.

?.    Modified
Leach Protocol In Wireless Sensor Networks

Here with the aid of considering the difficulty that the network has
a restrained lifetime in the course of which nodes have restricted energy to
transmit the facts, Hein Zelman 8 proposed a Protocol, a new version of LEACH
which can further be applied in different clustering routing protocols for
better performance, an set of rules is modified so that each one the sensor
nodes have to be designed extraordinarily energy efficient. On this proposed
work, used the leach protocol in fixed zones and in last zones provided direct
communication to the base station. On this work, base station is located
outside the network and a doorway node is positioned at the center of the
network, in order that they have divided the whole network into four zones. The
node located within the quarter one is at once communicated to the bottom
station and the remaining nodes of the opposite region communicate to the bottom
station via doorway node. Here it is far shown that the proposed protocol carry
out better is than L. Leach. The L-Leach protocol network lifetime is round
1600 round and on this proposed protocol community life time is about 2500 round.


Simulation for Throughput vs. Number of rounds for MOD-LEACH vs. LEACH is shown

Simulations are
conducted using MATLAB (R2013b) and to get precise plots, condense
interval is taken. MATLAB programming platform is used for coding of LEACH and
proposed work Sensor nodes are deployed in random manner and made homogeneous
WSN using MATLAB4. The wireless channel
is used due to the fact the nodes deployed inside the network are communicating
wirelessly primarily based on their distance, transmission variety and many
others. Simulations show that proposed protocol performs better thinking about
metrics of throughput, network lifetime, and place of base station and initial energy
of sensor nodes. Thinking about the simulated results they deduce that, maximum energy is achieved by proposed work.


?.    Conclusion

This paper shows the survey of modified
leach protocols in three networks. It contains many advantages like it saves
much more energy and network lifetime. In this survey paper we present some
energy efficient hierarchal clustering routing protocols, developed from
conventional LEACH routing protocol. Main focus of our study is how these
extended routing protocols work in order to increase the life time and how
quality routing protocol is improved for the wireless sensor network.
Furthermore this paper also highlights some of the issues faced by LEACH and also
explains how these issues are tackled by extended versions of LEACH. We compare
the features and performance issues of MOD-LEACH hierarchal routing protocol.
In this survey paper we have discussed LEACH, MODIFIED LEACH for the ZIGBEE
of this survey is to examine the energy efficiency and throughput enhancement
of these routing protocols. We compare the lifetime and data delivery
characteristics with the help of analytical comparing.Modified LEACH of
Heterogeneous WSN gives a great improvement and excellent performance in terms
of power intake and growing the extent in lifetime of the heterogeneous
Wireless sensor networks. And the maximum energy is achieved in Wireless sensor
networks. Modified Leach used Zigbee network provides efficient data
transmission with longer reliable in less power consumption. Certainly further
energy improvement is possible in future work especially in optimal guaranteed
cluster-heads selection.

?.    Future Work

We can create the Modified Leach without
dead nodes by calculating distance between node to node and BS. We are able to
advantage on top of the line control approach by way of introducing the
proposed set of rules consisting of Machine Learning, Data Mining, Feedback
Response, etc. So we are able to in addition reduce the power
consumption in WAN (Wireless Area Network). The concept of sensor cloud is an
upcoming idea which makes it feasible to rent out a sensor deployment to
numerous users for one-of-a-kind application on demand.