Analysis Of Leach Protocol In Wireless Sensor Networks.docx

Analysis of LEACH protocol in Wireless Sensor Networks Phan Thị Quỳnh Hương1, Lý Hữu Lộc 1, Đặng Anh Cường1 1Vietnam Korea University of Information and Communication Technology ptqhuong@vku udn vn, l[.]

Analysis of LEACH protocol in Wireless Sensor Networks

Phan Thị Quỳnh Hương1, Lý Hữu Lộc 1, Đặng Anh Cường1

1Vietnam Korea University of Information and Communication Technology ptqhuong@vku.udn.vn, loclh.21ce@vku.udn.vn,

cuongda.21ce@vku.udn.vn

Abstract Wireless Sensor Networks (WSNs) are distributed networks composed of

sensors and microsensors They consist of small, autonomous wireless sensor nodes deployed to collect and transmit data from the surrounding environment While WSNs offer numerous notable benefits, energy conservation poses significant challenges Data transmission within WSNs consumes energy, directly impacting the network's lifespan In recent years, efforts have been made to minimize energy consumption in WSNs through various algorithmic protocols, including the Low Energy Adaptive Clustering Hierarchy (LEACH) protocol This article focuses on implementing and analyzing LEACH, as well as proposing a variant of the LEACH protocol We simulate the LEACH protocol and its variant using MATLAB to assess the advantages and disadvantages of LEACH compared to its variant

Key word: wireless sensor network, variant of leach protocol, leach protcol,

energy-efficient protocols

Wireless Sensor Networks (WSNs) [1] are systems composed of a large number of sensor nodes with capabilities for data collection, computation, and communication These sensor nodes are deployed over a wide area and are typically connected to a base station WSNs have diverse real-world applications, including temperature monitoring, pressure sensing, disaster management, and forest fire tracking, among others

Figure 1: Description of Wireless Sensor Network

A Wireless sensor network consits of the following compents: Sensor node network, Base Station, User Station

1 User Staiton: It is requied to transmit data to base station throught the Internet and receive the data sent back by the base station

2 Base Station: Sending control commands or requests to the sensor node network via RS232 communication

3 Sensor node network: The sensor node network consists of numerous senor node, which are responsible for gathering information from the enviroment and transmitting it to the central node(Sink node)

Sensor nodes are low-cost electronic devices equipped with sensor node, a microcontroller,

a radio transceiver, memory and power unit The basic components of a sensor node are show in Figure 2 They can perform: computation, communication, and sending Bassically, they connect to each other via a wireless medium and collaborate to perform a certain taks [3]

Figure 2 Basic components of a sensor node

The architecture of a sensor node in Figure 2 consists of 3 main parts:

1 Sensing Unit: The Sensing Unit consists of Sensor and ADC Sensor gather

analog signals from the enviroment, which are then converted into digital from through an analog to digital converter (ADC)

2 Processing Unit: The Processing Unit receives data fro m the sensing unit and

performs computaion and analysis alogrithms

3 Communication Unit: The Communication Unit is responsible for facilitating

communication and data transmission through commonly used communcation protocols or any other suitable protocols

In most scenarisos, sensor nodes are randomly deployed with limited energy power The selection of routing techniques is an important issue for efficient delivery of sensed data from its source to the destination A lot of energy effiecent routing protocols have been

proposed and developed for WSN, depending on their application and network architecture One of the popular enerny-efficent routing protocols used in wireless sensor networks (WSNs) is the Low-Energy Adaptive Clustering Hierarchy (LEACH) protocol LEACH is dymatic clustering protocol in which sensor nodes organize themselves into clusters to reduce energy consumption

2 Classification of routing protocols in WSN

Routing protocols in wireless sensor networks (WSNs) are a set of rules, algorithms, and procedures designed to manage and determine routing paths for data transmission among sensor nodes in the network The objective of routing protocols is to optimize

communication performance, conserve energy, and ensure network reliability

Figure 3 Classification of routing protocols in WSN [4]

On the basis of Network Structure routing protocols in WSNs can be divided into location-based routing hierarchical-location-based routing, flat-location-based routing [4]:

1 Location based routing: In this protocol, each node in the network knows the

positions of all other nodes This allows the nodes to calculate the shortest from

the source to the destination Some popular location-based routing protocols

include: DSR (Dynamic Soucre Routing), AODV(Ad hoc On-Demand Distance Vector),…

2 Flat Based Routing: In this protocol, each node doesn’t know the positions of all

other nodes This means that nodes cannot calcutate the shortest from source to the destination Some flat based routing protocols include: Flooding, Routing by rumor,…

3 Hierarchal based routing: In this protocol, the network is divided into multiple

clusters, and each cluster has a designated node called the cluster head The cluster heads are responsible for transmitting data between the clusters Some hierarchal based routing protocols include: LEACH(Low Energy Adaptive

Clustering Hierarchy), TEEN(Threshold-sensitive Energy-Efficient Sensor

Network),…

LEACH (Low Energy Adaptive Clustering Hierarchy) is a wireless routing protocol used in WSNs LEACH is one of the most popular low- energy consumption routing protocol developed to prolong battery life and enhance network performance Leach protocol operation model is shown in Figure 4 The opreation of LEACH consists of many rounds where each round is divided into two phases: the set-up phase and the steady state phase [5]

Figure 4 Leach protocol operating model Set-up phase: in this phase, each sensor node in network participates in a Cluster Head

eleaction process by generating a random priority value between 0 and 1 If the generated

random number of a sensor node is less than a threshold value T(n) then that node becomes Cluster Head (CH) [5] The value of T(n) is calculated using Equation 1.

T (n )={1−P∗(P r mod 1

P)

if n ∈G

0if nG

(1)

Where P denotes the probability for a sensor node in the network to become a Cluster Head among all sensor nodes, r denotes the current round number, and G is the set of sensor nodes that have not participated in selecting a Cluster Head(CH) in the previous 1/P rounds A sensor node that become CH will not be able to participate in the next 1/P round In this way, every sensor node gets equal chance to become the Cluster Head and energy disipation among the sensor nodes is distributed uniformly [5] When a sensor node is selected as a Cluster Head, it sends a message to all non-Cluster Head nodes to join its cluster Depending on the signal strength to receive the message, the sensor nodes decide to join a

CH for current round and send a join message to this CH With each new round, the Cluster Heads rotate in circles to keep distribution balanced and evenly distribute the energy load in the sensor nodes Figure 5 illustrates this phase using flowchart

Figure 5 Flowchart of the set-up phase of the LEACH protocol Steady-state phase: in steady phase, the sensor node is a non-cluster head that collects data

and sends data through the cluster head The member sensors in each cluster can communicate only with the cluster head via a single hop transmission The cluster head aggregates all the collected data and forwards data to base station either directly or via other cluster head in network After a predefined time, the LEACH protocol operation returns to the set-up phase Figure 6 illustrates this phase using flowchart

Figure 6 Flowchar of the steady-state phase of the LEACH protocol

4 The Energy Model

A simple model for energy consumption was assumed, where the transmiiter dissipates energy to oprerate the radio electronics and the power amplifier, and the receiver dissipates energy to opreate the radio electronics as shown in the Figure 7

Figure 7: Radio disspation Model [6]

Energy consumed by any transmitter to send a k-bit message on a distance d on equation (2) and equation (3)

E transmittion={ k∗E electronic+k∗E fs∗d2, d <d o

k∗E electronic+k∗E amp∗d4, d ≥ d o (2)

d o=√ E fs

Where Eelec denotes the energy dissipated by radio disspation Efs is the energy dissipated in the amplifier while d ≤ do and Eamp is the energy disspated in the amplifier while d > do The Eelec depends on many factors such as digital coding, the modulation, the filltering, and the spreading of the signal [6], the use of free space (Efs) and multi-path (Eamp) fading channel models depends updon the transmission distance d If distance is less than a thresold, the free space model is used, otherwise the multi path model is used The energy dissipation during the packet reception is given by Equation (4):

E reception=k∗E elec (4) Additionally, data aggregation operation will consume the energy EDA

There are several variants of the LEACH protocol, and researchers have proposed various modification to address different challenges and optimize its performance This paper will propose two variants of the leach protocol, LEACH-C and MOD-LEACH

LEACH-C is centralized protocol [7] in which all decisions such as CH selection, energy

compulation, and information distribution are performed by Base Station (BS) The set-up phase of LEACH-C is similar to LEACH In the set-up phase, to create better cluster heads, energy should be uniformly distributed among all sensor nodes To achive this, the BS calculates the average energy of the sensor nodes afer each round, and nodes with energy lower than the average are prohibited from participating in the CH selection process for current round For nodes with energy higher thanh the average, they are allowed to participate in the CH selection process for the current round The average energy of the network Eave can be calculated by using Equation (5)

E ave=

∑

i=1

N

¿E i N

(5)

MOD-LEACH is Modified LEACH This main difference of this protocol compared to

LEACH is how to choose Cluster head, where at every new round, it changes the cluster head and it will nots get another chance o be chosen for next 1/p rounds MOD-LEACH introduces the “efficient cluster head replacement scheme” which is a threshold in cluster head formation Cluster head will remain cluster head for the next round as well if it has not spent much energy during its tenure and has residual energy higher than requied threshold

So, with this method it will save the energy wasted in routing packets of new cluster head and cluster formation But, it will be replace if it has energy less than required threshold [8]

6 Simulation settings and Result

6.1 Simulation settings

The simulation is carried out using MATLAB (R2019a) which simulates the sending, receiving, comparing, etc

The simulation assumed that there are sensor nodes are randomly and densely scattered in a two-demensional square filed, and the sensor network has the following properties:

 All nodes are stationary and randomly disposed

 The base station is fixed and located above all sensor nodes

 All nodes in the network are uniform and start with the same energy level

 Nodes always have data to send

 Transmission power varies depending upon the distance between node and receiver

Table 1 Summary of parameter setting

Number of nodes (n) 100 + 1 Base station (BS)

Energy disspation in reception (ERX) 50 nJ/bit

Energy disspation in transmission (ETX) 50 nJ/bit

Free-space amplifier paremeter (Efs) 10 pJ/bit/m2

Multipath maplifier paremeter (Emp) 0.0013 pJ/bit/m4

Data arregation energy (EDA) 5 nJ/bit/signal

The simulation was carried out in MATLAB (R2019a) and compared the LEACH protocol and the variant of the LEACH protocol, MOD-LEACH

Figure 8 demonstrates the wireless sensor network intialization for a homogeneous system The simulations were configured with a network size of 100 x 100 meters and with 200

nodes were randomly distributed; the base stations were located at positions 50 and 135.

“X” denotes Base Station

Figure 8 Arrangement of the nodes

Figure 9 represents the number of remaining nodes after 2000 rouds As shown in the figure,

we can observe the nodes dying It is eviden that the LEACH has a faster number of dead sensor nodes than the MOD-LEACH protocol

Figure 9 Number of node allive per round

Figure 10 depicts the number of packets sent from the Cluster Head to the Bast Station (BS) per round, it shown the total number of packets sent to the Base Station (BS) of the two protocols is quite equal in the first 1000 rounds However, after the first 1000 rounds, it clearly shows that the MOD-LEACH protocol sends more packets than the LEACH

protocol Mostly after 1000 rounds, the leach protocol has more dead nodes compared to MOD-LEACH, resulting in fewer Cluster Heads than its variant

Figure 10 Number of packets send to Base Station (BS)

Figure 11 illustrates the details of the dead nodde for the two protocols Here, we are comparing the first node’s dead nodes, ten percent dead nodes, and all dead nodes between the two protocols We observe that the number of dead nodes of the first node and ten percent dead node of the two procols is not too significant

Figure 11 A chart comparing the number of dead

However, when comparing all dead node of protocols, we can see the distince differences between the two protocols Table 3 will provide a more an accurate

Table 2 Comparison between different protocols

After simulating the LEACH protocol, we have identified the advantages and disadvantages

in wireless sensor networks

1 Concept of clustering used by LEACH protocol enforces less communication between sensor nodes and the BS, which increases the network lifetime

2 The LEACH protocol helps to distribute the workload among the nodes in the network, avoiding overload for signle sensor nodes

3 LEACH protocol gives equal chance to every sensor node to become the CH at least once and to become a member node many times throughout its lifetime This randomized rotation of the CH enhances the network lifetime

Disadvantages

1 In each round the CH is chosen randomly and the probability of becoming the CH is the same for each sensor node After the completion of some rounds, the probability

of sensor nodes with high energy, as well as low energy becoming the CH, is the same If the sensor node with less energy is chosen as the CH, then it dies quickly Therefore, the robustness of the network is affected and the lifetime of the network degrades

2 The cluster leader is chosen at random, so the membership of the clusters can change frequently during the network's life This constant change can lead to data loss and network instability

3 The LEACH protocol can be difficult in large-scale wireless sensor networks The process of selecting a random cluster head can become inefficient and increase the cost of network deployment

In this article, we have analyzed the LEACH protocol and proposed an improvement to the LEACH protocol based on the Cluster Head (CH) selection phase to achieve higher power efficiency in Wireless Sensor Networks WSN)

Although the simulation results confirmed that MOD-LEACH outperforms LEACH in finding the number of remaining member nodes in the cluster, the number of packets transmitted and the complexity of the environment will be studied next proceed in the future

References

[1] V Potdar, A Sharif and E Chang, "Wireless Sensor Networks: A Survey," 2009

International Conference on Advanced Information Networking and Applications Workshops, pp 393-422, 2009

[2] D S & G S Tomar, "Energy Efficient Multitier Random DEC Routing Protocols for

WSN: In Agricultural," Wireless Personal Communications, pp 727-747, 2021

[3] A K H & A.-S S Al-Shaikh, "Performance Comparison of LEACH and LEACH-C

Protocols in Wireless Sensor Networks," Journal of ICT Research and Applications,

vol 12, pp 219-236, 2018