Leach routing protocol in WSN Lab 1 Networks and Communication Systems Department TA. Maram Almuhareb Leach routing protocol in WSN

Introduction LEACH stands for Low-Energy Adaptive Clustering Hierarchy This WSN is considered to be a dynamic clustering method LEACH has two phases

The Problem The reason we need network protocol such as LEACH is due to the fact that a node in the network is no longer useful when its battery dies This protocol allows us to space out the lifespan of the nodes, allowing it to do only the minimum work it needs to transmit data

The Cluster-Head The LEACH Network is made up of nodes, some of which are called cluster-heads The job of the cluster-head is to collect data from their surrounding nodes and pass it on to the base station LEACH is dynamic because the job of cluster-head rotates

LEACH’s Two Phases The LEACH network has two phases: the set-up phase and the steady-state The Set-Up Phase Where cluster-heads are chosen The Steady-State The cluster-head is maintained When data is transmitted between nodes

PROPOSED PROTOCOL We have analyzed a heterogeneous sensor network environment. There two types of nodes : Advanced node : have higher energy source Normal nodes: less energy source Where m is the percentage of advance and normal nodes having a times more energy than the normal nodes that are distributed randomly over the sensor field.

Stochastic Threshold Algorithm Cluster-heads can be chosen stochastically (randomly based) on this algorithm: If n < T(n), then that node becomes a cluster-head The algorithm is designed so that each node becomes a cluster-head at least once  Each node uses a stochastic algorithm at each round to determine whether it will become a cluster head in this round. In the approach, advanced nodes have higher probabilities to become a cluster head in a particular round than the normal nodes. 

An Example of a LEACH Network While neither of these diagrams is the optimum scenario, the second is better because the cluster- heads are spaced out and the network is more properly sectioned

LEACH Simulation on Matlab The proposed approach has been implemented in MATLAB and the performance has been evaluated by simulation. In this work, we have measured the lifetime of the network in terms of rounds when the first sensor node dies. Simulation Area in meter xm=100; ym=100; Number of Nodes in the field 200 Base Station Location x and y Coordinates of the Sink (150,50) Initial Energy of sensor in Joul 0.1 Optimal Election Probability of a node to become cluster head 0.2 maximum number of rounds 50 The following set of results represent the simulation of both LEACH at 0.2 probability that is the percentage of total nodes which can become cluster head is 20% of the total number of nodes. Table 1: Various parameters and their values

Simulation parameter

Setup Phase when cluster are being created, each node decides whether or not to become a cluster-head for the current round

Data Transmission Phase Once the clusters are created, the sensor nodes are allotted timeslots to send the data. Assuming nodes always have data to send, they transmit it at their allotted time interval. When a node receives data from one its neighbors, it aggregates it with its own data

Simulation and Analysis of Results The parameters taken into consideration while evaluating EAMMH and LEACH are as follows: Round Number vs Number of Dead Nodes (with variation of round number ) Round Number vs Average Energy of Each node (with variation of round number )

Simulation result Figure 1: 200 Node Figure 1 is showing the WSN in active mode with active as well as with some dead nodes represented by yellow triangle . As it is Leach so all nodes represented by circles are normal nodes and nodes with circle and and all nodes represented by plus (+) are advance nodes and with star(*) are cluster heads. the blue lines which are representing the different clusters and each has its CH Figure 1: 200 Node

Simulation result Figure 2: 25 Rounds Figure 3: 50 Rounds

Simulation result Figure 4: 25 Rounds Figure 5: 50 Rounds

Analyses of Results It is observed from the figures 2 and 3 ,that as time progress LEACH lose energy as the number of round increases. Is also observed that once a node reaches the value of zero it is no longer functional and is deemed as a dead node Figures 4 and 5 represents the number of dead nodes against the round number elapsed for 25,50 rounds we can observe that after a total of 25 rounds the number of dead nodes resulting from LEACH protocol is incresed

Conclusion From the brief analyses of the simulation we have come to a conclusion that LEACH can be preferred in cases of smaller networks where the total number of nodes is less than fifty

References N. Sehgal , G. Kaur “Improved Cluster Head Selection Using Enhanced LEACH Protocol” LEACH Code https://www.mathworks.com/matlabcentral/fileexc hange/44073-low-energy-adaptive-clustering- hierarchy-protocol--leach-?s_tid=srchtitle