**3.2 An extensive analysis of conventional hierarchal routing protocols**

In WSN the nodes are deployed densely, and some of them are placed too tightly which cause data redundancy when transmitting collected data to the base station. Therefore, the hierarchal routing protocol uses a clustering approach in order to lower the energy consumption by avoiding redundancy factor in the data transmission process. The clustering mechanism involves a cluster of nodes and cluster head selected according to node residual energy to forward the aggregated data from the clusters without processing redundant data. The following are some of the existing hierarchical routing protocols discussed [11, 12]:

CH node, it must contain higher energy than a non-CH node. In the LEACH protocol, the CH selection mechanism is constructed in such a way that CH can randomly change over time to balance the energy dissipation of the nodes and

• Formation of CH- The nodes in the cluster uses a random function to choose a number between 0 and 1. If the number found to be less than subsequent threshold value ν(x), then the node becomes the CH of the current cycle.

*θ=*1 � *θ* ∗ ð Þ *r* mod 1*=θ* : *fx* ∈*Y*

The above Eq. (2) demonstrates the computation of threshold value, where r is the number of cycle that has completed, x indicates the overall nodes in the network, θ indicates the percentage of the CH, and Y is the non-CH node. Here in this, each node can generate a random number between 0 and 1 and the node becomes CH when its number is found to be less than ν(ϰ), otherwise it will not become CH. Once the CH is selected using the Eq. (2), the CHs-node uses a non-aggressive Carrier-Sense-Multiple-Access (CSMA)-transmission protocol to broadcast the notification message to inform all the other nodes which have played a role for selecting CH in the current cycle. Now based on received signal strength (RSS) of the broadcast notification message, all the non-CH nodes identify that which cluster it belongs to. After each node verified to which cluster it belongs to, then the nodes must have notified to CH that it is a member of its cluster. Therefore the CH plays a role of local data-center to control the transmission of the data packets in its cluster. The CH then initiates TDMA to construct the schedule, then forwards this schedule to all nodes presented in the cluster to ensure that there are no conflicts between data and message transmissions. In order to save power, it also allows each node to put their radio components in a sleep mode outside of their data transmission job. Therefore, the setup phase is complete when all nodes in the cluster are aware of the

In this phase, the data transmission operation is executed in different frames. In

The LEACH protocol considers that cluster nodes start with the same energy and

the likelihood function with threshold value v(x) not recognizes the remaining power of each node. Therefore, the LEACH gets good reduction rate in energy utilization comparing to direct communication process and MTE routing protocols. However, LEACH distributes the similar-level power-loads to all nodes of clusters, and this will further result in an imbalance of node after running for a long time. Also, if a node with less energy is selected as the CH, the node may quickly drain its energy. If this happens then, the CH will terminate and lose their connectivity to all

this frame, the cluster node forwards its data to the CH node according to its transmission schedule. In order to preserve energy, each cluster node uses less power dissipation mechanism based on the RSS value of the CH broadcast notification message. Afterward, the CH receives all data from the cluster nodes and then performs the data aggregation operation and transmits resultant data to the sink

<sup>0</sup> : *Otherwise* ( ) (2)

thereby cluster nodes gets an opportunity to become CH in next cycle.

*υ*ð Þ¼ *x*

*Energy Saving Hierarchical Routing Protocol in WSN DOI: http://dx.doi.org/10.5772/intechopen.93595*

TDMA schedule, and the steady phase begins.

• Analysis of energy consumption in LEACH

ii. Steady-State Phase

nodes belonging to its cluster.

**159**

node (**Figure 3**).
