# REERP: A Region-Based Energy-Efficient Routing Protocol for IoT Wireless Sensor Networks
## 3 Proposed System Model
### REERP: Proposed Routing Protocol for Multi-Hop Transmission
Nodes in regions 3 and 4 are clustered, and thus, a few cluster leaders should be chosen to gather and broadcast to the BS a packet containing the data gathered by each member of the cluster. * **Election of CH:** This protocol is considered the most effective energy routing protocol that is used for different sensor networks. For choosing the CH in our proposed model, the execution is performed based on the SN's remaining energy and the average of all the nodes that belong to the same region. Assume that \(x_{i}\) are cluster heads of every node average probability; a node \(n_{i}\) is eligible only once to become a CH in every \(R_{i}=1/x_{i}\) iteration. Let us say that in case \(n_{i}\) is chosen as the CH in the first iteration \(R\), it will be again not selected as the cluster head for iteration \(R\) iterations. The threshold value will continue to fluctuate depending on the amount of energy remaining and the average energy of the region. When the network is uniform and each of the sensor nodes shares the same starting level of energy, an optimal proportion of nodes must be chosen as cluster heads. However, in a heterogeneous environment, every SN has a distinct \(R_{i}\), since each node has a different starting amount of energy. Additionally, sensor nodes with greater energy have much more iterations to aggregate at the head to prevent early death of normal nodes; as a result, all nodes die roughly at the same time. Here, \(M_{1,2}4\) is the set of sensor nodes in regions 2 and 3, with cluster heads \(n_{opt}\)\(M_{1,2}\) for each region. Figure 2: Proposed system model. The probability of \(n_{i}\) being the cluster head in every iteration is expressed in Equation (5):  
\[n_{i}=n_{opt}[1-E(R)-\frac{Ei(R)}{E(R)}]=n_{opt}\frac{Ei(R)}{E(R)} \tag{5}\]  
where \(E(R)\) is the mean energy per iteration of the region and \(E_{i}(R)\) is the remaining energy of node \(n_{i}\) in the \(n\)th iteration. The threshold value is evaluated in Equation (6):  
\[E(R)=\frac{1}{M_{1,2}}E_{sum}(1-R/TR) \tag{6}\]  
where \(E_{sum}\) is considered as the total energy of the region and \(TR\) indicates the overall lifetime of the network iterations. * **Steady Stage:** The energy dispersed by the SNs in each region is decisive and the total energy of the network is evaluated. To impose the dispersed energy, the equation is acquired in the equation. Every least energy acquired of all the sensor nodes in region 1 is denoted as \(E_{non-BS}\) that is transmitted in relaying some bits to sent to the base station is shown in Equation (7): \[E_{non-BS}=E_{trans}(numofclusters,dis_{BS})\] (7)  
Figure 3: Flowchart of proposed protocol. where \(dis_{BS}\) measures the distance between the same nodes present in Region 1 and the base station. The value of \(TR\) is computed in Equation (8):  
\[TR=\frac{E_{sum}}{E_{iterations}} \tag{8}\]  
where \(E_{iterations}\) signifies the energy dispersed in the region during each iteration, computed in Equation (9):  
\[E_{iterations}=S(2\times M_{1,2}E_{elect}+M_{1,2}E_{AD}+dis_{t_{0 BS}}^{4}+M_{1,2 \in fs}dis_{toclusterhead}^{2}) \tag{9}\]  
where \(S\) denotes message size, \(E_{elect}\) denotes energy utilization, \(E_{AD}\) denotes the energy used by each cluster head for data collection, \(dis_{t_{0 BS}}\) denotes the average distance between CH and BS, and \(dis_{toclusterhead}^{2}\) denotes the mean distance between CH and SN, as expressed in Equations (10) and (11):  
\[dis_{t_{0 BS}}=0.974M/2 \tag{10}\]  
\[dis_{toclusterhead}^{2}=\frac{M}{\sqrt{2\times\pi\times numberofclusters}} \tag{11}\]  
In the proposed model, the same technique as in the other protocols is utilized to choose CH. The threshold value and probability of each SN on which it relies is used to determine whether it is a CH. The heterogeneous nodes that did not cluster had previously \(\frac{1}{n_{hotovol}}\) iterations \(R\) in Region 3. \(H1_{0}\) denotes the collection of heterogeneous nodes that have not yet become the CH in the previous \(\frac{1}{n_{hotovol}}\) iterations \(R\) in region 4.