# Efficient Next-Hop Selection in Multi-Hop Routing for IoT Enabled Wireless Sensor Networks
## 2 Related Work
Finally, an introduced mechanism is implemented to decrease the energy utilization of distant communications. To select the centroid position, the protocol considers the remaining battery power of the nodes [23]. In [24], [PERSON] et al. present an energy-balanced clustered routing (EBCR) scheme for WSN based on the LEACH to maintain the structure of the cluster in K phases. In LEACH, \(CH\) is selected in the first phase. It involves energy prediction in the \(k-1\) phase, balancing the energy of the nodes, and determining the average energy of the nodes through residual energy. \(N\) is the number of nodes, \(E_{i-rest}\) is the residual energy of \(i\)th node and \(E_{average}\) is the average energy of nodes, as defined in (5). \[E_{average}=\frac{1}{N}\sum_{i-1}^{N}E_{i-rest} \tag{5}\]  
Variance of residual energy represented as \(S^{2}_{average}\) is given in (6), where the square of difference for \(E_{i-rest}\) and \(E_{average}\) is taken for all \(N\) nodes. Finally, all of these values are added and then divided by \(N\) to take the average. \[S_{average}^{2}=\frac{1}{N}\sum_{i-1}^{N}{(E_{i-rest}-E_{average})^{2}} \tag{6}\]  
This scheme efficiently enhances the lifetime of the nodes and also maximizes the network lifetime [24]. [PERSON] et al. present an uneven cluster-based energy-efficient routing protocol to balance the load at multiple layers. In each cluster, a distributed \(CH\) rotation-based mechanism is utilized to balance energy dissipation, and a multi-hop routing algorithm is used for distance-based routing between \(CH\) to BS. In inter cluster-based data packet transmission, the presented work considered two factors based on the distance to the \(CH\) node and residual energy. In \(K\)th layer, \(i\) is the \(CH\) node and \(j\) is a neighboring node to \(i\) in \((K-1)\)th layer. \(d_{i,j}\) is distance to \(CH\) nodes, and residual energy of \(j\) is denoted by \(E_{j}\). Cost of each \(CH\) node is as shown in (7). \[Cost_{i,j}=\left\{ \begin{array}{ll}\frac{e_{j}d_{i,j}^{2}}{E_{j}}\ d<d_{o}\\ \frac{e_{mgd_{i,j}^{4}}}{E_{j}}\ d\geq d_{o}\end{array} \right. \tag{7}\]  
In [25], the power-efficient data-gathering and aggregation protocol (PEDAP) was based on a near-optimal spanning tree model to achieve better lifetime of the network. In [26], the localized PEDP scheme used a localized and distributed architecture, whereas other schemes discussed here use a centralized approach. In [27], the power-efficient gathering in sensor information systems (PEGASIS) considers only the nearby neighbors for transmitting the packets towards the BS. It improves the cost as compared to LEACH. In [28], a delay-aware data collection network structure (DADCNS), the prime focus is to identify the tracks that result in less delay for data collection. It adopts top-down and bottom-up approaches to construct a tree structure for managing the nodes as per the distances, rank and time delays. [PERSON] et al. presented dynamic packet transmission within a cluster. The \(CH\) node rotation is adjustable according to the situation. The uneven clusters efficiently minimize energy consumption to assist in the extension of network lifetime [29]. In the Energy-Efficient and Reliable Routing (E\({}^{2}\)R\({}^{2}\)) scheme [30], the \(CH\) transmits the data by maintaining a certain throughput to ensure efficient utilization in single or multi-hop scenario. Moreover, alternative additional paths are also maintained for the selection of efficient routes. In [31], the authors minimize the energy consumption by balancing the routing cost by utilizing a multi-hop algorithm. The algorithm endures the failure of the head node and sensor nodes. The SEED algorithm minimizes redundant transmissions to attain efficient energy dissipation but cannot apply in the case of heterogeneous sensing device data. To overcome heterogeneous data trafficking and energy consumption between sensor nodes, another scheme was presented.