# Efficient Next-Hop Selection in Multi-Hop Routing for IoT Enabled Wireless Sensor Networks
## 3 System Model and Problem Identification  
In the literature, we found several related research studies for data aggregation that discussed different models with limitations such as energy efficiency and scalability. We observed a few problems in the delay-aware network model for the collection of data, where a single cluster is divided into sub-clusters and the remaining nodes are considered as member nodes. The model reduces the delay, but its structure is fixed. Therefore, it can only be applied in homogeneous WSNs. Researchers most probably work in homogenous networks, where all nodes have the same features such as residual energy, processing capability, and communication units. Conversely, for heterogeneous networks, these models vary because of the mobility, localization and trajectory management. In this context, every node does not have a fixed position, and in multivendor sensor-based networks, every sensing device has distinct features. This affects the packet delivery ratio, delay, energy consumption and available time slots that can be considered as decision variables as per the feasibility constraints for routing protocols to evaluate the performance.  
The energy consumption for data exchange varies due to adoption of different types of small and large routing tracks. An efficient information collecting scheme for a hybrid network is needed to attain performance in heterogeneous systems with hierarchy-based energy-efficient routing paths. In the base paper, it is assumed that resources for sensor nodes are the same throughout the network. We present a system model where \(CH\) acts as a collector node to receive data from member nodes. In this model, a number of expired nodes are also considered, as shown in Figure 1. The energy of nodes decreases at a variable rate with time because each node receives and transmits several data packets at various distances. This results in high energy consumption and reduces the network lifetime. At the time of network creation, every node has an equal energy level of E = 100 \(\mu\)Joule.  
Figure 2a illustrates the network state after a specific time interval t = 1, and the energy of each node varies on the basis of its utilization. The sensor node only forwards its sensing data, it consumes less energy as compared to other devices that are forwarding their data along with the data of other several nodes like N8 and N4. Moreover, Figure 2b presents the energy level of each node after a specific time t = 2. According to the figure, the node N4 loses its battery frequently as compared with other devices because of the maximum load  
Figure 1: Cluster-based routing with one-hop, two-hop and multi-hop routing.  
of the network and other devices still have enough residual energy. Therefore, the main concern is to consider those nodes that have enough residual energy by reconstructing the network. The main problem is to choose the \(CH\) with the highest remaining energy for better network life and support. Thus, network is restructured in such a way that the \(CH\) must carry maximum number of neighboring nodes. The \(CH\) must carry maximum residual energy for long time support.