## 2 Related Work  
Considering the huge and scalable networks, the difficulty in WSN-assisted IoT differs differently from that of regular wireless and wired networks. The usual routing protocol, which is based upon IP and does not provide scalability, is insufficient for the WSN-assisted IoT [13]. As a result, a wide variety of efficient routing methods have been created to satisfy the demands of WSN-assisted IoT [14; 15]. The majority of routing protocols fall into one of three categories: data-centered routing, GPS-based routing, and hierarchical routing. The best routers in every cluster are promoted to the title of Cluster Head (CH) in hierarchical routing, which groups nodes into clusters. The local member transmits the data to the cluster's CH. The data are combined by CH into one packet [16]. A number of researchers have developed various clustering strategies in order to increase the lifetime of networks and data transmission efficiency. The work in [17] introduced the low energy adaptive cluster hierarchy (LEACH), with the goal of introducing the concept of a cluster-based strategy while improving energy efficiency over older systems. It is intended for use in applications where each sensor is restricted by power sources, such as batteries. LEACH divides sensor nodes into clusters, with each cluster having an assigned node known as the \"Cluster Head\" (CH). The CH is in charge of aggregating and transferring data from its cluster nodes to a central base station or sink node. LEACH's fundamental idea is to spread energy consumption equitably across the network by rotating the CH duty among the sensor nodes over time. While LEACH was created to extend the life of wireless sensor networks, it does have several limitations that become more apparent when applied to bigger and more complicated contexts, such as IoT networks. As the network is expanded across a large area, the amount of distance between CH and BS grows, resulting in huge energy loss. Second, the LEACH CH selection process is randomized and does not guarantee the most suitable node allocation for CH. Table 1 presents the comparison among various existing solutions in this domain. \begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Ref** & **Protocol** & **Description \& Benefits** & **Limitations** \\ \hline
[17] & LEACH & Considers single-hop communication, formation of cluster heads, general framework suitable to all applications, medium energy consumption & Poor network lifetime, random CH selection, non-scalable \\ \hline
[18] & LEACH-C & Considers centralized single-hop communication network, formation of cluster heads based on node energy level, uniform distribution of clusters, medium energy consumption & BS involvement, non-even load distribution \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison with Existing Solutions. Multi-hop LEACH (M-LEACH) is an expansion of the standard LEACH protocol that integrates multi-hop transmission to overcome the restrictions of traveling a long distance between Cluster Heads (CHs) and Base Stations (BSs) in wireless sensor networks (WSNs) [19]. M-LEACH attempts to increase energy economy and network performance by allowing intermediary nodes to operate as data relays. The primary idea underlying M-LEACH is to build a multi-hop link from the CHs to the BS, where data are transmitted across numerous intermediary nodes before arriving at the final destination. This helps to distribute the network's energy load more equally and allows for communication over longer distances without severely depleting the energy of CHs. To address the shortcomings of LEACH, a centralized form of LEACH (LEACH-C) was proposed. LEACH-Centralized combines the advantages of both LEACH and centralized techniques in order to deliver a more energy-efficient and controlled data collection process [18]. A centralized controller or base station is important in managing network functioning and data communication in LEACH-C.