# Cluster-Based Routing Protocol with Static Hub (CRPSH) for WSN-Assisted IoT Networks
## 1 Introduction  
In a multihop scenario, the sensor device transfers the data to the IoT hub via intermediary sensor devices. WSN-assisted IoT networks are energy constraint networks. So, energy-efficient routing methods are necessary for WSN-assisted IoT networks operating in an energy-constrained environment. However, in WSN-assisted IoT networks, energy depletion and hardware faults might result in device failures. Additionally, this might affect data transmission. A reliable route significantly reduces data retransmissions, which can help in congestion reduction and energy conservation. Generally, the sensor devices are typically deployed densely throughout the WSN-assisted IoT networks. A high number of sensor devices covering a monitoring area might result in duplicate data. The clustering method can be used to overcome this problem. The Cluster Heads (CH) collect data from Cluster Members (CM) prior to sending them to the hub. The clustering technique reduces network traffic, whereas the path reliability is ensured by the multipath technique. These two approaches encourage the development of a hybrid technique that incorporates the benefits of both strategies [1, 2].  
Devices in WSN-assisted IoT networks must hunt for a way up to the IoT hub for data transmission [3]. Although the device's technical capabilities are improving all the time, the device's battery capacity is not keeping up [4]. IoT gadgets use nonrechargeable limited-power batteries. It is also challenging to replace their battery while the devices are in use. Moreover, we need advanced power-saving schemes to make these IoT technologies more adaptable. Due to the energy constraints and limited memory capacity of these IoT devices, we require more energy-efficient routing protocols to route data to the IoT hub [5; 6].  
A WSN-assisted IoT network is a unit of Low-power and Lossy Networks (LLNs) which are categorized as minimal power and energy-constrained devices that are interrelated with links, where LLN devices can act as data originator and router [7]. In LNNs, power conservancy and network lifetime improvement are the foremost challenges [8]. The routing over LLNs' WG of the Internet Engineering Task Force (IETF) produced specifications for both the RPL protocol (RFC 6550) and a set of related extensions for various routing metrics, objective functions, and multicasts. The wireless links in LNN are lossy because of the quality of radios and minuscule size of LNN, and the routing protocols in LLN provide routing within the network. The state-of-the-art routing protocols for WSN-assisted IoT networks can be classified into three types as flat, hierarchical, and location-based protocols [9].  
All sensor devices in _flat-type routing_ protocols perform an equal role in acquiring information from the environment and relaying it to the IoT hub. The distance between the devices is computed based on the received signal strength in _location-based routing_ protocols. This information is used for efficient data transfer. _Hierarchical routing protocols_ are the most widely used routing protocols for WSN-assisted IoT networks. They partition the whole network area into different regions. Each partition has a master node and many member nodes. The master node is responsible for gathering data from the member nodes and transmitting it to the hub. Additionally, it is capable of effectively balancing the load on the sensor devices by assigning distinct tasks to distinct devices. Hierarchical routing is a viable option for lowering energy consumption by eliminating redundant data transmission. Due to its high energy efficiency, it outperforms other types of routing protocols [10; 11; 12; 13; 14].  
Section 2 presents an extensive literature survey and Section 3 describes the system model. Section 4 focuses on the protocol's description as well as the algorithms that are used to develop it. Section 5 presents the findings of the simulation and Section 6 provides a conclusion and future research direction.