# Cluster-Based Routing Protocol with Static Hub (CRPSH) for WSN-Assisted IoT Networks
## 2 Literature Review  
Various routing methods for WSN-aided IoT Networks have been suggested in recent years [15; 16; 17; 18; 19; 20]. In this part, we look at a few of the many types of new protocols. The LBDD routing protocol defines a large vertical strip of devices centered horizontally on the deployment area [21]. It is separated into g-sized sets once more. In-line devices are those that are connected to this virtual infrastructure. The data from the device is sent down the line and stored by the first in-line device that comes across it. When an IoT device detects any data, it sends it to the closest in-line device. When a hub requests data, it sends a vertical request to the virtual route [22]. First, the aligned device delivers it in both directions along the line's course. When a query is sent to the relevant data-containing sensor devices, the devices submit the data immediately to the IoT hub. The amount of queries issued might sometimes outnumber the data. Broadcasts are used by LBDD to transmit data requests over the network [23]. The line structure may be quickly and cheaply created. This line must be sufficiently wide to prevent hotspots. It lowers energy usage while increasing overhead. The AN Position Information Request packet (ANPIREQ) is sent from the source device to the ring. When the ring devices receive the request, they transmit the AN Location Information Response (ANPIRES) packet to the source, which provides the current AN's position information. The source can transmit data to the AN after receiving the response packet from the ring node. By including a small number of nodes in the ring, the Ring Routing protocol minimizes control packets. The anchor device's location is requested by the source device [24]. The anchor device location information packet is sent by the ring devices in response. The data is transmitted to the anchor device once the source device has the anchor device's position information. By aggregating the smallest number of sensor devices into the closed loop, the impacts of control packets are decreased. The RRP1 protocol is designed to operate with small, inefficient broadcasts [25]. The Railroad protocol takes advantage of the rail infrastructure to store all of the metadata associated with event data. In railroad routing, there are four main procedures. Rail construction, event notification, query request, and data transmission are among these processes [26]. When the gadget detects data, it sends the metadata associated with it to the closest station (group of rail devices). Platform devices are the equipment in the station. The process of rail building occurs just once during the set-up phase. To see if a device is on the rail, it has to know how far away it is from the nearest border device and network center. The rail is notified of the event summary via event notification messages. When the rail device receives the message, it creates a new station and sends the message to the station's platform devices. The railroad differs from LBDD in that it introduces a significant feature: the hub's inquiries are unicast rather than broadcast. The stations should be wide enough to accommodate the rail width. Finally, because the inquiry must travel a greater distance, the railroad protocol delays data transmission more than the LBDD protocol. To obtain the information, the hub sends out a query. In three stages, this question is transmitted to the source. Query forwarding on the rail, query circulation around the rail, and query notification to the source are all included. The inquiry is sent from the hub to its neighboring device and subsequently to devices along the way to the train. The inquiry circulates with the help of direction information after it enters the train. In the middle of its journey, it also inspects all of the stations. If any station has relevant data that the hub requires, the platform device sends a query notification message to the source. After receiving the query notification message, the source sends the data to the hub.