## 3 Proposed Protocol  
This section presents the design and development of the proposed Decision-based Routing for Unmanned Aerial Vehicles and the Internet of Things (DR-UAVIoT) routing solution based on decision criteria. The proposed solution is divided into two main phases including data routing among UAVs' nodes and data routing from UAVs to IoT infrastructure devices. This solution is used for data routing decisions and only used to gather the data from IoT networks especially when the ground network is congested and not able to forward the data toward the decision center or to the main servers. The IoT infrastructure is used to collect the data and forward it to the UAVs' nodes and then, from the UAVs' nodes, the data is forwarded to the cloud or backbone devices for better decision-making. Different steps are involved to design the two main modules of the proposed solution. For the first module (UAV-to-UAV data communication), the protocol provides data routing facilities among UAV nodes to UAV nodes. Whereas, in the second module, the proposed solution is utilized for data gathering from BS and further linked with the IoT network at the ground. Normally the BS has enough resources in the form of bandwidth, transmission power, and coverage. The first module is used for data communication by using node locations services as used in [22]. The main purpose of location services is to obtain updated and real node locations. The proposed DR-UAVIoT uses location service to serve the IoT network services. The UAVs' nodes are available in the network to assist the IoT networks in the presence of dense and sparse network conditions. The proposed solution detects the network density on the ground after some time. Based on a distance calculation, the UAV nodes check the number of UAV nodes in the network and call for congested traffic zones by sending one short message. The UAVs also check the battery power level to participate in data collection in the network and give priority to those drones which have enough battery power. Figure 2 shows the drone components. The role of the control station of BS is very significant in IoT and UAV traffic. The BS, or control station, is used for supporting the network and providing high-power transmission and receiving features. The fast and perfect data communication of UAVs and IoT nodes is a challenging task because the pure ad hoc networks have limited communication services where the BS provides the support to boost these networks and adjust the UAVs' nodes' channel conditions and path. Data collection is a challenging task especially when the BS has not fulfilled the network requirement. Each BS uses a certain frequency to minimize the interference whereas the communication range of BS is determined by the size of the cell. The BS is connected with the central entity called the mobile telecommunication switching office for further data analysis. _Module 1 (UAV-to-IoT and UAV-to-UAV Data Communication)_  
In this module, the proposed routing solution is used for data delivery. This module is further divided into main phases including UAV-to-IoT network and UAV-to-UAV data routing. The first phase of UAV-to-IoT is gathering information from ground IoT networks where the location of the node is known by using a Global Positioning System (GPS) [23]. The UAV has a routing strategy to identify the targeted location such as a stadium, ground, or any disaster area by using real-time information on nodes density on the ground IoT network. In the first step, the proposed DR-UAVIoT protocol collects the nodes' density information from the centralized IoT infrastructure. In the second step, the UAVs' nodes detect the connectivity factor and select the exact required area for data gathering. For the node density, the proposed solution specifies the area which is already segmented into fixed zones and uses a communication range of up to 250 m. UAVs' nodes cover each area zone and update the information by using Hello packets with IoT nodes at the ground.