## 3 The Clustering Protocol
### Node Dormancy Mechanism
The commonality of the three protocols is that they do not consider the location of the node, resulting in some nodes with much energy and relatively remote locations being elected as the CHs, thus causing unnecessary energy waste. Therefore, the protocol in this paper considers the energy and position of the node, so that the CH in one round tends to have more energy and better position, thus effectively extending the death round of the first node. ### Comparison of the Network Lifetime

SEP considers the impact of the initial energy on the basis of LEACH. Yet in the homogeneous networks, the initial energy of all of the nodes is the same, then SEP equals LEACH. As shown in Figures 14 and 15, the numbers of surviving nodes with the rounds of SEP and LEACH are very close, which is a good testimony to its efficacy. With the continuous rounds of iterations, the advantage of DEEC gradually emerged. Compared to LEACH, DEEC extends the network lifetime by 8.93% and 12.37% in the two homogeneous networks, respectively. Compared to DEEC, the protocol in this paper further extends the network lifetime by 25.89% and 24.36%, respectively. As shown in Figure 16, in heterogeneous networks, compared to LEACH, the number of surviving nodes in SEP is less than that in LEACH in the early period. SEP causes many nodes with high initial energy to die in the early period, so it has more nodes with less initial energy in the network. During the later period, the energy distribution of the nodes in SEP is more balanced so that it can maintain a longer network lifetime. Considering the initial energy and residual energy of the node, DEEC has advantages in heterogeneous networks compared to SEP and LEACH. Compared to LEACH, SEP, and DEEC, the protocol in this paper leads to the survival of 86 nodes in the 1400 th round, thus ensuring that the protocol can carry more rounds of network communication, while LEACH, SEP, and DEEC retain only 28, 32, and 33 nodes, respectively. Figure 13: The round of the first node’s death. LEACH: Low-Energy Adaptive Cluster Hierarchical; SEP: Stable Election Protocol; DEEC: Distributed Energy-Efficient Clustering. Figure 16: The number of surviving nodes varies with the round (the initial energy is evenly distributed at 0.4–0.8 J). Figure 14: The number of surviving nodes varies with the round (initial energy = 0.4 J). Figure 15: The number of surviving nodes varies with the round (initial energy = 0.8 J). ### Comparison of the Network Energy Consumption

In this paper, the energy consumption model proposed in [12] is referenced in determining the optimal cluster number of the network, and a new optimal cluster number method is proposed according to the specific network model. Then, for each round of data transmission, we determine the most suitable CH based on the remaining energy and positions of the nodes in the cluster. As shown in Figure 17, Figure 18, Figure 19, compared to the other three protocols, the number of clusters calculated by the protocol in this paper is superior, and the CHs selection mechanism is more reasonable, so less energy is consumed in the network. Figure 17: The residual energy varies with the round (initial energy = 0.4 J). Figure 18: The residual energy varies with the round (initial energy = 0.8 J). ### Comparison of the Network Throughput

Network throughput is an important indicator that fundamentally reflects the performance of a protocol. It refers to the number of packets in the network that are ultimately sent to the BS. The cluster member nodes transmit the information sensed by itself to the CH in the form of packets, and the CH fuses this information with that sensed by itself, and finally sends the information to the BS in the form of packets. During this period, if the energy of the CH is insufficient to receive, fuse, or transmit the information, all of the information of the cluster in this round cannot be transmitted to the BS, resulting in a decrease in network throughput.