## 5 Simulation Experiments
### Analysis
#### 5.3.2 Analysis of Experiment Results  
To test the advantages of the improved LEACH routing protocol algorithm based on the differential evolution algorithm (the DE_LEACH routing algorithm), this paper compares it with the traditional MTE protocol, the classical cluster-based routing algorithm LEACH protocol, the LEACH_C protocol in terms of network survival time and network quality. The network survival time is defined as the time needed from the start of the simulation to the end of last node consuming its energy. The network quality is defined as the differential rate of change of the total data amount sink nodes receive as time changes. Figure 4 is a comparison chart of WSN lifetime. The abscissa is time, and the ordinate is the number of live nodes in the network. The DE_LEACH refers to the improved protocol. Figure 4 reflects the comparison of network survival time between the improved protocol and the traditional one. It can be seen that the improved the DE_LEACH routing algorithm proposed in this paper survives longer than the MTE protocol, the traditional LEACH, and the LEACH-C protocol algorithm. Nodes die in less than 100 s because the energy consumption of nodes is not in balance in the MTE protocol. Nodes closer to sink nodes are always responsible for data relays, consume their energy very fast, and it affects the life cycle of the entire WSN. Comparatively speaking, the performance of the MTE protocol is the worst. The LEACH-C is also an improved LEACH protocol, and centrally distributes location, number and cluster size of cluster heads via sink nodes for more reasonable cluster partition. The LEACH-C protocol extends a life cycle longer than the LEACH protocol. Figure 5: Comparison of WSN lifetime. The LEACH protocol begins to fade in about 410 s. The DE_LEACH routing algorithm in this paper fades in about 520 s, and the time when the first node dies is 25% later. In addition, no node survives in the LEACH protocol in about 570 s, and that time in the DE_LEACH algorithm is about 740 s. After a period of its operation, the remaining energy of nodes in the network are not in balance in the traditional LEACH, and the DE_LEACH routing algorithm proposed in this paper can balance energy loss among nodes inside clusters to prevent premature blind nodes, thereby extending the survival time of the network. The larger the network scale, the more obvious the energy saving effect. Figure 5 is a comparison chart of WSN quality. The abscissa is time, and the ordinate is the total data amount sink nodes receive. The chart reflects the network quality comparison between the improved DE_LEACH routing protocol and the traditional one. In Figure 5, the network quality of the improved DE_LEACH routing algorithm is better than that of the MTE and the traditional LEACH protocol, and second only to the LEACH-C protocol. The MTE protocol has been at a comparatively lower level in terms of data amount, and the total data amount sink nodes receive is only about 11% of that the traditional LEACH protocol receives. In the traditional LEACH protocol, the total data amount sink nodes increases steadily before 400 s, and at about 580 s, the amount does not increase any more, meaning that the network life ends now. For the LEACH-C protocol, the cluster structure is more reasonable due to cluster heads allocated by sink nodes based on energy and location information, and the data amount is comparatively larger in the protocol, that is to say, a large data redundancy. But in about 650 s, the total data amount does not increase any more. In the proposed DE_LEACH protocol, the cluster distribution is more even, the number of cluster heads is more reasonable, and the data amount increases steady before 580 s until in about 700 s. Compared to the traditional LEACH protocol, the total data amount sink nodes receive increases around 35%. The larger the data amount the sink nodes receive, the greater the redundancy, the more accurate the judgment on the environmental monitoring. Figure 6: Comparisons of WSN Quality.