# Network Lifetime Improvement through Energy-Efficient Hybrid Routing Protocol for IoT Applications
## 4 Proposed Hybrid PSOGA
### Proposed Hybrid-Based PSOGA Routing
For each scenario, the simulation was performed ten times and the mean was plotted for each metric. ### Case Study 1

Figure 4 shows the results of Case Study 1: 2 \(\times\) 4 grids, 100 nodes. The network structure (Figure 4a) shows eight grids with the selected cluster heads marked in numbers in triangular shapes and connected by black lines. The comparative results of the performance metrics are shown in Figure 4b-f. For each metric, the network was generated and the simulation was performed 10 times. The average of the 10 simulations, each over 2500 rounds, were plotted, along with the standard deviation. The number of packets reaching the BS is shown in Figure 4b. After 2500 rounds, the packets sent to the BS with the PSOGA improved by 278.94% and 5.55% as compared to LEACH and PSO, respectively. Figure 4c shows the number of nodes alive at each round. The points at which all the nodes were dead for LEACH, PSO, and the proposed PSOGA were after 700, 1900, and 2000 rounds, respectively, which shows significant improvements of 185.7% and 5.26% over LEACH and PSO, respectively. The residual energy also demonstrated promising improvement, as shown in Figure 4d. The energy was depleted after 500, 1700, and 1800 rounds for LEACH, PSO, and the proposed PSOGA, respectively. Thus, the network energy in the proposed PSOGA achieved an enhancement of 259.06% compared to LEACH and 9.97% compared to PSO. Figure 4e demonstrates improvements in the PDR by 298.75% and 67.5% compared to LEACH and PSO, respectively. Furthermore, the throughput with the PSOGA was increased by 7.13% and 49.5% as compared to PSO and LEACH, respectively, as shown in Figure 4f. Figure 4g is a representative graph showing the nodes alive for each of the 10 simulations for LEACH, PSO, and PSOGA. The average of the 10 simulations is shown in Figure 4c. As mentioned earlier, 10 simulations were similarly performed for each of the other metrics. The bar graph in Figure 4h shows the simulation times for LEACH, PSO, and PSOGA. Figure 4i shows the difference between PSO and PSOGA, from 1350 to 1650 rounds. ### Case Study 2

Figure 5 shows the results of Case Study 2: 4 \(\times\) 4 grids, 100 nodes. The network structure (Figure 5a) shows 16 grids, with the selected cluster heads marked in numbers and connected by a black line. The results of the performance metrics show that with 100 nodes, the packets sent to the BS (Figure 5b) improved by 268.42% and 9.36% when compared to LEACH and PSO, respectively. Further, the PSOGA demonstrated an increase in the number of alive nodes by 155.43% and 10% as compared to the PSO and LEACH, respectively. The results in Figure 5d illustrate that the number of alive nodes became zero after 500, 1850, and 1994 rounds for LEACH, PSO, and the proposed PSOGA algorithm, respectively, leading to significant gains of 274.64% and 10.4% vis-a-vis LEACH and PSO, respectively. Similarly, the PDR was improved by 314.25% and 72.48% in comparison to LEACH and PSO, respectively (Figure 5e). Finally, the proposed PSOGA demonstrated throughput enhancement of 37.5% and 4.84% compared to LEACH and PSO, respectively, as shown in Figure 5f. Figure 4: _Cont._

As compared to Case study 1: \(2\times 4\) grids, 100 nodes, it is evident that although the number of nodes in both the case studies was the same, the difference lies in the grid structure. In the case of the 4 \(\times\) 4 grid, the network performed better in terms of the evaluated parameters. For instance, the number of packets sent to the BS in Case Study 2 was 3.5 \(\times\) 10\({}^{6}\), almost 3 \(\times\) 10\({}^{5}\) higher than in Case Study 1, which had 3.2 \(\times\) 10\({}^{6}\) packets. Similarly, the network structure demonstrated a slight improvement in the throughput, with a value of almost 17,500 as compared to 16,000 in the 8-grid structure. Figure 4: Results of Case Study 1: \(2\times 4\), 100 nodes. (**a**) Network structure for Case Study 1. (**b**) Packets reaching the BS. (**c**) Total alive nodes. (**d**) Total residual energy. (**e**) PDR. (**f**) Throughput.