# Network Lifetime Improvement through Energy-Efficient Hybrid Routing Protocol for IoT Applications
## 4 Proposed Hybrid PSOGA
### Proposed Hybrid-Based PSOGA Routing
The applicability of our strategy is immense, for example, vast horticultural fields where environmental parameters, such as atmospheric temperature and humidity, soil mois

Figure 3: Grid formation in a WSN. ture, soil temperature, and soil pH, are to be measured [42]. In addition, it can be applied to any event detection application, such as wildfire detection [43] and seismic monitoring [44]. Apart from these, it can also be used in structural health monitoring where parameters such as humidity, temperature, stress, and strain are required to be measured [45]. In several of these above scenarios, it is cost effective to use non-rechargeable nodes. In real-life deployments, the geographical area may not be rectangular. Our thinking is that a rectangle can be fitted to any irregular geographical area by using its extents, much like how irregular features in images are processed in a bounded rectangle. This is likely to have the effect of having some grids on the periphery of the geographic region where there may be very few nodes, or even none. An empty grid will not require a cluster head and will, thus, not participate in the path selection process. It is assumed that a large number of radio channels are available for transmission, which will mitigate interference issues [46]. In Section 6, the evaluation of the PSOGA is presented with various performance metrics, including the total residual energy, the network throughput, the total number of alive nodes at the end of each iteration, and the packet delivery ratio (PDR). The PSOGA was compared with the conventional LEACH protocol, with the parametric setting given in Table 2.

## 6 Results and Discussion

The proposed strategy was further tested in five different scenarios with varying network area sizes, number of grids/clusters, and total number of nodes, as shown in Table 3, in which the number of grids varies with different cases and ranges between 8 and 100, with the node population ranging from 100 to 1250 based on the size of the network area. The details of these scenarios are given in Table 3.

The entire setup was in an area with the base station located at the center, as shown in Figure 3.

The proposed PSOGA method was compared with the conventional LEACH protocol. The parametric settings are given in Table 2 and the grid formation is shown in Figure 3. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Values** \\ \hline Network area & 100 m \(\times\) 100 m, 200 m \(\times\) 200 m and 500 m \(\times\) 500 m \\ \hline Total number of nodes & 100, 200, 625 and 1250 \\ \hline Initial energy & 0.2 ] \\ \hline Power amplification (\(\varepsilon_{fs}\)) & 10 pj/bit/m2 \\ \hline Power amplification (\(\varepsilon_{mp}\)) & 0.0013 pj/bit/m4 \\ \hline Transmitter/receiver energy (\(E_{dec}\)) & 50 nJ/bit \\ \hline Base station location & (50, 50), (125, 125) and (250, 250) \\ \hline Number of rounds & 2500 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Network parameter setup. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Case Study** & **Network Area** & **Number of Grids** & **Total Number of Nodes** \\ \hline
2 & 100 m \(\times\) 100 m & 4 \(\times\) 4 & 100 \\ \hline
3 & 200 m \(\times\) 200 m & 4 \(\times\) 4 & 200 \\ \hline
4 & 500 m \(\times\) 500 m & 10 \(\times\) 10 & 625 \\ \hline
5 & 500 m \(\times\) 500 m & 10 \(\times\) 10 & 1250 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Different network setups for simulation. The performance evaluation was done based on the total number of packets reaching the BS, the total number of alive nodes, the residual energy of the network, the packet delivery ratio (PDR), and the throughput of the network. The packet delivery ratio (PDR) indicates the ratio between the number of packets that the sink or destination receives and the entire number of packets sent by the source. Sections 6.1-6.7 demonstrate the performance evaluation based on different grid configurations and network settings.