# Robust Clustering Routing Method for Wireless Sensor Networks Considering the Locust Search Scheme
## 5 Experiments and Simulation
### Methods of Comparison and Parameter Settings  
To prove the efficiency of the proposed method, it has been compared against one of the most popular clustering routing protocols: the Low Energy Adaptive Clustering Hierarchy Protocol (LEACH). Furthermore, the proposed technique has also been compared against other recent metaheuristic schemes used in clustering routing protocols, namely the Gray Wolf Optimization (GWO) algorithm.  
The simulation requires the parameter settings listed in Table 2. To ensure a fair comparison, these parameters have been configured with the same values for all the routing protocols considered in the experiments. The simulation parameters include the size of the sensing area, the number of sensor nodes in the network, the size of the packets, the initial energy of the nodes, and other values necessary to simulate the behavior of the network during the transmission-reception process.  
Additionally to the simulation's parameter settings, the proposed method and the protocols in comparison need particular parameter configurations to ensure their best performance. These parameters are reported in Table 3.  
\begin{table}
\begin{tabular}{l c} \hline \hline
**Parameter** & **Value** \\ \hline Sensing area & 100 m\({}^{2}\) \\ Packet size \(l\) & 4000 bits \\ Number of sensor nodes \(N\) & 100 \\ The energy dissipation for transmitting or receiving \(1\) bit & 50 nJ/bit \\ of data \(E_{dec}\) & 5 nJ/bit \\ Energy for \(1\) bit of data aggregation \(E_{DA}\) & 5 nJ/bit \\ The coefficient of energy dissipation in the multipath & \\ attenuation model \(\varepsilon_{mp}\) (transmission coefficient & 0.0013 pJ/bit/m\({}^{4}\) \\ amplifier) & \\ The coefficient of energy dissipation in the free space \(\varepsilon_{fs}\) & 10 pJ/bit/m\({}^{2}\) \\ (transmission coefficient amplifier) & 0.003 J \\ Initial energy of sensor nodes \(E_{o}\) & 0.003 J \\ The coefficient of energy dissipation in the multipath & \\ attenuation model \(\varepsilon_{mp}\) (transmission coefficient & 0.0013 pJ/bit/m\({}^{4}\) \\ amplifier) & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Parameter settings.  
The LEACH protocol only requires the percentage of cluster heads assigned in every round, whose value usually is at least 5% of the alive nodes. Therefore, we have configured this value to 0.05. The YSGA method needs the number of search agent groups as an initial parameter. According to the author's recommendation, this value has been set to 4 since extensive experiments have demonstrated that it reaches its best performances when four groups are configured for the search process. On the other hand, the GWO employs one parameter to regulate the exploration-exploitation in the search process. According to the author's recommendation, this parameter variates linearly from 2 to 0 throughout the optimization stage. Finally, the LS-II method only requires the number of best individuals needed for the social phase. This value has been set to 10 since the method's best performance is achieved using this value. As additional parameters, the YSGA, GWO, and LS-II algorithm require the population size and the maximum number of iterations, which have been set to 20 and 50, respectively.  
All the experiments have been carried out using the MATLAB R2019a software on a PC with the Intel(r) Core TM i7-8550u processor at 1.80 GHz.