# Adapting Probabilistic Flooding in Energy Harvesting Wireless Sensor Networks
## 6 Performance Evaluation
### Simulation Scenarios Evaluation  
The main objective of this section is to compare the coverage efficiency of PF against RPF in energy harvesting environments. The simulations performed consider various GRG groups with connectivity radius 0.10, 0.20 and 0.30. For each group, ten different topologies are created and the depicted results are the average values obtained by the simulations on these topologies. For each case, the forwarding probability is set to a value such that full coverage is ensured with high probability under non-energy harvesting environments (i.e., \(q\geq\hat{q}\)). Network nodes are operating under the simplified proposed Markov model (i.e., Figure 3) when the energy harvesting environment is activated. Columns 2 and 3 of Table 2 present the average number of links (\(\ell\)) and the average number of neighbors (#Neighbors) for the three different GRG groups with connectivity radius 0.10, 0.20 and 0.30, respectively. Columns 4 and 5 present the average value of the termination time (\(\mathcal{T}\)) and the average number of sent messages under PF (\(\mathcal{M}\)) using a forwarding probability of \(q=\hat{q}\) (i.e., Column 6) and considering non-energy harvesting environments. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \(r_{c}\) & \(\ell\) & \#Neighbors & \(\mathcal{T}\) & \(\mathcal{M}\) & \(\hat{q}\) \\ \hline
0.10 & \(14,549.2\) & 29.1 & 21.6 & 3177.3 & 0.12 \\ \hline
0.20 & \(53,149.3\) & 106.3 & 14.0 & 2964.3 & 0.03 \\ \hline
0.30 & \(107,499.7\) & 215.0 & 10.0 & 4139.2 & 0.02 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Average values for \(\ell\), #Neighbors, \(\mathcal{T}\), \(\mathcal{M}\) and \(q_{0}(r_{c})\) for Probabilistic Flooding. Figure 4: \(p_{1}\) as a function of \(\alpha\), for \(\beta=0.1\) and various values of \(\gamma\). Figure 5 depicts PF coverage at termination time (i.e., \(C(\mathcal{T})\)) as a function of \(\gamma\) under energy harvesting environment, for \(r_{c}=0.10\), \(\alpha=0.1\), \(q=\hat{q}\) and various values of \(\beta\). Moreover, Figure 6 depicts PF coverage at termination time (i.e., \(C(\mathcal{T})\) as a function of \(\gamma\) under energy harvesting environment, for \(r_{c}=0.10\), \(\beta=0.1\), \(q=\hat{q}\) and various values of \(\alpha\). It is observed in both figures that full coverage under PF is obtained only for a small range of values for \(\alpha\), \(\beta\) and \(\gamma\), while, for the rest, the coverage is reduced. It is shown that the proposed Markov chain highlights the incapability of PF for full coverage under an energy harvesting environment. The fact that PF fails to obtain full coverage is clearly shown in Figure 7 which depicts PF coverage at termination time as a function of the connectivity radius for various sets of \(\alpha\), \(\beta\) and \(\gamma\). Note that in all cases the forwarding probability is set to a value such that full coverage is ensured with high probability under non-energy harvesting environments. Figure 5: Coverage at termination time \(C(\mathcal{T})\) under PF for \(\alpha=0.1\) and various values of \(\beta\) as a function of \(\gamma\) for \(r_{c}=0.10\). Figure 6: Coverage at termination time (\(C(\mathcal{T})\)) under PF as a function of \(\gamma\) for \(\beta=0.1\), \(r_{c}=0.10\) and various values of \(\alpha\). Figure 8 depicts coverage as a function of time for \(\alpha=0.3\), \(\beta=0.2,\gamma=0.6\), under both PF and the proposed RPF and for all considered topology groups (i.e., \(r_{c}=0.10\), \(0.20,0.30\)). It is observed that the proposed mechanism obtains full coverage in all cases, while the coverage under PF is significantly reduced. It is also observed that both mechanisms expound the same increment rate regarding coverage for the first time steps. However, for the larger values of time, PF coverage is significantly reduced and only RPF succeeds at obtaining full coverage.