## 5 Experimental Results and Analysis
### Simulation Results of CFSFDP-E Compared with LEACH and CFSFDP  
To test the performance of CFSFDP-E, we compare it with LEACH and CFSFDP. Results are shown in Table 5. FND means the first node dies, and HND, LND represent the half of nodes die and last node dies. The network lifetime is defined as the round that all nodes' energy is exhausted. If the protocol can balance energy well and last dead time is late, it can be defined that the network lifetime is long. In this paper, we assume that the death of 90% nodes means all nodes dead.  
We also compare the CFSFDP algorithm in the WSN. It divides nodes into clusters only based on local density \(\rho\) and distance \(\delta\) and the \(\gamma\) value for each node is calculated through Equation (5), while in the proposed CFSFDP-E algorithm, the formation of clusters considers not only these two factors, but also the residual energy of each living node. These algorithms are simulated in the same experimental scenario. The threshold \(\eta\) should be a dynamic value rather than a fixed number to determine the number of CHs. Before discussing about threshold, we choose 10% of living nodes as the number of CHs in each round for both CFSFDP and CFSFDP-E.  
From Table 5, we can find that the FND of CFSFDP algorithm in WSN occurs much earlier than that of LEACH. The reason for this result is that the CFSFDP algorithm selects cluster heads with local density and distance, so the location of all nodes is fixed if there is no node to die and the value of local density and distance will not change, which means when a node is selected as CH, it will remain  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter** & **Value** & **Parameter** & **Value** \\ \hline Area & 100 m \(\times\) 100 m & \(E_{TX}\) & 50 nl/bit \\ Sink Node & (50,150) & \(E_{RX}\) & 50 nl/bit \\ Initial Energy & 0.5J & \(\varepsilon_{fs}\) & 10 pJ/bit \\ Packet Length & 4000 bits & \(\varepsilon_{mp}\) & 0.0013 pJ/bit \\ Control Length & 100 bits & \(E_{DA}\) & 5 nl/bit \\ \(p\) & 0.1 & \(r_{\text{max}}\) & 3000 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Experimental Parameters.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**ALGORITHM** & **FND** & **HND** & **LND (90\%)** \\ \hline LEACH & 688 & 874 & 1075 \\ CFSFDP & 91 & 972 & 1765 \\ CFSFDP-E & 822 & 1009 & 1036 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Network lifetime comparison of LEACH, CFSFDP and CFSFDP-E.  
the CH in the following rounds until the energy is exhausted. Thus, the round of FND is 91, which is much earlier than 688 in LEACH. However, the LND in CFSFDP happens later compared with LEACH and CFSFDP-E. It is obvious that the energy consumption of the CFSFDP algorithm is unbalanced.  
The proposed CFSFDP-E algorithm takes energy into account. When selecting CHs, we choose the nodes with high local density, large distance and high residual energy. The result shows that CFSFDP-E clustering algorithm can effectively postpone the FND. The FND of CFSFDP-E is 822, which is about nine times the 91 of CFDFDP. It is also longer than that of LEACH which means CFSFDP-E can balance the energy consumption of the networks effectively. Figure 3 shows the simulation results of these three algorithms. Figure 4 is the energy consumption of every round in LEACH and CFSFDP-E. Obviously, CFSFDP-E can keep most of the nodes alive in the network, which means it can balance the energy consumption more effectively than LEACH, so that the existence of the death of first node happens later.