# Fuzzy Logic-Based Geographic Routing Protocol for Dynamic Wireless Sensor Networks
## 4 Simulation and Complexity Analysis
### Comparison of Network Performance
#### 4.2.1 Packet Delivery Ratio  
The packet delivery ratio of the network refers to the ratio of the number of data packets received by the destination node to that sent by the source node, which reflects the reliability of the routing protocol.  
Figure 9 shows the impact of node number on the packet delivery ratio in a quickly changing network (\(v_{\mathrm{max}}=40\)).  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Values** \\ \hline Network simulation & 10 min. \\ Network node number & 20, 60, 100, 140, 180, 220 \\ Application & CBR for UDP \\ Maximum speed & 10, 15, 20, 25, 30, 35, 40 m/s \\ Packet size & 1280 bytes \\ Propagation delay & 1 \(\upmu\)s \\ Channel bit rate & 1 Mbps \\ Frequency of Hello message & 1 Hz, 1.5 Hz, 2 Hz, 2.5 Hz, 3 Hz, 3.5 Hz and 4 Hz \\ Maximum Num\_pre & 10 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Network parameters in simulation.  
As shown in Figure 9, with increases in node number, the packet delivery ratios of the four protocols also gradually increase and approach a stable value. When the network is relatively dense (\(n\geq 100\)), the packet delivery ratios of the four protocols above show little difference, owing to the low probability of the routing void. However, the FLGR protocol performs better in the sparse network (\(n\leq 60\)). This improvement is due to more void nodes occurring in the sparse network, and the FLGR protocol can thus effectively discard the void node through the routing void avoidance scheme. Although the routing void problem can be solved in the other three protocols, the transmission delay vastly increases because of the location server algorithm. As a result, the packet loss ratios of the GPSR, GPSR-AD, and LPESG protocols are higher than that of the FLGR protocol.  
Figure 10 shows the impact of maximum speed on the packet delivery ratio in a sparse network (\(n=60\)).  
Figure 10: Impact of maximum speed on packet delivery ratio with \(n=60\).  
Figure 9: Impact of node number on packet delivery ratio with \(v_{\max}=40\).  
As shown in Figure 10, the packet delivery ratios of the four protocols decrease with the increase in maximum speed. In addition, the FLGR and LPESG protocols perform better than the GPSR and GPSR-AD protocols in a slowly changing network (\(v_{\max}\leq 30\)). The packet delivery ratio of the FLGR protocol is higher than that of the others in a quickly changing network (\(v_{\max}\geq 40\)). This phenomenon occurs due to the following reasons: (1) Instability of the link increases with the increase in maximum speed, resulting in a decline of the packet delivery ratio. (2) In a slowly changing network (\(v_{\max}\leq 30\)), the routing void problem can be avoided by discarding the void node in the FLGR protocol, and it can be solved by adjusting the transmission power in the LPESG protocol. For the GPSR and GPSR-AD protocols, the peripheral forwarding mode is adopted when meeting the routing void problem, which can bring about the network planarization problem. (3) In a quickly changing network (\(v_{\max}\geq 40\)), the location information of destination node should be frequently obtained in the GPSR, GPSR-AD, and LPESG protocols, which effectively increases the transmission delay.