# Hybrid Zoning Algorithm to Optimize Overhead in Smart Mobile Communication
## 6 Results  
We implemented our algorithm in Network Simulator NS-3 [33] that contains the native OLSR protocol module. A series of simulation experiments was conducted to analyze and compare the performance of four algorithms: OLSR, Z-MPR, GFR and Z-GFR. We compared our proposals with OLSR protocol to measure the improvement compared to standards in term of network performance. Comparing the Z-GFR with other techniques permits knowing the best algorithm. However, it does not permit measuring the percentage of enhancement compared to well known protocols. We used bonmmotion [34] to generate the same random behavior of nodes for all simulations for realistic comparison. The simulations consisted of different densities of nodes moving randomly in a fixed area of 1000 m \(\times\) 1000 m. This increased the number of devices in specific regions and helped us to study and compare the impact of the density on different routing protocols. Moreover, with the increase of the number of nodes, the broadcasting was also increased, affecting the performance of the network negatively, which gave us the opportunity to prove the effectiveness of Z-GFR by reducing the amount of useless broadcast messages. The simulations were run under the same conditions and network configuration. Table 1 summarizes the simulations' parameters. We started 10 udp communications at the second 50 th to measure the impact of Z-GFR on data communication between nodes. The twenty nodes exchanged udp packets of size 200 bytes at rate 256 kbps until the second 90 th. We used flow monitor tracing [35] to extract the network metrics. We compared the four algorithms in terms of the number of generated, received and transmitted TC messages; the number of packets exchanged in the network; and the number of dropped packets in the physical layer of nodes. For the udp sockets, we measured the throughput, the loss of packets, the packet delivery ratio (pdf) (e.g., the proportion of packets successfully received) and the delay. Figure 12 shows the number of generated TC messages by all the MPRs in the network. The number of MPRs remains the same for the four protocols, which allows generating approximately the same number of TC messages as the original OLSR. However, Z-MPR, GFR and Z-GFR affect the retransmission and the reception of TC messages since they affect the structure of MPRs or reduce the number of transmissions. Figure 13 shows the number of retransmissions of TC messages by all the MPRs. We remark that the number of transmissions of TC messages in Z-MPR differs slightly from that of the original OLSR. This is explained by the fact that Z-MPR modifies the MPR layout, which changes the density of each MPR and allows rebroadcasting TC messages freely without interferences. The GFR and Z-GFR decrease, as expected, the number of retransmissions by deleting the useless ones. The gain in terms of number of retransmissions is increases as the network becomes denser. The two protocols minimize approximately 28% of retransmissions. However, we remark that the two protocols have a small difference of number of retransmissions due to the MPR distribution near the border line of the two zones, which affects the search for the alternative path \(P\). These reductions of retransmissions help to free the channel for data transmission between nodes. \begin{table}
\begin{tabular}{c c} \hline \hline
**Simulation Environment** & **Parameters** \\ \hline Area size & 1000 m \(\times\) 1000 m \\ Number of nodes & 80, 100, 120, 140, 160 \\ Radio range & R = 100 m \\ Modulation & 802.11b peer to peer mode \\ DataMode & DsssRate1 Mbps \\ ControlMode & DsssRate1 Mbps \\ Mobility model & Random Mobility \\ Simulation time & 100 s \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Simulations’ parameters. Figure 12: Number of generated TC messages. Figure 13: Number of retransmissions of TC messages. The influence of the three modified protocols on the number of retransmissions impacts the reception of TC messages.