## 6 Performance Evaluation
### Routing Performance Analysis  
In this subsection, we compare our performance evaluation results (average) with DHCT [15], MCRA [18], and EDGE [16] protocols. We consider in this comparison four important performance metrics: throughput, end-to-end delay, packet delivery ratio, and power consumption:  
End-to-end delay is one of the important QoS parameter that we consider in designing our proposed routing protocol to handle the real-time traffic and deliver the packets within their playout deadlines. End-to-end delay is the time difference from the time a source node sends its data packet to the time the sink receives it, and it can be measured as sum of (transmission delay, propagation delay, queuing delay, and processing delay at each hop). We obtain an average end-to-end delay of 75 ms which satisfies the end-to-end delay requirements of real-time multimedia packets. Figure 7 shows a comparison between our proposed protocol, SCMR, with the other protocols (DHCT, MCRA, and EDGE) in terms of average end-to-end delay with different node number. It can be seen clearly that our protocol outperform other protocols due to the hierarchical architecture of powerful cluster heads that always select the route with lowest number of hops of better link quality and hence minimum delay. \begin{table}
\begin{tabular}{l c} \hline \hline
**Parameter** & **Value** \\ \hline
**Simulation time** & 1000s \\ \hline
**Network size** & 500x500m\({}^{2}\) \\ \hline
**Node number** & 50 - 200 \\ \hline
**Link layer** & LL \\ \hline
**Maclayer** & IEEE802.1I \\ \hline
**IFQ type** & QueueDropTail/PrQueue \\ \hline
**IFQ length** & 10 \\ \hline
**Antenna type** & Antenna/OmiAntenna \\ \hline
**Physical type** & Phys/WirelessPhy \\ \hline
**Channel type** & Channel/WirelessChannel \\ \hline
**Energy model** & EnergyModel \\ \hline Bandwidth & 2 MB \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Simulation Parameters. Figure 7: End-to-End Delay of Our Protocol Compared with Other Protocols. In Figure 8, the mean throughput of our protocol is shown compared with the other protocols. The throughput is measured as the total number of packet received at the sink over the simulation period. Selecting multiple paths of better link quality and minimum delay leads to load balancing and efficient utilization of the wireless spectrum, and hence achieves higher throughput and much better performance than other protocols as seen in Figure 8.  
Figure 9 shows the average packet delivery ratio (PDR) of our protocol with different node number. PDR is measured as the total number of data packets received at the sink over the total number of data packets sent by all sources in the network. It is shown that our proposed protocol outperforms the other protocols, which confirms the previous result, due to the use of the 2 nd-level scheduling that prevents collisions and minimizes interference along with the selection of paths with better link quality based on the received signal strength (along with SNR and BER). Also, the use of the fast mechanism of local repair through the acknowledgment system minimizes the effects of any node failure or link break and hence decreases the number of lost packets. Figure 8: Throughput of Our Protocol Compared with Other Protocols. Figure 9: PDR of Our Protocol Compared with Other Protocols. Average energy consumption is shown in Figure 10 where we can realize that our proposed protocol SCMR has less energy dissipation comparing with other protocols (DHCT, MCRA, and EDGE) with different node numbers. This result due to the fact that most of the nodes in the clustered network are GMs and need only to communicate with their CHs regardless of the number of nodes in the cluster. In addition, the 2 nd-level scheduling prevents packet collisions and interferences and hence there is no need for retransmission lost packets.