## 6 Evaluation and Analysis
### Simulation Results
#### 6.3.3 Results of Different Protocol Sets  
This section evaluates different protocol sets based on different combinations of the MAC and NET layer protocols. A total of 9 protocol sets are defined as shown in Table 4. All sets are evaluated under normal traffic scenario with parameters as outlined in Table 2.  
Figure 14 shows the throughput of all the protocol sets. The largest performance differential among the protocol sets is a 64% increase in throughput by Set 9 over Set 1. Generally, it is observed that the throughput can be improved by replacing CSMA/CA with a DR-MAC based protocol. For instance, the throughput of Set 3 is improved by 36% over Set 1, 27% for Set 6 over Set 4, and 11% for Set 9 over Set 7. The less significant improvement for Set 9 over Set 7 could be due to that the context-aware DAAM has enhanced the delivery success of the sensor data packets, which leaves less room for further improvement by the context-aware DR-MAC. Figure 15 shows the PDR of all the protocol sets. It can be seen that the protocol sets with context-aware DAAM can achieve better PDR than the original DAAM under any MAC protocols, e.g., an improvement of 18% for Set 7 over Set 4, 14% for Set 8 over Set 5, and 11% for Set 9 over \begin{table}
\begin{tabular}{c c c} \hline Set & NET Layer Protocol & MAC Layer Protocol \\ \hline
1 & AODV & CSMA/CA \\
2 & AODV & DR-MAC \\
3 & AODV & DR-MAC (context-aware) \\
4 & DAAM & CSMA/CA \\
5 & DAAM & DR-MAC \\
6 & DAAM & DR-MAC (context-aware) \\
7 & DAAM (context-aware) & CSMA/CA \\
8 & DAAM (context-aware) & DR-MAC \\
9 & DAAM (context-aware) & DR-MAC (context-aware) \\ \hline \end{tabular}
\end{table} 
Table 4: Protocol sets. Figure 14: Throughput of the protocol sets. Set 6. There is a 61%, and 25%, improvement for Set 9 over Set 1, and Set 5, respectively. This result shows PDR can be improved by using AmI context information. Figure 16 compares the end-to-end delay. The result shows that the delay of Set 9 is reduced by 70%, and 46%, over Set 1, and Set 5, respectively. By replacing the non-context aware MAC with a context-aware version while keeping the same routing protocol, the delay can be reduced by 30% for Set 3 over Set 2, 29% for Set 6 over Set 5, and 22% for Set 9 over Set 8. By replacing the non-context aware routing with a context-aware version while keeping the same MAC protocol, the delay can be reduced by 26% for Set 7 over Set 4, 24% for Set 8 over Set 5, and 20% for Set 9 over Set 6. These results indicate that the delay can be reduced when exploiting the context information on the MAC and network layers. Figure 16: End-to-end delay of the protocol sets. Figure 15: PDR of the protocol sets. Figure 17 presents the average energy cost to successfully deliver a sensor data packet. In general, the protocol sets with DAAM-based routing cost more energy than those with AODV. This is due to the higher amount of energy used for transmitting control frames/packets. However, this higher energy use is partially offset by a larger number of sensor data packets delivered, resulting in only a moderate rise in the energy cost per packet delivered as compared to the protocol sets with AODV. The protocol sets with context-awareness are seen to achieve better energy efficiency. For instance, comparing Sets (3 and 2; 6 and 5; and 9 and 8) and Sets (7 and 4; 8 and 5; and 9 and 6) show that the energy cost per packet is reduced with context-awareness incorporated into the MAC, and network routing protocol, respectively. Figure 18 shows the communication overhead in terms of the number of control frames (MAC layer ACK frames) and control packets (routing-related control packets). The result shows that the protocol  
Figure 17: Energy cost of the protocol sets. Figure 18: Communication overhead of the protocol sets. sets with DAAM-based routing protocol have higher overhead than those with AODV. This is because unlike AODV, a route request (RREQ) packet cannot be discarded by any relay nodes during the path discovery phase in DAAM. Therefore, there are more RREQ packets being forwarded.