# EEMIP: Energy-Efficient Communication Using Timing Channels and Prioritization in ZigBee
## 4 Results and Discussion
### Evaluation of Scenario A  
The results of the simulation for the nonbeacon ZigBee mode in communication without need for retransmissions are provided in Table 1. The first column represents a device identification number (four devices were simulated). The second column represents the average number of bytes processed by the end device during a simulation time of one hour. The last column represents the average number of packets processed by the end device during the simulation time. One can notice that each device processes the same amount of packets, but different amount of bytes. The reason is that each device produces different amounts of data (device with a higher ID sends more data), which are sent in a single packet.  
The results of the simulation for the EEMIP mode in communication without need for retransmissions are provided in Table 2. The table contains analogous values as Table 1; however, it contains results for various low-priority time intervals.  
Table 3 contains comparison of results obtained for the two simulation modes. It refers a difference in a number of processed bytes when using EEMIP method in comparison to the standard nonbeacon ZigBee communication.  
Based on the reported results for nonproblematic conditions, we can confirm that the EEMIP method sends less data than the standard nonbeacon ZigBee communication in most of the cases (by 8% in average). It means that it is more energy efficient in most of the cases. By lowering the time interval for low-priority data, the data are sent more frequently and the  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**End Device ID** & **Bytes** & **Packets** \\ \hline
1 & 55,680 & 3480 \\
2 & 76,560 & 3480 \\
3 & 97,440 & 3480 \\
4 & 118,320 & 3480 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Number of processed bytes in the nonbeacon ZigBee mode without retransmissions.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**End Device ID** & \multicolumn{2}{c}{**2 s Low-Priority Time Interval**} & \multicolumn{2}{c}{**3 s Low-Priority Time Interval**} & \multicolumn{2}{c}{**5 s Low-Priority Time Interval**} \\
**ID** & **Bytes** & **Packets** & **Bytes** & **Packets** & **Bytes** & **Packets** \\ \hline
1 & 64,140 & 5040 & 57,900 & 4560 & 52,440 & 4140 \\
2 & 78,900 & 5040 & 71,220 & 4560 & 64,500 & 4140 \\
3 & 93,660 & 5040 & 84,540 & 4560 & 76,560 & 4140 \\
4 & 108,420 & 5040 & 97,860 & 4560 & 88,620 & 4140 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Number of processed bytes in the EEMIP mode without retransmissions.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**End Device ID** & \multicolumn{2}{c}{**2 s Low-Priority**} & \multicolumn{2}{c}{**3 s Low-Priority**} & \multicolumn{2}{c}{**5 s Low-Priority**} \\
**Time Interval** & **Time Interval** & **Time Interval** & **Time Interval** \\ \hline
1 & +15.19\% & +3.99\% & \(-\)5.82\% \\
2 & +3.06\% & \(-\)6.97\% & \(-\)15.75\% \\
3 & \(-\)3.88\% & \(-\)13.24\% & \(-\)21.43\% \\
4 & \(-\)8.37\% & \(-\)17.29\% & \(-\)25.1\% \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparison of the two simulation modes without retransmissions.  
(additional packet headers) is increasing. After some threshold, we can notice that the end devices in the EMIP mode process more bytes than in the nonbeacon ZigBee mode (i.e., it is less power efficient). The EMIP method is, thus, beneficial for end devices with a higher amount of data (amount of data is increased with device ID; the end device with the ID of 4 saves the most energy) and with a greater difference between time intervals for low and high priority (when low-priority time interval of 5 s was used, the energy savings were the highest).