# Transmission Power Control in Wireless Sensor Networks Using Fuzzy Adaptive Data Rate
## 4 Experimental Results and Discussions
### Experimental Results  
The experimental results are presented in Table 8. In addition to the experimental data, the table briefly describes the interferences at each experimental location. The long-term test results indicate that the overall PER statistical results of the experimental group all converged to approximately 1% of the control target, whereas the control group with a fixed data rate and transmission power has different PER performance owing to environmental interference. In general, the sensor nodes in other positions are relatively power-saving in terms of the overall average current, except for sensor nodes 5 and 6 that have less power-saving effect; their power consumption is quite similar. When the experimental group is in good communication quality, it will reduce power consumption as much as possible so that RSSI is close to sensitivity; however, when the experimental group is in the bad communication quality, it will increase power consumption appropriately to keep RSSI away from sensitivity to obtain better communication quality. Figure 11 illustrates the long-term test results of sensor nodes 1 and 2 in the experimental and control groups, respectively. This position is the farthest from the bridge. The PER of the experimental group is 1.04%, and the location is interfered with by people walking around. However, the data rate and transmission power are appropriately adjusted by the algorithm so that the RSSI changes are similar in the daytime and at night. The PER of the control group is approximately 0.07%, and is located at the entrance of the first floor; therefore, there are several people walking around and this will cause interference, which leads to obvious differences in RSSI between the daytime and night. The RSSI in the daytime changes drastically; however, the RSSI at night has negligible change because there are fewer people walking around at night. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Node No.** & **Data Rate** & **Transmission Power** \\ \hline
1, 3, 5, 7, 9 & Adjust according to the algorithm \\
2 & 8 dBm & 200 kbps \\
4 & 9 dBm & 100 kbps \\
6 & 8 dBm & 400 kbps \\
8 & 5 dBm & 450 kbps \\
10 & 10 dBm & 400 kbps \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Data rate and transmission power of sensor nodes. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Node** & **PER** & \begin{tabular}{c} **Average** \\ **Transmission** \\ **Current (\(\mu\)A)** \\ \end{tabular} & \
\begin{tabular}{c} **Overall** \\ **Average** \\ **Current (\(\mu\)A)** \\ \end{tabular} &
\begin{tabular}{c} **Briefly Describe the Effects of Interference** \\ \end{tabular} \\ \hline
1 & 1.04\% & 0.71 & 19.49 & It is at the entrance of the first floor and farthest from the bridge. It is more obviously affected by people walking around. \\ \hline
3 & 0.77\% & 1.02 & 20.09 & It is in the stairwell and people walk around. The elevator also \\
4 & 1.51\% & 2.33 & 23.30 & starts and stops, causing interference. \\ \hline
5 & 1.03\% & 0.66 & 19.46 & It is outside the office and is more obviously affected by people \\
6 & 0.40\% & 0.56 & 19.25 & walking around during the day. \\ \hline
7 & 0.42\% & 0.30 & 18.86 & It is on the same floor as the bridge and few people will pass by. \\
8 & 1.52\% & 0.42 & 19.02 & It is on the same floor as the bridge and few people will pass by. \\ \hline
9 & 1.22\% & 0.59 & 19.24 & It is outside the classroom and there are some people who walk \\
10 & 0.46\% & 0.63 & 19.31 & around occasionally. \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Statistics of each sensor node. Regarding the current consumption, the average transmission and overall average current of the experimental group is approximately 0.71 and 19.49 \(\upmu\)A, respectively, whereas the average transmission and overall average current of the control group is approximately 1.12 and 20.57 \(\upmu\)A, respectively. The experimental group saves the average transmission current and is approximately 36.01%, whereas the overall average current is approximately 5.26%.