# Multiparametric Monitoring in Equatorial Tomato Greenhouses (II): Energy Consumption Dynamics
## 4 Experiments and Results
### Energy Consumption Dynamics of WiFi Network
After a comparative study of the _pdf_ and CIs of the three networks, we conclude that the WiFi network exhibits relevant differences. In the Coordinator Node, the CIs were considerably narrow, the modes of the curve were easily distinguished, they do not vary sharply, and the range of the _pdf_ consumption values contained was high. In Node 1, the CI widths and the probability curves were similar, but the consumption values tend to be low. The _pdf_ in Nodes 2 and 3 differ with respect to the other two networks, because an additional mode was generated for consumption values lower than 0.04 mA, whose probability amplitude was considerable. This was likely produced by noise, and also the electrical current range with major occurrence probability was high. With respect to Node 4 of the DigiMesh network, the _pdf_ and the CIs at 19,200 and 57,600 bauds were very similar in form, but the average consumption was high, while at 9600 bauds the differences are noticeable in terms of the CI width and the number of modes. Figure 16: Time signals for WiFi network: (**Left**) at 9600 bauds; and (**Right**) at 57,600 bauds. From top to bottom: total time signal, time detail of the signal, and signal sections with closer detail. The estimation of the SAFs for the ten realizations revealed that the behavior of the functions for the Coordinator Node and for Nodes 1-3 is the same for the two speeds. Figure 20 shows some representative SAFs. The correlation of Node 1 falls slowly, with a slight persistence for the first 50 delays, its range was similar in all realizations and it was the highest with respect to the other nodes of this network. The SAFs in Sensor Nodes 2 and 3 were the same for both transmission rates, the fall was slow, and the persistence can be observed for delays less than 100. The correlation then decreases and reaches negative values near to zero with increasing delays. In this scenario, the relation between one observation and another was minimal and inverse. In the Coordinator Node, the SAF falls rapidly, the correlation was positive and it varies with persistence for all delays. However, its values were very low, therefore the relation between observations was very low even in the initial delays. In the case of Node 4, the SAF lacks persistence for both speeds, but the drop was less pronounced at 57,600 bauds and the increase in delays causes also a negative correlation. However, at the highest speed, we can see a slight increase for delays higher than 400, and if the delay continues to increase, the relation between observations tends to be high and direct. Figure 17: M-mode plots of the _pdf_ with particular characteristics: (**a**) DigiMesh Coordinator Node at 57,600 bauds; and (**b**) WiFi Coordinator Node at 57,600 bauds. Figure 18: Histograms for WiFi network: (**Left**) at 9600 bauds; and (**Right**) at 57,600 bauds. Figure 19: _Cont._  
By studying the average SAF and the CIs shown in Figure 21, and for both speeds, we complement the analysis of the energy consumption behavior of the elements of the network. The Coordinator Node was a seasonal process, given the rapid and persistent fall of SAF. For all sensor nodes, the processes were defined as non-seasonal, since the fall of the correlation coefficient was slow and it lacks persistence. Regarding the CIs, we conclude that, for Nodes 2-4, the widths were very small, and similar for the two transmission rates, while, in other network elements, we observe variations. For the highest speed, the CI amplitude increases in the Coordinator Node, and decreases in Node 1, but not in large magnitude, since the deviation does not exceed the 0.05. For Node 4, the fall of autocorrelation coefficient was more rapid, as well as its increase to delays greater than 400, particularities that were already explained. In general terms, the SAF average of each node defines with enough precision the presence or absence of seasonality in the signals, since the intervals were quite narrow.