# Predictive Energy-Aware Routing Solution for Industrial IoT Evaluated on a WSN Hardware Platform
## 5 PEAR Solution: Hardware Integration and Results Evaluation
### The Multiple Profiles Test Series  
In what follows, the PEAR performance is evaluated based on two test scenarios employing two and three profile clusters, respectively. The PEAR impact in terms of energy balancing and predictability will be evaluated by comparing the results of similar tests with and without the energy balancing support. The scenario splits the 70 field devices in two profile clusters having the same publishing and network configuration. The clusters are differentiated based on the expected lifetime and number of field devices per cluster. The high-consuming cluster has the energy profile set to 400 DPDUs/min (i.e., one year lifetime) and the low consuming cluster has the energy profile set to 135 DPDUs/min (i.e., 3 years). One can observe from Table 2 that the three-year profile cluster having the energy margin of 20 DPDUs/min, does not reach stability and has a cluster overconsumption of 15.182 mWh/day. The two energy profiles reflect a corner case where the life expectancy difference between clusters is two years, and the low cluster could not respect the energy constraints using only within-cluster energy balancing. The first scenario further employs seven cluster configurations concerning the distribution of the field devices per each profile cluster to give a more comprehensive view on the PEAR impact. The field device distribution varies from fifty high-profile devices and twenty low-profile devices labeled as H50L20 to only five devices in the high in profile and 65 in the low-profile labeled as H05L65. The configurations are detailed in the Table 3.  
The Figures 10 and 11 represents the average field device consumption expressed in mWh/day for the PEAR and Non-PEAR variants of the H20L50 test. Moreover, the figures show the field devices distribution per cluster and their corresponding energy profile. The PEAR algorithm aims to provide predictable energy consumption by limiting the average energy consumption of each field device to respect the 12 months and 36 months cluster lifetime expectancy. The cluster lifetime is determined by the field device with the highest energy consumption therefore the overconsuming devices determine the noncompliance of \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Energy Profile** & **Energy Profile** & **Energy Margin** & **Number of Topology** & **Time to PEAR** \\
**[DPDUs/min]** & **[Months]** & **[DPDUs/min]** & **Changes** & **Stability** \\ \hline
100 & 48 & \(-\)20 & \(>\)400 & No stability \\
135 & 36 & 20 & \(>\)400 & No stability \\
170 & 30 & 50 & 240 & 708 \\
200 & 24 & 80 & 231 & 643 \\
250 & 19 & 130 & 32 & 87 \\
300 & 16 & 180 & 19 & 71 \\
400 & 12 & 280 & 7 & 31 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The number of topology changes and the time to stability. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Configuration** & **High Cluster Size** & **Low Cluster Size** & **High Cluster Size** & **Low Cluster Size** \\
**(1-Year Lifetime** & **(3 Years Lifetime** & **Distribution [\%]** & **Distribution [\%]** \\
**Cluster)** & **Cluster)** & **Distribution [\%]** & **Distribution [\%]** \\ \hline H50L20 & 50 & 20 & 71.43\% & 28.57\% \\ H40L30 & 40 & 30 & 57.14\% & 42.86\% \\ H30L40 & 30 & 40 & 42.86\% & 57.14\% \\ H20L50 & 20 & 50 & 28.57\% & 71.43\% \\ H15L55 & 15 & 55 & 21.43\% & 78.57\% \\ H10L60 & 10 & 60 & 14.29\% & 85.71\% \\ H05L65 & 05 & 65 & 7.14\% & 92.86\% \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The distribution of the field devices per each profile cluster. the entire cluster concerning lifetime. For the H20L50 test, PEAR stability state was reached in 346 min after triggering 47 network topology changes. Therefore, the three-year lifetime expectancy that could not be achieved on a single cluster basis was respected through PEAR intercluster energy balancing. Figure 11: Average field device energy consumption for all devices in the network differentiated by the energy profile when PEAR is disabled.