# Wake-Up Receiver-Based Routing for Clustered Multihop Wireless Sensor Networks
## 5 Experimental Setup and Measurement
### Performance Evaluation
The measurement results for the different strategies with two relay nodes are shown in Figure 13. It can be seen that the proposed approach has the best efficiency in terms of energy consumption in almost all sensor nodes. The exception is Relay 1. The reason for this is that Relay 1 is woken up at the same time as Relay 2 and the destination in the sense of simultaneous multicast wake-up. This means that Relay 1 remains in the receive mode for a certain time until it receives the DataPt. The behaviour is similar with SBS. As far as Relay 1 is concerned, NTN is the strategy that is very energy efficient. This is due to the fact that with the NTN strategy the sensor nodes wake each other up one after the other. Thus, the relay is only woken up for on-demand and never remains in receive mode unnecessarily. Figure 14 shows the according time in active mode. The specific results can be found in Tables 4 and 5. Figure 11: Measured energy consumption of every single node using 1 Relay. Figure 12: Measured time of every single node in active mode using 1 Relay. Figure 14: Measured time of every single node in active mode using 2 Relays. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Relay**} & **Proposed Approach CWM** & **SBS** & **NTN** \\  & **mAs** & **mAs** & **mAs** \\ \hline Sink & 1.16 & 1.47 & 1.56 \\ Fog Node & 1.65 & 1.96 & 1.96 \\ Relay 1 & 0.48 & 0.78 & 0.45 \\ Destination & 0.22 & 0.23 & 0.44 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Single nodes energy consumption using 1 Relay. Figure 13: Measured energy consumption of every single node using 2 Relays. The maximum number of relays considered within this study was three cluster nodes. The corresponding result of this measurement is shown in Figure 15. As with the previous results, a similar behaviour can be seen with regard to the consumed energy. In our proposed approach it is particularly notable that Relay 1, i.e., the node that sends the DataPt to the Fog Node last, always consumes the most energy. As described earlier, this is due to the time the node waits for a DataPt in receive mode. This is where NTN's strategy shows its strength, that relays are only woken up when they are needed. The SBS approach clearly shows how long waiting in receive mode affects energy consumption. The same behavior as in previous measurements can also be seen in the course of the active states of the individual nodes over time presented in Figure 16. The specific results can be found in Tables 6 and 7. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Relay**} & **Proposed Approach CWM** & **SBS** & **NTN** \\  & **mAs** & **mAs** & **mAs** \\ \hline Sink & 1.74 & 2.55 & 2.57 \\ Fog Node & 2.26 & 3.16 & 3.22 \\ Relay 1 & 1.05 & 2.04 & 0.45 \\ Relay 2 & 0.82 & 1.33 & 0.66 \\ Relay 3 & 0.52 & 0.80 & 0.68 \\ Destination & 0.22 & 0.23 & 0.44 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Single nodes energy consumption using 3 Relays. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Relay**} & **Proposed Approach CWM** & **SBS** & **NTN** \\  & **mAs** & **mAs** & **mAs** \\ \hline Sink & 107.30 & 133.70 & 135.05 \\ Fog Node & 112.58 & 139.39 & 139.46 \\ Relay 1 & 55.26 & 78.69 & 48.14 \\ Destination & 30.85 & 28.86 & 55.62 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Single nodes time in active mode using 1 Relay. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Relay**} & **Proposed Approach CWM** & **SBS** & **NTN** \\  & **mAs** & **mAs** & **mAs** \\ \hline Sink & 1.41 & 1.98 & 2.01 \\ Fog Node & 1.85 & 2.50 & 2.56 \\ Relay 1 & 0.82 & 1.32 & 0.45 \\ Relay 2 & 0.48 & 0.78 & 0.68 \\ Destination & 0.22 & 0.23 & 0.46 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Nodes energy consumption using 2 Relays.