# Wake-Up Receiver-Based Routing for Clustered Multihop Wireless Sensor Networks
## 5 Experimental Setup and Measurement
### Performance Evaluation
This is due to the fact that the simultaneous wake-up of the sensor nodes used for data transmission takes place at the same time, which saves time and leads to direct data transmission as soon as the destination node is awakened. Considering the results of SBS strategy, which allows sequential sending of the WuPts, an increased time demand is required compared to our strategy. This is based on sending the WuPts one after the other. Depending on the number of relays, a corresponding number of WuPts are required to enable data transmission. This frequent sending, therefore, leads to an increased delay. For the NTN strategy, the destination node is woken up directly, and each of the relays must send WuPt in addition to the actual data packet. This increased sending of packets leads to an increased delay in data communication. The aforementioned results show the superiority of our approach that offers the best trade-off between time-efficiency and energy optimisation. Regardless of the number of relays, our approach delivers the best result in all measurements. However, the greater the number of relays increases, the more the clearer and more significant the advantages of our approach become. Particularly in time-critical applications such as medical, monitoring, and alarm situations in the home area, the advantages of our approach become apparent. In the following, we study the lifetime of our CWM protocol as well as the two other strategies. The lifetime in our scenario is the time needed until the first node in the network  
Figure 18: Routing latency with respect to the number of relay nodes comparing the 3 strategies. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Relay**} & **Proposed Approach CWM** & **SBS** & **NTN** \\  & **ms** & **ms** & **ms** \\ \hline
1 Relay & 107.30 & 133.70 & 135.05 \\
2 Relays & 130.46 & 183.55 & 184.34 \\
3 Relays & 154.80 & 233.50 & 235.43 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Time consumption related to the number of relay nodes comparing the 3 strategies. is out of energy. The battery-powered cluster nodes are powered by a standard CR2032 coin cell with a capacity of 240 mAh at 3 V. With an occurrence of events every 3 min; the lifetime for our proposed approach in the scenario with only 1 relay is 10.27 years, for SBS 6.32 years, and for NTN 10.96 years. Increasing the number of relays to two results in a lifetime of 6.01 years for our proposed approach, whereas SBS results in 3.74 years and NTN in 7.25 years. With the maximum number of relays considered in this work, three relays, the lifetime was 4.70 years with our proposed approach, 2.42 years for SBS, and 7.25 years for NTN. Considering the time required for data communication with the individual strategies, our proposed approach outperforms the other strategies by offering the best trade-off between energy efficiency and delay minimisation. The delay minimisation of our strategy was 19.75% for SBS and 20.55% for NTN. Even when using two relays, our approach has an advantage of 28.92% over SBS and 29.23% over NTN. With three relays, our approach had a delay minimisation of 33.7% compared to SBS and 34.25% compared to NTN.