## 6 Conclusions  
In this study, the adoption of link quality metrics in the OMNeT++ discrete event simulator was performed, using the new technologies of WuRx nodes in WSNs. WuRx nodes were chosen due to their energy efficiency and the absence of their consideration in the simulators, where simulation is important to reveal the response of new WuRx technologies in many different fields.  
The modeling of the PER was achieved through the testing and measurement of the impact of the attenuation on two radio chips, the SPIRIT1 transceiver and the COTS WuRx based on the LFPM AS3933.  
Both radios operate in the 868 MHz central frequency, and a specific data rate was considered for matching the LFPM AS3933 central operating frequency, which is 18.72 kHz with a specific address.  
Different levels of attenuation between the transmitter and the receiver were applied, due to the distinctions in the link budget of different radios. The main radio SPIRIT1 transceiver reached a \(-111.27\) dBm sensitivity. The WuRx based on the LFPM AS3933 reached a \(-59.55\) dBm sensitivity. The investigation showed the presence of a larger deviation in the SPIRIT1 transceiver than in the WuRx based on the LFPM AS3933, which split from the error function regression model, which was handled by the Weibull distribution. The distribution parameters were built using a ML algorithm that used nonlinear regression to generate a precise curve compared to the real experiment output. In the end, a different noise level was applied to determine the output signal at the end of the simulation.  
Finally, an accurate simulated model in OMNeT++ revealed the real reaction of the WuRx to different attenuation levels. This real-life simulation is a predeployment WSN-based WuRx for indoor applications. Many energy-efficient algorithms routing protocols supporting scalable WSN-based WuRx will be a matter of investigation in future works.  
M.K.B., conceptualization, methodology, original draft writing, visualization, editing, and funding acquisition; I.K., writing sections, reviewing, editing, and visualization; A.F. and F.D., writing paragraphs, reviewing, and editing. All authors have read and agreed to the published version of the manuscript.  
This work was funded by the German Academic Exchange Service (DAAD).  
We acknowledge support by the Open Access Publication Funds of HTWK Leipzig. This research was performed at the Leipzig University of Applied Science (HTWK). Theauthors would like to thank the German Academic Exchange Service (DAAD) for their financial support and their encouragement.  
**Conflicts of Interest:** The authors declare no conflict of interest.  
**Abbreviations**  
The following abbreviations are used in this manuscript:  
API application protocol interface  
ASIC application-specific integrated circuit  
BER bit error rate  
BIT bipolar junction transistor  
COTS commercialized off-the-shelf  
CW continuous wave  
ETX expected transmission count  
FSK frequency shift key  
GPS global positioning system  
GUI graphical user interface  
INI initialisation  
LF low frequency  
LFPM low-frequency pattern matcher  
LQI link quality indicator  
LQL link quality level  
MAC media access  
MCU microcontroller unit  
ML machine learning  
NED network description  
NS2 network simulator 2  
OLS ordinary least square  
OOK on-off keying  
OPNET optimized network engineering tools  
OMNeT++ objective modular network testbed in C++  
PER packet error rate  
PRR packet reception ratio  
RF radio frequency  
RSSI received signal strength indicator  
SER sequence error rate  
SNR signal to noise ratio  
SVM support vector machine  
TIA transimpedance amplifier  
TOSSIM tiny OS simulator  
WSN wireless sensor network  
WSNs wireless sensor networks  
WUC wake-up call  
Wupt wake-up packet  
WuRx wake-up receiver  
WuTx wake-up transmitter