## 4 Results and Discussion
### Overview of Simulation Results  
The performance of the network and individual sensor nodes is evaluated based on the number of uniquely received packets and the mean ratio of the number of uniquely received packets on the gateway to the uniquely transmitted packets per node, i.e., the data extraction rate. This indicates how reliably the intended payload bytes are received by the gateway. Moreover, this differs from the packet delivery success ratio because it does not include retransmissions in the calculation. Hence, the main objective is that the intended payload is received by the gateway, while the number of retransmissions necessary to \begin{table}
\begin{tabular}{c c c} \hline \hline
**Packet Payload in Bytes** & **Maximal Total Packet Size in Bytes** & **Transmission Rate per Hour** \\ \hline
6 & 14 & \(0.19\times 10^{-3}\) \\
11 & 19 & \(0.25\times 10^{-3}\) \\
51 & 59 & \(0.79\times 10^{-3}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Packet payloads. achieve this goal is of secondary importance. The collected results of the simulation process are presented and compared hereafter. According to the results presented in Figure 6, it can be observed that the substantial energy in the transmit (Tx) and receive (Rx) states can be reduced by disabling confirmed messages. In addition, since analyzing energy consumption optimization regarding the reduction in acknowledged transmissions, the impact of the duty cycle limit on the downlink capabilities of the gateway is also considered. The gateway cannot acknowledge all confirmed messages if only the default channels are utilized. Consequently, the number of retransmitted packages increases. Regarding the collected results for the deployed LoRaWAN sensor network scenarios, it can be concluded that the number of acknowledged frames must be minimized as much as possible to avoid capacity and energy drain. The communication channel variance, measured in dB, concerning the average path loss, i.e., path loss variance (PLV), is a consequence of varying propagation characteristics of the signal in space and time. As presented, the channel dynamics significantly impact the performance of a LoRaWAN network and the energy efficiency of the nodes. In general, the following can be stated. First, the ADR mechanism attempts to achieve a robust signal while considering energy consumption. This is achieved by lowering the data rate when the channel conditions worsen and increasing the data rate when the SNR conditions improve. According to the results presented in Figure 7, it is evident that ADR should be used in the analyzed scenarios since substantial energy savings can be achieved by enabling ADR. ADR reduces the energy consumption of the sensor nodes. First, it optimizes the LoRa parameters in such a way that nodes do not transmit with more power than needed. Secondly, this inherently diverges the utilized spreading factors, yielding fewer collisions. This demonstrates the importance of including ADR in assessing and optimizing transmission parameters in LPWANs to ensure a long battery life of sensor nodes. Figure 6: TxRx energy consumption per unique packet of one sensor node. However, ADR reacts slowly in situations with many devices or when a significant channel variance is present. The current ADR mechanism is unable to adjust for rapid channel variances. This effect is negligible if confirmed messages (i.e., retransmissions) are employed to ensure receiving each intended message. If no acknowledgments are used, the data extraction rate decreases when the channel variance increases. The nodes are unable to adapt adequately to the channel. Concerning the data extraction rate, it is better not to enable an adaptive data rate when not using confirmed messages. However, this results in higher energy consumption. Despite the beneficial effects of increasing the payload size, sending more bytes per packet increases the total number of bytes sent redundantly.