## 2 Background and Related Works
### Energy Model Analysis  
Any process' general energy consumption, \(E\), is the power, \(P(t)\), that it consumes for a duration, \(T\). The general form of the energy consumption equation is shown in Equation (1); \(P(t)\) comes from \(V\times I(t)\), which is the multiplication of voltage, \(V\), and current, \(I(t)\). \[E=\int_{0}^{T}P(t)dt=V\int_{0}^{T}I(t)dt \tag{1}\]  
The life cycle of an IoT device is awakening from sleep mode, acquiring sensing value, processing the data point, and transmitting it through a wireless channel. This process is repeated over time, and the duty cycle plays a significant role in energy consumption: the smaller the duty cycle, the lower the average power consumption. Based on this assumption, the power needed to run an IoT device may be divided into three primary stages: data sensing or acquisition, \(P_{a}\); data processing or handling, \(P_{p}\); and data transmission or networking, \(P_{n}\). In addition, a tiny portion is reserved for system administration activities, including real-time operating system (RTOS) execution and system awakening on schedule, \(P_{s}\)[27]. The overall stage of the IoT device's operation for a cycle is shown in Figure 1.  
Figure 1 shows the characteristics of tasks and their duration time that depends on the application. From Equation (1), overall energy consumption is initiated as Equation (2),  
\[ \begin{split} E&=E_{idle}+E_{acq}+E_{proc}+E_{send} \\ &=\int_{0}^{T}[P_{idle}(t)+P_{acq}(t)+P_{proc}(t)+P_{send}(t)]dt \end{split}  \tag{2}\]  
Equation (2) shows the energy consumption of IoT devices during sensing and sending data via wireless transmission. Energy consumption models are proposed for node energy consumption [7; 27], and the wireless transmission module [28]. Moreover, the energy model is presented from the perspective of task scheduling. However, the wireless transmission module consumes the power 95% (\(E_{send}\)) while the node operation consumes 5% (\(E_{idle}+E_{acq}+E_{acq}\)). Most research on power models and energy-aware design has focused on transmission techniques or protocols. In addition, the process in one cycle consists of active, \(tACT\), and sleep, \(tSLP\), periods (\(tACT<tSLP\)). The active period consists of sensing state (\(t_{a}\)), processing state (\(t_{p}\)), and transmission state (\(t_{n}\)). Hence, the active period (\(tACT=t_{a}+t_{p}+t_{n}\)). Using low-power equipment and technologies and effective power management techniques may reduce the power consumption of both the node and the wireless transmission component. However, all scenarios encompass four distinct states: idle state (\(P_{idle}\)), data acquisition state (\(P_{acq}\)), processing state (\(P_{proc}\)), and network transmission state (\(P_{send}\)). Consequently,  
Figure 1: The power consumption of the node. we evaluate the current consumption. The energy consumed in the idle state (\(P_{idle}\)) and the processing state (\(P_{proc}\)) does not significantly impact the overall experiment. Let us define \(E_{node}\) as the integral of power consumption over time, represented by the equation \(E_{node}=\int_{0}^{T}\bigl{(}P_{idle}(t)+P_{proc}(t)\bigr{)}dt\). The energy consumption of the IoT device is divided into two parts: the sensing and transmission parts. The sensing part (\(E_{sense}\)) consists of the energy from node (\(E_{node}\)) and data acquisition state (\(E_{acq}\)). Hence, the energy model of the sensing part (\(E_{sense}\)) is  
\[ \begin{split} E_{sense}&=E_{node}+E_{acq}\\ &=\int_{0}^{T}\left(P_{node}(t)+P_{acq}(t)\right)dt\\ &=V\int_{0}^{T}\left(I_{node}(t)+I_{acq}(t)\right)dt,\end{split}  \tag{3}\]  
where the \(V\) represents the voltage of microcontroller unit (MCU) and sensor node while \(I(t)=I_{idle}(t)+I_{acq}(t)\) represents the current consumption of each module. Furthermore, we examine the energy consumption from the perspective of network transmission, \(E_{send}\). Therefore, the parameter, \(P_{send}\), is measured and compared across various scenarios.