# A Distributed Sensor System Based on Cloud-Edge-End Network for Industrial Internet of Things +
## 3 System Model and System Architecture
### Wireless Communication Module  
The sensor module consists of multiple distributed sensors that are heterogeneous in nature. The module can gather data from various types of sensors, ensuring the reliability and richness of the data. By preprocessing and fusing different types of data, we can achieve more accurate results. For our study, we chose to use sound sensors and acceleration sensors,  
Figure 2: System model based on cloud-edge-end network. which we will experiment with, as outlined in [34]. To save channel resources and reduce costs, the local preprocessing and classification of sensor signals are necessary. The wireless signal \(s(k)\) received by the hotspot can be expressed as  
\[s(k)=x(k)+e(k),k=0,1,\cdots,N-1, \tag{1}\]  
where \(x(k)\)is the collected data transmission signal, which transmits binary data and artificial noise. The binary data signal is mainly composed of an amplitude modulation (AM) signal, frequency modulation (FM) signal, two-phase shift keying (2 FSK) signal, and four-frequency shift keying (4 FSK) signal. \(e(k)\) represents artificial noise in IDWSN and can be described as alpha-stabilized noise [35]. The wireless communication module uses the amplitude and phase of the electromagnetic wave to transmit information, including the binary data transmitted. Radio electromagnetic waves are a form of transmission of signals and energy that is used to transmit data between our sensors. The repeater receives the energy of the electromagnetic wave and obtains the transmitted binary data by identifying the amplitude and phase of the electromagnetic wave. The advantage of the AM signal is that the receiving equipment is simple, but the disadvantage is that the power utilization rate is low, the anti-interference ability is poor, and the frequency band utilization rate is not high. The AM signal can be expressed as  
\[w(t)=A\cos[2\pi f_{c}t+\phi(t)+\phi_{0}] \tag{2}\]  
where \(A\) represents the instantaneous amplitude of the signal, \(\phi_{0}\) denotes the modulation phase, \(f_{c}\) stands for the carrier frequency, and \(\theta\) is the carrier initial phase. The AM modulation signal can be represented as  
\[A=m_{0}+m_{t} \tag{3}\]  
where \(m_{T}\) is the baseband modulated signal of the signal, and \(m_{0}\) represents the dc component of the signal. The FM modulation signal is represented as  
\[A=1. \tag{4}\]  
Digital modulation has better anti-jamming performance, stronger anti-channel loss, and better security. Its baseband waveform can be expressed as  
\[w(t)=\sum_{n}a_{n}g(t-kT) \tag{5}\]  
where \(a_{N}\)is the symbol parameter sent by the transmitter, \(g(t)\)represents the equivalent filter module in the transmission process. MPSK signals can be written as  
\[w(t)=Ae^{i(2\pi f_{c}t+\varphi_{i})} \tag{6}\]  
where \(vaphi_{I}\) represents the phase modulation function and where the phase of the carrier is proportional to the instantaneous value of the modulated signal. The modulation function is given by  
\[\varphi_{i}=\frac{2\pi i}{M},i=0,1,\ldots,M-1. \tag{7}\]  
Multiamplitude shift keying (MASK) signals are a type of digital modulation technique that uses multiple amplitude levels to represent digital data. This technique is commonly used to transmit digital information over various communication channels, such as radio, optical, and coaxial cables. MASK signals are widely employed in wireless communication, satellite communication, digital TV broadcasting, and other similar applications. MASK signals are represented as  
\[w(t)=Ae^{i(2\pi f_{c}t)}. \tag{8}\]Multifrequency shift keying (MFSK) signals are a digital modulation technique that uses multiple frequencies to transmit data. This technique is a form of frequency shift keying (FSK), where each symbol is represented by multiple frequencies, enabling higher data rates than traditional FSK. MFSK signals are widely used in various applications, including radio communication, satellite communication, and digital audio broadcasting.