## 3 Study of the Pivotal Factors
### IEEE 802.15.4 Hopping Design Method
#### 3.2.2 RX Terminal  
The operation of the receiver entails an inverse transposition process relative to that of the transmitter. The signal's progression is illustrated in Figure 16.  
A Phase-Locked Loop (PLL) is employed to manage the synchronization aspect of the circuit, as depicted in the CRC-16 circuit block diagram illustrated in Figure 17 [30; 31]. The received I-phase and Q-phase signals undergo error correction testing. Subsequently, the data are meticulously restored to their original 16-bit forms. Following this restoration, the data can be subjected to half-sine wave shaping and OQPSK modulation, a technique akin to MSK modulation. A schematic for the MSK receiver is elegantly illustrated in Figure 18 [29; 32; 33]. Upon receiving the meticulously restored CRC-16 data, they are delicately fed into the OQPSK decision circuit for discernment. Following this, they are elegantly integrated into a 32-bit sequence of data, thus enabling the transition from chip to symbol. The waveform of this chip-to-symbol conversion is gracefully depicted in Figure 19 [34]. Figure 16: Receiver signal flowchart. Figure 17: Polynomial division processing diagram. Figure 18: MSK receiver processing diagram. Figure 15: CRC-16 encoder calculation result. In accordance with the exposition of the aforementioned core technology [35], the pivotal aspects for integration into the comprehensive framework of the operational system encompass two fundamental elements:  
1. The control apparatus for communication nodes. 2. The seamless incorporation of repeater units for advanced signal expansion. 3. The salient features encapsulated within these utilization directives are expounded as follows: * Possess a robust waterproof rating of IP67, designed for outdoor applications with inherent waterproofing. * Operate on an electrical supply ranging from AC 90 V to 220 V (non-waterproof), tailored for the purpose of linking with intelligent timepieces and the CHT mobile network. * Facilitate connectivity with a maximum of 32 intelligent timepieces. * Adhere to the Taiwan standard double-hole plug design (for outdoor use, paying meticulous attention to waterproofing is advised). Establish seamless communication between the control apparatus for communication nodes (CNs) and smart meters within a range of less than 40 m, as elegantly illustrated in Figure 20.  
The repeater device has the following features:  
* Possesses an impermeable IP67 rating, meticulously crafted for outdoor deployment, rendering it inherently waterproof. * Operates on an electrical supply spanning AC 90 V to 220 V, with a design tailored for non-waterproof environments. * Serves the noble purpose of extending the communication range between smart meters and a communication node control apparatus (it is imperative to note that this does not augment the capacity for smart meter connections). * Adheres to the Taiwanese standard double-hole plug configuration (for outdoor usage, vigilance toward waterproofing is advised). Figure 19: Chip-to-symbol timing diagram. Figure 20: Communication node control device. Ensures seamless communication, spanning over 40 m, from the communication node control apparatus to the smart meter, as elegantly depicted in Figure 21.  
The harmonious integration of these two apparatuses bestows upon the communication node control device a sphere of influence spanning 40 m from its epicenter. Within this expansive realm, it graciously accommodates all transmissions from the ensemble of smartwatch communication modules. Remarkably, each communication node control device yields the capacity to adroitly oversee as many as 32 smartwatches concurrently. Should the demand for control exceed this threshold, the judicious addition of supplementary communication node control devices is requisite. Furthermore, in scenarios where the count of smart meters falls beneath the threshold of 32, yet the radius emanating from a communication node control device surpasses 50 m, the intervention of a repeater device becomes imperative.