PLC (Power Line Communication) is a communication method that uses power lines to transmit data and voice signals. PLC technology and its working principle: PLC (Power Line Communication) is a communication method that uses power lines to transmit data and voice signals. To date, PLC technology has a history of several decades, and at various stages of its development, it has found different applications in power systems. In various fields of high-voltage transmission networks (above 35kV), medium-voltage transmission networks (10kV-35kV), and low-voltage (below 10kV), the data transmission rate has been continuously increasing. Currently, in low-voltage distribution networks, the transmission rate has developed from 1Mbps to 2Mbps, 14Mbps, 24Mbps, 45Mbps, and even reached high speeds of 100Mbps and 200Mbps, with transmission distances reaching 300 meters. In the field of medium-voltage distribution network transmission technology, the concept and solutions for data signals exceeding 10Mbps have also attracted increasing attention and have been successfully developed. The working principle of a PLC: Power lines are extremely unstable transmission channels with high noise and strong attenuation. To achieve reliable high-speed data communication over power lines, it is necessary to address the impact of various factors on data transmission in low-voltage distribution networks, such as noise, impedance fluctuations, network structure, electromagnetic compatibility, and signal attenuation caused by line impedance and capacitive loads. To address the impact of these factors on data transmission in low-voltage distribution networks, orthogonal frequency division multiplexing (OFDM) technology is widely adopted internationally as the core modulation technique for high-speed data communication in low-voltage distribution networks. OFDM technology uses multiple narrowband orthogonal subcarriers to transmit multiple data streams simultaneously. Each signal has a longer symbol time, which avoids inter-symbol interference. By dynamically selecting available subcarriers, this technology can reduce narrowband interference and the impact of frequency valleys. OFDM technology originated in the 1960s and was primarily used in military high-frequency communication systems. In the 1970s, with the introduction of Discrete Fourier Transform (DFT) for multi-carrier modulation and the rapid development of Digital Signal Processing (DSP) technology in recent years, OFDM, as a high-speed transmission technology that can effectively combat interference between signal waveforms, has been widely used in civilian communication systems. Currently, this technology is used in wireless local area networks (WLANs), and OFDM will be used in fourth-generation mobile communication (4G). Several Access Schemes for PLCs In low-voltage power distribution network data transmission systems, a typical system consists of a headend (HE) and a customer end (CE). The headend is generally installed at the low-voltage outgoing line of the distribution transformer, primarily responsible for converting between PLC high-frequency signals and traditional broadband communication signals. One side of the PLC headend is connected to the power cable via a capacitor or inductor coupler to inject and extract high-frequency PLC signals; the other side connects to the Internet via traditional telecommunications access methods such as xDLS, fiber optic, or Ethernet. The customer end device, called a "powerline adapter," mainly consists of three parts: an interface, a modem, and a coupling device. The user's computer connects to the powerline adapter via an Ethernet or USB interface, and a regular telephone connects via an RJ-11 interface. Enables high-speed internet access, IP telephony, and IP video, among other multimedia access services.