Abstract: To solve the problems of single and low rate of convolutional codes and large loss of data rate in the G3 standard, the low voltage power line carrier communication system model based on Orthogonal Frequency Division Multiplexing (OFDM) in the G3 standard was analyzed, and a designing scheme of forward error correction encoder was presented based on RS encoding, convolutional encoding, puncturing and depuncturing, repetition encoding and two dimensional time and frequency interleaving algorithm. Moreover, a method for raising the code rate by puncturing and depuncturing was mainly introduced. The simulation results show that the rate of convolutional codes is raised from 1/2 to 2/3, the data rate is improved without increasing the complexity of decoding, and the effective and reliable communication can be realized, which means the scheme can be widely used in low voltage Power Line Communication (PLC).

Key words: Orthogonal Frequency Division Multiplexing (OFDM), G3 standard, puncturing and depuncturing, code rate, forward error correction, Power Line Communication (PLC

摘要： 针对G3标准中卷积码的码率单一且码率较低，数据速率损失大的问题，分析了G3标准的正交频分复用(OFDM)低压电力线载波通信系统模型，提出了一种基于RS编码、卷积编码、增信删余编码以及重复编码和二维时频交织的前向纠错编码设计方案，并重点介绍了利用增信删余方式来提高码率的方法。最后通过对该方案的仿真实验得出，在该方案下卷积码的码率由1/2提高到了2/3,在不增加译码复杂度的情况下提高了数据速率，能够实现有效而可靠的通信，可广泛应用于低压电力线通信。

关键词: 正交频分复用, G3标准, 增信删余, 码率, 前向纠错, 电力线通信