（1.State Grid Key Laboratory of Power Industrial Chip Design and Analysis Technology, Beijing Smart-Chip Microelectronics Technology Co.,Ltd.,Beijing 100192,China; 2.Beijing Engineering Research Center of High-Reliability IC with Power Industrial Grade, Beijing Smart-Chip Microelectronics Technology Co.,Ltd.,Beijing 100192,China）
Abstract： Large impulsive noise is common in lowvoltage power line channels,which poses a great challenge to the automatic gain control （AGC） of OFDM power line communication （PLC） systems.Based on the analysis of the structure of PLC system and the characteristics of impulse noise,this paper proposes a new method of AGC with strong anti impulsive noise capability.By embedding the impulsive detection circuit in the AGC,the method stops the gain adjustment when the impulsive noise or the system frame synchronization is detected,which can effectively prevents the AGC from malfunction caused by the impulsive noise,and reduces the interference of the impulse noise on the AGC during the receiving process.The simulation results show that the proposed AGC method can effectively improve the performance of PLC receivers.
Key words : power line communication;automatic gain control;impulsive noise;orthogonal frequency division multiplexing （OFDM）
0 引言
隨著泛在電力物聯(lián)網(wǎng)的全面部署，電力線通信（Power Line Communication,PLC）因其建設(shè)成本低、覆蓋范圍廣等優(yōu)勢(shì)，已成為電力本地通信中的主流技術(shù)。然而電力線最初是為輸送電能設(shè)計(jì)的，信道環(huán)境極其惡劣，表現(xiàn)為多徑干擾嚴(yán)重、衰減大、噪聲顯著，同時(shí)國(guó)內(nèi)外低壓電力線信道存在明顯差異，因此國(guó)內(nèi)自研開(kāi)發(fā)了相應(yīng)的高速電力線通信技術(shù)標(biāo)準(zhǔn)。自研標(biāo)準(zhǔn)采用正交頻分復(fù)用（OFDM）的多載波調(diào)制，結(jié)合改進(jìn)的信道編碼與分集拷貝技術(shù)，具有良好的抗多徑及噪聲特性，但OFDM系統(tǒng)本身的性能容易受接收信號(hào)功率的影響，且電力線信道中普遍存在較大的脈沖噪聲，這對(duì)電力線通信中的自動(dòng)增益控制（AGC）帶來(lái)了極大的挑戰(zhàn)。
