Research on AGC Optimal Reference Power in Broadband PLC Multipath Channel

Abstract

Intermediate frequency stably outputs with an Automatic Gain Control (AGC) loop in a broadband Power Line Communication (PLC) system. The AGC optimal reference power analysis which adopts amplitude distribution computation method aims to have an optimal Signal Noise Ratio (SNR) in a broadband PLC multipath channel. According to the amplitude of Orthogonal Frequency-Division Multiplexing (OFDM) signal obeying the Rician distribution, a series of different parameters that includes K ratio between Light of Sight (LOS) power and whole power, Analog to Digital Converter (ADC) reference level, ADC bits and AGC loop reference power are analyzed so as to obtain the AGC optimal reference power with different K value. A LOS transmission attenuation model and reflection signal transmission attenuation model are obtained by analyzing typical broadband PLC topology and signal transmission attenuation mode in a broadband PLC system. The K values in a 10 nodes broadband PLC system are simulated with the method of AGC optimal reference power in a broadband PLC multipath channel. According to K values in every node and optimal reference power formula, the optimal reference power and the highest ADC sampling bit are computed. The AGC optimal reference power which meets requirement of ADC sampling bits is effectively obtained through the simulation results.