Performance Evalution of 2B1Q Data Echo Canceller in Digital Subscriber Access Networks

作     者：Tang Baomin (Nanjing University of Posts and Telecommunications, Nanjing 210003, P.R.China) 

出 版 物：《The Journal of China Universities of Posts and Telecommunications》 (中国邮电高校学报（英文版）)

年 卷 期：1997年第4卷第2期

页      面：68-71页

核心收录：

学科分类：0810[工学-信息与通信工程] 08[工学] 081001[工学-通信与信息系统] 

主　　题：digital communication access network echo cancellation 

摘      要：Recently, a lot of digital subscriber loop systems (DSL) and high rate digital subscriber loop systems (HDSL) have been deployed in digital subscriber access networks. Data echo canceller is extensively used in the DSL and HDSL systems to realize full duplex transmission on twisted cable. In such systems, 2B1Q line code is adopted. Therefore, symbol rate is decreased and digital transmission systems get longer reach. In this paper, a performance evaluation method of the echo canceller is proposed based on an autocorrelation matrix of 2B1Q line code. Using this method, the formula of ratio of data signal to echo residual signal is obtained. According to the formula, the ratio of data signal to echo noise depends on FIR filter tap, convergence factor, adaptive algorithm and the correlation matrix of the line code. Computer simulation is carried out to verify theoretical analysis. The simulation results coincided with the theoretical formula in the process estimating the ratio of signal to noise.