ADSL-DMT系统的子信道均衡算法仿真

在采用离散多载波调制(DMT)的ADSL中,需要使用均衡技术来缩短信道的响应时间,从而使系统发端可以采用长度较短的循环前缀来消除码间干扰。但传统的均衡算法复杂度高且对所有子信道做统一处理,限制了系统性能。针对这一问题,该文介绍了一种改进的结构———每个子音频信道上使用一个多抽头的频域均衡器,并通过仿真分析得到,该均衡器能够实现各个子信道的信噪比最大化,从而在相同传输条件下提高了系统容量,降低了系统对同步时延的敏感度,最后分析总结了该均衡器的简单初始化方法。

Simulation of Per Tone Equalization for ADSL-DMT

Time-domain equalizer is used in the discrete multitone-based ADSL system in order to reduce the duration of overall response of the transmission system,so that a shorter-length cyclic prefix could be used to eliminate intersymbol interference.However,traditional equalization technology is optimized over all subchannels with complicated computation,which limits the performance of ADSL.This paper introduces a new equalizer structure with a multitap FEQ per tone.With the simulation and analysis based on the new structure,the signal-to-noise ratio is maximized for each individual tone separately,and a larger bit rate is achieved while complexity during data transmission is kept at the same level.Moreover,the per tone equalization is shown to have a reduced sensitivity to the synchronization delay.At last,some cheap initialization schemes for PTEQ are also mentioned.