ADSL系统信道与回波冲激响应联合缩短算法研究

ADSL系统采用信息缩短的方法来抵消符号间干扰，同时由于环路线中回波干扰也比较严重，需要采用回波抵消措施。如果信道缩短和回波抵消分开进行，由于回波冲激响应长度很长，这必然增加回波抵消器的复杂性，继而影响ADSL系统的复杂性。使用最小均方误差准则，用一个FIR均衡器联合缩短信息与回波冲激响应，有效地缩短了回波和信道冲激响应长度。仿真结果表明，本算法在保持系统性能不变的前提下，降低了均衡器及回波抵消器的复杂度，是一种有效的算法。

Algorithm for Joint Shortening of Channel and Echo Response in ADSL system

While channel shortening is employed in ADSL system to cancel symbol interference,echo cancellation is required because of serious echo interference in loop lines.If channel shortening and echo cancellation are done separately,the echo suppressor will inevitably be made more complicated for the very long echo response.Both channel and echo response can be shortened at random with a single FIR equalizer by following the minimum mean square error rule.Simulation results indicate that this algorithm can reduce the complexity of equalizer and echo suppressor while the system performance is kept unchanged.