Symmetric eigenfilters for partial shortening in ADSL DMT transceivers

A partial shortening method of equalization for xDSL is presented. The novel method is suitable for FDD systems, shortening the effective channel impulse response and, additionally, achieving out-of-band noise reduction. A family of solutions based on linear phase FIR equalizers is described. The mathematical framework for all symmetric filters is developed. Channel shortening and bit rate simulation results for several VDSL test loops, show that the novel method yields a similar performance and reduces the out-of-band noise, with a considerably lower mathematical complexity and a simpler implementation.