In this paper we analyze an adaptive downstream multichannel VDSL precoder that is based on error signal feedback. The analysis presents sufficient conditions for precoder convergence and an upper bound on the precoder steady state error. The paper also considers and analyzes the case of partial FEXT cancellation. The analysis shows that in some scenarios (and in particular in mixed-length binders) the use of partial FEXT cancellation is crucial to achieve precoder convergence in a reasonable time. Based on this analysis we determine that convergence is achievable in most practical channels. These bounds also allow for the proper setting of the convergence parameters. The paper presents several simulations to demonstrate the theoretical results. In these simulations, setting the precoder parameters according to the analysis leads to convergence in less than 400 OFDM symbols.
Bibliographical noteFunding Information:
This research was partially supported by a grant from the Israeli Ministry of Industry, Trade and Labor, as part of iSMART, the DSM consortium. Amir Leshem was partially supported by the Dutch Science and Technology Foundation under grant STW 10459. Digital Object Identifier 10.1109/TCOMM.2010.082010.090140
- crosstalk mitigation
- digital subscriber line
- linear precoding
- multichannel transmission
- vectored transmission