MMSE-Based Partial Crosstalk Cancellation for Upstream VDSL

Abstract

In current DSL systems, crosstalk is a major problem. In the case of in-domain crosstalk and AWGN, it has been shown that the crosstalk can be effectively mitigated using a linear zero-forcing canceler. Furthermore, the complexity can be reduced by only canceling the crosstalk from major crosstalkers on each tone, which is reffered to as partial cancellation. However, such approach does not work e.g. in the case of alien crosstalk. As alien crosstalk is spatially correlated, the zero-forcing canceler performs very poorly, hence an alternative linear canceler has to be examined. In this paper, we demonstrate that an MMSE crosstalk canceler provides much improved performance than the zero-forcing canceler in this scenario and additionally, we also present an efficient algorithm to perform partial MMSE partial cancellation.

Iterative Receiver Based on SAGE Algorithm for Crosstalk Cancellation in Upstream Vectored VDSL

“…As stated earlier, it requires additional computation of channel matrix inversions. Further, it has been shown in many publications [6,20] that linear receivers (ZF and MMSE) experience significant performance degradation in the presence of alien crosstalk. The SAGE algorithm can effectively mitigate the effect of alien crosstalk as discussed in next section.…”

Performance analysis of a common-mode signal based low-complexity crosstalk cancelation scheme in vectored VDSL

“…It is noted that noise is spatially correlated across TPs due to the introduction of crosstalk from an alien source [3]. When the ZF-based receiver [8] is applied after noise whitening, it suffers from a significant performance loss due to the ill-conditioning of the channel after the whitening process as discussed in [11]. Chen et al [10] have shown that a non-linear DFE-ZF can achieve data rate higher than a ZF receiver, though with an increase in computational complexity.…”

“…In our previous study [9], we have shown that the SAGE based iterative receiver can effectively cancel the alien crosstalk to achieve a higher rate (with a little extra complexity). The MMSE based receivers have been proposed in [11,12] as a tradeoff between rate and complexity by eliminating the use of a whitening filter.…”

Dynamic partial crosstalk cancellation resource allocation algorithms for DSL access networks

“…The vectored DSL system has been studied in [11][12][13][14][15][16]. In [12][13][14][15][16] simple linear zero-forcing crosstalk cancellation schemes have been proposed that reduce the crosstalk cancellation computational complexity by only removing the dominant crosstalk in the system. This is also referred to as partial crosstalk cancellation (PCC).…”

“…Vectored DSL is seen as a very promising technique, and is subject of a standardization procedure of *Correspondence: bli@esat.kuleuven.be 1 Department of Electrical Engineering (ESAT-SCD), Katholieke Universiteit Leuven, Leuven, Belgium Full list of author information is available at the end of the article the international telecommunication union (ITU) [9,10]. The vectored DSL system has been studied in [11][12][13][14][15][16]. In [12][13][14][15][16] simple linear zero-forcing crosstalk cancellation schemes have been proposed that reduce the crosstalk cancellation computational complexity by only removing the dominant crosstalk in the system.…”