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Downlink crosstalk elimination method for very-high-bit-rate digital subscriber loop (VDSL) system

A crosstalk elimination and user-friendly technology, applied in baseband system components, line fault/interference reduction, shaping network in transmitter/receiver, etc., can solve problems such as large system overhead and increase user-side feedback, and achieve Effect of reducing system overhead

Inactive Publication Date: 2012-02-15
BEIJING UNIV OF POSTS & TELECOMM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Channel information can be obtained through feedback from the user end, but the amount of feedback from the user end is increased, which brings a lot of system overhead

Method used

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  • Downlink crosstalk elimination method for very-high-bit-rate digital subscriber loop (VDSL) system
  • Downlink crosstalk elimination method for very-high-bit-rate digital subscriber loop (VDSL) system
  • Downlink crosstalk elimination method for very-high-bit-rate digital subscriber loop (VDSL) system

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Embodiment Construction

[0018] Due to the existence of crosstalk, each access point of the Central Office (central office) in the VDSL system is equivalent to a MIMO (Multiple Input Multiple Output) system between each access point and the user end. Therefore, in the embodiment of the present invention, there will be a CentralOffice with crosstalk The VDSL system composed of each access point and user end of the network is called a MIMO-DSL (Multiple-Input Multiple-Output-Digital Subscriber Line) system. MIMO-DSL systems such as figure 1 As shown, assuming that there are M clients, the channel matrix H is an M×M matrix, which can be expressed as:

[0019] H=[h 1 , h 2 ,...,h M ] T

[0020] Among them, h m =[h m1 h m2 ... h mM ](m=1, 2, ..., M) is a 1×M row vector, which is equivalent to the user channel corresponding to the mth user end, h mn (m±n) is the crosstalk from pair #n to pair #m.

[0021] A method for eliminating downlink crosstalk in a VDSL system provided by an embodiment of th...

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Abstract

The invention discloses a downlink crosstalk elimination method for a very-high-bit-rate digital subscriber loop (VDSL) system. The method comprises that: a user performs channel estimation on a corresponding user channel; the user acquires a downlink crosstalk coupling loss degree according to a channel estimation result; the user compares the downlink crosstalk coupling loss degree with a preset threshold value; if the downlink crosstalk coupling loss degree is lower than the threshold value, the user quantifies the user channel and feeds quantified channel information back; if the downlink crosstalk coupling loss degree is more than or equal to the threshold value, the user does not quantify the user channel; if all users feed the quantified channel information back, a transmitter calculates a pre-coding matrix according to the quantified channel information fed back by the users, otherwise calculates the pre-coding matrix according to a random codebook; and the transmitter performs crosstalk elimination processing on a downlink signal according to the calculated pre-coding matrix. By the technical scheme provided by the embodiment of the invention, system overhead caused by the feedback of the channel information can be effectively decreased.

Description

technical field [0001] The embodiment of the present invention relates to the field of wired communication, in particular to a method for eliminating downlink crosstalk in a VDSL system. Background technique [0002] Since the VDSL (Very-high-bit-rate Digital Subscriber loop, very high-speed digital subscriber loop) system has a wide frequency band, the crosstalk between the line pairs is relatively serious, especially in short-distance transmission, crosstalk has become an influence on transmission The main factors of speed and transmission distance. Crosstalk between wire pairs can be divided into "near-end crosstalk (NEXT)" and "far-end crosstalk (FEXT)". Since the VDSL system adopts FDM (Frequency-division multiplexing, frequency-division multiplexing) technology, the influence of NEXT can be eliminated or greatly reduced through filters, but FEXT and the interfered signal at the receiving end generally cannot be separated in the frequency band, and filtering cannot be ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L25/03H04L25/02H04L25/08
Inventor 李香雪刘丹谱李剑峰尹长川郝建军罗涛乐光新
Owner BEIJING UNIV OF POSTS & TELECOMM