Methods and apparatuses for data transmission

Abstract

Methods and devices are disclosed involving crosstalk reduction depending on weighting factors or grouping of transmission channels. In other embodiments, other methods or devices may be used.

1 . A communication device, comprising:
 communication circuitry configured to communicate via a plurality of transmission channels, wherein said communication circuitry comprises crosstalk reduction circuitry to reduce crosstalk for a part of said plurality of transmission channels by joint processing of data of said part of said transmission channels,   wherein said part is selected from said plurality of transmission channels depending on a grouping of said transmission channels into at least two groups.   
     
     
         2 . The communication device of  claim 1 ,
 wherein to each of said at least two groups a target bit rate is assigned, wherein the target bit rate for different groups differ.   
     
     
         3 . The communication device of  claim 2 , wherein said target bit rates comprises at least one fixed target bit rate and at least one variable target bit rate. 
     
     
         4 . The communication device of any one of  claims 1 - 3 , wherein said communication device is configured to select said part depending on a weighting vector describing relative target bit rates of the plurality of transmission channels. 
     
     
         5 . The communication device of device of  claim 1 , further comprising:
 transmission power control circuitry configured to control transmission power on said plurality of transmission channels depending on said grouping.   
     
     
         6 . The communication device of any one of  claims 1 - 5 , wherein said communication device is configured to select said part of said plurality of transmission channels depending on crosstalk strengths between said plurality of transmission channels. 
     
     
         7 . The communication device of device of  claim 1 , wherein said plurality of transmission channels are a plurality of xDSL communication lines. 
     
     
         8 . The communication device of device of  claim 1 ,
 wherein selecting said part comprises selecting far-end crosstalk branches between said communication channels based on said grouping, and   wherein reducing said crosstalk comprises reducing said crosstalk for said selected far-end crosstalk branches.   
     
     
         9 . A communication device, comprising:
 communication circuitry configured to communicate via a plurality of transmission channels, wherein said communication circuitry comprises crosstalk reduction circuitry to reduce crosstalk for a part of far-end crosstalk branches between said plurality of transmission channels by joint processing of data corresponding to said part of said far-end crosstalk branches,   wherein said part is selected depending on a grouping of said transmission channels into at least two groups.   
     
     
         10 . A communication device, comprising:
 a plurality of inputs to be coupled with a respective plurality of communication lines,   receive circuitry configured to obtain receive symbols based on data received via each of said plurality of communication lines,   a crosstalk canceller configured to combine receive symbols received via a part of said communication lines to generate crosstalk cancelled receive symbols, and   a control circuit configured to select said part of said communication line depending on a crosstalk strength between said communication lines and weight factors associated with said plurality of communication lines.   
     
     
         11 . The communication device of  claim 10 , wherein said control circuit is configured to select said part of communication lines as communication lines associated with crosstalk branches which have the highest crosstalk strength weighted with weighting factors of the communication lines associated with the crosstalk branch. 
     
     
         12 . The communication device of  claim 11 , wherein the communication device is configured to transmit on each of said plurality of communication lines data on a plurality of carriers, wherein a weighted crosstalk strength P_weight ji (k) for a carrier k of a crosstalk branch from a communication line j to a communication line i is calculated according to
     P _weight ji ( k )= P _fext ji ( k )· g   j   α   ·g   i   β 
   wherein P_fext ji (k) is the crosstalk power from communication line j to communication line i for carrier k, g j  is the weighting factor for line j, g i  is the weighting factor associated with line i and α and β are predetermined values, and wherein the control circuit is configured to select said part of said communication lines depending on said weighted crosstalk strengths.   
     
     
         13 . The communication device of  claim 12 , wherein β>1. 
     
     
         14 . The communication device of  claim 10 , wherein said control circuit is further configured to control transmit powers of signals received on said inputs depending of said weighting factors by controlling further communication devices connected to far ends of said communication lines. 
     
     
         15 . The communication device of  claim 10 , wherein said weighting factors represent relative bit rates, and wherein said transmission powers are adjusted such that transmission rates obtained on said plurality of communication lines match the relative bit rates. 
     
     
         16 . A method comprising:
 defining weighting factors for a plurality of transmission channels,   determining crosstalk strength between said plurality of transmission channels,   selecting a part of the plurality of transmission channels depending on said crosstalk strength and depending on said weighting factors for crosstalk reduction, and   communicating data via said plurality of transmission channels using crosstalk reduction for said part of said plurality of transmission channels.   
     
     
         17 . The method of  claim 16 ,
 wherein said weighting factors indicate relative target bit rates for said plurality of communication channels.   
     
     
         18 . The method of  claim 16 ,
 wherein said weighting factors comprise at least one fixed weighting factor and at least one variable weighting factor.   
     
     
         19 . The method of  claim 18 ,
 further comprising adjusting said variable weighting factor such that bit rate ratios defined by said at least one fixed weighting factor are fulfilled.   
     
     
         20 . The method of  claim 16 ,
 further comprising performing a spectrum balancing for said plurality of transmission channels depending on said weighting factors.   
     
     
         21 . The method of  claim 16 ,
 wherein selecting said part comprises selecting far-end crosstalk branches between said communication channels based on said grouping, and   wherein said using of crosstalk reduction comprises reducing said crosstalk for said selected far-end crosstalk branches.