DSL transmission system with far-end crosstalk compensation
AssigneeSTMicroelectronics S.r.l.
InventorsTomas Nordstrom, Daniel Bengtsson, Olivier Isson
Life of this patent
Estimating the term…
Abstract
The invention relates to a far-end crosstalk canceling circuit for a digital subscriber line transmission system, the transmission system including a plurality of line termination modems transmitting discrete multitone symbols Si to corresponding network termination modems over n transmission channels. The invention multiplies the vector S=(Si) i=1 to n, before transmission, by a precompensation matrix M such that the matrix product H*M is diagonal, H being the transfer matrix of the plurality of downstream transmission channels defined by R=H*S where R=(Ri), i=1 to n, is the vector of the discrete multitone symbols Ri respectively received by the modems.
Claims33
A far-end crosstalk canceling circuit for a digital subscriber line transmission system, said transmission system comprising a plurality of line termination modems transmitting discrete multitone symbols to corresponding network termination modems over a plurality of transmission channels, comprising precompensation means multiplying, before transmission, a vector S=(Si), i=1 to n, by a precompensation matrix such that the matrix product H*M is diagonal, H being a transfer matrix of the plurality of transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the digital transmission symbols Ri respectively received by the modems.
A far-end crosstalk canceling circuit for a digital subscriber line transmission system, said transmission system comprising a plurality of line termination modems transmitting discrete multitone symbols to corresponding network termination modems over a plurality of transmission channels, comprising precompensation means multiplying, before transmission, a vector S=(Si), i=1 to n, by a precompensation matrix such that the matrix product H*M is diagonal, H being a transfer matrix of the plurality of transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the digital transmission symbols Ri respectively received by the modems;
- further comprising:
- storing means storing transfer matrices of the plurality of transmission channels at tones being defined by R(fj)=H(fj)*S(fj), where R(fj) is the vector R(fj) (Ri(fj)) i=1 to n and S(fj) is the vector S(fj)=(Si(fj)), i=1 to n, Ri(fj) and Si(fj) being the components at tone fj of the received discrete multitone symbol Ri and transmitted discrete multitone symbol Si respectively;
- and
- inversion means sequentially inverting said transfer matrices H(fj) and supplying the precompensation means with an inverted matrices H−1(fj), the precompensation means sequentially calculates the products H−1(fj)*S(fj).
A far-end crosstalk canceling circuit for a digital subscriber line transmission system, said transmission system comprising a plurality of line termination modems transmitting discrete multitone symbols to corresponding network termination modems over a plurality of transmission channels, comprising precompensation means multiplying, before transmission, a vector S=(Si), i=1 to n, by a precompensation matrix such that the matrix product H*M is diagonal, H being a transfer matrix of the plurality of transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the digital transmission symbols Ri respectively received by the modems;
- and
- a digital subscriber line transmission system comprising a plurality of line termination modems transmitting discrete multitone symbols Si to corresponding network termination modems over n transmission channels, comprising:
- the far-end crosstalk canceling circuit canceling far-end crosstalk at the network termination side of said system;
- and
- a line termination far-end crosstalk canceling circuit canceling far-end crosstalk at the line termination side of said system by estimating an inverse of the transfer matrix H−1up of the plurality of the transmission channels in an upstream direction, said line termination far-end crosstalk canceling circuit supplying an storing means of said far-end crosstalk canceling circuit with H=H−1up.
A far-end crosstalk canceling method for a digital subscriber line transmission system, said transmission system comprising a plurality of line termination modems transmitting discrete multitone symbols Si to corresponding network termination modems over n transmission channels, wherein a vector S=(Si), i=1 to n, is multiplied, before transmission, by a precompensation matrix M such that the matrix product H*M is diagonal, H being a transfer matrix of the n transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the discrete multitone symbols Ri respectively received by the modems.
A far-end crosstalk canceling method for a digital subscriber line transmission system, said transmission system comprising a plurality of line termination modems transmitting discrete multitone symbols Si to corresponding network termination modems over n transmission channels, wherein a vector S=(Si), i=1 to n, is multiplied, before transmission, by a precompensation matrix M such that the matrix product H*M is diagonal, H being a transfer matrix of the n transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the discrete multitone symbols Ri respectively received by the modems;
- wherein:
- transfer matrices H(fj) of the n transmission channels at tones fj are stored in storing means, H(fj) being defined by R(fj)=H(fj)*S(fj) where R(fj) is the vector R(fj)=(Ri(fj)), i=1 to n, and S(fj) is the vector S(fj)=(Si(fj)), i=1 to n, Ri(fj) and Si(fj) being the components at tone fj of the received discrete multitone symbol Ri and transmitted discrete multitone symbol Si respectively;
- said transfer matrices H(fj) are retrieved and inverted;
- the inverted matrices H−1(fj) are used as precompensating matrices at tones fj.
A far-end crosstalk canceling circuit for a data transmission system comprising a precompensation circuit multiplying, before transmission, a vector S=(Si), i=1 to n, by a precompensation matrix such that the matrix product H*M is diagonal, H being a transfer matrix of a plurality of transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the digital transmission symbols Ri respectively received by a modem.
A far-end crosstalk canceling circuit for a data transmission system comprising a precompensation circuit multiplying, before transmission, a vector S=(Si), i=1 to n, by a precompensation matrix such that the matrix product H*M is diagonal, H being a transfer matrix of the plurality of transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the digital transmission symbols Ri respectively received by a modem;
- further comprising:
- a storage circuit storing transfer matrices of the plurality of transmission channels at tones being defined by R(fj) H(fj)*S(fj), where R(fj) is the vector R(fj)=(Ri(fj)) i=1 to n and S(fj) is the vector S(fj)=(Si(fj)), i=1 to n, Ri(fj) and Si(fj) being the components at tone fj of the received discrete multitone symbol Ri and transmitted discrete multitone symbol Si respectively;
- and
- an inversion circuit sequentially inverting said transfer matrices H(fj) and supplying the precompensation circuit with the inverted matrices H−1(fj), the precompensation circuit sequentially calculating the products H−1(fj)*S(fj).
A far-end crosstalk canceling circuit for a data transmission system comprising a precompensation circuit multiplying, before transmission, a vector S=(Si), i=1 to n, by a precompensation matrix such that the matrix product H*M is diagonal, H being a transfer matrix of a plurality of transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the digital transmission symbols Ri respectively received by a modem;
- and
- a data transmission system comprising a plurality of line termination modems transmitting discrete multitone symbols Si to corresponding network termination modems over n transmission channels, comprising:
- a far-end crosstalk canceling circuit, canceling far-end crosstalk at the network termination side of said system;
- and
- a line termination far-end crosstalk canceling circuit canceling far-end crosstalk at the line termination side of said system by estimating an inverse of the transfer matrix H−1up of the plurality of the transmission channels in an upstream direction, said line termination far-end crosstalk canceling circuit supplying an storage circuit of said far-end crosstalk canceling circuit with H=H−1up.
A far-end crosstalk canceling method for a data transmission system, said data transmission system comprising a plurality of line termination modems transmitting discrete multitone symbols Si to corresponding network termination modems over n transmission channels, wherein a vector S=(Si), i=1 to n, is multiplied, before transmission, by a precompensation matrix M such that the matrix product H*M is diagonal, H being a transfer matrix of the n transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the discrete multitone symbols Ri respectively received by the modems.
A far-end crosstalk canceling method for a data transmission system, said data transmission system comprising a plurality of line termination modems transmitting discrete multitone symbols Si to corresponding network termination modems over n transmission channels, wherein a vector S=(Si), i=1 to n, is multiplied, before transmission, by a precompensation matrix M such that the matrix product H*M is diagonal, H being a transfer matrix of the n transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the discrete multitone symbols Ri respectively received by the modems;
- and
- further comprising:
- for transfer matrices H(fj) of the n transmission channels at tones fj , H(fj) being defined by R(fj)=H(fj)*S(fj) where R(fj) is the vector R(fj)=(Ri(fj)), i=1 to n, and S(fj) is the vector S(fj)=(Si(fj)), i=1 to n, Ri(fj) and Si(fj) being the components at tone fj of the received discrete multitone symbol Ri and transmitted discrete multitone symbol Si respectively,
- inverting the transfer matrices H(fj) to produce inverted matrices H−1(fj), which are used as precompensating matrices at tones fj.
A modem comprising a far-end crosstalk canceling circuit, said far-end crosstalk canceling circuit comprising a precompensation circuit multiplying, before transmission, a vector S=(Si), i=1 to n, by a precompensation matrix such that the matrix product H*M is diagonal, H being a transfer matrix of a plurality of transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the digital transmission symbols Ri respectively received by the modem.
A modem comprising a far-end crosstalk canceling circuit, said far-end crosstalk canceling circuit comprising a precompensation circuit multiplying, before transmission, a vector S=(Si), i=1 to n, by a precompensation matrix such that the matrix product H*M is diagonal, H being a transfer matrix of a plurality of transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the digital transmission symbols Ri respectively received by a modem;
- wherein the far-end crosstalk canceling circuit further comprises:
- a storage circuit storing transfer matrices of the plurality of transmission channels at tones being defined by R(fj)=H(fj)*S(fj), where R(fj) is the vector R(fj) (Ri(fj)) i=1 to n and S(fj) is the vector S(fj)=(Si(fj)), i=1 to n, Ri(fj) and Si(fj) being the components at tone fj of the received discrete multitone symbol Ri and transmitted discrete multitone symbol Si respectively;
- and
- an inversion circuit sequentially inverting said transfer matrices H(fj) and supplying the precompensation circuit with the inverted matrices H−1(fj), the precompensation circuit sequentially calculating the products H−1(fj)*S(fj).
A data transmission system comprising a plurality of line transmission modems transmitting discrete multitone symbols Si to corresponding network termination modems over n transmission channels, including means for precompensating for far-end crosstalk;
- wherein the means for precompensating for far-end crosstalk further comprise means for multiplying, before transmission, a vector S=(Si), i=1 to n, by a precompensation matrix M such that the diagonal of the product equals H*M, where H is a transfer matrix of the plurality of transmission channels defined by R=H*S, where R=(Ri), i=1 to n, is the vector of the digital transmission symbols Ri respectively received by the modems.
Dependencies are inferred from the claim text.