WO2012109853A1 - 通过预编码消除远端串音的方法和装置 - Google Patents

通过预编码消除远端串音的方法和装置 Download PDF

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Publication number
WO2012109853A1
WO2012109853A1 PCT/CN2011/077780 CN2011077780W WO2012109853A1 WO 2012109853 A1 WO2012109853 A1 WO 2012109853A1 CN 2011077780 W CN2011077780 W CN 2011077780W WO 2012109853 A1 WO2012109853 A1 WO 2012109853A1
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matrix
precoding
strong
channel
ndd
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PCT/CN2011/077780
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English (en)
French (fr)
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涂建平
卫东
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华为技术有限公司
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Priority to CN2011800010883A priority Critical patent/CN102318299B/zh
Priority to PCT/CN2011/077780 priority patent/WO2012109853A1/zh
Publication of WO2012109853A1 publication Critical patent/WO2012109853A1/zh

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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B3/00Line transmission systems
    • H04B3/02Details
    • H04B3/32Reducing cross-talk, e.g. by compensating
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M3/00Automatic or semi-automatic exchanges
    • H04M3/22Arrangements for supervision, monitoring or testing
    • H04M3/26Arrangements for supervision, monitoring or testing with means for applying test signals or for measuring
    • H04M3/34Testing for cross-talk

Definitions

  • the present invention relates to the field of communications technologies, and in particular, to a method and apparatus for eliminating far-end crosstalk by precoding.
  • Digital Subscriber Line is a high-speed data transmission technology that uses telephone twisted pair as the transmission medium.
  • xDSL is a general term for various types of DSL.
  • the Digital Subscriber Line Access Multiplexer (DSLAM) is a central office device for various DSL systems and is used to provide multi-channel xDSL access. Due to electromagnetic induction, interference occurs between multiple signals accessed by the DSLAM, called crosstalk, including Far-end Crosstalk (FEXT), and severe far-end crosstalk can significantly reduce the channel. Rate, affecting channel transmission performance.
  • the industry has proposed a vectored DSL technology that cancels far-end crosstalk by combining transceiving at the DSLAM end.
  • the signal transmitted on each pair in the cable bundle is a vector signal that, in addition to its own signal component, includes signal components associated with signals on other pairs.
  • the vectorized DSL technique introduces a precoder to precode the transmitted signal X to eliminate far-end crosstalk.
  • the precoding matrix be P
  • the transmitted signal is Px
  • the far-end crosstalk can be eliminated.
  • H- 1 is the inverse matrix of H
  • Hd is the diagonal matrix of H, that is, the element other than the main diagonal in H is zeroed, leaving only the matrix of the elements of the main diagonal.
  • the precoded signal transmission power may increase beyond the power mask (PSDMASK) limit.
  • PSDMASK power mask
  • the normalization factor is ⁇ , then the normalized precoding matrix is: ⁇ d
  • the normalization process can make the signal transmission power meet the requirements of PSDMASK, but there is a problem that if a channel is subjected to more crosstalk than other channels, the normalization factor needs to be 4 inches, after normalization, The transmission power spectrum and signal-to-noise ratio (SNR) of other channels with less crosstalk are significantly reduced, resulting in a large loss of channel transmission performance.
  • SNR signal-to-noise ratio
  • the embodiment of the invention provides a method for eliminating far-end crosstalk by precoding, which can reduce the loss of channel transmission performance after normalization.
  • Embodiments of the present invention also provide corresponding devices.
  • a method for eliminating far-end crosstalk by precoding includes:
  • the partitioned channel matrix includes a plurality of sub-matrices including a strong diagonal dominant matrix and a non-strong diagonal dominant matrix; precoding the transmitted signal, and The transmission signal on the channel represented by the non-strong diagonally dominant matrix is spectrally controlled so that the pre-coded signal transmission power does not exceed the power mask limit.
  • a device for eliminating far-end crosstalk by precoding includes:
  • a blocking unit configured to block the channel matrix, wherein the partitioned channel matrix comprises a plurality of sub-matrices, wherein the sub-matrices comprise a strong diagonal dominant matrix and a non-strong diagonal dominant matrix;
  • a precoding unit configured to precode the transmitted signal
  • the frequency control unit is configured to perform spectrum control on the transmission signal on the channel represented by the non-strong diagonally dominant matrix, so that the pre-coded signal transmission power does not exceed the power language mask limit.
  • the channel matrix is divided, so that the sub-matrix after the block includes a strong diagonal dominant matrix and a non-strong diagonal dominant matrix, and only needs to be non-strong when performing precoding and frequency speech control.
  • the diagonally dominant channel is frequency-controlled without having to perform spectrum control on all channels, so that the signal transmission power does not exceed the power mask limit, and thus the transmission power spectrum and signal of the channel with strong diagonally dominant channels
  • the noise ratio is not reduced by the influence of the frequency control, and the loss of channel transmission performance is reduced.
  • the precoding matrix of the entire channel matrix can be obtained by respectively solving the precoding matrix of the sub-matrix with smaller dimensions, thereby reducing the complexity of the precoding matrix and reducing the calculation amount.
  • FIG. 1 is a flowchart of a method for canceling far-end crosstalk by precoding according to an embodiment of the present invention
  • FIG. 2 is a logical structural diagram of a precoding apparatus according to an embodiment of the present invention. detailed description
  • Embodiments of the present invention provide a method for eliminating far-end crosstalk by precoding.
  • a part of a channel matrix has a strong diagonal dominant characteristic, and another part has a non-strong diagonal dominant characteristic. Therefore, it is not necessary to perform spectrum control on all channels, and it is only necessary to perform frequency control on a channel having non-strong diagonal dominant characteristics, which can reduce the loss of channel transmission performance after frequency control.
  • Embodiments of the invention also provide corresponding apparatus. The details will be described in detail below with reference to the accompanying drawings. Referring to FIG. 1 , an embodiment of the present invention provides a method for eliminating far-end crosstalk by precoding, including:
  • Block the channel matrix, and the channel matrix after the block includes a plurality of sub-matrices, where the sub-matrices include a strong diagonal dominant matrix and a non-strong diagonal dominant matrix.
  • the channel matrix of the cable bundle can be written as follows:
  • the channel matrix H is a matrix of M x M, where each row represents a channel.
  • the element h u in the channel matrix H that is, the diagonal line from the element to h MM is called the main diagonal, and the element on the main diagonal is called the main diagonal element, not on the main diagonal. Elements are called non-primary diagonal elements.
  • the channel matrix H can be derived by a conventional channel estimation algorithm.
  • the signal component transmitted on one channel is much larger than the crosstalk of other channels to the channel.
  • the modulus of the main diagonal element 1 ⁇ 2 of a row of the matrix is much larger than the non-main diagonal of the row.
  • the sum of the modulo of the element 1 ⁇ 2, the channel represented by the row at this time can be referred to as a strong diagonal dominant channel.
  • crosstalk is enhanced between high frequency bands such as 30 MHz to 100 MHz or extended channels, so that the crosstalk transmitted on a certain channel is larger than the signal component transmitted on the channel.
  • the modulus of the main diagonal element 1 ⁇ 2 of a row of the matrix is smaller than the sum of the modules of the non-primary diagonal elements of the row.
  • the channel represented by the row may be referred to as a non-strong diagonal.
  • Excellent channel If each row in the channel matrix is a strong diagonally dominant channel, the channel matrix can be referred to as a strong diagonally dominant matrix. If there is one or several non-strong diagonally dominant channels in the channel matrix, the channel matrix may be referred to as a non-strong diagonally dominant matrix.
  • the ideal precoding matrix P H - the pre-coded signal transmission power is very close to the original transmission power and does not exceed the power spectrum mask (PSDMASK) limit.
  • the signal transmission power is amplified after precoding with an ideal precoding matrix, and normalization is required to ensure that the power mask is not exceeded.
  • the embodiment of the present invention is based on the above analysis, and considering that even in a non-strong diagonally dominant matrix, some channels may be strong diagonally dominant channels, in order to utilize the excellent characteristics of the strong diagonally dominant matrix, this embodiment
  • the partial sub-matrix after the block can maintain strong diagonal dominant characteristics.
  • the channel matrix H can be divided into four blocks to make the channel matrix after the block
  • H DD is a strong diagonal dominant matrix
  • HNDD is a non-strong diagonal dominant ⁇ matrix
  • the channel matrix H can be divided into four blocks, expressed as:
  • H DD is a strong diagonal dominant matrix
  • H NDD non-strong diagonal dominant matrix
  • H DD is a strong diagonally dominant matrix
  • the modulus of the submatrix composed of non-primary diagonal elements of the same row is much smaller than that of the submatrix H DD ; due to the symmetry of the crosstalk coupling, the modulus of the other submatrix A ⁇ A module that is much smaller than the submatrix H DD .
  • the transmission signal X is also divided according to the channel matrix after the block, and the c after the block:
  • the transmission signal X is a matrix of M x 1. If H performs row swapping, starting from the first row to the left L column of the Lth row, forming the submatrix H DD , then correspondingly, the upper L row in the signal X is used as a submatrix X DD , and the following part is used as another Submatrix
  • the step may be: sending a signal; C: performing precoding, where
  • H DD represents the transmitted signal of the strong diagonally dominant channel
  • 3 ⁇ 4 ⁇ is the transmitted signal of the non-strong diagonally dominant channel represented by ⁇
  • P H 4 H D
  • HP' This operation can be called block diagonalization, that is, by right multiplying a matrix to make a block
  • the two sub-matrices on the main diagonal of the channel matrix 0 after 0 ⁇ are zero. Then, the precoding matrix P DP of the submatrix H DD and the precoding matrix PNDP of the H NDD are respectively calculated, thereby obtaining the precoding of the channel matrix H.
  • the computational complexity can be greatly reduced compared to the precoding matrix HP directly calculating H, and the amount of computation can be greatly reduced.
  • the transmission signal X is subjected to spectrum control to control the transmission power thereof, only the signal XNDD corresponding to each channel indicated by the non-strong diagonally dominant matrix H NDD may be spectrally controlled, so that the transmission power of the spectrum controlled signal x NDD does not exceed limit the power spectrum mask, without regard to a strong diagonal dominant matrix H of the respective channels corresponding to the signal DD represents x DD. This is because the submatrix H DD is a strong diagonally dominant matrix.
  • the transmit power of the signal x DD of the partial channel precoded by the ideal precoding matrix is very close to the original transmit power and does not exceed the power mask. (PSDMASK) restrictions.
  • PSDMASK power mask restrictions.
  • the embodiment of the present invention does not limit the spectrum control on the channel represented by the strong diagonal dominant channel to further ensure that the signal transmission power does not exceed the power mask limit.
  • the method for eliminating far-end crosstalk by precoding divides the channel matrix into blocks, so that the sub-matrix of the channel matrix after the block includes a strong diagonal dominant matrix and a non-strong diagonal dominant Matrix, when performing precoding and frequency control, only need to perform spectrum control on a channel that is not strong diagonally dominant, and without frequency control on all channels, the signal transmission power can not exceed the power mask. Restricted, in this way, the transmit power spectrum and signal-to-noise ratio of the channel dominated by the strong diagonal are not affected by the frequency control. Reduced, the loss of channel transmission performance is reduced.
  • the precoding matrix of the entire channel matrix can be obtained by respectively solving the precoding matrix of the sub-matrix with smaller dimensions, thereby reducing the complexity of the precoding matrix and reducing the calculation amount.
  • the localized normalization method may be used to perform frequency control on the transmitted signal.
  • the post-blocking channel matrix can be expressed as ⁇ ZJ ZJ
  • the transmitted signal can be expressed as
  • H DD is a strong diagonal dominant matrix
  • H NDD is a non-strong diagonal dominant matrix
  • x DD is Strong diagonal dominant matrix of each channel corresponding to a channel signal represented by H DD, a signal of the respective channel x NDD non strong diagonal dominant matrix H NDD corresponding representation.
  • H ⁇ -1 is the inverse matrix of the submatrix H DD
  • ⁇ ( ⁇ ⁇ ) is the diagonal matrix of the submatrices H DD
  • ⁇ ( ⁇ is the diagonal matrix of the sub-matrix H NDD .
  • the local normalization coefficient P NDD is calculated to locally localize the signal x NDD corresponding to each channel represented by the non-strong diagonally dominant matrix H NDD
  • ⁇ ⁇ of the precoding matrix PNDD Precoded and partially normalized
  • the transmitted signal is: ⁇ ⁇
  • the signal y received by the receiver is:
  • step 120 in this embodiment may specifically be: al, calculate a matrix ⁇ ', make HP', and calculate a precoding matrix of H DD P : DP
  • P NDD is the maximum value of the Euclidean norm of the row vector of each row in the PNDD
  • dl precoding with the local normalization coefficient ⁇ NDD
  • the locally normalized transmitted signal is P ⁇ 1
  • a constant can be added to make the localized normalization.
  • Sending a signal of 1 ⁇ can be an empirical value summed up from daily experience.
  • the method provided in this embodiment obtains the precoding matrix of the entire channel matrix by separately calculating the precoding matrix of each submatrix, which reduces the complexity of the precoding matrix and reduces the calculation amount;
  • the precoding matrix of the non-strong diagonally dominant matrix calculates the local normalized constant to perform local normalization on the non-strong diagonally dominant channel, avoiding global normalization of all channels, compared to the prior art.
  • the technique improves the signal-to-noise ratio of the strong diagonally dominant channel and reduces the loss of channel transmission performance.
  • the channel matrix can be represented as N DD, NDD.
  • the signal y that the receiver can receive is as follows:
  • the frequency of the transmission signal of the non-strong diagonally dominant channel is optimized to achieve the purpose of frequency control, and the signal transmission power is controlled within the limit of the power mask.
  • the pre-coded signal can be frequency-optimized by solving the following formula: max
  • OT represents the bit rate of the bit carried on the nth subcarrier of the non-diagonally dominant channel
  • max ⁇ ⁇ represents the bit rate of all subcarriers of all non-strong diagonally dominant channels.
  • E represents the power spectrum energy transmitted by the nth subcarrier of any non-strong diagonally dominant channel; represents the sum of the power spectrum energies of all subcarriers transmitted on any non-strong diagonally dominant channel
  • 0 is a commonly used symbol of mathematics, indicating that the following conditions are satisfied; a power mask limit of the nth subcarrier on a non-strong diagonally dominant channel is represented; V) / 5 represents an arbitrary sub-arbitrarily on a non-strong diagonally dominant channel.
  • Carrier; represents the total power limit of a non-strong diagonally dominant channel, S fresh, DP represents any non-strong diagonally dominant channel.
  • the power of the nth subcarrier of a non-strong diagonally dominant channel represented by the non-strong diagonally dominant matrix H ⁇ after precoding is E
  • n P 4 P NDP X N n DP
  • represents the nth subcarrier.
  • step 120 in this embodiment may specifically be: a2, calculating a matrix, and calculating precoding of H DD
  • the transmitted signal of the channel represented by the non-strong diagonally dominant matrix H ⁇ is ⁇ ⁇ ⁇ ⁇ 3 ⁇ , C2.
  • the method may include: first, according to the calculated power E among them
  • the method provided in this embodiment obtains the ideal precoding matrix of the entire channel matrix by separately calculating the precoding matrix of each submatrix, reduces the complexity of the precoding matrix, reduces the calculation amount, and performs the transmission signal.
  • precoding local spectrum optimization is performed on the channel represented by the non-strong diagonally dominant matrix H ⁇ D, which avoids frequency-optimization of all channels, and improves the signal-to-noise of the strong diagonally dominant channel compared with the prior art. Compared, the loss of channel transmission performance is reduced.
  • the signal transmitting end that is, the DSLAM and the signal receiving end, both have the capability of precoding and joint cancellation, and the precoding is performed at the transmitting end, and the joint cancellation is performed at the receiving end so that the transmitting power of the signal is not Exceeds the limit of the power mask.
  • HH send signal X can be expressed as c: can calculate a matrix corpse'
  • singular value decomposition can be performed on the non-strong diagonally dominant matrix H ⁇ D.
  • UAV U and V are both ⁇ matrices, ⁇ For the diagonal matrix.
  • H After / ⁇ - ⁇ and ⁇ : ⁇ ⁇ are used for inner precoding and joint cancellation processing on the non-strong diagonally dominant channel represented by H, H will be transformed into a diagonal matrix ⁇ , then New channel matrix
  • is a diagonal matrix and H ⁇ is a strong diagonally dominant matrix, it is also a strong diagonally dominant matrix. Therefore, after precoding the transmission signal X by using the precoding matrix, the transmission power of the signal X can be made not to exceed the limit of the power mask.
  • the distributed water injection algorithm controls the transmission power. Just fine. In this embodiment, the power E can be precoded twice for each non-strong diagonally dominant channel.
  • n denotes subcarriers, using a distributed water injection algorithm for spectrum optimization
  • b represents the bit rate carried on the nth subcarrier of the non-diagonally dominant channel: Max ; ⁇ denotes a maximum of the bit rates of all subcarriers of the non-strong diagonally dominant channel; according to the Shannon capacity formula,
  • represents the power spectrum energy transmitted by the nth subcarrier of any non-strong diagonally dominant channel; Indicates the sum of the power spectrum energies of all subcarriers transmitted on any non-strong diagonally dominant channel 0 is a commonly used symbol of mathematics, indicating that the following conditions are satisfied; a power mask limit of the nth subcarrier on a non-strong diagonally dominant channel is represented; V « indicates any subcarrier on the non-strong diagonally dominant channel; ⁇ represents the total power limit of a non-strong diagonally dominant channel.
  • step 120 in this embodiment may specifically be:
  • the distributed water injection algorithm is used to optimize the frequency of the channel represented by the non-strong diagonally dominant matrix H ⁇ D, so that the signal transmission power on each channel does not exceed the power mask limit.
  • the method provided in this embodiment divides the channel matrix H into blocks, performs SVD decomposition on the non-strong diagonal matrix in the block H, and obtains a local precoding matrix and a joint cancellation matrix according to the decomposition result.
  • the strong diagonal matrix performs local precoding and joint cancellation, and turns it into a diagonal matrix, thereby obtaining a new strong diagonally dominant channel matrix and then precoding with an ideal precoding matrix pair, which can make the precoded signal
  • the transmit power does not exceed the limit of the power mask.
  • the distributed water injection algorithm can also be used to optimize the frequency of the non-strong diagonally dominant channel or all channels, so that the transmission power of each channel does not exceed the power mask limit, and the respective line rates are the largest.
  • the SVD decomposition since the SVD decomposition is adopted, the complexity of solving the precoding matrix and the frequency speech optimization algorithm can be greatly reduced, and the speed of spectrum optimization is improved. Referring to FIG.
  • an embodiment of the present invention further provides a precoding apparatus, which is used in a DSLAM, and includes: a blocking unit 210, configured to block a channel matrix, where the channel matrix after the partition includes a plurality of sub-matrices, The sub-matrix comprises a strong diagonally dominant matrix and a non-strong diagonally dominant matrix; a precoding unit 220 is configured to precode the transmitted signal; and a spectrum control unit 230 is configured to use the non-strong diagonally dominant matrix
  • the transmitted signal on the indicated channel is frequency-controlled so that the pre-coded signal transmission power does not exceed the power mask limit.
  • the blocking unit 210 may be configured to block the channel matrix H so that n DD n DD 'NDD
  • the precoding unit 220 can be used to precode the transmitted signal; c X
  • the spectral control unit 230 can be used to control XNDD spectrum, the pre- Encoded letter The number of the transmission power does not exceed the limit of the power mask.
  • the precoding unit 220 may be specifically configured to calculate a matrix P '
  • Precoding the transmitted signal x with a precoding matrix ⁇ ⁇ '.
  • the spectrum control unit 230 is configured to calculate a local normalization coefficient ⁇ NDD according to P NDD , P NDD is a maximum value of a Euclidean norm of a row vector of each row in P NDD ; adopting local normalization
  • the coefficient ⁇ NDD locally localizes the precoded transmission signal X, and the locally normalized transmission signal is
  • the precoding unit 220 may be specifically configured to calculate a matrix P '
  • Precoding the transmitted signal x with a precoding matrix ⁇ ⁇ '.
  • the spectrum control unit 230 is configured to calculate a local normalization coefficient ⁇ NDD according to P NDD , P NDD is a maximum value of a Euclidean norm of a row vector of each row in P NDD ; adopting local normalization
  • the coefficient ⁇ NDD locally localizes the precoded transmission signal x, and the locally normalized transmission signal is
  • the precoding unit 220 may be specifically configured to calculate a matrix
  • HP and HP 'and computes the precoding matrix of the H DD precoding matrix P DP and HNDD P NDP ;
  • the transmission signal of the channel represented by the dominant matrix ⁇ is P 4 P NDP x
  • the spectrum control unit 230 is configured to transmit signals according to Frequency-optimized for the channel represented by the non-strong diagonally dominant matrix H.
  • the signal x is precoded, and the precoded signal is P X will be calculated.
  • the channel represented by H performs spectrum optimization.
  • the channel matrix is divided by the precoding apparatus, so that the submatrix of the channel matrix after the block includes a strong diagonal dominant matrix and a non-strong diagonal dominant matrix, and precoding and spectrum control are performed.
  • the transmission power spectrum and signal-to-noise ratio of the channel are not affected by the frequency control, and the channel transmission performance is The loss is reduced.
  • the precoding matrix of the entire channel matrix can be obtained by respectively solving the precoding matrix of the sub-matrix with smaller dimensions, thereby reducing the complexity of the precoding matrix and reducing the calculation amount.
  • the storage medium may include: a read only memory, a random read memory, a magnetic disk or an optical disk, and the like.

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Abstract

本发明公开了一种通过预编码消除远端串音的方法,包括:对信道矩阵进行分块,分块后的信道矩阵包含若干个子矩阵,所述子矩阵中包括强对角占优矩阵和非强对角占优矩阵;对发送信号进行预编码,并对所述非强对角占优矩阵表示的信道上的发送信号进行频谱控制,使预编码后的信号发送功率不超过功率谱掩码的限制。本发明实施例还提供相应的装置。本发明技术方案,由于只需要对非强对角占优的信道进行频谱控制,不必对全部信道进行频谱控制,可以减少因频谱控制造成的信道传输性能的损失;由于可以通过分别求解维度较小的子矩阵的预编码矩阵获得整个信道矩阵的预编码矩阵,可以降低求预编码矩阵的复杂度,减小计算量。

Description

通过预编码消除远端串音的方法和装置
技术领域
本发明涉及通信技术领域,具体涉及一种通过预编码消除远端串音的方法 和装置。
背景技术
数字用户线路 ( Digital Subscriber Line, DSL )是一种以电话双绞线为传 输介质的高速数据传输技术。 xDSL是各种类型 DSL的总称。数字用户线路接 入复用器( Digital Subscriber Line Access Multiplexer, DSLAM )是各种 DSL 系统的局端设备, 用于提供多路 xDSL接入。 由于电磁感应, DSLAM接入的 多路信号之间会产生干扰, 称为串音( Crosstalk ), 其中包括远端串音( Far-end Crosstalk, FEXT ),严重的远端串音会显著降低信道速率,影响信道传输性能。
业界提出了一种向量化( Vectored ) DSL技术, 通过在 DSLAM端进行联 合收发来抵消远端串音。通常, 电缆束中的每条线对上发送的信号都是向量信 号, 除了本身的信号分量以外, 还包括与其他线对上的信号相关的信号分量。 可以用信道矩阵 H表示各线对之间的传递函数以及对应的串音传递函数,用 X 表示信道输入向量, y表示信道输出向量, 用 n表示噪声向量。 则信道传输方 程可以表示为: y=Hx+n。 其中, 如果信道个数为整数 M, 则 H是一个 M x M 的矩阵, x、 y以及 n都是 M 1的矩阵。
对于下行信道, 向量化 DSL技术引入一个预编码器对发送信号 X进行预 编码来消除远端串音。设预编码矩阵为 P, 则发送的信号为 Px, 那么接收端接 收的信号y=HPx+n。 计算一个合适的 P, 使 HP成为一个对角矩阵, 则远端串 音就可以消除了。 通常, 理想的预编码矩阵
Figure imgf000003_0001
其中, H-1是 H的逆 矩阵; Hd是 H的对角矩阵, 即, 将 H中的主对角线以外的元素置零, 只保留 主对角线的元素的矩阵。
预编码后的信号发送功率可能会增大, 超过功率语掩码(PSDMASK )的 限制。 为保证信号发送功率满足 PSDMASK的要求, 有必要进行归一化处理,
1
_ __ H 1 H
殳归一化因子为 β , 则归一化后的预编码矩阵为: β d 归一化处理可以使信号发送功率满足 PSDMASK的要求, 但是存在如下 问题:如果某一个信道受到的串扰比其它信道大 4艮多,归一化因子就需要 4艮大, 归一化处理后, 其它受到串扰较小的信道的发射功率谱及信噪比(SNR )会明 显降低, 从而使得信道传输性能损失较大。
发明内容
本发明实施例提供一种通过预编码消除远端串音的方法,可以减小归一化 处理后信道传输性能的损失。 本发明实施例还提供相应的装置。
一种通过预编码消除远端串音的方法, 包括:
对信道矩阵进行分块, 分块后的信道矩阵包含若干个子矩阵, 所述子矩阵 中包括强对角占优矩阵和非强对角占优矩阵; 对发送信号进行预编码,并对所述非强对角占优矩阵表示的信道上的发送 信号进行频谱控制, 使预编码后的信号发送功率不超过功率语掩码的限制。
一种通过预编码消除远端串音的装置, 包括:
分块单元, 用于对信道矩阵进行分块, 分块后的信道矩阵包含若干个子矩 阵, 所述子矩阵中包括强对角占优矩阵和非强对角占优矩阵;
预编码单元, 用于对发送信号进行预编码;
频语控制单元,用于对所述非强对角占优矩阵表示的信道上的发送信号进 行频谱控制, 使预编码后的信号发送功率不超过功率语掩码的限制。
本发明实施例方法,将信道矩阵分块,使分块后的子矩阵包括强对角占优 矩阵和非强对角占优矩阵,在进行预编码和频语控制时, 只需要对非强对角占 优的信道进行频语控制, 而不必对全部信道进行频谱控制, 就可使信号发送功 率不超过功率语掩码的限制,从而, 强对角占优的信道的发射功率谱及信噪比 不会受频语控制的影响而降低, 信道传输性能的损失得以减少。 并且, 将信道 矩阵分块后,可以通过分别求解维度较小的子矩阵的预编码矩阵获得整个信道 矩阵的预编码矩阵, 从而降低求预编码矩阵的复杂度, 减小计算量。
附图说明
图 1是本发明实施例提供的通过预编码消除远端串音的方法的流程图; 图 2是本发明实施例提供的预编码装置的逻辑结构图。 具体实施方式
本发明实施例提供一种通过预编码消除远端串音的方法,通过将信道矩阵 分块,使信道矩阵中的一部分具有强对角占优特性, 另一部分具有非强对角占 优特性,从而不必对全部信道进行频谱控制, 只需对其中具有非强对角占优特 性的信道进行频语控制, 可以减少信道传输性能在频语控制后的损失。本发明 实施例还提供相应的装置。 以下结合附图分别进行详细说明。 请参考图 1 , 本发明实施例提供一种通过预编码消除远端串音的方法, 包 括:
110、 对信道矩阵进行分块, 分块后的信道矩阵包含若干个子矩阵, 所述 子矩阵中包括强对角占优矩阵和非强对角占优矩阵。 假设电缆束中包含 M条线对, 每条线对作为一个信道, 则该电缆束的信 道矩阵可以写为如下形式:
H =
Figure imgf000005_0001
其中, ½表示线对 i的传递函数, 表示线对 j对线对 i的串音传递函数; i和 j都是不大于 M的自然数, 分别用于表示第 i条线对和第 j条线对。 信道 矩阵 H是一个 M x M的矩阵, 其中的每一行表示一个信道。 本文中, 将信道 矩阵 H中的元素 hu即元素 到 hMM所在的对角线称为主对角线, 主对角线上 的元素称为主对角元素, 不在主对角线上的元素称为非主对角元素。可以通过 常规的信道估计算法得出信道矩阵 H。
一般的, 一个信道上传递的信号分量远大于其它信道对该信道的串音,表 现在信道矩阵中则为, 矩阵某一行的主对角元素 ½的模远大于该行的各个非 主对角元素 ½的模的和, 此时该行表示的信道可以称为强对角占优信道。 但 是, 随着技术的发展以及信道的扩展, 在高频例如 30MHz至 100MHz的频带 或者扩展的信道之间, 串音会增强,使得某个信道上传递的串音大于该信道上 传递的信号分量, 表现在信道矩阵中则为, 矩阵某一行的主对角元素 ½的模 小于该行的各个非主对角元素 的模的和, 此时该行表示的信道可以称为非 强对角占优信道。如果信道矩阵中每一行都是强对角占优信道, 则该信道矩阵 可以称为强对角占优矩阵。 如果信道矩阵中有一行或几行为非强对角占优信 道, 该信道矩阵可以称为非强对角占优矩阵。
如果信道矩阵 H为强对角占优矩阵,采用理想的预编码矩阵 P=H— 预编 码后的信号发送功率非常接近原始的发送功率, 不会超过功率谱掩码 ( PSDMASK )的限制。 但是在信道矩阵 H为非强对角占优矩阵时, 使用理想 的预编码矩阵进行预编码后信号发送功率会放大,需要进行归一化处理以保证 不会超过功率语掩码的限制。
本发明实施例基于上述分析, 以及考虑到即便在非强对角占优矩阵中,仍 有部分信道可能是强对角占优信道, 为利用强对角占优矩阵的优异特性, 本实 施例中,通过对信道矩阵进行分块处理,使分块后的部分子矩阵可以保持强对 角占优特性。 一般的, 可以将信道矩阵 H 分为四块, 使分块后的信道矩阵
H ^ H D τ D ,NDD
H , 其中, HDD为强对角占优矩阵, HNDD为非强对角占优 ί 矩阵。 具体的分块方法如下:
判断信道矩阵的每一行是否为强对角占优信道;
如果某一行中主对角元素的模大于各个非对角元素的模之和,认为该信道 为强对角占优信道, 否则为非强对角占优信道。 进行行交换,将强对角占优信道的行交换到矩阵的上方,将非强对角占优 信道的行交换到矩阵的下方。 行交换后, 信道矩阵 H可以分为四块, 表示为: H
Figure imgf000007_0001
其中, 主对角线上形成两个子矩阵, 一个为强对角占优矩阵 HDD, 另一个 为非强对角占优矩阵 HNDD。 由于 HDD为强对角占优矩阵, 则相同行的非主对 角元素组成的子矩阵 的模远小于子矩阵 HDD的模;由于串扰耦合的对称 性, 另一子矩阵 A^ 的模远小于子矩阵 HDD的模。 还根据分块后的信道矩阵将发送信号 X进行分块, 分块后的 c :
Figure imgf000007_0002
中, ¾。是 0表示的强对角占优信道的发送信号, ½DD是 HNDD表示的非强对角 占优信道的发送信号。 在信道个数为 M时, 发送信号 X是一个 M x 1的矩阵。 如 果 H进行行交换后, 从第一行开始到第 L行的左边 L列, 形成子矩阵 HDD, 则相 应的, 信号 X中的上面 L行作为一个子矩阵 XDD, 以下部分作为另一个子矩阵
X NDD c
在其它实施方式中,分块后也可以有 H ,相应的使分块
Figure imgf000007_0003
120、 对发送信号进行预编码, 并对非强对角占优矩阵表示的信道上的发 送信号进行频语控制, 使预编码后的信号发送功率不超过功率语掩码的限制。
具体的, 本步骤可以是: 对发送信号; C : 进行预编码, 其中,
HDD表示的强对角占优信道的发送信号, ¾∞表示的非强对角占优信道 的发送信号, 并对 xNDD进行频谱控制, 使预编码后的信号发送功率不超过功率 谱掩码的限制。 本实施例可以采用常规方法例如采用理想的预编码矩阵 P=H4HD对发送信 号 X进行预编码。 根据工程矩阵理论, 对于任一个矩阵, 必然存在另一个矩阵, 这两个矩阵相乘后变成块对角化矩阵。 于是, 可以计算出一个矩阵 Ρ ' , 使
HP' 该操作可以称为块对角化, 即, 通过右乘一个矩阵使分块
0 Η 后的信道矩阵 Η的不在主对角线上的两个子矩阵为零。 然后, 分别计算子矩阵 HDD的预编码矩阵 PDP和 HNDD的预编码矩阵 PNDP, 从而得到信道矩阵 H的预编码
0
由于分块后得到的子矩阵的维度仅为原信道矩阵的
0 Rn 一 半, 在计算预编码矩阵 PDI ^PNDP, 相对于直接计算 H的预编码矩阵 HP, 计算 复杂度可以大大降低, 计算量可以大大减小。 对发送信号 X进行频谱控制以便控制其发送功率时, 可以只对非强对角占 优矩阵 HNDD表示的各个信道对应的信号 XNDD进行频谱控制,使频谱控制后信号 xNDD的发送功率不超过功率语掩码的限制, 而不必考虑强对角占优矩阵 HDD表 示的各个信道对应的信号 xDD。 这是因为, 子矩阵 HDD为强对角占优矩阵, 采用 理想的预编码矩阵预编码后的该部分信道的信号 xDD的发送功率非常接近原始 的发送功率, 不会超过功率语掩码(PSDMASK ) 的限制。 从而, 只需对 xNDD 进行频语控制, 就可以整个信号 X的发送功率不超过功率语掩码的限制。
当然, 本发明实施例也不限制对强对角占优信道表示的信道进行频谱控 制, 以进一步保证信号发送功率不超过功率语掩码的限制。
综上, 本发明实施例提供的通过预编码消除远端串音的方法,将信道矩阵 分块, 使分块后的信道矩阵的子矩阵包括强对角占优矩阵和非强对角占优矩 阵,在进行预编码和频语控制时,只需要对非强对角占优的信道进行频谱控制, 而不必对全部信道进行频语控制,即可使信号发送功率不超过功率语掩码的限 制, 这样, 强对角占优的信道的发射功率谱和信噪比不会受频语控制的影响而 降低, 信道传输性能的损失得以减少。 并且, 将信道矩阵分块后, 可以通过分 别求解维度较小的子矩阵的预编码矩阵获得整个信道矩阵的预编码矩阵,从而 降低求预编码矩阵的复杂度, 减小计算量。 一种实施方式中, 可以采用局部归一化的方法对发送信号进行频语控制
HDD HL
分块后信道矩阵可以表示为 Η ZJ ZJ , 发送信号可以表示为
, 其中, HDD为强对角占优矩阵, HNDD为非强对角占优矩阵, xDD
Figure imgf000009_0001
强对角占优矩阵 HDD表示的各个信道对应的信号, xNDD对非强对角占优矩阵 HNDD表示的各个信道对应的信号。 预编码时, 可以计算出一个矩阵 Ρ ' , 使 ΗΡ ' · 然后, 分别计
0 ΗΛ 算子矩阵 HDD的预编码矩阵 PDI ^HNDD的预编码矩阵 Ρ N: DP-
Figure imgf000009_0002
^NDP _ ^NDD ' diClg (HwDD ) 其中, H^-1是子矩阵 HDD的逆矩阵, ·^(Ηββ)是子矩阵 HDD的对角矩阵; 是子矩阵 HNDD的逆矩阵, ·^(Η 是子矩阵 HNDD的对角矩阵。 然后, 计算局部归一化系数 P NDD, 用于对非强对角占优矩阵 HNDD表示的 各个信道对应的信号 xNDD进行局部归一化。 可以通过公式 = max||[P Lj 计算 A™, 该公式中 PM^LJ表示子矩阵 PNDD中第 n行的行向量的欧几里得范 数, β NDD则为子矩阵 PNDD中各行的行向量的欧几里得范数的最大值。 至此, 可以得出针对信道矩阵 H的理想的预编码矩阵为 Ρ = Ρ'.|
Figure imgf000009_0003
针对于其中预编码矩阵 PNDD的局部归一化系数 Αββ。 则经过预编码和局部归一 化处理的发送信号为: Ρ · , 而接收端收到的信号 y则为:
Figure imgf000010_0001
1 0
y= HP +η, 其中 η为噪声向量
β1
根据以上的分析推理, 则本实施例中步骤 120具体可以为: al、 计算一个矩阵 Ρ ' , 使 HP' , 并计算 HDD的预编码矩阵 P: DP
0 H 和 HNDD的预编码矩阵 PNDP;
0
bl、 采用预编码矩阵 Ρ = Ρ '. 对发送信号 X进行预编码;
0 Pm cl、 根据 PNDD计算局部归一化系数 β NDD, P NDD为 PNDD中各行的行向量的 欧几里得范数的最大值; dl、 采用局部归一化系数 β NDD对预编码后的发送信号 X进行局部归一化,
1 0
局部归一化后的发送信号为 P · 1
0 其中,为了进一步保证进行预编码和局部归一化的信号发送功率不超过功 率语掩码的限制, 可以在 基础上增加一个常量 使局部归一化后的发
1 0
送信号为 1 Δ 可以是由日常经验总结得到的经验值
0
β腸 β— 综上,本实施例提供的方法通过分别计算各个子矩阵的预编码矩阵来获得 整个信道矩阵的预编码矩阵, 降低了求预编码矩阵的复杂度, 减小了计算量; 根据非强对角占优矩阵的预编码矩阵计算出局部归一化常量进行对非强对角 占优信道进行局部归一化,避免了对所有信道进行全局归一化,相对于现有技 术提升了强对角占优信道的信噪比, 减小了信道传输性能的损失。 另一种实施方式中, 可以采用频语优化的方法对发送信号进行频语控制 分块后, 信道矩阵可以表示为 N DD,NDD
H , 发送信号可以表示
H H
Figure imgf000011_0001
Ρ 则进行块预编码后, 接收端可以收到的信号 y如下所示:
Figure imgf000011_0002
= HP '
Figure imgf000011_0005
Figure imgf000011_0003
+n
Figure imgf000011_0006
本实施例中,通过对非强对角占优信道的发送信号进行频语优化, 实现频 语控制的目的, 将信号发送功率控制在功率语掩码的限制以内。
可以通过求解以下公式对预编码后的信号进行频语优化: max
Figure imgf000011_0004
N
<SNDp NDP 该公式中, OT表示非对角占优信道的第 n个子载波上承载的比特 (bit ) 速率, max∑ βΡ表示使所有非强对角占优信道的所有子载波的 bit速率之和 Κ,Χ - Έ
最大化; 根据香农容量公式, 1 + - 其中 σ表示环境噪 σ. η表示子载波, h表示信道的传递函数。
E 表示任一非强对角占优信道的第 n个子载波发送的功率谱能量; 表示任一非强对角占优信道上所有子载波发送的功率谱能量之和
0是数学常用符号, 表示满足下列条件; 表示一非强对角占优信道 上第 η个子载波的功率语掩码限制; V )/5 表示任意的非强对角占优信道上任 意的子载波; 表示一非强对角占优信道的总功率限制, S鮮 , DP表示任 意的非强对角占优信道。 预编码后非强对角占优矩阵H■表示的一非强对角占优信道的第 n个子载 波的功率为 E
Figure imgf000012_0001
其中 n = P4PNDPXN n DP , η表示第 η个子载波。 将 xN n DP = ΡΛ^ ^;^代入上述公式( 1 ), 求解公式( 1 )表示的频谱优化问题, 根 据求解的结果进行频谱优化,即可实现将信号发送功率控制在功率语掩码的限 制以内。这是一种集中式的功率语控制方法,各用户信道之间的功率谱控制相 互制约。
根据以上的分析推理, 则本实施例中步骤 120具体可以为: a2、计算一个矩阵 , 并计算 HDD的预编码
Figure imgf000012_0003
矩阵 PDP和 HNDD的预编码矩阵 Pj
Figure imgf000012_0002
b2、 采用预编码矩阵 Ρ = Ρ' 对发送信号 X进行预编码, 则预编码
0 ,N, 后非强对角占优矩阵H■表示的信道的发送信号为 ΡΑΡΝ 3Χ, C2、根据发送信号 PAP xNnp对非强对角占优矩阵 H 表示的信道进行频谱 优化。 具体可以包括: 首先根据 计算功率 E
Figure imgf000013_0001
其中
XN"DP = P4PwnpX" , n表示子载波,再将 E
Figure imgf000013_0002
代入上述公式( 1 ),求解公式( 1 ) 表示的频语优化问题,根据求解的结果进行频语优化,将信号发送功率控制在 功率谱掩码限制以内。
综上,本实施例提供的方法通过分别计算各个子矩阵的预编码矩阵来获得 整个信道矩阵的理想预编码矩阵, 降低了求预编码矩阵的复杂度, 减小了计算 量;对发送信号进行预编码后,对非强对角占优矩阵 H^D表示的信道进行局部 的频谱优化,避免了对所有信道进行频语优化,相对于现有技术提升了强对角 占优信道的信噪比, 减小了信道传输性能的损失。 再一种实施方式中, 要求信号发送端即 DSLAM和信号接收端这双端同时 具有预编码和联合抵消的能力,通过在发送端进行预编码,在接收端进行联合 抵消使信号的发送功率不超过功率语掩码的限制。
联合抵消是指,在接收端接入一个串音抵消器, 以提供一个串音抵消矩阵 C , 如果信道传输方程为 y=Hx+n , 则加了串音抵消器后的收到的信号为 y=HCx+n, 当 HC为一个对角矩阵时, 远端串音得以消除。 根据上述实施例, 分块后, 信道矩阵 Η可以表示为 H
H H 发送信号 X可以表示为 c : 可以计算出一个矩阵尸' , 使
Figure imgf000013_0003
HP'
0 Η 本实施例中, 可以对非强对角占优矩阵 H^D进行奇异值分解 (singular value decomposition, SVD), SVD分解后有 = UAV" , 其中, U和 V均为酉 矩阵, Λ为对角矩阵。
SVD分解后, 可以先在发送端对非强对角占优信道进行内部预编码,使预 u^ pNDP = {vH yi =v 在接收端进行联合抵消, 使抵消矩阵 Cw^ ^tr ^t/ ; 由于 PNDP为酉矩阵, 发送信号 PNDP X的功率谱不会超过功率语掩码的限制。
采用 /^^^^-^^和^^:^^^ ^对 H 表示的非强对角占优信道进行 内预编码和联合抵消处理后, H,将化为对角矩阵 Λ, 则得到新的信道矩阵可
H DD,NDD
以表示为: H 。 然后, 可以求 的预编码矩阵 ^, 再对发送
H Λ 信号 X进行预编码。
由于 Λ为对角矩阵, H为强对角占优矩阵, 则 也为强对角占优矩阵。 从而, 采用预编码矩阵 对发送信号 X进行预编码后, 可以使信号 X的发送功率 不超过功率语掩码的限制。
然而, 由于局部的预编码酉矩阵 p
Figure imgf000014_0001
=v的每一行元素的模的能量 和保持不变, 那么信道之间预编码后的频谱优化关联性较小,但某些信道的功 率可能会超过功率语掩码的限制, 需要进行频语控制。采用 SVD分解方法生成 的预编码矩阵 Pm3p=G^)- =V是酉矩阵, 信号预编码以后具有总能量不变性, 各信道的功率语控制没有相关性, 进行分布式的注水算法控制发送功率即可。 本实施例中, 可以对每个非强对角占优信道两次预编码后的功率 E
0 0
x" =P" c", n表示子载波, 采用分布式的注水算法进行频谱优化, 对于
0 PL,
每个 NDP信道都有
Figure imgf000014_0002
·Ο≤Ε ≤ -0 ΛΝΟΡ ' (2)
Figure imgf000014_0003
<
Figure imgf000014_0004
该公式中, b 表示非对角占优信道的第 n个子载波上承载的 bit速率: max ; ^表示一个使非强对角占优信道的所有子载波的 bit速率之和最大化; 根据香农容量公式,
Figure imgf000015_0001
Ε 表示任一非强对角占优信道的第 n个子载波发送的功率谱能量;
Figure imgf000015_0003
表示任一非强对角占优信道上所有子载波发送的功率谱能量之和
Figure imgf000015_0004
0是数学常用符号, 表示满足下列条件; 表示一非强对角占优信道 上第 η个子载波的功率语掩码限制; V«表示该非强对角占优信道上任意的子载 波; ^^表示一非强对角占优信道的总功率限制。 通过求解上述公式 (2) 进行频谱优化, 可以使每个信道在不超过 PSDMASK的同时, 各自的线路速率最大。
根据以上的分析推理, 则本实施例中步骤 120具体可以为:
a3、 对非强对角占优矩阵 HNDD进行 SVD分解, 分解后的
Figure imgf000015_0002
ZUAV" ; b3、 计算预编码矩阵/^^^ - ^ , 联合抵消矩阵 <^= - ^t/", 并计 算强对角占优矩阵 的预编码矩阵 P;
H Λ 0 0
c3、 采用预编码矩阵 P 对发送信号 X进行预编码处理, 预编码
0 ,r
0 0
后的发送信号为 P X ,
0 P„r d3、 将联合抵消矩阵 :^/-1 =t/H发送给接收端设备;
e3、采用分布式注水算法对非强对角占优矩阵 H^D表示的信道进行频语优 化, 使每个信道上的信号发送功率不超过功率语掩码的限制。 综上, 本实施例提供的方法, 将信道矩阵 H分块, 对分块后 H中的非强对 角矩阵进行 SVD分解, 根据分解结果得到局部的预编码矩阵和联合抵消矩阵, 通过对非强对角矩阵进行局部预编码和联合抵消,将其化为对角矩阵,从而得 到新的强对角占优信道矩阵 再采用理想的预编码矩阵对 进行预编码, 可 以使预编码后的信号发送功率不超过功率语掩码的限制。还可以再采用分布式 注水算法对非强对角占优信道或者全部信道进行频语优化,以使每个信道的发 送功率在不超过功率语掩码限制的同时,各自的线路速率最大。本实施例由于 采用了 SVD分解, 可以大大降低求解预编码矩阵和频语优化算法的复杂度,提 高频谱优化的速度。 请参考图 2,本发明实施例还提供一种预编码装置,用在 DSLAM中, 包括: 分块单元 210, 用于对信道矩阵进行分块, 分块后的信道矩阵包含若干个 子矩阵, 所述子矩阵包括强对角占优矩阵和非强对角占优矩阵; 预编码单元 220, 用于对发送信号进行预编码; 频谱控制单元 230, 用于对所述非强对角占优矩阵表示的信道上的发送信 号进行频语控制, 使预编码后的信号发送功率不超过功率语掩码的限制。 具体的, 所述分块单元 210 , 可以用 于对信道矩阵 H进行分块, 使 n DD n DD'NDD
H ττ , 其中, HDD为强对角占优矩阵, HNDD为非强对角占优 ϋ ϋ ττ 矩阵; 所述预编码单元 220,可以用于对发送信号; c 进行预编码,其中, X
Figure imgf000016_0001
是 HDD表示的强对角占优信道的发送信号, ¾∞表示的非强对角占优信 道的发送信号; 所述频谱控制单元 230, 可以用于对 XNDD进行频谱控制, 使预编码后的信 号发送功率不超过功率语掩码的限制 一种实施方式中: 所述预编码单元 220 , 可以具体用 于计算一个矩阵 P ' , 使
HP' 并计算 HDD的预编码矩阵 PDP和 HNDD的预编码矩阵 PNDP; 采
0 H
0
用预编码矩阵 Ρ = Ρ'. 对发送信号 x进行预编码;
0 Pm 所述频谱控制单元 230, 用于根据 PNDD计算局部归一化系数 β NDD, P NDD 为 PNDD中各行的行向量的欧几里得范数的最大值; 采用局部归一化系数 β NDD 对预编码后的发送信号 X进行局部归一化, 局部归一化后的发送信号为
Figure imgf000017_0001
另一种实施方式中: 所述预编码单元 220 , 可以具体用 于计算一个矩阵 P ' , 使
HP' 并计算 HDD的预编码矩阵 PDP和 HNDD的预编码矩阵 PNDP; 采
0 H
0
用预编码矩阵 Ρ = Ρ'. 对发送信号 x进行预编码;
0 Pm 所述频谱控制单元 230, 用于根据 PNDD计算局部归一化系数 β NDD, P NDD 为 PNDD中各行的行向量的欧几里得范数的最大值; 采用局部归一化系数 β NDD 对预编码后的发送信号 x进行局部归一化, 局部归一化后的发送信号为
1 0
Ρ - 1 , 其中 Δ 为经验值。
0
β +Ν3 再一种实施方式中: 所述预编码单元 220 , 可以具体用于计算一个矩阵
Figure imgf000018_0001
HP ' 并计算 HDD的预编码矩阵 PDP和 HNDD的预编码矩阵 PNDP; 采
0 H 用预编码矩阵 POP 0
Ρ = Ρ'. 对发送信号 X进行预编码, 则预编码后非强对角
0 P„n, 占优矩阵 表示的信道的发送信号为 P4PNDPx 所述频谱控制单元 230 ,用于根据发送信号
Figure imgf000018_0002
对非强对角占优矩阵 H 表示的信道进行频语优化。 又一种实施方式中: 所述预编码单元 220 , 可以具体用于对非强对角占优矩阵 HNDD进行奇异值 SVD分解, ^ ^ UNDD = VAYH , 其中 U和 V均为酉矩阵, Λ为对角矩阵; 计 算预编码矩阵 P (^ =v , 联合抵消矩阵 = u-1 = UH , 并计算强对角占
Figure imgf000018_0003
0 0
发送信号 x进行预编码处理, 预编码后的发送信号为 P X 将计算出的
0 PARR 联合抵消矩阵 c = tr1 = t/H发送给接收端设备; 所述频谱控制单元 230 , 用于采用分布式注水算法对非强对角占优矩阵
H 表示的信道进行频谱优化。 本发明实施例提供的通过预编码装置, 将信道矩阵分块,使分块后的信道 矩阵的子矩阵包括强对角占优矩阵和非强对角占优矩阵,在进行预编码和频谱 控制时, 只需要对非强对角占优的信道进行频语控制, 而不必对全部信道进行 频语控制, 即可使信号发送功率不超过功率语掩码的限制, 这样, 强对角占优 的信道的发射功率谱和信噪比不会受频语控制的影响而降低,信道传输性能的 损失得以减少。 并且, 将信道矩阵分块后, 可以通过分别求解维度较小的子矩 阵的预编码矩阵获得整个信道矩阵的预编码矩阵,从而降低求预编码矩阵的复 杂度, 减小计算量。 本领域普通技术人员可以理解上述实施例的各种方法中的全部或部分步 骤是可以通过硬件完成,也可以通过程序来指令相关的硬件完成, 所说的程序 可以存储于一计算机可读存储介质中, 存储介质可以包括: 只读存储器、 随机 读取存储器、 磁盘或光盘等。
以上对本发明实施例所提供的通过预编码消除远端串音的方法以及相应 行了阐述, 以上实施例的说明只是用于帮助理解本发明的方法及其核心思想, 不应理解为对本发明的限制。

Claims

权 利 要 求
1、 一种通过预编码消除远端串音的方法, 其特征在于, 包括: 对信道矩阵进行分块, 分块后的信道矩阵包含若干个子矩阵, 所述子矩阵 中包括强对角占优矩阵和非强对角占优矩阵; 对发送信号进行预编码,并对所述非强对角占优矩阵表示的信道上的发送 信号进行频谱控制, 使预编码后的信号发送功率不超过功率语掩码的限制。
2、 根据权利要求 1所述的方法, 其特征在于: 所述对信道矩阵进行分块包括: 对信道矩阵 Η ΌΌ,ΝΌΌ
H进行分块, 使 H , 其中, HDD为强对角占
H Η 优矩阵, HNDD为非强对角占优矩阵; 所述对发送信号进行预编码,并对所述非强对角占优矩阵表示的信道上的 发送信号进行频谱控制包括: 对发送信号 c 进行预编码, 其中, ¾0表示的强对角占优信道 的发送信号, ½7∞表示的非强对角占优信道的发送信号, 并对 XNDD进行 频语控制, 使预编码后的信号发送功率不超过功率语掩码的限制。
3、根据权利要求 2所述的方法,其特征在于,所述对发送信号进行预编码, 并对所述非强对角占优矩阵表示的信道上的发送信号进行频语控制包括:
计算一个矩阵 Ρ ' , 使 HP ' , 并计算 HDD的预编码矩阵 P:
0 H
HNDD的预编码矩阵 PNDP; 采用预编码矩阵
Figure imgf000020_0001
Ρ = Ρ' 对发送信号 X进行预编码;
0 ΡΛίη, 根据 PNDD计算局部归一化系数 β NDD, β ^0为?^0中各行的行向量的欧几 里得范数的最大值; 采用局部归一化系数 P NDD对预编码后的发送信号 X进行局部归一化,局部
1 0
归一化后的发送信号为 ρ ·
4、根据权利要求 2所述的方法,其特征在于,所述对发送信号进行预编码, 并对所述非强对角占优矩阵表示的信道上的发送信号进行频语控制包括: 计算一个矩阵 Ρ ' , i HP , 并计算 HDD的预编码矩阵 Ρ:
0 Η
HNDD的预编码矩阵 PNDP;
0
采用预编码矩阵 Ρ = Ρ' 对发送信号 χ进行预编码;
0 ΡΑ" 根据 PNDD计算局部归一化系数 β NDD, β ^0为?^0中各行的行向量的欧几 里得范数的最大值; 采用局部归一化系数 P NDD对预编码后的发送信号 X进行局部归一化,局部
1 0
归一化后的发送信号为 ρ · 1 其中 Δ 为经验值£
0
β腸 β
5、根据权利要求 2所述的方法,其特征在于,所述对发送信号进行预编码, 并对所述非强对角占优矩阵表示的信道上的发送信号进行频语控制包括: 计算一个矩阵 并计算 HDD的预编码矩
Figure imgf000021_0001
阵 PDI^PHndd的预编码矩阵 P: 采用预编码矩阵 POP 0
Ρ = Ρ' 对发送信号 X进行预编码, 则预编码后非
0 ,N, 强对角占优矩阵 H,表示的信道的发送信号为 P4PNDPxNDP 根据发送信号 Ρ4ΡΝηΡχΝηΡ对非强对角占优矩阵 H,表示的信道进行频谱优 化。
6、根据权利要求 2所述的方法,其特征在于,所述对发送信号进行预编码, 并对所述非强对角占优矩阵表示的信道上的发送信号进行频语控制包括:
对非强对角占优矩阵 HNDD进行奇异值 SVD分解, 分解后的 H, = UAV" , 其中 U和 V均为酉矩阵, Λ为对角矩阵; 计算预编码矩阵 PNDP = W =v , 联合抵消矩阵 ς
H H
对角占优矩阵 D Τ D,NDD 的预编码矩阵 ;
H A
0 0
采用预编码矩阵 P = A 对发送信号 X进行预编码处理, 预编码后的
0 ,R
0 0
发送信号为 X ,
0 P„r 将计算出的联合抵消矩阵 c = u-l = UH发送给接收端设备; 采用分布式注水算法对非强对角占优矩阵 H^D表示的信道进行频语优化。
7、 一种预编码装置, 其特征在于, 包括:
分块单元, 用于对信道矩阵进行分块, 分块后的信道矩阵包含若干个子矩 阵, 所述子矩阵中包括强对角占优矩阵和非强对角占优矩阵;
预编码单元, 用于对发送信号进行预编码;
频语控制单元,用于对所述非强对角占优矩阵表示的信道上的发送信号进 行频谱控制, 使预编码后的信号发送功率不超过功率语掩码的限制。
8、 根据权利要求 7所述的装置, 其特征在于: 所述分块单元,具体用于对信道矩阵 Η进行分块,使 H
Figure imgf000022_0001
其中, HDD为强对角占优矩阵, HNDD为非强对角占优矩阵; 所述预编码单元,具体用于对发送信号 : 进行预编码,其中, c ,疋 HDD表示的强对角占优信道的发送信号, 是 表示的非强对角占优信道 的发送信号;
所述频谱控制单元, 用于对 xNDD进行频谱控制, 使预编码后的信号发送功 率不超过功率语掩码的限制。
9、 根据权利要求 8所述的装置, 其特征在于: 所述预编码单元, 进一步用于计算一个矩阵 Ρ', 使 HP':
Figure imgf000023_0001
计算 HDD的预编码矩阵 PDP和 HNDD的预编码矩阵 PNDP; 采用预编码矩阵
P = 对发送信号 X进行预编码;
Figure imgf000023_0002
所述频谱控制单元, 用于根据 PNDD计算局部归一化系数 PNDD, P NDD
PNDD中各行的行向量的欧几里得范数的最大值; 采用局部归一化系数 β NDD对 预编码后的发送信号 X进行局部归一化, 局部归一化后的发送信号为
0
Ρ- 1
10、 根据权利要求 8所述的装置, 其特征在于: 所述预编码单元, 进一步用于计算一个矩阵 , 使 HP'
Figure imgf000023_0003
计算 HDD的预编码矩阵 PDP和 HNDD的预编码矩阵 PNDP; 采用预编码矩阵
P = 对发送信号 X进行预编码;
Figure imgf000023_0004
所述频谱控制单元, 用于根据 PNDD计算局部归一化系数 PNDD, P NDD
PNDD中各行的行向量的欧几里得范数的最大值; 采用局部归一化系数 β NDD对 预编码后的发送信号 X进行局部归一化, 局部归一化后的发送信号为 0
Ρ· 1 其中 Δ 为经验值(
β腸 β
11、 根据权利要求 8所述的装置, 其特征在于: 所述预编码单元, 进一步用于计算一个矩阵
Figure imgf000024_0001
HP' 并计算 HDD的预编码矩阵 PDP和 HNDD的预编码矩阵 PNDP; 采
0 H 用预编码矩阵 Ρ = Ρ'. 对发送信号 x进行预编码, 则预编码后非强对角
0 Rn 占优矩阵 表示的信道的发送信号为 P4P醫 X醫 ; 所述频谱控制单元, 用于根据发送信号 APM^ M^对非强对角占优矩阵 H腸表示的信道进行频谱优化。
12、 根据权利要求 8所述的装置, 其特征在于:
所述预编码单元, 进一步用于对非强对角占优矩阵 HNDD进行奇异值 SVD 分解, 分解后的1^ =11八¥", 其中 U和 V均为酉矩阵, Λ为对角矩阵; 计算预 编码矩阵 ^=(0- i = v , 联合抵消矩阵 C^^^tr^t/", 并计算强对角占优矩
H H 0 0 阵 H 的预编码矩阵 采用预编码矩阵 P = A 对发送
H Λ 0 R,r
0 0
信号 x进行预编码处理, 预编码后的发送信号为 X ; 将计算出的联合
0 R,r 4氏消矩阵 = 1 =ί/Η发送给接收端设备;
所述频谱控制单元,用于采用分布式注水算法对非强对角占优矩阵 H^D表 示的信道进行频语优化。
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