WO2017008308A1

WO2017008308A1 - Method of increasing transmission rate and device utilizing same

Info

Publication number: WO2017008308A1
Application number: PCT/CN2015/084255
Authority: WO
Inventors: 殷慧; 孙方林
Original assignee: 华为技术有限公司
Priority date: 2015-07-16
Filing date: 2015-07-16
Publication date: 2017-01-19
Also published as: CN107852385A; CN107852385B

Abstract

An embodiment of the invention provides a method of increasing a transmission rate, comprising: obtaining, at a transmission end, a precoding coefficient P as indicated by , wherein H^-1 is an inverse matrix of a channel transfer matrix H on M twisted pairs, and is a diagonal matrix by taking a direct channel in the channel transfer matrix H as a principle diagonal element; performing, according to the precoding coefficient P, precoding on a signal to be transmitted on the M twisted pairs; and transmitting the signal to be transmitted after precoding. Also provided in another embodiment of the invention is a device capable of increasing a transmission rate.

Description

Line rate increasing method and device

Technical field

The present invention relates to the field of data communications, and in particular to a method and apparatus for improving line rate.

Background technique

Digital Subscriber Line (DSL) is a high-speed data transmission technology for transmission over twisted pair lines, such as Unshielded Twist Pair (UTP). DSL systems have multiple DSL lines. Currently, DSLAM (Digital Subscriber Line Access Multiplexer) provides multiple DSL access for multiple Customer Premises Equipment (CPE). However, due to the principle of electromagnetic induction, crosstalk is generated between multiple signals connected to the DSLAM. As shown in Figure 1. The twisted pair is very strong at high frequency Far-end Crosstalk (FEXT). To eliminate the noise caused by crosstalk, for example, Vectored DSL technology can be used to eliminate far-end crosstalk on multiple DSL lines. When the Vector technology is not used, most lines can only reach 20-30% of the rate at which a single line is activated (ie, the rate at which there is no crosstalk). However, if Vector technology is used, a higher rate can be obtained on the line, but at most it can only reach about 95% of the rate without crosstalk.

Summary of the invention

Embodiments of the present invention provide a line rate lifting method and apparatus to increase the rate of a line.

In a first aspect, an embodiment of the present invention provides a method for improving a line rate, including:

At the transmitting end, obtaining a precoding coefficient P,

Where H ^-1 represents the inverse matrix of the channel transmission matrix H on the M twisted pairs,

a diagonal matrix in which the direct channel in the channel transmission matrix H is a main diagonal element; ΔH _k is a matrix except that the kth main diagonal element is Δh _kk and the remaining elements are all 0.

Where N represents the number of lines of the transmission power that need to be adjusted, and 1 ≤ N ≤ M;

The phase difference between the direct channel h _kk and the line k is

The crosstalk channel h _ki is an element of a set formed by arranging amplitude values from large to small;

Precoding the signals to be transmitted on the M twisted pairs by using the precoding coefficient P;

Transmitting the pre-coded signal to be transmitted.

In a first possible implementation manner of the first aspect, the channel transmission matrix H on the M twisted pairs is represented as

Wherein, the diagonal element h _ii represents the direct channel of line i, and the non-diagonal element h _ij represents the crosstalk channel of line j to line i, 1 ≤ i ≤ M, 1 ≤ j ≤ M, and i ≠ j;

Can be expressed as

Where h _MM represents the direct channel of line M; ΔH _k can be expressed as

In conjunction with the first aspect or the first possible implementation of the first aspect, in a second possible implementation, the ΔH _k is obtained by:

In the set of crosstalk channels of line k and other lines of the M lines to line k, ie, _Hk , the phase difference between the direct channel h _kk and the line k of the line k is searched for.

The crosstalk channel h _ki between them forms a set S,

Where angle(h _ki ,h _kk ) represents the phase difference between the crosstalk channel h _ki and h _kk ; the elements of S are arranged according to the amplitude values from large to small, resulting in a set

among them

Express

Amplitude; then by

Obtain ΔH _k .

In combination with the first aspect, the first possible implementation manner of the first aspect, or the second possible implementation manner of the first aspect, in a third possible implementation manner, the method further includes

Obtaining an updated precoding coefficient P',

Where ΔH _g is a matrix except that the gth main diagonal element is Δh _gg and the remaining elements are all 0.

and

The phase difference between the direct channel h _gg and the line g is

The crosstalk channel h _gi is an element of a set formed by arranging the amplitude values from large to small.

And precoding the signals to be transmitted on the M twisted pairs by using the P′; and transmitting the precoded signals to be sent.

In a second aspect, an embodiment of the present invention provides a device for improving a line rate, including: a precoding coefficient acquiring unit 31, a precoder 32, and a transmitter 33;

The precoding coefficient obtaining unit 31 is configured to obtain a precoding coefficient P, where

The phase difference between the direct channel h _kk and the line k is

The precoder 32 is configured to precode the to-be-transmitted signal on the M twisted pairs by using the precoding coefficient P;

The transmitter 33 is configured to send the pre-coded signal to be transmitted.

In a first possible implementation manner of the second aspect, the channel transmission matrix H on the M twisted pairs is represented as

Can be expressed as

Where h _MM represents the direct channel of line M; ΔH _k can be expressed as

With reference to the second aspect or the first possible implementation manner of the second aspect, in the second possible implementation manner, the pre-coding coefficient acquiring unit 31 is further configured to obtain ΔH _k , specifically, including:

The crosstalk channel h _ki between them forms a set S,

among them

Express

Amplitude; then by

Obtain ΔH _k .

With reference to the second aspect, the first possible implementation manner of the second aspect, or the second possible implementation manner of the second aspect, in a third possible implementation manner, the precoding coefficient acquisition unit 31 obtains the update After the precoding coefficient P' is sent to the precoder,

and

The phase difference between the direct channel h _gg and the line g is

The precoder uses the P' to precode the signals to be transmitted on the M twisted pairs.

In a third aspect, an embodiment of the present invention provides a device for improving a line rate, including: a receiver 41, a processor 42, and a transmitter 43.

a receiver 41, configured to acquire a channel transmission matrix H on the M twisted pairs; specifically, H is represented as

The processor 42 is configured to calculate a precoding coefficient P, where

The phase difference between the direct channel h _kk and the line k is

The crosstalk channel h _ki is an element of a set formed by arranging the amplitude values from large to small; using the precoding coefficient P to precode the signals to be transmitted on the M twisted pairs;

The transmitter 43 is configured to send the pre-coded signal to be sent.

In a first possible implementation manner of the third aspect, the channel transmission matrix H on the M twisted pairs is represented as

Can be expressed as

Where h _MM represents the direct channel of line M; ΔH _k can be expressed as

By adopting the scheme described in this embodiment, by precoding the signal to be transmitted on the line by using a specific precoding coefficient, each line can increase a part of the transmission power while transmitting a signal on its own line with a certain power. The speed of the crosstalk is suppressed while the speed of one or more lines is increased.

DRAWINGS

FIG. 1 is a schematic diagram of a network of multiple DSL accesses;

2 is a schematic flowchart of a method according to an embodiment of the present invention;

3 is a schematic structural diagram of a device according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of still another apparatus according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. It is a partial embodiment of the invention, and not all of the embodiments. based on All other embodiments obtained by those skilled in the art without creative efforts are within the scope of the present invention.

In order to eliminate the crosstalk on the line, the transmission signal may be pre-compensated on the network side (the CO side) according to the crosstalk parameter fed back on the user side (ie, the CPE side), and the technique is called Vectoring processing; The vectorization processing device is a Vectoring Control Entity (VCE) in the DSLAM. The existing Vectored DSL technology mainly utilizes the feature of joint transmission and reception at the DSLAM end, and uses signal processing methods to offset the interference of FEXT. Finally, the FEXT interference in each signal is eliminated. Corresponding to FIG. 1, the downlink and uplink shared channels between the DSLAM and the CPE are labeled H, which can be represented in a matrix form on one of the frequency domains f ₀ in the frequency domain:

Among them, the diagonal element h _ii represents the direct channel of line i, and the non-diagonal element h _ij represents the crosstalk channel of line j to line i. Using H _i =[h _i1 h _i2 ... h _iM ], the direct channel of line i and the set of crosstalk channels of line i to line i are shown. It can be seen that H _i is the ith line corresponding to the H matrix.

Here, the number of lines is set to M, then H is an M x M channel transmission matrix. Further, x is an M×1 channel input vector, y is an M×1 channel output vector, and n is an M×1 noise vector. Finally, the channel transfer equation is expressed as follows:

y=Hx+n

In the downlink signal transmission process, the joint transmission processing of the signal is performed at the CO end, and a precoder is introduced at the CO end, and the coding coefficient is denoted as P, and the transmitted signal is:

The signal received at the receiving end is:

When HP is a diagonal array

When the crosstalk noise is removed, at this time

Where H ^-1 represents the inverse matrix of the channel transmission matrix H.

On the basis of the Vectoring technology, the embodiment of the present invention further adjusts the coefficient P of the precoder to increase the transmission power on a part of the line to increase the rate on one or more lines while suppressing the noise caused by the crosstalk.

The following describes an example of how to adjust the coefficient P of the precoder by increasing the rate of the line k at the subcarrier f ₀ as an example.

First, the phase difference between the direct channel h _kk and the line _k is searched in H _k at

The crosstalk channel h _ki between them forms a set S:

Where angle(h _ki ,h _kk ) represents the phase difference between the crosstalk channels h _ki and h _kk .

The elements of S are arranged according to the amplitude values from large to small to obtain a set.

among them

Express

Amplitude.

It is assumed that on the subcarrier f ₀ , it is necessary to adjust the transmission power of the N lines to speed up the line k, where 1 ≤ N ≤ M; the target channel of the line k

For the sum of the direct channel h _kk and the channel increment Δh _kk , ie

The increment of the target channel relative to the direct channel is:

Then the target channel of line k

Can also be expressed as

Suppose we only need to speed up line k, then the target channel on the remaining M-1 lines except line k should be equal to the direct channel, ie the channel increment is 0, recorded as

And i≠k. Target channel matrix

for:

among them

That is, the diagonal matrix of the direct channel is the diagonal element;

That is, a matrix other than the kth main diagonal element is Δh _kk , and all other elements are 0.

Then the coefficient P of the precoder is

Further, if there is still a need to speed up other lines, if it is also necessary to speed up the line i, then

The embodiment of the present invention can pre-code the signal to be transmitted on the line by using a specific precoding coefficient on any time slice and spectrum segment, so that each line can transmit a signal on its own line with a certain power while adding a part. The transmission power accelerates the speed of a certain line or lines while suppressing noise caused by crosstalk.

Correspondingly, the embodiment of the present invention provides a method for improving a line rate. As shown in FIG. 2, the method includes:

Step 201, at the transmitting end, obtaining a precoding coefficient P,

The phase difference between the direct channel h _kk and the line k is

Step 203: Perform precoding on the M twisted pair lines by using the precoding coefficient P.

Step 205: Send the pre-coded signal to be sent.

This can improve the line rate of line k.

Further, the channel transmission matrix H on the M twisted pairs is represented as

Can be expressed as

Where h _MM represents the direct channel of line M; ΔH _k can be expressed as

Further, the ΔH _k is obtained by the following method:

The crosstalk channel h _ki between them forms a set S,

among them

Express

Amplitude; then by

Obtain ΔH _k .

It should be noted that since h _ki and h _kk are both complex numbers, there is a phase difference between the two.

Further, after step 205, an updated precoding coefficient P' is obtained,

and

The phase difference between the direct channel h _gg and the line g is

Using the P' to precode the signals to be transmitted on the M twisted pairs. Of course, the to-be-transmitted signal is data to be transmitted at the transmitting end after the point in time at which the coefficient P' is obtained. After that, the pre-coded signal to be transmitted is sent out.

This makes it possible to increase the line rate of line k and line g.

Similarly, if you need to increase the line rate of other lines i or more, just update the precoding coefficient P to the above way.

And pre-coding the transmitted signal with the updated pre-coding coefficient P can be realized.

In the embodiment of the present invention, by using a specific precoding coefficient to precode the signal to be transmitted on the line, each line can increase a part of the transmission power under the premise of transmitting the signal on the line with a certain power, and the crosstalk is caused to be suppressed. The noise is simultaneously increased for one or more lines. In this embodiment, all the lines in the M lines can be speed-up, and the speed can be speeded up according to requirements. In addition, although the present embodiment is described for a single subcarrier, the line can be speeded up in each of the subcarriers in the above manner on a plurality of subcarriers.

The embodiment of the present invention further provides a line rate boosting device 30, as shown in FIG. 3, comprising a precoding coefficient obtaining unit 31, a precoder 32 and a transmitter 33;

The phase difference between the direct channel h _kk and the line k is

The precoder 32 precodes the to-be-transmitted signal on the M twisted pairs by using the precoding coefficient P;

The transmitter 33 transmits the precoded signal to be transmitted.

Can be expressed as

Where h _MM represents the direct channel of line M; ΔH _k can be expressed as

Further, the ΔH _k is obtained by the precoding coefficient acquisition unit 31 by the following method:

The crosstalk channel h _ki between them forms a set S,

among them

Express

Amplitude; then by

Obtain ΔH _k .

Further, after the precoding coefficient obtaining unit 31 obtains the updated precoding coefficient P′, it sends it to the precoder 32, where

and

The phase difference between the direct channel h _gg and the line g is

The precoder 32 pre-codes the to-be-transmitted signal on the M twisted pairs by using the P'; of course, the to-be-transmitted signal is the time when the pre-coding coefficient acquisition unit 31 obtains the coefficient P' The data to be sent at the transmitting end after the point. Thereafter, the pre-encoded signal to be transmitted is transmitted by the transmitter 33.

This makes it possible to increase the line rate of line k and line g.

In the embodiment of the present invention, by using a specific precoding coefficient to precode the signal to be transmitted on the line, each line can increase a part of the transmission power under the premise of transmitting the signal on the line with a certain power, and the crosstalk is caused to be suppressed. The noise is simultaneously increased for one or more lines.

It should be further noted that the specific actions performed by the precoding coefficient acquisition unit and the precoder in the network side device are the methods in the foregoing method embodiments.

The embodiment of the present invention further provides another device for improving the line rate. As shown in FIG. 4, the device 40 includes a receiver 41, a processor 42, and a transmitter 43.

a processor 42, configured to calculate a precoding coefficient P,

The phase difference between the direct channel h _kk and the line k is

The transmitter 43 is configured to send the pre-coded signal to be sent.

In the above embodiment, it should be understood that the processor may be a central processing unit (English: Central Processing Unit, CPU for short), or may be other general-purpose processors, digital signal processors (English: Digital Signal Processor, referred to as: DSP), Application Specific Integrated Circuit (ASIC). The general purpose processor may be a microprocessor or the processor or any conventional processor or the like. The steps of the method disclosed in the embodiments of the present invention may be directly implemented as a hardware processor, or may be performed by a combination of hardware and software modules in the processor.

A person skilled in the art can understand that all or part of the steps of implementing the above method embodiments may be completed by using hardware related to the program instructions. The foregoing program may be stored in a computer readable storage medium, and the program is executed when executed. The foregoing steps include the steps of the foregoing method embodiments; and the foregoing storage medium includes: a medium that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk. The network processing described in detail above may be implemented on a general purpose component such as a computer or network component having sufficient processing power, memory resources, and network throughput capabilities.

Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

Claims

A method for improving a line rate, comprising:

At the transmitting end, obtaining a precoding coefficient P,
Where H -1 represents the inverse matrix of the channel transmission matrix H on the M twisted pairs,
a diagonal matrix in which the direct channel in the channel transmission matrix H is a main diagonal element; ΔH k is a matrix except that the kth main diagonal element is Δh kk and the remaining elements are all 0.
Where N represents the number of lines of the transmission power that need to be adjusted, and 1 ≤ N ≤ M;
The phase difference between the direct channel h kk and the line k is
The crosstalk channel h ki is an element of a set formed by arranging amplitude values from large to small;

Precoding the signals to be transmitted on the M twisted pairs by using the precoding coefficient P;

Transmitting the pre-coded signal to be transmitted.
The method of claim 1 wherein said M twisted pair channel transmission matrix H is represented as
Wherein, the diagonal element h ii represents the direct channel of line i, and the non-diagonal element h ij represents the crosstalk channel of line j to line i, 1 ≤ i ≤ M, 1 ≤ j ≤ M, and i ≠ j;
Can be expressed as
Where h MM represents the direct channel of line M; ΔH k can be expressed as
The method according to claim 1 or 2, wherein said ΔH k is obtained by the following method:

In the set of crosstalk channels of line k and other lines of the M lines to line k, ie, Hk , the phase difference between the direct channel h kk and the line k of the line k is searched for.
The crosstalk channel h ki between them forms a set S,
Where angle(h ki ,h kk ) represents the phase difference between the crosstalk channel h ki and h kk ; the elements of S are arranged according to the amplitude values from large to small, resulting in a set

among them
Express
Amplitude; then by
Obtain ΔH k .
A method according to any one of claims 1 to 3, wherein the method further comprises

Obtaining an updated precoding coefficient P',
Where ΔH g is a matrix except that the gth main diagonal element is Δh gg and the remaining elements are all 0.
and
The phase difference between the direct channel h gg and the line g is
The crosstalk channel h gi is an element of a set formed by arranging the amplitude values from large to small.

And precoding the signals to be transmitted on the M twisted pairs by using the P′; and transmitting the precoded signals to be sent.
A device for improving a line rate, comprising: a precoding coefficient acquiring unit 31, a precoder 32 and a transmitter 33;

The precoding coefficient obtaining unit 31 is configured to obtain a precoding coefficient P, where
Where H -1 represents the inverse matrix of the channel transmission matrix H on the M twisted pairs,
a diagonal matrix in which the direct channel in the channel transmission matrix H is a main diagonal element; ΔH k is a matrix except that the kth main diagonal element is Δh kk and the remaining elements are all 0.
Where N represents the number of lines of the transmission power that need to be adjusted, and 1 ≤ N ≤ M;
The phase difference between the direct channel h kk and the line k is
The crosstalk channel h ki is an element of a set formed by arranging the amplitude values from large to small;

The precoder 32 is configured to precode the to-be-transmitted signal on the M twisted pairs by using the precoding coefficient P;

The transmitter 33 is configured to send the pre-coded signal to be transmitted.
The apparatus according to claim 5, wherein said M twisted pair channel transmission matrix H is represented as

Wherein, the diagonal element h ii represents the direct channel of line i, and the non-diagonal element h ij represents the crosstalk channel of line j to line i, 1 ≤ i ≤ M, 1 ≤ j ≤ M, and i ≠ j;
Can be expressed as
Where h MM represents the direct channel of line M; ΔH k can be expressed as
The apparatus according to claim 5 or 6, wherein the precoding coefficient acquisition unit 31 is further configured to obtain ΔH k , specifically comprising:

In the set of crosstalk channels of line k and other lines of the M lines to line k, ie, Hk , the phase difference between the direct channel h kk and the line k of the line k is searched for.
The crosstalk channel h ki between them forms a set S,
Where angle(h ki ,h kk ) represents the phase difference between the crosstalk channel h ki and h kk ; the elements of S are arranged according to the amplitude values from large to small, resulting in a set

among them
Express
Amplitude; then by
Obtain ΔH k .
The apparatus according to any one of claims 5 to 7, wherein the precoding coefficient obtaining unit 31 obtains the updated precoding coefficient P' and sends it to the precoder,
Where ΔH g is a matrix except that the gth main diagonal element is Δh gg and the remaining elements are all 0.
and
The phase difference between the direct channel h gg and the line g is
The crosstalk channel h gi is an element of a set formed by arranging the amplitude values from large to small.

The precoder uses the P' to precode the signals to be transmitted on the M twisted pairs.
A device for improving a line rate, comprising: a receiver 41, a processor 42, and a transmitter 43.

a receiver 41, configured to acquire a channel transmission matrix H on the M twisted pairs; specifically, H is represented as

a processor 42, configured to calculate a precoding coefficient P,
Where H -1 represents the inverse matrix of the channel transmission matrix H on the M twisted pairs,
a diagonal matrix in which the direct channel in the channel transmission matrix H is a main diagonal element; ΔH k is a matrix except that the kth main diagonal element is Δh kk and the remaining elements are all 0.
Where N represents the number of lines of the transmission power that need to be adjusted, and 1 ≤ N ≤ M;
The phase difference between the direct channel h kk and the line k is
The crosstalk channel h ki is an element of a set formed by arranging the amplitude values from large to small; using the precoding coefficient P to precode the signals to be transmitted on the M twisted pairs;

The transmitter 43 is configured to send the pre-coded signal to be sent.
The apparatus according to claim 9, wherein said M twisted pair channel transmission matrix H is represented as

Wherein, the diagonal element h ii represents the direct channel of line i, and the non-diagonal element h ij represents the crosstalk channel of line j to line i, 1 ≤ i ≤ M, 1 ≤ j ≤ M, and i ≠ j;
Can be expressed as
Where h MM represents the direct channel of line M; ΔH k can be expressed as