CN103067316B

CN103067316B - A kind of crosstalk channel estimation method, device and system

Info

Publication number: CN103067316B
Application number: CN201210587463.3A
Authority: CN
Inventors: 陈兆梅; 王祥; 吕捷; 黄庆
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2012-12-28
Filing date: 2012-12-28
Publication date: 2015-11-25
Anticipated expiration: 2032-12-28
Also published as: CN103067316A; WO2014101847A1

Abstract

The invention discloses a kind of crosstalk channel estimation method, device and system, belong to networking technology area.Described method comprises: according to the cross talk effects data determined in crosstalk channels estimation procedure before, to the non-dead wire in system to dividing into groups, the line of different group between cross talk effects data be less than the first threshold value of setting; The number that under obtaining current group, each group center line is right; The number right according to each group of center line, for each component joins pilot frequency sequence, has a pair not mutually orthogonal pilot frequency sequence at least between different groups; Use the pilot frequency sequence of joining for each component, the crosstalk channels of each group is estimated.Adopt the present invention, the time required for estimation procedure of crosstalk channels can be shortened.

Description

Crosstalk channel estimation method, device and system

Technical Field

The present invention relates to the field of network technologies, and in particular, to a crosstalk channel estimation method, apparatus, and system.

Background

xDSL (digital subscriber line, various types of digital subscriber lines) is a high-speed data transmission technique in telephone twisted pair transmission, using discrete multi-tone modulation. A system providing multiple xDSL access is called a DSLAM (DSL access multiplexer), and due to the principle of electromagnetic induction, multiple signals carried by multiple pairs accessed by the DSLAM may interfere with each other, which is called crosstalk, where the crosstalk may be divided into NEXT (near end crosstalk-Talk) and FEXT (far end crosstalk-Talk), where the near end crosstalk is interference of a transmission signal of a near-end device on a reception signal of the device, and the far end crosstalk is interference of a transmission signal of a far-end device on the reception signal of the device. The uplink and downlink channels of xDSL adopt frequency division multiplexing, so near-end crosstalk does not have a great influence on the performance of the system, and can be generally ignored. Far-end crosstalk can seriously affect the channel rate, so that the system is unstable, and even a line cannot be opened.

In the prior art, a crosstalk cancellation (Vectored-DSL) technique is proposed for reducing or eliminating FEXT, and mainly utilizes the possibility of joint transceiving at a DSLAM end to estimate crosstalk channels, that is, measure and calculate a transmission function between each channel, further calculate an uplink or downlink crosstalk cancellation coefficient, and process signals according to the crosstalk cancellation coefficient to cancel interference of FEXT. The estimation of crosstalk channels and the calculation of crosstalk cancellation coefficients in Vectored-DSL techniques are repeatedly applied during the line initialization process when a subscriber accesses the network and after the line initialization process is completed.

The crosstalk channel H may be represented in a matrix form on any tone (carrier) in the frequency domain, where an element in an ith row and a jth column in the matrix is used to represent a transmission function from a line pair j to a line pair i (the transmission function from a transmitting end of the line pair j to a receiving end of the line pair i may reflect crosstalk generated by a transmission signal of the line pair j to the line pair i). In Vectored-DSL technology, a pilot sequence is selected for each line pair, the pilot sequence may be a binary digit sequence composed of 0 and 1, the pilot sequence represented in a vector form is a vector composed of-1 and 1 (where element 1 of the vector corresponds to binary digit 0 and element-1 of the vector corresponds to binary digit 1), and the pilot sequences of the line pairs are orthogonal to each other in order to calculate a crosstalk channel more accurately. On each line pair, each bit in the pilot sequence is used to modulate and transmit a synchronization symbol (syncsymbol) in turn, and a receiving end receives an error sample (errorsample) obtained through crosstalk on each synchronization symbol. Through the analysis of the pilot sequences and the error samples on the line pairs, the crosstalk channel H can be calculated, and further the crosstalk cancellation coefficient can be obtained.

In the above process, in order to calculate the crosstalk channel more accurately, the length of each pilot sequence should be greater than or equal to the total number of the newly activated (join) line pair and the added (showtime) line pair in the system (in addition, the length of the pilot sequence should be a natural power of 2). The system uses each bit of the corresponding pilot sequence to modulate and transmit the synchronous symbol on each line pair (the first bit is used to modulate and transmit the first synchronous symbol, the second bit is used to modulate and transmit the second synchronous symbol, and so on), so the number of the synchronous symbols required by one time of the crosstalk channel estimation process is the same as the length of the pilot sequence.

In the process of implementing the invention, the inventor finds that the prior art has at least the following problems:

the system generally sends symbols (such as 4000symbol/s, 8000symbol/s, etc.) according to a certain period, and sends a synchronization symbol every time a certain number (such as 256) of data symbols are sent, assuming that the length of the pilot sequence is n, the system needs n synchronization symbols to complete a process of crosstalk channel estimation, and thus, the time required by a process of crosstalk channel estimation is directly proportional to the length of the pilot sequence. Based on the existing Vectored-DSL technology, the length of the pilot sequence is at least the total number of the newly activated line pair and the already on-line pair in the system, and when the number of the newly activated line pair and the already on-line pair in the system is large, the time required for the estimation process of the crosstalk channel is long, and the process of activating the newly activated line pair to be on-line requires the estimation of the crosstalk channel and the calculation process of the crosstalk cancellation coefficient for many times, so the process of activating the newly activated line pair to be on-line is very long.

Disclosure of Invention

In order to solve the problems in the prior art, embodiments of the present invention provide a crosstalk channel estimation method, apparatus, and system, so as to shorten the time required for the estimation process of the crosstalk channel. The technical scheme is as follows:

in one aspect, a crosstalk channel estimation method is provided, in which non-idle line pairs in a system are grouped according to crosstalk influence data determined in a previous crosstalk channel estimation process, and crosstalk influence data between line pairs in different groups is smaller than a set first threshold, and the method includes:

acquiring the number of line pairs in each group under the current group;

allocating pilot sequences for each group according to the number of line pairs in each group, wherein at least one pair of pilot sequences which are not mutually orthogonal is arranged between different groups;

the crosstalk channel of each group is estimated using the pilot sequences assigned to each group.

Preferably, at least one pair of pilot sequences that are not orthogonal to each other between the different groups is:

there is at least one pair of identical pilot sequences between different groups.

Preferably, at least one pair of the same pilot sequences between the different groups includes:

all the pilot sequences allocated to each group are the same as one of the pilot sequences of the groups to which the largest number of pilot sequences are allocated.

Preferably, the estimating of the crosstalk channels of each group is specifically to estimate the crosstalk channels of the on-line pairs of the new active line pairs in each group;

the allocating a pilot sequence for each group according to the number of line pairs in each group specifically comprises:

for the group comprising the newly activated line pair and the on-line pair, distributing the same pilot frequency sequence for the on-line pair, and distributing the pilot frequency sequences with the number of the newly activated line pair as that of the newly activated line pair;

for the group only containing the new active line pair, distributing a pilot frequency sequence with the number of the new active line pair to the new active line pair;

and for the group only containing the on-line pairs, distributing the same pilot frequency sequence for the on-line pairs.

Preferably, the estimating of the crosstalk channels of each group is specifically to estimate crosstalk channels between all pairs in each group;

the allocating a pilot sequence for each group according to the number of line pairs in each group specifically comprises: each pair in the group is assigned a number of pilot sequences corresponding to the number of pairs in the group.

Preferably, in a line initialization process, the row index of the pilot sequence allocated to each new active line pair in the system in the Walsh matrix is kept unchanged in an uplink crosstalk channel estimation process each time;

in the process of estimating an uplink crosstalk channel, when a pilot sequence is distributed to each group according to the number of line pairs in each group, the method for determining the length of the pilot sequence in each group comprises the following steps:

acquiring row indexes of pilot sequences distributed to each new active line pair in a system in a Walsh matrix in a first uplink crosstalk channel estimation process in the line initialization process;

for the group with the number of the line pairs in the group larger than the maximum row index of the new activated line pair in the group and the group without the new activated line pair, determining that the length of the pilot frequency sequence in the group is larger than or equal to the number of the line pairs in the group;

for a group in which the number of pairs in the group is not greater than the maximum row index of a newly activated pair in the group, determining that the length of the pilot sequence in the group is greater than or equal to the maximum row index of the newly activated pair in the group.

acquiring the maximum row index of a pilot sequence distributed to each new active line pair in a system in a Walsh matrix in the first uplink crosstalk channel estimation process of the line initialization process;

if the number of the line pairs of the group with the maximum number of the line pairs is larger than the maximum row index, determining that the lengths of the pilot sequences in all the groups are equal and are larger than or equal to the maximum number of the line pairs;

and if the number of the line pairs of the group with the maximum number of the line pairs is not more than the maximum row index, determining that the lengths of the pilot sequences in the groups are equal and are more than or equal to the maximum row index.

Preferably, the method further comprises the following steps:

if the determined value range of the pilot sequence length contains a preset second threshold value, setting the length of the pilot sequence as the second threshold value;

and if the determined value range of the pilot sequence length does not contain the preset second threshold value, setting the length of the pilot sequence as the minimum natural number power of 2 in the value range.

Preferably, the grouping is performed on the non-idle line pairs in the system according to the crosstalk influence data determined in the previous crosstalk channel estimation process, and the crosstalk influence data between the line pairs in different groups is smaller than a set first threshold, specifically:

in the line initialization process, if an uplink line pair exists in the system, when the first uplink crosstalk channel estimation process and the first downlink crosstalk channel estimation process in the line initialization process are both finished, grouping the non-idle line pairs in the system according to uplink crosstalk influence data between the non-idle line pairs in the system determined in the first uplink crosstalk channel estimation process in the line initialization process and downlink crosstalk influence data between the non-idle line pairs in the system determined in the first downlink crosstalk channel estimation process in the line initialization process, wherein the uplink crosstalk influence data and the downlink crosstalk influence data between the line pairs in different groups are both smaller than a set first threshold value; or,

grouping the uplink crosstalk influence data between the uplink line pairs in the system determined in the uplink crosstalk channel estimation process after the line initialization process is finished, and grouping the downlink crosstalk influence data between the uplink line pairs in the system determined in the downlink crosstalk channel estimation process after the line initialization process is finished, wherein the uplink crosstalk influence data and the downlink crosstalk influence data between the line pairs in different groups are both smaller than a set first threshold value.

Preferably, when there is an abnormal line pair in a non-idle line pair of the system, the non-idle line pair in the system is grouped according to crosstalk influence data determined in a previous crosstalk channel estimation process, and the crosstalk influence data between line pairs of different groups is smaller than a set first threshold, specifically:

according to the crosstalk influence data determined in the previous crosstalk channel estimation process, grouping non-abnormal non-idle line pairs in the system, wherein the crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value; for each group, determining an average value of crosstalk influence data between the abnormal line pair and each line pair in the group; adding the abnormal line pair into a group with the largest average value; or,

according to the crosstalk influence data determined in the previous crosstalk channel estimation process, grouping non-abnormal non-idle line pairs in the system, wherein the crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value; determining the average value of crosstalk influence data of each non-abnormal non-idle line pair on the abnormal line pair; and determining the line pair corresponding to the crosstalk influence data which is larger than the average value in the crosstalk influence data, and adding the abnormal line pair into the group to which the line pair belongs.

In another aspect, a server is provided, including:

the grouping module is used for grouping non-idle line pairs in the system according to the crosstalk influence data determined in the previous crosstalk channel estimation process, wherein the crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value;

the acquisition module is used for acquiring the number of line pairs in each group under the current grouping;

the distribution module is used for distributing pilot frequency sequences for each group according to the number of line pairs in each group, and at least one pair of pilot frequency sequences which are not mutually orthogonal is arranged between different groups;

and the estimation module is used for estimating the crosstalk channels of each group by using the pilot sequences distributed for each group.

Preferably, the allocation module is specifically configured to:

when the pilot sequences are allocated to each group, at least one pair of the same pilot sequences exists between different groups.

Preferably, the allocation module is specifically configured to:

when the pilot sequences are allocated to each group, all the pilot sequences allocated to each group are the same as one of the pilot sequences of the group to which the largest number of pilot sequences are allocated.

Preferably, the estimating module is specifically configured to estimate crosstalk channels of the new active line pairs in each group to the existing line pairs;

the allocation module is specifically configured to:

Preferably, the estimating module is specifically configured to estimate crosstalk channels between all pairs in each group;

the allocation module is specifically configured to: each pair in the group is assigned a number of pilot sequences corresponding to the number of pairs in the group.

in the uplink crosstalk channel estimation process, the allocation module is specifically configured to:

Preferably, the allocation module is further configured to:

Preferably, the grouping module is specifically configured to:

Preferably, when there is an abnormal line pair in a non-idle line pair of the system, the grouping module is specifically configured to:

In another aspect, a crosstalk channel estimation system is provided, which includes a terminal and the server as described above, wherein:

in the process of estimating the crosstalk channels of each group by using the pilot sequences allocated to each group, the terminal is configured to: sending a pilot frequency sequence notified by the server in advance to the server; or receiving an error sample of the pilot sequence sent by the server, and sending the error sample to the server.

The technical scheme provided by the embodiment of the invention has the following beneficial effects:

in the embodiment of the invention, the non-idle line pairs in the system are divided into a plurality of groups with negligible crosstalk, each group can be regarded as an independent system because the crosstalk between the groups can be ignored, and at least one pair of pilot sequences which are not mutually orthogonal is arranged between different groups when the pilot sequences are distributed, so that the number of the pilot sequences which are mutually orthogonal is reduced, the length of the pilot sequences required when crosstalk channel estimation is carried out can be shortened, and the time required by the estimation process of the crosstalk channel can be shortened.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a flowchart of a crosstalk channel estimation method according to an embodiment of the present invention;

fig. 2 is a flowchart of a crosstalk channel estimation method according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a pilot sequence allocation result according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a pilot sequence allocation result according to an embodiment of the present invention;

fig. 5 is a schematic diagram of a pilot sequence allocation result according to an embodiment of the present invention;

fig. 6 is a flowchart of a crosstalk channel estimation method according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a server according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a server according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a crosstalk channel estimation system according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example one

The embodiment of the invention provides a crosstalk channel estimation method, which is to group non-idle line pairs in a system in advance according to crosstalk influence data determined in the previous crosstalk channel estimation process, wherein the crosstalk influence data between the line pairs in different groups is smaller than a set first threshold, and referring to fig. 1, the processing flow of the method can include the following steps:

step 101, obtaining the number of line pairs in each group under the current grouping.

102, distributing pilot sequences for each group according to the number of line pairs in each group, wherein at least one pair of pilot sequences which are not mutually orthogonal exists between different groups.

Step 103, using the pilot sequences allocated to each group, estimating the crosstalk channel of each group.

Example two

The embodiment of the invention provides a crosstalk channel estimation method, which can be controlled and executed by a DSLAM (digital subscriber line access multiplexer) at a network side, wherein after a pilot frequency sequence is determined, a terminal can participate in a subsequent crosstalk channel estimation process. In the method, non-idle line pairs in the system can be grouped in advance according to crosstalk influence data determined in the previous crosstalk channel estimation process, and the crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value. The crosstalk influence data is data indicating the intensity of crosstalk between the respective pairs, and the crosstalk influence data between the pairs may be the absolute value of a crosstalk cancellation coefficient between the pairs or the absolute value of the crosstalk cancellation coefficient multiplied by a preset coefficient. Here, the first threshold may be a preset value, and in addition, preferably, the first threshold may be a product of an average value of crosstalk influence data between non-idle line pairs and a preset adjustment factor (for example, may be set to 1).

The line pairs in the system can be divided into a new activated line pair, an online line pair and an idle (idle) line pair, wherein the new activated line pair is a line pair connected with a terminal which requests to access a network and is initializing, the online line pair is a line pair which is accessed to the network and works, the idle line pair is a line pair which does not request to access the network and is in an idle state, the new activated line pair can become the online line pair after the line initialization process is carried out, and the new activated line pair and the online line pair can be collectively called as a non-idle line pair. The grouping process of the non-idle line pairs will be described in detail later.

Based on the above grouping, the following describes in detail a flow of the crosstalk channel estimation method shown in fig. 1, and a processing flow of the method may include the following steps:

For a certain frequency band, after each grouping, the DSLAM may record related information of the grouping, such as which pairs are included in each group, the number of pairs in each group, and the like, and may replace old grouping information with newly recorded grouping information. Subsequent crosstalk channel estimation procedures may be performed based on the last packet of the band.

102, distributing pilot sequences for each group according to the number of line pairs in each group, wherein at least one pair of pilot sequences which are not mutually orthogonal exists between different groups. The pilot sequences which are not mutually orthogonal are used among different groups, so that the number of the mutually orthogonal pilot sequences in the pilot sequences allocated to all the line pairs can be reduced, and the length of the pilot sequences can be shortened. The pilot sequences allocated to different groups may be the same or different in length, and if different, all pilot sequences between groups are not mutually orthogonal.

If groups are assigned pilot sequences of the same length, there is at least one pair of identical pilot sequences between different groups. Preferably, all the pilot sequences allocated to each group may be the same as one of the pilot sequences in each of the groups to which the largest number of pilot sequences are allocated. In this way, the number of mutually orthogonal pilot sequences in the pilot sequences allocated to all the line pairs is the total number of allocated pilot sequences, that is, the number of pilot sequences of the group with the largest number of allocated pilot sequences.

In the line initialization process, a crosstalk channel estimation process may be performed multiple times, where the crosstalk channel estimation process may be to estimate crosstalk channels of newly activated line pairs to already-activated line pairs, or to estimate crosstalk channels between all non-idle line pairs. For example, in the line initialization process specified by the standard, stages R-P-VECTOR1, R-P-VECTOR1-1 and R-P-VECTOR1-2 are to estimate uplink crosstalk channels of a newly activated line pair to an already uplink line pair, stages O-P-VECTOR1, O-P-VECTOR1-1 and O-P-VECTOR2 are to estimate downlink crosstalk channels of the newly activated line pair to the already uplink line pair, stages R-P-VECTOR2 are to estimate uplink crosstalk channels between all non-idle line pairs, and stages O-P-VECTOR2-1 are to estimate downlink crosstalk channels between all non-idle line pairs. These crosstalk channel estimation procedures described above may all be performed on a packet basis.

Specifically, when estimating the crosstalk channels of the new active line pairs in each group to the line pairs already on the line pairs, the processing of step 102 for different groups may specifically be as follows: for the group comprising the newly activated line pair and the on-line pair, distributing the same pilot frequency sequence for the on-line pair, and distributing the pilot frequency sequences with the number of the newly activated line pair as that of the newly activated line pair; for the group only containing the new active line pair, distributing a pilot frequency sequence with the number of the new active line pair to the new active line pair; and for the group only containing the on-line pairs, distributing the same pilot frequency sequence for the on-line pairs.

In this case, the pilot sequences in the same group are orthogonal to each other, and the same pilot sequence may be used or different pilot sequences may be used for different groups. The on-line pairs in the same group can use the same pilot sequence or mutually orthogonal pilot sequences, and the pilot sequences of the on-line pairs and the newly activated line pairs are mutually orthogonal. So the minimum number of pilot sequences for a group can be the number of new active line pairs within the group plus 1.

Specifically, when estimating the crosstalk channel between all the pairs in each group (i.e., all the non-idle pairs in the group), the process of step 102 may be specifically as follows: each pair in the group is assigned a number of pilot sequences corresponding to the number of pairs in the group.

To accurately estimate the crosstalk channel between the pairs in the group, mutually orthogonal pilot sequences may be assigned to the pairs in the group. The pilot sequences used for each group may be the same or different. For example, L1 belongs to G1, L2 belongs to G2, and the pilot sequences used by L1 and L2 may be the same.

Because the vectors of the rows of the Walsh matrix are orthogonal to each other, one row of the Walsh matrix can be used as a pilot sequence, and the row index can be used to identify which row of the Walsh matrix the pilot sequence corresponds to, a row index of 1 corresponds to the first row, a row index of 2 corresponds to the second row, and so on.

It should be noted that, for different orders of Walsh matrices, the elements in the upper left corner of the low order Walsh matrix and the elements in the upper left corner of the high order Walsh matrix are the same, for example, the first two rows and two columns of the fourth order Walsh matrix are a second order Walsh matrix, so the first n elements of the different orders of Walsh matrices in any same row are the same.

In some cases, the row index of the pilot sequence in the Walsh matrix assigned to each new active line pair in the system can be kept unchanged in each uplink crosstalk channel estimation procedure during one line initialization procedure. As can be seen from the characteristics of the Walsh matrices of different orders, the first n bits of each pilot sequence having the same corresponding row index are the same. In this way, in the first uplink crosstalk channel estimation process, the DSLAM may determine the row index of the pilot sequence in the Walsh matrix after selecting the pilot sequence, and then notify the terminal of the pilot sequence of the preset length (generally, a larger length, for example, 512 bits) corresponding to the row index, and in the subsequent uplink crosstalk channel estimation process, the DSLAM does not need to reselect the pilot sequence and also does not need to send a notification to the terminal. In this case, in the uplink crosstalk channel estimation process, when allocating pilot sequences to each group according to the number of pairs in each group, a method for determining the lengths of the pilot sequences in each group may be as follows:

the method comprises the steps of acquiring a row index of a pilot sequence distributed to each new active line pair in a system in a Walsh matrix in a first uplink crosstalk channel estimation process in a line initialization process; for the group with the number of the line pairs in the group larger than the maximum row index of the new activated line pair in the group and the group without the new activated line pair, determining that the length of the pilot frequency sequence in the group is larger than or equal to the number of the line pairs in the group; for a group in which the number of pairs in the group is not greater than the maximum row index of a newly activated pair in the group, determining that the length of the pilot sequence in the group is greater than or equal to the maximum row index of the newly activated pair in the group. The present line initialization process is an ongoing line initialization process or a line initialization process that has just finished.

Based on the first method, the pilot sequence lengths allocated to the groups may be different. For each group, the length of the pilot sequence is at least the maximum row index of the newly activated line pair in the group, because the row index of the selected pilot sequence for the newly activated line pair is kept constant and the pilot sequences in the group are guaranteed to be orthogonal to each other. Also, the length of the pilot sequence needs to be set to a natural power of 2. It is preferable that the pilot sequence length be set to be greater than or equal to a natural power of 2 of the maximum row index. For some groups, if the number of pairs in the group is greater than the maximum row index, the length of the pilot sequence may be at least the number of pairs in the group to ensure mutual orthogonality of the pilot sequences in the group. At this time, it is preferable that the pilot sequence length be set to be greater than or equal to a natural number power of 2 of the number of pairs of lines in the group.

Acquiring the maximum row index of a pilot sequence distributed to each new active line pair in the system in a Walsh matrix in the first uplink crosstalk channel estimation process of the line initialization process; if the number of the line pairs of the group with the maximum number of the line pairs is larger than the maximum row index, determining that the lengths of the pilot frequency sequences in all the groups are equal and are larger than or equal to the maximum number of the line pairs; and if the number of the line pairs of the group with the maximum number of the line pairs is not more than the maximum row index, determining that the lengths of the pilot sequences in the groups are equal and are more than or equal to the maximum row index.

Based on the second method, the pilot sequences allocated to each group have the same length. That is, all the line pairs in each group are allocated with pilot sequences of the same length, the length of the pilot sequence should satisfy the group with the longest pilot sequence. The number of pairs of the group with the largest number of pairs may be compared with the maximum row index, and if the maximum number of pairs is greater than the maximum row index, it is indicated that the group with the longest required pilot sequence is the group with the largest number of pairs, and the length of the pilot sequence may be set to be at least the maximum number of pairs, preferably greater than or equal to a natural number power of 2 of the maximum number of pairs. If the maximum pair number is not greater than the maximum row index, it indicates that the group with the longest required pilot sequence is the group to which the maximum row index belongs, and the length of the pilot sequence may be set to be at least the maximum row index, and preferably greater than or equal to the natural number power of 2 of the maximum row index.

In addition, in order to make the length of the pilot sequence satisfy the group requiring the longest pilot sequence, a method of the method may also be referred to, the requirement of each group for the length of the pilot sequence is obtained according to the number of line pairs in each group and the maximum row index in the group, and then the maximum length of the pilot sequence is obtained by comparison.

Preferably, the following processes may be added to the processing modes in the first and second methods: if the determined value range of the pilot sequence length contains a preset second threshold value, setting the length of the pilot sequence as the second threshold value; and if the determined value range of the pilot sequence length does not contain the preset second threshold value, setting the length of the pilot sequence as the minimum natural number power of 2 in the value range. With this process, a lower limit of the pilot sequence length can be set so that the pilot sequence length is not lower than the lower limit of the length, and the preset second threshold value is preferably a natural power of 2.

After the DSLAM allocates the pilot sequences to each group, the DSLAM may estimate the crosstalk channels of each group according to the allocated pilot sequences.

When estimating the downlink crosstalk channel, the DSLAM modulates and transmits the synchronization symbol on each non-idle line pair using the corresponding pilot sequence, receives an error sample fed back by each terminal, and then calculates the downlink crosstalk channel according to analysis of the pilot sequence and the error sample.

When estimating the uplink crosstalk channel, after the DSLAM allocates a pilot sequence to each line pair, the DSLAM determines a row index of the pilot sequence in the Walsh matrix, and notifies each pilot sequence of a preset length corresponding to each row index to a terminal connected thereto through a corresponding line pair. After receiving the notification, the terminal modulates the synchronization symbol according to the pilot sequence received by the terminal and sends the synchronization symbol to the DSLAM. And the DSLAM receives the corresponding error sample, and then calculates the uplink crosstalk channel according to the analysis of the pilot frequency sequence and the error sample.

Here, the terminal only needs to perform modulation transmission of the synchronization symbol according to the pilot sequence with the preset length in the notification, and may not know the length of the pilot sequence actually allocated to its line pair by the DSLAM. Thus, for the case that the row index of the pilot sequence allocated to each new active line pair in the system in the Walsh matrix in the uplink crosstalk channel estimation process at each time in the line initialization process described in step 102 is kept unchanged, the length of the pilot sequence may be changed, and the DSLAM may receive the error sample according to the length of the pilot sequence allocated thereto.

The grouping process of the non-idle line pairs will be described in detail below in conjunction with the line initialization process.

In the process of line initialization, crosstalk channel estimation can be carried out for many times, and after the process of line initialization is finished, crosstalk channel estimation can also be carried out for many times to estimate crosstalk channels between the line pairs which are already on the line. The crosstalk channels acquired according to the processes can be grouped, so that crosstalk influence data between the wire pairs of different groups is smaller than a set first threshold value, that is, the crosstalk between the different groups is considered to be negligible. In addition, the grouping can be added under the condition that the crosstalk influence data among the pairs in the group is larger than or equal to a first threshold value, namely, the pairs with mutually non-negligible crosstalk are grouped into one group.

Specifically, in the line initialization process, if there is an existing online pair in the system, the uplink crosstalk influence data of a newly activated pair to the existing online pair in the system can be obtained after the first uplink crosstalk channel estimation process (the stage of R-P-VECTOR1 (uplink direction) in the line initialization process defined by the standard is finished, and the downlink crosstalk influence data of the newly activated pair to the existing online pair in the system can be obtained after the first downlink crosstalk channel estimation process (the stage of O-P-VECTOR1 (downlink direction)) is finished, so preferably, the uplink crosstalk influence data between non-idle pairs in the system determined in the first uplink crosstalk channel estimation process in the line initialization process can be obtained according to the uplink crosstalk influence data between non-idle pairs in the system determined in the first uplink crosstalk channel estimation process in the line initialization process at this time, grouping non-idle line pairs in the system, wherein uplink crosstalk influence data between the line pairs of different groups are smaller than a set first threshold value; or when the first downlink crosstalk channel estimation process in the current line initialization process is finished, grouping the non-idle line pairs in the system according to the downlink crosstalk influence data between the non-idle line pairs in the system determined in the first downlink crosstalk channel estimation process in the current line initialization process, wherein the downlink crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value.

In this way, the subsequent crosstalk channel estimation process may be performed on the basis of the grouping, and certainly, the grouping may be performed again in the subsequent process, so that a more accurate grouping may be obtained.

The process of line initialization can respectively initialize an uplink channel and a downlink channel, the uplink channel and the downlink channel use different frequency bands, crosstalk channels on different frequency bands between line pairs are mutually independent, and therefore the estimation processes of the uplink crosstalk channel and the downlink crosstalk channel can be mutually independent. When non-idle line pairs are grouped, grouping can be performed based on uplink crosstalk influence data or downlink crosstalk influence data, and the two grouping modes do not influence each other.

Preferably, the upstream crosstalk influence data and the downstream crosstalk influence data are considered in combination, and the data may be grouped, that is, in the line initialization process, if there is an existing uplink line pair in the system, when the first uplink crosstalk channel estimation process and the first downlink crosstalk channel estimation process in the current line initialization process are both finished, according to the uplink crosstalk influence data between non-idle line pairs in the system determined in the first uplink crosstalk channel estimation process of the line initialization process at this time, and downlink crosstalk influence data between non-idle line pairs in the system determined in the first downlink crosstalk channel estimation process of the line initialization process at this time, and grouping non-idle line pairs in the system, wherein the uplink crosstalk influence data and the downlink crosstalk influence data between the line pairs of different groups are smaller than a set first threshold value. In addition, the grouping may be increased if the uplink crosstalk influence data and/or the downlink crosstalk influence data between the pairs of lines in the group are greater than or equal to the first threshold value. Thus, pairs whose upstream crosstalk cannot be ignored and/or whose downstream crosstalk cannot be ignored are grouped together. The grouping result can be applied to the subsequent uplink crosstalk channel estimation process and the downlink crosstalk channel estimation process.

Specifically, in the line initialization process, if there is no on-line pair in the system, the line initialization process may only perform a crosstalk channel estimation process in the uplink (or downlink) direction once, and estimate the crosstalk channel between each newly activated line pair in the system, and after performing the uplink crosstalk channel estimation process and the downlink crosstalk channel estimation process once, the newly activated line pair may be on-line and become an on-line pair. In this case, the grouping process may be performed after the line initialization process is finished, and in addition, for the case that the line pair is already on line in the line initialization process system, the grouping may be performed after the line initialization process is finished, and a result of the grouping may be applied to a subsequent crosstalk channel estimation process in a line on line stage (a stage between two line initialization processes, in which a plurality of crosstalk channel estimation processes may be performed).

Preferably, the uplink crosstalk influence data between the uplink line pairs in the system can be grouped according to the uplink crosstalk influence data between the uplink line pairs in the system determined in the uplink crosstalk channel estimation process after the line initialization process is finished, wherein the uplink crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value; the uplink line pairs in the system can also be grouped according to downlink crosstalk influence data between the uplink line pairs in the system determined in a downlink crosstalk channel estimation process performed after the line initialization process is finished, and the downlink crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value. This method can achieve more accurate grouping because the data affected by crosstalk between the pairs may change after the newly activated pair becomes the already-connected pair.

In addition, the uplink crosstalk influence data and the downlink crosstalk influence data may also be considered comprehensively to perform grouping, that is, the uplink crosstalk influence data between the uplink line pairs in the system determined in the uplink crosstalk channel estimation process performed after the line initialization process is finished, and the downlink crosstalk influence data between the uplink line pairs in the system determined in the downlink crosstalk channel estimation process performed after the line initialization process is finished, the uplink line pairs in the system are grouped, and the uplink crosstalk influence data and the downlink crosstalk influence data between the line pairs in different groups are both smaller than the set first threshold value. In addition, the grouping may be increased if the uplink crosstalk influence data and/or the downlink crosstalk influence data between the pairs of lines in the group are greater than or equal to the first threshold value. Thus, pairs whose upstream crosstalk cannot be ignored and/or whose downstream crosstalk cannot be ignored are grouped together.

When there is an abnormal line pair in the non-idle line pairs of the system (e.g., a line pair with an attenuation value exceeding a normal range, a line pair that cannot be brought on line by multiple initializations, a line pair with poor contact, etc.), the grouping process may be specifically as follows: according to the crosstalk influence data determined in the previous crosstalk channel estimation process, grouping non-abnormal non-idle line pairs in the system, wherein the crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value; for each group, determining an average value of crosstalk influence data between the abnormal line pair and each line pair in the group; the pair of abnormal lines is added to the group with the largest average value. The crosstalk influencing data between two pairs comprises crosstalk influencing data of a first pair to a second pair and crosstalk influencing data of the second pair to the first pair.

For example, there are 5 non-idle line pairs L1, L2, L3, L4, L5 in the system, where L5 is an abnormal line pair, then first, L1, L2, L3, L4 are grouped, assuming that the groups are divided into two groups of G1 and G2, G1= { L1, L2}, G2= { L3, L4}, then, the average value of crosstalk influence data of each line pair in L5 and G1 is calculated and recorded as the average value of the crosstalk influence data of each line pair in L5 and G1

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weight_L5→L1Is the crosstalk influence data, weight, of L5 on L1_L1→L5Is the crosstalk influence data, weight, of L1 on L5_L5→L2Is the crosstalk influence data, weight, of L5 on L2_L2→L5The average value of the crosstalk influence data of the pairs of L5 and G2 was calculated in the same manner as the crosstalk influence data of L2 on L5Finally, the comparison is madeAndsuppose thatLarger, L5 was added to G1, resulting in G1= { L1, L2, L5}, and G2= { L3, L4 }.

If there are multiple abnormal non-idle line pairs, after grouping the non-abnormal non-idle line pairs, determining the grouping of each abnormal line pair according to the above method.

In addition, the grouping procedure in the abnormal case may be: according to the crosstalk influence data determined in the previous crosstalk channel estimation process, grouping non-abnormal non-idle line pairs in the system, wherein the crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value; determining the average value of crosstalk influence data of each non-abnormal non-idle line pair on the abnormal line pair; and determining the line pair corresponding to the crosstalk influence data which is larger than the average value in the crosstalk influence data, and adding the abnormal line pair into the group to which the line pair belongs.

It should be noted that the grouping based on the uplink crosstalk influence data may be applied to the subsequent uplink crosstalk channel estimation process, the grouping based on the downlink crosstalk influence data may be applied to the subsequent downlink crosstalk channel estimation process, the grouping based on the uplink crosstalk influence data and the downlink crosstalk influence data may be applied to the subsequent uplink crosstalk channel estimation process and the subsequent row crosstalk channel estimation process.

EXAMPLE III

The crosstalk channel estimation method provided by the embodiment of the present invention is further described below in conjunction with a line initialization process, where a system has an online line pair in the line initialization process, and a specific processing flow may refer to fig. 2, and includes the following steps:

step 201, the DSLAM receives an access request sent by the terminal, and performs a handshake process with the terminal.

Step 202, the DSLAM estimates the downlink crosstalk channel of the new active line pair in the system to the existing online line pair (corresponding to the stage O-P-VECTOR 1), and estimates the uplink crosstalk channel of the new active line pair in the system to the existing online line pair (corresponding to the stage R-P-VECTOR 1).

In this step, non-idle line pairs may not be grouped, the pilot sequence allocation may refer to fig. 3, where L1-L6 are online line pairs, the grouping G1= { L1, L2, L3}, G2= { L4, L5, L6}, and the grouping L7-L12 are newly activated line pairs after the last line initialization process is completed, and the previously existing grouping does not affect the allocation of the pilot sequence at this time. Here L1-L6 are assigned the same pilot sequence.

Step 203, the DSLAM groups the non-idle line pairs in the system according to the downlink crosstalk influence data and the uplink crosstalk influence data determined in the crosstalk channel estimation process. The uplink crosstalk influence data and the downlink crosstalk influence data between the wire pairs in different groups are both smaller than a set first threshold, and the uplink crosstalk influence data and/or the downlink crosstalk influence data between the wire pairs in the groups are not smaller than the first threshold. It is assumed here that the grouping results are: g1= { L1, L2, L3, L7, L8, L9}, G2= { L4, L5, L6, L10, L11, L12 }.

And step 204, in the stages of R-P-VECTOR1-1, R-P-VECTOR1-2, O-P-VECTOR1-1 and O-P-VECTOR2, the DSLAM estimates the uplink or downlink crosstalk channels of the new active line pairs in each group to the existing uplink line pairs based on the grouping.

Specifically, in each of the above stages, first, the DSLAM may obtain the number of the line pairs in each group under the current group, then, the DSLAM allocates the pilot sequences to each group according to the number of the line pairs in each group, and finally, the DSLAM estimates the crosstalk channels of each group according to the pilot sequences allocated to each group.

In step 205, at the stage of R-P-VECTOR2 and O-P-VECTOR2-1, the DSLAM estimates the uplink and downlink crosstalk channels of all the pairs in each group based on the above grouping. The specific process is as above, and will not be described in detail.

In the crosstalk channel estimation process in each stage of the above steps 204 and 205, the pilot sequences may be allocated as shown in fig. 4 or fig. 5, different groups may use the same pilot sequence or different pilot sequences, in the allocation manner shown in fig. 4, the row index in step 202 is not used by the newly activated line pair, and in the allocation manner shown in fig. 5, the row index in step 202 is used by the newly activated line pair. In fig. 4 and 5, the on-line pairs in the group are allocated with mutually orthogonal pilot sequences, and for each stage in step 204, the same pilot sequences may also be allocated to the on-line pairs in the group.

In step 206, the newly activated line pair becomes an online line pair, and the line initialization is completed. At this stage, the work of channel analysis, data interaction and the like can be carried out.

Further, after step 206, the DSLAM may also estimate crosstalk channels of all the online line pairs in the system, group the online line pairs according to the uplink crosstalk influence data and the downlink crosstalk influence data obtained in the crosstalk channel estimation process, and perform subsequent crosstalk channel estimation in a line online stage (a stage between two line initialization processes, in which a plurality of crosstalk channel estimation processes may be performed) according to a new grouping result.

According to the finally obtained crosstalk channels in the uplink and downlink directions of each group, a crosstalk cancellation coefficient can be further calculated, and signals received and sent by the on-line pairs in the system in the subsequent data transmission process can be processed according to the crosstalk cancellation coefficient, so that the system crosstalk is reduced.

Example four

The crosstalk channel estimation method provided by the embodiment of the present invention is further described below in combination with a line initialization process and a subsequent line online stage, where no online line pair exists in a system in the line initialization process, and a specific processing flow may be as shown in fig. 6, and includes the following steps:

step 601, the DSLAM receives an access request sent by the terminal, and performs a handshake process with the terminal.

In step 602, at the stage of R-P-VECTOR2 and O-P-VECTOR2-1, the DSLAM estimates the upstream and downstream crosstalk channels between all newly activated pairs. Because no online line pair exists in the system, the stages of O-P-VECTOR1, R-P-VECTOR1, R-P-VECTOR1-1, R-P-VECTOR1-2, O-P-VECTOR1-1 and O-P-VECTOR2 can be omitted.

Step 603, the newly activated line pair becomes an online line pair, and the line initialization is completed. At this stage, the work of channel analysis, data interaction and the like can be carried out.

In step 604, the DSLAM estimates uplink and downlink crosstalk channels of all the online line pairs in the system, and groups the online line pairs according to the uplink crosstalk influence data and the downlink crosstalk influence data obtained in the crosstalk channel estimation process.

In step 605, the DSLAM performs subsequent crosstalk channel estimation in the line-on stage (the stage between two line initialization processes, in which a plurality of crosstalk channel estimation processes may be performed) according to the new grouping result.

EXAMPLE five

Based on the same technical concept, an embodiment of the present invention provides a server, referring to fig. 7, including:

a grouping module 710, configured to group non-idle line pairs in the system according to crosstalk influence data determined in a previous crosstalk channel estimation process, where the crosstalk influence data between different groups of line pairs is smaller than a set first threshold;

an obtaining module 720, configured to obtain the number of line pairs in each group under the current grouping;

an allocating module 730, configured to allocate pilot sequences to each group according to the number of line pairs in each group, where at least one pair of pilot sequences that are not mutually orthogonal is located between different groups;

and an estimating module 740, configured to estimate the crosstalk channels of the groups by using the pilot sequences allocated to the groups.

Preferably, the allocating module 730 is specifically configured to:

Preferably, the estimating module 740 is specifically configured to estimate crosstalk channels of the newly activated line pairs in each group on the already-on line pairs;

the allocating module 730 is specifically configured to:

Preferably, the estimating module 740 is specifically configured to estimate crosstalk channels between all pairs in each group;

the allocating module 730 is specifically configured to: each pair in the group is assigned a number of pilot sequences corresponding to the number of pairs in the group.

in the uplink crosstalk channel estimation process, the allocating module 730 is specifically configured to:

Preferably, the allocating module 730 is further configured to:

Preferably, the grouping module 710 is specifically configured to:

Preferably, when there is an abnormal line pair in a non-idle line pair of the system, the grouping module 710 is specifically configured to:

EXAMPLE six

Based on the same technical concept, an embodiment of the present invention provides a server, referring to fig. 8, the server including a processor 810 and a memory 820, the processor 810 and the memory 820 being configured to perform the following operations:

according to the crosstalk influence data determined in the previous crosstalk channel estimation process, grouping non-idle line pairs in the system, wherein the crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value; acquiring the number of line pairs in each group under the current group; allocating pilot sequences for each group according to the number of line pairs in each group, wherein at least one pair of pilot sequences which are not mutually orthogonal is arranged between different groups; the crosstalk channel of each group is estimated using the pilot sequences assigned to each group.

Preferably, the method further comprises the following steps:

EXAMPLE seven

Based on the same technical concept, an embodiment of the present invention provides a crosstalk channel estimation system, referring to fig. 9, including a terminal 910 and a server 920 as described in the above embodiment, where:

in the process of estimating the crosstalk channels of each group by using the pilot sequences allocated to each group, the terminal 910 is configured to: sending a pilot sequence notified in advance by the server 920 to the server 920; or, receive the error sample of the pilot sequence sent by the server 920, and send the error sample to the server 920.

It should be noted that: in the crosstalk channel estimation apparatus provided in the above embodiment, when estimating a crosstalk channel, only the division of each functional module is illustrated, and in practical applications, the above function distribution may be completed by different functional modules according to needs, that is, the internal structure of the apparatus is divided into different functional modules, so as to complete all or part of the above described functions. In addition, the crosstalk channel estimation apparatus and the crosstalk channel estimation method provided in the above embodiments belong to the same concept, and specific implementation processes thereof are described in the method embodiments and are not described herein again.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, where the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A method for crosstalk channel estimation, the method comprising: according to the crosstalk influence data determined in the previous crosstalk channel estimation process, grouping non-idle line pairs in the system, wherein the crosstalk influence data between the line pairs in different groups is smaller than a set first threshold value;

acquiring the number of line pairs in each group under the current group;

estimating the crosstalk channels of each group by using the pilot sequences distributed to each group;

the method includes the steps of grouping non-idle line pairs in a system according to crosstalk influence data determined in a previous crosstalk channel estimation process, wherein the crosstalk influence data between different groups of line pairs is smaller than a set first threshold, and specifically includes: in the line initialization process, if an uplink line pair exists in the system, when the first uplink crosstalk channel estimation process and the first downlink crosstalk channel estimation process in the line initialization process are both finished, grouping the non-idle line pairs in the system according to uplink crosstalk influence data between the non-idle line pairs in the system determined in the first uplink crosstalk channel estimation process in the line initialization process and downlink crosstalk influence data between the non-idle line pairs in the system determined in the first downlink crosstalk channel estimation process in the line initialization process, wherein the uplink crosstalk influence data and the downlink crosstalk influence data between the line pairs in different groups are both smaller than a set first threshold value; or grouping the uplink crosstalk influence data among the uplink line pairs in the system according to the uplink crosstalk influence data among the uplink line pairs in the system determined in the uplink crosstalk channel estimation process after the line initialization process is finished and the downlink crosstalk influence data among the uplink line pairs in the system determined in the downlink crosstalk channel estimation process after the line initialization process is finished, wherein the uplink crosstalk influence data and the downlink crosstalk influence data among the line pairs in different groups are both smaller than a set first threshold value.

2. The method of claim 1, wherein at least one pair of pilot sequences between the different groups is not orthogonal to each other, and specifically:

3. The method of claim 2, wherein at least one pair of identical pilot sequences between the different groups is:

4. The method according to claim 1, wherein the estimating crosstalk channels of each group is performed, specifically, the estimating crosstalk channels of the newly activated line pair in each group to the already on-line pair;

5. The method according to claim 1, wherein the estimating of the crosstalk channels of each group is performed, specifically, estimating the crosstalk channels between all pairs in each group;

6. The method of claim 1, wherein in a line initialization process, the row index of the pilot sequence in the Walsh matrix assigned to each new active line pair in the system is kept unchanged in each uplink crosstalk channel estimation process;

7. The method of claim 1, wherein in a line initialization process, the row index of the pilot sequence in the Walsh matrix assigned to each new active line pair in the system is kept unchanged in each uplink crosstalk channel estimation process;

8. The method of claim 6 or 7, further comprising:

9. The method according to claim 1, wherein when there is an abnormal line pair in a non-idle line pair of a system, the non-idle line pair in the system is grouped according to crosstalk influence data determined in a previous crosstalk channel estimation process, and the crosstalk influence data between different groups of line pairs is smaller than a set first threshold, specifically:

10. A server, characterized in that the server comprises:

the estimation module is used for estimating the crosstalk channels of each group by using the pilot sequences distributed for each group;

wherein the grouping module is specifically configured to: in the line initialization process, if an uplink line pair exists in the system, when the first uplink crosstalk channel estimation process and the first downlink crosstalk channel estimation process in the line initialization process are both finished, grouping the non-idle line pairs in the system according to uplink crosstalk influence data between the non-idle line pairs in the system determined in the first uplink crosstalk channel estimation process in the line initialization process and downlink crosstalk influence data between the non-idle line pairs in the system determined in the first downlink crosstalk channel estimation process in the line initialization process, wherein the uplink crosstalk influence data and the downlink crosstalk influence data between the line pairs in different groups are both smaller than a set first threshold value; or grouping the uplink crosstalk influence data among the uplink line pairs in the system according to the uplink crosstalk influence data among the uplink line pairs in the system determined in the uplink crosstalk channel estimation process after the line initialization process is finished and the downlink crosstalk influence data among the uplink line pairs in the system determined in the downlink crosstalk channel estimation process after the line initialization process is finished, wherein the uplink crosstalk influence data and the downlink crosstalk influence data among the line pairs in different groups are both smaller than a set first threshold value.

11. The server according to claim 10, wherein the allocation module is specifically configured to:

12. The server according to claim 11, wherein the allocation module is specifically configured to:

13. The server according to claim 10, wherein the estimating module is specifically configured to estimate crosstalk channels of new active line pairs in each group on already-on line pairs;

the allocation module is specifically configured to:

14. The server according to claim 10, wherein the estimating module is specifically configured to estimate crosstalk channels between all pairs in each group;

15. The server according to claim 10, wherein the row index of the pilot sequence in the Walsh matrix allocated to each new active line pair in the system in each uplink crosstalk channel estimation procedure is kept unchanged during a line initialization procedure;

16. The server according to claim 10, wherein the row index of the pilot sequence in the Walsh matrix allocated to each new active line pair in the system in each uplink crosstalk channel estimation procedure is kept unchanged during a line initialization procedure;

17. The server according to claim 15 or 16, wherein the allocation module is further configured to:

18. The server according to claim 10, wherein when there is an abnormal line pair in a non-idle line pair of the system, the grouping module is specifically configured to:

19. A crosstalk channel estimation system comprising a terminal and a server according to claims 10-18, wherein: