WO2012171201A1

WO2012171201A1 - Activation method and apparatus for newly joined line pairs in xdsl system, and xdsl system

Info

Publication number: WO2012171201A1
Application number: PCT/CN2011/075809
Authority: WO
Inventors: 王祥; 刘立贺; 李程
Original assignee: 华为技术有限公司
Priority date: 2011-06-16
Filing date: 2011-06-16
Publication date: 2012-12-20
Also published as: CN102224717B; CN102224717A

Abstract

The embodiments of the invention disclose an activation method and apparatus for newly joined line pairs in an xDSL system. The method includes: according to the crosstalk offset coefficient among the line pairs at the data transmission stage and the number of the newly joined line pairs, constructing an initial pilot sequence; according to the initial pilot sequence, estimating the crosstalk offset coefficient of the newly joined line pairs to the line pairs at the data transmission stage; according to the crosstalk offset coefficient of the newly joined line pairs to the line pairs at the data transmission stage, constructing an augmented pilot sequence on the basis of the initial pilot sequence; according to the augmented pilot sequence, estimating the crosstalk offset coefficient of the line pairs at the data transmission stage to the newly joined line pairs; and activating the newly joined line pairs to be online and into the data transmission stage. The invention is used to activate the newly joined line pairs to be online in the xDSL system.

Description

Activation method and device for newly added pair in xDSL system, xDSL system

The present invention relates to the field of communications technologies, and in particular, to a method and apparatus for activating a newly added pair in an xDSL system, and an xDSL system. Background technique

xDSL is a general term for various types of DSL (Digital Subscribe Line). xDSL is a high-speed data transmission technology for transmission over telephone twisted pair. In addition to DSL for baseband transmission such as IDSL (ISDN-based digital subscriber line) and SHDSL (single-pair high-speed digital subscriber line), xDSL for passband transmission uses frequency division multiplexing technology to enable xDSL to coexist with traditional telephone service (POTS). On the same pair of twisted pairs, where xDSL occupies a high subcarrier, POTS occupies a baseband portion below 4 kHz, and the POTS signal and the xDSL signal are separated by a splitter. A device that provides multiple xDSL access is called a DSL Access Multiplexer (DSLAM).

Due to the principle of electromagnetic induction, the multiple signals connected by the DSLAM will interfere with each other, called crosstalk. Both near-end crosstalk (NEXT) and far-end crosstalk (FEXT) energy increase as subcarriers rise. The xDSL uplink and downlink channels use frequency division multiplexing, and near-end crosstalk (NEXT) does not cause much harm to the performance of the system. However, since the subcarriers used by xDSL are getting wider and wider, far-end crosstalk (FEXT) is more and more seriously affecting the transmission performance of the line. In xDSL transmission, crosstalk is reflected as part of the noise, so severe far-end crosstalk significantly reduces the channel rate. When multiple users in a bundle of cables are required to open xDSL services, some line rates are low, performance is unstable, or even impossible to open due to far-end crosstalk (FEXT), which ultimately results in a lower DSLAM outgoing rate.

At present, the main use of crosstalk cancellation (Vectored-DSL) technology, using the possibility of joint transmission and reception at the DSLAM end, the use of signal processing methods to offset the FEXT interference, and finally eliminate the FEXT interference in each signal.

In a Vectored-DSL system, the synchronization symbols are modulated and transmitted using a pilot sequence loop. For the uplink, the CO (Central Office) side resolves each subcarrier on the synchronization symbol. The transmitted signal is calculated and the error samples are calculated. For the downlink, the CPE (client device) side parses the signal transmitted on each subcarrier on the synchronization symbol and calculates an error sample, and then feeds the error sample back to C0. The CO side estimates the frequency domain transmission matrix or the uplink and downlink crosstalk cancellation coefficients on each subcarrier by using uplink and downlink error samples and known or parsed transmission signals.

When estimating the channel or crosstalk cancellation coefficients, it is necessary to use a pilot sequence of sufficient length. In actual use, the pilot sequences are generally orthogonal to make calculation of the channel or cancellation factor faster and easier. At the same time, in order to accurately estimate the channel or cancellation coefficient, the length of the pilot sequence is at least equal to the total number of newly added pairs in the current system and the total number of pairs in the transmission data phase (Showt ime). Therefore, in order to completely and accurately estimate the channel or cancellation coefficient between lines in the current system, at least the orthogonal pilot sequence with the length of all lines is required to modulate the synchronization symbol, that is, it is necessary to transmit a plurality of synchronization symbols of all lines.

In the process of implementing the present invention, the inventors have found that at least the following problems exist in the prior art: For a newly added pair, it is necessary to wait until the offset coefficient of the complete part is calculated before the bit bearer of each subcarrier can be calculated, and then enter the Showt ime stage. The crosstalk cancellation factor is estimated to be longer between all pairs, and the newly added pair needs to wait for a long time to activate the online. Summary of the invention

Embodiments of the present invention provide a method and apparatus for activating a newly added pair in an xDSL system, and an xDSL system, which can reduce the time for estimating the crosstalk cancellation coefficient between all pairs, thereby reducing the activation time of newly added pairs.

The technical solution adopted by the embodiment of the present invention is:

A method for activating a newly added pair in an xDSL system, comprising:

Constructing an initial pilot sequence according to the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs;

And estimating, according to the initial pilot sequence, a crosstalk cancellation coefficient of a new pair of pairs of pairs in a transmission data phase;

And according to the newly added pair, the crosstalk cancellation coefficient of the pair in the transmission data phase is Constructing an augmented pilot sequence based on the initial pilot sequence;

And estimating, according to the augmented pilot sequence, a crosstalk cancellation coefficient of a pair of newly added pairs in a transmission data phase;

The new join line pair is activated to go online to enter the transmission data phase.

A DSL access multiplexer includes:

An initial pilot sequence construction module, configured to construct an initial pilot sequence according to a crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs;

a channel estimation module, configured to estimate, according to the initial pilot sequence, a crosstalk cancellation coefficient of a newly added pair pair in a transmission data phase line pair;

An augmented pilot sequence constructing module, configured to construct a boosted pilot sequence based on the initial pilot sequence based on the crosstalk cancellation coefficient of the pair of transmission data phase pairs according to the newly added pair; the channel estimation a module, configured to estimate, according to the augmented pilot sequence, a crosstalk cancellation coefficient of a pair of newly added pairs in a transmission data phase;

The activation module is configured to activate the new joining pair to go online to enter the transmission data phase.

An xDSL system, including a client device CPE and a central office CO, wherein

The client device is configured to notify the central office of the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs;

The central office is configured to construct an initial pilot sequence according to the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs, and estimate the new pair of pairs according to the initial pilot sequence. a crosstalk cancellation coefficient in a transmission data phase line pair, constructing an augmented pilot sequence based on the initial pilot sequence based on the crosstalk cancellation coefficient of the pair of transmission data phase pairs, according to the The pilot sequence is augmented, and the crosstalk cancellation coefficient of the pair of newly added pairs in the transmission data phase is estimated, and the newly added pair is activated to go online to enter the transmission data phase.

In the embodiment of the present invention, a method and apparatus for newly adding a pair of lines and an xDSL system construct an initial pilot sequence according to the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs. And estimating the crosstalk of the newly added pair to the pair in the transmission data phase The cancellation coefficient, based on the estimated crosstalk cancellation coefficient, constructs an augmented pilot sequence based on the initial pilot sequence, and estimates a crosstalk cancellation coefficient of the pair of newly added pairs in the transmission data phase pair. Compared with the prior art, the embodiment of the present invention reduces the scale of the pilot sequence, and can reduce the time for estimating the crosstalk cancellation coefficient between all pairs, thereby reducing the activation time of the newly added pair. DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments or the prior art description will be briefly described below. It is obvious that the drawings in the following description are only the present invention. For some embodiments, other drawings may be obtained from those of ordinary skill in the art without departing from the drawings.

1 is a flowchart of a method according to Embodiment 1 of the present invention;

2 is a flowchart of a method according to Embodiment 2 of the present invention;

3 is a schematic diagram of a channel matrix between a pair of transmission data phase pairs and all pairs of the newly added line pair in the second embodiment of the present invention;

4 is a flowchart of a method according to Embodiment 3 of the present invention;

5 and FIG. 6 are schematic structural diagrams of a DSL access multiplexer according to Embodiment 4 of the present invention;

FIG. 7 is a schematic structural diagram of an xDSL system according to Embodiment 5 of the present invention. detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

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

Embodiment 1

This embodiment provides a method for activating a newly added pair in an xDSL system. As shown in FIG. 1, the method includes: 1 01. The DSLAM (DSL Access Multiplexer) constructs an initial pilot sequence based on the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs.

01. The DSLAM estimates, according to the initial pilot sequence, a crosstalk cancellation coefficient of the newly added pair pair in the transmission data phase line pair.

1 . The DSLAM constructs an augmented pilot sequence based on the initial pilot sequence according to the crosstalk cancellation coefficient of the pair of transmission data phase pairs.

104. The DSLAM estimates the crosstalk cancellation coefficient of the pair of newly added pairs in the transmission data phase according to the augmented pilot sequence.

1 05. The DSLAM activates the new join line pair to enter the transmission data phase.

In the embodiment of the present invention, the activation method of the newly added pair in the xDSL system, the DSLAM constructs an initial pilot sequence according to the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs, and estimates the new joining line. Constructing an augmented pilot sequence based on the estimated pilot crosstalk cancellation coefficient based on the estimated crosstalk cancellation coefficient on the basis of the initial pilot sequence, and estimating the line pair pair new joining line in the transmission data phase The crosstalk cancellation factor of the pair. Compared with the prior art, the embodiment of the present invention reduces the scale of the pilot sequence, and can reduce the time for estimating the crosstalk cancellation coefficient between all pairs, thereby reducing the activation time of the newly added pair.

Embodiment 2

This embodiment provides a method for activating a newly added pair in an xDSL system. In this embodiment, in the Vec tored-DSL system, by analyzing the crosstalk cancellation coefficient between line pairs currently in the transmission data phase, the current All strong and weak relationships between the pairs of lines in the transmission data phase. Through the strong and weak relationship, the line pairs in the transmission data phase may be explicitly or implicitly merged into multiple groups, that is, the pair of lines in the group have a serious crosstalk, and any two pairs are not in the same group. The crosstalk between the lines is weak or almost ineffective.

On the other hand, through the configuration of the Vec tored-DSL management system, it is also possible to configure the line pairs currently in the transmission data phase, and merge all or part of the line pairs into one or more groups explicitly or implicitly. Wherein, the displayed merged into multiple groups refers to the actual grouping of the pair in the transmission phase, and then respectively analyzing and processing the crosstalk cancellation coefficients of the pairs in each group, and the groups obtained here are For the group to be displayed; and implicitly merged into multiple groups, it means that the pair of lines in the transmission phase are not actually grouped, but the crosstalk cancellation coefficient is analyzed and processed, and multiple pairs are put together. Performing, a plurality of pairs of pairs of crosstalk canceling coefficients analyzed and processed together constitute an implicit group.

For ease of description, all of the embodiments described below are described using explicit groups.

In the Vectored-DSL system, in the transmission data phase, the pair has A packets, which are respectively denoted as _gi , and the number of pairs in the group is / _; , i = ····, !(·, and the newly added pair is recorded as The total number of pairs is; in this embodiment, the crosstalk between the groups is quite small and can be ignored.

As shown in FIG. 2, the method includes:

201. The DSLAM constructs an initial pilot sequence according to the current packet that is already in the transmission data phase (showtime) pair and the number of new join-in pairs.

First, write J^/ max/,., select any positive integer J greater than or equal to J*, and generate JxJ ( J

\≤i≤k

The matrix M of row J), MM ^H = cI , where c is a positive real number, M ^ff represents the conjugate transpose of M, and / is the identity matrix. Obviously, for any complex number · + · , satisfied.Μ

酉 matrix, ie

Then, the Γ line of the matrix M is arbitrarily selected as the pilot sequence of each pair of line pairs in the newly added pair, and the sub-matrix formed by the Γ line is ^.

Then, from the remaining J-Γ lines of the matrix M, the rows are arbitrarily selected as the initial pilot sequences of the existing paired pairs. The submatrix formed by the corresponding row is i = \ ",k.

As shown in Figure 3, in the current system, there are two groups in the transmission data phase line pair, respectively _gl , g ₂ , each with 4 line pairs; newly added line pair group X, a total of 2 line pairs; , G ₂ is the matrix of the crosstalk cancellation coefficient between the pairs in the two groups; B, respectively, the pair of new pairs is in the transmission data The crosstalk cancellation coefficient matrix of the phase line pair, and the matrix element is unknown, and needs to be calculated by channel training; 4, ^ respectively is the crosstalk cancellation coefficient matrix of the pair of newly added pairs in the transmission data phase, and the matrix element is unknown, It needs to be calculated through channel training; it is the crosstalk cancellation coefficient matrix between the pair pairs within the new pair. The new pilot sequence is a matrix M of J rows and J columns, and satisfies MM ^ff =c./, where c is a positive real number, and any two rows in the distribution matrix M are given to the X pairs of the new uplink, which will be removed. Allocated 2 rows of matrix M, select any 4 rows assigned to & group, and select any 4 #分西己^& group. More than 3⁄4 口#3⁄4 口下西己:

L* = ί + max 1=2 + max{4, 4} = 6 Use the following matrix rows as the pilot sequence for each pair:

At this time, the assigned pilots of the newly added pair are respectively the 2nd row and the 3rd row of the above matrix:

In the transmission data phase line, the first row and the second group are respectively assigned the fourth row of the above matrix, the seventh row:

1 -1 -1 1 1 -1 -1 1

Group pair 1 group pair 1

1 1 1 1 -1 -1 -1 -1

Group pair 2 group pair 2

1 -1 1 -1 -1 1 -1 1

Group line pair 3 Group line pair 3

1 1 -1 -1 -1 -1 1 1

Group pair 4

The pair of lines 4 and , where the number is positive and negative 1 to the bit sequence of the pilot sequence, bit 0 is mapped as follows:

Therefore, the pilots of the newly added lines are:

The pilots in the transmission data phase line pair of the first group and the second group are respectively:

202. The DSLAM modulates the synchronization symbol according to the initial pilot sequence, obtains an error sample, and estimates, according to the error sample, a crosstalk cancellation coefficient of the pair of pairs in the transmission data phase and a crosstalk between the newly added pairs. The cancellation factor, or only the crosstalk cancellation factor of the newly added pair pair in the transmitted data phase pair.

All pairs are modulated with the initial pilot sequence of the same length (J) assigned by step 202, and the feedback error samples are used to estimate the pair of pairs in the transmission data phase. And the crosstalk between the newly added pairs, and the crosstalk cancellation coefficient of A, B ₂ shown in Fig. 3 is estimated. Specifically, the crosstalk cancellation coefficient can be estimated by:

Since the crosstalk between groups is quite small and can be ignored, the product of FEQ and the actual channel matrix is approximated by using frequency domain equalization (FEQ):

Where Η _ϋ =Ι + Ο _ϋ , X = I + 0, O,. and O are all diagonal.

According to step 201, & will use the initial pilot sequence to modulate the sync symbols, and the initial pilot sequence S* will be used to modulate the sync symbols.

In the Vectored-DSL system, bit 0 in the pilot sequence represents all subcarrier modulations of the synchronization symbol all zeros, that is, modulating 00 on all subcarriers to transmit the constellation point 1+i in the 4-QAM constellation. Bit 1 in the frequency sequence represents all subcarrier modulations of the sync symbol all 1s, i.e., modulation 11 on all subcarriers to transmit the constellation point -li in the 4-QAM constellation. In the Vector system, a row of a matrix composed of positive and negative 1 is generally used as a pilot sequence, and the following correspondence is used:

+1→ bit 0→ bit 00→ 4-QAM Constellation Point 1 + /

-1→ bit 1→ bit 11→ 4-QAM Constellation Point - (1 + /) or

— 1→ bit 0→ bit 00→ 4-QAM Constellation Point 1 + /

+1→ bit 1→ bit 11→ 4-QAM Constellation Point - (1 + /) On the other hand, each subcarrier uses a scrambling code to rotate the transmitted constellation points. The function of the scrambling code is to rotate the constellation points 0, 90, 180, 270 degrees, equivalent to multiplying the original constellation points by 1, i, -1, _i. Here, the amplitude of the rotated constellation points is adjusted for transmission, so that the transmitted constellation points can always be expressed as plus or minus 1 times a complex number.

Any one of the subcarriers of all the subcarriers of the initial pilot sequence is assumed. If the complex number of the subcarrier is multiplied by t, the error samples obtained by the feedback are (ignoring the influence of noise and quantization error): "" 0 · ·· 0 ΒΛ

0 ₂₂ · ·· 0 B ₂ s ₂

E = H- ■t- ■t = t- s _k s _k 0 0 · ·· _kk B _k s _k

, 4 · ·· )

Since MM ^ff =c'I , where c is a positive real number, therefore:

, ^ff =0

s^is =0

Wherein, the order matrix is the order; the other elements except the diagonal element is 1 are 0; /, the unit matrix whose order is /, S,. (the result of f =0 is the line /, the zero matrix of the column

(Elements are 0), use 0 to represent the zero matrix. Thus there are:

Therefore, by calculating £. .(^ S ... S (S*f)], we can estimate . and O because the frequency domain channel matrix of the Vectored-DSL system is generally strong diagonally dominant, therefore, the new addition The crosstalk cancellation coefficient of the pair of pairs in the transmission data phase is approximately equal to - . The crosstalk cancellation coefficient between the newly added pairs is approximately equal to /-O.

203. The DSLAM pairs the crosstalk cancellation coefficient in the transmission data phase pair and the crosstalk cancellation coefficient between the newly added pair according to the newly added pair, or only according to the new joining pair in the transmission data phase pair. The crosstalk cancellation coefficient is re-grouped for the newly added pair and the data phase in the transmission data phase.

Performing amplitude or other analysis on the crosstalk cancellation coefficients in the transmission data phase pair and the newly added pair on the newly added pair, or by using the crosstalk cancellation coefficient in the transmission data phase pair for the newly added pair The magnitude or other analysis will be added to the group of pairs, and the existing group A & regroup. The result of regrouping is that with w, & w, &, / = 1, ···, 成为 becomes a new group, the other groups are unchanged. Record the w groups as (3⁄4, i = l, ---, w (which is one of &). As shown in Figure 3, there may be three cases:

Case 1: w = 0, X is a group;

Case 2: w = \ , X and & or & become a group;

Case 3: w≥2, X and & and & become a group.

204. The DSLAM constructs an augmented pilot sequence based on the initial pilot sequence according to the result of the regrouping.

When the result of the regrouping is case 1: w = 0, then the groups are independently grouped, and the string 4 in the group is calculated in step 202.

When the result of the regrouping is case 2: w = l, at this time, one of the 7 _{; is} merged into a group (3⁄4, the error sample obtained by the J-length pilot sequence used in step 202 can be transmitted in the middle The crosstalk cancellation coefficient of the new pair of pairs in the phase line pair is calculated.

When the result of the regrouping is Case 3: w ≥ 2, the w groups are respectively recorded as i = l, ---, w, and the pilot sequences of the J lengths used by the w groups in step 202 are respectively For: / = 1,···, /.

Randomly selecting one number greater than or equal to _[mu] ^, generator matrix rows beta] ¾ ¾ columns, and satisfies: The elements of the first column of ρ are all 1, 3.QQ ^H = uI;

·0 is the unitary matrix, ie the vector r, the first of r

The elements are 1, J .r ^ff =w.

Select w lines from ρ and write them as / , Ι,···,Μ/.

The new pilot sequence assigned to group 0i is:

§; =q _i (2:u)®S _i

Where (2: ί) is the sub-vector of the second to last column of the row vector; x®_y represents the Kronecker product of X and ;

Assign a new pilot sequence to the group ^ is:

S" =r(2: )®S"

Sending with the newly allocated pilot sequence and receiving the error samples, and combining the pilot sequences allocated by the w + 1 groups in step 201 and the corresponding error samples, can calculate the pair of pairs in the transmission data phase. The crosstalk cancellation factor of the newly added pair and the crosstalk cancellation coefficient between the newly added pairs.

In conjunction with step 201, and considering that the elements of the first column of β are all 1, the union of the pilot sequences used in the two steps is equivalent to assigning the following augmented pilot sequences to w:

Using the Augmented pilot sequence, the integrated error samples acquired in step 202, a crosstalk cancellation coefficient can be calculated internal to the newly added line in the _w in the data transmission phase line.

205. The DSLAM estimates, according to the augmented pilot sequence and the error sample, a crosstalk cancellation coefficient between a pair of newly added pairs in a transmission data phase pair and/or a crosstalk cancellation between newly added pairs. Coefficient.

The channel and crosstalk cancellation coefficients can be estimated as follows:

The case of case 1 and case 2 in step 203 is not repeated here, and only case 3: w≥2 is considered here.

At this point, after grouping, the newly added pair is combined with , / = 1, ···, ^ to form a new group, because _; , that is, O has been estimated in step 202, so that only (3⁄4, / = 1, need to be estimated again) ···, / related 4

According to step 204, the pair of pairs (3⁄4, / = 1, . . . , / the transmitted signal and the signal transmitted in step 202 will form the following matrix:

Where, is the row of the matrix β, and β·β ^Η = u thus

m -- = u

Ml - =0,

Therefore, the following formula is satisfied:

U® c- l) = uc- 1 q _i ®§i, person _qj ®§ q _i ®S _i (qf ®S _j ^H ) = (q _i q^)®(S _i S

Iq r ^H )®0 = 0

(r®^ =^3⁄4®^)-(r®^ jj =0" =0

Thus available:

SS ^H =u'c'I

Therefore, for the pair of lines (3⁄4, i = l, ---, w , combine the error samples in step 202:

Have:

Thus, by calculation, you can <E(t f , you can completely estimate (3⁄4, i = \, -, w, the corresponding 4, i = \, ---, w, and O.

Since the frequency domain channel matrix of the Vectored-DSL system is generally dominated by strong diagonals, the crosstalk cancellation coefficient of the pair of newly added pairs in the transmission data phase is approximately equal to -. The crosstalk cancellation factor between the newly added pairs is approximately equal to /-O.

206. The DSLAM activates the newly added pair to go online to enter the transmission data phase.

At this point, the crosstalk cancellation coefficient between all pairs is estimated to be completed, and the newly added pair is activated. In the xDSL system of the embodiment of the present invention, the DSL AM constructs an initial pilot sequence according to the number of packets currently in the transmission data phase pair and the number of newly added pairs, and estimates the newly added pair. The crosstalk cancellation coefficient between the pair of lines in the transmission data phase and the crosstalk cancellation coefficient between the newly added pair, or only the crosstalk cancellation coefficient of the pair of pairs in the transmission data phase of the newly added pair, based on the estimated crosstalk cancellation coefficient Regrouping the newly added pair and the data phase in the transmission data phase, constructing an augmented pilot sequence based on the initial pilot sequence, and estimating the line pair in the transmission data phase according to the result of the regrouping Crosstalk cancellation for newly added pairs Coefficient, or continue to estimate the crosstalk cancellation factor of the newly added pair pair in the transmitted data phase pair. Compared with the prior art, the embodiment of the present invention reduces the scale of the pilot sequence, can reduce the time for estimating the crosstalk cancellation coefficient between all pairs, thereby reducing the activation time of the newly added pair; When the crosstalk cancellation coefficient of the newly added pair is added and/or the new pair of pairs is paired with the crosstalk cancellation coefficient of the pair in the transmission data phase, the pilot sequence of the pair of pairs in the transmission data phase can be multiplexed, thereby The time to estimate the crosstalk cancellation coefficient between all pairs can be further shortened.

Embodiment 3

This embodiment provides a method for activating a newly added pair in an xDSL system. The difference from the second embodiment is that, in this embodiment, the pilot sequence used in step 201 in the second embodiment and the new matrix used in step 204 are used. ρ is optimized. Use a special Wa l sh matrix with a power of 2 (a special case of the Hadama rd matrix) for assigning pilot sequences and as Q.

Wherein, the Wa 1 sh matrix is constructed as follows:

Where ® represents the kronecke r product, N is the set of natural numbers, and 2 ≤ A e N is expressed as A taking all natural numbers greater than or equal to 2. The Wa l sh matrix satisfies:

As shown in FIG. 4, the method includes:

401. The DSLAM performs explicit or implicit pre-packet processing on the packet currently in the transmission data phase pair.

As in the second embodiment, the packet described herein is based on the crosstalk cancellation coefficient between the current transmission data phase pairs, or through the Vec t ored-DSL management layer configuration. The pre-packet processing described herein is to implicitly or explicitly perform the implicit or explicit packet according to a predetermined rule. Merger. For convenience of description, an explicit description is used for the pre-grouping below.

The current packet is preprocessed when the system line pair is online. The purpose of the pre-processing is to merge the current K groups according to certain rules to reduce the time for the new join pair to activate.

Find a non-negative integer p≥0, and re-group the existing group &, i = \,...,k in the system into 2 groups i = l,--,2 ^p , the number of pairs in the group For _; Satisfy:

Where is the union of one or more &, and the disjoint, the union of which is equal to the union of &. Capable of covering the size of the Walsh matrix with the most lines, equal to covering all pairs

The size of the Wa 1 sh matrix (including newly added pairs), namely:

Preferably, the largest and corresponding merged existing grouping schemes satisfying the above conditions are found.

402. The DSLAM constructs an initial pilot sequence according to the explicit or implicit grouping of the explicit or implicit pre-packet processing and the number of newly added pairs, which are currently in the transmission data phase line pair.

First select the group with the largest number of pairs, the number of pairs of the group; add the logarithm of the new join line /* to generate a Walsh head macro array of 2 ¹ ' ¹ scale (2 ¹ ' ¹ line 2 ¹ '¹歹'J);

Then, the /* line in the Walsh matrix is arbitrarily assigned to the initial pilot sequence S* as the initial row in the Walsh matrix; the row is given as the initial pilot sequence. Each pair in the Gi group is guaranteed to use a different row, and the same row of the Wa 1 s h matrix can be used between the different groups.

403. The DSLAM is in the initial pilot sequence, and the crosstalk cancellation coefficient of the newly added pair pair in the transmission data phase pair and the crosstalk cancellation coefficient between the newly added pair are estimated, or only the newly added pair pair is estimated to be in transmission. The crosstalk cancellation factor of the data phase pair.

All pairs of pairs use the initial pilot sequence of the same length ( ₂ "°^+"^')1) assigned in step 403 to modulate the synchronization symbol, and estimate the new pair of pairs to be in the transmission data stage through the feedback error samples. The pair of lines, and the crosstalk cancellation factor between the newly added pairs.

The calculation of this step is similar to the step 202 in the second embodiment, and details are not described herein again.

404. The DSLAM pairs the crosstalk cancellation coefficient in the transmission data phase pair according to the new joining pair, and the crosstalk cancellation coefficient between the newly added pair, or only according to the new joining pair in the transmission data phase pair. The crosstalk cancellation coefficient is re-grouped for the newly added pair and the data phase in the transmission data phase.

Performing amplitude or other analysis on the crosstalk cancellation coefficients in the transmission data phase pair and the newly added pair on the newly added pair, or by using the crosstalk cancellation coefficient in the transmission data phase pair for the newly added pair For amplitude or other analysis, the group of newly added pairs is merged into the pre-processed 2 groups / = 1, . . . , 2 . The result of regrouping is that w in /1, .., 2 becomes a new group, and the others are unchanged. There may be three cases:

Case 1: w = 0, in this case, stand alone;

Case 2: w = \ , at this point merge with one of all ^ into one group;

Case 3: w≥2, at this time with all 7 _; ^^ is (5,., i = l, ---, w, merge into a group.

405. The DSLAM constructs an augmented pilot sequence based on the initial pilot sequence according to the result of the regrouping.

For case 1: w = 0, then the groups are independent, and the crosstalk cancellation coefficient in the group is calculated in step 403.

For case 2: w = \, then merge with one of them ^ to form a set of error samples obtained by the J-length pilot sequence used in step 403 to calculate the crosstalk cancellation coefficient.

For case 3: w ≥ 2, respectively, the w is (5, . , i = l, ---, w , and the pilot sequences of the J length used by the _w groups in step 403 are: i = \,-,w ₀

make:

Generates a _3⁄4 order 3⁄4^131 matrix ρ, where "χ" represents the smallest integer greater than or equal to X. Any from ρ Select the w line, divide the other ^one as / = ι,···,^.

New pilot sequence assigned to the group;

§; =q _i (2:u)®S _i

Where (2 _: w) is the sub-vector of the second to last column of the row vector; x®_y represents the Kronecker product of X and ;

Also assign a new pilot sequence to the group ^:

S* = (1, ···, 1)®S*

,

1χ(«- 1)

Transmitting with the new assigned pilot sequence and receiving the error samples, combined with the pilot sequence assigned by the w + 1 groups in step 302 and the corresponding error samples, can calculate all the pairs in the transmission data phase The crosstalk cancellation coefficient of the pair of newly added pairs, and the crosstalk cancellation coefficient between the newly added pairs.

Combining step 402 is equivalent to assigning the following augmented pilot sequences to w:

406. The DSLAM estimates, according to the augmented pilot sequence, a crosstalk cancellation coefficient between the pair of newly added pairs in the transmission data phase pair and/or a crosstalk cancellation coefficient between the newly added pairs.

Using the Augmented pilot sequence, the steps 403 acquires the error samples, _w can be computed in one stage in the data transmission line crosstalk cancellation coefficients on the inner newly added line.

The calculation of this step is similar to the step 205 in the second embodiment, and details are not described herein again.

407. The DSLAM performs re-grouping on the re-grouped new join pair and the transmit data phase pair.

In step 401, a pre-grouping process is performed. After steps 402-406, _w and _w are merged into one group. At this time, as for a part of the group, the grouping algorithm is used to obtain the obtained w and w. The union of 0i is used as a large group and regrouped.

408. The DSLAM activates the newly added pair to go online to enter the transmission data phase.

At this point, the crosstalk cancellation coefficient between all pairs is estimated to be completed, and the newly added pair is activated. It should be noted that, in this embodiment, step 401 and step 408 are optional steps.

For example: There are 200 pairs in the current Vec t or ed-DSL system, which have been divided into 4 groups, each group

With 50 pairs, there is now 1 new pair to activate. If a Wa l sh matrix with powers of 2 (both rows and columns are powers of 2) is used as the initial pilot sequence, its scale is:

2, ₌₂₅₆

The total transmission time of the required sync symbols is:

-x(256 + l)x256 = 16.4608 (s)

4000

Using the method described in this embodiment, the size of the complete pilot sequence is as follows:

In the actual scenario, the situation of w=l and w=2 usually occurs. Therefore, with the method provided in this embodiment, the activation time of the newly added pair can be significantly reduced.

In the xDSL system of the embodiment of the present invention, the DSL AM pre-groups the packets currently in the transmission data phase pair, according to the current pair of packets in the transmission data phase and the number of newly added pairs. Constructing an initial pilot sequence, and estimating a crosstalk cancellation coefficient of the newly added pair pair in the transmission data phase pair, and a crosstalk cancellation coefficient between the newly added pair, or estimating only the newly added pair pair in the transmission data phase line a pair of crosstalk cancellation coefficients, according to the estimated crosstalk cancellation coefficient, regrouping the newly added pair and the line pair in the transmission data phase, Constructing an augmented pilot sequence based on the initial pilot sequence and estimating a crosstalk cancellation coefficient of the pair of newly added pairs in the transmission data phase, or continuing to estimate that the newly added pair is in the pair according to the result of the regrouping The crosstalk cancellation coefficient of the data phase line pair is transmitted, and the re-grouped new join line pair and the transmission data phase line pair are regrouped. Compared with the prior art, the embodiment of the present invention reduces the scale of the pilot sequence, can reduce the time for estimating the crosstalk cancellation coefficient between all pairs, thereby reducing the activation time of the newly added pair; For the crosstalk cancellation coefficient of the newly added pair, the pilot sequence of the pair of pairs in the transmission data phase can be multiplexed, so that the time for estimating the crosstalk cancellation coefficient between all pairs can be further shortened; The packet processing and the re-packet processing can further reduce the time for the new join pair to activate.

Embodiment 4

This embodiment provides a DSL access multiplexer. As shown in FIG. 5, the DSL access multiplexer includes: an initial pilot sequence construction module 51, configured to be used according to a line pair currently in a transmission data phase. Constructing an initial pilot sequence by the crosstalk cancellation coefficient and the number of newly added pairs;

The channel estimation module 52 is configured to estimate, according to the initial pilot sequence, a crosstalk cancellation coefficient of a pair of newly added pairs of pairs in a transmission data phase, and a crosstalk cancellation coefficient between newly added pairs, or only estimate a new joining line a crosstalk cancellation coefficient for a pair of lines in the transmission data phase;

The augmented pilot sequence construction module 53 is configured to construct, according to the newly added pair, a crosstalk cancellation coefficient in a transmission data phase line pair, constructing an augmented pilot sequence on the basis of the initial pilot sequence; The estimating module 52 is further configured to: according to the augmented pilot sequence, estimate a crosstalk cancellation coefficient of a pair of newly added pairs in a transmission data phase;

The activation module 54 is configured to activate the new joining pair to go online to enter the transmission data phase.

Further, the channel estimation module 52 is further configured to estimate, according to the initial pilot sequence, a crosstalk cancellation coefficient between newly added pairs;

The augmented pilot sequence construction module 53 is further configured to: according to the newly added pair, a crosstalk cancellation coefficient of a pair of lines in the transmission data phase, and a crosstalk cancellation coefficient between the newly added pairs, Constructing an augmented pilot sequence based on the initial pilot sequence;

The channel estimation module 52 is further configured to estimate, according to the augmented pilot sequence, a crosstalk cancellation coefficient between a pair of newly added pairs in a transmission data phase pair and/or a crosstalk cancellation coefficient between the newly added pairs.

Further, as shown in FIG. 6, the augmented pilot sequence construction module 53 includes:

Re-grouping unit 531, configured to re-group the new joining pair and the data phase in the transmission data phase;

The constructing unit 532 is configured to construct an augmented pilot sequence based on the initial pilot sequence according to the result of the regrouping.

Further, as shown in FIG. 6, the DSL access multiplexer may further include:

The pre-packet processing module 55 is configured to perform pre-group processing on the packets currently in the transmission data phase pair.

Further, as shown in FIG. 6, the DSL access multiplexer may further include:

The re-packet processing module 56 is configured to perform re-grouping processing on the re-grouped new joining pair and the transmitting data phase pair.

Further, the initial pilot sequence construction module 51 is configured to construct an orthogonal matrix of the initial pilot sequence according to the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs. And the new join line pair separately occupies a partial row of the orthogonal matrix, and the remaining rows of the orthogonal matrix are multiplexed between packets currently in the transmission data phase line pair and are not repeated within the packet.

Further, the channel estimation module 52 is specifically configured to: modulate a synchronization symbol according to the initial pilot sequence, obtain an error sample, and estimate, according to the error sample, a crosstalk cancellation coefficient of a pair of pairs in the transmission data phase according to the error sample. .

Further, the channel estimation module 52 is further configured to estimate, according to the augmented pilot sequence and the error sample, a crosstalk cancellation coefficient of a pair of newly added pairs in a transmission data phase.

In the embodiment of the present invention, the DSL access multiplexer performs the packet currently in the transmission data phase pair. Pre-packet processing, constructing an initial pilot sequence according to the number of packets currently in the transmission data phase pair and the number of newly added pairs, and estimating the crosstalk cancellation coefficient of the newly added pair pair in the transmission data phase pair, and newly joining The crosstalk cancellation coefficient between the pair, or only the crosstalk cancellation coefficient of the newly added pair pair in the transmission data phase pair, based on the estimated crosstalk cancellation coefficient, the pair of newly added pairs and the line in the transmission data phase Performing re-grouping, constructing an augmented pilot sequence based on the initial pilot sequence, and estimating a crosstalk cancellation coefficient of the pair of newly added pairs in the transmission data phase, or continuing to estimate the new join. The pair is paired with the crosstalk cancellation coefficient in the transmission data phase pair, and the re-grouped new joined pair and the transmitted data phase pair are regrouped. Compared with the prior art, the embodiment of the present invention reduces the scale of the pilot sequence, can reduce the time for estimating the crosstalk cancellation coefficient between all pairs, thereby reducing the activation time of the newly added pair; For the crosstalk cancellation coefficient of the newly added pair, the pilot sequence of the pair of pairs in the transmission data phase can be multiplexed, so that the time for estimating the crosstalk cancellation coefficient between all pairs can be further shortened; The packet processing and the re-packet processing can further reduce the time for the new join pair to activate.

Embodiment 5

This embodiment provides an xDSL system. As shown in FIG. 7, the xDSL system includes a client device (CPE) 71 and a central office (CO) 72, where

The client device 71 is configured to notify the central office 72 of the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs;

The central office 72 is configured to construct an initial pilot sequence according to the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs, and estimate the newly added pair according to the initial pilot sequence. Constructing an augmented pilot sequence on the basis of the initial pilot sequence, based on the crosstalk cancellation coefficient of the pair of lines in the transmission data phase, based on the crosstalk cancellation coefficient of the pair of pairs in the transmission data phase, according to the initial pilot sequence The augmented pilot sequence is estimated, and the crosstalk cancellation coefficient of the pair of newly added pairs in the transmission data phase is estimated, and the newly added pair is activated to go online to enter the transmission data phase.

Further, the central office 72 is further configured to estimate a new join according to the initial pilot sequence. a crosstalk cancellation coefficient between the pair, a crosstalk cancellation coefficient of the pair in the transmission data phase according to the newly added pair, and a crosstalk cancellation coefficient between the newly added pairs, based on the initial pilot sequence Constructing an augmented pilot sequence, estimating a crosstalk cancellation coefficient between the pair of newly added pairs and/or a crosstalk cancellation coefficient between the newly added pairs based on the augmented pilot sequence.

Further, the central office 72 is further configured to re-group the newly added pair and the data phase in the transmission data phase, and construct an augmentation guide based on the initial pilot sequence according to the result of the regrouping. Frequency sequence.

Further, the central office 72 is further configured to perform pre-packet processing on the packets currently in the transmission data phase pair.

Further, the central office 72 is further configured to perform re-grouping processing on the re-grouped new joining pair and the transmitting data phase pair.

In the xDSL system of the embodiment of the present invention, the central office performs pre-packet processing on the packets currently in the transmission data phase pair, constructs an initial pilot sequence according to the number of packets currently in the transmission data phase pair and the number of newly added pairs, and Estimating the crosstalk cancellation coefficient of the pair of pairs in the transmission data phase and the crosstalk cancellation coefficient between the newly added pair, or estimating only the crosstalk cancellation coefficient of the pair of pairs in the transmission data phase of the newly added pair, according to the estimation a crosstalk cancellation coefficient, re-grouping the newly added pair and the data phase in the transmission data phase, constructing an augmented pilot sequence based on the initial pilot sequence according to the result of the regrouping, and estimating Transmitting the data phase line pair to the crosstalk cancellation coefficient of the newly added pair, or continuing to estimate the crosstalk cancellation coefficient of the newly added pair pair in the transmission data phase pair, and retransmitting the newly added pair and transmitting data The phase line pairs are grouped again. Compared with the prior art, the embodiment of the present invention reduces the scale of the pilot sequence, can reduce the time for estimating the crosstalk cancellation coefficient between all pairs, thereby reducing the activation time of the newly added pair; For the crosstalk cancellation coefficient of the newly added pair, the pilot sequence of the pair of pairs in the transmission data phase can be multiplexed, so that the time for estimating the crosstalk cancellation coefficient between all pairs can be further shortened; The packet processing and the re-packet processing can further reduce the time for the new join pair to activate. The DSL access multiplexer and the xDSL system provided by the embodiments of the present invention may implement the foregoing method embodiments. For the specific function implementation, refer to the description in the method embodiment, and details are not described herein again. The activation method, the DSL access multiplexer, and the xDSL system of the newly added pair in the xDSL system provided by the embodiment of the present invention may be applicable to the activation of the newly added pair in the xDSL system, but is not limited thereto.

A person skilled in the art can understand that all or part of the process of implementing the above embodiment method can be completed by a computer program to instruct related hardware, and the program can be stored in a computer readable storage medium. In execution, the flow of an embodiment of the methods as described above may be included. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

The above is only the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any change or replacement that can be easily conceived by those skilled in the art within the technical scope of the present invention is All should be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

Claim

A method for activating a newly added pair in an xDSL system, comprising: a number, constructing an initial pilot sequence;

And estimating, according to the initial pilot sequence, a crosstalk cancellation coefficient of a newly added pair pair in a transmission data phase line pair;

Constructing an augmented pilot sequence on the basis of the initial pilot sequence according to the crosstalk cancellation coefficient of the pair of transmission data phase pairs according to the newly added pair;

2. The method according to claim 1, wherein the method further comprises:

Estimating a crosstalk cancellation coefficient between newly added pairs according to the initial pilot sequence;

And constructing an augmented pilot sequence on the basis of the initial pilot sequence according to the crosstalk cancellation coefficient of the pair of transmission data phase pairs and the crosstalk cancellation coefficient between the newly added pairs; The augmented pilot sequence is estimated to estimate the crosstalk cancellation coefficient between the pair of newly added pairs in the transmission data phase pair and/or the crosstalk cancellation coefficient between the newly added pairs.

The method according to claim 1, wherein the constructing the augmented pilot sequence on the basis of the initial pilot sequence comprises:

Regrouping the newly added pair and the line pair in the transmission data phase;

Based on the result of the regrouping, an augmented pilot sequence is constructed based on the initial pilot sequence.

The method according to claim 3, further comprising: before constructing the initial pilot sequence according to the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs, :

5. The method according to claim 4, wherein said new joining line is excited Before the live line enters the transmission data phase, it also includes:

The newly added pairs and the data pairs in the transmission data phase are regrouped.

The method according to claim 1, wherein the initial pilot sequence is configured according to the crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and the number of newly added pairs, including: number, construction An orthogonal matrix of initial pilot sequences, wherein the newly added pair of lines independently occupy a partial row of the orthogonal matrix, and the remaining rows of the orthogonal matrix are multiplexed between packets currently in a transmission data phase pair And not repeated within the packet.

The method according to claim 1, wherein, according to the initial pilot sequence, estimating a crosstalk cancellation coefficient of a newly added pair pair in a transmission data phase line pair includes:

Acquiring a synchronization symbol according to the initial pilot sequence to obtain an error sample;

Based on the error samples, the crosstalk cancellation coefficients of the newly added pair pair in the transmission data phase pair are estimated.

The method according to claim 7, wherein, according to the augmented pilot sequence, estimating a crosstalk cancellation coefficient of a pair of newly added pairs in a transmission data phase line pair includes:

Based on the augmented pilot sequence and the error samples, the crosstalk cancellation coefficients of the pair of newly added pairs in the transmitted data phase are estimated.

9. A DSL access multiplexer, comprising:

An initial pilot sequence construction module, configured to construct an initial pilot sequence according to a crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and a number of newly added pairs;

An augmented pilot sequence construction module, configured to construct a augmented pilot sequence based on the initial pilot sequence based on the crosstalk cancellation coefficient of the pair of transmission data phase pairs according to the newly added pair;

The channel estimation module is further configured to estimate, according to the augmented pilot sequence, that the data is in a transmission order The crosstalk cancellation coefficient of the pair of new pairs added to the pair;

The DSL access multiplexer according to claim 9, wherein the channel estimation module is further configured to estimate a crosstalk cancellation coefficient between newly added pairs according to the initial pilot sequence; The augmented pilot sequence construction module is further configured to: according to the new joining pair, a crosstalk cancellation coefficient in a pair of transmission data phase pairs, and a crosstalk cancellation coefficient between newly added pairs, in the initial pilot sequence Constructing an augmented pilot sequence based on;

The channel estimation module is further configured to estimate, according to the augmented pilot sequence, a crosstalk cancellation coefficient between a pair of newly added pairs of transmission data phase pairs and/or a crosstalk cancellation coefficient between the newly added pairs.

The DSL access multiplexer according to claim 9, wherein the augmented pilot sequence construction module comprises:

a regrouping unit, configured to regroup the new joining pair and the data phase in the transmission data phase;

And a constructing unit, configured to construct an augmented pilot sequence based on the initial pilot sequence according to the result of the regrouping.

The DSL access multiplexer according to claim 11, further comprising: a pre-packet processing module, configured to perform pre-group processing on the packets currently in the transmission data phase pair.

The DSL access multiplexer according to claim 12, further comprising: a re-packet processing module, configured to perform the re-grouping of the newly added pair and the line pair in the transmission data phase Group processing again.

The DSL access multiplexer according to claim 9, wherein the initial pilot sequence construction module is specifically configured to use a crosstalk cancellation coefficient between the pair of lines currently in the transmission data phase and a new join line. Constructing an orthogonal matrix of the initial pilot sequence, wherein the newly added pair of lines independently occupy part of the orthogonal matrix, and the remaining rows of the orthogonal matrix are currently in the transmission data phase pair The packets are multiplexed between each other and are not repeated within the packet.

The DSL access multiplexer according to claim 9, wherein the channel estimation module is configured to: modulate a synchronization symbol according to the initial pilot sequence, and acquire an error sample, according to the error sample, It is estimated that the newly added pair is the crosstalk cancellation coefficient of the pair in the transmission data phase.

The DSL access multiplexer according to claim 15, wherein the channel estimation module is further configured to estimate a line pair in a transmission data stage according to the augmented pilot sequence and the error sample. The crosstalk cancellation factor for the newly added pair.

An xDSL system, comprising: a client device CPE and a central office CO, wherein the client device is configured to use a crosstalk cancellation coefficient between a pair of lines currently in a transmission data phase and a newly added pair Number of notifications to the central office;

The xDSL system according to claim 17, wherein the central office is further configured to estimate, according to the initial pilot sequence, a crosstalk cancellation coefficient between newly added pairs, according to the new joining line. Constructing an augmented pilot sequence based on the initial pilot sequence on the crosstalk cancellation coefficient in the transmission data phase pair and the crosstalk cancellation coefficient between the newly added pairs, according to the augmented pilot sequence Estimating the crosstalk cancellation coefficient between the pair of newly added pairs in the transmission data phase pair and/or the crosstalk cancellation coefficient between the newly added pairs.

The xDSL system according to claim 17, wherein the central office is further configured to re-group the newly added pair and the data phase in the transmission data phase, according to the result of the regrouping, The augmented pilot sequence is constructed based on the initial pilot sequence.

The xDSL system according to claim 19, wherein the central office is further used for

The xDSL system according to claim 19, wherein the central office is further configured to perform re-grouping processing on the re-grouped new joining pair and the transmitting data phase pair.