WO2007033605A1 - Procede permettant d'effectuer une selection automatique de mode de fonctionnement dans un reseau xdsl et appareil a cet effet - Google Patents

Procede permettant d'effectuer une selection automatique de mode de fonctionnement dans un reseau xdsl et appareil a cet effet Download PDF

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Publication number
WO2007033605A1
WO2007033605A1 PCT/CN2006/002492 CN2006002492W WO2007033605A1 WO 2007033605 A1 WO2007033605 A1 WO 2007033605A1 CN 2006002492 W CN2006002492 W CN 2006002492W WO 2007033605 A1 WO2007033605 A1 WO 2007033605A1
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WIPO (PCT)
Prior art keywords
mode
subcarrier
signal
bits
xdsl network
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PCT/CN2006/002492
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English (en)
Chinese (zh)
Inventor
Jun Zhou
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Huawei Technologies Co., Ltd.
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Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Publication of WO2007033605A1 publication Critical patent/WO2007033605A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
    • H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
    • H04M11/062—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors using different frequency bands for speech and other data
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0044—Arrangements for allocating sub-channels of the transmission path allocation of payload

Definitions

  • the present invention relates to the field of network communication technologies, and in particular, to an implementation method and apparatus for automatically selecting an operation mode in an XDSL network. 'Invention background
  • the ITU-T standard cluster specifically includes: ADSL (Asymmetric Digital Subscriber Line)
  • ADSL2 Second Generation Asymmetric Digital Subscriber Line
  • ADSL2+ Second Generation Asymmetric Digital Subscriber Line for Downstream Bandwidth Expansion
  • SHDSL G. 991. 2
  • VDSL Very High Speed Digital Subscriber Line
  • VDSL2 second generation very high speed digital subscriber line
  • each standard also defines appendices to meet different business or regional needs, including ADSL2 annex L (ADSL2 for extended transmission distance), which can also be called READSL2.
  • VDSL2 will also support VDSL2, VDSL1, ADSL2+, ADSL2 and READSL2.
  • annex L of the PSD mask is higher than ADSL2 annex A's PSD mask
  • ADSL2 annex A's PSD mask is higher than ADSL2+ annex A's PSD.
  • ITU-T In an xDSL network, in order to select an optimal operating mode among a plurality of standard operating modes, ITU-T defines a handshake protocol G.hs, which can be used in xTU-C (xDSL central office unit) and xTU. - R (xDSL client unit) negotiates the operating mode and passes configuration parameters to facilitate the selection of the best operating mode in the xDSL network for a better transmission rate.
  • G.hs xDSL central office unit
  • xTU- R xDSL client unit
  • both xTU-C and xTU-R support a multi-mode mode, which is available at both ends.
  • ADSL2+ annex A ADSL2 annex A, ADSL2 annex L, ADSL annex A, G. lite annex A, or both VDSL2, VDSL, ADSL2+ annex A, ADSL2 annex A, ADSL2 annex L ADSL annex A, G. lite Annex A. Therefore, in order to facilitate the selection of the operation mode, it is necessary to conveniently select an optimal operation mode according to certain rules in both the central office and the user terminal.
  • Automode for automatic selection of operating modes is proposed in the ITU-T standard. Since Automode is selected based on: The selected operating mode is to maximize the sum of the upstream and downstream rates. Therefore, by calculating the SNR (Signal to Noise Ratio) is a very easy to think method, the specific implementation is: According to Medley in the handshake process - 4-bit AMQ (Quadrature Amplitude Phase Modulation) A table of signal-to-noise ratio SNR for each subcarrier that can be obtained by modulating the signals obtained from all used subcarriers, ATU-R (ADSL client unit) and ATU-C (ADSL central office unit) exchange this table ATU C uses this table to calculate the possible speeds of the various modes up and down, and then selects the operation mode that meets the above requirements according to the result, and restarts the training. At this time, the operation mode given by the ATU-C is the last training. The pattern obtained.
  • ATU-R ADSL client unit
  • ATU-C ADSL central office unit
  • This mode of operation which requires secondary training, can maximize the proximity to the standard requirements, but because of the need for secondary training and long training time, it takes longer to determine the optimal operating mode. It is very likely that the time limit required by the standard is exceeded, and the implementation process is obviously more complicated.
  • another Automode implementation method that can be used is: judging the length of the line according to the attenuation of the handshake signal sent by the xTU-R during the handshake, specifically estimating the attenuation by the signal amplitude, and then based on the line length, and based on experience Parameters to select the appropriate operating mode. For example, use ADSL2+ annex A within 2. 8km, ADSL2 between 8km and 3. 8km, and ADSL2 annex L for more than 3. 8km.
  • This method is simple and does not require an increase in the time of the handshake process.
  • this method is based on the uplink handshake signal to infer the line length, and the method of selecting according to experience is too rough, mainly because the attenuation of the uplink signal cannot reliably express the attenuation in the downlink direction and infer the capacity, which often leads to the selection of Automode.
  • the rate of the operating mode is rather low.
  • FIG. 1 shows that when the method is used for mode selection switching, the switching point will cause a large rate jump and affect the transmission performance. Summary of the invention
  • the object of the present invention is to provide an implementation method and device for automatically selecting an operation mode in an XDSL network, so that an optimal operation mode can be automatically selected according to the current situation of the XDSL network, and the highest operation mode can be obtained based on the selected operation mode. Transmission rate.
  • the object of the invention is achieved by the following technical solutions:
  • the present invention provides an implementation method for automatically selecting an operation mode in an XDSL network, including: the central office unit sends a group of subcarrier signals in multiple modes to the client unit;
  • the operating mode is selected in the DSL network according to the number of bits that can be carried in each mode.
  • the processing of transmitting a set of subcarrier signals in the multi mode includes:
  • the central office unit transmits the subcarrier signals included in all frequency bands to the client unit, or transmits all subcarrier signals included in the frequency band above the last frequency in the low frequency band mode, or transmits the comb subcarrier signal.
  • the processing of transmitting a group of subcarrier signals in the multi mode further includes:
  • the central office unit needs to reduce the transmission power value according to the signal amplitude sent by the received client unit, or directly reduce the transmission power. After a fixed power value, the subcarrier signal of the reduced power value is sent to the client unit.
  • the subcarrier signals are transmitted at periodic intervals.
  • the processing for determining the number of bits that can be carried in each mode specifically includes:
  • the processing for calculating the signal power value of each subcarrier and the background noise power value corresponding to each subcarrier includes: the client unit receives the subcarrier transmitted by the central office unit, and calculates a signal power value, and the authority unit stops transmitting the subcarrier. Then, the background noise power value corresponding to the subcarrier is calculated.
  • the number of bits b that each subcarrier can carry is:
  • Ratio, S ⁇ g ⁇ is SN R gap, and the TARSN leg is a predetermined target noise margin.
  • the processing for determining the selected mode specifically includes:
  • steps Cl, C2 can be repeated until one mode is finally selected.
  • the processing for determining the number of bits that can be carried in each mode specifically includes: Calculating, on the client unit, a signal to noise ratio of each subcarrier according to the received subcarrier signal, and determining a number of bits that can be carried in each mode according to the signal to noise ratio;
  • the information obtained by the measurement is sent by the client unit to the central office unit, and the central office unit calculates the signal to noise ratio of each subcarrier according to the information, and determines the number of bits that can be carried in each mode according to the signal to noise ratio.
  • the method further includes: performing processing of determining the selected mode when the DSL transceiver training is completed, and changing the current operating mode after determining the operating mode.
  • the process of changing the current operating mode includes - if the SNR is calculated using the signal C-Reverb signal superimposed by all carriers, then the 4-QAM signal C-medley is modulated to start changing the operating mode and the corresponding spectrum;
  • the power spectrum is adjusted to the corresponding mode by the bit and gain table, and the corresponding operation mode information is transmitted in the message R-MSG2 of the user equipment.
  • the present invention also provides an apparatus for automatically selecting an operation mode in an XDSL network, including:
  • the bearer capability calculation module calculates the number of bits that can be carried in each mode according to the information measured by the client unit;
  • the mode selection module selects an operation mode between the central office unit and the client end unit according to the number of bits that can be carried in each mode determined by the bearer capability calculation module.
  • the present invention also provides a system for automatically selecting an operating mode in an XDSL network, including a client unit and a central office unit, including the apparatus for automatically selecting an operating mode in the XDSL network, and further comprising:
  • a subcarrier sending module disposed in the central office unit, configured to perform subcarrier transmission processing according to a predetermined condition
  • a measurement module disposed in the client unit is configured to measure signal power of the subcarrier and corresponding background noise power, and provide the load capacity calculation module to the load capacity calculation module.
  • the device for automatically selecting the operating mode is set on the client unit or the central office unit, or is set independently of the user unit and the central office unit.
  • the present invention can be implemented according to the actual conditions of the line. Automode's operating mode is selected, and the best operating mode can be selected as long as it is trained. At the same time, the invention can also be extended to the case where the VDSL2 is compatible with ADSL2+ annex A, ADSL2 annex A, ADSL2 annex L, and the automatic selection of ADSL2+ annex B and ADSL2 annex B can also be realized.
  • the operation mode selection implementation provided by the present invention not only does not need to increase the handshake time and complexity, but also can effectively improve the accuracy of the mode in which the selected mode is the rate maximization mode.
  • FIG. 1 is a schematic diagram of a line attenuation process in the prior art
  • Figure 2 is a schematic diagram of the use of the downlink frequency band in various operating modes
  • FIG. 3 is a schematic diagram of a specific implementation process of the method according to the present invention.
  • FIG. 4 is a schematic diagram of a line attenuation process in the present invention.
  • FIG. 5 is a schematic diagram of a specific implementation structure of the system according to the present invention. Mode for carrying out the invention
  • the abscissa is the frequency value
  • the ordinate is the power spectral density value (DB)
  • the in-band spectrum in each of the selectable modes is -
  • the upstream frequency band of the ADSL2+4 dish 6 4 mode is 25.875 ⁇ 1381 (the tone number is 6 ⁇ 31, the downlink frequency band is: 138KHz ⁇ 2208KHz, and the tone is from 32 to 511;
  • the uplink frequency band of ADSL2 Annex A mode is the same as ADSL2+ Annex A, and the downlink frequency band is: 138KHz to 1104KHZ, and the tone is from 32 to 255;
  • the uplink band (wideband) of the ADSL Annex L mode is 25.875 ⁇ 103. 5KHz, the tone number is 6 ⁇ 23, the downlink frequency band is: 138KHZ to 552KHz, and the tone is from 32 to 127.
  • the core of the present invention is to select the operating mode by comparing the in-band bit increment and the out-of-band bit increment according to the difference of the bit bearer caused by the in-band spectrum difference of various modes (such as the above three modes), thereby selecting one type.
  • the operating mode with the highest transfer rate can be obtained.
  • the selection made in the present invention can be performed in the CPE (the CPE directly selects the operation mode according to the calculation result), or the information can be transmitted to the central office by the CPE, and the mode selection operation is performed by the central office.
  • the difference between the number of bits of the in-band portion in the narrowband mode is calculated as the difference between the number of bits of the same subcarrier set in the adjacent broadband mode and the narrowband band as the in-band increment, and the narrowband mode is calculated out-of-band but The number of bits in the broadband mode band in the broadband mode band as the out-of-band increment; when the in-band increment is greater than the out-of-band increment At the same time, the narrowband mode is selected. Otherwise, the judgment is continued until the mode selection is completed, that is, the current narrowband mode is used as the broadband mode, and the mode adjacent to the narrower band mode is used as the narrowband mode, and the above operation is performed again. .
  • the comb subcarrier signal may be a subset of the C-Comb signal of ADSL2+, and if a comb subcarrier is used, the bit bearing of the tone between the two combs is calculated using interpolation.
  • all the subcarrier signals or the comb subcarrier signals transmitted in the present invention are transmitted by using the method of transmitting the interval, the transmission signal period is used for the CPE to measure the subcarrier signal power, and the silent phase CPE is used to measure the background noise power. To calculate the signal to noise ratio value.
  • the method of the present invention can also be used for VDSL2 support READSL2, ADSL2 annex A, ADSL2+ annex A, that is, there are four modes of operation. Select, so from VDSL2 DS1 to ADSL2+ to ADSL2 annex A, and finally between READSL2, to achieve automatic selection of operating mode.
  • the method described in the present invention may include the following steps in a specific implementation process:
  • Step 31 The ATU-C sends the modified C-Tones signal
  • ATU-C sends tones 40, 56, 64.
  • the present invention modifies the C-Tones signal, and specifically can send three C-Tones signals:
  • the second is to send tones from 128 to 511;
  • the third is to send the C-Comb signal of the channel discovery phase of ADLS2+ annex A, namely tone 35, 47, 59, 64, 71, 83, 95, 107, 119, 143, 179, 203, 227 and 251 and All 251+kx24 (k is an integer, and 251+kx24 ⁇ 511), for VDSL2, send with channel discovery Same signal
  • the CO office
  • power reduction is not required because the power itself is only 8.9 dBa.
  • the modified C-Tones signal sent by the CO is also switched at a certain period, such as transmitting a 16ms signal, then muting for 16ms, and then looping back and forth.
  • Step 32 When there is a signal, the CPE estimates the signal power Ps of each tone. When there is no signal, the CPE estimates the background noise power ⁇ on each tone.
  • Bit ⁇ i) log 2 (l + l 0 ( ) " - erli) / ⁇ ) b it ⁇ is the number of bits carried by T 0ne ⁇ , S Qing is the signal-to-noise ratio of T ° ne ⁇ >, Snr S a P is an SNR gap. According to T1. 417, for DMT modulation, the size may be 9.75 dB, and TARSNRM is a preset target noise margin.
  • Step 33 Determine whether the automatic mode is supported in the ATU-C, that is, whether the implementation of the automatic mode selection provided by the present invention is supported, and if yes, step 35 is performed; otherwise, step 34 is performed;
  • Step 34 Ignore each information, and perform a normal handshake process to select a running mode by using a handshake process.
  • the operation mode provided by the prior art may be used to select an operation mode, or other modes may be used.
  • Step 35 Determine whether the number of bits of T 0n el28- 511 is less than 96, if yes, proceed to step 36, otherwise, perform step 37;
  • Step 36 Select READSL2 mode;
  • Step 37 Determine whether the number of bits of T 0ne 256- 511 is less than 75, if yes, proceed to step 38, otherwise, perform step 39;
  • Step 38 Select ADSL2 annex A mode
  • Step 39 Select ADSL2+ annex A mode.
  • Steps 35 to 39 in the above process are the core technical content of the implementation of the present invention. To facilitate the understanding of the present invention, the feasibility of the processing described in the steps 35 to 39 will be analyzed and explained below.
  • the transmission power of ADSL2/ADSL2+ and READSL2 shall not exceed 19.8dBm according to the requirements of ITU-T G.992.X and spectrum management.
  • the flat cut back scheme is also specified in the standard. Therefore, it can be calculated that the in-band (tone 32 ⁇ 127) power spectral density of READSL2 is 3 dB higher than the frequency band (tone32 ⁇ 127) corresponding to ADSL2, and the in-band (tone 32 ⁇ 255) power spectral density of ADSL2 is higher than that of ADSL2+.
  • the corresponding frequency band (tone 32 ⁇ 255) is high ldB, as shown in Figure 2.
  • the process given above is only one specific implementation. Considering that the transceiver has not been trained in the C Tones phase (such as the automatic gain control AGC needs to be trained to determine), it may affect the signal-to-noise ratio calculation. Accuracy. Therefore, it is also possible to start the period in which the transceiver training is completed. For example, all signals covering the entire frequency band such as the C-reverb signal and the C-medley signal after C Reverbl can be used to calculate the signal-to-noise ratio.
  • the present invention in view of the fact that the mode selection phase may have been missed, the present invention also introduces a mechanism for changing the operation mode during the training process, which may specifically be:
  • C-Reverb signal superimposed with all carriers modulated with (0, 0)
  • C-medley modulated 4-QAM (generated by a pseudo-random sequence generator) all carrier superimposed signals
  • the power spectrum is adjusted to the corresponding mode by the bit&gain table (bit and gain table), and the corresponding operating mode information is transmitted in R-MSG2 (message 2 of the client device). .
  • the signal can be roughly based on the R-Tone-REQ (activation request signal) Judging to choose, and then performing an accurate calculation according to the above scheme.
  • the present invention also provides a system for automatically selecting an operation mode in an xDSL network.
  • the specific implementation structure includes: an apparatus for automatically selecting an operation mode in an XDSL network, where the device is installed in a client unit or On the central office unit, or independent of the user end unit and the central office unit device, FIG. 5 is only taken as an example of setting it on the client end unit, and when the device is set on the central office unit, the user end is required.
  • the unit sends corresponding measurement information to the device in the central office unit, so that the device performs mode selection processing according to the information;
  • the system further includes a subcarrier sending module disposed in the central office unit, configured to perform subcarrier transmission processing according to a predetermined condition (that is, three subcarrier signal transmission manners described in the foregoing step 31), and simultaneously
  • the measurement module is disposed in the client unit, and is configured to measure the signal power of the subcarrier and the corresponding background noise power, and provide the bearer capability calculation module in the device that automatically selects the operation mode in the XDSL network.
  • the specific implementation structure of the apparatus for automatically selecting an operation mode in the XDSL network in the system of the present invention is still as shown in FIG. 5, and specifically includes a bearer capability calculation module and a mode selection module, respectively:
  • a bearer capability calculation module configured to calculate, according to the information measured by the client unit, the bit rate information that can be carried in each mode
  • the mode selection module selects an operation mode between the central office unit and the client end unit according to the number of bits that can be carried in each mode determined by the bearer capability calculation module.
  • the simulation results show that the mode selection implementation provided by the present invention can obtain better results, as shown in FIG. 4, and it can be seen in FIG. 4 that with the switching method of the present invention, the rate jump of the switching point is small. .
  • the present invention can automatically select the operating mode according to the actual conditions of the line, and can select the best operating mode as long as one training is performed.
  • the invention can also be extended to the case of VDSL2 compatible ADSL2+ annex A, ADSL2 annex A, ADSL2 annex L, and can also realize automatic selection for ADSL2+ annex B and ADSL2 annex B mode.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Telephonic Communication Services (AREA)

Abstract

La présente invention concerne un procédé permettant d'effectuer une sélection automatique de mode de fonctionnement dans un réseau XDSL et le système à cet effet. Ce procédé consiste principalement: d'abord un terminal local envoie un groupe de signaux d'onde de sous porteuse en multimode à un terminal utilisateur, puis calcule le nombre de bits que chaque onde de sous porteuse peut porter en fonction des signaux d'onde de sous porteuse reçus par le terminal utilisateur et, détermine le nombre de bits que chaque mode peut porter en fonction de ce nombre de bits, enfin détermine le mode sélectionné en fonction du nombre de bits que chaque mode peut porter. Cette invention peut effectuer la sélection automatique de modes de fonctionnement en fonction de la situation réelle des lignes et sélectionner le meilleur mode de fonctionnement avec lequel un entraînement a été réalisé. Par conséquent la réalisation de cette invention permet de supprimer la nécessité d'ajouter un temps de salutation et un degré de complexité et peut efficacement accroître la précision du mode sélectionné et utilisé.
PCT/CN2006/002492 2005-09-26 2006-09-22 Procede permettant d'effectuer une selection automatique de mode de fonctionnement dans un reseau xdsl et appareil a cet effet WO2007033605A1 (fr)

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CNB2005101066948A CN100563290C (zh) 2005-09-26 2005-09-26 Xdsl网络中自动选择运行模式的实现方法及装置
CN200510106694.8 2005-09-26

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CN101686067B (zh) * 2008-09-27 2013-08-28 华为技术有限公司 一种信号调整方法、装置及系统
CN106464460B (zh) * 2014-11-06 2019-09-03 华为技术有限公司 非线性预编码的比特加载方法、发送端、接收端及系统
CN110493478B (zh) * 2019-08-02 2021-02-09 深圳市普威技术有限公司 一种自适应传输模式的xDSL设备及系统

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US6084881A (en) * 1997-05-22 2000-07-04 Efficient Networks, Inc. Multiple mode xDSL interface
US6804267B1 (en) * 1997-10-25 2004-10-12 Centillium Communications, Inc. Transceiver training for DSL modems under TCM-ISDN interference
CN1602039A (zh) * 2004-10-27 2005-03-30 西安大唐电信有限公司 甚高比特率数据用户线速率自适应配置的方法

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US6084881A (en) * 1997-05-22 2000-07-04 Efficient Networks, Inc. Multiple mode xDSL interface
US6804267B1 (en) * 1997-10-25 2004-10-12 Centillium Communications, Inc. Transceiver training for DSL modems under TCM-ISDN interference
CN1602039A (zh) * 2004-10-27 2005-03-30 西安大唐电信有限公司 甚高比特率数据用户线速率自适应配置的方法

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