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Vectoring Technology White Pager

Issue 1.0

Date 2012-03-12

HUAWEI TECHNOLOGIES CO., LTD.

V1.0 (2012-03-12) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd.

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Copyright © Huawei Technologies Co., Ltd. 2012. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd. Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd. All other trademarks and trade names mentioned in this document are the property of their respective holders. Notice The purchased products, services and features are stipulated by the contract made between Huawei and the customer. All or part of the products, services and features described in this document may not be within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information, and recommendations in this document are provided "AS IS" without warranties, guarantees or representations of any kind, either express or implied. The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations in this document do not constitute a warranty of any kind, express or implied.

Huawei Technologies Co., Ltd.

Address: Huawei Industrial Base Bantian, Longgang Shenzhen 518129 People's Republic of China

Website: http://www.huawei.com

Email: [email protected]

Vectoring Technology White Paper About This Document


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About This Document

Overview Ever since its birth in the 1990s, the rapid development of copper access technologies has enabled digital subscriber line (DSL) to be a ubiquitous solution and become today's most widely used and most successful fixed broadband access technology. To date, approximately 300 million DSL lines have been deployed worldwide. Meanwhile, DSL technologies have been breaking new grounds and maturing. Services supported have diversified from the initial pure data transmission to nowadays' Multi-Play services, including high-speed Internet access, IPTV, VoIP, private line access, mobile backhaul, and remote power supply.

As the bandwidth requirements of the "last mile" access are booming, the "reach vs. rate" contradiction of DSL is increasingly intensified. New services such as IPTV and mobile backhaul are also putting higher demands on stability and reliability of DSL. Crosstalk between twisted pairs has become the main factor that affects the rate, stability, and reliability of the DSL line. To cope with crosstalk, the Vectoring technology comes into being. This technology uses various methods such as crosstalk detection, compensation, and cancellation to achieve the best DSL performance in the "crosstalk-free" environment. Moreover, this technology fully explores potentials for copper access and meets carriers' requirements for smooth evolution, low costs, fast time-to-market, and is manageable and controllable O&M.

This document describes the Vectoring technology, including its origin, technology principle and standard, product implementation, application and deployment scenarios, and evolution trend. This document also describes Huawei's contribution in the Vectoring field and end-to-end Vectoring products and solutions.

Change History Date Revision Version Description Author

2012-03-12 1.0 Initial official release. Li Xiaodong (ID: 162659) Huang Lei (ID: 129620)

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Vectoring Technology White Paper Contents


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Contents

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1 Origin .............................................................................................................................................. 1 1.1 Origin ............................................................................................................................................................... 1 1.2 Technology Principle and Standard .................................................................................................................. 2 1.3 Prospects .......................................................................................................................................................... 4

2 Vectoring Productization ............................................................................................................. 6 2.1 Challenges ........................................................................................................................................................ 6 2.2 Consideration ................................................................................................................................................... 7 2.3 Practice ............................................................................................................................................................. 8

3 Application and Deployment ..................................................................................................... 9 3.1 Vectoring Adaptation to Various Application Scenarios ................................................................................... 9 3.2 Good QoE Guarantee ..................................................................................................................................... 10 3.3 Comprehensive Support for Vectoring Solution ............................................................................................. 11

4 Huawei E2E Vectoring Solution............................................................................................... 13 4.1 Huawei's Vectoring Contribution and Innovation .......................................................................................... 13 4.2 Huawei E2E Vectoring Solution ..................................................................................................................... 13

5 Faster and More Powerful Copper Access ............................................................................. 16

6 Summary ....................................................................................................................................... 18

A Acronyms and Abbreviations .................................................................................................. 19

B References .................................................................................................................................... 22

Vectoring Technology White Paper 1 Origin


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1 Origin

1.1 Origin Currently, requirements for smooth evolution, low costs, fast time-to-market, and easy O&M have become the main targets for broadband access network construction. Based on these requirements, "Fiber-in copper-out" is blossoming in the access network. Fiber moves closer to users and copper plants are shorten, and FTTx network is widely introduced and developed, including FTTN, FTTC, FTTB, and FTTH. In the access network, VDSL2 is the main access mode to face the "last mile" challenge because of its high bandwidth (ideally, 100 Mbit/s) over a short distance. However, VDSL2 requires high frequency which introduces crosstalk between copper lines. Compared with single-pair crosstalk-free VDSL2 access, the bandwidth on multi-pair bundle’s VDSL2 access decreases sharply as more pairs are used, because of the increasing impact of crosstalk. The larger the number of copper lines in a bundle of cable, the higher crosstalk is generated. Therefore, crosstalk is the main factor that impairs the VDSL2 performance.

DSL crosstalk is divided into near-end crosstalk (NEXT) and far-end crosstalk (FEXT), as shown in Figure 1-1. In NEXT, Tx signals are sent from the disturber pair, coupled to the victim pair, and then are sent to the near-end Rx end of the victim pair. In FEXT, Tx signals are sent from the disturber pair, coupled to the victim pair, and then are sent along the victim pair, to the far-end Rx end of the victim pair. For DSL, NEXT is interference between upstream signals and downstream signals of different pairs; FEXT is interference between upstream signals of different pairs or between downstream signals of different pairs.

Figure 1-1 NEXT and FEXT


Issue 1.0 (2012-03-12) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd.

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The VDSL2 system uses frequency division multiplexing (FDM), Tx signals of the disturber pair and Rx signals of the victim pair use different frequencies. Therefore, the impact of NEXT on the VDSL2 access can be eliminated or significantly decreased by using a filter. However, FEXT signals of the disturber pair cannot be eliminated through the filter because they have the same frequency as the normal Rx signals of the victim pair. In addition, VDSL2 requires short transmission distance (usually within one kilometer) and high frequency (30 MHz at highest). As a result, FEXT in VDSL2 is more serious than other traditional DSL technologies and becomes the main factor that affects its performance. FEXT leads to signal-to-noise ratio (SNR) decrease, which reduces the line data rate or increases the bit error rate (BER), or potentially resynchronization, severely affecting system stability and customer experience.

To cope with FEXT, the dynamic spectrum management (DSM) technology has been widely used to adjust Tx signals of DSL lines in the same bundle to balance the DSL performance and stability. There are four levels from level 0 to level 3 in the development of the spectrum management technology as shown in Figure 1-2. Level 0–level 2 partially decrease FEXT and optimize DSL performance and stability by managing spectrum of Tx signals of single-pair DSL lines or multi-pair DSL lines. However, FEXT cannot be canceled completely.

Figure 1-2 Development of the spectrum management technology

To fully cancel FEXT from VDSL2, ITU-T formulates the Vectoring technology standard, a.k.a. DSM level 3. Vectoring technology cancels most of VDSL2’s mutual FEXT, thus improving VDSL2 performance obviously.

1.2 Technology Principle and Standard The principle of vectoring technology is depicted in Figure 1-3. According to communications principles, Rx signal Yn is the product of Tx signal Xn and Channel transmission function Hnn. For simplicity, this document uses the upstream direction (from the CPE to CO) of two DSL lines as an example for analysis. As shown in the following figure, in ideal transmission



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without crosstalk, Yn = Hnn*Xn. With FEXT, distortion h12*x2 is added to y1 and distortion h21*x1 is added to y2.

In the upstream direction (the CO end), the Vectoring system uses the FEXT decoder to extract the FEXT information, and then removes the FEXT information from the original Rx signals to get the nearly crosstalk-free performance. In the downstream direction, the CPE feeds back the FEXT information to the CO in the way negotiated between the CPE and the CO, and then the CO uses the FEXT pre-coder to pre-code the FEXT information to the normal Tx signals. After that, the pre-coded signals and the FEXT information are canceled in transmission and the Rx end receives the correct information almost without crosstalk.

Figure 1-3 Vectoring technology principles

To accelerate the application of Vectoring, ITU-T formulated the G.993.5 standard in 2010 and amended the existing standards including G.993.2, G.994.1, and G.997.1. The Broadband Forum (BBF, formally known as DSL Forum) focuses on Vectoring's performance, test, interoperability, and O&M. Moreover, China and North America may also formulate proprietary Vectoring standards or specifications.

Table 1-1 describes the International standards and specifications about Vectoring.

Table 1-1 International standards and specifications about Vectoring

Standard Organization

Standard ID

Standard Description First Release

Vectoring Amendment

ITU-T

G.993.5 (G.vector)

Self-FEXT cancellation (Vectoring) for use with VDSL2 transceivers

2010 Amd 1

G.993.2 (G.vdsl)

Second-generation VDSL transceivers 2006 Amd 5, Amd 6



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G.994.1 (G.hs)

Handshake procedures for DSL transceivers 1999 Amd 5, Amd 8

G.997.1 (G.ploam)

Physical layer management for DSL transceivers

1999 Amd 1, Amd 3, Amd 4

BBF

WT-249

Testing of G.993.5 self-FEXT cancellation (Vectoring) for use with VDSL2 Transceivers

2011 -

TR-252 issue 2

xDSL protocol-independent management model

- -

1.3 Prospects Theoretically, Vectoring can fully cancel FEXT impacts on the VDSL2 performance, and achieve higher data rate over the same distance, or larger coverage with the same data rate. The curves shown in figure 1-4 represent the "reach vs. rate" performance of VDSL2 (17a profile, B8-11 PSD mask, line diameter 0.4 mm) in the downstream direction as an example. From the figure, it can be seen that the VDSL2 performance in the crosstalk-free environment is 50–90% higher than which in the FEXT environment without Vectoring. The result shown in Figure 1-4 also indicates that the denser the lines and the higher the number provisioning rate, the stronger the FEXT. Therefore, vectoring technology plays an important role in the improvement of VDSL2 performance. The VDSL2 performance in the upstream direction is similar to that in the downstream direction.

Figure 1-4 Performance comparison for VDSL2 with and without Vectoring

Vectoring, as a new generation technology for improving the performance, is compatible with the other DSL technologies, including retransmission (G.inp), bonding, network time



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reference (NTR), seamless rate adaption (SRA), and bit swap (BS), etc. With all these technologies, Vectoring can be flexibly used in various scenarios, such as residential user access, commercial user access, mobile backhaul, and remote access site backhaul.

Figure 1-5 Vectoring application scenarios

Vectoring Technology White Paper 2 Vectoring Productization


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2 Vectoring Productization

2.1 Challenges The Vectoring system jointly processes signals of all VDSL2 pairs in a Vectoring group (jointly sending signals in the downstream direction and jointly receiving signals in the upstream direction) to cancel self-FEXT and improve performance.

Compared with the VDSL2 system reference model, the Vectoring system adds the vectoring control entity (VCE) and the interface between the VTU-Os and the ME (Management Entity), as shown in red in Figure 2-1. Inside the AN, the ME further conveys the management information for a particular line (over an interface here called ε-m) to the vectoring control entities (VCEs) of the Vectoring group that line belongs to. Each VCE controls a single vectored group, and controls VTU-O-n (connected to line n in the vectored group) over an interface here called ε-c-n. Pre-coder data are exchanged between VTU-O-n1 and VTU-O-n2 over an interface here called ε-n1-n2. Figure 2-1 shows the first pair in the Vectoring group.

Figure 2-1 Reference model of the Vectoring system [ITU-T G.993.5]



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The main challenge for Vectoring productization is how to transmit and process the mass data with high reliability and easy O&M. Specifically, the main challenge is the ε-n1-n2 interface. A pair in the N-pairs Vectoring group exchanges the pre-coded data with another N - 1 pair. When the Vectoring system capacity increases, huge amounts data need to be exchanged. Here, the 48-port Vectoring line card is used as an example. The bandwidth for transmitting the pre-coded data will be 20-30 Gbit/s. If an AN contains multiple Vectoring line cards, the bandwidth will be hundreds of Gbit/s, which is close to or beyond the data transmission volume of an optical access equipment.

2.2 Consideration Similar to the Vectoring system reference model, the Vectoring product need integrate Vectoring process (VP) parts and related interfaces based on the current DSL AM product. Different carriers' networks in different countries/areas have different AN site models. Accordingly, Huawei provides different specifications and has different implementation considerations for Vectoring productization. As shown in Figure 2-2, the small-capacity Vectoring products normally do not use independent VP card. Instead, the VP parts are integrated in the same card with parts such as the main control unit and DSL access unit. The medium and large-capacity Vectoring products use independent VP card, featuring high-efficient and more-flexible processing architecture.

Figure 2-2 Vectoring product architecture

For medium and large-capacity Vectoring products, DSL line cards and VP card communicate with each other in a super-high speed backplane buses or external cables. Compared with the external cable, the backplane bus will be highly reliable for hardware connection and service assurance, facilitates cards’ interconnection, and saves space in installation, ensuring high reliability and easy O&M of the Vectoring system.

Furthermore, the Vectoring technology speeds up the downward DSL user network interface (UNI). Accordingly, the "speedup" challenge arises in the bandwidth of the convergence interface on the backplane of the DSL line card, traffic processing capability of the control card, and convergence bandwidth of the upward network node interface (NNI). This issue also needs to be considered in Vectoring productization.



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2.3 Practice In the 3rd quarter of 2010, Huawei took the lead in launching a small-capacity Vectoring prototype. In the 3rd quarter of 2011, Huawei released a cross-equipment large-capacity Vectoring prototype, the first of its kind in the industry. To date, Huawei has partnered with many worldwide tier-1 carriers for Vectoring testing. The typical test results are shown in Figure 2-3, which are taken with some Tier-1 carrier in Europe.

Figure 2-3 Results for lab test and live network validation

The relevant results are:

CO-based ADSL2+ has little impact on RT-based Vectoring, which can be omitted. ADSL2+ coexisting on CO or RT has little impact on Vectoring, which is acceptable. VDSL2 coexisting on CO or RT has serious impacts on Vectoring. One VDSL2 alien line

significantly affects Vectoring, and more VDSL2 alien lines may lead to lower Vectoring performance and BER increase, or potentially resynchronization.

Vectoring solves only the FEXT impacts on VDSL2 performance but cannot solve other line issues, such as bridge tap, mixed connection, or improper connection.

Vectoring Technology White Paper 3 Application and Deployment


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3 Application and Deployment

According to the current technology and product maturity, Huawei points out that Vectoring application and deployment face the following TOP challenges:

Vectoring adaptation to various application scenarios Good quality of experience (QoE) guarantee Comprehensive support for Vectoring solutions

3.1 Vectoring Adaptation to Various Application Scenarios Having developed for more than 10 years, traditional DSL technologies including SHDSL, SHDSL.bis, ADSL, ADSL2+, VDSL1, and VDSL2 coexist on live networks. As a new DSL technology, Vectoring has the challenge to coexist with these traditional DSL technologies. In addition, requirements for bandwidth, supervision institutions, carriers, and equipment manufacturers may affect Vectoring application and deployment. Except for "E2E 100% Vectoring capable" scenario, Vectoring faces the following adaption scenarios’ challenges:

Scenario 1. "Fiber-in copper-out" for a single carrier: In the long-term "Fiber-in copper-out" evolution, RT based Vectoring will coexist with CO or RT based SHDSL, SHDSL.bis, ADSL, and ADSL2+ (excluding RT based VDSL2) in the same bundle.

Scenario 2. "Loop unbundling" for multiple carriers: Including CO based local loop unbundling (LLU) and RT based sub loop unbundling (SLU). Some countries and areas, such as Europe and Australia, require LLU or even SLU. SLU has more serious requirements than LLU and therefore Vectoring may be affected by severe VDSL2 interference from the same site or the same bundle, or even interference among Vectoring equipments provided by different carriers or equipment manufactures.

Scenario 3. "Reluctant coexistence" caused by interoperability between the Vectoring CO and legacy DSL terminals: In practical Vectoring deployment, some legacy DSL terminals may not support Vectoring. These alien lines will become disturbers interfering with the other Vectoring lines. If the legacy terminal synchronizes in VDSL2 mode, this scenario is similar to scenario 2.

Huawei provides a variety of processing options to meet different scenarios at various Vectoring deployment stages, under various regulating conditions, and for carriers across countries and regions:

In scenarios where Vectoring coexists with traditional DSL technologies such as SHDSL, SHDSL.bis, ADSL, and ADSL2+, Vectoring provides techniques such as downstream



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power back-off (DPBO) and PSD shaping to eliminate the impact of those low-frequency interference sources such as SHDSL, SHDSL.bis, ADSL, and ADSL2+.

In scenarios where Vectoring and VDSL2 coexist over the same carrier network, Huawei provides three coexistence policies (no coexistence, limited coexistence, and full coexistence), which can be flexibly selected or adjusted by carriers at different Vectoring deployment stages.

In scenarios where Vectoring and VDSL2 coexist across different carrier networks because of LLU/SLU regulation, an independent DSM system could be adopted for managing the Vectoring system and VDSL2 system in a unified and harmonious manner while at the same time ensuring service quality. This DSM system balances between general performance optimization and stable coexistence.

In scenarios where Vectoring on different carrier networks coexists because of LLU/SLU regulation, Huawei provides a cross-equipment Vectoring solution. This solution enables coordination between Vectoring equipments of different carriers, which are all provided by Huawei, achieving general performance optimization and stable coexistence. However, the cross-equipment Vectoring solution between different equipment vendors still faces interoperability challenges including architecture, protocol, software, and hardware design and implementation. In the foreseeable short- and mid-term, this solution cannot be realistic and practical.

For the last two scenarios mentioned above, Huawei recommends the virtual loop unbundling (VLU) solution. In a typical VLU solution, only one carrier is 100% responsible for bundle resource management, Vectoring rollouts, and Vectoring O&M to maximally achieve performance improvement brought by Vectoring technology, while other carriers wholesale appropriate channelized bandwidth on demand. The VLU solution achieves not only optimal Vectoring performance but also fairness among carriers, and reduced network rollout and O&M costs, fully guaranteeing end customers' benefits.

3.2 Good QoE Guarantee DSL QoE is mainly affected by the available bandwidth, stability, and synchronization time, so does it for Vectoring QoE.

Many factors affect the available bandwidth of VDSL2, including self-FEXT, impulse noise, radio frequency interference (RFI), and copper line faults. Vectoring addresses the FEXT issue that is the most critical factor affecting VDSL2. As a result, factors hidden behind FEXT will be exposed after Vectoring deployment. Hence, Vectoring needs to be combining deployed with other DSL techniques such as retransmission (G.INP), seamless rate adaption (SRA), bit swap (BS), and RFI notch, for better improving and ensuring the available bandwidth of VDSL2.

When Vectoring is deployed, all lines in the same bundle (or in the same Vectoring group) must coordinate with each other to process signals. If the status of a line changes unexpectedly (for example, an unexpected disorder shutdown event occurs due to factors such as CPE power outage, CPE failure, cable disconnection, board failure at the CO, or manual mis-operation), the other lines in the same bundle (or in the same Vectoring group) may have deteriorating performance (for example, increased BER or even resynchronization). This severely affects the overall system stability.

Traditional DSL lines are activated separately, but Vectoring requires strict synchronization and coordination for activating lines in the same bundle (or in the same Vectoring group). Therefore, the synchronization of Vectoring lines is more time-consuming than that of traditional DSL lines, which is more obvious in scenarios such as concurrent synchronization



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of multiple lines, repeated synchronization of very few rouge lines, and synchronization in a bundle (or a Vectoring group) that contains too many lines.

Huawei's Vectoring system provides built-in intelligent analysis and processing algorithms, and fully leverages various DSL features to significantly expand the available bandwidth while controlling its reliability and synchronization time in a level comparative to traditional DSL technologies.

3.3 Comprehensive Support for Vectoring Solution Facing the complex application scenarios and QoE requirements, a comprehensive, mass deployable, manageable, and controllable Vectoring solution also requires support from the EMS, OSS, terminal management system (TMS)/auto-configuration server (ACS), DSL expert system, and professional engineering/service, because support for Vectoring from CO equipment and CPEs is not enough.

Figure 3-1 Typical Vectoring solution and required equipment/systems

Figure 3-1 shows a typical Vectoring application scenario and required supporting equipment/systems.

1. Vectoring DSLAM: Series Vectoring DSLAMs of different capacities are provided for different site scales and deployment scenarios. A Vectoring DSLAM needs to support traditional DSL technologies (such as VDSL2+, ADSL2+, and ADSL), plug-and-play of different types of CPEs, and smooth evolution of Vectoring.

2. Vectoring CPE: Includes CPEs that fully support Vectoring and Vectoring-friendly CPEs. Normally, VDSL2 CPEs deployed on live networks can become Vectoring CPEs with software upgrades only. (Vectoring-friendly CPEs do not affect the performance of Vectoring lines, but the performance of lines connected to Vectoring-friendly CPEs cannot be improved.)



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3. EMS: Provides graphical Vectoring O&M, which is convenient and simplified. 4. OSS: Supports Vectoring service provisioning and O&M processes, and plans and

controls the schedule of Vectoring service provisioning. 5. TMS/ACS: Manages, upgrades, and maintains CPEs in a centralized manner. An ideal

environment for Vectoring deployment is where all CPEs on the entire network (or at least on the entire site) support Vectoring. Therefore, it is necessary to use the TMS/ACS to upgrade VDSL2 CPEs on live networks before Vectoring deployment.

6. DSL expert system: Monitors DSL quality, evaluates and optimizes DSL performance, and diagnoses copper line faults at a network or site level. To support Vectoring deployment and O&M, the DSL expert system needs to provide functions specially for Vectoring, such as pre-evaluating Vectoring performance, coordinating coexistence of Vectoring and other DSL lines, processing combined application of Vectoring and other DSL features, and preventing and processing Vectoring abnormalities. Providing these functions, the DSL expert system helps achieve Vectoring capabilities that the Vectoring equipment or EMS cannot provide independently.

7. Engineering/Service: Provides services such as network planning, equipment migration, equipment upgrade, data planning, and data migration based on Vectoring evolution/deployment scenarios and equipment models/versions on live networks.

Vectoring Technology White Paper 4 Huawei E2E Vectoring Solution


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4 Huawei E2E Vectoring Solution

4.1 Huawei's Vectoring Contribution and Innovation As an industry-leading vendor in the access network, Huawei has continuously been making contributions to the DSL industry. Huawei holds a large number of VIP positions, such as chairmen and editors, in international standards-defining organizations like BBF, ATIS, and ETSI. Huawei has grown into an influential company that contributes to standards formulation and technical development trends. Furthermore, Huawei actively participates in DSL standardization and works with other companies to promote DSL technologies.

In the Vectoring standards field, Huawei, as one of the two most active equipment vendors, is the editor and main contributor of ATIS COAST-NAI crosstalk channel model. Huawei has proposed several key technique innovations in Vectoring, including the following:

SNR-based estimation of crosstalk channels for legacy lines Channel estimation using error feedback sampled downstream Initialization acceleration by error scaling

In product and solution fields, Huawei has already equipped itself with independent R&D capabilities, enabling Huawei to provide customers with E2E Vectoring products and solutions that are more advantageous in terms of technology and cost. In the 3rd quarter of 2010, Huawei took the lead in launching a small-capacity Vectoring prototype. In the 3rd quarter of 2011, Huawei released a cross-equipment large-capacity Vectoring prototype, which was the first of its kind in the industry. To date, Huawei has partnered with many industry-leading carriers and tested Vectoring products on their live networks extensively.

4.2 Huawei E2E Vectoring Solution Huawei provides E2E Vectoring solutions covering the series Vectoring equipment at the CO, Vectoring CPEs, EMS, DSL expert system, sites with outdoor cabinets, and professional supporting services. The solutions, which enable smooth evolution, low cost, short time-to market and are also manageable and controllable, help carriers to build, operate, and maintain Vectoring networks.



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Figure 4-1 Huawei E2E Vectoring products and solution

Huawei's Vectoring solution has the most complete series of products in the industry. Figure 4-1 illustrates a typical example of Huawei E2E Vectoring products and solution.

The MA5603T, a large-capacity Vectoring product, provides built-in high-speed Vectoring buses and does not require extra space in an outdoor cabinet for interconnection of Vectoring cards. This device can be deployed to mainstream large-capability Vectoring sites.

The MA5616 is a medium-capacity Vectoring product that has the highest density in the industry. With a compact in size of 2 U height, 19-inch width and 300 mm depth, the MA5616 provides built-in high-speed Vectoring buses and supports 192 Vectoring lines, applying to mainstream medium-capability Vectoring sites. Compared with 3U or even larger-sized devices that support 192 Vectoring lines in the industry, the MA5616 saves installation space by at least 33%. It can be flexibly used in scenarios such as capacity expansion of backup power/battery, installation of baseband units (BBUs) for mobile base stations in the same cabinet, and installation of ODN components in the same cabinet. The MA5616 supports up to 384 Vectoring lines through cross-equipment interconnection, meeting the requirements of super-large-capacity Vectoring sites.

For small-capacity Vectoring sites in some remote areas or sites that have requirements for lesser coverage, shorter distance, and higher rate, Huawei provides a variety of flexible and customized Vectoring solutions:

With the following features, the MA5662 can be directly installed against a pole or on an outdoor wall in harsh environments, without the need of a cabinet: − Fully-enclosed structure − IP66 water-protection rating − Operating temperature ranging from –40°C to +70°C

The pizza-box MA5623A and MA5622A are small-sized (1 U height, 19-inch width, and 300 mm depth), maximally saving installation space. They apply to the following Vectoring deployment scenarios: − New deployment of super-small-capacity sites



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− Adaptations or re-shell of legacy outdoor cabinets or intermediate distribution frames (IDFs)

− Installation in basements or corridor cabinets

Vectoring Technology White Paper 5 Faster and More Powerful Copper

Access


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5 Faster and More Powerful Copper Access

Conforming to the trend of fiber-in and copper-out in the area of broadband access, high-speed copper access at a short distance facilitates the smooth evolution of access networks. In the near future, the access rate per twisted pair will exceed 1 Gbit/s, making copper access a supplement or substitute solution of fiber to the premise (FTTP).

Figure 5-1 Development of copper access technologies

As shown in Figure 5-1, multiple-input multiple-output (MIMO) that combines Vectoring and bonding increases the access rate by several times at the same distance using multiple twisted pairs. In actual deployments, two twisted pairs are commonly used. As an improvement of MIMO, the SuperMIMO technology can create N - 1 pairs of virtual lines based on any N pairs of physical lines to achieve the transmission capabilities of 2N - 1 pairs of lines, further increasing the access rate. MIMO and SuperMIMO apply to the multi-pair home-access scenarios, such as commercial user access, mobile backhaul, and backhaul of remote access sites. In the 3rd quarter of 2010, Huawei launched a SuperMIMO prototype, which uses four twisted pairs to achieve an access rate of 700 Mbit/s at a distance of 400 meters.

The G.fast technology focuses on the single-pair home-access scenarios (mainstream application scenarios). Using G.fast, an access rate (sum of upstream and downstream rates)

Vectoring Technology White Paper 5 Faster and More Powerful Copper

Access


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reaches 1 Gbit/s can be provided at a distance within 100 meters and the upstream and downstream rates can be assigned on demand. In addition, G.fast will be spectrum-compatible with traditional DSL technologies, and their spectra can coexist over the same bundle. Designed to have low power consumption, support reverse power supply from CPEs, and be adaptable to different environments, G.fast products can be flexibly deployed in various places such as manholes, poles, walls, or corridors. The application of such G.fast products can make full use of the "last 100 meters" copper home-access resources and cost-effectively resolve the issue where optical fibers cannot enter the buildings or homes. Standards setting organizations including the ITU-T are working on G.fast-related standards, which are expected to be finished in 2013. In the 4th quarter of 2011, Huawei launched the industry's first E2E Giga DSL prototype. This prototype complies with the G.fast standard draft and uses a single twisted pair to achieve an ultra-high access rate of 1 Gbit/s within 100 meters.

Vectoring Technology White Paper 6 Summary


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6 Summary

Ever since its birth in the 1990s, the rapid development of copper access technologies has enabled DSL to be a ubiquitous solution and become today's most widely used and most successful fixed broadband access technology. As the bandwidth requirements of the "last mile" access are booming, the inherent "reach vs. rate" contradiction, stability, reliability, and environment adaptability of DSL face ever-formidable challenges. To conform to the trend of smooth network evolution as "fiber-in and copper-out", the Vectoring technology has been developed. This technology uses various methods such as probe, compensation, and cancellation to achieve the best DSL performance in the "crosstalk-free" environment. Moreover, this technology much further exploits the potential of copper access networks and meets carriers’ requirements for smooth evolution, low costs, fast time-to-market, and is manageable and controllable O&M.

Mass applications and deployments of Vectoring still face several challenges, such as coexistence with traditional DSL technologies (especially VDSL2), adequate QoE guarantee, and comprehensive support. An E2E Vectoring solution covering the series Vectoring equipment at the CO, Vectoring CPEs, EMS, DSL expert system, sites with outdoor cabinets, and professional supporting services can address such challenges, meeting requirements for mass deployments.

The innovation of copper access technologies will continue. Vectoring working with other technologies such as bonding, virtual pairs, and orthogonal frequency division multiplexing (OFDM) can achieve an ultra-high access rate of 1 Gbit/s at a short distance, enabling a cost-effective and smooth evolution of fix broadband access networks.

Vectoring Technology White Paper A Acronyms and Abbreviations


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A Acronyms and Abbreviations

A

ACS auto-configuration server

ADSL asymmetric digital subscriber line

ATIS alliance for telecommunications industry solutions

B

BBF Broadband Forum

BBU base-band unit

C

CAPEX capital expenditure

CO central office

CPE customer premises equipment

D

DLM dynamic line management

DSE disorderly shutdown event

DSL digital subscriber line

DSLAM DSL access multiplexer

DSM dynamic spectrum management

E

EMS element management system

ETSI European Telecommunications Standards Institute



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FEXT far end crosstalk

F

FTTB fiber to the building

FTTC fiber to the cabinet

FTTCurb fiber to the curb

FTTEx fiber to the exchange

FTTH fiber to the home

FTTN fiber to the node

FTTP fiber to the premise

I

INP impulse noise protection

ITU International Telecommunication Union

L

LLU local loop unbundling

M

MIMO multiple-input multiple-output

N

NEXT near end crosstalk

O

ODN optical distribution network

OFDM orthogonal frequency division multiplexing

OLT optical line terminal

OPEX operational expenditure

OSS operating and supporting system

P

PSD power spectral density



21

Q

QoE quality of experience

R

RFI radio frequency interference

RT remote terminal

S

SHDSL single-pair high-speed DSL

SLU sub loop unbundling

SNR signal-to-noise ratio

SRA seamless rate adaptation

SSM static spectrum management

T

TCO total cost of ownership

TMS terminal management system

V

VDSL very-high-speed DSL

Vectoring Vectoring (self-FEXT cancellation for use with VDSL2 transceivers)

VLU virtual loop unbundling

VN virtual noise

Vectoring Technology White Paper B References


22

B References

[1]. ITU, Self-FEXT cancellation (Vectoring) for use with VDSL2 transceivers, 2010

[2]. ITU, Very high speed digital subscriber line transceivers 2 (VDSL2), 2006

[3]. Frank Defoort, Jan Verlinden, Introduction to DSL instabilities, April, 2008

[4]. IEEE, The ITU-T's New G.vector Stand Proliferates 100 Mb/s DSL, 2010

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