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  • 2010 Cisco and/or its affiliates. All rights reserved.

    DOCSIS 3.1An evolutionary approach to Gigabit Class DOCSISCABU EMEAR Marketing

    Nov. 14th 2012

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2

    Introduction

    Advanced* DOCSIS

    Case Study

    Advanced* DOCSIS vs EPOC

    * Standardization is underway at CableLabs under DOCSIS 3.1 reference

  • Cisco Confidential 2011 Cisco and/or its affiliates. All rights reserved. 3

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 4

    This year DOCSIS is 15 years old

    DOCSIS 1.0 I01 Spec released March 26, 1997.

    DOCSIS 3.1 An evolutionary approach to Gigabit-class DOCSIS

    For an era where MSOs will continue to push fiber deeper, potentially/eventually switch to all fiber for new build, but will do everything to maximize the return on earlier investments in coax plant.

    How the next 15 years will looklike!

    * Standardization is underway at CableLabs

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 5

    More services requires more IP bandwidth.

    How much bandwidth? What is really possible?

    Data as an

    IP Service

    Voice as an

    IP Service

    Video as an

    IP Service

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 6

    Example:

    300 video subs per SG, multicast for linear, unicast for VoD, 50% HD, 50% SD, VBR, MPEG4, 20 DOCSIS channels

    150 channels collapsing to 20 That is efficient!

    Source: HFC Capacity Planning for IP Video by Sangeeta Ramakrishnan, SCTE Expo 2011

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    Number of IP video subsper Service Group

    CBR

    VBR

    Video bandwidth will expand as new 4K and 8K formats are adopted.

    HSD will continue to grow and eventually may exceed SP video BW.

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 7

    Goals

    Allow DOCSIS over HFC to compete with FTTH solutions.

    Achieve 5+ Gbps in the downstream.

    Achieve 1+ Gbps in the upstream

    Backward compatibility story with DOCSIS 3.0, 2.0, & 1.1.

    Better spectral efficiency.

    Technology

    OFDM and LDPC

    Re-use SCDMA MAC concepts

    * Standardization is underway at CableLabs

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 8

    EPOC is EPON over Coax.

    EPOC and D3.1 will use the same PHY.

    DOCSIS (as it evolves) and EPOC are similar technologies but in different markets.

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 9

    , , and teamed together to help define and drive DOCSIS 3.1.

    The first output of this joint effort was a landmark white paper at NCTA 2012, both in terms of size and in terms of collaboration.

    182 pages

    83 Figures

    43 Tables

    10 recommendations

    7 areas of further study

    1. Introduction

    2. Cable Spectrum Analysis

    3. Solving Legacy Issues

    4. Coax Network Analysis

    5. HFC Optical Transport Options

    6. HFC Topology

    7. DOCSIS PHY

    (ATDMA, SCDMA, OFDM)

    8. DOCSIS MAC

    9. Network Capacity Analysis

    10.Network Capacity Migration

    11.Recommendations

    John T.

    Chapman

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 10

    Evolution of the Upstream/Downstream Split

    To get to a more Symmetrical Service Proposition (more in line with ETTH or xPON architecture)

    Extending the Frequency Spectrum

    In the first place to get maximum use on coax and passives in place (and found to easily support approx. 1.2 Ghz so 20% more than currently specd for us)

    MAC & PHY Layer

    To further Increase the Spectral Efficiency

    Maintaining Backwards Compatibility

    Avoid forklift upgrades and provide investment protection for earlier D1.1 or D2.0 CM, QAMs, Q.

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11

    DOCSIS 3.1 will introduce OFDM with LDPC.

    The target modulation is 1024-QAM.

    Up to 4K QAM will be specified

    Using the spectrum above current plant cut-offs(750 MHz to 1 GHz) requires an advanced

    PHY to support more complex modulation such as OFDM.

    OFDM will also be used below 1 GHz, and will likely supplant legacy QAM bandwidth over time.

    The initial push is to 1150 MHz. This may be possible without replacing taps. The long term push is 1.7 GHz, but this would require tap replacement.

    The DOCSIS 3.1 downstream deployment may occur before DOCSIS 3.1 upstream deployment.

    Improved FEC (Forward

    Error Correction) enables

    higher modulation at the

    same CNR performanceQ

    RF Spectrum Efficiency

    Improvement:

    ~ 25% with same CNR(8 10 bits / symbol, 1024QAM

    Equivalent)

    ~ 50% with improved CNR(8 12 bits / symbol, 4096QAM

    Equivalent)

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 12

    DOCSIS 3.1 upstream will use OFDMA with an LDPC FEC

    Target modulation is 256-QAM.

    Up to 4K will be speced.

    Existing spectrum will be shared between ATDMA/SCDMA and OFDM. New spectrum will be OFDM only.

    Frequency split options:

    The immediate goal is to maximize sub-split. (42/65 MHz)

    The short-term recommendation is mid-split. (85 MHz)

    The long-term recommendation is high-split. (~230 MHz)

    Mid-split triples upstream throughput and is available today with D3.0.

    DOCSIS 3.1 high-split provides 1 Gbps.

    Improved FEC (Forward

    Error Correction) enables

    higher modulation at the

    same CNR performanceQ

    RF Spectrum Efficiency

    Improvement:

    ~ 33% with same CNR(256QAM Equivalent)

    ~ 66% with improved CNR(1024QAM Equivalent)

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 13

    DOCSIS 3.0 DOCSIS 3.1

    Now Phase 1 Phase 2 Phase 3

    DS Range (MHz) 54 - 1002 108 - 1002 300 - 1152 500 - 1700

    DS QAM Level 256 256 1024* 1024*

    # DS Channels 8 24 142 200

    DS Capacity (bps) 300M 1G 7G 10G

    US Range (MHz) 5 - 42 5 - 85 5 - 230 5 - 400

    US QAM Level 64 64 256* 1024*

    # US Channels 4 12 33 60

    US Capacity (bps) 100M 300M 1G 2.5G

    Note: TBD values are underlined, Channels in quotes = Equivalent # of SC-QAMs * On OFDM PHY

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 14

    As extra measures to increase flexibility as well as system throughput DOCSIS AMP is likely to bring following news related to MAC & PHY:

    US PHY: Additional OFDMA* with new LDPC FEC**

    DS PHY: Additional OFDM with new LDPC FEC**

    Order of modulation: With a plan to investigate 4k QAM for OFDM, see table on previous slide that new standard targets supporting at least 1kQAM in both US and DS

    MAC: Likely for current SCDMA MAC functionality to be the basis for the new OFDMA MAC Layer

    Remark: Goal as set out for throughput is an increase of min. 50% in bits/Hz

    * Orthogonal Frequency Division Multiple Access

    ** Low Density Parity Check Forward Error Correction providing the equivalent of 5 to 6 dB performance improvement,

    in other words a system that runs today 64-QAM could run 256-QAM with new LDPC FEC

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 15

    DOCSIS 3.0 uses single carrier QAM (SC-QAM) in the downstream and upstream.

    Two sine waves, I and Q, each with separate amplitude and phase are added together to create symbol within a constellation.

    Each instance is referred to as a symbol.

    16-QAM is 4 bits per symbol

    256-QAM is 8 bits per symbol

    1024-QAM is 10 bits per symbol

    4096-QAM is 12 bits per symbol

    16384-QAM is 16 bits per symbol

    Example: 16-QAM

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 16

    OFDM is identical to coded OFDM (COFDM) and discrete multi-tone modulation (DMT)

    A frequency-division multiplexing scheme used as a digital multi-carrier modulation method using a large collection of very narrow QAM subcarriers.

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 17

    FEC = Forward Error Correction

    FEC adds redundant bits so that errored bits can be re-created.

    FEC requires an interleaver in order to be truly effective.

    LDPC = Low Density Parity Check

    Invented by Robert Gallager in 1960.

    Could not be implemented in HW until recently.

    LDPC is much more robust than Reed-Solomon.

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 18

    2 dB for FEC improvementsQ Reed Solomon versus LDPC

    1 dB for OFDM filter edge improvements versus Single Channel QAM

    1 dB for lowest common denominator for 12 KHz channel versus 6 MHz channel width

    Total = 4 dB equivalent improvement

    Remark: Assuming that most plants have 2 dB headroom for existing modulation depthQ there might be 2 modulation depth increases possible Q

    Resulting in 25-33% increase bits/Hz depending current DS/US constellation

  • 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidenti

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