tutorial: xg-pon
TRANSCRIPT
Tutorial: XG-PON
Frank J. EffenbergerOFC 2010OFC 2010
HUAWEI TECHNOLOGIES CO., LTD.
HUAWEI TECHNOLOGIES CO., LTD.Page 1
OWX4.pdf OSA / OFC/NFOEC 2010
978-1-55752-884-1/10/$26.00 ©2010 IEEE
OutlineOutline• Overview of the NGA candidates• Service requirements• Service requirements• Physical layer specifications • Protocol foundations• ONU management• Standardization plan
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OWX4.pdf OSA / OFC/NFOEC 2010
High level taxonomyHigh level taxonomy• There are many techniques in play in the industry• FSAN has attempted to structure these into “NGA1”• FSAN has attempted to structure these into NGA1
and “NGA2”• At the roughest level of approximation…• NGA1 = 10G total capacity and compatibility with
GPON– 10G serial transmission– CWDM multiplexing
• NGA2 = 40G total capacity and compatibility not necessaryy– True WDM PON, with 1G per wavelength– Hybrid PON, with four 10G wavelengths
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OWX4.pdf OSA / OFC/NFOEC 2010
NG-PON technology roadmapNG PON technology roadmapNG-PON2
E.g. Higher-rate TDM,DWDM, CDM,
OFDM etc
Component R&D to enable NG-PON2
“Coexistence” enables gradual
i ti i th
OFDM, etc.
NG-PON1 incl. long-reach optionC
apac
ity
WDM option to enable to overlay/multiple
XGPONs
migration in the same ODN.
g
Splitter for NG-PON2(power splitter or
G-PON
1G EPON
XG-PON(Up: 2.5G or 10G,
Down: 10G)
Power splitter deployed for Giga PON(no replacement / no addition)
(po e sp tte osomething new)
1G-EPON
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Now ~2010 ~2015
OWX4.pdf OSA / OFC/NFOEC 2010
NGA1 capacity increase Candidate technologiesCandidate technologies• Physical split reduction [No new technology]
• WDM bidirectional split reduction
• WDM downstream-only split reduction
• XG-PON1: 10G down, Nx2.5G up
• XG-PON2: 10G symmetric y
• Reach enhanced versions of the XG-PONs
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OWX4.pdf OSA / OFC/NFOEC 2010
Physical split reductionPhysical split reduction
Central Office Splitter Cabinetp
OLT
OLT
OLT
OLT
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OWX4.pdf OSA / OFC/NFOEC 2010
“Stacked G-PON” schemeStacked G PON scheme
Central Office
ONUBF
OLT Tx1Tx2Tx3Tx4
ONUBF
Rx ONUBF
OLT WDM
ONUBF
Equipment and Facilities initially deployed
Equipment and Facilities deployed as part of upgrade
Equipment and Facilities removed as part of upgrade
ONUBF
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OWX4.pdf OSA / OFC/NFOEC 2010
“Multiplexed G-PON” schemeMultiplexed G PON scheme
Central Office
ONU
ONUTx1Rx1
OLT Tx1Tx2Tx3Tx4
ONU
ONUTx2Rx2
Rx1Rx2Rx3Rx4
ONU
ONUTx3Rx3
OLT WDM ONU
ONUTx4Rx4
Equipment and Facilities initially deployed
Equipment and Facilities deployed as part of upgrade
Equipment and Facilities removed as part of upgrade
ONUBF
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OWX4.pdf OSA / OFC/NFOEC 2010
10/Nx2.5G Scheme “XG-PON1”10/Nx2.5G Scheme XG PON1
Central Office
ONU
ONUTx1Rx
OLT10G
ONU
ONUTx2Rx
Rx1Rx2Rx3Rx4
ONU
ONUTx3Rx
OLT WDM ONU
ONUTx4Rx
Equipment and Facilities initially deployed
Equipment and Facilities deployed as part of upgrade
Equipment and Facilities removed as part of upgrade
ONUBF
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OWX4.pdf OSA / OFC/NFOEC 2010
10 Symmetric Scheme “XG-PON2”10 Symmetric Scheme XG PON2
Central Office
ONU
ONUTxRx
OLT10G Tx
ONU
ONUTxRx
10G RxONU
ONUTxRx
OLT WDM ONU
ONUTxRx
Equipment and Facilities initially deployed
Equipment and Facilities deployed as part of upgrade
Equipment and Facilities removed as part of upgrade
ONUBF
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OWX4.pdf OSA / OFC/NFOEC 2010
Reach enhanced XG-PONsReach enhanced XG PONs
• Same topology as ‘conventional’ XG-PON
• Use more advanced laser source at the ONU– Narrow wavelength band (~0.5 nm) via cooled sourceg ( )
– C-band wavelength choice
• Employ EDFA at every OLT port to achieve• Employ EDFA at every OLT port to achieve– Increased power budget
Increased split ratio– Increased split ratio
– Increased distance
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OWX4.pdf OSA / OFC/NFOEC 2010
The selection of XG-PON1The selection of XG PON1
Downstream
Future Systems (NGA2)
Downstream
10G 10/1G EPON
10/10G EPON
XGPON1(XGPON2)
Nx2.5G MuxedGPON
StackedGPON
2.5G GPONTurbo EPON
Acceptablebandwidth
Upstream1G EPON
asymmetry
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1.2G 2.5G Nx2.5G 10GNx1.2G
OWX4.pdf OSA / OFC/NFOEC 2010
Service requirementsService requirements
• Full service access network
• Residential – FTTH, FTTB, FTTN
POTS VoIP Internet access video | Ethernet MoCA VDSL2– POTS, VoIP, Internet access, video | Ethernet, MoCA, VDSL2
• Business – Small and medium businessesSmall and medium businesses
– Metro ethernet (Eline, E-LAN), T1/E1 PWE3
• Infrastructure– Wireless Basestations, picocells, etc.
– L2 connectivity, CPRI
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OWX4.pdf OSA / OFC/NFOEC 2010
Network requirementsNetwork requirements
• Compatible with existing systems on common ODN
– G-PON (1490 / 1310nm)
– Video overlay (1555nm)
D t 10 Gb/ i l ( l d b l )• Downstream 10 Gb/s nominal (payload can be less)
• Upstream 2.5 Gb/s nominal
• Maximum fiber distance: 20km, with options of 40km
– Logical capability of 60km built-in, to support mid-span RE
• Split ratio up to 1:256
• Loss budgets: 29dB and 31 dB
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OWX4.pdf OSA / OFC/NFOEC 2010
Major new features for XG-PON1Major new features for XG PON1
• Security– Automatic identification (for provisioning)
– ONU and OLT authentication
– Information privacy (downstream and perhaps upstream)
• Power saving– Primary goal: extension of battery life / minimizing size, cost
• Shutting off non-essential services during outageSecondary goal: reduction of power use at all times– Secondary goal: reduction of power use at all times
• Putting various parts of ONU to sleep, but without noticable service degradation
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OWX4.pdf OSA / OFC/NFOEC 2010
Physical layer specificationsPhysical layer specifications
• Spectrum plan
– How can we fit two PONs and video onto a single fiber, cheaply?
• Line rate and code
– How fast, exactly?
• Power budgets• Power budgets
– Can the real ODN please stand up?
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OWX4.pdf OSA / OFC/NFOEC 2010
Designing the spectrum plan: Starting pointDesigning the spectrum plan: Starting point
GPONp
1260 1280 1300 1320 1340 1360
up
GPONd
VidOGuard Guard
1480 1500 1520 1540 1560 1580 1600 1620 1640
down Ovrband band
GPONdown Guard
band
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1480 1500 1520 1540 1560 1580 1600 1620 1640
OWX4.pdf OSA / OFC/NFOEC 2010
All the candidates line upAll the candidates line up
GPONp
XGPON1Up Ch D
XGPON1Up Ch E
1260 1280 1300 1320 1340 1360
up Up Ch. DUp Ch. E
XGDn
XGPON1Up Ch AGuardGPON
dVidOGuard Guard
XGPON1
Up Dn Up Ch. Aband
1480 1500 1520 1540 1560 1580 1600 1620 1640
down Ovrband bandUp
Ch. C
XGDn
XGPON1Up Ch. B
GPONdown Guard
bandGuardband
XGPON1Up Ch. AGuard
band
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1480 1500 1520 1540 1560 1580 1600 1620 1640
OWX4.pdf OSA / OFC/NFOEC 2010
The basic XG-PON1 spectrumThe basic XG PON1 spectrum
GPONp
XGPON1Up Ch D
XGPON1Up Ch E
1260 1280 1300 1320 1340 1360
up Up Ch. DUp Ch. E
XGDn
XGPON1Up Ch AGuardGPON
dVidOGuard Guard
XGPON1
Up Dn Up Ch. Aband
1480 1500 1520 1540 1560 1580 1600 1620 1640
down Ovrband bandUp
Ch. C
XGDn
XGPON1Up Ch. B
GPONdown Guard
bandGuardband
XGPON1Up Ch. AGuard
band
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1480 1500 1520 1540 1560 1580 1600 1620 1640
OWX4.pdf OSA / OFC/NFOEC 2010
Line rate and CodeLine rate and Code
• The exact speed and code need to be selected
• Over the course of 2009, many options were considered
• Downstream options:
– SDH/SONET 9.95328 Gb/s, NRZ scrambled
– Ethernet-like 10.31184 Gb/s, 64b66b, scrambled
• Upstream options:
– Ethernet-like 3.125 Gb/s, 9b10b coded
Eth t lik 2 57796 Gb/ NRZ bl d– Ethernet-like 2.57796 Gb/s, NRZ scrambled
– SDH/SONET 2.48832 Gb/s, NRZ scrambled
• This choice brought up an interesting system level question
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• This choice brought up an interesting system-level question…
OWX4.pdf OSA / OFC/NFOEC 2010
PON Coexistence .6G/.15G
Coexistence pathways:1. IEEE system2 ITU SystemPON Coexistence
1G/1G
.6G/.15GBPON
2. ITU System3. ITU-to-IEEE system4. EPON to XG-PON5 10G to XG PON1G/1G
EPON 2.5G/1GGPON
5. 10G-to-XG-PON
10G/1GEPONEPON 10G/2.5G
XGPON1
10G/10GEPON 10G/10G
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XGPON2
OWX4.pdf OSA / OFC/NFOEC 2010
Coexistence CrisisCoexistence Crisis
• If we want all compatibility pathways, then the 10G downstream must use a common line rate / code – This would be 64b66b running at ~10.3125 Gb/s
• However, operators consider this unneeded– One upgrade to Generation 4 equipment is enough!
– It is highly unlikely that 10/1 would be upgraded to 10/2.5, or 10/2.5
to 10/10
• Thus, XG-PON1 can use its own line rate / code – NRZ, 9.95328 Gb/s downstream, 2.48832 Gb/s upstream
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OWX4.pdf OSA / OFC/NFOEC 2010
Power budgets, and ODNs of the worldPower budgets, and ODNs of the world
• The “best practice” budget for G-PON is 28dB
– The simple answer would be that XG-PON should follow suit
• Unfortunately, life is not so simple
– Many real deployments have a bigger budget than this
– The WDM1 filter will have extra loss in the XG-PON path
The fiber loss at 1270nm will be slightly higher than 1310nm– The fiber loss at 1270nm will be slightly higher than 1310nm
• As a result, two “nominal” budgets were selected
29 dB fits deployments using B+ G PON– 29 dB – fits deployments using B+ G-PON
– 31 dB – fits deployments using B++ G-PON
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OWX4.pdf OSA / OFC/NFOEC 2010
Downstream budgetsDownstream budgets
Nominal-1 Nominal-2 Nominal-2 Extended
APD PIN (APD)
Tx max +6.0 +8.0 +12.5 +10.0
Tx min +2.0 +4.0 +10.5 +6.0~7.0*
Loss 29 0 31 0 31 0 33 0Loss 29.0 31.0 31.0 33.0
OPP 1 1 1 1~2*
Rx Sen (1e-3) -28.0 -28.0 -21.5 -28.0
Rx Over -8.0 -8.0 -3.5 -8.0
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Upstream budgetsUpstream budgets
Nominal 1 Nominal 2 ExtendedNominal-1 Nominal-2 Extended
Tx max +7.0 +7.0 +7.0
Tx min +2.0 +2.0 +2.0
Loss 29.0 31.0 33.0
OPP 0.5 0.5 0.5
Rx Sen (1e-4) -27.5 -29.5 -31.5( )
Rx Over -7.0 -9.0 -11.0
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Protocol foundations (1): Downstr. FrameProtocol foundations (1): Downstr. FramePCBd XGTC Payload
4*K bytes
PLOAM PLOAM Other Payload …4*N bytes 4*N bytes
…
Psync
4 bytes
Ident
4 bytes
Upstream BWmap
8*L bytes
BIP
4 bytes
Plend
4 bytes
Number of PLOAMs indicated by Alen
Number of BWmap entries indicated byBlen CRCAlen
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Number of BWmap entries indicated by Blen
OWX4.pdf OSA / OFC/NFOEC 2010
Framing Structure and FECFraming Structure and FEC
• Defined by 125 ms periodic frame pattern – 155,520 bytes in each frame
• Strong FEC code: RS(248,216)g ( , )– Operates at ~1e-3 BER
• 627 codewords per frame with 24 bytes remaining• 627 codewords per frame, with 24 bytes remaining
• 24 byte remnant used for framing pattern and other
functions
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OWX4.pdf OSA / OFC/NFOEC 2010
Bandwidth MapBandwidth Map
• Each entry is 8 bytes StartTimeAlloc-ID GrantSize HECFlags
• Alloc-ID: Basic unit of bandwidth allocation
• Start Time: The post-FEC start time of the allocation
• Grant Size: The number of pre-FEC payload words
• Flags: Signals the transmission of
– Dynamic Bandwidth Report
– Requested PLOAM
– Upstream burst profile to use
• HEC: Capable of correcting 2 errors and detecting 3
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OWX4.pdf OSA / OFC/NFOEC 2010
Downstream PLOAM channelDownstream PLOAM channel
• PLOAM message made larger to accept all payloads
• Multiple PLOAMs can be sent per frame– This can reduce latency of PLOAM channel y
– May be used to signal power saving modes
• Limits on the frequency of messages to any ONU• Limits on the frequency of messages to any ONU
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OWX4.pdf OSA / OFC/NFOEC 2010
Protocol foundations (2): Upstream BurstProtocol foundations (2): Upstream Burst
Guard XGTC PayloadPreamble Delimiter Burst Header DBRuPLOAM BIPtime 4*Q bytes8 bytes 4 bytes
4*P bytes
32 bytes 4 bytes
0x0000 ONU ID Fl HEC0010x0000or
0x0020
ONU-ID
2 bytes
Flags
2 bytes
HEC
13 bits
001
3 b
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Burst ProfilesBurst Profiles
• Different bursts need different physical parameters
– Ranging is more difficult than normal operation
– Far ONUs need FEC, but close ONUs do not
Th OLT ifi l b t fil• The OLT specifies several burst profiles:
– Preamble pattern and length
Delimiter pattern– Delimiter pattern
– FEC on / off
• The OLT specifies the burst profile in each allocationThe OLT specifies the burst profile in each allocation
– ONU simply follows the instructions
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Burst HeaderBurst Header
• ONU sometimes must send a PLOAM quickly– The “dying gasp” message
– Protection switching
• Rather than wait for OLT to request a transmission,
the ONU can send an autonomous PLOAMthe ONU can send an autonomous PLOAM
• Additionally, very fast/short messages can be
i l d i th Fl fi ldsignaled using the Flags field
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Protocol foundations (3)Protocol foundations (3)
XGEM Header XGEM Payload
8 bytes 4*U bytes
Payload with 0~3 byte padding
PLI Port-ID
2 bytes
Option CRC/HECKey index PTI
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XGEM featuresXGEM features
• Payload length: Up to 16K byte PDUs
• Fragmentation supported
• Encryption key index to make on-the-fly key• Encryption key index to make on-the-fly key
switching simpler
• Option field, leaving space for future enhancements
• HEC, corrects 2 errors, detects 3 errors
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ONU managementONU management
• ONU management follows the long tradition of OMCI
from B-PON and G-PON
• Integrated full service FCAPS capabilitiesIntegrated full service FCAPS capabilities
• Yes, it is complex, but that is what it takes!
• Some liberalization of the message formats– Larger PDUs, for enhanced efficiency
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OWX4.pdf OSA / OFC/NFOEC 2010
Standardization PlanStandardization Plan
• FSAN and ITU-T (Q2/15) are working together to
complete the G.987 series– G.987: Common definitions and acronyms: AAP
– G.987.1: System requirements: AAP
– G.987.2: Physical media dependent specification: AAP
– G.987.3: Transmission covergence specification: June 2010
• The ONU management and configuration interfaceThe ONU management and configuration interface
(OMCI) will be generalized in the G.988 document
All k ill b fi i h d b J 2010
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• All work will be finished by June 2010
OWX4.pdf OSA / OFC/NFOEC 2010
ConclusionsConclusions
• FSAN / ITU-T has thought long and hard over the next PONCoe istence ith c rrent deplo ment is ke– Coexistence with current deployment is key
– Cost effective bandwidth is the watch-word
• XG-PON1 provides the a good blend of characteristicsp g– Compatibility with G-PON and GE-PON
– Higher bandwidth, with acceptable asymmetry
– High loss budget capabilities
– Low cost for equipment
• TimelineTimeline – Standard completed by 2010
– First trial expected by year’s end
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– Significant deployments in 2012
OWX4.pdf OSA / OFC/NFOEC 2010