Tutorial: XG-PON

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

HUAWEI TECHNOLOGIES CO., LTD. Page 2


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



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


Now ~2010 ~2015


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



Physical split reductionPhysical split reduction

Central Office Splitter Cabinetp

OLT

OLT

OLT

OLT



“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



“Multiplexed G-PON” schemeMultiplexed G PON scheme

Central Office

ONU

ONUTx1Rx1

OLT Tx1Tx2Tx3Tx4

ONU

ONUTx2Rx2

Rx1Rx2Rx3Rx4

ONU

ONUTx3Rx3

OLT WDM ONU

ONUTx4Rx4




ONUBF



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




ONUBF



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




ONUBF



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



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


1.2G 2.5G Nx2.5G 10GNx1.2G


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



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



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



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?



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


1480 1500 1520 1540 1560 1580 1600 1620 1640


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


1480 1500 1520 1540 1560 1580 1600 1620 1640


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


1480 1500 1520 1540 1560 1580 1600 1620 1640


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


• This choice brought up an interesting system-level question…


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


XGPON2


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



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



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



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



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


Number of BWmap entries indicated by Blen


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



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



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



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



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



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



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



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



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



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


• All work will be finished by June 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


– Significant deployments in 2012


Documents

Tutorial: XG-PON