PON requirements and evolutionEvolution of FTTH technologies and their standardization NG PON

Ed Harstead

Lead Technologist, Chief Technology OfficeFixed Networks DivisionAlcatel-Lucent

José Salgado

Network Systems Development DirectorPT Inovação

2

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

Sustained bandwidth demand requirement for FTTHAn upper bound forecast for a single high-end user

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

2011 (Conservative)

SD 2.2 Mb/s

HD 720p 8.0 Mb/s

HD 1080p 13.6 Mb/s

3D 1.4 x 2D

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

0

20

40

60

80

100

120

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Band

width dem

and (M

b/s)

15% YoY(5-year doubling)

15% YoY upper bound

3D 4320p60

4320p60

3D 2160p60

2160p60

3D 1080p

1080p60

3D 720p60

720p60

SD

from “Future FTTH bandwidth demands favor TDM PONs”, Harstead, Sharpe, IEEE Comm Mag, Nov 2012

3

What FTTH technologies can satisfy that requirement?

0

2

4

6

8

10

Band

wid

th (

Gb/

s)

Upper bound, streaming video BW demand, 32 video subs

0

2

4

6

8

10

Band

wid

th (

Gb/

s)

GPON bandwidth supply

Upper bound, streaming video BW demand, 32 video subs

GPON

0

2

4

6

8

10

Band

wid

th (

Gb/

s)

Upper bound, streaming video BW demand, 64 video subs

GPON bandwidth supply

Upper bound, streaming video BW demand, 32 video subs

GPON

0

2

4

6

8

10

Band

wid

th (

Gb/

s)

10G PON bandwidth supply

Upper bound, streaming video BW demand, 64 video subs

GPON bandwidth supply

Upper bound, streaming video BW demand, 32 video subs

10G PON

GPON

0

2

4

6

8

10

Band

wid

th (

Gb/

s)

10G PON bandwidth supply

Upper bound, streaming video BW demand, 64 video subs

GPON bandwidth supply

Upper bound, streaming video BW demand, 32 video subs

Headroom for bursty services

10G PON

GPON

10G PON bandwidth supply

Upper bound, streaming video BW demand, 64 video subs

GPON bandwidth supply

Upper bound, streaming video BW demand, 32 video subs

Worst case model assumptions:

• All subscribers are high-end users

• No native multicasting on the PON

• Only 2:1 concentration on PON

Bandwidth headroom

1 Gb/s PTP can of course support. What about PON?

from “Future FTTH bandwidth demands favor TDM PONs”, Harstead, Sharpe, IEEE Comm Mag, Nov 2012

4

What about burst bandwidth demand?

0

1000

2000

3000

4000

5000

6000

0 10 20 30 40 50 60

Web

 page load

 time (m

s)

Advertised Speed (Mb/s)

Web page load  time vs. advertised speed

Steep performance improvement from 2 to 10 Mb/s.

But >10 Mb/s saturation bandwidth, there is virtually no performance gain.  

Plotted from raw data available at: http://www.fcc.gov/measuring‐broadband‐america/2012/july

5

Above saturation bandwidth, speed depends on latency, not bandwidth

0

500

1000

1500

2000

0 20 40 60

Web

 page load

 time (m

s)

Average roundtrip latency (ms)

Web page load  time vs. latency(Advertised speed > 10 Mb/s)

All

Cable average

FTTN average

FTTN‐G.INP (est.)

PON FTTH average

All (linear approx.)Every 1 ms latency

reduction leverages 20 ms in performance

improvement

Plotted from raw data available at: http://www.fcc.gov/measuring‐broadband‐america/2012/july

6

FTTH: cannot optimize for bandwidth alone

Deeper dive: Transmission Control Protocol (TCP)

• TCP provides reliable connections on the Internet• It is used for:− web browsing − email− file transfers − adapative streaming video

• TCP throughput is inversely proportional to latency • TCP “saturation bandwidth” is inversely proportional

to latency• TCP performance improvements are pursued by

Google, Bell Labs, and others.

• TCP throughput is (to 1st order) inversely proportional to latency!

• To reap the benefits of FTTH, operators must also optimize their network for low latency

• Bandwidth >100M is only useful for very high speed transfer of very large files.

• Reducing latency also important for cloud gaming response and mobile backhaul

7

Capacity

NG‐PON1 

2010 2015

PON standards evolution

NG‐PON2DS: 40G

US: 10G/40G

EPON

10GE‐PONDS:10G

US:1 or 10G

GPON

XG‐PON2DS: 10GUS: 10G

XG‐PON1DS: 10GUS: 2.5G

IEEE

ITU‐T

• Base system: 40G downstream, 10G upstream– 4 channels in each direction– Compatible with G-PON, XG-PON, and RF video overlay– 20km @ 1:64 split ratio fully passive plant capable

• Optional extra capabilities– 8 channels in each direction – 10G upstream – DWDM overlay (will allow further capacity expansion: business,

MBH, etc)

• Standardization is expected to complete July 2013

Effenberger, ITU‐IEEE WS, Sept2012

NG-PON2 base requirements

9

Key Features:• Builds on XG‐PON1• Uses splitter based PON•Up to 80Gbit/s (total throughput)• Coexistance with GPON Networks

NG-PON2 OLT

BM Rx 1

Tx λ1

Logic

NG-PON2 ONU 1.1

Logic

Laser

Rx  

AW

GA

WGTx λ2

Tx λ8

…

BM Rx 2

BM Rx 8

…

1:N NG-PON2 ONU 2.1

Logic

Laser

Rx  

NG-PON2 ONU n.1

Logic

Laser

Rx  

• Challenges

− Tunable Receivers and Transmitters at ONU

− Spectrum allocation

Modified from Effenberger, ITU‐IEEE WS, Sept2012

TWDM PON architecture: Wavelength-stacked TDM PONs

Coexistence scenario allows new clients/services over existing ODN

Splitter

Mobile Backhaul

Business and Enterprise(VPN L3, Access to the Internet)

ONT

ONT

Residential(2Play and 3Play services)

Local Community (Schools, Police Stations, …)

ONT

ONT

NG‐PON2 should be capable to replace GPON in all its extent.

OLT NG-PON2

λTx, λRx

CEx

CoexistenceElement

λ1, λ5

RF Video HE

OLT GPON

OTDR

OLT XG-PON

λ2, λ6λ3, λ7λ4, λ8

Support of mix technologies over same ODN

11

Stacking different line speeds, and pay-as-you-grow

Challenges and critical points

• The need for speed– High and scalable BW provided by NG-PON2 allows to implement

Fixed Mobile converged networks

• Central office consolidation– NG-PON2 offers the possibility to cover wide areas hence allowing

consolidation of access and metro functions

• Main challenges– Use of tunable transmitters and receivers at ONUs needed by TWDM

technology– Coexistence scenarios

TWDM PON implementationWavelength-set division multiplexing (WSDM)

• The narrow tuning range requirements of TWDM PON lead to the possibility of low cost tunable transmitters and receivers in the ONU.

• In particular, WSDM allows for a very low cost tunable transmitter

1:N

Rx 1

Rx 4

Rx 2

Rx 3

Tunable Tx

λ1 λ2 λ3 λ4 λ5 λ6 λ7 λ8 λ9 λ10 λ11 λ12 λ13 λ14 λ15 λ16 ...

Cyclic‐AWG

λ1 λ2 λ3 λ4 λ5 λ6 λ7 λ8 λ9 λ10 λ11 λ12 λ13 λ14 ...

λ1 λ2 λ3 λ4 λ5 λ6 λ7 λ8 λ9 λ10 λ11 λ12 λ13...

λ1 λ2 λ3 λ4 λ5 λ6 λ7 λ8 λ9 λ10 λ11 λ12 λ13 λ14 λ15 ...

λ1 λ2 λ3 λ4 λ5 λ6 λ7 λ8 λ9 λ10 λ11 λ12 λ13 λ14 λ15 λ16 ...

OLT

ONU

Splitter

Upstreampath

4‐wavelength system

14

OFDMPON

UDWDM UDWDM PON

WDM and UDWDM PON

Num

ber o

f Wavelen

gths

A-PON B‐PON G-PON XG‐PON

XLG‐PON1

4

16

155M 622M 2.5G 10G 40G

512

1024

TWDMPON

Modified from Effenberger, ITU‐IEEE WS, Sept2012

ITU-T PON standards evolution: A-PON to NG-PON2 and beyond

Thank you for your attention!

www.ftthcouncil.eu