Tu1A1 ECOC2008 0831 paper

TUTORIAL

Trends in optical access and in-building networks

T. Koonen COBRA - TU Eindhoven

The Netherlands

Abstract As users require ever more speed, variety and personalization in ICT services, the capacity and versatility of access networks needs to be expanded. The first generation of point-to-point and of point-to-multipoint time-multiplexed passive optical networks (PON) is being installed. More powerful wavelength-multiplexed and flexible hybrid wavelength-time multiplexed solutions are coming up. Radio-over-fibre techniques create pico-cells for high-bandwidth wireless services. Next to bringing the bandwidth luxury to the doorstep, it must be distributed inside the user’s home. By advanced signal processing techniques, high-capacity wired and wireless services are jointly distributed in a low-cost converged in-building network using multimode (plastic) optical fibre.

T. Koonen

Ton (A.M.J.) Koonen was with Bell Laboratories of Lucent Technologies for more than 20 years, as technical manager of applied research in broadband systems up to end 2000. From 1991 to 2000, he also was a part-time professor at Twente University. Since 2001, he is full professor in the COBRA Institute at Eindhoven University of Technology, and chair of the Electro-Optical Communication Systems group since 2004. He is a Bell Labs Fellow since 1998, IEEE Fellow since 2007, and elected member of the LEOS Board of Governors since 2007. Ton’s research interests include broadband fibre access and in-building networks, radio-over-fibre networks, and optical packet-routing networks. He has led and contributed to many European and Dutch projects in these areas.

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ECOC 2008, 21-25 September 2008, Brussels, Belgium

978-1-4244-2229-6/08/$25.00 ©2008 IEEE

Extended Abstract As the thirst of users keeps increasing for higher capacity, more diversity and more personalization of services, the capacity and versatility of access networks needs to be expanded. Next to fast internet and high-definition video services, peer-to-peer file exchange and multi-party video-rich gaming are driving the need for bandwidth. Optical fibre is coming in, in order to relieve the shortcomings of the copper network, and also is able to outperform the power consumption of today’s electronic solutions. Moreover, by exploiting the wavelength domain optical fibre is uniquely capable of integrating services with widely differing characteristics independent from each other into a single infrastructure.

First-generation fibre-to-the-home (FTTH) networks are being installed in point-to-point (P2P) and point-to-multipoint (P2MP) time-multiplexed passive optical network (PON) architectures. As a major part of the infrastructure is shared among the users, the PON architecture may offer lower installation and maintenance costs beyond a certain reach and number of users, but it requires a well-tailored medium access control protocol for fair sharing of the capacity among them. Most popular nowadays is the time-division multiple access (TDMA) protocol, where functions can be readily implemented with digital electronics. It is being used in BPON (ATM-based, up to 622 Mbit/s symmetrically), GPON (Gigabit PON, with speeds up to 2.5 Gbit/s, for ATM and also Ethernet packets plus native TDM), and EPON (Ethernet PON, optimized for variable-length Ethernet packets). Alternatively, one may consider Subcarrier Multiple Access (SCMA), requiring more costly RF electronics, or Optical Code Division Multiple Access (OCDMA), requiring more costly optical spectrum slicing filters. Gaining popularity is Wavelength Division Multiple Access (WDMA), where each user on the WDM-PON gets an individual pair of wavelengths for up- and downstream communication, thus in effect getting a P2P link (with its advantage of easy per-user upgrading) on a P2MP physical infrastructure. With so-called ‘colour-less’ optical network units (ONUs) at the user side, using for instance reflective semiconductor optical amplifiers, more expensive wavelength-specific ONU solutions are avoided; this reduces the costs of the WDM-PON. Hybrid WDM-TDM PON networks can combine the large multiple-channel capacity offered by WDMA with the dynamic bandwidth sharing enabled by TDMA. Notably for PONs with larger ONU numbers and longer reach such hybrid schemes are attractive. Augmented with dynamic optical routing, capacity-on-demand with remarkably reduced congestion probability can be provided, while also improving the efficiency by which the resources installed in the local exchange are used.

For supporting broadband wireless services in fixed wireless access, radio over fibre (RoF) techniques enable to consolidate the microwave signal generation and modulation functions in a single site, which facilitates upgrading and more comprehensive radio schemes. Advanced optical techniques generate extremely pure microwave carriers, and thus enable comprehensive radio signal constellations for high-capacity wireless data links. Dispersion-tolerant RoF techniques support long-reach operation, and link switching in reconfigurable architectures.

Next to bringing the luxury of a high bandwidth to the doorstep by means of FTTH, it must be distributed inside the user’s home. As cost is an even more important factor there, easy-to-install large-core multimode (plastic) optical fibre is an attractive medium for implementing a converged single infrastructure which can support wired as well as wireless broadband services. Comprehensive signal modulation formats, such as multi-tone quadrature amplitude modulation schemes, enable to transport high-capacity data wired services via the highly-dispersive fibre infrastructure. Dispersion-robust RoF techniques can support pico-cell radio cell architectures. Using optical routing techniques, such cells may be dynamically merged into reconfigurable wireless private networks, in response to changing traffic patterns.

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amjk 1

COBRACOBRA

Trends in Optical Access and Trends in Optical Access and InIn--Building NetworksBuilding Networks

Ton Koonen

COBRA Institute dept. Electrical Engineering

Eindhoven University of Technologye-mail: [email protected]

Tutorial We.2A.1, ECOC 2008, Brussels, 24 Sep. 2008

COBRACOBRA

amjk 2

COBRACOBRAOutlineOutline

BB access trends

PON multiple access techniques(TDMA, SCMA, OCDMA, WDMA)

TDM-PON solutions (BPON, EPON, GPON)

WDM-PON

WDM-TDM reconfigurable optical access

Radio over fibre

BB in-home optical network techniques

Concluding remarks

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COBRACOBRATelecommunication networksTelecommunication networks

Global Network

Metropolitan/RegionalArea Optical Network

Client/AccessNetworks

variety of mediahigh traffic dynamicscost-conscioususer mobility

ultra-long reachultra-high capacity

ultra-fast packet routing

Home / Enterprise

Cable modemNetworks

FTTH Mobile

SDH/SONET

ISPGigabitEthernet

Cable

FTTB

IP/ATM

fibre

IP

Fixed WirelessAccess

TP

WLAN

Triple Play

amjk 4

COBRACOBRAHomo ZappiensHomo Zappiens

[Wim Veen - TU Delft]

HomoHomo ZappiensZappienshighhigh speedspeedmultimulti taskingtaskingiconiciconic skillsskillsconnectedconnectedlearninglearning byby playingplayinginstantinstant payoffpayofffantasyfantasytechnologytechnology asas friendfriend

HomoHomo SapiensSapiensconventionalconventional speedspeedmono taskingmono taskingreading skillsreading skillsstand alonestand aloneseparating learning and playingseparating learning and playingpatiencepatiencerealityrealitytechnology as foetechnology as foe

fast growing need for broadband capacity at home and in access; broadband internet traffic, packet-based

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COBRACOBRABB penetration ratiosBB penetration ratios

Japan: 10.52 M FTTH (13.48 M DSL ) connections in Dec. 2007

0

5

10

15

20

25

30

35

40

Denmark

Netherlan

ds

Iceland

Norway

Switzerl

and

Finlan

dKore

a

Sweden

Luxe

mbourg

Canada

United King

dom

Belgium

France

German

y

United Stat

es

Austra

liaJa

pan

Austria

NewZea

land

Irelan

dSpa

inIta

ly

Czech

Rep

ublic

Portug

al

Hungary

Greece

Poland

Slovak R

epub

lic

Turkey

Mexico

Source: OECD

DSL Cable Fibre/LAN Other

OECD Broadband subscribers per 100 inhabitants, by technology, Dec. 2007

OECD average

amjk 6

COBRACOBRAFTTH as fraction of broadband connectionsFTTH as fraction of broadband connections

Source : OECD

0% 5% 10% 15% 20% 25% 30% 35% 40% 45%

Ireland

Netherlands

Iceland

Italy

United States

Czech Republic

Norway

OECD

Denmark

Slovak Republic

Sweden

Korea

Japan

Percentage of fibre connections in total broadband subscriptions, Dec. 2007

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COBRACOBRAFTTH topologiesFTTH topologies

ANLEX

P2P

individual upgradingcheap Ethernet P2P transceiversfibre-rich

ANLEXOptical power

splitter/combiner

P2MP – passive star

“ PON – Passive Optical Network ”

fibre-sharingminimum maintenanceeasy overlay for broadcast serviceslower CAPEX* than P2P (for longer feeders and/or more users)

ANLEXactivenode

P2MP – active star

fibre-sharingremote poweringFTTC, FWA

* CAPEX – CAPital EXpenditure

amjk 8

COBRACOBRACosts P2P Costs P2P vsvs P2MP (CAPEX view)P2MP (CAPEX view)

number of ONUs N1 < N2

fixed costs C: OLT, ONUs, splitter

Syst

emin

stal

latio

n co

sts

Distance from OLT

P2P, N2>N1

P2P, N1

0

CP2P, N2

CP2P, N1

System installation costs (CAPEX):FO cable + passive splitterFO terminal equipmentw/o ducting (same P2MP ducting for P2MP and P2P)

L OPEX* view:repair of feeder cable break easier in P2MP than in P2P

* OPEX – OPerational EXpenditure

for L< L0 ,P2P cheaper than P2MPfor high N, P2MP may always be cheaper

P2MP, N1

L0(N1)

P2MP, N2

CP2MP, N1

CP2MP, N2

cost break-even at cable length L0 ; L0 dep. on N

[A.M.J. Koonen, Proc. IEEE, May 2006]

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BB access penetration



WDM-PON

Dynamically reconfigurable optical access

Radio over fibre

Concluding remarks

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COBRACOBRAMultiple Access Multiple Access –– Time DivisionTime Division

time-interleaving upstream packets (using request/grant protocol, ONU sends packet in timeslot granted by headend station; may send multiple packets when multiple grants)statistical multiplexing gainrequires time synchronisation dependency between data channels from ONUsburst-mode receiver in headend stationused in BPON, EPON, and GPON

t

Rxtimedemux

TDMA upstream:

[A.M.J. Koonen, Proc. IEEE, May 2006]

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COBRACOBRAMultiple Access Multiple Access -- SubCarrierSubCarrier

fully independent data channelsno time synchronisation required, no multiplexing gainrequires RF analog OE functions at OLT and ONUs expensivenodes may send at nominally same wavelength

issue: optical beat noise interference with data spectra at OLT Rx

P

t

P

t

P

t

t

ff1 f2 f3

Rxfreq.demux

electr.Rx

electr.Rx

electr.Rx

data 1

data 2

data 3

0

0

0

data 1

data 2

data 3

f1

f2

f3

SCMA upstream:

amjk 12

COBRACOBRASubcarrier multiplexing downstreamSubcarrier multiplexing downstream

fibrelaser

x

LO 1(VCO)

f

f x

LO i

x

LO j

x

LO N

f

f

photodiode

x

LO

amplifier

amplifier+ filter

fselected channel

amplifiier+ filter

transmitter

receiver

analogue

digital

. . .. . .

multiple services on separate electrical carriersa.o. for CATV broadcasting (as overlay in PON, or in Hybrid Fibre Coax networks)issues:- laser clipping, due to over-modulation

clipping noise- intermodulation products, due to non-linearities

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COBRACOBRAMultiple Access Multiple Access –– Optical Code DivisionOptical Code Division

t

codec1 c2 c3

RX

RX

RX

data 1

data 2

data 3

0

0

0

data 1

data 2

data 3

opt.corr.

opt.corr.

opt.corr.

t

t

ttime-sliced code, or wavelength-slicedfully independent data channels, asynchronous, no multiplexing gainlimited no. of codes limited no. of users 2-dim. -t codeissue: with t-code, high line rate (bit rate # chips/bit)issue: with -code, larger spectral width larger fibre dispersionissue: x-talk due to imperfect code orthogonality

OCDMA upstream:

amjk 14

COBRACOBRAMultiple Access Multiple Access –– Wavelength DivisionWavelength Division

fully independent data channels: functionally equivalent to P2Ppower budget improved w.r.t. -independent power splitno multiplexing gainspecific wavelength per node need for ‘colourless’ ONUissue: broadcast overlay, requires bypassing WDM muxhybrid WDM-TDM PON: enables more users on the PON, + multiplexing gain

t

1 2 3RxWDMdemux

data 1

data 2

data 3

2

1

3

data 1

data 2

data 3

Rx

Rx

WDMmux

WDMA upstream:

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amjk 15


BB access trends



WDM-PON


Radio over fibre


Concluding remarks

amjk 16

COBRACOBRA

APON/BPON ( ITUAPON/BPON ( ITU--T G.983.1, 1998 )T G.983.1, 1998 )General characteristicsGeneral characteristics

AN

155/622 Mbit/s155 Mbit/s

CCNB

BB

LT

LT

...

1:32 (64)

ONU

ONU

ONU

10-20 km

[P. Vetter, 2001; H. Ueda et al., IEEE Comm. Mag. 2001]

by FSAN (established in 1996)ATM cells (53 bytes, + 3 bytes BPON overhead for a.o. grants and BM)

down = 1480 .. 1580 nmup = 1260 .. 1360 nm (cheap FP lasers at ONUs)

differential fibre distance: 0-20 kmoptical path loss: class A 5-20 dB, class B 10-25 dB, class C 15-30 dB

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COBRACOBRATiming rangingTiming ranging

time

distanceranging grant

responseswithout

equalisation longestdistance

responseswith

equalisation

equalisationdelay

inserted

OLTONU2

ONU3

ONU1

measure distance (OLT sends ranging grant, upon receipt an ONU responds by sending ranging cell, OLT calculates distance from roundtrip delay)insert equalisation delay

puts ONUs virtually at equal distance from OLT, which facilitates synchronisation

[P. Vetter, 2001]

amjk 18

COBRACOBRAAmplitude rangingAmplitude ranging

[P. Vetter, 2001]

1 2 3

Power at NT

1 2 3

Power at LT

Decision levelset per timeslot

OLT

ONU2ONU3

ONU1

burst-mode receiver at OLT, fast decision level settingadapt also transmit power of ONU *

* Power Leveling Mechanism; in GPON G.984.2 in 3 steps of -3 dB

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COBRACOBRABroadband overlay (ITUBroadband overlay (ITU--T G.983.3, 2001)T G.983.3, 2001)

restrict APON downstream spectral windowfor additional digital services, or video distributionhigh WDM isolation required if electrical spectra of APON and overlay services overlap

amjk 20

COBRACOBRABPON protection (ITUBPON protection (ITU--T G.983.5, 2002)T G.983.5, 2002)

Type B: feeder fibre protection

TC protocol executes re-ranging after failure detection and optical switchingopto-mechanical switch (expensive)limited protection

LTOLT

ONU 1LT

ONU NLT

.

.

sparefibre

opticalswitch

[F. Effenberger et al., IEEE Comm. Mag., Dec. 2001][ITU-T Rec. G.983.5]

ONU 1LTLT

ONU NLTLT

LTOLT

LT

.

.

Type C: full system duplication

all equipment normally working fast restoration

also branch lines and ONUs protectedmay include unprotected ONUs

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COBRACOBRAEthernet PON (EPON)Ethernet PON (EPON)

standards set in IEEE 802.3ah Ethernet First Mile Task Force, in 2001Point-to-Multipoint (P2MP) optical Ethernetfull duplex, no CSMA/CDphysical layer largely similar to BPONvariable packet length, up to 1518 bytesGigabit Ethernet rate (1.25 Gbit/s) and frame format,incl. 25% line coding overhead (8B10B)Ethernet offers- high bandwidth, - low cost, - IP efficiency,- full services,- simplicitybut (in contrast to ATM)- no built-in QoS QoS has to be handled at IP level- issues with real-time services such as voice (due to latency and jitter)

[G. Pesavento, http://www.iec.org/online/tutorials/epon ]

amjk 22

COBRACOBRAGPON (ITUGPON (ITU--T G.984.1, 2003)T G.984.1, 2003)

[J.D. Angelopoulos et al., IEEE Comm. Mag. Feb. 2004]

by FSANmax. logical range 60 kmmax. physical reach 10 to 20 kmmax. differential range 20 km

down =1480 .. 1500nm, up =1260 .. 1360nmmax. split 128max. mean signal transfer delay 1.5 mscommercial solutions available

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amjk 23

COBRACOBRAGPON TC framing (ITUGPON TC framing (ITU--T G.984.3, 2004)T G.984.3, 2004)

OAMcontrol

OAMcontrol

OAMcontrol

Downstream

UpstreamBurst ONU 2 Burst ONU 3Burst ONU 1

ATM cell

Ethernet frame with GEM headerGPON OAM control

Burst OH

125 s125 s

ATM (optional)

ATM(optional)

Ethernet (over GEM)

Ethernet (over GEM)

Ethernet (over GEM)

Ethernet (over GEM)

ATM (optional)

Ethernet (over GEM)

• FEC in downstream & upstream (RS(255,239) block code, high code rate of 93.7%, can correct bursts of 50 bits)

Supportsnative ATM (like G.983)native packet (i.e. not over AAL5/ATM), and native TDM, by GPON Encapsulation Method

[T. Van Canegem, E. Gilon, et al., ISSLS 2004]

amjk 24

COBRACOBRAGPON TC efficiencyGPON TC efficiency

Assumption: 32 ONUs, every ONU is served every 0.75 ms

high efficiency: 95% of bandwidth can be used for IP data transport in E-GPON (Ethernet mode GPON)comparison with Gigabit Ethernet:

0

200

400

600

800

1000

1200

1400

Gig. Eth. E-GPON

Mbi

t/s

scheduling OH :frame delineationscheduling OH : PHYburst OHscheduling OH :control messagespayload encapulationOHline coding

payload

[T. Van Canegem, E. Gilon, et al., ISSLS 2004]

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amjk 25


BB access trends



WDM-PON


Radio over fibre


Concluding remarks

amjk 26

COBRACOBRAFixed wavelengthFixed wavelength--routed PONrouted PON

Passive Photonic Loop [Bellcore, 1989]needed in ONU for upstream :

-specific laser ( expensive stock maintenance),or colourless solutions:

reflective modulator ( source-free ONU; requires reflections-lean link), spectrally sliced broadband source (e.g. LED, or ASE from EDFA; limited power budget), orinjection-locked FP-LD or RSOA

AWG = Arrayed Waveguide Grating

ONU

ONU

ONU

ONU

ONUONUONUOLT

mux

/dem

ux

1 .. N

1

2

N-1

N

.

.

AW

G-ro

uter

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amjk 27

COBRACOBRASliced SLED + Reflective SOASliced SLED + Reflective SOA

For downstream: one DWDM laser per user in L-bandFor upstream: SLED with –10 dBm/0.1 nm in C-band40 users, each 0.4 nm bandwidth, 1.25 Gbit/s per user upstream, over 20 km SMFAWG in AN with 100 GHz channel spacingAPD receiverissue: reflections in fibre link

[F. Payoux et al., ECOC05]

Tx_1

R-SOA

Rx3dB

10km

10km

AWGRx_1

Rx_N

SLED

OLT

Tx 1

RSOA

Rx

ONU

AN

3dB

Mux

SLED

C/L band filter

Tx N

Rx 1

Rx N

amjk 28

COBRACOBRALink loss budget Link loss budget usingusing CWCW--fedfed RSOARSOA

Tx

Rx

RSOA

Pt,CW

Pr(t) G

data up x(t)AL

AR

CWtLRr PtxGAAtP ,2 )()(

RL

RL

r

r

AGAAGA

PP

/1/1' 2

2

1,

0,

[dB]'1'1log10 10

rP

received signal power

extinction ratio of received signal

power penalty

0

2

4

6

8

10

12

14

16

18

0 5 10 15 20 25 30 35

link loss [dB]

pow

er p

enal

ty [d

B]

AR=30 dBAR=20 dB

for G=27 dB , =0.1

G unmodulated RSOA gainx(t) gain modulation factor, x(t) 1AL link lossAR reflection loss in link

link loss budget decreases when link reflections increase

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COBRACOBRASelfSelf--injectedinjected RSOARSOA

SMF20km

SMF1km

AWG

OLT ONU 16ANWDM

1

FBG U16

FBG U1

16

.

.

.

AWG1

FBG D16

FBG D1

16

.

.

.

RSOARx

dataRSOA

Rx RSOARx 1.25

Gbit/sdata

RSOA lasing, locked to Bragg wavelength of FBG (over 24 nm in C-band), SMSR>25dB1x16 AWG-s, 200GHz channel spacingFBG on same silica material as the AWG no temperature-induced mismatch1.25 Gbit/s transmissionAPD receivers at OLTissue: spurious reflections in AN-ONU link

[S.-Y. Jung et al., OECC08, WeA.4]

ONU 1

amjk 30

COBRACOBRAIntegrated reflective transceiverIntegrated reflective transceiver

MZ duplexer

10 Gbit/s flip chip Si SOA driver

10 Gbit/s burst mode Si receiver

1, 2

2

QD-SOA-modulator

QD-SOA-detector

2

1

colourless ONU, using a reflective SOAoptical functions in quantum-dot InP IC, electronics in silicon 10 Gbit/swith bulk devices, >1.25 Gbit/s achieved

1, 22

1

HR

1

SOA modulator:• Modulating rate up to 1Gbit/s• Fibre-fibre gain up to 9 dB at 90 mA

injection current

Photodetector:• Responsivity up to 0.4 A/W at -2V• Bandwidth up to 25 GHz

data up

data down

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BB access trends



WDM-PON


Radio over fibre


Concluding remarks

amjk 32

COBRACOBRAMultiple access on the PONMultiple access on the PON

t

Rxtimedemux

TDM-PONflexible sharing of LT capacity

efficientlimited number of time slots per user

congestion at high loads

t

1 2 3RxWDMdemux

data 1

data 2

data 3

2

1

3

data 1

data 2

data 3

RxRx

WDMmux

WDM-PONeach user own -channel

no congestionvirtual P2Pno sharing of capacity

inefficient

Combine into hybrid WDM-TDM PON

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amjk 33

COBRACOBRA

Bypass/removal of Local Exchange Bypass/removal of Local Exchange by longby long--reach PONreach PON

major saving by reduction in (SDH) backhaul costsat 2.5 or 10 Gbit/s, symmetricalup to 110 km, with FEC and EDC 500 to 1000 customer sites per amplified PONWDM on feeder, “ to street corner” [D. Payne et al., ISSLS 2004]

[D. Nesset et al., ECOC 2005]

amjk 34

COBRACOBRA

Dynamic wavelength routing Dynamic wavelength routing in access networksin access networks

fibre

localexchange

access network cells

reconfigurable WDM-TDM PON: TDMA within a -channel of a routed WDM-PONmobility and fluctuating traffic load of users

provides capacity-on-demand to cellsoptimises utilisation of network resources

hot spot

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amjk 35

COBRACOBRAWavelengthWavelength--agile FTTHagile FTTH

{ down, i

,up,

j CW

}

{ up,j}

node 1

node 3

node 4

node 2

-mux

-dem

ux

1 G

bEda

ta in

1 G

bEda

ta o

uts

switch

headend station

Multi-casting -router

…161

control T/RT/R

Multi

-cas

ting

-rout

er

16

1

BM R

x

BM T

xre

fl. m

od.

ONU

…

contr

olT/

RT/

R

Multi-casting -router

… 16

1

control T/R

T/RMulti-casting -router…

16

1

control T/R

T/R

control

c= 1.3 m

WDM

CWDM

…

Tx 1

Tx 2

Tx 8

Tx 9 CW

Tx 10 CW

Tx 16 CW

…

Rx 9

Rx 10

Rx 16

…

flexibly allocating one or more -s per home, using ROADMsincl. protectioncolourless ONUs (using RSOA)

amjk 36

COBRACOBRA

1 2 3 N

Bmax

B

cell 1

cell 2

etc.

cell x

0

Wavelength reWavelength re--allocation of a cellallocation of a cell

transfer a cell to another -channel, as soon as it asks for more capacity than available in its present -channelconsiderably reduces the system blocking probability

…

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COBRACOBRAImpact of reconfigurationImpact of reconfiguration

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0 0.2 0.4 0.6 0.8 1

rel. system load

bloc

king

pro

b.

static125 Mbit/sflexible125 Mbit/sstatic63 Mbit/sflexible63 Mbit/s

Example:for 8 wavelength channels @ 1.25 Gbit/s (so 10 Gbit/s in total)256 users with Poisson-distributed calls, @ 63 Mbit/s or 125 Mbit/susing Chernoff’s upper bound approximation

by using reconfiguration, the system load can significantly be increased at the same blocking probability(e.g. doubled at Pblock=10-3 for 63 Mbit/s, and more for 125 Mbit/s)

amjk 38


BB access trends



WDM-PON


Radio over fibre


Concluding remarks

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amjk 39

COBRACOBRARadio over Radio over FibreFibre

Optical FibreUnlimited bandwidthLow lossLight weightEM immunity

To increase capacity:Smaller cells more antenna sitesHigher frequencies more complexity

increase capacity big cells have to shrink

Radio over Fibre

amjk 40

COBRACOBRARoFRoF techniquestechniques

RF Intensity modulation- double sideband carrier fading due to fibre dispersion- single sideband; by dual-electrode MZ modulator,

or by sharp optical filter - high requirements on Tx bandwidth and linearityOptical heterodyning- two narrow-linewidth sources e.g. by injection locking- self-heterodyning; e.g. with Optical Suppressed Carrier signal- only in SMF- dispersion-tolerantGenerating harmonics of a relatively-low frequency signal- a.o. by the Optical Frequency Multiplying technique- dispersion-tolerant- applicable in SMF and MMF…

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COBRACOBRAOptical Frequency MultiplyingOptical Frequency Multiplying

low-frequency CS technology (generating harmonics of the sweep freq. by FM-IM conversion in periodic filter)simple antenna stations (selecting the desired harmonic)very pure microwave high wireless capacity achievable by comprehensive modulation formats (such as x-QAM)dispersion-tolerant for SMF and MMF

[A.M.J. Koonen, Patent NL 1019047][A.M.J. Koonen and M. Garcia Larrode, JLT/MTT 2008]

fsw= 6.4 GHz

CWLD

-

- data

PD

fibrelink

0

fmm = 2N · fsw

Central Station Antenna Station

BPF

i(t)

periodicfilter

+ data

I

Q

120 Mbit/s64 QAM

@ 17.2 GHzafter 4.4 km

silica MMF

Freq. offset from 38.4 GHz carrier [Hz]

38.4GHz< 100Hz

RF p

ower

[dBm

] -30

-60

-90-500 0 +500

amjk 42

COBRACOBRAImpact of SMF chromatic dispersionImpact of SMF chromatic dispersion

0 20 40 60 80-80

-60

-40

-20

0

20

Fibre Length, [km]

Sig

nal S

treng

th, [

dB]

IM-DSBOFM

Measured delivered normalisedstrength of 22 GHz carrier at=1.55 m, usingIntensity-modulation, double sideband (IM-DSB); fading dips occur due to sidebands getting out of phase by fibre dispersionOptical Frequency Multiplying(OFM; 5th harmonic)

OFM is tolerant againstchromatic fibre dispersion, and hence suitable for link-switched routing.

[A. Ng'oma et al., Int. Microwave Symp. 2007][T. Koonen et al., OECC 2006]

(corrected for fibre losses)

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COBRACOBRADynamic capacity allocation in FWADynamic capacity allocation in FWA

MZI

LD1

sweepfreq. f1

data 1

MZImod.

LD2

sweepfreq. f2

data 2

MZImod.

LDN

sweepfreq. fN

data N

MZImod.

WD

M m

ux

-multicastingtun. OADM

fmm,x

BPFPD

-multicastingtun. OADM

x

fmm,y , fmm,z

BPFPD

y, z

BPFPDx

-mul

ticas

ting

tun.

OA

DM

fmm,y

y

Multi-standard operationRAP is -agnostic, may handle multiple RF signalsLink switching requires dispersion-robust RoF

[T. Koonen et al., ECOC 2004]

amjk 44


BB access trends



WDM-PON


Radio over fibre


Concluding remarks

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COBRACOBRAVersatile BB inVersatile BB in--home networkshome networks

Converged in-homebackbone network,integrating wired &wireless services

reduces installation and maintenance effortseases introduction and upgrading of servicesintegration e.g. by WDM

Coax Cable network

Twisted Pair network

RG

PCHDTVmobile

laptop

VoIP

faxprint PDA

mp3download

Satellite dish/FWA dish

opticalfibre

opticalfibre

webcam

Optical Fibrenetwork

converged in-home network on POF

coax

POF

SMF

amjk 46

COBRACOBRAPOF core dimensionsPOF core dimensions

1 mm core PMMA SI-POF

0.5 mm core PMMA GI-POF120 m core

PF GI-POF

50 m core multimodeGI fibre

9 m core silica single-mode fibre

chosen in POF-ALL project

PMMA POF:atten. <45 dB / 100 m for 450 nm< <650 nm(min. 8 dB / 100 m at =520 nm)

PF POF:atten. <8 dB / 100 m for 600 nm< <1350 nm

300 m Ø1mm core SI-POF:BW 10 MHz

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COBRACOBRAAttenuation of PMMA Attenuation of PMMA ØØ1 mm SI1 mm SI--POFPOF

spectral loss [dB/km]

400 450 500 550 600 650 700 750 800 850

wavelength [nm]

100

1000

200

2000

50

500

5000

120dB/km 85dB/km 145dB/km

460 nm 520nm 650nm

amjk 48

COBRACOBRAOvercomingOvercoming thethe limitedlimited BW of SIBW of SI--POFPOF

Baseband modulation formats4-PAM, 8-PAM and similar amplitude-modulation formatsrefs.: Gaudino et al., POF 2005, and Breyer et al., ECOC 2008

Quadrature-like modulation formatsQPSK, QAM-xbenefit from high market-volume QAM technologies for wireless LAN, DVB-C, and DOCSIS cable modemssolutions: direct-QAM, or WDM-QAM

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COBRACOBRADirectDirect--QAM 1 QAM 1 Gbit/sGbit/s overover ØØ1 mm SI1 mm SI--POFPOF

2 channel VSG, with 2 x 40 sub-carriers, 2 MHz spaced, carrying QAM-64 and -256 signals at 1.8 MBaud=650 nm edge emitting DVD laser diode

[ECOC’06, Th4.4.1, Sebastian Randel et al.]

BiasTee LD

VSG

D/A IMod

Q

50 MHz

AR

B

D/A

D/A IMod

QAR

B

D/A

150 MHz

~

~

+ PD VSA

DC

TIA

100m PMMA SI-POFØ 1 mm core

DVD LD =650nmlensed TO-can

silicon PDØ 1 mm area

Vector Signal Generator

Vector Signal Analyzer

0 50 100 150 200-40

-20

0

20

Frequency (MHz)P

ower

(dB

m)

Received Spectrum

amjk 50

COBRACOBRAWDMWDM--QAM systemQAM system

Vector Signal Generator

Vector Signal Analyzer

GreenLED

PIN PD

Blue LED

PIN PD

TIA

I

Q

QAMmodulator

QAMdemodulator

Greenblocking filter

dichroic 45º filter

dichroic 45º filter

WDM-MUXTx

WDM-MUXRxTIA

100mØ1mm corePMMA SI-POF

PINPD

PINPD

LED=460nm

LED=520nm

100Mbit/s QAM-16EVM<11.4%

[ECOC’08, We.2A.2, Jia Yang et al.]

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COBRACOBRARadioRadio--overover--Fibre in inFibre in in--house networkshouse networks

Application:- for pico-cells; range extension- inter-room wireless communication - multiple radio standards (WiFi, WiMAX, Zigbee, UWB, 60GHz, …)- wired-wireless services integration (vs. all-IP)- smart antennas, beam steering, MIMO, …- issue: overcoming MMF modal dispersion

Lack of standards …- many different techniques- issue: format-transparent signal transport

amjk 52

COBRACOBRA6464--QAM OFM over silica GIQAM OFM over silica GI--MMFMMF

fsw=2.867 GHz

PM IM SOA MZI

VSG

4.4 kmMMFBPF

17.2 GHzVSA

LNA PD

LD1.3 m

-wave carrier freq. 17.2 GHz64-QAM on subcarrier freq. 127 MHzsymbol rate 20 MBaud 120 Mbit/sover 4.4 km 50 m core silica GI-MMFalso over 25 km SMF @ 39.9 GHzalso multi-tone (up to 10 tones) 64-QAM operation shown at 18.3 GHz

EVM = 4.8% (< 5.6% req.)

I

Q

[A. Ng’oma et al., OFC2005]

VSG = Vector Signal GeneratorVSA = Vector Signal Analyzer

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COBRACOBRAInterInter--roomroom --wave wireless communicationwave wireless communication

transparent for any wireless signal formatany-to-any room communicationmulti-casting

HCC: Home Communication Controller

fibres(POF)

accessnetwork

[A.M.J. Koonen et al., OFC2008]

amjk 54

COBRACOBRAWavelengthWavelength--routedrouted RoMMFRoMMF networknetwork

[M. Garcia Larrode, A.M.J. Koonen, Trans. MTT 2008]

1300 1305 1310 1315 1320

−70

−60

−50

−40

wavelength, nm

Po, d

Bm

ADM−15drop port

1300 1305 1310 1315 1320

−70

−60

−50

−40

wavelength, nm

Po, d

Bm

ADM−15through port

RoMMF add/drop node(MMF FBG with BW=100 GHz)

drop and through portssilica Ø50 m core GI-MMFdownlink: 120 Mbit/s 64-QAM, at 23.7 GHzuplink: 64-QAM, at fIF=300 MHz, with IM/DD

1=1303.8 nm, 2=1310.1 nm, 3=1314.8 nm

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COBRACOBRA

Impact of Impact of RoFRoFon wireless access protocolson wireless access protocols

IEEE 802.16 (WiMAX)centrally scheduled MACfibre delay may exceed timing boundaries of the MAC protocols and round trip delaystime division duplex (TDD): gap between downlink (DL) burst and uplink (UL) burst, may be adapted to accommodate fibre delay

RGCS AS

RFoptical link

gapDL subframe UL subframe

frame j frame j+1 frame j+2frame j-2 frame j-1 ......Round trip delay

Extra guard time gap

Throughput reduction <1% if fibre link < 500 m

[M. Garcia Larrode, NOC2005][A.M.J. Koonen and M. Garcia Larrode, JLT/MTT 2008]

amjk 56

COBRACOBRAConcluding remarks (1/2)Concluding remarks (1/2)

Re Access networks:Optical fibre techniques are key for future-proof, versatile and high-capacity service provisioning in access networks.Fibre makes a powerful match with existing DSL, coax, and wireless customer access networks.For larger user areas and/or higher user numbers, a P2MP passive network can bemore cost-effective than a P2P one.TDM-PON provides efficient capacity sharing on a P2MP passive network.WDM-PON provides P2P functionality on a P2MP passive network

easy upgrading on a per-customer base.A hybrid WDM-TDM PON enables easy network scaling, and can provide capacity-on-demand efficiently by means of flexible wavelength routing

optimises the exploitation of the system’s resources. Radio-over-fibre techniques can deliver high-capacity microwave signals very efficiently, in particular when using optical routing.

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COBRACOBRAConcluding remarks (2/2)Concluding remarks (2/2)

Re In-building networks:After fibre has brought broadband capacity up to the home’s doorstep, in-home fibre networks are needed to deliver it to the user.

An optical fibre in-home backbone enables integration of wired and wireless services, eases maintenance and upgrades.

Large-core multimode Plastic Optical Fibre is attractive for DIY installation.

Wired services: Quadrature Amplitude Modulation allows Gbit/s speeds over large-core MMF.

Wireless services: Optical Frequency Multiplication allows high-capacity pico-cell communication over MMF.

Flexible optical routing yields- dynamic provisioning of capacity-on-demand, and - reconfigurable multi-standard pico-cell wireless inter-room communication.

amjk 58

COBRACOBRAAcknowledgementAcknowledgement

Funding from

the European Commission, in FP6 project POF-ALL – Paving the Optical Future with Affordable Lightning-fast Links ,FP7 project ALPHA – Architectures for fLexible Photonic Home and Access networks,FP6 Network of Excellence ISIS, andFP7 Network of Excellence BONE

the Dutch Ministry of Economic Affairs, in the IOP Generieke Communicatie project Future Home Networks

is gratefully acknowledged.

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Documents

Tu1A1 ECOC2008 0831 paper