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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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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amjk 3
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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COBRACOBRAOutlineOutline
BB access penetration
PON multiple access techniques(TDMA, SCMA, OCDMA, WDMA)
TDM-PON solutions (BPON, EPON, GPON)
WDM-PON
Dynamically reconfigurable optical access
Radio over fibre
Concluding remarks
amjk 10
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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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
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]
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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]
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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
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
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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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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amjk 31
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
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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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
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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Vol. 6 - 81
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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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amjk 41
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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amjk 43
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
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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amjk 45
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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amjk 47
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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amjk 49
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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amjk 51
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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amjk 53
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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amjk 57
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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