nobel technical audit wp5 objectives & achievements march 08, 2006 work package 5 transmission...
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NOBEL Technical AuditWP5 Objectives &
AchievementsMarch 08, 2006
Work package 5
Transmission and Physical Aspects
Bernd Bollenz, Herbert Haunstein
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WP5 - Outline
1) Organisation- Objectives (year 2)- Partners
2) Achievements- Penalty budget based light path design- Static Network Optimization- Transparency regions- Started extension to dynamic traffic demand
3) Conclusion & Outlook for Phase 2- Rules for physical layer optimization- Continue work in new WP5 (merged WP5/6/7)- Main focus – experimental verification of concepts
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WP5 – Objectives (year 1 year 2)1. Identify the main building blocks for transmission in next generation flexible
broadband optical networks as described in WP1 (including intelligent optically transparent crossconnects, configurable OADMs etc)
2. Build models and simulate network elements with regard to physical constraints in transparent optical networks
3. Develop algorithms to allow route selection and resource optimisation in intelligent optically transparent (analogue) networks and perform computer simulations to assess their performance. This will include an assessment of the value of wavelength conversion
4. Derive conclusions on the physical feasibility of transparent optical networks as an input for WP1 / WP4
5. Define major design optimisation criteria and identify design rules for transparent transmission in dynamic optical networks and provide input to the international standardization bodies (e.g. ITU-T SG15)
6. Derive most suitable transport formats (bit rate, modulation, bursts) with respect to cost, distance and robustness against performance impacting functionality in transparent optical networks and for the different network segments (core, metro)
7. Evaluate and model the impact of all building blocks like optical amplifiers (EDFA, Raman), optical wavelength converters, optical regenerators, adaptive TX/RX interfaces (e.g. for GVD/PMD mitigation) and advanced coding algorithms for further improvement of network efficiency (cost and/or performance) to ensure network wide operation
8. Model the dynamic behaviour of transparent optical networks, for circuit and burst switched applications, especially with regard to transmission on optical amplified fibre links
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WP5 - PartnersACREO (ACREO)
Alcatel CIT (ACIT)
Alcatel SEL (ASEL)
British Telecom (BT)
France Telecom (FT)
Lucent Technologies (LUGmbH)
Ericsson GmbH (MCONDATA)
Pirelli Labs (PLABS)
Siemens (SIEMENS)
Telecom Italia (TILAB)
TeliaSonera (TS)
T-Systems Nova (T-Systems)
University of Athens (NTUA)
Person months distribution 2005
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RegenerationRequired ?
TransportInterface Rx
Transport Interface Tx
ObjectiveDefine design rules for
1) Network configuration (equipment placement) for a given topology and static traffic demand under cost constraints (e.g. for reference networks) 2) Operation Dynamic traffic demand: Routing & wavelength assignment under physical constraints
Optical transparent transport network
ObjectiveOptimisation of physical layer design
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Extend to dynamic traffic
ActivitiesOptimisation of physical layer design
Building blocksModulation format, FEC, Amplifiers
Tunable lasers, OADM, OXC
Network Design Rules
Light Path Design Rules
Transmission effects, …
“O-E-O vs. Transparency”
Cost model on wavelength
level
Optical monitoring functions
Requires additional equipment
Network Dimensioning
Reference Networks – Traffic demand
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Time line & sub teams of WP5
BuildingBlocksReferenceNetworks
Dedicated sub teams:- Carrier‘s group (reference networks, traffic demand estimation)- Optical monitoring group (jointly WP1/4)- Optical transparency cost analysis group (jointly WP2/6/7)- Path computation algorithms group - PMD modelling and mitigation concepts group
M12
Physical FeasibilityLight Path Design
Network Design Rules Optimization
M4 M15 M21 M24
Dynamic Network simulation(Routing)
Specificationof networkelements forverification
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Achievements
Continued activities- PMD mitigation concepts
Verification of building blocks- Inline OSNR measurement- Distributed PMD compensation
Cost comparison of physical layer alternatives- Relative cost of subsystems
Network design- Transparent regions- Optimized equipment placement- Dynamic traffic demands (started)
OSNR
Cost
PMDCconcepts
NetworkOptimization
Engines
Dist.PMDC
Networkdesign
Transparentregions
Slide 11
Slide 12/13
Slide 14
Slide 15
Slide 16
Slide 17-19
Slide 20
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Summary & outlook
Summary (year 2)
1) Deliverables (D19, D26 & D28)
2) Penalty budget based light path design
3) Network design
Equipment placement
Cost optimization for physical layer
4) Optimized Network design (transparent regions)
Outlook Nobel phase 2
Apply Design Rules in experiments for verification
Extend network design to dynamic traffic demand
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Technical details
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Concepts:
optical PMDC– 1stage
– 2stage
– in-line(distributed)
electronic equaliser
– FFE+DFE
– MLSE (=VE)
Building blocks PMD mitigation - overview eopmdc_axes
PMD / Tbit 0.0 0.1 0.2 0.3 0.4 0.5
rel.
OSNR p
enal
ty (d
B)
-2
0
2
4
6
8
multi-stage
Rx2stage
OPMDC1stage
Q-p
enalty [d
B]
PMF1PC1
feedback signal2 PMFs
(c)(c)11x44PMF2
PC2
PMF:variable DGDPC
feedback signal
(b)(b)11x33
SC with variable DGD: VarDGD
.....
Cn-1
Tc
Cn
C0
Tc
C1
CUref
TB
-+
B1
FFE
DFE
-1
0
1
2
3
4
5
6
0 20 40 60 80 100
DGD [ps]
Q-f
ac
tor
pe
na
lty
[d
B]
@ 1
*10
-3
DB(ATC,model 1) NRZ (ATC,model 1) DB(VE,model 1)
NRZ (VE,model 1) NRZ(FFE+DFE,model 2) NRZ(VE,model 2)
CSRZ (ATC,model 1) CSRZ (VE,model 1)
duobinaryNRZ
VE1
FFE+DFE
CSRZ
ATCVE
ATC
VE
Q-penalty vs. DGD (=3xPMD)
VE2
-1
0
1
2
3
4
5
6
0 20 40 60 80 100
DGD [ps]
Q-f
ac
tor
pe
na
lty
[d
B]
@ 1
*10
-3
DB(ATC,model 1) NRZ (ATC,model 1) DB(VE,model 1)
NRZ (VE,model 1) NRZ(FFE+DFE,model 2) NRZ(VE,model 2)
CSRZ (ATC,model 1) CSRZ (VE,model 1)
duobinaryNRZ
VE1
FFE+DFE
CSRZ
ATCVE
ATC
VE
Q-penalty vs. DGD (=3xPMD)
VE2
Performance metrics:
Q-thresholds vs. DGDfrom literature
Q-penalty vs. DGD for different modulation formats
Q-penalty vs. PMD incl. equalisation by FFE+DFE
0
1
2
3
4
5
6
7
8
12 17 22Baseline Q (dB)
Resid
ual Q
pen
alt
y a
fter
PM
D
eq
ualizati
on
(d
B)
5ps
10ps
15ps
20ps
25ps
Clock
Viterbi Equalizer
Analog low pass filter AGC Enhanced
FECADC
CDR
Automaticgain control
Analog to digitalconverter BER =1·10-3
Recovered data
Clock recovery back
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OPM Technology Example: OSNR Measurement by Polarisation Nulling (I)
Technique allows “in-band” measurement of OSNR (no noise floor on either side of signal required)
Commercially available
Good performance, but potential issues with depolarised signal (PMD) and polarised ASE (PDL)
Performance comparison OSA - Argos instrument(cw channel)
8
12
16
20
24
28
32
8 12 16 20 24 28 32OSNR / dB (reference)
OS
NR
(d
B)
/ m
easu
red
OSA
ARGOS - 20GHz BW
ARGOS - 50GHz BW
TXAtten-uator
OSA
Opt.Filter EDFA
True-OSNRTester
PolCon / Scrambler
PMD-Emulator
Back-back path
PMD-free path
PDL
Experimental Setup:
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OPM Technology Example: OSNR Measurement by Polarisation Nulling (II) Measurement with partially polarised ASE noise (emulation of
PDL)
Polarisation nulling device does not see ASE co-polarised with signal measurement inaccuracy depends on PDL in system
OSNR with polarised ASE (90degr. to signal)
10
12
14
16
18
20
22
10 12 14 16 18 20 22
OSNR (reference) / dB
OS
NR
(m
easu
red
) /
dB
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
PD
L e
qu
ivale
nt/
dB
OSA
ARGOS (20GHz)
PDL / dB
OSNR with polarised ASE (0degr. to signal)
16
16.5
17
17.5
18
18.5
19
19.5
20
16.0 17.0 18.0 19.0 20.0
OSNR (reference) / dBO
SN
R (
mea
sure
d)
/ d
B
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
PD
L e
qu
ival
ent/
dB
OSA
ARGOS (20GHz)
PDL / dB
back
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PMD-C Measurement results
Polarization Scrambler
Tx10G DGD OSNR
Rx10G
BER
Polarization Scrambler
Pol. Contr. OA
Polarization Controller
PMD Emulator (1st order)
OPMOpt. Power
meter
Polarizer
Measurement setup:
Measurement results:OSNR penalty vs. DGD @ BER 1e-6
(10.7 Gb/s NRZ)
0
1
2
3
4
5
6
7
8
9
10
0 10 20 30 40 50 60 70 80
DGD (ps)
OS
NR
pe
na
lty
[d
B]
uncompensated
compensated
• Compensation possible with the polarizer approach at 10 Gbit
• Can compensate 4.7 ps mean PMD (2 dB OSNR penalty)
Conclusion:
System parameters:
• Modulation format NRZ• Bitrate 10.7 Gbit• BER w/o FEC 1e-6
back
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Based on relative cost (750km transponder card = 1) Opaque vs. transparent/hybrid nodes with broadcast and
select architecture for the optical plane (details in D26) Study partly includes grooming Transparency limits of 750, 1500 and 3000km Example for cost formulae
transponder/ col. line card
EXC
EXC
OXC/OADM/OPP
opaque
transparent/hybrid
Cost comparison studyPhysical layer only
Broadcast & Select Architecture with Wavelength Blocker & passive splitter/combiner
Note: restricted flexibility in coloured ports for local add/drop; however lower day-one cost
n = number of connected fibre
pairs
40 channels max:
Fixed cost(WB40chFix)
e.g. OSC, power supply, etc. 2.0
Variable cost(WB40chVar1)
Including power control unit & passive splitter / combiner; no amplifiers
3.45 * n
(WB40chVar2) Mainly wavelength blocker, 100 GHz grid 2.9 * n * (n-1) / 280 channels max:
Fixed cost(WB80chFix)
e.g. OSC, power supply, etc. 2.2
Variable cost(WB80chVar1)
Including power control unit & passive splitter / combiner; no amplifiers
5.95 * n
(WB80chVar2) Mainly wavelength blocker, 50 GHz grid 3.2 * n * (n-1) / 2
back
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Flexible node
Transparent node
Lower tech(say, MTD 750 km)
Higher tech(say, MTD 1500 km,MTD 3000 km)
Flexible node
Transparent node
Lower tech(say, MTD 750 km)
Higher tech(say, MTD 1500 km,MTD 3000 km)
EXC
OXC/OADM/OPP
Transparent regionsGeneralised transparent domains
back
Generalised transparent islands
Transparent/translucent core
Generalised transparent islands
Transparent/translucent core
flexible partition of a hybrid optical network into a set of smaller Generalised Transparent Domains (GTDs) and a transparent/translucent core
each GTD (and the core) will be engineered separately on the basis of its own inner core size (partitioning avoids any network over-engineering applying different levels of technology)
flexible hybrid nodes at the boundary of each GTD ensure flexibility of the whole network
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3 reference networksTraffic matrices
Ultra Long Haul
RMI
BAR
TARNAP
NOLRMS
BOP
PISFIR ANC
PGA
PES
BLZ
VENVRS
TRI
PDS
GENSAV
TOR
ALE
PCA
BREMIMMIB
COM
LAM
CAT
PAR
CTZ
BGM
CA
SS
RMI
BAR
TARNAP
NOLRMS
BOP
PISFIR ANC
PGA
PES
BLZ
VENVRS
TRI
PDS
GENSAV
TOR
ALE
PCA
BREMIMMIB
COM
LAM
CAT
PAR
CTZ
BGM
CA
SS
Metro
Long-Haul
Traffic Matrix
7
2 3 4 5 6
1
8 9 11
12 13 14 15 16
17 18 19 21 22 23
24 25 26 27 28
29 30 31 33 34
35 36 37 38
20
32
107
2 3 4 5 6
1
8 9 11
12 13 14 15 16
17 18 19 21 22 23
24 25 26 27 28
29 30 31 33 34
35 36 37 38
20
32
10
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Simulated annealing based planningTechnology selection
Year 2005 2006 2007
Total network cost 1254 1648 2104
Total network cost, mixed transponders 1089 1426 1762
Number of lightpaths 226 315 478
Number of lightpaths > 750 km 20 38 50
Longest path 986 km 1097 km 1124 km
Heuristic RWA approach fast computation even for large networks
Fixed-alternate routing (selection of alternative routes from a fixed set)
– Reduces computational time by limiting search space
– Makes it possible to simulate the critical paths in advance
Wavelength allocation by first fit
Results for the full topology:
Low percentage of paths > 750 km significant cost reduction by mix of transponder reach
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Simulated annealing based planningTopology optimization
Cost optimisation of network topology (by removing links):
2005 2006 2007
Scenario 2005(optimum)
2005(10% free)
2006(opt)
2006(10%)
2007(opt)
2007(10%)
Total network cost 1150 1168 1454 1465 2001 2039Mixed transponders 991 1002 1266 1264 1660 1706
Only small cost penalty for keeping 10% of wavelength resources free
back
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Multi-purpose simulation engines
General approach Heuristic Exact Shortest Path (SP), heuristic Shortest Widest Path (SWP)
Heuristic (Layered Approach)
Integer linearprogramming (ILP)
Heuristic & incremental ILP for network planning phase
Routing and Wavelength Assignment
Separate steps: network resources allocated before LPs are set up
SP: Routing and WA simultaneously
SWP: First routing and then WA based on criteria
Layered approach with multiple prioritized criteria
Part of ILP with bit-rate dependent length-restriction; unprotected, 1+1 protected
Pre-routing as Hamiltonian cycle; RFWA for an incremental connection request
Routing Fixed-alternate (for unprotected traffic)
Adaptive Adaptive Any path within length-restriction
Adaptive, optimized by ILP approach
Wavelength Assignment
First-Fit with Simulated Annealing & Genetic Algorithm
First Fit / Best-Fit / Random-Fit & customizable cost
First-Fit Implicit in ILP Adaptive, optimized by ILP approach
Sorting of requests Sorted acc. to # of hops (descending)
Balanced & adaptive Balanced & adaptive
Optimization Goal Weighted minimum of:# of wavelengths,
# of hops, path length
SP-Routing: Minimum spans, WA based on spans or Q
SWP-Routing: Max # of available continuous wavelengths, cost or Q-based WA
Minimum used fibres Minimum cost Minimum fibre length (prioritized), lower wavelength numbers preferred
Protection “1+1”, protected path: fixed routing
None “1+1”, protected path: shortest cycle
1+1 “1+1”
Environmental Conditions
Static Dynamic Static & Dynamic Static Static
Computational effort
Medium High Medium High
Medium
Physical layer impairments
Maximum length < 1200 km, intrinsic
Q-factor, FWM, XPM PMD, Q-factor based on noise
Mapped into length restriction
intrinsic
Preferentially Considered Network
17-nodes German 16-nodes Pan-European 17-nodes German 17-nodes German 17-nodes German
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