NOBEL Technical Audit WP5 Objectives & Achievements March 08, 2006 Work package 5 Transmission and Physical Aspects Bernd Bollenz, Herbert Haunstein

NOBEL Technical AuditWP5 Objectives &

AchievementsMarch 08, 2006

Work package 5

Transmission and Physical Aspects

Bernd Bollenz, Herbert Haunstein

2© Lucent Technologies 2006 – Project Restricted

H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

Technical details


H. Haunstein

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


H. Haunstein

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:


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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


H. Haunstein

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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Documents

NOBEL Technical Audit WP5 Objectives & Achievements March 08, 2006 Work package 5 Transmission and Physical Aspects Bernd Bollenz, Herbert Haunstein