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Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3 302090064 FS0261 [email protected]

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Page 1: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Network Access Transmission Model for Evaluating xDSL Modem Performance

Jack Douglass, Paradyne InternationalChair TIA TR30.3

Sept 5, 2002, FS-VDSL

TR30.3 302090064FS0261

[email protected]

Page 2: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Presentation Overview

• Purpose of Presentation to FS-VDSL • Access Network Models Projects for Evaluating

xDSL Modem Performance• Value of xDSL Network Model• Network Model Overview• Access Network Simulator• Advantages of NMC Methodology • Obstacles to Creating a European Network

Model that implements NMC methodology • Proposal for Creating European Network Model • Discussion

Page 3: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Purpose of Presentation

• Establish a formal liaison between FS-VDSL and TR30.3 • Request that FS-VDSL open a project to assist in the

develop of a European xDSL Network Model that uses Network Model Coverage (NMC) methodology– TIA/EIA-876, North American Network Model, has been released

for publication– ETSI has opened a project in the form of a Permanent Document

(ETSI TM6 PD (02) 07) to create an European Network Model– Initial model would be for frequency range of 0 to 1.104 MHz– Principles can be applied to VDSL

Page 4: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Purpose of Presentation (continued)

• Work with FS-VDSL to acquire European Network Statistics (e.g., loop, crosstalk, ingress, etc.) that are needed to build the Network Model(s)– In the past FS-VDSL has be able to reduce obstacles such as: lack of

publicly available information regarding loop and crosstalk statistics, unbundling competition issues, regulation issues

• Provide a template that can be used to develop European Network Model(s)

• Determine the best way to forward FS-VDSL/TR30.3 work to ETSI TM6 – Contribution to ETSI TM6 concerning Network statistics for development

of Network Model(s) in TM6 — may be anonymous – Contribution to ETSI TM6 that has completed Model(s) for inclusion into

appropriate ETSI document (e.g., Technical Report) — may be anonymous

Page 5: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Access Network Model Projects for Evaluating xDSL Modem Performance

Page 6: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

TIA/EIA-876 — North American Network Model Uses Network Model Coverage (NMC) methodology and

principles to evaluate and compare the performance of xDSL modems

Statistically based portrait of the access network and impairments Loop Model based on a combination of loop surveys, including an

anonymous 14 million line survey Central Office wiring models Central Office impairments (e.g., CEXT, Composite CEXT) Intermediate xDSL interferers Customer Premises drop and wiring models Customer Premises impairments (e.g., RFI, POTS signalling,

splitters/filters, AC induced interference) Definitive set of loop and noise conditions for consistent and

repeatable test results

Page 7: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

TIA/EIA-876 — North American Network Model Models DSL access network over the frequency range of 0 to

1.104 MHz Technology independent Can be applied to both splittered and non-splittered xDSL systems Principle of TIA/EIA-876 readily apply to higher frequencies such as

used by VDSL Crosstalk, Ingress, Loop Models may require some modification Test equipment must be able to support the desired operating range

Model to be used by Network Service Providers, PTTs, test houses, magazines, product reviewers, users and designers

TIA/EIA-876 is intend to compliment the existing xDSL testing standards It is a performance test not interoperability or conformance test

Page 8: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

TIA/EIA 876 Network Model

xDSL Network Block Diagram with Impairment Injection Points

Page 9: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

ETSI TM6— European Network Model

• Project opened in the form of a Permanent Document to create a European xDSL Network transmission Model based on the NMC principles and methodology

Page 10: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Value of xDSL Network Model

Page 11: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Value to Operating Companies and Service Providers

• Predict candidate product performance on their networks as Percentage of the network where satisfactory operation will be obtained

• Determine the potential market coverage as a function of different parameters/factors such as: Quality of Service, line rate, data throughput, connect time, stability, technology, modulation technique and modem enhancements

• Select optimum technology for a proposed service based its Network Model Coverage Performance

• Develop Business Cases and establish Tariff objectives • Minimize costs associated with loop qualification, loop

modifications and truck rolls

Page 12: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Value to Manufactures and Design Engineers

• Helps find design weaknesses

• Facilitates isolating and resolving field problems

• Assists in evaluating different technologies

• Predicts real access network performance

Page 13: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Comparison Testing

• Model can be used by test houses, magazines and product reviewers to compare the performance of different brands of xDSL modems or systems– Test results are intended to reflect the customer

experience

Page 14: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Network Model Overview

Page 15: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Example General European Access Network Model

MDFStreet

Cabinet

TelephoneExchange

LocalDistribution

PointDSLAM

ExchangeNoise

Injection

IntermediateNoise

Injection

CPENoise

Injection

Distribution Cable25(?)-pair binder0.4, 0.5, 0.63 mm

2 to 7 km

Branch Cable25-pair binder

0.5 mm PE0.25, 0.5, 0.63, 1.0 km

Drop Wire0.5 mm PE

50 m

Exchange0.5 mm150 m

• Cable lengths and types are intended as a basis for discussion. • Intermediate noise injection (Remote DSLAM) point may not be

necessary.

Page 16: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Cumulative Distribution for Crosstalk Models

• Cumulative Distribution Values– Basis for the crosstalk mix used in Crosstalk Impairment

Combination Tables• Residential/Multiunit Model

– asymmetrical weighting• Business Model

– symmetrical weighting • Projected for the year 200x

– Current xDSL deployment statistics – Projected xDSL deployment

• Assumes 25 (?) -pair binders with yy% vacant pairs – Churn/disconnect — cross-connected at street cabinet to reserve

loop assignment for the next tenant – Defective pairs – Reserved for future growth

Page 17: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Residential/Multiunit Cumulative Distribution (CD) Number of Disturbers of Each Type

CD Associated

Severity

ISDN BA

2B1Q

ISDN BA

4B3T

2 Mbit/s HDB3

(2-pair)

HDSL 2B1Q

392 ks/s (3-pair)

HDSL 2B1Q

584 ks/s (2-pair)

HDSL 2B1Q 1160

ks/s (1 pair)

HDSL CAP 2320 kbit/s

( 1 pair)

ADSL over

POTS FDD

ADSL over

POTS EC

ADSL over ISDN FDD

ADSL over ISDN EC

ADSL lite

SDSL 784

kbit/s

SDSL 1505 kbit/s

SDSL 2056 kbit/s

50% D

70% C

85% B

95% A

Page 18: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Business Cumulative Distribution (CD) Number of Disturbers of Each Type

CD Associated

Severity

ISDN BA

2B1Q

ISDN BA

4B3T

2 Mbit/s HDB3

(2-pair)

HDSL 2B1Q

392 ks/s (3-pair)

HDSL 2B1Q

584 ks/s (2-pair)

HDSL 2B1Q 1160

ks/s (1 pair)

HDSL CAP 2320 kbit/s

( 1 pair)

ADSL over

POTS FDD

ADSL over

POTS EC

ADSL over ISDN FDD

ADSL over ISDN EC

ADSL lite

SDSL 784

kbit/s

SDSL 1505 kbit/s

SDSL 2056 kbit/s

50% D

70% C

85% B

95% A

Page 19: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Crosstalk Impairment Combinations

• Crosstalk Impairment Combinations (IC) are specified for each Loop– Residential/Multiunit model– Business model – A, B, C and D Crosstalk severity levels

• A — Most severe • D — Least severe

– LOOs — A = 5%, B =15%, C = 30% and D = 50% (Total = 100%)• FEXT may be handled differently in mathematical analysis and hardware

simulation– Hardware simulator

• NEXT is inserted at both ends so that tests can be run in both directions simultaneously• Insertion of NEXT at one end of the loop produces an approximation of FEXT at the

other end– Mathematical analysis

• FEXT should be included at both ends

• Assumes Worst-case crosstalk coupling• Disturber Model may vary between Exchange and CPE end• CPE Crosstalk is xx% co-located and yy% distributed

– Distributed crosstalk may be do to operating range of some system is less than the loop can accommodate

– Crosstalk may be distributed as a result of distributing services to other customer along the way.

Page 20: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Crosstalk Impairment Combinations (IC) Loop XX (LOO/Length) – Residential/Multiunit

Impairment Severity A B C D Impairment LOO 5% 15% 30% 50%

NEXT Number of Interferers Exchange Injection Point Exchange Wiring (150 m) Self-NEXT MDF ISDN BA 2B1Q ISDN BA 4B3T 2 Mbit/s HDB3 (2-pair) HDSL 2B1Q 392 ks/s (3-pair) HDSL 2B1Q 584 ks/s (2-pair) HDSL 2B1Q 1160 ks/s (1-pair) HDSL CAP 2320 kbit/s (1-pair) ADSL over POTS FDD ADSL over POTS EC ADSL over ISDN FDD ADSL over ISDN EC ADSL lite SDSL 784 kbit/s SDSL 1505 kbit/s SDSL 2056 kbit/s

CPE Injection Point ISDN BA 2B1Q ISDN BA 4B3T 2 Mbit/s HDB3 (2-pair) HDSL 2B1Q 392 ks/s (3-pair) HDSL 2B1Q 584 ks/s (2-pair) HDSL 2B1Q 1160 ks/s (1-pair) HDSL CAP 2320 kbit/s (1-pair) ADSL over POTS FDD ADSL over POTS EC ADSL over ISDN FDD ADSL over ISDN EC ADSL lite SDSL 784 kbit/s SDSL 1505 kbit/s SDSL 2056 kbit/s

Page 21: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Crosstalk Impairment Combinations (IC) Loop XX (LOO/Length) – Business

Impairment Severity A B C D Impairment LOO 5% 15% 30% 50%

NEXT Number of Interferers Exchange Injection Point Exchange Wiring (150 m) Self-NEXT MDF ISDN BA 2B1Q ISDN BA 4B3T 2 Mbit/s HDB3 (2-pair) HDSL 2B1Q 392 ks/s (3-pair) HDSL 2B1Q 584 ks/s (2-pair) HDSL 2B1Q 1160 ks/s (1-pair) HDSL CAP 2320 kbit/s (1-pair) ADSL over POTS FDD ADSL over POTS EC ADSL over ISDN FDD ADSL over ISDN EC ADSL lite SDSL 784 kbit/s SDSL 1505 kbit/s SDSL 2056 kbit/s

CPE Injection Point ISDN BA 2B1Q ISDN BA 4B3T 2 Mbit/s HDB3 (2-pair) HDSL 2B1Q 392 ks/s (3-pair) HDSL 2B1Q 584 ks/s (2-pair) HDSL 2B1Q 1160 ks/s (1-pair) HDSL CAP 2320 kbit/s (1-pair) ADSL over POTS FDD ADSL over POTS EC ADSL over ISDN FDD ADSL over ISDN EC ADSL lite SDSL 784 kbit/s SDSL 1505 kbit/s SDSL 2056 kbit/s

Page 22: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Specified Steady-State Impairments

Impairment Severity Notes 0 1 2 3

Exchange Injection Point

Splitter amplitude distortion Splitter delay distortion Background noise Balance AC power interference

CPE Injection Point

Splitter amplitude distortion Splitter delay distortion Background noise Balance AM radio interference AC power interference

• Specified Steady-State Impairment Combinations Severity levels 0 - 3– Primarily ingress noise – Severity 0 is a baseline null case– Severities 1 through 3 have increasing levels of ingress noise– Do not have an associated LOO

Page 23: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

AM Radio Interference

Signal Type Centre Frequency (kHz)

Common mode level

Differential mode level

• Severity level 1, 2, and 3

Page 24: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Specified Transient Impairments

Impairment Severity Notes 0 I II III

POTS ringing signal POTS call progress tones POTS hook transients POTS ring trip Impulse noise Microinterruptions Voiceband coupling to DSL band

• Not part of the NMC calculation– Important part of the Access Network

Transmission Model – Must be accounted for in testing

Page 25: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Example General Loop Diagram

MDF Wiring0.5 mm100 m

Distribution Cablexx-pair binder

0.4, 0.5, 0.6 mm2 to 7 km

Branch Cable25-pair binder

0.5 mm PE0.25, 0.5, 1.0 km

Drop Wire0.5 mm PE

50 m

DSLAM CPE

Page 26: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Example Test Loop Make-up and LOOs

*Loop Loss values @ 100 kHz and @ 300 kHz are approximate and assume same cable type is used for entire length

Loop Loop No.

Exchange Wiring

(0.5 mm)

Distribution Cable Branch Cable Drop Wire LOO

Length (m)

Length (0.4 mm)

Length (0.5 mm)

Length (0.63 mm)

Length (0.5 mm)

Length (0.63 mm)

Total Loop

Length (km)

DC Resista

nce (ohms)

Loop Loss @ 100 kHz

(dB)

Loop Loss @ 300 kHz

(dB) Gauge (mm)

PE

Length (m) PE

%

1 150 1.75 0.25 2.00 560 21.06 27.60 0.5 50 2 150 1.75 0.50 2.25 630 22.90 30.27 0.5 50 3 150 2.25 0.25 2.50 700 26.56 34.72 0.5 50 4 150 2.65 0.10 2.75 770 29.85 38.81 0.5 50 5 150 2.50 0.50 3.00 840 31.14 40.95 0.5 50 6 150 2.25 1.00 3.25 910 32.07 42.74 0.5 50 7 150 3.25 0.25 3.50 980 37.54 48.96 0.5 50 8 150 3.25 0.50 3.75 1050 39.38 51.63 0.5 50 9 150 3.00 1.00 4.00 1120 40.31 53.42 0.5 50

10 150 4.00 0.25 4.25 1190 45.78 59.64 0.5 50 11 150 3.75 0.25 0.50 4.50 1095 46.71 61.43 0.5 50 12 150 3.75 0.00 1.00 4.75 1050 48.55 64.10 0.5 50 13 150 3.00 1.75 0.25 5.00 1153 47.65 64.11 0.5 50 14 150 3.25 1.50 0.50 5.25 1179 50.40 67.67 0.5 50 15 150 3.50 1.00 1.00 5.50 1159 53.14 71.23 0.5 50 16 150 2.25 3.25 0.25 5.75 1212 50.43 69.46 0.5 50 17 150 1.75 3.75 0.50 6.00 1161 50.44 70.35 0.5 50 18 150 2.00 3.25 1.00 6.25 1142 53.19 73.91 0.5 50 19 150 1.00 4.25 1.00 0.25 6.50 1154 49.16 70.83 0.5 50 20 150 1.50 3.75 1.00 0.50 6.75 1204 52.82 75.28 0.5 50 21 150 2.00 3.00 1.00 1.00 7.00 1210 56.48 79.73 0.5 50

Page 27: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Premises Wiring Models

• Based on G.996.1, section 6.2.2• Single Family and Small Office Premises Models

– Daisy Chain Wiring– Star Wiring– Star Wiring with Central ADSL Splitter and Direct Line

• Multi-Unit/Business Wiring– Multi-Tenant Residence / Business -- Daisy Chain Wiring– Multi-Tenant Residence / Business -- Star Wiring– Small Office Wiring– Large Office Wiring

Page 28: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Example Customer Premises Models Based on G.996.1, section 6.2.2

Daisy Chain Wiring Model

Page 29: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Network Model Coverage Tables

• Tables for Network Model Coverages (NMC) of 100%, 95%, 90% and 65% are typically provided– Used for both Residential/Multiunit and Business

Models• Test Channel Score

– intersection of the IC and test loop – Score is Product of Loop LOO and IC LOO

• < 100% NMC Tables – Remove Loop/IC combinations with lower percentage

Scores – Run on Test Channels that have Scores– Reduces the test time with slightly reduced resolution

Page 30: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Network Model Coverage Tables

Network Model Coverage = 100%

Loop No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

IC Severity

LOO

D 50% C 30% B 15% A 5%

Network Model Coverage = 95%

Loop No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

IC Severity

LOO

D 50% C 30% B 15% A 5%

Network Model Coverage = 90%

Loop No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

IC Severity

LOO

D 50% C 30% B 15% A 5%

Network Model Coverage = 65%

Loop No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

IC Severity

LOO

D 50% C 30% B 15% A 5%

Page 31: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Example Network Model Coverage Tables

• Examples NMC=100% and NMC=90% Tables are provided to illustrate how to construct and use NMC Tables

• Arbitrary values have been assigned to the loop LOO, so that the example test channel scores can be calculated

• A Test Channel Score is calculated by taking the product of the loop LOO and the IC LOO

• All Test Channels are included in an 100% NMC Table• Lower percentage scores have been removed from 90%

NMC Table (actual total score is 90.05) • Actual NMC Table can be constructed once the Loop

LOOs have been assigned based on loop network statistics

Page 32: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Example Network Model Coverage = 100%

Loop No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

IC Severity

LOO 5% 8% 9% 10% 8% 7% 6% 6% 6% 5% 5% 4% 4% 3% 3% 3% 2% 2% 2% 1% 1%

D 50% 2.50% 4.00% 4.50% 5.00% 4.00% 3.50% 3.00% 3.00% 3.00% 2.50% 2.50% 2.00% 2.00% 1.50% 1.50% 1.50% 1.00% 1.00% 1.00% 0.50% 0.50% C 30% 1.50% 2.40% 2.70% 3.00% 2.40% 2.10% 1.80% 1.80% 1.80% 1.50% 1.50% 1.20% 1.20% 0.90% 0.90% 0.90% 0.60% 0.60% 0.60% 0.30% 0.30% B 15% 0.75% 1.20% 1.35% 1.50% 1.20% 1.05% 0.90% 0.90% 0.90% 0.75% 0.75% 0.60% 0.60% 0.45% 0.45% 0.45% 0.30% 0.30% 0.30% 0.15% 0.15% A 5% 0.25% 0.40% 0.45% 0.50% 0.40% 0.35% 0.30% 0.30% 0.30% 0.25% 0.25% 0.20% 0.20% 0.15% 0.15% 0.15% 0.10% 0.10% 0.10% 0.05% 0.05%

Page 33: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Example Network Model Coverage = 90%

Loop No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

IC Severity

LOO 5% 8% 9% 10% 8% 7% 6% 6% 6% 5% 5% 4% 4% 3% 3% 3% 2% 2% 2% 1% 1%

D 50% 2.50% 4.00% 4.50% 5.00% 4.00% 3.50% 3.00% 3.00% 3.00% 2.50% 2.50% 2.00% 2.00% 1.50% 1.50% 1.50% 1.00% 1.00% 1.00% 0.50% 0.50% C 30% 1.50% 2.40% 2.70% 3.00% 2.40% 2.10% 1.80% 1.80% 1.80% 1.50% 1.50% 1.20% 1.20% 0.90% 0.90% 0.90% 0.60% 0.60% B 15% 0.75% 1.20% 1.35% 1.50% 1.20% 1.05% 0.90% 0.90% 0.90% 0.75% 0.75% A 5%

Page 34: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Test Procedure and Network Model Coverage (NMC) Curves

• Run each test channel (that has an associated score), in the NMC Table along with Specified Steady-State Impairment Severity 0 (null case) and one of the Premises Wiring Models. Note: The number of tests can be reduced by using a lower percentage NMC Table.

• Measure desired parameter(s) (e.g., connect rate, throughput, connect time, etc.).

• Repeat each test channel with Specified Steady-State Impairment Severities 1 through 3. Tests may also be repeated with different Premises Wiring Models and/or Specified Transient Impairments.

• Sort measured parameter(s) along with associated NMC Scores in a descending order using a spreadsheet or similar mechanism.

• Plot the measured parameter(s) on the Y axis and the associated NMC Score on the X axis.

• The resulting curve shows the performance (in terms of the measured parameter) as a percentage of the Network Model.

Page 35: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Family of 65% NMC Curves for Steady-State Impairments Severity 0 to 3

Throughput vs Network Model Coverage Percentage for 62% Residential Model with Premises Wiring Model – P1

0

1000

2000

3000

4000

5000

6000

7000

8000

0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00%

% of Network

Co

nn

ect

Rat

e (k

/b/s

)

Severity 3

Severity 2

Severity 1

Severity 0

Page 36: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Access Network Simulator

Page 37: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Network Model Simulator Implementation • Network Model Simulators

– Mathematical Simulator– Hardware Simulator

• Ideal Network Model Simulator – Separate Loop sections – Separate Noise sources

• Practical and Cost-Effective Simulator– Single loop simulator

• Exchange wiring• Distributed Cable• Branch Cable• Drop wire

– Composite Exchange Interferers and the Composite CPE Interferers • FSAN mixed crosstalk combination method • Account for associated loop sections • Account for noise injection points. • Typically use Arbitrary Waveform Generator (AWG).

– Premises wiring simulator– Device(s) Under Test (DUT).

Page 38: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Ideal Network Model Simulator

*Exchange injection Point

DSLAMDUT

Exchangexx mmyy m

Drop WireZz mm

PEww m

MDF StreetCabinet

LocalDistribution Point

Network Interface

*MDF Injection Point

*Intermediate Injection Point

*CPE Injection Point

*Inject noise at designated point as specified in Tables 5, 6, 7 and 10

Page 39: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Practical and Cost-Effective Network Model Simulator

DSLAMDUT Loop Simulator Premises

Wiring

CPEDUT

*Crosstalk simulation is a composite of different interferers from different injection points and includes the effects of loops

PSDX Exchange (f)

Exchange Composite Interferer*AWG

PSDX CPE (f)

CPE Composite Interferer*AWG

Page 40: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Typical Test SetupxDSL Simulator and Modems

Telephone Network Simulator(Line Current/Dial Tone) – ADSL only

Loop Simulator

xDSLCPE Modems (ATU-R)

Premises Wiring

Simulator

AWGAWG

xDSL DSLAM s(ATU-C)

Page 41: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Screen of Arbitrary Waveform Generator (AWG) showing Crosstalk Impairment on CO Side

Uses Loop and Crosstalk transfer functions to accurately simulate impairment combinations

Page 42: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Screen of Arbitrary Waveform Generator(AWG) showing Crosstalk and RFI Impairment on CPE Side

Uses Loop and Crosstalk transfer functions to accurately simulate impairment combinations

Page 43: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Advantages of NMC Methodology

Page 44: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Advantages of NMC Methodology

• Predicts the performance of the system/modem over the real access network– Statistically accurate indication of overall performance based on

operation over good, medium and worst case loop and noise conditions

– Evaluates more than just stress conditions • Test results are displayed as a family of NMC Curves

– Performance differences between products or technologies can be easily seen

• NMC testing can be viewed as running many individual SNR points over a wide range of loop and noise conditions

• NMC methodology which was implemented in both TIA Standards and ITU Recommendations was a key factor in improving the quality and performance of voiceband modems, over the years– NMC principles can do the same for xDSL Technology

Page 45: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Advantages of NMC Methodology

• Operating Companies and Service Providers– Predict candidate product performance on their

networks as Percentage of the network where satisfactory operation will be obtained

– Determine the potential market coverage as a function of different parameters/factors such as: Quality of Service, line rate, data throughput, connect time, stability, technology, modulation technique and modem enhancements

– Select optimum technology for a proposed service based its Network Model Coverage Performance

– Develop Business Cases and establish Tariff objectives – Minimize costs associated with loop qualification, loop

modifications and truck rolls

Page 46: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Advantages of NMC Methodology

• Manufacturers and Design Engineers– Predict real access network performance– Find design weaknesses– Isolate/resolve field problems– Evaluate different technologies

Page 47: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Advantages of NMC Methodology

• Model to be used by test houses, magazines and product reviewers to compare the performance of different brands of xDSL modems or systems– Test results are intended to reflect the customer

experience

Page 48: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Proposalfor Creating European xDSL Network Model

Page 49: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Proposal• Establish a formal liaison between TR30.3 and FS-VDSL

to develop a European xDSL Network Model that uses Network Model Coverage (NMC) methodology

• FS-VDSL Committee opens a Network Model Project – Study NMC Methodology– Acquire European Network Statistics (e.g., loop, crosstalk, ingress,

etc.) that are needed to build the model(s)– Assist in developing a European xDSL Network Transmission

Model(s) based on NMC principles and sample templates• Initial model would not include VDSL

• Jointly determine the best method to forward FS-VDSL / TR30.3 work to ETSI TM6 – Contribution to ETSI TM6 concerning Network statistics, so a

Network Model(s) can be developed in ETSI — may be submitted anonymously

– Contribution to ETSI TM6 that have Model(s) for inclusion into appropriate ETSI document (e.g., Technical Report) — may be submitted anonymously

Page 50: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Key Committees and Role

• FS-VDSL– Vehicle for acquiring network statistics and creating network

model– Ad hoc meetings to analyze network statistics and draft document

• TIA TR30.3– Experience in creating network model– Liaison/Work with FS-VDSL and ETSI TM6 to create network

model– Work on drafting the model during TR30.3 meetings– Possible vehicle to anonymously submit final network model

• ETSI TM6– European Access Network Model

Page 51: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Obstacles

• Country to country variations of loop/crosstalk/noise statistics and characteristics

• Lack of publicly available information regarding loop/crosstalk statistics

• Unbundling Competition

• Regulations

Page 52: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Proposed Procedure

• Create straw-man Network Model(s) using sample template and experience

• Gather statistical information on European Access Network– Loop (configuration, binder size, type of cable, gauge, etc.)– Crosstalk data (numbers and types of interferers currently installed and

marketing deployment information)– Steady-State Impairments (e.g., Ingress impairments, AM Radio, etc.)– Transient Impairments

• Revise straw-man Network Model(s) based on statistical information• Validate model using real xDSL equipment of different technologies• Compare validation results with known real world performance• Submit Model(s) and/or network statistics to ETSI TM6 for possible

inclusion into an appropriate ETSI document (e.g., Technical Report)– may be submitted anonymously

Page 53: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Key FS-VDSL Contributors

• Operating Companies

• Chip manufacturers

• 8 Companies supported opening the project at the ETSI TM6 meeting

Page 54: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Time Table

• Time table is mainly dependent on how quickly statistical information can be obtained

• Model can be created fairly quickly using sample template

• Time to create model can be reduced by having ad hoc meetings and working on the document at the FS-VDSL and TR30.3 committee meetings.

Page 55: Network Access Transmission Model for Evaluating xDSL Modem Performance Jack Douglass, Paradyne International Chair TIA TR30.3 Sept 5, 2002, FS-VDSL TR30.3

Discussion

• Determine how work can be applied to a VDSL version of the model

• Comments, Suggestions and Recommendations