10GBASE-T Tutorial Overview - IEEE 802 Interim January 2003 10GBASE-T 1 10GBASE-T Tutorial Overview....

IEEE802.3 Interim January 200310GBASE-T

1

10GBASE10GBASE--T Tutorial OverviewT Tutorial Overview

William JonesSolarflare Communications

[email protected]_1_9_2003_overview.pdf


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Introduction: Realizing 10GBASEIntroduction: Realizing 10GBASE--TT

• Application Overview• Cabling & Impairments• Strawman System• Implementation• Performance Results• Conclusion


3

Applications OverviewApplications Overview

• 10-Gb/s Ethernet connections <= 100m• Utilize installed base of structured Cat 5e UTP• Upgrade from 1000BASE-T

10GBase-TTransceiver

11/4/2002

MAC 10GBase-TTransceiver MAC

Cat5e UTP(4 pairs)

up to 90m

Wallplateor

Patch Panel

Wallplateor

Patch Panel

up to 5m up to 5m


4

Channel ImpairmentsChannel Impairments

R

THYBRID

R

T HYBRID

R

THYBRID

R

T HYBRID

R

THYBRID

R

T HYBRID

R

THYBRID

R

T HYBRID

NEXT14

NEXT12

NEXT13

FEXT14

FEXT13

FEXT12

Far Echo

Near Echo

Alien Crosstalk, EMI


5

Characterization vs. SpecificationCharacterization vs. Specification

• Cat 5/5e cable must be high quality with minor structural variations to meet TIA-568 requirements

• 100 MHz (or 250 MHz) “limit” imposed by TIA qualification requirements– not the physical limitations of the cable

• Cable properties stable beyond 500 MHz– depends mainly on transmission line geometry and

construction materials

• Minor structural variations and connector discontinuities affect channel transmission, but not catastrophically


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Cat 5e Channel: Insertion LossCat 5e Channel: Insertion LossMeasured Cat 5e 100 Meter Channel Insertion Gain at 20 C

0 50 100 150 200 250 300 350 400 450 500-60

-50

-40

-30

-20

-10

0

Frequency (MHz)

Inse

rtion

gai

n (d

B)

Manufacturer AManufacturer BManufacturer CCat 5e limitExtended limit


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Cat 5e Channel: NEXTCat 5e Channel: NEXT

0 100 200 300 400 500 600-80

-70

-60

-50

-40

-30

-20

-10

0

Measured Pair-to-pair NEXT Coupling into Cat 5e Pair 1

Frequency (MHz)

Inse

rtion

gai

n (d

B)

NEXT12NEXT13NEXT14

Cat 5e limitExtended limit


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Cat 5e Channel: FEXTCat 5e Channel: FEXT

0 50 100 150 200 250 300 350 400 450 500-100

-90

-80

-70

-60

-50

-40

Measured Pair-to-pair FEXT Coupling into Cat 5e Pair 1

Frequency (MHz)

Inse

rtion

gai

n (d

B)

FEXT12FEXT13FEXT14


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Alien NEXTAlien NEXT

0 50 100 150 200 250 300 350 400 450 500-80

-70

-60

-50

-40

-30

-20

Frequency (MHz)

Inse

rtion

gai

n (d

B)

Adjacent connectorNon-adjacent connectorCat 5e NEXT limitExtended limit

Single (4-pair cable) disturber, 40 meter length unbundled

Cat 5e Power Sum Alien NEXT vs. Patch Panel Position


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EMI EMI -- EmittedEmitted• >100 MHz on Cat 5e can meet FCC Class A

~12 dBm launch power limitation• < 500 MHz limits larger high frequency emissions

0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 02 0

2 5

3 0

3 5

4 0

4 5

5 0

5 5

6 0

W o rs t-C a s e R a d ia te d E m is s io n s a t 3 M e te r s - C a t 5 e U T P

F re q u e n c y (M H z )

Elec

tric

field

(dB

uV/m

)

- 8 0 d B m /H z s ig n a lF C C C la s s A l im i tF C C C la s s B l im it


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Baseline RequirementsBaseline Requirements• ~ 10 dBm Transmit power• ~ 400 MHz Bandwidth• ~ 40 dB Echo & NEXT Cancellation, ~ 20 dB FEXT Cancellation• Alien NEXT suppression for crowded installations

Received Signal & Residual Noise Terms

-160.00

-150.00

-140.00

-130.00

-120.00

-110.00

-100.00

-90.00

-80.00

0 50 100 150 200 250 300 350 400

Frequency (MHz)

PSD

ref

to

Inpu

t (d

Bm

/Hz)

-20.0

-10.0

0.0

10.0

20.0

30.0

40.0

50.0

60.0

SNR

(dB

)

Rcv Sig

Res Echo

Res NEXT

Res FEXT

Res ANEXT

Bkgnd

SNR


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StrawmanStrawman System: PAMSystem: PAM--10 Coding10 Coding

• Given the characteristics of the channel/disturbers, capacity is maximized with an analog bandwidth around 400MHz

• 10Gbps is achieved with a baud rate of 833MHz and 12 bits/baud or 3 bits/pair (4 pairs)– Minimum requirement of PAM8 for uncoded operation

• PAM9 may be sufficient for Ethernet control symbols• PAM10 needed for both control and Trellis coding• Extension of 1000BASE-T

– 4D, 8-state Trellis code (one dimension per pair)– 6 dB coding gain relative to uncoded 10PAM


13

Comparison With 1000BASEComparison With 1000BASE--TT

High-Performance FEXT cancellation

No specified FEXT cancellation

High-Performance NEXT cancellation

Moderate NEXT cancellation

833 Mbaud, ~400 MHz used bandwidth

125 Mbaud, ~80 MHz used bandwidth

Full duplex echo-cancelled transmission

Full duplex echo-cancelled transmission

10-level with Trellis code across pairs

5-level with Trellis code across pairs

Multilevel coded PAM signaling (3-bits/symbol)

Multilevel coded PAM signaling (2-bits/symbol)

Straw Man 10GBASE-T1000BASE-T


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PCS SER & BER Straw Man GoalPCS SER & BER Straw Man Goal

19 20 21 22 23 24 25 26 2710

-14

10-12

10-10

10-8

10-6

10-4

10-2

100

Coded PAM10 simulation SERCoded PAM10 Theory SERCoded PAM10 Theory BER

1000BASE-TReqm’t

25.3 dB

• For an aggregate slicer SNR of 25.3 dB with five dominating noise terms requires individually around 32 dB SNR

Slicer Input SNR (dB)


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Implementation Requirement Implementation Requirement -- ISIISI• Pre- & Post-Cursor Interference from limited

Bandwidth• Post-Cursor Dominates (>100 terms)• Feedforward & Decision

Feedback EqualizationSolution

FeedForwardEqualizer

DecisionFeedbackEqualizer

Slicer

_+


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Implementation Requirement Implementation Requirement -- EchoEcho

• Full duplex needed for limited BW• Compromise hybrid for Tx/Rx isolation• Impedance mismatches

require residual echocancellation

• > 40 dB rejection


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Implementation Requirement Implementation Requirement -- NEXTNEXT

• High-level interference from transmitters• Very long response time• > 40dB NEXT cancellation

wireline

Tx Channel 0

Rx Channel 1(target rcvr)

NextCoupling

wireline

Rx Channel 0(victim rcvr)

Tx Channel 1(interfering xmtr)


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Implementation Requirement Implementation Requirement -- FEXTFEXT

• Pre- and post-cursor elements of interference• Based on an equal-level FEXT (ELFEXT) model• Uncompensated in 1000BASE-T• Must be cancelled in 10GBASE-T• > 20 dB cancellation

wireline

Tx Channel 0

Tx Channel 1(interfering xmtr)

FextCoupling

wireline

Rx Channel 0(victim rcvr)

Rx Channel 1(target rcvr)

chanelffext HHH ⋅=


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Challenging ImplementationChallenging Implementation

• A new approach to problem solving needed to meet SNR requirement (> 25.3 dB)

• Efficient reuse of resources in MIMO modeling

• Utilization of parallel structures


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Traditional Signal ProcessingTraditional Signal Processing• Echo & NEXT cancellation

SISOSISOSISOSISO

SISOSISOSISOSISOSISOSISOSISOSISO

SISOSISOSISOSISO

T4T3T2T1

++++ ++++ ++++ ++++ R4

• 16 Single Input Single Output (SISO) processing elements(scalar filters)

• With canceller taps on the order of several hundred10 Tera Operations (TOps)!


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Modern Signal ProcessingModern Signal Processing

• Echo & NEXT Cancellation

R4

T4T3T2

MIMO

T1

• One Multiple Input Multiple Output (MIMO) processingelement (matrix filter)

• Exploits correlation to reduce interference common to all received channels

• Enables massive reuse of computing resources


22

Modern Signal ProcessingModern Signal Processing

• Data recovery & Fext cancellation

d1

d2

d3

d4

T1

T2

T3

T4

R1

R2

R3

R4

H1

F21

F31

F41

MIMOCHANNEL

MUD

d1

d2

d3

d4

• Multiuser Detector (MUD) of MIMO channel providessimultaneous data decisions & interference removal


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Parallelizing FIRsParallelizing FIRs• One high rate N tap filter

( ) )()( 21

120 zHzzHzH −+=

x(n)H(z)

y(n)

H0(z)

H1(z)

H1(z)

H0(z)

Z-1

x(n)

Z-1

+

+ +

Z-1

y(n)

2

2

2

2

• Good for clock limited or high speed applications• Four half rate N/2 tap filters• Equivalent number of operations per unit time


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Efficient Efficient Parallelization Parallelization

H0(z)

H0(z)+H1(z)

H0(z)

Z-1

x(n)

Z-1

+

+ +

Z-1

y(n)

2

2

2

2+ +_

_

• Four filters reduced to three

• 25% improvement in efficiency

•Greater efficiency with greater parallelism


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Digital Circuit Straw Man GoalsDigital Circuit Straw Man Goals

• Puts total DSP requirements at 1.5 Tera Operations (TOps)

• Quad 1000BASE-T requires 1.0 TOps 150% increase in possible aggregation with 50%

increase in complexity today!

• CMOS technology


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Analog Circuit Straw Man GoalsAnalog Circuit Straw Man Goals

• Transmitter: DAC & Line driver– >40 dB Linearity– 450 MHz Bandwidth

• Receiver: Hybrid, LNA & ADC– >8 bits ENOB– 833 MSPS

• Clock – 833 MHz

• CMOS technology


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ISI Performance ISI Performance -- After EqualizationAfter Equalization

0 0.5 1 1.5 2 2.5 3 3.5 4x 108

-70

-60

-50

-40

-30

-20

-10

0

10

Frequency

Spec

trum

(dB)

Equalized Signal

Residual ISI

• FFE scales to produce unit variance hard decisions

Tx MAG MAG Rx ENFX EQCat 5e cable


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ISI Performance ISI Performance -- Symbol StreamSymbol Stream

a)

b)

0 1 2 3 4 5 6 7 8 9 10

x 104

-2

-1

0

1

2a) Rx Far End Signal b) Slicer Input Vs. time

0 1 2 3 4 5 6 7 8 9 10

x 104

-2

-1

0

1

2

MAG MAG Rx ENFX EQCat 5e cable

a b

Tx


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Echo Performance Echo Performance -- SNR @ DetectorSNR @ Detector

0 0.5 1 1.5 2 2.5 3 3.5 4x 108

-70

-60

-50

-40

-30

-20

-10

0

10

Frequency

Spec

trum

(dB)

Equalized Signal

Residual Echo




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NEXT Performance NEXT Performance -- SNR @ DetectorSNR @ Detector

Tx MAG MAG Rx ENFX EQ

0 0.5 1 1.5 2 2.5 3 3.5 4x 10

8

-70

-60

-50

-40

-30

-20

-10

0

10

Frequency

Spec

trum

(dB)

Equalized Signal

Residual Next(3)

Cat 5e cable



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FEXT Performance FEXT Performance -- SNR @ DetectorSNR @ Detector




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Total Total Slicer Slicer SNRSNR

Tx MAG MAG Rx ENX EQCat 5e cable

0 0.5 1 1.5 2 2.5 3 3.5 4x 10

8

-60

-50

-40

-30

-20

-10

0

10

Frequency

Spec

trum

(dB)

Equalized Signal

Total Noise

Total Noise Power Goal (-25.3) • FFE scales to produce unit variance hard decisions


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Sequenced StartupSequenced StartupN E, P F DONE

DONEFE, TNSLAVE

MASTER

N = ECHO/NEXT Canceller Convergence T = Tim ing AcquisitionP = Phase Adjustment

F = FEXT Canceller ConvergenceE = Equalizer Convergence


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Summary: Realizing 10GBASESummary: Realizing 10GBASE--TT

• Careful attention to media characterization beyond 100MHz

• Evolution of 1000BASE-T

• Modern signal processing methods

• Feasible CMOS realizations of digital & analog circuits

• Q&A

10GBASE-T Tutorial Overview - IEEE 802 Interim January 2003 10GBASE-T 1 10GBASE-T Tutorial Overview....

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Transcript of 10GBASE-T Tutorial Overview - IEEE 802 Interim January 2003 10GBASE-T 1 10GBASE-T Tutorial Overview....