Part IV – Wireline Multiuser Examples

1 Multiuser WondersMultiuser Wonders

Part IV – Wireline Multiuser ExamplesPart IV – Wireline Multiuser Examples

March 31, 2001April 26 2001

September 9, 2001September 9, 2001

Prof. John M. CioffiProf. John M. Cioffi

Dept of EEDept of EE

Stanford UniversityStanford University

[email protected]@stanford.edu


Parts 3 and 4: Outline/ScheduleParts 3 and 4: Outline/Schedule

2:00-2:452:00-2:45 MU TheoryMU Theory 2:45-3:302:45-3:30 channels for wirelinechannels for wireline 3:30-4:00 3:30-4:00 CoffeeCoffee 4:00-4:304:00-4:30 DSL and Ethernet archDSL and Ethernet arch 4:30-5:154:30-5:15 Multiuser improvementsMultiuser improvements


Outline – Part 4Outline – Part 4

DSL and Ethernet ApplicationsDSL and Ethernet Applications Evolution of DSL and DSM vs SMEvolution of DSL and DSM vs SM

UnbundlingUnbundling Towards ethernetTowards ethernet

Multiuser Spectrum BalancingMultiuser Spectrum Balancing Vectored VDSLVectored VDSL Vectored EthernetVectored Ethernet


DSL in 2001DSL in 2001

Data, some voice beginning, to 1.5/.5 MbpsData, some voice beginning, to 1.5/.5 Mbps Conservative deployments (9 Million lines)Conservative deployments (9 Million lines)

Telephone company officeTelephone company office

ServiceProvider

split

POTSNetworkdigitaldigital

analoganalog

analoganalog

Splitter ?

0-4 miles0-4 miles

customer premisescustomer premises

GGAATTEEWWAAYYSS DSLAM

Voice

Muxor

Demux

ADSLmodem

ADSLmodem

.

.

ADSLmodem

InternetServiceProvider

digitaldigital

ADSL


DSL Future ApplicationsDSL Future Applications

Multiline voice (VoDSL)Multiline voice (VoDSL) Video (internet, packet based)Video (internet, packet based)

Not likely “traditional” TVNot likely “traditional” TV Small Businesses – less asymmetricSmall Businesses – less asymmetric

filt

Enet.

802.11

VoDSLinterface

Home/business wiring

A/VDSLA/VDSL

Enet

100BT100BTGigabit EGigabit E

wireless (802.11) orwireless (802.11) orother distribution possibleother distribution possiblewithin CPEwithin CPE

ToToserviceservice

providerprovider routerrouter


Part Fiber, Part DSL = VDSLPart Fiber, Part DSL = VDSL

Only 12,000 of 10Only 12,000 of 1077 businesses connected by fiber all the way – essentially 0 residences businesses connected by fiber all the way – essentially 0 residences Rather ONU’s/remote terminals, incrementally with timeRather ONU’s/remote terminals, incrementally with time

How long is fiber? Twisted-Pair?How long is fiber? Twisted-Pair? Incremental trade-off with time/demandIncremental trade-off with time/demand

.1- 2 km

Split

VDSL

ONU

fiber

To 100 MbpsTo 100 Mbps

Split

POTSC-Bank

VDSL

LT


Ethernet – 10BTEthernet – 10BT

STAR wiring – collision detection not really usedSTAR wiring – collision detection not really used Hub is electronic version of a “coax-wired” connectionHub is electronic version of a “coax-wired” connection All lines on Hub share the 10 MbpsAll lines on Hub share the 10 Mbps

100’s millions deployed on copper100’s millions deployed on copper Manchester codingManchester coding Category 5 tp (20 dB less xtalk than phone lines- cat 3, 24 gauge)Category 5 tp (20 dB less xtalk than phone lines- cat 3, 24 gauge) Each line is 2 pairs (so 2 of 4 in cat 5)Each line is 2 pairs (so 2 of 4 in cat 5)

100 meters (systems run longer)100 meters (systems run longer) Result of delay specification related to days in which HUB was a coax.Result of delay specification related to days in which HUB was a coax.

HubHub(yellow(yellowcoax)coax)

InternetInternetRouterRouter

ServerServer


Introduction of BridgesIntroduction of Bridges

Little higher level than Hub, which is an electronic Little higher level than Hub, which is an electronic version of a “yellow coax”version of a “yellow coax”

Allows each line’s 10 Mbps to be differentAllows each line’s 10 Mbps to be different Dedicated connection to each userDedicated connection to each user

HubHub

InternetInternetRouterRouter

bridgebridgeServerServer

HubHub



Each user gets 100 Mbps, dedicated linkEach user gets 100 Mbps, dedicated link MLT3 code (4B5B to ternary) – 125 MHzMLT3 code (4B5B to ternary) – 125 MHz 100 meter range – back compatible with 10BT100 meter range – back compatible with 10BT

Data sent when packets availableData sent when packets available Delay spec really not needed on link anymoreDelay spec really not needed on link anymore Remains a 2-wire duplex situationRemains a 2-wire duplex situation Lead suppliers do 170m rangeLead suppliers do 170m range

BridgeBridge(router)(router)

ServerServer

InternetInternet



Continuous, 250 Mbps on each of 4 lines for 1 Gbps totalContinuous, 250 Mbps on each of 4 lines for 1 Gbps total Continuous onlyContinuous only All 4 wires in cat 5 used by a single user in duplex, echo-cancelled fashionAll 4 wires in cat 5 used by a single user in duplex, echo-cancelled fashion 125 MHz 5-level (effective 4, or 2 bits) PAM on each line125 MHz 5-level (effective 4, or 2 bits) PAM on each line

100 meters – physical layer constraint (lead suppliers do 160 m)100 meters – physical layer constraint (lead suppliers do 160 m)

RouterRouterServerServer

InternetInternet

44


Ethernet Faster?Ethernet Faster?

10,000BT – vectored multiuser, 100 10,000BT – vectored multiuser, 100 metersmeters

RouterRouterServerServer

InternetInternet

44

VDMTVDMT

VDMTVDMT

VDMTVDMT VDMTVDMT

VDMTVDMTVDMTVDMT

VDMTVDMTVDMTVDMT

VDMTVDMT


Ethernet – longer (EFM)Ethernet – longer (EFM)

VDSL=VDMTVDSL=VDMT 100BT (4 wires) > 1 km100BT (4 wires) > 1 km Single wire – very high speeds, Single wire – very high speeds,

Distance/rate tradeoffDistance/rate tradeoff Vectored/spectrally balanced – number of pairs Vectored/spectrally balanced – number of pairs

allocated, etc. allocated, etc.

RouterRouterDSLAMDSLAM

ServerServer

InternetInternet

44

VDMTVDMT

VDMTVDMT

VDMTVDMT VDMTVDMT

VDMTVDMTVDMTVDMT

VDMTVDMTVDMTVDMT

VDMTVDMT

Sites may nowSites may nowbe at homes/businessesbe at homes/businessesat end of telco linesat end of telco lines







Unbundling in DSLUnbundling in DSL

Different service providers can “rent” lines to Different service providers can “rent” lines to customerscustomers Consequent emissions between lines (crosstalk)Consequent emissions between lines (crosstalk)

Gets worse with wider bandwidths (shorter lines)Gets worse with wider bandwidths (shorter lines) Can be reduced with asymmetric transmissionCan be reduced with asymmetric transmission

ILEC – often wants asymmetricILEC – often wants asymmetric CLEC – often wants symmetricCLEC – often wants symmetric

ILECILEC

CLECCLEC


Spectrum ManagementSpectrum Management

Regulate the spectra of the different service Regulate the spectra of the different service providers within the cableproviders within the cable Minimize radiation between cablesMinimize radiation between cables Balance interest of symmetric/asymmetric (CLEC/ILEC)Balance interest of symmetric/asymmetric (CLEC/ILEC)

Fixed spectra defined for each type of DSL Fixed spectra defined for each type of DSL service, no matter where it is used in the world service, no matter where it is used in the world STATICSTATIC spectrum management spectrum management

CO-based SM before FCC for approvalCO-based SM before FCC for approval ONU/fiber-feed case still under studyONU/fiber-feed case still under study


Network

fiberCentral

Office SP #1 LTSP #1..

twisted pair, DSL

Fiber, FTTH

SP #2 SP #2..

multiple fibersin this area lead

to multiple fibersto home

DSL Line-Unbundled Evolution?DSL Line-Unbundled Evolution?

Fiber for each service provider?Fiber for each service provider? Space at LT for each service provider?Space at LT for each service provider?


HFC – Hybrid Fiber CoaxHFC – Hybrid Fiber Coax

CableCableHead endHead end

satellitesatellite

splitsplitfiberfiber

Fiber from head end to first splitFiber from head end to first split More bandwidth, easier bidirectionallyMore bandwidth, easier bidirectionally Coax still shared among 100’s of users (500)Coax still shared among 100’s of users (500) Multiple content providers, unbundling?Multiple content providers, unbundling?

Fiber or coaxFiber or coax

coaxcoax

50 MHz50 MHz500 MHz500 MHz

5-40 MHz5-40 MHz

??


Packet UnbundlingPacket Unbundling

Single fiber/LT controlled by one service providerSingle fiber/LT controlled by one service provider SBC example: FCC allowed in Sept 2000 at LT onlySBC example: FCC allowed in Sept 2000 at LT only

Services unbundled at packet levelServices unbundled at packet level MAC in LT to control crosstalk problemsMAC in LT to control crosstalk problems

Dynamic spectrum managementDynamic spectrum management

CentralCentralOfficeOffice

Service 1Service 1

LTLTfiberfiber

twisted pair, DSLtwisted pair, DSL

Fiber, FTTHFiber, FTTH

Service 2Service 2

xtalkxtalk


The Main Technology IssueThe Main Technology Issue(a prime app for MU)(a prime app for MU)

Crosstalk – interference between linesCrosstalk – interference between lines Increases with frequency (data rate)Increases with frequency (data rate) Largest source of noise and performance lossLargest source of noise and performance loss Requires spectrum managementRequires spectrum management

Cross-section of cableAlso, space


xtalk coupling “resistance”xtalk coupling “resistance”

105

106

107

108

20

25

30

35

40

45

50

55

60

65

Freq (MHz)

cros

stal

k co

uplin

g (d

B)


Static Spectrum ManagementStatic Spectrum Management

Up (green) does not like down (yellow)Up (green) does not like down (yellow) Avoid overlap of yellow with green = static SMAvoid overlap of yellow with green = static SM

Fix allocations to compromise ILEC/CLECFix allocations to compromise ILEC/CLEC but xtalk/lines are different as are customers in each but xtalk/lines are different as are customers in each

locationlocation

ILECILEC

CLECCLEC


DYNAMIC SM = MU MethodsDYNAMIC SM = MU Methods

Line spectra/signals varied according to situationLine spectra/signals varied according to situation Data rates/symmetries of customersData rates/symmetries of customers Relative line lengthsRelative line lengths Topology of cable loopsTopology of cable loops

Large Improvements PossibleLarge Improvements Possible Migration Strategy to DSL/DSM of future Migration Strategy to DSL/DSM of future

necessarynecessary Line to packet unbundlingLine to packet unbundling Static to dynamic spectrum managementStatic to dynamic spectrum management


DSL Evolution GoalDSL Evolution Goal

ADSL VDSL VDSL- EFM VEFM

VDSL Evolution

6 10

25

100

0.65

25

100

0

20

40

60

80

100

120

4 km 2 km 1 km .3 km

TP Length

Dat

a R

ate

(Mbp

s)

Down

Up


Loop Plant of a Service ProviderLoop Plant of a Service Provider

Convenient pointsConvenient points RT, SAI (distribution node), pedestalRT, SAI (distribution node), pedestal

CentralOffice

MainDistributingFrame

equipment

SAI

feeder

distribution

pedestals

drop wire

Inside wire

Telephone Loop Plantcustomerpremises

20,000 to 1,500 to 200 to 4 to160,000 4,000 800 12 number of lines present at a site

22,000 feet 9,000 feet 3,000 feet 500 ft wire length to customer (90th percentile)

NID


Dynamic Spectrum Management StepsDynamic Spectrum Management Steps

Spectrum balancing – line unbundling Spectrum balancing – line unbundling For existing “line unbundling” situation where 3For existing “line unbundling” situation where 3rdrd party can make party can make

recommendations to individual lines, all or somerecommendations to individual lines, all or some Evolution to packet unbundling where situations are mixed pac/lineEvolution to packet unbundling where situations are mixed pac/line Implementation possible with current ADSL, VDSL systemsImplementation possible with current ADSL, VDSL systems

Vectoring – packet unbundlingVectoring – packet unbundling Lines coordinated at ONU side (or CO side) in terms of signals Lines coordinated at ONU side (or CO side) in terms of signals

placed on the line (packet unbunding)placed on the line (packet unbunding) Highest possible performance levels, shortest linesHighest possible performance levels, shortest lines Add-on (backward compatible) with ADSL, VDSLAdd-on (backward compatible) with ADSL, VDSL


Towards EthernetTowards Ethernet

DSLAMsDSLAMs Move toward customerMove toward customer Speeds go up and DSM usedSpeeds go up and DSM used Ethernet reused on top of DSLEthernet reused on top of DSL

Multiuser methodsMultiuser methods Spectrum balancingSpectrum balancing VectoringVectoring Combination of pairs to get 10, 100, or Combination of pairs to get 10, 100, or

10001000







Spectrum BalancingSpectrum Balancing

ILEC

CLEC

Lines report informationLines report information Helps with deployment, problem isolationHelps with deployment, problem isolation Can be used for DSMCan be used for DSM

Cent main recommends line spectraCent main recommends line spectra

Central DSM/DSL MaintenanceCentral DSM/DSL Maintenance


Need FiberPremium ServiceOrMaintenance necessary

Translation to Telco TermsTranslation to Telco Terms

Problem?

Data Rate?Cheap service

time of daytime of day as availableas available guaranteedguaranteed


DSLAMDSLAM MDFMDF&/or&/or

splitter(s)splitter(s)

ADSLADSL

ADSLADSL

ADSLADSL

Network MaintenanceNetwork Maintenance

POTSPOTSSwitchSwitch

MLTMLT

Telco’s want to knowTelco’s want to know prevent problemsprevent problems make $ make $

>$>$1B/rboc-ptt/yr1B/rboc-ptt/yr ! ! Spec ManagementSpec Management

DSLTDSLTADSLADSL

DynamicDynamicSpectrumSpectrum

ManagementManagement


Rate REGIONSRate REGIONS

Plot of all possible rates of linesPlot of all possible rates of lines UpstreamUpstream DownstreamDownstream

Any point in region is possible, but each with different spectraAny point in region is possible, but each with different spectra Varies for each cable and loop topologyVaries for each cable and loop topology Varies for each combination of desired (allowed) ratesVaries for each combination of desired (allowed) rates

RRshortshort

RRlonglong

Spectral pair 1Spectral pair 1

Spectral pair 2Spectral pair 2


Simple Example –PBOSimple Example –PBO

4 lines at 3000’ (7.8 Mbps upstream)4 lines at 3000’ (7.8 Mbps upstream) Line at 500, 1000, 1500, 2000, 2500’Line at 500, 1000, 1500, 2000, 2500’ Compare against best SSMCompare against best SSM

Very little coordination (power of line, rate)Very little coordination (power of line, rate)

500500 14.0 28.514.0 28.510001000 11.5 24.011.5 24.015001500 10.0 19.510.0 19.520002000 9.0 15.59.0 15.52500 8.5 11.02500 8.5 11.0

Ref length(SSM) iterwater.Ref length(SSM) iterwater.


So far, Static SMSo far, Static SM

PlansPlans 998 (USA) – more asymmetric998 (USA) – more asymmetric

997 (Europe) – more symmetric997 (Europe) – more symmetric

Flex planFlex plan Number of bands programmableNumber of bands programmable Start/stop frequencies programmableStart/stop frequencies programmable USA VDSL Standard – part 3 (allows DSM)USA VDSL Standard – part 3 (allows DSM)


998 with spectrum balancing998 with spectrum balancing

4 6 8 10 12 14 16 18 20 22 241

2

3

4

5

6

7

8

9Rate Region: 3000ft loops vs 1000ft loops: Upstream, Plan 998

Mbps

Mbp

s

0 5 10 15 20 25 30 35 40 45 5020

21

22

23

24

25

26Rate Region: 3000ft loops vs 1000ft loops: Downstream, Plan 998

MbpsM

bps

Line1500 ft versus 3000 ftLine1500 ft versus 3000 ft 26/6 on 3000’ while 30/22 on 1500’26/6 on 3000’ while 30/22 on 1500’ Static SM only 18/1.5 and 6/6Static SM only 18/1.5 and 6/6

DownUp


flex with spectrum balancingflex with spectrum balancing

Line1500 ft versus 3000 ft.Line1500 ft versus 3000 ft. 26/13 Mbps on 3000’, 52/26 Mbps on 1500’26/13 Mbps on 3000’, 52/26 Mbps on 1500’

5 10 15 20 25 30 352

4

6

8

10

12

14

16Rate Region: 3000ft loops vs 1000ft loops: Upstream, Flexible Plan

Mbps

Mbp

s

0 10 20 30 40 50 6020

21

22

23

24

25

26

27Rate Region: 3000ft loops vs 1000ft loops: Downstream, Flexible Plan

Mbps

Mbp

s

DownUp


VDSL and ADSLVDSL and ADSL

1 1.5 2 2.5 3 3.5 4 4.5 5 5.520

21

22

23

24

25

26

27

28

29

30

12000ft ADSL downstream rate (Mbps)

3000

ft V

DS

L do

wns

trea

m ra

te (M

bps)

ADSL vs VDSL: co-location at CP

1 1.5 2 2.5 3 3.5 4 4.5 5 5.59

10

11

12

13

14

15

16

17

18


4500

ft V

DS

L do

wns

trea

m ra

te (M

bps)


Yellow on short line acts like greenYellow on short line acts like green 9000’ ADSL (fig 6)9000’ ADSL (fig 6) 26/3 possible on 3000’ VDSL while ADSL runs 5/.5.26/3 possible on 3000’ VDSL while ADSL runs 5/.5.

Down 3000’ Down 4500’


VDSL and ADSL with Hdsl/IdsnVDSL and ADSL with Hdsl/Idsn

9000’ ADSL9000’ ADSL

Down 3000’ Down 4500’

0 0.5 1 1.5 2 2.5 320

21

22

23

24

25

26

27

28

29

30


3000

ft V

DS

L do

wns

trea

m ra

te (M

bps)


0 0.5 1 1.5 2 2.5 38

9

10

11

12

13

14

15

16

17

18


4500

ft V

DS

L do

wns

trea

m ra

te (M

bps)








Vectoring ResultsVectoring Results

500 1000 1500 2000 2500 3000 3500 4000 450010

20

30

40

50

60

70

80

90

Loop length (ft)

Da

ta r

ate

(M

bp

s)

Downs tream with Nois e A

997

998

V ec tored-V DS L

DownDown Up (see correction)Up (see correction)

500 1000 1500 2000 2500 3000 3500 4000 45000

10

20

30

40

50

60

70

80

Loop length (ft)

Dat

a ra

te (

Mbp

s)

Upstream with Noise A

997 998 Vectored-VDSL


Rate RegionsRate Regions

Last slide had all lines same lengthLast slide had all lines same length Rate Region allows tradeoffs between lines (1500, 1000)Rate Region allows tradeoffs between lines (1500, 1000)

0 50 100 1500

50

100

150

Data rate of user 1 (M bps )

Da

ta r

ate

of

us

er

2 (

Mb

ps

)

Rate regions (user 1 at 1500 ft, user 2 at 1000 ft)

No Data-Coordination

V ec tored-V DS L


How much better can we do?How much better can we do?(ADSL) (ADSL)

0 2000 4000 6000 8000 10000 12000 14000 160000

1

2

3

4

5

6

7x 10

7To

tal r

ate

Length (ft)

ADSL evolution

current cancel self-xtalkcancel all xtalk increase bit cap improve coding


Ultimate VDSLUltimate VDSL

0 2000 4000 6000 8000 10000 12000 14000 160000

0.5

1

1.5

2

2.5

3x 10

8

Tota

l rat

e

Length (ft)

VDSL evolution

current cancel self-xtalkcancel all xtalk increase bit cap improve coding ultra-DSL







EFM ExamplesEFM Examples

50 100 150 200 250 300 350 400 450 5000

50

100

150

200

250

300

350

Wire Length (m)

Da

ta R

ate

(Mb

ps)

Data Rates achievable over a CAT-5 private network

Vectoring within quad-TDDVectoring within quad Vectoring within bundle


EFM RangeEFM Range

2 lines, 100BT at 1 km2 lines, 100BT at 1 km 10BT at 1 km on one line easily10BT at 1 km on one line easily 4 lines, 100BT at 2 km4 lines, 100BT at 2 km

500 1000 15000

20

40

60

80

100

120

140

160

180

200

Wire Length (m)

Da

ta R

ate

(M

bps)

Data Rates achievable over a CAT-5 private network

Vectoring within bundle with 20dBm power Vectoring within bundle with 11.5dBm powerVectoring within quad with 20 dBm power Vectoring within quad with 11.5 dBm power


Ethernet ExamplesEthernet Examples

50 100 150 200 250 300 350 400 450 5000

2

4

6

8

10

12

14

16

18

20

Wire Length (m)

Da

ta R

ate

(G

bp

s)Data Rates achievable over a CAT-5 private network

VDSL Quad - 25 MHz Quad - 50 MHz Quad - 100 MHzQuad - 200 MHzQuad - 400 MHz


Copper has more bw than fiber?Copper has more bw than fiber?

50 line bundle in last segment of phone network50 line bundle in last segment of phone network 50 lines (200 Mbps/line) = 10 Gbps50 lines (200 Mbps/line) = 10 Gbps FTTH shares 2.5 Gbps among several homes in PON FTTH shares 2.5 Gbps among several homes in PON

architecturearchitecture Get bandwidth up in fiber connections to and Get bandwidth up in fiber connections to and

within network within network Copper in last mile has more BW than system can Copper in last mile has more BW than system can

handlehandle 100BT/100 Mbps to everyone, everywhere a 100BT/100 Mbps to everyone, everywhere a

phone line goes, is possible in the next decade.phone line goes, is possible in the next decade.


ConclusionsConclusions

Enormous wireline opportunity for multiuserEnormous wireline opportunity for multiuser Gains may be even larger than for wirelessGains may be even larger than for wireless Relatively stationary environmentRelatively stationary environment

The real broadbandThe real broadband At least 100 BT to everyone anywhere over a At least 100 BT to everyone anywhere over a

twisted pairtwisted pair DataData Voice, voice, voiceVoice, voice, voice VideoVideo

Welcome to the broadband age in this century Welcome to the broadband age in this century


Parts 3 and 4: Outline/ScheduleParts 3 and 4: Outline/Schedule

2:00-2:452:00-2:45 MU TheoryMU Theory 2:45-3:302:45-3:30 channels for wirelinechannels for wireline 3:30-4:00 3:30-4:00 CoffeeCoffee 4:00-4:304:00-4:30 DSL and Ethernet archDSL and Ethernet arch 4:30-5:154:30-5:15 Multiuser improvementsMultiuser improvements


ReferencesReferences1)1) T. Starr, J. Cioffi, and P. Silverman, T. Starr, J. Cioffi, and P. Silverman, Understanding Digital Subscriber Line TechnologyUnderstanding Digital Subscriber Line Technology, Prentice-Hall, Upper , Prentice-Hall, Upper

Saddle River, NJ, 1999.Saddle River, NJ, 1999.2)2) S. Verdu, S. Verdu, Multiuser DetectionMultiuser Detection, Cambridge Press, UK, 1998., Cambridge Press, UK, 1998.3)3) C. Aldana and J. Cioffi, “Channel Tracking for MISO Systems using EM Algorithm,” ICC 2001, Helsinki, Fin, C. Aldana and J. Cioffi, “Channel Tracking for MISO Systems using EM Algorithm,” ICC 2001, Helsinki, Fin,

http://cafe.stanford.edu/people/cioffi/dsm/channelpap/icc2001.pdfhttp://cafe.stanford.edu/people/cioffi/dsm/channelpap/icc2001.pdf4)4) C. Zeng, C. Aldana, A. Salvekar, and J. Cioffi, “Crosstalk Identification in xDSL Systems,” C. Zeng, C. Aldana, A. Salvekar, and J. Cioffi, “Crosstalk Identification in xDSL Systems,”

http://cafe.stanford.edu/people/cioffi/dsm/channelpap/jsac01.pdfhttp://cafe.stanford.edu/people/cioffi/dsm/channelpap/jsac01.pdf, August 2001 IEEE JSAC., August 2001 IEEE JSAC.5)5) G. Ginis and J.M. Cioffi, "Vectored-DMT: A FEXT CancellingModulation Scheme for Coordinating Users," ICC G. Ginis and J.M. Cioffi, "Vectored-DMT: A FEXT CancellingModulation Scheme for Coordinating Users," ICC

2001, Helsinki, Finland,pp. 305-309.2001, Helsinki, Finland,pp. 305-309.6)6) A. Duel-Hallen, "Equalizers for Multiple Input/Multiple Output Channelsand PAM Systems with A. Duel-Hallen, "Equalizers for Multiple Input/Multiple Output Channelsand PAM Systems with

Cyclostationary Input Sequences," IEEE J. Sel. AreasCommun., vol. 10, no. 3, pp. 630-639, April 1992.Cyclostationary Input Sequences," IEEE J. Sel. AreasCommun., vol. 10, no. 3, pp. 630-639, April 1992.(Generalizes infinite length MMSE-DFE's derived with spectralfactorization to MIMO case.)(Generalizes infinite length MMSE-DFE's derived with spectralfactorization to MIMO case.)

7)7) A. Duel-Hallen, "Decorrelating Decision-Feedback Multiuser Detector forSynchronous Code-Division Multiple-A. Duel-Hallen, "Decorrelating Decision-Feedback Multiuser Detector forSynchronous Code-Division Multiple-Access Channel," IEEE Trans. Commun.,vol. 41, no. 2, pp.285-290, Feb. 1993.(Zero forcing DFE solution.)Access Channel," IEEE Trans. Commun.,vol. 41, no. 2, pp.285-290, Feb. 1993.(Zero forcing DFE solution.)

8)8) J. Yang and S. Roy, ``Joint Transmitter-Receiver Optimization forMulti-Input Multi-Output Systems with J. Yang and S. Roy, ``Joint Transmitter-Receiver Optimization forMulti-Input Multi-Output Systems with Decision Feedback,'' IEEETransactions on Information Theory, vol. 40, no. 5, pp. 1334-1347,September Decision Feedback,'' IEEETransactions on Information Theory, vol. 40, no. 5, pp. 1334-1347,September 1994.(Showed that minimizing the decision feedback error is equivalent toachieving the mutual information.)1994.(Showed that minimizing the decision feedback error is equivalent toachieving the mutual information.)

9)9) G. J. Foschini, G. D. Golden, R. A. Valenzuela and P. W. Wolniansky,``Simplified Processing for High G. J. Foschini, G. D. Golden, R. A. Valenzuela and P. W. Wolniansky,``Simplified Processing for High Spectral Efficiency WirelessCommunication Employing Multi-Element Arrays,'' IEEE Journal onSelected Spectral Efficiency WirelessCommunication Employing Multi-Element Arrays,'' IEEE Journal onSelected Areas in Communications, vol. 17, no. 11, pp. 1841-1852,November 1999.(A zero-forcing GDFE combined Areas in Communications, vol. 17, no. 11, pp. 1841-1852,November 1999.(A zero-forcing GDFE combined with ordering.)with ordering.)

10)10) M. K. Varanasi, ``Decision Feedback Multiuser Detection: A SystematicApproach,'' IEEE Transactions on M. K. Varanasi, ``Decision Feedback Multiuser Detection: A SystematicApproach,'' IEEE Transactions on Information Theory, vol. 45, no. 1,pp. 219-240, January 1999.(Asymptotic analysis (high SNR) of decision Information Theory, vol. 45, no. 1,pp. 219-240, January 1999.(Asymptotic analysis (high SNR) of decision feedback and issues ofordering.feedback and issues ofordering.


More ReferencesMore References

11)11) N. Al-Dhahir and A. H. Sayed, ``The Finite-Length Multi-Input Multi-OutputMMSE-DFE,'' N. Al-Dhahir and A. H. Sayed, ``The Finite-Length Multi-Input Multi-OutputMMSE-DFE,'' IEEE Transactions on Signal Processing, vol. 48, no. 10,pp. 2921-2936, October 2000.IEEE Transactions on Signal Processing, vol. 48, no. 10,pp. 2921-2936, October 2000.

12)12) M. L. Honig, P. Crespo, K. Steiglitz, "Suppression of Near- and Far-EndCrosstalk by M. L. Honig, P. Crespo, K. Steiglitz, "Suppression of Near- and Far-EndCrosstalk by Linear Pre- and Post-Filtering," IEEE JSAC, vol. 10, no. 3,April 1992, pp. 614-629.Linear Pre- and Post-Filtering," IEEE JSAC, vol. 10, no. 3,April 1992, pp. 614-629.(MIMO MMSE linear equalizers.)(MIMO MMSE linear equalizers.)

13)13) A. Sendonaris, V. V. Veeravalli, "Joint Signaling Strategies forApproaching the Capacity A. Sendonaris, V. V. Veeravalli, "Joint Signaling Strategies forApproaching the Capacity of Twisted-Pair Channels," IEEE Tran. Commun.,vol. 46, no. 5, May 1998, pp. 673-685.of Twisted-Pair Channels," IEEE Tran. Commun.,vol. 46, no. 5, May 1998, pp. 673-685.

14)14) R.S. Cheng and S. Verdu, "Gaussian multiaccess channels with ISI: Capacityregion and R.S. Cheng and S. Verdu, "Gaussian multiaccess channels with ISI: Capacityregion and multiuser water-filling". IEEE Trans. Info. Th. IT-39, pp773-783, May 1993.multiuser water-filling". IEEE Trans. Info. Th. IT-39, pp773-783, May 1993.

15)15) W. Yu, W.Rhee, S. Boyd, and J. Cioffi, "Iterative Water-filling for Vector Multiple Access W. Yu, W.Rhee, S. Boyd, and J. Cioffi, "Iterative Water-filling for Vector Multiple Access Channel," IEEE International Symposium on InformationTheory 2001.Channel," IEEE International Symposium on InformationTheory 2001.

16)16) W. Yu, G. Ginis,and J. Cioffi, "An Adaptive Multiuser Power Control Algorithm for VDSL," W. Yu, G. Ginis,and J. Cioffi, "An Adaptive Multiuser Power Control Algorithm for VDSL," Submitted to JSAC. Also T1E1.4-2001/200R3Submitted to JSAC. Also T1E1.4-2001/200R3

17)17) W. Yu, G. Ginis, J. Cioffi, “optimum solution of broadcast communications problem,” in W. Yu, G. Ginis, J. Cioffi, “optimum solution of broadcast communications problem,” in preparation, 2001, preparation, 2001, [email protected]@dsl.stanford.edu..

18)18) K. Cheong, J. Choi, and J. Cioffi, “Multiuser Interference Canceler via Iterative Decoding K. Cheong, J. Choi, and J. Cioffi, “Multiuser Interference Canceler via Iterative Decoding for DSL Applications,” IEEE JSAC, Feb 2002, to appear, see also August 1999, ITU for DSL Applications,” IEEE JSAC, Feb 2002, to appear, see also August 1999, ITU contribution, SG15/Q4-NG-085.contribution, SG15/Q4-NG-085.

Documents

Part IV – Wireline Multiuser Examples