current frontiers in wireless communicationswcnc2009.ieee-wcnc.org/downloads/gerhard.pdf · tu...

Vodafone Chair Mobile Communications Systems, Prof. Dr.-Ing. G. Fettweis

Current Frontiers in Wireless Communications: Fast & Green & Dirty

Gerhard Fettweis

TU Dresden Gerhard Fettweis Slide 2

TM

Chair and Its Partners

32 Ph.D. students25+ Ms students4 sen. scientists1 post-doc1 professor1 project mgr2 secretaries4 engineers

ProjectsSponsors

IPP 2008Oct-1

Scientific:44 Ph.D. grads175+ Ms. grads500 publications40+ patents

Innovation:8 spinouts200 engineers

Funding:€

+35M Chair€

+40M VC€

250M projects.

Numbers


The

Vodafone Chair‘s

Startup

History

2002

2007

1999

OnDSP™

based WLAN chip-sets

2000

UMTS/3G network optimization and planning

2003

LTE FDD & TDD test mobile

2004

Module and reference board design

2005 MPSoC

semiconductor IP

2007

Wireless embedded technology

2008 Network performance measurement

2008

LTE Cellular Technology Provider

freedelity

2006


FAST


Embedded Mobile Memroy: Single-Chip Flash Memory Trend

100Gb

10Gb

1Gb

100Mb

10Mb

1Mb

100Kb

10Kb

1995

2000

2005

2010

2015

4Gb

16Gb8Gb


“The Wireless Roadmap”


Data Synchronization: Point-to-Point

100Gb/s

10Gb/s

1Gb/s

100Mb/s

10Mb/s

1Mb/s

100Kb/s

10Kb/s

1995

2000

2005

2010

2015

USB 1.0

USB 2.0

USB 3.0

UWB intention802.15.3c

Short links (1m)


Client Server Applications: WLAN

1995

2000

2005

2010

2015

Short links (1m)

WLAN (10m)802.11vht

802.11n802.11ag

802.11

802.11b

100Gb/s

10Gb/s

1Gb/s

100Mb/s

10Mb/s

1Mb/s

100Kb/s

10Kb/s


Coverage: Cellular

1995

2000

2005

2010

2015

Short links (1m)

Cellular (100m)

GSM GPRS

HSPA

HSDPALTE

WiMAX

WLAN (10m)

3G R99 / EDGE

LTE Advanced

100Gb/s

10Gb/s

1Gb/s

100Mb/s

10Mb/s

1Mb/s

100Kb/s

10Kb/s


The Wireless Roadmap

1995

2000

2005

2010

2015

Short links (1m)

Cellular (100m)

WLAN (10m)

100x

10x

ITRS Roadmap: Continues until 2020

Driven By Moore’s Law

100Gb/s

10Gb/s

1Gb/s

100Mb/s

10Mb/s

1Mb/s

100Kb/s

10Kb/s


The ITU “Van”

Diagram


2004: Integration Nightmare Roadmap of Wireless Standards into Handsets

2004 2005 2006 2007 2008 2009

Status Today

GSM/UM

TS

Bluetooth

IrDA

+ WiFi 802.11b

+ DVB-T/H

+ WiM

ax+ UWB Wireless USB

+ NFC

+ WiFi 802.11g

+ WiFi 802.11n

+ 802.20

+ ZigBee

WiFiIEEE 802.11b: 11Mb/s wireless LAN @ 2.4GHz (up to 100m)IEEE 802.11a/g: 54Mb/s wireless LAN @ 2.4/5GHz (up to 100m)IEEE 802.11n: 250Mb/s wireless LAN @ 5GHz (up to 30m)

UWB (IEEE 802.15.3a): 480Mb/s wireless USB2.0 (typ. 1m)WiMax (IEEE 802.16d/e): ~10Mb/s broadband wireless accessNFC: Near Field Communications (RF-ID, wireless payment,…)

ZigBee: (IEEE 802.15.4)Sensor networks, remote control

BluetoothVersion 2: TBD?

+ FM Radio

+ GPS

+ Galileo

+ MediaFlo


2009: Integration Cleanup Roadmap of Wireless Standards into Handsets

2007 2008 2009 2010 2011 2012

Status Today

GSM/UM

TS

Bluetooth

IrDAFM Radio

WiFi 802.11bg

GPS

+ WiM

ax+ W

iFi 802.11n+ Galileo

- FM Radio

- BlueTooth

Status Tomorrow

LTE / WiM

AX

(UWB+??)

(GPS/Galileo)

(WiFi 802.11)

- IrDA

Loosers: MediaFlowDVB T/HNFCZigBee802.20

UWB


The Only Wireless Features We Need?

Cellular Connectivity Fast

Broadband Local Connectivity Fast

Positioning


How to Achieve “FAST”

in Cellular


Shaping the SINR Distribution

Active „shaping“

of SINRInterference CancellationPower Control

AdvantagesHigh average SINR

High spectral efficiencyEnabler for MIMO

Small VarianceHigh grade of fairness

no no


Fairness & Data Rate & Spectral Efficiency

0.5

0.4

0.3

0.2

0.1

0.0

-10 -5 0 5 10 15 20 25 30SIR in dB

Reuse 1Power Control

E[SIR] = -0.2dB

Reuse 1Power Control

10 Interferers cancelledMacro/Distributed MIMO

E[SIR] = 8.1dB

pdf

of SIR

fairn

ess

Interference Cancellation: Fairness & High Data Rate


CoMP: Coordinated Multi-Point

We thus believe that next generation systems will include multi-cell cooperative signal processing (“network MIMO” or CoMP):


Roadmap View

1st/2nd generation 3rd generation 4th generation

•

Interference avoidance through high reuse factors

•

Interference shaping and exploitation through distributed MIMO and relaying

•

Interference suppression through classical MIMO


Potential Gains

of CoMP

Uplink Downlink

Okumura-Hata pathloss model, ITU pedestrian ALink-to-system mapping (MIESM), 8 MCS schemesSpectral eff. losses through guard bands / intervalsAssuming perfect channel est., 2 rx ant. per eNB

Linear joint transmission, assuming perfect channelknowledge at the eNBs

2 tx ant. per eNB


Limits in Clustered

Virtual

MIMO A Graph Theory

Approach

We can easily observe how many interferers would have to be perfectly cancelled for a user at any location within a cell, to achieve a capacity target:

Target 3 bit/s/Hz/sector Target 4 bit/s/Hz/sector

Note that we are assuming perfect interference cancellation (optimistic), but do not take into account increased diversity (pessimistic)


Spectral Efficiency

0,1 0,3 0,51,2

3

10

0123456789

10

GSM EDGE HSPA LTE EASY-C Theory

SpectralEfficienncybit/s/Hz/sector GAP

License Cost (GER)1Hz ~ EUR 1000100Mb/s/sector required:- GSM: 1GHz €1T-

LTE: 100MHz €100B-

Theory: 10MHz €10B

20 YEARSOf Engineering

1987 - 2007

20 further YEARSOf Engineering

2007-2027?

Enablers for Ambient Services & Systems Part C: Wide Area Coverage

EASY-C Update

24

Project Partners Coordinator: Gerhard Fettweis

Rosenheim

Dresden

Nürnberg

UlmStuttgart

Darmstadt

Paderborn

Bonn

Düsseldorf

Berlin

München

Aachen

Mainz

Volume:€ +47M project€ +27M funding

http://www.infineon.com/cgi-bin/ifx/portal/ep/home.do?tabId=0

25

Current View on Network MIMO

System partitioningReducing

Backhaul

/ Infrastructure

Aspects

Scheduling

Synchronization

in time / frequencyChannel estimation

&Obtaining

transmitter-

side

CSI at eNBs

Impact of network

MIMO

on higher

protocol

layers

See the following challenges connected to network MIMO:

26

Project Workflow

2.1 Specification

1.1 Algorithm & Concept Exploration

1.2 Algorithm Classification & Selection

2.2 Implementation

2.3 Lab Test

2.4 Field Test

3.1 Specification

3.2 SoC Architecture

3.3 Implementation

3.4 Demonstrators

1.3 Assessment & Dissemination

WG 1

Algorithms & Concepts

WG 2Technology Test Bed

WG 3Hardware Architecture

Working Groups Alcatel-LucentBNetzADt. TelekomEricssonFhG HHIIFX/ComneonKathreinNXPQualcommRadioplanSignalionTESTU DresdenUbidyneUni PaderbornVodafone

27

Mini Out-to-Indoor Testbed Dresden TUD Indoor Test, Southern View

Two sectors are installed on the roof of TUD building:

IndoorTerminals

Microwave radio link LAN Network ConnectionOur Tower

Amateur RadioTower

BARKHAUSEN Building

© Microsoft Live

IndoorNLOSHallwayMeasurements

28

Lab Site:2 sites at the chairAntenna: 1700-2700MhzMicrowave link between the sites

Mobile Lab UE:Sorbas UE12V BatteryNotebook

Mini-Testbed Dresden TUD Lab Test

29

Field Test Berlin Overview

In Berlin, a second test bed is beingset up, with a focus on services and applications

AirlaserAirl

aser

optical fiber network

1

23

4

T-Labs TU Berlin

HHI

30

Cellular After 2015

© Google Earth

Hbf-Süd

Karstadt

Postplatz

Lennéplatz

Mitte

Kongresszentrum

Fritz-Förster-Pl.

Strassburger Pl.

WTC

HbfICC 2009Dresden

31

Testbed Dresden Field Test

LTE+ antennas co-located at real 3G sites (downtown, hight of antennas 30-55m)

Support from project partner(Vodafone, T-Mobile)

Backhaul realized withMotorola Canopy PTP600 system (250 Mbit/s TDD system)


Additional Challenges:“Lessons Learned”


OFDM for Downlink CoMP

t = t0

-τ t = t0

-τ

t = t0 t = t0

τ

≈

d/cUse CP to compensate?LTE: d=360m

d distance between cooperating base stations


Carrier Phase Offset, Phase Noise

Carrier Phase Offset (CPO)Caused by LO imperfections

Phase Noise (PN)Caused by LO jitter due to non perfect sine generation

CoMP PN increased by 3-5dB

BPF LNA90°

PLL

LPF

LPF VGA

VGA ADC

ADC

PLL~

Rx DFE

AGC

Rx AFESRC

SRC

BPF PA

Tx AFE

90°

DAC

DAC

PLL PLL~

Tx DFESRC

SRCTS

,fS

,BSTSN

,fSN

,BSN TC

,fC

,BC

h(t,τ) Doppler Spread

θ

‐θ

©

Vincent Kotzsch, 2008


Sampling Clock Offset

Sampling Clock Offset (SCO)Sampling offset between ADC and DACCaused by LO imperfectionsRange: 10-5 - 50ppm related to sampling rateCoMP “negligible asynchronous OFDM”

BPF LNA90°

PLL

LPF

LPF VGA

VGA ADC

ADC

PLL~

Rx DFE

AGC

Rx AFESRC

SRC

BPF PA

Tx AFE

90°

DAC

DAC

PLL PLL~

Tx DFESRC

SRCTS

,fS

,BSTSN

,fSN

,BSN TC

,fC

,BC


©



Carrier Frequency Offset

Carrier Frequency Offset (CFO) Continuously phase shift over timeCaused by LO-imperfections and DopplerRange: 10-5 - 50ppm related to fCCoMP “artificial Doppler”

BPF LNA90°

PLL

LPF

LPF VGA

VGA ADC

ADC

PLL~

Rx DFE

AGC

Rx AFESRC

SRC

BPF PA

Tx AFE

90°

DAC

DAC

PLL PLL~

Tx DFESRC

SRCTS

,fS

,BSTSN

,fSN

,BSN TC

,fC

,BC


fC

fC

+ Δ

2πfC

TS

2πfC

2TS

©



Requirement “FAST”

will not end soon


GREEN

cool


The Server Farms Are Growing

Moore’s law for logic:5x every 5 yearsMoore’s law for flash10x every 5 years

RESULT:2x power consumption every 5 years


In 2007 the Energy supply of ICT produced CO2

-output at level of 25% of

worldwide cars

The Challenge

Classic Internet (Computing & Mobile)

Cisco IP Traffic Forecast 2008

Internet of Things(networked sensors)

2007 2017


Energy Costs= Invest

Energy Costs= Personnel2007

Paradigm Change

CellularCustomers (Mio.)

200

400

600

1996

2008

1996

2008

1‘000

2‘000

3‘000

ComputingInternet-Server (Mio.)

QuelleISC

QuelleGSM World


Server farms & telco infrastructureCurrently 3% of world electric energy consumptionIncreasing by 16-20% / yearDoubling world el. energy consumption by 2030 driven by ICT

ICT: 10% of el. energy demand within industrialized nations900 Bill.. kWh / year = Central and South AmericasWorldwide proliferation: 40% of world el. energy production

Dramatic improvement in energy efficiency needed !

Energy Demand & CO2

of ICT


Cellular: What Do We Know

Cellular networks: 0.5% of world-wide electrical energyHandsets: 1% of total cellular energy consumptionNetwork: 99% of total cellular energy consumption

Running the network:Expected energy bill: 3x (200%) over next 7 years80% of energy consumed at base station site

50% for coolingE.g. UMTS CDMA: 25% power in “pilot pollution” !!!“Always on” the wrong strategy?!

Need of “border-crossing” optimization: System Engineering


CoordinatorProf. Gerhard Fettweis

45

Key Facts of Cool Silicon

Partners–

Companies•

Currently around 40 companies involved–

Universities•

TU Dresden•

TU Chemnitz•

HTW Dresden–

Research Institutes

Money–

EUR 100M funding–

EUR 150M total volume

Duration: Feb-2009 to Feb 2014


How to Achieve “GREEN”in Handsets (& Base Stations)


LTE FDD & TDD / WiMAX

Single-Chip SDR: Tomahawk –

Block-Diagram

32

3232

DC_570TRISC No. 1

DC_570TRISC No. 2

GPIO (8)

32 32

32

VGAIF

STREAMIF PCI-EXPRESS

SLAVE SLAVE MASTER MASTER SLAVE

FPGA-BRIDGE

32

COREMANAGER

SLAVEMASTER

SLAVE MASTER

DMADMA

32

MASTER

32

INTBUS (32 BIT)

MASTER MASTER

32 32

SLAVE

MASTER

32

SLAVE

32

VDSPFXT16

VDSPFXT16

32

SLAVE

VDSPFXT16

32

SLAVE

VDSPFXT16

32

SLAVE

RKDSP

32

SLAVE

RKDSP

32

SLAVE

LDPC

32

SLAVE

DEBLOCKER

32

PLD-ApplicationsTensilica

MASTER MASTER

Dresden Silicon

Vodafone Chair

DDR-RAM 16/32 BIT

32

SLAVE

DDR-RAM 16/32 BIT

32

SLAVE

DMA

SLAVE MASTER MASTER

32 32

32

UART 2

32

UART 1

32

SLAVE

Entropy

32

SLAVE

StreamParser

DDR-RAM 16/32 BIT

32

SLAVE

DMA

MASTER

32

MASTER

32

ScratchPad

32

SLAVE SLAVE

32

ASIC-Architectinc

52 4 4338 42 42 913742

EXTBUS (32 BIT)

SLAVE

VDSPFXT16

32

SLAVE

VDSPFXT16

32

BOOT

2

Our Testchip”TOMAHAWK”: running silicon Jan 18, 2008

TensilicaDiamond

212GP

TensilicaDiamond

212GP


LTE FDD/ TDD/ WiMAX

Single-Chip SDR: Tomahawk -

Die Photo

STA LDPC Decoder/

DeblockerASIP

STA Vector DSP

2x STA SIOUX

Core Manager

3x DDR Controller

10 mm

10 mm2x XtensaDC212GP

Scratchpad

PLL

PLL

PLL

Silicon on Jan 18 2008

In 45 nm CMOS:Complete LTE BB

< 20mm2

< 200mW

130nm UMC 57M transistors


Area & Power Efficiency

1.

MIMO SVD ASIC2.

Consumer RISC3.

Multimedia DSP4.

FFT Processor5.

RISC CPU with Media Processor

6.

Communications DSP7.

CAM LSI8.

Video Stream Multi-

Processor

9.

Hearing Aid DSP

Source: Markovic et. al., Power and Area Minimization for Multidimensional Signal Processing, IEEE J. Solid-StateCircuits, vol. 42, no. 4, pp. 922-934, April 2007. Results scaled to 90 nm, operations are 12 bit add equivalents

1 2

3

4

5

67

8

9 by 1


How to Achieve “GREEN” in Networks


Some Issues

Network topologyNetwork architecture

Network componentsNetwork interconnections

Network supported featuresNetwork delivered bandwidth


DIRTY RF


Dirty RF

Picking up “dirt” Nonlinear

LNAFeedthrough

Coupling

Phase noise

Aperture

JitterAmbiguity

I/Q ImbalanceRRC mismatch

Flicker NoiseDigital noiseNonlinear

PADSP:LivingWithDirtyRF


Limited Tx-Rx Isolation due to miniaturization and frequency agility→ Tx Leakage (TxL)→ Strong out-of-band interference in Rx branch

Transmit Leakage in FDD and Direct Conversion

Approaches for Solution:

Problem: Tx

Leakage in FDD Terminals

Additional bandpass filterAdaptive filter in parallel to duplexerDirty RF: Compensation of analog impairments by digital signal processing+ Reconfigurable / standard independent / relaxed RF requirements

-

Limited reconfigurability-

Increased analog complexity

DL signal


Dup

lexe

r

Tx

Leakage in Zero-IF Receivers

Nonlinearity of I/Q down converter Intermodulation product 2nd order of Tx Leakage (TxL-IM2)

Low freq. TxL-IM2 interfering desired, down converted DL signal

Tx

Leakage intermodulation

products 2nd order (TxL-IM2)

DL signal

TxL- IM2

TxL channel

DC-


Antenna nearfield distorted bymetal interrupter moved withindistance [0.036, 0.303] m to the antenna

Tx-Rx

Isolation

Measurement

with

UMTS SAW Duplexer

B7632 (EPCOS AG)

UL-Band DL-Band

B

Frequenz [GHz]

Tx-R

x Is

olat

ions

däm

pfun

g [d

B]

1.9 1.95 2 2.05 2.1 2.15 2.2-70

-65

-60

-55

-50

meanmin / max

Frequency

[GHz]

Tx-R

xis

olat

ion

[dB

]

Tx-Rx isolation affected by nearfielddistortionsOnly small variations in UL-Band (ca. 2.2 dB)TxL Estimation must be adaptive


SNR loss

due

to TxL

-5 0 5 10 15 20 25 30

0

2

4

6

8

10

12

14

16

18

20

γ̃TxL[dB]

∆γ̃w.r.tw/ oTxL[dB]

w/o TxL

CmpGenie TxL

CmpML, τ=3.5LMS

τ=3.5meas.τ=1.5

dig. TxL

Cmp

required

TxL

negligible

analog. TxL

Cmp

req.

OFDM susceptible to TxL for γTxL < 30dBdigital TxL compensationsuitable for γTxL > 0dBTxL can be mitigated digitally up to 30 dB

Simulation Parameters:DL / UL: 802.11a, 16QAMDL channel: HiperLAN A CSF EQ in TxL Est.analog DC-1

ADC: 8-bit lin. mid-rise, η=2TxL: - TxL ch: 6-tap exp PDP

and meas. IR- TxL SIR γTxL = 10dB- no TxL I/Q mismatch

TxL Est: - NB=4000,

ML reaches almost Genie Cmp. limit, but suffers from high min. SNR lossLMS performance stronglydepending on TxL channel property


Phase Noise and Clippping

-1.5 -1 -0.5 0 0.5 1 1.5-1.5

-1

-0.5

0

0.5

1

1.5

In

Qua

• Phase Noise:• Kalman

Tracking• Complete Sync

-1.5 -1 -0.5 0 0.5 1 1.5-1.5

-1

-0.5

0

0.5

1

1.5

InQ

ua

• Clipping:• Analogue PAPR• Saleh

Model• AM/PM distortion

-1.5 -1 -0.5 0 0.5 1 1.5-1.5

-1

-0.5

0

0.5

1

1.5

In

Qua

• Clipping & PN:• Rate


Phase Noise in OFDM


Setup:IEEE 802.11a SISOExponential PDP, 8 taps64-QAM f = 4GHz, IBO = 0dB

Rate under Phase Noise & Clipping

-10 0 10 20 30 400

1

2

3

4

5

6

SNR [dB]

Rat

e [b

its]

no distortionno compensationIa

= 0.2, ICI1

Ia

= 0.4, ICI2

Ia

= 0.6, ICI3

Ia

= 0.8, ICI4


Many Further Issues

“Estimation and Detection”

algorithm designNonlinearitiesPhase noiseI/Q imbalanceSampling jitterTransmit leakage…


Conclusions


FAST increasing data transmission rates

GREEN much lower-power “cool communications”

RF impairment estimation with DIRTY RF approach

We need much more further research !


Thanks !

Thank you Vodafone for the continued support of the chair

www.vodafone-chair.com

http://www.vodafone-chair.com/

current frontiers in wireless communicationswcnc2009.ieee-wcnc.org/downloads/gerhard.pdf · tu...

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