GCOE Workshop on Advanced Wireless Signal Processing and Networking Technology Tohoku University, Aug Opening Remarks.

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GCOE Workshop on Advanced Wireless Signal Processing and Networking Technology Tohoku University, 20-21 Aug. 2008

Opening Remarks

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Fumiyuki Adachi

Wireless Signal Processing & Networking (WSP&N) Lab Wireless Signal Processing & Networking (WSP&N) Lab.

Dept. of Electrical and Communications Engineering, Tohoku University, Japan

E mail: adachi@ecei tohoku ac jp E-mail: [email protected] http://www.mobile.ecei.tohoku.ac.jp/

OUTLINE

Global COE Program

Challenge for 4G Wireless

08/20/2008 FA/Tohoku University 1

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5 ea Global COE P og am

5-year Global COE Program

Tohoku University has a long history of outstanding

research, e.g., Yagi-Uda antenna and optical

communications technology.

Based on our strong background of research and education,

our group was selected 5 years ago as COE of its first phase (April 2002~March 2007)

phase (April 2002~March 2007).

Now, we started COE program (global COE) called “Center

of Education and Research for Information Electronics of Education and Research for Information Electronics Systems” (April 2007~March 2012).

Program director

&

research Research Research group leader ν-QI school 08/20/2008 FA/Tohoku University 2 group leader group leader Prof. K. Edamatsu group leader Prof. M. Kameyama ν QI school leader Prof. M. Kawamata Prof. F. Adachi

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Ed

ti

& R

h

Education and research are equally important.

Education & Research

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Education in ν-QI school (Quadruple I: School of Interdisciplinary, International, Industry-academic Interchanges)

Intensive NT/IT research/

NT/IT Education & Research Center Research Education NT/IT ν-Q I School Ranked Research Intelligent Information RA Group Network Super Grants Student-Organized International Information/ Device/ Fundamentals Systems p Research p Internships International Conferences World-Class Research Fostering World-Class Young Researchers Fundamentals 08/20/2008 FA/Tohoku University 3

Long history of original research on information electronics and strong collaborative education by 3 departments

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z Focus on systems research z 3 research groups (C) Intelligent Information _g _p (23 members) z Focus on research

into optical and

(B) Network (7) Systems (4) wireless networking technology (A) Information D i (7) Devices /Fundamentals (12) z Invite overseas researchers to int. Workshops /seminars symposia z Hold small-scale workshops/seminars Int. ll b ti I t /seminars 08/20/2008 FA/Tohoku University 4 for deeper discussions collaboration Mini conferences Int. symposia

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Groups A~C will work in close cooperation to develop thep p p

fundamental technologies necessary for human-oriented global networks. IT zClose zClose Close cooperation among three groups Close cooperation among three groups g p zFundamental /practical lectures for g p zFundamental /practical lectures for PhD students zBroad knowledge and PhD students zBroad knowledge and NT outlook outlook 08/20/2008 FA/Tohoku University 5

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Wireless

Group A (led by Prof. Keiichi Edamatsu) develops

Semiconductors, storage, optical and display devices with super high

G L d

performance (i.e., high density, high speed, high functionality, low power consumption, etc.)

The fundamentals of information communication devices and theories behind the

information systems to be used in 10 years time

Prof. Kunio Sawaya Group Leader

Prof. Fumiyuki Adachi

information systems to be used in 10 years time.

Group B (led by Prof. Fumiyuki Adachi) develops

Super-high-speed coherent optical communication technology Super-high-speed coherent optical communication technology,

broadband wireless signal processing technology, secure network architectures, and communications protocols, as well as optical and wireless technologies and distributed networks.

The target data rate of optical communications is 1~10 Tbps using optical TDM/WDM technology and the wireless data rate should be as optical TDM/WDM technology and the wireless data rate should be as high as 100 M~1 Gbps over a hostile wireless propagation channel.

Group C (led by Prof. Michitaka Kameyama) develops

Intelligent communications technology with a more than tenfold improvement in

recognition capability and performance

Intelligent information systems with autonomous recognition and prediction of

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Ch ll

f 4G

Challenge for 4G

Every one wants to communicate instantly with anyone, any time,y y y , y ,

from anywhere

Arrival of ubiquitous society: communication is available everywhere This is only possible by wireless Wireless is indispensable in our This is only possible by wireless. Wireless is indispensable in our

forthcoming ubiquitous society

Every 10 years, a new wireless technology has come up and

h d i

changed our society

1980’s: from “point-to-point” to “anytime, anywhere”

communication communication

1G systems (analog)

1990’s: from voice to “narrowband data + voice”

2G systems (digital) Access to the Internet

2000’s: Æ“wideband data + voice” 2000 s: Æ wideband data + voice

3G systems and then 3.5G systems (high speed packet)

2010’s: Æ “broadband data + voice”

4G systems

Roaming across heterogeneous networks

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3 5G d

3 9G

(LTE)

S

t

3.5G and 3.9G (LTE) Systems

3G systems will continue to evolve to meet the

demands of (internet-related) broadband wireless

services and substantially strengthen its downlink

data rate capability.

High-speed downlink packet access (HSDPA), calledHigh speed downlink packet access (HSDPA), called 3.5G systems of ~14Mbps/5MHz, started in Japan in 2006.

Even 3.5G of ~14Mbps will sooner or later become

insufficient.

A 3 9G will appear to provide broadband services of

A 3.9G will appear to provide broadband services of

50~100Mbps/20MHz using the 3G bands.

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E

l ti

I t 4G

Evolution Into 4G

4G systems are required to provide much faster services of

a peak data rate of 100M~1Gbps.

ITU allocated the spectrum for 4G systems in Dec. 2007.

450~470MHz (20MHz), 790~806MHz (16MHz), 2.3~2.4GMHz

(100MHz), 3.4G~3.6GHz Global use (200MHz)

a point_to _4G

Narrowband

Era WidebandEra BroadbandEra

2G ~64kbps 1G ~2.4kbps ype _timedi 3G ~2Mbps 4G 100M~1Gbps 0G -to-point 50~100Mbps Broadband wireless rvice t Mul t ~14Mbps Voice only 3G LTE Se r V oice IMT -2000 HSDPA 08/20/2008 FA/Tohoku University 9 1980 1990 2000 Year V 2010 We are here

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T

h i

l I

f

4G

Technical Issues for 4G

For a peak data rate of ~1Gbps/BS, there are two

For a peak data rate of 1Gbps/BS, there are two

important technical issues to address.

Spectrum efficiency

The available bandwidth in the global frequency band is

200MHz only. This must be shared by several operators. 1Gbps/100MHz is equivalent to >10bps/Hz/BS

1Gbps/100MHz is equivalent to >10bps/Hz/BS.

This target must be achieved in an extremely

frequency-selective wireless channel, where strong inter-symbol

i t f (ISI) i d d S d d li ti

interference (ISI) is produced. Some advanced equalization technique is necessary.

Transmit power Transmit power

Peak power is in proportion to “transmission rate”.

For a very high rate transmission, a prohibitively high transmit

power is required if the same communication range in distance is kept as in the present cellular systems.

To keep the transmit power the same as in the present To keep the transmit power the same as in the present

systems, fundamental change is necessary in wireless access network.

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S

t

Effi i

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Spectrum Efficiency Problem

In terrestrial wireless communications, the transmitted,

signal is reflected or diffracted by large buildings between transmitter and receiver, creating propagation paths having different time delays

different time delays.

For 1Gbps transmission, 1bit time length is equivalent to

the distance of 0.3 m. So, many distinct multipaths exist,

th b t l h i th h l f

thereby extremely enhancing the channel frequency-selectivity. Large obstacles d_-4 Local Transmitter _Local scatterers Transmitter Receiver Reflection/ 08/20/2008 FA/Tohoku University 11 diffraction

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The transfer function

of wireless channel is no longer constant

th i l 1

10

l gain

over the signal bandwidth. Challenge is to Channe0.1 l Challenge is to transmit broadband data close to 1 Gbps ith hi h lit 0.01 0 10 20 30 40 50 60 70 80 90 100 Frequency (MHz)

with high quality over such a severe frequency-selective 10 Frequency (MHz) n frequency selective channel. Giga-bit wireless 1 h annel gai n technology of >10bps/Hz/BS is necessary for 4G 0.1 C h

L=16 Uniform power delay profile

l-th path time delay=100l + [-50,50)ns

necessary for 4G.

0.01

0 1 2 3 4 5 6 7 8 9 10

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H

T A hi

1Gb

?

How To Achieve 1Gbps?

What is Giga-bit wireless technology for 4G?

What is Giga bit wireless technology for 4G?

Multi-access, HARQ, modulation,

MIMO, access network, …..

In 3.9G or 3G LTE, wireless downlink access will be based

on multi-carrier technique, e.g. OFDMA, while uplink access based on single carrier technique with FDE

based on single-carrier technique with FDE. FDMA ency Frequency-domain Signal Processing Time-domain Signal

?

f3 f2 f1 Frequ e OFDMA SC-FDMA g Processing

3 9G

4G

?

Time

1G

_CDMA # 3 Si l i OFDMA，SC FDMA

3.9G

TDMA Freq. 1 2 3 1 2 3 Freq. # 2# 3 Spreading d #1

3G

Single-carrier Code-domain FA/Tohoku University 13 08/20/2008 TimeFA/Tohoku University 13

F

2G

code#1

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T

it P

P bl

Transmit Power Problem

Data transmission of 100Mbps~1Gbps requires a

Data transmission of 100Mbps 1Gbps requires a

prohibitively high transmit power

Peak power is in proportion to “transmission rate” x “Peak power is in proportion to transmission rate x ff_c_c2.6

[Hata-formula]” where f_c is the carrier frequency.

Assume that the required transmit power for 8kbps@2GHz is

1Watt for a communication range of 1 000m 1Watt for a communication range of 1,000m.

The required peak transmission power for [email protected]

needs to be increased by 1Gbps/8kbps x (3.5GHz/2GHz)_y _p _p ₍ ₎2.6 ₌

535,561 times, that is, 536kWatt. Obviously, this cannot be

allowed.

T k

th 1W

th

i ti

To keep the 1W power, the communication range

should be reduced by

43 times(i.e., 1,000m

Æ

23 m

)

Æ

23 m

)

FA/Tohoku University 14 FA/Tohoku University 14

* M. Hata, “Empirical formula for propagation loss in land mobile radio services”, IEEE Trans. Veh. Technol., VT-29, pp. 317-325, 1980.

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Frequency-domain

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li

ti

(FDE)

Equalization (FDE)

1G, 2G and 3G used _Spreading

1G, 2G and 3G used

FDMA，TDMA，and

DS-CDMA, ti l All f Spreading code +GI S/P IFFT P/S MC-CDMA, OFDM Data Modulated sequence Transmit signal respectively. All of them are based on time-domain signal

+GI S/P IFFT P/S

DS-CDMA (a) Transmitter

time domain signal processing What signal i h ld b Spreading code

Σ

MC-CDMA, OFDM Despreading

processing should be used for 4G?

DS-CDMA with FDE can

-GI S/P FFT FDE P/S

Σ

Soft decision data sequence Received

signal

CDMA with FDE can remain as an important multiple t h i f IFFT _DS-CDMA q (b) Receiver

access technique for

4G wireless. Transmitter/receiver structure _{(DS- and MC-CDMA, OFDM)}

* F. Adachi, D. Garg, S. Takaoka, and K. Takeda, “Broadband

CDMA techniques,” IEEE Wireless Communications

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H

T A hi

1Gb

?

How To Achieve 1Gbps?

4G target of peak data rate is ~1Gbps, but the available

4G target of peak data rate is 1Gbps, but the available

bandwidth may be 100MHz in 4G (3.4~3.6GHz band).

1Gbps/100MHz/BS=10bps/Hz/BS

If we want to achieve this goal by multi-level modulation, 1024QAM is required.

However, the achievable BER performance severely degrades., p y g

16QAM 4QAM (2b /H ) 08/20/2008 FA/Tohoku University 16 16QAM (4bps/Hz) (2bps/Hz) 1024QAM (10bps/Hz)

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MIMO Multiplexing May Be A

S

i

Savior

Increasing the no

80

Increasing the no.

of antennas can

improve the

70

80

8 NxN MIMO (w/receive diversity)

improve the

spectrum efficiency

or can decrease the

50 60 6 7 8

o

a d

a

required transmit

power.

40 C (b p s/ H z) 5 4 6 5

p

20 30 C 4 3 2 10 2 N=1 0 0 10 20 30

Average total received E

s/N0 per receive antenna (dB)

G. J. Foschini and M. J. Gans, “On limits of wireless communications in a fading environment when using multiple antennas,” Wireless Personal Commun., Vol.6, No. 3, pp.311-335, Mar. 1998.

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However, MIMO Cannot Solve

P

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Power Problem

Links for broadband data services are severely

power- Links for broadband data services are severely power

limited.

Peak power is in proportion to “transmission rate” x “f_c2.6

[H t f l ]” h f i th i f

[Hata-formula]” where f_c is the carrier frequency.

Let’s consider the peak transmit power for [email protected] at

a communication range of 1,000m. We assume the required a co u cat o a ge o ,000 e assu e t e equ ed transmit power for 8kbps@2GHz is 1Watt.

The required peak transmission power is

b /8kb ( / )2 6 _h

1Gbps/8kbps x (3.5GHz/2GHz)2.6 ₌ _535,561 _{times, that is}

536kWatt. Obviously, this cannot be allowed.

To keep the transmission power at 1Watt level, the To keep the transmission power at 1Watt level, the

communication range should be reduced by about 43.3 times (e.g., 1,000m Æ 23m cell) if the propagation path loss

exponent is 3 5 exponent is 3.5.

Fundamental change is necessary in wireless access

network ÆPresent cellular architecture may not work.

FA/Tohoku University 18

y

FA/Tohoku University 18

M. Hata, “Empirical formula for propagation loss in land mobile radio services”, IEEE Trans. Veh. Technol., VT-29, pp. 317-325, 1980.

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Multi hop Relay Technique

Multi-hop Relay Technique

Promising technique is multihop relay.

Transmit power of mobile terminal, as well as the total

transmit power, can be reduced significantly by applying multi-hop relay technique.

exponent.

loss

path

the

denotes

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3 (

where

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≈

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_h R Single-hop Base station Multi-hop Mobile terminal 1 since hops. of number the denotes where , ) / ( 1 1 < < ⋅ = ⋅ ∝ α − α − α α J P P J J R J R J P total total mh 2008/06/23 FA/Tohoku University 19 1. since 1 < < P J P_mh _h

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Program

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20 August (Wednesday, Katahira Campus)

13:30~14:00 Opening Remarks,p g ,

Fumiyuki Adachi, Tohoku University, Japan

14:00~14:50 "Recent advances in frequency domain equalization",

Prof. David Falconer, Carleton University, Canada

14:50~15:10 Coffee break

15:10~16:00 "Capacity bounds and signaling schemes for bi 15:10~16:00 Capacity bounds and signaling schemes for

bi-directional coded cooperation protocols",

Prof. Vahid Tarokh, Harvard University, USA

16:00~16:50 "Evolving 4G (WIMAX and LTE) to the next level",

Prof. Arogyaswami Paulraj, Stanford University, USA

" d h f d d"

16:50~17:40 "Radio Access Techniques for LTE-Advanced",

Prof. Mamoru Sawahashi, Musashi Institute of Technology, Japan

Technology, Japan

17:40~18:00 Break

18:00~20:00 Welcome Reception

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Program

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21 August (Thursday, Aobayama Campus)

(a part of IEEE VTS APWCS) (a part of IEEE VTS APWCS)

9:15~ 9:25 Opening Session (APWCS)

9:25~10:10 "Review of research and development onp

antennas in Tohoku University",

Prof. Kunio Sawaya, Tohoku University, Japan

10:10~10:30 Coffee break

10:30~11:15 "MIMO signal processing and the impact of

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practical antenna effects",

Prof. Ross Murch, Hong Kong University of Science and Technology China

Science and Technology, China

11:15~12:00 "Lattice reduction based MIMO detection and

its application to multiuser systems",pp y ,

Prof. Jinho Choi, University of Swansea, UK

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Some Concluding Remarks

Next generation wireless networks will require Giga-bit

Next generation wireless networks will require Giga bit

wireless technology of ~1Gbps and >10bps/Hz/BS under severe co-channel interference.

Lots of interesting and important research topics remain

before the born of next generation wireless systems.

Some of the important wireless techniques will be

presented in this GCOE workshop.