History of the Digital Mobile Radio Systems in NTT & DoCoMo

The University of Electro-Communications

Nobuo Nakajima

2

Progress of the Mobile Radio Systems

3 G

IMT-2000

1979 1992 2001 2010 2020

5G

LTE-advanced?

2 G

Digital

1 G

Analog

3.9 - 4 G

LTE,-advanced

Every 10 years

Access FDMA TDMA CDMA OFDMA, Frequency Scheduling

Frequency 800 MHz 2 GHz 3 GHz > 3 GHzmillimeter wave

Terminal Portable phone Smart phone

3

Access Scheme for 1-4th Generation

FDMA TDMA CDMA

Frequency

Time

Time

Freq

ue

ncy

Frequency Scheduling

TimeFr

equ

ency

Time

Freq

uen

cy

1st Generation

1G Development History

1980 20001990

NTT

‘79 ‘93

PDC(800M)

‘01

IMT-2000

‘94

PDC(1.5G)

‘95

PDC(Half rate)

2.4k

FEC

9.6k

ARQ

28.8k

By 3 time slots

‘97

PDC Packet

i-mode

By PDC-P

‘99

CDMA by DDI

‘98

NTTHigh Capacty

‘86

‘92

NTT DoCoMo

started

‘89

J-TACS by

IDO, Cellular

Analog to Digital

(Replace)

5

1G 2G 3G

384k

- Okumura Hata Curve/Empirical Formula -

Propagation Loss Estimation

Base Station Antenna HeightMobile Station Antenna HeightUrban Area

Distance

Free space loss

Frequency

Pro

pag

atio

n L

oss

PropagationLoss

1G Technologies and Specifications

Frequency

Access Scheme

Applied Technologies

Beginning(1979)

Last Stage(1986)

800 MHz Band

Analog FDMA

Channel Separation 25 kHz 12.5 kHz(Interleaving)

Diversity ReceptionFor BS and MS

Base Station Beam Tilting

AMPS30 kHz

Robust

Interferencereduction

HigherCapacity

(100,000 SubscriberFor Metropolitan Area)

Smaller Cells

Antenna Diversity

Trunk lid Antenna

Roof Top Antenna

In-room Antenna

Sleeve Antenna #1

Sleeve Antenna #2

Trunk lid Diversity Antenna Portable Phone Diversity Antenna

Built-inAntenna

WhipAntenna

9

Interference Reduction by Beam Tilting

Phase

ShifterWithout TiltWith Tilt

ReceivingLevel

Rel

ativ

e R

ecei

vin

g Le

vel (

dB

)

Distance

Without tilt

With tilt

Distance

Tilting Effect

Experimental Result

Antenna

10

Smaller Cells

1979

1995

11

６０００ｃｃ１０ｋｇ

1st Mobie Terminal

Mobile Terminals by NTT

1985 1987

Shoulder Phone(3 kg)

Portable Phone(900 cc, 900 g)

1979

VehicularTerminal(10,000 cc10 kg)

1989

MicrTAC(211 cc)by Motorola

1991

Mova (140 cc)

2nd Generation

14

2nd Generation Digital System

Development in the World

USA:FDMABy Motorola, Lucent

Purpose: High Capacity, Data CommunicationCommon Interface (Europe)

Japan:FDMABy NTT

EuropeGSM (Group Special Mobile)Competition(TDMA, CDMA, Frequency Hopping,,,,,)

3ch TDMA

８ｃｈTDMA

3 InternationalStandards

cdmaOneWas added

Ericsson proposed to TIA

PDC and IS-54(Digital APMS)

Access Scheme

Speech CODEC

PDC IS-54

3ch TDMA

Channel Separation 25 kHz

V-CELP (Motorola)11.2 kbps

PSI-CELP (DoCoMo)5.6 kbps

CELP13 kbps

CountermeasureFor Multipath Fading

30 kHz

Antenna Diversity(Both Direction)

Equalizer

Mobile Terminal Dual ModeSingle Mode

Modulation Pi/4 shift QPSK

Hardware Tech.

Efficient Linear Amp. (MS)

Common Power Amplifier (BS)

16

Time

TDMA Frame

Reason of 3ch TDMA

CONT

- Minimum Time Slot Number -

Transmit Receive Monitor

Measure Receiving Levels from Surrounding Base Stations for MAHO (Mobile Assisted Hand Over)

Minimum Bandwidth for Multipath fading Countermeasure

Pi/4 shift QPSK

Constellation Spectrum

Measured Delay Spread

BasinArea

Urban Area

Delay Spread

Acc

um

ula

tio

n

Feed Forward Ultra Linear Common Power Amplifier (SAFF: Self Adjusting Feed forward)

SAFF

Without SAFF

Pilot Signal

Main AMP

Detect Distortion

Coupler

Controller PilotDetection

SubAMP

Spectrum

Coupler Coupler

30 channels, Total 30 W

From Massive and Lossy Filter Bank

to Common Power Amplifier

Antenna

1G

Filter BankMODEM

Power Amplifier

2GAntenna

MODEM

UltraLinerPowerAmplifier

20

MODEM

Efficient Liner Power Amplifier

For Mobile Terminal

Binary Data

MOD

EnvelopDCAmplifier

F-ClassAmplifier

Power Supply

Power Efficiency : 40 %

2G Development History

1980 20001990

NTT

‘79 ‘93

PDC(800M)

‘01

IMT-2000

‘94

PDC(1.5G)

‘95

PDC(Half rate)

2.4k

FECData Speed： 9.6k

ARQ

28.8k

By 3 time slots

‘97

PDC Packet

i-mode

By PDC-P

‘99

CDMA by DDI

‘98

NTTHigh Capacty

‘86

‘92

NTT DoCoMo

started

‘89

J-TACS by

IDO, Cellular

Analog to Digital

(Replace)

22

1G 2G 3G

384k

Propagation Loss + 6dB

Soft Decision for Error Correction

Propagation Loss versus Frequency

0

10

20

30

-10

-20

-30

100 M 1 G 10 G

Frequency (Hz)

Re

lative

Lo

ss (

dB

)

2G 3G 5G 8G

２G

３G

４G

１G

Pager

3rd Generation

25

USA:Enhancement of cdmaOne

High Speed (2Mbps), New ServicesNationwide Unified Standard

Japan:W-CDMA

EuropeUMTS

cdma2000

W-CDMA

3 InternationalStandard

China:TDD type CDMA

TDS-CDMA

3rd Generation System

Development in the World

Purpose:

W-CDMA versus IS-95

Access Scheme

Spreading Code

W-CDMA (UMTS) IS-95

CDMA

Base StationSynchronization

No By GPS

Bandwidth 5 MHz 1.25 MHz

OrthogonalFor any spreading factor

OrthogonalFor same spreading factor

3rd Generation

EV-DO, HSPA

28

Re

ce

ivin

g L

eve

l (d

B) User A

User B

User C

Round Robin

Maximum CIR

Proportional

Fair

Th

rou

gh

pu

t

HSPA ( High-Speed Packet Access )

Best Effort

14.4 Mbps by 5 MHz Bandwidth !

Channel Assign

3.9 - 4th Generation

Unified International Standard

By 3GPP

LTE versus W-CDMA

LTE W-CDMA

Dominant Access Scheme

Packet Circuit Switch

MaximumTransmission Bitrate

Down: 100 MbpsUp : 50 Mbps

Down: 14 MbpsUp : 7 Mbps

Transmission Delay < 5 msec > 10 msec

Bandwidth 1.4M, 3M, 5M, 10M, 15M, 20M

5M only

Multiplexing OFDM CDMA

Scheduling Every 1 msec No

Antenna MIMO, Diversity Diversity

Review for Technological Improvements

Transmission Bitrate

2.4k

1k

28.8k

384k

3.6M

100M

>=1G

2G 3G 3.9 – 4G 5G

1M

1G

14M

Tra

nsm

issio

n B

itra

te

Guarantee Best Effort

32

Spectrum Efficiency

From National Broadband Plan (FCC）

10kbps 100kbps 1Mbps 10Mbps

Guarantee BEST EFFORT

Transmission bitrate

Spec

tru

m E

ffic

ien

cy

Spectrum Efficiency10

1

0.1

0.01

1k 1M 1G

GPRS

W-CDMA

HSPA

LTE

Transmission Bitrate = Spectrum Efficiency 2

Future

2 times / a year → 256 times at 2020

Novel ideas and technologies are necessary against such

huge traffic demands.

Traffic Explosion

37

Cell Size will be Reduced

200

100

400

1k

4k

10k

0 2 10k 1M 100M 10G

1

2345

Frequency (GHz)

Transmission Bitrate (Hz)

Output 250mWFade Margin 5.3dB

Max

Ran

ge (

m)

2k

40

64k

HSDPA 3.6M

HSDPA 7.2M

100M

1G

1980 2000 2020

Vehicular phone

Portable phone

Smart phone

email

Line

Wearable

voice

Ｍ２Ｍ

Entertainment

ＩｏＴ

Virtual Reality

Future Service and Human Interface

Tele-Existence

38

39

Nobuo Nakajima

Thank you for listening and Congratulationfor Prof. Adachi’s New Life!