5G Transport and Broadband Access Networks: The … · 5G Transport and Broadband Access Networks: The Need for New Technologies and Standards ... Analog radio over fiber systems-1

ITU Kaleidoscope 2015Trust in the Information Society

5G Transport and Broadband Access Networks: The Need for

New Technologies and Standards

Pham Tien Dat1, Atsushi Kanno1, NaokatsuYamamoto1, and Tetsuya Kawanishi1,2

1National Institute of Information and Communication Technology (NICT), Japan

2Waseda University, Tokyo, Japan

1

Outline

• Motivations

• 5G transport challenges

• Proposed technologies:

– Analog radio over fiber (ARoF)

– Intermediate frequency over fiber (IFoF)

– Radio on radio (RoR)

– Seamless convergence of fiber and millimeter-wave

• Standardization activities

• Conclusion and outlook

Barcelona, Spain, 9-11 December 2015ITU Kaleidoscope 2015 - Trust in the Information Society

2

Motivations


3

Higher system capacity

. 1000x capacity/km2

Massive device connectivity

. 100x connected devices (Even in crowded areas)

Higher data rate

. 100x typical data rate (Even for high mobility)

Energy saving & cost reduction

. Energy saving for NW & terminals

. Reduced NW cost incl. backhaul

Reduced Latency

. RAN latency: < 1ms

5G

5G mobile networks ITU Connect 2020

• ICTs: key enabler for social, and sustainable growth.

• 2020: 90% broadband coverage for rural worldwide

Needs for new transport technologies and standards

Source: NTT Docomo While paper 2014

5G transport network challenges


4

delay, reliability

bit-rate,delay

Accessibility, dense crowds

simple devices,coverage

Accessibility, mobility

Amazing speed

Great service in a

crowd

Ubiquitous things

communicating

Super real-time and reliable

connections

Best experience follows you

• Transport: different requirements, low cost, simple, high data rate, flexible

Analog radio over fiber systems-1

• Very high data rate; long latency; synchronization and jitter problems; high–speed D/A and A/D (high cost).


IQ: In-phase/Quadrature

IQ Mod: IQ modulation

D/A: Digital to Analog

BB to RF: Baseband to Radio Frequency

Tx/Rx: Transmitter/Receiver

Optical Tx

(Digital)

Center Remote

IQ signals

IQ ModOptical Rx

(Digital)D/A BB to RF

Optical Tx

(Analog)

Center Remote

IQ

signalsOptical Rx

(Analog)IQ ModD/A

• Low bandwidth; low latency; no synchronization and jitter; co-transmission; better co-operation.

5

Digitized transmission

Analog transmission

Analog radio over fiber systems-2

• Satisfactory performance; degradation at high fre.

• Further studies: improvement methods


-2 0 2 4 6 8 10 12-44

-40

-36

-32

-28

RF Tx. Power (dBm)

EV

M (

dB

)

Carrier fre. at 5 GHz

Carrier fre. at 10 Ghz

Carrier fre. at 15 GHz

-15 -10 -5 0 5 10 150

2

4

6

8

10

Tx. RF. Power (dBm)E

VM

(%

)

Carrier at 2 GHz

Carrier at 6 GHz

Carrier at 12 GHz

6

WLAN 802.11 ac signal LTE-A signal

EVM: Error Vector Magnitude

Required Required

• Low spectral efficiency, high cost

HS-

PD

MMW

PD

PDPD

• High spectral efficiency, low cost, matured technology


Intermediate frequency over fiber-1

7

Radio over fiber

Intermediate frequency over fiber

PD: Photodiode; MMW: Millimeter-wave

Intermediate frequency over fiber-2

• Satisfactory performance, low fiber dispersion

• Other issues: LO signal delivery; improved methods


Mod.

Amplifier

LDCentre

Attenuator

Mod.

12 GHz

Laser

LTE-A

Laser

PD

Remote

Down.

X4

PD

-19 -17 -15 -13 -11 -9 -72

4

6

8

10

Rx. Opt. Power (dBm)

EV

M (

%)

20-m SMF

20-km SMF

40-km SMF

8

Experiment setup LTE-A signal

Mod: Modulator; PD: Photodiode

Amplifier

Local

Oscillator

Filter

Filter

Attenuator

Mixer

Amplifier

LTE-A

Required

Down: down-converter

Radio on radio-1


9

Millimeter-wave and terahertz wave:

• Digitized transmission: high data

rate, high cost

• Analog transmission (Radio on

Radio): low required data rate,

cost effective

LTE-A

96 GHz

Local Oscillator

Center

Amplifier

Down.

Remote

Amplifier Amplifier

LTE-A

3 m

Radio on radio-2

• Satisfied performance, MMW link up to 1.5 km

• Some signal degradation because of distortions

• Issues: compensation methods, device integration, standardizations

(b)


-35 -30 -25 -20 -15 -102

3

4

5

6

7

8

Tx. RF. Power (dBm)

EV

M (

%)

QPSK signal

16-QAM signal

64-QAM signal

-21 -19 -17 -15 -13 -112

3

4

5

6

7

8

9

Tx. MMW. Power (dBm)

QPSK signal

16-QAM signal

64-QAM signal

10

Received LTE-A Vs Tx. Power (LTE-A) Vs Tx. Power (MMW)

EVM: Error Vector Magnitude

Required Required

Convergence of fiber and radio-1

×

High-speed radio

Optical fiber


• Protection link against fiber being cut at disaster

• Temporal link to at disaster recovery

• “Last mile” solution until optical fiber deployment

11


• Simple, low latency, low power consumption, simpleoperation and management


Radio access unit

Optical

Tx

O/E

con

v.

DS

P

Opt. sig. Radio

FE

Large latencyLarge power consumption

RoF-based convergence

Conventional system

Opt. Sig.E/O

conv.

DS

P

Radio

FE

Optical

Rx

Optical

Tx RoF sig.

Radio

FE

RoF sig.E/O

conv.

Radio

FE

Optical

coherent

Rx

O/E

conv.

12

Opt. LO

Local

OscillatorLocal

Oscillator


• High performance, possible high-capacity trans. Issues: high-speed real-time, standardizations


-10 -5 0 5 10 152

4

6

8

10

Tx. RF. Power (dBm)

EV

M (

%)

16-QAM, 30-km SMF

64-QAM, 30-km SMF

16-QAM, 50-km SMF

64-QAM, 50-km SMF

LTE-A

Mod.DE

MU

X

Two-tone

Gen.

Amplifier PD

Down.

Center

Remote Access

Remote cells

13

Amplifier

20 km

92.5 GHz3m

Amplifier

LTE-A

Experiment setup LTE-A signal performance

PD: Photodiode

Two-tone Gen.: Optical two tone signal generator

Required

Standardization activities

Activities:

• ITU-T SG15 Q2: Passive Optical Network with RoF

Publication: ITU-T G.Suppl.55 “Radio-over-fiber (RoF) technologies and their applications”

• ASTAP EG-SACS: RoF systems for Asian pacific countries

• IEC TC103: Precise measurement techniques for RoFcomponents

• IEEE802: .15.3d, .15 IG THz

Possible issues in standardization:

• Interfaces between RoF and digital networks

• RoF network architecture, and requirements

• Control of cells and networks

• Measurement techniques for RoF components


14

Conclusions

• 5G and broadband access networks poses many challenges to the transport networks.

• The need for a variety of technologies and standards to serve different use cases

• Proposed technologies for flexible, cost effective solutions:

– Analog radio over fiber

– Intermediate frequency over fiber

– Radio on Radio (RoR)

– Seamless convergence of fiber and radio

Other issues:

• Convergence of fixed and mobile networks

• Co-design, co-operation/optimization of optical and radio

• Standardization activities


15

Acknowledgement

This work was conducted as a part of the “Research anddevelopment for expansion of radio wave resources," supportedby the Ministry of Internal Affairs and Communications (MIC),Japan.

Thank you for your attention!

[email protected]


16

mailto:[email protected]

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5G Transport and Broadband Access Networks: The … · 5G Transport and Broadband Access Networks: The Need for New Technologies and Standards ... Analog radio over fiber systems-1