R&D activities of radio-over-fiber technology in NICT Presented by Toshiaki Kuri

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R&D activities of
radio-over-fiber technology
in NICT
Toshiaki Kuri
National Institute of Information and
Communications Technology (NICT)
IMT-2020/5G Workshop and Demo Day (Geneva, Switzerland, July 11, 2017)

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Acknowledgement
I would like to thank
Dr. Atsushi Kanno (NICT),
Dr. Pham Tien Dat (NICT),
Dr. Naokatsu Yamamoto (NICT),
Dr. Toshimasa Umezawa (NICT), and
Prof. Tetsuya Kawanishi (Waseda Univ./NICT).
Some resultants of the “Research and Development to Expand Radio
Frequency Resources” project supported by the Ministry of Internal Affairs
and Communications (MIC), Japan are included in this presentation.

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Outline
1. What is Radio-over-Fiber (RoF)
2. R&D Examples of RoF technologies
3. Standardization activities of RoF
technologies at ITU-T SG15
4. Summary

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Applications of RoF technologies
What is radio-over-fiber (RoF) ?
[Ref.] A. Kanno, T. Kuri, and T. Kawanishi, “Radio wave transmission via an optical link,” NICT NEWS, no.432, pp.5-6, Sept. 2013.
(http://nict.go.jp/en/data/nict-news/NICT_NEWS_1309_E.pdf) [Figure is modified.]

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What is radio-over-fiber (RoF) ?
• Two features
Ø Preservation of waveform
Ø Tolerance to electro-magnetic interference
Features of RoF technologies
RF signal source
RF signal RF signalLightwave modulated by RF signal
the same waveform
No interference from radio signal
outside of fiber
E/O conversion
Optical fiber
O/E conversion
RF: radio frequency
E/O: electrical-to-optical
O/E: optical-to-electrical
[Ref.] ITU-T G-series Recommendations – Supplement 55 (07/2015), Radio-over-fibre (RoF) technologies and their applications
(http://www.itu.int/rec/T-REC-G.Sup55-201507-I).
Applicable to
IMT-2020/5G
systems

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LTE VSG
Measuredopticalpower[dBm]
LTE SARoF Tx
OLT
E/O converter O/E converter
ODN
No reach extender
(No optical amplifier)
SNI S/R R/S UNI
ONU
25+5+10 km
3 cascaded
SMFs
20
10
0
-10
-20
-30
-40
0 dB
10 dB
20dB
30 dB
Auto-current
control
Splitting loss
emulation
LTE band #7 EVM
measurement
0-30 dB BW: 1 nm
λc: 1549.5 nm
BW: ≤3 GHz
fRF: 2.68 GHz
BW: 20 MHz
RoF RxVOA EDFA OBPF
BW: ≤3 GHz
R&D examples
RoF transmission of an LTE signal over
a typical optical distribution network (ODN) used in PON systems
[Ref.] ITU-T G-series Recommendations – Supplement 55 (07/2015), Radio-over-fibre (RoF) technologies and their applications
(http://www.itu.int/rec/T-REC-G.Sup55-201507-I).
Strong
candidate of
front-haul
technologies
Radio signal
generator
Remote radio
head
Interconnection with RoF technology

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defined in the
ITU-T G-series
Recs. of PON
systems
EVM[%rms]
Optical path loss [dB]
Required EVM for 64QAM (8 [%rms])
Required EVM for 16QAM (12.5 [%rms])
20-MHz bandwidth QPSK
20-MHz bandwidth 16QAM
20-MHz bandwidth 64QAM
After 40-km SMF
ODN
classes
N1 class
N2 class
E1 class
E2 class
80
70
60
50
40
30
20
10
0
0 10 20 30 40 50 60
Required EVM for QPSK (17.5 [%rms])
EVM for back-to-back: < 1
[Ref.] ITU-T G-series Recommendations – Supplement 55 (07/2015), Radio-over-fibre (RoF) technologies and their applications
(http://www.itu.int/rec/T-REC-G.Sup55-201507-I).
R&D examples
Measured EVM (transmission quality)
Also useful for
microwave-band
IMT-2020/5G
systems

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R&D examples
DSP-assisted analog RoF technologies (100-GHz-band)
≥ 40 Gbit/s
Radio receiver
with digital signal processing
Optical frequency
~ 100GHz
16-QAM signal
Optical technology Digital signal
High-speed digital
signal processing
RoF technology
Millimeter-wave-band
radio signal(s)
[Ref.] A. Kanno, T. Kuri, and T. Kawanishi, “Radio wave transmission via an optical link,” NICT NEWS, no.432, pp.5-6, Sept. 2013.
(http://nict.go.jp/en/data/nict-news/NICT_NEWS_1309_E.pdf) [Figure is modified.]
Optical
multi-level
modulator
Direct optical-
to-millimeter-
wave converter
Millimeter-wave
signal generator
w/ optical technol.

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R&D examples
10 Gbaud
V-pol. H-pol.
20 Gbaud
Receiver
Transceiver
Optical fiber
RF shield room
90-GHz wireless link
20-Gbaud QPSK
RoF signal generator
RoF transmission experiment in shield room
Useful for future
millimeter-
wave-band and
high-bit-rate
5G/B5G systems

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Macro-cell Small-cell
●High data rate : > 10 Gbps ●High capacity ●Low latency ●Low cost
BBUs
Fibers
BBU
RRH
Fiber
R&D examples
Advanced wireless network for IMT-2020/5G systems
●High O/E efficiency
●High output power
Our developed key component for O/E conversion
Over 100GHz
responsivity with no bias
[Ref.] T. Umezawa, K. Kashima, A. Kanno, A. Matsumoto, K. Akahane, N. Yamamoto, and T. Kawanishi “100-GHz Fiber-Fed Optical-to-Radio
Converter for Radio- and Power-Over-Fiber Transmission,” IEEE J. Selected Topics in Quantum Elec., vol.23, no.3, May/June 2017.

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Foreign object debris (FOD) detection system by using millimeter-wave-band frequency-modulated
continuous-wave (FM-CW) signal
Millimeter-wave-band
FM-CW signal
Optical distribution network
Debris (FOD) Alert
High-precision imaging technology using 90-GHz-band linear cells
(Collaborative R&D project: FY2011- FY2015)
R&D examples
RoF technology

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Standardization activities at ITU-T SG15
ITU-T G-series Recommendations – Supplement 55 (07/2015)
Radio-over-fibre (RoF) technologies and their applications
Table of contents
1. Scope
2. References
3. Definitions
4. Abbreviations and acronyms
5. General concept
6. System architectures
7. Fundamental technologies
8. Network models
9. System design for supporting radio access system over
optical access network
Bibliography
[Ref.] ITU-T G-series Recommendations – Supplement 55 (07/2015), Radio-over-fibre (RoF) technologies and their applications
(http://www.itu.int/rec/T-REC-G.Sup55-201507-I).

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Standardization activities at ITU-T SG15
Draft ITU-T G-series Recommendations
Radio over fiber systems（G.RoF）（from July 2015）
l Abstract（from draft version.0.6 (June 27, 2017)）
This recommendation specifies radio over fiber transmission systems suitable for access
network applications.
l Scope（from draft version.0.6）
This recommendation develops a new type of optical access network based on radio-over-fiber
(RoF) technologies. In general, RoF technologies can be classified into two groups, analog RoF
and digital RoF. The digital RoF requirements may be satisfied by elements of the G.989 series
with necessary enhancements. The analog RoF system is currently unspecified in any other
recommendation. The recommendation will include consideration of the common applications,
the requirements that stem from these, the specification of the analog optical link and/or the
necessary functions to digitally carry the radio signals over various optical access systems, the
associated signal processing, and the management aspects of the systems.
l Co-editors (Q2/15: SG15 Question 2 “optical systems for fibre access network”)
Seung-Hyun CHO (ETRI), Toshiaki KURI (NICT), Yuanqiu LUO (Futurewei Tech. Inc.)
[Ref.] ITU-T SG15 (http://www.itu.int/ITU-T/workprog/wp_item.aspx?isn=10590)

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Summary
R&D activities of RoF technologies in NICT
• Overview of RoF technologies
• Introduction of some R&D examples
ü RoF transmission of LTE signal over PON ODN
ü RoF transmission of W-band signal
ü Communication system application
ü FM-CW radar system application
• Introduction of standardization activities at ITU-T SG15
ü G Suppl.55 “RoF technologies and their applications”
ü G.RoF “RoF systems”