ITU-T Kaleidoscope Conference
Innovations in NGN
An Alternative Access Technology for
Next Generation Networks based on FullOptical Wireless Communication Links
Mitsuji Matsumoto1, Kamugisha Kazaura1, Pham Dat1,
Alam Shah1, Kazunori Omae1,Toshiji Suzuki1, Kazuhiko Wakamori1,
Takeshi Higashino2, Katsutoshi Tsukamoto2 and Shozo Komaki2
1Global
Information and Telecommunication Institute (GITI),
Waseda University, Saitama, Japan
2Graduate School of Engineering, Osaka University, Osaka, Japan
Geneva, 12-13 May 2008
Contents
Broadband access technologies
Optical wireless technologies
Overview and application areas of OWC
Conventional OWC systems
New F-OWC systems
Advanced DWDM RoF-OWC systems
Experiments results and analysis
Conclusion
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Broadband Access Technologies
Broadband access technologies and other wireless technologies
and standards
10 Gbps
Data rate
1 Gbps
100 Mbps
Visible light
communications
OWC
Systems
F-OWC
system
Optical fiber
communication
MM wave
communication
OpticalUWB
WLAN
10 Mbps IrDA
PAN
WLAN
a/b/g
DSL
WiMAX
Personal area
Communication
1 Mbps
Bluetooth
ZigBee
100 Kbps
1m
10 m
100 m
1 km
10 km
100 km
Communication distance
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Overview of Optical Wireless
Communications
OWC is the transmission of modulated visible or infrared (IR) beams through the
atmosphere to obtain broadband communications.
Advantages
Secure wireless system not easy to
intercept
Easy to deploy, avoid huge costs Cosmic radiation
involved in laying cables
License free
Frequency (Hz)
Possible for communication up to
several kms
Can transmit high data rate
Wavelength (m)
Disadvantages
High dependence on weather
condition (rain, snow, fog, dust
particles etc)
Can not propagate through
obstacles
Susceptible to atmospheric effects
(atmospheric fluctuations)
Visible light
T radiation
V radiation
IR radiation
X ray radiation
1020
Communications radiation
Microwave, radar
1018
1016
1014
250 THz
1012
TV
VHF
1010
(1 THz)
108
(1 nm)
(1 μm)
(1 mm)
(1 m)
10-12
10-9
10-6
10-3
100
0.4
0.5
0.6
0.7
670
(1 MHz)
(100 m)
102
λ = wavelength
f = frequency
OWC
Visible
light
106
(1 GHz)
(1 pm)
C0 = 300 000 km/s
C=λxf
SW
Fiber transmission
wavelength range
0.8
780 850
0.9
1.0
1.1
1.2
1.3 1.4
1300
1.5
1.6
μm
1550 1625 nm
Electromagnetic spectrum
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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OWC technology application scenarios
Terrestrial
Metro network extension
Last mile access
Enterprise connectivity
Fiber backup
Transmission of
heterogeneous wireless
services
Mountainous terrain
Internet
Metro network
extension
OWC transceiver and
remote base station
Backhaul
(~5 km)
Areas with no
fiber connectivity
OWC link
Optical fiber link
RF based links
OWC transceiver
Remote located
settlements
Data relay satellite
Space
Inter-satellite
communication (cross link)
Satellite to ground data
transmission (down link)
Deep space communication
Inter-satellite link
Space station
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
Demonstration of
2.5 Gbps link
Fiber optic link
High-speed (10Gbs)
optical feeder link
Ground station
with adaptive optics
5
OWC technology
Optical fiber
Electrical
signal
Conventional OWC system
OWC
antenna
Optical source
module
OWC channel
O/E and E/O
conversion module
(a) Conventional OWC system
Direct coupling of free-space
beam to optical fiber
Optical fiber
F-OWC
antenna
WDM OWC channel
(b) New F-OWC system
Direct connection between
RoF and F-OWC
F-OWC
antenna
Operate near the 800nm wavelength
band
Uses O/E & E/O conversion
Data rates up to 2.5 Gbps
Bandwidth and power limitations
New F-OWC system
Uses 1550nm wavelength
Seamless connection of optical
wireless beam and fiber.
Multi gigabit per second data rates
(using optical fiber technology)
Compatible with existing fiber
infrastructure
Protocol and data rate independent
Cellular
DVB
Advanced DWDM RoF-OWC system
Uses 1550nm wavelength
Transport multiple RF signals using
WiFi
DWDM OWC channels
RoF
RoF
Realize heterogeneous wireless
DWDM RoF-OWC
WiMAX
channel
Heterogeneous
services e.g. WLAN, Cellular,
wireless
terrestrial digital TV etc
service signals (c) Advanced DWDM RoF-OWC system
Geneva, 12-13 May 2008
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First ITU-T Kaleidoscope Conference – Innovations in NGN
Deployment environment
characteristics
Atmospheric turbulence has a significant impact on the quality of
the optical wireless beam propagating through the atmosphere.
Transmit
power
Time
Time
Received
power
Beam wander
Scintillation (Intensity fluctuations )
Time
Time
Combined
effect
Time
Reduces the optical beam power at the
receiver point and causes burst errors
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
Other effects include
Beam broadening and
Angle-of-arrival
fluctuations
Mitigation techniques
include:
Aperture averaging
Diversity techniques
Adaptive optics
Coding techniques
7
Experiment devices and setup
beacon beam
output windows
Bldg. 14 Waseda University
Nishi Waseda Campus
primary mirror
collimation mirror
QAPD/QPD
40mm
1 km
Bldg. 55 Waseda University
Okubo Campus
secondary
fiber connection
FPM
port
mirror
(a) Optical antenna internal structure
Weather measurement
device
Bldg. 14 Nishi
Waseda campus
(b) Experiment field
Optical clock/data
receiver & transmitter
Weather
data recording PC
Power meter
Fiber
amplifier
RF-FSO
antenna
F-OWC
antenna
Atmospheric effects
measurement antenna
BERT
Scintillation data
recording PC
CCD
monitor
Remote adjustment
& monitor PC
Geneva, 12-13(c)
MayRooftop
2008 setup
(d) Experimental hardware setup
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Experimental results and analysis
Specifications of equipment
used in experiment
Parameter Specification
Value
Data rate (Gbits/s)
2.5 & 10
E/O (directly mod. DFB laser)
OOK/NRZ
Test data pattern
223-1 &
Boost EDFA output (mW)
Receiver opt. filter 0.5dB BW
Antenna aperture (mm)
Rec. sensitivity (BER = 10-12)
27-1 PRBS
100
±11 nm
40
-30 dBm
Experiments
F-OWC system performance evaluation experimental setup
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
BER and received power
characteristics
WDM transmission
characteristics
Application data
performance characteristics
9
Experimental results and analysis cont.
BER and receiver power characteristics
10
10
-4
-6
-8
-10
60
0
10
50
-10
10
40
-20
10
30
-30
20
10
Error free
10
-12
0:00
3:00
6:00
9:00
12:00
Time
15:00
18:00
21:00
0
24:00
10
10
10
0
-2
Bit error rate
Received power (dBm)
Temperature (ο C)
Visibility (km)
Date: 26 ~ 27 January 2006
Temperature (ο C)/Visibility (km)
10
Date: 30 October 2005
Log(BER)
Log(BER)
10
-2
Bit error rate
Received power (dBm)
Temperature (ο C)
Visibility (km)
Received power (dBm)
10
0
Temperature (ο C)/Visibility (km)
10
10 Gbps transmission
-4
-6
-8
-10
60
0
50
-10
40
-20
30
-30
20
10
Error free
Single channel 1550 nm data
link operating at 2.5 Gbps
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
-12
10
18:00
20:00
22:00
24:00
Time
02:00
04:00
0
06:00
Received power (dBm)
2.5 Gbps transmission
Single channel 1550 nm data
link operating at 10 Gbps
10
Experimental results and analysis cont.
Eye pattern characteristics
Effect of strong
atmospheric turbulence
2.5Gbps
transmission
After transmission (typical case)
After transmission (worst case)
10 Gbps
transmission
Before transmission
After transmission
Most of the key wave shape parameters
are within acceptable tolerance
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Experimental results and analysis cont.
WDM experiment
Four channel 1550 nm data link operating at 2.5 Gbps WDM
WDM received signal spectrum
BER and received power characteristics
10
0
ITU Grid 100GHz spacing
0
Date: 23 ~ 24 November 2005
1549.3 1550.1 1550.9 1551.7
nm
nm
nm
nm
Log(BER)
10
10
10
10
-2
-10
-4
-20
-6
-30
-8
-10
(Error free)
-12
10
18:00
-40
1550.1 nm BER
1550.9 nm BER
Received power
Received Power (dBm)
10
-50
21:00
24:00
-60
03:00
Time
ƒ
ƒ
2.5 Gbps X 4 channels with output power 100mW/wavelength
Stable communication was achieved with no fluctuation or
interference between wavelengths
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Conclusion
Developed a transparent optical wireless
communication system which is readily compatible
with existing widely deployed PON access technology.
Demonstrated that the systems offers stable and
reliable transmission at single channel 2.5 and 10
Gbps as well as WDM transmission.
Confirmed the technology can be used as alternative
broadband access technology in the emerging NGN.
Standardization activities with respect to transceivers
and devices for ease in adaptability with existing
broadband access technologies both wire-line and
wireless based.
Further work in research and development of
advanced DWDM RoF-OWC system for heterogeneous
wireless communication signals transmission.
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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ITU-T Kaleidoscope Conference
Innovations in NGN
Supported by
This work is supported by a grant from
the National Institute of Information
and Communication (NICT) of Japan
Thank you for your attention
Kamugisha KAZAURA
(カムギシャ カザウラ)
kazaura@toki.waseda.jp
Geneva, 12-13 May 2008
Backup slides
Geneva, 12-13 May 2008
Experimental results and analysis cont.
BER and receiver power characteristics
10
-6
-8
-10
0
10
50
-10
10
40
-20
10
30
-30
20
10
Error free
-12
10
0:00
3:00
6:00
9:00
12:00
Time
15:00
18:00
21:00
0
24:00
10
10
10
0
Date: 14 January 2006
-2
-4
-6
-8
-10
Bit error rate
Received power (dBm)
Temperature (ο C)
Visibility (km)
Precipitation (mm/hr)
rain rate
~7 mm/hr
rain rate
~4 mm/hr
60
0
50
-10
40
-20
30
-30
20
10
Error free
10
-12
0:00
3:00
6:00
9:00
12:00
Time
15:00
18:00
21:00
0
24:00
Received power (dBm)
10
-4
60
Temperature (οC)/Visibility (km)
Rain rate (mm/hr)
10
-2
Date: 12 January 2006
Log(BER)
Log(BER)
10
Bit error rate
Received power (dBm)
Temperature (οC)
Visibility (km)
Received power (dBm)
10
0
Temperature (οC)/Visibility (km)
10
Single channel 1550 nm data link operating at 2.5 Gbps BER
and received power characteristics under the influence of
strong atmospheric turbulence and rain
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Experimental results and analysis cont.
BER and receiver power characteristics
10
-10
10
30
-20
10
20
-30
-6
-8
-10
10
0
Error free
10
-12
0:00
3:00
6:00
9:00
12:00
Time
Date: 22 January 2006
15:00
18:00
21:00
-10
24:00
10
10
10
-2
-4
Bit error rate
Received power (dBm)
Temperature (οC)
Visibility (km)
Precipitation (mm/hr)
-6
-8
-10
50
0
40
-10
30
-20
20
-30
10
0
Error free
10
-12
0:00
3:00
6:00
9:00
12:00
Time
15:00
18:00
21:00
-10
24:00
Received power (dBm)
10
40
0
Temperature (οC)/Visibility (km)
Rain rate (mm/hr)
10
-4
10
Log(BER)
Log(BER)
10
0
Date: 21 January 2006
Bit error rate
Received power (dBm)
Temperature (οC)
Visibility (km)
Precipitation (mm/hr)
-2
50
Received power (dBm)
10
0
Temperature (οC)/Visibility (km)
Rain rate (mm/hr)
10
Single channel 1550 nm data link operating at 2.5 Gbps BER
and received power characteristics under snow event
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Fluctuation suppression
Monitor output (V)
10
10
10
10
1
Tracking OFF
0
-25
-30
-1
-37
-2
0
1000
2000
3000
Received power (dBm)
Fiber received power after setting the
antenna FPM tracking speed to 1 kHz
Fiber coupled signal
power without FPM
tracking
Monitor output (V)
10
10
10
10
1
-25
-30
0
-1
-2
0
-37
Tracking ON
1000
2000
3000
Received power (dBm)
Time (msec)
Fiber coupled signal
with FPM tracking
Time (msec)
Tracking system reduces the pointing errors which
suppresses the atmospheric induced scintillation effects.
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First ITU-T Kaleidoscope Conference – Innovations in NGN
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Receiving Structure
1. Almost no effect AoA to PD in Existing system
Photo Diode，etc.
Ip1 = Ip2
500μm
2. Necessity to input the Receiving Opt. beam to the core
of the 10μm in diameter SMF
SMF
Po1 ＞ Po2
10μm
Susceptible to atmospheric effects (atmospheric
fluctuations)
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Scintillation (intensity fluctuations)
2
10
1
10
4
１ｋHz
3
2.5
2
FFT
1.5
Relative Power
Relative received power
3.5
0
10
-1
10
-2
1
10
0.5
0
-3
0
1000
2000
3000
10
Time (msec)
Optical beam intensity
fluctuation
1
10
2
3
10
10
4
10
Frequency (Hz)
Frequency response of received
power variations
A general fluctuation rate of variability is distributed within the range
from several to 1kHz.
An quick change of 100Hz or more of received power decreases
dramatically. However, the fiber direct coupling cannot be done
without repairing of the fluctuation
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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Optical outline
beacon beam
output windows
primary mirror
collimation mirror
SIgnal
QAPD/QPD λ=1550nm
Main Signal
λ=1550nm
粗追尾機構
primary mirror
CCD
Beacon
λ=980
Beacon
λ=980
SM-Fiber
secondary
mirror
collimation
mirror
fiber connection port
SM-Fiber
secondary
mirror
FPM□2mm
FPM
Rough Tracking system
Optical
Antenna
QD
Control
Operation
circuit
Optical antenna internal structure
Geneva, 12-13 May 2008
First ITU-T Kaleidoscope Conference – Innovations in NGN
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