ITU Kaleidoscope 2013
Building Sustainable Communities
Non-Directed Indoor Optical Wireless
Network with a Grid of Direct Fiber
Coupled Ceiling Transceivers for
Wireless EPON Connectivity
D. R. Kolev1, T. Kubo2, T. Yamada2, N. Yoshimoto2, K. Wakamori1
1GITS, Waseda University, Japan
2ANSL, NTT Corporation, Japan
dkolev@fuji.waseda.jp
Kyoto, Japan
22-24 April 2013
Outline
 Research
motivation
 Proposed system
EPON standard
 Theoretical model
 Synchronization

 Results
and discussion
 Conclusion and future work
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities
Research Motivation
Expanding market of portable
devices and applications
High capacity mobile
access network
Goal: high-speed, secure and power efficient indoor
communication system for mobile users
Indoor optical wireless networks:
High
Diffusive
speed
Line of
sight (LOS)
High
security
Low power consumption
fiber
CM
CM
OLT
Electromagnetic interference immunity
CM
OLT - optical line terminal
ONU – optical network unit
ONU
ONU
Directed
Hybrid
ONU
CM – ceiling module
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities
Non-directed
Proposed System - EPON
New standards or compatibility with current
fiber standards – EPON (802.3ah)
Provides seamless connectivity for IP-based
communications
Scalable bit rates for the users
Widely used and cost effective
OLT
OLT
Splitter
Splitter
CM
PON
ONU
CM
Wireless
ONU
ONU
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities
ONU
ONU
ONU
Proposed system – Theoretical Model1
Splitter
GOA – Optical gain
Lcoupling
ω - Beam waist
r2- Rx aperture
diameter
Lsplit
Ltot – Total loss
NAmb
Lbeam
Lm – Loss margin
PAr – Received
optical power
OLT
Pt
Beam spot (Gaussian)
GOA
NASE
Nth
Photodiode PAr
Pt Laser diode
Optical amplifier
Ltot  Lsplit LcouplingLbeamLm
PAr  Pt LtotGOA
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities
ω=1m, r2=20mm:
Lbeam=45dB
Proposed system – Theoretical Model2
SNRd 
PAr  RX 2
2
2
iase
 ibn
 ith2
P
ρRX – PD responsitivity

Is – signal current in the PD
t , d LtotGOA  RX 
B
4kTB
4 I s GOA I ASE Ltot
 2e RX Pbn,d B 
 f
Rin
2
P
t ,u LtotGOA  RX 
SNRu 
B
4kTB
4 I s GOA I ASE Ltot
 2e RX Pbn,u BGOA 
 f
Rin
2
IASE – ASE current in the PD
B – bandwidth
Δvf –band pass filter bandwidth
e – elementary charge
Pbn – ambient noise power
Rin – feedback resistance
k – Boltzmann’s constant
T - absolute temperature
Eye safety
The transmit power in the wireless part is under 10dBm;
(Class 1 laser product: IEC 60825-1)
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities
Proposed system - Synchronization
Tx
L1
h
L2
a-r
Tx1
Synchronization
Tx
in the fiber
part can be achieved by path
equalizing
In wireless part the mobile
device is mobile with random
location – only the biggest
delay can be estimated
r
r
a
Tx2
h=2m, r=1m, Δt=0.64ns
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities
Results – Downlink
10
100Mbps link with receiver aperture diameter r2=50mm
0
10
100Mbps link with beam spot diameter D=2m
0
D=4m
10
-5
10
-5
r2=50mm
r2=30mm
10
10
10
D=3m
-10
BER
BER
D=2m
-15
10
-20
10
10
15
20
25
30
10
r2=20mm
-10
-15
-20
10
15
GEDFA, dB
20
25
GEDFA, dB
0dBm transmit power
PD responsitivity: 0.8A/W
Big indoor coverage
PD load resistor: 50Ω
Reliable high speed link (100Mbps)
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities
30
Results - Uplink
10
100Mbps Uplink
0
r2=120mm
D=3m
10
-5
Reliable high speed
uplink (100Mbps)
BER
r2=120mm
10
-10
D=2m
r2=100mm
Lower speed will
further increase the
system performance
D=2m
10
10
-15
-20
10
15
LD with transmit power
Pt,d=0dBm
20
25
GEDFA, dB
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities
30
Conclusion
Proposed
system - Sustainability:
Compatible
with EPON standard;
High-speed communication for mobile users;
Low power consumption compared to RF;
High security;
Free RF spectrum (interference immunity)
– lower human exposure to electromagnetic waves;
- free resources for other applications;
Eye safety regulations considered;
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities
Future work
Proposed
system:
Better
theoretical model;
Enhanced performance:
-Transimpedance amplifier implementation;
-Gigabit links;
Prototype;
Standardization:
Update
of EPON standard for wireless networks;
Propose for change in the uplink wavelength;
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities
Thank you for your attention!
Dimitar R. Kolev
Waseda University, Japan
dkolev@fuji.waseda.jp
Kyoto, Japan, 22-24 April 2013
ITU Kaleidoscope 2013 – Building Sustainable Communities