building sustainable communities non-directed indoor ......network with a grid of direct fiber...

Kyoto, Japan 22-24 April 2013

ITU Kaleidoscope 2013Building Sustainable Communities

D. R. Kolev1, T. Kubo2, T. Yamada2, N. Yoshimoto2, K. Wakamori11GITS, Waseda University, Japan

2ANSL, NTT Corporation, [email protected]

Non-Directed Indoor Optical Wireless Network with a Grid of Direct Fiber

Coupled Ceiling Transceivers for Wireless EPON Connectivity

Kyoto, Japan, 22-24 April 2013 ITU Kaleidoscope 2013 – Building Sustainable Communities

Outline

Research motivationProposed system

EPON standard Theoretical model Synchronization

Results and discussionConclusion

Directed Hybrid Non-directed

EPON Network


Research Motivation

Goal: high-speed, secure and power efficient indoor communication system for mobile users

DiffusiveLine of sight (LOS)

Indoor optical wireless networks:

Expanding market of portable devices and applications

High capacity mobile access network


Proposed System - EPONNew standards or compatibility with current fiber standards – EPON (802.3ah)Provides seamless connectivity for IP-based communicationsWidely used and cost effectiveScalable bit rates for the users

CMWireless

OLT

Splitter

CM

ONU ONU ONUONU

PON

ONU ONU

OLT

Splitter OLT - optical line terminal

PON – passive optical network

ONU – optical network unit

CM – ceiling module


Proposed system – Theoretical Model1

mbeamcouplingsplittot LLLLL

OAtottAr GLPP

ω=1m,r2=20mm:

Lbeam=45dB

OLT

Splitter

OA PD

Beam spot

Pt

GOA

NASE

Lsplit

Lcoupling

LbeamNAmb

Nth

PArLD Pt

ω- beam waist

r2- Rx aperture diameter

OLT – optical line terminal

OA – optical amplifier

PD –photodiode

LD – laser diode


Proposed system – Theoretical Model2

Eye safety

The transmit power in the wireless part is under 10dBm;

Higher transmit power is possible (diverged beam);

indbnRX

ftotASEOAs

RXOAtotdt

thbnase

RXArd

RkTBBPeBLIGI

GLP

iiiPSNR

424 ,

2,

222

2

inOAubnRX

ftotASEOAs

RXOAtotutu

RkTBBGPeBLIGI

GLPSNR 424 ,

2,

ρRX – PD responsitivity

Is – signal current in the PD

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


Proposed system - Synchronization

arTx1 Tx2

Tx Tx

ra-r

hL1 L2

Synchronization in the fiber part can be achieved by path equalizingIn wireless part the mobile device is mobile with random location – only the biggest delay can be estimated

h=2m, r=1m, Δt=0.64ns


Results – Downlink

0dBm transmit power

Reliable high speed link

Big indoor coverage

10 15 20 25 3010

-20

10-15

10-10

10-5

100

GEDFA, dB

BE

R

100Mbps link with receiver aperture diameter r2=50mm

D=2mD=3m

D=4m

10 15 20 25 3010

-20

10-15

10-10

10-5

100

GEDFA, dBB

ER

100Mbps link with beam spot diameter D=2m

r2=50mmr2=30mm

r2=20mm

PD responsitivity: 0.8A/W

PD load resistor: 50Ω


Results - Uplink

LD with transmit power Pt,d=0dBm

Reliable high speed uplink

Lower speed will further increase the system performance

10 15 20 25 3010

-20

10-15

10-10

10-5

100

GEDFA, dB

BE

R

100Mbps Uplink

r2=120mmD=2m

r2=120mmD=3m

r2=100mmD=2m


Conclusion

Proposed system advantages: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;

Future work:Consideration of GEPON;Better theoretical model and enhanced performance;


Thank you for your attention!

Dimitar R. KolevWaseda University, Japan

[email protected]

building sustainable communities non-directed indoor ......network with a grid of direct fiber...

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