NetLight Introduction toFSO Tecnology

©Copyright Netronics Inc .

2008

Why Free Space Optics (FSO)?2

FSO Communication is using the LASER light as the carrier.

Full Duplex, Full Speed AND No Delay.

Up to 1 Gbps Ethernet

Distances – up to 5km.

No License is required.

Easy to install and almost no maintenance is required.

I - What is FSO

3 Why Free Space Optics (FSO)?

4 Why Free Space Optics (FSO)?

Only about 10% of commercial buildings are lit with fiber

Wide Area Networks between major cities are extremely fast

• Fiber based• >2.5 Gbps

Local Area Networks in buildings are also fast

• >100Mbps

The connections in between are typically a lot slower

• 0.3-1.5 Mbps

The “Last Mile” Bottleneck Problem

5

Why Free Space Optics?Why Not Just Bury More Fiber?

Cost

Rights of Way

Permits

Trenching

Time

With FSO, especially through the With FSO, especially through the window, no permits, window, no permits, no digging, nono digging, no feesfees

6 Examples of FSO Systems

GroundLasercomTerminal

SatelliteLasercomTerminal

1 Gbps2000 km range

Commercial Lasercom

7

Netronics Communications:More than 7000 links installed

Worldwide Installations

USA Canada Mexico Brazil Argentina Uruguay ChinaSingaporeJapanIndiaPhilippinesTaiwan S. KoreaAustraliaThailandVietnamMalaysiaIndonesia South Africa Nigeria

Slovenia Croatia Latvia Czechoslovakia Gibraltar Luxemburg Netherlands France Norway Greece Germany England Switzerland Sweden Portugal Spain Italy Turkey Israel Saudi Arabia

8 III – The Technology

Sp

rea

d s

pe

ctru

mM

icro

wa

ve

101 102 103 104 105 106 107 108 109 1010 1011 1012 1013 1014 1015 1016

Hertz kHz MHz GHz THz

107 106 105 104 103 102 10 1 0.1 10-2 10-3 10-4 10-5 10-6 10-7 10-8

Frequency

Wavelength

Radio Waves Microwaves Infrared UVPower & Telephone

Co

pp

er

wir

etr

an

smis

sio

n

km meter cm mm mm10-9

nm

1017

Co

axi

al

cab

le

Fib

er

op

tic

AM

ra

dio

FM

ra

dio

La

ser

com

mu

nic

atio

n

Electromagnetic SpectrumUnlicensed

Smaller carrier wavelength / Higher Bandwidth

9 Near Infrared

Visible Spectrum

400 nm 500 nm 600 nm 700 nm 800 nm 900 nm

HeNe 780nm

810nm

850nm

1550nm

Near Infrared

1300nm

10 How does it work?

Network

Fiber Optic Cable

Fiber Optic Cable

Laser Transmitter

Laser Transmitter

ReceiverReceiver

LensLens

Free spaceFree space

Network

11 How FSO works?

2 Transmitter projects the carefully aimed light pulses into the air

5 Reverse direction data transported the same way.

• Full duplex

1 Network traffic converted into pulses of invisible light representing 1’s and 0’s

3 A receiver at the other end of the link collects the light using lenses and/or mirrors

4 Received signal converted back into fiber or copper and connected to the network

Anything that can be done in fiber can be done with FSO

12

IV - Free Space Optics Positioning

High Bandwidth Wireless

Secure Wireless

Short distances

Within Urban areas

Eye safe

13 Bandwidth - Wireless?

What is the fiber technology bandwidth limitation?Unlimited

What is the radio technology bandwidth limitation?Limited (only GHz frequencies)

What is the FSO technology bandwidth limitation?Unlimited

FSO ≡ Ultra Bandwidth Wireless SolutionsNetronics Leading the Gigabit Wireless Revolution

14 Bandwidth - Wireless?

c

10 Gbps

1 Gbps

100 Mbps

10 Mbps

1 Mbps

200 m50 m 500 m 1 km 5 km 15 km+

Fiber

LMDS WiFi

Optical Wireless

T-1DSL

Future Performances

15 Security Wireless?

Is Radio signal secure ? What is the RF signal spectrum ?

Very wide

How many times did you see other Radio network in your area?

FSO ≡ Most Secure Wireless Solutions

Very narrow and directional mrad divergence

Range = R = 1000 m = 1 km

~2 m

Is NetLight FSO signal secure ?

16 Narrow Beam Advantages

Beams only a few meters in diameter at a kilometer

Allows VERY close spacing of links without interference

No side lobes

Highly secure

Efficient use of energy

Ranges of 20m to more than 8km possible

17 Applications

Point-to-Point

Secure Ultra Bandwidth

Wireless Mesh

Ring

18 V - General Terms

Beam Divergence - measure of angle or how much the beam spreads

circle: 360° (degrees) = 2π radians

1 radian = 57° (degrees)

1 milliradian = 0.001 rad = 0.057° (degree)

80 µ radians = 0.00008 rad = 0.0046° (degree) (satellite)

1 radian

Laser Communication System

2.5 mrad divergence

1 mrad divergence

Range = R = 1000 m = 1 km

2.5 m

1 m

80 µrad divergence8 cm

STRV-2 Satellite

Laser Communication System

19

Link stability – Depending on Beam divergence

TxTx

High geometric loss. . . . . .good link stability.

Narrow angle

TxTx

. . .poor link stability.

Wide angle

20 Geometric loss

Beam Area Receiver Lens Area

dB

= divergence angle, dB = R

GM (Geometric Loss) = 10 log (Rx lens Area/Beam Area)

= 10 log [dR /( R )]2

dR

R (air transmission distance)

Tx

21 The Decibel - dB

A logarithmic ratio between two values

In the optical world of Power in mW,

dB=10*Log(power2/power1)

3 dB = ratio of 2/1

6 dB = ratio of 4/1

10 dB = ratio of 10/1

20 dB = ratio of 100/1

50 dB= ratio of 100,000/1

Gain/Loss Multiplier

+30 db

+20 db

+10 db

0 db

-10 db

-20 db

-30 db

1000

100

10

1

.1

.01

.001

22 Link Budget

System GainTransmitter(s) power

Receiver sensitivity

AttenuationGeometrical attenuationAtmospheric attenuation

ScatteringScintillationTurbulence

System factorsComponents and assemblies tolerancesSystem misalignment

Total available margins = System Gain - Attenuation

23 Environmental factors

Building Motion

Alignment

WindowAttenuation

Fog

Each of these factors can “attenuate” (reduce) the signal. However, there are ways to mitigate each environmental factor.

Scintillation

RangeObstructions

Low Clouds

Sunlight

24

Environmental effects – Rain,Scintillation & Haze

Type of events

25 Fade Margin calculationFade Margin Calculation for :

Fade Margin 30.83 db 15.42 db/Km

Enter values from the data sheets for the specefic TereScope

Fill only the white cells

To Calculate Geometric Loss.

1 Calculate the one of the projected pattern : 2 Calculate the area of the receiver on the link head :

distance [m]beam

divergence [mrad]

beam diam. [m]

beam area [cm2]

RX diameter [cm]

No of RXs

RXs total Area [cm2]

2000 2 4.000 125664 22.4 1 394.1

3 Convert the two areas ratio to dB using the 10 log rule :Geometrical loss [db] -25.036

To Calculate Total Link Budget. Calculate the power in dbm

- Transmit Total Power 19.87 dbm power mW dbm

- Receiver sensitivity -45.00 dbm 95 19.78

- Total Available System Gain 64.87 dbm 158.49 22.0

To Calculate Distance Dependant Loss.

- Total Link Length 2000 m@ 0.5 dB/Km -1 db

- Divergence Geometric Loss 2000 m -25.036 db

- Total Link Loss -26.036 db

To Calculate Fixed Loss.

- Equipment Loss (beam loss, mis-alignment, lenses...) -6.00 db

- Scintillation Loss 2000 m@ 1 dB/Km -2 db

- Total Equipment Loss -8.00 db

Total system losses@ 2000 -34.04 db

Calculated Fade Margin @ 2000m 30.83 db 15.42 db/Km

TS5000/155

26

VI – Effects of the weather on FSO com.

Effects of the atmosphere on laser beam propagation

Atmospheric attenuation absorption scattering

Atmospheric turbulence laser beam wander scintillation

27Environmental effects–Scattering,Scintillation & Turbulence

ScatteringMajor Factor – Haze, Fog, Smog

Scintillation Moderate Factor - Air shimmering off hot surfaces

Turbulence / Beam WanderMinor Factor – Different density air layers formed locally by temperature differences

28 Scattering

Typical Scattering Attenuation Factorsfor Various Weather Conditions

29

Effective Link Range vs. Winter Visibility

For laser transmission, attenuation by fog is much greater than attenuation by rain (opposite for microwaves)

Fog droplet size (5 to 15 µm) laser wavelength

Rain droplet size (200 to 2000 µm) microwave wavelength

Effect of snow is between rain and fog

FOGRAINSNOW

30 Scintillation & Turbulence

Atmospheric turbulence (ie. wind) produce temporary pockets of air with different temperature thus different density thus different index of refraction.These air pockets and are continuously being created and then destroyedas they are mixed. The effect of these cells which lie along the laser beam path depends on the size of the cells.

Laser Beam Wander if the cells are larger than the beam diameter

Scintillation if the cells are smaller than the beam diameter. The wavefront becomes distorted due to constructive and destructive interference creating fluctuations in receive power, similar to the twinkling of a distant star.

Transmitter Receiver

Transmitter Receiver

31 Scintillation & TurbulenceP

ower

Time

Po

we

r

Time

Laser Beam WanderTransmit power Receive power

Pow

er

Time

Po

we

r

Time

Scintillation

Total Effect is the sum of both

Po

we

rTime

32

Scintillation caused burst errors

Serial bit stream

Fluctuating received laser power

Minimum receive power threshold

Burst error Burst error

33

Link Bandwidth vs. Link Range @ various Atmospheric attenuation values

**

NetLight G-3500

NetLight 155-5400

Ethernet/4E1

E1

Bandwidth

1 km

1.25Gbps

100Mbps

10Mbps

2Mbps

2 km 3 km 4 km 5 km

*

30 dB/km

17 dB/km

10 dB/km

3 dB/km

@

@

@

* @

For operation under light to medium rain, light snow, light haze.

*

For operation under medium to heavy rain – snow, thin fog.

For operation under cloudburst, medium snow, light fog.

For operation under blizzard, moderate fog.

@

6 km

34 VII - Competitive Technology

Spread Spectrum DisadvantagesSusceptible to RF interference in congested areas

Can be monitored easily

Limited actual bandwidth (throughput of 2-54 Mbps half duplex)

Microwave DisadvantagesCost (the higher the bandwidth, the greater the cost)

Complex installations

Licensing required for higher frequencies

35

VIII - Netronics NetLight™ Series - Matrix

The Most Comprehensive Free Space Optics SolutionsIn The Industry

Distances Short Meduim Long

100Mbps )Fast-Ethernet(

Fast Ethrnet NetLight 100-800

1-155Mbps 155 NetLight 155-1900 NetLight 155-1900 NetLight 155-5400

1.25Gbps)Giga-Ethernet(

Gigabit NetLight G-1000 NetLight G2300 NetLight G-3500

36 IX – TS Installation Examples

NetLight G-3500 Datec

37

NetLight with Fusion

M6- France

DisneyLand - France

38

Sofdit, 7m pole - France

Yanisahra - Turkey

39

40

Vitrolles – France

10 links

41

42

1-155Mbps Interface unit

Air LinkTransmitter

Air LinkReceiver

AC / DCPowerSupply

Clock / Data Recovery

Data Out

Data InInterface

A - BLOCK DIAGRAM

RSM-DC)Option(

ControlPanel

ManagementUnit(optional)

X - NetLight Structure

43

4 E1/T1Multiplexer /

Demultiplexer

DeviceClock/DataRecovery

Air LinkTransmitter

Air LinkReceiver

E1/T1 Line Interface unit

E1/T1 Line Interface unit

E1/T1 Line Interface unit

E1/T1 Line Interface unit

Control Panel

Management Unit (optional)

AC/DCPowerSupply

B - BLOCK DIAGRAM

44

Very high bandwidth (1.5GBps)

License free

Most secure wireless medium

RFI/EMI immunity

No cross-talk or cross interference

Safe, no health hazards

Easy to relocate links

Low maintenance

Fast deployment

Advantages of Infrared Wireless links

XI - Summary

Thank You

©Copyright Netronics Inc .