Agenda

1. QUIZ 2. HOMEWORK LAST CLASS 3. HOMEWORK NEXT CLASS 4. FREQUENCIES & PHYSICAL LAYER 5. NOISE 6. TRANSISSION LINES 7. FIBER 8. MICROWAVE 9. SATELLITES & EXAMPLES

INTELSATINMARSAT

Homework

Chapter 7: 5, 6, 8, 11, 12, 16, 19, 23, 81, 85

Note: Since the substitute lecturer covered Juniper ratherthan the class viewgraphs, I’ll cover multiplexing(in syllabus as Session 4) and Error Detection (insyllabus as Session 5) next week.

Homework Chap 2

12. For n devices in a network, what is the number of cable links required for a mesh,ring, bus and star topology?

Mesh: n(n - 1)/2Star: nRing: n - 1Bus: One backbone and n drop lines.

Physical Layer

Figure 7-2

Classes of Transmission Media

Figure 7-3

Categories of Guided Media

UTP

Figure 7-4

Frequency Range for Twisted-Pair Cable

Limitation is distance. Why?

Transmission Lines

We understand transmission lines by oversimplifying them:a. Lump all resistances into a single large resistance. What is R?b. Lump all inductances into a single large inductance. What is L?c. Lump all capacitances into a single large capacitance. What is C?d. Lump all conductance (leakage) into a single large conductance.e. Assume perfectly uniform construction and perfect symmetry so it looks exactly the same from both ends.f. Lump all of the above into a simple impedance network and assume stability. What is Zo?

Transmission Lines

. Transmission Line Impedance:

Zo = LC = Induc ce

Capaci ce

tan

tan =E

Ii

i = IncidentVoltage

IncidentCurrent

Transmission Lines

Impedance mismatches (impedance of load does not equalimpedance of the line) result in a standing wave ratio (how muchenergy is reflected back to the transmitter).

Transmission Line Standing Wave Ratio:

SWR = E

Emax

min = I

Imax

min = Z

Zmax

min

Figure 7-5

Twisted-Pair Cable

Figure 7-6

Effect of Noise on Parallel Lines

Figure 7-7

Effect of Noise on Twisted-Pair Lines

Figure 7-8

Cable with Five UnshieldedTwisted Pairs of Wires

Figure 7-9

UTP Connection

Figure 7-10

Shielded Twisted-Pair Cable

Helps eliminate cross-talk. What is cross-talk?

• Category 1. The basic twisted-pair cabling used in telephone system. OK for voice & low speed data.

• Category 2. Next higher grade. Generally good for voice & data up to 4 Mbps.

• Category 3. Required to have at least 3 twists per foot and can be used for data transmission up to 10 Mbps. Standard for most telephone systems.

• Category 4. At least 3 twists per foot & other conditioning to bring transmission rate up to 16 Mbps.

• Category 5. Used for data transmission up to 100 Mbps.

EIA Categories of UTP

Figure 7-11

Frequency Range of Coaxial Cable

Why this lower limit?

Figure 7-12

Coaxial Cable

RG 8, 9 & ll. Used in thick EthernetRG 58. Used in thin EthernetRG 59. Used for TV

Transmission Line Connector Distortion

(Why you need BNC or a good screw)

Normal Power Level: - 120 dBmProblem Power Level +/- 10 dB

Linear Non-Linear

Fiber Optic Cable

Figure 7-13

Refraction

Figure 7-14

Critical Angle

Figure 7-15

Reflection

Figure 7-16

Propagation Modes

Figure 7-19

Single-Mode Fiber

Figure 7-20

Fiber Construction

Fiber Optics

Attenuation: Light loss due to both scattering and absorption.

Absorption: The amount of light loss due to its conversion to heat.

Scattering: The disappearance of light due to its leaving the core of of a fiber.

Chromatic dispersion: The tendency of a fiber to cause slightly differing wavelengths of emitted light to travel through the fiber at different speeds.

(See Handout)

Fiber Optics--Markets

Type Environment Type Fiber Common ProblemEnterprise Building or campus Multi-mode Dirty patch cordNetwork Corroded Connector

Cable New Installation Single-mode Certification ofContractor Multi-mode Installation

Long haul Underground/sea Single-mode Breaks & splices Providers Conduit

Optical Power Budget

0 -5-10-15-20-25-30-35

LaunchPower

Launch Temp Coupling Aging Path Fiber Temp Coupling Repair, SrvcePower to Fiber Loss Loss Effect to Rx Safety Margin

+2dB +2dB -3dB -3dB -2dB -4dB/k +1dB +1dB -3dB

By this point you could be downto minus 20 dB

By this point you could be downto minus 30 dB

Source variables Connector & cable variables

Surface Emitting LEDs, Edge Emitting LEDs & Lasers

Attenuation Without Chromatic DispersionWavelength in micrometers .85 1.3 1.55Attenuation -limited MMF MMF SMF MMF SMFspan, km SLED 12 30 22 37 30

ELED 14 37 49 46 70Laser 20 54 104 69 153

Attenuation With Chromatic DispersionWavelength in micrometers .85 1.3 1.55Attenuation -limited MMF MMF SMF MMF SMFspan, km SLED 3 24 19 5 4

ELED 5 34 48 9 8Laser 20 50 104 57 138

Figure 7-21

Radio Communication Band

Figure 7-22

Types of Propagation

Figure 7-23

Frequency Range for VLF

Figure 7-24

Frequency Range for LF

Figure 7-25

Frequency Range for MF

Figure 7-26

Frequency Range for HF

Figure 7-27

Frequency Range for VHF

Figure 7-28

Frequency Range for UHF

Figure 7-29

Frequency Range for SHF

C-band: Roughly 4 - 6 GHzKu-band: Roughly 10 -14 GHzKa-band: Roughly 20 - 30 GHz

Figure 7-30

Frequency Range for EHF

Figure 7-31

Terrestrial Microwave

Figure 7-32

Parabolic Dish Antenna

Figure 7-34

Satellite Communication

Frequency & Wavelength

30 Khz3 KHz

300 KHz

3 MHz

30 MHz

300 MHz

3 GHz

30 GHz

300 GHz

3 THz

30 THz

300 THz

3 PHz

30 PHz

300 PHz

3 EHz

30 EHz

100 Nanometers

10 Kilometers

1 Kilometer

100 Meters

10 Meters

1 Meter

10 Centimeters

1 Centimeter

1 Milimeter

100 Micrometers

10 Micrometers

1 Micrometer

10 Nanometers

1 Nanometer

100 Picometers

10 Picometers

DecreasingFrequency

IncreasingWavelength

AM Radio----

TV & FM Radio----

Microwaves----

Infrared Light----

Visible Light----

Ultraviolet Light----

X-Rays----

----Football Field

----Adult Human

----Key Chain

----Grains of Sand---Bacteria

---Viruses

---Atoms

IncreasingFrequency

DecreasingWavelength

Hz = HertzK = kilo = 103

M = mega = 106

G = giga = 109

T = tera = 1012

P = peta = 1015

E = exa = 1018

kilo = 103

centa = 10-2

mila = 10-3

micro = 10-6

nano = 10-9

pico = 10-12

RadioFrequencySpectrum

Figure 7-35

Satellite in Geosynchronous Orbit

Earth Synchronous Orbits and Patterns at Subsatellite Point

Polar

Satellite

Inclined I

Inclined i

Stationary-equatorial

0

Stationary Polar

Plane

Inclined orbits I,i

Equatorial 0

i

I

Ground Trace

Geostationary Equatorial Orbit

earth

satellite

earthsatellite

Nominal Limits for Geosynchronous Orbit

Daily Figure-8 Motion ofGeosynchronous Satellite

Active Satellite BoxTypical Station-KeepingVolume = 1.62 x 1017 m3

Mean circumference = 264,654 km

Inclination Variation:(for

km

Apogee-Perigee85 km typical

Equatorial Plane

Orbit MotionDirection and Rotation

Rate Match Earth’s

Nominal Height(from surface of earth)

35,786 km

Nominal Radius(from center of earth)

42,162 km

N

S

EW

LongitudinalMotion (E/W)

LatitudinalMotion (N/S)

Stationkeeping Window

85 km

75 km

75 k

m

0.10

Earth

Equator

• Perturbations cause “Stationary” satellite to drift from designated orbital slot• Causes varying roundtrip time (@ 285 s)• Onboard propellant used to maintain position• Fixed and broadcast service satellites positioned to 0.050

Nominal Geostationary satellite orbit

Satellite Drift NS EW

Orbit Eccentricity 0.001

0.050

Earth Coverage Contours fora Geosyncronous Satellite

00100200

Commercial Geo Satellites

0

180

90 EL90 WL

C-BandK u-BandC/K u-BandK a-BandK u/K a-BandC/K u/K a-Band

235 Satellites 6356 Commercial Transponders

Figure 7-44

Propagation Time

R

Where is the Competition?

R

R

RR

R

RR

R

R

R

INTELSATINTELSAT

BackgroundBackground

• Communications Satellite Act of 1962 led to formation of COMSAT as private corporation in 1963

• INTELSAT Formed in 1964 (11 nations)

• INTELSAT I (Early Bird) launched in April 1965

• Currently more than 150 signatories

• INTELSAT privatized 18 July 2001

Public-Switched Network Services:A Snapshot

Public-Switched Network Services:A Snapshot

• Digital service employing technology that is far more advanced than analog technology

• Allows use of digital circuit multiplication equipment that makes service cost-effective

• Trunk or thin route

• Standard A, B, C, E3, E2, F3, F2

• C and Ku-band “Single Channel per Carrier” -- Classic “circuit-based” bandwidth allocation

Does not preclude use of digital circuit multiplexing equipment

Trunk or medium route Any size antenna, any band

Digital service for thin route applications

Thin route Standard A, B C-band

Analog service which is being replaced by IDR and other digital services.

Trunk or thin route FDM/FM-Standard A, C CFDM/FM-Standard A, B C and Ku-band

IDR

TDMA

SCPC

FDM/FM & CFDM/FM

Private Network Services:A Snapshot

Private Network Services:A Snapshot

• INTELSAT-unique service which guarantees your data rate instead of the power and bandwidth

• Useful for any digital application: voice, low- and high-speed data, fax, digital television, video-conferencing

• Point-to-Point

• Point-to-Multipoint

• C-band/Ku-band or cross-strapped C/Ku

• Wide range of E/S Standards A, B, C, E3, E2, E1, F3, F2, F1

• Data-rate based, 64Kb/s to 45Mb/s

Very Small Aperture Terminal; can support the full range of business communications applications. Service can be totally customized in terms of network characteristics and earth station sizes

Point-to-Point Point-to-Multipoint Most frequently Ku-band Comply with Standard G Relatively small antennas

(1.8-2.4 meters in diameter) Providers include transaction-

based services for credit card swipes, data base access, etc

Metered, on-demand satellite service allowing customers to dynamically use bandwidth needed for voice, video-conferencing, and data applications; bandwidth reallocated every 1/2 second

Point-to-Point Point-to-Multipoint Feature of modem/router, not

the antenna or satellite system 256Kbs to 2 Mb/s (TDMA) per

modem, stackable to 32Mb/s ATM, Frame Relay, IP, SS7,

other protocols supported Example: Linkway 2000

IBS VSAT BOD

INTELSAT VII East/West Hemi,Zone & Spot Beams from 174.0 Deg East

INTELSAT VII East/West Hemi,Zone & Spot Beams from 174.0 Deg East

05

NORTHEASTZONE

EAST HEMI

Spot 1

SOUTHEASTZONE

Spot 2

Spot 2

Spot 2A

NORTHWESTZONE

SOUTHWESTZONE

WEST HEMI

INTELSAT VIII Transponder Plan

INTELSAT VIII Transponder Plan

REGION SATELLITE THIS SATELLITE TOTAL REGIONDATA BASE

SATURATIONDATE

DATABASE

TRANSMISSIONCHANNELNUMBER 2 1 1 2 3 4 5 6 7 8 9 10 11 12

CAPACITY

36 dBW 36 dBW 36 dBW 36 dBW 36 dBW 36 dBW

36 dBW 36 dBW 36 dBW 36 dBW 36 dBW 36 dBW

A

A

WESTHEMI. (H1)

EASTHEMI. (H2)

36 dBW 36 dBW 36 dBW 36 dBW 36 dBW

36 dBW 36 dBW 36 dBW 36 dBW 36 dBW

36 dBW 36 dBW 36 dBW 36 dBW 36 dBW

36 dBW 36 dBW 36 dBW 36 dBW 36 dBW

29 dBW

29 dBW

47 dBW 47 dBW 47 dBW

47 dBW 47 dBW 47 dBW

29 dBW

29 dBW

29 dBW 29 dBW

29 dBW 29 dBW{{

{A

BGLOBAL

WESTSPOT (S1)

EASTSPOT (S2)

11/12GHz

4GHz

TO

B

B

B

BN.W.ZONE (Z1)

M.W.ZONE (Z2)

N.E.ZONE (Z3)

S.W.ZONE (Z4)

INMARSATINMARSAT

INMARSATINMARSAT• Started in 1976 with COMSAT’s MARISAT

– GAPSAT• Satellite Network

– INMARSAT II (4 satellites)• One global beam• 250 Inmarsat A voice channels

– INMARSAT III (4 satellites & one spare)• 7 wide spots and one global beam• 1000 mini-M voice channels• 200 M4 64 kbps channels

– INMARSAT IV { 2004} (2 satellites & one spare) • ~200 narrow spots, 19 wide spots and one global beam• 18,000 voice channels• 2,250 M4 64 kbps channels

Four Ocean Region Coverage Satellite Coverage at 5o Angles of

Elevation

Four Ocean Region Coverage Satellite Coverage at 5o Angles of

Elevation

200 220 240 260 280 300 320 340 0 20 40 60 80 100 120 140 160 180

200 220 240 260 280 300 320 340 0 20 40 60 80 100 120 140 160 180-8

0-6

0-4

0-2

00

2040

6080

-80

-60

-40

-20

020

4060

80

582

872

584

874

581

871

583

873

Ocean Region Code (Telex)SATELLITE LOCATIONAOR EAST 18 5o W IOR 63o EAOR WEST 55 5o W POR 180o

Ocean Region Code (Telephone)

Projected INTELSAT Fleet(Dec 2004)

Projected INTELSAT Fleet(Dec 2004)

805 - 304.5E707 - 307EX-1 - 310EIX-5 - 325.5EIX-7 - 328.5E801 - 330.5EIX-6 - 332.5EIX-3 - 335.5E605 - 340EIX-1 - 342EX-2 - 359E

701 - 33EIX-4 - 60EIX-2 - 62E804 - 64E704 - 66E

702 - 180E706 - 178E705 - 176E802 - 174E

APR-2 - 110.5E

709 - 157EAPR-1 - 083E601 - 085E

Note: INTELSAT traditionally identifies their satellites by East Longitude only, not by West Longitude.

PamAmSat

LORAL GLOBAL ALLIANCE FLEETLORAL GLOBAL ALLIANCE FLEET

Figure 7-36Cellular System

Figure 7-37

Cellular Bands

Figure 7-38

Impairment Types

Figure 7-39

Attenuation

Figure 7-40

Example 7.3

Figure 7-41

Distortion

Noise

T = SNT = System Noise Temperature

No = Noise Density = kT, where k is Boltzmann’s Constant (-228.6 dBw)

N = Noise Power = kTB, where B is bandwidth.

Satellite Link Equation (From EarthTerminal Perspective)

• EIRP =

10 LOG R + EB/NO + M + L + K - G/T

• POWER REQUIRED =

10 LOG DATA RATE + ENERGY PER BIT + LINK MARGIN + FREE SPACE LOSS + BOLTZMANN’S CONSTANT - GAIN TO TEMPERATURE RATIO

Error Probability for Binary Transmission

E /N (dB)

14108642 120

1

10 -1

10 -4

10 -8

10 -2

10 -6

10 -7

10 -5

10 -3

0b

Pro

babi

lity

of

erro

r bi

nary

dig

ital

com

mun

icat

ion

exp (-x2)

2x /

12

erfc (x)

exp (-x2)2

E N

x =0

b

Antenna Gain

CONCEPT OF EFFICIENCIES

THE BORESIGHT GAIN OF AN APERTURE ANTENNA IS COMMONLY EXPRESSED AS:

WHERE: G = ANTENNA GAIN

T = OVERALL ANTENNA EFFICIENCY

A = APERTURE AREA= FREE SPACE WAVELENGTH

THE TOTAL EFFICIENCY T MAY BE PARTITIONED AS:

T = P+ I+ S + B+ X+ R

WHERE: P = NON UNIFORM PHASE LOSS

I = APERTURE AMPLITUDE ILLUMINATION LOSS

S = SPILLOVER LOSS

B = APERTURE BLOCKAGE LOSS

X = CROSS POLARIZATION LOSS

R = REFLECTOR SURFACE ACCURACY EFFICIENCY

BLOCKINGSPILLOVER

E

SCATTERING

APERTURE FIELD DISTRIBUTION

G = T = T

c2

f2A 4A2

Theoretical AntennaRadiation Pattern

Radiation Pattern

-180o 0

Bac

k L

obe

}

Wide anglesidelobe

Isotropic level

First sidelobe

Main beam

Near-in sidelobe}+180o

0

HPBW

3dB

Figure 7-42

Noise

Figure 7-43

Throughput