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Chapter 17Chapter 17Cellular Telephone and Satellite Cellular Telephone and Satellite

NetworksNetworks

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17.1 Cellular Telephony17.1 Cellular Telephony

Frequency Reuse Principle Transmitting Receiving Handoff Roaming First Generation Second Generation

Third Generation

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Cellular SystemCellular System

A cellular service area is divided into cells.

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Frequency Reuse PatternFrequency Reuse Pattern

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First GenerationFirst Generation

AMPS (Advanced Mobile Phone System) is an analog c

ellular phone system using FDMA

operating in the ISM 800 Mhz

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AMPS reverse communication bandAMPS reverse communication band

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Second-generation cellular phone systemsSecond-generation cellular phone systems

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D-AMPSD-AMPS

D-AMPS, or IS-136, is a digital cellular phone system using TDMA and FDMA.

• A second-generation cellular phone system that is a digital version of AMPS

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GSMGSM

Global System for Mobile Communication (GSM) is a

second-generation cellular phone system used in

Europe

bands

= =

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GSM (2)GSM (2)

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Multiframe ComponentsMultiframe Components

GSM is a digital cellular phone system using TDMA and FDMA.

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IS-95IS-95

Interim Standard 95 is a second-generation cellular

phone system based on CDMA and DSSS

IS-95 forward transmission

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IS-95 reverse transmissionIS-95 reverse transmission

IS-95 is a digital cellular phone system using CDMA/DSSS and FDMA.

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Third GenerationThird Generation

The main goal of third-generation cellular telephony is

to provide universal personal communication.

Internet Mobile Communication for year 2000 (IMT-2000)

IMT-2000 radio interfaces

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17.2 Satellite Networks17.2 Satellite Networks

• Orbits

• Three Categories of Satellites

• GEO Satellites

• MEO Satellites

• LEO Satellites

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Satellite OrbitsSatellite Orbits

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ExamplesExamples

Example 1Example 1

What is the period of the moon according to Kepler’s What is the period of the moon according to Kepler’s law?law?

SolutionSolution

The moon is located approximately 384,000 km above the earth. The radius of the earth is 6378 km. Applying the formula, we getPeriod = (1/100) (384,000 + 6378)1.5 = 2,439,090 s = 1 month

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ExamplesExamplesExample 2Example 2

According to Kepler’s law, what is the period of a satAccording to Kepler’s law, what is the period of a satellite that is located at an orbit approximately 35,78ellite that is located at an orbit approximately 35,786 km above the earth?6 km above the earth?

SolutionSolution

Applying the formula, we get

Period = (1/100) (35,786 + 6378)1.5 = 86,579 s = 24 h

A satellite like this is said to be stationary to the earth. The orbit, as we will see, is called a geosynchronous orbit.

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Satellite CategoriesSatellite Categories

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Satellite orbit altitudeSatellite orbit altitude

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Satellite frequency bandSatellite frequency band

Band Band Downlink, GHzDownlink, GHz Uplink, GHzUplink, GHz Bandwidth, MHzBandwidth, MHz

LL 1.51.5 1.61.6 1515

SS 1.91.9 2.22.2 7070

CC 44 66 500500

KuKu 1111 1414 500500

KaKa 2020 3030 35003500

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Satellites in geosynchronous orbitSatellites in geosynchronous orbit

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GPSGPS

24 satellites in six orbits.

Medium-Earth-orbit (MEO) satellites that provide time

and location information for vehicles and ships.

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LEO (Lowor-Earth Orbit) SatellitesLEO (Lowor-Earth Orbit) Satellites

UML : User Mobile Link, GWL : Gateway Link, ISL : Intersatellite Link

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Iridum Constellation Iridum Constellation

The Iridium system has 66 satellites in six LEO orbits, each at an altitude of 750 km.

Providing direct universal voice and data communications for handheld terminals.

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TeledesicTeledesic

• Teledesic has 288 satellites in 12 LEO orbits, each at an altitude of 1350 km.

• Teledesic satellites are low-Earth-orbit satellites that will provide universal

broadband Internet access.

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Questions !Questions !