satellite communication

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EVOLUTIONIZED SATELLITE COMMUNICATION - Advancements communication:

EVOLUTIONIZED SATELLITE COMMUNICATION - Advancements communication By Saranraj.G Saravanakumar.K pre –final year AUTT- Panruti campus

Slide 2:

Basic of Satellite Type of Satellite Geosynchronous orbit Frequency reuse TDMA in satellite Merits and Demerits OVERVIEW

What is Satellite?:

What is Satellite? Isaac Newton noticed first, that if we throw an object on Earth horizontally with big enough velocity, it will not fall down, but will circulate around Earth indefinitely (apart from Gravitational force)

How do Satellites Work:

How do Satellites Work A satellite receives a microwave signal from a ground station on the earth (the uplink) , then amplifies and retransmits the signal back to a receiving station on earth at a different frequency (the downlink).

Uplink:

Satellite Ground station -Transmitting Ground station -Receiving Uplink Downlink FDMA TDMA

Type of Satellites:

Type of Satellites 1957 first satellite SPUTNIK(Russia) 1958 first active communication satellite TELSTAR 1 1960 ECHO 1(U.S) 1963 first geostationary satellite SYNCOM 2(NASA) 1965 first commercial geostationary satellite Satellite „ Early Bird“(INTELSAT I): 240 duplex telephone channels or 1 TV channel, 1.5 years lifetime 1979 first mobile satellite telephone system INMARSAT 1993 ACTS(NASA)

Satellite orbits:

Satellite orbits GEO - Geosynchronous earth orbit MEO- medium earth orbit LEO- low earth orbit

Geosynchronous orbit:

Geosynchronous orbit A communication satellite is in geosynchronous orbit , which means that it is orbiting at the same speed as the earth is revolving. The satellite stays in the same position relative to the surface of the earth, so that the broadcasting station will never lose contact with the receiver.

Satellite frequency bands:

Satellite frequency bands

Frequency Reuse:

Frequency Reuse It used for high data rate satellite communication system Provides for dual polarization & spatial reuse of transmit and receive beams to provide for 12-fold increase in the effective bandwidth and no of users that may be supported by the system

Frequency Reuse (cont.):

Frequency Reuse (cont.)

TDMA in Satellite:

TDMA in Satellite TDM(Time Division Multiple). is a method where several message signals are multiple to send it over a single channel. To make it simple, here time is divided among the individual message signals. TDM- Data from same source TDMA- Data from different source

TDMA (cont.):

TDMA (cont.) Single data Multiple data

Iridium system :

Iridium system Iridium is designed to provide direct world wide voice data communication using handheld terminals , a service similar to cellular telephony but on a global scale. It have 66 satellite in six LEO orbit Note

Slide 15:

Merits It cover the whole global system Higher Bandwidths are available for use. MEMS used for miniaturized an antenna size Demerits Launching satellites into orbit is costly. Bandwidth is gradually becoming used up. Propagation delay is large than terrestrial communication.

Conclusion:

Conclusion Looking at the rate of advancement in satellite communication one would foresee the use of satellites in every field where communication is required such as relaying television and radio signals.

Slide 17:

Thank you