Presentation On “Overview of Satellite Communication System” Presented By: Rashed Ahmed Daffodil International University..

Satellite Communication In Satellite communication , signal transferring between the sender and receiver is done with the help of satellite.

Communication Satellite A Communication Satellite can be looked upon as a large microwave repeater It contains several transponders which listens to some portion of spectrum, amplifies the incoming signal and broadcasts it in another frequency to avoid interference with incoming signals.

Satellite

Satellite Missions

Frequency Bands Different kinds of satellites use different frequency bands. L–Band: 1 to 2 GHz, used by MSS S-Band: 2 to 4 GHz, used by MSS, NASA, deep space research C-Band: 4 to 8 GHz, used by FSS X-Band: 8 to 12.5 GHz, used by FSS and in terrestrial imaging, ex: military and meteorological satellites Ku-Band: 12.5 to 18 GHz: used by FSS and BSS (DBS) K-Band: 18 to 26.5 GHz: used by FSS and BSS Ka-Band: 26.5 to 40 GHz: used by FSS

Communication link Downlink Uplink The link from a satellite down to one or more ground stations or receivers Uplink The link from a ground station up to a satellite. Some companies sell uplink and downlink services to television stations, corporations, and to other telecommunication carriers. A company can specialize in providing uplinks, downlinks, or both.

Uplink and Downlink

Satellite Uplink and Downlink

Direct to User Services one way Service (Broadcasting) Two way Service (Communication)

How do Satellites Work ? Two Stations on Earth want to communicate through radio broadcast but are too far away to use conventional means. The two stations can use a satellite as a relay station for their communication One Earth Station sends a transmission to the satellite. This is called a Uplink. The satellite Transponder converts the signal and sends it down to the second earth station. This is called a Downlink.

Satellite Orbit

Satellite Orbit LEO MEO GEO HEO

Satellite Orbits

Satellite Orbit

Satellite Orbit Picture

Satellite Orbits

How Satellites are used ? Service Types Fixed Service Satellites (FSS) Example: Point to Point Communication Broadcast Service Satellites (BSS) Example: Satellite Television/Radio Also called Direct Broadcast Service (DBS). Mobile Service Satellites (MSS) Example: Satellite Phones

Advantages of Satellite Communication Can reach over large geographical area Flexible (if transparent transponders) Easy to install new circuits Circuit costs independent of distance Broadcast possibilities Temporary applications (restoration) Mobile applications (especially "fill-in") Terrestrial network "by-pass" Provision of service to remote or underdeveloped areas User has control over own network 1-for-N multipoint standby possibilities

When to use Satellites When the unique features of satellite communications make it attractive When the costs are lower than terrestrial routing When it is the only solution Examples: Communications to ships and aircraft (especially safety communications) TV services - contribution links, direct to cable head, direct to home Data services - private networks Overload traffic Delaying terrestrial investments 1 for N diversity Special events

Thanks to All..