1 / 13

Satellite Radio: The Next Communications Revolution?

Satellite Radio: The Next Communications Revolution?. David Bultman. Challenges In Satellite Radio . There are three general problems with satellite reception: Blockages Foliage Multipath Fading. Blockages. The target of satellite radio is a mobile platform

Samuel
Télécharger la présentation

Satellite Radio: The Next Communications Revolution?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Satellite Radio: The Next Communications Revolution? David Bultman

  2. Challenges In Satellite Radio There are three general problems with satellite reception: • Blockages • Foliage • Multipath Fading

  3. Blockages The target of satellite radio is a mobile platform • This rules out the use of special high gain antennas and expensive satellite tracking systems • The important factors to think about when considering blockages are the movement of the receiver, the movement of the satellite, and the angle of elevation of the satellite

  4. Foliage Foliage is similar to a blockage with a few exceptions • Foliage can block or attenuate a signal • The amount of attenuation can depend on the type of foliage, the frequency of the signal, and the incident angle • Foliage can also reflect a signal with a random amount of attenuation and phase shift

  5. Multipath Fading • Multipath Fading occurs multiple forms of the original signal are received

  6. Solutions – Spatial Diversity Spatial Diversity = Instead of having a single signal source, use multiple signal sources spread out • Spatial Diversity helps fix all three of the problems

  7. Solutions – Frequency Diversity Frequency Diversity = Sending the same information on two separate and unrelated frequencies (preferably also spatially diverse) • Frequency Diversity is aimed at fixing multipath fading

  8. Solutions – Time Diversity Time Diversity = Delaying one of two spatially diverse signals in time before its broadcast • Time Diversity is aimed at eliminating audio outages when both broadcast signals are blocked simultaneously

  9. Solutions – Repeater Stations Repeater Stations are used in areas where even the combination of the other three solutions may not yield a “good” signal

  10. XM Radio’s System • Two geostationary satellites with a 45 degree angle of elevation • Each satellite emits about 10MW of signal energy • Approximately 1500 low power repeater stations serving 70 markets

  11. Sirius Radio’s System • Three satellites in an inclined elliptical orbit • Each satellite spends about 16 hours over the US, with two satellites always above the equator

  12. Sirius Radio’s System • The satellites are inclined at 60 degrees • The satellites are of lower power than XM Radio’s • 105 high power repeaters serving 46 markets

  13. The Future? • From all indications the audio quality is superb with both providers • The tests will be subscriber numbers and the possibility of terrestrial radio adding digital signals to their broadcasts to compete

More Related