Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Engineers from WorldSpace and Fraunhofer Institute Conduct Successful Tests in Satellite Time Divers

09.08.2000


WorldSpace and Fraunhofer IIS-A test Mobile Reception in Automobiles

ERLANGEN/WASHINGTON, D.C. (August 8, 2000) - A team of engineers from WorldSpace Corporation and the Fraunhofer Institut Integrierte Schaltungen have completed a successful test and demonstration of two techniques which together set the stage for WorldSpace receivers to operate in automobiles throughout the WorldSpace coverage area. These techniques are Time Diversity reception technology using current WorldSpace satellites and Multi-carrier Modulation (MCM) terrestrial rebroadcast technology for seamless reception in urban areas.

Time Diversity was achieved through the use of two broadcast channels from the AfriStar satellite, one channel delayed by 4.32 seconds with respect to the other. Time Diversity was used to eliminate blockages of the satellite transmission caused by obstacles such as bridges, trees and buildings that interrupt the line of sight to the satellite while in a moving vehicle. The method works by normally listening to the late channel and storing the early channel in a 4.32-second delayed memory. When a blockage occurs the receiver switches to the stored early channel in which the delayed early programme is precisely synchronized with the content of the blocked late channel, thus eliminating any blockage of the flow of programme content. The same process also works with data transmissions thus preventing the loss of any information content.

The MCM technology was demonstrated by conducting ground retransmissions of the same broadcast channels received from the satellite through three properly located terrestrial repeaters in Erlangen. The tests successfully demonstrated the efficacy of the MCM technique to allow seamless reception even in areas with heavy blockages of the direct signal path.

Taken together, these tests demonstrated the ability to receive the WorldSpace signal without any interruption through highway underpasses as well as in urban areas with tall buildings and structures. This is the first time that satellite Time Diversity and associated MCM retransmissions of the satellite signal have been demonstrated

"These tests represent an important step towards expanding our system capabilities to the full range of environments, whether portable, fixed or mobile throughout the WorldSpace coverage areas," said WorldSpace Chairman and CEO Noah Samara.

Additional tests and demonstrations are to be performed in Pretoria South Africa during September 2000 using a terrestrial single frequency network of MCM transmitters combined with Time Diversity satellite reception from the AfriStar satellite. Mobile receivers will compare the signal quality from the terrestrial and satellite broadcast channels and automatically select which signal best provides seamless reception between satellite reception areas and terrestrial reception areas.

About WorldSpace Corporation

Headquartered in Washington, DC, WorldSpace was founded in 1990 to provide direct satellite delivery of digital audio and multimedia services to the emerging markets of the world, including Africa, the Middle East, Asia, Latin America, and the Caribbean. The WorldSpace satellite network will consist of three geostationary satellites. The first two satellites, AfriStar and AsiaStar, were successfully launched October 28, 1998 and March 21, 2000 respectively. The third satellite, AmeriStar, will follow in 2001. Each satellite has three beams with each beam capable of delivering more than 40 channels of crystal clear audio and multimedia programming directly to portable receivers. Once completed, this unique global service will transmit quality information, education and entertainment programming to a service area that includes 4.6 billion people. For more information, visit our web site at www.worldspace.com.

About Fraunhofer IIS-A

Fraunhofer Institute for Integrated Circuits, Applied Electronics IIS-A is one of the largest R&D institutions worldwide dealing with digital broadcasting systems and audio compression technologies. About 120 scientists out of 350 employees are working in these business fields. The institute has its headquarters in Erlangen, Germany.

From the beginning, Fraunhofer IIS-A was involved in the development of the WorldSpace system including system definition and commercial uplink equipment. Fraunhofer IIS-A has also brought in its MPEG-2 Layer 3 (MP3), the audio coding standard used in the Internet. For more information, visit our web site at www.iis.fhg.de/dab

Weitere Informationen finden Sie im WWW:

Elvira Gerhäuser |

More articles from Information Technology:

nachricht Smart Computers
21.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht AI implications: Engineer's model lays groundwork for machine-learning device
18.08.2017 | Washington University in St. Louis

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>