Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Call Forwarding: New NIST Procedure Could Speed Cell Phone Testing

04.03.2010
By accurately re-creating the jumbled wireless signal environment of a city business district in a special indoor test facility, researchers at the National Institute of Standards and Technology (NIST) have shown how the wireless industry could lop hours off the process of testing the capabilities of new cellular phones. The NIST techniques also could simulate complex real-world environments for design and test of other wireless equipment.

As described in a forthcoming paper,* NIST researchers conducted tests in downtown Denver, Colo., to measure precisely the clustering of signal reflections from radio waves bouncing off one or more multi-story buildings multiple times before reaching a distant receiver. The researchers replicated this environment indoors using a “reverberation chamber,” a room with highly reflective surfaces and a big, slowly rotating paddle that automatically alters signal paths.

First, researchers feed a wireless transmitter’s signal into a device called a fading simulator, which is adjusted to re-create the timing and strength of the reflections of an outdoor urban area. The output then is fed into the reverberation chamber, where signal reflections decay exponentially over time, creating a cluster of signals similar to that observed in the field tests.

Industry certification of cell phones currently requires tests of parameters such as total radiated power using the opposite of a reverberation chamber, a room called an anechoic chamber that is lined with materials that absorb radio waves and reflect as little as possible. This testing takes about a day, requiring dozens of measurements of cell phone directional power from multiple angles. By contrast, an equivalent set of tests could be performed in about an hour in a reverberation chamber, according to NIST engineer Kate Remley, a senior author of the new paper. Reverberation chambers also could be used to measure cell phone receiver sensitivity, although currently there would be no time savings for this test, Remley says. Many industry testing practices are established by CTIA-The Wireless Association, the trade group representing the wireless industry.

NIST is studying new applications for reverberation chambers, which have typically been used to measure electronic equipment’s immunity to radio-frequency interference. By adjusting the reflectivity of the chamber through selective use of signal-absorbing material, researchers have found they can “tune” the signal decay time to simulate the conditions found in real-world environments. NIST researchers expect the new method will be useful for test and design of wireless devices such as cell phones, notebook computers equipped with wireless links, as well as new technology such as wireless beacons being developed for the emergency responder community.

The Denver tests were conducted in 2009. NIST researchers measured the power delays between a transmitter and a distant receiver positioned on streets lined with buildings three floors high or taller and a flat, single-layer parking lot. Most buildings were constructed of glass, steel, and concrete.

* H. Fielitz, K.A. Remley, C.L. Holloway, Q. Zhang, Q. Wu and D.W. Matolak. Reverberation-chamber test environment for outdoor urban wireless propagation studies. IEEE Antennas and Wireless Propagation Letters. Forthcoming.

Laura Ost, laura.ost@nist.gov, (303) 497-4880

Laura Ost | Newswise Science News
Further information:
http://www.nist.gov

More articles from Communications Media:

nachricht New Technologies for A/V Analysis and Search
13.04.2017 | Fraunhofer-Institut für Digitale Medientechnologie IDMT

nachricht On patrol in social networks
25.01.2017 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO

All articles from Communications Media >>>

The most recent press releases about innovation >>>

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

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>