They are also expected to play a major role in tactical communications for the U.S. Navy and for the Department of Defense,” said Thomas Hou, professor of electrical and computer engineering in the College of Engineering at Virginia Tech.
However, a major technical obstacle remains and that is the availability of frequency space on an already crowded wireless array of networks.
Hou and his colleagues Wenjing Lou of computer science and Hanif Sherali of industrial and systems engineering have proposed some novel solutions for spectrum sharing that may avoid the presence of interference.
Both the National Science Foundation (NSF) and the Office of Naval Research (ONR) are funding their work on efficient spectrum sharing, although each grant addresses different types of problems and different application domains.
Cognitive radios are valued because they will configure to their environment and their user’s needs. The new cognitive radios are similar to living creatures in that they are aware of their surroundings and understand their own and their user’s capabilities and the governing social constraints. Under development for more than a decade, cognitive radio transmission still faces challenges.To address some of these issues, the NSF project, valued at $500,000, is aimed at a much higher efficiency sharing of the spectrum where the networks actually coexist.
“But if we can somehow configure secondary nodes not to be felt by the primary nodes, then we can achieve transparent coexistence,” Hou added. This is the main research theme of the NSF grant.
Specifically, the team plans to explore the potential of the simultaneous activation of a secondary network with the primary network, as along as the interference produced by secondary nodes can be properly controlled (e.g., canceled) by the secondary nodes. That is, secondary users share the spectrum in a much more aggressive manner than the interference-avoidance paradigm.
“Here, secondary nodes are allowed to be active as long as they can cancel their interference to the primary nodes in such a way that the primary nodes do not feel the presence of the secondary nodes. “Activities by the secondary nodes are made in a transparent or invisible way to primary nodes,” Hou explained.
Under this paradigm, secondary nodes use powerful physical layer capabilities to handle interference cancellation. “Further, the burden of this interference cancellation will solely rest upon the secondary nodes so as to be truly transparent or invisible to primary nodes. As expected, such a paradigm has the potential of offering much greater spectrum efficiency and network capacity than those under the existing paradigm,” Hou added.
The second grant, awarded by the ONR and valued at $300,000, will allow Hou, Lou and Sherali to look at specific spectrum-sharing methods for tactical communications.
In this project, they will explore a new spectrum-sharing method for DoD and the Navy’s cognitive radio ad hoc networks. The proposed method is called cooperative sharing, specifically targeted to the application scenario where the DoD or Navy’s ad hoc network, in the role of a secondary network, wishes to access the radio spectrum in a friendly environment where the underlying spectrum is owned by allied coalition forces network.With this method, a secondary network and the primary network share each other’s network resource or nodes in a cooperative and friendly manner. “Although packets from the primary network may still enjoy priority over packets from the secondary network, packets from either network will take advantage of the nodes in the other network on their way to their destinations,” Hou explained.
Hou is the co-editor of Cognitive Radio Communications and Networks: Principles and Practice, adopted as a textbook by a number of universities around the world. Lou has a NSF CAREER Award based on the study of wireless networks. Sherali, a member of the National Academy of Engineering, is world-renowned for his abilities in designing optimization algorithms.
Lynn A. Nystrom | Newswise
RNA: a vicious pathway to cancer ?
14.08.2017 | Goethe-Universität Frankfurt am Main
Extensive Funding for Research on Chromatin, Adrenal Gland, and Cancer Therapy
28.06.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
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,...
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...
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...
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...
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...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences