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
ERC: Six Advanced Grants for Helmholtz
10.04.2017 | Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren
German Federal Government Promotes Health Care Research
29.03.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
25.04.2017 | Physics and Astronomy
25.04.2017 | Materials Sciences
25.04.2017 | Life Sciences