Spectrum-ShaRC (spectrum sharing radio contest) will take place during the 2015-16 academic year, with a final round in June 2016. The contest will use the cognitive radio test system (CRTS), a framework developed for cognitive radio experimentation and performance measurement, and Virginia Tech’s Internet-accessible CORNET cognitive radio testbed to measure performance of student-designed cognitive or adaptive dynamic spectrum access radios in challenging operational environments. Teams will begin with ready-to-run software, provided at no cost by the contest organizers. This software will consist of a reference waveform implemented using open-source software-defined radio (SDR) software such as liquid-dsp and / or GNU Radio, and will serve as a starting point for the students’ own designs to ensure that the contest provides both a low barrier to entry and potential for extensive innovation.
As communications systems gradually move towards 4G using long-term evolution (LTE) technology, LTE nodes need to be integrated into the CORNET testbed to be able to train engineers and students on this emerging technology and its evolution. This proposal aims to extend and augment the capabilities of our existing testbed so that it can support LTE-related experiments relevant to the DoD. Read more.
This is a mpg4 format.
Also available on our YouTube Channel!
Also available on our YouTube Channel and is linked directly in ogv format (recommended) for your convenience.
One node acts as a simplified LTE base station (eNode-B). It generates the primary and secondary synchronization sequence (PSS and SSS) as well as the physical broadcast channel (PBCH). Another three close-by CORNET nodes act as LTE user equipment (UE). UE 1 (middle left terminal) is the closest to the eNode-B. UE 2 (middle right terminal) is a farther away from the eNode-B UE 3 (lower terminal) is farthest away from the eNode-B. UE1 and UE2 sense the spectrum around the LTE carrier frequency, which was chosen as 440 MHz. The signal appears stronger at UE1, due to its closer proximity and less power loss due to propagation. UE3 executes the UE side waveform, which first synchronizes to the base station (finding the PSS and SSS) for time alignment and frequency offset correction. Then the broadcast channel can be located and decoded, containing the system frame number—10 bit number, incremented every 10 ms—, among others. The decoding of the broadcast channel involves channel equalization via pilot or reference signals. The constellation diagram shows the QPSK symbols after equalization. Next, we stop the spectrum sensing at UE2 and execute the receiver waveform—the same waveform as UE3. Note how the symbols are closer, because of higher SNR due to proximity of UE2. Nevertheless, all bits are correctly decoded for UE3 (see lower terminal). Finally UE2 stops sensing ad starts its receiver processing chain. It synchronizes and correctly decodes the information on the broadcast channel. UE1 and UE3 momentarily fall out of sync, but resynchronize again.
This is an interactive version of the CORNET 3-D testbed. Internet Explorer and Firefox typically will not display the embedded graphic. If the graphic is not displayed here please click on the link above.
CORNET3D can teach students about strategies for optimal use of spectrum resources through a game—by providing them with real-time scoring based on their choices for radio transmission parameters. You must use either Google Chrome, or Opera to view the 3-D Graphic. IE9 will support WebGL with the additional plug-ins InstantReality plug in, Flash 11, or Chrome Frame. Use your mouse to rotate the graphic for a complete view of the testbed floors and nodes.
(Hint: Type the letter "R" to reset the graphic)
There is a narrated version available on Nikita's YouTube Channel
Static floor plan schematics are also available: