The 2007 Smart Radio Challenge Utah team solution

The Software Defined Radio (SDR) team at the Wireless Communications Laboratory of University of Utah was granted the best paper award in the Smart Radio Challenge; a worldwide competition that challenges student teams to design, develop and test an SDR or a cognitive radio (CR) system.  The University of Utah team was selected along with 7 other teams to continue on to the development phase of the project; the challenge originally included 43 student teams from 12 different countries. The team started working on a cognitive radio network for spectrum access for first responders in the disaster scenario from January 2007 and demonstrated their system in the 2007 Software Defined Radio Technical conference in Denver, Colorado, November 2007.

 The 2007 team members of the Smart Radio Challenge team were Peiman Amini, Ehsan Azarnasab, Salam Akoum, Xuehong Mao, and Harsha Rao. The team advisor was Professor Behrouz Farhang-Boroujeny and the team leader was Peiman Amini. The Utah team was also selected for the 2008 Smart Radio Challenge where they will work on Automated Spectrum Mapping and Channel Assignment. Three of the 2007 team members: Peiman Amini, Ehsan Azarnasab and Salam Akoum and three new team members: Pooyan Amini, Arash Farhang, and Daryl Wasden will be implementing the cognitive system for the 2008 Challenge.

The University of Utah team has developed a cognitive radio that can sense the Family Radio Service (FRS) band from 462 to 467 MHz, transmit over the unoccupied part of the spectrum. 200 subcarriers, each 25 kHz wide, are used for data and voice transmission. Using a filterbank sensing method, the radio is able to reliably sense the spectrum with a high spectral dynamic range. Consequently, very low power users can be detected in the presence of high power users on the channel.  

The Small Form Factor Software Defined Radio (SFFSDR) Lyrtech platform was selected for the implementation of the cognitive radio network. The SFFSDR platform, designed around the TMS320DM6446 digital media processor (DMP) system-on-chip (SoC) from Texas Instruments and Virtex-4 SX35 FPGA from Xilinx, gives the programmer the flexibility of targeting different silicon devices depending on their functionalities. The FPGA and DSP on the baseband processing module are used to implement signal processing algorithms while the ARM9 core is used for running the real time operating system, MAC layer, and overall system control.  The signal processing tasks are divided between the DSP and FPGA based on the availability of computational resources and the extra functionalities offered by TI and Xilinx. A novel Hardware in the Loop (HIL) technique has been developed which interfaces the board to Java and MATLAB scripts. This technique is used for both physical and MAC layer development and simplifies the implementation and testing process to a large extent.

The Utah team demonstrated the functionality of the system on November 4th to a panel of judges. A vector signal generator was used to emulate the traffic of primary users. Filterbank sensing was used to sense the band from 460.5 to 468.5. It was shown that the filterbank sensing demonstrates better performance than the FFT-based method. The cognitive network is able to move to an unoccupied part of the spectrum when interference is detected in the band that it is being used. The setup was also presented later in the Software Defined Radio Products Exhibition where some of the exhibitors were using the FRS band and thus producing interference to our embedded system. Our cognitive transceiver showed spectrum agility and robustness against interferences. The team also demonstrated the HIL technique on MATLAB and JAVA. This technique proved very useful for development as it integrates implementation with simulation.

The presentation of the solution "Implementation of a cognitive radio modem" and the posters presented at the conference can be found here: [presentation], [Poster Overview], [Poster Hardware].

A video of the demonstration of the solution and pictures of the team at the conference can be found here: [demo], [photos].

What is the Smart Radio Challenge?

The Smart Radio Challenge is hosted by the SDR forum (SDRF) - a nonprofit international industry association that supports the development and deployment of software radio technology for wireless communications systems – and sponsored by The MathWorks, Texas Instruments, Xilinx, Zeligsoft, Objective Interface, Lyrtech, PrismTech, Synplicity, and Green Hills.

The sponsors of the Challenge donated more than $100,000 worth of hardware and software to the Utah SDR team. The system is being developed on a Texas Instrument/Lyrtech Small Form Factor Software SDR Development Platform that is designed around the latest DSP and FPGA technologies.  The Wireless Communications Laboratory has also received a generous $10,000 reward from L3 communications-West for advancing in the challenge.

What is Software Defined Radio?

SDR uses software technologies running on generic hardware platforms to process radio signals. Software radios find applications in the military and cell phone services that need a wide range of changing radio protocols in real time; an enabling technology for furture wireless systems.

What is Cognitive Radio?

Cognitive radio technology has been presented as one possible solution to the spectrum access obstacle based on SDR technology. From a user’s perspective, a cognitive radio network operates identically to a standard wireless network. However, cognitive radio nodes are designed to be “aware” of the other users’ spectra, and avoid interfering with them. A cognitive radio network is built to coexist in a given portion of the spectrum with the legacy devices to which the spectrum is assigned.

Publications and technical reports

1. P. Amini, E. Azarnasab, S. Akoum, X. Mao, H. Rao, B. Farhang-Bouroujeny, "Implementation of a cognitive radio modem", 2007 Software Defined Radio Technical Conference, November 5-9, 2007, Denver/Colorado.[pdf]
2. E. Azarnasab, P. Amini, B. Farhang-Bouroujeny, "Hardware in the Loop: A Development Strategy for Software Radios", 2007 Software Defined Radio Technical Conference, November 5-9, 2007, Denver/Colorado. [pdf]
3. P. Amini, E. Azarnasab, S. Akoum, X. Mao, H. Rao, B. Farhang-Bouroujeny, "Smart Radio Challenge Final Report: Spectrum Access For First Responders", September 2007.[pdf]
4. P. Amini, D. Palchak, X. Mao, S. Talbot, S. Akoum, S. Abbasi. "Smart Radio Challenge Proposal: Spectrum Access for First Responders", September 2006. [pdf]