December 23, 2008
ECE graduate students Reginald Cooper, Kevin Borries, and Xiaohui Wang came away winners of the Second Annual Smart Radio Challenge sponsored by the Software Defined Radio Forum, a non-profit international industry association dedicated to promoting the success of next generation radio technologies.
The team took home three awards: Best Design, First Prize in their category, and the Grand Prize. The group is one of 43 student teams from 12 different countries that originally entered the contest in 2007, and one of six finalists.
The Smart Radio challenge is a worldwide competition in which student engineering teams design, develop and test software defined and cognitive radio technologies that address specific problems relevant to the advanced wireless community. The theme of this year's challenge required teams to address one of three defined problems: 1) extending the range of a wireless network; 2) mapping frequencies and locations of RF emitters; and 3) preparing a Rapid Waveform Development. Winners receive cash prizes in the form of scholarship money. The ECE team, Team Plaid, was advised by ECE Professor Dan Stancil.
"I am really excited for the students," said Stancil. "This is the result of a lot of hard work and creativity by each of the team members. Reginald especially deserves credit for enthusiastically organizing and leading the effort."
A Software-Defined Radio (SDR) is a radio where components that have typically been implemented in hardware (i.e. mixers, filters, amplifiers, modulators/demodulators, detectors. etc.) are instead implemented using software on a personal computer or other embedded computing devices. While the concept of SDR is not new, the rapidly evolving capabilities of digital electronics are making practical many processes that were once only theoretically possible.
In the long term, software-defined radios are expected to become the dominant technology in radio communications. It is the enabler of the cognitive radio, a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users.
Software defined radios have significant utility for the military and cell phone services, both of which must serve a wide variety of changing radio protocols in real time.
ECE's Team Plaid addressed Problem 2 in the Smart Radio Challenge that concerns automated spectrum mapping. The challenge was to develop a smart radio system that could effectively communicate information on spectrum utilization through a cooperative spectrum access protocol.
Teams were to develop a secondary-user cognitive transceiver system that can detect primary-user signals operating in the 2.4 GHz ISM band and determine the occupied spectrum, transmission times and geographical locations to sufficient resolution to avoid interference with legacy systems while operating within that band.
Team Plaid has designed a wireless radio network that can avoid over crowded wireless environments and use the 2.4 GHz ISM band as secondary-users.
"Most cellular phone users have had the displeasure of experiencing dropped phone calls," said Cooper. "Sometimes, this is caused by too many subscribers being on a given cellular providers' network at the same time. This makes the wireless environment very crowded and congested, and this eventually leads to dropped calls. Dynamically reconfigurable secondary user schemes are promising approaches to addressing such channel shortages."
Team Plaid's network of wireless radios is able to locate wireless environments that are not being use by other radios, and deploy applications such as text, voice, and picture messaging. Their network is able to locate these unoccupied wireless environments, known as unused spectrum, through a method known as spectrum mapping.
Using this method, some of the radios in the wireless network constantly sense and gather spectral, temporal, and spatial information about the wireless environment. This information is then processed by another radio to determine what part of the spectrum is not being used at a given time or spatial location, allowing the network to use it.
All the radios used by Team Plaid were Software Defined Radios (SDRs). SDRs have a hardware and software component. The main SDR hardware component used by Team Plaid was the Universal Software Radio Peripheral (USRP) from Ettus Research, a company started by ECE alumnus Matt Ettus. The USRP was loaned to the project by ECE and CS Professor Peter Steenkiste's research group. They also used a wideband signal conversion module (SCM) developed at Carnegie Mellon in collaboration with Steenkiste and his former student Glenn Judd. Instead of using the typical GNU Radio software setup that operates in Linux, Team Plaid devised a method that allowed them to operate on a Windows platform in MATLAB.
ECE graduate students Reginald Cooper, Kevin Borries, and Xiaohui Wang, winners of the Second Annual Smart Radio Challenge.