U.S. Team Designs Antenna to Expand Wireless Communications in Competition for Texas Instruments Cash Prize
A penchant for designing and building, combined with proficiency in math and science, first led Kim Phillips to pursue engineering as a major, even though historically engineering has been a male-dominated field. As team leader of five graduate students from Virginia Polytechnic Institute and State University (Virginia Tech), who already are splitting $10,000 from Texas Instruments in TI’s DSP (digital signal processing) Solutions Challenge, Phillips has seen her interest in engineering grow from computer engineering to electronics, moving specifically into antennas not only for television, but also for wireless communications.
Phillips, along with Keith Blankenship, Neiyer Correal, Zhong Hu, and Zeeshan Siddiqi, combined their knowledge of systems engineering, radio frequency design, antenna design, hardware interfacing, DSP theory and programming to produce a three-element smart antenna for wireless communications that could revolutionize cellular phone service. The team, based in Blacksburg, Va., 38 miles southwest of Roanoke, continue their quest for the $100,000 grand prize in the contest.
The students’ entry would allow wireless service providers such as cellular telephone providers, paging services or local loops to expand coverage, increase system capacity and improve signal quality, lowering costs for users. The design also allows cellular phone customers more "talk time" by using battery power more efficiently. Besides wireless applications, the research could guide drivers around traffic congestion or lead an ambulance to an accident faster with wireless versions of "E911," a system that not only dispatches but gives the caller’s location.
"Our designs are relatively inexpensive to implement and compatible with existing equipment of both users and wireless service providers," said Phillips. "The implementation can be scalable: it’s easy to add as many antennas as needed."
How Virginia Tech’s Adaptive Antenna Array Works
Rather than mechanically moving an antenna, such as rabbit ears on a TV, to receive a better signal, the Virginia Tech project changes the direction from which the antenna picks up signals without physically rotating the antenna. By focusing the receiving antenna "beam" only on a desired transmitter, the students are able to reduce interference to achieve better communications, Phillips explained.
Existing technology uses omni-directional antennas that pick up signals from all directions equally. With an adaptive antenna array, many antenna elements are used. By appropriately combining the signal received at each antenna, the array can point, without moving, to virtually any desired direction under the control of the DSP processor.
While radios traditionally have been implemented with analog devices, the trend is moving toward an entirely software-based radio. At the heart of the software radio is a DSP chip. DSP chips process real-world (analog) signals digitally, performing operations that otherwise would be impossible if processed entirely in analog. Because the programming of a DSP can be modified easily, upgrades or changes to the algorithm can be accomplished quickly. As a result, the DSP is able to manipulate the shape of the array beam pattern through signal processing. The Virginia Tech students used TI’s TMS320C541 DSP evaluation board to collect data and perform the intense number-crunching needed to create and move the antenna beam pattern.
Most of the students had worked with DSPs prior to the current competition. Virginia Tech offers classes that use TI DSPs for basic DSP study, as well as courses on implementing communication systems on DSP hardware. In addition, the Mobile and Portable Radio Research Group (MPRG) at Virginia Tech, of which the team--except for Siddiqi--is a member, uses DSPs to implement advanced wireless communication research projects.
Despite their previous experience with DSPs, the Virginia Tech team found TI’s DSP Challenge project "proof of concept" for their research efforts and a way to acquire design experience with fixed point DSP processors. "We can directly apply our experience to the next generation wireless communication systems," Phillips said. "It is very likely that we will apply our knowledge in the design and implementation of new commercial wireless products and systems."
Backgrounds of Participants
Blankenship holds a bachelor of science degree in applied math from Virginia Commonwealth University and a doctorate in physics from Virginia Tech. Correal completed undergraduate work at the Pontifical Javeriana University in Columbia, South America, and his master of science degree at Old Dominion University, Norfolk, Va. Hu earned a bachelor of science degree in physics from University of Science and Technology of China and a master of science degree in physics from Virginia Tech. Phillips earned an associate degree in computer engineering technology, then a bachelor of science in electronics engineering technology from Capitol College, Laurel, Md. Siddiqi holds a bachelor of science degree in electrical engineering from Tennessee Technologic University and a master’s degree from Virginia Tech. He is now employed with Alcatel in Raleigh, N.C.
Jeffrey H. Reed, an associate professor with the Bradley Department of Electrical and Computer Engineering and an associate director of the MPRG at Virginia Tech, advised the students for the TI DSP Challenge project. "We are very proud of our DSP team. They worked hard, often through the night, to put this project together," he said.
Reed is a member of the Center for Wireless Telecommunications at Virginia Tech. He earned his bachelor of science, master of science and doctorate, all from the University of California at Davis in 1979, 1980 and 1987 respectively. From 1980 to 1986, he worked for Signal Science, Inc., a small consulting firm specializing in DSP and communication systems. Reed was an independent consultant and part-time faculty member at his alma mater after graduating. He joined Virginia Tech in 1992.
Reed specializes in spread spectrum, position location, digital signal processing, interference rejection, modem design, smart antennas and software radios. He is the co-editor of five textbooks and the author of numerous journal papers and conference presentations. He is currently writing a book on software radios.
TI's DSP Solutions Challenge is a worldwide competition to develop the most innovative and functional design using TI DSPs. Created to address the industry-wide shortage of design engineers with DSP experience, TI has developed and invested in this international recognition system to encourage research and interest in the technology.
The DSP market is growing at an average annual rate of 30%, according to the market research firm Forward Concepts. Today's DSP solutions market is roughly $5 billion and has grown more than 40% per year since 1988. This market growth projection exceeds that of the semiconductor industry in general.
Related Documentation: