Jones's research found in next generation digital television system
By Bridget Maiellaro and Laurel Bollinger ECE Illinois
November 6, 2008
- Prof. Doug Jones Active Constellation Extension method will be used in the newest generation digital video broadcast standard.
- Jones has been working on the ACE method for 10 years.
- The new method reduces peak power level in wireless transmission of digital bits.
“As a professor you don’t really have a direct way of getting your stuff out there, so it’s really exciting to think that your research is actually going to be used,” said ECE Professor Douglas L. Jones.
Jones’s Active Constellation Extension (ACE) method for peak power reduction has been included in the new second-generation digital video broadcast standard, which will be used for digital television in a majority of countries across the world. It is the first time any of Jones’s research has appeared in a widely used product.
He has been working on this method for the past 10 years. With teams of graduate students and a lot of patience, his theory is now being put to work. Jones says that it is all about reducing peak power levels in the wireless transmission of digital bits. The higher the signal peaks, the more energy it takes for the transmitter to accommodate it. A peak is the highpoint in the radio wave, so if this signal is not smooth and has higher peaks and lower peaks, it takes more energy to operate the transmitter.
Jones' ACE method extends orthogonal frequency-division multiplexing (OFDM). OFDM sends many bits simultaneously but at a slower rate for each; the total transmission rate in bits per second is the same, but each individual bit is transmitted over a longer time period, thus reducing many of the problems associated with high-speed communications.
Jones’ ACE contribution has been picked up by the Digital Video Broadcasting Project (DVB), an industry-led group of more than 260 broadcasters, manufacturers, network operators, software developers, regulatory bodies, and others. They introduced their new transmission system for global television, the DVB-T2, in June. The new system, based on the organization’s original DVB-T, promises a 30 to 50 percent increase in capacity in equivalent reception conditions, according to a DVB press release. Jones's contribution may reduce the energy needed to operate the transmitter by up to 30%.
“I actually didn’t know that my research was being used,” said Jones. “We just did the work and published it in some communications conferences and journals.”
Jones says that this method will become increasingly important in the future, especially with the large amount of wireless technology. Most new wireless systems use OFDM, and Jones hopes that one benefit of his method will be longer battery life for products like cell phones. He is also hoping to reduce the energy used on sending TV signals for digital television.
“If we can reduce that energy output by about 30%, it could be a huge savings, both of energy and financially,” he said.
Jones said that more and more communications devices are taking up larger factions of our energy usage.
“We need to start thinking from the beginning every time we introduce some new electronics technology, how can we make it energy efficient,” Jones said. “I think this is one way that we can have the advantages of these newer communications schemes and also reduce the power consumption.”
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