Adaptive antennas offer single best technology for increasing spe...

antennas -- “smart” antennas -- use computer processing to adapt radiation pattern in real time, he said. Goal is to optimize focus of energy from base station to cell where subscriber is located and minimize interference to adjacent cells, Goldburg said. Systems also use processing to “try to listen selectively” to reduce effect of interference from adjacent channels. Rather than single dish, adaptive antennas use array of smaller low-power antennas functionally tied together with processing power, he said. As result, carrier “can support the same communication service with much less total power, something that [to regulators] has safety and RF exposure considerations,” Goldburg said. More significant benefit is spectrum reuse, ability to reuse same channel without buffer of numerous adjacent cells. Extreme case is fixed wireless network using time division duplexing where adaptive antenna increases spectral efficiency up to 20 times and provider “can actually reuse spectrum within a cell,” he said. Even in frequency division duplexing mobile voice service such as GSM, adaptive antenna technology promises up to 6 times improvement. He said technology was in early stage of development as necessary computer power -- antenna array could generate 1 Gbps data rate to interpret -- had been available and affordable only in last few years. Technology is “generally applicable to all air interfaces,” Goldburg said. “Efficient use of spectrum is critical due to increasing scarcity for mobile wireless applications. In the total range of spectrum only a relatively small amount is useful for mobile applications” ranging from 500 MHz to 2.5 GHz. “There is a lot of pressure on this 2GHz of spectrum from public safety, cell services, SMR, paging and military users, not to mention radio astronomers who can’t relocate the frequency of a star,” he said. New 3rd generation wireless data service will further increase need for spectrum -- resource that is yet to be allocated by FCC. Spectrum efficiency directly affects operating cost structure for wireless service, Goldburg said: “It determines the amount of spectrum required, number of base stations, number of sites and cost of site maintenance and, ultimately, consumer pricing and affordability of a service.” Increasing spectral efficiency reduces barriers to new operators and services because operators need to purchase less spectrum, he said.