FCC clears way for SDR

Recommendations designed to help adoption of technology Software-defined radio technology is expected to become more commonplace after the FCC recently approved rules to facilitate its authorization and use.

Companies can quickly program SDRs - used at the base station to convert between wireless and landline transmissions - to transmit and receive on multiple frequencies in different formats. This reprogramming capability could alter how wireless users communicate and promote more efficient use of spectrum, according to the FCC.

In an SDR, functions that were formerly carried out solely in hardware - for example, the generation of the transmitted radio signal and the tuning of the received radio signal - are performed by software that is in high-speed digital signal processors. Because these functions are executed in software, the radio can be programmed to transmit and receive signals over a wide range of frequencies, as well as emulate virtually any desired transmission format. Simply changing the software can alter the operating parameters of such a radio.

The FCC made three recommendations:

l Create an official definition of SDR - a transmitter with operating parameters that can be altered via software changes.

l Adopt a "permission-to-change parameters" procedure. The current FCC approval procedure to change parameters is slow.

SDR technology enables a device's operating parameters to change more quickly, creating the need for a procedure that keeps pace with the speed of technology changes.

l Create an option for electronic labeling of equipment. Currently, if a manufacturer wants to make changes in the frequency, power or type of modulation for an approved transmitter, approval must be obtained, and the equipment must be re-labeled with a new identification number.

In a few weeks, the FCC is expected to ask for public comments about the recommendations.

SDR technology is becoming critical for cellular tower base stations because it enables them to handle a wide variety of current and coming technologies, said Lee Hamilton, president and CEO of AirNet,which has sold software-defined, wireless base stations since 1997.

With "hardware-defined" base stations, an owner wanting to upgrade or change service must replace all the base stations because they handle only a single wireless technology, Hamilton said.

Other base stations' capabilities can be altered with hardware changes, but most of these require "forklift-type" upgrades to handle coming technologies and to provide the scalability needed for the wireless infrastructure of the future, said John Ralston, chairman of the steering committee for the 110-member SDR Forum in Rome, N.Y.

"We need to make the base stations more powerful and efficient," Ralston said.

Companies such as Ericsson, Nortel Networks and Lucent Technologies that belong to the SDR Forum expect SDR to become commonly accepted throughout the industry during the next few years, Ralston said.

SDR also can improve wireless providers' bottom lines, Hamilton said. Specifically, hardware represents 80% to 90% of the cost of a new base station. By using an SDR base station, the wireless providers could save 70% to 80% on their capital expenditures, he said.

As the technology progresses and use of wireless devices increases, wireless providers will need base stations and other equipment that are quickly scalable to handle changing spectrum needs.

For example, there's a spectrum crunch during the business day in the heart of Seattle that creates numerous busy signals or noise on the line, said Ray Jodoin, an analyst for Cahners In-Stat Group. Once people leave their offices and start using wireless devices from their cars, that spectrum crunch moves to the outer ring of the city. An SDR base station would help manage those changing spectrum needs.

SDR also would allow wireless providers to juggle their spectrum needs more easily, Jodoin added. For example, AT&T Wireless currently provides customers with Ericsson handsets that can use three separate protocols - 800 and 1900 MHz TDMA and 800 MHz for analog overlay - so customers can make connections in a variety of locations. With the aid of SDR base stations, customers could use less expensive, single-protocol handsets because the base station would adjust the frequency as needed, Jodoin said.

Yipes Communications lit its Santa Clara, Calif., network, achieving its goal of opening 20 markets throughout the U.S. before the end of the year. Yipes will begin connecting businesses in Santa Clara to each other and the Internet at speeds up to 1 Gb/s.

Cannect Communications received approval from the Canadian Radio-Television and Telecommunications Commission to offer local switched services as a Canadian CLEC initially in the Vancouver, B.C. area.