Federal regulators figure that eliminating incompatible wireless standards might span the digital divide—or at least span the bridge from second to third generation wireless gear.

by Roy Mark of dc.internet.com news [September 14, 2001]

The Federal Communications Commission this week adopted rule changes to accommodate the authorization and deployment of a new generation of radio equipment known as software-defined radios (SDRs). The new rules allow manufacturers and operators to reconfigure devices after they have been deployed in the field.

This reprogramming capability could change the way users traditionally communicate across wireless services. In a software-defined radio, functions that were formerly carried out solely in hardware, such as 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.

Street-smart
Because these functions are carried out in software, the radio is programmable, allowing it to transmit and receive over a wide range of frequencies and to emulate virtually any desired transmission format. The operating parameters of such a radio can be readily altered by a simple software change. SDR concepts span all types of wireless handhelds from cellular phones to feature phones, smart phones, PDAs, computing devices and smart antennas.

The most prominent and immediate area of adoption is in the communications field. Today's digital cellular and PCS networks use a variety of second-generation (2G) or what's come to be known as 2G.5, digital technologies for the air interface link connecting terminals and networks. These links currently embrace a number of standards wireless standards, including GPRS, HSCSD, among others, and are based on different protocols such as WAP, pJAVA, compact_html, and the like, for accessing the Internet. The divergent 2G standards, already adopted by large groups of end-users around the globe, often frustrate business travelers who communicate with their customers or offices while traveling from one network type to another because they cannot use the same device without significant enhancements or adjustments. The FCC rule change attempts to deal with making incompatible systems work together.

Untangled airwaves
Adding to the complexity, the wireless industry is in the throes of migrating to next generations of these very same standards and protocols, as well as introducing new technologies such as GPS for location services and Bluetooth for local communications. With SDR, one would implement a common hardware platform and accommodate these standards and technologies via software modules and firmware.

In March 2000, the FCC released a Notice of Inquiry seeking comments on a number of issues related to software-defined radios. These issues included the current state of technology, how this technology could facilitate interoperability between radio services, how it could improve the efficiency of spectrum use, and what changes may be required in the FCC equipment approval process.

Under the former rules, if a manufacturer wanted to make changes to the frequency, power or type of modulation for an approved transmitter, a new approval had to be obtained, and the equipment had to re-label the device with a new identification number. These requirements had not posed problems in the past because radio transmitters have not had the capacity to change operating parameters in the field.

Under the rules adopted this week, software modifications in an SDR can be made through a "permissive change," which has a streamlined filing process. The FCC identification number will not have to be changed so equipment in the field will not have to be relabeled. Permissive changes can be obtained only by the original grantee of the equipment authorization.

Sanctioned e-labels
To allow for changes to equipment by software developers, the FCC will permit an optional "electronic label" for SDRs that would permit the FCC identification number to be displayed on an LCD or similar type screen. The rule allows for a third party to obtain an equipment approval in its own name and become the party responsible for compliance instead of the original equipment maker.

The SDR Forum is an international industry association dedicated to supporting the development and deployment of software defined radio systems that enable flexible and adaptable architectures in advanced wireless systems. Naturally, the groups chairman was pleased with the FCC's actions.

"We are pleased that the FCC is proceeding with such diligence on SDR issues,'' said Stephen Blust, chairman of the SDR Forum. "As a technology that enables wireless operators to update their networks or phones to accommodate new standards, SDR is at the forefront of enabling a seamless worldwide wireless network.''

Membership of the SDR Forum spans commercial, defense, and civil government organizations, and includes wireless service providers, network operators, component and equipment manufacturers, hardware and software developers, regulatory agencies, and academia.

Whether the new rules will spur the development of 3G wireless broadband deployment remains to be seen. But consumers will need fewer devices to connect with high-speed wire-free systems in the near future, as SDR units come to market.

— End