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Civilians, military seek different kinds of Software-Defined Radio

From "SDR goes to war" by Nicholas Cravotta, EDN, 14 September:

"SDR (software-defined radio) is not a new technology. The industry has in the past made attempts to implement SDR, but these efforts have fallen short. What has sparked recent interest in SDR is the rise of innovative hardware and software technology that appears to offer enough flexibility, performance, and power efficiency at a price the market can bear.

"For example, wideband converters are now available that operate over a wide range of frequencies and can process incoming waveforms based on a specific bit resolution, and high-frequency processors can work with signals directly, eliminating IF (intermediate-frequency) stages and reducing cost.

"The appeal of SDR stems from an understanding that moving to a single hardware platform that can handle multiple radio technologies will not, as you might expect, cost more than individual radio designs that target the lowest cost for an application. The hope is that a versatile platform will introduce significant economies of scale, increase radio functions, and release the military from the bondage of proprietary implementations. The cost efficiency of SDR derives from the premise that maintaining a single radio platform is less expensive than managing multiple platforms... The drive behind SDR in both military and commercial applications is to reduce cost.

"The military seeks to achieve this goal by attempting to reduce the total number of radios that an individual must carry. From a commercial perspective, SDR focuses less on supporting multiple radio technologies than it does on reducing design and development effort, increasing radio robustness through comprehensive upgrades, and enabling next-generation architectures to reuse [intellectual property] by building on previous implementations.

"Currently, the military wants to support more than 30 protocols... Driving the promotion and advancement of SDR for military applications is the JTRS (Joint Tactical Radio System). The JTRS' SDR efforts aim to promote the availability of off-the-shelf hardware and software components that enable a single implementation to handle multiple protocols' waveforms...

"The ability to support multiple protocols holds less value in the commercial world than in the military world. Often, less than a handful of protocols is competing within [a civilian] application space... These perspectives significantly alter how these industries have approached SDR. For example, a world phone that can operate on any band would have limited usefulness and an even smaller market share. The military seeks consolidation, whereas the commercial world seeks design simplification...

SDR's promise

"The ultimate goal of SDR is to create a radio in which frequency, IF, baseband, modulation, protocols, hopping frequency, and so on are programmable. A typical radio implementation fixes many of these characteristics, limiting the radio. True SDR strives to make it possible to modify any of these parameters.

"Current implementations of SDR are still a long way from the ideal universal radio that marketing managers envision... Generic front ends covering multiple bands and frequencies that you could modify using software are still not here. Rather, operators must either send the radios back to the factory... or, more appealing to those in the field, swap out an RF module on their own...

"A fully dynamic and reconfigurable radio offers many benefits besides support of multiple bands. For example, a radio could use FEC (forward-error-correction) techniques to match the terrain in which the radio is operating. Additionally, reconfigurable radios can immediately take advantage of innovation, such as a more efficient waveform implementation or a [more] robust security mechanism.

"SDR also promises to minimize development time... For example, although protocols themselves may stay static, algorithms, waveforms, and modulation schemes continue to improve over time. With an SDR-based architecture, you can take advantage of these improvements and innovations without redesigning the radio.

The SCA framework

"The keystone of the JTRS' mandate to promote SDR in military applications is the SCA (Software Communications Architecture) framework. The JTRS is developing this framework to break the link between hardware and software, which in turn will break the hold that proprietary implementations have on the military... The goal is that any SCA-compliant waveform will operate on any SCA-compliant radio hardware...

"Today's SCA framework supports portability of waveforms a few steps shy of the transparent interoperability developers are seeking... The SCA effectively addresses portability for general-purpose processors, but it clearly misses the mark where specialized hardware is concerned... This problem is difficult to solve. The most efficient code matches the architecture in use... [A] single generic implementation doesn't seem effective... General-purpose processors are effective at efficiently implementing generalized tasks but are much less efficient than specialized hardware at implementing well-defined, computationally intensive processing algorithms, leading to greater power consumption and larger radio form factors - both undesirable results. The JTRS is seeking to leverage the advantages of specialized hardware without tying software to proprietary hardware implementations.

"Getting SDR to the point at which radios are no longer proprietary platforms is a high priority for the military... even if some military-radio suppliers are unenthusiastic about the prospect of widening their narrow playing fields to outside competition. SCA is the foundation of this reality.

"In the commercial world, however, the SCA framework has a limited hold and perhaps even less appeal... Completely interchangeable hardware and software leads to a market in which the only differentiation is cost. There are few advantages to opening designs in the commercial world simply to invite competition that will drive down profit margins. The commercial world thrives on innovation, and, in radio applications, hardware is a key differentiator. As it stands, the SCA framework inhibits the introduction of specialized hardware...

"The military is pursuing the ideal of total interoperability and interchangeability. The commercial world strives to balance efficiency, function, and cost. With such diverse goals and applications, it's almost as if they're dealing with two disparate technologies."

[SDR: 19 September 2006]