Sep
25
Written by:
Jason Shannon
9/25/2008 1:24 PM
In the fall of 1964, inventor and physicist Robert Moog displayed a prototype of a subtractive synthesizer at the Audio Engineering Society Convention in New York. This experimental musical instrument worked via “Voltage-Controlled Electronic Music Modules”, as Moog explained in journals during that time. At first glance, this device didn’t seem practical for the typical musician and was viewed mostly as a curiosity by spectators at the AES Convention. The Moog synthesizer was monophonic, meaning that only a single key could be played at a time. In addition, it required hours of meddling with complicated electronic circuitry to adjust the sound. Few would have guessed that despite its inherent limitations and its difficult usability that this strange keyboard instrument would eventually grow to disrupt the market of the traditional piano. This disruption occurred due to the evolution of the integrated circuit, transistor and the impact of Moore’s Law. Today, “software instrument modules” can be downloaded for nearly any sound imaginable from the Internet. With a click of a mouse, a musician may summon the Passau Pipe Organ from Saint Stephens Cathedral, or, in the next instance, a Steinway 1902 Model “O” Grand Piano. The possibilities of software defined musical instruments are limitless. It makes sense that the sale of traditional pianos dropped sharply through the 80’s and 90’s, putting many traditional manufacturers out of business while the digital synthesizer manufacturers thrived.
EARLY MOOG SYNTHESIZER, 1964
In the example above, the effect of disruptive innovation driven by Moore’s Law revolutionized the music industry and disrupted the market for the traditional piano. The wireless broadband industry is on the verge of a similar such revolution with the dawn of the Software-Defined Radio (SDR). If a musician can summon a $50,000 Grand Piano on a $500 laptop, could it also be possible to summon a $50,000 WiMAX base station on a $500 modular computing platform? The answer is yes, and it has astounding implications for wireless broadband.
At its basic level, Software-Define Radio is the virtualization of the physical hardware components of a radio system within software. The exceptions to this virtualization is the A/D front-end and the antenna, which are required to physically produce the electromagnetic radio signal, much the same way that a sound card and speaker is required to physically project the sound waves of the software-defined grand piano in the previous example.
There are significant advantages to SDR beyond price. Imagine if a cellular base station could broadcast a WIMAX signal during one time-slot, broadcast an LTE signal during another time-slot, and broadcast a Personal / Portable White Space signal during another time-slot. This is possible within software, but would create a very difficult design challenge using traditional hardware based radio modules. Such a system would require an extremely complex mechanism to coordinate between physical hardware components. In addition, such a system would be very expensive and have a very large physical footprint. SDR is not limited by the constraints specific to dedicated hardware. To understand this point, think about what the world would be like if modern computing developed in such a way that a computer was single purpose and you needed separate machines to access email, the Internet, and other dedicated applications. The very notion of adding a dedicated device for every new application is foreign in the computer age, where the theoretical concepts of computer science and software developed by Turing and other pioneers are thoroughly ingrained in our thinking. In the example above, the fundamental concept of software has been applied to that of a cellular base station.
Software radios allow systems to be adaptive and intelligent and aware of the environment. What if an SDR base station could dynamically enable and disable software modules such as WIMAX, LTE and White Space based on cognition of the user base at any given moment in time? What if the base station could download operating firmware from client devices when these new devices enter the cell? What are the implications for femto / pico cell and municipal wireless networks? SDR introduces a paradigm in the way radios divide frequency, space and time and adapt to the environment. In a world where the regulated airwaves are so heavily constrained, SDR offers an efficient and self-optimized means of converging a diverse and transforming user base.
ETTUS RESEARCH USRPv2 SOFTWARE-DEFINED RADIO, 2008
It will be fascinating to witness Software-Defined Radio systems move out from behind the lab bench and into practical broadband and telecommunications applications. Moore’s Law will continue to drive technical capabilities while lowering economics of hardware and Open Source will continue to drive technical capabilities while lowering economics of software. We are on the verge of a substantial revolution as these forces intersect and change our perception of wireless broadband. Will current base station and pico cell access point manufacturers embrace these forces, or will they suffer the same fate as the traditional piano manufacturers in the 80's and 90's? Perhaps pianos and wireless broadband have more in common than we think.
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