Signal Processing DesignLine Blog
The quiet SDR revolution
Kenton Williston
3/2/2009 12:00 PM EST
Each of these announcements is quite impressive, but put them all together and I conclude that SDR has become a mainstream technology. I ran this idea past industry experts like Will Strauss of Forward Concepts and Jeff Bier of BDTI, and they disagreed with me. To them, SDR still has a way to go before it can be considered mainstream.
So what gives? Am I drawing the wrong conclusions, or has the age of SDR has arrived without anybody noticing?
To answer that question, we first need to define SDR. The SDR Forum defines it as "Radio in which some or all of the physical layer functions are software defined." That's a very broad definition. Under this definition, you could argue that every handset modem on the market is a software-defined radio—and in fact the SDR Forum sees the world this way. This seems like a silly argument to me. If every radio is a software-defined radio, then what is so special about SDR?
On the other extreme, some people think of SDR as a system where the entire signal chain is done in software. (You still need an analog front-end, of course). This sort of system is not practical for commercial applications, and is unlikely to become practical any time soon. That's one reason Jeff Bier and Will Strauss disagreed with me—if this is what you mean by SDR, then SDR is obviously not mainstream.
My own idea of SDR lies somewhere between these extremes. I like the Wikipedia definition: "…a radio communication system where components that have typically been implemented in hardware (e.g. mixers, filters, amplifiers, modulators/demodulators, detectors. etc.) are instead implemented using software." By this definition, the CEVA, Octasic and Imagination platforms all qualify as SDR. All three of these platforms do things in software that were previously done in hardware.
If you can accept this middle-of-the-road, somewhat fuzzy definition of SDR, you can make the case that SDR has become a mainstream technology. So, I'll stick to this view, even after talking to Jeff Bier and Will Strauss. What do you think?
Next time: I explain how changes in technology and market forces have aligned to bring SDR to a tipping point of mass adoption.
PS—I am excited to announce a HUGE discount on the Embedded Systems Conference. We've dropped the prices 25% for DSP DesignLine readers. That's a savings of up to $400! Use code CTMSP15 when you register online.
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anindya
3/3/2009 4:52 AM EST
Agree with you, a lot of things are seeming to go the SDR way. Please check out the following website of Saankhyalabs which is building a universal demodulator for DTV/ATV platform based on SDR approach.
http://www.saankhyalabs.com/index.html
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Lee Pucker
3/3/2009 6:27 PM EST
Kenton, I think you are exactly right - the benefits of SDR to date have largely been realized by radio manufacturers, allowing a family of radio âproductsâ to be implemented using a common platform architecture, allowing new products to be more quickly introduced into the market, and allowing "bug fixes" to occur while a radio is in service, reducing the time and costs associated with operation and maintenance.
In the near term, these benefits are being extended to radio service providers, allowing the use of a common radio platform in multiple markets, significantly reducing logistical support and operating expenditures. It also allows new features and capabilities to be added to existing infrastructure without requiring major new capital expenditures, protecting service providers from changes that may occur in wireless standards from time to time and allowing them to quasi-future proof their networks.
This evolution will continue overtime, reducing the costs associated with providing end-users access to ubiquitous wireless communications â enabling them to communicate with whomever they need, whenever they need to and in whatever manner is appropriate. Fostering this evolution is one of the key roles of the SDR Forum, helping our 108 member organizations to shepherd the migration of the technology from the simple case you present above to the case where most of the signal chain is actually implemented in software. Most systems today, as you say, are somewhere in the middle, but I think everyone will agree that the percentage of software is going up, enabled by breakthroughs in technology and by Mooreâs law.
Lee Pucker, CEO, The SDR Forum (www.sdrforum.org)
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martinm_de
3/4/2009 4:41 AM EST
Why not make things simple:
SDR is meant to be configurable via a change in software to adapt to different wireless standards: my GSM phone in Europe could be adapted to the Japanese standard by simply downloading some piece of software.
Hardware like a fractional PLL and the mixer to downconvert the signal to the IF, the ADC to convert the analog to digital can easily be re-configured by software.
Hardware like viterbi decoder and other stuff which follows in the signal behind the ADC chain may be harder (if impossible) to re-configure via software to implement completely different decoding schemes for different wireless standards: the processing power needed is so huge that power consumption requirements imply a need for ADICs to bring power down.
One could think about re-configurable FPGAs to implement digital signal procesing algorithms using less power than the 'obvious' DSPs.
All in all, software defined radio requires lots of efforts by the hardware vendor.
And who, finally, benefits from SDR?
I think this is the real question.
As a consumer of various wireless products,
I only see a potential benefit: my computer has a WLAn and a bluetooth interface. I never want to use them simultaneously, so, an SDR could be of use here
The amount of money saved here is probably EUR 5. It this really worth it?
The mesing around with software, the potential instability, etc?
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3/9/2009 2:04 AM EDT
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nasdy
3/9/2009 2:05 AM EDT
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