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Wireless Networking Communications Networking Hardware Technology

Software-Defined Radio Could Unify Wireless World 113

Posted by Zonk from the cool-if-it-works dept.
mjdroner writes "Technicians in Ireland are testing a device capable of skipping between incompatible wireless standards by tweaking its underlying code. The article states: 'The device can impersonate a multitude of different wireless devices since it uses reconfigurable software to carry out the tasks normally performed by static hardware. The technology promises to let future gadgets jump between frequencies and standards that currently conflict. A cellphone could, for example, automatically detect and jump to a much faster Wi-Fi network when in a local hotspot.'"
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Software-Defined Radio Could Unify Wireless World More

Software-Defined Radio Could Unify Wireless World

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  • I've been researching similar technologies over the past few years because I believe we can see an amazing communications "utopia" by deregulating (or at least minimizing regulations) all the frequencies we're blocking for specific uses.

    Software radios are not new technology, but the implementation has been fairly worthless as frequencies are set up for specific purposes. At any given moment in any given area, there is a ton of bandwidth going unused. Frequency hopping is already pretty well documented in how to maximize its use, and power allocation specifications have been out since pre-cell phone days. Combine that with a much wider bandwidth and we can see higher data rates, lower battery usage and maximum bandwidth allocation everywhere you go.

    I know the FCC will never give up the bandwidth to the open market -- it is too lucrative for the few who are in cahoots with the licensing body. But I see so much happening just in the WiFi "unreglated" spectrum that I would really love to live in a world where all that analog TV, digital TV, analog radio, digital radio, CB, HAM and every other heavily regulated piece of spectrum could be allocated to being used for just information transmission. Software radios would set themselves to the best frequency possible to maximize transmission distance (as needed) and minimize power consumption (as needed).

    What we have now is more kludge than efficiency. Can you imagine how incredible the Internet would be if we had nearly infinite spectrum to use (compared to the limited spectrum we have now)?

    Sure, some people will say "What prevents Megacorp YYY from blasting 100,000 watts over every frequency?" That's pretty simple -- energy costs make it prohibitive to transmit anything but profitable data. The FCC has existed long past its useful life, maybe it is time to open up little bits of unregulated spectrum piece-by-piece and let's see what happens. These software radios are a huge step in the right direction.
    • Do you believe in faries too?

      Seriously, ou are right, the FCC isnt going to give up control of anything, as there is far too much $ to be made. Besides, when does a government give up control? ( unless of course its during a revolution )

    • Re:Software radios a step towards real deregulatio (Score:4, Insightful)

      by jcgf ( 688310 ) on Friday February 03, 2006 @06:25PM (#14638787)
      I think you need to remember that the RF spectrum is a finite resource and as such needs to be managed to prevent noise. Deregulate and you would have people lusing HF to go across town and I didn't pass the ham exams to have some bitch in kentucky's email to her boyfriend blocking DX when he lives down the street.
      • In software radio utopia the bitch down the street would have a software radio that would automatically range the boyfriend and select a band that allowed for the most efficient and localized transmission. Which I sincerely doubt would be your precious highly regulated HF band.

        In software radio utopia the radios would only invade low bit per second "buggy whip" HF bands when something like a category 5 Hurricane Zelda struck and knocked out the local high bandwidth high frequency ISP nodes.

        And even then a U
        • One huge issue I see with software radios is buggy software.

          The radio is going to need a very goof proof hardware enforced watch dog that will whip Microsoft's code back into line when it crashes and sits there spewing noise down the antenna.

          And even then I wouldn't be comfortable buying one with Microsoft code in it. The last thing I need is to come home to find the FBI waiting for me because my computer has been spewing junk into the VHF satellite rescue band.
        • Agreed, and "jcgf 688310"...too much caffeine?
          Get over the fact that the past does not always (sometimes,yes) translate to the future (or present for that matter).
          By your reasoning, I should be upset over the time I spent learning to chip/flake flint into arrowheads because some asshat came up with 'nukes.

          Get over it....use your ham exams until it pains you, then slap it between bread with cheese so you can enjoy a Ham and Cheese sandwich. ;)
      • "I think you need to remember that the RF spectrum is a finite resource and as such needs to be managed to prevent noise." LOL @ scarce resources. My technological utopia I live in will charge the RF spectrum with rainbows, sunbeams and pure human happiness. And if that fails I always have monkeys who shall deliver messages via unicorn. You crazy managers with your economic theories of scarcity.

    • But you have many problems to fix first... (Score:5, Insightful)

      by AB3A ( 192265 ) on Friday February 03, 2006 @06:25PM (#14638795) Homepage Journal
      First, how are you going to get the dynamic range you need for RF intense areas if the radio front end has to remain wide open for octaves?

      Second, energy costs for radiating Kilowatts are relatively cheap.

      Third, what about the near-far problems with spread spectrum?

      Fourth, how do you regulate narrowband emergency frequencies in a spread spectrum world?

      Fifth, if you're going to push everyone to unlicensed spread spectrum, how do we resolve interference disputes?

      I could go on, but I think you can figure out where I'm coming from. The problem is that if we didn't have radio and we were starting from scratch, you might be able to make a case for this technology. But since you clearly don't know how the standards got to where they are today you have no technical basis for trashing them.

      Keep dreaming until you get a clue...
      • Fifth, if you're going to push everyone to unlicensed spread spectrum, how do we resolve interference disputes?

        "Two men enter... one man leaves."
      • First, how are you going to get the dynamic range you need for RF intense areas if the radio front end has to remain wide open for octaves?

        Yeah! When I first read this post, I was thinking the same thing.
         
        Won't somebody please think of the octaves?
      • Yes, while the idea of SDRs to support multiple standards in a single band (or a small number of discrete bands) is easily feasible, and in fact is already put into practice in many cases, the fact is that obtaining wideband RF coverage without compromising performance is expensive at best, if not impossible.

        For example, the best noise figure I've seen for wideband MMIC preamps is on the order of 2-3 dB. Most such units have noise figures around 5 dB. I've seen narrowband preamps with noise figures less t
    • Sure, some people will say "What prevents Megacorp YYY from blasting 100,000 watts over every frequency?" That's pretty simple -- energy costs make it prohibitive to transmit anything but profitable data. The FCC has existed long past its useful life, maybe it is time to open up little bits of unregulated spectrum piece-by-piece and let's see what happens. These software radios are a huge step in the right direction.

      That's just nonsense. With no regulation at all, no frequency would be safe from a fly-by-ni
    • Sure, some people will say "What prevents Megacorp YYY from blasting 100,000 watts over every frequency?" That's pretty simple -- energy costs make it prohibitive to transmit anything but profitable data.

      No, it's not practical to blast 100,000 watts over ever frequency. I'm not worried about such a shot-gun approach. What I'm much more worried about is the "sniper" approach. Let's say that you're using the newly-deregulated spectrum to provide some service. Perhaps your trying to operate a local pub

    • I've been researching similar technologies over the past few years because I believe we can see an amazing communications "utopia" by deregulating (or at least minimizing regulations) all the frequencies we're blocking for specific uses.

      Same old anarchic anti-government trolls, huh dada21?

      At any given moment in any given area, there is a ton of bandwidth going unused.

      Yes, because of all the legacy equipment still in-use. You can't phase it out overnight can you? Everyone is bitching that the FCC is forcin

    • Cap max. wattage allowed & ban delbrt interfer (Score:2, Informative)

      by Anonymous Coward
      What prevents Megacorp YYY from blasting 100,000 watts over every frequency?

      Well miscreants may do it .. or well political groups may do it to silence broadcasts etc.

      It's better to simply ban intentional misuse and place a wattage cap for license free broadcast. Also open up more spectrum for WiFi and devices that are non parasitic (fine people who don't follow spread spectrum rules etc. if they are broadcasting above a certain wattage).

      I would really love to live in a world where all that analog TV, digita

    • Re:Software radios a step towards real deregulatio (Score:5, Insightful)

      by mesocyclone ( 80188 ) on Friday February 03, 2006 @08:01PM (#14639317) Homepage Journal
      I find it sad that the first post rated "Informative" is almost all political.

      Can't we look at this technology without the technology government bashing and utopian (and ignorant) libertarian rants?

      SDR is not a new technology, but it is rapidly becoming a good way to do things, as the hardware (digital and analog) to enable it is being designed and built.

      Cell phone companies are (or will soon be) using SDR to much more efficiently handle their multichannel cell sites. Instead of having a radio per conversation, or a radio per channel, they can have one or a few radios containing very high speed DSP SDR code. This saves cost and has the obvious flexibility of field upgradeability.

      GNU ( http://www.gnu.org/software/gnuradio/doc/exploring -gnuradio.html#software [gnu.org] ) has had an SDR project going for quite a while (I do wish they would do APCO P-25 reception, since I don't have the time). Hams have been doing various forms of SDR also - for example, the very narrowband systems that use a PC to do the DSP for HF data communications.

      Contrary to what some might think, SDR doesn't give magical powers to radios - the ability to operate on all frequencies at once. Radios have hardware filters in them for reasons that cannot be solved in software: to compensate for the non-linearities in the analog (or digital) software - which especially causes problems in high dynamic range situations. Radios may have to separate signals that differ in power by factors of 10^12 or more, which are relatively close in frequencies. Transmitters have to avoid emitting spurious signals at similar ratios to their output power.

      More specifically, if you put two signals (assume sine waves for now) into a non-linear device, it is the equivalent of putting those time-domain functions into a polynomial of degree 2 or more. This means that those sine waves will be multiplied by each other and themselves (and a coefficient which you try to make as small as possible). The result is output at the sum and difference frequencies and the harmonics of the original signals. Non-linearity can crop up in surprising ways. The most common one seen in radio is receive and transmit amplifiers, which are *always* non-linear. In addition, parasitic devices (such as two wires touching each other somewhere nearby) can act as non-linear mixers, generating spurious signals. Anyone who has worked on systems at crowded radio sites knows the fun of tracking down "intermod" signals (which are the result of this process). SDR's do nothing to improve this situation. On the contrary, they may require wider bandwidth amplifiers, which increases the odds of spurious signals. Furthermore, the very process of sampling with non-infinite bit-width A/D's and D/A's is itself a non-linear process that generates mixing.

      So SDR still has to deal with the issues at the antenna that analog radios deal with.

      Where it gets cool is at the baseband - in other words, at the modulation=baseband level (or in the case of multi-channel receivers/transmitters, at an intermediate level). This is where you take the information you want to send/receive, and convert it into/from the RF representation of that information. A simple example is FM modulation (used in most older land mobile radios - police, fire, cell phones, ham repeaters, etc, and in TV and FM radio broadcast). Here the SDR will take the modulation (voice or music or whatever), and use it to generate the signal equivalent to having it quickly alter the frequency of a carrier wave. Depending on the system, it may literally output a sine wave modulated this way. In other systems, it may generate some intermediate representation that then goes to the radio.

      But a far more interesting system might be a trunked narrow-band digital public service radio system (which US public safety organizations are converting to at FCC insistence). These systems are designed for improved flexibility (

      • I find it sad that the first post rated "Informative" is almost all political... "This is one place where the advantage of FDR appears." ... So let's discuss FDR in a more sane manner (if that is possible on the flamefest that Slashdot has bcome).

        FDR = Franklyn Delano Roosevelt = Liberal = one of the most politcally charged sets of initials in American politics.

        SDR = software defined radio = not really a question of politics

        a revealing lapsus??

      • I find it sad that the first post rated "Informative" is almost all political.

        Welcome to the new and improved slashdot.

        With the re-election of Bush jr we've seen that someone in the high ups of slashdot has a chip on their shoulder so anything that can be done with a political spin makes it to the front page and try to post an a-political post? Please. These vultures will find any crack in the sidewalk to take seed and make everything seem like it's somehow politically motivated.

        It's starting to suck ba

  • Software Defined Radios (Score:3, Insightful)

    by squidguy ( 846256 ) on Friday February 03, 2006 @06:05PM (#14638660)
    What's the big deal here? The US military and public safety sectors have been using radios with software defined waveform capability for over a decade. Expensive, but Moore's Law will drive the cost down to make devices using this technology commerically viable.

    • Here's the big deal (Score:4, Informative)

      by TubeSteak ( 669689 ) on Friday February 03, 2006 @06:15PM (#14638736) Journal
      The underlying technology has the potential to revolutionise wireless communications but has been difficult to test outside the laboratory until now as the majority of the radio spectrum has already been allocated. Licences are normally limited to a particular radio frequency and modulation but the one issued to CTVR permits a device to hop quickly between many different standards.

      The CTVR trial will also test how easily frequencies can be dynamically allocated to different devices. One idea is for companies that own a licence to automatically "sublet" access depending on demand. The licence [to trial the software radio] means we will be the first research centre in the world to practically investigate the commercial potential of dynamic spectrum-allocation,
    • Expensive, but Moore's Law will drive the cost down to make devices using this technology commerically viable.

      Arrgh... Thats not Moore's Law... Which is about transistors doubleing every 18 months or so, but you are thinking of Law of Accelerating Returns [wikipedia.org].
  • I've found it slightly puzzling that my wifi dongle's drivers don't make channels 12 and 13 accessible in 'US' mode, something I found out after my devices kept randomly switching from channel 13 to 11 every so often, despite the fact that I'd specified the channel my Wifi network is on. I realise there is an FCC restriction on those last two channels (in the UK 1-13 are perfectly legal) but it's always seemed totally arbitrary to me. Why has this decision been made?

  • Let's act before the next auction occurs... (Score:1, Insightful)

    by Anonymous Coward
    Before the FCC auctions off the analog TV spectrum for new proprietary, old technological uses (and filling the U.S. government's coffers), the technological community should educate the masses on why doing that could be a bad thing for new radio transimission/reception technologies.

    At least the FCC is recognizing some of the newer radio technologies, like Ultra Wideband, and conditionally approving their use (within specified spectral ranges).

  • antennas? (Score:3, Interesting)

    by adrianmonk ( 890071 ) on Friday February 03, 2006 @06:06PM (#14638671)

    I'm not much of a hardware person, so maybe I'm missing something, but aren't different types of antennas needed for different applications? Isn't the best size of antenna a function of its frequency? I understand how you can use software to replace some of the active circuitry, but how are you going to change the size and shape of an antenna via software?

    • Re:antennas? (Score:5, Informative)

      by SuperQ ( 431 ) * on Friday February 03, 2006 @06:32PM (#14638846) Homepage
      Antennas only affect the shape of the RF output, and the frequency range at which you can efficiently radiate.

      Take some examples:
      Omni-directional wifi antennas on most APs: a single stick with a fraction of the wavelength of 2.4ghz. Very simple, can do anything from SSB, AM, FM, or OFDM modulation.

      Most of what software defined radios is talking about modulation changes, not frequncy changes.

      The only difference between 802.11b and 802.11g is the modulation (CCK vs OFDM)
      • Antennas only affect the shape of the RF output, and the frequency range at which you can efficiently radiate.

        I wouldn't call that "only..." it's actually a big problem for UWB radios, where antennas need to be especially wideband.

        Most of what software defined radios is talking about modulation changes, not frequncy changes.

        I think that's because changing frequencies is really not hard; either you sample the whole spectrum and do everything in software, or switch between front ends. (I love to see a gigas
        • I love to see a gigasample per second ADC, that would be a thing to behold!

          You can already build a 1 GSa/s ADC with four AD9480's - however you'd need about 10 to 50 W of power to process the data. The power requirements for SDRs are often extreme, and that is the reason why they are not used everywhere. They are simply not needed in most of cost-constrained devices; and where they are needed they are used sparingly, processing only what must be processed.

        • you're correct on all counts, I was over-simplifying for the /. crowd.

          ahh.. the magic of a good HF multi-band vertical.. maybe not so much magic, but lots of coils :)

          1/4 is the fraction I was thinking about.
          • ahh.. the magic of a good HF multi-band vertical.. maybe not so much magic, but lots of coils :)

            Don't I wish... I was trying to put together an impedance matching network for a 802.11a antenna, figuring I'd just get some coils from Digikey. Unfortunately 1nH is way out of their ballpark :)

    • Comment removed based on user account deletion
    • but aren't different types of antennas needed for different applications? Isn't the best size of antenna a function of its frequency?

      from TFA:

      Although software-defined radio devices use a normal antenna and amplifier to receive a signal they are fundamentally different from conventional radio-based equipment. An analogue-to-digital converter changes the signal into a digital format, which can be then be processed and manipulated by the software.

      So from what i see in the above quotation, the stand

    • Re:antennas? (Score:2, Informative)

      by satguy ( 713646 )
      I understand how you can use software to replace some of the active circuitry, but how are you going to change the size and shape of an antenna via software?

      You don't necessarily need to change the size, you need to change the resonant frequency and impedance. This is currently done with 'automatic' antenna tuning circuits using varicaps and other components/switching circuitry that varies the resonant frequency by varying bias voltages.

    • I understand how you can use software to replace some of the active circuitry, but how are you going to change the size and shape of an antenna via software?

      Shape is nothing. You'll never strictly need a different shape of antenna.

      As for size, how do you think your TV antenna works? A VHF antenna is designed to cover all frequencies from 30MHz up to 300MHz.

      Basically all you need to effeciently cover the full range of frequencies effeciently is a balun (or "un-un") or an antenna tuner which could be softwa

  • The RF engineering crowd can enlighten us, but wasn't the idea of plasma antennas [plasmaantennas.com] kinda in the same vein? The idea being that the device could modify itself on the fly to have wireless ubiquity.

  • GNU Radio (Score:3, Informative)

    by mukund ( 163654 ) on Friday February 03, 2006 @06:07PM (#14638678) Homepage
    Perhaps GNU Radio [gnu.org] is of a worthy mention here.

  • The example you gave could kill free wifi. (Score:4, Insightful)

    by artifex2004 ( 766107 ) on Friday February 03, 2006 @06:08PM (#14638685) Journal
    Can you imagine what will happen when people find the free hotspots they're providing are constantly saturated by cell phone connections? At least until they firewall whatever protocol a phone would be using to wrap the equivalent of VoIP.

  • A plug for GNU Radio (Score:5, Informative)

    by InterruptDescriptorT ( 531083 ) on Friday February 03, 2006 @06:09PM (#14638692) Homepage
    Since we're talking about Software Defined Radio, I urge everyone with an interest in the subject to look at the GNU Radio project [gnu.org]. They have designed a front end board using generic cable TV tuners feeding an FPGA to perform some initial processing, such as decimation and filtering. The data is then transferred over USB to the host, whose software performs the demodulation and decoding. It's a fascinating project and a great stepping stone into the field.

    To really get started on SDR, check out the Ten-Tec RX320D [tentec.com] shortwave receiver. It outputs a 12 kHz-wide IF signal from the front end to an audio jack, which can then be fed to a PC soundcard. There are a number of packages that can take this data and demodulate it, including DREAM [sourceforge.net], an open source DRM (Digital Radio Mondiale) decoder which allows you to listen to the new digital shortwave transmission standard that many of the world's broadcasters are beginning to experiment with.

    • Re:A plug for GNU Radio (Score:5, Interesting)

      by evilviper ( 135110 ) on Friday February 03, 2006 @06:37PM (#14638875) Journal
      To really get started on SDR, check out the Ten-Tec RX320D shortwave receiver. It outputs a 12 kHz-wide IF signal from the front end to an audio jack, which can then be fed to a PC soundcard.

      Why spend that much ($350+), when you can order a dirt-cheap shortwave radio for maybe $40 and just use a simple 455 kHz to 12 kHz adaptor? [sourceforge.net]

      • Why spend that much ($350+)

        Because you would be supporting an American company that makes a good solid product. Besides, not everyone has the desire or ability to construct and/or install the downcoverters. I have the ability both build and install the converter, but I went with the RX320D on the strength of several reviews and construction quality. Sure I could have skimped and got a dirt-cheap shortwave receiver and hooked up the converter, but who knows how wide their IF stages are and the quality

        • Because you would be supporting an American company that makes a good solid product.

          Okay, then buy a dirt cheap, Made-in-China shortwave radio, with an American brand name on it.

          but who knows how wide their IF stages are

          Umm, everyone who can read the PDF... It's commonly published.

          and the quality of the construction?

          Again, buying a cheap shortwave radio doesn't preclude you from doing some basic research into the product before-hand.

      • Why spend that much ($350+), when you can order a dirt-cheap shortwave radio for maybe $40 and just use a simple 455 kHz to 12 kHz adaptor?

        SDR is a broad topic. Wide-band digital modes such as the 12KHz wide DRM or even narrow ones such as HamDream are a simple example.

        SDR involves a variety of techniques, but the basic idea is using an A/D at an early stage, and performing operations traditionally done with RF components with DSP software instead.

        In its extreme, an SDR has a broadband RF amplifier and a D

    • We've done some interesting stuff [pdx.edu] with USRPs. They're a lot of fun. With respect to the story about SDR wireless networking, check out our open-source 802.11 implementation for the USRPs. Early days yet, but we're making fairly rapid progress.

  • Great (Score:4, Funny)

    by TubeSteak ( 669689 ) on Friday February 03, 2006 @06:10PM (#14638707) Journal
    Once upon a time, it used to be that only the military could fark up my garage door opener.

    Now everybody will be able to.
    Thanks Ireland.

    • Re:Great (Score:3, Informative)

      by jc42 ( 318812 )
      [I]t used to be that only the military could fark up my garage door opener. Now everybody will be able to.

      Heh.

      However, to put it in perspective, we should note that this is directly in line with the original design, back when the Internet was called ARPAnet.

      The funding came entirely from the US Dept of Defense, and if you dig up the early ARPAnet docs, you'll find lots of diagrams of military scenarios, with everything communicating via wireless links. This makes sense, of course, because you really can't
      • Ideas have always run far far ahead of what science is capable of doing.

        Example: A Space Elevator. We've already worked out everything that would be required to create one, but we still don't have any material that's cheap & strong enough to pull it off.

        We could create an army with self-routing radio communications. But it'd be expensive as all hell.

        • Re:Great (Score:3, Insightful)

          by jc42 ( 318812 )
          We could create an army with self-routing radio communications. But it'd be expensive as all hell.

          It would only be expensive to develop. That requires a bunch of smart programmers who are willing to go against the commercial grain. But it's really just a SMoP (Small Matter of Programming. Once implemented, the hardware wouldn't be materially more expensive than the ad-hoc mess that is currently in use.

          The real barrier has been the same all along: Commercial suppliers have a strong incentive to try to blo

    • Re: (Score:3, Funny)

      by account_deleted ( 4530225 )
      Comment removed based on user account deletion
  • A cellphone could, for example, automatically detect and jump to a much faster Wi-Fi network when in a local hotspot.

    Hopefully, this will keep your calls connected more reliably than they do now, it will be interesting to see what happens next.

  • Ever wonder why your WIFI card needs firmware? (Score:4, Insightful)

    by gaijin_ ( 134592 ) on Friday February 03, 2006 @06:19PM (#14638760)
    It is because it is basically a software defined radio. You have a DPS and a set of AD/DA converters and a baseband (low freqency) to RF (high freqency) converter.

    Only difference here is that they are hacking the firmware for their Atheros wifi cards a bit more than the rest of us.
  • Look on this thread for a lot of naysaying, negative posts from supposed slashdotters, who would theoretically by anything but tech-luddites. But software radio could hurt a lot of established wealthy quasi-monopolies. So, they likely already have astroturfers posting on most big forums, setting up these issues.

    I read a metafilter post this week from someone who interviewed for such a job. THey were expected to post multiple times a day, and this marketing company had dozens of such astroturfers. I will try

  • Easy to see... (Score:3, Insightful)

    by rscrawford ( 311046 ) <{ude.sivadnu} {ta} {drofwarcsr}> on Friday February 03, 2006 @06:36PM (#14638872) Homepage Journal
    It's easy to see where this will go.

    1. They'll be successful, and the world will benefit from their tool.

    2. Some two-bit company from Podunk, Indiana, will claim that they have a patent on the technology. A lawsuit causes the court to issue an injunction against using software radio.

    3. Some other two-bit company from South Podunk, Iowa, files a suit claiming that software radio diminishes trade opportunities. The US government agrees and bans the technology. They try to get the EU to ban it as well, and a tussle ensues.

    4. Large corporations take over the technology and introduce a tiered system of access.

    5. Microsoft says they were planning it all along.

    In the end, no one benefits from the groundbreaking technology.

    Or, at least, that's how these things seem to be going these days.

    Did I mention the patent infringement lawsuit?

  • On the list of things that make me go hmm.... (Score:4, Funny)

    by Excelsior ( 164338 ) on Friday February 03, 2006 @06:54PM (#14638969)
    The technology promises to let future gadgets jump between frequencies and standards that currently conflict.

    So, in one fail swoop they've automated the radio dial and the AM/FM button? Science rocks.

  • Power consumption (Score:2, Interesting)

    by s!mon ( 15429 )
    It would be nice except Slashdot has been posting something about software radio for years and still nothing. Other factors to consider:

    1) Power consumption on software radios will be much less efficient than their analog counterparts
    2) band limited to certain frequencies - relevant because higher powered transistors at higher frequencies are becoming available, pushing beyond the 2.5 GHz limit we have right now (compliments of Gallium Nitride and Gallium Arsenide).

  • Why on Earth would the cellular companies ever sell you such a device, or allow one on their networks? Sure, it's a pretty idea, but the gatekeepers of the big wireless networks will have none of this.

  • Cognitive radio-SDR (Score:3, Interesting)

    by slashdotmsiriv ( 922939 ) on Friday February 03, 2006 @07:30PM (#14639158)
    Cognitive radio is a concept very related to this discussion. I googled a little about SDR and cognitive radio and came across some interesting paragraphs. Short Definition of SDR: Software defined radios are making it possible to change waveform properties and applications while operating in the field via the addition or upgrade of software. For SDRs, reprogramming or upgrading a single radio or a radio network takes about as much effort as upgrading a computer's operating system or program options. US Army interest : For its part, the U.S. Navy is likely to be the largest consumer of software defined radios with the military's Joint Tactical Radio System Initiative (JTRS) radios following closely behind. For the Navy, the software-based Digital Modular Radio (DMR) is replacing a roomful of radios with a single rack of DMRs. The DMR is a four-channel, full-duplex system that is essentially four radios in one. Currently operating on submarines and surface ships around the world, the DMR (AN/USC-61) is successfully demonstrating the viability of software defined radios on active duty. Cognitive radio: The cognitive radio, as its name implies, builds on Software-defined radio to carry a level of cognition or intelligence that permits decision-making and learned patterns of behavior. According to IEEE, the cognitive radio is a radio transmitter/receiver that is designed to intelligently detect whether a particular segment of the radio spectrum is currently in use and to jump into (or out of) the temporarily-unused spectrum very rapidly without interfering with the transmissions of other users.

  • Ths is old technology in cell sites (Score:3, Interesting)

    by Animats ( 122034 ) on Friday February 03, 2006 @07:34PM (#14639190) Homepage
    Cell sites have used software-defined radios for many years. Cell sites today have far fewer discrite radios than they have active channels. Here's a typical software defined cell site radio system. [airnetcom.com]

    This isn't all that new. It's just becoming cheap enough that it's worth doing for single-channel units.

  • A winmodemish wireless network card.

  • Joint Tactical Radio System (Score:2, Interesting)

    by Anonymous Coward
    For some really interesting reading on software defined radios, do some research on the DoD's program called Joint Tacticle Radio System (JTRS). The goal is to replace ALL radio's in the DOD and other government agencies (think police, fire, ems, homeland defense, fema, etc as well as coalition countries) with a JTRS radio (in a few different form factors) using standard waveforms that are kept in a single library to ensure compatibility. The basic chasises will use pluggable modules for both "standard" w
  • I want a software-tuned phased-array. That's my idea of a universal radio: any frequency, all frequencies, multiplied by all the points from which transmissions originate, across several GHz of spectrum, suited to a mobile device. Finally bandwidth to compete with a stationwagon loaded with backup tapes.
    • Finally bandwidth to compete with a stationwagon loaded with backup tapes.

      Hah, the problem is that I can put one of your universal radios on the van, get close to the sender, load up, drive to receiver, and unload. For a big enough distance with a large near/far radio capacity ratio the van always wins :)

  • You assume I'd want to go WiFi (Score:3, Interesting)

    by scotty1024 ( 584849 ) on Friday February 03, 2006 @09:44PM (#14639759)
    Here in Seattle I've often found my Verizon EVDO is faster than T-Mobile's Starbucks or Border's WiFi hot spots.

    And what if I'm on the bus traveling down the street: 3G, WiFi, 2.5G, WiFi...

    The decision to switch from 3G to WiFi will have to be made on more complex criteria than simply "Oh look WiFi!!"

    Right now my Tablet PC can't even handle going "Hey Wifi!" reliably, although Mac's do it quite well.

    And I can't even begin to picture how one would handle a TCP hand off with out using IPv6. RIght now Verizon and CIngular both suck at handing off seamlessly from 3G to 2.5G and back to 3G when running around in a bus on their own networks (where they have control over IP addresses' and routing).

    I submit that these issues push things further out than you think to achieve your utopia.
  • As the Esperantinos would say: Bonvolu alsendi la pordiston? Lausajne estas rano en mia bideo!
  • I actually worked on a literal all-band/all-access (look up access in a Communications textbook) communications system once.

    But it was 1985, and it was all in hardware.

    It was basically a mobile shelter containing every kind of radio you've ever heard of, your local ham club has ever heard of, your local military base has ever heard of, and one or two nobody has heard of.

    Right after that I went into software and haven't looked back.

    So the world is 20 years behind me. Explains a lot.
  • Well, there goes my terrestial HDTV due to RF polution.
  • Intel's WLAN solution used in Centrino laptops, namely the ABG-compliant mini-PCI card has the ability to send and receive in frequencies from 600MHz to 7.2GHz with up to 500mW transmit power.

    However, the open source drivers for Linux are deliberately crippled to very low transmit power (32mW) and narrow frequency bands by forcing Linux users to download and install a closed binary part. This closed DRM part is NOT present in Windows drivers and there exists at least two (albeit very expensive) programs tha
  • Too smart to be really used by industry.
    Infact manufacturers would then have fewer ways to convince customer to buy newer and better devices as a replacement of the older ones.
  • Could you stop using such big words you assholes?

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