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Wireless Networking Software Hardware

Vanu Replacing Cell Tower Equipment With PCs 202

Posted by timothy from the folgers-commodity-software-crystals dept.
Dwight Schwartz writes "As reported in an article on the ScienceDaily site, researchers from Vanu, Inc. of Cambridge, MA, have successfully tested a system, the Vanu Software Radio(tm), that can replace a cellular tower's room full of communications hardware with a Pentium-based computer running Linux. The system offers the hope of making cellular technology more affordable for small, rural communities." The systems have been tested for the last several months in parts of Texas, with wider adoption planned for the near future.
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Vanu Replacing Cell Tower Equipment With PCs More

Vanu Replacing Cell Tower Equipment With PCs

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  • Finally. (Score:3, Funny)

    by digitalunity ( 19107 ) <digitalunityNO@SPAMyahoo.com> on Wednesday October 08, 2003 @03:48AM (#7161144) Homepage
    This is actually *newsworthy*. I was starting to have withdrawls.

    This should have a big impact on small towns where expensive cellular equipment isn't cost effective.

  • Affordability for rural people! (Score:5, Interesting)

    by commie_pig ( 585693 ) on Wednesday October 08, 2003 @03:51AM (#7161150) Homepage

    This is excellent. I live in South Africa, and there is a massive gulf between the poor and the few rich - this will help to connect all the poor people, and especially the ones in rural areas.

    What makes me the happiest of all, is that the system runs Linux, and this is great in the light of the fact that the South African government has articulated its commitment to open source software (they have indicated that they may replace several government systems with Linux boxes! so I hope that it happenes)

    It just shows what a bit of ingenuity can do.

  • shed some light? (Score:3, Interesting)

    by mOoZik ( 698544 ) on Wednesday October 08, 2003 @03:51AM (#7161151) Homepage
    How can a single Pentium-based computer handle the bandwidth of many simultaneous calls? Does it merely act as a router or as something more? I ask because the article wasn't clear.

    • Re:shed some light? (Score:5, Informative)

      by Gordonjcp ( 186804 ) on Wednesday October 08, 2003 @04:06AM (#7161194) Homepage
      How can a single Pentium-based computer handle the bandwidth of many simultaneous TCP/IP connections?


      GSM is pretty low-bandwidth stuff (around 13kbps). Further, the line cards handle a lot of the framing and general cookery for the interconnects (whether it's a wired E1, or microwave, or whatever). So even a fairly low-end Pentium would handle a few calls. The article does say that it needs a fairly large Linux server, but an ordinary PC would work for a relatively small node. The Digitalk telephone switches we use are really just dual PII-500 machines, and they handle 120 simultaneous wired calls.

      • Re:shed some light? (Score:5, Interesting)

        by silentbozo ( 542534 ) on Wednesday October 08, 2003 @04:14AM (#7161221) Journal
        So the linux boxes are cheap. What about the interconnect equipment? Can a guy off the street spend a few hundred and build his own phone network, or is the marginal cost still significant?

        Hell, if it's cheap enough, I'll start my own wireless phone company :)

        • Re:shed some light? (Score:3, Interesting)

          by Gordonjcp ( 186804 )
          Don't know about wireless kit (probably many thousands) but E1 cards are a few hundred quid and usually provide 30 voice channels per E1, of which there may be two or four on the board.

          It would be nice to get your own celltower, but your range would be pretty limited. You'd need one for every few square miles. I wonder if there'd be anything to stop you setting up your own cell tower in a dead spot, and letting people roam to it? We hardly ever use roaming any more in the UK, since nearly everywhere is
        • Nope, John Q. Public can't use this to create his own cell phone company, no way he'd be able to afford the license to use the GSM frequencies...

          And the key "battery not included" in this problem is also that this thing is going to need some link longer-range than itself to get back to the main PTSN, otherwise you can only call other users on the same micronode and that's likely pointless because they'll all be able to hear you shout too.

          So really, the main use of such a device will be to fill in small bl
          • Imagine your own picocell, inside your house.
            Now your cell is your wireless, and you can use
            it with your IP telephony service. Likewise when
            visitors come to your house, their calls can be
            routed over IP.

            Imagine everyone has picocells. Now you don't use
            cell minutes, you don't pay line charges, you just
            communicate at will, whenever you're in range.

        • Re:shed some light? (Score:4, Informative)

          by Mattcelt ( 454751 ) on Wednesday October 08, 2003 @07:06AM (#7161680)
          Incremental repeaters are already available. They must be low enough power to fall beneath the regulated power levels of the FCC, generally not more than 4-5 watts, I think.

          aceteq.com [aceteq.com] has some good repeaters, even the 1900 mhz repeaters for US GSM for less than $800. Other systems can be $3000 or more, and can cover larger areas (I've seen some that were capable of 25,000 sq ft.)

          So you would have to do a running line of small repeaters to get service to an area, similar to the 802.11 repeaters we've seen here. You might be able to convert it to line-of-sight and do it that way, too.

          But the short of it is, it can be done, albeit somewhat expensively.
        • Can a guy off the street spend a few hundred and build his own phone network, or is the marginal cost still significant?

          The hardware itself is not particularly expensive. Commercial cellular equipment are costly because they tend to be custom hardware with limited production runs. They are also subject to very high reliability requirements (a few hours of downtime per year), and have hardware-level redundancy. If you relax those requirements, an PC with appropriate I/O hardware (even better, additional

    • Re:shed some light? (Score:4, Interesting)

      by Anonymous Coward on Wednesday October 08, 2003 @04:14AM (#7161220)
      The article seems to basically be saying "we've reduced the amount of kit you need to run a cell" - I'm sure it just removes a tiny portion of the kit needed to set one up though. The article mentions that previously emergency and public calls used separate kit, and that this system uses a PC instead.

      So, my bets are: it's replacing a bunch of routers by becoming a software-based router itself, and doesn't handle calls, but merely switches between networks based on call type. All of the other equipment in the cell will still be required. So in essence it reduces the cost, but by no means reduces a cell node to one PC with an aerial sticking out of it.

    • Re:shed some light? (Score:2, Informative)

      by Entrope ( 68843 )
      Bandwidth and routing functions are not problems -- the radio function is the problem. Traditionally, decoding the modulated signal (finding the carrier and recovering likely bits) was done in dedicated hardware. Sometimes, Viterbi or other maximum-likelihood decoding is also done in hardware. WIth current PCs -- especially with SIMD instructions like the SSE family -- the demodulation function can be implemented mostly in software.

      The practical effect is that instead of having a (hardware) platform tha
    • Remember that reporters rarely know much about technology. To them, everything is a "Pentium," including the monitor. These are probably P4/2.0GHz or at least a high-end P-III, not an i586-generation machine running at 120MHz.
  • Loads of great ideas that are going to change the world and it's not going to cost barely anything!

    It's like 1998 all over again!

  • The original article (Score:5, Informative)

    by jonbrewer ( 11894 ) * on Wednesday October 08, 2003 @03:52AM (#7161156) Homepage
    Have a look at the original release [nsf.gov] from the US National Science Foundation. With some nice pictures [nsf.gov]. :-)

    • Re:The original article (Score:2, Insightful)

      by Anonymous Coward
      Bloody hell! Are you guys in the US still running analog mobile services?

      Seriously, we've been installing digital nodes in the UK for years now with the kind of 'new' setup that you can see in the parent's picture. The old brown stuff looks like the kit I was ripping out back in 1997 - clunky old analog cell switches. So as well as reducing the kit costs, the services are also being switched over to digital as well? In that case, the size/kit reduction is a given, and this is nothing special.

      If we're talk
      • Only the most rural areas have exclusively analog service; everywhere else is covered by at least one digital provider. Most of the interstate highways (and adjacent cities) are covered by a couple digital providers.

      • Bloody hell! Are you guys in the US still running analog mobile services?

        Yes, in the sort of areas that have similar population densities to Scotland's non-served cell areas (and to be fair, some parts of Scotland that get lots of tourists but still have low population density do have digital cell coverage while in the USA areas there are few areas like that...there are also places in Scotland that have digital coverage while the equivalent part of the USA has analog only, but on the whole I would say

      • From http://www.telemetric.net/pdfs/analog-digital.pdf [telemetric.net]

        In February of 2003, the FCC modified Part 22 of its rule that covers cellular telephones and other services. Among the rule changes adopted by the commission is the amendment of sections 22.901 and 22.933, governing support of AMPS. These documents can be found at http://www.fcc.gov/. In effect, the ruling states that cellular carriers must provide analog service compatible with the AMPS specification for at least the next 5 years. The FCC has pro

      • While I appreciate that the US may be huge and need these kind of things for rural communities

        Oregon alone (96,000 sq. mi.) is bigger than the United Kingdom (94,525 sq. mi.), but has 1/15th the population.

  • room full of communications hardware (Score:3, Insightful)

    by faldore ( 221970 ) on Wednesday October 08, 2003 @03:59AM (#7161175)
    But is the PC as reliable as a room full of communications hardware? I think not. As soon as your Hard Drive goes out 911 is out of commission.

    • Re:room full of communications hardware (Score:5, Insightful)

      by vidarh ( 309115 ) <vidar@hokstad.com> on Wednesday October 08, 2003 @04:10AM (#7161213) Homepage Journal
      Why do you assume the PC wouldn't be a hardened rack unit targetted for industrial use? And why do you assume it won't have a solid state storage device instead of a hard disk? And why do you assume it won't be highly redundant? And why, even though the system COULD run on one PC do you assume there won't be an extra machine there for failover? And why do you assume the towers will be so far apart that service will be entirely lost and not just degraded if a PC fails?

      Assuming using a PC can't give redundancy and resilience against failures is extremely presumptious. But for areas that currently don't have ANY coverage, even a desktop PC powered base station would be an improvement.

      • And why do you assume the towers will be so far apart that service will be entirely lost and not just degraded if a PC fails?

        Because according to the article (as well as the writeup for this topic), they are targeted for rural communities, wehere by definition the towers will be so far apart that service will be entirely lost for that area because there will not be another tower close enough to pick up the slack....

      • If you go to the expense of having a PC thats SERIOUSLY hardened against failure (as opposed to maybe just throwing in a UPS and some disk striping)
        then it'll probably cost you as much as the hardware its attempting to replace. Obviously they following the better-than-nothing approach here with a cheap price but not 5 9s reliability.
      • The article talks about a standard PC, which might mean a hardened box, but I doubt it. A unit such as you describe is no longer cheap, and makes dedicated hardware cost competitive again.

        As for reduncancy, when I worked in the telecommunications industry - not wireless, but optical long-haul - even having redundant machines in the same physical location was regarded as unsafe.

        What if there is big power failure? A serious fire? A flood? A plane crash on top of the station? A meteor strike? There's resilie
      • "Researchers have successfully tested a system that can replace a cellular tower's room full of communications hardware with a single desk-top style computer, making the technology affordable for small, rural communities."

        From http://www.nsf.gov/od/lpa/news/03/pr03117.htm which is the OFFICIAL PRESS RELEASE.

        A single desktop. Sounds incredibly stupid to me. I mean, you gotta cough up the cash for the antenna and transmission equipment, why cheap out on the hardware? Sometimes saving money doesn't make s
    • OK, lets consider that this computer has a hard drive failure. Lets also assume that this computer is a Gateway 7450R rackmount server. Now consider that this is a relatively cheap server with scsi 160 in raid 5. No problem that your hd just crapped out. Run that with two ov these servers and cluster them, you have total redundancy. You could even shoot the other node in the head and it would still keep on trucking. 8 grand and a bookshelf in your closet is more than enough to replace a room full of e
    • Well a simple i386 Linux PC that operates with a HD doesn't exactly meet the five 9's of reliability that you need to operate telcom services, but that is what Carrier Grade Linux is for. OSDL is working on, and has released specifications for CGL, a spec that quote "provides standards based, open architecture software platform for converging telecommunications/data communications systems, which require virtually zero downtime." Linux is currently making some major inroads into the telcom sector, replacing
    • Doesn't matter, another cell will take over.

    • But is the PC as reliable as a room full of communications hardware?

      They aren't going to call up Dell and say they need a system. They're going to get a system from a manufacturer that deals in enterprise-level, high-reliability, fault-tolerant computer systems.

      From the article, it seems this is mainly intended for areas where it isn't isn't economically feasable to put up an expensive, conventional cell-phone tower.

  • This could be a serious cost saving (Score:4, Interesting)

    by Anonymous Coward on Wednesday October 08, 2003 @04:05AM (#7161189)
    Not only will this allow cellular rollouts in poorer countries, expect to start seeing this in small pico cell sites across the world. I work for a company that produces network management software, and I know how complex a rollout process for single cell site is. The lists of equipment are huge and costly, and we have an entire set of modules that allow companies to keep track of the hardware in each site and its configuration. In short, cells sites are complex, costly to build and hard to maintain.

    Replacing all of that with a tower, antenna and a PC would be a huge saving, both in terms of planing, installation and maintainence. A single site could be rolled out in a matter of weeks, rather than months, and cost a fraction of what it costs now.

    For us in Europe, maybe it could help reduce costs and get the debt-laden operators back on their feet. For those of you in the US, you could well see much better coverage on all networks.
  • Linux just keeps demonstrating how it's more equal than anything else. Whatever your systemL complex, large, small, embedded, superclustered, it's starting to be obvious that Linux is the best way of making it come alive.

    2003 will be remembered as the year that the word "Linux" became synonymous with cheap, reliable, omnipresent operations.
    • Linux just keeps demonstrating how it's more equal than anything else.

      This story shows nothing of the sort. Its not about how linux is the 'end all, be all' operating system for every kind of hardware. Its more about how a cheap, general purpose piece of hardware (the ubiquity of which having virtually nothing to do with linux) can serve the function of a larger set of very expensive, specialized hardware.

      If the group had instead ported linux to that 'closet full of communications equipment'm your poin

      • This story shows nothing of the sort.

        If you take a step back and look at the big picture, it shows exactly that.

        If you build something really new (or replace something from the ground up as in this example) Linux is the way to go. There are no "switching costs" holding it back, there are no desktop apps or games needed. Open Source is the only sane choice.

        I believe in Linux as much as anyone, but I don't doubt they could have done the same thing with a windows box, or an OS X box.

        Wrong. The goal was

        • Wrong. The goal was to build a cheap solution that is not dependent on a single provider (because that provider will screw you).

          I got the impression that the goal was to find a way to replace specialized equipment that costs hundreds of thousands, if not millions of dollars, with equipment that was much cheaper.

          The whole 'the provider will screw you' argument is dubious. Windows and Mac OS X boxen are commodities, so its not as if Apple or MS will be able to apply pressure to some community using store

          • The whole 'the provider will screw you' argument is dubious. Windows and Mac OS X boxen are commodities, so its not as if Apple or MS will be able to apply pressure to some community using store bought machines to give them more money.

            What if your not-connected-to-the-Internet machine doesn't work because of WPA? What if it turns out that some servicepack "alters the deal" and you now need thousands of CALs?

            I'm sorry that I don't have a link, but something similar happened to an airline: They wanted to

            • OSS (not necessarily Linux) is indeed the best solution in all cases in which 1) you need an OS and 2) need only an OS and no special apps/drivers/niche-features/etc (because you create all your apps yourself).

              A few more places where CSS might beat OSS.

              • the minimum hardware needed to run your app doesn't run an OSS OS, like if all you need is a 6502 at 4Mhz it makes little sense to buy a 386SX so you can run Linux (of corse int he low end case you frequently write the OS on your own, you need to make
              • the minimum hardware needed to run your app doesn't run an OSS OS, like if all you need is a 6502 at 4Mhz it makes little sense to buy a 386SX so you can run Linux (of corse int he low end case you frequently write the OS on your own, you need to make sure you will ship enough units to that the $10 cheaper hardware will cover the extra NRE of working in such constrained hardware and maybe writing the OS as well)

                With that hardware you have no OS in a classical sense at all, you implement your apps right on

          • I got the impression that the goal was to find a way to replace specialized equipment that costs hundreds of thousands, if not millions of dollars, with equipment that was much cheaper.

            I think you are right...however that gives a free OS like Linux a few advantages. One there is no purchase cost for the OS, so your per unit costs go down (by $200 if you have to buy WinXP retail, or maybe by as little as $5 if you buy a huge number of WinCE licencess). Two you can run on a wider array of hardware then

  • GNU Radio (Score:4, Interesting)

    by metatruk ( 315048 ) on Wednesday October 08, 2003 @04:13AM (#7161217)
    Sounds sorta similar to GNU Radio [gnu.org].
    It's cool that as computers get faster, you can have software replace hardware :-)
    • This doesn't appear to be the same thing as a software defined radio, where almost all of the analog circuitry (LOs, mixers, IFs, demodulators) is replaced with a DSP and software. You need some very fast DSPs and ADCs to do that. You might be able to use a PC to process a demodulated GSM channel.
      • True. However, I meant that it was similar in concept, not necessarily the same thing in function.
    • It's cool that as computers get faster, you can have software replace hardware

      Tell that to the linux laptop folks who have WinModems. :)
      • That's one of the first things I thought of and then realized that there are two important differences.

        1) It was designed from the ground up to run on Linux. Possibly the biggest problem that 'linmodem' driver developers had was getting specs from manufacturers. Obviously that's not an issue here.

        2) When winmodems first appeared in the early Pentium days, resources were scarce. Running one on a desktop system that had lots of other things needing those same resorces was a problem. Now even most low end PC
    • You've still got a major piece of hardware grabbing the signal and getting it into your computer.

      About the only advantage software defined radio has, is that it's one common piece of general-purpose hardware to do everything. You could do the same thing by having inexpensive modules hook-up to a similar hardware device. Having software doing the job only ensures that it will never be effecient or feasable.

      Just think... How much would you have to pay for a very fast computer that would be able to do MPEG

  • Secure? (Score:4, Interesting)

    by benpeter ( 699832 ) on Wednesday October 08, 2003 @04:15AM (#7161223)
    Hardware is generally far more difficult to compromise than software, esp' a known operating system (regardless of how much more secure it may be than other cough, doze, boxes) You'd want some very secure remote access if at all. Otherwise you could find yourself with a whole bunch of phones ringing a la lawn-mower man style in a country town near you.
    • Nowadays the only difference between hardware and software is:

      It's software if you configure/program it. It's hardware if someone else does it.

      Is a dial up modem hardware or software? Is an Intel P4 processor hardware or software?

      The fewer things you can do to something, the harder it is to compromise it. But just because you don't know nearly the full range of things possible on a piece of "hardware" doesn't mean others don't, esp those who know it as "software".

  • Comment removed (Score:5, Informative)

    by account_deleted ( 4530225 ) * on Wednesday October 08, 2003 @04:21AM (#7161250)
    Comment removed based on user account deletion

  • ancient stuff? (Score:5, Informative)

    by Anonymous Coward on Wednesday October 08, 2003 @04:22AM (#7161253)
    I'm a student of telecommunications at an university of technology in Finland, and we've had compact basestations gathering dust at a student lab facility for _years_. (one Nokia and one Siemens, if I remember right)

    The unit was about two mid-tower cases of volume, had an integrated PC, integrated antennaes, the whole bunch. Everything you need for a GSM basestation. And it really is an old model. Modern models are at least more efficient (with directional tracking antennaes, etc) and more inconspicious (they can look like fake chimneys, parts of wall, etc, so that it doesn't disturb the landscape.)

    Probably we're not even talking about the same things since calling a basestation unit a "tower" is ridiculous. Maybe they've replaced the switching centre with a PC? Though I doubt it, since a PC/Pentium would be severely bandlimited to handle thousands of connections. Perhaps with dedicated hardware which is merely controlled by a PC..

    • Re:ancient stuff? (Score:2, Informative)

      by Anonymous Coward
      It looks like they've integrated the line card, switch, backend control functions and possible also the TRX's into one PC, and replaced the general functionality of some of the TRX's with software.
    • Are you talking about the Nokia InSite [nokia.com] BTS?

      I don't see what it so revolutionary about what Venu is doing, there have been small, cheap BTSs around for many years.

      • tsk tsk, you shouldn't take away excuses of american cell providers for not providing adequate service. besides, would you except people from texas to settle on something that small?-)

        united states has roughly double the population density of finland(~30 vs ~16 per square km) for example, and practically all of lapland has cell coverage, while the population density in lapland is 2.2 and most of of the areas are under 10 per square km. so the 'rural' excuse is worthless. the telecom companies however seem

        • Re:ancient stuff? (Score:3, Insightful)

          by RevMike ( 632002 )
          the telecom companies however seem to have missed the point of building a good service(build a good cellular service and the users will start using it).

          There is another part of the equation, however. I don't specifically know about Finland, but in many parts of Europe the wired telephone carriers were absolutely horrible. For instance, a few years ago I know some people who were interconnecting some offices in Athens. They needed to build a radio link because there was a 9 month lead time to get a cir

        • Re:ancient stuff? (Score:2, Insightful)

          by dedalus2000 ( 704571 )
          Is it posable that finland's population is more evenly distributed or that the density of rural finland alone is greater than say parts of oregon or west texas?
          • not really, as the ac said you can end up travelling 100km for post office(or the state monopoly for alcohol) if you live in the wrong place in lapland.

            most people live in southern finland, northern & easter finland are quite rural.

            and from the look of the postings(by americans complaining cell coverage) it looks that the people who are complaining do live in population centres of some sort anyways(not so central suburbs and others with plenty of customers around), if there's population worth mentioni
    • I remember reading year(s) ago about a card which was supposed to go into a low cost PC which could switch up to 4000 calls. Don't hold me to that number, but it was some very large number. Perhaps this is it finally being deployed.
  • Voice calls are good, but wouldn't it be even better to also support Internet connectivity on the network.

    Take a look at openggsn [openggsn.org] which is developing an open source GPRS core network. Maybe the Vanu people could use this to also allow Internet communications for their SW basestation.
  • I think I need to forward this to AT&T. They seem to be unable to build a tower within range of my house. It'd be really cool to get reception in my neighborhood without building a parabolic antenna to mount on my phone.

    Hopefully this means good things for companies that own and operate cell towers in the US. One thing most cities here lack is decent coverage with the services you're paying for. I live in southern California which is pretty densely developed. Coverage in the inland areas can be pretty
    • "They seem to be unable to build a tower within range of my house. "

      Try a land line. You know , those old fashioned phones that plug into a wall and don't require
      good RF reception? Jeez , what IS this obsession with cellphones people have , they're just telephones for chrissake! If your cell had a wire coming
      out the back and had to be plugged into a wall socket would it be quite so "kool" then?
      • A landline would be fine if I could carry it around with me and had a decent long distance plan. MCI's Neighborhood deal costs as much as a good cell plan and isn't mobile. AT&T's Unlimited plan only works if both parties are AT&T customers which sucks. All the resale carriers want to add $30+ to an existing landline bill which after taxes ends up running about $20 itself. For the price of any of those you can have a decent cell phone plan with a subsidized - free or cheap - cell phone.

        If you're aw
  • Unlike the other insightful posters, I'm just a regular slashdot drone^H^H^Hreader making a lame joke when I say:

    Oh-oh! Cheaper than a roomful of equipment? Just wait until SCO hears they are using Linux. Then it'll be cheaper to have a roomful of equipment again.

  • GSM vs. CDMA: do we need those towers? (Score:3, Interesting)

    by ControlFreal ( 661231 ) <niek@berg[ ]r.net ['boe' in gap]> on Wednesday October 08, 2003 @05:35AM (#7161402) Journal

    At first, it seems that the solution portrayed in the article would make the deployment of GSM networks easier and cheaper. This would not only be a solution for developing countries, but also for rural areas in western countries. An illustration of this last point is readily made by comparing the GSM coverage of a densely populated country like The Netherlands [gsmworld.com] (former state provider KPN) to that of a much more sparsely populated country like the US [gsmworld.com] (AT&T wireless).

    However, GSM is not the only cell-phone standard there is. Another standard which is often used in rural areas is CDMA [cdg.org]. It seems this standard features larger cells, and fewer base stations (for, of course, a less densely populated cell). Indeed, Verizon has plans to convert parts of its network to CDMA: see here [newsfactor.com].

    Does anybody have altual experience with deploying CDMA networks? (obviously, given the coverage map for GSM, I don't need that experience in Holland ;)

    • Plans? Verizon has had a CDMA network for quite some time now. Sprint's network is, and always has been, 100% CDMA. Both offer 3G data services (1xRTT is 144kbps which technically qualifies it for 3G status).

      Verizon has the best coverage in the US largely because of their use of CDMA. People who complain about coverage in the US usually have GSM providers (T-Mobile, Cingular, ATT). Verizon seems to be rock solid - not 100% coverage but decent none the less.
    • "Does anybody have altual experience with deploying CDMA networks?"

      Not surprisingly, the US has the most CDMA towers (and, ironically, the most GSM towers) of any nation in the world. This is largely because the countries of the EU are not counted as a single nation, but nonetheless, the US has plenty of CDMA towers in service. CDMA isn't particularly new (it's been around for years), it's just that it's getting more attention now that 3GSM is based on wideband CDMA technology (WCDMA).

      We have many, many w
  • The system offers the hope of making cellular technology more affordable for small, rural communities

    Well I hope that's not the only reason. How about just having coverage all over America for starters? And cut out the damn roaming charges.

  • I wonder how much modification they did to the kernel. Perhaps the equipment in the tower only does switching and reading, but no translation? Linux not being a real time OS, I wouldn't expect it to handle communication that well. In fact just as poorly as any desktop computer handles data aquisition.

    This is nice to hear. I'm resting a lot of my investment dollars in Linux!
    • There are real-time variants of the Linux kernel, and at best all they had to do was write a kernel module which would talk to the transmission devices. They may have even used the V4L API to do it. And the presence of a software GSM library here (http://kbs.cs.tu-berlin.de/~jutta/toast.html) would have made writing the software much easier as well.
    • Linux not being a real time OS

      Cell phone calls aren't real time either. If you stand next to someone and talk to them on a cell phone there's almost always a very perceptible delay. But by human perceptive standards, its not noticeable unless you have the contrast of no delay to look at.

  • A/D is the bottleneck (Score:3, Interesting)

    by bulletman ( 254401 ) on Wednesday October 08, 2003 @06:04AM (#7161487)
    The main reason why software defined radio (SDR) hasn't yet taken off is insufficient A/D performance. And it's not the sampling rate that's the issue; A/D's exist now with sampling rates in the gigahertz range.

    The bottleneck is in dynamic range -- there can be a large difference between the weakest and strongest signal in an channel (80 dB is one example). To sample with enough resolution to capture that dynamic range, you need a lot of bits. But the more bits you use, the slower you have to sample; it's a tradeoff.

    Until A/D converters advance quite a bit more, SDR won't fulfill promise.

  • Smart family (Score:3, Informative)

    by Halvard ( 102061 ) on Wednesday October 08, 2003 @06:06AM (#7161495)
    Vanu is the son of Amar Bose, founder of Bose [bose.com], the maker of all of those great speakers. Another MIT [mit.edu] wizkid.

    • Re:Smart family (Score:2, Offtopic)

      by keesh ( 202812 ) *
      Unfortunately, Bose speakers mostly suck, but they have a really good PR department. The phrase "reality distortion field" comes to mind.

      If you're after decent speakers at a similar price, buy KEFs.
    • If you think Bose has ever made a consumer level quality speaker, you haven't heard good speaker!

      But that doesn't change the fact that he's a smart guy. :)

  • You know what this means? (Score:3, Funny)

    by TerryAtWork ( 598364 ) <research@aceretail.com> on Wednesday October 08, 2003 @06:24AM (#7161549)
    It means we can have our own phone networks! Is there ANYTHING we can't have? I know! A GIRLFRIEND!

  • More details in the whitepaper... (Score:5, Informative)

    by darkov ( 261309 ) on Wednesday October 08, 2003 @06:48AM (#7161607)
    The poster should have included this link [vanu.com] (pdf) - much more interesting.
  • Here, in Poland it's very common that smaller ISPs use old 486 and pentiums as routers to provide net for a single block or several houses. This works well and is very cheap... except that the PCs were never meant for 24/7 use and simply they fail after some time. Those that can be easily repaired, are repaired, those FUBAR are dismantled for spare parts to repair the ones mildly broken and it works and still pays to replace them with other second-hand computers. You get what you pay for, the service has be
    • I wonder how much better things would get if they would find a way around using the hard drives. I have had a friend's old 486 running as my router (Linux Router Project) continuously for several years--the HDD isn't even connected to the motherboard. But the thing is, it was only 500mb in the first place--easily replaced these days with an SD card or something.
      • Note if you have enough RAM and APM, you can safely spin down the drive when unused. Although, what dies most often in the PCs mentioned are not harddrives but power supply, network cards and motherboards. (when you draw thin ethernet (BNC/TP) between houses, the network cards fry during most storms, some of them don't stop the charge and all the rest gets fried too.)

  • Info from Vanu, Inc. (Score:3, Informative)

    by Anonymous Coward on Wednesday October 08, 2003 @08:34AM (#7162130)
    I'm CTO at Vanu, Inc. Here's some additional info that some posters to this thread have asked about.

    - Linux version: we're using a Debian 2.4 release with the real time patches. All the signal processing code runs as an standard application level process.

    - A/D and D/A: we're using an external RF front end that provides over 90 dB spurious free dynamic range. The poster who said these are big and hot was right; it's a little smaller than a PC case all by itself, with a hefty fan to dissipate the heat of the power amp. It covers 25 MHz worth of spectrum and costs a lot more than the HP server that does the signal processing.

    - software features: the linux applications running on the HP server handle the complete transmit and receive chains. We go from raw digital samples on one side (exchanged with the A/D and D/A converters) to voice and data packets on the other. A separate HP server runs the Base Station Controller functions, which are the protocol logic, handover control, and similar functions.

    - reliability: a huge advantage of building the GSM software on top of linux is that it's portable. Some operators want the level of reliability that comes with commercial grade servers; some want the level that comes with telco grade servers. The GSM basestation software runs on whatever they need.

    It's great to see how much interest there is in the slashdot community about this.

    -john chapin

  • But can it work on 2.4GHz...? (Score:4, Interesting)

    by no_such_user ( 196771 ) <[jd-slashdot-200 ... dreamallday.com]> on Wednesday October 08, 2003 @09:00AM (#7162373)
    So if we're now able to make carrier-quality telecom equipment that runs on fairly run-of-the-mill PCs, why are we still paying $50/mo to our mobile phone companies? Think of the revolution that's happening with 802.11, and now imagine a Linksys GSM Router sitting at home next to your Wi-Fi box. Of course our governments would never allow this to take place; who would pay billions to claim stake to the airwaves if we could build our own homegrown networks?

    In reality, we'd probably NOT have personal GSM routers as I mentioned above... instead, we'd have community organizations sponsoring local sites, paid for and maintained by their users. Interconnected with other communities, it would form a massive network of telecom co-ops. If linked by microwave, you might not even need to involve your local utilities one bit.

    I'm not suggesting that we dismantle the existing mobile networks; however, they are truly OUR airwaves. If we could see to it that a mobile network running on hardware like this were to be built using non- or minimally-licensed (community licensed?) bandwidth, a couple of years of network instability and growth could build a true grass-roots, free-as-in-speech-AND-beer telecom network.

    Who's with me?
    • One reason we're still paying so much is that this stuff isn't commercially available yet. This was just the first trial. It will be a year or more before the carriers are even able to get this stuff, and then they still have to roll it out.
  • "Can you hear me now? Good! You now owe $799 to SCO!"
  • This is outrageous! I demand that Terrans and the NCs get something equally cool!

    Or at least that I get a chance to try this new stuff out myself.

    (whaddayaknow, the sad thing is that nobody will get this reference) :-)

  • Aha! (Score:2)

    by sharkey ( 16670 )
    Pentium-based computer

    So that's why my phone keeps trying to dial 0.99834664850!

  • The downside of this plan?

    The form factor for the PC case is 600 meters tall.
  • The Vanu Sovreignty [vanusovereignty.com] rocks...always kicks the Terran Replubic's and New Conglomerate's all over the planet and back!... ;)

  • It's been done, although usually with DSPs (Score:3, Informative)

    by Animats ( 122034 ) on Wednesday October 08, 2003 @12:19PM (#7164855) Homepage
    Cell phone base station equipment has used software-defined radios for a while now. [analog.com] The first ones appeared around 1996. Watkins-Johnson discontinued such a product in 1998. [siliconstrategies.com] Without them, multichannel CDMA would be really expensive. With them, it's affordable. It's been years since base stations had one physical radio per call.

    It's neat that Vanu is doing this on Linux, but it's not like it's a revolutionary technology breakthrough.

    There's still an analog RF radio involved; all the digital processing is at the IF frequency. Digital signal processing of raw RF in the gigahertz range is still a bit out of reach. (And it will require an A/D with huge dynamic range.)

    It's not clear that it's a win to do this using commodity PC hardware. Most of the crunching is in tight signal-processing loops that don't use much memory. With custom boards, you can have more CPUs on a board. Squeezing the physical size down matters in this application. If you can put the gear in a box on the pole, instead of needing a little shed, that's a big win. PCs also tend to use more power, and thus generate more heat, than DSPs per MIPS. Cooling all the gear is a constant headache in the cellular business. It typically doubles the power consumption, and the air conditioners themselves are maintenance headaches. What the industry wants is gear that doesn't require air conditioning, at least for smaller sites. Qualicomm [qualcomm.com] has been shipping pole-mounted CDMA base stations since 1997.

    It's also not clear that introducing a network between the radios and the processors helps reliability. If the radios are flexible enough that one can take over the job of another, it's easier to fail out a radio/processor pair and switch in another one.

    None of this matters all that much because the cellular base station equipment industry is in the tank. The industry overexpanded based on forecasts of huge needs for 3G gear, and that didn't happen.

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