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Cellphones Networking Canada Communications

Sending Data In Bursts of SMS Messages 181

An anonymous reader writes "Canadian carrier Rogers has been experiencing some extreme loads of late, as researchers at the University of Waterloo investigate the potential for sending data spread across bursts of hundreds of text messages. They sent around 80,000 messages in the course of a project testing a new protocol able to cram 32KB into 250 messages sent from a BlackBerry, reaching a rate of 20 bytes per second. The group thinks its protocol could be useful in rural areas of the developing world where text messaging is the only affordable, reliable link."
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Sending Data In Bursts of SMS Messages

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  • Oops (Score:5, Funny)

    by ekgringo ( 693136 ) on Thursday June 24, 2010 @04:12PM (#32682828)
    Make sure you get the "unlimited" text messaging plan before trying this...
    • by colinnwn ( 677715 ) on Thursday June 24, 2010 @05:02PM (#32683588)
      I have to pay $10 when I text "HAITI" to 90999! I thought Microsoft was paying.
    • Re: (Score:3, Insightful)

      Yeh, I really don't get it myself.

      Quick calculations, your average 1hr TV show would end up costing you around $500 000 if you didn't have a cap.

      Why even research this technology? It's not like we weren't aware that SMS was capable of this, it is text after all. I see nothing of value in this research, I'm sure that someone with a bit of coding skills and access to a mobile could do this without much hassle.

      I'm usually the first to say to people on slashdot that research is worthwhile, but this is really st

      • Re:Oops (Score:5, Informative)

        by TheRaven64 ( 641858 ) on Thursday June 24, 2010 @06:47PM (#32684938) Journal

        It's completely idiotic. There are two ways in which SMS is implemented:

        On older GSM networks, it's part of the control channel. There is some unused space in one of the control packets. It was a scarce resource and flooding it could actually prevent anyone making calls (there was a fairly simple DoS attack possible). This was the original reason for SMS being expensive - the network couldn't handle much SMS traffic.

        On newer networks (GPRS and newer), it's just treated as data. It's wrapped in a packet header indicating that it's SMS and then sent in the same way as IP data.

        In any area where you just have GSM, there isn't enough bandwidth available for SMS for this to be useful. In an area where you have GPRS or anything newer then SMS is just a way of adding a huge packet header to your IP packets. It's transmitted the same way as IP data, you're just using the available bandwidth less efficiently.

        • Re:Oops (Score:4, Insightful)

          by newcastlejon ( 1483695 ) on Thursday June 24, 2010 @07:04PM (#32685086)

          ...In any area where you just have GSM, there isn't enough bandwidth available for SMS for this to be useful.

          In these circumstances CSD is probably available too at a heady (in comparison) 9.6kbps.

          • by cromar ( 1103585 )
            God is the universe (or more?), or as the Hindus call their Supreme God Head, Brahma: literally "Reality."
            I'm not religious but some can be learnt, for good or ill, from the various faiths of the world.
            Anyway, their is seriously only one entity -- Reality -- over which we and everything else are more or less a distribution of matter and energy (or who knows what more).
            You probably think that's all poppycock, but I wondered...
            • by cromar ( 1103585 )
              Or Brahman [], even. Or the Tao, maybe. "The Way." That part of human Reason that doesn't understand names. Anyway...
        • You are assuming this is to solve a technical issue, that they are trying to efficiently use resources.

          However, if you consider that they are trying to solve an issue with how phone carriers charge for data usage, you will see where this might provide value.

          You are correct about text messages on modern networks being just data; however, providers do not charge the same for this data usage.

          In some places, they charge much more for text messages than data usage (here in the U.S. is an example of one of those

  • by Joe The Dragon ( 967727 ) on Thursday June 24, 2010 @04:14PM (#32682858)

    so now will they bill $1 per txt each way?

    • by geekpowa ( 916089 ) on Thursday June 24, 2010 @04:34PM (#32683140)

      In emerging economies SMS is dirt cheap. In Philippines: $0.50, 24 hour all you can eat (on-net only) deals are common.

      This is a bad idea for a large number of technical reasons : very inefficient use of the GSM channel because of all of the excessive handshaking and control just to transmit a 140 byte data packet for one (sms is 7bit per character. 160 chars = 140bytes) and rubbish throughput & latency. But economically it makes sense. Also accessibility of 2G mobile phones is very high in such environments, 3G wireless or twisted pair copper not so much. Depends where you deploy it, for what eventual purpose and actual real bandwidth requirements.

      • by fuzzyfuzzyfungus ( 1223518 ) on Thursday June 24, 2010 @05:42PM (#32684200) Journal
        It's an especially terrible plan, if widely adopted, because SMS comes out of the control channel. If you have enough SMS traffic flying around, the carrier will either have to start dropping it, or have plenty of available voice/data channel lying idle because they don't have enough control channel capacity to set up and tear down calls.

        Obviously the poor people in the sticks might not have fancy 3G stuff; but why would you attempt to shove data over SMS(aside from short message snippets from embedded devices, and suchlike applications), when GPRS already exists? All sorts of dirt cheap phones support being used as modems, without any special software, and, while it might well be more expensive now, for economically perverse reasons, SMS won't be cheaper for long if it becomes standard practice to do general-purpose data transfer over SMS on a large scale...
  • by Overzeetop ( 214511 ) on Thursday June 24, 2010 @04:15PM (#32682870) Journal

    ...and got to feel the thrill of competition again.

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      Yeah, how backwards is this text method? Put the phone on one of those old modems al la Wargames [] and send data like it's 1989!

      • aka an Acoustic Coupler [].

      • Re: (Score:3, Informative)

        by Nethead ( 1563 )

        You must be young. I remember using acoustical modems back in 1974 and they weren't that new back then. The reason we used them was because it was illegal to connect to the copper on a POTS line back then and Ma Bell's solution was VERY expensive and very non-portable.

        • by bill_mcgonigle ( 4333 ) * on Thursday June 24, 2010 @06:01PM (#32684472) Homepage Journal

          I remember using acoustical modems back in 1974 and they weren't that new back then

          I've actually considered seeing if I could get a v.32 in-software stack to communicate over the bluetooth headset/microphone protocol so I could do very basic data networking over a cell phone without a data plan. Like ssh.

          I came to my senses, but I kinda still want to try it anyway.

          • by tepples ( 727027 ) <> on Thursday June 24, 2010 @06:45PM (#32684924) Homepage Journal
            The lossy compression used in digital cellular telephony has a smearing effect that screws with the rapid phase transitions used by quadrature amplitude modulation. You aren't going to get a lot of bits per second out of digital voice.
            • the rapid phase transitions used by quadrature amplitude modulation

              ah, good point. I wonder who's done research into modulations that can survive better. Maybe some FEC in the data stream (if it could exceed 300bps, say)?

          • by adolf ( 21054 )

            I don't think I've ever had a cell phone (except my most recent, which is a Motorola Droid) which was unable to do that by itself.

            The process is simple: Connect it to a PC with an appropriate cable (and the appropriate drivers, if applicable), start issuing AT commands, and go.

            I used to dial a local ISP like this every now and then, and I've sent faxes with it back when that still mattered.

            Billing was the same as a regular voice call, and data rates were pretty ugly compared to what we're used to these day

        • Re: (Score:3, Informative)

          by pyrrhonist ( 701154 )

          The reason we used them was because it was illegal to connect to the copper on a POTS line back

          That became legal in 1968 with the Carterphone ruling. You probably had an acoustic coupler in 1974, because the modular jack wasn't introduced until 1976.

          • by Nethead ( 1563 )

            We did have the 4 prong plug. IIRC the DataSet 300 used an RJ21 25 pair connector and came with a modified 5 line keyset.

      • Re: (Score:3, Insightful)

        by xaxa ( 988988 )

        ...or just buy the data cable (or USB cable, if your phone uses USB) and download the modem drivers.

      • >>>send data like it's 1989!

        A wee bit off laddy. 20 bytes/second == about 200 bits per second, which is ancient technology. More like 1979 - break out the disco and the polyester pants!

        I'd sooner use a 56k dialup modem, even if the noise on the lines only let me do 24,000 bits per second (as has happened in some low-budget motels). Or a wireless modem. It's a lot faster than the text 0.2k SMS messaging method.

        • ok
          you bring your modems and I'll use this.
          we'll go to Africa, somewhere random, like Congo or Darfur. We'll both use our preferred method to call for help. Survivor is the winner.

      • by drewhk ( 1744562 )

        Well, GSM codecs will wreak havoc on these modems, as GSM voice channels are not simply bandlimited like POTS, but they use an artificial acoustic model of human voice tract.

  • by clone53421 ( 1310749 ) on Thursday June 24, 2010 @04:17PM (#32682902) Journal

    You pay: Monthly for a cellular package with unlimited texting
    You get: 20 baud

    • by schon ( 31600 ) on Thursday June 24, 2010 @04:22PM (#32682984)

      You pay: Monthly for a cellular package with unlimited texting
      You get: 20 baud

      Actually, (ignoring the fact that "baud" is the incorrect term) that would be either 160 or 200 baud, depending on whether you include error correction bits in the calculation. :)

      • Whoops, yeah, slipped my mind when posting. 1 byte per second = 8 baud (bits per second).

        • by cuby ( 832037 )
          1 byte per second = 1 baud (SYMBOL per second) if a symbol is represented with 8 bits.
          In the case of the SMS (short message service) one symbol has 7 bits, so, for 1 message per second you get: 160 baud; 160*7=1120bps; 1120/8=140Bps.
    • You pay: Monthly for a cellular package with unlimited texting You get: 20 baud

      What's so new about this? Seems that's what AT&T gives most iPhone users anyway...

  • by Itninja ( 937614 ) on Thursday June 24, 2010 @04:17PM (#32682904) Homepage
    In a completely unrelated story, the University of Waterloo has an unexpected ~$16,000 shortfall this quarter.
  • by nweaver ( 113078 ) on Thursday June 24, 2010 @04:17PM (#32682914) Homepage

    Text messages are one of the most awful forms of data on the cell network. On a 3G type network, they are just data, so hey, if you can do TXT on 3G, just do data. So what?

    But on older networks, such as the proposed usage, they take up CONTROL channel space, and too much SMS is a DOS attack!

    See Exploiting Open Functionality in SMS-Capable Cellular Networks []:

    ABSTRACT: Cellular networks are a critical component of the economic and social infrastructures in which we live. In addition to voice services, these networks deliver alphanumeric text messages to the vast majority of wireless subscribers. To encourage the expansion of this new service, telecommunications companies offer connections between their networks and the Internet. The ramifications of such connections, however, have not been fully recognized. In this paper, we evaluate the security impact of the SMS interface on the availability of the cellular phone network. Specifically, we demonstrate the ability to deny voice service to cities the size of Washington D.C. and Manhattan with little more than a cable modem. Moreover, attacks targeting the entire United States are feasible with resources available to medium-sized zombie networks. This analysis begins with an exploration of the structure of cellular networks. We then characterize network behavior and explore a number of reconnaissance techniques aimed at effectively targeting attacks on these systems. We conclude by discussing countermeasures that mitigate or eliminate the threats introduced by these attacks.

    • The intended use of this is for once a day updates of information to locations with poor internet connectivity. These people weren't pulling in high data to begin with, and likely were sending even less. For example, if all you need to do is send crop prices, weather reports, etc that update once a day, then you can just push all that data once a day over SMS.

      Beyond that, as a student currently at Waterloo, I'm fairly certain that this PhD student, some prof, or some other smart ass student (there are a LOT
  • Huh? (Score:3, Insightful)

    by Monkeedude1212 ( 1560403 ) on Thursday June 24, 2010 @04:18PM (#32682934) Journal

    They couldn't have built their own network and emulated phones to test this protocol, they had to go live with their phone provider? Some University. I bet MIT is laughing out loud.

    Also, how's the coverage out there? []

  • by Applekid ( 993327 ) on Thursday June 24, 2010 @04:20PM (#32682958)

    Anyone care to describe why they couldn't just use airtime minutes and an acoustically coupled modem? Looking it up on Wiki, in general they were able to transfer 300 bps instead of 160.

    • Re: (Score:3, Insightful)

      by Pentium100 ( 1240090 )

      Or just use a phone that has a modem, most of new ones do, IIRC you can get a few kilobits with it.

      • This is for rural places, maybe they didn't want to depend on recent phones. A ten year old phone can be connected using a serial cable and you can send SMS using AT commands.

        • Re: (Score:3, Insightful)

          by petermgreen ( 876956 )

          I thought most phones that could talk to a PC could at least do an old fassioned GSM data call (which is very slow by modern standards but still fast comared to this).

          A friend of mine has an old HP dos based PDA which has a socket in the back for a nokia 2110 and we managed to get it to dial up an ISP and access email.

          • The Nokia 3310 (most common phone here in Portugal shortly after it was released) didn't have a modem interface - I know because I've tried.

            Many old phones didn't, it depended on the price, afaik.

    • Re: (Score:3, Insightful)

      by sznupi ( 719324 )

      What they're doing is just an awkward, slow and very limited way of what WAP was doing over a decade ago, also via channels used for SMS.

    • I don't know the specifics but I'd start by looking at whether the digitisation, filtering and encoding/compression of the acoustic signal by the mobile phone system preserves the frequency, amplitude and phase information used by an acoustic modem. (I think 300 baud modems made use of frequency shifting only.)

      Then you could try to design a physical coupler that will interface with the utterly non-standard collection of shapes and sizes present in mobile phone handsets and still exclude sufficient external

      • by erc ( 38443 )

        Totally a waste of time. UUCP over Bluetooth works just fine. Supports arbitrary packet sizes, checkpoint/restart, low overhead, etc. In short, UUCP is designed for efficient data transfer over a low speed unreliable network like the cell phone network, unlike SMS.

        SMS over a cell phone is probably one of the worst ideas anyone has ever come up with. Are we sure this wasn't a late April Fool's joke?

      • I can't imagine that the frequency and amplitude would be reproduced correctly. I think using the phone as an acoustic modem would only work if carriers still supported their analog networks (are there even any left in the world?). The digitization would probably work fine, but wouldn't the loss of any bit seriously hamper the decoding when you try to receive data? Then again, I guess thats what error correcting is for.
        • While the frequency or amplitude will not be reproduced perfectly, you can assume that it won't change by much, for example if you sent 1kHz it probably won't arrive as 2kHz and 2kHz won't become 1kHz. Also, if you send it vs sending nothing it probably won't change that much either, so it's just a matter of figuring out how fast can you go until the signal becomes too distorted to use. Analog modems seem to be pretty capable of determining the speed at which a reliable connection can be made (and the line

  • Let's see, at 20 cents a message that test only cost them $16,000 worth of messages! And they managed to move all of 10MB... If my math is right. They should just spring for the pay-as-you-go data plan at the bargain basement cost of $1.99 a MB, they would cut the "cost" down to 20 bucks!

    Are rural, developing countries really selling unlimited txting plans for affordable rates? If so, why is it that we let carriers in the developed world get away with robbing us blind?

    • If so, why is it that we let carriers in the developed world get away with robbing us blind?

      Because the FCC is run by a combination of ineffective pussies and telecom industry insiders. The people in charge support the cartel pricing!

  • Wrong solution (Score:4, Insightful)

    by maxrate ( 886773 ) on Thursday June 24, 2010 @04:24PM (#32683010)
    Not trying to troll, but this is the wrong 'solution' for so many reasons. If SMS's can make the connection, so can other forms of packet radio.
    • Re: (Score:3, Insightful)

      by colinnwn ( 677715 )
      It's sub-optimal, but not necessarily the "wrong solution". Rather than setting up your own packet radio network, this allows you to piggyback on existing infrastructure for the cost of a mini-USB cable and unlimited txt plan. There may be some valid uses.
    • I think it's the wrong solution but for another reason: they take the network for granted. In the country where I live there are places where you can travel 300 km and find 2 towns. Anyone living between those towns (native reservations, lonely settlers, etc) don't have an antenna anywhere nearby. I don't want to imagine the state of the cellphone network in the middle of Africa, but I suppose that a place with telephone connection is bound to have some kind of internet access.
  • Not even a real challenge.

    Take the available character set; use that as your base (like base64/base92 to send binary data as clear text); toss in forward error correction and a you could do TCP/IP over SMS if you wanted to.

  • by srmalloy ( 263556 ) on Thursday June 24, 2010 @04:31PM (#32683098) Homepage

    ... next year's April 1 RFC -- "IP over SMS Carrier".

  • Why not use yEnc (no pun intended)? It's been working for years on usenet.
  • Speaking on behalf of the interests of the RIAA & MPAA, it is clear to us that this "new" protocol will be used only for the piracy of copyrighted materials. Sure, downloading a DVD using this protocol might seem like harmless way to pass the summer months, but the damage to our industry is incalculable. And although we are headed for another record year, we calculate that this has clearly cost us over $10 billion dollars in losses and must be stopped.

    Jack Valenti
    (Yes, I know I'm dead. Want to

  • Neato! (Score:5, Funny)

    by zmollusc ( 763634 ) on Thursday June 24, 2010 @04:38PM (#32683210)

    This is good news (everyone), by the time you have torrented your bluray rip, it will be out of copyright.
    Or not.

  • by straponego ( 521991 ) on Thursday June 24, 2010 @04:40PM (#32683236)
    I'll mostly leave it to others to enumerate the many flaws in this, except to note that under AT&T I often had text messages arrive hours or days late, or never. But I do have to applaud this group. This is, by a wide margin, the worst idea I have ever seen in a /. story. Are we sure this wasn't a belated April Fool's gag?
    • Re: (Score:3, Insightful)

      Never is, of course, a serious issue; but hours or days late would be solvable with the right protocol.

      Bittorrent, in effect, deals with rather similar issues(since it is typically used to transfer files so large that they make common home internet connections feel like ghastly retro shit) reasonably effectively. It may take a while; but sufficient patience will get you past any number of corrupted blocks, dropped packets, hosts that disconnect, etc.

      Any sort of latency-sensitive application will be ri
    • by Kaenneth ( 82978 )

      Actually, it was an April Fools story.

      They just used the described means to submit it, and it just now finished.

    • Sometimes it's not about being a good idea. Sometimes it's just about seeing if it's possible. Lots of things are like this... like using a fishing pole for flying your kite, or building a makeshift jet engine out of a turbocharger. It's not necessarily practical, but it can be a bit of fun?

  • What about GPRS? (Score:3, Insightful)

    by AC-x ( 735297 ) on Thursday June 24, 2010 @04:47PM (#32683342)

    > The group think their protocol could be useful in rural areas of the developing world where text messaging is the only affordable, reliable link

    It's a fun little project, but in what circumstance would this *ever* be the best use of a mobile network? If you've got the signal for SMS then you should be able to also at least use a voice call to transmit data (not sure what the max would be, 14.4kbps? 9.6kbps?) if not full GPRS (56-114 kbps). 160bps is not very impressive

  • If I'm doing my math right:
    160 character limited frame
    Just using "a-zA-Z0-9" gives us 62 characters - throw in a few punctuation for 64 which we can use for base64/MIME encoding. Giving us 6 bits to use per character(byte)
    Assuming an 8-bit byte in original data, 33% larger
    160*6/8 = 120 bytes, 8 bits each in each SMS
    250 messages of 120 uncompressed bytes each is 30 KB or 240 Kb

    If I remember SMS already has sequencing in its protocol so you shouldn't have to sacrifice your own bits for that. SMS has
  • by Ukab the Great ( 87152 ) on Thursday June 24, 2010 @04:50PM (#32683390)

    Maximum carrying load of a Yak: 70kg
    Weight of a 32GB micro sd card. 0.5g
    Having your own 3rd world petabit network: priceless.

    • Re: (Score:2, Funny)

      by BuckaBooBob ( 635108 )

      This like WiFi degrades significantly with distance..

      Doing some rough math.. A Yak that can go 5km/hour when fully loaded using your numbers can Transter about 25 Peta-bytes per second over 1 Meter... at 25 Meters your down to 1 Peta-byte/s.. This is Payload Only.. It does not include packing or transferring information on and off the SD's. The Latency would be extremely high... I am gussing that the Protocols that have been developed for data transmissions to the Moon might still not have enough forgivenes

  • A single low-end jury-rigged SMSC is well capable of over 5K TPS. 80K messages won't even break sweat on any telco's network.

    That said, it's a pretty useless medium of communicating any significant amount of data. GPRS or even WAP are much more efficient and capable of dialup speeds. And hey, developing worlds have much better telecom networks than these kind of "for developing worlds" stories give credit for. At least in India, SMS is essentially free (costing less than $0.0001 (yes not a typo!) per SMS in

    • That said, it's a pretty useless medium of communicating any significant amount of data. GPRS or even WAP are much more efficient
      Hell even old fassioned GSM dialup is way faster and more efficiant.

  • I'm not one to stand in the way of research - but 20 bytes per second? I'm sure they should be able to design some sort of adapter for 300bps modems and use those over the cell phones as voice signals instead, and have a substantial gain in transmission speed...

    Now considering that most cell phone carriers world-wide actually charge a fee nowadays for SMS messages, ESPECIALLY in underdeveloped countries, sending a whole lot of SMS messages is probably not going to be more economically viable than hiring Jos

  • About 25 years ago, TCP/IP experimenters on BITNET were sending IP packets as RSCS messages, which were limited to the same scale of data as SMS messages. It was slow as hell, but just like the SMS network, the RSCS network prioritized these short messages above other traffic.

    This is the same network facility that inspired the IBM Reseach folks who moved to AOL to create the buddy list and everything that arose from there.

    Funny how things come around over and over in the computing world - it's like nobody

  • if someone were to actually do this, how many minutes would it take for their IMEI and SIM to be permabanned from the afflicted carrier
  • OK, I just don't get something.

    GPRS would be a logical choice for data transmission on a barebones GSM network. Assuming that those "rural" providers absolutely don't offer affordable GPRS, you can use circuit-switched connections and just send our own data instead of GSM-compressed voice. IIRC, most random bit patterns are valid GSM packets (in all variants of compression), so that shouldn't be a problem. I presume one could even encode the data such that it could survive decoding, as long as you have a di

  • Affordable? (Score:3, Insightful)

    by damn_registrars ( 1103043 ) <> on Thursday June 24, 2010 @05:26PM (#32683946) Homepage Journal
    Really? Do these people not have a postal service? Per unit data a stamp is many orders of magnitude less expensive for sending data than a text message.
  • If I remember correctly, there are absolutely no guarantees an SMS will ever arrive (maybe something like within 6 months, but that is practically the same). Seriously. It's traffic secondary to the voice/data traffic. If there is too much SMS traffic, it will saturate the control channel, and the carrier will simply discard it. In developing countries this could potentially bring down cellular networks entirely, if the hardware can't cope with the sudden increase in traffic, rendering people not just d
  • It is totally insane, but given the expense of having a data plan and the usefulness of even tiny amounts of data it actually makes some amount of sense to contemplate routing data over the SMS channel. It's no use for anything real time, but if you are doing things like constantly reporting data (latitude, etc.), sending or downloading things in the background (eg: email) then it might be possible to have no data connection at all and still get significant use out of certain types of connectivity.

    Also, wh

  • I tried to send a small mp3 but my thumbs got too tired.
  • by williamyf ( 227051 ) on Thursday June 24, 2010 @09:27PM (#32686246)

    Remember WAP?

    The WAP service had three posible bearers, GPRS (the best for it), a circuit switched dedicated 9600bps link (later upgraded to 14.4kbps, or even 56kbps), or SMS.

    Well yes, in WAP times there was a full spec on how to transport data on lowly SMS. As other posters have said, using SMS as a bearer for other data services is painfull, slow, ackward, and not such a good idea.

    Ah, this brings memories!

  • Hey that's great. If the dumb kids at Waterloo are excited about 20 bytes / sec, I have this here bleeding-edge V32 modem that'll do over one thousand bytes per second over a plain old telephone line. You can't imagine all the fun I had downloading JPGs on this thing back in the 80's^H^H^H^Hfuture telecommunications lab. Mmmm.. V32, that's like four mustang engines on a modem.

MESSAGE ACKNOWLEDGED -- The Pershing II missiles have been launched.