Please create an account to participate in the Slashdot moderation system

 


Forgot your password?
Close
typodupeerror
×
Wireless Networking IT Hardware

Germans Reach 360 Mbps in Mobile Network Tests 134

Posted by samzenpus from the but-I-want-it-now dept.
povvell writes "German telecomms giant Siemens has managed to hit speeds of an astonishing 360 Mbps in field tests in the centre of Munich using 'orthogonal frequency division multiplexing (OFDM) and the so-called multi-hop technology'. This is not the only demonstration of OFDM producing super fast wireless speeds, as other companies are also working on variants of the technology. It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"
This discussion has been archived. No new comments can be posted.

Germans Reach 360 Mbps in Mobile Network Tests More

Germans Reach 360 Mbps in Mobile Network Tests

Comments Filter:

  • This will help them (Score:5, Funny)

    by Anonymous Coward on Wednesday September 29, 2004 @10:28PM (#10390571)
    Distribute full length David Hasselhoff movies in mere seconds! Fear!

  • How much "radio pollution" would that produce? (Score:5, Interesting)

    by Cprossu ( 736997 ) <cprossu2@@@gmail...com> on Wednesday September 29, 2004 @10:29PM (#10390574)
    360mbps seems like alot for wireless, considering the mess 108mbps (by using 2 different spectrums) created, what would a multiple dynamic frequency wireless setup leave us...what happens when you have 50+ different networks together?
    • Two authorities:
      1) Heinlein's "Waldo"
      2) What happens when many different frequencies exist in the same medium at the same time? You get localized extreme energy spikes. It took, oh, 200 years for this to be understood as actually happening on the ocean, although the math was clear that it would be expected.

      For ubiquitous wireless signals? Oh, probably no worse than upping the background level of energetic cosmic rays by a few orders of magnitude, and it wouldn't be provable harm so no economic cost invo

    • radio pollution and the shannon limit (Score:5, Informative)

      by j1m+5n0w ( 749199 ) on Thursday September 30, 2004 @01:32AM (#10391541) Homepage Journal

      Well, Claude Shannon showed [wikipedia.org] that, with a perfect modulation and error correction scheme, you could only push so much data over a given communications media, with a given amount of bandwidth and SNR. If you want more, you have to either

      • use more spectrum (aka bandwidth)
      • increase signal strength
      • decrease noise

      Since background noise is not controllable, they would have to be doing one of the first two (effectively increasing radio pollution), or overcoming inefficiencies in a previous modulation scheme.

      Anyone know how close the various 802.11 standards are to the shannon limit?

      -jim

      • Re:radio pollution and the shannon limit (Score:5, Insightful)

        by div_2n ( 525075 ) on Thursday September 30, 2004 @02:27AM (#10391739)
        Increasing signal cannot and would not provide you with more bandwidth. It might help you overcome noise thus maximizing your current maximum capacity. But increasing signal also increases the possiblity of reflections which in turn increases noise.

        The best possibility is to use the maximum signal strength required to be "heard" over the noise which, given the possibility of reflections, it is sometimes actually less and not more.

        All things being equal, the only real way to increase bandwidth is to increase the amount of spectrum you use. But not all modulation is created equal as is shown in 802.11g (ODFM) vs. 802.11b (DSSS). Same spectrum, different results. Wimax is one attempt to not only increase the amount of spectrum used, but increase the effeciency of the modulation technique to make the most of the bandwidth in that spectrum.

        That and it also happens to be a theoretical competitor to telcos (cellular included) because of the possibilities it might offer.

        • Re:radio pollution and the shannon limit (Score:1, Informative)

          by Anonymous Coward
          Increasing signal cannot and would not provide you with more bandwidth. It might help you overcome noise thus maximizing your current maximum capacity. But increasing signal also increases the possiblity of reflections which in turn increases noise.

          Wrong. The most effective modulation you can use depends on the SNR. With a given noise level, increasing the signal power allows using a more efficient modulation scheme (packing more bits per baud). The more bits per baud, the highest the SNR required.
          This
        • This is not correct. Increasing the power increases the SNR, and increases the maximimum possible bandwidth.

          Exhibit 1: Shannons law Exhibit 2: Various coding schemes actually make use of the reflections, which therefore is not a problem anymore. One extreme version of this is MIMO systems.
        • OMG. +5 Insightful. I have to do something about it.

          Increasing signal cannot and would not provide you with more bandwidth. It might help you overcome noise thus maximizing your current maximum capacity. But increasing signal also increases the possiblity of reflections which in turn increases noise.

          No. And yes for the last part. But this is not the whole truth.

          Did you know that Maxwell's equations were *linear*? I.e. if you increase the output power by a certain factor, you increase the received power

      • Re:radio pollution and the shannon limit (Score:1, Informative)

        by Anonymous Coward
        Well, the shannon limit only aplies to single input single output (SISO) channels. Future high data rate wireless systems will use multiple input multiple output (MIMO) which exploits multipath channels. Using multiple transmit and receive antennas you can increase data rates without using any more spectrum. I think you can effectively get *N speed up where N is the number of transmit or receive antennas. It works because the channels created by separating the antennas in space by a certain multiple of

        • thanks for the extra info-it is very much appreciated...

          it would also be interesting to get this into the sub atomic field and seeing how certain close bandwidths of photons (as radio waves arn't really waves for se) actually will interact with eachother.

          one wonders how it would screw with theese types of multiple transmissions to have very precise surfaces in which one spectrum of photon would go through, yet one with a spectrum just above it would----
          ok im going off into theoretical (and probably absolu
      • You've missed out an option:
        • Increase spatial diversity

        This is the spatial equivalent to the time/frequency option of 'use more spectrum'. Achieving spatial diversity is typically done by adding more antennas (and RF gear) to the receiver and transmitter.

        As an example, a special (simple) case of spatial diversity is using an array of antennas to do beamforming. Making the antenna occupy more space increases the antenna gain (directivity) allowing multiple data streams to reuse the same frequency.

        • There is no "real" or "fake" Shannon limit.
          The Shannon limit is the same regardless if you use multiplexed data at the source, or a complex propagation model.
          In short, no form of source or channel coding (such as MIMO) alters the limit of the capacity of the channel.

          As far as MIMO matrices go, the elements of the matrix represent the configuration of Tx antennas (coefficients representing the source signal) in relation to the the number of channels (coefficients that represent the radio channel envelope) a
      • If you want more, you have to either

        * use more spectrum (aka bandwidth)
        * increase signal strength
        * decrease noise

        But you can use more spectrum while still using the same range of frequencies, by finding a way around interference of signals at frequencies close to eachother. From the blurb about OFDM it seems that's what they're doing. Combining different signals at frequencies very close to eachother in such a way that they interfere in the air, but can be picked apart again at the receiv

  • Surely can't be long (Score:5, Funny)

    by gonerill ( 139660 ) on Wednesday September 29, 2004 @10:31PM (#10390586) Homepage
    It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"


    Not long at all. And about ten minutes after that, the two RIAA agents will enter the carriage with an alsatian, escort you off the train at the next station and you will never be heard from again.

  • Raw stats on movies... (Score:5, Informative)

    by strredwolf ( 532 ) on Wednesday September 29, 2004 @10:32PM (#10390588) Homepage Journal
    Okay, let's get some raw movie stats. Assume plain RGB pixmap flipping at 24 frames per sec, movie size. That's 720x480, three bytes per pixel.

    That's about 1 Megabyte a second, or 8 Megabit. Add another 256 Kilobits/sec for audio (Mp3, Vorbis, or AAC, anyone?) and that's 10 Megabit and change.

    Isn't Divx compression good?

  • Tesla predicted this already? (Score:4, Interesting)

    by brxndxn ( 461473 ) on Wednesday September 29, 2004 @10:35PM (#10390620)
    Didn't Tesla predict infinite bandwidth in the wireless spectrum by combining frequencies in certain combinations? ..

    • Huh? (Score:3, Informative)

      by div_B ( 781086 )
      Didn't Tesla predict infinite bandwidth in the wireless spectrum by combining frequencies in certain combinations? ..

      Isn't the range of frequencies available for combination itself the bandwidth?
      Wider band of frequencies => sharper pulses can be formed by fourier synthesis => more 1s and 0s transmitted in a given time-frame?
      • That's pretty much right:
        A wide bandwidth translates to a narrow pulse in the time-domain.

        OFDM(orthogonal frequency division multiplexing) is a spread-spectrum technique meaning it spreads its energy(the data) out over a wide range of carrier frequencies -- the total power output required is actually less than by using a single carrier.

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

          by _defiant_ ( 120560 ) <stephen.butler@gmail.com> on Thursday September 30, 2004 @01:57AM (#10391620)
          OFDM(orthogonal frequency division multiplexing) is a spread-spectrum technique meaning it spreads its energy(the data) out over a wide range of carrier frequencies -- the total power output required is actually less than by using a single carrier.

          It's even smarter than that! Your little rect in time domain is an inf. sinc in the frequency domain. Of course, after a certain length it dies down to a negligible strength (call this point B). If you wanted to modulate another pulse, to guarantee they will both be exactly recoverable you need to modulate the new pulse up to 2B.

          OFDM basically take advantage of the fact that the signal is digital. Instead of modulating the next pulse at 2B, you modulate it so that the next pulse is centered over the first zero crossing of the first pulse. Normally, this would cause horrible aliasing, but since you know the shape of your input data, all you care about are the values at the origin and the zero crossing. You don't care about recovering the two original signals exactly, the value at the origin and the first zero crossing give you enough information to reconstruct them. Aliasing be damned!

          This takes advantage of the fact that simpler data is more resistant to noise. If you know what you're sending is a 1 or 0, then the waveform can be horribly degraded before it makes a difference. Contrast this with simple voice data, where a deformation in the wave can't be repaired (you don't know what it should look like). In this case, your encoding scheme introduces noise it knows doesn't matter in order to save bandwidth.

          Of course, this is also a form of quadrature multiplexing, which lets you send two signals at the same carrier frequency but differentiate them based on the phase. So that gives you twice the transfer amount you'd normally get above.

          (yes, I'm in a communications theory course right now)

  • Okay, but how does that work - is that 360Mbps per cell, or per connection per cell? Big difference there if it has to be split up for each user on a cell.

    Oh, and if you're gonna dream, forget about the laptop - watch the movie on some LCD glasses or something. :)

  • Press Release (Score:5, Interesting)

    by erick99 ( 743982 ) <homerun@gmail.com> on Wednesday September 29, 2004 @10:38PM (#10390630)
    When you get to this paragraph . . .

    Certain statements in this release, other than statements of historical fact, may include forward-looking information that involves various risks and uncertainties. These may include, without limitation, statements based on current expectations involving a number of risks and uncertainties related to all aspects of the wireless communications industry.

    . . . you can be pretty confident that you are reading a press release. This was written by the company that owns the equipment used in the test. This is essentially an advertisement.

  • Is that all? (Score:5, Funny)

    by mikeophile ( 647318 ) on Wednesday September 29, 2004 @10:38PM (#10390631)
    That's a double sided DVD in 3 minutes.

    I'm sorry, but if the DVD takes longer to download than it takes the microwave to heat a HotPocket, I'm still going to be annoyed.
    • I'm sorry, but if the DVD takes longer to download than it takes the microwave to heat a HotPocket, I'm still going to be annoyed.
      You could always buy a 250 watt microwave.
    • yeah, but you could immediately stream that DVD. Just try THAT with a hotpocket!
    • Don't worry at a certain bandwidth you will be able to hold the burrito between your laptop and the general direction of the wi-fi tower and cook the burrito while you wait!
  • SO why am I still paying $30 dollars for a lucky-if-I-can-get-300kbps-all-the-time-connection and calling it broadband ?
    • Because your cable company still has to pay off the bonds it issued in the 80s to put the cable in the ground in the first place.
    • When you ask? WHEN?!? NEVER! That is unless you want to give your firstborn unto the infinitely evil wireless carier who's name should not be uttered *cough* verizon *cough* and agree to be indentured to them for a few hundred dollars a month for a few years.

      EVDO won't be the last big speed-hop from them for awhile. I'm pretty certain that within the next ~5 years they'll muscle LG and Moto into making handsets and NICs based on some new tech and declare CDMA 1X/EVDO dead. Then the 1 - 2 years of "convein

  • Raw Speed Doesn't Mean Much (Score:5, Insightful)

    by femto ( 459605 ) on Wednesday September 29, 2004 @10:44PM (#10390659) Homepage
    It's the 'spectral efficiency' (the number of bits per second per unit of bandwidth) and the ability of the receiver to reject other users signals that is important.

    It is relatively easy to do 360Mbps given the whole radio spectrum to play with. It's a lot harder when it is necessary to coexist with all other users or a limited bandwidth is available.

    The article doesn't give such information so Siemen's acheivement may be impressive, or then again it may not.

  • Maybe in Europe (Score:3, Interesting)

    by Bruha ( 412869 ) on Wednesday September 29, 2004 @10:47PM (#10390679) Homepage Journal
    It'll be harder to realize any type of high speed wireless that is affordable here in the US. We'll have to see what WiMax eventually does.
  • So I'm gonna shoot all my Blockbusters in Black and White for an even faster download.

  • except for... (Score:4, Funny)

    by Anonymous Coward on Wednesday September 29, 2004 @11:00PM (#10390750)
    > It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"

    Well, except for the Americans, who will get it 15 years after everybody else does, but claim they invented it.

  • Hmm, and this helps us how? (Score:5, Interesting)

    by goneutt ( 694223 ) on Wednesday September 29, 2004 @11:06PM (#10390774) Journal
    Since almost all servers are not connected to better than 100Mbps (I haven't been on that side of the eq since 1998 so I'm making assumptions, 'scuze me if I'm wrong) , network congestion, etc, I never see the full bandwidth of my 4Mbps line used on one task. 360Mbps might make for an impressive show of ability, but that has limitations at other bottle necks.

    The only immediate application I can think of for is setting up temporary offices where you don't want the expense of cabling, but even then you quickly fill the RF bandwidth.
    • Although there's no practical value in having 1 of a group of bottlenecks relaxed, there's still value in relaxing it. Innovation in leaps or babysteps is innovation nonetheless.
    • Wireless is a shared medium, so that 360 Mbps is divided by the number of users. The point is that it becomes possible to support more users in a given amount of bandwidth at a reasonable speed, not that a single user could get a (generally unnecessary) higher max speed.
  • I'm moving to Munich, Germany!
  • "It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"

    Why would you leave the house in the first place?

  • Yes it can (Score:3)

    by Halvard ( 102061 ) on Wednesday September 29, 2004 @11:27PM (#10390881)

    It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?"

    Especially in the US it can take quite a while to deplay. Since this likely will end up with service providers, you surely don't expect that they would offer the maximum bandwidth for short change do you? Likely, it would be metered or used for last mile, since interconnecting landline circuits would be a lot slower.

  • It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?

    Not those of us living in the US. Surely you don't expect this technology to come to America any time soon. We are always the last to get the really cool stuff.
    • Try living in Africa for a while (I'm in South Africa) and then talk about always being the last to get the really cool stuff.

      We only got ISDN a few years ago, and that isn't widely distibuted yet. Broadband, via ASDL and satellite linkage, is a distant dream for most people (heck, for most of our rural population, a telephone and electricity is a distant dream :( ).

      I agree, the US is probably less technologically favoured than Europe, but from our perspective, everyone else, North America, Europe, Austra
    • Heh, not true actually, unless Raleigh [nextelbroadband.com] has suddenly moved location to West Africa?
    • Well, you can't have it all - at least you still get the coolest cluster bombs, assault guns and chemical weapons.

      k2r

      (some of my best friends are American :-)

  • Cisco did this 6-7 years ago (Score:4, Informative)

    by dangermen ( 248354 ) on Wednesday September 29, 2004 @11:33PM (#10390913) Homepage
    I remember Cisco offering a product six or seven years ago that did vectored orthogonal frequency division multiplexing. It could do 45mbps non-line of sight as point-to-point or as a unidirectional 28 channel T1'looking setup al la Cisco 2600 WIC Cards. I wonder how this is different.

  • Heute 360Mbs.... (Score:3, Funny)

    by Anonymous Coward on Wednesday September 29, 2004 @11:34PM (#10390920)
    MORGEN DIE WELT!!!!!!!

    crowd rises in unison, tosses old telco equipment on raging fire...

  • Not Max enough (Score:5, Interesting)

    by Doc Ruby ( 173196 ) on Wednesday September 29, 2004 @11:40PM (#10390941) Homepage Journal
    "In the train" sounds good for 360Mbps, because each metal container will hold about 200 people max, which is at least about 1.8Mbps each. For Munich's 1.5M people, that's about 240bps, using a single hotspot. Such a system is better deployed by the city itself, for its mobile services. That doesn't feed bandwidth directly to the citizens, but rather to teams of people, like a fire engine with a WiFi gateway for WLAN.

  • I doubt it.... (Score:2, Insightful)

    by novalogic ( 697144 )
    Doubtful, if the current trends in American markets keep up, it would be a decade easy before we get to this point. If you don't belive me, just look at this link [slashdot.org] it's more profitable for a company to offer slower service, not upgrade, and charge by the Kilobyte, rather then broadband us.

  • OFDM is old technology (Score:4, Informative)

    by Bored Huge Krill ( 687363 ) on Thursday September 30, 2004 @12:58AM (#10391394)
    This article seems to imply that OFDM (used in 802.11a and 802.11g) is somehow a "new" technology. It isn't. It turns out to be quite hard to find the oldest use of OFDM, because it appears to have been used in military systems which were classified long before it became publicly known. However, the oldest published document I know of is a patent for orthogonal frequency multiplexing, filed in 1966 (granted in 1970) by Robert W. Chang of Bell Labs. I don't remember the patent number off the top of my head. :-) The real change to get enormous data rate with increased spectral efficiency (which you'll really need...) over a useful range is MIMO (multiple input multiple output) which uses spatial diversity to effectively create many spatially diverse (mostly) independent communication channels simultaneously on the same frequency channel. Methods combining OFDM and MIMO make up all of the front running proposals for the future 802.11n standard currently in the works.
    • OFDM may not be new as a technology, but what is "new" is the possibility of implementing it in consumer-grade devices, made possible by the more and more powerful and ever cheaper DSP devices.
      Of course not "new" in the sense that it should appear in a news article today, but practical use of OFDM at megabit rates has only been possible for a couple of years.
  • Did anyone else read that as "ornithological [reference.com] frequency division multiplexing (OFDM [com.com])" at first, or is it just me?

  • OFDM is already used for high bandwidth streaming! (Score:3, Informative)

    by Goth Biker Babe ( 311502 ) on Thursday September 30, 2004 @03:43AM (#10392013) Homepage Journal
    Last night, as I sat in bed, I channel hopped and ended up watching BBC 3 on my bedroom TV which receives it's signal through a small set top antenna. In fact that TV can pick up over seventy TV and Radio channels through that antenna.

    Why? Because DVB-T, the terrestrial form of the DVB digital television standard uses OFDM to ensure signal reliability. There are roughly eight TV channels per multiplex at PAL resolution which is quite a bandwidth. So how is this new?
  • "It surely can't be long now before we're all streaming the latest blockbuster movies to our laptops on the commuter train home?" If you have ever used a german train you wouldn't have made this comment. Although there are relieable and fast, a mobile connection is the last thing you can hope for. It feels a bit like no longer being in germany once you entered a train. So no matter what connection speed, expect gaps from 5 sec to 15 min in your movie... wait than a David Hasselhoff movie can even be fun...
    • Yeah, but at least you get somewhere to plug in your laptop! (Credit to Virgin for finally bringing this much-needed feature to the British rail network... by buying German trains!)
      • Oh well, at least you have some plugs (4 per waggon), which helps at least. But if you consider that Siemens is also building the trains, you wonder why they can't manage to estabish a repeater or a amplifier in the trains, particular the new ICE are really bad if it come to a mobile connections.

        • It's true, they should. (But this will never happen on the British rail network... on the London Underground, yes it's planned, but otherwise...)

          As it goes Virgin (in the UK) are doing something for data (given that they operate long connections between hi-tech destinations, connecting, for instance, Yorkshire with Newcastle, Edinburgh and Southampton) with wireless [virgintrains.co.uk] on board... sadly only in first class - academics aren't allowed to travel first class :(

        • Oh well, at least you have some plugs (4 per waggon), which helps at least. But if you consider that Siemens is also building the trains, you wonder why they can't manage to estabish a repeater or a amplifier in the trains, particular the new ICE are really bad if it come to a mobile connections.

          Actually they do manage. The new (=since 2000) ICE3 trains actually have repeaters in some sections of the trains (and sockets at every seat pair). That they don't have repeaters everywhere is more due to what Deu
  • the story never changes, only the numbers. Actually, the number don't even change, just the units of measurement.
  • Mobile net is all very good, but will this actually be affordable by the average person? Most households are fine with paying a monthly fee in the region of around 10 - 25 quid for either unlimited adsl or old dial-up but mobile phone companies seem to think that they have to rip us off or else they don't get to eat! GPRS is still charged in cave-man prices, If anyone is prepaired to offer a proper mobile internet service, flat-rate at the same monthly fee as adsl then i reckon most people would drop their
  • "I've got 500Megabit wireless on my laptop!"
    "So then why are you carrying around that long ethernet cable?"
    "It doesn't go to the laptop, it goes to the transmitter -- It's only got a 6 inch range.

    (something like that actually happened at one computer lab where I worked.. They tried getting a cordless phone to use in the lab, but all of the computers generated so much interference that it only had a 3 foot range, so we ended upsing a regular phone with a 40 foot extension cord)

    In this case, I realize

Slashdot Top Deals

Any program which runs right is obsolete.

Close