Please create an account to participate in the Slashdot moderation system

 


Forgot your password?
Close
typodupeerror
×
Technology

The Phony Conflict:802-11 & His Pal Bluetooth 148

Posted by Hemos from the making-wireless-really-work dept.
LupeROD writes "Here's a story that shoulders the responsibility of trying to convince us all that the spectrum wars between 802.11 and Bluetooth are bogus and the truth, be it obscured, is that 802.11 and Bluetooth are really compadres.""
This discussion has been archived. No new comments can be posted.

The Phony Conflict:802-11 & His Pal Bluetooth More

The Phony Conflict:802-11 & His Pal Bluetooth

Comments Filter:

  • Next Week.. (Score:1, Funny)

    by TheDick ( 453572 )
    We'll be seeing stories about IPX/SPX and TCP/IP interfering....

  • this is not new information (Score:5, Insightful)

    by Fnkmaster ( 89084 ) on Sunday October 28, 2001 @02:49PM (#2490016)
    This article rehashes what we already know - the purposes of Bluetooth and 802.11b are fundamentally different - Bluetooth supports what he calls a WPAN (Wireless Personal Area Network) and 802.11b is for WLANs.


    This article does not address the _real_ issue that I have heard quite a few people bring up - that the intentions of the technologies and their use cases are orthogonal, but they use the same chunk of bandwidth and the nature of their frequency usage does not play nicely with each other.


    I don't know the exact details, but I've used older FHSS and DSSS WLAN technologies as well as 802.11b hardware and I believe it has something to do with the fact that one of Bluetooth or 802.11b is direct-signal and one is frequency-hopping and they therefore tend to obliterate each others signals intermittently. I can't personally testify to this, as I only have experience with 802.11b, but I will tell you that with a 2.4GHz portable phone that my mother bought and the old Proxim Symphony (FHSS if I remember correctly), the interference was a real problem in a practical situation. The 2.4GHz phone could not be used while sitting at the computer desk where the Symphony antenna lived, or the computer would lose connectivity. I finally ditched the wireless network in that apartment and moved to HPNA 2.0, a fabulous solution if your physical configuration doesn't allow good 2.4GHz transmission.


    So yes, we would all love to have both Bluetooth and 802.11b work together in perfect harmony and we accept that they don't really compete, and there have been several /. articles with many postings to that effect. The real question is how do we make a technical solution to get the two standards to play nice with each other, if indeed the problems are as significant as I imagine they will be (based on anecdotal reports from others and based on my personal experience with 2.4GHz technology).


    • I don't know the exact details, but I've used older FHSS and DSSS WLAN technologies as well as 802.11b hardware and I believe it has something to do with the fact that one of Bluetooth or 802.11b is direct-signal and one is frequency-hopping and they therefore tend to obliterate each others signals intermittently.

      Nice theory. 802.11B can be either depending on how you set your card and station up, so this couldn't be the only problem. (Though every 802.11B installation I've ever see uses FHSS.)

      Not that this invalidates your point that the two still interfere with each other. :^>
      • As I said, I am not really sure exactly why, given that these should be relative durable mechanisms for handling frequency usage. I'm just stating a) what I observed with my 2.4GHz hardware, which was admittedly a while back and was a phone and an old Proxim Symphony WLAN rather than Bluetooth+802.11b, and b) the anecdotes I have read on /., which are admittedly not scientific in nature.


        I would love to read some real results of testing the two together and seeing if there are problems in certain configurations or if there are universal problems, or if my fears are unwarranted. But I do think that points a and b above provide enough justification to ask the question: do Bluetooth and 802.11b play nice with each other or not, and if not how can we make them play nice?

      • Actually, 802.11b is a DSSS-only technology. 802.11 specified both a FHSS and DSSS modulation layer running at 2Mbps max. 802.11b is an extension to 802.11 which specifies 5.5Mbps and 11Mbps speeds for the DSSS modulation only. If you can select a channel, as you can for all 802.11b gear, than it is not FHSS. After all, if you are frequency-hopping, it doesn't make much sense to specify a single frequency, does it?

        If you are doing much 802.11 work, I highly recommend IEEE 802.11 Handboook A Designer's Companion by Bob O'Hara and Al Petrick. It explains all of this is good detail, while still being easy to read and cheap compared to buying the actual standards from IEEE and trying to read them.

    • Re:this is not new information (Score:5, Informative)

      by hattig ( 47930 ) on Sunday October 28, 2001 @03:05PM (#2490067) Journal
      This article does not address the _real_ issue that I have heard quite a few people bring up - that the intentions of the technologies and their use cases are orthogonal, but they use the same chunk of bandwidth and the nature of their frequency usage does not play nicely with each other.

      Did you read a different article to the one I read? It does mention it, and describe why it ISN'T an issue, and that both these specifications live quite happily together.

      2.4GHz is an open area of bandwidth - you have to expect interference. Home RF, DECT, Bluetooth, 802.11. Hence these technologies are designed to deal with interference, even high interference.

      The use of one of the technologies in an area with the other technology only raises the noise level a bit. In fact, interference for each of these technologies is not caused by the other technology being present, but just by high levels of general interference (e.g., using it inside a nuclear reactor).

      • I read that as the author brushing off the issue. I am commenting based on anecdotes I have heard from those who have seen the two technologies used together and based on my very real experience with 2.4GHz which proved to me that in older incarnations, pre-802.11b technology did not deal well at ALL with interference.


        So yes, I understand that theoretically FHSS is designed to make this a non-issue by avoiding bad (used) frequency ranges, I'm asking a question about the reality or practice of using the two together, not about the theory which the author appeals to as an argument by authority. I think I have a valid basis for at least ASKING the question, whether or not it turns out to be a real issue.

      • I think this whole situation in one in which theory doesn't mesh with practice. The technologies in question may be capable of dealing with high interference but in my experience (and the experience of the original author you are responding to, and seemingly many others) these devices tend to stomp all over each other making all of them within a typical house-radius often unusable.

        From (the admittedly small amount of stuff) I know
        about these wireless technologies, there are supposed to be built-in checks to deal with this interference, but in practice it would seem like very many vendors are not bothering to implement these and their devices, either at the hardware or driver level just cannot deal with any meaningful amount of interference.

        I've personally had to pull my 802.11 network due to proximity of cordless phones and even a logitech wireless mouse/keyboard. Maybe the card vendor (DLINK, fwiw), is at fault -- not the underlying protocols, but in any case it is a very real problem that many people are running into in practice.
        • I've heard of phones failing, and wireless mice going bonkers. If that's your problem, this isn't because 802.11 can't handle interference, it's 'cause the mouse and the phones can't. Were any of these devices using Bluetooth? If they were, you didn't say. If they weren't, their failure is irrelevant.

          • It was the 802.11 device that was failing. The phone would always work fine, but whenever the base or receiver for said phone was within 100-200 feet of any of the 802.11 devices, the 802.11 network would go offline completely. Shutting the phones off or removing them from range would bring it back, nothing else would.

            None of these devices were using Bluetooth. The point I was trying to make is broader than Bluetooth vs 802.11, it seems to be a general lack of worrying about playing-nicely-with-others that device manufacturers using the same frequency bands suffer from. Even if these protocols have methods of dealing with interference (in my experience) they seem not to be implemented very widely.

            • For what it's worth, I have the Lucent Wavepoint 802.11b system base, and the Siemens 2-line, 8handset 2.4G phone system base sitting 5 inches apart and they work fine, but the X-Cam 2.4G video is completely useless even across the house from those base stations with the X-10 xmitter & receiver 20' apart if either the phone or 802.11b is powered up.

              Devices that don't play nice can ruin things for those that do, and some like the X-10 unit that don't play nice assume that it's the only 2.4G device within range.

              BTW,don't you just hate pop-under ads like X10.com uses? That kinda thing drives people to ad-blocking software which is bad for everyone in the long-run...
        • Devices that operate in unlicensed bands must accept interference from all sources. Which means that even in my own house, I coudl operate the same system (802.11b, cordless phone, etc) and have all kinds of problems, but my neighbor who owns the same system might be jsut fine. The problems could come from the Metricom antennas (or whomever might be operating today) outside my windows because they happen to be operating on that unlicensed band.
          • Yes, it must accept interference, but it doesn't have to WORK.... That's been a plague on all unlicensed band devices from garage door openers, old cordless phones, baby monitors, etc. all the way to 802.11b.

            What's really needed is a chunk of frequency with a single spec. (protocol) that ALL devices operating on those channels are REQUIRED to adhere to.

            Right now, all sorts of crap runs in the 900 and 2.4 ranges all using spectrum as it pleases - a literal garbage dump of protocols. It's a wonder ANYTHING works.

      • Symbol and Aironet/Telxon (now Cisco) did a lot of research into this, and found that they do NOT coexist nicely. Yes they are all in the same 2.4Ghz area, but they are not designed to cooperate with other 2.4Ghz traffic. They are designed to ensure their own traffic gets through even with high interference. In the 802.11 spec, FH and DS coexist reasonably well, but the thing which causes the problems with Bluetooth is that its hop frequency is 100 times faster (IIRC) so it responds faster and breaks 802.11.
        I have confirmed this myself on various occasions, and for most clients have proven that 802.11 should be used exclusively. Things may be a little different now we can use the 5Ghz band (and get much higher speeds) for 802.11 and have Bluetooth sitting on 2.4Ghz, but there is not enough of an advantage to do so - it just makes life more difficult as you need to support both forms of comms, and sort out security for them both.
      • Yes, the FCC specifies that the device has to expect interference. It does not specify that it has to keep working! I've taken an FHSS connection off the air by trying to do a site survey with 802.11b gear in the same room. I've seen 802.11b gear garble up the image coming out off a 2.4GHz wireless camera. Most 2.4GHz phones will completely overpower 802.11 gear. I've got a 2.4GHz spectrum analyzer, and the amount of radiation spit off from the 2.4GHz phones has conviced me that you do not want one near your head, much less near your WLAN. The FCC in no way specifies that all this stuff has to keep working when they are all in the same room. I think they just have to not permanently break when they get interference. Probably as long as they don't catch on fire, the FCC will approve it.
        • So in the end, using 2.4GHz for all these different things is a bit of a crap idea? Hence 802.11a moving to 5GHz to get some fresh air... (and extra bandwidth, etc).
          • 802.11a is great until everyone else moves there too. But it's not all bad. It's not hard to find out what frequency most devices use. And since the range is so short on all of these, it's not hard to do what you want and still have things work. I tend to use 2.4GHz for 802.11b gear. For a cordless phone, 900MHz still works fine. IR works fine for Palm syncing and such. You can't really expect to buy every 2.4GHz toy on the market and get them all working well in one room. But like I said, the range is small, so you can be the 'FCC' of your house and plan accordingly without too much bother.
    • By the way, another poster posted this link which partially answers my question: http://grouper.ieee.org/groups/802/15/arc/802-15-2 list/pdf00001.pdf [ieee.org].


      It's at least enough of a real concern that people are studying it in an academic environment and presenting results on it to IEEE forums.


      I also found this one, which is substantially more informative and complete:
      http://www.wi-fi.com/downloads/Coexistence_Paper_I ntersil_Aug18.pdf [wi-fi.com]. This is a good discussion, which seems to conclude that yes, they do interfere to an extent, but performance degradation is graceful, though it apparently depends greatly on the amount of usage Bluetooth is getting (density of Bluetooth traffic in the locale of an 802.11b access point).

    • My telephone is a 2.4GHz Siemens Gigaset. My X10 gear uses the 2.4GHz frequency to transmit audio/video (That does conflict with my phone)... The 802.11b wireless Networking adapters also operate in the 2.4GHz frequency and so does Bluetooth. I wouldn't say that it has much to do with Microwaves Ovens... You may not to use 2.4GHz gear if you like but your neighbour may (and my phone works in the ground floor even tough I live in the 8th floor... (If I am outside of the building as7 layers of concrete is too much but some 3-4 are still ok...))

      If that was from 2.4 to 2.499 it would be quite a bandwidth, but if that is from 2.43200 to 2.43201 it ain't that much... Got it?
  • There's nothing really surprising in this article. Bluetooth is designed for (and marketed as) a solution for short-range communication between "simple" devices, while 802.11 is a wireless Local Area Network standard for computers.

    Sure, you could have a conflict between the two technologies, especially where the definition of "computer" gets a little vague. But ultimately, they're different sorts of technologies, designed for different uses.

    I don't think anybody is seriously going to pursue a home networking solution based on Bluetooth, for instance...

  • Excellent Resources (Score:5, Informative)

    by webword ( 82711 ) on Sunday October 28, 2001 @02:52PM (#2490027) Homepage
    These are my favorite resources on this subject...

    Bluetooth Resource Center [palowireless.com]

    A Businessman's Comparison of Bluetooth and Wi-Fi (802.11b) [palowireless.com]

    Empirical Study for IEEE 802.11 Aand Bluetooth Interoperability [ieee.org] (PDF)

    Wi-Fi will not make Bluetooth obsolete [wallstreetweb.nl]
  • If you check out the URL, the real competetor here is this new technology.."WirelessBuds"

  • WPAN? (Score:2, Insightful)

    by maniac11 ( 88495 )
    Okay... I realize that we live in a seriously acronym heavy society, but WPAN?!

    Seriously though, the article in question seems to underline the problems with Bluetooth:

    The data rate for Bluetooth communications is about one-tenth that of IEEE 802.11

    The reach of IEEE 802.11 is about ten times that of Bluetooth technology

    Bluetooth uses packets designed specifically for Bluetooth transports

    So, we're talking about a networking protocol that is slow, only works in very close proximity, and is an additional, propietary packet structure. Great...

    802.11 works for both "WLAN" and "WPAN" applications... why bother addressing two protocols?

    • Re:WPAN? (Score:3, Insightful)

      by hattig ( 47930 )
      802.11 works for both "WLAN" and "WPAN" applications... why bother addressing two protocols?

      Bluetooth uses a lot less power than IEEE 802.11. This makes it suitable for use in your next keyboard and mouse, your PDA, etc. You don't want to replace a battery in your keyboard every week! Nor does a keyboard or a mouse need an IP address (yet! :) )

      Also, Bluetooth support adds $5 to the cost of a device today. In a years time that will be $2, in two years time $0 as it will be a standard integrated part of PDA CPUs, etc. The chips are small, easy to integrate, etc. 802.11 adds a lot more to the cost of the device ($20+), uses up power (to transmit further) thus requiring more/better batteries (more $$$).

      We all know the solution is wireless electricity distribution.... :) Tesla didn't finish his work in this arena though, and nobody has looked at it since or cares.

      • We all know the solution is wireless electricity distribution.... :) Tesla didn't finish his work in this arena though

        Great idea. Um... why are my CDs sparking? ;)

      • Bluetooth is noncompetitive (Re:WPAN?) (Score:5, Informative)

        by isdnip ( 49656 ) on Sunday October 28, 2001 @04:10PM (#2490223)
        Well, no. Bluetooth does NOT add $5 to the cost of a device today, except perhaps for very large values of $5. That was the goal, but today it costs quite a bit more. It needs critical mass to come down that low, and critical mass is proving elusive.

        Bluetooth's advantage is low power, making it suitable as a "cordless" technology. But 802.11 can be run with less power than the legal limit, again invading Bluetooth's turf. That's probably Bluetooth's Achilees Heel -- it's not that much better than 802.11 at what it's better at (low power).

        Further putting a nail in Harold B's coffin is the actual Bluetooth spec. I've looked at it and IT STINKS. They have a preposterously complex protocol stack for doing simple things. They literally take the packets, serialize them, put in an RS-232 emulation protocol (control pins & stuff), stick Hayes AT modem commands atop that, and run packets atop THAT! Truly demented. Work done by a committee that had NO FREAKING CLUE what they were doing. That as much as anything explains the lack of interoperability. (802.11, at least, is easy to use, like other 802-family protocols.)
        Which is too bad, because a $5 Bluetooth chip with micropower battery drain really would complement 802.11 and other things. But that's not what the corporate sponsors put out.
        • They literally take the packets, serialize them, put in an RS-232 emulation protocol (control pins & stuff), stick Hayes AT modem commands atop that, and run packets atop THAT!

          Thankyou very much. That's all I need to know about Bluetooth.
        • This (if it's reliable :) answers my bluetooth issue: why do I want a wireless networking protocol that *doesn't* talk to my home network? (ans: I don't)

          Why do I want another wireless card in my laptop or on my home network router, if I can stick with the WLAN stuff I have now? And don't quote the "voice" business from the article, I'm not in the habit of talking into my PDA, and voice-over-IP routes better anyway. Sure there might be home-intercom applications, but voice-over-ip at 10x the speed should handle that nicely :-).

        • This is not true. What you described above is the RFCOMM layer. It emulates RS-232 in order to acheive backwards compatibility with appilcations having a serial interface. You don't need RFCOMM in order to send a packet, in fact you don't need anything but the Host Controller Interface (HCI). I've programmed the Ericsson Bluetooth module with HCI as the top level in the stack.

          Mikael.
          • Exactly. And if you do your own chip, you can do whatever you want, so you can skip the bigger part of the HCI (the abstraction layer) and interface between your profile/presentation layer and the Link Manager and L2CAP layers.
            As you said, the only reason you would want to mess with RS-232 is if you had an existing product that you wanted to Bluetooth-enable very easily.
            Also: There is no specified physical transport for HCI, but USB and RS-232 are suggestions only.
        • >Well, no. Bluetooth does NOT add $5 to the cost >of a device today, except perhaps for very large >values of $5. That was the goal, but today it >costs quite a bit more. It needs critical mass >to come down that low, and critical mass is >proving elusive.
          Well, TI just announced around a week back that the have come up with a BT chipset with a BT controller which costs $5.And if U don't require BT controller,it costs $3.So here goes ur first objection. The problem is that the early movers in the technology spent a whole lot more on the h7w and s/w so they r gonna charge you for that.But as of now, it has become cheap.
          >Further putting a nail in Harold B's coffin is >the actual Bluetooth spec. I've looked at it and >IT STINKS. They have a preposterously complex >protocol stack for doing simple things. They >literally take the packets, serialize them, put >in an RS-232 emulation protocol (control pins & >stuff), stick Hayes AT modem commands atop that, >and run packets atop THAT! Truly demented. Work >done by a committee that had NO FREAKING CLUE >what they were doing.
          Well dude, I don't know why you said that...trying to sound more knowledgable than U really r about BT I suppose. What you r referring to is RFCOMM, the topmost layer which is required by applications which run on old serial ports, so don't expect it to be faster than a serial port. But for BT aware applications, you don't need to use serial ports and as has been pointed out, U can just use HCI or a combination of HCI and L2CAP.
          >That as much as anything explains the lack of >interoperability. (802.11, at least, is easy to >use, like other 802-family protocols.)
          Interoperatabiliy is one thing which caused the delay in BT in the first place. But to sort this issue, they have got unplugfests. And besides, if the product is certified to be bluetooth compliant( yes, they have an obligatory certification program), you can be sure that you won't have interop problems.
      • wireless electricity distribution.... :) Tesla didn't finish his work in this arena though

        I assume the :) means that the author knows what he's talking about, but in case anyone else doesn't get it, he's talking about a Tesla coil. It's a rather amusing toy. To get a general idea, imaging running your microwave oven with the door open :)

        The energy isn't directly dangerous to humans like microwaves, but in some situations they can conduct deadly house current through open air and you're as cripsy as if you stuck your hand in a wall socket.

        Aside from that, there's quite a few fun stunts you can do with them. You can hold a florescent light in your hand and it will light up. If you're real careful you can even "touch lightning".

        A main problems with using them for wireless electricity distribution is that they don't have much range and most of your energy gets broadcast out into space. Oh yeah, and I don't think it would be too healthy for your electronics to get anywhere near them :)
      • IANAEE, so what's the feasibility of an 802.11lp (low power) standard that can talk to an 802.11b device (within 10 unobstructed meters)? Doesn't 802.11b have fallback speeds, slower than 11Mbps, for when the signal is too weak? Wouldn't this be a way to get the benefits of Bluetooth (low power) without having to use the protocol, which a lot of people seem to detest with a vehemance usually reserved for the Yankees?
      • Yeah, like people who are afraid of magnetic fields around high power lines are going to tolerate high-power masers (microwave analog to lasers) aimed at their houses to provide electricity.
    • Your points are correct, but you ignore one extremely important other point - Bluetooth has MUCH lower power requirements. A PDA, pager, phone or wearable computer can't maintain a reasonable battery life and use 802.11, whereas it can do Bluetooth much more feasibly. This alone is the reason Bluetooth is useful.
    • You won't see cellphone manufacturers building cellphones with 802.11b anytime soon - they're all going down the Bluetooth road. That, by itself, will probably drive many bluetooth applications/products.
    • And that's why I avoid USB networking equipment even though I have other USB devices and will continue to buy them. I also don't connect my internal hard drives or monitor with USB. Bluetooth is for connecting devices, not transfering data.
      • If you're just interested in connecting devices, not transferring data to/from them after connect, you might look into Plain Old String Technology. And what's the intermixing of Bluetooth and USB for? *Confused*.
        • He's comparing Bluetooth and USB because they both "serialize" the data with "proprietary" protocols. Of course, the USB protocol isn't considered "proprietary" because it's the "standard" nowadays...

          The author is basically stating that the techonology *should* be used for simple device connection, and not complex network connections..

          I think..

          :)
    • The lower reach of bluetooth is somewhat of an advantage security-wise. do you really want your laptop to sync with every cell phone that walks by?

    • WPAN is a system for torturing terrorists with erl scripts, I thought everyone knew that!
    • Try putting WLAN in ur mobile and PDA. When U r always out of battery after 1 hour, U will know why you should be using Bluetooth and not WLAN

  • Phony my butt! (Score:1, Redundant)

    by baptiste ( 256004 )
    This article states the obvious - 802.11b and Bluetooth target different audiences, etc. No kidding. However, they ARE in conflict. Numerous articles and tests have shown that 802.11b throughput and range drops like a stone if your 802.11 device happens to be near a bluetooth device since they share the same spectrum. So what do you do if you have bluetooth devices all over your cube and the guy next to you wants to use his 802.11b PDA? He'll most likely have serious trouble if he's not near the access point.

    I personally think Bluetooth is a joke. Remember how USB was supposed to eliminate all the wires to our PCs? You know - one or two USB cables to the box. The monitor and keyboard would have USB ports on them so you could plug other stuff into them, etc, etc. But it hasn't really happened. Yes, USB is making inroads but VERY slowly and NOT because of bandwidth issues. USB 2 will be nice but its not gonna speed up adoption of USB. Bluetooth will be similar. WHo cares if your PDA uses a serial or USB port or wireless to talk with your desktop? Personally? I'd prefer to have wires for security (do I want my contacts and calendar broadcast to to my cubemates?) Thanks, I'll pass. Printers? Maybe - but serisouly, use a thin, easy to route USB cable.

    I don't need a pico net on my desktop. I need a smartly designed setup where wires run a minimum distance because defvices can be chained, etc. My mouse should plug into my keyboard (duh!) instead of running along side its wire. (Appel got that one right) My keyboard should be able to plug into my monitor. My camera - go to the monitor or keyboard. Speakers? Whatever. You get the point.

    I just don't see the killer apps that will make Bluetooht more than an annoyance.

    • If 802.11b can't handle interference, that seems to be a problem with the 802.11b technology, doesn't it?

      My cordless phone works in 2.4ghz, and it can handle the interference from AirPort. Other technologies should be expected to play nice" and handle interference as well.

      This is a well-written article that clearly articulates what needs to be said. Many got caught up in the Bluetooth hype (and many of those same people are now caught up in the 802.11 hype). What they don't understand is these technologies serve fundamentally different needs; that is, they are solutions to different problem domains.

      As such, comparing the two and determining one to be better is almost always meaningless - it would be like comparing a car and a bicycle for getting around your school's campus. The car doesn't make much sense because of the overhead of starting it up/shutting it off/parking, and the fact that there are few well-defined area to drive in. The car is made for longer-distance travel. A bicycle, on the other hand, is made to go shorter distance, but it can manuever many more areas. To consider the car or bicycle a better OVERALL transportation solution is meaningless, because it does not speak to the specific needs a user has at a given time.
    • The monitor and keyboard would have USB ports on them so you could plug other stuff into them, etc, etc. But it hasn't really happened.

      Yes, keyboards with 2 USB ports on them are available everywhere, and for not much money. I have my mouse plugged into my keyboard. You can also go the Microsoft way and pay more for the keyboard and mouse with the same functionality (like I did). But I agree, USB has not done much for getting rid of cables. My mouse does not have a 2 ft cable because it can assume it is plugged into the keyboard, it has a 5ft+ cable so it can be plugged into a computer. That is why PCs now have tonnes of USB ports in them.

      Monitors with USB support seem to cost a lot more than without USB support though. There is no good reason for this in my opinion...

      To be honest, I don't want to have batteries in my mouse or keyboard, and prefer the cable. For a PDA - it needs to be recharged at some point anyway, so recharge it via USB or Firewire and sync at that time. Scanners and printers are fixed, they don't need wireless capabilities. So the only need for wireless at all is for people with laptops who want to pay $200 for a wireless LAN card instead of $40. Just so they can surf the net in meetings or whatever...

      • I managed to get a monitor with USB(didn't get it because of it)... but the ports are on the back, now that is useless..!!!

        I do intend to get a wireless card when I get my laptop, being able to slap the thing down anywhere is great!...
        However there are other very good reasons for wireless... If you need to traverse, property that is not yours, a road way or just save money by not having to run wires outdoors; Sometimes wireless can be a much cheaper solution especialy when compaired with the cost of profesional wiring..

        (sp:)
      • Monitors with USB support seem to cost a lot more than without USB support though. There is no good reason for this in my opinion...

        There is a good reason for this - bandwidth. Sure you can run 127 devices off a USB port, but the data rate to each one isn't going to be great. Certainly if you must get a USB CD burner, you would want to run it off a different USB node to your USB sound system or scanner.

        I don't know how many USB ports modern computers have, as opposed to the number of plugs you get - any one know how most computers do 4 usb ports?

        Michael
        • Modern chipsets include 2 or 3 USB controllers, and have 2 or 3 ports for each controller. e.g., SiS735: 2 controller, 3 ports / controller = 6 ports, total bandwidth 3MBps

          e.g., KT266A: 3 controllers, 2 ports / controller = 6 ports, total bandwidth 4.5MBps

          However some motherboards actually have an integrated USB hub - was it the ASUS A7V that had this as an option - you could have 7 USB ports off that one (Two controllers in the chipset, 2 ports / controller, one port went to a 4 port hub).

    • Actually, cordless mice are wonderful, and if mine used bluetooth instead of a funky little dongle, all the better.

      I see your point though, but I can see it being useful for more ad hoc, mobile communications...eliminate passwords to access computers...negotiate payment with vending machines...adolescent dating games...transmittal of electronic business cards...keyless entry....
    • USB was never supposed to "eliminate all the wires to your PC", it was supposed to be a low-cost, reasonably fast interconnect replacing the mess of parallel, serial, PS/2, and low-power connections. It has succeeded very well at that. It also makes driver development easier because it standardizes so much more.

      USB2 is a mistake; it has all the cost of FireWire without the functionality. It will probably be widely available, but it won't replace FireWire.

      Bluetooth covers roughly the same space as USB, but it offers wireless convenience. I hope it will catch on and become cheap: the less wires the better as far as I'm concerned. And if Bluetooth is done right, it should be reasonably secure (certainly a lot more secure than the Logitech wireless numbers people buy right now).

  • I demo bluetooth hardware as part of my job. I have a 3Com Bluetooth PC Card along with an 802.11b PC Card. I am able to surf the net, transfer files, etc., over the 802.11b link, and at the same time, I can sync my PC to an Ericsson T39m (with built-in Bluetooth) or print to my Bluetooth Printer. While I've heard stories that range might be a problem while both radios are active, I personally haven't seen any issues.
    • Since you have experience with it, I've got a question:

      How does the bluetooth protocol handle two bluetooth enable PC//Laptops being with in range of eachother. I see two thing happening, people in apartment sideby side typing on eachothers computers. Or just two of you own PC fighting it out. Also if you go bakc to the appartment... couldn't you just sniff your neighbors' typing in there passwords
      (sp:)
      • If you want your bluetooth device available for others to connect to it, you set it's security to "low" or "none".

        If you want to guarantee that you and only you can connect to your cellphone, you go through a process called "pairing". This assures that my cellphone will only talk to MY bluetooth PC Card and not my neighbor's.

        It all depends on the level of security you wish to use on your bluetooth devices.

  • On a related note, 802.11a uses 5.4GHz (Score:3, Insightful)

    by Black Acid ( 219707 ) on Sunday October 28, 2001 @03:24PM (#2490125)
    The new 802.11a uses the 5.4GHz [mwee.com] spectrum, thus avoiding any problems of interference. Presently, 5.4GHz is (sparingly) used by governmental instutions, but the band itself is license-excempt.
    Then there is the 802.11a standard. It is also licence-exempt but operates at 5.4GHz.

  • But Bluetooth does nothing I want to do (Score:5, Interesting)

    by Zeinfeld ( 263942 ) on Sunday October 28, 2001 @03:31PM (#2490146) Homepage
    The big idea of bluetooth appears to be to make my cell phone talk to my laptop. Rather than stick a bluetooth card in my laptop, buy a new $600 cell phone and then try to get the two to talk I would get a GPRS card for the laptop. Calling plans will soon adapt to that use, they have in Europe.

    In the home there are very few devices that I would want to have on a wireless network that do not have an AC cord attached - so power consumption is not a big issue.

    The other problem with Bluetooth is that it tries to define its own stack for everything. The developers appear to be part of some OSI holdout 'IP will go away' group.

    On the security side 802.11b screwed it with WEP, only that does not matter that much because you can still use IPSEC. With Bluetooth the security model is homegrown as is the encryption algorithm. If someone wants to make a name for themselves in the crypto world go hack the Bluetooth crypto.

    The author of the piece is a well known bluetooth developer. When a group like that suddenly starts saying 'we can work together' it is pretty much an admission that the other side has established a dominant market position that can't be reversed.

    If there is genuinely a need for a low power Wireless lan then I would much prefer that someone do 'low power 802.11b' rather than attempt to reinvent the wheel.

    • The big idea of bluetooth appears to be to make my cell phone talk to my laptop.

      That's not what the piece says, and it's not what I've heard. It's to make everything talk to everything, in a standard, wireless way. More like a replacement for USB than a replacement for Ethrnet.

      The developers appear to be part of some OSI holdout 'IP will go away' group

      The author explains why they don't use "IP"-- the devices just aren't powerful enough to implement it. He also mentions that the spec includes PPP.

      The author of the piece is a well known bluetooth developer.

      Who would know more about the purpose and functionality of bluetooth?

      When a group like that suddenly starts saying 'we can work together' it is pretty much an admission that the other side has established a dominant market position that can't be reversed

      If the 802.11b is dominant and sufficient, why would IEEE be working to incorporate Bluetooth into its own standard? I don't know why you care so much about this. If Bluetooth's not useful to you, you don't have to use it.

      • This thing about devices ''not being powerful enough'' for IP is completely bogus. You can get very good TCP/IP stacks that operate on an 8051.
      • That's not what the piece says, and it's not wh.at I've heard.

        Hmm, you don't seem to have read the bluetooth web site then. That was their 'big idea' 12 months ago.

        If the 802.11b is dominant and sufficient, why would IEEE be working to incorporate Bluetooth into its own standard?

        Ever been member of a standards group?

        All your statement tells me is that someone in the IEEE has a bluetooth axe of some sort to grind.

        • Hmm, you don't seem to have read the bluetooth web site then. That was their 'big idea' 12 months ago.

          Some standards seem to do this. One day they say they'll do X. When people investigate it, and find the standard is a bad way of doing X, then the originators say it's the way to do Y. When people investigate and find it's also a bad way to do Y, then they're told it's the best way to do Z. Repeat until the standard fades away.

    • In the home there are very few devices that I would want to have on a wireless network that do not have an AC cord attached - so power consumption is not a big issue.
      Well, then they're not very wireless, are they? Too bad networking-over-power-cables never panned out.
    • The big idea of bluetooth appears to be to make my cell phone talk to my laptop.

      That's one of of many purposes. I for one would be most unhappy to part with my Bluetooth wireless headset. That headset is one of the best investments I've made this year - apart from the bluetooth-enabled phone that I use it with :-)

      Bear in mind that Bluetooth and 802.11b have different purposes. Making a wireless LAN with Bluetooth is just a pointless as making an 802.11b enabled phone.

      • Cool! Can you post a link? My phone is almost six months old now... almost time for a new one. :-)
        • Can you post a link ?

          Sort of...

          It's an Ericsson HBH-10 Bluetooth headset coupled with an Ericsson R520m triband phone. But the new Sony-Ericsson web-site has been designed by some flash-nut so after a certain point the URL stays the same.

          Furthermore, I couldn't find the phone on the US version of the website. That doesn't mean that it is not on the market in the US judging from the Ericsson newsgroup [alt.cellular.ericsson], just that Ericsson won't tell you about it.

          So here is the link to the UK website [sonyericssonmobile.com]. The headset is found under accessories.

          BTW, nice website you've got.

      • Making a wireless LAN with Bluetooth is just a pointless as making an 802.11b enabled phone.

        Yes, except that an 802.11b enabled phone would effectively be a VoIP cell phone. If the freenets [freenetworks.org] have their way, you could set up your own VoIP gateway back at home on your broadband connection and have your very own cellular phone, sans air time charges. Naturally, it would be a little flaky and a little limited compared to the commercial cell networks, but you did hear me when I said sans air time charages, right? The same goes for contracts.

        And besides, all those issues will be solved [sourceforge.net] eventually [sourceforge.net].
    • > I would get a GPRS card for the laptop. Calling plans will soon adapt to that use, they have in Europe

      So when you want to look up a phone number from your laptop, you will need to call your laptop from your phone? And then more phone numbers for your PDA, digital camera, and mp3 player too? How about hands-free headphone? Can we put a GPRS card in the headphone?

      > In the home there are very few devices that I
      would want to have on a wireless network that
      do not have an AC cord attached - so power
      consumption is not a big issue

      Devices that I'd like to have wireless connection with my computer: mouse, keyboard, PDA, digital camera, mp3 player, gamepad, mic, headphone, remote control.
      • So when you want to look up a phone number from your laptop, you will need to call your laptop from your phone? And then more phone numbers for your PDA, digital camera, and mp3 player too?

        Actully with SS7 layer switching it is pretty easy to do call forwarding. But you only need a phone number to receive voice calls, not to make 'em.

        I would rather mess with that than trying to get my cell phone to make data calls for my laptop. For a start I don't want to be messing with two sets of batteries. On most of the occasions I need to do data communications I have my cell turned off because I am in a meeting. That is if I bother to carry it which I don't most of the time. But having to worry about two wireless links to fall off?

        If you want wireless keyboard, Logitech sell one already. I have one in my office, it is OK but I am not too keen on its security. I can see a small advantage to having a standard there, but I would much rather there was something less meglomanical in its scope and had real security not more amateur hour stuff like WEP.

    • Dealing only with technologies available today, I would say putting GRPS in the laptop is reinventing the wheel. The laptop will have bluetooth/802.11. The form factor of the cell phone will keep it viable for at least a year or two, and modern GSM cell phones all have GPRS. Using bluetooth between the laptop and the cell phone for data access makes good use of existing hardware.

      I could see doing away with the cellphone if something just as portable has access to a GSM/GPRS network, such as a PDA. Then bluetooth headsets become pretty cool. Beware devices such as the trio which have no device-to-device communications - everything goes through the GSM network where it will cost money. I think that palms talking to palms or other devices without the need for infrastructure such as cell towers, will become increasingly important. My own interest is multiplayer games.
      • Dealing only with technologies available today, I would say putting GRPS in the laptop is reinventing the wheel. The laptop will have bluetooth/802.11.

        Err hello, what laptop is there that offers Bluetooth today?

        GPRS has always been intended to support PCMCIA format plug in cards.

        What you call 'reinventing the wheel' I call 'introducing a completely unnecessary technology into the process'.

  • Could someone explain the difference between a Local Area Network and a Personal Area Network? What constitutes the difference, or is it just a marketing term? I have (what I believe to be) a Local Area Network in my room. It consists of my computers, which are my personal property. Should I be calling it a Personal Area Network instead?

    Gawyn
    • Ah, people these days don't have a clue about mithology. LAN devices use network adapters. PAN devices use a wind instrument to communicate with each other, and they also have horns and goat legs.

    • Re:LAN / PAN? (Score:3, Informative)

      by Hast ( 24833 )
      No a LAN is not the same thing as a PAN.

      When your computers talk to each other they use a LAN. PAN are for keyboards, mice, printers and that sort of things.

      The idea is that you should be able to take your palmtop computer and put it close to a mobile phone, keyboard and printer. Select "connect" (With appropriate security.). Then use the keyboard to download somehting and print it. You could do this today with USB, the idea is to have it act seamlessly with wireless tech.
      Compared to LAN's you could say that a LAN is for moving a lot of data (1Mbps +) and a PAN is for doing "magical" things with your equipment.
    • It's pretty simple. In order to get investors, you have to make it seem like there is a market for your new gizmo. In order to make it appear that there is a market, you need to give the market a name, say XYZ. Then you get all of the techie magazines to start talking about XYZ, and how great it is going to be. Once you have "defined" the market in this way, people can start investing in XYZ so that gizmo makers can start making their gizmos to satisfy the pent up demand which is clearly demonstrated by all the magazine buzz about XYZ. Then a bunch of "XYZ" companies IPO, and several people "call in rich". The rest, of course, watch their investments dwindle to nothingless as the overheated gas escapes....
    • I would define a PAN as anything that is within arms reach to a few steps away, usually sans wires. Think printers, mice, keyboards.

      A LAN OTOH, is wired, and is for devices in the same or other rooms, connecting devices such as computers, network printers, and possibly access points to external networks.

      It's a matter of scale, in both data transfer and
      the distance.
      PAN = ~6ft. radius
      LAN = House, Office, Small campus

  • Practial answer -- they can and do work together (Score:3, Informative)

    by rochlin ( 248444 ) on Sunday October 28, 2001 @03:37PM (#2490157) Homepage
    In the real world, people have successfully combined bluetooth devices and 802.11b networks on a large scale.

    Look at UPS $100MM Project. [cnn.com] (CNN.com story)

    Symbol Technologies helped them do it and have been working with the IEEE (pdf file) to make sure 802.11b and Bluetooth don't destroy each other.

    But the important point here is that co-existence isn't automatic. You've gotta know what you are doing!

  • Two entirely different purposes (Score:3, Informative)

    by BigJim.fr ( 40893 ) <jim@liotier.org> on Sunday October 28, 2001 @03:38PM (#2490161) Homepage
    Bluetooth = cable substitute. With cables, connecting n devices together means n^2 different cables. With Bluetooth, that's zero cables. It is meant to connect your camera, your cellphone and your PDA together with your PC.
    802.11 = local area radio network. Same as Ethernet, but wireless.
    Journalists like to pit things against each other to generate drama. It makes their analysis less bland. Too bad that it completely screws up their vision of the market . Bluetooth and 802.11 are filling two entirely different ecological niches. True, there is a little bit of overlap, but they are more complementary than anything.

    • Re:Two entirely different purposes (Score:1, Informative)

      by Anonymous Coward
      Blue tooth is too slow to be a cable substitute except for the lowest-end applications. Going forward it is a dinosaur [eetimes.com].

      Here is the real picture:

      900 MHz - portable phones (land line)

      2.4 GHz - wireless ethernet (802.11b), wirefree (and more reliable) substitute for usb cable applications

      5.4 GHz - hi-speed wireless ethernet (802.11a), wirefree substitute for firewire (and digital video) applications

      low power versions of 802.11b are currently being worked on and will supercede anything developed by bluetooth - and if you really want to talk locally at bluetooth speeds use IR - direct lines of sight are easy to arrange in a PAN (personal area network) and IrDA operates at 4x blue tooth speeds and costs next to nothing
      • Blue tooth is too slow to be a cable substitute except for the lowest-end applications.

        Exactly - and that is indeed its purpose. Bluetooth was never intended to be a competitor with 802.11a/b. Would you use 802.11b for a wireless headset for a mobile phone? Of course you wouldn't. Bluetooth is perfect for that.

    • Yes, but n is limited to 8... I'm not an expert in bluetooth. But what I know of it, you're limited to 8 nodes in your piconet. If you need more, you can swap them in, but that can take up to a second and a half. I'd much rather have the wires running statically, and not have to wait for a swap in.

      --
    • With cables, connecting n devices together means n^2 different cables.

      Actually, it can be done with approximately n cables, using a hub or ring architecture. All n computers on the internet are connected with MUCH less than n^2 cables, for example. That is why ethernet is so popular.
    • The only reason why your camera, your PDA, your printer, your mouse, your keyboard, and all that are not on Ethernet is because Ethernet is too expensive. If you could make Ethernet as cheap as USB, serial, or parallel, many devices would have used it long ago (there are also configuration and real-time issues, but those would have been worked out).

      If Bluetooth manages to live up to its claims of low power consumption and low price compared to 802.11b, then it offers a genuine advantage. If not, it's just another superfluous standard.

  • As free as the air (Score:3, Interesting)

    by Erris ( 531066 ) on Sunday October 28, 2001 @03:41PM (#2490166) Homepage Journal
    Communication over such distances requires relatively high-power transmissions, and, because of that, a license for a specific frequency band. Typically, carriers pay a fee for a license to transmit at certain power levels in a particular frequency spectrum.

    Or so some would have it. Is anyone else getting sick of fees to do anything marginally useful? The ariwaves are public property and should be used for the public good, not simply to raise revenue for private companies. Whatever "standards" are adopted, let's see to it that the air itself is free.

    • Wrong (Score:3, Insightful)

      by Moooo Cow ( 79655 )
      You've got it backwards - this does not raise revenue for private companies, it raises revenue for governments that sell it.

      In fact, these rules prevent private companies from strong-arming their way into the market just because they have lots of money. Suppose that IBM coveted the same radio spectrum as your favorite community-hippie radio KHIP (yes, I'm guessing this will apply to you, Erris... don't ask me how I know). With the rules in place now, they can't simply start using it in a way that would interfere with your ability to enjoy the Arlo Guthrie marathon currently playing on KHIP.

      Wireless bandwidth is a limited resource, and there needs to be a minimal set of rules to regulate its disposition (akin to the Land Title Registry for real estate for example). Without these rules, no one gets any productive use out of it, and you will find there is no "public good" for you to defend.
      • You've got it backwards - this does not raise revenue for private companies, it raises revenue for governments that sell it.

        The government is only a tool, though I'm sure they enjoy recieving the $500,000 per year a comercial radio liscense costs. Why should I bite into the hideous comercial music troll? Because it's a good example of high fees being used to artificially limit the use of a public resource. How else are they going to raise that kind of money and pay their staffs and buy loudspeakers, advert vans and all the rest of that ugly noise? How else can five publishing companies dominate the music industry? The rules have been bent to benifit a few companies at the public expense.

        There really is plenty of bandwith to go around. Check out the 72 empty TV channels on an old tuner dial. Why is it that only a few broadcasters owned by GE, Westinghouse and Disney use it? Do you really think a free market dully regulated for the public interest would have all that redundant commercial noise, but mostly empty spectrum? How many reruns do you need to see before you go buy that soap? Great use, a productive use you say. Barf, I say.

        The price of broadcasting and computing equipment has come down to the point that a member supported digital network is possible. What barriers really exist? Most US suburbanites can afford antena towers, directional broadcasting equipment and multiple computers. We've seen plenty of implimentations right here on Slashdot. Trolls, who wish to fill up such broadcasts with adverts could be taken down under a proper leagal framework and pull based networking. People can co-operate to help themselves, without paying absorbadent fees to useless and annoying third parties. The physical devices are cheap and getting cheaper.

        Networking bliss seems right arount the corner, but then I hear from folks like you. If such a network does not emerge, it will only be because tellephony, publication and entertainment interests are able to control the airwaves for their own benefit. They do that through government regulation and soothing talk that comforts and leads silly cows to the milking stalls.

  • Bluetooth and 802.11 (Score:4, Interesting)

    by SrlKlr ( 219192 ) on Sunday October 28, 2001 @04:28PM (#2490280) Homepage
    Bluetooth not only lowers throughput in a 802.11b network, but if too many pico net form, it can actaully bring it down. Bluetooth started as a wire replacement, but it seems to have many more possibilities today. The best solution for Bluetooth and 802.11 is move 802.11b to 802.11a. 802.11b uses 2.4 GHz to communicate (thats also what microwaves use). Because of that, 2.4 is not regulated throughout the world. 802.11a can reach speeds up to 54 Mbps, so it will be replacing 802.11b, which can only do 11 Mbps. The good thing about 802.11a is that it tranfers at 5 GHz, so there is no interference with Bluetooth. This seems to be the best fix between the two protocols, if only 802.11a was a bit cheaper...

  • Interference (Score:4, Informative)

    by funky womble ( 518255 ) on Sunday October 28, 2001 @04:45PM (#2490312)
    There are interference problems between the original specs of bluetooth and 802.11b. There are working groups at IEEE trying to sort it out (search their website or search google for "802.11b bluetooth interference" and dig away).

    Fortunately some modifications have been suggested to Bluetooth which should significantly reduce the problems. Let's just hope that these are incorporated into any mass-market bluetooth devices or it doesn't bode well for wireless internet access via 802.11b in some places, for example, coffee shops, where you are also likely to see a lot of mobile phones...

    Frequency-hopping systems generally use frequencies from within a wider band but keep jumping between them, so they don't interfere with any one other user for a long period of time. Trouble is, this doesn't tie in very well with ethernet/TCP protocols where performance is seriously impacted by packet loss. (Sure, the packets are resent, but TCP treats packet loss as congestion and slows down).

  • I once lost my logitec cordless destop mouse...
  • wo/man's ability to come up with endless ways to give her/himself cancer. Good to see that people won't be tricked into using just one. Now they'll have two that don't compete.

  • Coexstance (Score:2, Informative)

    by Sase ( 311326 )
    I could see how they would coexist.. but I think you all might find this interesting.

    A few months ago I attended something in NYC called "PC-XPO" I'm sure a bunch of you have heard of it. It's a pretty large event. Many, many big companies come and show off their stuff. IE Compaq, Intel, AMD, etc.

    Every station at this place was connected in some shape or form.

    I would have to say that there were apprx. 1000-2000 computer systems there at one time. There were a lot of laptops operating wirelessly (802.11b). Also a significant amount of desktops were also working wirelessly.

    Interestingly enough, several vendors were showing off their "new" bluetooth technology (like Toshiba, printer companies, etc.)

    Point is, I must have brain cancer after spending so many hours there (no, not really). Who knows how many were transmitting across that frequency band. *BUT* they were all working in coexistance, and at very high speeds. There were some pretty smart people who designed the show, so they must have thought of the problems with the two technologies.

    Interesting.
  • Bluetooth is a short range, low bandwidth replacement for USB, earphone cables, parallel cables, serial cables etc etc. 802.11b is a replacement for Ethernet.

    What is it about this concept that is difficult?

  • At my university there is a project of trying to combine both technologies. They think this can be done by the "softeware radio princple". This means that you use the same hardware for the compatible electrical building blocks (Oscillators, mixer, amplifiers, detecters)

    With technique one can switch a radio circuit from BLuetooth to 802.11 and back without changing hardware. Looks nifty to me...

    Visser.
  • Interesting points and summarizes my understanding of the situation. However, what is to stop the development of low range, low power consumption, Voice Over IP based solutions for 802.11 that compete directly with BlueTooth? Bandwidth is not an issue, the IP overhead can be absorbed in the 11MB/s transmission rate. The 802.11 solution would be "more compatible" with other technologies (e.g. much easier to connect an 802.11 cell-phone to your network than a bluetooth cell phone).

Slashdot Top Deals

"Here's something to think about: How come you never see a headline like `Psychic Wins Lottery.'" -- Comedian Jay Leno

Close