Posted by
Hemos
on 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 is not new information
by
Fnkmaster
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· Score: 5, Insightful
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).
Re:this is not new information
by
gr
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· Score: 2, Insightful
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.:^>
-- Do you have a/. uid shorter than five digits? No? Then piss off.
Re:this is not new information
by
hattig
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· Score: 5, Informative
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).
Re:this is not new information
by
Fnkmaster
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· Score: 2
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?
Re:this is not new information
by
Fnkmaster
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· Score: 2
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.
Re:this is not new information
by
Fnkmaster
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· Score: 3, Informative
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. 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).
Re:this is not new information
by
geomcbay
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· Score: 2
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.
Re:this is not new information
by
geomcbay
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· Score: 2
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.
Re:this is not new information
by
BeBoxer
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· Score: 2
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
by
BeBoxer
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· Score: 2
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.
Re:this is not new information
by
BeBoxer
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· Score: 2
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.
Excellent Resources
by
webword
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· Score: 5, Informative
These are my favorite resources on this subject...
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?
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.
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.
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.
--
They that quote Benjamin Franklin on liberty and safety deserve neither.
Bluetooth & 802.11b are capable of Co-Existenc
by
hidden72
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· Score: 2, Informative
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.
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...
On a related note, 802.11a uses 5.4GHz
by
Black+Acid
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· Score: 3, Insightful
The new 802.11a uses the 5.4GHz 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
by
Zeinfeld
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· Score: 5, Interesting
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.
--
Looking for an Information Security student project suggestion?
Try http://dotcrimeManifesto.com/
Re:But Bluetooth does nothing I want to do
by
Webmonger
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· Score: 2
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.
Re:But Bluetooth does nothing I want to do
by
warmcat
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· Score: 2
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.
Re:But Bluetooth does nothing I want to do
by
Ian+Bicking
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· Score: 2
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.
Re:But Bluetooth does nothing I want to do
by
Zeinfeld
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· Score: 2
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.
--
Looking for an Information Security student project suggestion?
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Re:But Bluetooth does nothing I want to do
by
Zeinfeld
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· Score: 2
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.
--
Looking for an Information Security student project suggestion?
Try http://dotcrimeManifesto.com/
Re:But Bluetooth does nothing I want to do
by
Zeinfeld
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· Score: 2
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'.
--
Looking for an Information Security student project suggestion?
Try http://dotcrimeManifesto.com/
Re:But Bluetooth does nothing I want to do
by
gorilla
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· Score: 2
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.
Practial answer -- they can and do work together
by
rochlin
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· Score: 3, Informative
In the real world, people have successfully combined bluetooth devices and 802.11b networks on a large scale.
Two entirely different purposes
by
BigJim.fr
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· Score: 3, Informative
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
by
ChadN
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· Score: 2
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.
--
"It's overkill, of course. But you can never have too much overkill." - Anonymous Slashdot Coward
As free as the air
by
Erris
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· Score: 3, Interesting
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.
-- DMCA, Hollings, Palladium. What might have sounded like paranoia is now common sense.
Bluetooth is noncompetitive (Re:WPAN?)
by
isdnip
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· Score: 5, Informative
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.
Re:Bluetooth is noncompetitive (Re:WPAN?)
by
SurfsUp
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· Score: 2
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.
-- Life's a bitch but somebody's gotta do it.
Re:Bluetooth is noncompetitive (Re:WPAN?)
by
DJerman
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· Score: 2
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:-).
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.
Bluetooth and 802.11
by
SrlKlr
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· Score: 4, Interesting
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
by
funky+womble
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· Score: 4, Informative
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).
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.
-- Slashdot is entertaining like pro wrestling is entertaining
Bluetooth does AT LEAST one thingI want to do
by
ebbe11
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· Score: 3, Informative
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.
--
My opinion? See above.
Re:Bluetooth does AT LEAST one thingI want to do
by
Nater
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· Score: 3, Interesting
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 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.
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.
-- ------------
Sase
"It's the opposite of that."
Not true, you only need the HCI-layer
by
mikael
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· Score: 2, Informative
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.
"...removing Microsoft's IPX/SPX compatible protocol and Novell's IPX 32-bit protocol from the dialup adapter bindings resolved the error."
Re:Bluetooth & 802.11b are capable of Co-Exist
by
hidden72
·
· Score: 2, Informative
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.
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.
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).
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?
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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
These are my favorite resources on this subject...
Bluetooth Resource Center
A Businessman's Comparison of Bluetooth and Wi-Fi (802.11b)
Empirical Study for IEEE 802.11 Aand Bluetooth Interoperability (PDF)
Wi-Fi will not make Bluetooth obsolete
How to Download YouTube Videos
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?
Guvegrra?
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.
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.
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...
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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.
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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 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!
A beginners' guide to Portland, OR?
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.
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.
DMCA, Hollings, Palladium. What might have sounded like paranoia is now common sense.
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.
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.
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...
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...
Fighting for peace is like fucking for virginity
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.
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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.
My opinion? See above.
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.
------------
Sase
"It's the opposite of that."
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.
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
"...removing Microsoft's IPX/SPX compatible protocol and Novell's IPX 32-bit protocol from the dialup adapter bindings resolved the error."
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.
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.
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).
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?
Government of the people, by corporate executives, for corporate profits.