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.""
Re:this is not new information
by
hattig
·
· 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).
Bluetooth & 802.11b are capable of Co-Existenc
by
hidden72
·
· 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.
Re:this is not new information
by
Fnkmaster
·
· 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).
Practial answer -- they can and do work together
by
rochlin
·
· 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
·
· 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
Anonymous Coward
·
· Score: 1, Informative
Blue tooth is too slow to be a cable substitute except for the lowest-end applications. Going forward it is a dinosaur.
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
Bluetooth is noncompetitive (Re:WPAN?)
by
isdnip
·
· 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.
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.
Interference
by
funky+womble
·
· 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).
Bluetooth does AT LEAST one thingI want to do
by
ebbe11
·
· 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.
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
·
· 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.
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.
Slashdot Mirror
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
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 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.
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_
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.
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.
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).
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
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.