Xbox 360's Jamming Wireless Signals? 222
WirePosted writes "A report has emerged suggesting the Xbox 360's inbuilt wireless system for communication with wireless controllers and headsets is transmitting over a wide area of the 2.4Ghz spectrum, causing interference to WLAN's and other 2.4Ghz devices."
Microsoft and Radio? Help us all.... (Score:1, Informative)
I don't know what other IT guys thought when we found out the Xbox was using 2.4 Ghz for it's controllers, but I laughed out loud!
2.4 Ghz is one of the most badly managed spectrum for consumers. You have phone systems that take out access points, access points that take out phone systems, and no idea at all which of those systems will interact badly with another.
And you can't fix it either! Access points use a static channelization for their transmission, and controllers/phones use spread spectrum. Why is that bad??
It's bad because 2.4 Ghz is radio, carrying digital info, which due to the nature of the produced sign wave results in a signal distortion more commonly known as "bleed over". Without the ability to separate the signals by a large frequency, digital over analog bleeds all over the place. Additionally, spread spectrum ensures the signal will at some point transmit across the whole spectrum.
Add to that the fact that these antenna aren't tuned all that well....
Oh well 2.4 Ghz is a mess. No one likes to talk about it... and companies are still making equipment for 2.4 Ghz.
Caveat Emptor.
Didn't notice (Score:4, Informative)
Re:Microsoft and Radio? Help us all.... (Score:5, Informative)
It's bad because 2.4 Ghz is radio, carrying digital info, which due to the nature of the produced sign wave results in a signal distortion more commonly known as "bleed over". Without the ability to separate the signals by a large frequency, digital over analog bleeds all over the place.
The hell? There is nothing magic about digital data that means you can't bandwidth-limit the outgoing transmission. There are plenty of digital radio protocols that use a very well defined slice of bandwidth, without any more bleed over than traditional AM or FM radio analog broadcasts. Just because the signal represents digital data doesn't mean you have to use square waves or something.
I suppose we should all be thankful that radio engineers are better educated than the average Slashdot poster...
(Of course, it's entirely possible there's something broken about the XBOX radio. It's also entirely possible it's just a spread-spectrum transmitter doing exactly what it's supposed to do in a largely unregulated piece of spectrum.)
Re:Microsoft and Radio? Help us all.... (Score:5, Informative)
their internet connection is almost always the real choke point anyways.
This sounds a bit iffy (Score:5, Informative)
Re:How long has the XBOX 360 been out? (Score:3, Informative)
Re:Microsoft and Radio? Help us all.... (Score:2, Informative)
Rather, I'd hope "radio engineers" would take notes from the Slashdot posters. This way Slashdot posters, who have to trouble shoot wireless systems going down for no apparent reason, don't have to argue with "radio engineers" over a problem that is reproducible.
Also, you might want to ask why this "IT Director" (me) appears to know more about this problem than you do?
At any rate I've seen the sign wave off a couple of these wireless transmitters and it doesn't look clean to me.
But you know... I'm no "radio engineer". My license only reads "Technician".
Re:Read TFNOTBOED (Score:4, Informative)
Apostrophe's used for pluralizing!?! (Score:3, Informative)
Re:xbox wireless (Score:4, Informative)
Re:Microsoft and Radio? Help us all.... (Score:2, Informative)
Try being a Technology Director, with a radio license, and an EE from an excellent engineering school, plus 20 years experience in digital communications. I can personally tell you that it still doesn't make one an expert.
However, I can tell you you're way off base in your post. The whole point is that 2.4 GHz (not Ghz, BTW) is that it isn't managed! It's up to everyone to pretty much fend for themselves!
Good grief. No wonder it's a "mess" when people like you start talking about "sign" waves.
Re:How long has the XBOX 360 been out? (Score:2, Informative)
Re:Not just the x-box (Score:4, Informative)
The 360, on the other hand, doesn't have WiFi, and has wireless controllers that use a proprietary (I think) wireless system, on the same frequency spectrum as WiFi. There's every chance that it interferes.
Re:Microsoft and Radio? Help us all.... (Score:3, Informative)
Minor detail that you can't legally use that channel in the United States (or Canada?). Granted, the odds of getting caught are next to nothing, but I don't think this is a viable "fix" for anybody in the business world.....
Re:How long has the XBOX 360 been out? (Score:5, Informative)
Bluetooth doesn't "play nicely" with WiFi. Bluetooth (from 1.2 onwards) was designed to remove channels that are being used from it's hopping sequence. But until it detects that those channels are in use (which may take quite awhile if your wifi network doesn't have a lot of traffic) you are still going to have interference issues. WiFi will usually "win", in that if either of the devices is going to be affected by the interference it's much more likely to be the bluetooth one.
Re:Microsoft and Radio? Help us all.... (Score:3, Informative)
Re:Microsoft and Radio? Help us all.... (Score:4, Informative)
"Devices that use spread spectrum do not cause interference with each other"
There, fixed that for you.
Seriously, anybody that has ever tried to use an analog 2.4Ghz cordless phone near a busy wi-fi network knows that they do cause interference. Hell, I can even tell when my wi-fi has a burst of activity if I'm using my bluetooth headset.... and bluetooth is supposed to avoid channels that are in use.
Re:Microsoft and Radio? Help us all.... (Score:3, Informative)
I'm not saying that there isn't a problem. The article reads more like an advertisement in spots, but they do give a modest amount of technical info -- enough that I'm willing to believe the problem is real. It appears that the spread-spectrum controller is interfering with the WiFi signal. That's not overly surprising, but it has absolutely *nothing* to do with the fact that the data is digital. It has everything to do with the fact that these two devices are using each other's bandwidth and not handling the interference well, which is unsurprising given the relatively unregulated nature of the 2.4GHz band. The intereference could just as easily be caused by an analog source as a digital one.
Also, unless you're really experienced at it, you can't tell a clean, bandwidth-limited signal by looking at it in the time domain -- you need a spectrum analyzer. (If you're really experienced, you'll do ok, but the spectrum analyzer is still important.) Furthermore, "spread spectrum" is not the same thing as "not clean" -- not in the slightest. From the perspective of the other device, though, they may produce similar results (undesired interference).
The lesson here is not that the radio engineers are screwing up. (They might be, but there is no evidence presented to that effect.) Rather, it is that using multiple different transmission schemes in the same band without any coordination is likely to cause problems. And really, that's not exactly a surprising result. If you want someone to complain at, complain at the regulators for not providing more bandwidth with better negotiation protocols mandated.
Re:Microsoft and Radio? Help us all.... (Score:4, Informative)
You are right about 2.4 GHz devices interfering with each other. That's about it.
First: Wi-Fi devices may be assigned "static channels", but these are not minimally wide frequency bands as you imply. In fact, the channels are 30Mhz wide and contain spread spectrum signals. Channel 1 overlaps channels 2 through 5 enough to cause interference.
Second: Digital modulation techniques need not "bleed over" significantly past the bandwidth required to carry the information (i.e. potentially less than analog transmission of the same information). For example, psk31 is a digital mode with a bandwidth of about 31Hz.
Third: Modulated signals are necessarily not sine waves. Especially signals designed to look like noise (n.b. Wi-Fi is meant to look like noise across 30MHz of spectrum). You will see changes in frequency or phase (I'm not certain which). If individual cycles of the 2.4GHz waveform you saw looked rough then you made a mistake sampling the signal. Visible distortion of a single wave so far out of bad it would not affect any 2.4GHz devices.
BTW, my license says "Extra".
Re:Microsoft and Radio? Help us all.... (Score:3, Informative)
Try locking your access point to 802.11b-only mode and see what that does.
I've noticed the exact same problem you describe with a lot of 802.11g chipsets (Intel Pro/Wireless being the worst offender in my experience). Watching the devices they seem to switch speed rates constantly up and down for no obvious reason. Every single time a rate change happens the network communications stop for at least a few seconds. Eventually they just stop communicating altogether until the client is reset.
Once locked to 802.11b all of the devices remain connected at 11mbps. This should be a viable solution for you if you only need wi-fi to connect to the internet. 802.11b should provide at least 5.5mbps of usable bandwidth for TCP and upwards of 7mbps for UDP. If your internet connection is faster then that then I don't have a lot of sympathy for you, cuz mine isn't ;) If you need faster wireless (i.e: LAN file transfers) then you might need to look at finding different client cards or access points until you get a pair that communicates reliably.
The other thing I've noticed is that some of the Intel Chipsets try to implement a proprietary power saving scheme that causes issues with a lot of APs. You can usually disable this feature, though the specifics of how to do so would depend on which OS and drivers you are using.
Re:Microsoft and Radio? Help us all.... (Score:3, Informative)
Amateur Radio has secondary allocation status. (Score:3, Informative)
True, provided that you can prove that a device covered under part 15 was indeed causing actual harmful interference, and not just transmitting as designed. Until amateur radio receives primary allocation status of its section of 2.4GHz, I doubt that any ham would be very successful at kicking a part 15 device off their local airwaves.
Amateur radio has to comply with part 97, and the unlicensed devices have to comply with part 15, but the secondary allocation status for amateur radio (on 2.4GHz) puts the two almost on a level playing field as far as who has the "right" to be transmitting.