Has 2.4 GHz Reached Maximum Capacity? 250
An anonymous reader writes "There's been a lot of talk lately about the concept of Personal Area Networks. At CES Intel and Connectify both released software that turns Windows laptops into Access Points for file transfers, wirelessly syncing pictures from cameras, and Internet sharing. This is good, maybe great, if you're a road warrior, but what about the rest of us holed up in apartment buildings and small neighborhoods? We already have to deal with the wireless chatter of the 50 or so other Linksys routers in the vicinity. What will happen when every laptop also acts as a software router? To add fuel to the fire, Intel and Netgear also announced the Push2TV device that allows you to stream your display, including Netflix videos straight to your television. Isn't this going to kill lower powered 2.4 GHz devices, like Bluetooth mice and headsets? When does the 2.4 GHz band collapse completely? Why can't we push all this short range, high bandwidth stuff onto 5 GHz?"
The problem (Score:1, Insightful)
The problem is each technology is developed without consideration for large numbers of concurrent devices using the same spectrum. Between encryption, poor handshaking, EMI from non-compliant devices, and attempts by manufacturers to overpower their devices with turbo this or ultra that, the end result is that in high device density areas, the technology becomes nearly useless. This is actually the FCC's fault -- they haven't allocated a large chunk of bandwidth exclusively for consumer-based hardware that provided packet-based network services that requires licensing and certification to use. The 2.4GHz band is like CB Radio -- sure, it's illegal to use a 500 watt transmitter on your mobile rig, but since everybody else and their dog uses it, you should too.
Manufacturers need to come up with protocols that allow the use of strong encryption AND still allow traffic management and QoS. In other words, stop setting up a bazillion different networks: There is one network per channel. Encryption is enabled by default, and that key determines whether which packets can be decrypted. That way, all the header information and link-level stuff that's essential for management is still available, but a reasonable level of privacy is still possible.
Re:your router is yelling and you dont even know i (Score:4, Insightful)
God help you if you want to use your microwave. You'll kill the connection to every device in your house.
But I am on 5 GHz (Score:2, Insightful)
Since I _don't_ deal with a lot of Windows PCs, I _am_ running everything on 5.0 GHz. Well, OK, there's a "guest WiFi" at 2.4 GHz for friends, but I don't care if that's broken.
Most PCs I've seen with 802.11n only have the 2.4GHz support, and same with a lot of add-on cards and access points. The dual-band stuff is starting to be a little easier to get, though still a bit of a price-premium. Of course, since my machines are either Macs on Wi-Fi or Linux on gigabit copper, I'm already used to a price premium.
However, there's a good side effect of this: a certain eggy on-line store had a whole bunch of refurbished Netgear 5.0 GHz _only_ access points/bridges on for less than $40. So the couple of devices I have that don't do WAP and/or don't do 5.0 GHz are now using those things. Similarly, I set up a friend's office to use one so his Macs aren't drowned out by all the 2.4 GHz chatter in the area. (Downtown, right beside a condo and hotel, across the road from an office building... and almost everyone on channel 1, too.)
Heck, $40 is less than the price of a USB 802.11n adapter. So I bought a couple extra just in case.
So, if everyone else would just _stay off_ 5.0 GHz, I'll be very happy.
Re:your router is yelling and you dont even know i (Score:5, Insightful)
Yup, none of the access points are actually smart enough to switch channels and optimize frequency/power usage. So you end-up with the problem I encountered this December, when a neighbor across the way got a wireless router, and suddenly my internet stopped working. You couldn't even *see* my access point anymore, it was just overpowered.
My access point configuration was set to "Auto," but this just meant it kept trying to use channel 1 like an idiot. So I forced it to use channel 6, and the problem was solved.
But this isn't how things should be. The devices and the protocol should be smart enough to optimize spectrum, both by analyzing the noise at various frequencies and choosing the band with the least automatically, and by playing nice with other devices and dialing-down the power to that needed by the connected device furthest from the access point.
Too bad the above is just a pipe dream. I can't imagine how bad it is living in dense residential/apartments, where these users still don't know how to configure things, but there are 2 dozen within range instead of 5.
Re:your router is yelling and you dont even know i (Score:3, Insightful)
Yup, none of the access points are actually smart enough to switch channels and optimize frequency/power usage. So you end-up with the problem I encountered this December, when a neighbor across the way got a wireless router, and suddenly my internet stopped working. You couldn't even *see* my access point anymore, it was just overpowered.
My access point configuration was set to "Auto," but this just meant it kept trying to use channel 1 like an idiot. So I forced it to use channel 6, and the problem was solved.
But this isn't how things should be. The devices and the protocol should be smart enough to optimize spectrum, both by analyzing the noise at various frequencies and choosing the band with the least automatically, and by playing nice with other devices and dialing-down the power to that needed by the connected device furthest from the access point.
Too bad the above is just a pipe dream. I can't imagine how bad it is living in dense residential/apartments, where these users still don't know how to configure things, but there are 2 dozen within range instead of 5.
That all works in my favor. Nearly everyone in my complex has their router set to channel 6 or something. I set mine to channel 1 and I've got all the reception I could ask for!
-Taylor
Re:Channel 14 (Score:2, Insightful)
Antennas and Rx/Tx architectures (Score:5, Insightful)
The problem is dumb receivers, not lack of spectrum.
Channel capacity is determined by the MIMO form [wikipedia.org] of Shannon's Theorem [wikipedia.org]. Add more antennas and smarter processing in the receivers, and the capacity in a channel with lots of multipath (eg. in an apartment) increases approximately linearly.
The problem is that most hardware is a decade (or more) behind state of the art, and that people aren't prepared to pay for a more complex, and costly receiver.
Re:Apartment Wifi (Score:3, Insightful)
Anyone can get your WEP key with just a handful of minutes and a tiny bit of know-how. If someone knows enought to try changing its settings to make it better suit their needs, you can be sure they can crack your WEP key. Cracking WEP networks is particularly easy, and useful if you live next to the network in question.
Seriously people, stop using WEP unless you actually understand the consequences and can make an informed decision to ignore them.
Also, ethernet and wifi are significantly different beasts (though DVD quality probably shouldn't be an issue.)
There's always a garbage band... (Score:3, Insightful)
Before that, it was the 900 MHz band -- until it filled up with cordless crap.
As others have posted, 5 GHz is still pretty clean, so use it while you can. In our residential area, 2.4 GHz is full (even 14 is in use), but there's little activity on 5 GHz, so that's where our macbooks connect.
Same at work -- dual mode phones, bluetooth, microwave ovens, old laptops and more all on 2.4, with the newer equipment connecting on 5 GHz.
Re:The problem (Score:3, Insightful)
A laptop that sits on a desk 24/7 (like most of them do) isn't being used as a portable device and doesn't need wireless in the home. If you can plug in a power connector you can certainly plug in an ethernet cable too. Heck, a docking station even takes care of that for you.
Re:The problem (Score:4, Insightful)
Most people don't have ethernet in every room though. Since the router often has to be in a certain place (i.e. where the phone line comes in) wifi to the office/bedroom makes sense. In fact that is supposed to be one of the biggest benefits of wifi.