Airgo Quadruples Wi-Fi Limit

QED writes "Airgo Networks, a privately held maker of wireless networking components, said on Wednesday it has developed chips that will increase the Wi-Fi speed limit by a factor of four. The Palo Alto, California-based company, which designs its chipsets around Multiple Input and Multiple Output (MIMO), a wireless technique that uses different radio channels to improve both speed and transmission quality, said it has achieved data rates up to 240 megabits per second (Mbps)... "

Comments

Multiple paths, not multiple frequencies?

[RradRegor]

I'm not certain, but I think the word channel may be misleading here. I think that MIMO is actually using the same bandwidth, just combining multiple RF paths to enhance the signal to noise ratio. Another MIMO link is here.

This doesn't interfere

[G4from128k]

That a great way to be a good neighbor. Piss all over all the channels available so no one else can do anything.

I was about to post with the same sentiment until I read more on the tech.

MIMO is not your typical blast-it-on-multiple channels approach. This article discusses the technology. Instead of using up a bunch of channels, MIMO systems send multiple signals on one channel and use multiple antennas and advanced algorithms on both ends to sort out which signal came from or went which direction.

Still not as fast as wired.

[Guspaz]

4x the speed is still not that great.

Current 802.11g devices have a theoretical throughput of 54mbit, and a real-world throughput of actual data of 10 to 20mbit. So it follows that Airgo's new cards will permit 40 to 80 megabits.

Now, wired 100mbit networks can reach 80mbit real-world speeds (Actual after-overhead bandwidth), so at first glance it looks like we're there. Except we're not.

The important things to keep in mind is that wireless networks behave like hubs, not switches, and on top of that all data must go through the access point. So if you have two computers close to an AP, you take up 40mbit for computer -> AP, and the other 40mbit for AP -> computer.

In other words, they claim 240mbit, but the fastest real-world transfer between two wireless devices is probably about 40mbit, IF those computers are very close to the access point. If the computers are a bit further away, you will get 20mbit. 4 computers doing 2 transfers and each transfer goes at 10mbit.

So you see? 4 computers 50 feet away and you're already down from 240mbit to 10mbit. This is very far away from wired performance.

Re:Question about Ethernet vs WiFi speed increases

[RingDev]

To put this in software terms, They are multithreading the connection.

-Rick

Re:It's called 802.11n

[aardwolf64]

Yep... and I've had one for a couple of months. Although I'm using it with 802.11b and 802.11g devices, I've noticed a big performance boost. The major advantages:

• The ability to go really fast
• No mixed mode (i.e. an 802.11b device on the network doesn't slow down 802.11g
• Greater range with existing 802.11b and 802.11g devices

The story behind this announcement

[RebornData]

Airgo is a participant in one of two consortiums of companies promoting competing technologies to use in the 802.11n standard. Here's an article that covers the situation:

http://www.reed-electronics.com/electronicnews/art icle/CA445702

Airgo is obviously trying to gain leverage with their technology by getting it out on the market early. I don't think this is a good thing in the long run, since we all have benefitted by the degree of standardization in 802.11b/g and Airgo seems to be trying to get their own proprietary technology out there in front of the legitimate standards process.

-R

You're talking about bonding, not MIMO

[tessaiga]

You're thinking of just taking different frequency channels and bonding them together. That basically just uses more frequency to transmit more data rate, while the number of bits per second per hertz (the spectral efficiency) remains the same.

In the MIMO system they're discussing here, you use the same frequency bandwidth but deploy multiple antennas, which gives you spatial diversity. Wireless communications are basically limited by the probability that your channel goes screwy and experiences what's called a fading event, where your signal suddenly drops because of interference. This means you have to be more conservative in the data rate you transmit at.

What they're trying to do is transmit, receive, and resolve multiple signals in the same frequency band by using multiple antennas, and resolving them in a clever way to try to create independent data channels. Since each antenna is physically at a separate location, the signal paths (and hence the fading characteristics) from the transmitter to the receiver will be more independent. Then the odds that all channels experience fading simultaneously drops significantly, improving the overall robustness of your communication channel to fading. That means you can be less conservative and achieve higher bit rates through your channel.

In short, same frequency usage, but they're getting spatial diversity by using more antennas and giving themselves a more robust channel.