On-Chip Challenges
Now that you get the gist of how beamforming works, you’re probably wondering why the technology never went mainstream. After all, in comparison, trying to optimize signal strength with several antenna jutting from a conventional 802.11n access point is a joke. These multiple antennas are, in a way, glorified rabbit ears. Even if you spend the time to fiddle with them and get what seems to be the best throughput in a given spot with the antennas set in just such a way, what happens if you have to move the access point or the end client? What if you add a second or third client? It’s chaos. The fact is that proper signal optimization with current-gen products is futile.
Why hasn’t intelligent beamforming, which has the ability to sense optimal phasing and orient beams for multiple clients, been widely adopted? It’s a mystery—probably another one of those “we as an industry are still in the process of discussing various blah blah blah” things.
A skeptic might suggest that on-chip beamforming hasn’t taken off because it’s sounds better on paper than it is in real life. We know that, in theory, beamforming should save power. You only need to boost the signal in a certain direction and drop power for any signals that don’t assist that beam. The problem here is that when you’re dealing with omnidirectional antennas, there’s only so much control you can have over your beams.
For an intriguing illustration, check out Falstad’s Antenna Applet and be sure to choose Broadside Array from the top pull-down menu. You can increase antenna counts, play with the distances between them, and modify signal strengths. As you’ll see, with two omnidirectional antennas you never get away from having a lot of beams, and therefore energy expended in unneeded directions (these unwanted beams are often called backlobes). Naturally, if you have beams going off in stray directions, these can cause co-channel interference and impede the signal you actually do want.
It seems likely that next-gen 802.11n will incorporate implicit and explicit beamforming at some point, as there are very few technical or cost barriers. However, which approach will vendors integrate? And we haven’t even scratched the surface on options. For example, there are three sub-types of explicit beamforming. So if there’s one culprit behind the lack of beamforming adoption, concerns over interoperability is probably to blame. For those of who find yourselves thinking, “Come on! I don’t care about 100% interoperability. I just want crazy good wireless performance in my space,” keep reading.
- beamforming ,
- wifi ,
- ruckus
first post?!?!?!
No, REAL first, dipshit.
I don't think it's a problem that this is really only enterprise-class hardware. The very fact that there's an tenna sensitivity that can cripple the entire system shows that for Joe Apefist this is too much trouble for its own worth.
But, the tech shows amazing potential and given some tweaking time, I'm sure it will become more robust and more economical and will rapidly see adoption at home.
Personally I can't wait!
As a crude guide if you want 10dB gain over omnidirectional (10x the power in some direction) then you need to have 10 antenae to cover all directions. It works but with an obvious price in money and size, and a more subtle one in intereference for/from other transmitters unlucky enough to be in the chosen direction.
Personally I'd prefer multiple omni basestations and just focus on minimising distance. Inverse square law is your friend.
Personally I'd prefer multiple omni basestations and just focus on minimising distance. Inverse square law is your friend.
:-)
Yeh totally why punch through 4 walls when you can punch through 2. Plus you can site access points/ repeaters in free space away from mwave reflective objects.
Also note that much more important to enterprise wireless LANs is NOT the raw AP to single client thoughput that so many of these gearhead tests do. We are constantly faced with offering stable and usable wifi for dozens to hundreds of concurrent users in crowded areas (conference centers, auditoriums....) Like any shared medium, Wifi suffers from co-channel interference and overly RF loud clients.
One BIG advantage that you will see enterprise vendors work towards is NOT how much speed to any one client you can get, but how much Reduced interference beamforming will allow to neighboring wireless APs in the same ESS. The net result is that all users see benefit of solid and stable wireless connectivity.