Slashdot Mirror
High-Gain Patch Antennas Boost Wi-Fi Capacity In Crowded Lecture Halls
An anonymous reader writes "To boost its Wi-Fi capacity in packed lecture halls, Georgia Institute of Technology gave up trying to cram in more access points with conventional omni-directional antennas, and juggle power settings and channel plans. Instead, it turned to new high-gain directional antennas. They look almost exactly like the bottom half of a small pizza box, and focus the Wi-Fi signal from the ceiling-mounted access point in a precise cone-shaped pattern, covering part of the lecture hall floor. Instead of the flaky, laggy connections, about which professors had been complaining, users now consistently get up to 144Mbps (if they have 802.11n client radios). 'Overall, the system performed much better' with the new antennas, says William Lawrence, IT project manager principal with the university's academic and research technologies group. 'And there was a much more even distribution of clients across the room's access points.'"
why cram all the bodies into the hall?
When an on line video with DRV controls and notes are much better.
It is hardly newsworthy that a group of IT network techs 'fixed' their coverage and performance problems using directional antenna technology. Radio techs have been doing exactly that since they learnt about propagation. A newsworthy story would be that they have (finally) started incorporating at least basic RF theory in all IT networking related courses and subjects.
In Europe we limit the maximum radiated power (EIRP). This means you'd have to drop TX power and the directional antenna helps on RX only. Still might be worthwhile.
Although there is ample proof that WiFi don't have health issues, I still want to limit the EIRP. But to what level, I do not know. I think directional antennas currently have too strict a limit - you are not supposed to be standing next to a directional antenna anyway. OTOH people hardly understand what a 20dB antenna does (in TX).
This is a parroting of a marketing-derived press release. Move along. I think I'm going to move along. Thanks for the memories, Slashdot.
Plugging in that antenna invalidated the FCC certification of the AP
Georgia Tech are breaking the law!
News at 11
Wifi antennas concealed inside the elbow patches on the lecturers tweed jacket! What a great idea.
I think its funny how the summary says this like its some new fantastic technology. Directional gain antennae have been around almost since radio itself. There's nothing new about this, and if I had to guess, the ham radio club at Georgia Tech has been telling them to use directional antennae for a while now. Somebody with the authority to enact it managed to convince themselves that they though of it, did it, and now we're supposed to be impressed.
Nobodies Prefect
Tidbits for Techs Technology Blog
URGENT! URGENT! URGENT!
DISTRIBUTION: ALL STATIONS
MESSAGE READS:
IT guys fix their spotty wireless coverage by installing the proper antennas.
END URGENT MESSAGE
Wow, thank God for that. Good thing that we have slashdot to tell us that a university installed some standard equipment on their campus. Be sure to run an article when MIT replaces a couple of their switches next month.
-1 disagree is not a modifier for a reason. -1 troll, flaimbait, redundant, overrated are NOT acceptable substitutes.
Wi-Fi is an inappropriate distraction. Lecture is for listening. How else are you going to learn about the mathematics of wonton burrito meals?
I read TFA, and did a search on that "bottom of pizza box" antenna.
Found it @ http://www.terra-wave.com/shop/font-colororangenewfont-245-ghz-14-dbi-high-density-panel-antenna-with-nstyle-jack-connectors-p-2993.html
The only problem is the price.
The cost of the antenna alone is $591.25 a pop.
Perhaps Georgia Institute of Technology has a big endowment, that they can afford to install such devices all over their campuses.
For most private enterprises, on the other hand, it's simply not affordable.
Muchas Gracias, Señor Edward Snowden !
I was told by a ham radio operator back in the day that a radio setup is only ever as good as its antenna system (and that includes the coax and feedline) to me this simply sounds like they finally listened to the old man in the crew.
Cisco does this regularly for installations in sports arenas. Hell, the current crop of access points does active beamforming per client. If the marketing material is to be trusted...
Xirrus have been doing this for years - see http://en.wikipedia.org/wiki/Xirrus or http://www.xirrus.com/
They put 8 (or more) access points into a single unit, each with a directional antenna covering a segment of the room or venue. I looked at their product at a trade show or conference once (don't remember which) but it was way overkill for the spaces we had at the time which were separated with heavy reinforced concrete walls and floors, so needed an access point for each area.
that it's all about the antenna
They look like the TOP half of the pizza box!!!
It's always remarkable what people do with 802.11, but a lot of it strikes me as a mediocre standard being (over)extended with gimmicks.
Out of the box it works well enough for simple use, but more complex use cases (distance, density, broader coverage) seem to involve a lot of complexity to make up for the overall weakness of the standard (limited channel selection, radio power, etc).
Are there any changes on the horizon to generate new standards that would fix this? Such as designs tailored to high-density environments (hundreds or thousands of clients off a single radio), greater channel selections, better distance capabilities, etc?
I realize that not all of these may be something that works in a single product and that there are RF constraints that limit this, but at the end of the day the current 802.11 environment reminds me of DOS. Sure, with the right shims and magic you can run games (Quake, for the era) or a GUI OS on top of them, but there's something inherently hokey about it.
High gain directional antennas work better than low gain onni-directional antennas... Who knew?
Wasting 75% of your transmitted power by sending your signal out in a 360 degree radiation pattern instead of focusing all your power on a 90 degree 'wedge' is just stupid - I have to wonder who designed their wifi deployment, commission-based access point salesmen or results-oriented networking specialists?
Ken
This is exactly how high capacity AP's work. it has basically 4 (or more, I have seen some with 8) ap's that are connected to high gain antennas that segment off what they see. An advantage of high gain antennas is that they squish their signal and receive "window" into tighter lobes.
Honestly, if these people would take classes in RF design they would know this as the technology they are using has been around for decades, and the idea has been in use by companies covering large venues for at least a decade. The trick is the attenuation of the antennas' signal so you dont get a ton of reflections, you actually run that high gain antenna into an attenuator, plus you really crank down the power output for transmit.
Do not look at laser with remaining good eye.
When slashdot started some of the first stories here were about WiFi with directional antennas (eg. the famous pringles can long links). Long before I managed to get on the actual internet (instead of just a mere BBS) I knew people that were doing things with microwaves and directional antennas (microwave point to point link from a community radio studio to an FM transmitter). So is this story really just about somebody that actually decided to read up and get a clue about what were are doing instead of blindly hoping something would work? I think the real story is that the bar is set so low that an IT project manager working out what a first year physics or engineering student could tell them is rare enough to comment on. There's even free software that can map the signal strength now.
With quantity discounts. I actually own one of these.
http://www.l-com.com/wireless-antenna-24-51-58-ghz-20dbi-flat-panel-antenna-n-female-connector
Shop much?
What's the change in radiation exposure?
"If any question why we died, Tell them because our fathers lied."
The concepts of antenna radiation patterns and propogation has been fairly well understood for quite some time now.
... a dedicated controller to handle the new “high density group” of access points; and the controller automatically handled configuration tasks like setting access point power levels and selecting channels.
Centralized management of the access points seems to be the solution, which doesn't require directional antennas to work.
tomorrow who's gonna fuss
I've been out of college for just barely over a decade but this is making me feel very old.
Oh look! You've discovered http://en.wikipedia.org/wiki/Space-division_multiple_access
"Oooh. I hate it when a paradigm shifts without a clutch"
or old satellite TV antennas?
if this is supposed to be a new economy, how come they still want my old fashioned money?
This seems to help the APs focus their TX/RX, but what about the clients? When will we have clients/drivers(?) that automatically dial down their power and thus create less interference?
I've been using patch antennas in my house for years.
Got them used off ebay for next to nothing.
Glad to see the best and brightest at an institute of higher learning are finally catching on.
{facepalm}
...then they could use directional antennas on cell base-stations and divide up each cell into slices!!
Hey they could call them "sector antennas" and... oh never mind.
[FrLz]
and in a professional manner works better than getting some intern who once set up a single ap for there parents to deploy a large scale wifi system - I am amazed i though wifi had magic unicorns that made it perfect!
This is similar in the US, but it varies slightly based on frequencies, locations, and environment.
Great Info. Thanks for the your effort. Appreciate it.