Effectively it is being argued that Ruckus technology (adaptive antennas, ChannelFly etc) has no effect on performance in a classroom environment because all of the 30+ iPad devices in the classroom are limited by their downstream throughput which is about 25Mbps. In Aerohive’s “Need for Speed” blog they state that these iPad consume about 80% of the airtime even though they are moving at relatively slow speeds by today’s standards. I haven’t personally tested this but I believe these numbers.
Now, my response.
First off, I work for Ruckus and this blog is Ruckus centric. I’ll try to not make a habit of it. Promise.
One of the things that I have stressed with all of my Wi-Fi students over the years is to look at a Wi-Fi network as a whole organic structure. Understanding the protocols and RF between an AP and a client are essential but the next step is to understand how each Wi-Fi device (STA or AP) effects each other. We don’t live in a world with one AP.
High Density Myth #1: Adaptive Antennas (BeamFlex) doesn’t help the throughput of an iPad.
True (yes, you read it right). If you test one iPad with one AP within 10 feet of each other in a clean environment, you’ll probably get similar results from most vendors including Linksys and Netgear. Unfortunately for those vendors, that situation only exists in poorly thought out tests.
BeamFlex is an adaptive antenna technology that customizes signals in both direction and polarity to optimize the signal for the client device. That is what BeamFlex is most known for anyway. However, one of the significant but unsung benefits of adaptive antennas is the reduction of co-channel (AP to AP) interference.
Imagine that you install one AP per classroom like is recommended by most vendors. Now you have a multitude of APs within close proximity of each other. If they follow their standard channel plan of 1,6,11 then you will have significant co-channel interference because you bought too many APs. And, don’t give me that crap about reducing transmit power for “smaller cells”. That only works so so and if you reduce the transmit power enough to make a real difference then you reduce the data rate to the client devices creating a new host of problems.
Signal control while maintaining appropriate transmit power reduces co-channel interference while keeping data rates high.
High Density Myth #2: Channel selection is simple
The “standard” channel plan is to use 1,6 and 11 and change channels when some arbitrary measurements hit a pre-determined threshold. Ruckus invented a technology called ChannelFly that works off of a very simple measurement. Capacity. Each AP selects the channel that gives it the best possible throughput and network capacity. It’s secret sauce how this happens but it really makes a difference. Don’t trust me, try it in real life (I hate lab environments).
High Density Myth #3: More clients equals more APs
One of the most common and significant mistakes in Wi-Fi network design is installing too many APs. Ask any independent Wi-Fi consultant and they’ll tell you that they have, at some point in their career, turned APs off in order to improve the network. Is one AP per classroom appropriate? Only in limited cases. Many factors must be present before I recommend one AP per classroom. Many vendors arbitrarily and consistently recommend this and I do not agree with this practice.
More than likely you will test each vendor’s Wi-Fi gear before you buy. I highly encourage it. However, here is what I ask of you. If you want to test one AP in a classroom that is fine but if you want to see real results, test in as real of an environment as you can. Install 6+ APs, stress them all and observe the overall network performance.
Each vendor puts focus on solving a different problem. Some problems are real and some aren’t. Ruckus is the Ferrari/Lamborghini/McLaren F1/Bugatti/Ducati of the Wi-Fi world because that is where we put our focus. Ruckus has more Wi-Fi engineers than Aerohive, Xirrus, Meru and Meraki combined. Ok, I made that up (blogs do that) but I bet I’m not far off. 🙂