Three common Wi-Fi myths about capacity, interference and roaming

It’s time to clear the air about Wi-Fi. Once you sort out some common misconceptions, a lot of the fogginess around Wi-Fi dissipates. Let’s look at three common Wi-Fi myths about capacity, interference and roaming.

The same laws of physics (specifically electromagnetism) that govern radio and cell phones also govern Wi-Fi. Which means that certain things about Wi-Fi behavior are predictable.

Wi-Myths about capacity: Higher capacity means an AP talks to more devices at the same time 

How many devices can an AP talk to at one time? The answer is always the same: one.

So how does an AP appear to be talking to many devices concurrently? And how do Ruckus APs support greater capacity than other APs?

You know what it’s like to talk to people at a noisy party? You can’t make out what everyone is saying when they’re talking at the same time. If APs liked to party (and who’s to say they don’t?), they’d appear to be talking to everyone (everyone being devices) simultaneously. What they’re actually doing is listening or talking to each device in turn, but doing it at superhuman speed.

That’s not all there is to this super-cool party skill. The AP-device conversations are also based on assumptions that each “conversation” will be brief. A request to connect. Done. Request to download. Done. Request to upload. Done. In other words, devices aren’t talking to the AP continuously. It’s just a constant, super-fast series of interactions.

So how does a Ruckus AP achieve superior capacity? (Independent analyst testing shows Ruckus beats competitors in video QoS and data throughput.) That’s where we depart from the norm. Not the laws of physics (those still hold for everyone, thankfully). But Ruckus invests in the development of sophisticated RF software where other companies may use off-the-shelf firmware.

We optimize the processing capabilities of our APs. Our APs are, in essence, faster or more efficient (depending on how you look at it) at handling concurrent connections. We also use algorithms to factor in how much capacity is required for things like buffering streaming video.

BeamFlex+, which is our Adaptive Antenna Technology, also plays a role in capacity. The AP’s antenna, working in an omnidirectional mode, can detect a client trying to connect from, say, the edge of a room. It can then adapt the antenna to a directional mode to get a stronger signal to that device.

Wi-Myths about Interference: Add more APs to get more capacity

Here’s why it’s important to understand this law of physics—because you don’t want a Wi-Fi designer to tell you that putting two APs close to each other will necessarily increase capacity. Remember that devices have to wait their turn to talk to an AP. If two APs share the same channel, they’re going to create interference, not extra capacity. It doesn’t matter if there are two APs or two dozen: if they share the same channel, only one will transmit at any given moment. The others are just hanging out (literally).

Wi-Myths about Roaming: It’s not about APs dropping the ball (or signal)

Have you ever lost a call on your cell phone when moving between cell towers? Roaming is a wonderful feature, but usually not during that handoff period. It’s a common misconception that the APs are in charge of roaming—that they call out to devices, “Hey, disconnect from that AP and connect to me now!” That would make APs great air traffic controllers, but that’s not their job description. Or in those pesky laws of physics.

It’s actually the devices that look for connections to the closest AP. But devices don’t have the connection smarts that APs have. As a result, they can be really clumsy about disconnecting from one AP and connecting with another. Sorry devices, but those dead spots and garbled channels are on you.

Ruckus does apply a couple of proprietary AP technologies that make roaming more seamless. One of these clever techniques is SmartRoam+: as a device begins to move away (roam) from an AP, the signal weakens. The device should look for a stronger signal, right? But often a device will hold on until the signal has gotten really bad. Before it reaches that point, however, the SmartRoam+ technology will sing out to the device “Let it go!” and disconnect it from the fading AP. The client will search for—and find— a closer AP with the stronger signal.

It’s good to dispel the myths about Wi-Fi. It can help you avoid mistakes in design. It can also help you appreciate how smart design—without messing with the laws of physics—can give you better Wi-Fi.

 

 

Jeanette Lee
Jeanette Lee

Sr. Director of Global Field Enablement When listening to music, you will catch me listening to Pink and Rush as my #1 song that's played on my playlist is "Are We All We Are," by Pink. However, as much as I love music you will never catch me singing karaoke. I also love a good book. My favorite book at the moment is "Unpronounceable" by Susan diRende. And while strolling through life, my favorite quote is, "No matter where you go, there you are."

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