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

Let’s look at three common Wi-Fi myths about capacity, interference and roaming. Dispelling myths 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.

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 access point 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 access point appear to be talking to many devices concurrently? And how do RUCKUS access points support greater capacity than other access points? 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 access points 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 access point-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 access point continuously. It’s just a constant, super-fast series of interactions.

Access points optimized to handle concurrent connections

So how does a RUCKUS access point 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 access points. Our access points 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 access point'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 access points close to each other will necessarily increase capacity. Remember that devices have to wait their turn to talk to an access point. If two access points share the same channel, they’re going to create interference, not extra capacity. It doesn’t matter if there are two access points 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 access points are in charge of roaming—that they call out to devices, “Hey, disconnect from that access point and connect to me now!” That would make access points 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 access point. But devices don’t have the connection smarts that acess points have. As a result, they can be really clumsy about disconnecting from one access point and connecting with another.

Connecting to the access point with the strongest signal

Sorry devices, but those dead spots and garbled channels are on you. RUCKUS does apply a couple of proprietary access point technologies that make roaming more seamless. One of these clever techniques is SmartRoam+: as a device begins to move away (roam) from an access point, 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 access point. The client will search for—and find— a closer access point 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.