Top 10 Tuesdays: 10 things you should know about Wi-F 6

I write a regular series around technical topics called Top 10 Tuesdays. If you missed some of the posts in the series, this is a handy place to find them.

#1: Going faster, ain't the point.

Although it boasts very fast speeds, the point of Wi-Fi 6 wasn't to create faster connections. The main driver was efficiency. Older Wi-Fi standards are like a delivery service that brings one box to one location, drives backs to the warehouse, picks up another box, and delivers that. Repeat until the world runs out of fossil fuels.

Wi-Fi 6 is more like UPS, cramming as many packages in the truck as can reasonably be delivered in one go. Both trucks go roughly the same speed, but more packages (data) get delivered in the second case.

One way Wi-Fi 6 does this is via an OFDMA (Orthogonal Frequency-Division Multiple Access) mechanism called resource units or RU. In older Wi-Fi standards, transmitting devices would use a fixed width channel to transmit. The size of the channel determines how much data can be sent, but what if every device doesn't need that much bandwidth?

With Wi-Fi 6, you can slice the channel into smaller bits (RUs). Just like your delivery guy becomes the jigsaw champion through figuring out how to stack packages for the entire neighborhood in one truck, Wi-Fi 6 assigns RUs so multiple devices send data at the same time.

#2: Let sleeping devices lie

Next to better cameras and lighter weight, battery consistently ranks in the top 3 reasons people upgrade devices. Poor coverage for wireless (Wi-Fi, Bluetooth, and LTE) has always impacted battery life. There's nothing like a device constantly scanning for a better signal to drain battery life and warm up the device with the heat of the sun. Ouch.

Wi-Fi 6 is unique among the many Wi-Fi standards in that it improves battery life instead of only existing to make your life worse. How much battery life a device in sleep mode conserves depends on how long it stays asleep. Wi-Fi 6 aids this through sophisticated mechanisms (called Targeted Wakeup Time or TWT) that allow devices to go into sleep mode faster and stay sleeping longer.

Older versions of Wi-Fi have power save modes, but only allow brief periods of inactivity. They're also under the control of the AP. The client gets little say. With TWT, a client can request a wakeup based on any schedule or time it wants.

The end result is a cure for insomnia that you never knew your smartphone suffered from. Keep that warm milk, fluffy bunny slippers, and bubble bath for yourself. Your phone definitely won't enjoy them.

#3: Dense doesn't mean stupid

One way Wi-Fi 6 increases overall capacity is how it sends information. Transmitted data is modulated. The receiver demodulates it and put the bits back together. There are multiple modulation schemes. A good way to think of them is by the density of data they can send. Different modulations are represented by a 2x2 grid called a constellation map. In that grid are dots representing the density. The more "points" fit into the grid the more data gets sent. The images below show two modulations, 64-QAM (8x8) and 1024-QAM (16x16) which is new for Wi-Fi 6.

But there's a catch. The constellation map is like a dart board. Bigger circles are easier for the device to hit a bull's eye and successfully demodulate the data bit. More dots in the same space get smaller and harder to hit. If the receiving device misses too many of them, it loses data. Imagine moving the dartboard further away and dimming the lights. That's what too much RF noise and distance from the AP does.

One of the reasons clients don't operate at their maximum speed is they're too far from the AP and can't distinguish the data well enough. They need bigger targets, which means lower data rates.

#4: Beat the crowds

It's a beautiful day. You're driving along, rocking out to the radio. Eventually, you get close to another station on the same or adjacent channel. Your radio station starts fading in and out and overlapping with the other. Those awesome tunes become impossible to listen to. Wi-Fi works exactly like that. Except your car transmits too. EVERYONE'S's car transmits. Oh, and you can't pick which channels the other cars are using. Might be using yours.

Welcome to the RF engineer's world. Don't forget to buy a souvenir t-shirt on your way out.

Anything that isolates wireless devices from each other is gold. Only two things do this: assigning channels far enough apart they don't overlap or weakening the signal with distance or obstacles. There's limited channels however and devices are crammed together. Think LA rush hour and only 20 channels for all the radio stations and cars. Ouch.

Wi-Fi 6 opens up more sweet RF spectrum in the 6 GHz band (6E). Fantastic news BUT (you knew there was a but right?) there's no client support yet. We've all got AM-only radios, not FM. Clients WILL be coming. When they do, we can relax in glorious, uncluttered spectrum.

#5: Beam me up

You can't cheat physics, but if you understand it well enough, you can bend the rules. As a half-duplex technology, Wi-Fi works best if one devices talks at a time on any particular channel. Wi-Fi 5, introduced multi-user MIMO (MU-MIMO). The AP bends the rules by transmitting to multiple devices at once. Still one device talking, but multiple devices are getting data. Awesome.

Wi-Fi 6 said "Hold my beer" and introduced uplink MU-MIMO. Now you've got multiple devices transmitting at the same time (uplink) to the AP. The magic happens because the AP slices up airtime and schedules when, how, and which devices transmit. This is very different than the chaotic free-for-all melees of prior versions.

Uplink MU-MIMO brings efficiency and additional capacity. It requires all devices be Wi-Fi 6 capable, so don't expect most current devices to know this trick. Another requirement will be major smarts from the engineers designing this stuff. Designing the algorithms to make this work is non-trivial. We are fortunate at #CommScope to have some amazing engineers with plenty of experience already in bending the rules of physics with technologies like RUCKUS BeamFlex.

#6: It's not a party if nobody shows up

Wi-Fi 6 has a ton of new features, but they require a Wi-Fi 6 AP and client device. How to justify buying that shiny new Wi-Fi 6 AP if you don't have clients yet?

Technically, there are a few Wi-Fi 6 clients out there: iPhone 11, the Samsung S10, and some PCs all support the latest standard. But that's like throwing a party and only your mom and the kid next door show up.

Every spin of new silicon for a Wi-Fi chipset benefits from lessons learned by the manufacturer. They get a little better overall which helps everybody. Another way to benefit from Wi-Fi 6 today: take it outside. Wi-Fi bridges and mesh networks connect buildings when there's no cable infrastructure. They carry all kinds of traffic, some of it incredibly sensitive like voice, which always benefits from performance improvements. When multiple Wi-Fi 6 APs connect to each other, the improvements are a faster, more reliable link. If you're stuck on the other side of a wireless bridge or mesh, that's nothing to sneeze about.

#7: Making order from chaos

Wi-Fi gets a bad reputation as a first-come-first-served protocol. Every device contends with the others (including the AP) for airtime. In order to watch that cat video, your device must first get into a melee-style battle royale with everyone nearby that might also want to transmit. The winner gets to transmit. As soon as they're done, the fight starts all over again. Yikes. Who knew networking could be so violent?

Wi-Fi 6 incorporates many technologies that aid in avoiding this needless bloodshed (air-shed?). In particular, OFDMA (new in Wi-Fi 6) allows the AP to chop up transmission channels into smaller sub-units called Resource Units (RU). This helps the AP control who transmits and when. Instead of that free-for-all melee, there's a reasonably polite line waiting their turn. Far more efficient and boosts overall performance, although the TV ratings aren't nearly as good.

Who knew Mom was right all along when she told us to be polite and wait our turn?

#8: Coloring outside the lines

Wi-Fi 6 introduces a new concept called BSS coloring. A Basic Service Set (BSS) is the ID of a wireless network transmitted by an AP. If multiple APs transmit the same network name, collectively they are called an Extended Service Set (ESS). When there's more than one AP, hi-jinks often ensue. In particular, devices transmitting on the same channel interfere with each other.

With BSS coloring, each AP picks a number (not a color name, sadly) to identify its BSS in the preamble. If the AP or one of its connected devices detects a transmission on the channel, it checks the transmission's color. If the color is the same, it's an Intra-BSS packet. A different color is considered an Overlapping BSS (OBSS). Distinguishing between BSSs on the same channel could help APs and devices decide when to transmit in the presence of interference.

Wondering how it works? Me too. The standard lists 3 different ways to use color. The WFA does not (yet) test this however. Until they do, there's unlikely to be multi-vendor interoperability or real world use.

In the meantime, we can only hope they change their mind about "midnight blue" or "twilight sparkle" instead of numbers.

#9: It ain't the size, it's how you use it

Wi-Fi 6 moves away from the pursuit of ever bigger throughput numbers and it's about ducking time. Nobody needs a 9.6 Gbps PHY rate. I can't think of a really good application and I'm constantly told I have a great imagination. ??

What you DO need is opportunity and reliability. The amount of data the average device needs to transmit is disappointingly small if you've got your heart set on gigabit speeds.

So how, you might ask, do you tell which AP is the best if size isn't king?

There's no easy answer.

Networking IS a numbers game. I did an entire Top 10 series on it. Buying an AP solely by potential max throughput is like hiring a cargo plane to haul one suitcase.

You need an AP that offers more opportunity and reliability: opportunity for your device to transmit/receive any time necessary, and the ability to do so reliably and repeatedly. Throughput isn't everything, which is why enterprise Wi-Fi manufacturers like #ruckus #commscope spend so much R&D on work not directly related to throughput improvement. The reliability, scalability, and flexibility we're known for provides performance that's more than a single number.

#10: To buy, or not to buy

The value of upgrading to Wi-Fi 6 saturates tech news like spilled coffee on your new shirt. This #Top10Tuesday series examined those claims. Many have merit, some not so much. When asked whether they should upgrade or not, these posts represent the detailed answer I give to that question. TL;DR if you rely on Wi-Fi as a primary communications strategy and are buying soon the answer is "yes".

If you choose to upgrade however, be informed. Do it for the right reasons: not because Wi-Fi 6 is +1 better than Wi-Fi 5 or because of higher throughput rates. Do it for the truly impactful improvements that bring Wi-Fi one step closer to the deterministic, reliable connection people, apps, and businesses require. When you look to that future purchase, I hope you give Ruckus a consideration.

Thanks for following this series!