September 22, 2016
By Ted Needleman
Wired Ethernet still has a lot going for it. It’s fast, and for the most part, secure. Still, over the years, many offices have added Wi-Fi to the network mix. And, as technology improves, and the years pile onto your equipment, eventually it will be time to replace older equipment such as routers and access points with something newer, and hopefully better in some way.
When you look at Wi-Fi equipment right now, you will see most vendors touting their MU-MIMO capabilities. This is an evolution of the latest dual-band 802.11ac protocol. 802.11ac equipment operates on the 5MHz frequency band, and offers multiple channels and much higher transmission speeds than 802.11n.
MIMO is an acronym for multiple input, multiple output. The simple explanation of MIMO is that it can transmit to a device and receive from a Wi-Fi device at the same time (the technical term for this is full duplex). Routers and access points without MIMO are half-duplex devices, and have a much slower throughput which bogs down even further when there are multiple Wi-Fi devices contending for bandwidth. A MIMO router/access point actually has multiple antennas. Sometimes these are contained in the case and are not visible, other times they stick out, making the router look like a giant insect on its back.
802.11ac is backwards compatible with 802.11n (which is also backward compatible with even earlier Wi-Fi protocols), so if you replace aging equipment with 802.11ac models, you’ll get better throughput and less loading on the router when using laptops, smartphones, and tablets which are 802.11ac capable, and still be able to use any 802.11n equipment that you may have.
MIMO by itself increases the data transmission speed between the router and a single MIMO capable device. But it still has to switch between all of the Wi-Fi devices that are currently connected to the router or access point. That’s where MU-MIMO (multi-user MIMO) comes in.
As its name suggests, MU-MIMO provides full-duplex MIMO support to multiple devices (usually three at the same time). That means a lot less switching to give each Wi-Fi device on your network its time in the Wi-Fi bandwidth sun. And MU-MIMO is usually good at allocating that bandwidth to provide each device with the amount it needs for the tasks that are being supported.
Looking at the right specs
So which technology (and price range) should you be looking at? If you’re like many small to mid-size practices, it will probably be MU-MIMO. The confusing part of making the decision is that MU-MIMO devices are generally being pushed by vendors as being superior for streaming to multiple devices. And unless your practice is somewhat atypical, you’re probably not doing all that much streaming. At least you probably hope that your staff is actually working rather than watching YouTube video of cats playing piano. Further confusing the issue, many 802.11ac routers, access points and USB dongles are actually MIMO capable right now, they just don’t have the slightly newer, and usually more expensive, MU-MIMO capability.
Where MU-MIMO really comes into play is in offices that have a lot of Wi-Fi devices. That’s not as unusual an occurrence as it might seem at first glance. A typical employee might have three or four Wi-Fi devices – a smartphone, tablet, laptop and even their desktop might all be vying for Wi-Fi bandwidth. And that’s just for one employee. Even a small office can have 20 or 30 devices, though not all of these devices will be contending for router bandwidth at the same time.
Assuming that the Wi-Fi devices are MU-MIMO compatible (and that’s not a given), A router with MU-MIMO capabilities will usually do a better job of supplying each Wi-Fi device the bandwidth that it needs at the moment than will a less expensive, and less capable model.
But there are a few “gotchas” in this decision. The first is that many slightly older devices simply don’t have the ability to make effective use of MU-MIMO. Most newer iPhones, iPads, and Android devices do have MU-MIMO capability, but those that are several years old, probably don’t. And unless both sides of the connection are MU-MIMO capable, you’re not going to see any great improvement in throughput over less expensive single-user MIMO.
The real bottom line
The second “gotcha,” and the real decision point, is what do you expect to gain from the upgrade? If you are moving from an 801.11g or 802.11n router to an 802.11ac router, and have devices that can take advantage of AC technology (or are willing to upgrade those devices with USB ports with 802.11ac plug-in dongles, you may see a noticeable increase in network response from your Wi-Fi devices. And if you are replacing a router that’s starting to go, dropping out or turning off at times, then 802.11ac compatible routers are not that much more expensive than those that use the older (and slower), 802.11n technology.
But when you go shopping, keep in mind that in a typical office setting, speed is usually not the important factor. Being able to support a fair number of devices without having the network bog down from the load is. And actually being able to measure this in your office before you make the decision is nigh impossible, so you’re essentially rolling the dice.
The thing that makes the decision even more difficult is that most MU-MIMO routers and access points are, at this moment, considerably more expensive than are 802.11ac single-user MIMO devices. That cost differential can be as much as a hundred or more dollars.
Still, even if your current Wi-Fi devices aren’t MU-MIMO capable, odds are that their replacements will be, so you may want to invest in the future and extend the useful life of a current replacement and purchase. And medium sized businesses with a substantial number of 802.11ac and MU-MIMO compatible devices should see the network balance its load a bit better as older routers, access points, and the Wi-Fi devices that connect with them, are replaced with MU-MIMO capable devices.