WiFi AC and MIMO, how these technologies improve the WiFi connection


If you are looking to buy a new device, be it a smartphone, tablet or computer, or you have been recommended to change the router that your operator puts in to improve WiFi coverage, it is very likely that you are dizzy with the large number of symbols and terms that they are used when talking about a wireless connection. WiFi is a complex world , full of strange nomenclatures, new standards that have appeared over time and that improve transfer speed and even technologies that focus on improving coverage. Within these technologies, and that you have surely heard of, we have AC WiFi and MIMO technology . With these two technologies we will achievehigher speed, greater coverage and greater stability in our WiFi connection . We are going to review what these technologies consist of and how they can help us achieve the highest speed of our connection without using cables .

At present, who more and who less, we have at home several devices connected to the Internet by WiFi . What's more, many users have never connected anything by network cable to the router. It is normal, WiFi has become so common in our day to day that many users see cables as "something of the past" . However, the complaints come when it comes to getting the maximum internet speed through WiFi . Many users complain to the operators that their brand-new 300 megabytes of fiber connection just contracted does not reach them via WiFi and they do not understand why. To understand it, the first thing we must know are the different standards with which WiFi routers work andwhat conditions must be met to achieve maximum speed .


Today we want to talk about WiFi AC and MIMO technology . The WiFi AC standard was officially approved in January 2014 and has been incorporated by many routers since then. Even some operators already include this technology in the routers that they place their clients, especially if we have contracted a fiber connection. The most common standard until now was WiFi N , a technology capable of reaching a maximum transfer speed of 300 Mbps . WiFi AC technology offers several advantages over this standard:

  1. Three times faster than WiFi N
  2. 1 Gbps minimum speed
  3. No cuts thanks to the use of the 5 GHz band
  4. Multiple simultaneous connections

In order to enjoy the high speed of AC WiFi connections, we will not only have to have a router that incorporates this technology, the equipment will also have to be compatible . How can we know if a team is compatible? In the specifications of our devices we will have marked what type of WiFi it uses in this way: 802.11 b / g / n / ac . The different letters that accompany the numbers mark the multiple wireless standards that have appeared over the years, each one faster than the last. If this specification the letters "ac" do not appear it is that our device is not compatible with this technology .

The b, g and n standards use the 2.4 GHz band , which is fully saturated , as well as being more sensitive to electromagnetic emissions . The WiFi AC standard , however, uses the 5 GHz band , which is currently much freer and is also less sensitive to electromagnetic emissions . This will allow us to make the most of the speed of our internet connection and, if we have several computers at home, achieve much higher transfer speeds between computers . Of course the WiFi AC standard is compatible with the rest of the older standards, so we won't “ditch” the old teams.

BeamForming and MIMO


To understand the improvements that the WiFi AC standard can bring us, we must talk about two technologies: BeamForming and MIMO . While WiFi N routers broadcast the WiFi signal around them , BeamForming technology  directs the WiFi signal directly to the devices . On a practical level, this means less signal loss due to obstacles that we can find between the devices, such as walls, ceilings or doors.

MIMO stands for “Multiple Input Multiple Output” and it is a technology that allows greater wireless coverage , in addition to providing us with greater speed by using several antennas simultaneously . However, MIMO technology is not exclusive to AC WiFi routers, MIMO appeared alongside the 802.11n standard . What's more, all 802.11n routers have MIMO . However, depending on the antennas that the routers have, we can have different MIMO configurations, such as 3T3R (3 antennas to transmit, 3 antennas to receive). The technology used by the N standard is called SU-MIMO , that is, data streams are only transmitted and received by a single device at a time .

However, although MIMO technology is not exclusive to the WiFi AC standard, it has improved it substantially. How did you do it? Implemented the so - called MU-MIMO . MU-MIMO technology  allows multiple devices to simultaneously receive different streams of data , thus increasing the speed and performance of the network. This technology, in addition to allowing data to be sent simultaneously, takes maximum advantage of bandwidth so that all devices achieve maximum speed .


With MU-MIMO technology , the router allows to send a stream of data to each of the clients, so the data will be sent simultaneously and the bandwidth will be used to the maximum . If we are using, for example, three devices, all three will send and receive data at the same time (in parallel) and not in series as it happens with SU-MIMO (Single-User MIMO) technology .

However, MU-MIMO technology also has its limitations. For example, it currently only works with wireless downlink connections . This means that only wireless routers and access points can simultaneously send data from multiple users , either one or more data streams to each. The "client" devices , such as smartphones, tablets or computers, will have to wait their turn to send data to the router or access point. This makes MU-MIMO technology much more effective when downloading than uploading data to the network .

Another minor drawback is that, just as SU-MIMO technology works in the 2.4 GHz and 5 GHz WiFi frequency bands, MU-MIMO only works in the 5 GHz band . Also,  a MU-MIMO router cannot serve data streams to an unlimited number of devices at the same time . Currently, these routers can supply data in this way to a maximum of 3 or 4 computers. Lastly, only wireless devices with built-in support for MU-MIMO can receive MU-MIMO signals .

I want to switch to WiFi AC, what do I need?


If after reading this article you are determined to switch to the WiFi AC standard , you need to know what you need to do to do so. The standard is compatible with any fiber and ADSL connection , so you will not have problems in that. The first thing we will need is, obviously, a router with WiFi AC . If you start looking for a router with AC WiFi, you will realize that there are many different types, and at many prices. The big difference between them, in addition to all the extra options they may include, is the maximum connection speed . For example, an AC 1900 WiFi router will achieve a maximum speed of 1,900 Mbps . On the other hand,the performance offered by the WiFI AC depends on the antennas involved . The more antennas, the higher the speed . While it is true that we can spend good money and buy a router with many antennas, we must bear in mind that the receiver will also have to have them . The vast majority of 802.11ac compatible smartphones usually only have one antenna , so it will be impossible to reach the maximum speed of the router.

As we do not want to discourage anyone, it is fair to say that, although your devices do not incorporate the maximum number of antennas and you cannot reach the ultra-fast speeds that the most current routers mark, just by having devices with WiFi AC we will already notice an increase in performance on the really important connection . And if any of your devices are older or lower-end and still use the WiFi N standard, or even WiFi G, no problem, since AC routers use dual band to be compatible with any device .