When many friends buy routers, they often see advertisements from merchants "N(N>4) antenna, the signal is better through the wall king, super fast! “
Is it true that the more antennas the better the faster the signal?
This is what we are going to talk about today about MIMO technology.
Just like the reason why a punch superman becomes stronger, the router does not become stronger because of more antennas, but because of MU-MIMO, the router with more antennas has the opportunity to become stronger.
First of all, the conclusion: buy a router networking, you should do so
The router does not look at the number of antennas, look carefully at how many MU-MIMO it supports
If your budget allows, you can buy a Wi-Fi 6 router directly, even if it is a 2.4GHz device
If the router is a directional antenna, when networking, remember to pair the antennas according to the left and right relationship, respectively, at an angle of 45 ° and 135 °
As for why?
And listen to us slowly.
Boring MIMO explanation
Let's take a look at the academic MIMO explanation:
MIMO (Multiple-Input Multiple-Output, multiple input, multiple output) technology refers to the use of multiple transmit antennas and receiving antennas at the transmitter and receiver respectively, so that the signal is transmitted and received through multiple antennas at the transmitter and receiver, thereby improving the quality of communication. It can make full use of space resources, through multiple antennas to achieve multiple transmissions and multiple receipts, without increasing the spectrum resources and antenna transmission power, can be multiplied system channel capacity.
The little lion translates it, in fact, it is a sentence: let the network signal pass through different ends (in the router, generally the antenna), to achieve the transmission of multi-channel network signals.
Route the secrets of caton and multi-antenna myths
Often readers and friends ask us, why do more people use routers, they will feel the network card?
Of course, there are many reasons for this, such as the processing capacity of the router network chip, the size of the memory, the ability of the device with the machine, the total capacity of the backplane bandwidth, the quality of the signal, and so on...
However, a core reason is how wireless routers used to work.
The 2.4GHz era of wireless routers adopts SU-MIMO technology, that is, "single user more in and more out" technology, in fact, when the router is working, it is to queue up all connected devices, and then according to the logic of the processor and firmware, one by one, or take turns, to issue network requests to implement each device.
In the 2.4GHz era, routers actually take turns to serve each device, and the more devices there are, the more obvious the delay feels (Figure: powercert videos)
When there are few connected devices and the workload of the devices is very low, such as when everyone is browsing the web, the gap time between this switch and rotation is of course very short, short enough to be ignored, giving people the feeling of "always networking", and the experience is good.
But when there are more connected devices, and the workload is very large, such as 10 people are all watching 4K HD online video, the APP must buffer 15 seconds of video content by default, and 10 people download "Squid Game" at full speed in Thunderbolt - that is the same as queuing up to eat, the better router logic is the same as Haidilao, you can also have a little tea snacking and drinking, how much to maintain the basic network experience, almost let your APP circle directly - wait until the previous device network request is completed.
And this MIMO technology is the origin of the myth that "the more antennas, the faster the speed": each antenna can be independent of a road, and then let everyone's equipment queue.
"In the case of the same number of people, the more ticket windows, the shorter the queue waiting", is it the same reason?
This is where the multi-antenna myth came from during the long reign of 2.4GHz wireless devices.
Therefore, there are also unscrupulous manufacturers and merchants together, in the case of firmware support, by doing multiple antennas or even fake antennas, giving users an illusion, buying a router with more antennas must be good - in fact, the low-end network chip router with 8 antennas may not be as good as the router with 2 antennas of the powerful network chip, after all, the latter processes and completes network requests faster!
MU-MIMO, the symbol of the Wi-Fi 5 era
In the 5GHz Wi-Fi5 era of 802.11ac, MU-MIMO technology was finally introduced, that is, "multi-user, multi-in, more out" technology.
At this time, each transceiver unit (still generally independent of the antenna) can independently serve a (or batch) device, plus the large bandwidth capability of 802.11ac, from 54Mbps at 2.4GHz to 300Mbps+ at 5GHz, so that users feel a real speed increase -
"There are still so many people, the ticket window is not only more, but also open at the same time, and each window is a ticket vending machine, and the ticketing capacity is more than 5 times the original", is it the same reason.
5GHz routers can serve multiple devices at the same time, in the case of a small number of devices, equivalent to a single device with a single "router" in service (Figure: powercer videos)
One might ask, if you exceed Wi-Fi 5's 4x4 service standard, don't you still have to queue up?
This is the benefit of the 5GHz standard, at this time, the device that shares a signal transceiver, in most firmware solutions, will be "shared", rather than "waiting" For this way to connect the network capabilities, that is, the experience is weakened, but it will not become a long-term delay like 2.4GHz.
Wi-Fi 5 MIMO disadvantages, I Wi-Fi 6 to solve
"Well said, why do I still want a Wi-Fi 5 router or a card?"
"Why is the signal of 5G routers inferior to 2.4G?"
Yes, I believe there must be friends who want to ask questions from the soul.
This involves several features of Wi-Fi 5 that affect the use of MU-MIMO technology:
In the Wi-Fi 5 standard, MU-MIMO only operates in the 5GHz band, and users in the 2.4GHz band continue to queue up
Not all Wi-Fi 5 routers support MU-MIMO by default
Most cheap Wi-Fi5 routers, even if they support MU-MIMO, only support a minimum of 2x2 MU-MIMO, that is, only two simultaneous transceiver and sending capabilities, limiting the service capability
After 5GHz and MU-MIMO are enabled at the same time, the transmission of the antenna signal has directionality, called "Beamforming", so some directions and positions, due to the problem of signal incidence angle, the penetration is greatly reduced, but the signal bandwidth capability is still large. The 2.4GHz signal transmission is omnidirectional, coupled with the inherent penetration of low-frequency signals... In simple terms, from the density point of view, the 5GHz signal is the nature of the flashlight, and the 2.4GHz signal is the nature of the light bulb (so the antenna multi-signal good myth can be rested, everyone is a omnidirectional signal, there is also cross interference!). ）。
Wi-Fi5 MU-MIMO only supports 4x4 MIMO up to a maximum.
Wi-Fi5 MU-MIMO only works for the download link, and the upload link is still the old working mode, so it does not mean much to the host.
MU-MIMO is also supported for the user's device. In fact, for a long time, non-flagship mobile phones did not support MU-MIMO.
These problems have led to the embarrassment that although MU-MIMO is good, users do not have a strong sense of experience in the Wi-Fi 5 era. Fortunately, we finally ushered in Wi-Fi 6, 802.11ax. In addition to the stronger bandwidth capability, the Wi-Fi bandwidth capability is increased to more than the AX3000 level, and the biggest change is the specific support for MU-MIMO. Wi-Fi6 achieves up to 12 MIMO capabilities, including 4 2.4GHz MIMO and 8 5GHz MIMO capabilities.
Up to 8x8 5GHz MU-MIMO plus 4x4 2.4GHz MU-MIMO, is a huge change for Wi-Fi6 (Figure: powercer videos)
The most penetrating 2.4GHz can finally catch the MU-MIMO!
"The same number of queues, not only the ticket window has increased, and even some windows are manual + machine automatic ticket sales, and even two people can line up a window at the same time (large bandwidth link sharing), buy tickets faster!"
Isn't that true?
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