Wifi ac what it means

The 802.11n standard has three modes: High Throughput (pure 802.11n), Non-High Throughput (fully compatible with 802.11b/g) and High Throughput Mixed (mixed mode).

AC standard Wi-Fi. Why an AC router is better than an N router

When you buy a 5GHz router, the word DualBand distracts our attention from the more important point, the Wi-Fi standard that uses the 5GHz carrier. Unlike the 2.4GHz carrier standard that we already know and understand, 5GHz devices can be used in conjunction with 802.11n or 802.11ac standards ( hereinafter AC standard and N standard).

The IEEE 802.11 group of Wi-Fi standards has evolved quite dynamically, from IEEE 802.11a, which provided speeds up to 2 Mbps2 Mbps, through 802.11b and 802.11g, which gave speeds up to 11 Mbps и 54 Mbps respectively. Then 802.11n or simply the n-standard appeared. The N-standard was a real breakthrough, since it was now possible to transmit traffic at the then unthinkable speeds through a single antenna 150Mbit.. This was achieved through the use of advanced coding technology (MIMO), more careful consideration of RF propagation, double channel width technology, non-static guard interval defined by such concepts as modulation index and coding schemes.

Operating Principles of 802.11n

The familiar 802.11n can be used in either of the 2.4GHz and 5.0GHz bands. On the physical layer, in addition to improved signal processing and modulation, it adds the ability to transmit simultaneously over four antennas, through each antennae can transmit up to 150Mbit/s, i.e. it is theoretically 600Mbit. However, given that the antenna is simultaneously working either for reception or for broadcasting, the data rate in one direction will not exceed 75Mbit/s per antenna.

Multichannel Input/Output (MIMO)

This technology was first available in 802.11n. MIMO stands for Multiple Input Multiple Output, which stands for Multiple Input Multiple Output.

MIMO allows multiple data streams to be simultaneously received and transmitted over more than one antenna.

The 802.11n standard defines different antenna configurations from "1×1" to "4×4". Non-symmetric configurations are also possible, such as "2×3" where the first value means the number of transmitting and the second the number of receiving antennas.

Obviously, the maximum transmission reception rate can only be achieved by using the "4×4" scheme. Actually, the number of antennas does not increase the speed by itself, but it allows the application of various advanced signal processing methods, which are automatically selected and applied by the device, including based on the configuration of antennas. For example, the "4×4" scheme with 64-QAM modulation provides speeds up to 600 Mbit/s, the "3×3" and 64-QAM scheme provides speeds up to 450 Mbit/s, and the "1×2" and "2×3" schemes up to 300 Mbit/s.

Channel bandwidth of 40 MHz

A feature of 802.11n is a feature of the 802.11n standard is the doubled bandwidth of the 20 MHz channel, i.e. 40 MHz. 802.11n can be supported by devices operating on 2.4GHz and 5GHz carriers. While 802.11b/g only works at 2.4 GHz, 802.11a works at 5 GHz. In the 2.4 GHz band only 14 channels are available for wireless networks, of which the first 13 are allowed in the CIS, with 5 MHz intervals between them. Devices using 802.11b/g use 20 MHz channels. Of the 13 channels, 5 are overlapping. To avoid mutual interference between channels, it is necessary that their bands are separated from each other by 25 MHz. That is, only three channels on the 20 MHz band will be non-overlapping: 1, 6 и 11.

What's new in Wi-Fi 6 and how is this standard better than the previous one?

1. Connection speed.
2. Stability of connection when a large number of devices are connected.
3. Working in places with many neighboring networks (where there is a lot of noise).
4. Power efficiency.

Speed in Wi-Fi networks 6

Of course, everyone is primarily interested in connection speed. Wi-Fi 6 offers wireless connectivity at speeds of up to 11 Gbps. But you have to understand that the actual connection speed will be much lower. Of course, the speed increase compared to 802.11ac will be noticeable (almost twice as much). But there is another important point here – the connection speed according to your ISP's tariff. If your ISP's data rate is up to 100Mbps then 802.11ac is more than sufficient. If up to 1 Gbps, then switching to Wi-Fi 6 can of course increase the actual connection speed, since you can hardly squeeze that gigabit out of your wireless network using equipment that works on 802.11ac.

The speed has been increased by changing the information encoding algorithm. Whereas the previous standard used 8-bit information coding the new standard uses 10-bit information coding.

The important point is that 802.11ax can operate in the 2.4 GHz and 5 GHz bands.

Improved performance when connecting a large number of devices

The more devices are connected to the router and the more they use the connection, the lower the speed and stability of the connection. In Wi-Fi 6, this situation has greatly improved. Routers with support for older Wi-Fi standards can simultaneously exchange data with a maximum of several devices. Thanks to OFDMA, which appeared in Wi-Fi 6, it became possible to conduct a parallel exchange of data with a large number of devices. Shorter packets are transmitted, but to a greater number of devices. Graphics from the TP-Link website:

Answers to popular questions about 802.11ax Wi-Fi

I'll answer a few popular questions. If you have other questions on this topic, ask them in the comments. I'll extend the article by answering your questions.

Will my Wi-Fi coverage increase after upgrading to 802.11ax?

No, the network coverage (range) will not increase. It works on the same 2.4GHz and 5GHz bands. The range depends more on the power of the transmitter, which is installed in the router. And also on the antennas. In general, the power of all routers is about the same, because it is limited by the laws of a certain country.

Should I buy a Wi-Fi 6 router in 2020?

In an article with recommendations for choosing a router in 2020, I didn't recommend buying these routers just yet. Why? The standard is very new. There is information online that the Wi-Fi 6 standard is scheduled for final approval in mid-2020. The routers that are already on the market may turn out to be "raw". I would wait until early 2021 and then look at what options are on the market and what you can buy. And the prices for this equipment should go down a bit.

But if you really want to and you have a device with 802.11ax support, then buy it.

Is the router with Wi-Fi 6 compatible with older devices?

Yes, fully backward compatible. With the new router, which supports the 802.11ax standard, you can even connect your old device with 802.11g support.

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Useful and interesting

Router ac, it is necessary for the stable operation of VR technology ax. If you connect an ax amplifier to an ac router will the amplifier broadcast ax(wi-fi 6)

Challenges with 802.11ac

Some analysts and consumers have been skeptical of the benefits 802.11ac brings. Many consumers did not automatically upgrade their home networks from 802.11g to 802.11n, for example, as the older standard generally met basic needs.

To enjoy the performance benefits and full functionality of 802.11ac, devices on both ends of the connection must support the new standard. While 802.11ac routers came into the market fairly quickly, 802.11ac-capable chips have taken much longer to find their way into smartphones and laptops.

An 802.11ac router can have anywhere between 2-8 antennas. Generally speaking, the more antennas a router has, the faster the signal.

While the Xbox 360 console comes with a networking card built-in, the wireless networking adapter also lets you connect to a home network. If your wireless access point is far from your console, the adapter can help improve signal strength and bandwidth.

A distribution system. It lets a wireless network expand across multiple access points. It also preserves MAC addresses between access points.

History of 802.11ac

The technical development of 802.11ac began in 2011. While the standard was finalized in late 2013 and officially approved January 7, 2014, consumer products based on earlier drafts of the standard came before that.

802.11ac specifications

To be competitive in the industry and to support increasingly common applications, such as streaming video, that require high-performance networks, 802.11ac was designed to perform at the Gigabit Ethernet level.

Indeed, 802.11ac offers theoretical data rates of up to 1 Gbps. This is achieved through a combination of wireless signal enhancements, specifically:

802.11ac operates in the 5 GHz signal band, unlike most previous generations of Wi-Fi, which used 2.4 GHz channels. The developers of 802.11ac made this choice for two reasons:

1. To avoid the wireless interference problems common to 2.4 GHz, since many other types of consumer gadgets use the same frequencies, and
2. To realize wider channels than the 2.4 GHz space allows

To ensure backward compatibility with older Wi-Fi products, 802.11ac wireless network routers also include separate support for the 2.4 GHz 802.11n-style protocol.

Another new 802.11ac feature, called beam shapingis designed to improve the reliability of Wi-Fi connections in more crowded areas. Beam shaping technology allows Wi-Fi radios to direct their signals in the direction of the receiving antennas, rather than spreading the signal 180 or 360 degrees as standard radios do.

Beam shaping is one item on the list of features designated by 802.11ac as optional, along with dual-width channels (160 MHz instead of 80 MHz) and some other more obscure features.

Problems with 802.11ac

Some analysts and consumers are skeptical about the real benefits 802.11ac offers. For example, many consumers have not upgraded their home networks from 802.11g to 802.11n because the older standard usually met basic needs.

To take advantage of the performance and full functionality of 802.11ac, devices at both ends of the connection must support the new standard. While 802.11ac routers hit the market fairly quickly, 802.11ac chips took much longer to find their way into smartphones and laptops.

What 802.11ac Wi-Fi is, and how much faster it is compared to 802.11n

If you want better Wi-Fi network performance, you need to use the 802.11ac standard. 802.11ac Wi-Fi is an upgrade to 802.11n (which your current smartphones and laptops probably work with), offering data speeds from 433 megabits per second to several gigabits per second. To achieve dozens of times faster speeds, 802.11ac operates exclusively in the 5 GHz band, uses 80 MHz or 160 MHz bandwidth, operates in eight spatial streams (MIMO) and employs beamforming technology.

Many years ago, the 802.11n standard introduced some interesting technologies that resulted in significantly faster data rates than 802.11b and g. 802.11ac does the same with respect to 802.11n. 802.11n has four spatial streams (4×4 MIMO) and a channel width of 40 MHz, while 802.11ac can use eight spatial streams and has 80 MHz channels that can be combined into 160 MHz channels. Even if everything else were to stay the same (which it isn't), this means that 802.11ac has 8×160 MHz bandwidth versus 4×40 MHz – a huge difference that allows much more data to be transmitted. To increase throughput even higher, 802.11ac also introduces 256-QAM modulation (compared to 64-QAM in 802.11n), which compresses 256 different signals on the same frequency by shifting their phases. This theoretically increases the spectral efficiency of 802.11ac by a factor of four compared to 802.11n. Spectral efficiency is a measure of how well a given wireless protocol or multiplexing method uses the available channel width. In the 5 GHz band, where channels are wide enough (over 20 MHz), spectral efficiency is not as important. On the other hand, in the cellular bands, channels are often only 5 MHz wide, where spectral efficiency is very important.

802.11ac Wi-Fi band

In theory, at 5 GHz with beamforming, 802.11ac should have the same or better range than 802.11n (without beamforming). The 5 GHz frequency does not have the same range as 2.4 GHz (802.11b/g/n) due to less penetration. This compromise has to be made: in the congested 2.4 GHz band, there is not enough spectral bandwidth to provide 802.11ac speeds of several gigabits. If the router is in an ideal position or if you have multiple routers, it doesn't matter. The more important factor will be the transmit power of the devices and the quality of their antennas, as well as their support for MIMO technology.

Finally, the big question: how fast is 802.11ac Wi-Fi? As always, there are two answers: the theoretical maximum speed that can be achieved in the lab and the practical maximum speed for the real world, surrounded by many signal attenuating obstacles. The theoretical maximum speed of 802.11ac is eight 160 MHz 256-QAM channels, each capable of delivering 866.7 Mbit/s – a total of 6933 Mbit/s (7 Gbit/s). That's a data rate of 900 megabytes per second – faster than the SATA 3 standard. In the real world, you probably won't get more than two or three channels at 160 MHz, thanks to channel splitting, so the maximum speed will be somewhere between 1.7 Gbps and 2.5 Gbps. Compare that to the maximum theoretical speed of 802.11n, which is 600 Mbps. In a test by AnandTech portal of the year, the WD MyNet AC1300 802.11ac Wi-Fi router (up to three streams) was paired with 802.11ac devices supporting either one or two streams. The highest data transfer rate was achieved in a laptop with an Intel 7260 802.11ac wireless adapter, which uses two streams to reach 364 Mbps over a distance of 1.5 meters. At 6m and over the wall, the same laptop was also the fastest, at 140 Mbps. The maximum speed for the Intel 7260 is 867 Mbps (2×433 Mbps) according to the specs. In situations where you need maximum wireless performance and reliability, 802.11ac is an extremely attractive option. Instead of cluttering your living room with Ethernet cables, 802.11ac now has enough bandwidth to wirelessly transmit the highest resolution content to your computer or TV. For all but the most demanding uses, 802.11ac is a very viable alternative to Ethernet.

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