Short comparison 11n vs 11ac vs 11ad. And what services will we see in the future
Earlier, at the dawn of the commercial development of the 802.11 standards, wireless networks were slower than wired when considering bandwidth. With the introduction of the 802.11n standard, we have already obtained quite similar speeds with conventional mass wired connections. Now the main development of stanadarts is moving towards 802.11ac and 802.11ad, which will allow getting speeds at the level of several gigabits per second over a wireless network.
A brief comparison of these standards is presented in the table.
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This technology is widely known, so in this article we will not elaborate on technical details.
Possible services here often seem clear and well-known, but in fact there are a lot of options in the world of very interesting services based on 802.11n technology. The practical implementation of unusual services on 11n networks can be found in the next article , especially in the second half.
The 802.11ac standard only works in the 5GHz spectrum. Backward compatibility with 802.11n (5GHz) and 802.11a devices will be provided. In this case, it is expected a significant increase in not only the bandwidth, but also coverage.
Broadcom, who was the first to release a 802.11ac chip, believes that the maximum speed will be up to 3.47Gbps at short distances. For cases of basic 802.11ac implementation, for example, on smartphones and other basic user devices in the Wi-Fi part (one antenna and radio module, 80MHz channel, one spatial stream), we can expect speeds of up to 433Mbps at distances of up to 10m. This is several times more compared to 802.11n in the same conditions. Broadcom also claims that the released SoC 802.11ac chip is three times faster and six times more energy efficient than 11n solutions. The chip supports both 2.4GHz and 5GHz, so it is backward compatible with current platforms (at 2.4GHz only 11n is supported).
Netgear concludes that devices with an 802.11ac chip and one radio module (one antenna) will achieve similar speeds with identical power consumption with the current fastest solutions for 802.11n (3 radio modules / 3 antennas, etc.). This means that a typical tablet computer with one radio module 11n and supporting up to 150Mbps, with a module 11ac in a similar design, will be able to achieve maximum speeds of 450Mbps.
802.11ac supports up to 8 antennas and radio modules (11n to 4), so the 8x8 MIMO level is theoretically achievable here. At the same time, it is possible to work with modulation up to 256QAM and transmit data through 8 spatial streams. An important innovation is the technology MU-MIMO (Multiple User). This is actually a spatial radio switch that allows you to simultaneously transmit and receive data from multiple users on the same frequency channel.
Broadcom released the first version of the 802.11ac chip (SoC / System on Chip) in mid-February 2012. Atheros’s closest competitor (owned by Qualcomm since 2011) is due to release its version in the second quarter of 2012.
According to ABI Research, 802.11ac will become the dominant standard by 2014. In-Stat also predicts a rapid growth of 11ac with deliveries of about 1 billion devices with 11ac chips until 2015. Moreover, by 2015 already 100% of Access Points will be supplied with 802.11ac chips.
In terms of 802.11ac services, on the one hand, it focuses on a much more comprehensive replacement of wired access at high speeds than 802.11n. On the other hand, of course, there is a goal in effectively supporting multimedia services around high-resolution video streaming.
The other side of the coin is the availability of frequency channels in the 5GHz spectrum, which varies greatly from country to country, and in the Russian Federation it is, for example, only 100MHz (5150-5250MHz), details are here . Therefore, until our regulator deeply thinks about the need to release part of the 5GHz spectrum for Wi-Fi tasks, as has been done in many countries, this attractive technology will remain a beautiful fairy tale in our realities.
The standard will operate in the 60GHz spectrum, which is not licensed in most countries. There is much more free band available here than in the overloaded 2.4GHz and already loaded 5GHz spectrum.
In terms of services, this standard focuses on high-definition (HD) video support. Also, the emergence of “wireless docking” services is expected here, when all devices are a computer, monitor, projector, etc. have wireless data exchange. Thus, this is a great way to assemble a number of different devices that require high bandwidth to connect, and completely remove data cables and video cables from the solution, including removing HDMI cables for HD video. Used ultra-high frequency leads to the fact that the signals are quite narrowly targeted. There are also many problems due to the intense absorption of signals as they pass through obstacles, so the main expected usage scenario is the interaction of devices within the room.
Also, 802.11ad should be the basis for technology in the Wi-Fi Display, which is developed by the Wi-Fi Alliance. Intel's Wi-Di is now the predecessor, although Wi-Di is far from the characteristics of 11ad, and specialized hardware chips from Intel are required.
802.11ad is expected to be compatible with the WiGig standard.
A brief comparison of these standards is presented in the table.
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802.11n
This technology is widely known, so in this article we will not elaborate on technical details.
Possible services here often seem clear and well-known, but in fact there are a lot of options in the world of very interesting services based on 802.11n technology. The practical implementation of unusual services on 11n networks can be found in the next article , especially in the second half.
802.11ac
The 802.11ac standard only works in the 5GHz spectrum. Backward compatibility with 802.11n (5GHz) and 802.11a devices will be provided. In this case, it is expected a significant increase in not only the bandwidth, but also coverage.
Broadcom, who was the first to release a 802.11ac chip, believes that the maximum speed will be up to 3.47Gbps at short distances. For cases of basic 802.11ac implementation, for example, on smartphones and other basic user devices in the Wi-Fi part (one antenna and radio module, 80MHz channel, one spatial stream), we can expect speeds of up to 433Mbps at distances of up to 10m. This is several times more compared to 802.11n in the same conditions. Broadcom also claims that the released SoC 802.11ac chip is three times faster and six times more energy efficient than 11n solutions. The chip supports both 2.4GHz and 5GHz, so it is backward compatible with current platforms (at 2.4GHz only 11n is supported).
Netgear concludes that devices with an 802.11ac chip and one radio module (one antenna) will achieve similar speeds with identical power consumption with the current fastest solutions for 802.11n (3 radio modules / 3 antennas, etc.). This means that a typical tablet computer with one radio module 11n and supporting up to 150Mbps, with a module 11ac in a similar design, will be able to achieve maximum speeds of 450Mbps.
802.11ac supports up to 8 antennas and radio modules (11n to 4), so the 8x8 MIMO level is theoretically achievable here. At the same time, it is possible to work with modulation up to 256QAM and transmit data through 8 spatial streams. An important innovation is the technology MU-MIMO (Multiple User). This is actually a spatial radio switch that allows you to simultaneously transmit and receive data from multiple users on the same frequency channel.
Broadcom released the first version of the 802.11ac chip (SoC / System on Chip) in mid-February 2012. Atheros’s closest competitor (owned by Qualcomm since 2011) is due to release its version in the second quarter of 2012.
According to ABI Research, 802.11ac will become the dominant standard by 2014. In-Stat also predicts a rapid growth of 11ac with deliveries of about 1 billion devices with 11ac chips until 2015. Moreover, by 2015 already 100% of Access Points will be supplied with 802.11ac chips.
In terms of 802.11ac services, on the one hand, it focuses on a much more comprehensive replacement of wired access at high speeds than 802.11n. On the other hand, of course, there is a goal in effectively supporting multimedia services around high-resolution video streaming.
The other side of the coin is the availability of frequency channels in the 5GHz spectrum, which varies greatly from country to country, and in the Russian Federation it is, for example, only 100MHz (5150-5250MHz), details are here . Therefore, until our regulator deeply thinks about the need to release part of the 5GHz spectrum for Wi-Fi tasks, as has been done in many countries, this attractive technology will remain a beautiful fairy tale in our realities.
802.11ad
The standard will operate in the 60GHz spectrum, which is not licensed in most countries. There is much more free band available here than in the overloaded 2.4GHz and already loaded 5GHz spectrum.
In terms of services, this standard focuses on high-definition (HD) video support. Also, the emergence of “wireless docking” services is expected here, when all devices are a computer, monitor, projector, etc. have wireless data exchange. Thus, this is a great way to assemble a number of different devices that require high bandwidth to connect, and completely remove data cables and video cables from the solution, including removing HDMI cables for HD video. Used ultra-high frequency leads to the fact that the signals are quite narrowly targeted. There are also many problems due to the intense absorption of signals as they pass through obstacles, so the main expected usage scenario is the interaction of devices within the room.
Also, 802.11ad should be the basis for technology in the Wi-Fi Display, which is developed by the Wi-Fi Alliance. Intel's Wi-Di is now the predecessor, although Wi-Di is far from the characteristics of 11ad, and specialized hardware chips from Intel are required.
802.11ad is expected to be compatible with the WiGig standard.
Source: https://habr.com/ru/post/139765/
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