Gigabit Wi-Fi in Russia
The recent announcement of the allocation of additional frequencies of 5650-5850 MHz for intra-office use of Wi-Fi networks has pleased us with new opportunities that have opened up to users of wireless networks.
Almost a year ago, the Order of the Ministry of Communications and Mass Media No. 129 of April 22, 2015 removed the restriction for 802.11ac equipment to use 80 and 160 MHz channels, however, the spectrum allocated for these solutions did not allow obtaining maximum speeds.
Pending publication of the decisions of the SCRF, we will examine this issue.
The picture above reflects the situation in the 5GHz band in the United States. What is in Russia?
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In accordance with the standard Wi-Fi 802.11ac uses a 5GHz band. In Russia, since November 2014 (GKRCh Decision 14-29-01 dated 11/20/2014), the range 5150-5350 MHz or 8 channels of 20 MHz (channels 36-64) is defined for intra-office use by Wi-Fi technology. The range 5650-5825 MHz (channels 132-161) is open to aircraft that are in flight at a height of at least 3000 m.
The new decision of the GKRCH doubles the range available for Wi-Fi indoors.
At the same time, for the ranges 5 150–5 350 MHz and 5 650–5 850 MHz (channels 36–64, 132–155), the twice-admissible radiation power was announced: now it is 10 mW at 1 MHz. For wide channels of 80 and 160 MHz, the existing limit of 5 mW / MHz meant a rather low EIRP on access points.
But also for 802.11n networks using channels of 20 and 40 MHz, the additional power is an improvement for industrial and warehouse premises with high ceilings, and metal structures that require narrowly-directional antennas, which give a large signal focus and do not fit into the EIMM limit of 200 mW.
802.11ac allows the use of channels 20, 40, 80 and 160 MHz. At the same time, channels at 20, 40, and 80 MHz use a continuous band, and for a channel at 160 MHz, they can add up to 2 at 80 MHz. Transmission rates vary in proportion to the channel width. At 200 MHz of the previously available spectrum, only one channel with a width of 160 MHz fits, which makes it impossible to create a solid Gigabit Wi-Fi coverage with maximum performance. A good practice is to use 3 frequency channels to create a continuous coverage. Neighboring points should be tuned to different channels in order not to create co-channel interference. With a high level of interference, the signal-to-noise ratio decreases, and it is the main factor when choosing the connection speed of the access point and client device.
In the current situation, 8/4/2/1 channel at 20/40/80/160 MHz is available for creating a Gigabit Wi-Fi network indoors in Russia. For comparison, 22/10/5/1 channels at 20/40/80/160 MHz are available in 5 GHz in the USA. Work is underway to increase the available spectrum to 34/16/8/3 channels.
After the publication of the new Decision of the State Committee on Radio Frequencies, we will have 17/8/4/2 channels at 20/40/80 / 160MHz. Now there are interesting options for radio planning of the 802.11ac network.
Available 802.11c transmission rates compared to 802.11n, depending on the channel width, the number of spatial streams supported by the client, and the connection speeds are as follows:
In accordance with the standard, 802.11ac access points support up to 8 spatial streams (PPs). At the same time, in practice, client devices are limited to 3 spatial streams. Additional spatial streams at the access point exist for implementing MU-MIMO, a key 802.11ac innovation. This revolutionary change has shaken the principle, which has unshakably existed for many years, defining communication with one client per unit of time. The ability to simultaneously connect to multiple clients (up to 4x in theory) allows you to immediately increase the total transfer speed in a Wi-Fi network. This method is difficult to implement, does not always work, because devices should be located “conveniently” for the access point, but its implementation rewards a significant increase in throughput.
Imagine the maximum scenario in which the point and clients use the channel at 160 MHz, the radio environment is ideal, the clients are within 2-3 meters from the access point for using 256-QAM, they are conveniently located for MU-MIMO. To maximize total bandwidth, one of the clients supports 4 spatial streams (for example, this is an access point). In such a combination, theoretically, we can get replicated 6.9GB / s:
- 1 client with 4PP - 3.47Gb / s
- 1 client with 2PP - 1.73Gb / s
- 2 clients with 1PP - 867Mb / s each
Of course, this scenario is unrealizable in life. In addition to the above factors, we will face the fact that client devices do not support 160 MHz, they choose a reduced number of spatial streams in battery mode, there are interference on the radio, and clients with previous standards are connected. In addition, the functionality of MU-MIMO gives an advantage only when transmitting from an access point to devices, and from devices to a point, the connection goes one by one, as before. The created groups of MU-MIMO devices will share the airtime between themselves, so it’s impossible to get all the bandwidth for one group if there is at least one more client in the network.
The addition method in this case is only suitable for obtaining a beautiful inscription on the box, decorated with the vendor logo.
Due to the absence of client devices with support for the 160 MHz band, the most frequent scenario before their appearance will be the use of 80 MHz channels. The selected spectrum allows us to use as many as 4 channels at 80 MHz. Why the fourth?
The new Cisco Aironet 2800 and 3800 Series access points announced in February for Cisco Live in Berlin have interesting features that allow you to utilize “redundant” channels to further increase network bandwidth.
The Flexible Radio Assignment (FRA) functionality or the Flexible radio assignment will make the wireless network even more productive. A Wi-Fi network on such equipment can decide how to use the existing 2 radios - normally at 2.4 and 5 GHz, or both of the 5 GHz radios to increase network capacity, finding that all devices on the network support both bands. In such a scenario, the network achieves peak performance by transmitting up to 5.2 Gb / s with 160 MHz channels. The network may also decide that in the current download its capacity is redundant and it must switch from the access points to the air listening mode to ensure a high level of security. But at that moment, when the load increases, this access point can again be transferred to the customer service mode.
Another interesting way to use the benefits of Flexible Radio Assignment is to group clients on one of five-gigahertz radios based on their distance from the access point. The effect of reducing the overall performance of a wireless network is known when the client is significantly removed from its access point. The signal level from the client becomes low, the transmission goes at minimum speed and requires retransmissions. These operations take up airtime, leaving less time to transfer customer data that is nearby and connected at maximum speeds. By converting one of the radios into a macro cell for connecting remote clients, and the second into a micro cell for connecting those sitting nearby, we give high performance to clients connected at high speeds, while not denying coverage to remote devices. In this embodiment, a new type of roaming appears - inside one access point.
Is the script real? In the educational segment, where young people bring new devices, in an office environment, where knowledge workers mainly use the top-end smartphone line - yes, absolutely.
Do you need such speeds?
In accordance with the latest Visual Networking Index , mobile traffic will increase 10-fold in the period 2015–2020, while the traffic displayed on the Wi-Fi network from mobile devices will increase proportionately. The number of Wi-Fi hotspots in Russia will grow 90 times.
Networks planned without this growth may require modernization in a couple of years.
Access points 2800 and 3800 are the flagship in the Wi-Fi line of Cisco, with maximum performance and functionality. The first commercial shipments of these products are expected in May. In Russia, these access points can be ordered in August 2016.
Materials
- Webinar "Differences 802.11ac and 802.11n"
- 802.11ac: The Fifth Generation of Wi-Fi Technical White Paper
- Decision of the State Committee on Radio Frequencies 14-29-01 dated 11/20/2014
- Order of the Ministry of Communications and Mass Media â„– 129 dated 04.22.2015
- “No Strings Attached Show - Networking Without Strings” podcast with Cisco 2800 and 3800 Series Access Point Managers Brian Levin and Mark Denny
- Cisco Aironet 2800 Series Access Points Data Sheet
- Cisco Aironet 3800 Series Access Points Data Sheet
Almost a year ago, the Order of the Ministry of Communications and Mass Media No. 129 of April 22, 2015 removed the restriction for 802.11ac equipment to use 80 and 160 MHz channels, however, the spectrum allocated for these solutions did not allow obtaining maximum speeds.
Pending publication of the decisions of the SCRF, we will examine this issue.
The picture above reflects the situation in the 5GHz band in the United States. What is in Russia?
')
In accordance with the standard Wi-Fi 802.11ac uses a 5GHz band. In Russia, since November 2014 (GKRCh Decision 14-29-01 dated 11/20/2014), the range 5150-5350 MHz or 8 channels of 20 MHz (channels 36-64) is defined for intra-office use by Wi-Fi technology. The range 5650-5825 MHz (channels 132-161) is open to aircraft that are in flight at a height of at least 3000 m.
The new decision of the GKRCH doubles the range available for Wi-Fi indoors.
At the same time, for the ranges 5 150–5 350 MHz and 5 650–5 850 MHz (channels 36–64, 132–155), the twice-admissible radiation power was announced: now it is 10 mW at 1 MHz. For wide channels of 80 and 160 MHz, the existing limit of 5 mW / MHz meant a rather low EIRP on access points.
But also for 802.11n networks using channels of 20 and 40 MHz, the additional power is an improvement for industrial and warehouse premises with high ceilings, and metal structures that require narrowly-directional antennas, which give a large signal focus and do not fit into the EIMM limit of 200 mW.
802.11ac allows the use of channels 20, 40, 80 and 160 MHz. At the same time, channels at 20, 40, and 80 MHz use a continuous band, and for a channel at 160 MHz, they can add up to 2 at 80 MHz. Transmission rates vary in proportion to the channel width. At 200 MHz of the previously available spectrum, only one channel with a width of 160 MHz fits, which makes it impossible to create a solid Gigabit Wi-Fi coverage with maximum performance. A good practice is to use 3 frequency channels to create a continuous coverage. Neighboring points should be tuned to different channels in order not to create co-channel interference. With a high level of interference, the signal-to-noise ratio decreases, and it is the main factor when choosing the connection speed of the access point and client device.
In the current situation, 8/4/2/1 channel at 20/40/80/160 MHz is available for creating a Gigabit Wi-Fi network indoors in Russia. For comparison, 22/10/5/1 channels at 20/40/80/160 MHz are available in 5 GHz in the USA. Work is underway to increase the available spectrum to 34/16/8/3 channels.
After the publication of the new Decision of the State Committee on Radio Frequencies, we will have 17/8/4/2 channels at 20/40/80 / 160MHz. Now there are interesting options for radio planning of the 802.11ac network.
Available 802.11c transmission rates compared to 802.11n, depending on the channel width, the number of spatial streams supported by the client, and the connection speeds are as follows:
In accordance with the standard, 802.11ac access points support up to 8 spatial streams (PPs). At the same time, in practice, client devices are limited to 3 spatial streams. Additional spatial streams at the access point exist for implementing MU-MIMO, a key 802.11ac innovation. This revolutionary change has shaken the principle, which has unshakably existed for many years, defining communication with one client per unit of time. The ability to simultaneously connect to multiple clients (up to 4x in theory) allows you to immediately increase the total transfer speed in a Wi-Fi network. This method is difficult to implement, does not always work, because devices should be located “conveniently” for the access point, but its implementation rewards a significant increase in throughput.
Imagine the maximum scenario in which the point and clients use the channel at 160 MHz, the radio environment is ideal, the clients are within 2-3 meters from the access point for using 256-QAM, they are conveniently located for MU-MIMO. To maximize total bandwidth, one of the clients supports 4 spatial streams (for example, this is an access point). In such a combination, theoretically, we can get replicated 6.9GB / s:
- 1 client with 4PP - 3.47Gb / s
- 1 client with 2PP - 1.73Gb / s
- 2 clients with 1PP - 867Mb / s each
Of course, this scenario is unrealizable in life. In addition to the above factors, we will face the fact that client devices do not support 160 MHz, they choose a reduced number of spatial streams in battery mode, there are interference on the radio, and clients with previous standards are connected. In addition, the functionality of MU-MIMO gives an advantage only when transmitting from an access point to devices, and from devices to a point, the connection goes one by one, as before. The created groups of MU-MIMO devices will share the airtime between themselves, so it’s impossible to get all the bandwidth for one group if there is at least one more client in the network.
The addition method in this case is only suitable for obtaining a beautiful inscription on the box, decorated with the vendor logo.
Due to the absence of client devices with support for the 160 MHz band, the most frequent scenario before their appearance will be the use of 80 MHz channels. The selected spectrum allows us to use as many as 4 channels at 80 MHz. Why the fourth?
The new Cisco Aironet 2800 and 3800 Series access points announced in February for Cisco Live in Berlin have interesting features that allow you to utilize “redundant” channels to further increase network bandwidth.
The Flexible Radio Assignment (FRA) functionality or the Flexible radio assignment will make the wireless network even more productive. A Wi-Fi network on such equipment can decide how to use the existing 2 radios - normally at 2.4 and 5 GHz, or both of the 5 GHz radios to increase network capacity, finding that all devices on the network support both bands. In such a scenario, the network achieves peak performance by transmitting up to 5.2 Gb / s with 160 MHz channels. The network may also decide that in the current download its capacity is redundant and it must switch from the access points to the air listening mode to ensure a high level of security. But at that moment, when the load increases, this access point can again be transferred to the customer service mode.
Another interesting way to use the benefits of Flexible Radio Assignment is to group clients on one of five-gigahertz radios based on their distance from the access point. The effect of reducing the overall performance of a wireless network is known when the client is significantly removed from its access point. The signal level from the client becomes low, the transmission goes at minimum speed and requires retransmissions. These operations take up airtime, leaving less time to transfer customer data that is nearby and connected at maximum speeds. By converting one of the radios into a macro cell for connecting remote clients, and the second into a micro cell for connecting those sitting nearby, we give high performance to clients connected at high speeds, while not denying coverage to remote devices. In this embodiment, a new type of roaming appears - inside one access point.
Is the script real? In the educational segment, where young people bring new devices, in an office environment, where knowledge workers mainly use the top-end smartphone line - yes, absolutely.
Do you need such speeds?
In accordance with the latest Visual Networking Index , mobile traffic will increase 10-fold in the period 2015–2020, while the traffic displayed on the Wi-Fi network from mobile devices will increase proportionately. The number of Wi-Fi hotspots in Russia will grow 90 times.
Networks planned without this growth may require modernization in a couple of years.
Access points 2800 and 3800 are the flagship in the Wi-Fi line of Cisco, with maximum performance and functionality. The first commercial shipments of these products are expected in May. In Russia, these access points can be ordered in August 2016.
Materials
- Webinar "Differences 802.11ac and 802.11n"
- 802.11ac: The Fifth Generation of Wi-Fi Technical White Paper
- Decision of the State Committee on Radio Frequencies 14-29-01 dated 11/20/2014
- Order of the Ministry of Communications and Mass Media â„– 129 dated 04.22.2015
- “No Strings Attached Show - Networking Without Strings” podcast with Cisco 2800 and 3800 Series Access Point Managers Brian Levin and Mark Denny
- Cisco Aironet 2800 Series Access Points Data Sheet
- Cisco Aironet 3800 Series Access Points Data Sheet
Source: https://habr.com/ru/post/278839/
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