IT support people and system administrators have another sophisticated technology in their hands to captivate user interest. But why is it so complicated? If the following is boring to read, give this text to your IT manager, but I still recommend that you read it, because I have been dedicated to this topic for 20 years and have also attended a seminar at TUT and really know the topic of wi-fi on many levels
Wifi is a wireless communication technology that operates on a free frequency, and unfortunately a number of other devices can also operate on these frequencies. In such an environment, there are many sources of interference, bluetooth, wi-fi hotspots operating in mobile phones, AP-s interfering with neighbors, motion sensors, and in a network with many base stations, they will interfere with each other.
To improve free frequency collaboration, standards have been developed to improve coexistence, trying to select optimal parameters and frequencies. However, one of the biggest sources of wifi interference today is the wifi network itself. For example, here is the network in Tallinn, where there were 30 base stations operating on the 2.4 GHz frequency. This network virtually came to a standstill when the number of users exceeded a critical few hundred, making only 6 users on average per base station. We measured this network from the air with a test device for a whole week and were convinced that nothing could be achieved by changing wifi settings. It is often the case that the customer buys an expensive network and everything is fine when there are few users, the problem only arises later when the load increases. The customer is then usually told that you have a problem, we cannot be held responsible for it. Moreover, an inspection is performed and all rooms are inspected by measuring the signal strength. In today's high-density network, such network testing is complete customer and self-deception, but it is still done en masse. The key is to model and design the network so that it works under the desired load, as in the city center, for example, Forum, Viru, Radisson, Swissotell hotels.
The problem is that the 2.4 GHz frequency can accommodate two or three independent access points, and unfortunately the same rules apply to the higher 5 GHz frequency band, because there are higher speeds and channels wider, fortunately 5 GHz has a lower coverage and the problem is a bit simpler but expectations are bigger.
How does a wi-fi network behave in the event of such interference? The user usually sees this as a drop in speed and quite noticeably! Technological reasons are an increase in the level of interference, which forces customers to reduce the transmission speed, or simply a busy situation where the sender is waiting in queue with neighbors. This is called a collision avoidance algorithm, which is mandatory for every wifi device.
Let's take a look at the latest wi-fi 6 802.11ax Ruckus ZoneFlex R650 BeamFlex + access point antenna diagrams. Black shows the direction chart of the antenna tuned to the specific customer in the horizontal and vertical directions. The vertical diagrams are very narrow here, so it is important to choose the right AP installation position in different environments.
All of this is reminiscent of a jungle in the dark of night, where you are completely vulnerable and need very insidious solutions to survive at the end of the day. Reducing the transmit power doesn't really help (client devices don't do this in sync) and mostly only reduces speeds nor doesn't help changing frequencies which are just all busy, and constant change can create chain reaction here. Increasing the density of access points, in any room (unless the walls are completely shielded to radio waves), will certainly not help, as the device will interfere even more.
What's the solution?
Here, the capability of the system administrator does not help to change one or the other parameter in the user interface, this train is gone 5 years ago. To create a network, analysis, modeling, radio-correct implementation and intelligent interference prevention techniques must be used.
R710 802.11 Wave 2 4x4:4 MU-MIMO BeamFlex+
This solution allows a multiple-AP-network to improve the signal path efficiency by an average of 10 times or more (the radio numbers are 10-15 dB accordingly), then with conventional equipment you should reduce the power and coverage by four times and also install significantly more base stations. In real life, we have replaced quite a lot of competitors' equipment, for example, there are three times less equipment in warehouses and half as much in a typical office building.
How does it work? The Ruckus base station (access point, AP) supports all of the standard solutions and can work with 150 simultaneous clients (specs 500) - the antenna uses the expert system, now called artificial intelligence, to select the most optimal antenna direction and polarization for each client at any given time. APs have 500-1500 different such combinations. Ruckus has registered hundreds of patents for such solutions.
Coverage and speeds are higher and the system is more stable than a conventional solution, because the position of the client device in the hand or in the room does not affect the coverage conditions that much with Ruckus. In this situation, the base station is able to continuously adjust its antenna system.
The maximum transmission power is allowed on the free frequency, but with a conventional antenna the maximum power cannot be generated due to static direction to all points of the room, but here BeamFlex + is a good helper for maximum energy exactly where it is needed and as few neighbors as possible.
The salesman immediately says here that we now have Beamforming technology in the 802.11ac standard, yes it is also used by Ruckus, but the technology is essentially the creation of an interference pattern when combining a signal sent to several omni emitters. These images are very 'noisy' indoors and also cut off the use of high-speed MIMO technology. Here's how conventional 801.11ac beamforming works.
The reception is hypersensitive and always works in the correct polarization, all this allows the tablet to be used at 5 GHz in a test performed in a Tondi area in Tallinn at a distance of 400 m outdoors. This solution is ideal for covering large outdoor warehouses and logistics areas and also works in Muuga Port container terminal, for example.
Base stations no longer interfere with each other as much, and therefore the maximum number of users and throughput are even 10 times higher in high load conditions. This is especially true in large networks and very high-density events with a thousand users in one open space. And often it's the only way to get to work today the older 2.4 GHz technology, which has a lot of interference.
The average electricity consumption is significantly reduced, because the energy is not emitted in all directions in the room and the savings are usually in the range of 7-8W.
It seems like a trivial number, but if you have 250 base stations on the site and each of them saves 5W, it means 1.25 KW and thus 1.25 KW x 24 h x 356 p = 10950 KWh per year. This difference is due to the antenna technology and the optimal electronics design. In addition, one third less base stations are needed, from which it can be calculated that the remaining 75 3x3: 3 MIMO conventional base stations would consume another 18W 1.35 KW x 24 h x 356 p = 11826 Kwh. These examples are given in the base of the University of Tartu Clinics. Thus, the total savings are 20,000 KW / h. With today's rising electricity costs, this means savings of 10,000eur in five years.
Behind impenetrable obstacles, the wave can propagate through diffraction or reflections, both of which have significant signal losses and depend very much on the layout of the room. For example, a simple demo is when you go inside a metal van situating about 200m away from AP, communication is not interrupted, as is the case with conventional Wi-Fi technology. The first test was done at a distance of 250m and we wondered how the spread could penetrate so high quality in the interior of the car, even behind the door of the backside, where the tin body obscured any visibility, there was still a spread of 50%.
It often takes the intelligence of a smart antenna to use the right mirror surface, signal polarization and direction at any given time, so as not to create dozens of different reflections, or multi-path fixtures, in an already difficult situation.
Our own tests show that there is a spread from the yard to the interior, as well as going to the other side of 9-storey house, etc. However, the standard solution generates a very large number of reflected signals that the receiver no longer understands. A similar problem is, for example, in a large warehouse full of car parts, where all the shelves have pipes, car tires, metal parts and everything else changes every day. It has been very easy to build such a network with Ruckus BeamFlex.
Wi-Fi base stations should be located where they can see as many customers as possible. Unfortunately, many sources of interference and other base stations can also be seen in this case. In a conventional solution, such a base station constantly detects air traffic in the air and waits most of the time for the air to release, and the speed drops very low due to these waits.
It is almost impossible to find a moment free of disturbance in the air to send your package. Many IT people are unaware that a wi-fi transmitter must then consider any transmitter operating in the same frequency band and channel and be polite in their regard. CSMA/CA is a simplified name for such an algorithm.
This is not about signal strength, but about optimizing complex signal transmission systems that take advantage of spatial reflection conditions, commonly known as MIMO (Multiple Input Multiple Output).
Today's Wi-Fi standards achieve their high speed by sending multiple signals in space at the same frequency simultaneously. The solution seems completely free of common sense at first, but the following explains the technique in terms of ordinary life.
In ordinary language, this is very easy to explain through the example of your two ears - you can understand quite well where the signals are coming from, and even three-dimensionally due to the diffractive shape of the ears. However, if you replace your ears with two isotropic microphones that detect signals in the same way from all directions (a standard Wi-Fi solution is similar to this), you won't understand much of what's going on nearby.) It would be even harder to listen to something in
You with your two ear understand clearly whether the signal comes from the front or from the right, etc.
In the case of MIMO, it is necessary to separate such signals from the air, first to send them optimally to the air and then to receive them. BeamFlex + is fully compatible with MIMO and works with four spatial data channels at the same time. In ordinary language, this means that 130Mb speeds can be 300Mbps and 1.3Gbps with an 11ac standard device, respectively.
However, conventional technology is in trouble here on several levels. Firstly, the signal cannot be received and sent to the room and the customer's location with optimal resolution, therefore MIMO speeds often only work within the same room. The situation becomes even more difficult when Beamforming is used, in which case MIMO must be switched off and the same antenna must be used for beamforming, so the speed drops twice.
The latest 802.11ac Wave 2 standard defines the MU-MIMO protocol, which allows customers to be divided into different groups and assigned different channels in the same frequency in the room. Here, for the sake of clarity (to compare the benefits of BeamFlex +), it is good to bring an analog to light propagation. For example, if there are two round incandescent bulbs in the hallway and you are in a room and need to figure out which bulb the light is coming from, it is almost impossible if these bulbs are still 20 cm apart. However, if both bulbs are fitted with a reflector and they send signals in completely different directions and in different polarizations (you can see it with a special polaroid filter, for example), it is quite possible to guess which beam is, we don't really have to figure out which is either, but just be able to distinguish them. In this way, the two mobile phones in the room described in this room will be able to choose an independent communication channel. Here we get much larger numbers of simultaneous users with Ruckus BeamFlex + technology. This would be especially important in schools where equipment does not move significantly during classes or in offices. We hope that in the future we will see 250-300 numbers on the devices instead of 150 simultaneous users.wp-art-of-rf-engineering
The system is complex and based on complex mathematics, most wifi manufacturers do not have any radio technical expertise. Simply purchase a ready-made IP (Intellectual Propery) and integrate it into the product. Although different administrations and communication protocols are dealt with, the idea of the radio part has been left very simplistic and similar to analogue radio technology. However, the simplistic chip manufacturer's solution is suitable for the widest possible user base. Thus, the solution of most large wifi manufacturers is almost non-existent in terms of new radio technology. The same problem is even more serious on client devices, where space is usually scarce and designers are demanding metal enclosures and increasingly thinner enclosures. Fortunately, however, there are a few exceptions and the forward thinking has not yet disappeared from the world.
Indeed, BeamFlex and Beamforming together give a great result, because we can create a large area to where the signal is not beamed, which means that the neighbors can deliver calmly there and we do not have to wait for them at any time when sending a packet.
Ehk signaalitee suunamine ? BeamFlex+ ja Beamforming on kaks täiesti eri asja, esimene on kõrgsageduslik antennitehnika ja teine puhtalt signaaliöötluse tasandil (vahesagedus) toimiv eri faasis signaalide saatmise tehnika. Kuigi need kaks tehnikat teinetest ei välista ja peavad töötama Ruckus zoneflex tugijaamdes üheaegselt, on Beamformingust üsna vähe kasu just suurtes võrkudes ja küllaltki ilus on see süsteem kodulahenduses või väikekontoris ühe tugijaamaga. Seletused on siin lihtsad
Beamformingu käivitamine ei luba kasutada MIMOt ja kiirus väheneb koheselt kordades, samas on seda beamformingut just vaja seal levi äärealal, kus kiirus niigi väike on.
Beamforming does not work with 802.11n and older standards, so in remote areas where 802.11ac wifi no longer works and the speed is taken down to the old standard therefore Beamforming loses there all efficiency.
Beamforming does not reduce interference and does not actually direct signals in the air, the technique creates an interference pattern that is symmetrical in geometry, and signals propagate from multiple antennas to all points in space. Thus, in order to create a better signal in one place (3dB or twice for two antennas), many other parts of the room also have a higher signal strength.
Beamforming can be started when the customer has made a measurement based on the sounding algorithm, so the efficiency largely depends on the customer's implementation and also on mobility.
In conclusion, it is simply good to know that there is a big difference between the directional antenna and the interference pattern in the air, the pictures can be viewed on the www.3kgroup.ee website. And you just have to consider the environment in which one or the other technique works. People just think that if you turn on this software, the waves from these two wires to the wi-fi device will somehow start to go in a certain direction, as the salesmen have described. But this is not the case, these electromagnetic waves propagate from the two antennas in the same way in space in all directions. If you do not know what the pattern of interference is, it is best to go see what is happening in Tallinn Bay in moderately windy weather, where different waves create higher ridges in one place and lower ones in another.