28.11.2020

Fai fai

And, instead of improving the quality of communication with an increase in the number of points, the opposite effect occurs – its deterioration. Add to this:

uncontrolled mix of user devices with different capabilities, different OS, levels of patches, drivers and types of radio high probability that each user has several devices, the limitations of most modern devices to work in 1×1: 1 HT20 mode interference with LTE-A mobile networks An increased load on the control plane as a result of mass inclusion power saving on end devices floating load on the network, with a difference of hundreds of times, you will understand how complex and multifaceted the task of building is ANOTHER HD WiFi. In no case can this problem be solved by simply increasing the number of points, as they sometimes do – it is written in the datasheet, conditionally, 50 active users per point, divide 80,000/50 and get 1,600 points per stadium. We place the points under the lamps and armchairs, start the network, make sure at the first match that WiFi does not work, and then the options are possible: the integrator / vendor is called to the carpet, a vigorous explanation occurs, the integrator / vendor goes to learn the mat. part and try to correct the situation in real life (it turns out, as a rule, it’s bad), the integrator / vendor is called to the carpet, there is a stormy explanation and swap of the whole project for someone from the Premier League who knows how to do this … The conclusion is simple – only a company that really understands how modern WiFi networks work, which has people who can design, implement and maintain such an infrastructure and, most importantly, which has the tools from which to build such an infrastructure, can successfully make HD WiFi. . Therefore, I’m trying to argue that the presence in the company’s portfolio of such successfully implemented projects (and therefore, such resources and expertise) unambiguously ranks it among the WiFi Premier League. “- These entities are more advanced than us. Why don’t they just come right out and tell us what’s on their minds? -You’re more advanced than a cockroach, have you ever tried explaining yourself to one of them? ”The Mothman Prophecies

Let’s talk now about how and with what technologies HD WiFi can and should be implemented. As mentioned above, the main “scourge” of HD WiFi is interference and the total network capacity determines the number of radio channels, not the number of access points. Interference can be divided into two types – Adjacent Channel Interference (ACI) and Co-Channel Interference (CCI). ACI is when two channels intersect at the spectral boundary and the energy emitted outside the range increases the level of radio noise in adjacent channels and, as a result, the number of errors, which is especially true in the 2.4 GHz band, where there are only 3 disjoint channels. This type of interference, as a rule , does not have a significant effect in conventional corporate WiFi networks, as the average distance between points in such networks is about 20 meters, which, with standard losses of 80dB for 5GHz, sufficient isolation is provided and Clear Channel Assessment (CCA) mechanisms do not see the 802.11 frame, does not detect collision and does not mark a free channel as busy. A completely different story is obtained when building HD WiFi. Here the points are located so close to each other that the ACI is determined by CCA mechanisms as a collision and neighboring channels turn, in fact, into one collision domain with all the consequences. To make it clearer, let’s look at a simple example of what happens in such a case.

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