Improving the work of Wi-Fi. Part 3. Location of access points

Usually, when they say that it is possible to improve the quality of work of something, they mean the introduction of any new products, updates, in general, all that is associated with the acquisition of new technology.

However, in the pursuit of technical innovations, such important things as the operating conditions and equipment placement are sometimes missed.

In the articles " Improving the work of Wi-Fi. General principles and useful things "and
“ We are improving the work of Wi-Fi. Part 2. Features of the equipment "we have already raised the question of how to make a Wi-Fi network more efficient.

Below we consider the placement of access points and coverage.

About the examples in this article

Giving advice “for all occasions” is an extremely ungrateful thing. If only because IT is just a display of a business, a display of an organization’s work in a kind of digital representation. And just as there are no two exactly identical enterprises, there are no identical IT systems.

Of course, this simple rule also applies to communication systems.

Therefore, in our examples we consider the simplest option: a small organization
occupies a small room of two rooms. The rooms are separated by a temporary
partition, for example, plasterboard.

Previously, we have considered just such a small room when it came to access points on the ceiling. Now the main discussion will focus on the placement of points on the wall and everything connected with it.

Location of access points in the room

As mentioned above, correct placement plays a big role. A good idea - when choosing a device for wireless communication in advance to get your hands on the floor plan.

In a more detailed analysis, it may turn out that a simple purchasing choice leads to difficulty in installation, operation and safety.

Below are some tips on how to avoid this.

Two points next to different sides of the septum

The option, which due to the ease of installation and the ability to "not bathe" with the mount and the like, may seem at first glance very attractive.

Both access points are located nearby, but on opposite sides of the partition.

Figure 1. Two access points located at different ends of the same partition.

The apparent advantages of this approach:

• in partitions it is more convenient to drill holes in order to hang
  device.
• With this compact layout, it is easier to use the existing infrastructure for communications and power supply. For example, there is a power outlet near. Even if this “luxury” is present only on one side of the partition, a small hole for wires is being drilled, and now the solution for communication and power supply of the second access point is ready.

It would seem that everything is fine, but the trouble is that the materials for light partitions are not a serious obstacle for the radio waves of Wi-Fi.

First of all, we are talking about the 2.4 GHz band, but even 5 GHz can pass through very thin overlaps. It would seem: “That's great!” - but, if we recall the mutual parasitic influence of transmitters on each other, the picture becomes not at all bright.

Partially compensating for such close placement is possible by adjusting the points to different channels (see the article “Improving Wi-Fi performance. General principles and useful things”). This is a good method to reduce mutual influence, but such a life hack is still not a panacea.

Another technique is to reduce the signal intensity. Simply put, the transmitter power is less, therefore, the level of interference to neighboring points will also be less. The trouble is that such a solution often reduces not only the impact on the “neighbors”, but also the quality of communication at remote distances.

Break up the corners!

Reading about all the difficulties that arise when the receiving-transmitting equipment is very close to being placed, a reasonable question arises: is it not easier to simply spread the points to the maximum distant distance?

For example, as shown in Figure 2. In this case, the mutual influence will be minimized. And the transmitters themselves can be tuned for greater power in order to “reach” all remote sections with a signal.

Figure 2. Two access points located at opposite corners.

From the point of view of eliminating interference, such an arrangement would be most preferable.

On one partition farther apart

The placement option in Figure 3 is a kind of compromise between removing points from each other and trying to use a partition made of lightweight materials for ease of fixing points. Of course, somewhat larger than in the first case, the removal of points from each other reduces the mutual influence. In conjunction with the diversity in different channels and power control, this option may be quite working.

Figure 3. Two access points located on the same partition with the maximum
removal.

All this reminds already considered in the article “Improving the performance of Wi-Fi. Part 2. Features of the equipment " example with the ceiling placement of points. Both in this and in this case it is necessary to take into account issues of mutual influence. However, the pie chart of the signal propagation when placed on the ceiling in the center of the room allows you to “reach” the far corners with greater ease.

At the same time, wall placement as in Figure 3 may be the only possible due to certain restrictions, for example, because of the prohibition to drill capital walls and the inability to suspend something on the ceiling. But if there are no such requirements, it is worthwhile to look more closely at the option with the maximum distance (Figure 2) or at the placement of access points on the ceiling.

Street openness

Figure 4 shows a variant that at first glance is similar to the case with the maximum removal in Figure 2. However, there is an important detail: access points are located near the windows.

Figure 4. Access points in opposite corners near windows.

Despite the fact that radio waves pass through the glass worse than through a cardboard office partition, part of the signal will “leak” into the street.

On the one hand, it seems to be good - the employee briefly went out to smoke and still the office Wi-Fi is a little bit, but is caught on the smartphone, and there is access, for example, to corporate chat.

On the other hand, the same signal can be received on devices of unauthorized people.

Portable communication tools, such as a smartphone or tablet, configured to automatically search for available networks, put an additional load on the access point.

Of course, hiding the SSID when searching for a network partially helps in such situations, although the network still remains available for scanning. But is not it easier to move the access point away from the window?

In addition, the potential availability of Wi-Fi signal on the street makes it easier to penetrate the company's network. Of course, knowledge of additional information, for example, SSID is not yet an open door to the corporate network. Still, it is better to avoid disclosing even such seemingly “publicly available” information.

When an attacker knows the name of a network, he can try to get an access key, for example, using social engineering. And then all hope is only for common sense and the observance of safety rules by ordinary workers.

IMPORTANT! Even completely reliable wireless security technologies like WPA2 do not guarantee complete security.

Alas, in some cases, this way of working “to the street” at first may seem
not a bad decision.

For example, if a small cafe has settled in the room and additional tables will be installed outside the window. In this case, it may seem that the placement of the access point near the window solves all questions. Part of the signal will pass to the street and there seems to be access to WI-Fi.

Without addressing the nuances in terms of security and similar details, consider the issue of signal propagation.

Firstly, the glass does not pass WI-Fi radio frequencies very well, especially if we are talking about the 5 GHz band. If grilles are installed on the windows, the signal power will drop even more.

Secondly, the coverage with this placement will be extremely uneven. A table in the immediate vicinity of the window will still receive a stronger signal than standing at a distance. It turns out that cafe visitors are in unequal conditions.

In this case, the main recommendation is to use a more specialized approach to the organization of public networks.

It would be much better to install an external access point for outdoor (street) placement. In this case, you can use all available ranges. It is possible to significantly reduce power, so that the coverage area extends only to the tables.

Figure 5. Using an external access point.

External equipment can be temporarily disabled when its work is not needed, for example, in the colder season. During off-hours, an internal access point may still be needed until employees go home, but there is no need to provide Internet access on the street at this time, so it’s better to turn off the external point immediately after closing for the night. Such measures reduce access to the network for bystanders or intruders.

Council Of the access points for external placement is worth paying attention to the WAC6550 Series . This point has the opportunity for universal placement on the wall or under the ceiling, for example, under a canopy. This point allows you to connect a large number of customers, which is optimal for street cafes in the “hot time”.

Access points WAC6550 Series also allow the use of smart antennas , which makes it possible to increase the capacity of the network without reducing its coverage.

Such a smart antenna selects from the hundreds of available signal patterns the most suitable for communication with the client device at the moment. Adaptation to the external conditions (the choice of the optimal diagram) is performed continuously at intervals of tenths of a second. This ensures high speed and reliability of the wireless network. At the same time, users can move freely with mobile devices without worrying about signal quality. If we talk about the imposition of connections, then it is minimized - each connection uses its own signal directivity pattern, which allows for maximum performance.

Let's summarize

When placing equipment for wireless communication, consider not only installation issues (presence of sockets, ease of mounting), but material properties as an obstacle to the Wi-Fi signal.

The location of the access point next to the window is not a good idea in terms of security. If there is a need to provide “street Internet” - use an access point for outdoor accommodation with its accessibility turned off at night.

All these recommendations seem to be rather simple, one might say primitive, but in many cases their adherence allows improving communication and simplifying the operation and maintenance of a wireless network.