Do not forget this point when choosing wireless LAN in the office

　Work style reforms to realize a flexible work style that is not bound by time or place are attracting attention. For example, a free address office where employees do not have their own desks. Flexible working styles are possible, such as being able to freely use vacant seats and having members gather to work according to the work of the day. At advanced companies, efforts are being made to reduce rent by limiting the number of desks in the office to about 80% of the number of employees. In-office mobiles, in which laptops and tablets are carried to conference rooms, etc., have also become popular. If participants bring their own laptops or tablets, the materials they use can be distributed as digital data, making paperless meetings a reality.

　A wireless LAN environment is essential to enable them. The communication speed of wireless LAN is now at a level that does not make you feel dissatisfied even compared to wired LAN. There is no need to connect cables one by one, so you can choose the layout of the seat. You can work anywhere as long as the radio waves reach.

　However, there are various standards for wireless LAN. Depending on which type of wireless LAN you choose, there will be differences in speed, stability, and usability.

The mainstream is IEEE802.11ac　The latest technology improves speed and stability

　The current mainstream wireless LAN standard is IEEE802.11ac (hereinafter referred to as 11ac). There are other standards such as IEEE802.11a (hereafter, 11a), IEEE802.11b (hereafter, 11b), IEEE802.11g (hereafter, 11g), and IEEE802.11n (hereafter, 11n). ' will be the one. 11a and 11b are from the era when the spread of wireless LAN began, and are hardly used now. 11g has a maximum speed of 54 Mbps, and 11n is 600 Mbps, which is slower than 11ac. As for the frequency band, 11a uses the 5 GHz band, 11b uses the 2.4 GHz band, and 11g and 11n use both.

　The mainstream 11ac uses the 5 GHz band and has a maximum speed of 6.9 Gbps, which is much faster than conventional standards. Details will be explained later, but useful functions such as beamforming and MU-MIMO can also be used. 11ac-compatible access points maintain compatibility with existing standards such as 11g and 11n, so even devices with older standards can be connected if the frequencies match.

　Compared to conventional standards, 11ac has advantages in terms of speed and stability, and it can be said that there is no other option for access points used in offices.

　However, when choosing 11ac, whether or not it supports Wave2 becomes important. Wave2 is the second generation of 11ac, and compared to the first generation Wave1, improvements such as beamforming, MU-MIMO support, and speed increase have been added.

Key points in choosing a wireless LAN access point

So, what points should you pay attention to when choosing a wireless LAN access point? The points are shown below.

Point 1 Should you choose 2.4GHz band or 5GHz band?

As mentioned above, there are two types of wireless LAN standards: the 2.4 GHz band and the 5 GHz band. In fact, this difference greatly affects the stability of the wireless LAN. The 2.4 GHz band is used not only for wireless LAN, but also for Bluetooth, wireless mice, etc. It is also used for home appliances such as microwave ovens and cordless phones. Therefore, radio wave interference is likely to occur.

　Radio waves are particularly strong in microwave ovens. If you have a microwave oven in your office's hot water supply room and someone tries to heat up the food, it can adversely affect your wireless LAN, causing problems such as being unable to connect to the network or slowing down the speed.

On the other hand, 11ac, which uses the 5GHz band, can avoid such radio interference. If stability in the office is important, 11ac using the 5GHz band is excellent.

Point 2 Mixing with previous standards 11n and 11g?

In order to enjoy the benefits of 11ac, both the parent device, the access point, and the child device, must be compatible with 11ac.

　As long as the frequency band matches, the access point maintains compatibility with older standards, so it is possible to connect to older devices. However, the speed and functions will match the old standard, so the speed of 11ac will not be demonstrated. Also, even if the access point and device both support 11ac, the same problem can occur if you connect with 11n or 11g.

It is desirable to avoid mixing with 11n and 11g so that 11ac compatible devices can be reliably connected with 11ac. Alternatively, to prevent 11ac compatible devices from accidentally connecting with the old standard, one way is to set the device so that it does not connect with 11n or 11g.

Point 3 What are 4x4, 3x3 and 2x2? "Where do the differences appear?"

　In the specifications of access points, there are descriptions such as 4x4, 3x3, and 2x2. This refers to the number of antennas. "4x4" means that it has four transmitting antennas and four receiving antennas.

　In the case of wireless LAN, the number of antennas is proportional to the speed. With 11ac, the maximum speed of one antenna is 433.3 Mbps, so if there are three, it will be 1300 Mbps, and if there are four, it will be 1733 Mbps. All speed notations are theoretical numbers, but there is also a clear difference in effective speed.

Also, the more antennas you have, the more devices you can connect simultaneously. Therefore, in the case of office use where many devices are connected, the greater the number of antennas, the better the usability.

Point 4 Do you need support for beamforming and MU-MIMO?

With 11ac Wave2, beamforming and MU-MIMO functions can be used. Beamforming is the ability to send strong radio waves to a specific device. By concentrating and sending radio waves in that direction, an environment is created in which stable communication is possible even in situations where radio waves are difficult to reach, such as when the distance between the access point and the device is long.

　In a large office, there will be seats near and far from the access point, but with the beamforming function, it should be less likely that radio waves will not reach the far seats.

MU-MIMO (Mu-MIMO/Multi-User MIMO) improves simultaneous connections with multiple devices. MIMO is a function to send and receive data by bundling multiple antennas, and a function called SU-MIMO (Single User MIMO) has been used for a long time.

When sending and receiving data with multiple devices, SU-MIMO switches the connection for each device. In other words, you can only connect to one device at a time, and by switching the connection destination in a short time, you can connect to multiple devices. Therefore, when multiple devices are connected at the same time, it appears that they are communicating at the same time, but there is actually a waiting time.

MU-MIMO realizes connection with different devices for each antenna, as it appears in the word "multi-user". For example, if three MU-MIMO-compatible devices are connected to a 4x4 MU-MIMO-compatible access point, they can communicate without waiting time, demonstrating three times the processing power of SU-MIMO.

　In other words, in an environment where many employees use wireless LAN, such as an office, the presence or absence of the MU-MIMO function greatly affects usability.

Point 5 What are DFS and TPC to reduce interference with radar and effectively utilize bandwidth?

There are bands that are not being used even within the 5 GHz band. For example, there were restrictions on using bands that overlap with weather observation and satellite radar bands. If an access point uses this band, it must switch to another band when radar is detected. At that time, the DFS (Dynamic Frequency Selection) function, which checks if radar is not detected in the switched band for one minute, and the TPC (Transmission Power Control), which mitigates interference with satellite radio waves, were required.

　Using DFS or TPC makes it possible to use that band, but from the user's point of view, the connection with the access point will be interrupted for one minute, making it extremely inconvenient. Therefore, it was not used much.

　However, the unused DFS band is actually wider than the usable band. If you want to make more use of wireless LAN in the future, this is the band you definitely want to use. Therefore, technology is being installed to eliminate the confirmation time of one minute. This is also a recommended function for environments where many employees use wireless LAN at the same time.

Point 6Which is better, external or built-in antenna?

　There are two types of access points: an external type with an external antenna and a built-in type with an antenna housed inside the housing. Both are designed so that the accuracy of the antenna is the same, but the external type has the advantage of being able to change the angle of the antenna. If you can change the angle of the antenna, you can flexibly adapt to the installation location of the access point.

　In some cases, the access point can be installed in the center of the room, and in other cases, it can be installed in the corner of the room. If it is in the center, it transmits and receives radio waves evenly in all directions, but if it is installed in a corner, the direction is limited. If it is an external type, by changing the angle of the antenna, it can be installed so that it is easy to communicate in the direction where there are many people.

Point 7 What is the equal communication function that is essential for stable communication?

　A type of access point equipped with an equal communication function has also appeared. When connecting with multiple devices, wireless LAN gives priority to the device that communicated first. For example, if there is a device that has played back video content for e-learning, etc., that device will preferentially use the bandwidth. Therefore, even if you try to play the video content on another device, you will be in a disadvantageous situation such as the video being apt to be interrupted.

　The solution to this problem is the equal communication function that equalizes the communication speed of connected devices. Since the communication time is equally allocated to the connected devices, there is no advantage or disadvantage.

Point 8 IT equipment is vulnerable to heat - what about heat countermeasures?

　Wireless LAN access points are not always installed in a good environment. If it is an office space where people work, the air conditioner will be turned on and the temperature will be appropriately controlled, but it may be placed on the ceiling or in the corner of the corridor where heat is likely to accumulate.

　As is well known, IT equipment is vulnerable to heat. When it gets too hot, not only does the processing capacity drop, but there is also concern about thermal runaway and freezing. Wireless LAN access points are no exception. When choosing an access point, make sure it can withstand high temperatures.

　In addition to being able to withstand the summer, access points with excellent heat countermeasures can be installed in places where heat is likely to accumulate, such as warehouses.

　This time we explained about 11ac, which is currently the mainstream, but 802.11ax is also being formulated as the next-generation standard. This aims at 9.6 Gbps, about 1.5 times faster than 11ac. It is also equipped with MU-MIMO, which has further enhanced functions, and is expected to improve communication with simultaneous connections with more people.

　By using a wireless LAN, you will be able to work using your PC or tablet wherever you are, as long as you are in a place where radio waves can reach. For that, an access point like 11ac that can stably send and receive radio waves at high speed and in a wide area is essential. Models equipped with beamforming, MU-MIMO, equal communication functions, etc. are suitable so that failures such as communication interruptions are unlikely to occur even if many employees access at the same time. We would like to recommend an access point based on the number of employees in the office, the number of users communicating at the same time, and the office environment.

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