"Wireless exceeds wired", Buffalo's top wireless LAN router "WXR-2533DHP" interview that enables Gigabit beyond Wi-Fi communication Interview with developers

Buffalo will become the company's high-end model in June 2015 Wireless LAN router "WXR-2533 DHPWe released the. Simultaneously enable Wi-Fi communication with multiple terminals "MU-MIMO"Or correspond to four movable antennas and"Beam formingAbout using a model that you can deliver aimed radio waves to the places you want throughout the house using thePosted an article alreadyHowever, since I succumbed to the development team where I could infiltrate the development department that I can not enter normally this time, I was able to listen to development confidential stories and show the facility that is the key to development It was.

Performance beyond built-in antenna 11ac 4x4 Wi-Fi router with large movable antenna | WXR-2533DHP | BUFFALO Buffalo
http://buffalo.jp/product/wireless-lan/ap/wxr-2533dhp/


So I arrived at the headquarters in Buffalo.


When entering the lobby from the entrance, the official character of Buffalo "Buff & Faro"Greeted me.


In the lobby space, the current line-up products were lined up, but at the time of visiting the interview, WXR-2533 DHP was not placed yet.


Basically, Wi-Fi router, external HDD, etc. were lined up, but for some reason only one unit found quite different products in different view of the world. This is a high-res compatible digital music library developed by Buffalo as a DELA brand "N1Z"was. As a high-end audio equipment that excluded any compromise, the price was about 700,000 yen, which is really high end.


Furthermore, I found this kind of equipment. HDD which adopted the transparent body which developed for the campaign in the past, of course, the real hard disk is contained in contents.


It also seems that the controller was built in and it was possible to see the way the arm actually moves and works.


Also, "buffalo = water buffalo" means that figurines with water buffalo were also on display.


I tried listening to people in Buffalo
After having me observe the inside of the company, I will listen to stories from the people who actually participated in product planning and development. Mr. Hiroaki Naruse who was in charge of development from the left, Mr. Takayoshi Toyama on behalf of the marketing department, and Mr. Yuhei Hamaoka who is in charge of public relations.


Toyama:
The WXR - 2533DHP we released this time is equipped with an external 11in 4 x 4 antenna of a large movable type, enabling communication to multiple terminals at the same time without lowering the speedMU-MIMO"This is our first response model. In addition, we can realize high-speed Wi-Fi communication by efficiently delivering radio waves to the targeted place corresponding to the conventional "beam forming".

By installing 4 antennas to 4 × 4, the maximum throughput achievable with this model is 1733 Mbps in theory. However, since this is the "theoretical value" to the last, it is unlikely that this speed will come out in the actual usage scene, but when actually conducting the verification using the environment close to the ordinary household,1258 MbpsIt has succeeded in producing effective throughput. Although it is specified as "1258 Mbps" in the product package, this is actually measured value which can be measured, so there is no problem even if you believe the number as it is (laugh).

Of course, in order to actually demonstrate this performance it is necessary to have 2 4 × 4 compatible devices, so it is true that anyone can experience "1 gigabit over" speed right now . However, saying that the speed exceeding 1 Gbps actually occurred in the communication environment using Wi-Fi, this has already reached the dimension which is not an overstatement even if saying "wireless has exceeded wired line".


In addition, since this unit is equipped with MU-MIMO, it is designed to maintain high communication speed even when multiple terminals are connected via Wi-Fi at the same time. In the conventional "MIMO" state, when a plurality of terminals are connected, "time division" for performing communication by separating the communication for each terminal with time has been performed, so that the time of "waiting" inevitably arises It was. This caused the phenomenon that the perceived speed slowed down, but in the newly introduced "MU-MIMO (multi-user MIMO)", it is possible to simultaneously up to 3 terminals at the same time As communication becomes possible, environments that are almost unaffected by actual use are possible.

However, in order to use this MU-MIMO, it is necessary for the handset side to comply with this standard, but there is almost no corresponding terminal in the present situation (bitter smile) Smartphone etc. finally correspond to MU - MIMO. In the future we will be able to fully demonstrate the performance of this model if compatible devices come out one after another, but apart from that, we also focused on the other merit of having four antennas with this product, I went.

◆ The smartphone was affected by the communication speed depending on how it was placed
It is a little unknown, but most of smartphones may affect Wi - Fi communication speed depending on the angle you hold the handset and hold it in your hand. This is a problem that arises because the degree of freedom of the layout of the transmitting and receiving antennas has become low as the terminal becomes smaller and the angle at which radio waves can be efficiently picked up is limited. In this product, we take advantage of the advantage of mounting a 4 × 4 antenna and we are improving to be able to communicate stably under any circumstances.

In the graph of the image below, we compare the effective speed when connecting to the conventional model (blue) and WXR - 2533DHP (red) using iPhone 6. In the case of a blue graph, depending on the angle of the terminal, the communication is stopped depending on circumstances, while the red graph is not affected by angle at all, it is stable from about 145 Mbps to about 190 Mbps I succeed in giving out speed. Stability is of course also important, but it is also important that the base speed itself is quick to make a difference.


Unlike PCs, smartphones and tablets are greatly beneficial to carry around and use freely, but there is a part where freedom was pushing the legs in reverse. In WXR - 2533 DHP, in order to solve such a problem, the numerical value on the spec is of course important, but we have been developing it with particular attention to such practical usability.

◆ Actual development scenery
I heard the aim of the development of WXR-2533DHP at a glance, and this time Mr. Naruse explained that I was involved in the development of the actual machine and explained the actual development scenery.

Naruse:
From Toyama was "development that sticks to usability", but, of course, as a human being of engineer side like myself, of course I do not want to lose the numbers of other manufacturers (laugh) .


At the stage of development, we have obtained chip chips for evaluation actually planned to be used from chip makers and have verified how much speed actually comes out while changing various conditions.

(Here, we showed the equipment to verify the antenna by installing it at various angles, but unfortunately it is not possible to shoot because it is a top secret. Install antennas at various intervals and angles on the test stand It was a machine made to be able to)

It is fairly important to thoroughly pursue the performance at the verification stage, so it will not be possible to change anything if the board actually used for the product is completed, so we carried out fairly detailed verification at the initial stage. What I found during the verification process is that unless the distance between the antennas is increased to some extent, isolation between the antennas can not be obtained. Moreover, when arranging the four antennas at equally spaced intervals, it became clear that only two in the middle really did not get the speed.

GIGAZINE:
Indeed, that is interesting.

Naruse:
This seems to be due to the fact that the inner two antennas are sandwiched in the outer antenna after all. As a result of repeating such verification, in order to maximize the performance using the chip installed this time, set the antenna spacing to "8 cm, 9 cm, 8 cm" and arrange it in a row next to each other It came to the conclusion that it is the best layout.


And, once the width of the antenna is decided here, the width itself of the router chassis will be decided naturally. To be honest, there was also an opinion that "from the inside of the prototype machine is too large" (laugh), then it will be talked about which size and performance to take. So, after considerably stuffing about that story, it is the performance in the end after all.

GIGAZINE:
It is still a flagship machine.

Naruse:
That's right. Through such circumstances, this product has become a larger casing than before.

In addition to that, what I had to think about was the problem of heat coming out of the board. There is a CPU on the board, there are 4 chips in total for each antenna controlling the data input / output, and there is also an amplifier for the antenna, which is exactly the state of "hanging in the heat". As a result, there was quite a lot of heat from the board, so some people said that it was "with a computer a long time ago" depending on the person.


Naruse:
However, as our company also assumes use at ambient temperature of 40 degrees environment, it is necessary to guarantee the performance that you can use with confidence even if you actually bought it.

There is such a background, it gently rises when you see the middle part of the enclosure, but this is the result of considering the internal airflow. When the main body is installed vertically, the air that entered from the slit that entered the part close to the foot is warmed inside and goes out to the top. I calculated the flow and designed the shape of the main body.


Furthermore, when it is installed vertically, it is still not good, but the problem is the case of landscape placement. It made it difficult to create a flow of air like a vertical place when laying it sideways, so I designed it so that the heated air can successfully escape up from the bottom by opening a lot of holes in the bottom part.


Naruse:
I will return the story to the antenna, but there are times when you know that you put the smartphone at various angles and measure the speed, the throughput changes unexpectedly due to a slight difference in placement. This phenomenon occurs because it is affected by the performance of the antenna module mounted on the board and the layout of the ground plane (GND plane) which affects reception of radio waves placed on the board.

So, with this product, there are 4 antennas, and it is possible to turn it in the direction you like, so it is also possible to create an optimum reception environment according to the usage situation of users by emitting radio waves in various directions It is one of the aims. For this reason, I am using an external antenna this time. By optimizing four antennas, we realize a throughput of 100 Mbps or more at all times regardless of the angle of the smartphone, realizing a stress-free environment in various situations.

A room called "anechoic chamber" for measurement is set up in our headquarter building, but during development it is necessary to perform various verifications in it or after actually obtaining technical certification I am doing various exams even in the outside environment. In addition, we are introducing an actual house for experiments by saying that it is close to the usage scenes of general users, and we are developing such as to measure the communication speed by reproducing various conditions there.


I think that you can see that the number "1258 Mbps" is written when you look at the product package, but since this is the actual value that I got when actually measuring with a building for verification, I think that it is no problem to have it understood as a figure that can be realized sufficiently in the environment of. In that sense, I think that it is finished as a product that can simultaneously give the performance as a product and the merit of being actually used by the user.

Toyama:
Especially if you are a large-sized house or a user living in a spacious room, I think that there are times when you feel that you can not satisfy enough with conventional wireless routers. In such a case, when the name "4 × 4" like this product comes out, the figure is also big, and I think that you can buy with expectation again. Even so, I do not get the performance as I expected, or I think that throughput will be affected by the orientation of the smartphone, especially when speaking of this top product, this product will be a bit different. To be honest, the manufacturing cost has been raised by enlarging the enclosure, but I was trying to make it possible for customers to fully feel the benefits and benefits of the new technology installed on them is.

However, in order to give out its performance, even if asking blindly, "Please set up the antenna well," I think that I do not usually know. Therefore, at our company, we prepare a template for adjustment called "Antenna installation guide" in the product package, so we incorporate ideas that make it more accessible to the best environment.

So, the state of the adjustment using "Antenna installation guide" is like this. Apply the template displayed in full size like this ... ....


It is OK if it matches the angle of the antenna perfectly.


Of course not only the angle seen from the front, but also templates for adjusting the angle in the front and back direction are prepared as well, so it was possible to adjust the antenna at the 3 dimensional level.


Toyama:
Recently, even on smartphones, applications that can display the strength of radio waves in real time can be used for free, so it may be interesting to have a test of what the user's environment is like You do not. Especially, I think that you can feel a big difference when you are communicating across a different floor, such as a room separated by a wall.

Actually, as a trend of about a year and a half here, the relay machine of Wi - Fi is able to sell very well. In the environment of your home, for example, I think that there is a usage scene that you enjoy a movie while taking a bath, or bring in a tablet to a bedroom and watch the net, but by all means the radio waves are weak, I think that you are often worrying about going into data reading state immediately. Especially when smartphones and tablets become popular, the way of thinking is changing from the era in which you have been making a wireless LAN of a stationary PC as before. We have done product development so that we can respond to such latest use scenes and needs.

Although it often shows peak performance as well as explaining the actual product, it shows the performance as "horsepower" of the product to the last, there is a slightly different perspective in terms of actual user benefit It becomes necessary. In the past, I often appealed performance by showing numerical values, but this time I think that you can mainly feel the aspect of actual merit such as "wide coverage area" and "stable communication" It is place.


This time there are things that the main body has become bigger, but another merit by that is born. Although you can understand if you see the back side, the part to insert the power cable and LAN cable is laid out in a position deeper than the main body side. By doing this, it becomes possible to hide the cable well on the back side when actually installing the equipment, making it difficult to see, and it is possible to use it in a state that it is refreshed and put together.

Naruse:
In addition, it has worked in a good direction that it became possible to separate the noise source disturbing communication due to the larger size of the main body. As you can see the board, the USB 3.0 terminal that connects an external memory etc is quite a corner, but this is one of the countermeasures against noise. Since the noise emitted by the USB 3.0 port often interferes with the radio in the 2.4 GHz band, it is not a good idea to bring it closer to the Wi-Fi signal path. However, one of the main points is that as the body became larger, it became possible to create an environment to fully demonstrate the original Wi-Fi performance.

In addition, the improvement point of this time is that the "guest button" is installed as the actual button. For example, it is a function that can be set with one touch when providing a Wi-Fi environment to a guest who has been temporarily brought to his / her home, such as a friend of a user or a friend of a child. Actually, this function itself was implemented by software in the past, but in order to actually use it, it was necessary to open a setting screen on the PC and make a troublesome setting to check the function.


However, from the viewpoint of user benefits, since it is well understood that this is really inconvenient, it is easy to provide a Wi - Fi environment without troublesome setting just by touching a button on the main unit, It incorporates a mechanism that can shut down from a private network and create a safe state in terms of security.


◆ Necessity of development · I showed you "Anechoic chamber"
After asking various aims and thoughts about product planning and development, I asked them to show facilities called radio anechoic chambers installed in the head office building. It is a room which newly made a room in the floor where there is an office and spreads special absorption material which absorbs radio waves inside, and the appearance can not be taken also here. I succeeded in photographing the inside, so the situation looked like the following.

An electromagnetic wave anechoic chamber with a large one-room apartment has a blue absorbing material with a wedge-like shape on one wall except the floor, and a white protective member that keeps the shape of the absorbing material.


Two large measuring antennas were installed in the room. The two are used to measure different radio waves and are used for verification in various environments.


Even at the development stage of WXR - 2533 DHP, it seems that the body was installed and verification was done in this way. In the anechoic chamber, it is possible to shut out the diffused reflection of the radio wave inside while simultaneously blocking the radio noise from the outside, so highly accurate measurement is possible. Although it is at the forefront of development, the scene of corrugated cardboard assembled with a gum tape is surprisingly surreal.


In development, first of all, we do all kinds of verifications in such facilities, and after acquiring technical certification, we perform verification in the actual outside space and returning to this facility again, the performance brush It seems that up has been done.


In such a situation, the interview was completed while taking over a lot of company secrets / photography NG. As a model located at the high end among the buffalo, it has been well conveyed that it is a model developed with a considerable amount of effort. In the GIGAZINE editorial department, I borrowed two "WXR - 2533DHP" and actually challenged communication exceeding gigabit at the editorial department, and the pattern will be released soon.

◆ Continued
Performed speed measurement of Buffalo's high-end wireless LAN router "WXR-2533DHP", I examined the potential of Wi-Fi communication exceeding gigabit - GIGAZINE