Identify the place where the radio waves of Wi-Fi can not reach by using the equation of physics

"The corner of this room smoothes the display of the website", "The uploading of the picture is super fast when placing the notebook PC on the elbow of the sofa on the right", sensuously find a place where Wi-Fi is easy to connect in the room Many people are looking for it. By trying to solve this problem using physics,Helmholtz equationA place where Wi-Fi is easy to connect and a place that is hard to connect is introduced.

Helmhurts | Almost looks like work
http://jasmcole.com/2014/08/25/helmhurts/

One apartment's Wi-Fi dead zones, mapped with a physics equation | Ars Technica
http://arstechnica.com/gadgets/2014/08/mapping-wi-fi-dead-zones-with-physics-and-gifs/

The physics of where to put a WI-FI ROUTER: Scientist proves that the center of your home is best for signal strength | Mail Online
http://www.dailymail.co.uk/sciencetech/article-2735856/The-physics-WIFI-ROUTER-Scientist-proves-centre-home-best-signal-strength.html

I did the simulationImperial College LondonMr. Jason Cole, a doctoral student at the University of Tokyo. Mr. Kohl modeled the movement of radio waves with the Helmholtz equation,Sparse matrixWe minimized the computer's computation of "What kind of waves are emitted from the Wi - Fi router and how will it hit the obstacle?"


The room plan of Mr. Kohl's room is like this. It improves the communication environment of this room.


First of all, this figure visualizes the communication environment when the router is placed in the corner of the room. The red circle is the place where the router is located, and the place where it is bright is where the Wi - Fi radio wave is flying. Mr. Kohl first started thinking that the radio waves around the router are strong and weakened as you go away, but contrary to expectations the radio waves are spreading in the corner of the room. While the location of the router does not affect the strength of radio waves up to that point, black spots with no radio waves are present even at adjacent places.


Let's change the position of the router. I tried putting the router on the right side of the lower floor plan, and the communication environment of the right room improved compared to the above, but the communication environment of the two bedrooms on the left worsened.


The most effective thing is to install a router in the middle of the room, but this is actually difficult to implement.


The wall of the room has a very high refractive index, but what you can see in this simulation is that radio waves are obstructed not only to the wall but also to the corner of the door or the room. This is because radio waves will weaken by hitting objects.

Also, assuming that the walls of the concrete were made of imaginable fictitious materials, it turned out that the radio waves reach much in every room. The following is a simulation, radio waves reach the room in the back regardless of the position of the router.


And the following movie added Caller's expectation plus the concept of "time".

Wifi - YouTube


A router is placed at the lower right of the room. The surroundings of the router is orange, and as you move away from the router the color changes to blue.


The range the radio waves can reach more and more ... ...


Advance to the next room. The orange part has a part hindered by the wall of high refractive index.


A reddish wave enters the upper bedroom from the door.


Although there are places where it is difficult for radio waves to reach in the end, it has become an environment where radio waves are easy to reach except for the bedroom on the lower left.


A real experiment about the communication environment has not been done yet, but in the comment column of Ms. Kohl's blog, "Unique suggestion of trying to attach a router to an automatic vacuum cleaner?" Is also made.

An Android application that simulates the communication environment is also developed by Mr. Kohl using the layout of my room, and it is possible to download it from Google Play at 99 yen.

WiFi Solver FDTD - Google Play Android application
https://play.google.com/store/apps/details?id=com.jasmcole.wifisolver