Between thick walls, reinforced concrete or in buildings with several floors, there is always WiFi (WLAN) problems. There is often too less WiFi strength or no WiFi available. Even the latest wireless technology brings no success.
You still do not have to get along without WiFi!
With a set of at least two "powerline WiFi network adapters" you can bridge the thickest walls.
The principle is simple:
Plug an adapter into the socket next to the DSL router and connect it by cable to the router, the other ends up in the socket in the room you want to provide WiFi.
Buy a "starter set" of two adapters, they connect automatically after plugging into the socket.
Both sockets must be connected to the same electricity meter.
No overvoltage protection (lightning protection) may be inserted in the socket.
Best Powerline Network Adapters to Buy: search Google for "best powerline WiFi network adapters"
Here are some reports in the English language press: