I think the walls in our house have chicken wire in them because it acts like a Faraday cage. WiFi just doesn’t penetrate walls. So I use power-over-ethernet to fill every room with wi-fi. I attached a power-over-ethernet unit to my cable internet modem and plugged it into an AC outlet. In the other rooms of the house, I use wi-fi power-over-ethernet adapters. The internet connection travels through the power wiring of the house. It’s not as fast as a wired ethernet connection, but it works well for our purposes, including streaming video. Here’s a good starter kit on Amazon.
An easy way to wire your house for Internet: wi-fi power-over-ethernet
