Dell Inspiron 5759 next room Wi-Fi issue

Hello, 

I have problem with Wi-Fi connection on my Dell Inspiron 5759 17" laptop. If I am in the living room (where is my router) everything is ok. But when I am in the next room, my bedroom, and I try to enter some website it total crash my wifi and internet isn't working on any device. And when I disconnect my laptop from Wi-Fi, internet came back in about one minute. 

I searched on net and tried a lot of things but any of them solved the problem. But I found that if I connect my laptop to my Wi-Fi using hotspot on my phone it works well.

Can someone help solve this? It's not the end of world but it's very annoying.

Thanks