A nice booster -- the app helps you setup the receiving antenna with the best signal, and then you place the other in the room you need more signal in.

A few people recommended a booster.

The signal booster is great , I was getting low bars before , and now I have full bars , the calling experience has increase with zero lag and my data feels much faster now , I put the thing in my living room and it effects the whole house

I have had multiple boosters in the past, but they never work well enough, this one works great