Need a signal boost

Lately my husband has been complaining about the signal on his cellphone. See the problem that he is having is that, he doesn't get any signal when he is inside the building of his workplace. I don't have any problem with the signal when I am at home but it's just sort of anything since whenever I call him, it always goes to voicemail and there are times that he is not even getting the missed calls on his list.

What happens is that, he has to go outside the building so he can use his cellphone. And often times I have to call his work cellphone just to get a hold of him. Now I don't really like calling him on his work cellphone, but there's a few times that I did because of emergency.

I think what we really need is a cell signal booster. You know to make the signal better or at least for my husband to get something and be able to use his phone even though he is inside the building.

I wonder if those signal booster will help our cellphone issues.