Using a repeater provides the best (permanent) solution, although the issue is, with LTE being on the scene now, many of the current products on the market won't work since they lack the appropriate frequency bands. 850/1900 dual band repeater systems would likely not suffice if you need LTE. Verizon or ATT?
Example of one 4G/LTE solution from Wilson (repeater- amp/external antenna). Multiple levels may require a second unit on a different floor/room. You may have to contact Wilson directly to figure out which product they recommend for the additional floor/rooms. YMMV. Apprently this one works w/ T-Mobile too. Who knew.
Large home/complete building system
They advantage of these systems is they can work with multiple cellular providers, and do not have any monthly fee, unlike the home broadband/wifi connecting solutions from Verizon & ATT.
I live with my Wife who has an iPhone 5, I have an iPhone 4S, and our five children have a variety of smartphones. We live in a 5000 sq ft house, with two floors. Some areas of the house are dead for telephone reception. (I just installed a new Netgear R6300 router and a Belkin N300 Dual Band Extender, so WiFi is at full strength everywhere.)
Does anyone what I can do or what I can get to increase the telephone power to eliminate the dead spots in the corners of the house?