The powered cell boosters made for sprint network will work, but they have an unfortunate tendancy to lock up every couple weeks, requiring a reset. until you reset them, the ones we have used anyways tend to act like cell phone jammers rather than boosters. The exterior antenna placement is also critical. if it says 26 foot vertical seperation between the antenna and the base, 15.9 feet isn't going to cut it.
The femtocells are much more forgiving if your carrier has one available.