The PRL is built and provided by your carrier, and used when your phone is trying to connect to the nearest cell tower.
It indicates which radio bands, sub-bands, and service provider IDs will be searched for, then allows the phone to connect to the correct tower.
Due to our reliance on these types of phones, for both work and personal use, when we encounter poor reception it can significantly affect our lives.
When you are in a moving car or train your phone is constantly looking and switching to the closest cell tower.
While repeaters have been around for several years, femtocells are relative newcomers to the mobile scene.