Users open up the Signal Booster app by tapping on the icon from the home screen, wait for it to close, and then watch for an improvement in the voice or data signal. There is no fancy processing done as the app merely offers a way to shut down a weak cell connection and open up another one, with hopefully a stronger connection.
Signal Booster is available from BigBoss and costs $.99. The first untethered jailbreak for iOS 7 became available just last month. Those interested in the process can follow our step-by-step directions on how to jailbreak your iOS 7 powered iPhone with the understanding that you could end up bricking your expensive device. Even if you're successful, you will void your warranty.
Signal Booster will increase the voice and data signal of your jailbroken Apple iPhone
source: SignalBooster via RedmondPie