- You may be looking for booster rockets or signal booster, both often simply referred to as boosters.
A booster was a device that augmented the capability of another device.
In 2267, the auditory sensor of the USS Enterprise was augmented with a booster which increased its abilities by one to the fourth power. This enabled it to hear every sound on board the ship, including the heartbeats of a skeleton crew, the court martial panel, and a presumed-dead Benjamin Finney. (TOS: "Court Martial")