A fixed station that uses radio waves to communicate with mobile devices. It serves as the link between the user's device and the carrier's network.
Base stations range in size and area of coverage. Some may cover a radius of several kilometers while others cover only a few city blocks. Most stations transmit in all directions but there are also directional antennas aimed at a specific direction.
Usually base stations are owned by a single carrier but may offer roaming coverage for other networks.