A base station controller (BSC) is a critical mobile network component that controls one or more base transceiver stations (BTS), also known as base stations or cell sites. Key BSC functions include radio network management (such as radio frequency control), BTS handover management and call setup.

A BSC works with a mobile switching center (MSC) component that is external to the BTS, enabling it to provide full mobile telephony and fulfill capacity requirements. Base stations must communicate with the MSC and data must be managed as information overflow, impacting MSC efficiency. A BSC eliminates MSC base station activity management requirements, allowing the MSC to handle critical tasks, such as traffic balancing and database management.