Public Land Mobile Network

Network Architecture

The infrastructure of the system is divided into geographical regions divided into cells, each served by a base station. A public land mobile network coordinates with other operator networks to support international roaming and handovers. It connects to the public switched telephone network and packet data networks to allow subscribers to route calls and access internet services.

Operational Selection

User equipment continuously monitors the signal strength of nearby base stations to select and register on the most appropriate available operator network. This selection is guided by lists of preferred and forbidden network codes stored on the device’s subscriber identity module. The terminal switches to a different network when its home coverage is unavailable and a roaming agreement is in place, evaluating the signal quality of neighboring cells to ensure that the selected network provides a stable and high-speed data connection.

Verification Protocol

Telecommunications test beds use base station emulators to verify that a device can scan, identify, and register on different network codes. The verification tests check that the device complies with the selection priorities and that it handles network reject codes correctly. This testing is required to guarantee that the device can roam between different carriers without loss of service.