Meaning
Initial synchronization procedure identifies the most suitable base station for a mobile terminal to establish a connection. Cell selection occurs immediately after power on or when a device exits airplane mode. It involves scanning supported frequency bands to find the strongest available signal that meets the quality criteria.
Signal Quality
The modem measures the reference signal received power and the reference signal received quality for every detected carrier. During cell selection, these measurements are compared against the selection criteria stored in the firmware. If the values fall below the required threshold, the device continues scanning other frequencies.
Selection Strategy
Operators define priority levels for different frequency layers to manage network load and coverage. The cell selection algorithm typically favors higher frequency bands for capacity before falling back to lower bands for better building penetration. This logic ensures that the device registers on a cell that can provide the necessary bandwidth for its service class.
It prevents the overloading of certain bands while others remain underutilized. The internal look-up table determines the scan order.
Network Registration
Successful completion of this process allows the device to read the system information blocks. Once the cell selection is finalized, the terminal is ready to initiate a random access procedure to attach to the network. This state must be reached before any data transmission can occur.
