A mobile number is more than just a string of digits; it acts as a unique identifier that allows a mobile device to connect to and communicate over a cellular network. The process of connecting a mobile number to the cellular network involves several technical steps and infrastructure components working together to enable voice calls, text messages, and data services.
1. Mobile Number as an Identifier
A mobile number, often called the MSISDN (Mobile Station International Subscriber Directory Number), uniquely identifies a subscriber within the global telecom network. It is linked to the subscriber’s SIM card and the mobile device. However, the mobile number itself is not directly involved in radio communication; it functions as a logical address used for routing calls and messages to the correct device.
2. SIM Card and IMSI
Inside the mobile device, the SIM (Subscriber Identity Module) card holds a unique identifier called the IMSI (International Mobile Subscriber Identity). The IMSI identifies the subscriber to the cellular network securely and is used for authentication.
When a device powers on, it sends the IMSI to recent mobile phone number data the cellular network.
The network verifies the IMSI and authenticates the subscriber to grant access.
The IMSI is linked to the mobile number (MSISDN) in the operator’s subscriber database.
3. Registration with the Cellular Network
Once authenticated, the mobile device registers with the cellular network’s infrastructure:
Location Update: The device signals its location by connecting to a nearby cell tower (Base Transceiver Station - BTS). The network updates the subscriber’s location in its Home Location Register (HLR) or Home Subscriber Server (HSS).
This registration allows the network to know which cell site the mobile is connected to, enabling efficient routing of incoming calls and messages.
4. Radio Communication Setup
The mobile device and the network establish a radio link over a specific frequency band allocated by the network operator:
The device scans for available cells and chooses the one with the best signal.
It then establishes a connection via the Base Station Controller (BSC) or Radio Network Controller (RNC), which manages radio resources.
The network assigns a temporary identifier called a Temporary Mobile Subscriber Identity (TMSI) to enhance privacy by masking the IMSI during communications.