What is the PLMN in LTE?
In this article, we’re going to discuss PLMN, an essential concept in LTE networks. If you’ve been following our previous topics, you’ve learned a lot about the components and technologies that make LTE so effective. Today, we’ll dive into what PLMN is and how it functions within the LTE ecosystem.
PLMN stands for Public Land Mobile Network. It is a key term used to describe the mobile network infrastructure that enables communication between mobile devices and the core network. The PLMN is essentially the identifier for a mobile operator’s network and it is used to manage and differentiate between different mobile network providers.
When you use your smartphone, it connects to a network provided by a specific operator. This operator’s network is identified by its PLMN. In simpler terms, PLMN can be seen as a unique “identity” for a mobile network, which helps the mobile devices know which network they are connecting to and which services they are allowed to use.
The PLMN is identified by two main parameters:
- MCC (Mobile Country Code): The MCC is a 3-digit code that identifies the country of the network. For example, the MCC for the United States is 310, and for India, it’s 404.
- MNC (Mobile Network Code): The MNC is a 2- or 3-digit code that uniquely identifies the mobile network operator within a country. For example, in the United States, Verizon’s MNC is 0, and AT&T’s is 410.
When your phone connects to a network, the PLMN allows the device to identify which country and operator’s network it should connect to. The PLMN is important for ensuring that your device can roam between different regions, ensuring that you can access voice, data, and other services as you travel.
How does PLMN function in LTE?
In the context of LTE, PLMN plays a crucial role in cell selection and handovers. When you power up your phone, it scans for nearby LTE cell towers. Each of these towers broadcasts a PLMN identifier. The phone uses this identifier to decide whether it should connect to the current network or search for a stronger signal with a different PLMN.
Additionally, PLMN is integral to network selection. When you’re in an area with multiple networks available, your device will use the PLMN information to select the most appropriate network. This is particularly important when you are traveling and moving between regions, as it helps determine which operator’s network you should connect to.
The concept of PLMN is also tied to the network’s access control. For example, if you’re trying to connect to a network that’s not authorized for your SIM card, the network will reject the connection. This is controlled by the PLMN settings on the SIM card, which ensures that you can only connect to your specific operator’s network or an allowed roaming network.
Real-World Scenario: Imagine you’re traveling abroad and your phone automatically connects to a local network. The device identifies the network based on its PLMN and uses the MCC and MNC codes to establish the appropriate roaming settings. This ensures you can make calls, send messages, and use data just as you would at home, as long as the roaming agreements are in place.
To summarize, PLMN is a foundational element of mobile network communication, ensuring that devices connect to the correct network and receive the services they need. As we have discussed in previous articles, the smooth operation of an LTE network depends on many underlying systems, and PLMN is one of the key components that ensures your mobile device works seamlessly across different regions and network types.