In the context of Long-Term Evolution (LTE) networks, the term “LAC” typically refers to “Location Area Code.” However, it’s important to note that the concept of Location Area Code is more commonly associated with legacy cellular technologies like GSM (Global System for Mobile Communications) and not directly applicable to LTE. Instead, LTE networks use different identifiers and mechanisms for managing location information.
GSM and Location Area Code (LAC):
In GSM networks, including 2G and 2.5G technologies, the Location Area Code (LAC) is a parameter used for tracking and managing the location of mobile devices within the network. The GSM network is divided into Location Areas (LAs), each identified by a unique LAC. LAs consist of multiple cells, and when a mobile device moves from one LA to another, it triggers a location update procedure.
LTE and Tracking Area (TA):
In LTE networks, the concept that is more analogous to the LAC in GSM is the “Tracking Area (TA).” The Tracking Area is a group of cells that are grouped together for tracking and location management purposes. When a mobile device moves from one Tracking Area to another, it may trigger a Tracking Area Update (TAU) procedure.
Key Aspects of LTE Tracking Area:
1. Tracking Area Identifier (TAI):
The Tracking Area Identifier (TAI) is used to uniquely identify a Tracking Area within an LTE network. It consists of the Mobile Country Code (MCC), Mobile Network Code (MNC), and Tracking Area Code (TAC).
2. TAC and Tracking Area:
Similar to the LAC in GSM, the Tracking Area Code (TAC) helps identify a specific Tracking Area within the LTE network. When a mobile device moves across Tracking Areas, it may initiate a Tracking Area Update to inform the network of its new location.
3. Mobility and Location Management:
The Tracking Area concept in LTE is crucial for mobility and location management. It allows the network to efficiently track the location of mobile devices and optimize the routing of data to and from these devices.
4. TAU Procedure:
The Tracking Area Update (TAU) procedure is triggered when a mobile device moves to a new Tracking Area. During TAU, the device informs the network of its new location, allowing the network to update its records and maintain seamless communication.
5. Optimizing Signaling Overhead:
The design of the Tracking Area concept in LTE is intended to optimize signaling overhead. By grouping cells into Tracking Areas and updating the location information at the Tracking Area level, LTE networks can reduce the frequency of signaling updates compared to updating at the individual cell level.
LTE and Mobility Management:
LTE networks are designed to efficiently manage the mobility of users across cells and Tracking Areas. The use of Tracking Areas and the TAU procedure helps in optimizing handovers and ensuring that communication sessions remain uninterrupted as mobile devices move within the network.
Conclusion:
While the term “LAC” is more commonly associated with GSM networks, LTE networks utilize the concept of Tracking Areas to achieve similar goals in terms of location management and mobility tracking. The Tracking Area concept in LTE plays a crucial role in maintaining efficient communication as mobile devices move across different areas within the network.