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5G NR Global Unique Temporary Identifier (GUTI)

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The 5G New Radio (NR) Global Unique Temporary Identifier (GUTI) is a key component in the 5G mobile communication system for user identity management and security purposes. GUTI is used to uniquely identify a user equipment (UE) within the 5G network and serves as a temporary identifier to enhance user privacy.

Here is a technical explanation of the 5G NR GUTI:

1. Overview:

  • Purpose: GUTI is designed to conceal the true identity of the user equipment (UE) while it is connected to the 5G network, providing privacy and security.
  • Temporary Nature: GUTI is temporary and can be changed periodically to minimize the risk of tracking and other security threats.

2. Components of GUTI:

  • PLMN-ID (Public Land Mobile Network Identifier): A globally unique identifier assigned to a specific Public Land Mobile Network (PLMN). It helps in identifying the serving network of the UE.
  • AMF-ID (Authentication Management Field Identifier): Identifies the Authentication Management Field (AMF) within the PLMN. The AMF is responsible for managing authentication and key agreement procedures.
  • M-TMSI (Mapped Temporary Mobile Subscriber Identity): A temporary identifier assigned by the network to identify the UE within a tracking area.

3. GUTI Structure:

  • The GUTI is a 64-bit identifier, typically represented as a hexadecimal number.
  • It is composed of the PLMN-ID (16 bits), AMF-ID (8 bits), and M-TMSI (32 bits).
  • The combination of these three components ensures the uniqueness of the GUTI in the 5G network.

4. GUTI Allocation and Update:

  • Initial Allocation: When a UE attaches to the 5G network, the network allocates a GUTI to the UE, typically during the registration process.
  • Periodic Update: To enhance security and privacy, the GUTI is periodically updated. The UE and the network negotiate the update procedure to ensure that the UE gets a new GUTI without interrupting the service.

5. Security Aspects:

  • Confidentiality: GUTI helps in ensuring the confidentiality of user identity by using temporary identifiers.
  • Integrity: The GUTI is protected against integrity threats to ensure that it is not tampered with during transmission.
  • Authentication: The GUTI is used in authentication procedures to verify the identity of the UE and ensure that it is authorized to access the 5G network.

6. Use in Mobility Management:

  • GUTI plays a crucial role in mobility management procedures, such as tracking area updates and handovers, by allowing the network to track and manage the movement of the UE without compromising the user's privacy.

5G NR GUTI is a temporary and globally unique identifier used to manage user identity, ensure privacy, and enhance security within the 5G mobile communication system. Its structure and periodic update mechanisms contribute to the overall security and efficiency of the 5G network.