5G NAS and RRC Signalling Parameters for Voice Service Support

Last updated on Dec 14, 2023

In 5G, the NAS (Non-Access Stratum) and RRC (Radio Resource Control) signaling parameters play crucial roles in enabling voice services and ensuring efficient communication between the user equipment (UE) and the network. Let's break down the technical details of these signaling parameters for voice service support:

NAS (Non-Access Stratum) Signaling:

1. Registration Procedures:

Attach and Registration: When a UE attaches to the network or registers with it, specific NAS messages are exchanged. For voice service support, the registration process includes attaching to the network and updating the location information in the Home Subscriber Server (HSS).
Deregistration: When a UE detaches from the network, NAS signaling is used to inform the network about the detachment.

2. Security Procedures:

Authentication and Key Agreement (AKA): NAS signaling is responsible for initiating the AKA process, where the UE and the network authenticate each other and derive shared security keys for securing communication.
Security Mode Control: NAS signaling also plays a role in establishing and modifying the security mode, ensuring that communication between the UE and the network remains secure.

3. Session Management:

Paging: When there is an incoming call for the UE, NAS signaling is used to page the UE and notify it about the incoming session.
Service Request: The UE uses NAS signaling to request specific services, including voice services, from the network.

4. Mobility Management:

Tracking Area Update (TAU): When the UE moves to a new tracking area, NAS signaling is used to update the network about the UE's new location.

RRC (Radio Resource Control) Signaling:

1. Connection Establishment:

RRC Connection Setup: Initiates the establishment of an RRC connection between the UE and the network, allowing the UE to access the radio resources.
RRC Connection Reconfiguration: Used to modify an existing RRC connection, for example, to allocate resources for voice communication.

2. Radio Bearer Control:

Radio Bearer Establishment: Establishes radio bearers for the transmission of voice data.
Radio Bearer Reconfiguration: Modifies existing radio bearers to optimize resources or accommodate changes in service requirements.

3. Handover Procedures:

Intra-frequency and Inter-frequency Handover: RRC signaling is crucial for handing over the UE's connection seamlessly between different cells and frequencies while maintaining voice service continuity.

4. UE Capability Information:

UE Capability Enquiry and Response: The UE provides information about its capabilities through RRC signaling, allowing the network to determine the most suitable radio configurations for voice services.

5. Power Control:

Uplink Power Control (ULPC) and Downlink Power Control (DLPC): RRC signaling helps in adjusting the power levels in the uplink and downlink to optimize the communication quality and efficiency for voice services.

These NAS and RRC signaling parameters work together to establish, maintain, and optimize the communication between the UE and the network, ensuring the provision of voice services in a 5G environment. The details of these procedures can be further specified based on the specific 5G network architecture and deployment scenarios.