^Feature^NSA 5G^SA 5G|
|Voice|VoLTE (4G)|VoNR (Native 5G)|
|Core Network|4G EPC|5G Core (5GC)|
|Latency|Higher (depends on 4G)|Ultra-low (~5-10ms)|
|Network Slicing|Not Supported|Supported (e.g., dedicated voice slices)|

===== 5G NSA Architecture =====

{{  :5g_nsa_architecture_key_concept.png?nolink&400  }}

Control Plane: Managed by 4G LTE (via the 4G Evolved Packet Core (EPC)).

User Plane: Uses 5G NR for high-speed data, but voice relies on 4G VoLTE.

Dual Connectivity (EN-DC): Your device connects both 4G and 5G simultaneously, but voice and data are split between two.

What happens during a voice call on NSA 5G?

  - Voice Call Initiation:
      * Your phone uses 4G LTE to set up the call via VoLTE(IMS core).
      * The 5G NR connection is temporarily suspended or underutilized for the duration of the call.
  - Data During the Call:
      * If the carrier supports EN-DC (E-UTRA-NR Dual Connectivity):
        * 5G NR continues handling data (e.g., browsing, streaming) while the voice call runs over 4G VoLTE.
      * If EN-DC isn't supported:
        * Data falls back to 4G LTE during the call (just like in pure 4G VoLTE).
  - Call Termination:

After the call ends, your device re-establishes the 5G NR connection for data (if available).

===== 5G SA Architecture =====

{{  :5g_sa_architecture_key_concept.png?400  }}

Key Architectural Differences:

Full 5G Core (5GC): SA uses the new 5G Core network (not 4G EPC) for both control and user planes.

No 4G Dependency: All functions (voice/data) run natively on 5G without LTE anchors.

Single RAN: Uses only 5G New Radio (NR) base stations (gNBs), not LTE eNBs.

Key Components

  * AMF (Access & Mobility Management Function): Handles connection management
  * SMF (Session Management Function): Manage user sessions.
  * UPF (User Plane Function):  Routes data traffic (It is the equivalent to 4G's PGW/SGW).
  * UDM (Unified Data Management): Authentication / Authorization
  * gNB: 5G base station

What happens during a voice call process (VoNR)?

  - Call Setup: Uses Voice over NR (VoNR) through IMS core without 4G fallback.
  - Data Continuity: Maintains 5G data connection simultaneously.
  - No Session Suspension: Unlike NSA, SA maintains full 5G capabilities during calls.

SA Advantages:

  * Ultra-low Latency (<;1ms theoretically)
  * Network Slicing Capabilities
  * True end-to-end 5G Security
  * Massive IoT Support (mMTC [Massive Machine-Type Communications])
  * Enhanced Mobile Broadband (eMBB)

Deployment Challenges:

  * Requires complete 5G core deployment.
  * Limited device ecosystem (though improving)
  * Higher infrastructure costs