ENDC & NEDC

ENDC

Eutra / NR Dual Carrier interworking type where LTE serves as the Main Cell Group (MCG) and NR as the Secondary Cell Group (SCG).

NEDC

NR/Eutra Dual Carrier interworking type where NR serves as the Main Cell Group (MCG) and LTE as the Secondary Cell Group (SCG).

LTE

Long-Term Evolution, a standard for wireless broadband communication.

NR

New Radio, the radio access technology for 5G networks.

MCG

Main Cell Group, the primary cell in a dual carrier configuration.

SCG

Secondary Cell Group, the supporting cell in a dual carrier configuration.

Deployment of ENDC

The dominant form of LTE-NR interworking, utilizing an LTE Core Network.

Traffic Management in ENDC

Downlink traffic is always split between LTE and NR; uplink traffic can be managed through two options.

Uplink Traffic Option 1

All uplink traffic is routed through LTE only.

Uplink Traffic Option 2

Uplink traffic is split between LTE and NR, with the ratio configured by RRC (Radio Resource Control).

UE Interaction in ENDC

User Equipment (UE) detects the SSB (Synchronization Signal Block) of the NR cell and performs the RACH (Random Access Channel) procedure to NR.

Deployment of NEDC

Primarily specified in standards with rare real-world implementations.

Traffic Management in NEDC

Similar to ENDC but with NR as the primary cell.

UE Interaction in NEDC

Similar to ENDC but focused on detecting NR.

Summary of ENDC

The prevalent method for LTE-NR interworking, leveraging LTE as the main cell and NR as an enhancement.

Summary of NEDC

Exists mainly in specifications with limited practical deployment, focusing on NR as the primary cell.