5G X2/Xn Interface Between RAN Nodes

  • The X2 interface is used for communication between RAN nodes in non-standalone operation, such as between eNBs in LTE and between en-gNBs and eNBs in 5G.

  • The Xn interface is a new interface specified for communication between RAN nodes in standalone operation, such as between ng-eNBs and gNBs.

  • The extensions of X2 include functions for EN-DC (Evolved NodeB – Dual Connectivity) and flow control for split bearers in non-standalone operation.

  • X2 interface is used between eNBs in LTE and between RAN nodes in non-standalone operation (between eNB and en‒gNB).

  • Xn interface is newly specified between RAN nodes in standalone operation (between ng‒eNB and ng‒eNB/gNB and gNB/ng‒eNB and gNB).

  • Extensions of X2 include functions adopting EN-DC and flow control for split bearers for non-standalone operation
    Flow control function, which was defined for LTE-DC split bearers in Release 12, is used to split downlink data when using radio resources of multiple RAN nodes.

  • Xn is based on the X2 function but with enhanced UE context management function for adopting new QoS flow framework and network slice.

Credits: :point_down:

The 5G interface that connects two gNodeBs (next-gen base stations) :satellite::satellite: is known as the Xn interface. It plays a crucial role in ensuring seamless connectivity and mobility :signal_strength::man_running: for users in the network.

:link: Xn Interface

:handshake: Mobility Management: When a user moves from one gNodeB coverage area to another, the Xn interface helps in smooth handovers :arrows_counterclockwise:, maintaining uninterrupted data sessions :computer::iphone:.

For example, when you’re on a video call :video_camera::telephone_receiver: while traveling in a car :red_car:, the Xn interface helps maintain the call quality as you move between different gNodeB coverage areas.

:arrows_counterclockwise: Load Balancing: If one gNodeB :satellite: is handling too much traffic :vertical_traffic_light:, the Xn interface enables it to share the load with a neighboring gNodeB :satellite:, ensuring optimal performance :rocket:. Imagine a crowded concert :microphone::guitar: with many people using their phones :iphone:. The Xn interface helps distribute the network load :balance_scale: among multiple gNodeBs, preventing congestion :construction:.

:performing_arts: Interference Coordination: The Xn interface aids in reducing signal interference :chart_with_downwards_trend: by coordinating transmission parameters :gear: between gNodeBs. For example, when two gNodeBs :satellite::satellite: are transmitting signals :signal_strength: in the same frequency band, the Xn interface helps prevent interference :no_entry_sign: by adjusting their transmission power :bulb: and other parameters.

:globe_with_meridians: Dual-Connectivity: The Xn interface allows a user device to connect simultaneously to two gNodeBs :satellite::satellite:, improving network performance :star2:. For instance, during a large file download :open_file_folder::calling:, dual-connectivity can boost download speeds :bullettrain_side: by utilizing resources from both gNodeBs…

In summary, the Xn interface is a critical component in 5G networks, connecting two gNodeBs :satellite::satellite: and ensuring seamless connectivity :signal_strength:, mobility :man_running:, and optimal network performance :rocket: for users.

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