UMTS LTE X2 Interfaces

What does LTE X2 connectivity mean?
LTE X2 connection, X2AP, X2U, eNB.

LTE X2 connections : This defines interface between two E-UTRAN NodeB’s (eNB’s). This interface can support both data X2U and control X2AP. In some scenarios only X2AP interface is implemented and others only X2U interface.
An important technical detail to understand for X2 connection is the logical nature of the interface.
In most architecture’s its shown as a direct connection between eNodeB’s. For implementations, its physically routed through transport connections similar to S1 interface connections. The LTE connection’s between eNB’s S1 and X2 are shown in diagram below.

LTE - 4G Wireless Technology

Digital fundamentals.

Interview Questions.

LTE UMTs X2 interface.

UMTS LTE X2 and S1 interface, Diagram above to discuss S1 and X2 interfaces
LTE X2 interface Functionality :
(1) Mobility Management.
(2) Enable Inter-Cell interference and Load Management .
(3) SON (discussed below) and automatic neighbor relations management
(4) Set/Reset X2 interface.
(5) Error Handling for specific or general cases.

X2 contd.

UMTS LTE X2 contd. - SON, X2AP, X2U & eNB

SON is Self Optimizing Network.

A self optimizing function would increase network performance and quality by reacting to dynamic processes in the network. These operations minimizes the operational overhead by self-configuring and self -optimization.

eNB or eNodeB -

eNB interfaces with the mobile and is responsible for hosting and managing following interfaces.

Physical channels,
Medium Access Control (MAC),
Radio Link Control (RLC),
Packet Data Control Protocol (PDCP) layers.
Radio Resource Control (RRC) in control plane.

Also manages many functions related to :-
Radio resource management,
Admission control,
Enforcement of negotiated UL QoS,
Cell information broadcast,
Ciphering /deciphering of user and control plane data,
Compression /decompression of DL/UL user plane packet headers.


Verilog Tutorial.

LTE Tutorial.

Memory Tutorial.

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