Let’s examine the X2 Handover in detail. We look at the X2 handover signaling procedure through sequence diagrams that focus on different aspects of the procedure.
The sequence diagrams presented here were generated with EventStudio System Designer.
LTE X2 Handover
Full signaling details are presented here.
Now we examine the same flow at a higher level of abstraction. The diagram focuses on the interactions between the mobile, eNodeBs and the MME/SGW.
We now explore the signaling procedures that involve the UE.
Source eNodeB Role
Examine the interactions that involve the eNodeB that initiated the handover.
Target eNodeB Role
We now look at the interactions involving the eNodeB that will be serving the UE after the handover.
RRC Signaling the X2 Handover
The Radio Resource Control (RRC) signaling between the UE and the eNodeBs is covered here.
X2AP Signaling Between eNodeBs
X2AP is used for signaling between the eNodeBs. Here we examine the X2AP interactions.
Data Path Changes During an X2 Handover
The data path switching goes through several steps to accomplish a seamless handover.