User's Manual

Ver.
CHAPTER 4. Message Flow
2600-00FKQFGA2
1.0
LTE Handover: S1-based Handover
The message flow for S1 based handover procedure is illustrated below.
Figure 21. S1-based Handover Procedure
UE
Source Indoor
Pico Cell
MME
S-GW
EPC
Target Indoor
Pico Cell
Downlink/Uplink data
Downlink/Uplink data
3) HANDOVER REQUEST
5) Create Indirect Data
Forwarding Tunnel Request
8) RRCConnection-
Reconfiguration
(mobilityControlinfo)
1) Direct data forwarding
1) Decision to trigger a relocation via S1
2) HANDOVER REQUIRED
Indirect data forwarding
Downlink data
Downlink data
End marker
End marker
6) Create Indirect Data
Forwarding Tunnel Response
7) HANDOVER COMMAND
9) eNB STATUS TRANSFER
10) MME STATUS TRANSFER
2) Indirect data forwarding
11) Detach from old cell/Synchronize to new cell
12) RRCConnectionReconfigurationComplete
Forwarded data
Uplink data
Uplink data
13) HANDOVER NOTIFY
14) Modify Bearer Request
15) Modify Bearer Response
Forwarded data
16) Tracking Area Update procedure
17) UE CONTEXT RELEASE COMMAND
18) UE CONTEXT RELEASE COMPLETE
19) Delete Indirect Data
Forwarding Tunnel Request
20) Delete Indirect Data
Forwarding Tunnel Response
Downlink/Uplink data
Downlink/Uplink data
4) HANDOVER REQUEST
ACKNOWLEDGE
© SAMSUNG Electronics Co., Ltd.
page 57 of 72