1. IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-05-0566-00-0000
Title: Proposal for Handover Procedures of
Date Submitted: February, 17, 2006
Presented at IEEE session #13 in Denver
Authors or Source(s):
 Liuyuan, Zhonghui, Wangshu
Abstract: This proposal gives the drawing of handover flow and the handover description of It uses the handover from to 3GPP as an example to illustrate the handover procedures initiated by terminal and network. .

2. IEEE 802.21 presentation release statements
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3. Handover Procedure Initiated by Terminal
The STA/UE is currently associated with an PoA and has an session established with the Home Agent.
When the radio conditions have became undesirable because of signal attenuation or the other reasons, the MIH Function is notified through the Link_Going_Down or Link_Parameters_Change trigger by the interface in the STA/UE and MIH Function notifies the MIH User through the corresponding MIH_Link_Going_Down or MIH_Link_Parameters_Report event. These notifications can also be gotten from the network side (The STA/UE has previously registered for the event services in the network) and this is illustrated with the dotted arrow lines.
The MIH User at the STA/UE sends MIH_Capability_Discover request to query the available PoAs with MIH capabilities and gets the response through the current connection. This can be finished optionally by sending MIH_Capability_Discover to the MIH Information Server.
By Sending MIH_Get_Information request, MIH User at the STA/UE can get information about the PoAs those have sent MIH_Capability_Discover responses to the STA/UE. The information can help handover strategy engine to make handover decisions.
The MIH User at the STA/UE selects a suggested PoA based on the information received from the responses of MIH_Capability_Discover and MIH_Get_Information for the handover preparation. This is not in the sope of

4. Handover Procedure Initiated by Terminal
The MIH User generates a MIH_Handover_Initiate request to its local MIH Function and the local MIH Function relays the message to its peer at the current PoA in the network. This message contains the information of the suggested PoA selected by the STA/UE.
After receiving the MIH_Handover_Initiate request message, the MIH Function at the PoA may generate a MIH_Handover_Prepare request to the peer at the new PoA suggested by STA/UE for resource reservation.
The MIH Function at the PoA of the current connection selects the preferred PoA based on the response of the primitive MIH_Handover_Prepared from the new PoA. This select procedure is out of the sope of
The MIH Function of the current PoA sends MIH_Handover_Initiate response to its peer at the STA/UE. The response contains the information of the preferred PoA.
The MIH User at the STA/UE generates a MIH_Switch request for a new connection.
The MIH User at the STA/UE sends a MIH_Handover_Commit request for the beginning of the handover commitment and receives the MIH_Handover_Commit response from the new PoA that indicates the handover is going to be executed.

5. Handover Procedure Initiated by Terminal
The MIH Function and the MIH User at the STA/UE may be notified through the Link_Handover_Imminent and MIH_Link_Handover_Imminent indications when the the new link connection begins. This can also be done by the MIH Function of the network.
The new link connection with the PoA of 3GPP is enstablished.
The MIH Function and the MIH User at the STA/UE may receive the Link_Up and MIH_Link_Up indications when the L2 connection is enstablished. This can also be done by the MIH Function of the network.
The registration of Mobil IP might be now trigger.
The MIH Function at the new PoA may send a MIH_Handover_Complete request to the peer at the old PoA. The receiving MIH Function can forward the remaining packets and release the resources in use by the old link.
The Link_Down and MIH_Link_Down events may be sent to the local MIH Function and MIH User to indicate that the old link with is down. This can also be done by the MIH Function of the network.

6. Handover Procedure Initiated by Terminal
After the handover completion, the MIH Function and the MIH User at the STA/UE may receive the Link_Handover_Complete and MIH_Link_Handover_Complete indications. This can also be done by the MIH Function of the network.
The MIH User receives the MIH_Switch response that indicates the completion of the handover.
The current session is now transferred toward the new link layer.
The STA/UE is disassociated from the previous PoA.

7. 21-05-0566-00-0000 PoA2(3GPP) HA FA MIH Information Server Other MIH
Network
Elements
STA/UE
Client
User
Function
802.11
3GPP
PoA1(802.11)
LLC/MAC/PHY
GERAN/
UMTS/LTE
Current Connection 1
Associated
Link_Going_Down.indication/Link_Parameters_Change.indication 2
MIH_Link_Going_Down.indication/MIH_Link_Parameters_Report.indication
MIH_Capability_Discover.request 3
MIH_Capability_Discover.response
MIH_Get_Information.request 4
MIH_Get_Information.response
Select
Suggested PoA 5
MIH_Handover_Initiate.request 6
MIH_Handover_Prepare.request 7
MIH_Handover_Prepare.response 8
Select
Preferred PoA
MIH_Handover_Initiate.reponse 9
MIH_Switch.request 10

8. Bearer Connection over 3GPP
PoA2(3GPP) HA FA
MIH
Information
Server
Other MIH
Network
Elements
STA/UE
Client
User
Function
802.11
3GPP
PoA1(802.11)
LLC/MAC/PHY
GERAN/
UMTS/LTE
MIH_Handover_Commit.request 11
MIH_Handover_Commit.response
Link_Handover_Imminent.indication
Link_Handover_Imminent.indication 12
MIH_Link_Handover_Imminent.indication 13
3GPP Link Establishment
Link_Up.indication
Link_Up.indication 14
MIH_Link_Up.indication
MIP Registration 15
MIH_Handover_Complete.request 16
MIH_Handover_Complete.response
Link_Down.indication
Link_Down.indication 17
Link_Down.indication
Link_Handover_Complete.indication
Link_Handover_Complete.indication 18
MIH_Link_Handover_Complete.indication 19
MIH_Switch.response 20
Bearer Connection over 3GPP 21
Dissassociated

9. Handover Procedure Initiated by Network
The STA/UE is currently associated with an PoA and has an session established with the Home Agent.
When the radio conditions have became undesirable because of signal attenuation or the other reasons, the MIH Function at the PoA is notified through the Link_Going_Down or Link_Parameters_Change trigger and MIH Function notifies the MIH User through the corresponding MIH_Link_Going_Down or MIH_Link_Parameters_Report event. These notifications can also be gotten from the STA/UE (The relevant events have been previously registered at the STA/UE) and this is illustrated with the dotted arrow lines.
The MIH User at the PoA sends MIH_Capability_Discover request to query the available PoAs with MIH capabilities in the network and gets the corresponding response. This can be finished optionally by sending MIH_Capability_Discover to the MIH Information Server.
By Sending MIH_Get_Information request, MIH User at the PoA can get information about the PoAs those have sent MIH_Capability_Discover responses. The information can help handover strategy engine to make handover decisions.
The MIH User at the PoA selects a suggested PoA based on the information received from the responses of MIH_Capability_Discover and MIH_Get_Information for the handover preparation. This is not in the sope of

10. Handover Procedure Initiated by Network
The MIH User at the PoA generates a MIH_Handover_Initiate request to its local MIH Function and the local MIH Function relays the message to its peer at the STA/UE. This message contains the information of the suggested PoA selected by the current PoA.
The MIH Function at the STA/UE selects the preferred PoA based on the response of the primitive MIH_Handover_Prepared from the current PoA. This select procedure is out of the sope of
The MIH Function of the STA/UE sends MIH_Handover_Initiate response to its peer at the current PoA. The response contains the information of the preferred PoA.
After receiving the MIH_Handover_Initiate response message, the MIH Function at the current PoA may generate a MIH_Handover_Prepare request to the peer at the new PoA suggested by STA/UE for resource reservation.
The MIH User at the STA/UE generates a MIH_Switch request for a new connection.
The MIH User at the new PoA sends a MIH_Handover_Commit request for the beginning of the handover commitment and receives the MIH_Handover_Commit response from the STA/UE that indicates the handover is going to be executed.

11. Handover Procedure Initiated by Network
The MIH Function and the MIH User at the new PoA may be notified through the Link_Handover_Imminent and MIH_Link_Handover_Imminent indications when the execution of the new link connection is imminent. This can also be done by the MIH Function of the STA/UE.
The new link connection with the PoA of 3GPP is enstablished.
The MIH Function and the MIH User at the new PoA may receive the Link_Up and MIH_Link_Up indications when the L2 connection is enstablished. This can also be done by the MIH Function of the STA/UE.
The registration of Mobil IP might be now trigger.
The MIH Function at the new PoA may send a MIH_Handover_Complete request to the peer at the old PoA. The receiving MIH Function can forward the remaining packets and release the resources in use by the old link.
The Link_Down and MIH_Link_Down events may be sent to the MIH Function and MIH User at the old PoA to indicate that the old link with is down. This can also be done by the MIH Function of STA/UE.
After the handover completion, the MIH Function and the MIH User at the new PoA may receive the Link_Handover_Complete and MIH_Link_Handover_Complete indications. This can also be done by the MIH Function of the STA/UE.

12. Handover Procedure Initiated by Network
The MIH User receives the MIH_Switch response that indicates the completion of the handover.
The current session is now transferred toward the new link layer.
The STA/UE is disassociated from the previous PoA.

13. 21-05-0566-00-0000 PoA2(3GPP) HA FA MIH Information Server Other MIH
Network
Elements
STA/UE
Client
User
Function
802.11
3GPP
PoA1(802.11)
LLC/MAC/PHY
GERAN/
UMTS/LTE
Current Connection 1
Associated
Link_Going_Down.indication/Link_Parameters_Change.indication 2
MIH_Link_Going_Down.indication/MIH_Link_Parameters_Report.indication
MIH_Capability_Discover.request 3
MIH_Capability_Discover.response
MIH_Get_Information.request 4
MIH_Get_Information.response
Select
Suggested PoA 5
MIH_Handover_Initiate.request 6
Select
Preferred PoA 7
MIH_Handover_Initiate.reponse 8
MIH_Handover_Prepare.request 9
MIH_Handover_Prepare.response 10
MIH_Switch.request

14. Bearer Connection over 3GPP
PoA2(3GPP) HA FA
MIH
Information
Server
Other MIH
Network
Elements
STA/UE
Client
User
Function
802.11
3GPP
PoA1(802.11)
LLC/MAC/PHY
GERAN/
UMTS/LTE
MIH_Handover_Commit.request 11
MIH_Handover_Commit.response
Link_Handover_Imminent.indication
Link_Handover_Imminent.indication 12
MIH_Link_Handover_Imminent.indication
3GPP Link Establishment 13
Link_Up.indication
Link_Up.indication 14
MIH_Link_Up.indication
MIP Registration 15
MIH_Handover_Complete.request 16
MIH_Handover_Complete.response
Link_Down.indication
Link_Down.indication 17
Link_Down.indication
Link_Handover_Complete.indication
Link_Handover_Complete.indication 18
MIH_Link_Handover_Complete.indication 19
MIH_Switch.response 20
Bearer Connection over 3GPP 21
Dissassociated