1. IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-10-0114-01-srho
Title: Comments and Questions for Optimized Single Radio Handover Procedures of WMF
Date Submitted: June 2, 2010
Presented at IEEE
Authors or Source(s):
Yoon-Young An, Junghoon Jee, Hongseok Jeon, Changmin Park, Byungjun Ahn (ETRI)
Abstract: Comments and Questions for Optimized Single Radio Handover Procedures of WMF

2. IEEE 802.21 presentation release statements
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The contributor is familiar with IEEE patent policy, as stated in Section 6 of the IEEE-SA Standards Board bylaws < and in Understanding Patent Issues During IEEE Standards Development
IEEE presentation release statements
This document has been prepared to assist the IEEE Working Group. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE
The contributor is familiar with IEEE patent policy, as outlined in Section 6.3 of the IEEE-SA Standards Board Operations Manual < and in Understanding Patent Issues During IEEE Standards Development

3. Optimized Single Radio Handover Key Features

4. Pre-Registration over L3 tunnel
E.g., WiMAX SFF (Signaling Forwarding Function) performs target BS (Base Station) operations while the MS is located in non-WiMAX Access network
MAC messages transfer over L3 tunnel
Pre-registration toward target WiMAX network
IP Core Network
Data
ASN-GW
WiMAX SFF AR
Pre-registration through L3 tunnel BS
(Target)
Serving AP BS
(Another Candidate)

5. Review of Detailed Procedures
- WiMAX IWK case

6. Overall Steps
Note: Figure from DCN and clarification is marked as blue

7. Phase-1: SR Target Network Detection and WiMAX SFF Discovery
Note: Figure from DCN and
the Information Service query is added by referencing DCN

8. Comments for Phase 1
Complete network discovery phase is not specified in 3G IWK document
SFF Discovery
+ Information of available access networks, Information about interworking and roaming aspects
The DHCP and DNS procedures for “SFF IP address discovery” are not required in case where Information Server provides SFF IP address to MS through MIH_Information_Response as per DCN

9. Phase-2: SR Handover Session Pre-Registration (1)
Current MN/WiMAX State: Idle or Null State
Assumption
ASN-GW for WiMAX SFF  Pre-registered ASN-GW
Pre-registered ASN-GW includes Authenticator MN
IP Core Network
WiMAX
SFF
Target
BS/ASN-GW
Pre-registered ASN-GW
Anchored ASN-GW HA
Information Server
AAA
WiFi
WiMAX AP
Data
IKEv2 procedure to setup a secure tunnel
Phase2
secure tunnel
WIMAX SFF starts to perform BS operation
DCD/UCD & BSID
Initial Network Entry Procedure (stage )
MS-to-Network
EAP authentication
Process +
MS e
registration
MS-to-Network EAP authentication process
REG_REQ
MS_Attachment_Req
MS_Attachment_Rsp
REG_RSP
MS_Attachment_Ack
Connections Establishment
Data Path Establishment

10. Phase-2: SR Handover Session Active mode HO Preparation (2)
Current WiMAX State : Pseudo Active State
Assumption
Pre-registered ASN-GW includes Authenticator
Apply ASN Anchored Mobility (WiMAX stage3 4.7 ASN Anchored Mobility) MN
IP Core Network
WiMAX
SFF
Target
BS/ASN-GW
Pre-registered ASN-GW
Anchored ASN-GW HA
Information Server
AAA
WiFi
WiMAX AP
MOB_MSHO_Req
Active mode HO Preparation Procedure
• Successful HO Preparation Phase (stage )
HO_Req
HO_Req
This message have target BS’s information
Context retrieve
If Serving ASN is co-located with the authenticator ASN,
no Authenticator ID TLV
DP Pre-Reg.
HO_Rsp
HO_Rsp
MOB_BSHO_Rsp
HO_Ack
HO_Ack
MOB_MSHO_Ind
• Successful HO Action Phase (stage )
HO_Cnf
HO_Cnf
HO_Ack
HO_Ack

11. Comments for Phase 2 Active Mode HO Preparation is triggered by MS
MS sends MOB_MSHO_Req message to SFF
Does SFF trigger Active Mode HO Preparation to sends MOB_BSHO_Req message.
At that time, what can Information server do?
During Active Mode HO Preparation procedure, suddenly WiFi link is disconnected.
WiMAX interface of MS will perform the normal attachment procedure.
We have to consider the reactive mode process.

12. Phase-3: SR Handover Action
Assumption
Pre-registered ASN-GW includes Authenticator
Apply ASN Anchored Mobility (WiMAX stage3 4.7 ASN Anchored Mobility) MN
IP Core Network
WiMAX
SFF
Target
BS/ASN-GW
Pre-registered ASN-GW
Anchored ASN-GW HA
Information Server
AAA
WiFi
WiMAX AP
Network ReEntry
DP Pre-Reg. Procedure
PBU
• Successful
HO Action
Phase
(stage3 )
PBA
CMAC Key Count Update
HO_Complete
HO_Complete
HO_Ack
HO_Ack
Current State  Active State
Data Path
Deregistration
Data

13. Clarifying Questions for Phase 2 and 3(1)
Which steps are included for “Pre-Registration”?
1) Initial Network Entry
2) Initial Network Entry
+ HO Procedures (up to MOB_HO-IND)
ASN-GW clarification in the figure of Slide #6?
1) Pre-registered ASN-GW?
2) Anchor ASN-GW?
3) Target ASN-GW (for Target BS)?
4) ASN-GW of WiMAX SFF?
Which entity manages the pre-registered contexts?
1) SFF or
2) ASN-GW

14. Clarifying Questions for Phase 2 and 3(2)
WiMAX forum applied ASN anchored mobility(state 3 4.7) to single radio inter-RAT HO procedures
Inter-RAT HO needs IP mobility(MIP, PMIP).
CSN anchored mobility has IP mobility function.