ABSTRACT: This contribution introduces the inter-RAT fast handover solution. TITLE: Inter-Radio Access Technology Fast Handover TSG-A WG4 RECOMMENDATION: FYI Samsung Electronics grant a free, irrevocable license to 3GPP2 and its Organizational Partners to incorporate text or other copyrightable material contained in the contribution and any modifications thereof in the creation of 3GPP2 publications; to copyright and sell in Organizational Partner's name any Organizational Partner's standards publication even though it may include all or portions of this contribution; and at the Organizational Partner's sole discretion to permit others to reproduce in whole or in part such contribution or the resulting Organizational Partner's standards publication. Samsung Electronics are also willing to grant licenses under such contributor copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing an Organizational Partner’s standard which incorporates this contribution. This document has been prepared by Samsung Electronics to assist the development of specifications by 3GPP2. It is proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on Samsung Electronics. Samsung Electronics specifically reserves the right to amend or modify the material contained herein and to any intellectual property of Samsung Electronics other than provided in the copyright statement above. DATE: August 27, 2007 Notice SOURCE: Samsung : BeomSik Bae, Bill Semper Tel

1 Principles Single radio operation –Dual radio operation should be supported, but not mentioned in this material. Bi-directional fast handover Minimum change of legacy system Common Solution for each scenario –DO-UMB –DO/UMB-LTE –DO/UMB-WiMAX Low complexity of terminal

2 Overall issues for Inter-RAT handover System measurement (if needed) –Target system information –Measurement report –Handover decision/initiation Target system preparation –Method Tunneling based –Steps MS capability negotiation Authentication Session Setup Radio Resource reservation Layer 3 path switch Handover trigger –Handover trigger –Target system access –Resource removal from source system MSBSAGWT-BST-AGW 1. System measurement 2. Measurement Report 3. Handover decision 4. Target system preparation - MS capability - Authentication - Session setup - Radio Resource reservation - Layer 3 path switch 5. Handover trigger (if needed) 6. Target system access 7. source system resource release HA Scope of TSG-C if needed

3 Tunneling approach Layer 3 tunneling based approach –MS can use the IP connectivity for communicating with the target system. –MS should be aware of IP address of the target system node and a tunneling protocol over IP layer should be defined between the MS and the target node. –A IWU can be introduced as the termination point of the tunneling which has the AN functionality of the target system and is connected to the CN node (e.g., 3GPP SAE S-GW and WiMAX ASN-GW) –Minimum change of the source system nodes (e.g., DO AN/PCF/PDSN, and UMB eBS/AGW) is required. No change can be achieved, but minimum change can be considered to improve the efficiency. –IETF protocol can be used with minimal modification for tunneling or new tunneling protocol can be designed.

Tunneling approach examples [1] UMB to DO

Tunneling approach examples [2] DO to UMB

Tunneling approach examples [3] DO to 3GPP LTE

Tunneling approach examples [4] DO to WiMAX

8 Layer 3 tunneling solution design [1] Architecture –IWU (Broker) either has RAN functionality or RAN functionality and also CN functionality With DO as the target system –AN and PCF functionality having A10/A11 and A13 interfaces with PDSN and PCF –AN functionality having A8/A9/(A14)/(A20) interface with PCF (legacy AN upgrade) With UMB as the target system (FFS) –eBS functionality having U1, U2, and U3 interfaces with AGW, SRNC and eBS respectively With 3GPP LTE as the target system –eBS and MME functionalities having S10 and S11 interfaces with MME and Serving GW respectively –eBS functionality having S1 interface with MME With WiMAX as the target system –BS and ASN-GW functionality having R4 interface with other ASN-GW –BS functionality having R6 interface with ASN-GW

9 Layer 3 tunneling solution design [2] Handover flow for handover from DO to UMB 1.HO is triggered based on the radio link condition or based on the system information 2.MS discovers the IP address of IWU 3.MS is authenticated by IWU for L3 tunneling (if needed) 4.MS communicates with UMB system via IWU. MS authentication and session negotiation are performed 5.HO decision can be made by MS or network based on the radio link condition or based on some policy 6.IWU may trigger the inter-eBS hard handoff 7.MS accesses UMB eBS MS AN SRNC PCF PDSN UMB DO AGW Route Open Authentication HO Indication L3 Tunnel Data service over UMB IWU IWU Discovery L3 Tunnel MS Authentication by IWU (if needed) HO Decision L3 Tunnel Data service over DO Session Negotiation HO Trigger eBS Radio Resource reservation (if needed) UMB Air access

10 Layer 3 tunneling solution design [3] Handover flow for handover from DO to 3GPP LTE 1.HO is triggered based on the radio link condition or based on the system information 2.MS discovers the IP address of IWU 3.MS is authenticated by IWU for L3 tunneling (if needed) 4.MS communicates with LTE system via IWU. MS capability negotiation, authentication and LTE session setup are performed 5.HO decision can be made by MS or network based on the radio link condition or based on some policy 6.IWU may trigger the handoff 7.MS accesses LTE eNB MS AN MME PCF PDSN LTE DO S-GW MS capability negotiation Authentication HO Indication L3 Tunnel Data service over LTE IWU IWU Discovery L3 Tunnel MS Authentication by IWU (if needed) HO Decision L3 Tunnel Data service over DO Session Setup HO Trigger eNB LTE Air access Radio Resource reservation (if needed)

11 Layer 3 tunneling solution design [4] Handover flow for handover from DO to WiMAX 1.HO is triggered based on the radio link condition or based on the system information 2.MS discovers the IP address of IWU 3.MS is authenticated by IWU for L3 tunneling (if needed) 4.MS communicates with WiMAX system via IWU. MS capability negotiation, authentication and WiMAX session setup are performed 5.HO decision can be made by MS or network based on the radio link condition or based on some policy 6.IWU may trigger the handoff 7.MS accesses WiMAX BS MS AN ASN-GW PCF PDSN WiMAX DO WiMAX BS MS capability Authentication HO Indication L3 Tunnel Data service over WiMAX IWU IWU Discovery L3 Tunnel MS Authentication by IWU (if needed) HO Decision L3 Tunnel Radio Resource reservation (if needed) WIMAX Air access Data service over DO WiMAX Session Setup HO Trigger

12 Layer 3 tunneling solution design [5] Study area –When IWU discovery is triggered –Mechanism to get the IP address of IWU –Authentication mechanism for IWU –L3 tunneling protocol between UE and IWU –Separation of IWU from BS –When CMIP/PMIP BU should be triggered UE eNB ASN-GW MME PDN-GWServing-GW WiMAX LTE BS UE capability Authentication HO Indication L3 Tunnel Data service over DO IWU IWU Discovery L3 Tunnel UE Authentication by IWU HO Decision L3 Tunnel Radio Resource reservation WiMAX Air access (Inter BS handover) Data service over LTE Session setup HO Trigger

13 Analysis of layer 3 tunneling based approach Layer 3 tunneling based approach does not need the change of the source system –By introducing a new layer 3 node (which is called IWU in the previous slide), inter-RAT mobility can be supported without requiring any change of source system –Only tunneling protocol is newly introduced, so simple. –Optimized handover from legacy system to the non-3GPP system also can be supported without impact to the legacy system. –Layer 3 tunneling solution can be the common solution for support any inter-RAT handover (e.g. DO-UMB, DO/UMB-3GPP LTE, DO/UMB-WiMAX)