Method for supporting handover and corresponding apparatus

Abstract

The present disclosure relates to a communication method and system for converging a 5 th -Generation (5G) communication system for supporting higher data rates beyond a 4 th -Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The present application provides a method of a base station for supporting an inter-system handover from an evolved packet system (EPS) system to a 5th generation (5G) system. Disclosed methods solve the data forwarding problem during the movement of a UE between an LTE system and a 5G system, so that the loss of data is avoided and the continuity of services is ensured.

What is claimed is: 
     
         1 . A method performed by a base station associated with a first radio access technology (RAT) in a wireless communication system, the method comprising:
 determining to handover UE to a second RAT;   transmitting, to an Access and Mobility Management Function (AMF), a handover required message including a source to target transparent container;   receiving, from the AMF, a handover command message; and   transmitting, to a user equipment (UE), the handover command message.   
     
     
         2 . The method according to  claim 1 , wherein the source to target transparent container includes an E-UTRAN Radio Access Bearer (E-RAB) identifier and data forwarding information. 
     
     
         3 . The method according to  claim 1 ,
 wherein the handover command message includes Evolved Packet System (EPS) Bearer identifiers, and   wherein ongoing Quality of Service (QoS) Flows with the EPS Bearer identifiers is correlated by the UE.   
     
     
         4 . The method according to  claim 1 , wherein the handover command message includes tunnel information for data forwarding. 
     
     
         5 . The method according to  claim 1 , wherein the first RAT is associated with 5th generation core (5GC), and the second RAT is associated with Evolved Packet Core (EPC). 
     
     
         6 . A method performed by an Access and Mobility Management Function (AMF) in a wireless communication system, the method comprising:
 receiving, from a base station associated with a first radio access technology (RAT), a handover required message including a source to target transparent container;   selecting a mobile management entity (MME) based on the handover Required message;   transmitting, to the MME, a relocation request message;   receiving, from the MME, a relocation response message including a target to source transparent container; and   transmitting, to the base station, a handover command.   
     
     
         7 . The method according to  claim 5 , wherein the source to target transparent container includes an E-UTRAN Radio Access Bearer (E-RAB) identifier and data forwarding information. 
     
     
         8 . The method according to  claim 5 ,
 wherein the handover command includes Evolved Packet System (EPS) Bearer identifiers, and   wherein ongoing Quality of Service (QoS) Flows with the EPS Bearer identifiers is correlated by the UE.   
     
     
         9 . The method according to  claim 5 , wherein the handover command includes tunnel information for data forwarding. 
     
     
         10 . The method according to  claim 5 , wherein the first RAT is associated with 5th generation core (5GC). 
     
     
         11 . A base station associated with a first radio access technology (RAT) in a wireless communication system, the base station comprising:
 a transceiver; and   a controller coupled with the transceiver and configured to:
 determine, to handover UE to a second RAT; 
 transmit, to an Access and Mobility Management Function (AMF), a handover required message including a Source to Target Transparent Container; 
 receive, from the AMF, a handover command message; and 
 transmit, to a user equipment (UE), the handover command message. 
   
     
     
         12 . The base station according to  claim 11 , wherein the source to target transparent container includes an E-UTRAN Radio Access Bearer (E-RAB) identifier and data forwarding information. 
     
     
         13 . The base station according to  claim 11 ,
 wherein the handover command message includes Evolved Packet System (EPS) Bearer identifiers, and   wherein ongoing Quality of Service (QoS) Flows with the EPS Bearer identifiers is correlated by the UE.   
     
     
         14 . The base station according to  claim 11 , wherein the handover command message includes tunnel information for data forwarding. 
     
     
         15 . The base station according to  claim 11 , wherein the first RAT is associated with generation core (5GC), and the second RAT is associated with Evolved Packet Core (EPC). 
     
     
         16 . An Access and Mobility Management Function (AMF) in a wireless communication system, the AMF comprising:
 a transceiver; and   a controller coupled with the transceiver and configured to:
 receive, from a base station associated with a first radio access technology (RAT), a handover required message including a source to target transparent container; 
 select a mobile management entity (MME) based on the handover Required message; 
 transmit, to the MME, a relocation request message; 
 receive, from the MME, a relocation response message including a target to source transparent container; and 
 transmit, to the base station, a handover command. 
   
     
     
         17 . The AMF according to  claim 15 , wherein the source to target transparent container includes an E-UTRAN Radio Access Bearer (E-RAB) identifier and data forwarding information. 
     
     
         18 . The AMF according to  claim 15 ,
 wherein the handover command includes Evolved Packet System (EPS) Bearer identifiers, and   wherein ongoing Quality of Service (QoS) Flows with the EPS Bearer identifiers is correlated by the UE.   
     
     
         19 . The AMF according to  claim 15 , wherein the handover command includes tunnel information for data forwarding. 
     
     
         20 . The AMF according to  claim 15 , wherein the first RAT is associated with 5th generation core (5GC).