Wireless access network node, wireless terminal, core network node and method thereof

Abstract

Provided are a wireless access network node, a wireless terminal, a core network node and a method thereof. A target RAN node is configured to connect to a core network associated with a PDU session-based network and perform signaling related to a handover of the wireless terminal from a source RAN node to a target RAN node, the source RAN node and the target RAN node are connected to the same core network, the target RAN node comprises: a memory; and a processor connected to the memory, the processor being configured to: receive a handover request message requesting handover from the core network, the handover request message comprising flow information related to at least one PDU session to be established, the flow information comprising a flow identifier and a flow QoS parameter for each flow of the PDU session; and in response to the handover request message, send a handover request confirmation message to the core network.

Description

[0001] This application is a divisional application of an invention patent application with application date of May 16, 2017, application number 201780062412.X, and titled “Wireless access network node, wireless terminal and method thereof”. Technical Field

[0002] The present invention relates to a wireless communication system, and in particular, to a handover of a wireless terminal between different radio access technologies (RATs). Background Art

[0003] The 3rd Generation Partnership Project (3GPP) began working on the standardization of the fifth generation mobile communication system (5G) in 2016 (i.e., 3GPP Release 14) to make 5G a commercial reality in 2020 (see Non-Patent Literature 1). 5G is expected to be achieved through the continued enhancement / evolution of LTE and Advanced LTE and through the introduction of innovative enhancement / evolution of new 5G air interfaces (i.e., new radio access technologies (RATs)). The new RAT supports, for example, higher frequency bands than those supported by LTE / Advanced LTE and its continued evolution (e.g., below 6 GHz). For example, the new RAT supports centimeter wave bands (above 10 GHz) and millimeter wave bands (above 30 GHz).

[0004] In this specification, the fifth generation mobile communication system is also referred to as the next generation (NextGen) system (NG system). The new RAT of the NG system is called new radio (NR), 5G RAT or NG RAT. The new radio access network (RAN) and core network of the NG system are respectively referred to as NextGen RAN (NG RAN) and NextGen core (NG core). The wireless terminal (ie, user equipment (UE)) connected to the NG system is called NextGen UE (NG UE). As standardization work progresses, the official names of RAT, UE, radio access network, core network, network entity (or node), protocol layer, etc. of the NG system will be determined in the future.

[0005] Unless otherwise specified, the term "LTE" used in this specification includes enhancements / evolutions of LTE and Advanced LTE to provide interworking with NG systems. The enhancements / evolutions of LTE and Advanced LTE used for interworking with NG systems are also referred to as Advanced LTE Pro, LTE+, or enhanced LTE (eLTE). In addition, unless otherwise specified, the terms related to LTE networks and logical entities used in this specification (such as "Evolved Packet Core (EPC)", "Mobility Management Entity (MME)", "Serving Gateway (S-GW)", and "Packet Data Network (PDN) Gateway (P-GW)", etc.) include their enhancements / evolutions to provide interworking with NG systems. Enhanced EPC, enhanced MME, enhanced S-GW, and enhanced P-GW are also referred to as, for example, enhanced EPC (eEPC), enhanced MME (eMME), enhanced S-GW (eS-GW), and enhanced P-GW (eP-GW), respectively.

[0006] In LTE and LTE-Advanced, in order to achieve quality of service (QoS) and packet routing, bearers for each QoS level and for each PDN connection are used in both the RAN (i.e., Evolved Universal Terrestrial RAN) and the core network (i.e., Evolved Packet Core (EPC)). That is, in the bearer-based QoS (or QoS for each bearer) concept, one or more Evolved Packet System (EPS) bearers are configured between the UE and the P-GW in the EPC, and multiple service data flows (SDFs) with the same QoS level are transmitted via one EPS bearer that meets the QoS. SDF is one or more packet flows that match the SDF template (i.e., packet filter) based on the policy and charging control (PCC) rules. In addition, each packet to be sent via the EPS bearer used for packet routing contains information for identifying which bearer (i.e., General Packet Radio Service (GPRS) Tunneling Protocol (GTP) tunnel) the packet is associated with.

[0007] In contrast, with respect to the NG system, it has been suggested that although radio bearers can be used in the NG RAN, bearers are not used in the NG core or in the interface between the NG RAN and the NG core (see non-patent document 1). Specifically, a PDU flow is defined instead of the EPS bearer, and one or more SDFs are mapped to one or more PDU flows. The PDU flow between the NG UE and the user plane terminal entity in the NG core (i.e., the entity corresponding to the P-GW in the EPC) corresponds to the EPS bearer in the EPS bearer-based QoS concept. That is, instead of the bearer-based QoS concept, the NG system adopts the flow-based QoS (or QoS for each flow) concept. In the flow-based QoS concept, QoS is handled for each PDU flow. Note that the association between the UE and the data network is called a "PDU session". The term "PDU session" corresponds to the term "PDN connection" in LTE and Advanced LTE. Multiple PDU flows can be configured in one PDU session.

[0008] In this specification, a system (such as LTE and Advanced LTE systems, etc.) for configuring an end-to-end bearer (e.g., EPS bearer) between a UE and an edge node (e.g., P-GW) in a core network and adopting a bearer-based QoS concept is referred to as a "bearer-based system" or a "bearer-based network". In contrast, a system (such as an NG system, etc.) for not using any bearer in the core network or in the interface between the core network and the RAN and adopting a flow-based QoS concept is referred to as a "bearerless system" or a "bearerless network". Similar to the above-mentioned NG system, a radio bearer can be used in the RAN of a bearerless network. The term "bearerless" can also be expressed as, for example, no GTP, no (PDN) connection, no tunnel, (IP) flow-based, SDF-based, streaming media-based, or (PDU) session-based.

[0009] In addition, it has been suggested that NG systems support network slicing (see non-patent document 1). Network slicing uses network function virtualization (NFV) technology and software defined network (SDN) technology, and makes it possible to create multiple virtualized logical networks on a physical network. Each virtualized logical network is called a network slice or a network slice instance, includes logical nodes and functions, and is used for specific traffic and signaling. The NG RAN or the NG core or both have a slice selection function (SSF). The SSF selects one or more network slices suitable for the NGUE based on information provided by at least one of the NG UE and the NG core.

[0010] Patent document 1 discloses switching from a bearerless network (e.g., 5G) to a bearer-based network (e.g., LTE) and switching from a bearer-based network (e.g., LTE) to a bearerless network (e.g., 5G). In the switching from 5G to LTE disclosed in patent document 1, the source control node (i.e., access control server (ACS) / eMME) in the 5G core (or NG core) maps the QoS parameters of the service flow in the bearerless network (i.e., 5G) to the EPS bearer-level QoS in the bearer-based network (i.e., LTE). The QoS parameters of the service flow of 5G are, for example, DiffServ (Differentiated Services) Code Point (DSCP) values. The EPS bearer-level QoS in LTE is, for example, QoS Class Identifier (QCI) and Allocation and Retention Priority (ARP). The mapping of DSCP values ​​to EPS bearers can be performed in a one-to-one manner or in an n-to-one manner. The source ACS / eMME sends the APN information including information related to the EPS bearer-level QoS to the target MME. The target MME sets the GTP tunnel used by the UE based on the received APN information.

[0011] In addition, in the handover from LTE to 5G disclosed in Patent Document 1, the source MME in the LTE core (i.e., EPC) sends a forward relocation request containing the required bearer context information to the target ACS / eMME in the 5G core (NG core). The target ACS / eMME maps the QCI value received from LTE (i.e., the source MME) to the 5G QoS parameters (i.e., DSCP values) and supplies them to the transmission node (i.e., mobile gateway access router (M-GW / AR) or mobile gateway edge router (M-GW / ER)) in the 5G core (or NG core). By doing so, the target ACS / eMME sets up at least one generic routing encapsulation (GRE) tunnel for transmitting the UE's service flow (i.e., IP packets).

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: International Publication No. 2015 / 160329

[0015] Non-patent literature

[0016] Non-patent document 1: 3GPP TR 23.799 V0.6.0 (2016-07) “3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Study on Architecture for Next Generation System (Release 14)”, July 2016 Summary of the invention

[0017] Problem that the invention aims to solve

[0018] The inventors have studied the handover between a bearer-based network (e.g., LTE) and a bearer-free network (e.g., 5G), and found several problems. For example, Patent Document 1 discloses that in a handover from a bearer-based network (e.g., LTE) to a bearer-free network (e.g., 5G), the target ACS / eMME in the 5G core (NG core) maps the QCI value obtained from LTE (i.e., the source MME) to the 5G QoS parameter (i.e., DSCP value) and provides them to the transmission node (i.e., mobile gateway access router (M-GW / AR) or mobile gateway edge router (M-GW / ER)) in the 5G core (NG core). However, Patent Document 1 does not describe the details of the processing (especially the processing in the access layer (AS) layer) performed by the UE, the source eNodeB (eNB) in the E-UTRAN, and the target 5G access point (AP) in the 5G RAN (NG RAN) during the handover process from LTE to 5G.

[0019] Therefore, one of the purposes to be achieved by the embodiments disclosed herein is to provide the following apparatus, method and program, wherein the apparatus, method and program facilitate appropriately configuring the AS layer of the target RAT in a handover between a bearer-based network (e.g., LTE) and a bearer-free network (e.g., 5G). It should be noted that the above purpose is only one of the purposes to be achieved by the embodiments disclosed herein. Other purposes or problems and novel features will become apparent through the following description and drawings.

[0020] Solutions for solving problems

[0021] In one aspect, a target radio access network node, i.e., a target RAN node, is associated with a bearerless network, the target RAN node comprising: at least one memory; and at least one processor connected to the at least one memory. The at least one processor is configured to receive a handover request message from a core network for requesting a handover of a wireless terminal from a bearer-based network to the bearerless network. The handover request message comprises flow information related to at least one session to be established in the bearerless network for transmitting at least one packet flow of the wireless terminal. The at least one processor is further configured to send a handover request confirmation message containing a target-to-source transparent container to the core network in response to the handover request message. The target-to-source transparent container comprises radio resource configuration information derived from the flow information, and the target-to-source transparent container is to be forwarded to a source RAN node associated with the bearer-based network via the core network.

[0022] In one aspect, a source radio access network node, namely a source RAN node, is associated with a bearer-based network, the source RAN node comprising: at least one memory; and at least one processor connected to the at least one memory. The at least one processor is configured to send a handover request message for starting a handover of a wireless terminal from the bearer-based network to a bearer-free network to a core network, and receive a handover command message containing a target-to-source transparent container from the core network. The target-to-source transparent container is generated by a target RAN node associated with the bearer-free network, and includes radio resource configuration information required by the wireless terminal to establish a radio connection, the radio connection being associated with at least one session to be established in the bearer-free network in order to transmit at least one packet flow of the wireless terminal. The at least one processor is also configured to send a mobility command message containing the radio resource configuration information and indicating a handover to the bearer-free network to the wireless terminal.

[0023] In one aspect, a wireless terminal comprises: at least one memory; and at least one processor connected to the at least one memory. The at least one processor is configured to receive a mobility command message indicating a switch from a bearer-based network to an unbearable network from a radio access network node (RAN node) associated with a bearer-based network. The mobility command message is generated by a target RAN node associated with the unbearable network and includes radio resource configuration information required by the wireless terminal to establish a radio connection, the radio connection being associated with at least one session to be established in the unbearable network in order to transmit at least one packet flow of the wireless terminal. The at least one processor is also configured to establish the radio connection with the target RAN node associated with the unbearable network by using the radio resource configuration information.

[0024] On the one hand, a method in a target radio access network node, i.e., a target RAN node, the target RAN node being associated with a bearerless network, the method comprising: receiving from a core network a handover request message for requesting a handover of a wireless terminal from a bearer-based network to the bearerless network, the handover request message comprising flow information related to at least one session to be established in the bearerless network for transmitting at least one packet flow of the wireless terminal; and in response to the handover request message, sending a handover request confirmation message containing a target-to-source transparent container to the core network, the target-to-source transparent container comprising wireless resource configuration information derived from the flow information, the target-to-source transparent container to be forwarded via the core network to a source RAN node associated with the bearer-based network.

[0025] On the one hand, a method in a source radio access network node, i.e., a source RAN node, wherein the source RAN node is associated with a bearer-based network, the method comprising: sending a switching requirement message for starting a switching of a wireless terminal from the bearer-based network to an unbearable network to a core network; receiving a switching command message including a target-to-source transparent container from the core network, wherein the target-to-source transparent container is generated by a target RAN node associated with the unbearable network and includes wireless resource configuration information required by the wireless terminal to establish a wireless connection, wherein the wireless connection is associated with at least one session to be established in the unbearable network in order to transmit at least one packet flow of the wireless terminal; and sending a mobility command message including the wireless resource configuration information and indicating a switching to the unbearable network to the wireless terminal.

[0026] On the one hand, a method in a wireless terminal comprises: receiving a mobility command message indicating a switch from a bearer-based network to an unbearable network from a radio access network node, i.e., a RAN node, associated with a bearer-based network, the mobility command message being generated by a target RAN node associated with the unbearable network and comprising wireless resource configuration information required by the wireless terminal to establish a wireless connection, the wireless connection being associated with at least one session to be established in the unbearable network in order to transmit at least one packet flow of the wireless terminal; and establishing the wireless connection with the target RAN node associated with the unbearable network by using the wireless resource configuration information.

[0027] In one aspect, a program comprises a set of instructions (software codes), wherein the set of instructions (software codes) when loaded into a computer causes the computer to perform the method according to the above aspect.

[0028] Effects of the Invention

[0029] According to the above aspects, the following device, method and program can be provided, wherein the device, method and program help to appropriately configure the AS layer of the target RAT in switching between a bearer-based network (e.g., LTE) and a bearer-free network (e.g., 5G). BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Shown is an example of the structure of a wireless communication network according to some embodiments.

[0031] Figure 2 Shown is an example of the structure of a wireless communication network according to some embodiments.

[0032] Figure 3A is a sequence diagram showing an example of an Inter-RAT handover procedure from an LTE system to an NG system according to the first embodiment.

[0033] Figure 3B is a sequence diagram showing an example of an Inter-RAT handover procedure from an LTE system to an NG system according to the first embodiment.

[0034] Figure 4A is a sequence diagram showing another example of the Inter-RAT handover procedure from the LTE system to the NG system according to the first embodiment.

[0035] Figure 4B is a sequence diagram showing another example of the Inter-RAT handover procedure from the LTE system to the NG system according to the first embodiment.

[0036] Figure 5 is a flow chart showing an example of a method performed by a core network according to the first embodiment.

[0037] Figure 6 is a flowchart showing an example of a method performed by a target NR Node B (NR NB) according to the first embodiment.

[0038] Figure 7 is a flow chart showing an example of a method performed by a source LTE eNB according to the first embodiment.

[0039] Figure 8 is a flowchart showing an example of a method performed by the wireless terminal according to the first embodiment.

[0040] Fig. 9A is a sequence diagram showing an example of an Inter-RAT handover procedure from an NG system to an LTE system according to the second embodiment.

[0041] Fig. 9Bis a sequence diagram showing an example of an Inter-RAT handover procedure from an NG system to an LTE system according to the second embodiment.

[0042] Fig. 10A is a sequence diagram showing another example of the Inter-RAT handover procedure from the NG system to the LTE system according to the second embodiment.

[0043] Fig. 10B is a sequence diagram showing another example of the Inter-RAT handover procedure from the NG system to the LTE system according to the second embodiment.

[0044] Fig.11 is a block diagram showing an example of the structure of a wireless terminal according to some embodiments.

[0045] Fig.12 is a block diagram showing a structural example of a base station according to some embodiments.

[0046] Fig.13 is a block diagram showing a structural example of a base station according to some embodiments.

[0047] Fig.14 is a block diagram illustrating a structural example of a core network node according to some embodiments.

[0048] Fig.15A An example of the format of a Mobility from EUTRA command message is shown.

[0049] Fig. 15B An example of the format of a Mobility Command message from EUTRA is shown.

[0050] Fig.16 An example of the format of a handover request message is shown.

[0051] Fig.17 An example of the format of a handover request message is shown.

[0052] Fig.18 An example of the format of a source NR NB to target NR NB transparent container is shown.

[0053] Fig.19 An example of the format of a source NR NB to target NR NB transparent container is shown.

[0054] Fig. 20 An example of the format of a source NR NB to target NR NB transparent container is shown.

[0055] Fig.21 An example of the format of a (NR) Handover Request message is shown.

[0056] Fig. 22 An example of the format of a (NR) Handover Request message is shown.

[0057] Fig.23 An example of the format of a (NR) Handover Request message is shown.

[0058] Fig.24 An example of the format of slice information is shown.

[0059] Fig.25 An example of the format of a session endpoint ID is shown.

[0060] Fig.26 An example of the format of a (NR) Handover Request Confirm message is shown.

[0061] Fig. 27 An example showing the format of a target-to-source transparent container.

[0062] Fig.28 An example of the format of a (NR) Handover Request Confirmation is shown.

[0063] Fig.29 An example of the format of a (NR) Handover Request Confirmation is shown.

[0064] Fig.30 An example of the format of a forwarding address is shown.

[0065] Fig.31 An example of the format of the S1AP Handover Command message is shown.

[0066] Fig.32 An example of the format of an NG2AP handover command message is shown. DETAILED DESCRIPTION

[0067] The specific embodiments are described in detail below with reference to the accompanying drawings. In the entire drawings, the same reference numerals are used to represent the same or corresponding elements, and for the sake of clarity, repeated descriptions will be omitted as needed.

[0068] Each embodiment described below can be used alone, or two or more of these embodiments can be appropriately combined with each other. These embodiments include novel features that are different from each other. Therefore, these embodiments help to achieve different purposes or solve different problems from each other, and also help to obtain different advantages from each other.

[0069] First embodiment

[0070] Figure 1 An example of a structure of a wireless communication network according to some embodiments including this embodiment is shown. Figure 1In the example shown, the wireless communication network includes a wireless terminal (UE) 1, an LTE base station (i.e., eNB) 2, a new radio (NR) base station (i.e., NR Node B (NR NB)) 3, an EPC 4, and a NextGen (NG) core 5. UE 1 has the ability to connect to an LTE system including LTE eNB 2 and EPC 4, and has the ability to connect to a NextGen (NG) system including NR NB 3 and NG core 5.

[0071] exist Figure 1 In the example shown, the EPC 4 is connected to the NG core 5. Specifically, one or more nodes in the EPC 4 are connected to one or more nodes in the NG core 5 via a control plane interface. In some implementations, the MME in the EPC 4 may be connected to a control node (i.e., a control plane function (CPF) node) included in the NG core 5 having at least a portion of the MME function via a control plane interface. In addition, one or more nodes in the EPC 4 may be connected to one or more data nodes (i.e., a user plane function (UPF) node) in the NG core 5 via a user plane interface. Each data node (i.e., UPF node) may be a node having at least a portion of the S-GW function. That is, the EPC 4 may be enhanced to interoperate with an NG system including the NG core 5, and may be referred to as an eEPC.

[0072] Likewise, the NR NB 3 may be connected to one or more CPF nodes in the NG core 5 via a control plane interface (e.g., NG2 interface). In addition, the NR NB 3 may be connected to one or more UPF nodes in the NG core 5 via a user plane interface (e.g., NG3 interface). In addition, the UE 1 may be connected to one or more CPF nodes in the NG core 5 via a control plane interface (e.g., NG1 interface). The NG1 interface may be defined as a logical interface for transmitting NAS layer information, and the transmission of the NAS layer information may be performed via the NG2 interface as well as via a wireless interface (e.g., NG Uu) between the NR NB 3 and the UE 1.

[0073] Figure 2 Another structural example of a wireless communication network according to some embodiments including this embodiment is shown. Figure 2In the example shown, the LTE eNB 2 is connected to the NG core 5. That is, the LTE eNB 2 is connected to the MME in the NG core 5 or a control node (i.e., a CPF node) having at least a portion of the MME function via a control plane interface (e.g., an NG2 interface). In addition, the LTE eNB 2 is connected to the serving gateway (S-GW) in the NG core 5 or a data node (i.e., a UPF node) having at least a portion of the S-GW function via a user plane interface (e.g., an NG3 interface). As described above, the LTE eNB 2 may be enhanced to be connected to the NG core 5 and may be referred to as an eLTE eNB. In some implementations, the NG core 5 may be provided with a virtualized network slice that provides a logical EPC node and an EPC function. In some implementations, the E-UTRAN including the LTE eNB 2 may be connected to the same network slice as the NG RAN including the NRNB 3. Alternatively, the E-UTRAN including the LTE eNB 2 and the NG RAN including the NR NB 3 may be connected to different network slices from each other.

[0074] exist Figure 1 and Figure 2 In the example shown, LTE eNB 2 can be connected to NR NB 3 via a direct inter-base station interface (e.g., X3 interface). The direct inter-base station interface can be used for signaling, user packet transmission, or both between LTE eNB 2 and NR NB 3. However, the direct inter-base station interface between LTE eNB 2 and NR NB 3 can be omitted.

[0075] In addition to the above-mentioned NG1 interface, NG2 interface and NG3 interface, the NG system may also include other interfaces. Each interface may be referred to as a reference point. NG RAN (i.e., different NR NBs) may be connected to each other via the NX2 interface. A CPF node having either or both of a mobility management function (MMF) and a session management function (SMF) may be connected to a UPF node via a control plane interface (e.g., NG4 interface). Different UPF nodes may be connected to each other via a user plane interface (e.g., NG9 interface). CPF nodes with different functions may be connected to each other via a control plane interface. For example, a CPF node having MMF and SMF may be connected to a CPF node having a policy control function (PCF) via a control plane interface (e.g., NG7 interface). A CPF node having MMF and SMF may be connected to a node having a user data management (SDM) function via a control plane interface (e.g., NG8 interface). A CPF node may be connected to a node having an application function (AF) via a control plane interface (e.g., NG5 interface). The UPF node can be connected to an external or local data network (DN) via a user plane interface (e.g., NG6 interface). The SMF may include functions for authenticating users or terminals and authorizing services or network slices. The above network nodes are individually or collectively referred to as network functions (NFs).

[0076] The NG system including NR NB 3 and NG core 5 supports data transmission based on the above-mentioned flow-based QoS (or QoS for each flow) concept. The NG system including NR NB 3 and NG core 5 can also be configured to support bearer-based transmission using bearers for each QoS level and for each PDU session. The bearers in the NG system can be configured between a pair of network functions (NFs) (for example, between NR NB 3 and a user plane function in the NG core 5, or between two user plane functions in the NG core 5). Optionally, the bearers in the NG system can be configured between UE 1 and the user plane function in the NG core 5 via NR NB 3. The bearers in the NG system may be referred to as NG-EPS bearers, and the radio access bearers in the NG system may be referred to as NG-RABs. The bearers in the NG system can be used to transmit multiple packet flows (i.e., PDU flows).

[0077] The NG-RAB may include a radio bearer configured between the UE 1 (NG UE) and the NR NB 3, and a bearer (e.g., an NG3 bearer) configured between the NR NB 3 and the user plane function in the NG core 5 (e.g., an edge gateway (edge ​​GW)). The NG-EPS bearer may include the NG-RAB, and a core network bearer (e.g., an NG9 bearer) configured between the user plane functions in the NG core 5 (e.g., between the edge GW and the data network gateway (DN GW)). The edge GW is a gateway to the radio access network and has similar user plane functions to the LTE S-GW. However, in the NG system, unlike the LTE S-GW, the UE 1 can be connected to multiple edge GWs. The DN GW is a gateway to the external network (i.e., the data network) and has similar user plane functions to the LTE P-GW. In the NG system, like the LTE P-GW, the UE 1 can be connected to multiple DN GWs.

[0078] More specifically, an NG-EPS bearer may be configured between UE 1 (i.e., NG UE) and a slice-specific user plane function (i.e., slice-specific user plane NF (SUNF)) in the NG core 5. An NG-RAB may be configured between UE 1 (i.e., NG UE) and a common user plane function (i.e., common user plane NF (CUNF)) in the NG core 5. In this case, CUNF provides the function of an edge GW, and SUNF provides the function of a DN GW. CUNF may associate the NG-RAB with a core network bearer (e.g., NG9 bearer). That is, the NG-EPS bearer may include the NG-RAB between UE 1 (i.e., NG UE) and CUNF and a core network bearer (e.g., NG9 bearer) between CUNF and SUNF.

[0079] The NG system supporting bearer-based transmission may also be configured to identify data flows (e.g., PDU flows) in the bearer to perform QoS processing (e.g., packet discard) on a per-data-flow basis (e.g., per-PDU-flow basis). For example, NR NB3 may associate a bearer (e.g., NG3 bearer) configured between NR NB 3 and a user plane function in the NG core 5 with a radio bearer, perform packet forwarding between the bearer (e.g., NG3 bearer) and the radio bearer, and perform QoS processing (e.g., packet discard) on each data flow (e.g., PDU flow) in the bearer.

[0080] Note that in the case where the (e)LTE eNB 2 is connected to the NG core 5 via the NG2 interface, the radio access bearer corresponding to the EPS radio access bearer (E-RAB) of LTE can be defined as an NG EPS radio access bearer (NE-RAB), and the bearer corresponding to the EPS bearer of LTE can be defined as an NG EPS bearer (NEPS bearer). The NE-RAB may include a radio bearer configured between the UE 1 and the LTE eNB 2, and a bearer configured between the LTE eNB 2 and a user plane function in the NG core 5 (e.g., an edge GW or a CUNF) (e.g., an NG3 bearer). The NEPS bearer may include the NE-RAB, and a core network bearer configured between user plane functions in the NG core 5 (e.g., between the edge GW and the DN GW, or between the CUNF and the SUNF) (e.g., an NG9 bearer).

[0081] The LTE eNB 2 connected to the NG system may be configured to identify data flows (e.g., PDU flows) in the NE-RAB to perform QoS processing (e.g., packet discarding) on ​​a per-data-flow basis (e.g., on a per-PDU-flow basis). For example, the LTE eNB 2 may associate a bearer (e.g., NG3 bearer) configured between the LTE eNB 2 and the user plane function in the NG core 5 with a radio bearer, perform packet forwarding between the bearer (e.g., NG3 bearer) and the radio bearer, and perform QoS processing (e.g., packet discarding) on ​​each data flow (e.g., PDU flow) in the bearer.

[0082] This embodiment provides a method for handing over UE 1 from an LTE system (ie, a bearer-based network) to an NG system (ie, a bearer-free network). Figure 3A and 3B The method for transferring UE 1 from Figure 1 An example of a process of switching from an LTE system to an NG system in the structure example of a wireless communication network shown. Figure 3A shows the switching preparation stage, while Figure 3B The handover execution phase is shown.

[0083] exist Figure 3A and 3B In the process shown, the source base station (ie, LTE eNB 2) initiates handover by sending a handover required message on the interface (or reference point) between the source base station (ie, LTE eNB 2) and the core network (ie, EPC 4). Figure 3A and 3B The process shown may be an enhancement / evolution of the "E-UTRAN to UTRAN Iu mode inter-RAT handover" in LTE. Optionally, Figure 3A and 3BThe procedure shown may be an enhancement / evolution of "S1 based handover" with MME relocation in LTE.

[0084] In step 301, UE 1 is connected to LTE eNB 2 and is in a connected state (i.e., RRC_Connected). UE 1 receives measurement configuration from LTE eNB 2, performs neighbor cell measurement including measurement of E-UTRAN (LTE) cells and NG-RAN cells and inter-radio access technology (inter-RAT) measurement according to the received measurement configuration, and sends a measurement report to LTE eNB 2. The measurement configuration is included in an RRC connection reconfiguration message sent from E-UTRAN to UE, for example.

[0085] In step 302, LTE eNB 2 determines to perform an inter-RAT handover to the cell of NR NB 3, and sends a handover requirement message to the source control node (i.e., source MME) in EPC 4. The handover requirement message includes an identifier of the target NR NB 3. In addition, the handover requirement message may include a handover type information element (IE) indicating that the handover is a handover from LTE to NR. For example, "LTEtoNR" is set in the handover type IE. Additionally or optionally, the handover requirement message may include a target NR-NB identifier information element (IE). The handover requirement message may include a source to target transparent container IE. The source to target transparent container IE may include RRC layer information (e.g., RRC container) and may also include information related to bearers (e.g., E-RAB). The RRC layer information (e.g., RRC container) includes, for example, at least a portion of the radio resource configuration in the service cell of UE 1 managed by LTE eNB2, which is required for the radio resource configuration in NR NB3.

[0086] In step 303, the source MME in EPC 4 determines that the type of handover is an inter-RAT handover to NR (or NG system) based on the handover type IE or target NR-NB identifier IE contained in the received handover request message. The MME in EPC 4 selects a target control node in the NG core 5. The target control node is a node having at least part of the functions of the MME in EPC 4. The MME in EPC 4 sends a forward relocation request message to the target control node to start the handover resource allocation process. The forward relocation request message contains a mobility management (MM) context and all PDN connections valid for UE1 in the source system (i.e., LTE system). Each PDN connection includes a list of associated APNs and EPS bearer contexts. The MM context includes information related to the EPS bearer context and security-related information. The forward relocation request message also includes information for identifying one or more service data flows associated with each EPS bearer context (e.g., an SDF template or a traffic flow template (TFT)).

[0087] In step 304, the target control node in the NG core 5 performs a process for creating a bearerless session. Specifically, the target control node determines that it is necessary to relocate the packet transmission node (or gateway) used by UE 1, and then selects the target transmission node (or gateway) in the NG core 5. The target transmission node (or gateway) is a node having at least part of the functionality of the S-GW in the EPC 4. The target control node sends a create session request message to the target transmission node (or gateway). The create session request message includes information (e.g., an SDF template or a traffic flow template (TFT)) for identifying one or more service data flows associated with each EPS bearer context. The information for identifying one or more service data flows is derived from a forwarding relocation request message that has been sent from the source MME in the EPC 4 to the target control node in the NG core 5. The target transmission node (or gateway) allocates its local resources and sends a create session response message to the target control node.

[0088] In addition, in step 304, the target control node (e.g., CPF) in the NG core 5 may determine (or select) the network slice to which the UE 1 is to be connected after the handover. In one example, the target control node (e.g., CPF) in the NG core 5 may select the network slice used by the UE 1 based on the QoS required by the EPS bearer or SDF of the UE 1. Additionally or optionally, the forwarding relocation request message (step 303) sent by the source MME in the EPC 4 may also include network slice assistance information. The network slice assistance information assists the target control node in selecting, configuring or authorizing a network slice. The source MME in the EPC 4 may receive at least a portion of the network slice assistance information from the UE 1 and send it to the target control node in the NG core 5. The target control node in the NG core 5 may create the selected network slice instance.

[0089] The network slice auxiliary information may, for example, indicate any one of the following or any combination thereof: the type of UE 1 (e.g., device type or UE category); the access purpose of UE 1 (e.g., UE usage type); the service type desired by UE 1 (e.g., requested / preferred service type, multi-dimensional descriptor (MDD)); the slice information selected by UE 1 (e.g., selected slice type, selected slice identification (ID), or selected network function (NF) ID); the slice information previously authorized by UE 1 (e.g., authorized slice type, authorized slice ID, or authorized NF ID); the acceptable delay of UE 1 (e.g., allowed delay or tolerable delay). The service type may, for example, indicate the type of use case, such as broadband communication (e.g., enhanced mobile broadband: eMBB), high reliability / low latency communication (e.g., ultra-reliable and low latency communication: URLLC), M2M communication with a large number of connections (e.g., massive machine type communication: mMTC), or similar types thereof. The slice ID may, for example, indicate any one of the following or any combination thereof: slice instance information (e.g., network slice instance (NSI) ID); dedicated network information (e.g., dedicated core network (DCN) ID); and network domain name information (e.g., domain network name (DNN) ID). The NF ID may, for example, indicate an identifier of any one of the following or any combination thereof: a public network function (e.g., a public NF (CNF)); a public control plane function (e.g., a public control plane NF (CCNF)); a public user plane function (e.g., a public user plane NF (CUNF)); and a data gateway (e.g., a data network gateway (DN GW)).

[0090] In step 305, the target control node in the NG core 5 sends an NR handover request message to the target NR NB 3. The NR handover request message includes flow information. The flow information relates to at least one session (i.e., PDU session) established in a bearerless network (i.e., NG system) to transmit at least one packet flow (i.e., PDU flow) of UE 1. With respect to each packet flow (i.e., PDU flow) of UE 1, the flow information includes: a flow identifier (e.g., PDU flow ID); an address (e.g., transport layer address) and an uplink (UL) session endpoint identifier (SEID) of a transmitting node in the NG core 5; and flow QoS parameters. The session endpoint identifier (SEID) can be, for example, a tunnel endpoint identifier (TEID) or a network function (or node) identifier (NF ID). The TEID can be, for example, a GTP-TEID or a GRE-TEID.

[0091] The flow information may also indicate the mapping between the EPS bearers and PDU flows used by UE 1. For example, the flow information may indicate one or more SDFs mapped to each EPS bearer of UE 1 and a flow identifier (e.g., PDU flow ID) assigned to each of the one or more SDFs. The flow information may also include priority information (e.g., a priority indicator), flow type information (e.g., a flow type indicator), or a flow level. The priority information may, for example, indicate a relative priority order between multiple flows or an absolute priority order of each flow. The flow type information may, for example, indicate which use case or which service the flow corresponds to. In addition, the flow level may, for example, indicate one of the predefined flow types (e.g., lossless, delay tolerant, delay sensitive, and mission critical).

[0092] In addition, the NR handover request message in step 305 may include slice information. The slice information includes information related to at least one of: a network slice included in the NG core 5 to which the UE 1 will be connected (or to which the UE 1 is to be connected) after the handover; a network slice included in the NG core 5 to which the UE 1 is allowed to be connected; and a network slice included in the NG core 5 to which the UE 1 can be connected.

[0093] Specifically, the slice information may include identification information of the determined (or selected) slice (i.e., network slice: NS), identification information of the network node (NF), or type information of the slice, or any combination thereof. The slice identification information may be, for example, a slice ID, an NSI ID, an MDD, a DCN ID, or a DNN, or any combination thereof. The identification information of the network node may include, for example, an NF ID, a CNF ID, a CCNF ID, a SCNF ID, a CUNF ID, a SUNF ID, an UPF ID, or a DN GW ID, or any combination thereof. The slice type information may include, for example, a slice type indicating any one or any combination of a service type, a service category, and a use case. Additionally or optionally, the slice type information may include a tenant ID indicating a use case or a subscription contract (subscription group, for example, a home UE or a roaming UE). The slice type information may include an MDD containing a slice type and a tenant ID as its elements. Note that the content of the above-mentioned slice information may be specified for each network slice. Therefore, in the case where UE 1 is to be connected to multiple network slices at the same time, the slice information may include multiple groups of information items corresponding to the number of network slices to which UE 1 is to be connected.

[0094] The slice information may also include a mobility class or a session class, or both. The mobility class may indicate one of the predefined mobility levels (e.g., high mobility, low mobility, and no mobility). For example, high mobility means that the geographical area in which the network slice supports the mobility of UE 1 (or permits movement to UE 1) is larger than that of low mobility, and the level required for the continuity of the service (or PDU session) during switching is higher. No mobility means that the network slice supports the mobility of UE 1 (or permits movement to UE 1) only in a very limited geographical area. The mobility class may be specified for each UE, or the mobility class may be specified for each network slice. The session class may indicate one of the predefined session types (e.g., session pre-setup, session post-setup, and PDU-free session). For example, in order to maintain the service (or PDU session) during mobility as in the case of existing handover, the session pre-setup may indicate that a PDU session needs to be established before the UE completes the movement to the target (i.e., cell, beam, etc.). In contrast, the session post-setup may indicate that the PDU session can be established after the UE has moved to the target. A session level may be specified for each PDU session. The mobility level and session level may be included in the slice type. In other words, the slice type may include multiple attributes including the mobility level and the session level. Note that the above-mentioned flow information may include the mobility level, the session level, or both.

[0095] The slice information may include at least a portion of the network slice assistance information. That is, in step 305, the target control node in the NG core 5 may include at least a portion of the network slice assistance information received from the source MME in the EPC 4 in the slice information contained in the NR handover request message, and forward it to the target NR NB 3.

[0096] In step 306, upon receiving the NR handover request message containing the flow information, the target NR NB 3 generates a UE context including information related to the packet flow (i.e., PDU flow) and the security context, and allocates resources. In addition, the target NRNB 3 generates (or derives from the slice information) the radio resource configuration information (e.g., radio parameters) required by the UE 1 to establish a radio connection (e.g., RRC connection or radio bearer) associated with the bearerless network (i.e., NG system) based on the flow information. The radio resource configuration information may include at least one parameter included in the flow information. The radio resource configuration information may include system information (e.g., system information block: SIB) related to the cell (or mobility area or beam coverage area) of the NR NB 3, a public radio resource configuration of the UE (e.g., public resource configuration), or a dedicated radio resource configuration of the UE (e.g., dedicated resource configuration). The radio resource configuration information may also include information indicating the mapping between the bearer (e.g., EPS bearer or data radio bearer (DRB)) in the cell of the source LTE eNB 2 and the flow (e.g., PDU flow) to be established in the cell of the target NR NB 3.

[0097] Then, the target NR NB 3 sends an NR handover request confirmation message containing a target-to-source transparent container to the target control node. The target-to-source transparent container contains the radio resource configuration information generated by the target NR NB 3. As described later, the target-to-source transparent container is forwarded to the source LTE eNB 2 via the core network (i.e., EPC 4 and NG core 5).

[0098] In addition, in step 306, the target NR NB 3 may perform admission control based on the NR handover request message containing slice information. For example, the target NR NB 3 may determine whether to accept the bearer or flow for each bearer or for each flow. Additionally or optionally, the target NR NB 3 may perform admission control for each network slice to which UE 1 is to be connected based on the slice information. In this process, NR NB 3 may determine whether NR NB 3 can accept each network slice. In the event that there is a network slice that NR NB 3 cannot accept (or does not accept), NR NB 3 may map the network slice to a specific network slice (e.g., a default network slice), or may connect the network slice to a specific NF (e.g., CUPF). Optionally, NR NB 3 may determine that NR NB 3 has failed to accept the network slice.

[0099] In step 306, when generating UE context and wireless resource configuration information (e.g., wireless parameters), the target NRNB 3 may consider the slice information contained in the NR handover request message.

[0100] The radio resource configuration information derived from the slice information may include radio (or RAN) parameters for each network slice (or each use case). Use cases include, for example, enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low latency communication (URLLC). The radio parameters for each network slice (or each use case) may be basic physical channel parameters or basic layer 2 / layer 3 (L2 / L3) configuration. Basic physical channel parameters may include, for example, frame / subframe structure, transmission time interval (TTI) length, subcarrier spacing, and physical random access channel (PRACH) resources. PRACH resources may be either or both of the preamble index and time / frequency resources. The basic L2 / L3 configuration may include, for example, a frame / subframe mode and a configuration of the L2 protocol sublayer (L2 configuration, for example, PDCP config, RLC config, or MAC config).

[0101] Additionally or optionally, in the RRC layer signaling that specifies (or indicates) wireless resource configuration information derived from slice information, at least one of the following is different for each slice: the message structure; the format of the information element (IE); the parameter value; and the objects to be encoded and decoded according to ASN.1 (Abstract Syntax Notation One) that defines the information structure.

[0102] In step 307, the target control node in the NG core 5 sends a forwarding relocation response message containing the target to source transparent container to the source MME in the EPC 4. The forwarding relocation response message may also include the address and TEID allocated for downlink data forwarding. In the case of using indirect downlink forwarding, these addresses and TEIDs may be the addresses and TEIDs to the S-GW in the EPC 4. In the case of using direct downlink forwarding, these addresses and TEIDs may be the addresses and TEIDs to the target NR NB 3.

[0103] In step 308, the source MME sends a handover command message including the target to source transparent container to the source LTE eNB 2. The handover command message may also include a list of bearers as objects of downlink data forwarding (e.g., a list of bearers as objects of data forwarding). The "list of bearers as objects of data forwarding" IE includes, for example, an address and TEID used for user traffic data forwarding, and an identifier of a flow (e.g., a PDU flow) as an object of data forwarding. The source LTE eNB 2 starts data forwarding for the bearer or flow (e.g., a PDU flow) specified by the "list of bearers as objects of data forwarding" IE.

[0104] In step 309, the source LTE eNB 2 sends a radio resource control (RRC) message including a handover command message to the UE 1. The handover command message includes a transparent container including the radio resource configuration information that the target NR NB 3 has set in the preparation stage. The RRC message may be, for example, a mobility command message from EUTRA or an RRC connection reconfiguration message.

[0105] In step 310, upon receiving the RRC message including the handover command message, UE 1 moves to the target RAN (i.e., NG RAN) and performs handover according to the radio resource configuration information provided by the handover command message. That is, UE 1 establishes a radio connection with the target NR NB 3 associated with the bearerless network (i.e., NG system). In step 311, after successfully synchronizing to the target cell, UE 1 sends a handover confirmation for the NR message to the target NR NB 3. The message in step 311 may be an NR RRC connection reconfiguration complete message.

[0106] In step 312, when UE 1 successfully accesses the target NR NB 3, the target NR NB 3 notifies the target control node in the NG core 5 of the situation by sending an NR switching notification message.

[0107] In step 313, the target control node in the NG core 5 recognizes that the UE 1 has arrived at the target side and notifies the source MME in the EPC 4 of this by sending a forward relocation complete notification message. The source MME sends a forward relocation complete confirmation message to the target control node.

[0108] In step 314, the target control node in the NG core 5 performs a flow modification process, thereby completing the inter-RAT handover process. For example, the target control node may send a modify flow request message for each session (i.e., for each PDU session) to the transmission node in the NG core 5. The modify flow request message may include a flow identifier (e.g., PDU flow ID), and also include the address of the target NR NB 3 and a downlink (DL) session endpoint identifier (SEID). The session endpoint identifier (SEID) may be, for example, a tunnel endpoint identifier (TEID). The transmission node in the NG core 5 may communicate with the edge node (i.e., eP-GW) in the EPC 4 to notify the edge node (i.e., (e)P-GW) in the EPC 4 of the relocation of the transmission node or the change of the RAT type due to the inter-RAT HO. Specifically, the transmission node in the NG core 5 may send a modify bearer request message for each session (i.e., for each PDN connection) to the edge node in the EPC 4. The edge node in the NG core 5 may send a modify bearer response message to the transmission node in the NG core 5. The transmitting node in the NG core 5 may send a modify flow response message to the target control node.

[0109] In accordance with Figure 3A and 3B After the process handover shown is completed, the path described below can be used for data transmission for UE 1. In the case where the NG system including the NR NB 3 and the NG core 5 supports bearer-based transmission in the NG core 5 and uses a bearer (e.g., an NG-EPS bearer) for the UE 1 after the handover, both the uplink path and the downlink path can, for example, include a path (e.g., a GTP tunnel or a GRE tunnel) between the source (or old) S / P-GW and the target (or new) user plane function (e.g., CUNF) in the NG core 5. Specifically, the S / P-GW can transmit downlink data to the user plane function (e.g., CUNF) in the NG core 5, and the user plane function (e.g., CUNF) in the NG core 5 can transmit uplink data to the S / P-GW.

[0110] In contrast, in the case where no bearer (e.g., NG-EPS bearer) is used for UE 1 after switching, for example, CUNF can relay between the source (or old) S / P-GW and the target (or new) user plane function (e.g., SUNF with NW slicing function). Specifically, the S / P-GW can transmit downlink data to the CUNF in the NG core 5, and then the CUNF can transmit the downlink data to another UNF with flow control function. Optionally, data can be transmitted directly between the S / P-GW and the SUNF without going through the CUNF. The above-mentioned data transmission path after switching can also be used in other switching processes described below.

[0111] Figure 4A and 4B Shown for Figure 2 Another example of the process of switching UE 1 from the LTE system to the NG system in the structural example of the wireless communication network shown. Figure 4A shows the switching preparation phase, and Figure 4B The handover execution phase is shown.

[0112] and Figure 3A and 3B The same process is shown in Figure 4A and 4B In the process shown, the source base station (ie, LTE eNB 2) initiates the handover by sending a handover request message on the interface between the source base station (ie, LTE eNB 2) and the core network (ie, NG core 5). Figure 3A and 3B The process is the same as shown, Figure 4A and 4B The procedure shown may be an enhancement / evolution of "E-UTRAN to UTRAN Iu mode Inter-RAT handover" in LTE, or may be an enhancement / evolution of "S1 based handover" with MME relocation in LTE.

[0113] Figure 4A The processing of steps 401 and 402 in Figure 3A The processing of steps 301 and 302 in FIG. 4 is the same. However, in step 402, the LTE eNB 2 sends a handover request message to the NG core 5. As already explained, in Figure 2In the network structure example shown, the E-UTRAN including the LTE eNB 2 and the NG RAN including the NR NB 3 can be connected to the same network slice. In this implementation, the handover of the UE 1 from the LTE eNB 2 to the NR NB 3 is performed by signaling between one or more logical control nodes (i.e., control plane functions) and one or more logical transport nodes (i.e., user plane functions) created within the same network slice. In this implementation, the handover requirement message in step 402 can be sent to a new or enhanced control node corresponding to the MME.

[0114] Optionally, the E-UTRAN including the LTE eNB 2 and the NG RAN including the NR NB 3 may be connected to different network slices. In this implementation, the handover of the UE 1 from the LTE eNB 2 to the NR NB 3 is performed by inter-slice communication between the network slice instance corresponding to the EPC to which the LTE eNB 2 is connected and the network slice instance corresponding to the pure NG core to which the NR NB 3 is connected. In this implementation, the handover request message in step 402 may be sent to the MME in the network slice instance to which the LTE eNB 2 is connected.

[0115] Figure 4A The processing of steps 403 to 405 in Figure 3A The processing of steps 303 to 307 in is the same. Figure 4A In the process shown, the Figure 3A The processing corresponding to the processing in steps 303 and 307 is performed in the NG core 5.

[0116] Figure 4B The processing of steps 406 to 411 in Figure 3B The processing of steps 308 to 314 in is the same. Figure 4B In the process shown, the Figure 3B The processing corresponding to the processing in step 313 is performed in the NG core 5.

[0117] Figure 5 is a flow chart illustrating a process 500 as an example of a method performed by a core network. The core network corresponds to Figure 1 EPC 4 and NG core 5 as shown, or Figure 2 NG core 5 shown. In step 501, the core network receives a handover request message from the source LTE eNB 2 for starting the handover of UE 1 from the bearer-based network (LTE) to the bearer-free network (5G). Step 501 corresponds to Figure 3A Step 302 or Figure 4A Step 402 in .

[0118] In step 502, the core network sends a (NR) handover request message containing flow information related to at least one session to be established for UE 1 in the bearerless network to the target NR NB 3. Step 502 corresponds to Figure 3A Step 305 or Figure 4A Step 404 in .

[0119] In step 503, the core network receives a (NR) handover request confirmation message containing a target-to-source transparent container from the target NR NB 3. The target-to-source transparent container contains the radio resource configuration information required by the UE 1 to establish a radio connection associated with the bearerless network. Step 503 corresponds to Figure 3A Step 306 or Figure 4A Step 405 in .

[0120] In step 504, the core network sends a handover command message including the target to source transparent container to the source LTE eNB2. Step 504 corresponds to Figure 3B Step 308 or Figure 4B Step 406 in .

[0121] Figure 6 is a flow chart showing a process 600 as an example of a method performed by the target NR NB 3. In step 601, the target NR NB 3 receives a (NR) handover request message containing flow information related to at least one session established for the UE 1 in the bearerless network from the core network (i.e., the NG core 5). Step 601 corresponds to Figure 3A Step 305 or Figure 4A Step 404 in .

[0122] In step 602, the target NR NB 3 sends a (NR) handover request confirmation message containing a target-to-source transparent container to the core network. The target-to-source transparent container contains the radio resource configuration information required by UE 1 to establish a radio connection associated with the bearerless network. Step 602 corresponds to Figure 3A Step 306 or Figure 4A Step 405 in .

[0123] In step 603, the target NR NB 3 establishes a wireless connection associated with the bearerless network for UE 1 based on the wireless resource configuration information. Step 603 corresponds to Figure 3B Step 310 or Figure 4B Step 408 in .

[0124] Figure 77 is a flow chart showing a process 700 as an example of a method performed by the source LTE eNB 2. In step 701, the source LTE eNB 2 sends a handover request message to the core network (i.e., the EPC 4 or the NG core 5) for starting a handover of the UE 1 from a bearer-based network (LTE) to a bearer-free network (5G). Step 701 corresponds to Figure 3A Step 302 or Figure 4A Step 402 in .

[0125] In step 702, the source LTE eNB 2 receives a handover command message containing a target-to-source transparent container from the core network. The target-to-source transparent container contains the radio resource configuration information required by the UE 1 to establish a radio connection associated with the bearerless network. Step 702 corresponds to Figure 3B Step 308 or Figure 4B Step 406 in .

[0126] In step 703, the source LTE eNB 2 sends a mobility command message (eg, a handover command message) including radio resource configuration information and an instruction to handover to the bearerless network to the UE 1. Step 703 corresponds to Figure 3B Step 309 or Figure 4B Step 407 in .

[0127] Figure 8 8 is a flow chart showing a process 800 as an example of a method performed by UE 1. In step 801, UE 1 receives a mobility command message (e.g., a handover command message) from a source LTE eNB 2. The mobility command message contains radio resource configuration information required by UE 1 to establish a radio connection associated with an unsupported network. Step 801 corresponds to Figure 3B Step 309 or Figure 4B Step 407 in .

[0128] In step 802, UE 1 establishes a radio connection with a target NR NB 3 associated with an unhosted network by using the radio resource configuration information. Step 802 corresponds to Figure 3B Step 310 or Figure 4B Step 408 in .

[0129] The detailed process of switching from a bearer-based network (LTE) to an unbearer network (5G) according to this embodiment is not limited to the above specific examples. For example, the names of the messages in the switching process are not limited to the names of the messages shown in the above examples. In the above examples of the switching process, the order of the messages can be changed, and some of the messages can be omitted. In addition, the messages may include one or more additional messages.

[0130] As can be understood from the above description, the process of switching from a bearer-based network (LTE) to an unbearer network (5G) described in this embodiment includes:

[0131] - Send the flow information to the target NR NB 3 using the core network (NG Core 5);

[0132] - generating, using the target NR NB 3, radio resource configuration information required by the UE 1 to establish a radio connection (e.g., an RRC connection or a radio bearer) associated with the bearerless network (i.e., the NG system) based on the flow information; and

[0133] -Use the target NR NB 3 to send the radio resource configuration information to UE 1 via the source LTE eNB 2.

[0134] In this way, UE 1 uses the radio resource configuration information generated by the target NR NB 3 based on the flow information, thereby appropriately configuring the access stratum (AS) layer of the target RAT associated with the bearerless network (e.g., 5G).

[0135] As already explained, the NG system including the NR NB 3 and the NG core 5 may be configured to support bearer-based transmission using bearers for each QoS level and for each PDU session, or may be configured to identify data flows (e.g., PDU flows) in a bearer to perform QoS processing (e.g., packet discard) for each data flow (e.g., for each PDU flow). For example, the NRNB 3 may associate a bearer (e.g., NG3 bearer) configured between the NR NB 3 and the user plane function in the NG core 5 with a radio bearer, perform packet forwarding between the bearer (e.g., NG3 bearer) and the radio bearer, and perform QoS processing (e.g., packet discard) for each data flow (e.g., PDU flow) in the bearer.

[0136] In this case, the flow information described in this embodiment may indicate an association between a bearer (e.g., NG-RAB or NG3 bearer) used by UE 1 and one or more packet flows (i.e., PDU flows) of UE 1 transmitted via the bearer. In other words, the control node (e.g., CPF) in the NG core 5 may send flow information to NR NB 3 to notify NR NB 3 of an association between a bearer (e.g., NG-RAB or NG3 bearer) used by UE 1 and one or more packet flows (i.e., PDU flows) of UE 1 transmitted via the bearer. NR NB 3 may receive the flow information from the control node in the NG core 5, and then perform QoS processing (e.g., packet discard) for each data flow (e.g., PDU flow) in a bearer (e.g., NG3 bearer) configured between NR NB 3 and a user plane function in the NG core 5 based on the received flow information.

[0137] Second embodiment

[0138] This embodiment provides a method for handing over UE 1 from an NG system (ie, a bearer-free network) to an LTE system (ie, a bearer-based network). Fig. 9A and 9B Shown for Figure 1 An example of a process of switching UE 1 from an NG system to an LTE system is shown in the structural example of a wireless communication network. Fig. 9A shows the switching preparation stage, while Fig. 9B The handover execution phase is shown.

[0139] exist Fig. 9A and 9B In the process shown, the source base station (i.e., NR NB 3) initiates the handover by sending a handover request message on the interface (or reference point) between the source base station (i.e., NR NB 3) and the core network (i.e., NG Core 5). Fig. 9A and 9B The process shown may be an enhancement / evolution of "UTRAN Iu mode to E-UTRAN inter-RAT handover" in LTE. Optionally, Fig. 9A and 9B The procedure shown may be an enhancement / evolution of "S1 based handover" with MME relocation in LTE.

[0140] In step 901, UE 1 is connected to NR NB 3 and is in a connected state (e.g., RRC_Connected). UE 1 receives a measurement configuration from NR NB 3, performs neighbor cell measurement and inter-RAT measurement including measurement of NG-RAN cells and E-UTRAN (LTE) cells according to the received measurement configuration, and sends a measurement report to NR NB 3.

[0141] In step 902, NR NB 3 determines to perform an inter-RAT handover to the cell of LTE eNB 2, and sends a handover requirement message to the source control node in the NG core 5. The handover requirement message includes an identifier of the target LTE eNB 2. In addition, the handover requirement message may include a handover type information element (IE) indicating that the handover is a handover from NR to LTE. For example, "NRtoLTE" is set in the handover type IE. Optionally, the handover requirement message may include a target LTE eNB identifier information element (IE). The handover requirement message may include a source to target transparent container IE.

[0142] In step 904, the source control node in the NG core 5 determines that the type of handover is an inter-RAT handover to the LTE system based on the handover type IE or the target LTE eNB identifier IE contained in the received handover request message. The source control node in the NG core 5 selects the target MME in the EPC 4. The source control node in the NG core 5 sends a forwarding relocation request message to the target MME to start the handover resource allocation process. The forwarding relocation request message contains a mobility management (MM) context and all PDN connections valid for UE 1 in the source system (i.e., the NG system). Each PDN connection includes a list of associated APNs and PDU flow contexts. The MM context includes information related to the PDU flow and security-related information. The forwarding relocation request message also includes information for identifying one or more service data flows associated with each PDU flow context (e.g., an SDF template or a traffic flow template (TFT)).

[0143] In step 904, the target MME in the EPC 4 performs a process for creating a bearer-based session. Specifically, the target MME determines that the packet transfer node (or gateway) of the UE 1 needs to be relocated, and selects the target transfer node (i.e., S-GW) in the EPC 4. The target MME sends a create session request message to the target S-GW. The create session request message may include information (e.g., an SDF template or a traffic flow template (TFT)) for identifying one or more service data flows associated with each PDU flow context. The information for identifying one or more service data flows is derived from the forwarding relocation request message that has been sent from the source control node in the NG core 5 to the target MME in the EPC 4. The target S-GW allocates its local resources and sends a create session response message to the target MME.

[0144] In step 905 , the target MME in the EPC 4 sends a handover request message to the target LTE eNB 2 .

[0145] In step 906, upon receiving the handover request message, the target LTE eNB 2 generates a UE context including information related to the EPS bearer and a security context, and allocates resources. Then, the target LTE eNB 2 sends a handover request confirmation message including a target to source transparent container to the target MME.

[0146] In step 907, the target MME in the EPC 4 sends a forwarding relocation response message containing the target to source transparent container to the source control node in the NG core 5. The forwarding relocation response message may also include the address and TEID allocated for downlink data forwarding. In the case of using indirect downlink forwarding, these addresses and TEIDs may be the addresses and TEIDs of the transmitting node in the NG core 5. In the case of using direct downlink forwarding, these addresses and TEIDs may be the addresses and TEIDs of the target LTE eNB 2.

[0147] In step 908, the source control node sends a switching command message including a target-to-source transparent container to the source NRNB 3. The switching command message may also include a list of flows (e.g., PDU flows) that are objects of downlink data forwarding (e.g., a list of flows that are objects of data forwarding). The "list of flows that are objects of data forwarding" IE includes, for example, an address and TEID used for user traffic data forwarding, and an identifier of a flow that is an object of data forwarding (e.g., a PDU flow). The source NR NB 3 starts data forwarding for the flow (e.g., a PDU flow) specified by the "list of flows that are objects of data forwarding" IE.

[0148] In step 909, the source LTE eNB 2 sends an RRC message including a handover command message to UE 1. The handover command message includes a transparent container including the radio resource configuration information that the target LTE eNB 2 has set in the preparation stage. The RRC message may be, for example, a mobility command message or an RRC connection reconfiguration message from the NR.

[0149] In step 910, upon receiving the RRC message including the handover command message, UE 1 moves to the target RAN (i.e., E-UTRAN) and performs handover according to the radio resource configuration information provided by the handover command message. That is, UE 1 establishes a radio connection with the target LTE eNB 2 associated with the bearer-based network (i.e., LTE system). In step 911, after successfully synchronizing to the target cell, UE 1 sends a handover confirmation for the EUTRA message to the target LTE eNB 2. The message in step 911 may be an RRC connection reconfiguration complete message.

[0150] In step 912, when UE 1 successfully accesses target LTE eNB 2, target LTE eNB 2 notifies the target MME in EPC 4 of the situation by sending a handover notification message.

[0151] In step 913, the target MME in the EPC 4 recognizes that the UE 1 has arrived at the target side and notifies the source control node in the NG Core 5 of this by sending a forwarding relocation complete notification message. The source control node sends a forwarding relocation complete confirmation message to the target MME.

[0152] In step 914, the target (e)MME in EPC 4 performs a bearer modification process, thereby completing the inter-RAT handover process. For example, the target MME may send a modify bearer request message for each session (i.e., for each PDN connection) to the (e)S-GW in EPC 4. The modify bearer request message may include a bearer identifier (e.g., EPS bearer ID) and also include the address and downlink (DL) TEID of the target LTE eNB 2. The (e)S-GW in EPC 4 may communicate with the edge node in the NG core 5 to notify the edge node in the NG core 5 of the relocation of the transmission node or the change of the RAT type due to the inter-RAT HO. Specifically, the S-GW in EPC 4 may send a modify flow request message for each bearerless session (i.e., for each PDU session) to the edge node in the NG core 5. The edge node in the NG core 5 may send a modify flow response message to the S-GW in EPC 4. The S-GW in EPC 4 may send a modify bearer response message to the target MME.

[0153] Fig. 10A and 10B Shown for Figure 2 An example of a process of switching UE 1 from an NG system to an LTE system is shown in the structural example of a wireless communication network. Fig. 10A shows the switching preparation stage, while Fig. 10B The handover execution phase is shown.

[0154] and Fig. 9A and 9B The same process is shown in Fig. 10A and 10B In the process shown, the source base station (ie, NR NB 3) initiates the handover by sending a handover request message on the interface between the source base station (ie, NR NB 3) and the core network (ie, NG core 5). Fig. 9A and 9B The process is the same as shown, Fig. 10A and 10BThe procedure shown may be an enhancement / evolution of "UTRAN Iu mode to E-UTRAN Inter-RAT Handover" in LTE, or may be an enhancement / evolution of "S1 based handover" with MME relocation in LTE.

[0155] Fig. 10A The processing of steps 1001 to 1005 in Fig. 9A The processing of steps 901 to 907 in is the same. Fig. 10A In the process shown, the Fig. 9A The process corresponding to the process of step 903 and 907 is performed in the NG core 5.

[0156] Fig. 10B The processing of steps 1006 to 1011 in Fig. 9B The processing of steps 908 to 914 in is the same. Fig. 10B In the process shown, the Fig. 9B The process corresponding to the process of step 913 is performed in the NG core 5.

[0157] The detailed process of switching from an unloaded network (5G) to a load-based network (LTE) according to this embodiment is not limited to the above specific examples. For example, the names of the messages in the switching process are not limited to the names of the messages shown in the above examples. In the above examples of the switching process, the order of the messages can be changed, and some of the messages can be omitted. In addition, the messages may include one or more additional messages.

[0158] The following provides a structural example of UE 1, LTE eNB 2, NR NB 3 and core network nodes according to the above embodiment. Fig.11 1 is a block diagram showing a structural example of UE 1. LTE transceiver 1101 performs analog RF signal processing related to the PHY layer of LTE RAT to communicate with LTE eNB 2. The analog RF signal processing performed by LTE transceiver 1101 includes up-conversion, down-conversion and amplification. LTE transceiver 1101 is connected to antenna 1102 and baseband processor 1105. That is, LTE transceiver 1101 receives modulation symbol data (or OFDM symbol data) from baseband processor 1105, generates a transmit RF signal, and supplies the generated transmit RF signal to antenna 1102. In addition, LTE transceiver 1101 generates a baseband receive signal based on the receive RF signal received by antenna 1102, and supplies the generated baseband receive signal to baseband processor 1105.

[0159] The new radio (NR) transceiver 1103 performs analog RF signal processing related to the PHY layer of the NG RAT to communicate with the NR NB 3. The new 5G (NR) transceiver 1103 is connected to the antenna 1104 and the baseband processor 1105.

[0160] The baseband processor 1105 performs digital baseband signal processing (i.e., data plane processing) and control plane processing for wireless communication. Digital baseband signal processing includes (a) data compression / decompression, (b) data segmentation / concatenation, (c) generation / decomposition of transmission format (i.e., transmission frame), (d) channel coding / decoding, (e) modulation (i.e., symbol mapping) / demodulation, and (f) generation of OFDM symbol data (i.e., baseband OFDM signal) through inverse fast Fourier transform (IFFT). On the other hand, control plane processing includes communication management of layer 1 (e.g., transmit power control), layer 2 (e.g., radio resource management and hybrid automatic repeat request (HARQ) processing), and layer 3 (e.g., signaling related to attachment, mobility, and packet communication).

[0161] For example, in the case of LTE or LTE-Advanced, the digital baseband signal processing performed by the baseband processor 1105 may include signal processing of a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a medium access control (MAC) layer, and a physical (PHY) layer. In addition, the control plane processing performed by the baseband processor 1105 may include processing of a non-access stratum (NAS) protocol, an RRC protocol, and a MAC CE.

[0162] The baseband processor 1105 may include a modem processor (e.g., a digital signal processor (DSP)) for performing digital baseband signal processing and a protocol stack processor (e.g., a central processing unit (CPU) or a microprocessor unit (MPU)) for performing control plane processing. In this case, the protocol stack processor for performing control plane processing may be integrated with the application processor 1106 described below.

[0163] The application processor 1106 may also be referred to as a CPU, an MPU, a microprocessor, or a processor core. The application processor 1106 may include a plurality of processors (processor cores). The application processor 1106 loads a system software program (operating system (OS)) and various application programs (e.g., a communication application for acquiring metering data or sensing data) from the memory 1108 or from other memories (not shown), and executes these programs, thereby providing various functions of the UE 1.

[0164] In some implementations, such as Fig.11As shown by the dashed line (1107) in FIG. 1 , the baseband processor 1105 and the application processor 1106 may be integrated on a single chip. In other words, the baseband processor 1105 and the application processor 1106 may be implemented on a single system on chip (SoC) device 1107. The SoC device may be referred to as a system large scale integration (LSI) or a chipset.

[0165] The memory 1108 is a volatile memory, a non-volatile memory, or a combination thereof. The memory 1108 may include a plurality of memory devices that are physically independent of each other. The volatile memory is, for example, a static random access memory (SRAM), a dynamic RAM (DRAM), or a combination thereof. The non-volatile memory is, for example, a mask read-only memory (MROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a hard disk drive, or any combination thereof. The memory 1108 may include, for example, an external memory device that can be accessed by the baseband processor 1105, the application processor 1106, and the SoC 1107. The memory 1108 may include an internal memory device integrated in the baseband processor 1105, the application processor 1106, or the SoC 1107. In addition, the memory 1108 may include a memory in a universal integrated circuit card (UICC).

[0166] The memory 1108 may store one or more software modules (computer programs) 1109 including instructions and data for performing the processing described in the above embodiments using the UE 1. In some implementations, the baseband processor 1105 or the application processor 1106 may load the software module 1109 from the memory 1108 and execute the loaded software module, thereby performing the processing of the UE 1 described in the above embodiments.

[0167] Fig.12 2 is a block diagram showing a structural example of the LTE eNB 2 according to the above-mentioned embodiment. Fig.12 As shown, LTEeNB 2 includes an LTE transceiver 1201, a network interface 1203, a processor 1204, and a memory 1205. The LTE transceiver 1201 performs analog RF signal processing to communicate with UEs supporting LTE RAT including UE 1. The LTE transceiver 1201 may include a plurality of transceivers. The LTE transceiver 1201 is connected to an antenna 1202 and a processor 1204. The LTE transceiver 1201 receives modulation symbol data (or OFDM symbol data) from the processor 1204, generates a transmit RF signal, and supplies the generated transmit RF signal to the antenna 1202. In addition, the LTE transceiver 1201 generates a baseband receive signal based on the receive RF signal received by the antenna 1202, and supplies the signal to the processor 1204.

[0168] The network interface 1203 is used to communicate with network nodes, such as the MME and S-GW in the EPC 4. The network interface 1203 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0169] The processor 1204 performs digital baseband signal processing (i.e., data plane processing) and control plane processing for wireless communication. For example, in the case of LTE or Advanced LTE, the digital baseband signal processing performed by the processor 1204 may include signal processing of the PDCP layer, the RLC layer, the MAC layer, and the PHY layer. In addition, the control plane processing performed by the processor 1204 may include processing of the S1 protocol, the RRC protocol, and the MAC CE.

[0170] The processor 1204 may include a plurality of processors. The processor 1204 may include, for example, a modem processor (eg, DSP) for performing digital baseband signal processing and a protocol stack processor (eg, CPU or MPU) for performing control plane processing.

[0171] The memory 1205 includes a combination of a volatile memory and a non-volatile memory. The volatile memory is, for example, an SRAM, a DRAM, or a combination thereof. The non-volatile memory is, for example, an MROM, a PROM, a flash memory, a hard disk drive, or a combination thereof. The memory 1205 may include a memory configured separately from the processor 1204. In this case, the processor 1204 may access the memory 1205 via the network interface 1203 or an I / O interface (not shown).

[0172] The memory 1205 may store one or more software modules (computer programs) 1206 including instructions and data for performing the processing described in the above embodiments using the LTE eNB 2. In some implementations, the processor 1204 may load one or more software modules 1206 from the memory 1205 and execute the loaded software modules, thereby performing the processing of the LTE eNB 2 described in the above embodiments.

[0173] Fig.13 is a block diagram showing a structural example of NR NB 3 according to the above-mentioned embodiment. Fig.13As shown, NR NB 3 includes a new radio (NR) transceiver 1301, a network interface 1303, a processor 1304, and a memory 1305. The NR transceiver 1301 performs analog RF signal processing to communicate with UEs supporting NG RAT including UE 1. The NR transceiver 1301 may include a plurality of transceivers. The NR transceiver 1301 is connected to an antenna 1302 and a processor 1304. The NR transceiver 1301 receives modulation symbol data from the processor 1304, generates a transmit RF signal, and supplies the generated transmit RF signal to the antenna 1302. In addition, the NR transceiver 1301 generates a baseband receive signal based on the receive RF signal received by the antenna 1302, and supplies the signal to the processor 1304.

[0174] The network interface 1303 is used to communicate with network nodes, such as a control node and a transmission node in the NG core 5. The network interface 1303 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0175] The processor 1304 performs digital baseband signal processing (i.e., data plane processing) and control plane processing for wireless communication. The processor 1304 may include multiple processors. The processor 1304 may include, for example, a modem processor (e.g., DSP) for performing digital baseband signal processing and a protocol stack processor (e.g., CPU or MPU) for performing control plane processing.

[0176] The memory 1305 includes a combination of a volatile memory and a non-volatile memory. The volatile memory is, for example, an SRAM, a DRAM, or a combination thereof. The non-volatile memory is, for example, an MROM, a PROM, a flash memory, a hard disk drive, or a combination thereof. The memory 1305 may include a memory configured separately from the processor 1304. In this case, the processor 1304 may access the memory 1305 via the network interface 1303 or an I / O interface (not shown).

[0177] The memory 1305 may store one or more software modules (computer programs) 1306 including instructions and data for performing the processing using NR NB 3 described in the above embodiments. In some implementations, the processor 1304 may load one or more software modules 1306 from the memory 1305 and execute the loaded software modules, thereby performing the processing of NR NB 3 described in the above embodiments.

[0178] Fig.14 1 is a block diagram showing a structural example of a core network node 1400 according to the above embodiment. The core network node 1400 is, for example, an MME in the EPC 4 or a control node in the NG core 5. Fig.14As shown, the core network node 1400 includes a network interface 1401, a processor 1402 and a memory 1403. The network interface 1401 is used to communicate with a network node (e.g., a RAN node or other core network node). The network interface 1401 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

[0179] The processor 1402 may be, for example, a microprocessor, an MPU, or a CPU. The processor 1402 may include a plurality of processors.

[0180] The memory 1403 includes a combination of a volatile memory and a non-volatile memory. The volatile memory is, for example, an SRAM, a DRAM, or a combination thereof. The non-volatile memory is, for example, an MROM, a PROM, a flash memory, a hard disk drive, or a combination thereof. The memory 1403 may include a memory configured separately from the processor 1402. In this case, the processor 1402 may access the memory 1403 via the network interface 1401 or an I / O interface (not shown).

[0181] The memory 1403 may store one or more software modules (computer programs) 1404 including instructions and data for performing the processing of the core network node (e.g., the MME in the EPC 4 or the control node in the NG core 5) described in the above embodiments. In some implementations, the processor 1402 may load one or more software modules 1404 from the memory 1403 and execute the loaded software modules, thereby performing the processing of the core network node described in the above embodiments.

[0182] As mentioned above Figures 11 to 14As described above, the processors included in the UE 1, LTE eNB 2, NR NB 3 and core network nodes in the above embodiments execute one or more programs including an instruction set for causing the computer to perform the algorithm described above with reference to the accompanying drawings. Various types of non-transitory computer-readable media can be used to store these programs and thus supply these programs to the computer. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include: magnetic recording media (such as floppy disks, magnetic tapes, and hard disk drives); magneto-optical recording media (such as magneto-optical disks); compact disk read-only memory (CD-ROM); CD-R; CD-R / W; and semiconductor memory (such as mask ROM, programmable ROM (PROM), erasable PROM (EPROM), flash ROM, and random access memory (RAM)). These programs can be supplied to the computer by using various types of temporary computer-readable media. Examples of temporary computer-readable media include electrical signals, optical signals, and electromagnetic waves. Temporary computer-readable media can be used to supply the program to the computer via a wired communication line (e.g., wires and optical fibers) or a wireless communication line.

[0183] Third embodiment

[0184] This embodiment provides a specific example of the RRC message described in the above embodiments and the control message between the RAN and the core network (ie, S1 message and NG2 message).

[0185] Fig.15A and 15B An example of the format of a mobility command message from EUTRA is shown. In the case of a handover from an LTE system to a NG system, the MobilityFromEUTRACommand message includes a purpose set to "handover" and a targetRAT-Type set to "ngutra" corresponding to the NG RAN. In addition, the MobilityFromEUTRACommand message includes a targetRAT-MessageContainer. The targetRAT-MessageContainer contains the RRCConnectionReconfigurationNR message generated by the target NR NB 3. In addition, in the case where the targetRAT-Type is "OTHERRAN" (i.e., "utra", "geran" or "ngutra"), the MobilityFromEUTRACommand message includes nas-SecurityParamFromEUTRA.

[0186] Fig.16FIG. 4 shows a handover required message (eg, Figure 3A The handover requirement message includes a handover type set to "LTE to NR" and a source to target transparent container.

[0187] Fig.17 FIG. 4 shows a handover required message (eg, a handover required message) sent from the LTE eNB 2 to a control node (eg, a common control plane NF (CCNF)) in the NG core 5 over the NG2 interface. Figure 4A The handover request message includes a handover type set to "LTEtoNR" and a source to target transparent container. In addition, the handover request message includes a CCNF UE NG2AP ID and an eNB UE NG2AP ID. The CCNF UE NG2AP ID is an identifier assigned by a control node (e.g., CCNF) in the NG core 5 to identify UE 1 on the NG2 interface. The eNB UE NG2AP ID is an identifier assigned by the LTE eNB 2 to identify UE 1 on the NG2 interface.

[0188] Figures 18 to 20 Several examples of the format of the source NR NB to target NR NB transparent container contained in the handover request message are shown. Fig.18 In the example shown, the source NR NB to target NR NB transparent container includes an RRC container and a NextGen (NG)-RAB information list. The RRC container includes an RRC handover preparation information message. The NG-RAB information list indicates a list of radio access bearers (e.g., NG-RABs) to be handed over from the LTE eNB 2 to the NR NB 3. In the case where the NG system including the NR NB 3 and the NG core 5 is configured to support bearer-based delivery using bearers for each QoS level and for each PDU session, the bearer-based delivery can be used. Fig.18 The format shown. A bearer may be configured between a pair of network functions (NFs), for example, between a user plane function in the NR NB 3 and the NG core 5, or between two user plane functions in the NG core 5. A bearer in an NG system may be referred to as an NG-EPS bearer, and a radio access bearer in an NG system may be referred to as an NG-RAB.

[0189] like Fig.18 As is the case, Fig.19 The source NR NB to target NR NB transparent container shown includes an RRC container and a NG-RAB information list. Fig.19The NG-RAB information list shown includes a flow information list indicating a list of packet flows (e.g., PDU flows) mapped to each NG-RAB. In the case where the NG system including the NR NB 3 and the NG core 5 is configured to support bearer-based transmission using bearers for each QoS level and for each PDU session, and to identify packet flows (e.g., PDU flows) in the bearer to perform QoS processing (e.g., packet discard) on a per-data flow basis (e.g., on a per-PDU flow basis), the NG-RAB information list may be used. Fig.19 The format shown.

[0190] Fig. 20 The source NR NB to target NR NB transparent container shown may include either or both of a session information list and an NG-RAB information list. In the case where the NG system including the NR NB 3 and the NG Core 5 supports both bearer-based transmission and flow-based transmission, the Fig. 20 In addition, in the case where the NG system including the NR NB 3 and the NG Core 5 supports only stream-based delivery, the Fig. 20 The format shown.

[0191] Fig.21 FIG. 4 shows a (NR) handover request message (eg, Figure 3A Step 305 and Figure 4A The (NR) handover request message includes a CCNF UE NG2AP ID. The CCNF UE NG2AP ID is an identifier assigned by the control node (CCNF) in the NG core 5 to identify the UE 1 on the NG2 interface. Note that CCNF is merely an example. That is, instead of CCNF, the names of other control plane network functions or nodes (e.g., CNF, CPF, SMF, and MMF) may be used. The (NR) handover request message also includes a security context and NAS security parameters to the NG-UTRAN. The security context indicates, for example, a next hop parameter (NH) and a next hop chain counter parameter (NCC). In the case of a handover from E-UTRAN to NG RAN (NG-UTRAN), the NAS security parameters to the NG-UTRAN are included in the (NR) handover request message. The security context and the NAS security parameters to the NG-UTRAN may be configured for each network slice.

[0192] In addition, Fig.21In the example shown, the (NR) handover request message includes a list of NG-RABs to be set up. The list of NG-RABs to be set up indicates a list of radio access bearers (e.g., NG-RABs) that should be set up in the target NR NB 3. In the case where the NG system including the NR NB 3 and the NG core 5 is configured to support bearer-based transport using bearers for each QoS level and for each PDU session, the NG-RAB list may be used. Fig.21 The format shown.

[0193] Fig. 22 FIG. 4 shows a variation of the (NR) handover request message. Fig. 22 In the example shown, Fig.21 As in the case of , the (NR) Handover Request message includes a list of NG-RABs to be set. However, Fig. 22 The NG-RAB list to be set shown includes a flow information list indicating a list of packet flows (e.g., PDU flows) mapped to each NG-RAB. In the case where the NG system including the NR NB 3 and the NG core 5 is configured to support bearer-based transmission using bearers for each QoS level and for each PDU session, and to identify packet flows (e.g., PDU flows) in the bearer to perform QoS processing (e.g., packet discard) on a per-data flow basis (e.g., on a per-PDU flow basis), the NG-RAB list can be used. Fig. 22 The format shown.

[0194] Fig.23 Another variation of the (NR) handover request message is shown. Fig.23 The (NR) handover request message shown may include either or both of a list of sessions to be set up and a list of NG-RABs to be set up. The list of sessions to be set up includes information related to one or more sessions of the UE 1 to be switched. For example, the list of sessions to be set up includes slice information for each session. Fig.23 The slice information shown corresponds to the slice information described in the above embodiment. In addition, the list of sessions to be set includes a session endpoint identifier (SEID) for each session. In the case where the NG system including the NR NB 3 and the NG core 5 supports both bearer-based transmission and stream-based transmission, the NG system can be used. Fig.23 In addition, in the case where the NG system including the NR NB 3 and the NG Core 5 supports only stream-based delivery, the Fig.23 The format shown.

[0195] Fig.24An example of the format of slice information is shown. As described in detail in the first embodiment, the slice information includes an identifier of the network slice determined (or selected) for UE 1 (i.e., a network slice instance ID) and an identifier of a network function or node associated with the network slice (i.e., a network function ID). The slice information may include type information of the network slice (i.e., a multidimensional descriptor). In addition, the slice information may include a mobility level or a session level or both.

[0196] Fig.25 An example of the format of a session endpoint ID is shown. As described in detail in the first embodiment, the session endpoint ID may be a GTP-TEID, a GRE-TEID, or an identifier of a network function or node (NF ID).

[0197] Fig.26 FIG. 4 shows a (NR) handover request confirmation message (eg, Figure 3A Step 306 and Figure 4A The (NR) handover request confirmation message includes a target-to-source transparent container. The target-to-source transparent container contains the radio resource configuration information (e.g., radio parameters) generated by the target NR NB 3. Fig. 27 As shown, the target to source transparent container may include an RRC container including an RRC NG-UTRA handover command message.

[0198] In addition, Fig.26 In the example shown, the (NR) Handover Request Confirmation message includes an accepted NG-RAB list. The accepted NG-RAB list indicates a list of radio access bearers (NG-RABs) for which resources are prepared in the target cell. In the case where the NG system including the NR NB 3 and the NG Core 5 is configured to support bearer-based transport using bearers for each QoS level and for each PDU session, the NG-RAB list may be used. Fig.26 The format shown.

[0199] Fig.28 FIG. 2 shows a variation of the (NR) handover request confirmation message. Fig.28 In the example shown, Fig.26 As in the case of , the (NR) Handover Request Ack message includes the list of accepted NG-RABs. Fig.28The admitted NG-RAB list shown includes a flow information list indicating a list of packet flows (e.g., PDU flows) mapped to each NG-RAB. In the case where the NG system including the NR NB 3 and the NG core 5 is configured to support bearer-based transmission using bearers for each QoS level and for each PDU session, and to identify packet flows (e.g., PDU flows) in the bearer for QoS processing (e.g., packet discard) on a per-data flow basis (e.g., on a per-PDU flow basis), the NG-RAB list may be used. Fig.28 The format shown.

[0200] Fig.29 Another variation of the (NR) Handover Request Confirmation message is shown. Fig.29 The (NR) handover request confirmation message shown may include either or both of an admitted session list and an admitted NG-RAB list. The admitted session list includes information about one or more sessions of UE 1 for which resources have been prepared in the target cell. In the case where the NG system including the NR NB 3 and the NG core 5 supports both bearer-based transmission and flow-based transmission, the Fig.29 In addition, in the case where the NG system including the NR NB 3 and the NG Core 5 supports only stream-based delivery, the Fig.29 The format shown.

[0201] Fig.30 Show Fig.29 An example of the format of the forwarding address is shown. The forwarding address includes either or both of the information used for downlink data forwarding (ie, DL transport layer address and DL session endpoint ID) and the information used for uplink data forwarding (ie, UL transport layer address and UL session endpoint ID).

[0202] Fig.31 FIG. 4 shows an S1AP handover command message (eg, Figure 3B The example of the format of step 308 of the handover command message. The handover command message includes a list of E-RABs as the object of forwarding. The list of E-RABs as the object of forwarding indicates the E-RABs as the object of data forwarding.

[0203] In addition, in the case of a handover from E-UTRAN to "OTHER RAN", in other words when the Handover Type IE is set to "LTEtoNR (or LTEtoNGUTRAN)", "LTEtoUTRAN" or "LTEtoGERAN", the S1AP Handover Command message includes NAS security parameters from E-UTRAN. The NAS security parameters from E-UTRAN include security-related information used for inter-RAT handover from E-UTRAN.

[0204] Fig.32 FIG. 4 shows an NG2AP handover command message (eg, CCNF) sent from a control node (eg, CCNF) in the NG core 5 to the LTE eNB 2 over the NG2 interface. Figure 4B The example of the format of step 406 of the handover command message is shown in FIG. 4. The handover command message includes a list of NE-RABs as objects of forwarding. The list of NE-RABs as objects of forwarding indicates a NextGen E-RAB as an object of data forwarding. Note that the NextGen E-RAB (e.g., NE-RAB) is an E-RAB set up between the UE and the user plane function (e.g., CUNF) in the NG core 5 via an eLTE eNB enhanced to support an interface with the NG core.

[0205] Other embodiments

[0206] Each of the above embodiments may be used alone, or two or more of these embodiments may be appropriately combined with each other.

[0207] The E-URAN and NG RAN described in the above embodiments can be implemented based on the concept of cloud radio access network (C-RAN). C-RAN is also called centralized RAN. In this case, the processing and operations performed by the LTE eNB 2 and NR NB 3 described in the above embodiments can be provided by a digital unit (DU) included in the C-RAN architecture, or by a combination of a DU and a radio unit (RU). DU is also called a baseband unit (BBU) or a central unit (CU). RU is also called a remote radio head (RRH), a remote radio equipment (RRE) or a distributed unit (DU). DU and RU can provide these functions by dividing the functions of the AS layer provided in the entire RAN into functions provided by the DU and functions provided by the RU. For example, DU and RU can be provided by the following structure: a part of the AS layer (e.g., layer 2 / layer 3 or its sublayer, or a part of the function of the layer) is arranged in the DU, and the remaining layers (or the rest of the layers) are arranged in the RU. That is, the processing and operations performed by the LTE eNB 2 and NR NB 3 described in the above embodiments can be provided by one or more wireless stations (or RAN nodes).

[0208] NR NB 3 may be configured to dynamically change the allocation of the AS layer or its functions to the DU and RU. In other words, NR NB3 may be configured to dynamically change the split point of the AS layer or its functions between the DU and the RU. For example, NR NB 3 may be configured to dynamically select one of a plurality of different functional split options. In this case, in the HO process from LTE to NR in the above-mentioned embodiment, the NG core 5 may determine the allocation of the AS layer or its functions to the DU and RU of NR NB 3 in response to receiving a forwarding relocation request message or a switching requirement message. Alternatively, NR NB 3 may determine the allocation of the AS layer or its functions to the DU and RU of NR NB3. The NG core 5 or NR NB 3 may select a functional split option to be applied to NR NB3 from a plurality of predetermined functional split options.

[0209] In the example, the functional split option to be applied to NR NB 3 can be determined (or selected) based on the E-RAB QoS information IE (e.g., QCI or ARP) or flow information included in the forwarding relocation request message or the handover requirement message. Additionally or optionally, the functional split option to be applied to NR NB 3 can be determined based on the slice created by the NG core 5 or NR NB 3 or information related to the slice (slice information). Additionally or optionally, the functional split option to be applied to NR NB 3 can be determined based on the network slice assistance information included in the NAS information sent from UE 1.

[0210] In addition, in the above embodiment, the UE identifier may be included in the message transmitted between nodes. The UE identifier is used to identify the UE 1 to be handed over during the handover process.

[0211] More specifically, the UE identifier may be a UE identifier used on an interface (e.g., Sn interface or NG2 interface, n is an integer) between the NR NB 3 and a control node corresponding to the MME and included in the NG Core 5. The UE identifier may be represented as an NR NB UE SnAP ID (NR NB UE Sn Application Protocol Identifier) ​​or an NR NB UE NG2AP ID.

[0212] Alternatively, the UE identifier may be a UE identifier used on an interface (e.g., Xn interface, n is an integer) between the NR NB 3 and the LTE eNB 2. The UE identifier may be represented as NR NB UE XnAP ID.

[0213] Alternatively, the UE identifier may be a UE identifier used on an interface (eg, Sm interface, m is an integer) between an MME in EPC 4 and a control node corresponding to the MME and included in NG Core 5. The UE identifier may be represented as eMME UE SmAP ID.

[0214] Alternatively, the UE identifier may be a UE identifier that is used on an interface (e.g., S1 interface, where l is an integer) between the LTE eNB 2 and a control node corresponding to the MME and included in the NG core 5 and is allocated by the control node. The UE identifier may be represented as an eMME UE S1AP ID.

[0215] Furthermore, these UE identifiers may be transmitted between nodes during a handover process. Note that Sn, NG2, Sm, S1, and Xn used to identify the respective interfaces are merely examples and may be represented by different symbols.

[0216] In addition, the above-described embodiments are merely examples of application of the technical ideas obtained by the present inventors. These technical ideas are not limited to the above-described embodiments, and various modifications can be made to these technical ideas.

[0217] For example, all or part of the embodiments disclosed above may be described as, but not limited to, the following supplementary descriptions.

[0218] (Supplementary Note 1)

[0219] A target radio access network node, namely a target RAN node, is associated with an unbearable network, and the target RAN node includes:

[0220] at least one memory; and

[0221] at least one processor connected to the at least one memory and configured to:

[0222] receiving, from a core network, a handover request message for requesting handover of a wireless terminal from a bearer-based network to the bearerless network, the handover request message including flow information about at least one session to be established in the bearerless network for transmitting at least one packet flow of the wireless terminal; and

[0223] In response to the handover request message, a handover request confirmation message including a target-to-source transparent container is sent to the core network, wherein the target-to-source transparent container includes radio resource configuration information derived from the flow information, and the target-to-source transparent container is to be forwarded via the core network to a source RAN node associated with the bearer-based network.

[0224] (Supplementary Note 2)

[0225] The target RAN node according to Supplementary Note 1, wherein the wireless resource configuration information includes information indicating mapping between bearers used by wireless terminals used in the bearer-based network and at least one packet flow used by wireless terminals used in the bearerless network.

[0226] (Supplementary Note 3)

[0227] The target RAN node according to Supplementary Note 1 or 2, wherein the flow information includes a flow identifier and a flow QoS parameter for each packet flow of the wireless terminal.

[0228] (Supplementary Note 4)

[0229] A source radio access network node, namely a source RAN node, is associated with a bearer-based network, the source RAN node comprising:

[0230] at least one memory; and

[0231] at least one processor connected to the at least one memory and configured to:

[0232] Sending a handover request message for starting handover of the wireless terminal from the bearer-based network to the bearer-free network to the core network;

[0233] receiving, from the core network, a handover command message including a target-to-source transparent container, the target-to-source transparent container being generated by a target RAN node associated with the bearerless network and including radio resource configuration information required by the wireless terminal to establish a radio connection, the radio connection being associated with at least one session to be established in the bearerless network for transmitting at least one packet flow of the wireless terminal; and

[0234] A mobility command message including the radio resource configuration information and instructing switching to the bearerless network is sent to the wireless terminal.

[0235] (Supplementary Note 5)

[0236] The source RAN node according to Supplementary Note 4, wherein the wireless resource configuration information includes information indicating mapping between bearers used by wireless terminals used in the bearer-based network and at least one packet flow used by wireless terminals used in the bearerless network.

[0237] (Supplementary Note 6)

[0238] A source RAN node according to Supplementary Note 4 or 5, wherein the handover command message includes either or both of an address and an endpoint identifier allocated for data forwarding of each packet flow in at least one packet flow to be transmitted via a bearer used by a wireless terminal used in the bearer-based network, and an identifier of each packet flow.

[0239] (Supplementary Note 7)

[0240] The source RAN node according to Supplementary Note 6, wherein the at least one processor is configured to perform data forwarding of the at least one packet flow based on either or both of the address and the endpoint identifier, and by using an identifier of each packet flow in the at least one packet flow.

[0241] (Supplementary Note 8)

[0242] A wireless terminal, comprising:

[0243] at least one memory; and

[0244] at least one processor connected to the at least one memory and configured to:

[0245] receiving, from a radio access network node (RAN node) associated with a bearer-based network, a mobility command message indicating a handover from the bearer-based network to an unbearable network, the mobility command message being generated by a target RAN node associated with the unbearable network and comprising radio resource configuration information required by the wireless terminal to establish a radio connection associated with at least one session to be established in the unbearable network for transmitting at least one packet flow of the wireless terminal; and

[0246] The radio connection is established with the target RAN node associated with the unhosted network by using the radio resource configuration information.

[0247] (Supplementary Note 9)

[0248] The wireless terminal according to Supplementary Note 8, wherein the wireless resource configuration information includes information indicating mapping between a bearer used by the wireless terminal used in the bearer-based network and at least one packet flow used by the wireless terminal used in the bearerless network.

[0249] (Supplementary Note 10)

[0250] A method in a target radio access network node, i.e., a target RAN node, wherein the target RAN node is associated with an unbearable network, the method comprising:

[0251] receiving, from a core network, a handover request message for requesting handover of a wireless terminal from a bearer-based network to the bearerless network, the handover request message including flow information about at least one session to be established in the bearerless network for transmitting at least one packet flow of the wireless terminal; and

[0252] In response to the handover request message, a handover request confirmation message including a target-to-source transparent container is sent to the core network, wherein the target-to-source transparent container includes radio resource configuration information derived from the flow information, and the target-to-source transparent container is to be forwarded via the core network to a source RAN node associated with the bearer-based network.

[0253] (Supplementary Note 11)

[0254] A method in a source radio access network node, i.e., a source RAN node, the source RAN node being associated with a bearer-based network, the method comprising:

[0255] Sending a handover request message for starting handover of the wireless terminal from the bearer-based network to the bearer-free network to the core network;

[0256] receiving, from the core network, a handover command message including a target-to-source transparent container, the target-to-source transparent container being generated by a target RAN node associated with the bearerless network and including radio resource configuration information required by the wireless terminal to establish a radio connection, the radio connection being associated with at least one session to be established in the bearerless network for transmitting at least one packet flow of the wireless terminal; and

[0257] A mobility command message including the radio resource configuration information and instructing switching to the bearerless network is sent to the wireless terminal.

[0258] (Supplementary Note 12)

[0259] A method in a wireless terminal, the method comprising:

[0260] receiving, from a radio access network node (RAN node) associated with a bearer-based network, a mobility command message indicating a handover from the bearer-based network to an unbearable network, the mobility command message being generated by a target RAN node associated with the unbearable network and comprising radio resource configuration information required by the wireless terminal to establish a radio connection associated with at least one session to be established in the unbearable network for transmitting at least one packet flow of the wireless terminal; and

[0261] The radio connection is established with the target RAN node associated with the unhosted network by using the radio resource configuration information.

[0262] (Supplementary Note 13)

[0263] A non-transitory computer-readable medium storing a program for causing a computer to perform a method in a target radio access network node, i.e., a target RAN node, the target RAN node being associated with an unhosted network, wherein the method comprises:

[0264] receiving, from a core network, a handover request message for requesting handover of a wireless terminal from a bearer-based network to the bearerless network, the handover request message including flow information about at least one session to be established in the bearerless network for transmitting at least one packet flow of the wireless terminal; and

[0265] In response to the handover request message, a handover request confirmation message including a target-to-source transparent container is sent to the core network, wherein the target-to-source transparent container includes radio resource configuration information derived from the flow information, and the target-to-source transparent container is to be forwarded via the core network to a source RAN node associated with the bearer-based network.

[0266] (Supplementary Note 14)

[0267] A non-transitory computer-readable medium storing a program for causing a computer to perform a method in a source radio access network node, i.e., a source RAN node, the source RAN node being associated with a bearer-based network, wherein the method comprises:

[0268] Sending a handover request message for starting handover of the wireless terminal from the bearer-based network to the bearer-free network to the core network;

[0269] receiving, from the core network, a handover command message including a target-to-source transparent container, the target-to-source transparent container being generated by a target RAN node associated with the bearerless network and including radio resource configuration information required by the wireless terminal to establish a radio connection, the radio connection being associated with at least one session to be established in the bearerless network for transmitting at least one packet flow of the wireless terminal; and

[0270] A mobility command message including the radio resource configuration information and instructing switching to the bearerless network is sent to the wireless terminal.

[0271] (Supplementary Note 15)

[0272] A non-transitory computer-readable medium storing a program for causing a computer to perform a method in a wireless terminal, wherein the method comprises:

[0273] receiving, from a radio access network node (RAN node) associated with a bearer-based network, a mobility command message indicating a handover from the bearer-based network to an unbearable network, the mobility command message being generated by a target RAN node associated with the unbearable network and comprising radio resource configuration information required by the wireless terminal to establish a radio connection associated with at least one session to be established in the unbearable network for transmitting at least one packet flow of the wireless terminal; and

[0274] The radio connection is established with the target RAN node associated with the unhosted network by using the radio resource configuration information.

[0275] This application is based upon and claims the benefit of priority from Japanese patent application No. 2016-158279, filed on August 10, 2016, the entire contents of which are incorporated herein by reference.

[0276] Description of Reference Numerals

[0277] 1 User Equipment (UE)

[0278] 2 LTE eNodeB (eNB)

[0279] 3 New Radio (NR) Node B (NB)

[0280] 4 Evolved Packet Core (EPC)

[0281] 5 NextGen (NG) Core

[0282] 1105 Baseband Processor

[0283] 1106 Application Processor

[0284] 1108 Memory

[0285] 1204 Processor

[0286] 1205 Memory

[0287] 1304 Processor

[0288] 1305 Memory

[0289] 1402 Processor

[0290] 1403 Memory

Claims

1. A target radio access network node, i.e., a target RAN node, configured to be connected to a fifth generation core network, i.e., a 5G core network, wherein the target RAN node comprises: at least one memory; as well as at least one processor connected to the at least one memory and configured to: receiving, from the 5G core network, a handover request message requesting a handover of a wireless terminal from a source RAN node connected to the 5G core network to the target RAN node, the handover request message comprising flow information and slice information, the flow information being related to at least one PDU session to be established in the 5G core network for transmitting at least one packet flow of the wireless terminal, the flow information comprising a flow identifier and a flow quality of service parameter, i.e., a flow QoS parameter, for each packet flow of the PDU session; as well as In response to the handover request message, sending a handover request confirmation message to the 5G core network, the handover request confirmation message including a target-to-source transparent container to be forwarded to the source RAN node, the target-to-source transparent container including radio resource configuration information derived from the flow information or from the slice information, wherein the slice information identifies a network slice corresponding to the PDU session, The slice information includes information indicating a service type of the network slice, and The network slice is a logical network.

2. The target RAN node according to claim 1, wherein: The wireless resource configuration information is generated based on at least one information included in the flow information.

3. The target RAN node according to claim 1 or 2, wherein: The radio resource configuration information is required by the wireless terminal to establish a radio connection associated with the at least one PDU session in order to transmit at least one flow of the wireless terminal.

4. The target RAN node according to claim 1 or 2, wherein: The flow information also includes priority information indicating a relative priority order among the plurality of packet flows.

5. The target RAN node according to claim 1 or 2, wherein: The flow information includes information indicating a mapping between a bearer for the wireless terminal and at least one packet flow for the wireless terminal.

6. A source radio access network node, i.e., a source RAN node, configured to be connected to a fifth generation core network, i.e., a 5G core network, the source RAN node comprising: at least one memory; as well as at least one processor connected to the at least one memory and configured to: sending a handover request message to the 5G core network for initiating handover of the wireless terminal from the source RAN node to a target RAN node connected to the 5G core network; receiving, from the 5G core network, a handover command message including a target-to-source transparent container, the target-to-source transparent container being generated by the target RAN node and forwarded to the source RAN node via the 5G core network, the target-to-source transparent container comprising radio resource configuration information derived by the target RAN node from flow information or slice information received by the target RAN node from the 5G core network via a handover request message, the flow information relating to at least one PDU session to be established in the 5G core network for transmitting at least one packet flow of the wireless terminal and comprising a flow identifier and a flow quality of service parameter, i.e., a flow QoS parameter, for each packet flow of the PDU session; and sending a message including the wireless resource configuration information and indicating the handover to the wireless terminal, wherein the slice information identifies a network slice corresponding to the PDU session, The slice information includes information indicating a service type of the network slice, and The network slice is a logical network.

7. The source RAN node according to claim 6, wherein: The radio resource configuration information is generated based on at least one information included in the flow information.

8. A wireless terminal, comprising: at least one memory; as well as at least one processor connected to the at least one memory and configured to: receiving a message from a source radio access network node, i.e., a source RAN node, connected to a fifth generation core network, i.e., a 5G core network, the message comprising radio resource configuration information and indicating a handover from the source RAN node to a target RAN node connected to the 5G core network, the radio resource configuration information being derived by the target RAN node from flow information or slice information received by the target RAN node from the 5G core network via a handover request message, the flow information being related to at least one PDU session to be established in the 5G core network for transmitting at least one packet flow of the wireless terminal and comprising a flow identifier and a flow quality of service parameter, i.e., a flow QoS parameter, for each packet flow of the PDU session; as well as establishing a wireless connection with the target RAN node by using the wireless resource configuration information, wherein the slice information identifies a network slice corresponding to the PDU session, The slice information includes information indicating a service type of the network slice, and The network slice is a logical network.

9. The wireless terminal according to claim 8, wherein: The wireless resource configuration information is generated based on at least one information included in the flow information.

10. A fifth generation core network node, i.e., a 5G core network node, configured to be used in a 5G core network, the 5G core network node comprising: at least one memory; as well as at least one processor connected to the at least one memory and configured to: receiving, from a source radio access network node, i.e., a source RAN node, connected to the 5G core network, a handover request message instructing a wireless terminal to hand over from the source RAN node to a target RAN node connected to the 5G core network; In response to receiving the handover requirement message, sending a handover request message to the target RAN node, the handover request message including flow information and slice information, the flow information being related to at least one PDU session to be established in the 5G core network for transmitting at least one packet flow of the wireless terminal, the flow information including a flow identifier and a flow quality of service parameter, i.e., a flow QoS parameter, for each packet flow of the PDU session; receiving a handover request confirmation message from the target RAN node after sending the handover request message, wherein the handover request confirmation message includes a target-to-source transparent container to be forwarded to the source RAN node, the target-to-source transparent container including radio resource configuration information derived by the target RAN node from the flow information or from the slice information; and sending a handover command message including the target to source transparent container to the source RAN node, wherein the slice information identifies a network slice corresponding to the PDU session, The slice information includes information indicating a service type of the network slice, and The network slice is a logical network.

11. The core network node according to claim 10, wherein: The radio resource configuration information is generated based on at least one information included in the flow information.

12. A method in a target radio access network node, i.e. a target RAN node, wherein the target RAN node is configured to be connected to a fifth generation core network, i.e. a 5G core network, the method comprising: receiving, from the 5G core network, a handover request message requesting a handover of a wireless terminal from a source RAN node connected to the 5G core network to the target RAN node, the handover request message comprising flow information and slice information, the flow information being related to at least one PDU session to be established in the 5G core network for transmitting at least one packet flow of the wireless terminal, the flow information comprising a flow identifier and a flow quality of service parameter, i.e., a flow QoS parameter, for each packet flow of the PDU session; as well as In response to the handover request message, sending a handover request confirmation message to the 5G core network, the handover request confirmation message including a target-to-source transparent container to be forwarded to the source RAN node, the target-to-source transparent container including radio resource configuration information derived from the flow information or from the slice information, wherein the slice information identifies a network slice corresponding to the PDU session, The slice information includes information indicating a service type of the network slice, and The network slice is a logical network.

13. A method in a source radio access network node, i.e., a source RAN node, wherein the source RAN node is configured to be connected to a fifth generation core network, i.e., a 5G core network, the method comprising: sending a handover request message to the 5G core network for initiating handover of the wireless terminal from the source RAN node to a target RAN node connected to the 5G core network; receiving, from the 5G core network, a handover command message including a target-to-source transparent container, the target-to-source transparent container being generated by the target RAN node and forwarded to the source RAN node via the 5G core network, the target-to-source transparent container comprising radio resource configuration information derived by the target RAN node from flow information or slice information received by the target RAN node from the 5G core network via a handover request message, the flow information relating to at least one PDU session to be established in the 5G core network for transmitting at least one packet flow of the wireless terminal and comprising a flow identifier and a flow quality of service parameter, i.e., a flow QoS parameter, for each packet flow of the PDU session; and sending a message including the wireless resource configuration information and indicating the handover to the wireless terminal, wherein the slice information identifies a network slice corresponding to the PDU session, The slice information includes information indicating a service type of the network slice, and The network slice is a logical network.

14. A method in a wireless terminal, the method comprising: receiving a message from a source radio access network node, i.e., a source RAN node, connected to a fifth generation core network, i.e., a 5G core network, the message comprising radio resource configuration information and indicating a handover from the source RAN node to a target RAN node connected to the 5G core network, the radio resource configuration information being derived by the target RAN node from flow information or slice information received by the target RAN node from the 5G core network via a handover request message, the flow information being related to at least one PDU session to be established in the 5G core network for transmitting at least one packet flow of the wireless terminal and comprising a flow identifier and a flow quality of service parameter, i.e., a flow QoS parameter, for each packet flow of the PDU session; as well as establishing a wireless connection with the target RAN node by using the wireless resource configuration information, wherein the slice information identifies a network slice corresponding to the PDU session, The slice information includes information indicating a service type of the network slice, and The network slice is a logical network.

15. A method in a fifth generation core network node, i.e., a 5G core network node, wherein the 5G core network node is configured for use in a 5G core network, the method comprising: receiving, from a source radio access network node, i.e., a source RAN node, connected to the 5G core network, a handover request message instructing a wireless terminal to hand over from the source RAN node to a target RAN node connected to the 5G core network; In response to receiving the handover requirement message, sending a handover request message to the target RAN node, the handover request message including flow information and slice information, the flow information being related to at least one PDU session to be established in the 5G core network for transmitting at least one packet flow of the wireless terminal, the flow information including a flow identifier and a flow quality of service parameter, i.e., a flow QoS parameter, for each packet flow of the PDU session; receiving a handover request confirmation message from the target RAN node after sending the handover request message, wherein the handover request confirmation message includes a target-to-source transparent container to be forwarded to the source RAN node, the target-to-source transparent container including radio resource configuration information derived from the flow information or from the slice information; and sending a handover command message including the target to source transparent container to the source RAN node, wherein the slice information identifies a network slice corresponding to the PDU session, The slice information includes information indicating a service type of the network slice, and The network slice is a logical network.

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