Patent Description:
3rd Generation Partnership Project (3GPP) specifies Long Term Evolution (LTE), and with an aim of further speeding, specifies LTE-Advanced (hereinafter, it is assumed that <NUM> includes the LTE-Advanced). Moreover, in the 3GPP, specifications of a successor system of the LTE (hereinafter, referred to as <NUM>) called <NUM> New Radio (NR) and the like are being studied.

The specifications of such <NUM> also include inter-work between <NUM> and <NUM>, for example, handover of a user device (User Equipment, UE) between <NUM> and <NUM>. In the inter-system handover between <NUM> (specifically Evolved Packet Core (EPC)) and <NUM> (specifically <NUM> Core (5GC)), a mapping between PDN connection set in the EPC and PDU session set in the 5GC is necessary.

Specifically, a mapping between an EPS bearer related to the PDN connection and a QoS flow related to the PDU session is necessary.

Moreover, when the UE performs handover from <NUM> to <NUM>, it is necessary that the content of a traffic flow template (TFT), which is a list of filters of a traffic flow (IP flow) associated with the EPS bearer, is reflected in a QoS rule associated with the QoS flow of the handover destination. That is, it is necessary that the UE and EPC-5GC recognize filtering content of similar traffic flow before and after the handover.

Therefore, when the UE performs handover from <NUM> to <NUM>, a method of associating, regardless of the content of the TFT associated with the EPS bearer, a default QoS rule with the QoS flow of the handover destination has been proposed (see Non-Patent Document <NUM>). With this method, when executing the handover, it is not necessary to exchange information between the UE and the EPC-5GC. Therefore, the handover procedure from <NUM> to <NUM> can be simplified. Furthermore, because the handover processing load is reduced, this may lead to reduction in delay.

Non-Patent Document <NUM>: "<NPL>
<NPL>) describes proposed solutions for single-registration HO from EPS to 5GS and proposes to introduce session parameters mapping in the inter-system procedures from EPS to 5GS. It proposes: use the approach proposed in S2-<NUM> as a baseline for the HO procedure from EPS to 5GS, so that changes to EPC and E-UTRAN to provide the UE with PDU session parameters are not required; during the HO procedure from EPS to 5GS, the PDU session parameters (PDU Session ID and respective QFIs) are determined independently in the UE and the SMF by deriving them from the correspondent PDN connection parameters (the PDU session ID from the default EBI and the QFIs from the EBIs, respectively) ; <NUM> QoS rule and TFT is a subset of <NUM> QoS rule and TFT; the UE continues to use the same MBR value that was assigned in EPC for the corresponding EPS GBR bearer, and if needed the network can update the MBR after the handover to 5GS has been completed; during the inter-system idle mode procedure from EPS to 5GS with Nx interface, the PDU session parameters (PDU Session ID and respective QFIs) are determined independently in the UE and the SMF by deriving them from the correspondent PDN connection parameters (the PDU session ID from the default EBI and the QFIs from the EBIs, respectively) ; during the inter-system idle mode procedure from EPS to 5GS without Nx interface, the PDU session IDs are determined independently in the UE and the SMF by deriving them from the correspondent PDN connection parameters (the PDU session ID from the default EBI. The SMF indicates the <NUM> QoS rules for the PDU sessions to the UE during the PDU session establishment procedure.

<NPL>) describes the procedure on reflective QoS deactivation. When the 5GC determine to disable an activated reflective QoS rule, the 5GC should notify the UE and UPF explicitly via C- plane. Optionally, the 5GC can implicitly notify the UE that the reflective QoS has been disabled via U-plane. The UE shall delete all derived QoS rules when the reflective QoS is disabled. <NPL>) deals with a call flow for the Single Registration-based handover from EPS to 5GS procedure. The UE does not receive a PDU Session Modification command from the SMF via MME and E-UTRAN. This is to avoid changes to the signalling in EPS and in particular to the Handover Command. The UE and the SMF derive the PDU Session ID from the corresponding Default EBI as proposed in S2-<NUM> (submitted by ZTE to SA2#<NUM>) and the QFI from the corresponding EBI. The UE and the SMF derive the <NUM> QoS flow template for each QoS flow from the EPS TFT which was assigned for the corresponding EPS bearer. The UE continues to use the same MBR value that was assigned in EPC for the corresponding EPS GBR bearer, and if needed the network can update the MBR after the handover to 5GS has been completed.

The method described in Non-Patent Document <NUM> considers a case in which a particular TFT is not associated with the EPS bearer (that is, a case in which a so-called "match all" filter is associated).

However, for example, there are situations, like in Voice over LTE (VoLTE), in which a particular TFT is associated with the EPS bearer. In such situations, if the method of associating the default QoS rule with the QoS flow of the handover destination described above is used, similar quality of service (QoS) cannot be provided to a traffic flow of the VoLTE after completion of the handover to <NUM>.

The present invention has been made in view of the above discussion. One object of the present invention is to provide a user device, a radio communication system, and a radio communication method that can autonomously reflect the content of the TFT in the QoS rule associated with the QoS flow of the handover destination even when the particular traffic flow template (TFT) is associated with the EPS bearer.

Advantageous embodiments are defined in the dependent claim.

Exemplary embodiments are explained below with reference to the accompanying drawings. In the drawings, structural elements having the same function or configuration are indicated by the same or similar reference numerals and the explanation thereof is appropriately omitted.

<FIG> is an overall structural diagram of a radio communication system <NUM> according to the present embodiment. The radio communication system <NUM> supports a plurality of radio communication schemes. Specifically, the radio communication system <NUM> is constituted by a plurality of the radio communication systems that varies in the radio communication schemes.

More specifically, as shown in <FIG>, the radio communication system <NUM> is constituted by a radio communication system in accordance with <NUM> (first radio communication system) and a radio communication system in accordance with <NUM> (second radio communication system).

The "<NUM>" is a radio communication system in accordance with Long Term Evolution (LTE), and includes an Evolved Universal Terrestrial Radio Access Network <NUM> (hereinafter, "E-UTRAN <NUM>"), a Mobility Management Entity <NUM> (hereinafter, "MME <NUM>"), a Serving Gateway <NUM> (hereinafter, "SGW <NUM>"), and the like.

The "<NUM>" is a successor system of the LTE called New Radio (NR) and the like, and includes a <NUM> Radio Access Network <NUM> (hereinafter, "<NUM> RAN <NUM>"), an Access and Mobility Management Function <NUM> (hereinafter, "AMF <NUM>"), a Session Management Function / PDN Gateway-C plane <NUM> (hereinafter, "SMF/PGW-C <NUM>"), a User Plane Function <NUM> (hereinafter, "UPF/PGW-U <NUM>"), a Unified Data Management <NUM> (hereinafter, "UDM <NUM>"), a Policy Control Function / Policy and Charging Rules Function <NUM> (hereinafter, "PCF/PCRF <NUM>"), and the like. The configuration of nodes that constitute the <NUM> shown in <FIG> is in accordance with the standards stipulated in 3GPP TS <NUM> and the like.

A Data Network <NUM> (hereinafter, "DN <NUM>") is connected to the SGW <NUM> and the UPF/PGW-U <NUM>. An IP network such as the Internet is connected to the DN <NUM>.

In <FIG>, however, only the nodes (devices) relating to the present disclosure are shown. As it can be clearly understood from the names, the SMF/PGW-C <NUM>, the UPF/PGW-U <NUM>, and the PCF/PCRF <NUM> are explained so because it is assumed that the <NUM> functions (PGW-C, PGW-U, PCRF), too, would expand in the future and develop so as to function as the <NUM>.

Moreover, the "<NUM>" can be referred to as the LTE (including LTE-Advanced), and the "<NUM>" can be referred to as the New Radio (NR) and the like. Furthermore, a node group at the <NUM> core network side excluding the E-UTRAN <NUM> can be referred to as the Evolved Packet Core (EPC). A node group at the <NUM> core network side excluding the <NUM> RAN <NUM> can be referred to as the <NUM> Core (5GC).

The E-UTRAN <NUM> includes a radio base station <NUM>. The radio base station <NUM> can be referred to as eNB (eNode B). The <NUM> RAN <NUM> includes a radio base station <NUM>. The radio base station <NUM> can be referred to as gNB (gNode B).

A user device <NUM> (hereinafter, "UE <NUM>") supports the <NUM> and the <NUM>. In other words, the UE <NUM> executes radio communication in accordance with the <NUM> with the radio base station <NUM>, and executes radio communication in accordance with the <NUM> with the radio base station <NUM>.

Moreover, the UE <NUM> performs handover between <NUM> (first radio communication system) and <NUM> (second radio communication system). In other words, the UE <NUM> can perform handover from <NUM> to <NUM> and from <NUM> to <NUM>.

Particularly, in the present embodiment, as explained later, the UE <NUM>, the EPC, and the 5GC acquire association between the EPS bearer and the QoS flow by using mapping information in which a flow identifier (QoS Flow ID) for recognizing a type of the QoS flow set in the <NUM> and a bearer identifier (EPS Bearer ID) for recognizing a type of the EPS bearer set in the <NUM> are associated. Handover is performed between the bearer and the QoS flow that are associated with each other.

Note that, the EPS Bearer ID may be abbreviated to EBI, and the QoS Flow ID may be abbreviated to QFI.

A functional block configuration of the radio communication system <NUM> is explained below. Specifically, a functional block configuration of the UE <NUM> and the SMF/PGW-C <NUM> is explained below.

<FIG> is a functional block diagram of the UE <NUM>. As shown in <FIG>, the UE <NUM> includes a radio communication unit <NUM>, a connection setting unit <NUM>, a session setting unit <NUM>, a mapping information holding unit <NUM>, a filter holding unit <NUM>, a QoS rule generating unit <NUM>, and a handover executing unit <NUM>.

The radio communication unit <NUM> performs radio communication in accordance with the <NUM> and the <NUM>. Specifically, the radio communication unit <NUM> transmits and receives radio signals to and from the radio base station <NUM> in accordance with the <NUM>. Moreover, the radio communication unit <NUM> transmits and receives radio signals to and from the radio base station <NUM> in accordance with the <NUM>.

Note that, in the present embodiment, the type of the UE <NUM> is not particularly limited. That is, the UE <NUM> can belong to the ordinary UE category, or can belong to a category for Internet of Things (IoT), specifically a category (category M1, M2) for bandwidth reduced low complexity UE (BL UE).

Furthermore, the UE <NUM> may be able to perform carrier aggregation (CA) and dual connectivity (DC).

The connection setting unit <NUM> sets Packet Data Network connection (PDN connection) with the EPC. Specifically, the connection setting unit <NUM> sets the PDN connection that goes via the EPS bearer that is a logical communication path set with the EPC. That is, the PDN connection is related (is associated) to the EPS bearer.

The session setting unit <NUM> sets Protocol Data Unit session (PDU session) with the 5GC. Specifically, the session setting unit <NUM> sets the PDU session that shows a connection relation (association) between the UE <NUM> and the DN <NUM> that provides PDN Connectivity service.

Moreover, the PDU session is related (is associated) to the QoS flow (<NUM> QoS Flow) prescribed in the 5GC. The QoS flow corresponds with a particular quality of service (QoS). A communication (traffic) assigned to the QoS flow receives the same handling with respect to scheduling, queue management, shaping, configuration of the radio link control layer (RLC), and the like of.

The mapping information holding unit <NUM> holds mapping information (association information) in which the type of the EPS bearer and the type of the QoS flow (<NUM> QoS Flow) are mapped with each other. As mentioned earlier, the EPS bearer is set in the <NUM>. Moreover, the QoS flow is set in the <NUM>, and it is prescribed depending on the particular quality of service.

The mapping information is necessary when the UE <NUM> performs handover (inter-system handover) between <NUM> and <NUM>. That is, the mapping between the EPS bearer related to the PDN connection and the QoS flow related to the PDU session becomes necessary when the UE <NUM> performs the inter-system handover.

The mapping information held in the mapping information holding unit <NUM> includes such association between the EPS Bearer ID and the QoS Flow ID. That is, the EPS Bearer ID for recognizing the type of the EPS bearer and the QoS Flow ID for recognizing the type of the QoS flow are mapped with each other in the mapping information. Note that, a detailed explanation about the mapping information is given below with reference to <FIG> and <FIG>.

The mapping information holding unit <NUM> can hold the mapping information received from the EPC or the 5GC. For example, the mapping information can be transmitted to the UE <NUM> as a message, notification information (SIB (System Information Block)), and the like of the radio resource control layer (RRC layer).

Alternatively, the mapping information can be stored beforehand in Universal Integrated Circuit Card (UICC), Universal Subscriber Identity Module (USIM), and the like of the UE <NUM>. Furthermore, the mapping information can be updated together when firmware is updated by FOTA (Firmware On-The-Air). Alternatively, the mapping information can be updated together when the operating system of the UE <NUM> is updated.

The filter holding unit <NUM> holds a filter of the traffic flow (IP flow) associated with the EPS bearer. Specifically, the filter holding unit <NUM> holds a traffic flow template (TFT) associated with the EPS bearer set for the UE <NUM> in the <NUM>.

The TFT includes Filter id (filter identifier), Precedence order (precedence), and Filter Content (filter content). The TFT may be called a filter list and the like. More information about the TFT will be given later.

The QoS rule generating unit <NUM> generates a quality-of-service rule associated with the QoS flow. Specifically, the QoS rule generating unit <NUM> autonomously generates <NUM> QoS Rule associated with the QoS flow.

More specifically, the QoS rule generating unit <NUM> generates the <NUM> QoS Rule associated with a particular QoS flow (<NUM> QoS Flow) based on the EBI (bearer identifier) for recognizing the type of the EPS bearer and the filter (TFT) held by the filter holding unit <NUM>.

As mentioned earlier, because the association between the EPS bearer and the QoS flow can be identified based on the mapping information held in the mapping information holding unit <NUM>, the QoS rule generating unit <NUM> can derive the <NUM> QoS Rule associated with the EPS bearer set by the UE <NUM> and generate the QoS flow.

A timing at which the QoS rule generating unit <NUM> generates the <NUM> QoS Rule is not particularly limited. For example, the QoS rule generating unit <NUM> can generate the <NUM> QoS Rule when the handover of the UE <NUM> is performed by the handover executing unit <NUM>.

Specifically, as explained below, the QoS rule generating unit <NUM> can generate the <NUM> QoS Rule at a timing (see <FIG>) when the UE <NUM> sets the radio bearer with the <NUM> RAN <NUM>, a timing (see <FIG>) at which the UE <NUM> transmits Handover Complete.

Moreover, the QoS rule generating unit <NUM> can generate Rule id (rule identifier) for recognizing the <NUM> QoS Rule based on the EBI and the Filter id (filter identifier) for recognizing the filter (TFT). A specific method for generating the <NUM> QoS Rule including the Rule id will be explained later.

The handover executing unit <NUM> performs intra-system handover of the UE <NUM> and the inter-system handover of the UE <NUM>. That is, the handover executing unit <NUM> performs the handover from <NUM> to <NUM> and the handover from <NUM> to <NUM>.

Particularly, in the present embodiment, the handover executing unit <NUM> performs the inter-system handover between <NUM> and <NUM> by using the mapping information held by the mapping information holding unit <NUM>.

When the UE <NUM> performs the inter-system handover between <NUM> and <NUM>, the handover executing unit <NUM> acquires, by using the mapping information, the association between the EPS bearer set by the UE <NUM> and the QoS flow set by the UE <NUM>. Furthermore, the handover executing unit <NUM> performs, based on the acquired association, the handover between the mutually associated EPS bearer and the QoS flow.

Specifically, the handover executing unit <NUM> performs the handover in accordance with interworking procedures prescribed in 3GPP TS <NUM> Section <NUM> (System interworking procedures with EPS).

Moreover, after performing the handover, that is, after performing the inter-system handover between <NUM> and <NUM>, until the QoS flow set with the 5GC is released (that is, including making handover back to <NUM>), the handover executing unit <NUM> can hold the acquired association between the EPS bearer and the QoS flow and the <NUM> QoS Rule generated based on the EBI and the filter (TFT).

Furthermore, even the SMF/PGW-C <NUM> can hold this association (and the <NUM> QoS Rule) until the QoS flow is released. Accordingly, the UE <NUM> and the SMF/PGW-C <NUM> can readily refer to this acquired association between the EPS bearer and the QoS flow when the need arises.

<FIG> is a functional block diagram of the SMF/PGW-C <NUM>. As shown in <FIG>, the SMF/PGW-C <NUM> includes a connection controlling unit <NUM>, a session controlling unit <NUM>, a mapping information holding unit <NUM>, a mapping information managing unit <NUM>, a filter acquiring unit <NUM>, and a QoS rule generating unit <NUM>.

The connection controlling unit <NUM> performs a control of the PDN connection set with the UE <NUM>. Specifically, the connection controlling unit <NUM> performs setting, releasement, and the like of the PDN connection while cooperating with other nodes (MME <NUM>, AMF <NUM>, and the like) that constitute the EPC or the 5GC.

The session controlling unit <NUM> performs a control of the PDU session set with the UE <NUM>. Specifically, the session controlling unit <NUM> performs setting, releasement, and the like of the PDU session while cooperating with other nodes (AMF <NUM> and the like) that constitute the EPC or the 5GC.

The mapping information holding unit <NUM> holds the same mapping information (association information) as the mapping information held by the UE <NUM>. That is, the mapping information holding unit <NUM> holds the mapping information in which the type of the EPS bearer and the type of the QoS flow are mapped with each other.

Moreover, the mapping information holding unit <NUM> can hold the mapping information generated or updated by the mapping information managing unit <NUM>.

The mapping information managing unit <NUM> manages the mapping information (association information) in which the type of the EPS bearer and the type of the QoS flow are mapped with each other. Specifically, the mapping information managing unit <NUM> generates the mapping information based on information supplied by other nodes that constitute the EPC or the 5GC. Note that, the content of the specific mapping may be specified by an operator of the radio communication system <NUM>, or the content may be generated automatically based on a predetermined algorithm.

The mapping information managing unit <NUM> can cause the mapping information holding unit <NUM> to hold the generated mapping information and can transmit the same to the UE <NUM>. As mentioned earlier, the mapping information can be transmitted to the UE <NUM> in the form of the message, the notification information, and the like of the RRC layer.

The mapping information managing unit <NUM> can update the content of the mapping information based on the information supplied by other nodes that constitute the EPC or the 5GC. The mapping information managing unit <NUM> causes the mapping information holding unit <NUM> to hold the updated mapping information.

The filter acquiring unit <NUM> acquires the filter (TFT) of the traffic flow (IP flow) associated with the EPS bearer. Specifically, the filter acquiring unit <NUM> acquires the TFT associated with the EPS bearer set for the UE <NUM> in the <NUM>.

More specifically, the filter acquiring unit <NUM> acquires content (Filter id, Precedence order, and Filter Content) of the TFT by using a session administration function provided in SMF and PGW-C. The SMF and the PGW-C hold information about the EPS bearer of the <NUM> by virtue of the session administration function, and the filter acquiring unit <NUM> can acquire the Filter id, the Precedence order, and the Filter Content by using the session administration function.

The QoS rule generating unit <NUM> generates the same quality-of-service rule as the QoS rule generating unit <NUM> of the UE <NUM>. Specifically, the QoS rule generating unit <NUM> generates the <NUM> QoS Rule associated with a particular QoS flow based on the EBI of the EPS bearer and the filter (TFT) acquired by the filter acquiring unit <NUM>.

Because the association between the EPS bearer and the QoS flow can be identified based on the mapping information held in the mapping information holding unit <NUM>, in the same manner as the QoS rule generating unit <NUM>, the QoS rule generating unit <NUM> can generate the <NUM> QoS Rule for the QoS flow associated with the EPS bearer set by the UE <NUM>.

Moreover, in the same manner as the QoS rule generating unit <NUM>, the QoS rule generating unit <NUM> can generate the <NUM> QoS Rule when the handover of the UE <NUM> is performed.

The QoS rule generating unit <NUM> can generate the Rule id (rule identifier) for recognizing the <NUM> QoS Rule based on the EBI and the Filter id (filter identifier) for recognizing the filter (TFT).

An operation of the radio communication system <NUM> is explained below. Specifically, an operation performed by the UE <NUM> when performing the inter-system handover between <NUM> and <NUM> in the radio communication system <NUM> is explained below.

Note that, an operation example is explained below in which the UE <NUM> performs the handover from <NUM> to <NUM>.

When the UE <NUM> performs the inter-system procedure, such as a handover between the EPC and an idle mode (idle mode) or a connected mode (connected mode) of the 5GC, the mapping between the EPS bearer related to the PDN connection and the QoS flow related to the PDU session is necessary. The UE <NUM> can perform the inter-system handover of the UE <NUM> by using the EPS bearer and the PDU session.

In the present embodiment, the UE <NUM> holds the mapping information in which the EPS Bearer ID, for recognizing the type of the EPS bearer, and the QoS flow are mapped with each other. Specifically, the UE <NUM> holds the mapping information showing the association between the EPS Bearer ID and the QoS Flow ID. Therefore, each time the UE <NUM> performs the inter-system handover, it is not necessary to transmit to the UE <NUM> the mapping information, that is, the association between the EPS Bearer ID and the QoS Flow ID.

<FIG> shows a conceptual sequence of the inter-system handover from <NUM> to <NUM> by the UE <NUM>. As shown in <FIG>, the SMF/PGW-C <NUM> generates the mapping information based on an association rule prescribed beforehand between the EPS Bearer ID (EBI) and the QoS Flow ID (QFI) (Step S10). The SMF/PGW-C <NUM> can generate the mapping information beforehand regardless of a timing at which the inter-system handover of the UE <NUM> is performed.

The SMF/PGW-C <NUM> identifies, by using the mapping information, the QoS flow associated with the EPS bearer identified by the EBI. Furthermore, the SMF/PGW-C <NUM> generates the quality-of-service rule (<NUM> QoS Rule) associated with the QoS flow based on the filter (TFT) associated with the EPS bearer. Note that, a specific method for generating the <NUM> QoS Rule will be explained in detail later by referring to <FIG>.

As shown in <FIG>, the mapping information is constituted by an association among a plurality of predetermined EBIs and a plurality of predetermined QFIs (Default EBI => PDU session ID and EBIs => QFIs in <FIG>).

Such mapping information is supplied beforehand to the UE <NUM>, and the same is held by the UE <NUM> also. When supplying the mapping information to the UE <NUM>, as mentioned earlier, various methods can be employed, such as using the notification information and pre-installing in UICC/USIM and the like.

In this manner, when the UE <NUM> performs the inter-system handover in a state in which the mapping information has been held in the UE <NUM> beforehand, the SMF/PGW-C <NUM> transmits N2 SM Information to the AMF <NUM> (Step S20). Note that, the process procedure after Step S20 is similar to the existing sequence used to perform the inter-system handover from <NUM> to <NUM>.

The AMF <NUM> transmits and receives a handover request and reply (N2 HO req. ) to and from the <NUM> RAN <NUM> based on the N2 SM Information received from the SMF/PGW-C <NUM> (Step S30). Moreover, the AMF <NUM> transmits to the MME <NUM> Nx Relocation Response representing that the UE <NUM> is transitioning from the <NUM> to the <NUM> (Step S40).

The MME <NUM> that received the Nx Relocation Response transmits HO command to the UE <NUM> via the E-UTRAN <NUM> (Steps S50 and S60).

The UE <NUM> performs the handover to the <NUM> RAN <NUM> based on the received HO command (Step S70). The UE <NUM>, by using the mapping information held therein, determines the QFI associated with the EBI of the EPS bearer that is in the set state, that is, the EBI of the EPS bearer that is in an active state.

The UE <NUM> sets the radio bearer with the <NUM> RAN <NUM> by using the QoS flow associated with the determined QFI (Step S80).

Moreover, the UE <NUM> identifies, by using the mapping information, the QoS flow associated with the EPS bearer identified by the EBI. Furthermore, the UE <NUM> generates the quality-of-service rule (<NUM> QoS Rule) associated with the QoS flow based on the filter (TFT) associated with the EPS bearer (in the same manner as the SMF/PGW-C <NUM> does at Step S10).

<FIG> and <FIG> are views for explaining an operation up to generation of setting content of the PDU session (QoS flow) based on setting content of the PDN connection (EPS bearer).

Specifically, <FIG> is a view for explaining an operation for identifying, by using the mapping information, the PDU session (QoS flow) associated with the PDN connection (EPS bearer).

<FIG> is a view for explaining an operation for generating, based on the filter (TFT) associated with the EPS bearer, the quality-of-service rule (<NUM> QoS Rule) associated with the identified QoS flow.

First of all, as shown in <FIG>, the UE <NUM> (also the SMF/PGW-C <NUM>, this holds true in the below explanation as well) identifies, based on the above-explained mapping information containing the association between the EPS Bearer ID and the QoS Flow ID, the QFI associated with the EBI of the set EPS bearer.

For example, as shown in <FIG>, the UE <NUM> identifies QFIx (EBI1=>QFIx) of the QoS flow (PDU session <NUM>) associated with EBI1 of EPS bearer <NUM> (PDN connection <NUM>). Similarly, the UE <NUM> performs identification of EBI2=>QFIy. Note that, in <FIG> (and <FIG>), separately from the EBI and the QFI, formal numbers of the EPS bearer and the <NUM> QoS Rule (EPS bearer <NUM>, <NUM> QoS Rule <NUM>, and the like) have been shown for the sake of convenience.

As shown in <FIG>, the setting information of the EPS bearer includes, other than the EBI, QoS Class Identifier (QCI), the TFT (filter list), and the like. Such TFT is widely used in the VoLTE and the like (e.g., QCI=<NUM> for voice and QCI=<NUM> for video).

When the UE <NUM> performs the handover from <NUM> (EPC) to <NUM> (5GC), it is necessary that each of the UE <NUM> and the 5GC (also SMF/PGW-C <NUM>) recognizes a common <NUM> QoS Rule (that is, TFT) applied to the QoS flow that the UE <NUM> uses after the handover to 5GC is over. If such a common <NUM> QoS Rule is recognized by both the UE <NUM> and the 5GC, it is possible to add or delete the <NUM> QoS Rule.

Then, the UE <NUM> generates the <NUM> QoS Rule associated with the QoS flow identified based on the mapping information. Specifically, the UE <NUM> generates content of the <NUM> QoS Rule based on content of the TFT (filter list) associated with the EPS bearer. Precisely, the UE <NUM> derives the content of the <NUM> QoS Rule based on the content of the TFT. That is, between the UE <NUM> and the 5GC (also SMF/PGW-C300 and the like), it is not necessary to exchange data and the like for synchronizing the content of the <NUM> QoS Rules.

Specifically, as shown in <FIG>, the content of the TFT and the content of the <NUM> QoS Rule are associated one-to-one. Specifically, the Filter id of the TFT and the Rule id of the <NUM> QoS Rule are associated one-to-one.

For example, the content of the TFT of EBI=<NUM> is associated with the <NUM> QoS Rule of QFI=<NUM>. Note that, it is assumed that the association EBI5=>QFI7 is identified based on the mapping information.

Moreover, the Precedence order and the Filter Content of the TFT are copied as the content of the <NUM> QoS Rule.

In the example shown in <FIG>, the EPS bearer <NUM> is a default EPS bearer (QCI=<NUM>) and it is meant for SIP (Session Initiation Protocol) traffic. The TFT (Filter id=<NUM>) of the EPS bearer <NUM> is a filter (TCP/UDP port <NUM>) for the SIP, and the traffic other than the SIP traffic is blocked (the EPS bearer cannot be used).

EPS bearer <NUM> is the EPS bearer (QCI=<NUM>) for exclusive use for voice media. The TFT (Filter id=<NUM>) of the EPS bearer <NUM> is a filter for RTP traffic (voice media). The TFT (Filter id=<NUM>) of the EPS bearer <NUM> is a filter for RTCP traffic (control for voice RTP). The content of the TFT (Filter id=<NUM>, <NUM>) of the EPS bearer <NUM> is also associated with a particular <NUM> QoS Rule, the <NUM> QoS Rule of QFI=<NUM> in the example shown in <FIG>. Because each of the TFTs (Filter id=<NUM>, <NUM>) is associated with the EPS bearer <NUM> (EBI=<NUM>), the content of those TFTs is generated as the <NUM> QoS Rule <NUM>, <NUM> associated with the same QFI (QFI=<NUM>).

In the EPS bearer <NUM>, the Precedence order of the TFT of Filter id=<NUM> is <NUM>, and the Precedence order of the TFT of Filter id=<NUM> is <NUM>. Smaller the value is, higher the priority is. The TFT of Filter id=<NUM> is, as mentioned earlier, for the RTCP traffic, and, among the TFTs shown in <FIG>, has the highest priority. Moreover, the TFT of Filter id=<NUM> is for the RTP traffic (voice media), and to give weight to real-timeness, the priority (<NUM>) thereof is set to a little higher than the Precedence order (<NUM>) of the TFT for the SIP.

The Rule id is generated automatically based on a rule that uses the value of the EBI. Specifically, by expressing a value (<NUM> bits) of the EBI with the upper four bits of the Rule id and expressing a value of the Filter id with the lower four bits of the Rule id, the Rule id is configured so as to be able to be identified uniquely between PDU sessions.

For example, as shown in <FIG>, because the Rule id (<NUM> bits integer number) of the <NUM> QoS Rule <NUM> is associated with EBI=<NUM> and Filter id=<NUM>, the Rule id of the <NUM> QoS Rule <NUM> becomes 0x51.

A specific sequence of the inter-system handover from <NUM> to <NUM> performed by the UE <NUM> is explained below.

In this operation example, a sequence of the inter-system handover when the state of the UE <NUM> in the 5GC is the connected mode (connected mode) is explained.

<FIG> shows an example of a sequence in a handover preparation phase. <FIG> shows an example of a sequence in a handover execution phase.

Note that, the examples of the sequences shown in <FIG> and <FIG> are shown in 3GPP TS <NUM> Section <NUM> (System interworking procedures with EPS), and the like. Particularly, the examples of the sequences shown in <FIG> and <FIG> are shown in the document related to <NPL>). The content that is different from the above document is mainly explained below.

As shown in <FIG>, in the handover preparation phase, the SMF/PGW-C <NUM> generates the ID of the PDU session and assigns a predetermined QoS flow (Step <NUM> of <FIG>). When doing so, the SMF/PGW-C <NUM> uses the mapping information generated beforehand.

The SMF/PGW-C <NUM> identifies, by using the mapping information, the QoS flow associated with the EPS bearer identified based on the EBI. Furthermore, the SMF/PGW-C <NUM> generates, based on the filter (TFT) associated with the EPS bearer, the quality-of-service rule (<NUM> QoS Rule) associated with the QoS flow.

As mentioned earlier, substantially, the ID of the PDU session is associated with the default EBI of the PDN connection. Moreover, the QFI is associated with one of the EBIs.

As shown in <FIG>, in the handover execution phase, the UE <NUM> performs association between the EBI and the QFI by using the mapping information that is the same as the mapping information used by the SMF/PGW-C <NUM> (Step <NUM> shown in <FIG>).

Moreover, the UE <NUM> identifies the QoS flow associated with the EPS bearer identified by the EBI by using the mapping information. Furthermore, the UE <NUM> generates, based on the filter (TFT) associated with the EPS bearer, the quality-of-service rule (<NUM> QoS Rule) associated with the QoS flow.

In this manner, in the present operation example, because the mapping information held beforehand is used, transmission and reception of the mapping information is not performed in the handover preparation phase (specifically, at Step <NUM>) and in the handover execution phase (specifically, at Steps <NUM> and <NUM>).

Moreover, as mentioned earlier, the mapping information held by the UE <NUM> and the SMF/PGW-C <NUM> can be updated, so that an CAM (Operation, Administration, Management) system of the network (EPC, 5GC) side can supply the updated mapping information to a node of the UE <NUM>, the SMF/PGW-C <NUM>, and the like.

Setting of the QoS rule and the traffic flow template (TFT), when the UE <NUM> performs the handover from <NUM> to <NUM> and thereafter performs the handover to <NUM> again, is explained below.

<FIG> is a view for explaining the setting of the QoS rule and the TFT when the UE <NUM> performs <NUM>-<NUM>-<NUM> handover.

As shown in <FIG>, when the UE <NUM> performs transition (handover) from <NUM> to <NUM>, as mentioned earlier, the UE <NUM> and the 5GC (SMF/PGW-C <NUM>) autonomously generate the <NUM> QoS Rule, that is, derive the <NUM> QoS Rule based on the TFT of the EPS bearer.

Then, during a period in which the UE <NUM> is communicating (including waiting) via the <NUM>, when a requirement arises in the 5GC to change the <NUM> QoS Rule, even the content of the TFT of the EPS bearer associated with the <NUM> QoS Rule that is the target to be changed is changed, and the UE <NUM> is notified of the changed content.

Moreover, when the 5GC sets a new QoS flow (QFI), the 5GC notifies the UE <NUM> of the content (entire content) of the TFT of the EPS bearer associated with the <NUM> QoS Rule of the new QoS flow. Note that, such notification can be implemented by PDU Session Modification procedure (e.g., "<NPL>).

Moreover, for the time being, assuming that addition or correction of the service occurs when the UE <NUM> transitions to the <NUM>, requiring addition of the <NUM> QoS Rule or changing the content of the QoS flow, because the <NUM> QoS Rule is a superset of the TFT, it is necessary to update the entire content of the associated TFT. Therefore, in such a case, it is necessary to start and perform the normal PDU Session Modification procedure on the NW side.

When the UE <NUM> performs the transition (handover) back to <NUM> from <NUM>, because the UE <NUM> is already holding the TFT of the EPS bearer associated with the <NUM> QoS Rule being used, the UE <NUM> uses this TFT and continues communication via the EPS bearer.

According to the present embodiment, the following effects and advantages can be obtained. Specifically, the UE <NUM> (and SMF/PGW-C <NUM>) can generate, precisely, derive, based on the EBI and the filter (TFT) of the EPS bearer, the <NUM> QoS Rule associated with the QoS flow identified based on the mapping information.

Therefore, like in the VoLTE, even when the EPS bearer is associated with a particular TFT, the content of the TFT can be autonomously reflected in the <NUM> QoS Rule associated with the QoS flow of the handover destination. That is, according to the radio communication system <NUM>, even when the EPS bearer is associated with a particular TFT, a flexible inter-system handover (from <NUM> to <NUM> and from <NUM> to <NUM>) of the UE <NUM> can be implemented while maintaining a desired quality of the service.

Moreover, because there is no need to perform a communication between the UE <NUM> and the 5GC for generating the <NUM> QoS Rule, reduction in the processing load, saving of the radio resource, and quicker handover can be achieved.

In the present embodiment, the <NUM> QoS Rule can be generated at the time of performing the handover of the UE <NUM> from <NUM> to <NUM>. Therefore, a new <NUM> QoS Rule can be generated depending on the need of the <NUM> QoS Rule.

In the present embodiment, the Rule id having a regularity can be generated automatically based on the EBI and the Filter id. Therefore, even when the UE <NUM> and the 5GC (SMF/PGW-C <NUM>) independently generate respective <NUM> QoS Rules, the same Rule id can be allocated, and the same <NUM> QoS Rule can be surely recognized in the UE <NUM> and the 5GC.

Although the contents of the present disclosure have been explained above by using the embodiments, it is obvious for a person skilled in the art that the present invention is not limited to those embodiments and that various modifications and improvements thereof are possible, as long as they are covered by the terms of the appended claims.

For example, in the above embodiments, the SMF/PGW-C <NUM> generated and held the mapping information and the quality-of-service rule (<NUM> QoS Rule). Alternatively, the mapping information and the quality-of-service rule can be generated or held or both by other nodes (e.g., AMF <NUM>) that constitute the 5GC or other nodes (e.g., MME <NUM>) that constitute the EPC.

Moreover, the use of the above method of generating the <NUM> QoS Rule is not limited to when performing the handover of the UE <NUM>. For example, the above method of generating the <NUM> QoS Rule can be used, when the content of the TFT is updated and the like, to notify this fact to the related node (UE <NUM>, MME <NUM>, SGW150, SMF/PGW-C <NUM>, and the like) by Protocol Configuration Options (PCO) prescribed in 3GPP <NUM>.

Moreover, the block diagrams used for explaining the embodiments (<FIG>) show functional blocks. Those functional blocks (structural components) can be realized by a desired combination of hardware and / or software. Means for realizing each functional block is not particularly limited. That is, each functional block may be realized by one device combined physically and / or logically. Alternatively, two or more devices separated physically and / or logically may be directly and / or indirectly connected (for example, wired and / or wireless) to each other, and each functional block may be realized by these plural devices.

Furthermore, the UE <NUM> (devices) explained above can function as a computer that performs the processing of the present invention. <FIG> is a diagram showing an example of a hardware configuration of the devices. As shown in <FIG>, each of the devices can be configured as a computer device including a processor <NUM>, a memory <NUM>, a storage <NUM>, a communication device <NUM>, an input device <NUM>, an output device <NUM>, and a bus <NUM>.

The functional blocks of the devices (see <FIG>) can be realized by any of hardware elements of the computer device or a desired combination of the hardware elements.

The processor <NUM>, for example, operates an operating system to control the entire computer. The processor <NUM> can be configured with a central processing unit (CPU) including an interface with a peripheral device, a control device, a computing device, a register, and the like.

The memory <NUM> is a computer readable recording medium and is configured, for example, with at least one of ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), and the like. The memory <NUM> can be called register, cache, main memory (main memory), and the like. The memory <NUM> can store therein a computer program (computer program codes), software modules, and the like that can execute the method according to the above embodiments.

The storage <NUM> is a computer readable recording medium. Examples of the storage <NUM> include an optical disk such as CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (for example, a compact disk, a digital versatile disk, a Blu-ray (Registered Trademark) disk), a smart card, a flash memory (for example, a card, a stick, a key drive), a floppy (Registered Trademark) disk, a magnetic strip, and the like. The storage <NUM> can be called an auxiliary storage device. The recording medium can be, for example, a database including the memory <NUM> and / or the storage <NUM>, a server, or other appropriate medium.

The communication device <NUM> is hardware (transmission / reception device) capable of performing communication between computers via a wired and / or wireless network. The communication device <NUM> is also called, for example, a network device, a network controller, a network card, a communication module, and the like.

The input device <NUM> is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, and the like) that accepts input from the outside. The output device <NUM> is an output device (for example, a display, a speaker, an LED lamp, and the like) that outputs data to the outside. Note that, the input device <NUM> and the output device <NUM> may be integrated (for example, a touch screen).

In addition, the respective devices, such as the processor <NUM> and the memory <NUM>, are connected to each other with the bus <NUM> for communicating information there among. The bus <NUM> can be constituted by a single bus or can be constituted by separate buses between the devices.

In addition, the manner of notification of information is not limited to the one explained in the embodiments, and the notification may be performed in other manner. For example, the notification of information can be performed by physical layer signaling (for example, DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (for example, RRC signaling, MAC (Medium Access Control) signaling, notification information (MIB (Master Information Block), SIB (System Information Block)), other signals, or a combination thereof. In addition, the RRC signaling can be called an RRC message, and the RRC signaling can be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, and the like.

Furthermore, the input / output information can be stored in a specific location (for example, a memory) or can be managed in a management table. The information to be input / output can be overwritten, updated, or added. The information can be deleted after outputting. The inputted information can be transmitted to another device.

The order of the sequences, flowcharts, and the like in the embodiments can be rearranged unless there is a contradiction.

Moreover, in the embodiments explained above, the specific operations performed by the SMF/PGW-C <NUM> can be performed by another network node (device). Moreover, functions of the SMF/PGW-C <NUM> can be provided by combining a plurality of other network nodes.

Moreover, the terms used in this specification and / or the terms necessary for understanding the present specification can be replaced with terms having the same or similar meanings. For example, a channel and / or a symbol can be replaced with a signal (signal) if that is stated. Also, the signal can be replaced with a message. Moreover, the terms "system" and "network" can be used interchangeably.

Furthermore, the used parameter and the like can be represented by an absolute value, can be expressed as a relative value from a predetermined value, or can be represented by corresponding other information. For example, the radio resource can be indicated by an index.

The radio base stations <NUM> and <NUM> (base station) can accommodate one or more (for example, three) cells (also called sectors). In a configuration in which the base station accommodates a plurality of cells, the entire coverage area of the base station can be divided into a plurality of smaller areas. In each such a smaller area, communication service can be provided by a base station subsystem (for example, a small base station for indoor use RRH: Remote Radio Head).

The term "cell" or "sector" refers to a part or all of the coverage area of a base station and / or a base station subsystem that performs communication service in this coverage. In addition, the terms "base station" "eNB", "cell", and "sector" can be used interchangeably in the present specification. The base station can also be referred to as a fixed station, Node B, eNode B (eNB), gNode B (gNB), an access point, a femtocell, a small cell, and the like.

The UE <NUM> is called by the persons skilled in the art as a subscriber station, a mobile unit, a subscriber unit, a radio unit, a remote unit, a mobile device, a radio device, a radio communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a radio terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or with some other suitable term.

As used herein, the phrase "based on" does not mean "based only on" unless explicitly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on".

Furthermore, the terms "including", "comprising", and variants thereof are intended to be inclusive in a manner similar to "having". Furthermore, the term "or" used in the specification or claims is intended not to be an exclusive disjunction.

Any reference to an element using a designation such as "first", "second", and the like used in the present specification generally does not limit the amount or order of those elements. Such designations can be used in the present specification as a convenient way to distinguish between two or more elements. Thus, the reference to the first and second elements does not imply that only two elements can be adopted, or that the first element must precede the second element in some or the other manner.

Throughout the present specification, for example, during translation, if articles such as a, an, and the in English are added, these articles shall include plurality, unless it is clearly indicated that it is not so according to the context.

As described above, the details of the present invention have been disclosed by using the embodiments of the present invention. However, the description and drawings which constitute part of this disclosure should not be interpreted so as to limit the present invention, which is solely defined by the appended claims. From this disclosure, various alternative embodiments, examples, and operation techniques will be apparent to a person skilled in the art.

Claim 1:
A user device (<NUM>) that performs handover between a first radio communication network according to <NUM> and a second radio communication network according to <NUM>, comprising:
an association information holding unit (<NUM>) configured to hold association information indicative of an association between a type of a bearer set in the first radio communication network and a type of a flow that is set in the second radio communication network and that depends on a quality of service;
a filter holding unit (<NUM>) configured to hold a filter of a traffic flow associated with the bearer set for the user device in the first radio communication network;
a rule deriving unit (<NUM>) configured to derive, based on a bearer identifier for recognizing the type of the bearer and the filter held by the filter holding unit, a quality-of-service rule associated with the flow; and
a handover executing unit (<NUM>) configured to perform the handover from the first radio communication network to the second radio communication network; wherein the rule deriving unit (<NUM>) is configured to derive the quality-of-service rule when the handover is performed by the handover executing unit (<NUM>).