KR20210017992A - Method and apparatus for improving voice service quality in wireless communication system - Google Patents

Abstract

The present disclosure relates to a communication method and system for converging a 5G communication system for supporting higher data transmission rates beyond a 4G system with a technology for IoT. The present disclosure may be applied to intelligent services (such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services) based on the 5G communication technology and the IoT-related technology.

Description

Method and device to improve voice service quality in wireless communication system {METHOD AND APPARATUS FOR IMPROVING VOICE SERVICE QUALITY IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to a method of improving service quality in a mobile communication system.

Efforts are being made to develop an improved 5G communication system or a pre-5G communication system in order to meet the increasing demand for wireless data traffic after the commercialization of 4G communication systems. For this reason, a 5G communication system or a pre-5G communication system is called a Beyond 4G Network communication system or an LTE system and a Post LTE system. In order to achieve a high data rate, the 5G communication system is being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Giga (60 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, in 5G communication systems, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, in order to improve the network of the system, in 5G communication system, advanced small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation And other technologies are being developed. In addition, in the 5G system, advanced coding modulation (ACM) methods such as Hybrid FSK and QAM Modulation (FQAM) and SWSC (Sliding Window Superposition Coding), advanced access technologies such as Filter Bank Multi Carrier (FBMC), NOMA (non orthogonal multiple access), and sparse code multiple access (SCMA) have been developed.

On the other hand, the Internet is evolving from a human-centered network in which humans generate and consume information, to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, a sensor network for connection between objects, machine to machine , M2M), and MTC (Machine Type Communication) technologies are being studied. In the IoT environment, intelligent IT (Internet Technology) services that create new value in human life by collecting and analyzing data generated from connected objects can be provided. IoT is the field of smart home, smart building, smart city, smart car or connected car, smart grid, healthcare, smart home appliance, advanced medical service, etc. through the convergence and combination of existing IT (information technology) technology and various industries. Can be applied to.

Accordingly, various attempts have been made to apply a 5G communication system to an IoT network. For example, technologies such as sensor network, machine to machine (M2M), and MTC (Machine Type Communication) are implemented by techniques such as beamforming, MIMO, and array antenna, which are 5G communication technologies. will be. As the big data processing technology described above, a cloud radio access network (cloud RAN) is applied as an example of the convergence of 5G technology and IoT technology.

Meanwhile, due to the development of various IT technologies, network equipment has evolved into a virtualized NF (Network Function) by applying a virtualization technology. It is implemented in W form and can be installed/operated in various types of Cloud or DC (Data Center). In particular, NF can be freely expanded/reduced or installed/terminated according to service requirements, system capacity, and network load.

The present invention for solving the above problem is a control signal processing method in a wireless communication system, the method comprising: receiving a first control signal transmitted from a base station; Processing the received first control signal; And transmitting a second control signal generated based on the processing to the base station.

The present invention proposes a method and apparatus for improving voice service quality in a wireless communication system through various embodiments of the present invention.

1 is a diagram illustrating a structure of an SBA-based 5G system according to an embodiment of the present invention.
2 is a diagram illustrating a network structure according to an embodiment of the present invention.
3 is a diagram illustrating an operation of a terminal and a network according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating an operation of a terminal and a network capable of more effective operation when 5GC is linked with various types of NG-RANs (NR and E-UTRA) according to an embodiment of the present invention.
5 is a diagram illustrating an operation for a terminal to select a network that provides an optimal voice service according to an embodiment of the present invention.
6A shows the operation of a terminal, a base station, and a core (5GC and EPC) according to an embodiment of the present invention.
6B shows the operation of a terminal, a base station, and a core (5GC and EPC) according to another embodiment of the present invention.
7 is a diagram showing the configuration of a network entity (Network Entity) according to the present invention.
8 is a diagram illustrating a flow of an operation of continuously providing a service by processing a session when moving between a 5G network (5GS) and a 4G network (EPS) according to another embodiment of the present invention.
9 is a diagram illustrating an NF (AMF) operation of a network according to another disclosure of the present invention.
10 is a diagram illustrating an operation of a terminal supporting ATSSS in another disclosure of the present invention.

Hereinafter, the operating principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary depending on the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout this specification.

A term for identifying an access node used in the following description, a term for a network entity or NF (network function), a term for messages, a term for an interface between network objects, various Terms and the like referring to identification information are exemplified for convenience of description. Therefore, the present invention is not limited to the terms described below, and other terms referring to objects having an equivalent technical meaning may be used.

For convenience of description below, the present invention uses terms and names defined in 3GPP 3rd Generation Partnership Project Long Term Evolution (LTE) and 5G standards. However, the present invention is not limited by the terms and names, and can be applied equally to systems conforming to other standards.

Meanwhile, in describing the embodiments of the present invention, a method for improving the quality of voice service in a state in which 5G and LTE (4G) systems coexist, but the main subject of the present invention can be applied to any type of wireless communication system. In addition, it can be applied not only to voice services but also to other types of services (video calls, gaming, chatting, etc.).

In order to support various services of 5G, a new system structure and protocol were required, and 3GPP decided to introduce a new technology called service-based architecture (SBA). The main characteristic of the service-based structure is to divide the functionalities of NFs defined in the 3GPP standard into service units, taking into account the introduction of the virtualization technology, cloud environment, and expansion of web-based services described above, and HTTP in implementing these services. /2 protocol.

1 is a diagram illustrating a structure of an SBA-based 5G system according to an embodiment of the present invention.

Referring to FIG. 1, an access and mobility management function (AMF) is a network function (NF) for managing wireless network access and mobility for a terminal (UE). A session management function (SMF) is an NF that manages a session for a terminal, and the session information includes QoS information, billing information, and packet processing information. A user plane function (UPF) is an NF that processes user plane traffic and can be controlled by SMF. Although not shown in FIG. 1, the 5G system may include UDSF, and the UDSF (unstructured data storage network function) is an NF that stores unstructured data, and any type of data is stored at the request of the NF. ) Or retrieve.

2 is a diagram illustrating a network structure according to an embodiment of the present invention.

For simplicity in describing the drawings and embodiments of the present invention, it is assumed that the SGW and PGW are integrated, and the PCRF and PCF are integrated, but the gist and utilization of the embodiments of the present invention can be applied even when they are separated. have. In addition, in the figure, E-UTRA is a case in which the UE uses an EPC NAS (Non-access Stratum) in the E-UTRA network (ie, when the E-UTRA is connected to the MME) and when the 5GC NAS is used (ie, E- When UTRA is connected to the AMF) is indicated without distinction, but in practice each implementation and use can be implemented in a separate form.

Although not shown in the logical network structure, the cells of 5G-RAN and 4G (E-UTRA) may overlap each other depending on the construction type of the physical wireless network. If 5G cell coverage is insufficient at the initial stage of commercialization of 5G, it may be configured to support a voice/video call service in a specific RAT (4G in the case of the present invention). In addition, if several types of Core networks (5GC, EPC) coexist according to the operator setting, the voice/video call service may be set to support only a specific Core network. For example, depending on the time of commercialization, the voice/video service may be set to be supported only by EPC rather than 5GC.

If the voice/video call service occurs while the UE is registered in the network, and the type of RAT or Core network to which the UE is currently connected needs to be changed, the RAT capable of supporting the voice/video call service or It must be transferred to the core network. Such a transition may be caused by explicitly transmitting a command or request message to the terminal in the network, or the terminal may actively perform it in consideration of the current state.

3 is a diagram illustrating the operation of a terminal and a network according to an embodiment of the present invention.

In step 1, the terminal selects a system to be accessed, requests connection, and then transmits a registration message for registration with the system. This message may include the UE's Capability and Usage Setting, and the Usage Setting may indicate whether the type of the UE requires a voice call (Voice Centric).

In step 2, the base station (NG-RAN, that is, the E-UTRAN interlocked with 5G-RAN or 5GC) may include the NAS message received from the terminal in the NGAP message and deliver it to the AMF. In this embodiment, the NAS message is a registration request, and the NGAP message may include the type of RAT (whether NR or E-UTRA, etc.) to which the terminal is currently connected.

In step 3, the AMF processes the NAS request of the terminal, and may receive subscription data from UDM during the registration process. The subscription information may include whether or not to allow the voice service to the terminal (whether IMS service is allowed or IMS DNN is allowed).

In step 4, the AMF may determine whether to support the IMS Voice service for the terminal. The AMF makes a decision in consideration of the information of the terminal received in step 1 (Capability, Usage Setting, etc.), the RAT type currently accessed by the terminal received from the NG-RAN in step 2, and the subscription information received from the UDM in step 3. I can. Particularly, if the IMS voice service is supported only by a specific RAT even though the same 5GC according to the situation of the operator's network, it can be determined by comparing it with the RAT Type received from the NG-RAN. Also, the AMF may additionally perform a UE Capability Match process and make a decision by reflecting the result.

In addition, the AMF determines the RFSP Index to be applied to the UE, and similarly, the Usage Setting transmitted by the UE and the IMS Voice over PS Session Support Indication to be applied to the UE may be considered. More specifically, if the usage setting of the terminal is Voice Centric and it is not possible to provide IMS Voice service in the current network, the AMF can use the RFSP Index to induce the terminal to stay in the RAT capable of supporting voice service as much as possible. Conversely, if the usage setting of the terminal is not Voice Centric, the RFSP Index can be used to induce the terminal to stay in a wireless network (such as NR) capable of high-speed data transmission as much as possible.

In step 5, the AMF may transmit a registration acceptance message to the terminal. If it is determined in step 4 that the IMS Voice service support is possible for the terminal, the AMF may include the IMS Voice over PS Session Supported Indication in the Registration Accept message and transmit. This message may be delivered to the terminal in step 6 through the NG-RAN.

In step 7, the terminal may perform an operation for selecting a voice domain according to whether the IMS Voice over PS session supported indication is included in the registration acceptance message received from the AMF.

If the indication is included and the currently connected network (RAN and Core) does not need to be changed, the terminal performs an operation to receive a voice service through the IMS network in step 8, which includes the PDU Session Establishment and IMS Registration process through the IMS DNN. May be included.

4 is a diagram illustrating an operation of a terminal and a network capable of more effective operation when 5GC is interlocked with various types of NG-RANs (NR and E-UTRA) according to an embodiment of the present invention.

In step 1, the terminal may select a system to be accessed, request a connection, and then transmit a registration message for registration with the system. This message may include the UE's Capability and Usage Setting, and the Usage Setting may indicate whether the type of the UE requires a voice call (Voice Centric).

In step 2, the base station (NG-RAN, that is, the E-UTRAN interlocked with 5G-RAN or 5GC) may include the NAS message received from the terminal in the NGAP message and deliver it to the AMF. In this embodiment, the NAS message is a registration request, and the NGAP message may include the type of RAT (whether NR or E-UTRA, etc.) to which the terminal is currently connected.

In step 3, the AMF processes the NAS request of the terminal, and may receive subscription data from UDM during the registration process. The subscription information may include whether or not to allow the voice service to the terminal (whether IMS service is allowed or IMS DNN is allowed).

In step 4, the AMF may determine whether to support the IMS Voice service for the terminal. The AMF may make a decision in consideration of the terminal information (Capability, Usage Setting, etc.) received in step 1 and subscription information received from the UDM in step 3. In particular, if the IMS voice service is supported only by a specific RAT even though the same 5GC according to the situation of the operator network, the AMF may separately determine whether or not the IMS voice service is available for each RAT. Also, the AMF may additionally perform a UE Capability Match process and make a decision by reflecting the result.

In addition, the AMF determines the RFSP Index to be applied to the UE, and similarly, the Usage Setting transmitted by the UE and the IMS Voice over PS Session Support Indication to be applied to the UE may be considered. More specifically, if the usage setting of the terminal is Voice Centric and it is not possible to provide IMS Voice service in the current network, the AMF can use the RFSP Index to induce the terminal to stay in the RAT capable of supporting voice service as much as possible. Conversely, if the usage setting of the terminal is not Voice Centric, the RFSP Index can be used to induce the terminal to stay in a wireless network (such as NR) capable of high-speed data transmission as much as possible.

In step 5, the AMF may transmit a registration acceptance message to the terminal. After determining whether to support the IMS Voice service for each RAT type in step 4, the AMF may set and transmit the IMS Voice over PS Session Supported per RAT type in the Registration Accept message. For example, if 5GC is set to support voice service in the operator's network, but the NR linked to 5GC does not support voice service, and only supports voice service through E-UTRA linked to 5GC, IMS voice over PS session supported is set as supported for E-UTRA and not supported for NR, and this message may be delivered to the terminal in step 6 through NG-RAN.

In step 7, the UE may perform an operation for selecting a Voice Domain according to whether the IMS Voice over PS session supported indication is included in the Registration Accept message received from the AMF and the currently accessed RAT Type.

If the indication is included and the currently accessed network (RAN and Core) does not need to be changed, that is, if the IMS Voice over PS Session Supported Indication is received for the RAT type that the UE is currently accessing, the UE goes to the IMS network in step 8. It performs an operation to receive a voice service, and this may include a PDU Session Establishment and IMS Registration process through an IMS DNN. In addition, the terminal stores the IMS Voice over PS Session Supported Indication set for each RAT, and should be used for Voice Domain Selection according to the indication for the corresponding RAT when the RAT accessed by the terminal is changed in the future.

5 shows an operation for a terminal to select a network that provides an optimal voice service according to an embodiment of the present invention.

In step 1, the terminal performs the registration process, and can transmit a registration request message including usage setting set in the terminal to the network. Usage Setting may include information indicating whether the terminal should receive a voice service.

In step 2, the terminal receives a registration response message from the network, and this message may include IMS Voice over PS Session Supported Indication per RAT Type.

In step 3, the terminal determines whether the usage setting is Voice Centric, and if so, proceeds to step 4, otherwise the entire process is terminated.

In step 4, the terminal determines whether IMS Voice is supported in the currently accessed RAT type based on the information received in step 2. If so, the process proceeds to step 5 and the UE performs an operation to receive an IMS voice service, that is, establishes a PDU session through IMS DNN/APN and performs IMS Registration. If not, go to step 6.

In step 6, the terminal determines whether IMS Voice is supported in another RAT type based on the information received in step 2. If so, the process proceeds to step 7 and the UE performs an operation to attempt to access the RAT supporting IMS Voice. If not, the terminal proceeds to step 8 and performs another operation (combined attach or TA/LA update in 4G network or transition to 2G/3G network) for receiving voice service.

An embodiment of the present invention proposes a method for effectively providing a voice/video call service in a network structure in which E-UTRA is linked to 5GC in an operator network. At this time, both 5GC and EPC are established in the operator's network, and in this case, the E-UTRAN has a network structure linked to both 5GC and EPC (see FIG. 2). At this time, 5G-RAN using NR may exist in the operator network.

6A shows the operation of a terminal, a base station, and a core (5GC and EPC) according to an embodiment of the present invention.

In step 1, the terminal performs a process for registration in 5GC with the AMF. In this case, the terminal may include an indication in the registration request message indicating that it supports the function of the present embodiment capable of effectively processing a fallback for a voice (or video) call service. Depending on the network structure, the AMF may deliver the IMS voice over PS session supported indication and the EPS Fallback support indication to the Registration Accept message sent to the UE. Although omitted in the drawing, the terminal may generate a PDU session for the IMS DNN in order to use a voice (or video) call service when receiving this, and perform a process of registering with the IMS. In addition, although omitted in the drawing, the AMF may include an indication that the terminal supports an additional function capable of effectively handling fallback in the NG-AP message sent to the NG-RAN. Alternatively, the terminal may transmit an indication informing that it supports an additional function capable of effectively handling fallback in an RRC message sent to the NG-RAN.

When a voice (or video) call occurs in step 2 (both transmission/reception is possible), the process for IMS Voice over PS session is processed, and during this process, IMS Media QoS Flow (can be classified as a specific 5QI: 5QI = 1, etc.) is triggered, and the AMF notifies the NG-RAN in step 3.

In step 4, the NG-RAN (E-UTRA linked to 5GC in this embodiment) determines that a fallback should be performed during the IMS Media QoS Flow processing process, and a fallback process for providing a voice (or video) service of the terminal is performed. Start. At this time, the NG-RAN determines that the fallback process can be effectively performed based on the information received from the AMF or the terminal. At this time, in the embodiment of the present invention, the effective execution of the fallback process is different from the existing fallback techniques, using the same RAT type (E-UTRA) that the terminal accesses before and after the fallback process, It means improving the quality of service by shortening the time from when the call is available. In this step, the NG-RAN/E-UTRAN performs an operation to optimize the fallback process. Since the RAT type of NG-RAN and E-UTRAN is the same as E-UTRA, NG-RAN and E-UTRAN may be implemented in the form of one device, and the protocol and information used for communication with the terminal and AMF are different. Therefore, NG-RAN and E-UTRAN may be constructed in a separate form. In the former case, the NG-RAN directly generates information to be used by the terminal falling back to the E-UTRAN and transmits it to the terminal. When the change of the cell to which the terminal is connected is unnecessary, a separate radio state measurement process is shortened and It is possible to induce to change only the core type, or to select a cell of the E-UTRAN to be accessed by the terminal in consideration of the current state and radio state of the terminal and transmit it to the terminal. In the latter case, the NG-RAN receives information from the E_UTRAN and delivers it to the terminal. In both cases, the information transmitted to the terminal includes information indicating that the cause of the transition of the terminal is Fallback, information of the cell that the terminal will access from the E-UTRAN (may be multiple cells), and if the cell needs to be changed, the terminal A parameter to be used for initial access (some essential information among SIB/MIB, for example, MIB and SIB 1/2) may be included. In addition, the NG-RAN may reserve uplink resources in advance (that is, by generating an Uplink Grant) so that the UE can transmit a message on the uplink immediately upon initial access to the E-UTRAN and transmit it to the UE. If the NG-RAN and E-UTRAN are separated, the NG-RAN transmits a resource allocation request to the E-UTRAN, receives an Uplink Grant, and delivers it to the terminal.

The information generated in step 5 is transmitted to the terminal, and the method used at this time may be one of RRC Connection Release or NW-Triggered Handover. If the RRC Connection Release method is used, the UE releases the RRC connection with the NG-RAN in step 6, and uses the information included in the Connection Release command message (E-UTRAN access information generated in step 4) to E- A cell of the UTRAN is selected and initial access is performed. If the received information includes an Uplink Grant, it can be used to immediately transmit an RRC connection creation message without a separate resource allocation request process. If the handover scheme is used, the terminal performs a process for handover from the NG-RAN to the E-UTRAN in step 6.

In step 7, the terminal performs an EPS and inter-system tracking area update process. During this process, the context of the terminal is transferred from 5GC to the EPC, and the terminal is then registered with the EPC to receive the service. Thereafter, the terminal and the network perform a process for receiving the remaining voice service.

6B shows the operation of a terminal, a base station, and a core (5GC and EPC) according to another embodiment of the present invention.

Another embodiment of the present invention proposes another method of improving quality through media flow processing when a fallback for a voice (or video) call service occurs. In this embodiment, the RAT Type of NG-RAN linked to 5GC may be NR or E-UTRA. The main feature of this embodiment is to prevent a situation in which a failure occurs in the process of adding an EPS bearer for IMS Media transmission in the EPS (E-UTRAN + EPC) after a fallback occurs, or the time for signaling is prolonged, thereby improving service quality. That's the way.

In step 1, the terminal performs a process for registration in 5GC with the AMF. In this case, the terminal may include an indication in the registration request message indicating that it supports the function of this embodiment that can effectively process a media bearer for a voice (or video) call service. Depending on the network structure, the AMF may deliver the IMS voice over PS session supported indication and the EPS Fallback support indication to the Registration Accept message sent to the UE. Although omitted in the drawing, the terminal may generate a PDU session for the IMS DNN in order to use a voice (or video) call service when receiving this, and perform a process of registering with the IMS. During the PDU Session creation process for the IMS DNN, the UE and the SMF (+PGW-C) can inform each other that they support a function that can effectively process the IMS Voice Media when a fallback occurs. This information may directly include the indicator in a session management (SM) NAS message exchanged between the terminal and the SMF (+PGW-C) or may be exchanged using a Protocol Configuration Option (PCO).

When a voice (or video) call occurs in step 2 (both transmission/reception is possible), the process for IMS Voice over PS session is processed, and during this process, IMS Media QoS Flow (can be classified as a specific 5QI: 5QI = 1, etc.) is triggered, and the AMF notifies the NG-RAN in step 3.

In step 4, the NG-RAN (E-UTRA linked to 5GC in this embodiment) determines that a fallback should be performed during the IMS Media QoS Flow processing process, and a fallback process for providing a voice (or video) service of the terminal is performed. Start.

In step 5, the UE performs the EPS Fallback process using the information of the message received from the NG-RAN.

In step 6, the terminal performs an Inter-system Tracking Area Update process. During this process, the default bearer of the IMS PDU Session (PDN Connection) is created.

In step 7, the EPC (GW) knows that the EPS Fallback process is in progress, cancels the IMS Media Flow creation that has not been completed after attempting in Step 2, and performs an operation to transmit and receive IMS Media using the Default Bearer of the IMS Session. do. This operation may be applied only when a function of effectively providing media processing when an EPS fallback occurs between the terminal and the network in step 1 is exchanged with each other, or may be implicitly applied to all terminals. In addition, this operation can be applied only when media flow generation fails (eg, resource allocation failure in the base station) or does not succeed for a predetermined time. This operation may include adding a packet filter for transmitting/receiving IMS media flow between the terminal and the network to the default bearer, or setting the packet filter of the default bearer to match-all, and during this process, the GW Can explicitly inform the PCF (PCRF) that the default bearer is used to provide Media Flow.

Afterwards, in step 8, the IMS media flow is transmitted and received between the terminal and the network through the default bearer of the IMS PDN Connection, thereby enabling a voice call. If an additional EPS bearer for transmitting the IMS media flow is created after this, the terminal and the network allow the IMS media flow to be transmitted through the newly created dedicated bearer, and specifically bearer mapping for processing to the IMS media flow. The priority is set so that the newly created dedicated bearer is higher than the default bearer, and for this purpose, a process of modifying the packet filter for Default/Dedicated Bearers of the IMS PDN Connection may be performed.

7 is a diagram showing the configuration of a network entity according to the present invention. Referring to FIG. 7, the network entity may include a transceiver 710, a control unit 720, and a storage unit 730. The network entity of the present invention is a concept including a network function according to the system implementation.

A network entity according to an embodiment of the present invention may include a transceiver 710 and a controller 720 for controlling overall operations of the network entity. In addition, the transmission/reception unit 710 may include a transmission unit 711 and a reception unit 712.

The transceiver 710 may transmit and receive signals to and from other network entities. The transceiver 710 may receive system information from, for example, a base station, and may receive a synchronization signal or a reference signal.

The controller 720 may control the network entity to perform any one of the above-described embodiments. Meanwhile, the control unit 720 and the transmission/reception unit 710 do not necessarily have to be implemented as separate modules, but can be implemented as a single component in the form of a single chip. In addition, the control unit 720 and the transmission/reception unit 710 may be electrically connected. And, for example, the controller 720 may be a circuit, an application-specific circuit, or at least one processor. Further, the operations of the network entity can be realized by providing a memory device storing the corresponding program code in an arbitrary configuration unit in the network entity.

The network entity is any of the base station (RAN), AMF, SMF, UPF, NF, NEF, NRF, CF, NSSF, UDM, AF, AUSF, SCP, UDSF, context storage, OAM, EMS, configuration server, ID management server It can be one.

The storage unit 730 may store at least one of information transmitted and received through the transmission/reception unit 710 and information generated through the control unit 720. For example, the storage unit 730 may store scheduling information related to RMSI transmission, PDCCH time axis position and period information related to RMSI, and the like.

8 is a diagram illustrating a flow of an operation of continuously providing a service by processing a session when moving between a 5G network (5GS) and a 4G network (EPS) according to another embodiment of the present invention. Specifically, another embodiment of the present invention relates to a method of continuously providing a service by processing a session when a terminal moves between a 5G network (5GS) and a 4G network (EPS).

If the terminal moves or transitions to the 4G network while receiving a service by creating a multiple access (MA) PDU session through the 3GPP wireless network and the N3GPP (Non-3GPP) wireless network in the 5G network, processing and transmission path for the session You may need to reset it. This is a necessary function when the 4G network cannot support the MA PDU session through the N3GPP wireless network. In particular, this embodiment targets a case where there is no N26 Interface for supporting interworking services between 5GS and EPS, and in this case, the AMF of 5GS and the MME of EPS cannot directly exchange the terminal context. In the following detailed operation, PGW, PGW-C, and SMF may all refer to the same object. In this embodiment, the MA PDU session may have the same meaning as an access traffic steering, switch and splitting (ATSSS) session.

Step 1. The terminal is registered with 5GS, and can receive a service by creating a MA PDU session through both 3GPP and N3GPP wireless networks.

Step 2. The terminal may decide to transition to the 4G network (EPS) based on reasons such as mobility, radio conditions, service characteristics, and network commands.

Step 3. The terminal may perform an operation for attaching to the 4G network. The UE transmits an Attach request message to the MME of the 4G network. In this case, the request message indicates the type of PDN connectivity request included in the Attach or Attach (request type), and the UE moves from 5GS to the EPS during the Attach process to provide service. Session information (APN) to be continuously received may be included. Specifically, the terminal may additionally include the ID of the session used in 5GS in the PCO inserted in the Attach request message.

Step 4. The MME selects PGW-C + SMF using PGW information (more specifically PGW-C + SMF) among subscription information received from APN and HSS/UDM received from the terminal, and transmits a Create Session request message for session creation. I can. This message may include the ID of the terminal (subscriber) and an indicator indicating that the type of session creation is Handover. In addition, RAT Type information indicating that the wireless network to which the terminal is currently connected is 3GPP (or 4G LTE) may be included. During this process, the process of transmitting a message by the SGW between the MME and PGW-C + SMF is omitted.

Step 5. The PGW-C + SMF can process the received session creation request. If the session creation request message contains information indicating Handover, and a MA PDU session is created for the target terminal, PGW-C + SMF is an action to release the MA PDU session created by the N3GPP wireless network. Can be triggered. In particular, PGW-C + SMF at this time determines that the Handover request during session creation is interworking in the 3GPP network (5GS and EPS), not the handover between the 3GPP and N3GPP wireless networks, using the RAT Type information included in the request message. I can.

Step 6. PGW-C + SMF may transmit a response to the session creation request.

Step 7. The rest of the Attach process can be performed.

Step 8. If an additional PDU session remains in addition to the PDU session handed over to the EPS during the attach process by the terminal, the terminal may perform a process for handing over the session to the EPS for the remaining sessions. More specifically, the UE sends a PDN connection creation request to the MME, includes session information (APN) to continuously receive services from 5GS to EPS, and may include handover of the type of the generated request. In addition, the terminal may additionally include the ID of the session used in 5GS in the PCO inserted in the request message.

Step 9. The MME selects PGW-C + SMF using PGW information (more specifically PGW-C + SMF) among subscription information received from APN and HSS/UDM received from the terminal, and transmits a Create Session request message for session creation. I can. This message may include the ID of the terminal (subscriber) and an indicator indicating that the type of session creation is Handover. In addition, RAT Type information indicating that the wireless network to which the terminal is currently connected is 3GPP (or 4G LTE) may be included. During this process, the process of transmitting a message by the SGW between the MME and PGW-C + SMF is omitted.

Step 10. The PGW-C + SMF can process the received session creation request. If the session creation request message contains information indicating Handover, and a MA PDU session is created for the target terminal, PGW-C + SMF is an action to release the MA PDU session created by the N3GPP wireless network. Trigger. In particular, PGW-C + SMF at this time determines that the Handover request during session creation is interworking in the 3GPP network (5GS and EPS), not the handover between the 3GPP and N3GPP wireless networks, using the RAT Type information included in the request message. I can.

Step 11. PGW-C + SMF may transmit a response to the session creation request.

Step 12. The remaining PDN Connection creation process may be performed.

9 is a diagram illustrating an NF (AMF) operation of a network according to another disclosure of the present invention.

Step 1. The AMF may receive a registration request message for a specific terminal (subscriber). In the present disclosure, it is assumed that the UE supports the ATSSS function (ie, has Capability for ATSSS).

Step 2. The AMF may determine whether 4G network (EPS) interworking is supported for the corresponding terminal. This may be determined in consideration of whether the terminal has E-UTRAN support capability, the EPS interworking scheme supported by the terminal, whether the NW supports EPS interworking, and whether EPS interworking is allowed according to the subscription type. If EPS interworking is supported, it can transition to step 3, otherwise, it can transition to step 5.

Step 3. If EPS interworking support is required for the corresponding terminal, an EPS interworking method supported by the NW may be determined. For the target, Interworking with N26 interface (ie, N26 interface between MME and AMF is supported) and Interworking without N26 interface (ie, N26 interface between MME and AMF is not supported) may be considered. If EPS interworking with N26 support is not possible, it can transition to step 4.

Step 4. If EPS interworking with N26 support for the terminal is not possible, even if ATSSS is supported in the network and AMF, it may be determined that the terminal does not support ATSSS.

Step 5. The AMF may determine whether the NW supports ATSSS.

Step 6. The AMF may transmit a Registration Response to the terminal including whether or not the ATSSS determined in steps 4 and 5 is supported. If ATSSS is not supported, a separate ATSSS support indicator may not be included, or an explicit indicator indicating that ATSSS is not supported may be included. On the other hand, the NW (AMF) can determine whether to prioritize EPS Interworking or ATSSS use in a situation in which EPS Interworking and ATSSS cannot be applied at the same time (i.e., ATSSS is supported but only EPS Interworking without N26 is supported). At this time, the AMF may consider the usage type of the terminal (i.e., whether it is Voice Centric or Data Centric), and in the case of Voice Centric, EPS Interworking may be prioritized, and in the case of Data Centric, ATSSS use may be prioritized. Alternatively, the AMF can determine which support is supported by the operator's configuration or a separate operator setting. If the use of EPS Interworking is prioritized, the AMF informs that the registration response sent to the terminal supports EPS Interworking without N26, and the ATSSS may notify that it is not supported. Conversely, in case of prioritizing the use of ATSSS, ATSSS is supported and EPS interworking is not supported in the registration response.

Meanwhile, when determining whether the IMS-based voice service is supported for the terminal, the NW (AMF) may consider the capability of the terminal and the configuration of the NW together. If, in the configuration of the NW, it is impossible to provide IMS voice service through the wireless network to which you are currently connected, EPS Interworking with N26 interface is not supported, and only N26 interface without EPS interworking is supported, the terminal will send 5GMM Information to the Registration Request message. When the Handover Attach is notified as not supported, the support of IMS voice over PS session over 3GPP access among 5GS network feature support of the Registration response message sent to the terminal may be responded as not supported. The terminal receiving the registration response from the NW should first access other wireless networks (4G or 3G) to receive voice service if it has the Usage Type of Voice Centric and receives IMS Voice over PS session without support. You can try.

10 is a diagram illustrating an operation of a terminal supporting ATSSS in another disclosure of the present invention.

Step 1. The terminal may receive a registration response message from the AMF.

Step 2. The terminal may determine whether the NW supports ATSSS through the response message received from the AMF. If the NW supports ATSSS, it may transition to step 3, otherwise, it may transition to step 5.

Step 3. If the NW supports ATSSS, the terminal may determine whether EPS interworking is required or what an interworking support method is. This means whether the UE has E-UTRAN support capability, whether the NW supports EPS interworking, and the method supported by the NW is Interworking with N26 interface (i.e., N26 interface is supported between MME and AMF) and Interworking without N26 interface ( That is, whether the N26 interface is not supported between the MME and the AMF) can be considered. If it is necessary to apply EPS interworking to the terminal, but if only EPS interworking with without N26 is supported in the NW, the transition may be made to step 5, otherwise, the transition to step 4 may be performed.

Step 4. If the UE does not require EPS interworking or does not support EPS access, or if the NW supports EPS interworking with N26, the UE may determine that ATSSS can be used. Thereafter, the terminal may perform an ATSSS operation (request for adding or modifying a MA PDU session).

Step 5. If only N26 without interworking is supported, the UE may determine that ATSSS cannot be used even if the NW announces ATSSS support. Thereafter, the UE must not perform the ATSSS operation (request for adding or modifying a MA PDU session).

On the other hand, in a situation in which the UE cannot use EPS Interworking and ATSSS at the same time (i.e., when ATSSS is supported, but is connected to a network that supports only EPS Interworking without N26), it may determine whether to prioritize EPS Interworking or ATSSS use. This may be determined in consideration of the usage type of the terminal (that is, whether it is Voice Centric or Data Centric), or may be determined by the local configuration of the terminal or a separate user setting (such as input through a user interface). In the case of Voice Centric, the UE may preferentially consider EPS Interworking, and in the case of Data Centric, use of ATSSS may be prioritized.

On the other hand, when determining whether to use the NW and IMS-based voice service, the terminal may consider the capability of the terminal and the configuration of the NW together. If the NW received the support of IMS voice over PS session over 3GPP access through 5GS network feature support during the Registration response, Interworking without N26 interface supported among EPS interworking support methods was received as Supported. If the handover (HO Attach) function is not supported, the terminal may determine that it is impossible to use the IMS-based voice service in the 5G network. In this case, if the terminal is Voice Centric, it may attempt to first access another wireless network (4G or 3G) for receiving a voice service.

It should be noted that the configuration diagrams illustrated in FIGS. 1 to 10, an exemplary diagram of a control/data signal transmission method, an exemplary diagram of an operation procedure, and a configuration diagram are not intended to limit the scope of the present disclosure. That is, it should not be construed that all components, entities, or steps of operation described in FIGS. 1 to 10 are essential components for the implementation of the disclosure, and including only some components does not impair the essence of the disclosure. Can be implemented within

The operations of the base station or the terminal described above can be realized by having a memory device storing the corresponding program code in an arbitrary configuration unit in the base station or terminal device. That is, the control unit of the base station or the terminal device may execute the above-described operations by reading and executing the program code stored in the memory device by the processor or CPU (Central Processing Unit).

Various components of an entity, a base station, or a terminal device, and a module described in this specification are hardware circuits, for example, a complementary metal oxide semiconductor-based logic circuit, and firmware. And, it may be operated using hardware circuitry such as a combination of software and/or hardware and firmware and/or software embedded in a machine-readable medium. As an example, various electrical structures and methods may be implemented using transistors, logic gates, and electrical circuits such as application-specific semiconductors.

Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, various modifications are possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure is limited to the described embodiments and should not be defined, and should be determined by the scope of the claims and equivalents as well as the scope of the claims to be described later.

Claims (1)

In the control signal processing method in a wireless communication system,
Receiving a first control signal transmitted from a base station;
Processing the received first control signal; And
And transmitting a second control signal generated based on the processing to the base station.

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