KR102287166B1 - Method and Apparatus for Establishing Bearer in 5G NSA Environment - Google Patents

Abstract

The present invention relates to a method for establishing a bearer in a 5G NSA environment and an apparatus and system therefor, and a first base station providing Long Term Evolution (LTE) coverage and a second base station providing NR (New Radio) coverage according to an embodiment A bearer establishment method in a 5G Non-StandAlone (NSA) system including two base stations includes the steps of: receiving a service request message from a terminal through the first base station in a Mobility Management Entity (MME); Checking whether the first base station is connected to the second base station and as a result of the check, if the first base station is connected to the second base station, performing, in the first base station, a measurement procedure with the terminal; Determining whether the terminal is in the 5G service area based on the measurement procedure in the first base station, and if the determination result is in the 5G service area, establishing a 5G bearer through the second base station. there is.

Description

Method and apparatus for establishing a bearer in 5G NSA environment {Method and Apparatus for Establishing Bearer in 5G NSA Environment}

The present invention relates to a mobile communication system, and more particularly, to a method and apparatus for establishing a bearer capable of reducing a signal processing load in a 5G NSA environment.

In general, mobile communication systems have been developed for the purpose of providing communication while securing user mobility. Such a mobile communication system has reached a stage where it can provide not only voice and video communication but also high-speed data communication service thanks to the rapid development of technology.

Recently, it is widely utilized 4G LTE-A (Long Term Evolution -Advanced) system based on the standard specification 3GPP (3 ^rd Generation Partnership Project) is commercially available. In addition, as a next-generation mobile communication system, 5G standardization, which is called NR (New Radio) in 3GPP, is actively progressing and is about to be commercialized.

However, in a 5G Non-StandAlone (NSA) environment where LTE Radio and New Radio coexist, it is important to minimize processing delay due to interworking between base stations supporting different radio access technologies.

In particular, in the prior art, even though the 5G NSA terminal is currently located in the 5G service area, when the terminal requests a data service in an idle state, the 4G base station first creates a 4G bearer and then performs a procedure of changing to a 5G bearer, so that the base station-MME There was a problem in that unnecessary signaling between -S/PGW was generated.

The present invention has been devised to solve the problems of the prior art, and an object of the present invention is to provide a method for establishing a bearer in a 5G NSA environment, and an apparatus and system therefor.

Another object of the present invention is to provide a bearer establishment method capable of minimizing call processing delay in a 5G NSA system, and an apparatus and system therefor.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be able

The present invention provides a method for establishing a bearer in a 5G NSA environment, and an apparatus and system therefor.

A method for establishing a bearer in a 5G Non-StandAlone (NSA) system including a first base station providing Long Term Evolution (LTE) coverage and a second base station providing New Radio (NR) coverage according to an embodiment is MME ( In the Mobility Management Entity), receiving a service request message from a terminal through the first base station and confirming, in the first base station, whether the first base station is connected to the second base station, and as a result of the check, the When the first base station is connected to the second base station, the first base station performs a measurement procedure with the terminal and the first base station determines whether the terminal is in a 5G service area based on the measurement procedure and, if it is in the 5G service area as a result of the determination, establishing a 5G bearer through the second base station.

In an embodiment, the service request message may be received in a state transitioned to an idle state after an access procedure for the terminal is completed.

In an embodiment, when the initial context setup request message is received from the MME, the first base station may check whether the first base station is connected to the second base station.

In an embodiment, the measurement procedure may include transmitting a measurement configuration message from the first base station to the terminal and receiving a measurement report message including a measurement result from the terminal.

In an embodiment, the measurement result may include at least one of Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and Signal to Interference Noise Ratio (SINR) for each target cell.

In an embodiment, the step of establishing the 5G bearer includes, in the first base station, transmitting an initial context setup response message including an IP address corresponding to the second base station to the MME, and in the MME, the second Transmitting a bearer modification request message including an IP address corresponding to the base station to a Serving/Packet GateWay (S/PGW) and transmitting a bearer modification response message to the MME in the S/PGW. .

A method for establishing a bearer of a first base station providing Long Term Evolution (LTE) coverage in a 5G Non-StandAlone (NSA) environment according to another embodiment transmits a service request message received from a terminal to a Mobility Management Entity (MME) and receiving an initial context establishment request message from the MME, and confirming whether it is connected to a second base station providing NR (New Radio) coverage. Performing a measurement procedure with the terminal and determining whether the terminal is in the 5G service area based on the measurement procedure, and if the determination result is in the 5G service area, 5G through the second base station in conjunction with the MME It may include the step of establishing a bearer.

In an embodiment, the service request message may be received in a state transitioned to an idle state after an access procedure for the terminal is completed.

In an embodiment, the measurement procedure may include transmitting a measurement configuration message from the first base station to the terminal and receiving a measurement report message including a measurement result from the terminal.

In an embodiment, the measurement result may include at least one of Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and Signal to Interference Noise Ratio (SINR) for each target cell.

In an embodiment, the step of establishing the 5G bearer includes transmitting an initial context setup response message including an IP address corresponding to the second base station to the MME and, in the MME, an IP address corresponding to the second base station It may include transmitting a bearer modification request message including , to a Serving/Packet GateWay (S/PGW), and transmitting a bearer modification response message from the S/PGW to the MME.

5G Non-StandAlone (NSA) system according to another embodiment provides LTE (Long Term Evolution) coverage, and determines whether a terminal transitioned to an idle state after connection completion is located in the 5G service area is located in the 5G service area through a measurement procedure. When receiving the service request message transmitted by the terminal from the first base station for controlling 5G bearer setup, the second base station providing NR (New Radio) coverage, and the first base station, an initial context setup request message to the first base station It may include a Mobility Management Entity (MME) that controls to initiate the measurement procedure by sending

In an embodiment, the measurement procedure may include transmitting a measurement configuration message from the first base station to the terminal and receiving a measurement report message including a measurement result from the terminal.

In an embodiment, the measurement result may include at least one of Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and Signal to Interference Noise Ratio (SINR) for each target cell.

In an embodiment, if the first base station determines that the terminal is located in the 5G service area, it may transmit an initial context setup response message including an IP address corresponding to the second base station to the MME.

In an embodiment, when the MME receives the initial context establishment response message from the first base station, it transmits a bearer modification request message including an IP address corresponding to the second base station to the S/PGW, and transmits a bearer modification response message The 5G bearer may be established by receiving from the S/PGW.

Another embodiment of the present invention may provide a program for executing any one of the above methods and a computer-readable recording medium in which the program is recorded.

Aspects of the present invention are only some of the preferred embodiments of the present invention, and various embodiments in which the technical features of the present invention are reflected are detailed descriptions of the present invention that will be described below by those of ordinary skill in the art. It can be derived and understood based on

The effect on the method and apparatus according to the present invention will be described as follows.

The present invention has the advantage of providing a method for establishing a bearer in a 5G NSA environment, and an apparatus and system for the same.

In addition, the present invention has the advantage of providing a bearer establishment method capable of minimizing call processing delay and load in a 5G NSA environment, and an apparatus and system therefor.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be.

The accompanying drawings are provided to help understanding of the present invention, and provide embodiments of the present invention together with detailed description. However, the technical features of the present invention are not limited to specific drawings, and features disclosed in each drawing may be combined with each other to constitute a new embodiment.
1 is a configuration diagram of an LTE network according to an embodiment.
2 is a diagram for explaining the structure of an SA and NSA (EN-DC) system supporting the use of 5G NR according to an embodiment.
3 is a diagram for describing DC technology in an LTE system according to an embodiment.
4 is a diagram for explaining a 5G NSA structure according to an embodiment.
5A is a diagram for explaining a terminal access procedure to a mobile communication system according to an embodiment.
5B is a diagram for explaining a procedure for changing a bearer to a 5G base station in a state in which initial access is completed through a 4G base station according to an embodiment.
6A is a diagram for explaining a procedure for transmitting data again after an access terminal transitions to an idle state according to an embodiment.
6B is a diagram for explaining a procedure for changing to a 5G bearer in a state in which an origination procedure is completed through 4G bearer establishment according to an embodiment.
7 is a diagram for explaining a data transmission procedure in a 5G NSA system according to an embodiment.

Hereinafter, an apparatus and various methods to which embodiments of the present invention are applied will be described in more detail with reference to the drawings. The suffixes "module" and "part" for the components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have a meaning or role distinct from each other by themselves.

In the description of the embodiment, in the case where it is described as being formed on "upper (upper) or lower (lower)" of each component, the upper (upper) or lower (lower) is in direct contact with each other or One or more other components are all formed by being disposed between two components. In addition, when expressed as “upper (upper) or lower (lower)”, it may include not only the upper direction but also the meaning of the lower direction based on one component.

1 is a configuration diagram of an LTE network according to an embodiment.

Referring to FIG. 1, referring to FIG. 1, the LTE network includes a User Equipment (UE) 10, an Evolved Node B (eNB, 20), a Serving Gateway (S-GW, 30), and a Packet Data Network Gateway (P-GW). , 40), MME (Mobility Management Entity, 50), HSS (Home Subscriber Server, 60), SPR (Subscriber Profile Repository, 70), OFCS (Offline Charging System, 80), OCS (Online Charging System, 90), PCRF (Policy and Charging Rule Function, 100) may be configured to include.

The UE 10 is an LTE user terminal, and the LTE Uu interface 15 is connected to the eNB 20 . Here, the LTE Uu interface 15 is a wireless interface, and a control plane for transmitting and receiving control messages and a user plane for providing user data are defined.

The eNB 20 is a device that provides a radio interface to the UE 10, and provides radio resource management functions such as radio bearer control, radio admission control, dynamic radio resource allocation, load balancing, and inter-cell interference control. do.

The S-GW 30 is an end of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and an Evolved Packet Core (EPC), and an anchoring point during handover between eNBs 20 and handover between 3GPP systems. do. Here, the E-UTRAN is composed of at least one eNB 20 , and the EPC is composed of the S-GW 30 , the P-GW 40 and the MME 50 .

The P-GW 40 connects the UE 10 with an external Packet Data Network (PDN) 110 and performs a packet filtering function.

In addition, the P-GW 40 allocates an IP address to the UE 10 and operates as a mobility anchoring point during handover between the 3GPP system and the non-3GPP system.

In particular, the P-GW 40 receives the Policy and Charging Control (PCC) rule from the PCRF 100, applies it to the corresponding service flow, and provides a charging function for each UE 10/SDF (Service Date Flow). do.

The HSS 60 provides user authentication information and a user profile to the MME 50 as a database in which a user profile is stored.

The SPR 70 provides subscriber and subscription-related information to the PCRF 100, and the PCRF 100 generates a subscriber-based PCC rule using the subscriber and subscription-related information.

OFCS 80 provides charging data record (CDR)-based charging information.

The OCS 90 provides a charging function based on volume, time, and event through real-time credit control.

The PCRF 100 is an entity that performs policy and charging control, and provides a policy control decision and charging control function. The PCC rule generated in the PCRF 100 is transmitted to the P-GW 40 .

Hereinafter, an interface between elements constituting an LTE network will be briefly described.

The LTE-Uu 15 provides a control plane and a user plane as a radio interface between the UE 10 and the eNB 20 .

The S1-U 25 is an interface between the eNB 20 and the S-GW 30 and provides a user plane. In this case, GTP tunneling per bearer is provided.

S5 35 is an interface between the S-GW 30 and the P-GW 40, and provides a control plane and a user plane. In this case, the user plane provides GTP tunneling for each bearer, and the control plane provides GTP tunnel management.

The SGi 45 defines a user plane and a control plane as an interface between the P-GW 40 and the PDN 110 . In the user plane, an IETF-based IP packet forwarding protocol is used, and in the control plane, protocols such as DHCP and RADIUS/Diameter are used.

The S11 55 is an interface between the MME 50 and the S-GW 30 in which a control plane is defined, and GTP tunneling is provided per bearer.

The X2 65 is an interface between two eNBs 20 or two base stations supporting RAT (Radio Access Technology) between each other, and provides a control plane and a user plane. In the control plane, the X2-AP protocol is used, and in the user plane, GPRS Tunneling Protocol (GTP) tunneling is provided per bearer for data forwarding during X2 handover.

S6a (75) is provided with a control plane as an interface between the HSS (60) and the MME (50), and is used to exchange UE subscription information and authentication information.

The Gx 85 is an interface between the PCRF 100 and the P-GW 40, a control plane is defined, and is used to transmit a policy control rule and a charging rule for QoS (Quality of Service) policy and charging control. .

Sp (95) is an interface between the SPR (70) and the PCRF (100), a control plane is defined, and is used to transmit a user profile.

Gz 105 is an interface between OFCS 80 and P-GW 40, a control plane is defined, and is used for CDR transmission from P-GW 40 to OFCS 80.

Gy 115 is an interface between the OCS 90 and the P-GW 40, a control plane is defined, and is used for real-time credit control information exchange.

The S1-AP 125 is an interface between the eNB 20 and the MME 50, a control plane is defined, and is used for exchanging control information for mobility management.

2 is a diagram for explaining the structure of an SA and NSA (EN-DC) system supporting the use of 5G NR according to an embodiment.

In the process of discussing the 5G structure at the general meeting of the 3GPP standards body, it is said that it is necessary to research and create standard technologies that can create new services and the demand to satisfy the telecommunication operators of countries with rapid commercialization demand before 2020. A request was made.

In the process of discussing these two opposing needs, various structural candidates were discussed, and as a result of the discussion, a new NR (New Radio) technology for operators who want to be commercialized quickly is used together with the existing LTE system to provide LTE coverage and NR coverage at the same time. A non-standalone (NSA) structure providing only 　 ((b) of FIG. 2) and a stand-alone (SA) structure providing only NR coverage ((a) of FIG. 2) were introduced.

The following three types of base stations may be defined in the SA system and the NSA system supporting the use of 5G NR of FIG. 2 .

1) eNB: Base station used in LTE system supporting interworking between LTE technology and EPC (Enhanced Packet Core)

2) gNB: Next-generation base station supporting NR technology and interworking with 5G Core

3) en-gNB: A new type of base station that supports NR technology and interworking with 5G Core while interworking with EPC, the core of LTE system, and eNB, which is the base station

Among the three base station types, gNB is used only in the 5G SA structure as shown in FIG. 2(a).

This is because, in the 5G SA structure, the UE uses only the gNB resources controlled by the NR technology.

In contrast, the UE in the 5G NSA structure uses not only the resources of the eNB supporting the LTE technology, but also the resources of the en-gNB that supports the NR technology while interworking with the eNB and the EPC.

As shown in (b) of FIG. 2, a technology in which a terminal supporting one or more RX/TX simultaneously uses resources controlled by one or more base stations is called Dual Connectivity (DC). The 5G NSA structure is DC defined by the 3GPP standard organization. based on technology.

3 is a diagram for describing DC technology in an LTE system according to an embodiment.

DC technology, which is the basis of the 5G NSA structure, was also introduced in 3GPP Release-12 before 5G NR was defined.

At that time, mobile carriers that introduced unlimited rates for LTE experienced capacity shortages in hot spots, such as large cities, where many users were concentrated. To address this capacity shortage, new frequencies available for LTE had to be allocated.

At that time, the possibility of using a frequency of the 3.5 GHz band was mentioned in some countries.

The 3.5 GHz frequency band is a higher frequency band than the frequency band used in the existing LTE.

An LTE base station using a 3.5 GHz frequency band, which is a high frequency band, becomes a small cell having a smaller coverage than an LTE base station using an existing frequency.

As shown in FIG. 3 , in the LTE DC structure, a small cell LTE base station using a higher frequency than the existing one, that is, a Secondary Node (SN), is installed in a hotspot area where the capacity shortage occurs. Accordingly, in the LTE DC structure, there may be an overlapping region in which a resource controlled by a macro base station, that is, a Master Node (MN) and a resource controlled by an SN, can be simultaneously used in the existing LTE base station.

In the LTE DC structure, the UE located in this overlapping area uses the radio resources of both nodes to receive a communication service with a higher capacity than when only the resources provided by the MN are used, effectively solving the problem of insufficient capacity in the hotspot. could be

5G NSA (Non-StandAlone) is an extension of the MN or SN to support NR resources in addition to LTE resources in the DC structure introduced in 3GPP release-12.

4 is a diagram for explaining a 5G NSA structure according to an embodiment.

The 5G NSA structure on the current 3GPP standard not only supports the use of NR in the Master Node (MN) or the Secondary Node (SN), but also supports the use of the 5G Core or EPC in the core network.

The standard is defined to support various combinations of NSA structures, but in reality, in the case of a telecommunication service provider using an LTE system consisting of EPC and LTE Macro base stations as a nationwide network, a combination structure that makes the most of the existing LTE system is used for fast 5G It is being considered for commercialization.

As an example, the 5G NSA structure may be the structure of FIG. 4 using the EPC of the LTE system as the core network, the eNB as the LTE base station as the MN, and the en-gNB as the NR base station as the SN.

An eNB operating as an MN may create an S1-MME control connection with the control entity MME of the EPC, which is the core of the LTE system, and relay transmission/reception of a NAS (Nan Access Stratum) control message between the MME and the UE.

In addition, the eNB may create a Radio Resource Control (RRC) connection with the UE using LTE radio technology, and may manage an RRC state based on the RRC connection.

The en-gNB operating as an SN may participate only in an additional data connection for high-capacity data transmission/reception, without being involved in the relaying of NAS messages and control connections related to EPC.

The en-gNB, which transmits and receives data through an additional data connection, can transmit/receive data to and from the EPC by using one of the following two paths, unlike the eNB, which is an MN.

The first path may be a PGW/SGW<-->eNB<-->en-gNB connection path for transmitting and receiving data through the eNB.

In the first path, the eNB, which is the MN, divides the first data directly transmitted to the UE using LTE radio resources and the second data transmitted to the UE using NR resources through en-gNB as a split node. can play a role.

The second path is a PGW/SGW<-->en-gNB connection path that transmits and receives data directly to and from the PGW/SGW.

In the second path, the SGW may serve as a split node that divides the first data transmitted and received with the UE through the eNB and the second data transmitted and received with the UE through the en-gNB.

Which one of the above two connection paths is used for data transmission/reception between the SN and the EPC may be determined by a person skilled in the art.

5A is a diagram for explaining a terminal access procedure to a mobile communication system according to an embodiment.

In the following description of the embodiment, the IP address assigned to the 4G base station 520 is 10.10.10.1, and the IP address assigned to the 5G base station 530 is 10.10.10.2.

Referring to FIG. 5A , when power is applied, the terminal 510 may transmit an Attach Request message for requesting a connection to a packet data network (PDN) to the MME 540 (S501).

Here, the access request message includes subscriber identification information-eg, International Mobile Station Identity (IMSI)-, cell identification information for identifying an accessed cell, information for identifying a PDN type, PCO=DNS Server IPv4 Address Request, etc. may include. However, the present invention is not limited thereto.

For example, when the terminal 510 is connected to the 4G base station 520, the 4G base station 520 identifies the Cell ID for identifying which cell the terminal 510 is connected to and which tracking area it is in. For TAI (Tracking Area Identifier) may be transmitted to the MME (540).

The MME 540 may perform a predetermined authentication procedure by interworking with the HSS 60 and the terminal 510 described in FIG. 1 , and upon completion of authentication, may perform a location update procedure in conjunction with the HSS 60 ( S502 ) ).

In the case of the authentication procedure, the MME 540 may request authentication information (AV; Authentication Vector) from the HSS 60 for authentication of the terminal 510 .

The HSS 60 may generate an AV for the corresponding terminal 510 and deliver it to the MME 540 . Here, AV may include RAND, AUTH, XRES, KASME, and the like.

When the MME 540 is ready to authenticate the UE 510 , the MME 540 may transmit a portion of the AV information received from the HSS 60 to the UE 510 . The terminal 510 may authenticate the 4G LTE network by comparing the AUTN among the AV information received from the MME 540 with the AUTN generated by the terminal 510 .

The terminal 510 transmits the RES generated by it to the MME 540, and the MME 540 compares the XRES received from the HSS 60 with the RES received from the terminal 510 to authenticate the terminal 510. can do.

Thereafter, the MME 540 and the terminal 510 may perform a predetermined security setting procedure for safely delivering a NAS (Non-Access Stratum) message in a wireless section.

In the case of the location update procedure, the MME 540 transmits a Location Update Request Message including at least IMSI and MME identifier to the HSS 60, IMSI, Subscribed APN corresponding to the IMSI, Subscribed P - A Location Update Answer Message including GW ID, Subscribed QoS Profile, etc. may be received from the HSS 60. may be performed.

In addition, when the location update request message is received, the HSS 60 refers to the internal database to identify the static IP address assigned to the IMSI, and transmits a location update response message including the identified static IP address to the MME 540 . may be

Through the location update procedure, the MME 540 registers with the HSS 60 which MME the terminal 510 is currently connected to, and the HSS 60 has a service profile corresponding to the corresponding IMSI (Service Profile) (or QoS Profile) may be extracted from the internal database and transmitted to the MME 540 .

Thereafter, the MME 540 may perform an Enhance Packet Session (EPS) bearer establishment procedure in conjunction with a Serving and Packet Gateway (S/PGW) 550 .

The MME 540 transmits a session establishment request message requesting session establishment for the corresponding IMSI to the Serving and Packet Gateway (S/PGW, 550), and a session establishment response message including the UE IP allocated in response to the corresponding IMSI. can be received (S503).

When the authentication and location update procedures are successfully completed, the MME 540 may transmit an InitialContextSetupRequest message indicating that the access request has been accepted to the 4G base station 520 (S504).

The 4G base station 520 transmits an Attach Accept message to the terminal 510 (S505), and completes the initial context setting including its IP address (10,10,10,1) for EPS bearer establishment. A (InitialContextSetupComplete) message may be transmitted to the MME 540 (S505).

The terminal 510 may transmit an Attach Complete message to the MME 540 in response to the access acceptance message (S507).

The MME 540 transmits a bearer modification request (Modify Bearer Request) message including the IP address (10,10,10,1) of the 4G base station 520 to the S/PGW 550, and the S/PGW 550 ) may set a bayer based on the received IP address (10, 10, 10, 1) of the 4G base station 520 (S508).

In this case, the established bearer is a DRB (Data Radio Bearer) tunnel between the UE 510 and the 4G base station 510, the eNB, the S1 GTP (GPRS Tunneling Protocol) tunnel between the eNB and the S-GW, and the S-GW and the P-GW. It may include an S5 GTP tunnel.

The IP packet transmitted by the terminal 510 is transmitted to the eNB, which is the 4G base station 520, through the DRB tunnel, and is transmitted from the eNB to the P-GW through the GTP tunnel. That is, the IP packet sent by the terminal 510 is always transmitted to the P-GW through the eNB regardless of the destination IP address.

When the bearer setup is completed, the initial access procedure through the 4G base station 520 of the terminal 510 is completed.

5B is a diagram for explaining a procedure for changing a bearer to a 5G base station in a state in which initial access is completed through a 4G base station according to an embodiment.

Referring to FIG. 5B , in a state in which the initial access of the terminal 510 through the 4G base station is completed, the 4G base station 520 may transmit a Measurement Configuration message to the terminal 510 ( S561 ).

The terminal 510 may perform measurement based on the measurement configuration parameter included in the measurement configuration message, and transmit a measurement report message including the measurement result to the 4G base station 520 (S562). ).

As an example, the measurement result may include a reference signal received power (RSRP), a reference signal received quality (RSRQ), and a signal to interference noise ratio (SINR) for each target cell.

The 4G base station 520 may determine whether the terminal 510 is in the 5G service area based on the measurement result included in the measurement report message (S563).

For example, when the quality of a signal received from the 5G base station 530 exceeds a predetermined reference value, the 4G base station 520 may determine that the terminal 510 is located in the 5G serviceable area.

As a result of the determination, if the terminal 510 is in the 5G service area, the 4G base station 520 changes the bearer established with the 4G base station to the 5G base station bearer IP address (10, 10, 10, 2) of the 5G base station 530 It may transmit an E-RAB modification indication (Enhanced Radio Access Bearer Modification Indication) message including to the MME 540 (S564).

The MME 540 transmits a bearer modification request (Modify Bearer Request) message including the IP address (10,10,10,2) of the 5G base station 530 to the S/PGW 550, and the S/PGW 550 ) may change the Bayer setting from 4G to 5G based on the received IP address (10, 10, 10, 2) of the 5G base station 530 (S565).

When the bearer setup for the 5G base station 530 is completed, the MME 540 may transmit an Enhanced Radio Access Bearer Modification Confirm message to the 4G base station 520 in response to the E-RAB modification indication message. There is (S566). In this case, the 4G base station 520 may release the 4G bearer established with the terminal 510 and establish a 5G bearer.

6A is a diagram for explaining a procedure for transmitting data again after an access terminal transitions to an idle state according to an embodiment.

Referring to FIG. 6A , after the access terminal transitions to the idle state, if there is data to be transmitted, the terminal 510 may generate a service request message and transmit it to the MME 540 ( S601 ).

The MME 640 may transmit an initial context setup request message to the 4G base station 620 (S602).

The 4G base station 620 may transmit an initial context setup response message including the IP address (10.10.10.1) of the 4G base station 620 to the MME 640 in response to the initial context setup request message (S603).

The MME 640 transmits a bearer modification request (Modify Bearer Request) message including the IP address (10,10,10,1) of the 4G base station 620 to the S/PGW 650, and the S/PGW 650 ) may establish a bearer based on the received IP address (10, 10, 10, 1) of the 4G base station 620 (S604).

In this case, the configured bearer may include a DRB tunnel between the UE 610 and the 4G base station 610, an eNB, an S1 GTP tunnel between the eNB and the S-GW, and an S5 GTP tunnel between the S-GW and the P-GW.

When the 4G bearer is established through steps 601 to 604, the calling procedure may be completed.

6B is a diagram for explaining a procedure for changing to a 5G bearer in a state in which an origination procedure is completed through 4G bearer establishment according to an embodiment.

Referring to FIG. 6B, as described in FIG. 6A, in a state in which the transmission procedure is completed through 4G bearer setup, the 4G base station 620 may transmit a Measurement Configuration message to the terminal 610 (S661). .

The terminal 610 may perform measurement based on the measurement configuration parameter included in the measurement configuration message, and transmit a measurement report message including the measurement result to the 4G base station 620 (S662). ).

As an example, the measurement result may include a reference signal received power (RSRP), a reference signal received quality (RSRQ), and a signal to interference noise ratio (SINR) for each target cell.

The 4G base station 620 may determine whether the terminal 610 is in the 5G service area based on the measurement result included in the measurement report message (S663).

For example, when the quality of the signal received from the 5G base station 630 exceeds a predetermined reference value, the 4G base station 620 may determine that the terminal 610 is located in the 5G serviceable area.

As a result of the determination, if the terminal 610 is in the 5G service area, the 4G base station 620 includes the IP address (10,10,10,2) of the 5G base station 630 to change the preset 4G bearer to the 5G bearer. It may transmit an E-RAB modification indication (Enhanced Radio Access Bearer Modification Indication) message to the MME 640 (S664).

The MME 640 transmits a bearer modification request (Modify Bearer Request) message including the IP address (10,10,10,2) of the 5G base station 630 to the S/PGW 650, and the S/PGW 650 ) may change the Bayer setting from 4G to 5G based on the received IP address (10, 10, 10, 2) of the 5G base station 630 (S665).

When the bearer setup for the 5G base station 630 is completed, the MME 640 may transmit an Enhanced Radio Access Bearer Modification Confirm message to the 4G base station 620 in response to the E-RAB modification indication message. There is (S666). In this case, the 4G base station 620 may release the 4G bearer established with the terminal 610 and establish a 5G bearer.

However, the procedure for changing to a 5G bearer according to the embodiment of 6b is a procedure of first creating a 4G bearer and then changing to a 5G bearer whenever data transmission is required even though the terminal 610 is currently located in the 5G service area. Since it is performed, there is a problem in that unnecessary signaling between the base station-MME-S/PGW is generated.

7 is a diagram for explaining a data transmission procedure in a 5G NSA system according to an embodiment.

Referring to FIG. 7 , the terminal 710 may transition back to the idle state after completing the initial access through the procedure of FIG. 5A .

When there is data to be transmitted, the terminal 710 in the idle state may generate a service request message and transmit it to the MME 740 (S701).

The MME 740 may transmit an initial context setup request message to the 4G base station 720 (S702).

The 4G base station 720 may determine whether it is interworking with the 5G base station 730 (S703).

As a result of the determination, when interworking with the 5G base station 730, the 4G base station 720 may transmit a Measurement Configuration message to the terminal 710 (S704).

The terminal 710 measures the strength of the 5G base station signal based on the measurement configuration parameter included in the measurement configuration message, and transmits a measurement report message including the measurement result to the 4G base station 720. It can be (S705).

As an example, the measurement result may include a reference signal received power (RSRP), a reference signal received quality (RSRQ), and a signal to interference noise ratio (SINR) for each measurement target cell.

The 4G base station 720 may determine whether the terminal 710 is in the 5G service area based on the measurement result included in the measurement report message (S706).

As a result of the determination, when the terminal 710 is located in the 5G service area, the 4G base station 720 responds to the initial context setup request message including the IP address (10.10.10.2) of the 5G base station 730 in response to the initial context setup response. The message may be transmitted to the MME 740 (S707).

The MME 740 transmits a bearer modification request (Modify Bearer Request) message including the IP address (10,10,10,2) of the 5G base station 730 to the S/PGW 750, and the S/PGW 750 ) may change the bearer setup for data transmission from the 4G base station 720 to the 5G base station 720 based on the received IP address (10, 10, 10, 2) of the 5G base station 730 (S708) .

As described in FIG. 7 above, when the terminal 710 starts data transmission in an idle state, the 4G base station 720 does not unconditionally establish a bearer to the 4G base station 720 in the EPS bearer establishment step, but is a 5G base station. It can be checked whether it is connected to (730).

As a result of the check, when the 4G base station 720 and the 5G base station 730 are connected, the 4G base station 720 may check whether the terminal 720 is in a state in which the 5G service can be provided through a measurement procedure.

The 4G base station 720 can remove the unnecessary bearer reconfiguration procedure of FIG. 6B by controlling so that the 5G bearer is established immediately when the 5G service is available.

Through the above embodiments, the present invention has an advantage in that it is possible to provide an optimized method for establishing a bearer capable of minimizing call processing delay and load in a 5G NSA environment, and an apparatus and system for the same.

The methods according to the above-described embodiments may be produced as a program to be executed by a computer and stored in a computer-readable recording medium, and examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape. , floppy disks, optical data storage devices, and the like.

It is apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention.

Accordingly, the above detailed description should not be construed as restrictive in all respects but as exemplary. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention.

Claims (17)

A method for establishing a bearer in a wireless communication system including a first base station providing a first frequency service area and a second base station providing a second frequency service area, the method comprising:
Receiving a service request message from a terminal through the first base station in a mobility management device (MME, Mobility Management Entity);
transmitting an initial context setup request message from the mobility management device to the first base station;
checking, at the first base station, whether the first base station is connected to the second base station;
As a result of the check, if the first base station is connected to the second base station, performing, in the first base station, a measurement procedure between the terminal and the second base station;
determining, in the first base station, whether the terminal is in the second frequency service area based on the measurement procedure; and
If it is in the second frequency service area as a result of the determination, the first base station transmits an initial context setup response message including an IP address corresponding to the second base station to the mobility management device, Step 2 to establish a frequency bearer
A bearer establishment method in a wireless communication system comprising a. According to claim 1,
The method for establishing a bearer in a wireless communication system, wherein the service request message is received in a state transitioned to an idle state after an access procedure for the terminal is completed. According to claim 1,
When the first base station receives an initial context setup request message from the mobility management device, the first base station determines whether the first base station is connected to the second base station. 4. The method of claim 3,
The measurement procedure is
transmitting a measurement configuration message from the first base station to the terminal; and
Receiving a measurement report message including a measurement result from the terminal
A bearer establishment method in a wireless communication system comprising a. 4. The method of claim 3,
The measurement result includes at least one of Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and Signal to Interference Noise Ratio (SINR) for each target cell. According to claim 1,
The step of establishing the second frequency bearer comprises:
transmitting, by the mobility management device, a bearer modification request message including an IP address corresponding to the second base station to a Serving/Packet GateWay (S/PGW); and
Transmitting, in the S/PGW, a bearer modification response message to the mobility management device;
A bearer establishment method in a wireless communication system comprising a. A method for establishing a bearer of a first base station providing a first frequency service area in a second frequency non-standalone mode (NSA, Non-StandAlone) environment, the method comprising:
transmitting the service request message received from the terminal to the mobility management device;
receiving an initial context setup request message from the mobility management device;
checking whether a second base station is connected to a second base station providing a second frequency service area;
performing a measurement procedure between the terminal and the second base station when connected to the second base station as a result of the check;
determining whether the terminal is in the second frequency service area based on the measurement procedure; and
As a result of the determination, if in the second frequency service area, an initial context setup response message including an IP address corresponding to the second base station is sent to the mobility management device so that a second frequency bearer is established through the second base station. transmitting;
How to set up a bearer, including 8. The method of claim 7,
The service request message is received in a state transitioned to the idle state after the access procedure to the terminal is completed. 8. The method of claim 7,
The measurement procedure is
transmitting a measurement configuration message from the first base station to the terminal; and
Receiving a measurement report message including a measurement result from the terminal
How to set up a bearer, including 10. The method of claim 9,
The measurement result includes at least one of Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and Signal to Interference Noise Ratio (SINR) for each target cell. 8. The method of claim 7,
The step of establishing the second frequency bearer comprises:
transmitting an initial context setup response message including an IP address corresponding to the second base station to the mobility management device;
transmitting, by the mobility management device, a bearer modification request message including an IP address corresponding to the second base station to a Serving/Packet GateWay (S/PGW); and
Transmitting, in the S/PGW, a bearer modification response message to the mobility management device;
How to set up a bearer, including A computer-readable recording medium in which a program for executing the method according to any one of claims 1 to 11 is recorded. a first base station that provides a first frequency service area and controls setting of a second frequency bearer by determining whether a terminal, which has transitioned to an idle state after connection completion, is located in a second frequency service area through a measurement procedure;
a second base station providing the second frequency service area;
a mobility management device for controlling to start the measurement procedure by transmitting an initial context establishment request message to the first base station upon receiving the service request message transmitted by the terminal from the first base station; and
and a Serving/Packet Gateway (S/PGW) for changing bearer settings in conjunction with the mobility management device,
The first base station,
Upon receiving the initial context setup request message from the mobility management device, a measurement procedure between the terminal and the second base station is performed, and an initial context setup response message including an IP address corresponding to the second base station is transmitted according to the measurement result. A wireless communication system that transmits to a mobility management device. 14. The method of claim 13,
The measurement procedure is
transmitting a measurement configuration message from the first base station to the terminal; and
Receiving a measurement report message including a measurement result from the terminal
A wireless communication system comprising a. 15. The method of claim 14,
The measurement result includes at least one of Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and Signal to Interference Noise Ratio (SINR) for each target cell. 14. The method of claim 13,
When the first base station determines that the terminal is located in the second frequency service area, the first base station transmits an initial context setup response message including an IP address corresponding to the second base station to the mobility management device. 17. The method of claim 16,
When the mobility management device receives the initial context establishment response message from the first base station, it transmits a bearer modification request message including an IP address corresponding to the second base station to the S/PGW, and transmits the bearer modification response message to the S/PGW. A wireless communication system for receiving from S/PGW and establishing the second frequency bearer.

Images