Method and apparatus for redundant transmission for ultra-reliable services in 5G wireless network system

The present disclosure relates to communication methods and systems for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. Disclosed are reliable transmission methods for ultra-reliable low-latency communication (URLLC) in 5G next-generation core networks, which provide methods of redundant transmission through a plurality of transmission paths in order to perform transmission between radio access networks (RANs) through ultra-reliable transmission in the core network. The disclosure also provides simple multiple path transmission and multiple path transmission using an intermedia user plane function (I-UPF) according to the deployment environment of a network router.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2018-0057796, filed on May 21, 2018, in the Korean Intellectual Property Office, the disclosure of which is herein incorporated by reference in its entirety.

BACKGROUND

The disclosure relates to a 5G wireless communication network system and, more specifically, to a redundant transmission method for an ultra-reliable service.

2. Description of Related Art

A wireless communication system defines a NextGen core (NG core), which is a new core network, as it evolves from a 4G system to a 5G system. The new core network virtualizes all existing network entities (NEs) into network functions (NFs). In addition, a mobility management entity (MME) function is separated into mobility management (MM) and session management (SM), and terminal mobility management has levels according to the usage type of terminal.

The 5G wireless communication system must support various terminals, such as enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine type communications (mMTC). The respective terminals/services above have different requirements for the core network. The eMBB service requires a high data rate, and the URLLC service requires high stability and low latency.

Among them, the URLLC service pursues the highest service stability. That is, when data is transmitted, the data must be successfully transmitted with a reliability of 99.99% or more. To this end, there are proposals for a method of sending data through redundant transmission, thereby obtaining a high data transmission success rate, even with additional costs.

SUMMARY

The disclosure provides methods for the ultra-reliable data transmission when a user of a wireless network uses a URLLC service.

In accordance with one aspect of the disclosure, a method for operating a session management function (SMF) in a computer network system is provided. The method includes receiving a request message for establishing a protocol data unit (PDU) session, deciding to perform a redundant transmission associated with a PDU session between a user plane function (UPF) and a radio access network (RAN) node, transmitting, to the UPF, a session establishment request message, receiving, from the UPF, a session establishment response message, transmitting, to the RAN node, at least two core network (CN) tunnel information for the redundant transmission, receiving, from the RAN node, at least two access network (AN) tunnel information for the redundant transmission and transmitting, to the UPF, the at least two AN tunnel information.

In accordance with another aspect of the disclosure, a method for operating a UPF in a communication system is provided. The method includes receiving, from a session management function (SMF), a session establishment request message for a redundant transmission associated with a protocol data unit (PDU) session between the UPF and a radio access network (RAN) node, transmitting, to the SMF, a session establishment response message, receiving, from the SMF, at least two access network (AN) tunnel information, allocated by the RAN node, for the redundant transmission, wherein at least two core network (CN) tunnel information are provided to the RAN node for the redundant transmission.

In accordance with yet another aspect of the disclosure, a method for operating a RAN node in a communication system is provided. The method includes transmitting, to a session management function (SMF), a request message for establishing a protocol data unit (PDU) session, receiving, from the SMF, at least two core network (CN) tunnel information for a redundant transmission associated with a protocol data unit (PDU) session between a user plane function (UPF) and the RAN node and transmitting, to the SMF, at least two access network (AN) tunnel information for the redundant transmission, wherein the at least two AN tunnel information are transferred to the UPF.

In accordance with yet another aspect of the disclosure, an SMF is provided. The SMF includes a transceiver and a controller coupled with the transceiver and configured to receive a request message for establishing a protocol data unit (PDU) session, to decide to perform a redundant transmission associated with a PDU session between a user plane function (UPF) and a radio access network (RAN) node, to transmit, to the UPF, a session establishment request message, to receive, from the UPF, a session establishment response message, to transmit, to the RAN node, at least two core network (CN) tunnel information for the redundant transmission, to receive, from the RAN node, at least two access network (AN) tunnel information for the redundant transmission, and transmit, to the UPF, the at least two AN tunnel information.

In accordance with yet another aspect of the disclosure, a UPF is provided. The UPF includes a transceiver; and a controller coupled with the transceiver and configured to receive, from a session management function (SMF), a session establishment request message for a redundant transmission associated with a protocol data unit (PDU) session between the UPF and a radio access network (RAN) node, to transmit, to the SMF, a session establishment response message, to receive, from the SMF, at least two access network (AN) tunnel information, allocated by the RAN node, for the redundant transmission, wherein at least two core network (CN) tunnel information are provided to the RAN node for the redundant transmission.

In accordance with yet another aspect of the disclosure, a RAN node is provided. The RAN node includes a transceiver and a controller coupled with the transceiver and configured to transmit, to a session management function (SMF), a request message for establishing a protocol data unit (PDU) session, to receive, from the SMF, at least two core network (CN) tunnel information for a redundant transmission associated with a protocol data unit (PDU) session between a user plane function (UPF) and the RAN node, and to transmit, to the SMF, at least two access network (AN) tunnel information for the redundant transmission, wherein the at least two AN tunnel information are transferred to the UPF.

The embodiments according to the disclosure provides efficient communication methods. In addition, the embodiments provide communication methods for reliable services in 5G communication systems. In addition, the embodiments provides redundant transmission methods.

DETAILED DESCRIPTION

Hereinafter, an embodiment of the disclosure will be described in detail with reference to the accompanying drawings. In the following description of the disclosure, a detailed description of known functions or configurations incorporated herein will be omitted when it may make the subject matter of the disclosure rather unclear. The terms which will be described below are terms defined in consideration of the functions in the disclosure, and may be different according to users, intentions of the users, or customs. Therefore, the terms should be defined on the basis of the contents throughout the specification.

Hereinafter, a base station is an entity for performing resource allocation of a terminal, and may be at least one of eNode B, Node B, a base station (BS), a next-generation radio access network (NG RAN), a radio access unit, a base station controller, or a node in the network. A terminal may include user equipment (UE), next-generation UE (NG UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing communication functions. Although the embodiment of the disclosure will be described below on the basis of an example of a 5G system, the embodiment of the disclosure may also be applied to other communication systems with similar technical backgrounds. In addition, the embodiment of the disclosure may be modified in part by those skilled in the art without departing from the scope of the disclosure, and may be applied to other communication systems.

FIG.1illustrates exemplary transmissions through a plurality of transmission paths according to an embodiment of the disclosure. This may be applied to the case where a network operator deploys a plurality of paths for reliable transmission between a RAN and a user plane function (UPF). It may be defined as a redundant transmission. In this case, if the UE transmits a packet data unit (PDU) session establishment request message, a session management function (SMF) determines to produce a PDU Session for a URLLC service and establishes a plurality of N3 tunnels between the RAN and the UPF for reliable transmission. To this end, the RAN transmits, to a core network (CN), two pieces of AN Tunnel Info including an IP address and a TEID. That is, the RAN transmits two IP addresses and two tunnel endpoint identifiers (TEIDs) of the RAN. The CN also transmits, to the RAN, two pieces of CN Tunnel Info including an IP address and a TEID. As a result, two N3 tunnels are established between the RAN and the UPF. In this case, the RAN becomes a traffic distributor for an uplink (UL), and the UPF becomes a traffic distributor for a downlink (DL). The traffic distributor for the DL must transmit the data received from a data network (DN) twice through two paths R1and R2. In this case, in order for a receiving entity to distinguish between the two received packets, a transmitting entity must transmit the packets with the same GPRS tunneling protocol-user plane (GTP-U) sequence number. The receiving entity receives data from two tunnels associated with a single PDU session ID, transmits the GTP-U packet that is received first to the UE/DN, and drops the received data with the same GTP-U sequence number.

FIG.2illustrates an exemplary message flowchart for configuring a path for ultra-reliable transmission when producing a PDU session according to an embodiment of the disclosure. The UE transmits a PDU session establishment request in operation201. If the SMF that received the same determines that the PDU session requested by the UE is intended for a URLLC service, the SMF determines to configure a plurality of transmission paths in operation202.FIG.2illustrates the case in which the CN Tunnel Info is allocated from the UPE If the SMF determines a PDU session anchor (PSA), it transmits an N4 session establishment request message to the corresponding UPF in operation203. At this time, an indication to inform that the traffic distributor is intended for URLLC path configuration is transmitted together with the same. The UPF that received the traffic distributor indication allocates two pieces of tunnel information (e.g., CN Tunnel Info1and CN Tunnel Info2) and transmits the same to the SMF through an N4 session establishment response message in operation204. The SMF transmits CN tunnel information to the RAN using an N2 SM information message in operation205. In this case, the SMF also transmits traffic distributor indication to the RAN. The RAN that received the indication produces two pieces of AN tunnel information (AN Tunnel info1and AN Tunnel info2) and transmits the same to the SMF in operation206. The SMF transmits the same to the UPF in operation207.

FIG.3illustrates a message flowchart for configuring a plurality of transmission paths and shows the case where CN Tunnel Info is configured by the SMF according to an embodiment. The embodiment ofFIG.3is the same as that ofFIG.2, except that CN Tunnel Info is allocated by the SMF. Therefore, the specific operations inFIG.3may refer to the description ofFIG.2.

FIG.4illustrates transmission through a plurality of transmission paths using an intermediate UPF (I-UPF) according to an embodiment. This is applied to the case where the network operator does not deploy a plurality of paths for reliable transmission between the RAN and the UPF. In this case, the UE transmits a PDU session establishment request message. If the session management function (SMF) determines to produce a PDU session for a URLLC service, it establishes multiple tunnels N3 and N9 between the RAN and the UPF for reliable transmission. To this end, the RAN transmits two pieces of AN Tunnel Info including an IP address and a TEID to the core network (CN). That is, the RAN transmits two IP addresses and two TEIDs of the RAN. The PSA UPF also produces two pieces of CN Tunnel Info including an IP address and a TEID. Two pieces of tunnel information produced in the RAN and the PSA UPF are allocated to I-UPF1and I-UPF2, respectively, and thus two tunnels N3 and N9 are established between the RAN and the UPF. In this case, the RAN becomes a traffic distributor for the uplink (UL), and the UPF becomes a traffic distributor for the downlink (DL). The traffic distributor for the DL must transmit the data received from the data network (DN) twice through two paths I-UPF1and I-UPF2. In this case, in order for the receiving entity to distinguish between the two received packets, the transmitting entity must transmit the packets with the same GPRS tunneling protocol-user plane (GTP-U) sequence number. The I-UPF must produce a GTP-U packet using the received GTP-U sequence number as it is, and must retransmit the same to the traffic distributor. The final receiving entity receives the data from two tunnels associated with a single PDU session ID, transmits the GTP-U packet that is received first to the UE/DN, and drops the received data with the same GTP-U sequence number. The above operation may be applied to the data for the UL as well.

FIG.5illustrates an exemplary message flowchart for configuring a path for ultra-reliable transmission when producing a PDU session according to an embodiment of the disclosure. The UE transmits a PDU session establishment request in operation501. If the SMF that received the same determines that the PDU session requested by the UE is intended for a URLLC service, the SMF determines to configure a plurality of transmission paths in operation502.FIG.5illustrates the case in which the CN Tunnel Info is allocated by the UPF. If the SMF determines a PDU session anchor (PSA), it transmits an N4 session establishment request message to the corresponding UPF in operation503. At this time, an indication to inform that the traffic distributor is intended for URLLC path configuration is transmitted together with the same. The UPF that received the traffic distributor indication allocates two pieces of tunnel information (e.g., CN Tunnel Info1and CN Tunnel Info2), and transmits the same to the SMF through an N4 session establishment response message in operation504. If the SMF determines I-UPF1and I-UPF2, it transmits an N4 session establishment request message to the corresponding UPF, respectively in operation505and operation507. The I-UPF allocates tunnel information (e.g., CN Tunnel Info_I-UPF) and transmits the same to the SMF through an N4 session establishment response message in operation506and operation508. The SMF transmits CN tunnel information of the I-UPF1and the I-UPF2to the RAN using an N2 SM information message in operation509. At this time, a traffic distributor indication is also transmitted to the RAN. The RAN that received the indication produces two pieces of AN Tunnel information (e.g., AN Tunnel info1and AN Tunnel info2) and transmits the same to the SMF in operation510. The SMF transmits, to the PSA UPF, CN tunnel information of the I-UPF1and the I-UPF2for the DL through an N4 session modification request message in operation511, and transmits, to the I-UPF1and the I-UPF2, the AN tunnel information for the DL and CN tunnel_PSA information for the UL in operation512and operation513.

FIG.6illustrates a message flowchart for configuring a plurality of transmission paths using an I-UPF and shows the case where CN Tunnel Info is configured by the SMF according to an embodiment. The embodiment ofFIG.6is the same as that ofFIG.5, except that CN Tunnel Info is allocated by the SMF. Therefore, the specific operations inFIG.6may refer to the embodiment inFIG.5.

According to the embodiment, in the embodiment of configuring simple multiple transmission paths and the embodiment of configuring multiple transmission paths using the I-UPF, it is also possible to configure a primary path and a secondary path according to the network configuration, to transmit data through one path first, and if a problem occurs in the path, to transmit the data through the other path, instead of simultaneously transmitting the data through both paths. To this end, in the case of the simple multiple transmission paths, a primary path and a secondary path must be configured when the respective traffic distributors configure the tunnel information, and a primary path and a secondary path must be configured in the I-UPF when using the I-UPF. Further, a change for the configuration of the primary path and the secondary path may also be applied to the message flowchart.

FIG.7illustrates the high-level configuration of a user equipment according to an embodiment.

Referring toFIG.7, the UE may include a transceiver710, a controller720, and a storage unit730. In the embodiment, the controller720may include circuits, application-specific integrated circuits, software, firm ware, and/or at least one processor.

The transceiver710may transmit/receive signals to/from other network entities. The controller720may control overall operations of the UE according to the embodiment proposed in the disclosure. The storage unit730may store at least one piece of information transmitted/received through the transceiver710and information produced through the controller720.

FIG.8illustrates the high-level configuration of a base station according to an embodiment of the disclosure. The base station may correspond to the RAN node in the respective embodiments.

Referring toFIG.8, the base station may include a transceiver810, a controller820, and a storage unit830. In the embodiment, the controller820may include circuits, application-specific integrated circuits, software, firm ware, and/or at least one processor.

The transceiver810may transmit/receive signals to/from other network entities. The controller820may control overall operations of the base station according to the embodiment proposed in the disclosure. The storage unit830may store at least one piece of information transmitted/received through the transceiver810and information produced through the controller820.

FIG.9illustrates a high-level configuration of higher nodes or network entities according to an embodiment of the disclosure. The higher nodes may be at least one of the AMF, the SMF, the I-UPF, the UPF, and the DN according to the respective embodiments. That is, the device configuration inFIG.9may be applied to the configuration of network entities, such as the AMF, the SMF, the I-UPF, the UPF, and the DN.

Referring toFIG.9, the higher nodes may include a transceiver910, a controller920, and a storage unit930. In the embodiment, the controller920may include circuits, application-specific integrated circuits, software, firm ware, and/or at least one processor.

The transceiver910may transmit/receive signals to/from other network entities. The controller920may control overall operations of the higher node according to the embodiment proposed in the disclosure. The storage unit930may store at least one piece of information transmitted/received through the transceiver910and information produced through the controller920.

The embodiments disclosed in the specifications and drawings are provided merely to readily describe and to help a thorough understanding of the disclosure but are not intended to limit the scope of the disclosure. Therefore, it should be construed that, in addition to the embodiments disclosed herein, all modifications and changes or modified and changed forms derived from the technical idea of the disclosure fall within the scope of the disclosure.