Apparatus and method for service subscription via an E2 interface in a wireless access network communication system

Abstract

This disclosure relates to 4G (4G) such as LTE (Long Term Evolution). th 5G (5th Generation) communication systems to support higher data transmission rates th According to various embodiments of the present disclosure, a method performed by an E2 node includes receiving a RIC subscription request message from a RIC (radio access network intelligent controller (RAN)) via an E2 interface, the RIC subscription request message including information indicating a network interface type.

Description

Technical Field

[0001] The present disclosure generally relates to a wireless access network communication system, and more specifically to an apparatus and method for subscribing to services for an O-RAN (Open Radio Access Network) base station using E2 messages of a wireless communication system.

Background Art

[0002] 4G (4 th generation) communication systems, efforts have been made to develop improved 5G (5 th generation) communication systems or pre-5G communication systems to meet the increasing demand for wireless data traffic. For this reason, 5G communication systems or pre-5G communication systems are referred to as communication systems beyond the 4G network or post-LTE (Long Term Evolution) systems.

[0003] To achieve high data transmission rates, the 5G communication system is considered to be implemented in the millimeter wave (mmWave) band (e.g., 60 gigahertz (60 GHz) band, etc.). To mitigate the path loss of radio waves in the millimeter wave band and increase the transmission distance of radio waves, in the 5G communication system, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, and large-scale antenna technologies have been discussed.

[0004] In addition, for the improvement of the system network, in the 5G communication system, technological developments such as advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, Device to Device communication (D2D), wireless backhaul, moving networks, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation are being carried out.

[0005] In addition, in the 5G system, FQAM (Hybrid Frequency Shift Keying and Quadrature Amplitude Modulation) and SWSC (Sliding Window Superposition Coding), which are advanced coding modulation (Advanced Coding Modulation, ACM) methods, and FBMC (Filter Bank Multi Carrier), NOMA (Non Orthogonal Multiple Access), and SCMA (Sparse Code Multiple Access), which are advanced access technologies, have been developed.

[0006] To meet the demand for wireless data traffic, the 5G system, NR (New Radio or Next Radio), has been commercialized. Similar to 4G, the 5G system provides users with high-data-rate services and is expected to offer wireless communication services with various purposes, such as the Internet of Things and services that require high reliability for specific purposes. Currently, the O-RAN (Open Radio Access Network), established by operators and equipment providers in a system mixed with 4G and 5G systems, defines new NE (Network Element) and interface specifications based on existing 3GPP (3rd Generation Partnership Project) standards and presents the O-RAN structure.

Summary of the Invention

Problems to be Solved by the Invention

[0007] Now, with the commercialization of 4th generation / 5th generation communication systems (hereinafter referred to as 4G / 5G systems, NR (new radio or next radio)), there is a growing demand for differentiated service support for users in virtualized networks. O-RAN newly defines existing 3GPP (3rd Generation Partnership Project) NE (network element), RU (radio unit), DU (distributed unit), CU-CP (central unit-control plane), CU-UP (central unit-user plane) as O-RU, O-DU, O-CU-CP, O-CU-UP respectively, and additionally standardizes near-real-time RIC (RAN intelligent controller). This disclosure relates to an E2 Subscription message in which a newly defined RIC requests services from an O-DU, O-CU-CP or O-CU-UP. Further, this disclosure relates to a method of processing the E2 Subscription message by subdividing it into UE units, group units, cell units, and network slice units. Here, it can be understood that O-RU, O-DU, O-CU-CP, and O-CU-UP are objects that constitute a RAN that can operate according to the O-RAN standard and can be referred to as E2 nodes.

[0008] To solve the above problems, this disclosure in the method of a first node of a wireless communication system includes steps of: a RIC generating and transmitting an E2 Subscription Request message; an E2 NODE receiving the E2 Subscription Request message from the RIC and setting a call processing EVENT; successfully transmitting a Subscription Request Response message to the RIC for the EVENT setting after the EVENT setting; and generating and transmitting an E2 INDICATION / REPORT message to the RIC based on the generated EVENT when a call processing EVENT that meets the set conditions occurs.

[0009] Also, the E2 Subscription Request message can be verified based on the detailed Information Element of the E2 Subscription Request transmitted from the RIC, and the Information Element information can include MESSAGE TYPE identifier information, RIC REQUEST ID identifier information, E2 NODE FUNCTION ID identifier information, and RIC SUBSCRIPTION TYPE identifier information set based on the call processing function of the E2 NODE.

[0010] Also, the E2 Subscription Response message can be verified based on the detailed Information Element of the E2 Subscription Response transmitted from the RIC, and the Information Element information can include MESSAGE TYPE identifier information, RIC REQUEST ID identifier information, E2 NODE FUNCTION ID identifier information, and RIC SUBSCRIPTION RESULT identifier information set based on the call processing function of the E2 node.

Means for Solving the Problems

[0011] According to various embodiments of the present disclosure, the method performed by the E2 node includes the process of receiving an RIC (RAN (radio access network) intelligent controller) subscription request message from the RIC via the E2 interface, and the RIC subscription request message can include information indicating the network interface type.

[0012] According to various embodiments of the present disclosure, a method performed by a RIC (RAN (radio access network) intelligent controller) includes a process of transmitting a RIC subscription request message to an E2 node via an E2 interface, and the RIC subscription request message may include information indicating a network interface type.

[0013] According to various embodiments of the present disclosure, a device functioning as an E2 node includes at least one transceiver and at least one processor coupled to the at least one transceiver, and the at least one processor is configured to receive a RIC (RAN (radio access network) intelligent controller) subscription request message from the RIC via an E2 interface, and the RIC subscription request message may include information indicating a network interface type.

[0014] According to various embodiments of the present disclosure, a device functioning as a RIC (RAN (radio access network) intelligent controller) includes at least one transceiver and at least one processor coupled to the at least one transceiver, and the at least one processor is configured to transmit a RIC subscription request message to an E2 node via an E2 interface, and the RIC subscription request message may include information indicating a network interface type.

Effects of the Invention

[0015] Apparatuses and methods according to various embodiments of the present disclosure enable an effective subscription procedure between a near RT RIC (RAN intelligent controller) and an E2 node by indicating the type of network interface in a subscription request that requests subscription to the RAN (radio access network) function of the E2 node. The effects obtained by the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those of ordinary skill in the technical field to which the present disclosure pertains from the following description.

Brief Description of the Drawings

[0016]

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DETAILED DESCRIPTION OF THE INVENTION

[0017] The terms used in this disclosure are merely used to describe specific embodiments and are not intended to limit the scope of other embodiments. Singular expressions can include plural expressions unless the context clearly indicates a different meaning. Terms used herein, including technical or scientific terms, can have the same meaning as commonly understood by those of ordinary skill in the technical field described in this disclosure. Among the terms used in this disclosure, terms defined in a general dictionary can be interpreted as having the same or similar meaning as their meaning in the context of the related art, and are not interpreted as having an ideal or overly formal meaning unless clearly defined in this disclosure. In some cases, even terms defined in this disclosure cannot be interpreted so as to exclude embodiments of this disclosure.

[0018] In various embodiments of the disclosure described below, a hardware approach is illustrated as an example. However, since various embodiments of the disclosure include techniques that use both hardware and software, various embodiments of the disclosure do not exclude software-based approaches.

[0019] The following disclosure relates to an apparatus and method for performing a subscription procedure between an apparatus in a radio access network (RAN) and an apparatus controlling the RAN in a wireless communication system.

[0020] Terms referring to signals, terms referring to channels, terms referring to control information, terms referring to network entities, terms referring to components of an apparatus, etc., used in the following description are exemplified for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0021] Note that although the present disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project)), this is merely for illustrative purposes. The various embodiments of the present disclosure can be easily modified and applied in other communication systems.

[0022] Hereinafter, in the present disclosure, the uplink means a radio link through which a terminal (User Equipment, UE or Mobile Station, MS) transmits data or a control signal to a base station (eNode B, or base station, BS), and the downlink means a radio link through which the base station transmits data or a control signal to the terminal. Also, the base station is the entity that performs resource allocation for the terminal and can be at least one of eNode B, Node B, BS (Base station), gNB (generation Node B) radio connection unit, base station controller, or a node on the network. The terminal can include UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions.

[0023] To meet the demand for wireless data traffic, the fifth-generation communication system (hereinafter, may also be mixedly referred to as 5G system, NR (new radio or next radio) system, etc.) has been commercialized, and like 4G, the 5G system provides users with high data transmission rate services, and it is expected that various wireless communication services with diverse purposes such as the Internet of Things and services that require high reliability for specific purposes can be provided.

[0024] Currently, in a system mixed with 4G communication systems, 5G systems, etc., the O-RAN (Open Radio Access Network) established by operators and equipment providers defines new NE (Network Element) and interface specifications based on existing 3GPP standards, leading to the emergence of the O-RAN architecture. O-RAN newly defines the existing 3GPP NEs, RU (Radio Unit), DU (Distributed Unit), CU (Central Unit)-CP (Control Plane), and CU-UP (User Plane) as O-RU, O-DU, O-CU-CP, and O-CU-UP respectively. Additionally, O-RAN standardized the near-real-time RIC (RAN Intelligent Controller) and non-real-time (NRT) RIC. As an example, the RIC can be a server centrally located in one physical location. Also, the RIC is a logical node that can collect information at the cell site where the terminal communicates with the O-DU, O-CU-CP, or O-CU-UP. The connection between the O-DU and the RIC, the O-CU-CP and the RIC, and the O-CU-UP and the RIC can be through Ethernet. Therefore, interface specifications for communication between the O-DU and the RIC, the O-CU-CP and the RIC, and the O-CU-UP and the RIC are required, and message specifications such as E2-DU, E2-CU-CP, and E2-CU-UP are needed to define the procedures between the O-DU, O-CU-CP, O-CU-UP, and the RIC. In particular, differentiated service support for users in a virtualized network is required, and by concentrating the call processing messages / functions generated in the O-RAN in the RIC, the functional definitions of the messages of E2-DU, E2-CU-CP, and E2-CU-UP are necessary to support services for a wide range of cell coverage.

[0025] Specifically, the RIC can set event occurrence conditions by generating and sending an E2 subscription message to the O-DU, O-CU-CP, or O-CU-UP. The O-DU, O-CU-CP, or O-CU-UP determines whether the set conditions are met, and if the conditions are met, the 3GPP call processing message is placed in a container for the RIC, classified by user identifier, cell identifier, and network slice identifier, and then can be sent by E2 indication / report.

[0026] The call processing message information collected in the O-RAN based on the user identifier can be identified by the RIC as being for a specific user / specific cell / specific network slice for each interface. The collected information can be transmitted from at least one of the (O-)CU-CP, (O-)CU-UP, and (O-)DU. The RIC confirms that the information collected from different entities based on the user identifier is for a specific user / specific cell / specific network slice, and based on the collected information, can provide services specialized for a specific user / specific cell / specific network slice for multiple cells / network slices, and can also determine the key performance indicator (KPI) of the services provided to each user.

[0027] Since general call processing services are limited to base stations, the number of supported cells is restricted. Also, because the collected information is limited to specific base stations, efficient monitoring of radio resources across the board was not possible. According to various embodiments of the present disclosure, the RIC collects each I / F-specific or each call processing message (e.g., E1, F1, X2, XN, RRC, etc.) generated by the O-RU, O-DU, O-CU-CP, or O-CU-UP, thereby enabling efficient resource optimization and user-specialized services or user-requested services for a wide range of cells for a specific user / specific cell / specific network slice. For example, the RIC can efficiently divide network slices or set additional carriers so that a specific terminal can receive services through carrier aggregation, or set additional cells for dual connectivity so that a specific terminal can receive services through dual connectivity (DC). Also, the RIC can be set so that a specific terminal avoids connecting to a specific cell and connects to a specific cell when moving between cells. Further, the RIC can efficiently perform resource optimization by machine learning through analysis based on the collected information. Note that the resource optimization of the present disclosure is not limited to the described content. Furthermore, according to the present disclosure, it is possible to collect information not only by terminal but also by bearer and analyze it.

[0028] The information collected for a specific user can be used by a collection server or RIC (near RIC) or NRT-RIC, but can also be provided to the OSS (operations support system) or / and BSS (business support system) and used to provide user-specialized services.

[0029] Figure 1 shows an example of a 4G (4th generation) LTE (Long Term Evolution) core system.

[0030] Referring to FIG. 1, the LTE core system includes a base station 110, a terminal 120, an S-GW (serving gateway) 130, a P-GW (packet data network gateway) 140, an MME (mobility management entity) 150, an HSS (home subscriber server) 160, and a PCRF (policy and charging rule function) 170.

[0031] The base station 110 is a network infrastructure that provides a wireless connection to the terminal 120. For example, the base station 110 is a device that collectively schedules state information such as the buffer state, available transmission power, and channel state of the terminal 110. The base station 110 has a coverage defined in a predetermined geographical area based on the distance at which it can transmit signals. The base station 110 is connected to the MME 150 via an S1-MME interface. In addition to the base station, the base station 110 can also be referred to by other terms having the same technical meaning, such as "access point (AP)", "eNodeB (eNB)", "wireless point", "transmission / reception point (TRP)".

[0032] The terminal 120 is a device used by a user and communicates with the base station 110 via a wireless channel. In some cases, the terminal 120 can be operated without user involvement. That is, at least one of the terminal 120 and the terminal 130 is a device that performs machine type communication (MTC) and may not be carried by a user. The terminal 120 can also be referred to by other terms such as "user equipment (UE)", "mobile station", "subscriber station", "customer-premises equipment (CPE)", "remote terminal", "wireless terminal", or "user device" or other terms with an equivalent technical meaning in addition to "terminal".

[0033] The S-GW 130 provides a data bearer and generates or controls the data bearer according to the control of the MME 150. For example, the S-GW 130 processes the packets arriving from the base station 110 or the packets to be forwarded to the base station 110. Also, the S-GW 130 can play the role of anchoring during the handover between the base stations of the terminal 120. The P-GW 140 can function as a connection point to an external network (e.g., the Internet network). Also, the P-GW 140 assigns an IP (Internet Protocol) address to the terminal 120 and plays the role of an anchor for the S-GW 130. Also, the P-GW 140 can apply the QoS (Quality of Service) policy of the terminal 120 and manage the account data.

[0034] The MME 150 manages the mobility of the terminal 120. Also, the MME 150 can perform authentication for the terminal 120, bearer management, etc. That is, the MME 150 is responsible for mobility management and various control functions for the terminal. The MME 150 can operate in conjunction with an SGSN (serving GPRS support node).

[0035] The HSS 160 stores key information for authenticating the terminal 120 and subscriber profiles. The key information and subscriber profiles are transmitted from the HSS 160 to the MME 150 when the terminal 120 connects to the network.

[0036] The PCRF 170 defines rules for policy and charging. The stored information is transmitted from the PCRF 180 to the P-GW 140, and the P-GW 140 can perform control (e.g., QoS management, charging, etc.) for the terminal 120 based on the information provided by the PCRF 180.

[0037] Carrier aggregation (hereinafter referred to as "CA") technology combines multiple component carriers so that a single terminal can use such multiple component carriers to simultaneously transmit and receive signals, thereby increasing the frequency utilization efficiency from the perspective of the terminal or the base station. Specifically, according to CA technology, the terminal and the base station can use multiple component carriers in the uplink (UL) and downlink (DL) respectively to transmit and receive signals using a wide bandwidth. At this time, each component carrier is located in a different frequency band. Hereinafter, the uplink means a communication link through which the terminal transmits a signal to the base station, and the downlink means a communication link through which the base station transmits a signal to the terminal. At this time, the number of uplink component carriers and downlink component carriers may be different.

[0038] Dual / multi-connectivity technology (dual connectivity or multi connectivity) is a technology that increases the frequency usage efficiency from the perspective of a terminal or a base station by enabling a single terminal to connect to multiple different base stations and simultaneously use carriers in each of the multiple base stations located in different frequency bands to transmit and receive signals. The terminal can be simultaneously connected to a first base station (e.g., a base station providing services using LTE technology or 4G mobile communication technology) and a second base station (e.g., a base station providing services using NR (new radio) technology or 5G (5th generation) mobile communication technology) to transmit and receive traffic. At this time, the frequency resources used by each base station may be located in different bands. In this way, the operation mode based on the LTE-NR dual-connectivity method can be referred to as 5G NSA (non-standalone).

[0039] Figure 2A shows an example of a 5G NSA system.

[0040] Referring to Figure 2A, the 5G NSA system includes an NR RAN 210a, an LTE RAN 210b, a terminal 220, and an EPC 250. The NR RAN 210a and the LTE RAN 210b are connected to the EPC 150, and the terminal 220 can simultaneously receive services from either one or both of the NR RAN 210a and the LTE RAN 210b. The NR RAN 210a includes at least one NR base station, and the LTE RAN 210b includes at least one LTE base station. Here, the NR base station can be referred to as a "5G node (5th generation Node)", a "gNodeB (next generation NodeB)", or other terms having an equivalent technical meaning. In addition, the NR base station can have a structure separated into a CU (central unit) and a DU (digital unit), and the CU can have a structure separated into a CU-CP (control plane) unit and a CU-UP (user plane) unit.

[0041] With the structure as shown in FIG. 2, the terminal 220 can establish an RRC (radio resource control) connection via a first base station (e.g., a base station belonging to LTE RAN210b) and be served with functions provided in the control plane (e.g., connection management, mobility management, etc.). Also, the terminal 220 can be provided with additional radio resources for transmitting and receiving data via a second base station (e.g., a base station belonging to NR RAN210a). Such a dual connectivity technology using LTE and NR can be referred to as EN-DC (E-UTRA (evolved universal terrestrial radio access) - NR dual connectivity). Similarly, a dual connectivity technology where the first base station uses NR technology and the second base station uses LTE technology is referred to as NE-DC (NR - E-UTRA dual connectivity). Also, various embodiments can be applied to other various forms of multi-connectivity and carrier aggregation technologies. Further, various embodiments can also be applied when a first system using a first communication technology and a second system using a second communication technology are implemented in one device or when a first base station and a second base station are located at the same geographical location.

[0042] FIG. 2B shows an example of an architecture for O-RAN. For the purpose of E2-SM-KPIMON (KPI (key performance indicator) monitoring) of the E2 service model, while the O-RAN non-standalone mode within the multi-connectivity operation using E-UTRA and NR radio access technologies is considered, the E2 node can be assumed to be in the O-RAN stand-alone mode.

[0043] Referring to FIG. 2B, in the deployment of the O-RAN non-standalone mode, the eNB is connected to the EPC via the S1-C / S1-U interfaces and to the O-CU-CP via the X2 interface. The O-CU-CP for the deployment of the O-RAN standalone mode can be connected to the 5GC (5G core) via the N2 / N3 interfaces.

[0044] FIG. 3 shows the protocol stack of the E2 application protocol messages in a radio access network according to various embodiments of the present disclosure. Referring to FIG. 3, the control plane includes a transport network layer and a radio network layer. The transport network layer includes a physical layer 310, a data link layer 320, an IP (Internet Protocol) 330, and an SCTP (stream control transmission protocol) 340.

[0045] The radio network layer includes an E2AP 350. The E2AP 350 is used to transmit subscription messages, indication messages, control messages, service update messages, and service query messages, and is transmitted at a higher layer of the SCTP 340 and the IP 330.

[0046] FIG. 4 shows an example of the connection between a base station and a RIC (radio access network intelligence controller) in a radio access network according to various embodiments of the present disclosure.

[0047] Referring to FIG. 4, RIC 440 is connected to O-CU-CP 420, O-CU-UP 410, and O-DU 430. RIC 440 is responsible for the function to control the RAN node (or the device performing the RAN function, e.g., O-CU-CP 420, O-CU-UP 410, O-DU 430). RIC 440 can be defined as a device for customizing the RAN functionality for new services or regional resource optimization. RIC 440 can provide functions such as network intelligence (e.g., policy enforcement, handover optimization), resource assurance (e.g., radio-link management, advanced self-organized-network), resource control (e.g., load balancing, slicing policy). RIC 440 can communicate with O-CU-CP 420, O-CU-UP 410, and O-DU 430. RIC 440 can be connected to each node through the E2-CP, E2-UP, and E2-DU interfaces. Also, the interfaces between O-CU-CP and DU, and between O-CU-UP and DU can be referred to as the F1 interface. In the following description, DU and O-DU, CU-CP and O-CU-CP, CU-UP and O-CU-UP can be used interchangeably.

[0048] FIG. 4 illustrates one RIC 440, but according to various embodiments, there may be multiple RICs. The multiple RICs can be implemented in multiple hardwares located at the same physical location, or can be implemented by virtualization using one hardware.

[0049] FIG. 5 shows the configuration of the apparatus according to various embodiments of the present disclosure. The structure illustrated in FIG. 5 can be understood as the configuration of an apparatus having at least one function among the RIC, O-CU-CP, O-CU-UP, and O-DU in FIG. 5. Terms such as “… unit” and “… device” used hereinafter mean a unit that processes at least one function or operation, which can be implemented by hardware, software, or a combination of hardware and software.

[0050] Referring to FIG. 5 above, the core network apparatus includes a communication unit 510, a storage unit 520, and a control unit 530.

[0051] The communication unit 510 provides an interface for communicating with other devices in the network. That is, the communication unit 510 converts a bit string transmitted from the core network apparatus to other devices into a physical signal, and converts a physical signal received from other devices into a bit string. That is, the communication unit 510 can transmit and receive signals. Therefore, the communication unit 510 can be referred to as a modem, a transmitter, a receiver, or a transceiver. At this time, the communication unit 510 enables the core network apparatus to communicate with other devices or systems via a backhaul connection (e.g., a wired backhaul or a wireless backhaul) or via the network.

[0052] The storage unit 520 stores data such as a basic program, an application program, and setting information for the operation of the core network apparatus. The storage unit 520 can be composed of a volatile memory, a non-volatile memory, or a combination of a volatile memory and a non-volatile memory. And the storage unit 520 provides the stored data in response to a request from the control unit 530.

[0053] The control unit 530 controls the overall operation of the core network device. For example, the control unit 530 transmits and receives signals through the communication unit 510. Also, the control unit 530 records and reads data in the storage unit 520. For this purpose, the control unit 530 can include at least one processor. According to various embodiments, the control unit 530 can control the device to operate according to the various embodiments described in the present disclosure.

[0054] FIG. 6 shows the logical functions associated with the E2 messages of the E2 node and the RIC in a radio access network according to various embodiments of the present disclosure.

[0055] Referring to FIG. 6, the RIC 640 and the E2 node 610 can transmit or receive E2 messages to and from each other. For example, the E2 node 610 can be an O-CU-CP, O-CU-UP, O-DU, or a base station. The communication interface of the E2 node can be determined by the type of the E2 node 610. For example, the E2 node 610 can communicate with other E2 nodes 616 via an E1 interface or an F1 interface. Or, for example, the E2 node 610 can communicate with the E2 node 616 via an X2 interface or an XN interface. Or, for example, the E2 node 610 can communicate via an S1 interface or an NGAP (next generation application protocol) interface (i.e., the interface between an NG (next generation) RAN node and the AMF).

[0056] The E2 node 610 can include an E2 node function 612. The E2 node function 612 is a function corresponding to a specific xApp (application S / W) 646 installed in the RIC 640. For example, in the case of a KPI monitor, KPI monitor collection software is installed in the RIC 640, and after the E2 node 610 generates KPI parameters, the E2 node 610 can include an E2 node function 612 that transmits an E2 message including the KPI parameters to the E2 termination 642 located in the RIC 640. The E2 node 610 can include an RRM (radio resource management) 614. The E2 node 610 can manage resources provided to the radio network for the terminal.

[0057] The E2 termination 642 located in the RIC 640 is the termination of the RIC 640 for the E2 message, and after analyzing the E2 message transmitted by the E2 node 610, it performs the function of transmitting it to the xApp 646. The DB (database) 644 located in the RIC 640 can be used for the E2 termination 624 or the xApp 616. The E2 node 610 shown in FIG. 6 is the termination of at least one interface and can be understood as the termination of the message transmitted to the terminal, the surrounding base station, and the core network.

[0058] FIG. 7A shows an example of a signaling procedure between the E2 node and the RIC (RAN (radio access network) intelligent controller). Specifically, FIG. 7A shows the Setup procedure of the E2 I / F between the E2 node and the RIC and the RIC subscription message transmission procedure. The E2 node 610 is exemplified as the E2 node, and the RIC 640 is exemplified as the RIC.

[0059] Referring to FIG. 7A, at step (701), the E2 node can transmit an E2 setup request message to the RIC. The E2 NODE FUNCTION function located in the E2 node searches for the RIC using the RIC IP address (Address) set by OAM and transmits an E2 SETUP REQUEST message. The E2 SETUP REQUEST message includes a RAN Function Definition that defines the functions of the RAN supported by the E2 node, E2 NODE ID information, and the like. The RAN Function Definition value is a value set by OAM, and the RIC receives information regarding the OAM-set value, enabling the RIC to determine which call processing functions the E2 node supports based on the RAN Function Definition value. At step (703), the RIC can receive an E2 setup response message from the E2 node. If the RIC can accept the E2 SETUP REQUEST message transmitted by the E2 node, it transmits an E2 SETUP RESPONSE message.

[0060] At step (705), the RIC can transmit a subscription request message to the E2 node. A specific xApp located in the RIC requests a subscription to a specific RAN Function Definition function supported by the E2 for the RIC E2 Termination function. Here, according to one embodiment, the subscription request message in step (705) may be included in the E2 SETUP RESPONSE message in step (703) and transmitted together. For example, the RAN function can include functions of X2AP, F1AP, E1AP, S1AP, NGAP interfaces or / and internal RAN functions for controlling UEs or cells.

[0061] In step (707), the E2 node can transmit an access request response to the RIC. The E2 Node Function of the E2 node decodes the Subscription Request Message, and after successfully setting the event condition requested by the RIC for the E2 Node Function, it communicates to the RIC that the event trigger condition has been successfully set in the Subscription Response.

[0062] In step (709), the E2 node can transmit an E2 RIC indication message to the RIC. When a specific event condition occurs, the E2 node transmits an E2 RIC Indication message to the RIC.

[0063] In step (711), the E2 node can transmit a service update message to the RIC. When a change occurs in the E2 NODE function capability Information Element (E2 NODECapa), the E2 node sends the changed E2 NODECapa in the E2 SERVICE UPDATE to the RIC.

[0064] In FIG. 7A, the SETUP procedure, RIC subscription procedure, RIC Indication procedure, and update message transmission procedure are described in sequence. However, various embodiments of the present disclosure are not limited to the above order and procedures. That is, in some embodiments, the E2 node and the RIC can independently perform the E2 setup procedure from step (701) to step (703). In some embodiments, the E2 node and the RIC can independently perform the subscription procedure from step (709) to step (707). On the other hand, according to another embodiment, as described above, the E2 setup response message can also include a subscription request message. In some embodiments, the E2 node and the RIC can independently perform the RIC indication procedure in step (709). Also, in some embodiments, the E2 node and the RIC can independently perform the RIC indication procedure in step (709). In addition, the E2 node and the RIC can perform at least a part of the above procedures together or individually.

[0065] FIG. 7B shows an example of a subscription procedure between an E2 node and a RIC. The E2 node 610 is exemplified as the E2 node, and the RIC 640 is exemplified as the RIC.

[0066] Referring to FIG. 7B, at step (751), the RIC can request to subscribe to the E2 termination. For example, the E2 Relay xApp located in the RIC can request a subscription to the NGAP I / F for the E2 Relay message function and the Initial UE message for the RIC E2 Termination function.

[0067] At step (753), the RIC can transmit a RIC subscription request to the E2 node. For example, the RIC E2 Termination function generates an E2 Subscription Request Message from the Initial UE message Relay message for the NGAP I / F requested in step (751) and transmits it to the E2 node.

[0068] In step (755), the E2 node can transmit an RIC join response to the RIC. Specifically, when the E2 Node Function of the E2 node that has received the E2 Subscription Request Message decodes the message and an Initial UE message is generated on the NGAP I / F, after successfully setting the event condition for transmitting to the RIC by placing it in a container in the RIC indication message for each UE, each cell, or each network slice, it can communicate to the RIC that the event trigger condition has been successfully set in the subscription response (Subscription Response).

[0069] In step (757), the E2 node can transmit an RIC indication to the RIC. When an Initial UE message is generated on the NGAP I / F by the UE, the E2 node can transmit the NGAP Initial UE message in a container in the E2 RIC Indication message to the RIC.

[0070] Some of the content described in FIG. 7A may also be applied in the same or similar manner in FIG. 7B.

[0071] FIG. 8 shows the IE (Information Element) of the E2 Subscription Request Message. The first IE is the Message Type, and the Message Type has a unique value for each E2 message. The detailed content of the Message Type is shown in FIG. 9.

[0072] The second IE is the RIC REQUEST ID, which specifies a specific xApp. The detailed content of the message is shown in FIG. 10.

[0073] The third IE is the E2 NODE FUNCTION ID. The E2 NODE FUNCTION ID has range values separated by E2 node, and a specific E2 NODE FUNCTION can be specified for a specific E2 node. The detailed content of the message is shown in FIG. 11.

[0074] The fourth IE is the RIC SUBSCRIPTION TYPE, which can add various types to the E2 node and set the event trigger condition. The detailed content of the Event trigger condition type is shown in FIG. 12, and the E2 Message Relay defined in this disclosure is a type of Event trigger condition type, and the detailed content of the message is shown in FIG. 13.

[0075] FIG. 9 shows the details of the Message Type IE. The Procedure Code value, which is the first IE, is an integer value in the range of 0 to 255, and a specific MESSAGE TYPE (PROCEDURE CODE) is set. For example, the Procedure Code value 0 is set for Subscription, the Procedure Code value 1 is set for E2 SETUP, the Procedure Code value 2 is set for the Indication Request Message value, etc., from 0 to 255, that is, a total of 256 message values can be set. For example, it is defined in O-RAN as shown in the following [Table 1].

[0076]

Table 1

[0077] The second IE in the Message Type IE, the Type of message, indicates the type of the message, and Initiating, Successful, and Unsuccessful messages can be defined.

[0078] Figure 10 is the RIC REQUEST ID value. The RIC REQUEST ID value is an integer value in the range of 0 to 65535, and the value can be set uniquely for a specific xApp. Figure 11 is the E2 NODE FUNCTION ID value. The E2 NODE FUNCTION ID value is an integer value in the range of 0 to 4095, and the range values can be set separately for each E2 node.

[0079]

Table 2

[0080] Values after 2048 are Reserved values and can be set when additional E2 nodes are added.

[0081] Figure 12 is the RIC SUBSCRIPTION TYPE value. The RIC SUBSCRIPTION TYPE value is an integer value in the range of 0 to 255, and the Trigger value can be defined for a specific function of a specific E2 NODE FUNCTION of the E2 node. For example, the I / F-based message relay function can be defined as RIC SUBSCRIPTION TYPE 0.

[0082] Figure 13 is an example of a detailed message for the E2 Message Relay function proposed in this disclosure.

[0083] The first IE INTERFACE AP ID is an integer value in the range of 1 to 32, which specifies a specific I / F. For example, the LTE-RRC of the UU interface between the terminal and the LTE eNB has a set value of '0', the NR RRC of the UU interface between the 5G NR O-CU-CP and the terminal has a set value of '1', the F1 Interface is '2', the E1 Interface is '3', the X2 Interface is '4', the XN Interface is '5', the NGAP Interface is '6', and the S1 Interface is '7'. In this order, up to 32 I / F definitions are possible.

[0084] The second IE Global Node ID is an Optional IE, which is used to set whether the target base station that transmitted the X2 Message is an LTE Macro base station, a HeNB (home eNB) base station, or a 5G-NR base station when the LTE X2 or 5G-NR XN I / F message is relayed and transmitted.

[0085] The third IE is the MESSAGE PROCOL ID List, which can be divided into two types: the "All Message" IE that specifies Relay for all messages for each I / F, and the Partial Message List IE that specifies Relay only for specific messages for each I / F. The Partial Message List can specify a maximum of 256 messages, and each message can be defined with the Message ID defined in the Subscription message Information and the optional Interface direction. The Message ID is a unique value defined for each I / F of the LTE base station and 5G NR base station by 3GPP. When the 3GPP MESSAGE TYPE (PROCEDURE CODE) value can be used, the values additionally defined by O-RAN can also be used. Examples of the values defined by 3GPP are as shown in the following [Table 3].

[0086]

Table 3

[0087] The Interface direction defined in the Optional IE can be set for I / F messages that can be transmitted in both directions, such as X2 / XN, and it can be set whether the message of the I / F requesting relay to the RIC is an incoming message from another E2 node (e.g., eNB, O-CU-CP) or an outgoing message.

[0088] Figure 14 is an example of a detailed message for the E2 Relay Subscription Response function proposed in the present invention.

[0089] The first IE is MESSAGE TYPE, which has a unique value for each E2 message. The detailed content of Message Type is shown in FIG. 9.

[0090] The second IE is RIC REQUEST ID, which specifies a specific xApp. The detailed content of the message is shown in FIG. 10.

[0091] The third IE is E2 NODE FUNCTION ID. The E2 NODE FUNCTION ID has a range value for each E2 node, and a specific E2 NODE FUNCTION can be specified for a specific E2 node. The detailed content of the message is shown in FIG. 11.

[0092] The fourth IE is Subscription message Condition, which is the IE(s) for setting the Message ID that failed when the subscription procedure fails. When set to All Message, it means that the I / F set with the E2 Subscription Request Message INTERFACE AP ID is not subscribable. When set to Partial Message List, it means that the subscription is not possible, limited to the specific application protocol message set in the list of Message ID.

[0093] According to various embodiments of the present disclosure, an Event condition is set for call processing functions of an O-RU, O-DU, O-CU-CP, or O-CU-UP, that is, an E2 node, in an E2 SUBSCRIPTION message (by interface and by call processing function), and 3GPP messages for all call processing functions that occur for a specific call processing function or by interface are packaged in a Container and transmitted to the RIC. Thereby, it is possible to efficiently provide the call processing request service of the RIC.

[0094] The method according to the embodiments described in the claims or the specification of the present disclosure can be implemented in the form of hardware, software, or a combination of hardware and software.

[0095] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions for causing the electronic device to execute the method according to the embodiments described in the claims or the specification of the present disclosure.

[0096] Such programs (software modules, software) can be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc-ROMs (CD-ROMs), digital versatile discs (DVDs), or other forms of optical storage devices, magnetic cassettes. They can also be stored in a memory composed of some or all of these in combination. Also, there may be multiple of each constituent memory.

[0097] In addition, the program can be stored in an attachable storage device that can be accessed through a communication network such as the Internet, Intranet, LAN (local area network), WAN (wide area network), or SAN (storage area network), or a communication network composed of a combination thereof. Such a storage device can be connected to the device that implements the embodiments of the present disclosure through an external port. Also, a separate storage device on the communication network can be connected to the device that implements the embodiments of the present disclosure.

[0098] In the specific embodiments of the present disclosure described above, the components included in the disclosure are represented in singular or plural forms by the presented specific embodiments. However, the singular or plural forms are selected to suit the situation presented for the convenience of explanation, and the present disclosure is not limited to singular or plural components. Even components represented in plural forms may be constituted by a single component, or even components represented in singular form may be constituted by plural components.

[0099] On the other hand, although the detailed description of the present disclosure has been made with respect to specific embodiments, it goes without saying that various modifications are possible within the scope not departing from the present disclosure.

Description of Reference Numerals

[0100] 110 Base Station 120 Terminal 130 S-GW 140 P-GW 150 MME 160 HSS 170 PCRF 210a NR 210b LTE 220 Terminal 250 EPC

Claims

1. A method performed by an E2 node, comprising: receiving, via an E2 interface, a RIC (RAN (radio access network) intelligent controller) subscription request message from a RIC, wherein the RIC subscription request message includes first information indicating a network interface type, second information indicating a node ID, and third information indicating a protocol ID for the interface, and when the first information indicates an X2 interface, the node ID indicates one of an eNB (evolved NodeB) ID or an NR (new radio) base station ID.

2. The method according to claim 1, wherein the network interface type includes at least one of an F1 interface, an E1 interface, the X2 interface, an XN interface, an NG interface, or an S1 interface.

3. The RIC subscription request message includes a RAN function ID, and the method according to claim 1, wherein the RIC subscription request message is a message for subscribing to a function corresponding to the RAN function ID of the E2 node.

4. The RIC subscription request message further includes fourth information indicating an interface direction, and the method according to claim 1, wherein the interface direction includes at least one of incoming or outgoing.

5. The method according to claim 1, further comprising transmitting, to the RIC, a RIC subscription response message for accepting the RIC subscription request message.

6. The RIC is a near-real-time (near RT) RIC, The method according to claim 1, wherein the E2 node includes an O-DU (O-RAN distributed unit), an O-CU-CP (O-RAN central unit - control plane), an O-CU-UP (O-RAN central unit - user plane), or an O-eNB (O-RAN eNodeB).

7. A method performed by an RIC (RAN (radio access network) intelligent controller), including the step of transmitting an RIC subscription request message to an E2 node via an E2 interface, The RIC subscription request message includes first information indicating a network interface type, second information indicating a node ID (identifier), and third information indicating a protocol ID for the interface, and When the first information indicates an X2 interface, the node ID indicates one of an eNB (evolved NodeB) ID or an NR (new radio) base station ID.

8. The method according to claim 7, wherein the network interface type includes at least one of an F1 interface, an E1 interface, the X2 interface, an XN interface, an NG interface, or an S1 interface.

9. The RIC subscription request message includes a RAN function ID, and The method according to claim 7, wherein the RIC subscription request message is a message for subscribing to a function corresponding to the RAN function ID of the E2 node.

10. The RIC joining request message further includes fourth information indicating an interface direction, and The method according to claim 7, wherein the interface direction includes at least one of incoming or outgoing. **Claim 11** The method according to claim 7, further comprising the step of receiving an RIC joining response message for accepting the RIC joining request message. **Claim 12** The RIC is a near real-time (near RT) RIC, The method according to claim 7, wherein the E2 node includes an O-DU (O-RAN distributed unit), an O-CU-CP (O-RAN central unit - control plane), an O-CU-UP (O-RAN central unit - user plane), or an O-eNB (O-RAN eNodeB). **Claim 13** An apparatus functioning as an E2 node or an RIC (radio access network intelligent controller), At least one transceiver, and At least one processor coupled to the at least one transceiver, The at least one processor is configured to perform one of the methods according to any one of claims 1 to 12.

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