Base station and method for controlling connection to user devices

Abstract

The present disclosure relates to a base station for efficiently managing radio resource control (RRC) connections to a plurality of user equipments (UEs), and a control method therefor. The method is characterized by identifying whether the total number of UEs RRC-connected to the base station exceeds a pre-set reference number, and in response thereto, setting an RRC connection release timer to a first duration for a first group of UEs using an emergency call service, and differentially setting a second duration shorter than the first duration for a remaining second group of UEs distinguished from the first group, to thereby optimize resources.

Description

Base station and method for controlling connections to user devices

[0001] The present disclosure relates to a base station and a method for controlling connections to user devices.

[0002] A base station can establish connections with multiple user devices. The base station can provide functions to manage connections for multiple user devices. Some of the multiple user devices may disconnect from the base station and connect to another base station. Some of the multiple user devices may temporarily disconnect from the base station to reduce power consumption.

[0003] The information described above may be provided as related art for the purpose of aiding understanding of the present disclosure. No claim or determination is made as to whether any of the foregoing may be applied as prior art related to the present disclosure.

[0004] According to one embodiment, the base station may include a transceiver, a memory including instructions and one or more storage media, and at least one processor including a processing circuit. When the instructions are executed individually or collectively by the at least one processor, the base station may be caused to identify the number of user equipment (UE) devices to which a radio resource control (RRC) connection has been established, identify at least one user equipment in a first group to which an emergency call service is provided among the user equipment devices based on the number of user equipment devices exceeding a reference number, set the duration of a timer for disconnecting the RRC connection to a first duration for each of the at least one user equipment in the first group, and set the duration of a timer for disconnecting the RRC connection to a second duration shorter than the first duration for each of the at least one user equipment in a second group distinct from the first group.

[0005] According to one embodiment, a method performed by a base station may include: identifying the number of user equipment (UE) devices to which a radio resource control (RRC) connection has been established; identifying at least one user device of a first group to which an emergency call service is provided among the user devices, based on the number of user devices exceeding a reference number; setting the duration of a timer for disconnecting the RRC connection to a first duration for each of the at least one user device of the first group; and setting the duration of a timer for disconnecting the RRC connection to a second duration shorter than the first duration for each of the at least one user device of a second group distinguished from the first group.

[0006] According to one embodiment, a non-transient computer-readable storage medium may store one or more programs. The one or more programs may include instructions that, when executed by at least one processor of a base station, cause the base station to identify the number of user equipment (UE) devices to which a radio resource control (RRC) connection has been established, identify at least one user equipment in a first group to which an emergency call service is provided among the multiple user equipment devices based on the number of multiple user equipment devices exceeding a reference number, set the duration of a timer for disconnecting the RRC connection to a first duration for each of the at least one user equipment in the first group, and set the duration of a timer for disconnecting the RRC connection to a second duration shorter than the first duration for each of the at least one user equipment in a second group distinct from the first group.

[0007] Figure 1 illustrates an example of a wireless communication system.

[0008] Figure 2a illustrates the interface between an upper network node and a lower network node.

[0009] Figure 2b illustrates the fronthall interface of an O(open)-RAN(radio access network).

[0010] Figure 3a illustrates the functional configuration of an upper network node.

[0011] Figure 3b illustrates the functional configuration of a sub-network node.

[0012] Figure 4 illustrates an example of function splitting between DU and RU.

[0013] Figure 5a shows examples of control planes (C-planes).

[0014] Figure 5b shows examples of user planes (U-planes).

[0015] FIG. 6 illustrates an example of the operation of a base station in which an RRC connection has been established with multiple user devices.

[0016] Figure 7 illustrates an example of the status of a user device associated with an RRC connection.

[0017] FIG. 8 illustrates an example of the operation of a base station and a user device for exchanging information regarding the duration of a timer for RRC disconnection.

[0018] FIG. 9 illustrates a flowchart regarding the operation of a base station for changing the duration of a timer for RRC disconnection.

[0019] FIG. 10 illustrates a flowchart regarding the operation of a base station for changing the duration of a timer for RRC disconnection.

[0020] FIG. 11a illustrates a flowchart regarding the operation of a base station for changing the duration of a timer for RRC disconnection.

[0021] FIG. 11b illustrates a flowchart regarding the operation of a base station for changing the duration of a timer for RRC disconnection.

[0022] FIG. 12 illustrates an example of the operation of a base station for grouping multiple user devices.

[0023] The terms used in this disclosure are used merely to describe specific embodiments and are not intended to limit the scope of other embodiments. A singular expression may include a plural expression unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by those skilled in the art described in this disclosure. Terms used in this disclosure that are defined in a general dictionary may be interpreted as having the same or similar meaning as they have in the context of the relevant technology, and are not to be interpreted in an ideal or overly formal sense unless explicitly defined in this disclosure. In some cases, even terms defined in this disclosure are not to be interpreted to exclude the embodiments of this disclosure.

[0024] In the various embodiments of the present disclosure described below, a hardware-based approach is described as an example. However, since the various embodiments of the present disclosure include techniques using both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0025] Terms used in the following description to refer to signals (e.g., signal, information, message, signaling), terms referring to resources (e.g., symbol, slot, subframe, radio frame, subcarrier, RE (resource element), RB (resource block), BWP (bandwidth part), occasion), terms for operation states (e.g., step, operation, procedure), terms referring to data (e.g., packet, user stream, information, bit, symbol, codeword), terms referring to channels, terms referring to network entities, terms referring to device components, etc., are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0026] Additionally, in this disclosure, expressions of "greater than" or "less than" may be used to determine whether a specific condition is satisfied or fulfilled; however, this is merely for the purpose of expressing an example and does not exclude descriptions of "greater than" or "less than." Conditions described as "greater than" may be replaced with "greater than," conditions described as "less than" may be replaced with "less than," and conditions described as "greater than and less than" may be replaced with "greater than and less than." Furthermore, "A" to "B" below refer to at least one of elements from A (including A) to B (including B). Below, "C" and / or "D" refers to including at least one of "C" or "D," i.e., {"C", "D", "C" and "D"}.

[0027] The present disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project), xRAN (extensible radio access network), O-RAN (open-radio access network), but these are merely illustrative examples. Various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0028] Figure 1 illustrates an example of a wireless communication system.

[0029] Referring to FIG. 1, FIG. 1 illustrates a base station (110) and a terminal (120) as part of nodes using a wireless channel in a wireless communication system. FIG. 1 illustrates only one base station, but the wireless communication system may include other base stations identical or similar to the base station (110).

[0030] A base station (110) is a network infrastructure that provides wireless access to a terminal (120). The base station (110) has coverage defined based on the distance over which it can transmit signals. In addition to being a base station, the base station (110) may be referred to as an 'access point (AP)', 'eNodeB (eNB)', '5G node (5th generation node)', 'next generation nodeB (gNB)', 'wireless point', 'transmission / reception point (TRP)', or other terms having an equivalent technical meaning.

[0031] A terminal (120) is a device used by a user and communicates with a base station (110) via a wireless channel. The link from the base station (110) to the terminal (120) is referred to as a downlink (DL), and the link from the terminal (120) to the base station (110) is referred to as an uplink (UL). Additionally, although not shown in FIG. 1, the terminal (120) and another terminal can communicate with each other via a wireless channel. In this case, the link between the terminal (120) and another terminal (device-to-device link, D2D) is referred to as a sidelink, and the sidelink may be used interchangeably with the PC5 interface. In some other embodiments, the terminal (120) may be operated without user involvement. According to one embodiment, the terminal (120) is a device that performs machine type communication (MTC) and may not be carried by the user. In addition, according to one embodiment, the terminal (120) may be a narrowband (NB)-Internet of Things (IoT) device.

[0032] The terminal (120) may be referred to as 'user equipment (UE)', 'customer premises equipment (CPE)', 'mobile station', 'subscriber station', 'remote terminal', 'wireless terminal', 'electronic device', or 'user device' or other terms having an equivalent technical meaning.

[0033] The base station (110) can perform beamforming with the terminal (120). The base station (110) and the terminal (120) can transmit and receive wireless signals in a relatively low frequency band (e.g., FR 1 (frequency range 1) of NR). Additionally, the base station (110) and the terminal (120) can transmit and receive wireless signals in a relatively high frequency band (e.g., FR 2 (or FR 2-1, FR 2-2, FR 2-3), FR 3) of NR) and a millimeter wave (mmWave) band (e.g., 28 GHz, 30 GHz, 38 GHz, 60 GHz)). To improve channel gain, the base station (110) and the terminal (120) can perform beamforming. Here, beamforming may include transmit beamforming and receive beamforming. The base station (110) and the terminal (120) can impart directivity to the transmitted signal or the received signal. To this end, the base station (110) and the terminal (120) can select serving beams through a beam search or beam management procedure. After the serving beams are selected, subsequent communication can be performed through a resource that has a QCL relationship with the resource that transmitted the serving beams.

[0034] If large-scale characteristics of the channel transmitting the symbol on the first antenna port can be inferred from the channel transmitting the symbol on the second antenna port, the first antenna port and the second antenna port may be evaluated to have a QCL relationship. For example, the large-scale characteristics may include at least one of a delay spread, a Doppler spread, a Doppler shift, an average gain, an average delay, and a spatial receiver parameter.

[0035] In FIG. 1, it is described that both the base station (110) and the terminal (120) perform beamforming, but the embodiments of the present disclosure are not necessarily limited thereto. In some embodiments, the terminal may or may not perform beamforming. Also, the base station may or may not perform beamforming. That is, either the base station or the terminal may perform beamforming, or neither the base station nor the terminal may perform beamforming.

[0036] In the present disclosure, a beam refers to a spatial flow of a signal in a wireless channel, formed by one or more antennas (or antenna elements), and this formation process may be referred to as beamforming. Beamforming may include at least one of analog beamforming or digital beamforming (e.g., precoding). A reference signal transmitted based on beamforming may include, for example, a demodulation-reference signal (DM-RS), a channel state information-reference signal (CSI-RS), a synchronization signal / physical broadcast channel (SS / PBCH), or a sounding reference signal (SRS). Additionally, an IE such as a CSI-RS resource or an SRS-resource may be used as a configuration for each reference signal, and such a configuration may include information associated with the beam. Information associated with a beam may refer to whether the configuration (e.g., CSI-RS resource) uses the same spatial domain filter as other configurations (e.g., other CSI-RS resources within the same CSI-RS resource set) or a different spatial domain filter, or which reference signal it is quasi-colocated with, and if so, what type (e.g., QCL type A, B, C, D).

[0037] Conventionally, in communication systems with a relatively large cell radius of base stations, each base station was installed to include the functions of a digital processing unit (or DU (digital unit / distributed unit)) and a radio frequency (RF processing unit, or RU (radio unit)). However, as high frequency bands are used in 4G (4th generation) and / or subsequent communication systems (e.g., 5G) and the cell coverage of base stations decreases, the number of base stations required to cover a specific area has increased. Consequently, the burden of installation costs for operators to install base stations has also increased. To minimize the installation costs of base stations, a structure has been proposed in which the upper network node (e.g., DU) and lower network node (e.g., RU) of a base station are separated, with one or more lower network nodes connected to a single upper network node via a wired network, and one or more geographically distributed lower network nodes deployed to cover a specific area. Hereinafter, arrangement structures and extension examples of base stations according to various embodiments of the present disclosure are described through FIGS. 2a and 2b.

[0038] FIG. 2a illustrates an interface between an upper network node and a lower network node. The interface between the upper network node and the lower network node may include a fronthaul interface. Fronthaul refers to the space between entities between a wireless LAN and a base station, unlike backhaul between a base station and a core network. FIG. 2a illustrates an example of a fronthaul structure between an upper network node (210) and one lower network node (220), but this is merely for convenience of explanation and the present disclosure is not limited thereto. In other words, an embodiment of the present disclosure may also be applied to a fronthaul structure between one upper network node and a plurality of lower network nodes. For example, an embodiment of the present disclosure may be applied to a fronthaul structure between one upper network node and two lower network nodes. Additionally, an embodiment of the present disclosure may also be applied to a fronthaul structure between one upper network node and three lower network nodes.

[0039] For example, an upper network node may include a DU (digital unit / distributed unit). An upper network node may be referred to as a DU. A lower network node may include a RU (radio unit) or an MMU (massive MIMO unit). A lower network node may be referred to as a RU or an MMU.

[0040] Referring to FIG. 2a, the base station (110) may include an upper network node (210) and a lower network node (220). The fronthole (215) between the upper network node (210) and the lower network node (220) may be operated via an Fx interface. For the operation of the fronthole (215), an interface such as eCPRI (enhanced common public radio interface) or ROE (radio over ethernet) may be used.

[0041] As communication technology develops, mobile data traffic increases, and consequently, the bandwidth requirements for the fronthaul between the digital unit and the wireless unit have increased significantly. In a deployment such as a C-RAN (centralized / cloud radio access network), the upper network node (210) performs functions for PDCP (packet data convergence protocol), RLC (radio link control), MAC (media access control), and PHY (physical), and the lower network node (220) can be implemented to perform functions for the PHY layer in addition to RF (radio frequency) functions.

[0042] The upper network node (210) may be responsible for upper layer functions of the wireless network. For example, the upper network node (210) may perform functions of the MAC layer and parts of the PHY layer. Here, parts of the PHY layer are functions of the PHY layer that are performed at a higher level, and may include, for example, channel encoding (or channel decoding), scrambling (or descrambling), modulation (or demodulation), and layer mapping (or layer demapping). According to one embodiment, if the upper network node (210) conforms to the O-RAN standard, it may be referred to as an O-DU (O-RAN DU) (or DU). The upper network node (210) may be replaced and represented as a first network entity or DU for a base station (e.g., gNB) in the embodiments of the present disclosure as necessary.

[0043] The lower network node (220) can be responsible for lower layer functions of the wireless network. For example, the lower network node (220) can perform RF functions, which are part of the PHY layer. Here, part of the PHY layer refers to functions of the PHY layer that are performed at a relatively lower level than the upper network node (210), and may include, for example, iFFT transformation (or FFT transformation), CP (cyclic prefix) insertion (CP removal), and digital beamforming. Examples of such specific functional separation are described in detail in FIG. 4. The lower network node (220) may be referred to as an 'access unit (AU)', 'access point (AP)', 'transmission / reception point (TRP)', 'remote radio head (RRH)', 'radio unit (RU)', or other terms having an equivalent technical meaning. According to one embodiment, if the sub-network node (220) conforms to the O-RAN standard, it may be referred to as an O-RU (O-RAN RU) (or RU). The sub-network node (220) may be replaced with a second network entity or RU for a base station (e.g., gNB) in the embodiments of the present disclosure as needed.

[0044] In the above example, it is described that the upper network node (210) includes a DU and the lower network node (220) includes an RU, but the embodiments of the present disclosure are not limited thereto. A base station according to the embodiments may be implemented in a distributed deployment according to a centralized unit (CU) configured to perform the functions of the upper layers of the access network (e.g., packet data convergence protocol (PDCP), radio resource control (RRC)) and a distributed unit (DU) configured to perform the functions of the lower layers. In this case, the distributed unit (DU) may include a digital unit (DU) and a radio unit (RU). Between a core network (e.g., 5G core or next generation core (NGC)) and a radio network (RAN), the base station may be implemented in a structure in which the CU, DU, and RU are arranged in that order. The interface between the CU and the distributed unit (DU) may be referred to as the F1 interface.

[0045] For example, a centralized unit (CU) can be connected to one or more DUs and perform functions at a higher layer than the DUs. For instance, the CU can perform functions at the radio resource control (RRC) and packet data convergence protocol (PDCP) layers, while the DU and RU can perform functions at lower layers. The DU can perform radio link control (RLC), media access control (MAC), and some functions of the physical (PHY) layer (high PHY), while the RU can perform the remaining functions of the PHY layer (low PHY). Additionally, as an example, a digital unit (DU) can be included in a distributed unit (DU) depending on the distributed deployment implementation of the base station. The following description describes the operations of DU and RU unless otherwise defined, but various embodiments of the present disclosure may be applied to both base station deployments including CU and deployments where DU is directly connected to the core network (i.e., implemented by integrating CU and DU into a single entity base station (e.g., NG-RAN node)).

[0046] FIG. 2b illustrates a fronthall interface of an O(open)-RAN(radio access network). An eNB or gNB is exemplified as a base station (110) according to distributed deployment.

[0047] Referring to FIG. 2b, the base station (110) may include an O-DU (251) and O-RUs (253-1, …, 253-n). For convenience of explanation, the operation and function of the O-RU (253-1) may be understood as an explanation for each of the other O-RUs (e.g., O-RU (253-n)).

[0048] The O-DU (251) is a logical node containing functions among the functions of the base station (e.g., eNB, gNB) according to FIG. 4 described below, excluding those exclusively allocated to the O-RU (253-1). The O-DU (251) can control the operation of the O-RUs (253-1, …, 253-n). The O-DU (251) may be referred to as a lower layer split (LLS) central unit (CU). The O-RU (253-1) is a logical node containing a subset of the functions of the base station (e.g., eNB, gNB) according to FIG. 4 described below. Real-time aspects of control plane (C-plane) communication and user plane (U-plane) communication with the O-RU (253-1) can be controlled by the O-DU (251).

[0049] O-DU (251) can communicate with O-RU (253-1) through an LLS interface. The LLS interface corresponds to a fronthall interface. The LLS interface refers to a logical interface between O-DU (251) and O-RU (253-1) utilizing lower layer functional split (i.e., intra-PHY based functional split). LLS-C between O-DU (251) and O-RU (253-1) provides a C-plane through the LLS interface. LLS-U between O-DU (251) and O-RU (253-1) provides a U-plane through the LLS interface.

[0050] In FIG. 2b, to explain the O-RAN, the entities of the base station (110) are described as O-DU and O-RU. However, these designations are not to be interpreted as limiting the embodiments of the present disclosure. In the embodiments described below, it is understood that the operations of the upper network node (210) may be performed by the O-DU (251). The description of the upper network node (210) may be applied to the O-DU (251). Likewise, in the embodiments described below, it is understood that the operations of the lower network node (220) may be performed by the O-RU (253-1). The description of the lower network node (220) may be applied to the O-DU (253-1).

[0051] FIG. 3a illustrates the functional configuration of an upper network node. The configuration exemplified in FIG. 3a can be understood as the configuration of the upper network node (210) of FIG. 2a (or the O-DU (250) of FIG. 2b) as part of a base station. Terms such as '...part', '...unit' used below refer to a unit that processes at least one function or operation, which may be implemented in hardware or software, or a combination of hardware and software.

[0052] Referring to FIG. 3a, the upper network node (210) may include a transceiver (310), memory (320), and a processor (330). The upper network node (210) may include a digital unit / distributed unit (DU). The upper network node may be referred to as a DU.

[0053] The transceiver (310) can perform functions for transmitting and receiving signals in a wired communication environment. The transceiver (310) may include a wired interface for controlling a direct connection between devices through a transmission medium (e.g., copper wire, optical fiber). For example, the transceiver (310) can transmit an electrical signal to another device through a copper wire or perform conversion between an electrical signal and an optical signal. An upper network node (210) can communicate with a lower network node (220) through the transceiver (310). In an example, though not limited to, if the upper network node (210) is a DU, the upper network node (210) can be connected to a core network or a centralized node of a distributed deployment (e.g., CU) through the transceiver (310).

[0054] The transceiver (310) may perform functions for transmitting and receiving signals in a wireless communication environment. For example, the transceiver (310) may perform conversion functions between baseband signals and bit sequences according to the physical layer specifications of the system. For example, when transmitting data, the transceiver (310) generates complex symbols by encoding and modulating the transmitted bit sequence. Also, when receiving data, the transceiver (310) restores the received bit sequence by demodulating and decoding the baseband signal. Additionally, the transceiver (310) may include multiple transmission and reception paths. Also, according to one embodiment, the transceiver (310) may be connected to a core network or to other nodes (e.g., an integrated access backhaul).

[0055] The transceiver (310) can transmit and receive signals. For example, the transceiver (310) can transmit a management plane (M-plane) message. For example, the transceiver (310) can transmit a synchronization plane (S-plane) message. For example, the transceiver (310) can transmit a control plane (C-plane) message. For example, the transceiver (310) can transmit a user plane (U-plane) message. For example, the transceiver (310) can receive a user plane message. Although only the transceiver (310) is shown in FIG. 3a, according to other implementation examples, the upper network node (210) may include two or more transceivers.

[0056] The transceiver (310) transmits and receives signals as described above. Accordingly, all or part of the transceiver (310) may be referred to as a 'communication unit', 'transmitter unit', 'receiver unit', or 'transmitter / receiver unit'. Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean that processing as described above is performed by the transceiver (310).

[0057] Although not illustrated in FIG. 3a, the transceiver (310) may further include a backhaul transceiver for connecting to a core network or another base station. The backhaul transceiver provides an interface for communicating with other nodes within the network. That is, the backhaul transceiver converts a sequence of bits transmitted from a base station to another node, e.g., another access node, another base station, an upper node, a core network, etc., into a physical signal, and converts a physical signal received from another node into a sequence of bits.

[0058] The memory (320) stores data such as basic programs, applications, and configuration information for the operation of the upper network node (210). The memory (320) may be referred to as a storage unit. The memory (320) may be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Additionally, the memory (320) provides the stored data upon the request of the processor (330).

[0059] The processor (330) controls the overall operations of the upper network node (210). The processor (380) may be referred to as the control unit. For example, the processor (330) transmits and receives signals through the transceiver (310) (or through the backhaul communication unit). Additionally, the processor (330) writes and reads data to and from memory (320). Furthermore, the processor (330) can perform the functions of the protocol stack required by the communication standard. Although only the processor (330) is shown in FIG. 3a, according to other implementation examples, the upper network node (210) may include two or more processors.

[0060] The configuration of the upper network node (210) shown in FIG. 3a is merely an example, and the examples of upper network nodes performing embodiments of the present disclosure are not limited to the configuration shown in FIG. 3a. In some embodiments, some configurations may be added, deleted, or changed.

[0061] FIG. 3b illustrates the functional configuration of a sub-network node. The configuration exemplified in FIG. 3b can be understood as the configuration of the sub-network node (220) of FIG. 2b (or the O-RU (253-1)) of FIG. 2b as part of a base station. Terms such as '...part', '...unit' used below refer to a unit that processes at least one function or operation, which may be implemented in hardware or software, or a combination of hardware and software.

[0062] Referring to FIG. 3b, the sub-network node (220) may include an RF transceiver (360), a fronthole transceiver (365), a memory (370), and a processor (380). For example, the RF transceiver (360) may be referred to as a wireless transceiver. The fronthole transceiver (365) may be referred to as an optical transceiver.

[0063] The RF transceiver (360) performs functions for transmitting and receiving signals through a wireless channel. For example, the RF transceiver (360) upconverts a baseband signal into an RF band signal and transmits it through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal. For example, the RF transceiver (360) may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0064] The RF transceiver (360) may include a plurality of transmission and reception paths. Furthermore, the RF transceiver (360) may include an antenna section. The RF transceiver (360) may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the RF transceiver (360) may be composed of a digital circuit and an analog circuit (e.g., a radio frequency integrated circuit (RFIC)). Here, the digital circuit and the analog circuit may be implemented in a single package. Additionally, the RF transceiver (360) may include a plurality of RF chains. The RF transceiver (360) may perform beamforming. The RF transceiver (360) may apply beamforming weights to a signal to give directionality to the signal to be transmitted and received according to the settings of the processor (380). According to one embodiment, the RF transceiver (360) may include an RF (radio frequency) block (or RF section).

[0065] According to one embodiment, the RF transceiver (360) can transmit and receive signals over a radio access network. For example, the RF transceiver (360) can transmit a downlink signal. The downlink signal may include a synchronization signal (SS), a reference signal (RS) (e.g., CRS (cell-specific reference signal), DM (demodulation)-RS), system information (e.g., MIB, SIB, RMSI (remaining system information), OSI (other system information)), a configuration message, control information, or downlink data. Additionally, for example, the RF transceiver (360) can receive an uplink signal. The uplink signal may include random access-related signals (e.g., random access preamble (RAP) (or Msg1 (message 1)), Msg3 (message 3)), reference signals (e.g., sounding reference signal (SRS), DM-RS), or power headroom report (PHR). Although only an RF transceiver (360) is shown in FIG. 3b, according to other embodiments, the sub-network node (220) may include two or more RF transceivers.

[0066] According to the embodiments, the RF transceiver (460) may transmit RIM-RS. The RF transceiver (460) may transmit a first type of RIM-RS (e.g., 3GPP RIM-RS type 1) to indicate the detection of distant interference. The RF transceiver (460) may transmit a second type of RIM-RS (e.g., 3GPP RIM-RS type 2) to indicate the presence or absence of distant interference.

[0067] The fronthall transceiver (365) can transmit and receive signals. According to one embodiment, the fronthall transceiver (365) can transmit and receive signals on the fronthall interface. For example, the fronthall transceiver (365) can receive management plane (M-plane) messages. For example, the fronthall transceiver (365) can receive synchronization plane (S-plane) messages. For example, the fronthall transceiver (365) can receive control plane (C-plane) messages. For example, the fronthall transceiver (365) can transmit user plane (U-plane) messages. For example, the fronthall transceiver (365) can receive user plane messages. Although only the fronthole transceiver (365) is shown in FIG. 3b, according to other implementation examples, the lower network node (220) may include two or more fronthole transceivers.

[0068] The RF transceiver (360) and the fronthall transceiver (365) transmit and receive signals as described above. Accordingly, all or part of the RF transceiver (360) and the fronthall transceiver (365) may be referred to as a 'communication unit', 'transmitter unit', 'receiver unit', or 'transmitter unit'. Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean that processing as described above is performed by the RF transceiver (360). In the following description, transmission and reception performed via a wireless channel are used to mean that processing as described above is performed by the RF transceiver (360).

[0069] Memory (370) stores data such as basic programs, applications, and configuration information for the operation of the sub-network node (220). Memory (370) may be referred to as a storage unit. Memory (370) may be composed of volatile memory, non-volatile memory, or a combination of volatile and non-volatile memory. Additionally, memory (370) provides stored data upon request from the processor (380). According to one embodiment, memory (370) may include memory for conditions, commands, or configuration values ​​related to the SRS transmission method.

[0070] The processor (380) controls the overall operations of the sub-network node (220). The processor (380) may be referred to as a control unit. For example, the processor (380) transmits and receives signals through the RF transceiver (360) or the fronthall transceiver (365). Additionally, the processor (380) writes and reads data to and from the memory (370). Furthermore, the processor (380) can perform the functions of the protocol stack required by the communication standard. Although only the processor (380) is shown in FIG. 3b, according to other implementation examples, the sub-network node (220) may include two or more processors. The processor (380) may be a set of instructions or code stored in the memory (370), or a storage space storing instructions / code or instructions / code that are temporarily resided in the processor (380), or may be part of the circuitry constituting the processor (380). Additionally, the processor (380) may include various modules for performing communication. The processor (380) may control the lower network node (220) to perform operations according to the embodiments described below.

[0071] The configuration of the sub-network node (220) shown in FIG. 3b is merely an example, and the examples of RUs performing embodiments of the present disclosure are not limited to the configuration shown in FIG. 3b. In some embodiments, some configurations may be added, deleted, or changed.

[0072] FIG. 4 illustrates an example of a function split between a DU and an RU. The DU may be an example of an upper network node (210) of FIG. 2a and FIG. 3a. The RU may be an example of a lower network node (220) of FIG. 2a and FIG. 3b.

[0073] As wireless communication technology advances (e.g., 5G(5 thWith the introduction of generation (or NR (new radio)) communication systems, the frequency band used has increased even further. As the cell radius of base stations has become very small, the number of RUs required for installation has increased even further. In addition, in 5G communication systems, the amount of data transmitted has increased by more than 10 times, so the transmission capacity of the wired network transmitted to the fronthaul has increased significantly. Due to the factors described above, the installation cost of the wired network in 5G communication systems can increase significantly. Therefore, to reduce the transmission capacity of the wired network and lower the installation cost of the wired network, 'function splitting' can be utilized to reduce the transmission capacity of the fronthaul by transferring some functions of the DU's modem to the RU.

[0074] To reduce the burden on the DU, the role of the RU, which is traditionally responsible only for RF functions, can be extended to include some physical layer functions. As the RU performs higher-layer functions, its throughput increases, which can increase transmission bandwidth in the fronthall while simultaneously lowering latency requirements due to response processing. On the other hand, as the RU performs higher-layer functions, virtualization benefits decrease, and the size, weight, and cost of the RU increase. Considering the trade-offs between the aforementioned advantages and disadvantages, it is required to implement optimal functional separation.

[0075] Referring to FIG. 4, functional separations at the physical layer below the MAC layer are illustrated. For the downlink (DL) that transmits a signal to a terminal via a wireless network, the base station may sequentially perform channel encoding / scrambling, modulation, layer mapping, antenna mapping, RE mapping, digital beamforming (e.g., precoding), iFFT transformation / CP insertion, and RF conversion. For the uplink (UL) that receives a signal from a terminal via a wireless network, the base station may sequentially perform RF conversion, FFT transformation / CP removal, digital beamforming (pre-combining), RE demapping, channel estimation, layer demapping, demodulation, and decoding / scrambling. The separation of uplink functions and downlink functions may be defined in various types based on the needs of vendors, discussions in specifications, etc., according to the trade-offs described above.

[0076] In the first function separation (405), the RU performs RF functions and the DU performs PHY functions. The first function separation is substantially such that no PHY functions are implemented within the RU, and may be referred to as Option 8, for example. In the second function separation (410), the RU performs iFFT transform / CP insertion in the DL of the PHY functions and FFT transform / CP removal in the UL, and the DU performs the remaining PHY functions. For example, the second function separation (410) may be referred to as Option 7-1. In the third function separation (420a), the RU performs iFFT transform / CP insertion in the DL of the PHY functions and FFT transform / CP removal and digital beamforming in the UL, and the DU performs the remaining PHY functions. For example, the third function separation (420a) may be referred to as Option 7-2x Category A. In the fourth function separation (420b), the RU performs digital beamforming in both the DL and UL, and the DU performs higher PHY functions after digital beamforming. For example, the fourth function separation (420b) may be referred to as Option 7-2x Category B. In the fifth function separation (425), the RU performs RE mapping (or RE demapping) in both the DL and UL, and the DU performs higher PHY functions after RE mapping (or RE demapping). For example, the fifth function separation (425) may be referred to as Option 7-2. In the sixth function separation (430), the RU performs modulation (or demodulation) in both the DL and UL, and the DU performs higher PHY functions after modulation (or demodulation). For example, the sixth function separation (430) may be referred to as Option 7-3. In the seventh function separation (440), the RU performs encoding / scrambling (or decoding / scrambling) in both the DL and UL, and the DU performs subsequent upper PHY functions up to modulation (or demodulation). For example, the seventh function separation (440) may be referred to as Option 6.

[0077] According to one embodiment, when high-volume signal processing is expected, such as with an FR 1 MMU, functional separation at a relatively high level (e.g., fourth functional separation (420b)) may be required to reduce fronthall capacity. Additionally, functional separation at too high a level (e.g., sixth functional separation (430)) may result in a complex control interface and may cause a burden on the implementation of the RU due to the inclusion of multiple PHY processing blocks within the RU; therefore, appropriate functional separation may be required depending on the arrangement and implementation method of the DU and RU.

[0078] According to one embodiment, if the precoding of data received from the DU cannot be processed (i.e., if there is a limit to the RU's precoding capability), a third function separation (420a) or a lower function separation (e.g., a second function separation (410)) may be applied. Conversely, if there is a capability to process the precoding of data received from the DU, a fourth function separation (420b) or a higher function separation (e.g., a sixth function separation (430)) may be applied.

[0079] In the following disclosure, unless otherwise limited, embodiments are described based on a third function separation (420a) (which may be referred to as Category A (category A, CAT-A)) or a fourth function separation (420b) (which may be referred to as Category B (category B, CAT-B)) for performing beamforming processing in the RU. The O-RAN specification distinguishes types of O-RUs based on whether the precoding function is located at the interface of the O-DU or at the interface of the O-RU. An O-RU in which precoding is not performed (i.e., low complexity) may be referred to as a CAT-A O-RU. An O-RU in which precoding is performed may be referred to as a CAT-B O-RU.

[0080] Hereinafter, the term "upper-PHY" refers to physical layer processing performed in the DU of the fronthall interface. For example, the upper-PHY may include FEC encoding / decoding, scrambling, and modulation / demodulation. Hereinafter, the term "lower-PHY" refers to physical layer processing performed in the RU of the fronthall interface. For example, the lower-PHY may include FFT / iFFT, digital beamforming, PRACH (physical random access channel) extraction, and filtering. However, the above-described criteria do not exclude embodiments through other functional separations. The functional configuration, signaling, or operation of the embodiments described below may be applied not only to the third functional separation (420a) or the fourth functional separation (420b) but also to other functional separations.

[0081] Figure 5a shows examples of control planes (C-planes).

[0082] Referring to FIG. 5a, in the C-plane, the terminal (120) and the AMF (235) can perform NAS (non-access stratum) signaling. In the C-plane, the terminal (120) and the base station (110) can perform communication according to a specified protocol in the RRC layer, PDCP layer, RLC layer, MAC layer, and PHY layer, respectively.

[0083] The main functions of the RRC layer may include at least some of the following functions.

[0084] - Broadcasting system information related to AS (Access Stratum) and NAS

[0085] - Paging initiated by 5GC (5G Core) or NG-RAN (Next Generation-Radio Access network)

[0086] - Establishment, maintenance, and release of the RRC connection between the UE and NG-RAN, including, specifically, control over RLC, MAC, and PHY:

[0087] - Adding, modifying, and removing Carrier Aggregation

[0088] - Add, modify, and disable dual connectivity between NR or E-UTRA and NR.

[0089] - Security features including Key Management;

[0090] - Setup, configuration, maintenance, and release of SRB (Signaling Radio Bearer) and DRB (Data Radio Bearer)

[0091] - Movement functions including the following:

[0092] - Handover and context transfer;

[0093] - UE cell selection and re-selection and cell selection and re-selection control;

[0094] - Mobility between RATs.

[0095] - QoS (quality of service) management function;

[0096] - UE measurement reporting and control of reporting;

[0097] - Radio link failure detection and recovery

[0098] - Send messages from / to UE to / from NAS.

[0099] The main functions of the PDCP layer may include at least some of the following functions.

[0100] - Header compression and decompression features (ROHC only)

[0101] - User data transfer function (Transfer of user data)

[0102] - Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0103] - Out-of-sequence delivery of upper layer PDUs

[0104] - Reordering function (PDCP PDU reordering for reception)

[0105] - Duplicate detection function (Duplicate detection of lower layer SDUs)

[0106] - Retransmission of PDCP SDUs

[0107] - Encryption and decryption functions (Ciphering and deciphering)

[0108] - Timer-based SDU discard in uplink.

[0109] The main functions of the RLC layer may include at least some of the following functions.

[0110] - Data transfer function (Transfer of upper layer PDUs)

[0111] - Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0112] - Out-of-sequence delivery of upper layer PDUs

[0113] - ARQ function (Error Correction through ARQ)

[0114] - Concatenation, segmentation, and reassembly functions of RLC SDUs

[0115] - Re-segmentation function (Re-segmentation of RLC data PDUs)

[0116] - Reordering function (Reordering of RLC data PDUs)

[0117] - Duplicate detection

[0118] - Error detection function (Protocol error detection)

[0119] - RLC SDU discard function

[0120] RLC re-establishment function

[0121] The MAC layer can be connected to multiple RLC layer devices configured in a terminal, and the main functions of the MAC may include at least some of the following functions.

[0122] - Mapping function between logical channels and transport channels

[0123] - Multiplexing and demultiplexing of MAC SDUs

[0124] - Scheduling information reporting function

[0125] Error correction through HARQ

[0126] - Priority handling between logical channels of one UE

[0127] - Priority handling between UEs by means of dynamic scheduling

[0128] - MBMS service identification function

[0129] - Transport format selection function

[0130] - Padding

[0131] The physical layer can perform operations such as channel coding and modulating upper-layer data, converting it into OFDM symbols for transmission over a wireless channel, or demodulating OFDM symbols received through a wireless channel, channel decoding, and transmitting them to the upper layer.

[0132] Figure 5b shows examples of user planes (U-planes).

[0133] Referring to FIG. 5b, in a U-plane, the terminal (120) and the base station (110) can perform communication according to a specified protocol in each of the SDAP layer, PDCP layer, RLC layer, MAC layer, and PHY layer. For the PDCP layer, RLC layer, MAC layer, and PHY layer, excluding the SDAP layer, the description of FIG. 5a may be referenced.

[0134] The SDAP layer can provide QoS flow for 5GC. A single protocol entity of SDAP can be configured for each individual PDU session, and the functions of the SDAP layer may include at least some of the following functions.

[0135] - Mapping between QoS flow and data wireless bearer;

[0136] - Displays QoS flow ID (identifier) ​​(QFI) in both DL and UL packets.

[0137] According to one embodiment, a base station (e.g., base station (110) of FIG. 1) can establish a connection with a plurality of user devices (e.g., terminal (120) of FIG. 1). If the number of user devices connected to the base station is too large, wireless resources may not be used efficiently. For example, at least some of the user devices among the plurality of user devices may not transmit or receive signals with the base station. If a radio resource control (RRC) connection is maintained with said at least some of the user devices, wireless resources may be wasted. Therefore, the following specification will describe a technical feature for quickly disconnecting an RRC connection with at least some of the user devices that do not transmit and / or receive signals with the base station.

[0138] FIG. 6 illustrates an example of the operation of a base station in which an RRC connection has been established with multiple user devices.

[0139] Referring to FIG. 6, the network environment (600) may include a core network (630) (e.g., an access and mobility management function (AMF) and a user plane function (UPF)), a base station (610), and / or a plurality of user devices (620). For example, the AMF of the core network (630) may be configured to perform mobility management for the plurality of user devices (620). The UPF of the core network (630) may be configured to perform traffic management for the plurality of user devices (620). For example, the base station (610) may correspond to the base station (110) of FIG. 1. Each of the plurality of user devices (620) may correspond to the terminal (120) of FIG. 1.

[0140] According to one embodiment, a base station (610) can establish an RRC connection with a plurality of user devices (620). Depending on the RRC connection, the state of each of the plurality of user devices (620) can be set to an RRC connection state. For example, the base station (610) can configure (or provide) a cell (611). The base station (610) can establish an RRC connection with a plurality of user devices (620) located within the cell (611).

[0141] For example, the base station (610) may set a timer for disconnecting the RRC connection for a user device (e.g., user device (621)) that is not transmitting or receiving data (or signals) to the base station (610). The base station (610) may transmit the duration of the set timer to the user device. If the user device does not transmit or receive data (or signals) to the base station (610) during the said duration, the state of the user device may be set to an RRC idle state. For example, if the user device does not transmit or receive data (or signals) to the base station (610) during the said duration, the state of the user device may be changed from an RRC connected state to an RRC idle state. As the state of the user device changes to an RRC idle state, the RRC connection may be disconnected. As the RRC connection between the base station (610) and the user device is disconnected, the efficiency of wireless resource usage may be increased.

[0142] According to the above-described embodiment, the base station (610) can change the duration of the timer for RRC disconnection. For example, the base station (610) can increase or decrease the duration of the timer for RRC disconnection.

[0143] For example, if the base station (610) increases the duration of the timer for disconnecting the RRC connection for the user device (621), the RRC connection between the user device (621) and the base station (610) may not be disconnected quickly. The time during which the user device (621) maintains the RRC connection state may be increased.

[0144] For example, if the base station (610) reduces the duration of the timer for disconnecting the RRC connection for the user device (621), the RRC connection between the user device (621) and the base station (610) can be quickly disconnected. The time the user device (621) maintains the RRC connection state can be reduced.

[0145] According to one embodiment, the base station (610) can set the duration of a timer for RRC disconnection for each of a plurality of user devices (620). For example, the base station (610) can set the duration of a timer for RRC disconnection for a user device (621) to a first duration. The base station (610) can set the duration of a timer for RRC disconnection for a user device distinct from the user device (621) to a second duration distinct from the first duration.

[0146] For example, the base station (610) can distinguish multiple user devices (620) based on multiple groups. The base station (610) can set the duration of a timer for RRC disconnection for each of the multiple groups.

[0147] In the following specification, an example of the operation of a base station (610) for setting the duration of a timer for RRC disconnection for each of the plurality of user devices (620) (or for the plurality of groups) will be described. First, in FIG. 7, an example of the state of a user device related to an RRC connection will be described.

[0148] Figure 7 illustrates an example of the status of a user device associated with an RRC connection.

[0149] Referring to FIG. 7, a user device (621) (e.g., one of the multiple user devices (620) of FIG. 6) may operate based on multiple states related to an RRC connection. For example, the multiple states may include an RRC connected state (701), an RRC idle state (702), and an RRC inactive state (703).

[0150] In the RRC connection state (701), the user device (621) can transmit and receive data with the base station (610). The base station (610) can manage the location of the user device (621) or perform at least one procedure related to data transmission with the user device (621) (e.g., handover, or power management).

[0151] For example, in an RRC connection state (701), the user device (621) can provide channel quality and feedback information to the base station (610). For example, the user device (621) can perform neighbor cell and / or L2 U2N (UE-to-network) relay measurements and measurement reports. For example, the user device (621) can collect system information. For example, the user device (621) can perform immediate MDT (minimization of drive tests) measurements along with available location reports.

[0152] In the RRC idle state (702), the RRC connection between the user device (621) and the base station (610) may be disconnected. The user device (621) may periodically receive system information and / or cell change information from the base station (610). Based on the system information and / or cell change information, the user device (621) may make preparations to establish an RRC connection with the base station (610). If data transmission and / or data reception is required, the user device (621) may change the state of the user device (621) from the RRC idle state (702) to the RRC connection state (701).

[0153] For example, in the RRC idle state (702), the user device (621) can monitor short messages transmitted to the P-RNTI (paging radio network temporary identifier) ​​via DCI (downlink control information). For example, the user device (621) can monitor the paging channel for CN (core network) paging using the 5G-S-TMSI (5G-S-temporary mobile subscription identifier), except when operating as an L2 U2N (UE-to-network) remote UE. For example, the user device (621) can perform neighbor cell measurements and / or cell (re)selection. For example, the user device (621) can collect system information and transmit SI (system information) requests.

[0154] In the RRC inactive state (703), the user device (621) may retain at least some of the connection information with the base station (610). The RRC inactive state (703) may correspond to an intermediate state between the RRC connected state (701) and the RRC idle state (702). If data transmission and / or data reception is required, the user device (621) may change the state of the user device (621) from the RRC inactive state (703) to the RRC connected state (701). The time taken to change from the RRC inactive state (703) to the RRC connected state (701) may be shorter than the time taken to change from the RRC idle state (702) to the RRC connected state (701).

[0155] According to one embodiment, the user device (621) may change the state of the user device (621) from an RRC connected state (701) to an RRC idle state (702) based on not transmitting or receiving data with the base station (610) during the duration of the timer for RRC disconnection. In FIG. 8, an example of the operation of the base station (610) for transmitting information regarding the duration of the timer for RRC disconnection to the user device (621) will be described.

[0156] FIG. 8 illustrates an example of the operation of a base station and a user device for exchanging information regarding the duration of a timer for RRC disconnection.

[0157] Referring to FIG. 8, the base station (610) can determine the duration of the timer for RRC disconnection. The base station (610) can transmit information regarding the duration of the timer for RRC disconnection to the user device (621).

[0158] According to one embodiment, the base station (610) may transmit information regarding the duration of a timer for RRC disconnection to the user device (621) via an RRC setup message. For example, the RRC setup message may be used to establish an RRC connection. For example, the base station (610) may transmit the RRC setup message to the user device (621) to establish an RRC connection with the user device (621). The RRC setup message may be used to establish a signaling radio bearer (SRB) 1. The RRC setup message may include information regarding the duration of a timer for RRC disconnection.

[0159] According to one embodiment, the base station (610) may transmit information regarding the duration of a timer for RRC disconnection to the user device (621) via an RRC reconfiguration message. For example, the RRC reconfiguration message may be used to modify the RRC connection. For example, the base station (610) may transmit the RRC reconfiguration message to the user device (621) to modify the RRC connection. The RRC reconfiguration message may include information regarding the duration of a timer for RRC disconnection. The RRC reconfiguration message may include information regarding measurement configuration, mobility control, radio resource configuration, and / or access stratum (AS) security configuration.

[0160] For example, an RRC setup message may include information regarding a reference duration for multiple user devices (620). An RRC reconfiguration message may include information for changing the duration of a timer for RRC disconnection from the reference duration. An RRC reconfiguration message may include information for increasing (or decreasing) the duration of a timer for RRC disconnection from the reference duration. An RRC reconfiguration message may include information regarding the increased (or decreased) duration.

[0161] According to one embodiment, the user device (621) may change the state of the user device (621) from an RRC connected state to an RRC idle state based on not transmitting or receiving data with the base station (610) during the duration of the timer for RRC disconnection. As the state of the user device (621) changes to an RRC idle state, the RRC connection between the base station (610) and the user device (621) may be disconnected.

[0162] In the examples described above, the duration of the timer for RRC disconnection can be set to one of 1 second, 2 seconds, 3 seconds, 5 seconds, 7 seconds, 10 seconds, 15 seconds, 20 seconds, 40 seconds, 50 seconds, 60 seconds, 80 seconds, 100 seconds, 120 seconds, 150 seconds, and 180 seconds.

[0163] FIG. 9 illustrates a flowchart regarding the operation of a base station for changing the duration of a timer for RRC disconnection.

[0164] Referring to FIG. 9, in operation 901, the base station (610) can identify the number of multiple user devices (620) that have established an RRC connection with the base station (610). For example, if the number of multiple user devices (620) that have established an RRC connection with the base station (610) is greater than a reference number, system resources and / or wireless resources may be insufficient. Therefore, the base station (610) can identify the number of multiple user devices (620) that have established an RRC connection with the base station (610) in order to adjust the number of multiple user devices (620) that have established an RRC connection.

[0165] In operation 902, the base station (610) may reduce the duration of the timer for disconnecting the RRC connection for each of the plurality of user devices (620). The timer for disconnecting the RRC connection may be referred to as a user inactivity timer (or data inactivity timer).

[0166] According to one embodiment, the base station (610) can quickly disconnect the RRC connection for each of the plurality of user devices (620) by reducing the duration of the timer for disconnecting the RRC connection.

[0167] According to one embodiment, the base station (610) may reduce the duration of the timer for disconnecting the RRC connection by a specified rate. For example, the base station (610) may reduce the duration of the timer for disconnecting the RRC connection by a specified rate until the number of multiple user devices (620) with established RRC connections changes to a reference number or less. For example, the base station (610) may not set the duration for disconnecting the RRC connection to be smaller than the minimum duration. The base station (610) may set the duration for disconnecting the RRC connection to be greater than or equal to the minimum duration. For example, the minimum duration may be set at the base station (610). For example, the minimum duration may be set considering the RRC overhead.

[0168] According to one embodiment, the base station (610) may gradually reduce the duration for disconnecting the RRC connection. For example, the base station (610) may repeatedly reduce the duration for disconnecting the RRC connection based on a specified ratio. For example, the base station (610) may reduce the duration for disconnecting the RRC connection by a first ratio (e.g., 10%). After reducing the duration for disconnecting the RRC connection by the first ratio (e.g., 10%), the base station (610) may identify that the reduced duration has elapsed. After the reduced duration has elapsed, the base station (610) may identify whether the number of multiple user devices (620) is less than or equal to a reference number. Based on identifying that the number of multiple user devices (620) exceeds the reference number, the base station (610) may reduce the duration for disconnecting the RRC connection by a second ratio (e.g., 20%).

[0169] According to one embodiment, the base station (610) can identify that the number of multiple user devices (620) is less than or equal to a reference number. Based on identifying that the number of multiple user devices (620) is less than or equal to a reference number, the base station (610) can increase the duration for disconnecting the RRC connection for each of the multiple user devices (620). For example, the base station (610) can increase the duration for disconnecting the RRC connection stepwise. For example, the base station (610) can repeatedly increase the duration for disconnecting the RRC connection based on a specified ratio. For example, the base station (610) can increase the duration for disconnecting the RRC connection by a first ratio (e.g., 10%). After increasing the duration for disconnecting the RRC connection by the first ratio (e.g., 10%), the base station (610) can identify that the increased duration has elapsed. After the increased duration has elapsed, the base station (610) can identify whether the number of multiple user devices (620) is less than or equal to the reference number. Based on identifying that the number of multiple user devices (620) is less than or equal to the reference number, the base station (610) can increase the duration for disconnecting the RRC connection by a second rate (e.g., 20%).

[0170] According to the above-described embodiment, the base station (610) can adaptively and efficiently utilize the resources of the operating system according to the number of multiple user devices (620) connected to the base station (610). By reducing the duration for disconnecting the RRC connection, the base station (610) can quickly induce the disconnection of the RRC connection for user devices that are not transmitting or receiving data. When the duration for disconnecting the RRC connection is reduced, the base station (610) can recover system resources and / or radio resources more quickly, and thus can accommodate a larger number of user devices.

[0171] FIG. 10 illustrates a flowchart regarding the operation of a base station for changing the duration of a timer for RRC disconnection.

[0172] Referring to FIG. 10, in operation 1001, the number of multiple user devices (620) that have established an RRC connection with the base station (610) can be identified. Operation 1001 may correspond to operation 901 of FIG. 9.

[0173] In operation 1002, the base station (610) can identify a user device satisfying a specified condition based on the number of multiple user devices (620) exceeding a reference number. For example, the base station (610) can identify whether the number of multiple user devices (620) exceeds a reference number. The base station (610) can identify that the number of multiple user devices (620) exceeds a reference number.

[0174] According to one embodiment, the base station (610) can identify a user device that satisfies specified conditions. For example, the base station (610) can identify a user device that provides emergency call services.

[0175] For example, the base station (610) can identify a user device in which the 5QI (5G QoS (quality of service) identifier) ​​is set to a first value (e.g., '1') or a second value (e.g., '2'). For example, the table below may be referenced for QoS characteristics associated with 5QI.

[0176] 5QIValueResource TypeDefault Priority LevelPacket Delay Budget(NOTE 3)Packet ErrorRateDefault Maximum Data Burst Volume(NOTE 2)DefaultAveraging WindowExample Services1GBR20100 ms(NOTE 11,NOTE 13)10-2 N / A2000 msConversational Voice2(NOTE 1)40150 ms(NOTE 11,NOTE 13)10 -3 N / A2000 msConversational Video (Live Streaming)33050 ms(NOTE 11,NOTE 13)10 -3 N / A2000 msReal Time Gaming, V2X messages (see TS 23.287

[0121] ).Electricity distribution - medium voltage, Process automation monitoring450300 ms(NOTE 11,NOTE 13)10 -6 N / A2000 msNon-Conversational Video (Buffered Streaming)65(NOTE 9,NOTE 12)775 ms(NOTE 7, NOTE 8)10 -2 N / A2000 msMission Critical user plane Push To Talk voice (e.g. MCPTT)66(NOTE 12)20100 ms(NOTE 10,NOTE 13)10 -2 N / A2000 msNon-Mission-Critical user plane Push To Talk voice67(NOTE 12)15100 ms(NOTE 10,NOTE 13)10 -3 N / A2000 msMission Critical Video user plane75(NOTE 14)7156150 ms (NOTE 11, NOTE 13, NOTE 15)10 -6 N / A2000 ms"Live" Uplink Streaming (e.g. TS 26.238

[0076] )7256300 ms (NOTE 11, NOTE 13, NOTE 15)10 -4N / A2000 ms"Live" Uplink Streaming (e.g. TS 26.238

[0076] )7356300 ms (NOTE 11, NOTE 13, NOTE 15)10 -8 N / A2000 ms"Live" Uplink Streaming (e.g. TS 26.238

[0076] )7456500 ms (NOTE 11, NOTE 15)10 -8 N / A2000 ms"Live" Uplink Streaming (e.g. TS 26.238

[0076] )7656500 ms (NOTE 11, NOTE 13, NOTE 15)10 -4 N / A2000 ms"Live" Uplink Streaming (e.g. TS 26.238

[0076] )5Non-GBR10100 msNOTE 10,NOTE 13)10 -6 N / AN / AIMS Signalling6(NOTE 1)60300 ms(NOTE 10,NOTE 13)10 -6 N / AN / AVideo (Buffered Streaming)TCP-based (e.g. www, e-mail, chat, ftp, p2p file sharing, progressive video, etc.)770100 ms(NOTE 10,NOTE 13)10 -3 N / AN / AVoice,Video (Live Streaming)Interactive Gaming880300 ms(NOTE 13)10 -6 N / AN / AVideo (Buffered Streaming)TCP-based (e.g. www, e-mail, chat, ftp, p2p file sharing, progressive990video, etc.)69(NOTE 9, NOTE 12)560 ms(NOTE 7, NOTE 8)10 -6N / AN / AMission Critical delay sensitive signalling (e.g. MC-PTT signalling)70(NOTE 12)55200 ms(NOTE 7,NOTE 10)10 -6 N / AN / AMission Critical Data (e.g. example services are the same as 5QI 6 / 8 / 9)796550 ms(NOTE 10,NOTE 13)10 -2 N / AN / AV2X messages (see TS 23.287

[0121] )806810 ms(NOTE 5,NOTE 10)10 -6 N / AN / ALow Latency eMBB applications Augmented Reality82Delay-critical GBR1910 ms(NOTE 4)10 -4 255 bytes2000 msDiscrete Automation (see TS 22.261 [2])832210 ms(NOTE 4)10 -4 1354 bytes(NOTE 3)2000 msDiscrete Automation (see TS 22.261 [2]);V2X messages (UE - RSU Platooning, Advanced Driving: Cooperative Lane Change with low LoA. See TS 22.186

[0111] , TS 23.287

[0121] )842430 ms(NOTE 6)10 -5 1354 bytes(NOTE 3)2000 msIntelligent transport systems (see TS 22.261 [2])85215 ms(NOTE 5)10 -5255 bytes2000 msElectricity Distribution- high voltage (see TS 22.261 [2]).V2X messages (Remote Driving. See TS 22.186

[0111] , NOTE 16, see TS 23.287

[0121] )86185 ms(NOTE 5)10 -41354 bytes2000 msV2X messages (Advanced Driving: Collision Avoidance, Platooning with high LoA. See TS 22.186

[0111] , TS 23.287

[0121] )NOTE 1: A packet which is delayed more than PDB is not counted as lost, thus not included in the PER.NOTE 2: It is required that default MDBV is supported by a PLMN supporting the related 5QIs.NOTE 3: The Maximum Transfer Unit (MTU) size considerations in clause 9.3 and Annex C of TS 23.060

[0056] are also applicable. IP fragmentation may have impacts to CN PDB, and details are provided in clause 5.6.10.NOTE 4: A static value for the CN PDB of 1 ms for the delay between a UPF terminating N6 and a 5G-AN should be subtracted from a given PDB to derive the packet delay budget that applies to the radio interface. When a dynamic CN PDB is used, see clause 5.7.3.4.NOTE 5: A static value for the CN PDB of 2 ms for the delay between a UPF terminating N6 and a 5G-AN should be subtracted from a given PDB to derive the packet delay budget that applies to the radio interface. When a dynamic CN PDB is used, see clause 5.7.3.4.NOTE 6: A static value for the CN PDB of 5 ms for the delay between a UPF terminating N6 and a 5G-AN should be subtracted from a given PDB to derive the packet delay budget that applies to the radio interface. When a dynamic CN PDB is used, see clause 5.7.3.4.NOTE 7: For Mission Critical services, it may be assumed that the UPF terminating N6 is located "close" to the 5G_AN (roughly 10 ms) and is not normally used in a long distance, home routed roaming situation. Hence a static value for the CN PDBof 10 ms for the delay between a UPF terminating N6 and a 5G_AN should be subtracted from this PDB to derive the packet delay budget that applies to the radio interface.NOTE 8: In both RRC Idle and RRC Connected mode, the PDB requirement for these 5QIs can be relaxed (but not to a value greater than 320 ms) for the first packet(s) in a downlink data or signalling burst in order to permit reasonable battery saving (DRX) techniques.NOTE 9: It is expected that 5QI-65 and 5QI-69 are used together to provide Mission Critical Push to Talk service (e.g. 5QI-5 is not used for signalling). It is expected that the amount of traffic per UE will be similar or less compared to the IMS signalling.NOTE 10: In both RRC Idle and RRC Connected mode, the PDB requirement for these 5QIs can be relaxed for the first packet(s) in a downlink data or signalling burst in order to permit battery saving (DRX) techniques.NOTE 11: In RRC Idle mode, the PDB requirement for these 5QIs can be relaxed for the first packet(s) in a downlink data or signalling burst in order to permit battery saving (DRX) techniques.NOTE 12: This 5QI value can only be assigned upon request from the network side. The UE and any application running on the UE is not allowed to request this 5QI value.NOTE 13: A static value for the CN PDB of 20 ms for the delay between a UPF terminating N6 and a 5G-AN should be subtracted from a given PDB to derive the packet delay budget that applies to the radio interface.NOTE 14: This 5QI is not supported in this Release of the specification as it is only used for transmission of V2X messages over MBMS bearers as defined in TS 23.285

[0072] but the value is reserved for future use.NOTE 15: For "live" uplink streaming (see TS 26.238

[0076] ), guidelines for PDB values of the different 5QIs correspond to the latency configurations defined in TR 26.939

[0077] . In order to support higher latency reliable streaming services (above 500ms PDB), if different PDB and PER combinations are needed these configurations will have to use non-standardised 5QIs.NOTE 16: These services are expected to need much larger MDBV values ​​to be signaled to the RAN. Support for such larger MDBV values ​​with low latency and high reliability is likely to require a suitable RAN configuration, for which, the simulation scenarios in TR 38.824

[0112] may contain some guidance.

[0177] In operation 1003, the base station (610) can determine the duration of a timer for disconnecting the RRC connection for an identified user device. For example, the base station (610) can determine the duration of a timer for disconnecting the RRC connection for a user device that satisfies a specified condition. The base station (610) can transmit information regarding the determined duration to the user device that satisfies the specified condition. For example, the base station (610) can transmit information regarding the determined duration to the user device that satisfies the specified condition via an RRC reconfiguration message.

[0178] According to one embodiment, the base station (610) can identify a user device to which an emergency call service is provided. For the user device to which an emergency call service is provided, the base station (610) can increase the duration of the timer for disconnecting the RRC connection. For example, the base station (610) can set the duration of the timer for disconnecting the RRC connection to the maximum duration for the user device to which an emergency call service is provided.

[0179] According to one embodiment, the base station (610) can identify a user device in which 5QI is set to a first value (e.g., '1') or a second value (e.g., '2'). For a user device in which 5QI is set to a first value (e.g., '1') or a second value (e.g., '2'), the base station (610) can increase the duration of a timer for disconnecting the RRC connection.

[0180] According to one embodiment, the base station (610) can set the duration of the timer for disconnecting the RRC connection based on 5QI. For example, the base station (610) can set the duration of the timer for disconnecting the RRC connection to a first duration for a first user device where 5QI is set to a first value (e.g., '1'). For example, the base station (610) can set the duration of the timer for disconnecting the RRC connection to a second duration for a second user device where 5QI is set to a second value (e.g., '2'). For example, the base station (610) can set the duration of the timer for disconnecting the RRC connection to a third duration for a third user device where 5QI is set to a third value (e.g., '3').

[0181] According to an embodiment, the base station (610) can identify a first user device to which an emergency call service is provided. The base station (610) can identify a second user device in which 5QI is set to a first value (e.g., '1') or a second value (e.g., '2'). For the first user device, the base station (610) can set the duration of the timer for disconnecting the RRC connection to the maximum duration. For the second user device, the base station (610) can increase the duration of the timer for disconnecting the RRC connection by a specified rate.

[0182] FIG. 11a illustrates a flowchart regarding the operation of a base station for changing the duration of a timer for RRC disconnection.

[0183] Referring to FIG. 11a, in operation 1101, the base station (610) can identify the number of multiple user devices (620) to which an RRC connection has been established with the base station (610). Operation 1101 may correspond to operation 901 of FIG. 9.

[0184] According to one embodiment, the base station (610) may transmit an RRC setup message to each of the plurality of user devices (620) to establish an RRC connection with the plurality of user devices (620). For example, the RRC setup message may include information about a reference duration. Based on the RRC setup message, the plurality of user devices (620) may set the duration of a timer for disconnecting the RRC connection to the reference duration.

[0185] In operation 1102, the base station (610) can identify at least one user device of a first group to which an emergency call service is provided, based on the number of multiple user devices (620) that exceed a reference number. For example, the base station (610) can identify whether the number of multiple user devices (620) exceeds a reference number. The base station (610) can identify that the number of multiple user devices (620) exceeds a reference number.

[0186] According to one embodiment, the base station (610) can identify at least one user device of a first group to which an emergency call service is provided. The base station (610) can identify at least one user device of a first group to which an emergency call service is provided among a plurality of user devices (620).

[0187] In operation 1103, the base station (610) may set the duration of the timer for disconnecting the RRC connection to a first duration for each of at least one user device in the first group. For example, the base station (610) may increase the reference duration for multiple user devices (620) according to a specified ratio. The base station (610) may determine the first duration based on increasing the reference duration according to a specified ratio. The base station (610) may change the duration of the timer for disconnecting the RRC connection from the reference duration to the first duration for each of at least one user device in the first group. The base station (610) may transmit information regarding the first duration to at least one user device in the first group. For example, the base station (610) may transmit a first RRC reconfiguration message containing information regarding the first duration to at least one user device in the first group. For example, the first duration may be set to be less than or equal to the maximum duration.

[0188] According to one embodiment, if data is not transmitted or received between the first user device and the base station (610) among at least one device of the first group during a first duration, the RRC connection between the first user device and the base station (610) may be disconnected. For example, if data is not transmitted or received between the first user device and the base station (610) among at least one device of the first group during a first duration, the first user device may set the state of the first user device to an RRC idle state. As the state of the first user device is set to an RRC idle state, the RRC connection between the first user device and the base station (610) may be disconnected.

[0189] In operation 1104, the base station (610) may set the duration of the timer for releasing the RRC connection to a second duration for each of at least one user device in the second group. For example, the base station (610) may reduce the reference duration for multiple user devices (620) according to a specified ratio. The base station (610) may determine the second duration based on reducing the reference duration according to a specified ratio. The base station (610) may change the duration of the timer for releasing the RRC connection from the reference duration to the second duration for each of at least one user device in the second group. The base station (610) may transmit information regarding the second duration to at least one user device in the second group. For example, the base station (610) may transmit a second RRC reconfiguration message containing information regarding the second duration to at least one user device in the second group. For example, the second duration may be set to be greater than or equal to the minimum duration. For example, the minimum duration can be set based on the RRC overhead.

[0190] According to one embodiment, if data is not transmitted or received between the second user device and the base station (610) among at least one device of the second group during a second duration, the RRC connection between the second user device and the base station (610) may be disconnected. For example, if data is not transmitted or received between the second user device and the base station (610) among at least one device of the second group during a second duration, the second user device may set the state of the second user device to an RRC idle state. As the state of the second user device is set to an RRC idle state, the RRC connection between the second user device and the base station (610) may be disconnected.

[0191] According to one embodiment, the base station (610) can identify one or more user devices among a plurality of user devices (620) that are provided with a service distinct from an emergency call service. For example, the base station (610) can identify at least one device among one or more user devices that has a data drop rate less than a reference drop rate as a second group.

[0192] For example, the base station (610) may identify at least one device among one or more user devices as a third group, wherein the data drop rate is greater than or equal to a reference drop rate. For at least one device in the third group, the base station (610) may set the duration of the timer for disconnecting the RRC connection to a third duration. According to an embodiment, the third duration may correspond to the first duration.

[0193] According to one embodiment, the base station (610) may increase the first duration according to a specified ratio for each of at least one user device in the first group until the number of multiple user devices (620) is identified as being less than or equal to a reference number. The base station (610) may increase the first duration according to a specified ratio for each of at least one user device in the first group within a range less than or equal to the maximum duration.

[0194] According to one embodiment, the base station (610) may reduce the second duration for each of at least one user device in the second group according to a specified ratio until the number of multiple user devices (620) is identified as being less than or equal to a reference number. The base station (610) may reduce the second duration for each of at least one user device in the second group according to a specified ratio within a range greater than or equal to the minimum duration.

[0195] According to the above-described embodiment, the base station (610) can adaptively and efficiently utilize the resources of the operating system according to the number of multiple user devices (620) connected to the base station (610). By reducing the duration for disconnecting the RRC connection, the base station (610) can quickly induce the disconnection of the RRC connection for user devices that are not transmitting or receiving data. When the duration for disconnecting the RRC connection is reduced, the base station (610) can recover system resources and / or radio resources more quickly, and thus can accommodate a larger number of user devices. According to one embodiment, the base station (610) may not allocate the entire resource considering overhead when the state of a user device changes from an RRC idle state (or RRC inactive state) to an RRC connected state.

[0196] FIG. 11b illustrates a flowchart regarding the operation of a base station for changing the duration of a timer for RRC disconnection.

[0197] Referring to FIG. 11b, in operation 1111, the base station (610) can identify the number of multiple user devices (620) to which an RRC connection has been established with the base station (610). Operation 1111 may correspond to operation 901 of FIG. 9.

[0198] In operation 1112, the base station (610) can identify whether the number of multiple user devices (620) exceeds a reference number. If the number of multiple user devices (620) with which an RRC connection has been established with the base station (610) is greater than the reference number, system resources and / or wireless resources may be insufficient. Therefore, the base station (610) can identify whether the number of multiple user devices (620) with which an RRC connection has been established with the base station (610) exceeds a reference number in order to adjust the number of multiple user devices (620) with which an RRC connection has been established.

[0199] In operation 1113, the base station (610) can set the duration of the timer for disconnecting the RRC connection to a first duration. For example, if the number of multiple user devices (620) does not exceed a reference number, the base station (610) can set the duration of the timer for disconnecting the RRC connection to a first duration for each of the multiple user devices (620). The base station (610) can determine the first duration based on increasing the reference duration set based on the RRC setup message. The base station (610) can set the duration of the timer for disconnecting the RRC connection to a determined first duration for each of the multiple user devices (620).

[0200] In operation 1114, if the number of multiple user devices (620) exceeds a reference number, the base station (610) can identify whether the user device is provided with an emergency call service. The base station (610) can identify the user device provided with an emergency call service as a first group. For example, the base station (610) can perform operation 1113 for at least one user device in the first group.

[0201] In operation 1115, the base station (610) can identify whether the data drop rate is less than a reference drop rate for a user device provided with a service distinct from the emergency call service. For example, the base station (610) can identify a user device among the user devices provided with a service distinct from the emergency call service that has a data drop rate less than the reference drop rate as a second group. The base station (610) can identify a user device among the user devices provided with a service distinct from the emergency call service that has a data drop rate greater than or equal to the reference drop rate as a third group. For example, the base station (610) can perform operation 1113 for at least one user device in the third group.

[0202] In operation 1116, the base station (610) may set the duration of the timer for disconnecting the RRC connection to a second duration for a user device whose data drop rate is less than the reference drop rate. For example, the base station (610) may set the duration of the timer for disconnecting the RRC connection to a second duration for at least one user device of the third group.

[0203] For example, the base station (610) may determine a second duration based on reducing a reference duration set based on an RRC setup message. The base station (610) may set the duration of a timer for disconnecting the RRC connection to the determined second duration for at least one user device of the third group. The second duration may be shorter than the first duration.

[0204] FIG. 12 illustrates an example of the operation of a base station for grouping multiple user devices.

[0205] Referring to FIG. 12, the base station (610) can perform grouping for multiple user devices (620) that exceed a reference number. Depending on the group, the base station (610) can set the duration of a timer for disconnecting the RRC connection.

[0206] For example, the base station (610) may set (or identify) at least one user device among a plurality of user devices (620) to which an emergency call service is provided as a first group (1201). For at least one user device in the first group (1201), the base station (610) may set the duration of a timer for disconnecting the RRC connection to a first duration.

[0207] For example, the base station (610) can identify one or more user devices among a plurality of user devices (620) that provide a service distinct from the emergency call service. The base station (610) can set (or identify) at least one user device among the one or more user devices whose data drop rate is less than the reference drop rate as a second group (1202). For at least one user device in the second group (1202), the base station (610) can set the duration of the timer for disconnecting the RRC connection to a second duration. The second duration may be shorter than the first duration.

[0208] For example, the base station (610) may set (or identify) at least one user device among one or more user devices that provide a service distinct from the emergency call service, wherein the data drop rate is greater than or equal to the reference drop rate, as a third group (1203). For at least one user device in the third group (1203), the base station (610) may set the duration of the timer for disconnecting the RRC connection to a third duration. The third duration may be longer than the second duration. According to an embodiment, the third duration may correspond to the first duration. According to an embodiment, the third duration may be shorter than the first duration and longer than the second duration.

[0209] According to one embodiment, the base station may include a transceiver, a memory including instructions and one or more storage media, and at least one processor including a processing circuit. When the instructions are executed individually or collectively by the at least one processor, the base station may be caused to identify the number of user equipment (UE) devices to which a radio resource control (RRC) connection has been established, identify at least one user equipment in a first group to which an emergency call service is provided among the user equipment devices based on the number of user equipment devices exceeding a reference number, set the duration of a timer for disconnecting the RRC connection to a first duration for each of the at least one user equipment in the first group, and set the duration of a timer for disconnecting the RRC connection to a second duration shorter than the first duration for each of the at least one user equipment in a second group distinct from the first group.

[0210] For example, when the above instructions are executed individually or collectively by the at least one processor, the base station may be configured to identify one or more user devices among the plurality of user devices that are provided with a service distinct from the emergency call service, and to identify at least one user device of the second group among the one or more user devices whose data drop rate is less than a reference drop rate.

[0211] For example, when the above instructions are executed individually or collectively by the at least one processor, the base station may be caused to identify at least one user device in a third group among the one or more user devices, wherein the data drop rate is greater than or equal to the reference drop rate, and to set the duration of a timer for disconnecting the RRC connection to a third duration for the at least one user device in the third group.

[0212] For example, the third duration may correspond to the first duration.

[0213] For example, the above instructions may cause the base station to determine the first duration based on increasing the reference duration for the plurality of user devices according to a specified ratio when executed individually or collectively by the at least one processor, and to determine the second duration based on decreasing the reference duration according to the specified ratio.

[0214] For example, when the above instructions are executed individually or collectively by the at least one processor, the base station may be caused to increase the first duration according to the specified ratio for each of the at least one user device in the first group and decrease the second duration according to the specified ratio for each of the at least one user device in the second group until the number of the plurality of user devices is identified as being less than or equal to the reference number.

[0215] For example, the above instructions may cause the base station to transmit a first RRC reconstruction message containing information regarding the first duration to each of the at least one user device of the first group, and to transmit a second RRC reconstruction message containing information regarding the second duration to each of the at least one user device of the second group, when executed individually or collectively by the at least one processor.

[0216] For example, when the above instructions are executed individually or collectively by the at least one processor, the base station may be caused to transmit an RRC setup message to each of the plurality of user devices in order to establish the RRC connection with the plurality of user devices. The RRC setup message may include information about the reference duration.

[0217] For example, the first duration may be set to be less than or equal to the maximum duration. The second duration may be set to be greater than or equal to the minimum duration.

[0218] For example, between the first user device among the at least one user device of the first group and the base station, if data is not transmitted or received during the first duration, the RRC connection between the first user device and the base station may be disconnected. Between the second user device among the at least one user device of the second group and the base station, if data is not transmitted or received during the second duration, the RRC connection between the second user device and the base station may be disconnected.

[0219] According to one embodiment, a method performed by a base station may include: identifying the number of user equipment (UE) devices to which a radio resource control (RRC) connection has been established; identifying at least one user device of a first group to which an emergency call service is provided among the user devices, based on the number of user devices exceeding a reference number; setting the duration of a timer for disconnecting the RRC connection to a first duration for each of the at least one user device of the first group; and setting the duration of a timer for disconnecting the RRC connection to a second duration shorter than the first duration for each of the at least one user device of a second group distinguished from the first group.

[0220] For example, the above method may include the operation of identifying one or more user devices among the plurality of user devices that are provided with a service distinct from the emergency call service, and the operation of identifying at least one user device of the second group among the one or more user devices in which the data drop rate is less than a reference drop rate.

[0221] For example, the above method may include the operation of identifying at least one user device of a third group among the one or more user devices, wherein the data drop rate is greater than or equal to the reference drop rate, and the operation of setting the duration of a timer for disconnecting an RRC connection to a third duration for the at least one user device of the third group.

[0222] For example, the third duration may correspond to the first duration.

[0223] For example, the above method may include an operation of determining the first duration based on increasing the reference duration for the plurality of user devices according to a specified ratio, and an operation of determining the second duration based on decreasing the reference duration according to the specified ratio.

[0224] For example, the above method may include the operation of increasing the first duration according to the specified ratio for each of the at least one user device of the first group and decreasing the second duration according to the specified ratio for each of the at least one user device of the second group until the number of the plurality of user devices is identified to be less than or equal to the reference number.

[0225] For example, the above method may include the operation of transmitting a first RRC reconstruction message containing information regarding the first duration to each of the at least one user device of the first group, and the operation of transmitting a second RRC reconstruction message containing information regarding the second duration to each of the at least one user device of the second group.

[0226] For example, the above method may include the operation of transmitting an RRC setup message to each of the plurality of user devices in order to establish an RRC connection with the plurality of user devices. The RRC setup message may include information about the reference duration.

[0227] For example, between the first user device among the at least one user device of the first group and the base station, if data is not transmitted or received during the first duration, the RRC connection between the first user device and the base station may be disconnected. Between the second user device among the at least one user device of the second group and the base station, if data is not transmitted or received during the second duration, the RRC connection between the second user device and the base station may be disconnected.

[0228] According to one embodiment, a non-transient computer-readable storage medium may store one or more programs. The one or more programs may include instructions that, when executed by at least one processor of a base station, cause the base station to identify the number of user equipment (UE) devices to which a radio resource control (RRC) connection has been established, identify at least one user equipment in a first group to which an emergency call service is provided among the multiple user equipment devices based on the number of multiple user equipment devices exceeding a reference number, set the duration of a timer for disconnecting the RRC connection to a first duration for each of the at least one user equipment in the first group, and set the duration of a timer for disconnecting the RRC connection to a second duration shorter than the first duration for each of the at least one user equipment in a second group distinct from the first group.

[0229] According to the embodiments described above, the base station can dynamically set the duration of the timer for disconnecting the RRC connection. For example, the base station can dynamically set the duration of the timer for disconnecting the RRC connection according to the number of user devices connected to the base station. As the duration of the timer for disconnecting the RRC connection is dynamically set, system resources and / or wireless resources can be used efficiently. In addition, since the base station can accommodate more user devices, the capacity of the system (or base station) can be increased.

[0230] According to the above-described embodiment, when the number of user devices connected to the base station exceeds a reference number, the base station can quickly disconnect the RRC connection of the user device by reducing the duration of the timer for disconnecting the RRC connection.

[0231] According to the above-described embodiment, if the number of user devices connected to the base station is less than a reference number, the base station may increase the duration of the timer for disconnecting the RRC connection. By increasing the duration of the timer for disconnecting the RRC connection, the base station may provide sufficient system resources and / or wireless resources to the user devices connected to the base station.

[0232] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0233] Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0234] When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of this disclosure. The one or more programs may be provided as a computer program product. The computer program product may be traded between a seller and a buyer as a product. The computer program product may be distributed in the form of a device-readable storage medium (e.g., compact disc read-only memory (CD-ROM)), or distributed online (e.g., download or upload) through an application store (e.g., Play Store™) or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product may be temporarily stored or temporarily created on a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or a relay server.

[0235] Such programs (software modules, software) may 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-ROM (CD-ROM), digital versatile discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0236] Additionally, the program may be stored on an attachable storage device that can be accessed via a communication network such as the Internet, Intranet, LAN (local area network), WAN (wide area network), or SAN (storage area network), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0237] In the specific embodiments of the present disclosure described above, the components included in the disclosure are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed of a singular form, and even if a component is expressed in the singular form, it may be composed of a plural form.

[0238] According to embodiments, one or more of the aforementioned components or operations may be omitted, or one or more other components or operations may be added. Generally or additionally, a plurality of components (e.g., modules or programs) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the plurality of components in the same or similar manner as those performed by the corresponding component among the plurality of components prior to integration. According to embodiments, operations performed by a module, program, or other component may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

[0239] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure.

Claims

In the case of a base station, Transmitter / Receiver; Memory comprising instructions and one or more storage media; and It includes at least one processor including a processing circuit, and When the above instructions are executed individually or collectively by the at least one processor, Identify the number of multiple user devices (user equipment, UE) to which a radio resource control (RRC) connection has been established, and Based on the number of the plurality of user devices exceeding a reference number, at least one user device of a first group among the plurality of user devices is provided with an emergency call service, and For each of the at least one user device of the first group, the duration of the timer for disconnecting the RRC connection is set to the first duration, and For each of at least one user device of a second group distinct from the first group, the base station causes the duration of a timer for disconnecting the RRC connection to be set to a second duration shorter than the first duration. Base station. In claim 1, when the instructions are executed individually or collectively by the at least one processor, Identify one or more user devices among the plurality of user devices above that provide a service distinct from the emergency call service, and Causing the base station to identify at least one user device of the second group among the above one or more user devices, wherein the data drop rate is less than the reference drop rate. Base station. In claim 2, when the instructions are executed individually or collectively by the at least one processor, Among the above one or more user devices, identify at least one user device of a third group in which the data drop rate is greater than or equal to the above standard drop rate, and For at least one user device of the third group above, causing the base station to set the duration of the timer for disconnecting the RRC connection to the third duration, Base station. In claim 3, the third duration is, Corresponding to the first duration above, Base station. In claim 1, when the instructions are executed individually or collectively by the at least one processor, Based on increasing the reference duration for the plurality of user devices according to a specified ratio, the first duration is determined, and Causing the base station to determine the second duration based on reducing the above reference duration according to the above specified ratio, Base station. In claim 5, when the instructions are executed individually or collectively by the at least one processor, Until the number of the above plurality of user devices is identified to be less than or equal to the above reference number: For each of the at least one user device of the first group, the first duration is increased according to the specified ratio, and For each of at least one user device of the second group above, causing the base station to reduce the second duration according to the specified ratio, Base station. In claim 5, when the instructions are executed individually or collectively by the at least one processor, A first RRC reconstruction message including information regarding the first duration is transmitted to each of the at least one user device of the first group, and Causing the base station to transmit a second RRC reconstruction message containing information regarding the second duration to each of the at least one user device of the second group, Base station. In claim 7, when the instructions are executed individually or collectively by the at least one processor, In order to establish the RRC connection with the plurality of user devices, the base station is caused to transmit an RRC setup message to each of the plurality of user devices, and The above RRC setup message is, including information on the above-mentioned standard duration, Base station. In claim 5, the first duration is, Set to less than the maximum duration, and The above second duration is, Set to be greater than or equal to the minimum duration, Base station. In claim 1, when data is not transmitted or received between the first user device among the at least one user device of the first group and the base station during the first duration, the RRC connection between the first user device and the base station is released, and Among the at least one user device of the second group, if data is not transmitted or received between the second user device and the base station during the second duration, the RRC connection between the second user device and the base station is released. Base station. In a method performed by a base station, An operation to identify the number of multiple user devices (user equipment, UE) for which an RRC (radio resource control) connection has been established; An operation to identify at least one user device of a first group among the plurality of user devices, which is provided with an emergency call service, based on the number of the plurality of user devices exceeding a reference number; For each of the at least one user device of the first group, the operation of setting the duration of a timer for disconnecting the RRC connection to a first duration; and For each of at least one user device of a second group distinguished from the first group, the operation of setting the duration of a timer for disconnecting the RRC connection to a second duration shorter than the first duration is included. method. In claim 11, the above method is, An operation to identify one or more user devices among the plurality of user devices above that are provided with a service distinct from the emergency call service; and Among the above one or more user devices, the operation of identifying at least one user device of the second group in which the data drop rate is less than a reference drop rate, method. In claim 12, the above method is, The operation of identifying at least one user device of a third group among the above one or more user devices, wherein the data drop rate is greater than or equal to the reference drop rate; and For at least one user device of the third group, the operation of setting the duration of a timer for disconnecting the RRC connection to a third duration, method. In claim 13, the third duration is, Corresponding to the first duration above, method. In a non-transient computer-readable storage medium storing one or more programs, said one or more programs, when executed by at least one processor of a base station, Identify the number of multiple user devices (user equipment, UE) to which a radio resource control (RRC) connection has been established, and Based on the number of the plurality of user devices exceeding a reference number, at least one user device of a first group among the plurality of user devices is provided with an emergency call service, and For each of the at least one user device of the first group, the duration of the timer for disconnecting the RRC connection is set to the first duration, and For each of at least one user device of a second group distinct from the first group, the method comprises instructions that cause the base station to set the duration of a timer for disconnecting an RRC connection to a second duration shorter than the first duration. Non-transient computer-readable storage media.

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