Method, user device, processor, program and communication system

Abstract

To provide a method and user equipment for appropriately controlling an operation related to a secondary cell.SOLUTION: In a mobile communication system, user equipment (UE) 100 comprises a transmission unit that transmits, to a network, information indicating a desired operation related to a secondary cell (SCell). The desired operation includes any one of a first operation to enable the secondary cell set to the user equipment, a second operation to disable the secondary cell set to the user equipment, and a third operation to set the secondary cell to the user equipment.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a method and a user equipment in a mobile communication system. [Background technology]

[0002] 3GPP (3rd Generation Partnership Project) (registered trademark, hereinafter the same), a standardization project for mobile communication systems, specifies communications in which a user device simultaneously uses multiple cells (a primary cell and at least one secondary cell). The case in which the multiple cells belong to the same base station is called carrier aggregation (CA). The case in which the multiple cells belong to two base stations is called dual connectivity (DC).

[0003] A user equipment configures a secondary cell (SCell) based on configuration information from a base station, and activates / deactivates the SCell in response to an instruction from the base station (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP Technical Specification "TS38.300 V16.0.0" January 2020 Summary of the Invention

[0005] A method according to a first aspect is a method executed in a user equipment (UE), the method including transmitting information indicating a desired operation regarding a secondary cell to a network, the desired operation including any one of a first operation of activating a secondary cell configured in the UE, a second operation of deactivating a secondary cell configured in the UE, and a third operation of configuring a secondary cell in the UE.

[0006] A method according to a second aspect is a method executed in a user equipment (UE) that includes receiving, from a network, information for intermittently activating a secondary cell configured in the UE, activating the secondary cell during an activation period determined based on the information, and deactivating the secondary cell during a period other than the activation period.

[0007] A method according to a third aspect is a method executed in a user equipment (UE) device, the method including: receiving, from a network, information for transitioning a primary secondary cell configured in the UE to a dormant state; and transitioning the primary secondary cell to the dormant state based on the information.

[0008] A user equipment according to a fourth aspect includes a transmitter configured to transmit information indicating a desired operation regarding a secondary cell to a network, the desired operation including any one of a first operation of activating a secondary cell configured in the user equipment, a second operation of deactivating the secondary cell configured in the user equipment, and a third operation of setting a secondary cell in the user equipment.

[0009] A user equipment according to a fifth aspect includes a receiving unit that receives information from a network for intermittently activating a secondary cell configured in the user equipment, and a control unit that activates the secondary cell during an activation period determined based on the information and deactivates the secondary cell during periods other than the activation period.

[0010] A user equipment according to a sixth aspect includes a receiving unit that receives information from a network to transition a primary secondary cell configured in the user equipment to a dormant state, and a control unit that transitions the primary secondary cell to the dormant state based on the information. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 1 is a diagram showing a configuration of a mobile communication system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the configuration of UE 100. As shown in FIG. [Figure 3] FIG. 3 is a diagram showing the configuration of base station 200. As shown in FIG. [Figure 4] FIG. 4 is a diagram showing the configuration of a protocol stack of a radio interface of a user plane. [Figure 5] FIG. 5 is a diagram showing the configuration of a protocol stack of the radio interface of the control plane. [Figure 6] FIG. 6 is a diagram illustrating an example of a DC. [Figure 7] FIG. 7 is a diagram illustrating the operation of the first operation example of the first embodiment. [Figure 8] FIG. 8 is a diagram illustrating the operation of the second operation example of the first embodiment. [Figure 9] FIG. 9 is a diagram illustrating the operation of the third operation example of the first embodiment. [Figure 10] FIG. 10 is a diagram showing the operation of intermittently enabling SCell according to the second embodiment. [Figure 11] FIG. 11 is a diagram illustrating the operation of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The current 3GPP specifications do not specify a method for a user equipment to notify a network of an operation related to the SCell that the user equipment desires (for example, an operation to activate the SCell). For example, if an application requiring high-throughput communication is suddenly started and the SCell configured in the user equipment is disabled, the user equipment cannot immediately activate the SCell.

[0013] Therefore, an object of the present disclosure is to appropriately control operations related to SCells.

[0014] A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0015] (Mobile communication system) First, a configuration of a mobile communication system according to an embodiment will be described. The mobile communication system according to an embodiment is a 3GPP 5G system, but LTE may be applied at least partially to the mobile communication system.

[0016] FIG. 1 is a diagram showing a configuration of a mobile communication system according to an embodiment.

[0017] As shown in FIG. 1, the mobile communication system includes a user equipment (UE) 100, a 5G radio access network (NG-RAN) 10, and a 5G core network (5GC) 20.

[0018] The UE 100 is a mobile device. The UE 100 may be any device that is used by a user. For example, the UE 100 is a mobile phone terminal (including a smartphone), a tablet terminal, a laptop PC, a communication module (including a communication card or a chipset), a sensor or a device provided in a sensor, a vehicle or a device provided in a vehicle (Vehicle UE), and / or an aircraft or a device provided in an aircraft (Aerial UE).

[0019] The NG-RAN 10 includes a base station (called a "gNB" in a 5G system) 200. The gNB 200 is sometimes called an NG-RAN node. The gNBs 200 are connected to each other via an Xn interface, which is an interface between base stations. The gNB 200 manages one or more cells. The gNB 200 performs wireless communication with a UE 100 that has established a connection with its own cell. The gNB 200 has a radio resource management (RRM) function, a routing function for user data (hereinafter simply referred to as "data"), a measurement control function for mobility control and scheduling, etc. The term "cell" is used to indicate the smallest unit of a wireless communication area. The term "cell" is also used to indicate a function or resource that performs wireless communication with a UE 100. One cell belongs to one carrier frequency.

[0020] The gNB may be connected to an Evolved Packet Core (EPC), which is an LTE core network, or the LTE base station may be connected to a 5GC. Also, the LTE base station and the gNB may be connected via an inter-base station interface.

[0021] The 5GC20 includes an Access and Mobility Management Function (AMF) and a User Plane Function (UPF) 300. The AMF performs various mobility controls for the UE 100. The AMF manages information about the area in which the UE 100 is located by communicating with the UE 100 using NAS (Non-Access Stratum) signaling. The UPF controls data forwarding. The AMF and UPF are connected to the gNB 200 via an NG interface, which is an interface between a base station and a core network.

[0022] FIG. 2 is a diagram showing a configuration of UE 100 (user equipment).

[0023] As shown in FIG. 2, the UE 100 includes a receiving unit 110, a transmitting unit 120, and a control unit .

[0024] The receiving unit 110 performs various types of reception under the control of the control unit 130. The receiving unit 110 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 130.

[0025] The transmitting unit 120 performs various transmissions under the control of the control unit 130. The transmitting unit 120 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmission signal) output by the control unit 130 into a radio signal and transmits it from the antenna.

[0026] The control unit 130 performs various controls in the UE 100. The control unit 130 includes at least one processor and at least one memory electrically connected to the processor. The memory stores programs executed by the processor and information used in processing by the processor. The processor may include a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation / demodulation and encoding / decoding of baseband signals. The CPU executes programs stored in the memory to perform various processes.

[0027] Figure 3 is a diagram showing the configuration of gNB200 (base station).

[0028] As shown in FIG. 3, the gNB 200 includes a transmitter 210, a receiver 220, a controller 230, and a backhaul communication unit 240.

[0029] The transmission unit 210 performs various transmissions under the control of the control unit 230. The transmission unit 210 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmission signal) output by the control unit 230 into a radio signal and transmits it from the antenna.

[0030] The receiving unit 220 performs various types of reception under the control of the control unit 230. The receiving unit 220 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 230.

[0031] The control unit 230 performs various controls in the gNB 200. The control unit 230 includes at least one processor and at least one memory electrically connected to the processor. The memory stores programs executed by the processor and information used in processing by the processor. The processor may include a baseband processor and a CPU. The baseband processor performs modulation / demodulation and encoding / decoding of baseband signals. The CPU executes programs stored in the memory to perform various processes.

[0032] The backhaul communication unit 240 is connected to neighboring base stations via an inter-base station interface. The backhaul communication unit 240 is connected to the AMF / UPF 300 via a base station-core network interface. Note that the gNB may be configured (i.e., functionally divided) with a CU (Central Unit) and a DU (Distributed Unit), and both units may be connected via an F1 interface.

[0033] FIG. 4 is a diagram showing the configuration of a protocol stack of a radio interface of a user plane that handles data.

[0034] As shown in Figure 4, the user plane radio interface protocol includes a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a service data adaptation protocol (SDAP) layer.

[0035] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the gNB 200 via a physical channel.

[0036] The PHY layer uses a frame structure including radio frames, subframes, slots, and symbols. A radio frame is made up of 10 subframes on the time axis. Each subframe has a length of 1 ms. Each subframe is made up of multiple slots. Each slot is made up of multiple symbols. Each subframe includes multiple resource blocks (RBs) on the frequency axis. Each resource block includes multiple subcarriers on the frequency axis. Of the radio resources (time-frequency resources) allocated to UE 100, frequency resources can be specified by resource blocks, and time resources can be specified by subframes (or slots, symbols).

[0037] In the downlink, the first few symbols of each subframe are used as a Physical Downlink Control Channel (PDCCH) for transmitting downlink control information, and the remaining part of each subframe is used as a Physical Downlink Shared Channel (PDSCH) for transmitting downlink data.

[0038] The MAC layer performs data priority control, retransmission processing using Hybrid ARQ (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of UE 100 and the MAC layer of gNB 200 via a transport channel. The MAC layer of gNB 200 includes a scheduler. The scheduler determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resource blocks to be allocated to UE 100.

[0039] The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the gNB 200 via logical channels.

[0040] The PDCP layer performs header compression / decompression and encryption / decryption.

[0041] The SDAP layer maps IP flows, which are the units for QoS control by the core network, to radio bearers, which are the units for QoS control by the AS (Access Stratum). Note that if the RAN is connected to the EPC, SDAP is not necessary.

[0042] FIG. 5 is a diagram showing the configuration of a protocol stack of a radio interface of a control plane that handles signaling (control signals).

[0043] As shown in FIG. 5, the protocol stack of the radio interface of the control plane has a Radio Resource Control (RRC) layer and a Non-Access Stratum (NAS) layer instead of the SDAP layer shown in FIG.

[0044] RRC signaling for various settings is transmitted between the RRC layer of UE100 and the RRC layer of gNB200. The RRC layer controls logical channels, transport channels, and physical channels according to the establishment, re-establishment, and release of radio bearers. When there is a connection (RRC connection) between the RRC of UE100 and the RRC of gNB200, UE100 is in an RRC connected state. When there is no connection (RRC connection) between the RRC of UE100 and the RRC of gNB200, UE100 is in an RRC idle state. When the RRC connection is suspended, UE100 is in an RRC inactive state.

[0045] The NAS layer, which is positioned above the RRC layer, performs session management, mobility management, etc. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the AMF 300.

[0046] The UE 100 has an application layer and the like in addition to the radio interface protocol.

[0047] (Carrier aggregation) Next, an overview of carrier aggregation (CA) will be explained.

[0048] In CA, a UE 100 having multiple transceivers is configured to use multiple cells managed by one base station 200. The multiple cells include one primary cell (PCell) and at least one secondary cell (SCell). At least downlink resources are configured for one SCell. Uplink resources may or may not be configured for one SCell.

[0049] UE 100 configures an SCell based on configuration information from base station 200. An index is assigned to each SCell configured in UE 100. The initial state of the SCell configured in UE 100 may be an activated state or a deactivated state.

[0050] The UE 100 activates / deactivates the SCell in response to an instruction from the base station 200.

[0051] Here, enabling an SCell means transitioning the SCell to an enabled state, and disabling an SCell means transitioning the SCell to a disabled state.

[0052] In an activated SCell, the UE 100 transmits a Sounding Reference Signal (SRS), measures and reports Channel State Information (CSI), monitors a PDCCH, and so on.

[0053] The CSI report includes a CQI (Channel Quality Information) report, a PMI (Precoding Matrix Indicator) report, an RI (Rank Indicator) report, etc. UE 100 measures a CSI-RS (Reference Signal) transmitted by base station 200, and determines the CQI, PMI, RI, etc. to report based on the measurement result. Base station 200 schedules UE 100 based on the CSI report received from UE 100 (for example, allocates downlink resources to UE 100, selects an MCS (Modulation and Coding Scheme), etc.).

[0054] In the disabled SCell, the UE 100 does not transmit a Sounding Reference Signal (SRS), measure and report CSI, or monitor a PDCCH.

[0055] (Dual Connectivity) Next, an overview of dual connectivity (DC) will be described. In the following, DC including NR access is mainly assumed. Such DC may be called MR-DC (Multi-RAT DC) or Multi-connectivity. Figure 6 is a diagram showing an example of DC.

[0056] As shown in Fig. 6, in DC, a UE 100 having multiple transceivers is configured to use resources provided by two different nodes (two different base stations). One base station provides NR access, and the other base station provides E-UTRA (LTE) or NR access. In the example of Fig. 6, base station 200A may be an eNB or a gNB, and base station 200B may be an eNB or a gNB.

[0057] One base station 200A functions as a master node (MN), and the other base station 200B functions as a secondary node (SN). The MN is a radio access node that provides a control plane connection to a core network. The MN may be called a master base station. The SN is a radio access node that does not have a control plane connection to a core network. The SN may be called a secondary base station.

[0058] The MN and SN are connected via a network interface (inter-base station interface), and at least the MN is connected to a core network. While Fig. 6 shows an example in which the inter-base station interface is an Xn interface, the inter-base station interface may also be an X2 interface. The MN and SN transmit and receive various types of information (described later) via the inter-base station interface.

[0059] A group of MN cells that are serving cells configured for the UE 100 is called a Master Cell Group (MCG). On the other hand, a group of SN cells that are serving cells configured for the UE 100 is called a Secondary Cell Group (SCG). A cell that belongs to an SCG is called an SCG Cell.

[0060] An SCG includes a primary SCG cell (PSCell) and zero or more SCells, that is, an SCG may include only PSCells.

[0061] A PUCCH (Physical Uplink Control Channel) resource is configured for the PSCell. UE 100 transmits a CSI report for some SCells that belong to the SCG on the PUCCH of the PSCell. UE 100 performs a Random Access (RA) procedure for the PSCell when an SCG is newly configured.

[0062] (First embodiment) Next, the operation of the mobile communication system according to the first embodiment will be described, assuming the configuration of the mobile communication system as described above.

[0063] The first embodiment relates to an embodiment in which UE100 transmits to base station 200 information indicating one of the following operations as a desired operation regarding the SCell: an operation to enable the SCell configured in UE100; an operation to disable the SCell configured in UE100; and an operation to configure the SCell in UE100.

[0064] Operation examples 1 to 3 of the first embodiment will be described below.

[0065] (Example 1) Operation example 1 is an operation example in which UE 100 transmits, to base station 200, information indicating an operation of activating an SCell configured in UE 100 or an operation of deactivating an SCell configured in UE 100 as a desired operation related to the SCell. Fig. 7 is a diagram showing the operation of operation example 1.

[0066] 7, in step S101, UE 100 establishes an RRC connection with base station 200 and is in an RRC connected state. Here, at least one disabled SCell is configured in UE 100 by base station 200, and UE 100 communicates with base station 200. The SCell is managed by base station 200. One or more enabled SCells may be configured in UE 100 by base station 200.

[0067] In step S102, the UE 100 determines a rate value (hereinafter referred to as a "required communication rate value") indicating a communication rate required by the UE 100. The communication rate may be a throughput or a data transmission rate.

[0068] The UE 100 may determine a value indicating a communication rate required by the UE 100 based on currently running applications. The UE 100 may determine the total value of communication rate values ​​required by each of the currently running applications as the required communication rate value. The UE 100 may determine the maximum value of communication rate values ​​required by each of the currently running applications as the required communication rate value. The UE 100 may determine the required communication rate value based on the CPU usage rate (or usage amount), memory usage rate (or usage amount), etc.

[0069] In step S103, UE 100 determines whether the required communication rate value is equal to or greater than a first threshold. UE 100 may set the first threshold based on threshold information received from base station 200. UE 100 may autonomously set the first threshold. For example, UE 100 may predict a maximum communication rate provided by a current serving cell based on the radio quality (RSRP, RSRQ, SINR, etc.) and bandwidth of the serving cell, and set the maximum communication rate as the first threshold. When UE 100 has multiple serving cells (enabled serving cells), UE 100 may predict the maximum communication rate of each of the multiple serving cells and set the sum of the maximum communication rates of the serving cells as the first threshold.

[0070] When the UE 100 determines that the required communication rate value is equal to or greater than the first threshold value (step S103: YES), the UE 100 advances the process to step S104.

[0071] In step S104, UE 100 transmits, as a desired operation regarding the SCell, information indicating an operation of activating the SCell configured in UE 100 (hereinafter referred to as "SCell activation desire information") to base station 200. This enables base station 200 to know that UE 100 desires activation of the SCell configured in UE 100.

[0072] The UE 100 may transmit the SCell activation request information in an RRC message (for example, a UE assist information message) or in a MAC CE.

[0073] The UE 100 may further transmit information indicating a required communication rate value together with the SCell activation request information, which allows the base station 200 to grasp the communication rate required by the UE 100 and to activate an SCell that can provide the communication rate.

[0074] UE 100 may further transmit a measurement report including the radio quality of the disabled SCell together with the SCell activation desire information, which enables base station 200 to identify an SCell with good radio quality and activate the SCell.

[0075] UE 100 may transmit SCell activation request information in a manner that allows identification of the SCell desired to be activated. This allows base station 200 to identify the SCell desired to be activated by UE 100. UE 100 may determine, based on the radio quality, bandwidth, etc. of each of the disabled SCells, an SCell that can provide a required communication rate as the SCell desired to be activated.

[0076] When transmitting the SCell activation request information in a manner that enables identification of the SCell desired to be activated, the UE 100 may transmit a cell identifier or an index of the SCell desired to be activated together with the SCell activation request information. The UE 100 may transmit the cell identifier or the index of the SCell desired to be activated as the SCell activation request information.

[0077] UE100 may generate a MAC CE including a field corresponding to each index of an SCell configured in UE100, set the value of the field corresponding to the index of the SCell desired to be enabled to "1", and transmit the MAC CE.

[0078] In step S105, the UE 100 receives, from the base station 200, an SCell activation instruction instructing the activation of one or more SCells.

[0079] In step S106, the UE 100 activates the one or more SCells in response to the SCell activation instruction.

[0080] In step S107, the UE 100 determines a required communication rate value in the same manner as in the process in step S102.

[0081] In step S108, the UE 100 determines whether the required communication rate value is less than a second threshold. The UE 100 may set the second threshold based on threshold information received from the base station 200. The UE 100 may also autonomously set the second threshold. The second threshold may be the same value as the first threshold in step S103.

[0082] When the UE 100 determines that the required communication rate value is less than the second threshold value (step S108: YES), the UE 100 advances the process to step S109.

[0083] In step S109, UE 100 transmits, as a desired operation regarding the SCell, information indicating an operation of disabling the SCell configured for UE 100 (hereinafter referred to as "SCell disabling desire information") to base station 200. This enables base station 200 to know that UE 100 desires to disable the SCell configured for UE 100.

[0084] The UE 100 may transmit the SCell disable request information in an RRC message (for example, a UE assist information message) or in a MAC CE.

[0085] The UE 100 may further transmit information indicating a required communication rate value together with the SCell deactivation request information. This allows the base station 200 to grasp the communication rate required by the UE 100, and to activate an SCell that can provide the communication rate while deactivating other SCells.

[0086] UE 100 may further transmit a measurement report including the radio quality of the enabled SCell together with the SCell deactivation request information, thereby enabling base station 200 to identify an SCell with poor radio quality and deactivate the SCell.

[0087] UE 100 may transmit SCell deactivation request information in a manner that enables identification of SCells for which deactivation is desired. In this way, base station 200 can identify SCells for which UE 100 desires to deactivate. UE 100 may determine SCells that can provide a required communication rate based on the radio quality and bandwidth of each of the enabled SCells, and may determine other SCells as SCells for which deactivation is desired.

[0088] When transmitting the SCell deactivation request information in a manner that enables identification of the SCell desired to be deactivated, the UE 100 may transmit a cell identifier or an index of the SCell desired to be deactivated together with the SCell deactivation request information. The UE 100 may transmit the cell identifier or the index of the SCell desired to be deactivated as the SCell deactivation request information.

[0089] UE100 may generate a MAC CE including a field corresponding to each index of an SCell configured in UE100, set the value of the field corresponding to the index of the SCell for which deactivation is desired to be performed to "0", and transmit the MAC CE.

[0090] In step S110, the UE 100 receives, from the base station 200, a SCell invalidation instruction instructing the invalidation of one or more SCells.

[0091] In step S111, the UE 100 disables the one or more SCells in response to the SCell disable instruction.

[0092] In operation example 1, UE 100 may omit the processes of steps S102 to S103 and / or steps S107 to S108. When the processes of steps S102 to S103 are omitted, UE 100 transmits SCell activation request information to base station 200 when SCell activation is required. When the processes of steps S107 to S108 are omitted, UE 100 transmits SCell deactivation request information to base station 200 when SCell deactivation is required.

[0093] In a first operation example, the UE 100 may transmit the SCell activation request information when a rate value indicating a communication rate required within a certain period of time in the future is equal to or greater than a first threshold. Alternatively, the UE 100 may transmit the SCell activation request information when an amount of transmission data to be generated within a certain period of time in the future is equal to or greater than a first data amount. The certain period is expressed in the number of milliseconds or the number of subframes. The certain period is set by the base station 200. The first data amount is set by the base station 200.

[0094] In the first operation example, when a rate value indicating a communication rate required within a certain period in the future is equal to or greater than a first threshold, or when the amount of transmission data to be generated within a certain period in the future is equal to or greater than a predetermined value, the UE 100 may transmit a notification of large-volume data communication prediction to the base station 200 instead of the SCell activation request information. Upon receiving the notification of large-volume data communication prediction from the UE 100, the base station 200 may consider that the UE 100 desires to activate the SCell configured for the UE 100, and may transmit an SCell activation instruction to the UE 100.

[0095] In the first operation example, the UE 100 may transmit the SCell invalidation request information when a rate value indicating a communication rate required within a certain period of time in the future is less than a second threshold. Alternatively, the UE 100 may transmit the SCell invalidation request information when the amount of transmission data to be generated within a certain period of time in the future is less than a second data amount. The second data amount is set by the base station 200.

[0096] In the first operation example, when a rate value indicating a communication rate required within a certain period in the future is less than a second threshold, or when the amount of transmission data to be generated within a certain period in the future is less than a second data amount, UE 100 may transmit a notification of small amount of data communication prediction to base station 200 instead of SCell deactivation request information. Upon receiving the notification of small amount of data communication prediction from UE 100, base station 200 may consider that UE 100 desires to deactivate the SCell configured for UE 100, and may transmit an SCell deactivation instruction to UE 100.

[0097] In the first operation example, the thresholds (first threshold, second threshold, first data amount, second data amount) may be set separately for uplink communication and downlink communication. The UE 100 determines the required communication rate value and / or the amount of transmission data separately for uplink communication and downlink communication, and compares them with the corresponding thresholds.

[0098] For example, when the required communication rate value of uplink communication is equal to or greater than a first threshold set for uplink communication, UE 100 transmits information indicating an operation to activate an SCell to which uplink resources are configured as a desired operation for the SCell. When the required communication rate value of uplink communication is less than a second threshold set for uplink communication, UE 100 transmits information indicating an operation to deactivate an SCell to which uplink resources are configured as a desired operation for the SCell.

[0099] (Example 2) The following describes Operation Example 2, focusing mainly on differences from Operation Example 1. Operation Example 2 is an operation example relating to transmitting, as a desired operation related to an SCell, information indicating an operation of activating an SCG Cell set in UE 100 or an operation of deactivating an SCG Cell set in UE 100. Fig. 8 is a diagram illustrating the operation of Operation Example 2.

[0100] As shown in FIG. 8, in step S201, the UE 100 establishes an RRC connection with the base station 200A and is in an RRC connected state.

[0101] In step S202, the UE 100 starts DC communication with the base station 200A and the base station 200B. Here, at least one disabled SCG cell is configured in the UE 100. The base station 200A functions as the MN of the UE 100, and the base station 200B functions as the SN of the UE 100.

[0102] The processing in steps S203 and S204 is the same as that in steps S102 and S103.

[0103] In step S205, the UE 100 transmits, as a desired operation for the SCell, information indicating an operation of activating an SCG Cell set in the UE 100 (hereinafter referred to as "SCG Cell activation desired information") to the base station 200A or the base station 200B.

[0104] As in step S104, in step S205, UE 100 may further transmit information indicating a required communication rate value together with the SCG cell activation request information. UE 100 may further transmit a measurement report including radio quality for the disabled SCG cell together with the SCG cell activation request information. UE 100 may transmit the SCG cell activation request information in a manner that allows identification of the SCG cell for which activation is requested.

[0105] When transmitting the SCG Cell activation request information to the base station 200A, the UE 100 transmits the SCG Cell activation request information in an RRC message (for example, a UE assist information message). In this case, the base station 200A transfers the SCG Cell activation request information to the base station 200B.

[0106] When transmitting the SCG Cell activation request information to the base station 200B, the UE 100 may transmit the SCG Cell activation request information by an RRC message via an SRB3 or by a MAC CE. The SRB3 refers to a control radio bearer established between the UE 100 and the SN. The UE 100 may generate a MAC CE including a field corresponding to each index of an SCG Cell set in the UE 100, set the value of the field corresponding to the index of the SCG Cell desired to be activated to "1", and transmit the MAC CE.

[0107] In step S206, the UE 100 receives an SCG cell activation instruction instructing the activation of one or more SCG cells from the base station 200A or the base station 200B. When the UE 100 receives the SCG cell activation instruction from the base station 200A, the SCG cell activation instruction is transmitted from the base station 200B to the base station 200A and then transmitted to the UE 100.

[0108] In step S207, the UE 100 activates the one or more SCG cells in response to the SCG cell activation instruction.

[0109] The processing in steps S208 and S209 is the same as that in steps S107 and S108.

[0110] In step S210, the UE 100 transmits, as a desired operation for the SCell, information indicating an operation to disable the SCG Cell configured in the UE 100 (hereinafter referred to as "SCG Cell disablement request information") to the base station 200A or the base station 200B. As a result, the base station 200A or the base station 200B knows that the UE 100 desires to disable the SCG Cell configured in the UE 100.

[0111] As in step S109, in step S210, UE 100 may further transmit information indicating a required communication rate value together with the SCG cell deactivation request information. UE 100 may further transmit a measurement report including radio quality for an activated SCG cell together with the SCG cell deactivation request information. UE 100 may transmit the SCG cell deactivation request information in a manner that allows identification of the SCG cell desired to be deactivated.

[0112] When transmitting the SCG Cell deactivation request information to the base station 200A, the UE 100 transmits the SCG Cell deactivation request information in an RRC message (for example, a UE assist information message). In this case, the base station 200A transfers the SCG Cell deactivation request information to the base station 200B.

[0113] When transmitting the SCG Cell deactivation request information to base station 200B, UE 100 may transmit the SCG Cell deactivation request information by an RRC message via SRB 3 or by a MAC CE. UE 100 may generate a MAC CE including a field corresponding to each index of an SCG Cell configured in UE 100, set the value of the field corresponding to the index of the SCG Cell desired to be deactivated to "0", and transmit the MAC CE.

[0114] In step S211, the UE 100 receives an SCG Cell deactivation instruction instructing the deactivation of one or more SCG Cells from the base station 200A or the base station 200B. When the UE 100 receives the SCG Cell deactivation instruction from the base station 200A, the SCG Cell deactivation instruction is transmitted from the base station 200B to the base station 200A and then transmitted to the UE 100.

[0115] In step S212, the UE 100 disables the one or more SCG cells in response to the SCG cell disable instruction.

[0116] In the second operation example, the UE 100 may transmit, as the SCG cell activation request information, information indicating a request to activate the SCG (that is, to activate all the cells belonging to the SCG).

[0117] In the second operation example, the UE 100 may transmit, as the SCG Cell deactivation request information, information indicating a desire to deactivate the SCG (that is, to deactivate all cells belonging to the SCG).

[0118] (Example 3) The following describes the operation example 3, focusing mainly on differences from the operation example 1. The operation example 3 is an operation example related to transmitting, as a desired operation related to the SCell, information indicating an operation of setting the SCell in the UE 100. Fig. 9 is a diagram showing the operation of the operation example 3.

[0119] 9, in step S301, the UE 100 establishes an RRC connection with the base station 200 and is in an RRC connected mode. The UE 100 does not have an SCell (i.e., neither CA nor DC is configured), and performs radio communication with the base station 200 via only one serving cell.

[0120] The processing in steps S302 and S303 is the same as that in steps S102 and S103.

[0121] In step S304, UE 100 transmits information indicating that it desires an operation to configure an SCell in UE 100 (i.e., an operation to configure CA in UE 100) as a desired operation related to the SCell (hereinafter referred to as "SCell configuration desire information") to base station 200. As a result, base station 200 knows that UE 100 desires to configure an SCell in UE 100.

[0122] The UE 100 may transmit the SCell configuration preference information in an RRC message (for example, a UE assist information message) or in a MAC CE.

[0123] The UE 100 may transmit a candidate cell list including cell identifiers of candidate cells together with the SCell configuration preference information. The candidate cell list may include information indicating the radio quality of each candidate cell. The UE 100 may determine a cell having quality that satisfies a predetermined quality standard (S-criteria or R-criteria) as a candidate cell. This allows the base station 200 to configure a cell with good radio quality for the UE 100 as an SCell based on the candidate cell list.

[0124] The UE 100 may further transmit information indicating the required communication rate value together with the SCell configuration preference information, thereby enabling the base station 200 to configure, for the UE 100, a cell that can provide the communication rate indicated by the required communication rate value as the SCell.

[0125] When UE 100 supports DC, UE 100 may transmit information indicating that it desires an operation of setting an SCG in UE 100 (i.e., setting DC in UE 100) as a desired operation for SCell (hereinafter referred to as "SCG setting desire information") to base station 200. In this way, base station 200 knows that UE 100 desires to set an SCG in UE 100.

[0126] The UE 100 may transmit information indicating the candidate cell list and / or the required communication rate value together with the SCG configuration preference information. Based on this information, the base station 200 can configure an appropriate cell for the UE 100 as a PSCell (and an SCell belonging to the SCG).

[0127] In step S305, the UE 100 receives an instruction to configure an SCell or an SCG from the base station 200.

[0128] In step S306, the UE 100 configures the SCell or the SCG in accordance with the instruction.

[0129] (Second embodiment) Next, an operation according to the second embodiment will be described. The second embodiment relates to intermittently activating an SCell configured in the UE 100. By intermittently activating the SCell, it is possible to save power in the UE 100.

[0130] The operation of intermittent activation of the SCell will now be described with reference to Fig. 10, which is a diagram showing the operation of intermittent activation of the SCell.

[0131] As shown in Fig. 10, UE 100 performs an intermittent activation operation on the configured SCell. Specifically, UE 100 activates the SCell at activation start timings (t1, t2, t3, ...) that occur every cycle (T). UE 100 continuously activates the SCell during an activation period within one cycle (T). UE 100 deactivates the SCell during periods other than the activation period within one cycle (T).

[0132] During a predetermined period immediately before the activation start timing, UE 100 may measure and report CSI regarding the SCell while maintaining the SCell disabled. As a result, immediately after the SCell is activated, base station 200 that manages the SCell can schedule UE 100 (for example, allocate downlink resources to UE 100, select an MCS, etc.).

[0133] During a predetermined period immediately before the activation start timing, UE 100 may transmit SRS on the SCell while maintaining the SCell disabled. As a result, immediately after the SCell is enabled, base station 200 that manages the SCell can grasp the uplink channel quality of UE 100 and allocate appropriate uplink resources to UE 100. When UE 100 does not perform uplink transmission, it does not need to transmit SRS.

[0134] The above-mentioned activation start timing, cycle (T), activation period, and predetermined period are configured in UE 100 by base station 200. Radio resources for measuring and reporting CSI during the predetermined period (hereinafter referred to as "radio resources for CSI") are configured by base station 200. The radio resources for CSI include radio resources for transmitting CSI-RS, radio resources for transmitting CSI reports, etc.

[0135] The validation start timing may be expressed by a radio frame number and a subframe number, or may be expressed by a slot number and a symbol number in addition to the radio frame number and the subframe number.

[0136] The period (T), activation period, and predetermined period are expressed in number of milliseconds or number of subframes.

[0137] The activation period may be dynamically extended. For example, when the UE 100 receives downlink user data or transmits uplink data during the activation period, the UE 100 starts a timer. While the timer is running, the UE 100 continuously activates the SCell. That is, the activation period is extended until the timer expires. The value of the timer is set by the base station 200.

[0138] For example, the UE 100 starts the timer in the validation period when receiving a PDCCH addressed to the UE 100. The UE 100 may start the timer in the validation period when transmitting a scheduling request (SR) and / or a buffer status report (BSR).

[0139] When the UE 100 performs DC with the base station 200A (MN) and the base station 200B (SN), the intermittent activation operation may be applied to the SCG Cell. The intermittent activation operation may be applied to the PSCell in the SCG Cell.

[0140] In the second embodiment, UE 100 receives information for configuring the intermittent activation operation of SCell (hereinafter referred to as "intermittent activation setting information") from base station 200, and performs the above-mentioned intermittent activation operation of SCell based on the intermittent activation setting information. The intermittent activation setting information includes identification information of the SCell that is the target of intermittent activation (SCell identifier or index), and information indicating parameters related to the intermittent activation operation (activation start timing, period (T), activation period, predetermined period, and timer value).

[0141] When the discontinuous activation operation is applied to an SCG Cell, the discontinuous activation setting information may be transmitted from the base station 200A to the UE 100 and the base station 200B. The discontinuous activation setting information may be transmitted from the base station 200B to the UE 100 via the SRB3. The UE 100 may transmit the discontinuous activation setting information received from the base station 200B to the base station 200A.

[0142] (Third embodiment) Next, an operation according to the third embodiment will be described. The third embodiment relates to transitioning a PSCell configured in the UE 100 to a dormant state. By transitioning the PSCell to a dormant state, it is possible to save power in the UE 100.

[0143] The UE 100 does not monitor the PDCCH on the PSCell in the dormant state, but may measure the CSI for the PSCell. The UE 100 may perform AGC (Automatic Gain Control) and beam management (beam measurement and selection, beam failure recovery, etc.) for the dormant PSCell.

[0144] FIG. 11 is a diagram illustrating the operation of the third embodiment.

[0145] As shown in FIG. 11, in step S401, the UE 100 establishes an RRC connection with the base station 200A and is in an RRC connected state.

[0146] In step S402, the UE 100 starts DC communication with the base station 200A and the base station 200B.

[0147] In step S403, the base station 200A transmits, to the UE 100, PSCell dormancy setting information for transitioning the PSCell to a dormant state, by an RRC message or a MAC CE.

[0148] The PSCell dormancy setting information includes information for determining the timing at which the PSCell transitions to a dormant state (hereinafter referred to as "dormancy timing"). The UE 100 determines the dormancy timing based on the PSCell dormancy setting information.

[0149] For example, the PSCell dormancy setting information includes a timer value, and the UE 100 starts a timer corresponding to the timer value in response to receiving the PSCell dormancy setting information, and determines the timing of timer expiration as the dormancy timing. That is, the UE 100 transitions the PSCell to a dormant state at the timing of timer expiration. Alternatively, the PSCell dormancy setting information may simply be an instruction to transition the PSCell to a dormant state, and the UE 100 may determine the timing of receiving such an instruction as the dormancy timing.

[0150] The PSCell dormancy setting information is also transmitted from the UE 100 or the base station 200A to the base station 200B. The base station 200B determines the dormancy timing based on the PSCell dormancy setting information and stops transmission of the PDCCH to the UE 100.

[0151] In step S404, the UE 100 transitions the PSCell to a dormant state at the dormant timing.

[0152] In step S405, the UE 100 performs CSI measurement for the PSCell in the dormant state and transmits a CSI report about the CSI measurement to the base station 200A. Here, the UE 100 may periodically measure and report the CSI. In this case, the periodicity is set by the base station 200A.

[0153] In step S406, the base station 200A transmits, to the UE 100, PSCell activation setting information for activating the PSCell by using an RRC message or a MAC CE.

[0154] The PSCell activation configuration information includes information for determining the timing to activate the PSCell (hereinafter referred to as "activation timing"). The UE 100 determines the activation timing based on the PSCell activation configuration information. The PSCell activation configuration information is also transmitted from the base station 200A to the base station 200B.

[0155] In step S408, the UE 100 activates the PSCell at the activation timing.

[0156] After transmitting the PSCell activation configuration information and before the activation timing, in step S407, the base station 200B receives a CSI report of the PSCell from the UE 100 or the base station 200A. This allows the base station 200B to schedule the UE 100 immediately after the PSCell is activated.

[0157] If the period from the timing at which the base station 200B receives the PSCell activation configuration information to the activation timing is shorter than the allowable delay on the base station interface between the base station 200A and the base station 200B, the CSI report transmitted from the base station 200A may not reach the base station 200B before the activation timing arrives. In this case, the base station 200B receives the CSI report from the UE 100 in step S407.

[0158] (Other embodiments) A program may be provided that causes a computer to execute each process performed by the UE 100 and the base station 200 (base station 200A, base station 200B). The program may be recorded on a computer-readable medium. Using the computer-readable medium, the program can be installed on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM.

[0159] In addition, circuits that execute each process performed by UE100 and base station 200 (base station 200A, base station 200B) may be integrated, and at least a portion of UE100 and base station 200 (base station 200A, base station 200B) may be configured as a semiconductor integrated circuit (chip set, SoC).

[0160] The above describes the embodiments in detail with reference to the drawings, but the specific configuration is not limited to that described above, and various design changes can be made within the scope that does not deviate from the gist of the invention.

[0161] This application claims priority from Japanese Patent Application No. 2020-091386 (filed May 26, 2020), the entire contents of which are incorporated herein by reference.

Claims

1. Using a dual connectivity scheme, the device is connected to a master node associated with a master cell group and also to a secondary node associated with a secondary cell group.

1. A method performed in a user device, comprising: sending an RRC message to the master node indicating a preference for deactivation of the secondary cell group; receiving information from the master node instructing the deactivation of the secondary cell group; In response to receiving the information, the SCG cell belonging to the secondary cell group performs control not to transmit a Sounding Reference Signal (SRS), report Channel State Information (CSI), and monitor a PDCCH. method.

2. A user equipment (UE) that is connected to a master node associated with a master cell group and to a secondary node associated with a secondary cell group using a dual connectivity scheme, a transmitter configured to transmit an RRC message to the master node indicating a preference for deactivation of the secondary cell group; a receiving unit that receives information instructing the disablement of the secondary cell group from the master node; and a control unit that controls not to transmit a Sounding Reference Signal (SRS), report Channel State Information (CSI), and monitor a PDCCH in an SCG cell that belongs to the secondary cell group in response to receiving the information. User equipment.

3. A processor for controlling a user equipment connected to a master node associated with a master cell group and connected to a secondary node associated with a secondary cell group using a dual connectivity scheme, comprising: sending an RRC message to the master node indicating a preference for deactivation of the secondary cell group; A process of receiving information instructing the deactivation of the secondary cell group from the master node; In response to receiving the information, a process of controlling transmission of a Sounding Reference Signal (SRS), reporting of Channel State Information (CSI), and monitoring of a PDCCH in an SCG cell belonging to the secondary cell group is executed. Processor.

4. A program for controlling a user equipment connected to a master node associated with a master cell group and connected to a secondary node associated with a secondary cell group using a dual connectivity method, comprising: sending an RRC message to the master node indicating a preference for deactivation of the secondary cell group; A process of receiving information instructing the deactivation of the secondary cell group from the master node; In response to receiving the information, the user equipment is caused to perform a process of controlling transmission of a Sounding Reference Signal (SRS) in an SCG cell belonging to the secondary cell group, reporting of Channel State Information (CSI), and not monitoring a PDCCH. program.

5. A communication system comprising the user equipment according to claim 2, a master node, and a secondary node.

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