JP2019036873A - base station - Google Patents

Abstract

To realize efficient signaling on an interface between base stations in distributed communication.SOLUTION: A base station according to one embodiment of the present invention includes a wireless communication unit that performs wireless communication with a user device, a feedback unit that transmits feedback information on dual connectivity set for the user device to a base station that controls dual connectivity, and the feedback unit determines whether or not the feedback information is updated from feedback information to be compared at a transmission opportunity of the feedback information and transmits the feedback information only when the feedback information is updated.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a wireless communication system.

  At present, a new wireless communication system called NR (New Radio Access Technology) is being developed as a successor of LTE (Long Term Evolution) system and LTE-Advanced system in 3GPP (Third Generation Partnership Project). .

  In the NR system, similarly to dual connectivity in the LTE system, LTE divides data between a base station (eNB) of the LTE system and a base station (gNB) of the NR system, and transmits and receives data simultaneously by these base stations. The introduction of -NR dual connectivity (LTE-NR DC) or multi-RAT dual connectivity (MR DC) is under consideration. For example, in LTE-NR DC, as shown in FIG. 1, downlink data for a user equipment (UE) is transmitted between an LTE base station (eNB) and an NR base station (gNB) via an X2 interface or an Xn interface. And data are simultaneously transmitted from these base stations to the user equipment.

  In addition, as shown in FIG. 2, dual connectivity between base stations of the NR system is also considered. That is, the downlink data for the user equipment (UE) is distributed to a plurality of base stations (Distributed Unit: DU) via the F1 interface by the base station (Central Unit: CU) of the NR system, and from these base stations to the user equipment Data is transmitted simultaneously.

R3-172458 3GPP TS36.425 V14.0.0 (2017-03)

  Currently, in various distribution-type communications in which data is transmitted from a plurality of nodes to a user apparatus as described above, what kind of signal should be exchanged on the interface is discussed.

  An object of the present invention is to realize efficient signaling on an interface between base stations in distributed communication.

  In order to solve the above-described problem, an aspect of the present invention provides a wireless communication unit that performs wireless communication with a user apparatus, and a base that controls the dual connectivity with feedback information related to dual connectivity set for the user apparatus. A feedback unit that transmits to the station, wherein the feedback unit determines whether the feedback information is updated from the feedback information to be compared in the transmission opportunity of the feedback information, and the feedback information The present invention relates to a base station that transmits the feedback information only when it is updated.

  According to the present invention, it is possible to realize efficient signaling on an interface between base stations in distributed communication.

FIG. 1 is a schematic diagram illustrating LTE-NR dual connectivity. FIG. 2 is a schematic diagram showing inter-DU dual connectivity. FIG. 3 is a schematic diagram illustrating a wireless communication system according to an embodiment of the present invention. FIG. 4 is a block diagram showing a functional configuration of a base station according to an embodiment of the present invention. FIG. 5 is a flowchart showing feedback processing according to an embodiment of the present invention. FIG. 6 is a block diagram illustrating a hardware configuration of a base station and a user apparatus according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the following embodiments, distributed communication between base stations such as LTE-NR dual connectivity and DU dual connectivity, ie, a base station that supports dual connectivity is disclosed.

  In the conventional LTE dual connectivity, the transmission timing of a DDDS (Downlink Data Delivery Status) signal used as feedback information or control information for flow control is not stipulated in the specification, and various transmission timings are available depending on the implementation. Has been applied. In this case, since it is unclear at which timing information is transmitted, it has been difficult to optimize performance when interconnecting vendors. For this reason, in LTE-NR dual connectivity and CU-DU functional split, it is considered to specify the transmission timing of feedback information such as a DDDS signal or a control signal. For example, in R3-172458, three methods of Report polling, Report Periodically, and Report sending a number of PDUs are proposed as transmission triggers for the DDDS signal.

  However, in the transmission of the DDDS signal based on the proposed transmission trigger, the DDDS signal is transmitted even in the case where there is no change in the flow state particularly in the case of the transmission polling of the report polling and the report periodicity. The processing load on both base stations and the communication load on the interface will increase unnecessarily.

  For this reason, in the embodiment described later, when transmitting the data divided to the user apparatus in the dual connectivity, the base station provides feedback information in the latest transmission opportunity when the feedback information is transmitted in the feedback information such as the DDDS signal. The feedback information is transmitted to another base station in dual connectivity only when the feedback information is updated from the comparison target feedback information. Thereby, the same feedback information is repeatedly transmitted, and waste of processing resources of the base station and communication resources of the interface can be avoided.

  First, a radio communication system according to an embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic diagram illustrating a wireless communication system according to an embodiment of the present invention.

  As shown in FIG. 3, the user apparatus 200 is connected to and communicates with base stations 101 and 102 (hereinafter also referred to as the base station 100) of the LTE system and / or the NR system. And support dual connectivity. That is, the user apparatus 200 can simultaneously transmit or receive data divided with the base stations 101 and 102 by simultaneously using a plurality of component carriers provided by the base stations 101 and 102.

  For example, in LTE-NR dual connectivity, downlink data addressed to the user equipment 200 from a core network (not shown) is distributed between the base stations 101 and 102 via the X2 interface or the Xn interface. Each of 102 is transmitted to the user apparatus 200. In the inter-DU dual connectivity, downlink data addressed to the user apparatus 200 from the core network (not shown) is transmitted between the base stations 101 and 102 functioning as DUs via the F1 interface by the base station 100 functioning as CUs. And transmitted from each of the base stations 101 and 102 to the user apparatus 200. However, the embodiment of the present invention is not limited to the LTE-NR dual connectivity and the inter-DU dual connectivity as described above, but dual connectivity by a combination of these, dual connectivity using three or more nodes, 3GPP It can be applied to any appropriate distributed communication and dual connectivity including dual connectivity between a wireless communication system that complies with 3GPP and a wireless communication system that does not comply with 3GPP. For example, as dual connectivity or multi-connectivity using three or more nodes, distributed communication between an LTE base station (eNB) and NR base stations CU and DU may be included. Throughout this specification, the term dual connectivity also covers such distributed communication or multi-connectivity using three or more nodes.

  In the illustrated embodiment, the radio communication system 10 has only two base stations 101 and 102, but in general, a large number of base stations 100 are arranged to cover the service area of the radio communication system 10. The

  Next, a base station according to an embodiment of the present invention will be described with reference to FIG. The base station 100 according to the present embodiment transmits downlink data distributed by other base stations to the user apparatus 200, and also provides feedback information regarding downlink communication with the user apparatus 200 to the other base station at a predetermined transmission opportunity. Send to the station. For example, in LTE-NR dual connectivity, the base station 100 may be a secondary base station, and the other base stations may be master base stations. In the dual connectivity between DUs in the NR system, the base station 100 may be a DU and the other base stations may be CUs.

  FIG. 4 is a block diagram showing a functional configuration of a base station according to an embodiment of the present invention. As illustrated in FIG. 4, the base station 100 includes a radio communication unit 110 and a feedback unit 120.

  The wireless communication unit 110 performs wireless communication with the user device 200. Specifically, the radio communication unit 110 transmits various downlink signals such as a downlink control channel and a downlink data channel to the user apparatus 200, and various uplink signals such as an uplink control channel and an uplink data channel. Is received from the user apparatus 200. In addition, when dual connectivity is set for the user apparatus 200, the radio communication unit 110 transmits downlink data distributed in cooperation with other base stations to the user apparatus 200 at the same time.

  The feedback unit 120 transmits the feedback information regarding the dual connectivity set for the user apparatus 200 to the base station that controls the dual connectivity, and the feedback information is updated from the comparison target feedback information at the feedback information transmission opportunity. The feedback information is transmitted only when the feedback information is updated.

  Specifically, the feedback information indicates a transmission status of downlink data in dual connectivity communication with the user apparatus 200, and is not limited, and is a DDDS signal used for flow control of LTE-NR dual connectivity. It may be. For example, in LTE-NR dual connectivity, the feedback unit 120 transmits feedback information (for example, a DDDS signal) indicating downlink data transmission status in dual connectivity communication with the user apparatus 200 to a master base station that controls data distribution. To do. In the inter-DU dual connectivity, the feedback unit 120 transmits feedback information indicating the transmission status of the downlink data in the dual connectivity communication with the user apparatus 200 to the CU that controls data distribution.

  Further, when the feedback information transmission opportunity arrives, the feedback unit 120 confirms the transmission status of the downlink data in the dual connectivity communication with the user apparatus 200 at the arrived transmission opportunity, thereby obtaining the feedback information at the current transmission opportunity. The feedback information at the previous transmission opportunity is compared with the feedback information at the current transmission opportunity. Only when the previous feedback information and the current feedback information do not match, that is, only when the current feedback information is updated from the previous feedback information, the feedback unit 120 performs the current transmission opportunity at the incoming transmission opportunity. Is sent to the base station that controls data distribution. On the other hand, when the previous feedback information matches the current feedback information, that is, when the current feedback information is not updated from the previous feedback information, the feedback unit 120 avoids repeated transmission of the same feedback information. Therefore, the current feedback information is not transmitted at the arrival transmission opportunity. Thereby, the duplicate feedback information is not repeatedly transmitted, and waste of processing resources of the base station and communication resources of the interface can be avoided.

  The above-described determination of whether or not the current feedback information has been updated from the previous feedback information may be performed by comparing information elements included in the feedback information. Alternatively, the determination may be performed depending on whether new data transmission or new delivery confirmation is received from the previous transmission opportunity. Specifically, when there is no reception of new data transmission or new delivery confirmation from the previous transmission opportunity, the feedback unit 120 may determine that the feedback information has not been updated. When a new data transmission or a new delivery confirmation is received from the opportunity, the feedback unit 120 determines that the feedback information has been updated, and at the incoming transmission opportunity, receives a new data transmission or a new delivery confirmation. The current feedback information reflecting the reception may be transmitted.

  In one embodiment, the feedback unit 120 determines whether the feedback information is updated from the feedback information to be compared in the periodic transmission opportunity of the feedback information, and only when the feedback information is updated. May be sent. Here, the feedback information to be compared may be feedback information in a previous transmission opportunity in a periodic transmission opportunity of feedback information.

  As described above, it is considered that the DDDS signal is periodically transmitted using a timer or the like. In this case, according to the conventional technique, the same DDDS signal may be repeatedly transmitted at a periodic transmission opportunity. is there. In order to avoid such repeated transmission of the same feedback information, the feedback unit 120 transmits the downlink data in the dual connectivity communication with the user apparatus 200 at the transmission opportunity that arrives periodically. By confirming the above, feedback information on the current transmission opportunity is generated, and the feedback information on the previous periodic transmission opportunity is compared with the feedback information on the current transmission opportunity. Only when the previous feedback information does not match the current feedback information, that is, only when the current feedback information is updated from the previous feedback information, the feedback unit 120 receives the periodic transmission that has arrived. At this time, the current feedback information is transmitted to the base station that controls data distribution. On the other hand, when the previous feedback information matches the current feedback information, that is, when the current feedback information is not updated from the previous feedback information, the feedback unit 120 avoids repeated transmission of the same feedback information. Therefore, the current feedback information is not transmitted at the periodic transmission opportunity that has arrived. Thereby, it is possible to avoid the repeated feedback information being repeatedly transmitted over a plurality of periodic transmission opportunities.

  In one embodiment, the feedback unit 120 determines whether the feedback information is updated from the comparison target feedback information at the feedback information transmission opportunity in response to the feedback request, and only when the feedback information is updated. Feedback information may be transmitted. Here, the feedback information to be compared may be feedback information at the previous transmission opportunity of the feedback information in response to the feedback request.

  As described above, it is considered that the DDDS signal is transmitted in response to the polling request. In this case, according to the related art, the same DDDS signal may be repeatedly transmitted at the transmission opportunity in response to the polling request. is there. In order to avoid such repeated transmission of the same feedback information, the feedback unit 120 transmits downlink data in the dual connectivity communication with the user apparatus 200 at the transmission opportunity in response to the feedback request response. By confirming the situation, feedback information in the current transmission opportunity is generated, and the feedback information in the transmission opportunity for the response to the previous feedback request is compared with the feedback information in the current transmission opportunity. The feedback unit 120 responds to the current feedback request only when the previous feedback information and the current feedback information do not match, that is, only when the current feedback information is updated from the previous feedback information. The present feedback information is transmitted to the base station that controls the data distribution at the transmission opportunity for. On the other hand, when the previous feedback information matches the current feedback information, that is, when the current feedback information is not updated from the previous feedback information, the feedback unit 120 avoids repeated transmission of the same feedback information. Therefore, the current feedback information is not transmitted at the transmission opportunity for the response to the current feedback request. Thereby, it is possible to avoid that duplicate feedback information is repeatedly transmitted over transmission opportunities for responses of a plurality of feedback requests.

  Here, the embodiment related to the periodic transmission opportunity described above and the embodiment related to the transmission opportunity for responding to the feedback request may be combined. For example, in the embodiment related to the periodic transmission opportunity, the feedback information to be compared is the feedback information in the previous transmission opportunity in the periodic transmission opportunity of the feedback information, but the feedback request is not limited to this. The feedback information in the previous transmission opportunity of the feedback information in response to That is, the feedback unit 120 checks the transmission information of the current transmission opportunity by checking the transmission status of the downlink data in the dual connectivity communication with the user apparatus 200 at the transmission opportunity that arrives periodically. The feedback information in the transmission opportunity for the response of the latest feedback request is generated and the feedback information in the current transmission opportunity is compared. Only when the feedback information for the most recent feedback request response does not match the current feedback information, that is, when the current feedback information is updated from the feedback information for the most recent feedback request response. For example, the feedback unit 120 transmits the current feedback information to the base station that controls data distribution at the periodic transmission opportunity that has arrived. On the other hand, if the feedback information for the response of the most recent feedback request matches the current feedback information, that is, if the current feedback information has not been updated from the feedback information for the response of the most recent feedback request, the feedback The unit 120 may not transmit the current feedback information at the periodic transmission opportunity that has arrived in order to avoid repeated transmission of the same feedback information.

  On the other hand, in the embodiment related to the transmission opportunity for the response to the feedback request, the feedback information to be compared was the feedback information in the previous transmission opportunity of the feedback information in response to the feedback request, but is not limited thereto. The feedback information in the previous periodic transmission opportunity may be used. That is, the feedback unit 120 confirms the transmission status of the downlink data in the dual connectivity communication with the user apparatus 200 at the transmission opportunity for the response of the feedback request, thereby providing feedback information at the current transmission opportunity. And the feedback information in the previous periodic transmission opportunity is compared with the feedback information in the current transmission opportunity. Only when the feedback information at the previous periodic transmission opportunity and the current feedback information do not match, that is, only when the current feedback information is updated from the feedback information at the previous periodic transmission opportunity. The feedback unit 120 transmits the current feedback information to the base station that controls data distribution at a transmission opportunity for a response to the current feedback request. On the other hand, if the feedback information in the previous periodic transmission opportunity matches the current feedback information, that is, if the current feedback information has not been updated from the feedback information in the previous periodic transmission opportunity, the feedback unit 120. In order to avoid repeated transmission of the same feedback information, it is not necessary to transmit the current feedback information at the transmission opportunity for the response to the current feedback request.

  Next, feedback processing according to an embodiment of the present invention will be described with reference to FIG. FIG. 5 is a flowchart showing feedback processing according to an embodiment of the present invention.

  As shown in FIG. 5, the feedback processing transmits downlink data distributed by other base stations to the user apparatus 200 and feedback information related to downlink communication with the user apparatus 200 at a predetermined transmission opportunity. It is executed by the base station 100 that transmits to the other base station. For example, in LTE-NR dual connectivity, the base station 100 is a secondary base station, and the other base stations are master base stations. In the inter-DU dual connectivity in the NR system, the base station 100 is a DU and the other base stations are CUs.

  For example, the feedback processing may be started in response to the dual connectivity for the user device 200 being set.

  In step S101, the base station 100 determines whether a transmission opportunity or transmission timing of feedback information has arrived. In one example, when the transmission opportunity arrives periodically, the base station 100 starts a timer having a predetermined time interval by starting the feedback process, and determines that the transmission opportunity has arrived when the timer expires (S101). : YES), the process proceeds to step S102. In another example, when a transmission opportunity arrives in response to a feedback request, the base station 100 receives a feedback request from another base station or the like that controls the dual connectivity, and the transmission opportunity has arrived. Judgment is made (S101: YES), and the process proceeds to step S102.

  In step S102, the base station 100 generates feedback information indicating the transmission status of downlink data in the dual connectivity communication with the user apparatus 200 at the arrival transmission opportunity, and the generated feedback information and the feedback information at the latest transmission opportunity, etc. Compare with the feedback information of the comparison target. If the generated feedback information has been updated from the feedback information to be compared (S102: YES), the process proceeds to step S103. On the other hand, when the generated feedback information has not been updated from the feedback information to be compared (S102: NO), the process returns to step S101.

  In step S103, the base station 100 transmits the generated feedback information to another base station or the like that controls the dual connectivity. Upon receiving the feedback information, the master base station in the dual connectivity or another base station functioning as a CU executes flow control including redistribution of downlink data addressed to the user apparatus 200 based on the received feedback information. .

  In addition, the block diagram used for description of the said embodiment has shown the block of the functional unit. These functional blocks (components) are realized by any combination of hardware and / or software. Further, the means for realizing each functional block is not particularly limited. That is, each functional block may be realized by one device physically and / or logically coupled, and two or more devices physically and / or logically separated may be directly and / or indirectly. (For example, wired and / or wireless) and may be realized by these plural devices.

  For example, the user apparatus 200 and the base station 100 in an embodiment of the present invention may function as a computer that performs processing of the wireless communication method of the present invention. FIG. 6 is a block diagram illustrating a hardware configuration of the user apparatus 200 and the base station 100 according to an embodiment of the present invention. The above-described user apparatus 200 and base station 100 may be physically configured as a computer apparatus including a processor 1001, a memory 1002, a storage 1003, a communication apparatus 1004, an input apparatus 1005, an output apparatus 1006, a bus 1007, and the like. .

  In the following description, the term “apparatus” can be read as a circuit, a device, a unit, or the like. The hardware configurations of the user apparatus 200 and the base station 100 may be configured to include one or a plurality of the apparatuses illustrated in the figure, or may be configured not to include some apparatuses.

  Each function in the user apparatus 200 and the base station 100 is obtained by reading predetermined software (program) on hardware such as the processor 1001 and the memory 1002, so that the processor 1001 performs calculation, and communication by the communication apparatus 1004 or memory This is realized by controlling data reading and / or writing in the storage 1003 and the storage 1003.

  For example, the processor 1001 controls the entire computer by operating an operating system. The processor 1001 may be configured by a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic device, a register, and the like. For example, each component described above may be realized by the processor 1001.

  Further, the processor 1001 reads a program (program code), software module, and data from the storage 1003 and / or the communication device 1004 to the memory 1002, and executes various processes according to these. As the program, a program that causes a computer to execute at least a part of the operations described in the above embodiments is used. For example, processing by each component of the user apparatus 200 and the base station 100 may be realized by a control program stored in the memory 1002 and operated by the processor 1001, or may be realized similarly for other functional blocks. . Although the above-described various processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. Note that the program may be transmitted from a network via a telecommunication line.

  The memory 1002 is a computer-readable recording medium and includes, for example, at least one of ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), and the like. May be. The memory 1002 may be called a register, a cache, a main memory (main storage device), or the like. The memory 1002 can store a program (program code), a software module, and the like that can be executed to implement the wireless communication method according to the embodiment of the present invention.

  The storage 1003 is a computer-readable recording medium, such as an optical disc such as a CD-ROM (Compact Disc ROM), a hard disc drive, a flexible disc, a magneto-optical disc (eg, a compact disc, a digital versatile disc, a Blu-ray). (Registered trademark) disk, smart card, flash memory (for example, card, stick, key drive), floppy (registered trademark) disk, magnetic strip, and the like. The storage 1003 may be referred to as an auxiliary storage device. The storage medium described above may be, for example, a database, server, or other suitable medium including the memory 1002 and / or the storage 1003.

  The communication device 1004 is hardware (transmission / reception device) for performing communication between computers via a wired and / or wireless network, and is also referred to as a network device, a network controller, a network card, a communication module, or the like. For example, each of the above-described components may be realized by the communication device 1004.

  The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, or the like) that accepts an external input. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that performs output to the outside. The input device 1005 and the output device 1006 may have an integrated configuration (for example, a touch panel).

  Each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured with a single bus or may be configured with different buses between apparatuses.

  In addition, the user apparatus 200 and the base station 100 include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), and a field programmable gate array (FPGA). Hardware may be configured, and a part or all of each functional block may be realized by the hardware. For example, the processor 1001 may be implemented by at least one of these hardware.

  The notification of information is not limited to the aspect / embodiment described in the present specification, and may be performed by other methods. For example, information notification includes physical layer signaling (for example, DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (for example, RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling), It may be implemented by broadcast information (MIB (Master Information Block), SIB (System Information Block))), other signals, or a combination thereof. The RRC signaling may be referred to as an RRC message, and may be, for example, an RRC connection setup message, an RRC connection reconfiguration message, or the like.

  Each aspect / example described in this specification includes LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G, 5G, Future Radio Access (FRA), W-CDMA. (Registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, UWB (Ultra-WideBand), The present invention may be applied to a Bluetooth (registered trademark), a system using another appropriate system, and / or a next generation system extended based on the system.

  As long as there is no contradiction, the order of the processing procedures, sequences, flowcharts, and the like of each aspect / example described in this specification may be changed. For example, the methods described herein present the elements of the various steps in an exemplary order and are not limited to the specific order presented.

  The specific operation assumed to be performed by the base station 100 in this specification may be performed by its upper node in some cases. In a network composed of one or more network nodes having a base station, various operations performed for communication with a terminal may be performed by the base station and / or other network nodes other than the base station (e.g., Obviously, this can be done by MME or S-GW, but not limited to these. Although the case where there is one network node other than the base station in the above is illustrated, a combination of a plurality of other network nodes (for example, MME and S-GW) may be used.

  Information or the like can be output from the upper layer (or lower layer) to the lower layer (or upper layer). Input / output may be performed via a plurality of network nodes.

  Input / output information and the like may be stored in a specific location (for example, a memory) or may be managed by a management table. Input / output information and the like can be overwritten, updated, or additionally written. The output information or the like may be deleted. The input information or the like may be transmitted to another device.

  The determination may be performed by a value represented by 1 bit (0 or 1), may be performed by a true / false value (Boolean: true or false), or may be performed by comparing numerical values (for example, a predetermined value) Comparison with the value).

  Each aspect / example demonstrated in this specification may be used independently, may be used in combination, and may be switched and used with execution. In addition, notification of predetermined information (for example, notification of being “X”) is not limited to explicitly performed, but is performed implicitly (for example, notification of the predetermined information is not performed). Also good.

  Although the present invention has been described in detail above, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments described herein. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

  Software, whether it is called software, firmware, middleware, microcode, hardware description language, or other names, instructions, instruction sets, codes, code segments, program codes, programs, subprograms, software modules , Applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc. should be interpreted broadly.

  Also, software, instructions, etc. may be transmitted / received via a transmission medium. For example, software may use websites, servers, or other devices using wired technology such as coaxial cable, fiber optic cable, twisted pair and digital subscriber line (DSL) and / or wireless technology such as infrared, wireless and microwave. When transmitted from a remote source, these wired and / or wireless technologies are included within the definition of transmission media.

  Information, signals, etc. described herein may be represented using any of a variety of different technologies. For example, data, commands, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any of these May be represented by a combination of

  Note that the terms described in this specification and / or terms necessary for understanding this specification may be replaced with terms having the same or similar meaning. For example, the channel and / or symbol may be a signal. The signal may be a message. Further, the component carrier (CC) may be called a carrier frequency, a cell, or the like.

  As used herein, the terms “system” and “network” are used interchangeably.

  In addition, information, parameters, and the like described in this specification may be represented by absolute values, may be represented by relative values from a predetermined value, or may be represented by other corresponding information. . For example, the radio resource may be indicated by an index.

  The names used for the parameters described above are not limiting in any way. Further, mathematical formulas and the like that use these parameters may differ from those explicitly disclosed herein. Since various channels (eg, PUCCH, PDCCH, etc.) and information elements (eg, TPC, etc.) can be identified by any suitable name, the various names assigned to these various channels and information elements are However, it is not limited.

  A base station may accommodate one or more (eg, three) cells (also referred to as sectors). When the base station accommodates a plurality of cells, the entire coverage area of the base station can be divided into a plurality of smaller areas, and each smaller area can be divided into a base station subsystem (for example, an indoor small base station RRH: Remote). Communication service can also be provided by Radio Head). The term “cell” or “sector” refers to part or all of the coverage area of a base station and / or base station subsystem that provides communication services in this coverage. Further, the terms “base station”, “eNB”, “cell”, and “sector” may be used interchangeably herein. A base station may also be referred to in terms such as a fixed station, NodeB, eNodeB (eNB), access point, femtocell, small cell, and the like.

  A mobile station is defined by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless It may also be called terminal, remote terminal, handset, user agent, mobile client, client, or some other appropriate terminology.

  As used herein, the terms “determining” and “determining” may encompass a wide variety of actions. “Judgment”, “decision” can be, for example, calculating, computing, processing, deriving, investigating, looking up (eg, table, database or another (Searching in the data structure), and confirming (ascertaining) what has been confirmed may be considered as “determining” or “determining”. In addition, “determination” and “determination” include receiving (for example, receiving information), transmitting (for example, transmitting information), input (input), output (output), and access. (accessing) (e.g., accessing data in a memory) may be considered as "determined" or "determined". In addition, “determination” and “decision” means that “resolving”, “selecting”, “choosing”, “establishing”, and “comparing” are regarded as “determining” and “deciding”. May be included. In other words, “determination” and “determination” may include considering some operation as “determination” and “determination”.

  The terms “connected”, “coupled”, or any variation thereof, means any direct or indirect connection or coupling between two or more elements and It can include the presence of one or more intermediate elements between two “connected” or “coupled” elements. The coupling or connection between the elements may be physical, logical, or a combination thereof. As used herein, the two elements are radio frequency by using one or more wires, cables and / or printed electrical connections, and as some non-limiting and non-inclusive examples By using electromagnetic energy, such as electromagnetic energy having a wavelength in the region, microwave region, and light (both visible and invisible) region, it can be considered to be “connected” or “coupled” to each other.

  The reference signal may be abbreviated as RS (Reference Signal), and may be referred to as a pilot depending on an applied standard.

  As used herein, the phrase “based on” does not mean “based only on,” unless expressly specified otherwise. In other words, the phrase “based on” means both “based only on” and “based at least on.”

  Any reference to elements using the designations "first", "second", etc. as used herein does not generally limit the amount or order of those elements. These designations can be used herein as a convenient way to distinguish between two or more elements. Thus, a reference to the first and second elements does not mean that only two elements can be employed there, or that in some way the first element must precede the second element.

  The “means” in the configuration of each apparatus described above may be replaced with “unit”, “circuit”, “device”, and the like.

  These terms are similar to the term “comprising” as long as “including”, “including”, and variations thereof, are used herein or in the claims. It is intended to be comprehensive. Furthermore, the term “or” as used herein or in the claims is not intended to be an exclusive OR.

  A radio frame may be composed of one or more frames in the time domain. Each frame or frames in the time domain may be referred to as a subframe. A subframe may further be composed of one or more slots in the time domain. A slot may further be composed of one or more symbols (OFDM symbols, SC-FDMA symbols, etc.) in the time domain. Each of the radio frame, subframe, slot, and symbol represents a time unit for transmitting a signal. Radio frames, subframes, slots, and symbols may be called differently corresponding to each. For example, in the LTE system, the base station performs scheduling for allocating radio resources (frequency bandwidth, transmission power, etc. that can be used in each mobile station) to each mobile station. The minimum scheduling time unit may be referred to as TTI (Transmission Time Interval). For example, one subframe may be called a TTI, a plurality of consecutive subframes may be called a TTI, and one slot may be called a TTI. A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or a plurality of continuous subcarriers in the frequency domain. In the time domain of the resource block, one or a plurality of symbols may be included, and one slot, one subframe, or a length of 1 TTI may be included. One TTI and one subframe may each be composed of one or a plurality of resource blocks. The structure of the radio frame described above is merely an example, and the number of subframes included in the radio frame, the number of slots included in the subframe, the number of symbols and resource blocks included in the slots, and the subframes included in the resource block The number of carriers can be variously changed.

  As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the specific embodiment mentioned above, In the range of the summary of this invention described in the claim, various deformation | transformation・ Change is possible.

10 wireless communication system 100, 101, 102 base station 110 wireless communication unit 120 feedback unit 200 user apparatus

Claims (7)

A wireless communication unit that performs wireless communication with the user device;
A feedback unit that transmits feedback information about dual connectivity set for the user apparatus to a base station that controls the dual connectivity;
A base station having
The feedback unit determines whether or not the feedback information is updated from the feedback information to be compared at the transmission opportunity of the feedback information, and transmits the feedback information only when the feedback information is updated. Bureau.   The feedback unit determines whether the feedback information is updated from the feedback information to be compared in a periodic transmission opportunity of the feedback information, and the feedback information is only when the feedback information is updated. The base station according to claim 1, which transmits   The base station according to claim 2, wherein the comparison target feedback information is feedback information in a previous transmission opportunity in a periodic transmission opportunity of the feedback information.   The feedback unit determines whether the feedback information is updated from the feedback information to be compared in the transmission opportunity of the feedback information in response to a feedback request, and only when the feedback information is updated, The base station according to claim 1, which transmits feedback information.   The base station according to claim 4, wherein the comparison target feedback information is feedback information at a previous transmission opportunity of the feedback information in response to the feedback request.   The base station according to claim 1, wherein the feedback information indicates a downlink data transmission status.   7. The feedback unit according to claim 1, wherein the feedback unit determines that the feedback information is not updated when no new data transmission or new delivery confirmation is received from a transmission opportunity of the comparison target feedback information. A base station according to one item.

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