JP6564635B2 - User apparatus, radio communication system and communication method - Google Patents

Description

  The present invention relates to a user apparatus, a wireless communication system, and a communication method.

  In an LTE (Long Term Evolution) system, a base station communicates with each user apparatus via a cell. In addition, the base station assigns a different identifier (C-RNTI: Cell-Radio Network Temporary Identifier) for each user apparatus and communicates with the user apparatus using the identifier, to which user apparatus the data to be transmitted and received is assigned. Whether the data is data is identified (for example, see Non-Patent Document 1).

  Moreover, the base station allocates radio resources used for transmission / reception of downlink data and uplink data using the C-RNTI allocated to the user apparatus UE.

  For example, although DCI (Downlink Control Information) for each user apparatus is included in PDCCH (Physical Downlink Control Channel), CRC (Cyclic Redundancy Check) included in each DCI is C-RNTI of each user apparatus. Are each masked. Further, the user apparatus makes a determination using the C-RNTI assigned to the CRC included in each DCI, and when correctly determined, determines that the DCI is a DCI for itself, If it cannot be determined correctly, it is determined that the DCI is for other user apparatuses.

  Next, the LTE system employs carrier aggregation (CA) that performs communication using a plurality of carriers simultaneously with a predetermined bandwidth (maximum 20 MHz) as a basic unit. A carrier that is a basic unit in carrier aggregation is called a component carrier (CC).

  When CA is performed, a PCell (Primary Cell) that is a reliable cell that secures connectivity and a SCell (Secondary Cell) that is an ancillary cell are provided to the user equipment. Is set. First, the user apparatus can connect to the PCell and add an SCell as necessary.

  The SCell is a cell that is added to the PCell and set for the user apparatus. The addition and deletion of the SCell is performed by RRC (Radio Resource Control) signaling. The SCell is a cell that can be communicated (scheduled) for the first time after being activated because it is in an inactive state (deactivated state) immediately after being set for the user apparatus.

  In CA up to 3GPP (3rd Generation Partnership Project) Rel-12, a maximum data rate is realized by bundling up to five CCs to increase the bandwidth.

3GPP TS36.300 V12.5.0 (2015-03)

  C-RNTI is an identifier assigned to be unique within a cell, but the specific assignment method depends on the implementation of the base station.

  FIG. 1 is a diagram for explaining a C-RNTI allocation method in conventional LTE. In FIG. 1, it is assumed that the base station configures cell A and cell B. Further, it is assumed that the user apparatus #X exists in the cell A and the user apparatus #Y exists in the cell B. FIG. 1A shows a method of assigning C-RNTI in cell units. That is, the base station assigns the C-RNTI to the user apparatus so that the C-RNTI is unique within each cell. On the other hand, FIG.1 (b) has shown the method of allocating C-RNTI per base station. That is, the base station assigns the C-RNTI to the user apparatus so that the C-RNTI is unique within the base station.

  In the case of FIG. 1 (a), since the C-RNTI needs to be unique within each cell, the base station can assign the same C-RNTI to the user equipment #X and the user equipment #Y. It is. On the other hand, in the case of FIG. 1B, the base station needs to assign different C-RNTIs to the user equipment #X and the user equipment #Y.

  In the future, when services such as MTC (Machine Type Communication) are widely realized, it is assumed that many user apparatuses are simultaneously connected to the base station. In the method of allocating C-RNTI in units of base stations, the number of user apparatuses that can be simultaneously connected to one base station is limited to the number of C-RNTIs (about 65,000). On the other hand, in the method of allocating C-RNTI in units of cells, the number of user apparatuses that can be connected to one base station simultaneously can be increased to the number of C-RNTIs × the number of cells. Therefore, in the future, it is assumed that a method of allocating C-RNTI in units of cells will be used more than a method of allocating C-RNTI in units of base stations.

  Next, 3GPP Rel. In 13 LTE, in order to realize more flexible and high-speed wireless communication, and to allow a large number of CCs to be bundled in a continuous ultra-wideband unlicensed band, a maximum of 5 CCs bundled in CA is limited. CA enhancement to be taken is being considered. For example, a CA that bundles up to 32 CCs has been studied. As an example, FIG. 2 shows an example of bundling 16CC.

  Here, in LTE, it is prescribed | regulated that the same C-RNTI is allocated with respect to PCell and SCell set to a user apparatus. Then, when many SCells are set in the user apparatus, it may be difficult to secure on the SCell side the same C-RNTI as the C-RNTI used on the PCell side.

  This will be described more specifically with reference to FIG. In FIG. 1A, it is assumed that the cover areas of cell A and cell B overlap. The base station tries to add a cell B (SCell) to the user apparatus #X located in the cell A (PCell). In this case, the user equipment #X needs to use C-RNTI # 1 also in the cell B. However, since C-RNTI # 1 is assigned to user equipment #Y in cell B, user equipment #X cannot add cell B.

  On the other hand, in order to avoid such a state, the base station causes the user apparatus to execute Intra-cell HO (handover), so that the C-RNTI allocated to the user apparatus #X is not used. It is possible to change to RNTI (for example, C-RNTI # 2). However, when Intra-cell HO is performed, communication of user data is interrupted between the base station and the user apparatus during the HO process, resulting in a deterioration in throughput.

  The disclosed technique has been made in view of the above, and an object thereof is to provide a technique capable of assigning a C-RNTI different from that of the primary cell to the secondary cell.

A user apparatus of the disclosed technology is a user apparatus that communicates with a base station in a wireless communication system that supports carrier aggregation, and receives a cell temporary identifier in a primary cell and a cell temporary identifier in a secondary cell from the base station. an acquisition unit that acquires a cell temporary identifier in the primary cell, wherein the using the cell temporary identifier in a secondary cell, have a, a communication unit for performing communication by the base station and the carrier aggregation, the communication unit, When the cell temporary identifier in the secondary cell is changed, the downlink and uplink communication via the secondary cell in which the cell temporary identifier is changed is stopped.

  According to the technique of an indication, the technique which can allocate C-RNTI different from a primary cell to a secondary cell is provided.

It is a figure for demonstrating the allocation method of C-RNTI in the conventional LTE. It is a figure which shows the example which bundles CC in Rel-13LTE. It is a figure which shows an example of a structure of the radio | wireless communications system which concerns on embodiment. It is a figure which shows an example of a function structure of the base station which concerns on embodiment. It is a figure which shows an example of a function structure of the user apparatus which concerns on embodiment. It is a sequence diagram which shows an example of the process sequence regarding allocation of a separate C-RNTI. It is a figure which shows an example of the setting value of Information Element. It is a figure explaining the setting value of Information Element. It is a flowchart which shows an example of the process sequence at the time of decoding DL data. It is a sequence diagram which shows an example of the process sequence (modification example) regarding allocation of individual C-RNTI. It is a sequence diagram which shows an example of a random access procedure. It is a sequence diagram which shows an example of the process sequence of a reconnection process. It is a sequence diagram which shows an example of the process sequence at the time of changing separate C-RNTI. It is a sequence diagram which shows an example of the process sequence (modification) at the time of changing separate C-RNTI. It is a sequence diagram which shows an example of the process sequence at the time of changing the existing C-RNTI. It is a figure for demonstrating C-RNTI used for CCS control.

  Embodiments of the present invention will be described below with reference to the drawings. The embodiment described below is only an example, and the embodiment to which the present invention is applied is not limited to the following embodiment. For example, although the wireless communication system according to the present embodiment assumes a system based on LTE, the present invention is not limited to LTE and can be applied to other systems. In addition, in this specification and claims, “LTE” corresponds to not only a communication method corresponding to Release 8 or 9 of 3GPP but also Release 10, 11, 12, 13, or Release 14 or later of 3GPP. It is used in a broad sense including the fifth generation communication system.

  Each cell consists of, for example, one CC or a set of downlink CC and uplink CC. In the following description, each cell may be considered synonymous with CC unless otherwise specified.

<Overview>
FIG. 3 is a diagram illustrating an example of a configuration of the wireless communication system according to the embodiment. As illustrated in FIG. 2, the radio communication system according to the present embodiment is a radio communication system including a user apparatus UE and a base station eNB, and can perform CA communication between the user apparatus UE and the base station eNB. it can.

  Further, in the example of FIG. 3, two cells (cell A and cell B) are shown, but this is also for convenience of illustration, and there may be three or more cells. Further, for example, a configuration in which an RRE connected to the base station eNB by an optical fiber or the like is provided in a place away from the base station eNB may be used.

  The base station eNB in this Embodiment allocates separately C-RNTI used for PCell communication, and C-RNTI used for SCell communication with respect to the user apparatus UE. Also, the base station eNB stores which C-RNTI is assigned to which user apparatus UE in each cell.

  This will be described more specifically with reference to FIG. In FIG. 1A, it is assumed that the cover areas of cell A and cell B overlap. When adding the cell B (SCell) to the user apparatus UE # X located in the cell A (PCell), the base station eNB sets C-RNTI # 2 as C-RNTI used for the cell B. Let it be assigned. The user apparatus UE uses C-RNTI # 1 when communicating with the base station eNB via the cell A (PCell), and C- when communicating with the base station eNB via the cell B (SCell). RNTI # 2 is used.

  Thereby, even if C-RNTI used for communication of PCell is allocated to another user apparatus in SCell, user apparatus UE can perform CA communication.

  In the present embodiment, when a plurality of SCells are added to the user apparatus UE, it is assumed that a separate C-RNTI is assigned to each added SCell. The same C-RNTI may be assigned (used) in the SCell.

  In the following description, the C-RNTI assigned to the SCell is referred to as “individual C-RNTI” for convenience. Further, in order to distinguish the C-RNTI assigned to the PCell from the individual C-RNTI, it is referred to as “existing C-RNTI” for convenience. The existing C-RNTI is synonymous with the conventional LTE C-RNTI.

  The existing C-RNTI may be referred to as “primary C-RNTI”, and the individual C-RNTI may be referred to as “secondary C-RNTI”. Further, the individual C-RNTI may be referred to as “Dedicated C-RNTI”.

<Functional configuration>
(base station)
FIG. 4 is a diagram illustrating an example of a functional configuration of the base station according to the embodiment. As illustrated in FIG. 4, the base station eNB includes a signal transmission unit 11, a signal reception unit 12, a CA control unit 13, and a C-RNTI allocation unit 14. Note that FIG. 4 shows only functional units that are particularly related to the embodiment of the present invention in the base station eNB, and has at least a function (not shown) for performing an operation based on LTE. The functional configuration shown in FIG. 4 is only an example. As long as the operation according to the present embodiment can be performed, the function classification and the name of the function unit may be anything.

  The signal transmission unit 11 includes a function of generating and wirelessly transmitting various physical layer signals from higher layer signals to be transmitted from the base station eNB. Moreover, the signal transmission part 11 transmits the existing C-RNTI or separate C-RNTI notified from the C-RNTI allocation part 14 to the user apparatus UE.

  The signal reception unit 12 includes a function of wirelessly receiving various signals from the user apparatus UE and acquiring a higher layer signal from the received physical layer signal.

  The CA control unit 13 has a function of instructing the user apparatus UE to add and delete SCell via the signal transmission unit 11 and a function of managing the configuration of the CA in the user apparatus UE.

  The C-RNTI allocation unit 14 has a function of allocating and managing an existing C-RNTI and an individual C-RNTI to each user apparatus UE. In addition, the C-RNTI allocating unit 14 notifies the signal transmitting unit 11 of the allocated existing C-RNTI or dedicated C-RNTI so that the user apparatus UE can transmit the allocated C-RNTI.

  Moreover, the C-RNTI allocation unit 14 has a function of changing an existing C-RNTI or individual C-RNTI allocated to the user apparatus UE as necessary. When changing the existing C-RNTI or the individual C-RNTI, the C-RNTI allocating unit 14 notifies the signal transmission unit 11 of the changed existing C-RNTI or individual C-RNTI.

(User device)
FIG. 5 is a diagram illustrating an example of a functional configuration of the user apparatus according to the embodiment. As illustrated in FIG. 5, the user apparatus UE includes a signal transmission unit 21, a signal reception unit 22, a CA control unit 23, a C-RNTI acquisition unit 24, and a C-RNTI setting unit 25. Note that FIG. 5 shows only functional units that are particularly related to the embodiment of the present invention in the user apparatus UE, and has at least a function (not shown) for performing an operation in conformity with LTE. The functional configuration shown in FIG. 5 is only an example. As long as the operation according to the present embodiment can be performed, the function classification and the name of the function unit may be anything.

  The signal transmission unit 21 includes a function of generating and wirelessly transmitting various physical layer signals from higher layer signals to be transmitted from the user apparatus UE. The signal receiving unit 22 includes a function of wirelessly receiving various signals from the base station eNB and acquiring a higher layer signal from the received physical layer signal. Moreover, the signal transmission part 21 and the signal reception part 22 have the function to perform CA communication, and when communicating via PCell, communicate with the base station eNB using existing C-RNTI, and SCell When performing communication via the base station, communication is performed with the base station eNB using dedicated C-RNTI. In addition, when the dedicated C-RNTI is not notified from the base station eNB, the signal transmission unit 21 and the signal reception unit 22 communicate with the base station eNB using the existing C-RNTI when communicating via the SCell. It may be.

  Further, the signal transmission unit 21 and the signal reception unit 22 activate (Activate) and deactivate (Deactivate) the SCell in response to an instruction from the CA control unit 23.

  Further, when the signal transmission unit 21 and the signal reception unit 22 are notified from the C-RNTI setting unit 25 that the individual C-RNTI is changed, the DL (Downlink) in the SCell in which the individual C-RNTI is changed, and Stops UL (Uplink) communication.

  Further, the signal transmission unit 21 and the signal reception unit 22 are notified from the CA control unit 23 that the C-RNTI acquisition unit 24 notifies that the individual C-RNTI is changed or that the SCell is deactivated. When instructed, processing for clearing various radio resources is performed. For example, the signal transmission unit 21 and the signal reception unit 22 may delete the radio resource information allocated to the deletion of data in the HARQ buffer used for communication of the secondary cell, DL communication, and / or UL communication. Good. The radio resource information may be, for example, PUCCH (Physical Uplink Control Channel resource, SRS (Sounding Reference Symbol) resource, DL scheduling information (DL Schedule Information), UL grant (UL Grant), or the like.

  In addition, the signal transmission unit 21 and the signal reception unit 22 may perform reconnection processing with the base station eNB in response to an instruction from the C-RNTI setting unit 25.

  The CA control unit 23 has a function of receiving an instruction from the base station eNB and instructing the signal transmission unit 21 and the signal reception unit 22 to perform addition and deletion of the SCell. In addition, the signal transmitting unit 21 and the signal receiving unit 22 are instructed to activate and deactivate the SCell. Further, the CA control unit 23 instructs the signal transmission unit 21 and the signal reception unit 22 to clear various radio resources when the SCell is deleted and deactivated.

  The C-RNTI acquisition unit 24 acquires the existing C-RNTI and the dedicated C-RNTI from the base station eNB, and notifies the C-RNTI setting unit 25 of the existing C-RNTI.

  The C-RNTI setting unit 25 has a function of setting an existing C-RNTI and an individual C-RNTI in each cell (PCell, SCell). Note that setting a C-RNTI in a cell means that an identifier for uniquely identifying a cell (hereinafter referred to as “cell identifier”) and a C-RNTI are stored in a memory or the like in association with each other.

  Moreover, when the C-RNTI setting unit 25 detects that the existing C-RNTI acquired from the base station eNB and the individual C-RNTI overlap (is the same), the C-RNTI setting unit 25 establishes a communication with the base station eNB. You may make it instruct | indicate to the signal transmission part 21 and the signal reception part 22 so that a reconnection process may be performed.

<Processing procedure>
Hereinafter, a processing procedure performed by the wireless communication system according to the embodiment will be described with reference to the drawings.

(Individual C-RNTI allocation)
FIG. 6 is a sequence diagram illustrating an example of a processing procedure related to allocation of individual C-RNTIs. With reference to FIG. 6, a description will be given of a processing procedure until dedicated C-RNTI is assigned simultaneously with SCell setting and communication is performed between the user apparatus UE and the base station eNB using the dedicated C-RNTI. In FIG. 6, it is assumed that the user apparatus UE communicates with the base station eNB via the PCell, and the existing C-RNTI is set in the PCell.

  In step S101, the CA control unit 13 of the base station eNB determines to add an SCell to the user apparatus UE. In addition, the C-RNTI allocation unit 14 of the base station eNB selects a C-RNTI allocated to the added SCell.

  In step S102, the signal transmission unit 11 of the base station eNB transmits an RRC Connection Reconfiguration signal to the user apparatus UE in order to cause the user apparatus UE to add an SCell. The signal includes the cell identifier of the added SCell (for example, PCI (Physical Cell Identifier), CellIndex, sCellIndex, etc.) and the individual C-RNTI.

  Here, FIG. 7 shows an example of setting values of IE (Information Element) included in the RRC Connection Reconfiguration signal. Among the setting values illustrated in FIG. 7, the setting value illustrated in the underlined portion corresponds to the individual C-RNTI. Further, FIG. 8 illustrates the setting value indicated by the underlined portion in FIG. Returning to FIG.

  In step S103, the CA control unit 23 of the user apparatus UE performs a process of adding an SCell. Further, the signal reception unit 22 and the C-RNTI acquisition unit 24 pass the individual C-RNTI acquired from the base station eNB to the C-RNTI setting unit 25. The C-RNTI setting unit 25 sets the individual C-RNTI acquired from the base station eNB to the added SCell.

  In step S104, the signal transmission unit 21 of the user apparatus UE transmits an RRC Connection Reconfiguration Complete signal to the base station eNB in order to notify the base station eNB that the addition of the SCell has been completed.

  In step S105, DL data is transmitted from the base station eNB to the user apparatus UE via the SCell.

  In step S106, the signal reception unit 22 of the user apparatus UE selects an individual C-RNTI to be used for decoding the DL data using the cell identifier of the SCell that has received the DL data, and uses the selected individual C-RNTI to perform the DL. Decrypt data. For example, the signal reception unit 22 performs DCI and transport block CRC determination using the dedicated C-RNTI, and when correctly determined, determines that the DCI and transport block are for itself.

  In step S107, UL data is transmitted from the user apparatus UE to the base station eNB via the SCell.

  In step S108, the signal receiving unit 12 of the base station eNB selects an individual C-RNTI used for decoding the UL data using the cell identifier of the SCell that has received the UL data, and uses the selected individual C-RNTI to perform the UL. Decrypt data. For example, the signal reception unit 12 performs CRC determination of the transport block using the dedicated C-RNTI, and when correctly determined, determines that the transport block is transmitted from the correct user apparatus UE.

  The processing procedure related to the allocation of the dedicated C-RNTI has been described above, but the base station eNB does not necessarily have to allocate the dedicated C-RNTI when instructing the addition of the SCell. For example, when the number of user apparatuses UE located in the base station eNB is small, it is assumed that it is appropriate to perform communication via the SCell using the existing C-RNTI as in the conventional LTE. Because.

  In this case, in the processing procedure of step S102, the base station eNB transmits an RRC Connection Reconfiguration signal that does not include the dedicated C-RNTI to the user apparatus UE, similarly to the conventional LTE.

  Moreover, in the process sequence of step S103, the C-RNTI setting unit 25 of the user apparatus UE sets the existing C-RNTI to the added SCell.

  In the processing procedure of step S106, the signal reception unit 22 of the user apparatus UE decodes DL data using the existing C-RNTI. More specifically, as illustrated in FIG. 9, the signal reception unit 12 of the user apparatus UE determines whether or not an individual C-RNTI is allocated to the SCell that has received the UL data (S151). When the dedicated C-RNTI is assigned to the SCell, the DL data is tried to be decoded using the dedicated C-RNTI (S152). On the other hand, when the individual C-RNTI is not assigned to the SCell, the DL data is tried to be decoded using the existing C-RNTI (C-RNTI assigned to the PCell) (S153).

  The allocation of the individual C-RNTI described above may be limited to a case where a predetermined number of CCs are set in the user apparatus UE. In addition, a predetermined number of CCs are activated (activated) in the user apparatus UE, or UL timing is taken for the UL (a TA (Time Alignment) timer of a TAG (Timing Advance Group) to which the cell belongs). It may be limited to the case) The predetermined number may be 5CC. This is because the C-RNTI collision does not become a problem if it is up to 5 CC as in the conventional CA.

(Assignment of individual C-RNTI (variation))
FIG. 10 is a sequence diagram illustrating an example of a processing procedure (variation example) related to allocation of individual C-RNTIs. In the allocation (variation example) of dedicated C-RNTI, the base station eNB notifies the user apparatus UE of a plurality of C-RNTIs including the existing C-RNTI and the dedicated C-RNTI in advance, and adds SCel. Which C-RNTI is assigned to the SCell.

  In step S201, the C-RNTI allocation unit 14 of the base station eNB selects a plurality of C-RNTIs to be allocated to the user apparatus UE. The C-RNTI allocation unit 14 may select an existing C-RNTI and one individual C-RNTI, or assume that CA communication using a plurality of SCells is performed, and the existing C-RNTI and A plurality of individual C-RNTIs may be selected.

  In step S202, the signal transmission unit 11 of the base station eNB selects the existing C-RNTI selected in step S201, one or more individual C-RNTIs, and an identifier for uniquely identifying the one or more individual C-RNTIs (for convenience). , Referred to as “individual C-RNTI identifier”) is transmitted in the C-RNTI notification signal to the user apparatus UE. Note that the C-RNTI notification signal may be, for example, a RACH response (Random Access Response). In the case of RACH Response, the existing C-RNTI may be transmitted to the user apparatus UE as a Temporary C-RNTI in conventional LTE.

  In addition, the signal transmission unit 11 of the base station eNB transmits the existing C-RNTI to the user apparatus UE in the random access procedure performed before the processing procedure of step S202, and the processing procedure of step S202. The C-RNTI notification signal transmitted in (1) may include one or more individual C-RNTIs and individual C-RNTI identifiers. In this case, the C-RNTI notification signal may be a signal transmitted by a physical layer (for example, PDCCH, EPDCCH, PDSCH, etc.). The C-RNTI notification signal may be a MAC CE (Control Element) in a MAC (Media Access Control) layer.

  In step S203, the signal reception unit 22 and the C-RNTI acquisition unit 24 of the user apparatus UE set the C-RNTI and the individual C-RNTI and the individual C-RNTI identifier among the plurality of C-RNTIs acquired from the base station eNB. Pass to part 25. The C-RNTI setting unit 25 stores one or more individual C-RNTI and an identifier for uniquely identifying the individual C-RNTI in the memory.

  In step S204, the CA control unit 13 of the base station eNB determines to add an SCell to the user apparatus UE. In addition, the C-RNTI allocating unit 14 selects one individual C-RNTI to be allocated to the added SCell from one or more individual C-RNTIs transmitted to the user apparatus UE in the processing procedure of Step S202.

  In step S205, the signal transmission unit 11 of the base station eNB transmits an RRC Connection Reconfiguration signal to the user apparatus UE in order to cause the user apparatus UE to add an SCell. The signal includes a cell identifier of the added SCell (for example, PCI, CellIndex, sCellIndex, etc.) and an individual C-RNTI identifier corresponding to the individual C-RNTI selected in the processing procedure of step S204. Yes.

  In step S206, the CA control unit 23 of the user apparatus UE performs a process of adding an SCell. In addition, the C-RNTI setting unit 25 reads the individual C-RNTI corresponding to the individual C-RNTI identifier received in the processing procedure of step S205 from the memory, and sets it to the added SCell.

  In step S207, the signal transmission unit 21 of the user apparatus UE transmits an RRC Connection Reconfiguration Complete signal to the base station eNB in order to notify the base station eNB that the addition of the SCell has been completed.

  According to the processing procedure (variation example) related to the allocation of the individual C-RNTI described above, when adding the SCell, instead of notifying the user apparatus UE of the individual C-RNTI itself, only the individual C-RNTI identifier is used. Since it only needs to be notified, it is possible to reduce the signal amount of the signal transmitted from the base station eNB to the user apparatus UE when adding the SCell.

(Random access processing)
FIG. 11 is a sequence diagram illustrating an example of a random access procedure. A processing procedure in the case where a contention based random access procedure is performed will be described with reference to FIG.

  In the contention-based random access procedure in the conventional LTE, it is specified that the user apparatus UE includes the C-RNTI in Msg3 (Message3) and transmits it to the base station eNB. Therefore, in the present embodiment, the user apparatus UE may include the individual C-RNTI in Msg3 and notify the base station eNB.

  In step S301, the signal transmission unit 21 of the user apparatus UE transmits Random Access Preamble to the base station eNB.

  In step S302, the signal transmission unit 11 of the base station eNB transmits a Random Access Response.

  In step S303, the C-RNTI setting unit 25 of the user apparatus UE selects a C-RNTI to be transmitted to the base station eNB using Msg3. For example, the C-RNTI setting unit 25 may select an existing C-RNTI set in the PCell, or may select an individual C-RNTI. When selecting an individual C-RNTI, the C-RNTI setting unit 25 may select an individual C-RNTI set in the SCell having the smallest cell identifier, or the SCell having the largest cell identifier. Alternatively, the individual C-RNTI set in the above may be selected.

  In addition, when CA communication is performed, it is assumed that signals transmitted and received between the base station eNB and the user apparatus UE in a series of random access procedures are transmitted and received across the PCell and one or more SCells. The For example, it is assumed that Random Access Preamble is transmitted / received via PCell, and signals after Random Access Response are transmitted / received via SCell.

  In this case, the C-RNTI setting unit 25 may select a C-RNTI set in a cell (any one of the PCell and one or more SCells) that has received the Random Access Response. In addition, the C-RNTI setting unit 25 is set to a cell that transmits Msg3 (a cell that is any one of PCell and one or more SCells, and is previously defined to transmit Msg3). A C-RNTI may be selected. In addition, the C-RNTI setting unit 25 may select a C-RNTI set in a cell (any one of the PCell and one or more SCells) that has transmitted the Random Access Preamble. In addition, the base station eNB instructs the user apparatus UE in advance which cell (PCell and one of the one or more SCells) should include the C-RNTI in the Msg3, and the C-RNTI setting unit 25 may select the C-RNTI of the indicated cell.

  In step S304, the signal transmission unit 21 of the user apparatus UE includes the C-RNTI selected in step S303 in Msg3 and transmits it to the base station eNB.

  In step S305, the signal reception unit 12 of the base station eNB uniquely identifies the user apparatus UE that has transmitted the Random Access Preamble in step S301 using the C-RNTI included in Msg3. In addition, the base station eNB has grasped | ascertained all which C-RNTI was allocated to which user apparatus UE. Therefore, the base station eNB can uniquely identify the user apparatus UE from the C-RNTI included in Msg3.

(Reconnection process)
FIG. 12 is a sequence diagram illustrating an example of a processing procedure of reconnection processing. A processing procedure when the reconnection process is performed will be described with reference to FIG.

  In the conventional LTE, it is specified that the user apparatus UE includes C-RNTI in the RRC Connection Re-establishment Request transmitted in the reconnection process. Therefore, in the present embodiment, the user apparatus UE may include the dedicated C-RNTI in the RRC signal and notify the base station eNB.

  In step S401, the user apparatus UE determines to perform a reconnection process.

  The processing procedure from step S402 to step S404 is the same as the processing procedure from step S301 to step S303 in FIG.

  In step S405, the signal transmission unit 21 of the user apparatus UE includes the C-RNTI selected in step S303 in the RRC Connection Re-establishment Request and transmits it to the base station eNB.

  In step S406, the signal reception unit 12 of the base station eNB uniquely identifies the user apparatus UE that has transmitted the Random Access Preamble in step S402 using the C-RNTI included in the RRC Connection Re-establishment Request. Note that the signal reception unit 12 of the base station eNB uniquely identifies the user apparatus UE using the C-RNTI included in the RRC signal, the cell identifier (PCI) and the shortMAC-I included in the RRC signal. You may do it.

(Individual C-RNTI change processing)
In conventional LTE, when changing C-RNTI (existing C-RNTI) allocated to the user apparatus UE, the base station eNB causes the user apparatus UE to execute random access processing again using Intra-cell HO. C-RNTI was changed. On the other hand, when changing the individual C-RNTI in the present embodiment, it is not necessary to change the existing C-RNTI, so that the individual C-RNTI can be changed without performing the Intra-cell HO processing procedure. Is desirable.

  However, when changing the dedicated C-RNTI, a mismatch between the dedicated C-RNTI occurs between the base station eNB and the user apparatus UE until the change of the dedicated C-RNTI is completed on the user apparatus UE side. Therefore, there is a possibility that normal communication cannot be performed. Therefore, in the present embodiment, communication performed in the SCell is temporarily stopped until the change of the individual C-RNTI is completed.

  FIG. 13 is a sequence diagram illustrating an example of a processing procedure when changing the individual C-RNTI. The process procedure at the time of changing the separate C-RNTI allocated to the user apparatus UE is demonstrated using FIG.

  In step S501, the C-RNTI allocation unit 14 of the base station eNB sends an individual C-RNTI change instruction signal to the user apparatus UE via the signal transmission unit 11 in order to change the individual C-RNTI allocated to the user apparatus UE. Send to. The individual C-RNTI change instruction signal may include, for example, an individual C-RNTI before the change and an individual C-RNTI after the change. Further, the individual C-RNTI change instruction signal may include an individual C-RNTI identifier corresponding to the individual C-RNTI before the change and the individual C-RNTI after the change. Further, the individual C-RNTI change instruction signal includes the cell identifier (for example, PCI, CellIndex, sCellIndex, etc.) of the cell in which the individual C-RNTI before the change is set, and the individual C-RNTI after the change. You may do it.

  The dedicated C-RNTI change instruction signal may be an RRC Connection Reconfiguration signal, another RRC signal, or a MAC CE used in the MAC layer.

  In step S502, the signal transmission unit 21 and the signal reception unit 22 of the user apparatus UE stop the DL and UL communication in the SCell in which the individual C-RNTI is changed. Further, the C-RNTI acquisition unit 24 of the user apparatus UE notifies the changed individual C-RNTI to the C-RNTI setting unit 25, and the C-RNTI setting unit 25 changes the changed individual C-RNTI. Set to SCell corresponding to previous individual C-RNTI.

  In addition, the signal transmission unit 21 and the signal reception unit 22 of the user apparatus UE autonomously deactivate the SCell corresponding to the changed individual C-RNTI according to an instruction from the CA control unit 23, thereby performing DL and UL. The communication may be stopped.

  Further, the signal transmission unit 21 and the signal reception unit 22 of the user apparatus UE suppress UL communication in the SCell by regarding that the TA timer of the TAG to which the SCell corresponding to the changed individual C-RNTI belongs has expired. You may make it do. Further, the signal transmission unit 21 and the signal reception unit 22 delete (flush) the data in the HARQ buffer in the SCell by regarding that the TA timer has expired, and perform DL scheduling information (DL Schedule Information), UL grant ( (UL Grant) may be cleared.

  Further, the signal transmission unit 21 and the signal reception unit 22 of the user apparatus UE may not consider various radio resource information in the SCell corresponding to the changed individual C-RNTI as valid (valid). . In addition, the signal transmission unit 21 and the signal reception unit 22 of the user apparatus UE may autonomously release various radio resources by deleting the various radio resource information. The various radio resource information may be, for example, information on PUCCH resources, information on SRS resources, DL scheduling information, UL grant, and the like.

  In step S503, the signal transmission unit 21 and the signal reception unit 22 of the user apparatus UE notify the base station eNB that the change of the dedicated C-RNTI is completed and the DL and UL communication can be started (restarted). In order to do so, an individual C-RNTI change completion notification signal is transmitted to the base station eNB. The individual C-RNTI change completion notification signal may be, for example, an RRC Connection Reconfiguration Complete signal. In addition, the signal transmission unit 21 and the signal reception unit 22 of the user apparatus UE start (restart) DL and UL communication with the base station eNB after transmitting the individual C-RNTI change completion notification signal.

(Individual C-RNTI change processing (modified example))
FIG. 14 is a sequence diagram illustrating an example of a processing procedure (modification) when changing the individual C-RNTI. The process procedure (modification) at the time of changing the separate C-RNTI allocated to the user apparatus UE will be described using FIG.

  In step S601, the CA control unit 13 of the base station eNB transmits an RRC Connection Reconfiguration signal to the user apparatus UE via the signal transmission unit 11 in order to delete the SCell for changing the dedicated C-RNTI.

  In step S602, the CA control unit 23 of the user apparatus UE deletes the SCell instructed in step S601, and transmits an RRC Connection Reconfiguration Complete signal to the user apparatus UE via the signal transmission unit 21.

  Subsequently, the base station eNB and the user apparatus UE perform a process of adding an SCell again using the processing procedure of steps S101 to S104 in FIG. Note that, in the processing procedure of step S102, the signal transmission unit 11 of the base station eNB notifies the user apparatus UE of the changed individual C-RNTI.

  In addition, deletion and addition of SCell may be performed within the same RRC procedure and the same RRC signal. That is, the RRC signals used in the processing procedures of Step S601 and Step S102 may be the same RRC signal, and the RRC signals used in the processing procedures of Step S602 and Step S104 may be the same RRC signal. .

(Existing C-RNTI change process)
As described above, in the conventional LTE, when changing the existing C-RNTI, the base station eNB changes the existing C-RNTI by causing the user apparatus UE to execute the random access process again using Intra-cell HO. .

  In this case, depending on the mounting of the base station eNB, it is assumed that the changed existing C-RNTI overlaps with the individual C-RNTI. On the other hand, the user apparatus UE can consider the case where the duplication of the existing C-RNTI and the individual C-RNTI is allowed or not allowed.

  Hereinafter, when the duplication between the existing C-RNTI and the individual C-RNTI is not allowed, the processing procedure performed by the user apparatus UE, and when the duplication between the existing C-RNTI and the individual C-RNTI is allowed, the user apparatus UE Will be described.

  FIG. 15 is a sequence diagram illustrating an example of a processing procedure when changing an existing C-RNTI.

  First, a processing procedure performed by the user apparatus UE when the overlap between the existing C-RNTI and the individual C-RNTI is not allowed will be described.

  In step S702, the signal transmission unit 11 of the base station eNB transmits the RRC Connection Reconfiguration signal including the Mobility Control Information to the user apparatus UE, thereby causing the user apparatus UE to execute Intra-cell HO. Subsequently, the intra-cell HO processing procedure is performed between the user apparatus UE and the base station eNB, and the changed existing C-RNTI is notified to the user apparatus UE.

  In step S703, the C-RNTI setting unit 25 of the user apparatus UE detects that the existing C-RNTI and the individual C-RNTI overlap. The signal transmission unit 21 and the signal reception unit 22 cause the base station eNB to allocate another existing C-RNTI by performing a reconnection procedure with the base station eNB.

  Next, a processing procedure performed by the user apparatus UE when overlapping between the existing C-RNTI and the individual C-RNTI is allowed will be described.

  First, the processing procedure of step S702 described above is performed. Subsequently, in step S704, the C-RNTI setting unit 25 of the user apparatus UE detects that the existing C-RNTI and the individual C-RNTI overlap. Subsequently, the C-RNTI setting unit 25 may discard the individual C-RNTI (delete it from the memory), or may not store the individual C-RNTI (delete it from the memory) and hold it as it is. May be.

(Processing procedure in CCS control)
In LTE Rel-10, CCS (Cross Carrier Scheduling) control is introduced. In CCS control, scheduling information related to the SCell can be included in the PDCCH transmitted via the PCell.

  FIG. 16 is a diagram for explaining C-RNTI used for CCS control. In FIG. 16, it is assumed that cell A is a PCell (that is, a cell to which scheduling information is transmitted) and cell B is an SCell.

  The signal transmission unit 21 and the signal reception unit 22 of the user apparatus UE transmit the PDCCH (S801), the PDSCH (S802) transmitted from the base station eNB via the cell A, and the PUSCH transmitted to the base station eNB via the cell A. When performing the processing for (S803), the existing C-RNTI is used.

  In addition, the signal transmission unit 21 and the signal reception unit 22 of the user apparatus UE include the PDSCH (S803) transmitted from the base station eNB via the cell B and the PUSCH (S805) transmitted to the base station eNB via the cell B. When performing the processing for, the individual C-RNTI is used.

  Moreover, the information transmitted by PUCCH format 3 (S806) is multiplied by a scramble sequence determined based on C-RNTI or the like in order to randomize interference between user apparatuses UE. Therefore, the signal transmission unit 21 of the user apparatus UE may use an existing C-RNTI (C-RNTI set in the PCell) as the C-RNTI used when determining the scramble sequence. Moreover, the signal transmission part 21 of the user apparatus UE has the most CC index among UCI (Uplink Control Information) of each CC (each cell) transmitted by PUCCH as C-RNTI used when determining a scramble sequence. The C-RNTI of a small CC (cell) may be used, or the C-RNTI of a CC (cell) having the largest CC index may be used. Further, the signal transmission unit 21 of the user apparatus UE may use the individual C-RNTI having the smallest number among the individual C-RNTIs, or the individual C-RNTI having the largest number among the individual C-RNTIs. RNTI may be used. In addition, as long as C-RNTI used when determining a scramble sequence is C-RNTI predetermined between the base station eNB and the user apparatus UE, which C-RNTI may be used. .

<Summary>
As described above, according to the embodiment, in a radio communication system supporting carrier aggregation, a user apparatus that communicates with a base station, from the base station, a cell temporary identifier in a primary cell, a cell temporary identifier in a secondary cell, And a communication unit that performs communication by carrier aggregation with the base station using a cell temporary identifier in the primary cell and a cell temporary identifier in the secondary cell. . By this user apparatus UE, the technique which can allocate C-RNTI different from a primary cell to a secondary cell is provided.

  Further, the communication unit performs a random access procedure with the base station via a primary cell or a secondary cell, and sends a message 3 including a cell temporary identifier in the primary cell or a cell temporary identifier in the secondary cell to the base You may make it transmit to a station. Thereby, the user apparatus UE can use the dedicated C-RNTI in the random access procedure. Also, the base station eNB can uniquely identify the user apparatus UE using the dedicated C-RNTI in the random access procedure.

  The communication unit is prescribed in advance to transmit a random access preamble via a primary cell, or to receive a random access response signal from a primary cell, or to transmit a message 3 via a primary cell. If the base station specifies that the message 3 includes a temporary cell identifier in the primary cell, the message 3 including the temporary cell identifier in the primary cell is transmitted to the base station. When the preamble is transmitted through the secondary cell, when the random access response signal is received from the secondary cell, or when it is preliminarily specified that the message 3 is transmitted through the secondary cell, or the message 3 includes the secondary SE In the case where the inclusion of cells temporary identifier is specified from the base station, the message 3 including the cell temporary identifier in the secondary cell may be transmitted to the base station. Thereby, in a series of random access procedures, even if a signal transmitted and received between the base station eNB and the user apparatus UE is transmitted and received across the PCell and one or more SCells, the user apparatus UE is appropriately It is possible to notify the base station eNB of a C-RNTI.

  In addition, when the cell temporary identifier in the secondary cell is changed, the communication unit may stop downlink and uplink communication via the secondary cell in which the cell temporary identifier is changed. Thereby, until the change of the dedicated C-RNTI is completed on the user apparatus UE side, a communication abnormality that may occur due to a mismatch of the dedicated C-RNTI between the base station eNB and the user apparatus UE Can be prevented in advance. Moreover, unlike the conventional LTE, the base station eNB and the user apparatus UE can change the individual C-RNTI without performing the Intra-cell HO processing procedure. Also, this can prevent the throughput from being lowered when the individual C-RNTI is changed.

  The communication unit may deactivate downlink and uplink communication by deactivating a secondary cell whose cell temporary identifier has been changed. Thereby, user apparatus UE can divert the processing procedure used by the conventional LTE, when stopping communication at the time of change of individual C-RNTI.

  Further, the communication unit deletes data in the HARQ buffer in the secondary cell whose cell temporary identifier has been changed, and deletes radio resource information allocated to at least one of downlink and uplink communications. Also good. Thereby, when the individual C-RNTI is changed, the user apparatus UE is affected by unnecessary radio resource information or the like (for example, malfunction that may occur due to the presence of unnecessary radio resource information in the memory). Can be eliminated.

  Further, the communication unit is a case where the cell temporary identifier in the primary cell is changed, and the changed cell temporary identifier in the primary cell is the same as the cell temporary identifier in the secondary cell, A reconnection process may be performed with the base station. Thereby, when the duplication of the existing C-RNTI and the dedicated C-RNTI is not allowed in the user apparatus UE, it is possible to cause the base station eNB to allocate a new existing C-RNTI.

  In addition, when the cell temporary identifier in the secondary cell is not acquired in the acquisition unit, the communication unit communicates with the base station using the cell temporary identifier in the primary cell instead of the cell temporary identifier in the secondary cell. You may do it. Thereby, the base station eNB can control whether to allocate the individual C-RNTI to the user apparatus UE according to the number of user apparatuses UE located in the base station eNB, for example. Can be assigned C-RNTI. In addition, when performing CA communication, the user apparatus UE does not always need to use the existing C-RNTI and the individual C-RNTI separately, thereby reducing the processing load during CA communication.

In addition, as described above, according to the embodiment, a radio communication system that supports carrier aggregation and includes a base station and a user apparatus, wherein the base station includes a cell temporary identifier in a primary cell and a cell temporary in a secondary cell. A transmission unit that transmits an identifier to a user apparatus, and the user apparatus acquires, from the base station, a cell temporary identifier in the primary cell and a cell temporary identifier in the secondary cell;
A wireless communication system is provided that includes a communication unit that performs communication by carrier aggregation with the base station using the temporary cell identifier in the primary cell and the temporary cell identifier in the secondary cell. This wireless communication system provides a technology that can assign a C-RNTI different from that of the primary cell to the secondary cell.

  In addition, as described above, according to the embodiment, there is provided a communication method performed by a radio communication system that supports carrier aggregation and includes a base station and a user apparatus, wherein the base station includes a cell temporary identifier in a primary cell, a secondary cell Transmitting a cell temporary identifier in a cell to a user apparatus, the user apparatus obtaining a cell temporary identifier in the primary cell and a cell temporary identifier in the secondary cell from the base station, and the user There is provided a communication method including a step of performing communication with the base station by carrier aggregation using a cell temporary identifier in the primary cell and a cell temporary identifier in the secondary cell. By this communication method, a technique capable of assigning a C-RNTI different from that of the primary cell to the secondary cell is provided.

<Supplement of embodiment>
Each signal may be a message. For example, the C-RNTI notification signal may be a C-RNTI notification message. The individual C-RNTI change instruction signal may be an individual C-RNTI change instruction message. The individual C-RNTI change completion notification signal may be an individual C-RNTI change completion notification message.

  As described above, the configuration of each device (user device UE / base station eNB) described in the embodiment of the present invention is realized by executing the program by the CPU (processor) in the device including the CPU and the memory. It may be a configuration, may be a configuration realized by hardware such as a hardware circuit provided with processing logic described in the present embodiment, or may be a mixture of programs and hardware Good.

  Although the embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various variations, modifications, alternatives, substitutions, and the like. I will. Although specific numerical examples have been described in order to facilitate understanding of the invention, these numerical values are merely examples and any appropriate values may be used unless otherwise specified. The classification of items in the above description is not essential to the present invention, and the items described in two or more items may be used in combination as necessary, or the items described in one item may be used in different items. It may be applied to the matters described in (if not inconsistent). The boundaries between functional units or processing units in the functional block diagram do not necessarily correspond to physical component boundaries. The operations of a plurality of functional units may be physically performed by one component, or the operations of one functional unit may be physically performed by a plurality of components. The order of the sequences and flowcharts described in the embodiments may be changed as long as there is no contradiction. For convenience of processing description, the user apparatus UE and the base station eNB have been described using functional block diagrams. However, such an apparatus may be realized by hardware, software, or a combination thereof. The software operated by the processor of the user apparatus UE according to the embodiment of the present invention and the software operated by the processor of the base station eNB according to the embodiment of the present invention are random access memory (RAM), flash memory, and read-only, respectively. The data may be stored in a memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or any other suitable storage medium.

  The present invention is not limited to the above embodiments, and various modifications, modifications, alternatives, substitutions, and the like are included in the present invention without departing from the spirit of the present invention.

  In the embodiment, the existing C-RNTI is an example of a cell temporary identifier in the primary cell. The dedicated C-RNTI is an example of a temporary cell identifier in the secondary cell. The C-RNTI acquisition unit 24 is an example of an acquisition unit. The signal transmission unit 21, the signal reception unit 22, the CA control unit 23, and the C-RNTI setting unit 25 are examples of a communication unit. The signal transmission unit 11 is an example of a transmission unit.

eNB base station UE user apparatus 11 signal transmission unit 12 signal reception unit 13 CA control unit 14 C-RNTI allocation unit 21 signal transmission unit 22 signal reception unit 23 CA control unit 24 C-RNTI acquisition unit 25 C-RNTI setting unit

Claims (9)

In a wireless communication system supporting carrier aggregation, a user apparatus that communicates with a base station,
From the base station, an acquisition unit for acquiring a cell temporary identifier in a primary cell and a cell temporary identifier in a secondary cell;
Using the cell temporary identifier in the primary cell and the cell temporary identifier in the secondary cell, a communication unit that performs communication by means of carrier aggregation with the base station,
I have a,
The said communication part is a user apparatus which stops the communication of the downlink and uplink via the secondary cell from which the cell temporary identifier is changed, when the cell temporary identifier in the said secondary cell is changed .   The communication unit performs a random access procedure with the base station via a primary cell or a secondary cell, and sends a message 3 including a cell temporary identifier in the primary cell or a cell temporary identifier in the secondary cell to the base station. The user apparatus according to claim 1, which transmits the user apparatus. When the communication unit transmits a random access preamble via a primary cell, receives a random access response signal from the primary cell, or transmits a message 3 via the primary cell. Or when the base station specifies that the message 3 includes a cell temporary identifier in the primary cell, the message 3 including the cell temporary identifier in the primary cell is transmitted to the base station,
When the random access preamble is transmitted via the secondary cell, when the random access response signal is received from the secondary cell, or when it is specified in advance that the message 3 is transmitted via the secondary cell, or the message 3 The user apparatus of Claim 2 which transmits the message 3 containing the cell temporary identifier in the said secondary cell to the said base station, when including the cell temporary identifier in the said secondary cell is designated from the said base station. The user apparatus according to claim 1 , wherein the communication unit stops downlink and uplink communication by deactivating a secondary cell whose cell temporary identifier has been changed. The communication unit deletes the data in the HARQ buffers in the secondary cell cells temporary identifiers have been modified to delete the radio resource information allocated to at least one of downlink communication and uplink claim 1 or 5. The user device according to 4 . The communication unit is configured when the cell temporary identifier in the primary cell is changed, and the changed cell temporary identifier in the primary cell is the same as the cell temporary identifier in the secondary cell. The user apparatus as described in any one of Claims 1 thru | or 5 which performs a reconnection process between the stations. When the cell temporary identifier in the secondary cell in the acquisition unit is not acquired, the communication unit performs communication by the base station and carrier aggregation with cells temporary identifier in the primary cell, any one of claims 1 to 6 A user device according to item. A wireless communication system that supports carrier aggregation and has a base station and user equipment,
The base station
A transmitter that transmits a temporary cell identifier in the primary cell and a temporary cell identifier in the secondary cell to the user equipment;
Have
The user equipment is
From the base station, an acquisition unit that acquires a cell temporary identifier in the primary cell and a cell temporary identifier in the secondary cell;
Using the cell temporary identifier in the primary cell and the cell temporary identifier in the secondary cell, a communication unit that performs communication by means of carrier aggregation with the base station,
I have a,
The said communication part is a radio | wireless communications system which stops the communication of the downlink and uplink via the secondary cell from which the cell temporary identifier is changed, when the cell temporary identifier in the said secondary cell is changed . A communication method that supports carrier aggregation and is performed by a wireless communication system having a base station and a user device,
The base station transmitting a cell temporary identifier in a primary cell and a cell temporary identifier in a secondary cell to a user equipment;
The user equipment obtaining from the base station a cell temporary identifier in the primary cell and a cell temporary identifier in the secondary cell;
The user equipment performs communication by means of carrier aggregation with the base station using a cell temporary identifier in the primary cell and a cell temporary identifier in the secondary cell;
I have a,
The step of performing the communication includes a step of stopping downlink and uplink communication via the secondary cell in which the cell temporary identifier is changed when the cell temporary identifier in the secondary cell is changed .

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