JP2018056856A - User device, base station and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique which can reduce the data amount of radio signals transmitted between a user device and a base station.SOLUTION: In a mobile communication system including the base station and the user device, the user device which communicates with the base station includes: PDCP layer processing means having storage means to receive and store by a plurality of acknowledgement signals transmitted to the base station; and RLC layer processing means which transmits to the PDCP layer processing means a signal transmission permission signal, which indicates that the transmission of an uplink signal is possible. The PDCP layer processing means, when receiving the signal transmission permission signal, transmits to the RLC layer processing means a plurality of acknowledgement signals, including a last received acknowledgement signal, among the plurality of acknowledgement signals stored in the storage means.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a user apparatus, a base station, and a communication method.

  In the conventional TCP (Transmission Control Protocol) operation, when the server receives an acknowledgment (TCP ACK packet) from the client, the TCP packets up to the sequence number indicated in the acknowledgment number (Acknowledgement Number) included in the acknowledgment are Operates as if all were received.

  Basically, the server sends an acknowledgment to the client every time it receives a TCP packet from the client. Here, a technique for reducing the number of confirmation responses transmitted from the server to the client is known (see, for example, Patent Document 1).

  According to Patent Literature 1, when transmitting a plurality of confirmation responses to the client, the server discards the old confirmation response and transmits only the new confirmation response to the client.

US Patent Application Publication No. US6338131B1

  A mobile communication system that supports LTE (Long Term Evolution) relays various data transmitted and received between a user apparatus and a server using wireless communication. On the other hand, since the radio capacity that can be used in the mobile communication system is limited, it is important to reduce the amount of data transmitted and received using radio signals as much as possible.

  Here, for example, it is conceivable to reduce the amount of data relayed using a radio signal by applying the technique described in Patent Document 1 to a mobile communication system. However, the technique described in Patent Document 1 is intended for TCP communication in a general server and client, and is not assumed to be applied to a mobile communication system that supports LTE.

  The disclosed technique has been made in view of the above, and an object of the present invention is to provide a technique capable of reducing the data amount of a radio signal transmitted between a user apparatus and a base station.

  A user apparatus of the disclosed technique is a user apparatus that communicates with the base station in a mobile communication system having a base station and a user apparatus, and receives and stores a plurality of acknowledgment signals transmitted to the base station in the previous period. PDCP layer processing means having storage means for transmitting and RLC layer processing means for transmitting a signal transmission permission signal indicating that transmission of an uplink signal is possible to the PDCP layer processing means, and the PDCP layer processing When the means receives the signal transmission permission signal, the means transmits, to the RLC layer processing means, a plurality of confirmation response signals including the last received confirmation response signal among the plurality of confirmation response signals stored in the storage means. To do.

  According to the disclosed technique, a technique capable of reducing the data amount of a radio signal transmitted between a user apparatus and a base station is provided.

It is a figure which shows the structural example of the mobile communication system which concerns on embodiment. It is a figure which shows an example of the TCP process which the user apparatus which concerns on embodiment performs. It is a flowchart which shows an example of the TCP process which the user apparatus which concerns on embodiment performs. It is a sequence diagram which shows an example of the process sequence which the mobile communication system which concerns on embodiment performs. It is a figure which shows the modification of the TCP process which the user apparatus which concerns on embodiment performs. It is a flowchart which shows the modification of the TCP process which the user apparatus which concerns on embodiment performs. 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 figure which shows an example of the hardware constitutions of the base station and user apparatus which concern on embodiment.

  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, the mobile communication system according to the present embodiment assumes a system based on LTE, but the present invention is not limited to LTE and can be applied to other systems. In this specification and claims, “LTE” corresponds to not only a communication method corresponding to 3GPP release 8 or 9, but also 3GPP release 10, 11, 12, 13, or 14 or later. It is used in a broad sense including 5th generation (5G) communication systems.

  In the following description, the processing procedure will be described by taking the case of using TCP as an example. The present embodiment can be applied to other protocols as long as the protocol is used for session management.

<System configuration>
FIG. 1 is a diagram illustrating a configuration example of a mobile communication system according to an embodiment. As shown in FIG. 1, the mobile communication system in the embodiment includes a user apparatus UE and a base station 10. Although one user apparatus UE is illustrated in FIG. 1, for convenience of illustration, a plurality of user apparatuses UE may be included.

  The user apparatus UE has a function of communicating with the base station 10 and the like through radio. The user apparatus UE is, for example, a mobile phone, a smartphone, a tablet, a mobile router, a wearable terminal, an MTC (Machine Type Communication) terminal, or the like. The user apparatus UE may be any user apparatus as long as the apparatus has a communication function. The user apparatus UE is configured by hardware resources such as a CPU such as a processor, a memory apparatus such as a ROM, a RAM, or a flash memory, an antenna for communicating with the base station 10, and an RF (Radio Frequency) apparatus. Each function and process of the user apparatus UE may be realized by a processor processing or executing data or a program stored in the memory device. However, the user apparatus UE is not limited to the hardware configuration described above, and may have any other appropriate hardware configuration.

  The base station 10 performs communication between the user apparatus UE and the core network. The base station 10 is a hardware resource such as a CPU such as a processor, a memory device such as a ROM, a RAM, or a flash memory, an antenna for communicating with the user apparatus UE, a communication interface apparatus for communicating with an adjacent base station, etc. Consists of. Each function and process of the base station 10 may be realized by a processor processing or executing data or a program stored in a memory device. However, the base station 10 is not limited to the hardware configuration described above, and may have any other appropriate hardware configuration.

<Processing procedure>
Hereinafter, the processing procedure performed by the mobile communication system according to the present embodiment will be described with reference to the drawings. In the following description, the processing procedure will be described by taking the case of using TCP as an example, but the present invention is not limited to this.

(About processing procedures in each layer)
FIG. 2 is a diagram illustrating an example of a TCP process performed by the user apparatus according to the embodiment. As shown in FIG. 2, the user apparatus UE includes a MAC layer that performs MAC (Media Access Control) processing, an RLC layer that performs RLC (Radio Link Control) processing, and a PDCP layer that performs PDCP (Packet Data Convergence Protocol) processing. And a TCP layer that performs TCP processing. In FIG. 2, the user apparatus UE establishes a TCP connection with a server (not shown) existing on a predetermined PDN (Packet Data Network) connected to the mobile communication system according to the embodiment. It is assumed that communication is performed with the server using TCP.

  First, the TCP layer passes a TCP ACK packet (hereinafter referred to as “ACK packet”) to be transmitted to the server to the PDCP layer. Subsequently, the PDPP layer temporarily holds the ACK packet passed from the TCP layer in a buffer until an instruction from the RLC layer is received.

  Here, the MAC layer requests the base station 10 to allocate radio resources (UL (Uplink) grant) in the uplink signal in order to transmit uplink data. When the UL grant is received from the base station 10, the MAC layer transmits a transmission opportunity notification to the RLC layer in order to notify the RLC layer that the uplink signal resource has been allocated. The transmission opportunity notification transmitted from the MAC layer to the RLC layer is, for example, Notification of a transmission opportunity.

  Similarly, the RLC layer transmits a transmission opportunity notification to the PDCP layer in order to notify the PDCP layer that an uplink signal resource has been allocated. The transmission opportunity notification transmitted from the RLC layer to the PDCP layer is, for example, Notification of a transmission opportunity.

  When receiving the transmission opportunity notification from the RLC layer, the PDCP layer stores an ACK packet in a PDCP PDU (Protocol Data Unit) and transmits the packet to the RLC layer. Here, when a plurality of ACK packets exist in the buffer, the PDCP layer stores only the ACK packet received last from the TCP layer in the PDCP PDU and transmits it to the RLC layer.

  Subsequently, the RLC layer generates an RLC PDU from the PDCP PDU including the ACK packet and transmits the RLC PDU to the MAC layer. The MAC layer transmits the RLC PDU to the base station 10 using the radio resource indicated by the UL grant.

  A specific example will be described with reference to FIG. First, it is assumed that five ACK packets (P1 to P5) from the TCP layer are passed from the TCP layer to the PDCP layer. In this state, it is assumed that a transmission opportunity notification is transmitted from the MAC layer to the RLC layer (S1), and further a transmission opportunity notification is transmitted from the RLC layer to the MAC layer (S2).

  In this case, the PDCP layer that has received the transmission opportunity notification stores only the last received ACK packet (that is, the P5 ACK packet) among the five ACK packets in the PDCP PDU and transmits it to the RLC layer (S3). . Also, the RLC layer generates an RLC PDU from the PDCP PDU including the ACK packet and transmits it to the MAC layer (S4).

  Here, the acknowledgment number is included in the ACK packet. As specified in the TCP specifications, the acknowledgment number is obtained by adding 1 to the sequence number of a series of TCP packets that the user apparatus UE has received from the server without loss. Is a number. Accordingly, the acknowledgment number included in the P5 ACK packet is equal to or larger than at least the acknowledgment numbers included in the four ACK packets P1 to P4.

  That is, if the server can receive the P5 ACK packet, the server can recognize that the TCP packet up to the acknowledgment number included in the ACK packet has arrived. That is, the server does not need to receive ACK packets P1 to P4. Therefore, when receiving the transmission opportunity notification, the PDCP layer passes only the ACK packet received last from the TCP layer to the RLC layer. Thereby, it becomes possible to reduce the data amount of the radio signal transmitted between the user apparatus UE and the base station 10.

  Further, when the PDCP layer receives a SACK (Selective ACK) packet from the TCP layer, the PDCP layer handles the SACK packet in the same manner as the ACK packet. In other words, when receiving the transmission opportunity notification, the PDCP layer passes only the ACK packet or SACK packet received last from the TCP layer to the RLC layer.

  For example, in FIG. 2, assuming that P1 to P4 are ACK packets and P5 is a SACK packet, the PDCP layer transmits the SACK packet of P5 to the RLC layer in step S3. For example, assuming that P1 is a SACK packet and P2 to P5 are ACK packets in FIG. 2, the PDCP layer transmits the P5 ACK packet to the RLC layer in step S3.

  As defined in the TCP specification, SACK includes the sequence number of a TCP packet that has already been received, in addition to the above-described acknowledgment number. By using SACK, the user apparatus UE can notify the server of the sequence numbers of TCP packets that have already been received among the TCP packets having sequence numbers after the acknowledgment number.

(About processing procedure in PDCP layer)
FIG. 3 is a flowchart illustrating an example of a TCP process performed by the user apparatus according to the embodiment. The process procedure performed in the PDCP layer of the user apparatus UE will be specifically described with reference to FIG. In FIG. 3, the processing procedure from step S10 to step S14 is repeated every time the PDCP layer receives an ACK (SACK) packet.

  In step S10, the PDCP layer receives an ACK (SACK) packet from the TCP layer.

  In step S11, the PDCP layer stores the ACK (SACK) packet received from the TCP layer in a buffer. Note that the PDCP layer can identify the order in which the ACK (SACK) packets are received from the TCP layer. For example, the PDCP layer may add information indicating the reception order to the ACK (SACK) packet and store the information in a buffer, or hold information that records a time stamp or the like when the ACK (SACK) packet is received. May be.

  In step S12, when the PDCP layer receives a transmission opportunity notification from the RLC layer, the PDCP layer proceeds to the processing procedure of step S13. If a transmission opportunity notification has not been received, the process proceeds to step S10.

  In step S13, the PDCP layer transmits a PDCP PDU including an ACK (SACK) packet received last among the ACK (SACK) packets accumulated in the buffer to the RLC layer. When information indicating the reception order is added to the ACK (SACK) packet in step S11, the PDCP layer transmits a PDCP PDU including the ACK (SACK) packet from which the information is deleted to the RLC layer. Note that the PDCP PDU transmitted to the RLC layer in step S13 may include data to be transmitted to the base station 10 (for example, uplink user data) in addition to the ACK (SACK) packet.

  In step S13, the PDCP layer may transmit a PDCP PDU including an ACK (SACK) packet having the largest acknowledgment number among the ACK (SACK) packets accumulated in the buffer to the RLC layer. Although the PDCP layer needs to read the acknowledgment number in each ACK (SACK) packet stored in the buffer, the order of the ACK (SACK) packet transmitted from the TCP layer to the PDCP layer should be changed. Even in such a case, it becomes possible to reliably transmit the ACK (SACK) packet having the largest acknowledgment number to the base station 10.

  In step S14, the PDCP layer discards (deletes) all ACK (SACK) packets stored in the buffer. Thereafter, the process proceeds to step S10.

(About processing sequence)
The user apparatus UE according to the embodiment does not necessarily perform the TCP process (that is, the TCP process illustrated in FIGS. 2 and 3) in the present embodiment, but may perform the process based on an instruction from the base station 10. Good. Further, the TCP processing in the present embodiment may be performed in a predetermined unit.

  FIG. 4 is a sequence diagram illustrating an example of a processing procedure performed by the mobile communication system according to the embodiment.

  In step S101, the user apparatus UE may transmit a capability notification signal to the base station 10. The capability notification signal includes information (hereinafter referred to as “capability information”) indicating that the user apparatus UE itself has processing capability to perform TCP processing in the present embodiment. The capability notification signal may be, for example, an RRC signal (for example, UE Capability Information), a MAC signal, or a physical layer signal.

  Note that the capability information may include a specific number of radio bearers (DRB (Data Radio Bearer) number) or / and logical channel numbers that can simultaneously perform the TCP processing in the present embodiment. Further, the capability information may include the number of TCP sessions that can simultaneously perform the TCP processing in the present embodiment. In addition, a specific UE category may be determined in advance between the base station 10 and the user apparatus UE, and the specific UE category may be stored in the capability information. In this case, the base station 10 grasps the processing capability (the number of radio bearers, the number of logical channels, or the number of TCP sessions) of the user apparatus UE itself based on the specific UE category.

  In addition, when the user apparatus UE, the base station 10, and the core network support Control plane CIoT EPS optimization specified in Release 13 of LTE, the user apparatus UE is about a radio bearer (SRB (Signaling Radio Bearer)). Also, the TCP processing in the present embodiment may be operated. In this case, even if the capability information includes the specific number of radio bearers (the number of DRBs and / or the number of SRBs) or / and the number of logical channels that can simultaneously perform the TCP processing in the present embodiment. Good. Control plane CIoT EPS optimization is a technology that allows user data to be transmitted / received between the user apparatus UE and the base station 10 without establishing a DRB by allowing user data to be transmitted / received via the SRB. is there.

  In step S102, the base station 10 transmits an activation instruction signal to the user apparatus UE in order to instruct the user apparatus UE to operate the TCP processing in the present embodiment. Here, when transmitting a starting instruction | indication signal from the base station 10 to the user apparatus UE, several forms are considered as follows.

[Mode 1: User equipment UE unit]
The base station 10 may instruct the user apparatus UE to operate the TCP processing in the present embodiment. Note that instructing for each user apparatus UE means instructing a predetermined user apparatus UE to operate the TCP processing in the present embodiment on all radio bearers (DRB and / or SRB). . In this case, the activation instruction signal may be an RRC Connection Reconfiguration signal or a predetermined MAC CE (Control Element). Further, the Radio Resource Config Dedicated IE (Information Element) included in the RRC signal may include an IE indicating whether or not the TCP processing in the present embodiment should be operated. Note that the base station 10 transmits the activation instruction signal when the user apparatus UE receives a notification that the user apparatus UE has the processing capability to perform the TCP processing in the present embodiment in the processing procedure of step S101. Also good.

  In step S103, the user apparatus UE that has received the activation instruction signal according to mode 1 causes the TCP process in the present embodiment to operate in the TCP process of the PDCP layer in all radio bearers (DRB and / or SRB). To.

[Mode 2: Radio bearer unit]
The base station 10 may instruct the user apparatus UE of one or a plurality of radio bearers that operate the TCP processing in the present embodiment. In this case, the activation instruction signal may be an RRC Connection Reconfiguration signal. Further, in the RadioResourceConfigDedicated IE included in the RRC signal, the PDCP-Config specified for each DRB may include an IE indicating whether or not the TCP processing in the present embodiment should be operated, or the SRB. An IE indicating whether or not the TCP processing in the present embodiment should be operated may be included every time. Further, an ID (for example, SRB Identity, DRB Identity) that uniquely identifies a radio bearer that operates the TCP processing in the present embodiment, or an LCID (Logical Channel ID) that uniquely identifies a logical channel is assigned to the MAC CE. It may be included. In addition, the base station 10 operates the TCP processing in the present embodiment within the range of the processing capability (the number of radio bearers or the number of logical channels) notified from the user apparatus UE in the processing procedure of Step S101. You may make it instruct | indicate a radio bearer.

  In step S103, the user apparatus UE that has received the activation instruction signal according to mode 2 is configured to operate the TCP process according to the present embodiment in the TCP process of the PDCP layer in the designated radio bearer (SRB, DRB). To do.

[Mode 3: TCP session unit]
The base station 10 may instruct the user apparatus UE of one or a plurality of TCP sessions for operating the TCP processing in the present embodiment. In this case, the activation instruction signal may include an identifier (hereinafter referred to as “TCP session ID”) that uniquely identifies each of one or more TCP sessions. Further, the activation instruction signal may be an RRC Connection Reconfiguration signal or a MAC CE. The TCP session ID may include, for example, a TCP packet source IP address and TCP port, and a TCP packet source IP address and TCP port. Further, the base station 10 may acquire the TCP session ID from an MME (Mobility Management Entity).

  The base station 10 instructs one or a plurality of TCP sessions for operating the TCP processing in the present embodiment within the range of the processing capability (the number of TCP sessions) notified from the user apparatus UE in the processing procedure of step S101. You may make it do.

  In step S103, the user apparatus UE that has received the activation instruction signal according to mode 3 causes the TCP processing according to the present embodiment to operate when performing TCP communication related to the TCP session specified in the PDCP layer. .

<Processing procedure (modification)>
In the processing procedure described above, when a plurality of ACK (SACK) packets exist in the buffer, the PDCP layer stores only the ACK (SACK) packet received last from the TCP layer in the PDCP PDU and transmits it to the RLC layer. I did it. However, there is a possibility that the ACK (SACK) packet is lost before reaching the server, for example, when the transmission path between the core network and the server is unstable. A server that could not receive an ACK (SACK) packet will perform retransmission of downlink user data and the like, causing not only a delay of downlink user data but also a waste of radio resources. May cause. Therefore, in the present modification, when there are a plurality of ACK (SACK) packets in the buffer, the PDCP layer transmits a plurality of ACK (SACK) packets including the ACK (SACK) packet last received from the TCP layer to the PDCP PDU. Store and send to RLC layer.

  Hereinafter, a processing procedure (modification) performed by the mobile communication system according to the present embodiment will be described. Further, the processing procedure described so far is referred to as a basic example in order to distinguish it from the present modification. Regarding the system configuration and processing procedure described in the basic example, points that are not particularly mentioned in the following description also apply to this modification.

(About processing procedures in each layer)
Since the processing procedure performed by the TCP layer and the RLC layer is the same as that of the basic example, the description thereof is omitted. When receiving the transmission opportunity notification from the RLC layer, the PDCP layer stores an ACK packet in a PDCP PDU (Protocol Data Unit) and transmits the packet to the RLC layer. Here, when there are a plurality of ACK (SACK) packets in the buffer, the PDCP layer stores a plurality of ACK packets including the ACK (SACK) packet received last from the TCP layer in the PDCP PDU and transmits them to the RLC layer. To do.

  A specific example will be described with reference to FIG. Steps S5 and S6 in FIG. 5 are the same as steps S1 and S2 in FIG. The PDCP layer that has received the transmission opportunity notification includes a plurality of ACK (SACK) packets including the last received ACK (SACK) packet (that is, P5 ACK (SACK) packet) among the five ACK (SACK) packets. The data is stored in the PDCP PDU and transmitted to the RLC layer (S7). The RLC layer generates an RLC PDU from the PDCP PDU including the plurality of ACK packets and transmits it to the MAC layer (S8).

(About processing procedure in PDCP layer)
The process procedure (modification) performed in the PDCP layer of the user apparatus UE will be specifically described with reference to FIG. In FIG. 6, the processing procedure from step S20 to step S24 is repeated every time the PDCP layer receives an ACK (SACK) packet. The processing procedures of Step S20, Step S21, Step S22, and Step S24 are the same as Step S10, Step S11, Step S12, and Step S14 of FIG.

  In step S23, the PDCP layer stores, in the PDCP PDU, a plurality of ACK (SACK) packets including the last received ACK (SACK) packet among the ACK (SACK) packets accumulated in the buffer and transmits them to the RLC layer. To do. The PDCP layer has a plurality of ACK packets (for example, P5 and P4 ACK (SACK) in the reverse order received from the TCP layer (in the example of FIG. 5, the order of P5, P4, P3, P2, and P1). ) Packets) may be stored in PDCP PDUs and transmitted to the RLC layer. Further, the present invention is not limited to this, and an arbitrary plurality of ACK (SACK) packets among the ACK (SACK) packets accumulated in the buffer may be stored in the PDCP PDU and transmitted to the RLC layer.

  In step S23, the PDCP layer stores, in the PDCP PDU, a plurality of ACK (SACK) packets including an ACK (SACK) packet having the largest acknowledgment number among ACK (SACK) packets accumulated in the buffer. You may make it transmit to a RLC layer. Also, the PDCP layer may store a plurality of ACK (SACK) packets in the PDCP PDU in the descending order of the acknowledgment number among the ACK (SACK) packets accumulated in the buffer and transmit them to the RLC layer.

(Supplementary information)
In this modification, the number of ACK (SACK) packets (number of ACK (SACK) packets to be transmitted) stored in the PDCP PDU by the PDCP layer may be determined in advance according to standard specifications or the like. May be instructed by In the latter case, the base station 10 may instruct the user apparatus UE by including the number of ACK (SACK) packets to be stored in the PDCP PDU in the activation instruction in the processing procedure of step S102 of FIG. Then, the user apparatus UE may be instructed using broadcast information (broadcast information) or RRC signaling. If the number of ACK (SACK) packets to be stored in the PDCP PDU is 1, the user apparatus UE performs the operation described in the basic example.

  Moreover, in this modification, the user apparatus UE may operate as follows. First, the PDCP layer of the user apparatus UE indicates “number of ACK (SACK) packets to be stored in PDCP PDU” (or “number of ACK (SACK) packets to be stored in PDCP PDU”) instructed from the base station 10. Is notified to the MAC layer as “data available for transmission” indicating the data size that is the basis of the BSR. Subsequently, the MAC layer notifies the base station 10 of a BSR (Buffer Status Report) having a buffer size capable of storing the ACK (SACK) packets of the notified “number of ACK (SACK) packets to be stored in PDCP PDU”. To do. When there is uplink user data to be transmitted to the base station 10, the MAC layer notifies the base station 10 of a BSR having a buffer size capable of storing the user data and an ACK (SACK) packet. Also good. Subsequently, the base station 10 allocates UL radio resources corresponding to the notified BSR, and transmits a UL grant indicating the allocated radio resources to the user apparatus UE. When receiving the UL grant, the MAC layer of the user apparatus UE notifies the RLC layer of a transmission opportunity notification (S5 in FIG. 5). Subsequently, the RLC layer notifies the PDCP layer of a transmission opportunity notification (S6 in FIG. 5). Subsequently, the PDCP layer stores a plurality of ACK (SACK) packets including the last received ACK (SACK) packet in the PDCP PDU and transmits them to the RLC layer (S7 in FIG. 5).

  The processing procedure (modified example) has been described above. Depending on the processing procedure (modified example), even if a part of a plurality of ACK (SACK) packets transmitted from the user apparatus UE is lost, the remaining ACK (SACK) packets reach the server. become. Accordingly, it is possible to suppress the possibility of transmission delay of downlink user data, and it is possible to suppress the possibility that radio resources are consumed wastefully.

<Supplementary notes on the processing procedure for basic examples and modifications>
If the MAC layer notifies the base station 10 of a buffer size BSR that can store all the TCP ACKs accumulated in the PDCP layer buffer, only one or a plurality of TCP ACKs are received in the basic example and the modified example. Since it is transmitted to the base station 10, there is a possibility that uplink radio resources allocated by the UL grant are wasted. In order to prevent the occurrence of such a problem, “data available for transmission” indicating the data size that is the basis of the BSR notified from the PDCP layer to the MAC layer is one of the following: May be defined as
The data size corresponding to one TCP ACK is at least “data available for transmission”.
The data size corresponding to a predetermined number of TCP ACKs is at least “data available for transmission”. Note that the predetermined number may be determined in advance according to standard specifications, or may be set in advance from the base station 10 to the user apparatus UE using broadcast information (broadcast information) or RRC signaling.
The data size corresponding to a predetermined number of TCP ACKs out of the total number of TCP ACKs stored in the PDCP layer buffer is at least “data available for transmission”. Note that the predetermined ratio may be determined in advance by standard specifications, or may be set in advance from the base station 10 to the user apparatus UE using broadcast information (broadcast information) or RRC signaling. For example, when the predetermined ratio is 1/2 and 10 TCP ACKs are accumulated in the PDCP layer buffer, the PDCP layer transmits at least a data size corresponding to 5 TCP ACKs. Notify the MAC layer as “data available for transmission”. Thereafter, the PDCP layer discards a TCP ACK (a TCP ACK having an old timing accumulated in a buffer of the PDCP layer or a TCP ACK having an old TCP ACK number) that has not been transmitted to the base station 10.

<Functional configuration>
Next, an example of functional configurations of the user apparatus UE and the base station 10 that perform the processing procedure described above will be described. Note that the user apparatus UE and the base station 10 may be able to execute both the basic example and the modified example, or may be able to execute only one of them.

(base station)
FIG. 5 is a diagram illustrating an example of a functional configuration of the base station according to the embodiment. As illustrated in FIG. 5, the base station 10 includes a signal transmission unit 11, a signal reception unit 12, a capability storage unit 13, and an instruction unit 14. FIG. 5 shows only functional units particularly related to the embodiment of the present invention in the base station 10, 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 executed, the function classification and the name of the function unit may be anything.

  The signal transmission unit 11 includes a function of generating various types of physical layer signals from a higher layer signal to be transmitted from the base station 10 and wirelessly transmitting the signals.

  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. In addition, the signal reception unit 12 receives capability information from the user apparatus UE and stores the capability information in the capability storage unit 13.

  The capability storage unit 13 stores the capability information received by the signal receiving unit 12 in a memory for each user apparatus UE.

  The instruction unit 14 instructs the user apparatus UE to operate the TCP process in the present embodiment. The instruction unit 14 instructs the user apparatus UE to operate the TCP processing in the present embodiment within the range of the processing capacity of the user apparatus UE based on the capability information stored in the capability storage unit 13. You may make it do. In addition, the instruction unit 14 may instruct the user apparatus UE to operate the TCP processing in the present embodiment in units of user apparatuses UE, in units of radio bearers, or in units of TCP sessions.

  In addition, the instruction unit 14 instructs the user apparatus UE the number of confirmation response signals to be transmitted from the user apparatus UE.

(User device)
FIG. 6 is a diagram illustrating an example of a functional configuration of the user apparatus according to the embodiment. As shown in FIG. 6, the user apparatus UE includes a signal transmission unit 21, a signal reception unit 22, a capability notification unit 23, a MAC processing unit 24, an RLC processing unit 25, a PDCP processing unit 26, and session management. And a protocol processing unit 27. Note that FIG. 6 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 based on LTE. The functional configuration shown in FIG. 6 is only an example. As long as the operation according to the present embodiment can be executed, 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 10 and acquiring a higher layer signal from the received physical layer signal.

  The capability notification unit 23 indicates that it has the capability to transmit the last received acknowledgment (or the plurality of acknowledgments including the last received acknowledgment) among the plurality of acknowledgments stored in the buffer. Information is notified to the base station 10.

  The MAC processing unit 24 performs various processes related to the MAC layer. When receiving an UL grant from the base station 10, a transmission opportunity notification is transmitted to the RLC processing unit 25 in order to notify the RLC processing unit 25 that an uplink signal can be transmitted.

  The RLC processing unit 25 transmits / receives RLC PDUs to / from the base station 10 and performs various processes related to the RLC layer. In addition, when a transmission opportunity notification is received from the MAC processing unit 24, a transmission opportunity notification is transmitted to the PDCP processing unit 26 in order to notify the PDCP processing unit 26 that an uplink signal can be transmitted.

  The PDCP processing unit 26 has a buffer implemented using a memory. In addition, the PDCP processing unit 26 stores the confirmation response (ACK packet or SACK packet) received from the session management protocol processing unit 27 in a buffer. In addition, when the PDCP processing unit 26 operates according to the basic example, when the transmission opportunity notification is notified from the RLC processing unit 25, the PDCP processing unit 26 includes the last received confirmation response among the confirmation responses stored in the buffer. The PDU is transmitted to the RLC processing unit 25. In addition, when the PDCP processing unit 26 operates according to the modification, when the transmission opportunity notification is notified from the RLC processing unit 25, the PDCP processing unit 26 includes a plurality of confirmation responses that are received last among the confirmation responses stored in the buffer. The PDCP PDU including the confirmation response is transmitted to the RLC processing unit 25.

  In addition, when the PDCP processing unit 26 operates according to the basic example and the modification example, when the transmission opportunity notification is notified from the RLC processing unit 25, among the confirmation responses stored in the buffer, “at least received last” A PDCP PDU including one or more confirmation responses including an acknowledgment may be transmitted to the RLC processing unit 25. In addition, when the transmission opportunity notification is notified from the RLC processing unit 25, the PDCP processing unit 26 selects one or more (or a plurality) of confirmation responses stored in the buffer in the order opposite to the order of reception. A PDCP PDU including an “acknowledgment response” may be transmitted to the RLC processing unit 25.

  Further, when the PDCP processing unit 26 operates according to the basic example, the PDCP PDU including the confirmation response having the largest confirmation response number among the confirmation responses stored in the buffer may be transmitted to the RLC processing unit 25. Good. Further, when the PDCP processing unit 26 operates according to the modified example, when the transmission opportunity notification is notified from the RLC processing unit 25, among the confirmation responses stored in the buffer, the “confirmation response with the largest confirmation response number” A PDCP PDU including a plurality of confirmation responses including “” may be transmitted to the RLC processing unit 25.

  Further, when the PDCP processing unit 26 operates according to the basic example and the modification example, when the transmission opportunity notification is notified from the RLC processing unit 25, among the confirmation responses stored in the buffer, “at least the confirmation response number is A PDCP PDU including one or more confirmation responses including the largest confirmation response may be transmitted to the RLC processing unit 25. In addition, when the transmission opportunity notification is notified from the RLC processing unit 25, the PDCP processing unit 26 selects “one or more (or a plurality) of confirmation responses in the order of larger confirmation response numbers from among the confirmation responses stored in the buffer. A PDCP PDU including "may be transmitted to the RLC processing unit 25.

  Further, the PDCP processing unit 26 may switch whether or not to perform the processing based on an instruction from the base station 10, for example. Further, for example, based on an instruction from the base station 10, the PDCP processing unit 26 may switch whether or not to perform the processing in units of radio bearers (DRB) or TCP sessions. The PDCP processing unit 26 may include the number of confirmation responses instructed from the base station 10 in the PDCP PDU.

  Further, the PDCP processing unit 26 determines, as data that can be transmitted, a predetermined size out of a data size corresponding to a predetermined number (one or a plurality) of confirmation response signals or a total number of confirmation response signals stored in the storage unit. The MAC layer may be notified of the data size corresponding to the ratio number of acknowledgment signals.

  The session management protocol processing unit 27 performs, for example, various processes in TCP packet transmission / reception (session management and the like) and various processes in IP packet transmission / reception.

<Hardware configuration>
The block diagrams (FIGS. 7 and 8) used in the description of the above embodiment show functional unit blocks. 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 base station 10 and the user apparatus UE according to an embodiment of the present invention may function as a computer that performs processing of the communication method of the present invention. FIG. 9 is a diagram illustrating an example of a hardware configuration of the base station and the user apparatus according to the embodiment. The base station 10 and the user apparatus UE described above 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 base station 10 and the user apparatus UE 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 base station 10 and the user apparatus UE 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, communication by the communication apparatus 1004, and memory 1002. This is realized by controlling reading and / or writing of data in 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, the signal transmission unit 11 of the base station 10, the signal reception unit 12, the capability storage unit 13, the instruction unit 14, the signal transmission unit 21 of the user apparatus UE, the signal reception unit 22, and the capability notification unit 23 The MAC processing unit 24, the RLC processing unit 25, the PDCP processing unit 26, and the session management protocol processing unit 27 may be realized by the processor 1001.

  In addition, the processor 1001 reads a program (program code), software module, or 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, the signal transmission unit 11 of the base station 10, the signal reception unit 12, the capability storage unit 13, the instruction unit 14, the signal transmission unit 21 of the user apparatus UE, the signal reception unit 22, and the capability notification unit 23 The MAC processing unit 24, the RLC processing unit 25, the PDCP processing unit 26, and the session management protocol processing unit 27 may be realized by a control program stored in the memory 1002 and operating on the processor 1001. The functional block may be similarly realized. 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 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, the signal transmission unit 11 and the signal reception unit 12 of the base station 10 and the signal transmission unit 21 and the signal reception unit 22 of the user apparatus UE 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 base station 10 and the user apparatus UE 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.

<Summary>
As described above, according to the present embodiment, in a mobile communication system having a base station and a user apparatus, a user apparatus that communicates with the base station, and a plurality of confirmations transmitted to the previous base station PDCP layer processing means having storage means for receiving and storing a response signal; and RLC layer processing means for transmitting a signal transmission permission signal indicating that transmission of an uplink signal is possible to the PDCP layer processing means, And the PDCP layer processing means, when receiving the signal transmission permission signal, out of a plurality of confirmation response signals stored in the storage means, a plurality of confirmation response signals including the last received confirmation response signal A user equipment for transmitting to the RLC layer processing means is provided. The user apparatus UE provides a technique capable of reducing the data amount of a radio signal transmitted between the user apparatus and the base station.

  The PDCP layer processing means discards the plurality of confirmation response signals stored in the storage means after transmitting a plurality of confirmation response signals including the last received confirmation response signal to the RLC layer processing means. You may make it do. With this configuration, it is possible to prevent unnecessary confirmation response signals from being stored in the memory of the user apparatus UE, and it is possible to efficiently use memory resources.

  Further, the previous PDCP layer processing means, when instructed by the base station, out of a plurality of confirmation response signals stored in the storage means, a plurality of confirmation response signals including the last received confirmation response signal You may make it perform the process transmitted to a RLC layer process means. With this configuration, the user apparatus UE can operate the TCP process according to the present embodiment in accordance with an instruction from the base station 10.

  In addition, the previous PDCP layer processing means includes a lastly received confirmation response signal among a plurality of confirmation response signals stored in the storage means for a radio bearer or communication session instructed from the base station. You may make it perform the process which transmits a several confirmation response signal to the said RLC layer process means. With this configuration, the user apparatus UE can operate the TCP processing in the present embodiment in units of radio bearers or communication sessions. Also, with this configuration, it is possible to operate the TCP processing in the present embodiment while considering the balance between the processing capability of the user apparatus UE itself and the amount of radio signal data to be reduced.

  Further, the PDCP layer processing means performs a process of transmitting the number of confirmation response signals indicated by the base station to the RLC layer processing means as a plurality of confirmation response signals including the last received acknowledgment signal. It may be. With this configuration, the base station 10 can arbitrarily instruct the number of confirmation response signals to be transmitted to the user apparatus UE.

  In addition, the PDCP layer processing unit may transmit, as data that can be transmitted, a data size corresponding to a predetermined number of acknowledgment signals, or the number of predetermined ratios among the total number of acknowledgment signals stored in the storage unit. The data size corresponding to the confirmation response signal may be notified to the MAC layer. With this configuration, it is possible to suppress the possibility that uplink radio resources are wasted.

  Further, the previous PDCP layer processing means performs a process of transmitting a plurality of confirmation response signals including the last received confirmation response signal to the RLC layer processing means among the plurality of confirmation response signals stored in the storage means. You may make it have a notification means to notify the said base station of the capability information which shows a processing capability. With this configuration, the user apparatus UE can instruct the base station 10 to specify the number of radio bearers or the number of communication sessions for operating the TCP processing in the present embodiment within a range not exceeding its own processing capability. become.

  Further, according to the present embodiment, in a mobile communication system having a base station and a user apparatus, the base station communicates with the user apparatus, and a plurality of confirmation response signals are transmitted in the PDCP layer of the user apparatus. Receiving means for receiving capability information indicating processing capability for performing processing for transmitting a plurality of acknowledgment signals including the last received acknowledgment signal to the RLC layer; and a PDCP layer of the previous user apparatus based on the previous capability information And an instruction means for instructing the user equipment to perform a process of transmitting a plurality of acknowledgment signals including the last received acknowledgment signal among the plurality of acknowledgment signals to the RLC layer. A station is provided. The base station 10 provides a technique capable of reducing the data amount of a radio signal transmitted between the user apparatus and the base station.

  Further, according to the present embodiment, in a mobile communication system having a base station and a user apparatus, a communication method performed by the user apparatus communicating with the base station, wherein a plurality of confirmation responses are transmitted to the base station in the previous period. Receiving a signal and storing it in the storage means of the PDCP layer; transmitting a signal transmission permission signal indicating that transmission of an uplink signal is possible from the RLC layer to the PDCP layer; A step of transmitting a plurality of acknowledgment signals including an acknowledgment signal received last among a plurality of acknowledgment signals stored in the storage means to the RLC layer when a signal transmission permission signal is received; A communication method is provided. This communication method provides a technique capable of reducing the data amount of a radio signal transmitted between the user apparatus and the base station.

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

<Supplement of embodiment>
As described above, the present embodiment can be applied to other protocols as long as the protocol is used for session management. For example, the present invention can also be applied when communication using QUIC (Quick UDP Internet Connection) is performed between the user apparatus UE and the server instead of TCP. In this case, for example, the session management protocol processing unit 27 performs session management using QUIC. In addition, the PDCP processing unit 26 stores the QUIIC confirmation response in the buffer, and when the transmission opportunity notification is notified from the RLC processing unit 25, the last of the QUIC confirmation responses accumulated in the buffer. The PDCP PDU including the received QUIIC confirmation response is transmitted to the RLC processing unit 25.

  The configuration of each device (user device UE / base station 10) described in the present embodiment is a configuration realized by executing a program by a CPU (processor) in the device including a CPU and a memory. Alternatively, a configuration realized by hardware such as a hardware circuit including processing logic described in this embodiment may be used, or a program and hardware may be mixed.

  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. 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 description of the processing, the user apparatus UE and the base station 10 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 10 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.

  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 / embodiment described in this specification is directed to the user apparatus UE using Long Term Evolution (LTE), LTE-A (LTE-Advanced), SUPER 3G, I broadcast information (broadcast information), or RRC signaling. You may make it do. MT-Advanced, 4G, 5G, FRA (Future Radio Access), 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), Bluetooth (registered trademark), other appropriate systems using systems, and / or next-generation systems extended based on these systems Also good.

  As long as there is no contradiction, the order of the processing procedures, sequences, flowcharts, and the like of each aspect / embodiment 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 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.

  Each aspect / embodiment described in this specification may be used independently, may be used in combination, or may be switched according to execution.

  The user equipment UE 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, It may also be referred to as a wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other appropriate terminology.

  Base station 10 may also be referred to by those skilled in the art as NB (NodeB), eNB (enhanced NodeB), base station, or some other suitable terminology.

  As used herein, the terms “determining” and “determining” may encompass a wide variety of actions. “Judgment” and “determination” are, for example, judgment, calculation, calculation, processing, derivation, investigating, looking up (eg, table , Searching in a database or another data structure), considering ascertaining as “determining”, “deciding”, and the like. 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”.

  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.”

  As long as the terms “including”, “including”, and variations thereof are used herein or in the claims, these terms are similar to the term “comprising”. 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.

  Throughout this disclosure, if articles are added by translation, for example, a, an, and the in English, these articles must be clearly indicated otherwise in context, Including multiple things.

  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.

  In the embodiment, the PDCP processing unit 26 is an example of a PRCP layer processing unit. The RLC processing unit 25 is an example of an RLC layer processing unit. The buffer is an example of a storage unit. The transmission opportunity notification is an example of a signal transmission permission signal. The capability notification unit 23 is an example of a notification unit. The signal receiving unit 12 is an example of a receiving unit. The instruction unit 14 is an example of an instruction unit.

UE user apparatus 10 base station 11 signal transmission unit 12 signal reception unit 13 capability storage unit 14 instruction unit 21 signal transmission unit 22 signal reception unit 23 capability notification unit 24 MAC processing unit 25 RLC processing unit 26 PDCP processing unit 27 session management protocol processing Unit 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device

Claims (9)

In a mobile communication system having a base station and a user device, the user device communicates with the base station,
PDCP layer processing means having storage means for receiving and storing a plurality of acknowledgment signals transmitted to the base station in the previous period;
RLC layer processing means for transmitting a signal transmission permission signal indicating that transmission of an uplink signal is possible to the PDCP layer processing means;
Have
When the PDCP layer processing means receives the signal transmission permission signal, among the plurality of confirmation response signals stored in the storage means, the PDCP layer processing means outputs a plurality of confirmation response signals including the last received confirmation response signal to the RLC layer. User device that transmits to the processing means.   The PDCP layer processing means discards the plurality of confirmation response signals stored in the storage means after transmitting a plurality of confirmation response signals including the last received confirmation response signal to the RLC layer processing means, The user device according to claim 1.   The previous PDCP layer processing means, when instructed by the base station, out of the plurality of confirmation response signals stored in the storage means, includes a plurality of confirmation response signals including the last received confirmation response signal in the RLC layer. The user device according to claim 1, wherein the user device performs processing to be transmitted to the processing means.   The previous period PDCP layer processing means includes a plurality of confirmation response signals received last among a plurality of confirmation response signals stored in the storage means for a radio bearer or communication session instructed from the base station. The user apparatus according to claim 3, wherein processing for transmitting an acknowledgment signal to the RLC layer processing unit is performed.   The PDCP layer processing means performs processing for transmitting the number of confirmation response signals indicated by the base station to the RLC layer processing means as a plurality of confirmation response signals including the last received acknowledgment signal. The user apparatus as described in any one of 1-4.   The PDCP layer processing means transmits, as transmittable data, a data size corresponding to a predetermined number of confirmation response signals, or a confirmation ratio of a predetermined ratio out of the total number of confirmation response signals stored in the storage means. The user apparatus as described in any one of Claims 1 thru | or 5 which notifies the data size corresponding to a signal to a MAC layer.   Processing capacity for performing processing in which the previous PDCP layer processing means transmits a plurality of confirmation response signals including the last received confirmation response signal to the RLC layer processing means among the plurality of confirmation response signals stored in the storage means The user apparatus according to claim 1, further comprising a notification unit configured to notify the base station of capability information indicating In a mobile communication system having a base station and a user device, a base station that communicates with the user device,
In the PDCP layer of the user apparatus, receiving means for receiving capability information indicating processing capability of performing processing for transmitting a plurality of acknowledgment signals including the last received acknowledgment signal among the plurality of acknowledgment signals to the RLC layer When,
Based on the previous period capability information, the PDCP layer of the previous period user apparatus performs a process of transmitting, to the RLC layer, a plurality of acknowledgment signals including the last received acknowledgment signal among the plurality of acknowledgment signals. An instruction means for instructing the user device;
Base station with In a mobile communication system having a base station and a user device, a communication method performed by a user device communicating with the base station,
Receiving a plurality of acknowledgment signals transmitted to the previous base station and storing them in a storage means of the PDCP layer;
Transmitting a signal transmission permission signal indicating that transmission of an uplink signal is possible from the RLC layer to the PDCP layer;
When the previous PDCP layer receives the signal transmission permission signal, it transmits to the RLC layer a plurality of acknowledgment signals including the last received acknowledgment signal among the plurality of acknowledgment signals stored in the storage means. Steps,
A communication method comprising:

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