KR20190016875A - Method and apparatus for enhancing reliability of data transmission in wireless communication system - Google Patents

Abstract

The present disclosure relates to a method and apparatus for enhancing reliability of data transmission in a wireless communication system. According to an embodiment of the present invention, a method of a terminal for performing a packet data convergence protocol (PDCP) duplication in a wireless communication system comprises the steps of: receiving from a base station a PDCP duplication activation indication information for at least one of a first type data radio bearer (DRB) or a second type DRB; performing PDCP duplication for a new uplink data packet when PDCP replication for the second type DRB is activated; and transmitting a data packet mapped to each DRB through one or more of the at least one of the first type DRB or the second type DRB.

Description

TECHNICAL FIELD The present invention relates to a method and apparatus for enhancing data transmission reliability in a wireless communication system,

This disclosure relates to wireless communication systems, and more particularly, to methods and apparatus for improving the reliability of data transmission.

The International Telecommunication Union (ITU) has been developing IMT (International Mobile Telecommunication) frameworks and standards, and is currently under discussion for 5G (5G) communication through a program called "IMT for 2020 and beyond" .

In order to meet the requirements of "IMT for 2020 and beyond ", the 3rd Generation Partnership Project (3GPP) NR (New Radio) system, considering various scenarios, service requirements and potential system compatibility, It is being discussed in support of diverse numerology of resource unit standards. In addition, it is discussed that the NR system supports data transmission requiring high reliability such as URL Reliability Low Latency Communication (URLLC). Packet Data Convergence Protocol (PDCP) duplication can be applied as an example for enhancing the reliability of data transmission. However, a method for applying PDCP replication to data to be newly transmitted by a terminal has not yet been specifically defined.

SUMMARY OF THE INVENTION It is a technical object of the present disclosure to provide a method and apparatus for improving the reliability of data transmission in a wireless communication system.

It is a further technical object of the present invention to provide a method and apparatus for supporting PDCP replication of a data packet newly transmitted by a UE.

The technical objects to be achieved by the present disclosure are not limited to the above-mentioned technical subjects, and other technical subjects which are not mentioned are to be clearly understood from the following description to those skilled in the art It will be possible.

A method for performing a Packet Data Convergence Protocol (PDCP) replication in a wireless communication system according to an aspect of the present disclosure includes performing PDCP replication for one or more of at least one first type DRB (Data Radio Bearer) Receiving activation indication information from a base station; Performing PDCP replication for a new uplink data packet when PDCP replication for the second type DRB is activated; And transmitting a data packet mapped to each DRB through one or more of the one or more first type DRBs or the second type DRBs.

The features briefly summarized above for this disclosure are only exemplary aspects of the detailed description of the disclosure which follow, and are not intended to limit the scope of the disclosure.

According to the present disclosure, a method and apparatus for improving the reliability of data transmission in a wireless communication system can be provided.

According to the present disclosure, a method and apparatus for supporting PDCP replication of a data packet newly transmitted by a terminal can be provided.

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

1 is a diagram illustrating a wireless communication system to which the present disclosure is applied.
2 shows an example of a frame structure to which different memorylogies are applied.
3 is a diagram for explaining a mapping relationship between a QoS flow and a data radio bearer.
4 is a diagram illustrating a dual-link (DC) structure to which the present disclosure may be applied.
5 is a diagram illustrating a carrier merging (CA) structure to which the present disclosure may be applied.
6 is a diagram illustrating PDCP copy deactivation and activation associated with this disclosure;
7 is a diagram for explaining a PDCP copy operation for uplink data in a DC structure related to the present disclosure.
8 is a view for explaining an example of the PDCP copy operation according to the present disclosure.
Figure 9 is an illustration of an example of a MAC CE format that directs PDCP replication activation according to the present disclosure.
10 is a diagram for illustrating a further example of a PDCP copy operation according to the present disclosure.
11 is a diagram illustrating a further example of a MAC CE format that directs PDCP replication activation according to the present disclosure.
12 is a diagram for explaining a further example of the PDCP copy operation according to the present disclosure.
13 is a flowchart for explaining the PDCP copy activation operation according to the present disclosure.
14 is a diagram showing a configuration of a base station apparatus and a terminal apparatus according to the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, which will be easily understood by those skilled in the art. However, the present disclosure may be embodied in many different forms and is not limited to the embodiments described herein.

In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear. Parts not related to the description of the present disclosure in the drawings are omitted, and like parts are denoted by similar reference numerals.

In the present disclosure, when an element is referred to as being "connected", "coupled", or "connected" to another element, it is understood that not only a direct connection relationship but also an indirect connection relationship May also be included. Also, when an element is referred to as " comprising "or" having "another element, it is meant to include not only excluding another element but also another element .

In the present disclosure, the terms first, second, etc. are used only for the purpose of distinguishing one element from another, and do not limit the order or importance of elements, etc. unless specifically stated otherwise. Thus, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly a second component in one embodiment may be referred to as a first component .

In the present disclosure, the components that are distinguished from each other are intended to clearly illustrate each feature and do not necessarily mean that components are separate. That is, a plurality of components may be integrated into one hardware or software unit, or a single component may be distributed into a plurality of hardware or software units. Thus, unless otherwise noted, such integrated or distributed embodiments are also included within the scope of this disclosure.

In the present disclosure, the components described in the various embodiments are not necessarily essential components, and some may be optional components. Thus, embodiments consisting of a subset of the components described in one embodiment are also included within the scope of the present disclosure. Also, embodiments that include other elements in addition to the elements described in the various embodiments are also included in the scope of the present disclosure.

In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal connected to the network.

That is, it is apparent that various operations performed for communication with a terminal in a network composed of a plurality of network nodes including a base station can be performed by a network node other than the base station or the base station. A 'base station (BS)' may be replaced by a term such as a fixed station, a Node B, an eNode B (eNB), an access point (AP) In addition, 'terminal' may be replaced with terms such as User Equipment (UE), Mobile Station (MS), Mobile Subscriber Station (MSS), Subscriber Station (SS) .

1 is a diagram illustrating a wireless communication system to which the present disclosure is applied.

The network structure shown in FIG. 1 may be a network structure of an Evolved-Universal Mobile Telecommunications System (E-UMTS). The E-UMTS system includes a LTE (Long Term Evolution), an LTE-A (advanced), an LTE-A pro system and an evolved-LTE system, or a 5G mobile communication network, a 5G ), And the like.

Referring to FIG. 1, a base station (BS) and a user equipment (UE) 12 in a wireless communication system 10 can transmit and receive data wirelessly. Also, the wireless communication system 10 may support D2D (Device to Device) communication.

In the wireless communication system 10, the base station 11 can provide a communication service through a specific frequency band to terminals existing within the coverage of the base station. The coverage served by the base station may also be expressed in terms of a site. A site may include a plurality of areas 15a, 15b, 15c, which may be referred to as sectors. Each of the sectors included in the site can be identified based on different identifiers. Each of the sectors 15a, 15b, and 15c can be interpreted as a partial area covered by the base station 11.

The base station 11 generally refers to a station that communicates with the terminal 12 and includes an evolved NodeB (eNodeB), a gNB (g-NodeB or 5G-NodeB), a base transceiver system (BTS) A femto base station (Femto eNodeB), a home base station (HeNodeB), a relay, a remote radio head (RRH), and the like.

The terminal 12 may be fixed or mobile and may be a mobile station, a mobile terminal, a user terminal (UT), a subscriber station (SS), a wireless device, a personal digital assistant (PDA) , A wireless modem, a handheld device, a connected car, a wearable device, an Internet of Things device, and the like.

The base station 11 may also be referred to as various terms such as megacell, macrocell, microcell, picocell, femtocell, etc. depending on the size of the coverage provided by the base station and / . A cell may be used in terms of a frequency band provided by the base station, coverage of the base station, a beam embodied by the antenna of the base station, or a term indicating the base station. Also, when one terminal is connected to two or more base stations at the same time, such as dual connectivity or multi connectivity, the terminals may be called different terms depending on the role of each base station as follows. For example, a base station capable of directly controlling signaling for radio resource control for the MS and controlling mobility and radio connection such as handover is a master eNodeB, and provides additional radio resources to the MS A base station that can control some of the radio resources in some independent manner and some can proceed through the primary base station may be referred to as secondary eNodeB.

Downlink refers to communication or communication path from the base station 11 to the terminal 12 and uplink refers to communication from the terminal 12 to the base station 11 Communication path ". In the downlink, the transmitter may be part of the base station 11, and the receiver may be part of the terminal 12. In the uplink, the transmitter may be part of the terminal 12, and the receiver may be part of the base station 11.

On the other hand, there is no limitation in the multiple access technique applied to the wireless communication system 10. [ For example, a CDMA (Code Division Multiple Access), a TDMA (Time Division Multiple Access), an FDMA (Frequency Division Multiple Access), an OFDMA (Orthogonal Frequency Division Multiple Access), an SC- , OFDM-TDMA, OFDM-CDMA, frequency hopping (FH) -CDMA, and FH-OFDMA. In the uplink transmission and the downlink transmission, a time division duplex (TDD) scheme, a frequency division duplex scheme (FDD) scheme using different frequencies, And a half-FDD scheme in which link transmission and downlink transmission are performed using different times.

The abbreviations used in this disclosure are defined as follows.

- TTI: Transmission Time Interval

- RRC: Radio Resource Control

- MAC: Media Access Control

- RLC: Radio Link Control

- PDCP: Packet Data Convergence Protocol

- SDAP: Service Data Adaptation Protocol

- PBR: Prioritized Bit Rate

- PDU: Packet Data Unit

- SDU: Service Data Unit

- DRB: Data Radio Bearer

- eMBB: evolved Mobile BroadBand

- URLLC: Ultra Reliability Low Latency Communication

- mMTC: massive Machine Type Communication

- QoS: Quality of Service

- QFI: QoS Flow Identifier

- NDI: New Data Indicator

- RV: Redundancy Version

Different types of services (eg, realistic content, mobile holographic display, smart home service, etc.) required for a next generation mobile communication system can be largely classified into three service types, eMBB, URLLC, and mMTC. The requirements for supporting the above three service types may include various items, and the same requirement items must satisfy different criteria according to the service type.

For example, with respect to the requirement item for the latency, in the case of the eMBB service, data conforming to various types and purposes may have different reliability for each channel through which the data is transmitted. For example, there may be various criteria such as 1%, 0.01%, or 0.001% error rate for data with different QoS. For example, regarding the delay time occurring in the unidirectional communication between the second layer (layer 2) and the second layer (layer 2) in the terminal based on the above reliability, in the case of the eMBB service, In case of the URLLC service, it may be required that the delay time is 0.5 ms or less.

In order to satisfy various requirement criteria, the unit of radio resources defined as time, frequency, and space, which is the basic unit of the physical channel, can have a great influence. In the case of the delay time as described above, the delay time becomes longer as the amount of the time resource unit becomes larger when one radio resource is defined. Particularly, in the case of a time resource unit for transmitting a single MAC PDU like a TTI, the length of the TTI greatly influences the delay time when designing a frame structure for a physical channel and a radio resource because it is a time necessary for data transmission.

The numerical value used to define the operation of a wireless communication system is referred to as numerology. Specifically, the definition of a frequency bandwidth of a subcarrier, a cyclic prefix (CP) length in an information symbol such as an OFDM symbol, and the like may be referred to as a neuroregion, a TTI may be referred to as a neighbility, The numerical value of the frequency resource unit standard may be referred to as a numerical value or the numerical value of the time and / or frequency resource unit standard for the TTI and the radio communication may be collectively referred to as a numerical value. The frequency bandwidth of the subcarrier may be defined as a subcarrier interval.

In the NR system under discussion as one of the next generation mobile communication systems, a frame structure including at least two or more different neighbors can be introduced.

2 shows an example of a frame structure to which different memorylogies are applied.

In FIG. 2, it is shown that different types of radio signals are defined for different radio resources. The orthogonal frequency division multiplexing (OFDM) symbol interval and the sub carrier bandwidth may be different from each other and the TTI lengths may be different from each other.

In the example of FIG. 2, a time-frequency resource configuration according to three different memorylogories is exemplarily shown.

The resource configuration unit of the NR system in the case where the journal number # 1 210 is applied can be defined by the TTI # 1 212, the OFDM symbol length # 1 214 and the subcarrier interval # 1 216 .

The resource unit of the NR system in the case where the second system 220 is applied can be defined by the TTI # 2 222, the OFDM symbol length # 2 224, and the subcarrier interval # 2 226 . For example, TTI # 1 212 may be twice as long as TTI # 2 222, OFDM symbol length # 1 214 may be twice as long as OFDM symbol length # 2 224, The subcarrier interval # 1 (216) may be half the subcarrier interval # 2 (226).

The resource configuration unit of the NR system in the case where the neural network # 3 230 is applied can be defined by the TTI # 3 232, the OFDM symbol length # 3 234 and the sub-carrier interval # 3 236 . For example, TTI # 1 212 may be four times as long as TTI # 3 232, OFDM symbol length # 1 214 may be four times as long as OFDM symbol length # 3 234, The subcarrier interval # 1 216 may be a quarter of the subcarrier interval # 3 236.

As described above, the length of a period of the OFDM symbol interval between the neurons can be always ²ⁿ (n is a natural number) times. However, in the case of the TTI, an example of the relation of ²ⁿ (n is a natural number) is shown in Fig. 2, but other relations are also possible. For example, some of the sections shown as TTI # 1 (212), TTI # 2 (222), and TTI # 3 (232) in FIG. 2 may correspond to the actually defined TTI length.

The base station can provide information on the DL and UL that can be supported by the corresponding base station in a system information message provided in a broadcast format within the cell. Such a demodulation indication information may include components such as TTI, subcarrier frequency bandwidth, slot length, mini-slot support, and the like. Further, the program information may be signaled in the form of presetting one or more set candidates of the components and indicating the index of one of the set candidates.

Defining multiple neighbors that can support various QoSs in the physical layer, based on this, the RAN (radio access network) slicing, a concept of logically separating and managing each radio resource in the radio access protocol layer, We are in discussion.

To distinguish from RAN slicing, devices based slicing in the core network (CN) is referred to as CN slicing. CN slicing refers to a method of operating separately to support a specific QoS by logically dividing network resources constituted by core network devices existing between an external Internet network and base stations in a specific TA (Tracking area). To this end, core network devices may include virtual devices defined in software form, and may be changed to completely different devices by updating or replacing software. In addition, network resources or paths required to support a specific QoS may be changed in real time through software.

First, a method for setting up a radio bearer based on QoS on a base station and a method for performing a reflective QoS operation for uplink data transmission in a mobile station will be described.

3 is a diagram for explaining a mapping relationship between a QoS flow and a data radio bearer.

The base station sets up a radio bearer based on the QoS value of data to be serviced or generated by the UE for uplink transmission of each UE. The radio bearer may be configured for transmission or reception of data packets having a specific QoS. Thus, data packets with different QoS are transmitted or received via different radio bearers. A bearer set for transmitting data among the radio bearers is called a data radio bearer (DRB).

The DRB has a one-to-one mapping relationship with one logical channel (LC). The base station can set a corresponding LC when setting the DRB. The LC setting information may include a logical channel ID (LCID), a DRB ID corresponding to the corresponding LC, and may further include information about a logical channel group (LCG) to which the corresponding LC is to be included.

Each of the packets (e.g., PDUs) transmitted from the core network to the radio access network (RAN) through the PDU session has a QoS flow ID value. Specifically, various QoS flows can be transmitted over a particular PDU session, and each of the various QoS flows can have a QoS flow ID. Here, the DRB to which each packet is to be transmitted may be determined based on the QoS flow ID. That is, a mapping relationship or a routing relationship between the QoS flow ID and the DRB can be set. Specifically, a routing relationship or a mapping relationship between a specific QoS flow and a DRB among a single QoS flow or various QoS flows transmitted through a specific PDU session in a layer called SDAP (Service Data Adaptation Protocol) can be established.

In the example of FIG. 3, for various QoS flows received through the NG-U reference point 305, the QoS flow 310 in which the value of the QoS flow ID in the SDAP layer 340 corresponds to QoS # 1 is DRB # K 312 corresponding to the QoS # 2 is mapped to the DRB # L 322 and the QoS flow 330 corresponding to the QoS # 3 is mapped to the DRB # .

The SDAP layer 340 also stores the QoS flow ID value for each packet in a data packet that is transmitted from the SDAP to the Packet Data Convergence Protocol (PDCP) layer 314, 324, 334 (e.g., Header) in the header.

The DRCP layers 314, 324 and 334 and the Radio Link Control (RLC) layers 316, 326 and 336 are set for each of the DRBs 312, 322 and 332, And may be processed by the common MAC layer 350.

Accordingly, the UE can confirm the QoS flow ID of the PDU received through the specific DRB in the downlink (DL), and determine the QoS flow ID that the UE can transmit on the uplink (UL) through the corresponding DRB (I. E., Reflective QoS operation). In addition, when uplink transmission of data generated by the UE is performed, it is determined based on the QoS flow ID that a certain DRB can be transmitted to the access layer (AS).

To more specifically describe the reflexive QoS operation, the UE can grasp the QoS for the corresponding DRB based on the QoS flow ID included in the data packet received through the specific DRB set in the UE. Also, the UE can transmit the uplink data packet through the DRB when the QoS flow ID included in the uplink data packet generated in the UE matches the QoS flow ID mapped to the DRB for which the QoS is grasped .

Also, the UE can recognize the mapping relationship between the uplink QoS flow and the DRB through the RRC connection reconfiguration message received from the base station.

Among the above-described methods of using the reflex QoS operation method and the method using the RRC connection re-establishment message, the UE can follow the latest information.

Also, if the UE can not know the mapping relationship between the QoS flow ID of the uplink data packet and the DRB, the UE can transmit the uplink data packet through the default DRB.

The PDCP layer performs a header compression function that reduces unnecessary information to efficiently transmit data packets transmitted to the DRB, and performs a data packet reordering and a redundant data packet detection function. In addition, the PDCP layer performs security and RRC connection It performs the function of retransmitting the data packet which is not properly received at the receiver at the time of reset. In the NR system, PDCP duplication (Duplication), which is a new function of the PDCP layer, has been added and is under discussion.

In this disclosure, PDCP replication, which is a new function of the PDCP layer, and data packet reordering and duplicate data packet detection functions that can be applied in performing PDCP replication will be described.

PDCP duplication refers to a method in which data packets are copied and transmitted to different RLC layers at the PDCP layer of the transmitter. According to the PDCP replication function discussed so far, when a Dual Connectivity (DC) structure or a Carrier Aggregation (CA) structure is set for a UE, PDCP duplication is performed for an uplink data packet having a specific QoS flow ID. .

4 is a diagram illustrating a dual-link (DC) structure to which the present disclosure may be applied.

DC means an operation in which a terminal can be concurrently connected to a master base station and a secondary base station. In the example of FIG. 4, a UE having a DC configuration may have a hierarchical structure 450 of a hierarchical structure 410 of a master base station and a hierarchical structure 460 of a hierarchical structure 420 of a subordinate base station Is shown illustratively.

A UE having a DC set up is connected to a MAC entity 453 for a MCG (Master Cell Group) serving as a group of serving cells related to a master base station and a MAC entity 463 for a secondary cell group (SCG) As shown in FIG.

In the hierarchical structure 450 corresponding to the master base station, the UE can process the data packet to be transmitted through the MCG bearer through the PDCP 451-1 and the RLC 452-1 and transmit the processed data packet to the MAC entity 453 . The data packet received from the UE in the hierarchical structure 410 of the master base station is transmitted to the PDCP entity 411-1 via the MAC entity 413 and the RLC 412-1 and the data packet is mapped to the MCG bearer .

In the hierarchical structure 460 corresponding to the auxiliary base station, the UE can process the data packet to be transmitted through the SCG bearer through the PDCP 461 and the RLC 462-2 and transmit the processed data packet to the MAC entity 463. The data packet received from the UE in the hierarchical structure 420 of the auxiliary base station is transmitted to the PDCP entity 421 via the MAC entity 423 and the RLC 422-2 and the data packet can be mapped to the SCG bearer .

Also, the terminal may use both the resources of the master base station and the auxiliary base station using a split bearer scheme.

For example, the UE replicates data packets to be transmitted through the split bearer through the PDCP entity 451-2, and transmits the duplicated data packets to the RLC 452-2 corresponding to the master base station and the auxiliary base station To the RLC 462-1, which may be communicated to the MAC 453 and the MAC 463, respectively.

The data packet received from the MS in the hierarchical structure 410 of the master base station is transmitted to the PDCP entity 411-2 via the MAC entity 413 and the RLC entity 412-2, The data packet received from the terminal can be transmitted to the PDCP entity 411-2 of the master base station via the MAC entity 423 and the RLC entity 422-1.

In this manner, in the DC structure, data packets corresponding to two MAC entities can be merged or separated into one through a PDCP entity. In the example of FIG. 4, the PDCP entity processing the split bearer is shown as belonging to the MCG, but the present invention is not limited thereto, and the PDCP entity may belong to the SCG.

5 is a diagram illustrating a carrier merging (CA) structure to which the present disclosure may be applied.

A CA is a combination of two or more component carriers (CCs) or cells in order to support a wide transmission bandwidth. Depending on the capability of a terminal, a CA can transmit or receive data packets simultaneously using one or more CCs have.

And may have one single MAC entity 523 in the hierarchical structure 520 of the CA where the CA is established. In the NR system, a split bearer scheme may be supported in the CA to support PDCP replication. The split bearer in the CA duplicates a data packet in one PDCP entity 521 and uses two RLC entities 522-1 and 522-2 to transmit different carriers (e.g., carrier x, carrier y) Lt; RTI ID = 0.0 > of < / RTI > the two carriers. In the hierarchical structure 510 of the base station, RLCs 512-1 and 512-2 corresponding to respective carriers (for example, carrier x and carrier y) corresponding to data packets received from the terminal via the MAC 513, To the PDCP entity 511 through the PDCP entity 511.

In performing PDCP replication, the UE transmits the same packet to different base stations through different MAC entities in the case of DC, and transmits the same packet to different carriers through one MAC entity in case of CA, The reliability is increased and the delay time is reduced. Therefore, PDCP replication is applied to data packets requiring high reliability such as URLLC.

When the PDCP replication as described above is performed, the PDCP layer of the receiving end can process the duplicated data without any problem through the function of detecting the duplicated data packet and the data packet reordering function. This function is possible because PDCP allocates SN (Sequence Number) for each data packet when processing data.

Specifically, the PDCP layer checks the SN of the received data packet, and when the SN is the same SN, the PDCP layer can detect the overlapped data packet by considering it as an overlapped data packet. In addition, the data packets may be rearranged in the order of the SNs, and the data packets may be sequentially transmitted to the upper layer. The data packet reordering is performed for a predetermined time defined by a predetermined timer (for example, a t-reordering timer). When the timer expires, the data packet is delivered to the upper layer without any further waiting . Therefore, even if the PDCP layer of the receiving end receives the PDCP replicated data packet, the PDCP layer of the receiving end can process the duplicated packet without any problem through the redundancy detection function and the reordering function. In addition, security may be applied to each data packet using the SN.

The base station can decide to activate or deactivate PDCP replication with a few considerations. The above consideration may be the uplink channel environment between the UE and the BS, the load situation of the cell or the carrier, and the packet size. Therefore, if the uplink channel environment of the UE is bad or the cell or carrier can sufficiently process the packet even if the UE receives the duplicated packet, or if the UE determines that the packet size to be transmitted is not small, When one or more conditions are satisfied at the same time, it is possible to increase the data packet reception probability of the base station by activating the PDCP replication. The base station may deactivate PDCP replication if one or more of the above conditions are not satisfied.

The base station can indicate whether the PDCP replicas are available to the terminal through the RRC message and instruct the terminal to activate or deactivate the PDCP replicant through a MAC Control Element (CE). At this time, the MAC CE may be configured in the form of a bitmap. For example, a DRB corresponding to each bit of the bitmap is defined, and it is possible to indicate whether to activate the PDCP copy for the corresponding DRB according to the bit value. The UE can perform PDCP replication only on the activated DRB and the QoS flow ID having a mapping relationship with the DRB. Thereafter, the UE performs PDCP replication in the DRB in which the PDCP replication is activated.

6 is a diagram illustrating PDCP copy deactivation and activation associated with this disclosure;

The SDAP layer of the terminal can map to the DRB according to the QoS flow ID when an IP packet to be transmitted arrives. In the example of FIG. 6, in the PDCP duplication disabled state, the UE can map to the default DRB when the DRB mapped to the QoS flow ID 1 is unknown. Also, the UE can map QoS flow IDs 2 and 3 to DRB A, QoS flow ID 4 to DRB B, and QoS flow ID 5 to DRB C. Accordingly, a data packet to be transmitted corresponding to each DRB is configured in the SDAP layer in the form of SDAP PDUs and is transmitted to the PDCP layer. In the PDCP layer, a PDCP PDU can be generated and transmitted to the corresponding RLC layer.

In the example of FIG. 6, even in the case of the URLLC data packet, the UE can not arbitrarily apply the PDCP replica and can process the PDCP PDU without duplication.

The BS can decide to activate PDCP replication for data packets requiring high reliability and low delay considering the uplink channel environment of the UE, the packet size transmitted by the UE, and the load status of the cell or the carrier. The data packet to which the PDCP replication is applied may be, for example, a URLLC data packet. After that, the base station can identify the DRB to which the corresponding data packet is transmitted, configure the MAC CE, and transmit it to the mobile station.

As shown in FIG. 6, when a URLLC data packet has a mapping relation with DRB B, the base station can indicate to activate the DRB B through the MAC CE configured as a bitmap, and transmit the DRB B to the terminal. The UE receiving the MAC CE can perform PDCP replication on the SDAP PDU transmitted in DRB B.

In the example of FIG. 6, in response to an instruction from the base station, the UE can set PDCP replication activation for DRB B mapped to QoS flow ID 4 corresponding to the URLLC data packet. Accordingly, in the PDCP layer corresponding to the DRB B, two identical data packet PDCP PDUs are generated in duplicate (for example, SN values contained in two PDCP PDU packets are the same) have.

7 is a diagram for explaining a PDCP copy operation for uplink data in a DC structure related to the present disclosure.

In the following description, the SDU means a packet which has arrived at the layer but has not yet been processed in the layer, and the PDU means a packet processed by applying the function of the layer in the layer. For example, an RLC PDU refers to a data packet in which a data packet is divided according to a data size requested by a lower layer in an RLC layer and an RLC header is added. The MAC SDU includes an RLC PDU transmitted from the RLC layer, And a data packet that has not yet been processed by the MAC layer.

7, when an IP packet 710 corresponding to an uplink data packet to be transmitted to a base station is transmitted to the SDAP 720, the SDAP 720 transmits, based on the QoS flow ID and the DRB mapping relationship of the IP packet 710 IP packet 710 may determine the DRB to which it will be forwarded. Here, it is assumed that PDCP replication is activated for the DRB corresponding to the QoS flow ID of the IP packet 710 according to an instruction from the base station. Accordingly, the SDAP 720 may generate an SDAP PDU 725 based on the IP packet 710 and may forward it to the PDCP 730 corresponding to the DRB mapped to the QoS flow ID.

The PDCP 730 can duplicate two PDCP PDUs 735-1 and 735-2 having the same SN value (e.g., n) as the PDCP replication is activated. The generated PDCP PDUs 735-1 and 735-2 may be delivered to respective RLCs 740-1 and 740-2.

The RLC 740-2 receiving the PDCP PDU 735-1 and the PDCP PDU 735-2 receiving the PDCP PDU 735-1 can process data according to each RLC mode. The RLC layer can support three modes such as RLC-TM (Transport Mode), RLC-UM (Unacknowledged Mode) and RLC-AM (Acknowledged Mode) to guarantee various QoS required by each radio bearer. In case of RLC-TM, it transfers the received RLC SDU (ie PDCP PDU) to the MAC layer as it is. In case of RLC-UM and RLC-AM, after dividing the PDCP PDU according to the packet size indicated in the lower layer, SN is allocated, and the RLC header is added. Then, the RLC PDU is generated and transmitted to the MAC layer. Here, in the structure in which PDCP replication is applied, only the RLC-AM mode can be supported.

Since the replicated PDCP PDUs 735-1 and 735-2 having the same SN are transmitted to the different RLCs 740-1 and 740-2, the RLC PDUs 740-1 and 740-2 in each RLC 740-1 and 740-2 745-1 and 745-2) may be different from each other. For example, the SN value of the RLC PDU 745-1 allocated by the RLC 740-1 may be x, and the SN value of the RLC PDU 745-2 allocated by the RLC 740-2 may be y Lt; / RTI > Alternatively, SN values allocated by different RLCs may be the same. Since the SN allocated by the RLC layer is identified and processed only in the RLC layer, it is distinguished from the SN allocated in the PDCP layer and does not affect each other. Therefore, the PDCP layer 780 of the receiving end can detect duplicated packets through the SN allocated by the PDCP layer 730 of the transmitting end.

The MAC layers 750-1 and 750-2 that have received the RLC PDUs 745-1 and 745-2 generate MAC PDUs 755-1 and 755-2 and perform HARQ (Hybrid Automatic Repeat reQuest) To the base station. HARQ is an automatic repeat and retransmission for reliable transmission of data. The HARQ function is applied when a mobile station transmits an uplink data packet to a base station, and the base station correctly receives the uplink data packet transmitted from the mobile station , It notifies by notifying the NDI (New Data Indicator) with the transmission of the HARQ process ID. In addition, when the Node B fails to correctly receive the uplink data packet transmitted by the UE, the Node B does not toggle the NDI together with the HARQ process ID, UL grant, and RV (Redundancy Version) transmission, And request retransmission.

The base station receiving the MAC PDUs 755-1 and 755-2 transmitted by the UE may forward the MAC SDUs 765-1 and 765-2 to the RLC layers 770-1 and 770-2. The RLC layers 770-1 and 770-2 can perform the ARQ (Automatic Repeat reQuest) function by applying the RLC-AM mode. The ARQ is a request for retransmission of a packet that has not been received due to a failure of HARQ in the MAC layer. The RLC layer of the transmitting end, which has requested retransmission, retransmits the data packet.

The RLC layers 770-1 and 770-2 can forward the received RLC SDUs 775-1 and 775-2 to the PDCP layer 780. [ Upon receiving the RLC SDUs 775-1 and 775-2 from the different RLC layers 770-1 and 770-2, the PDCP layer 780 checks the SN allocated by the PDCP layer 730 of the transmitting end, And perform data packet reordering to process the data packet.

For example, if the PDCP 780 receives two duplicate data packets having the SN value equal to n, the PDCP 780 may discard one and generate the other PDCP SDU 785 as a PDCP SDU 785 and transmit the PDCP SDU 785 to the SDAP 790 . The SDAP 790 processes the data packet transmitted from the PDCP 780 and constructs the data packet as an IP packet 795 to be transmitted to the upper layer.

In connection with the above-described PDCP replication operation, when the UE desires to transmit a new data packet, a new QoS flow ID for the corresponding data packet may be set. For a new QoS flow ID, which DRB is mapped may not yet be set. In this case, when the UE transmits a data packet having no mapping relationship between the QoS flow ID and the DRB, the UE can be defined to transmit through the default DRB.

It is assumed that a new data packet to be transmitted by the terminal is a URLLC data packet requiring high reliability. The NR system can set up PDCP replication for a specific DRB to support the high reliability required by URLLC data packets. The PDCP replication discussed so far can be activated or deactivated for a specific DRB that is mapped to a specific QoS flow ID and a scheme for instructing activation or deactivation of PDCP replication for a default DRB that is not mapped to the QoS flow ID It is not prepared.

In this manner, when the UE desires to transmit a new URLLC data packet, a new QoS flow ID may be set in the data packet. In this case, there may be no mapping relationship between the QoS flow ID and the DRB. At this time, the UE must transmit the URLLC data packet in the default DRB. Therefore, the UE must transmit the URLLC data packet to the base station without performing the PDCP replication even though the PDCP replication is required to satisfy the high reliability. In this case, a problem may occur in reception of the uplink data packet at the base station.

Therefore, in the present disclosure, when a UE performs PDCP replication for reliable transmission of an uplink data packet, there is a problem that can occur when a data packet requiring PDCP replication does not have a mapping relationship with a DRB activated with PDCP replication A method for solving the problem will be described.

Example  One

The present embodiment is directed to allowing PDCP replication for the second type DRB when PDCP replication for at least one first type DRB is activated.

DRBs may include a first type DRB that is mapped to a QoS flow ID and a second type DRB that is not mapped to a QoS flow ID (e.g., a default DRB). Each of the first type DRBs may be mapped to one or more QoS flow IDs. The second type DRB can be used when the mapping relationship between the QoS flow ID and the DRB is not determined.

For example, if activation of PDCP replication for one or more of the first type DRBs is determined, the base station may transmit the MAC CE to instruct the terminal to activate PDCP replication. Here, the base station may further include, in the MAC CE indicating the activation of the PDCP replication for at least one of the first type DRBs, information for instructing activation of the PDCP replication for the second type DRB.

If none of the first type DRBs indicate that PDCP replication activation is indicated, the base station may not indicate PDCP replication activation for only the second type DRB. That is, for the second type DRB, PDCP copy activation may be instructed simultaneously with the first type DRB.

Alternatively, if there is at least one DRB whose PDCP replication has already been activated among the first type DRBs, the second type DRB may be instructed to activate PDCP replication. That is, even if signaling is not performed simultaneously with the PDCP copy activation instruction for the first type DRB, if the PDCP copy for the first type DRB is already activated, the PDCP copy activation instruction for the second type DRB alone may be signaled.

8 is a view for explaining an example of the PDCP copy operation according to the present disclosure.

In the example of FIG. 8, DRB A, DRB B and DRB C correspond to a first type DRB, and default DRB corresponds to a second type DRB.

For example, when the base station decides to activate PDCP replication for the DRB B corresponding to the first type DRB, it can transmit a MAC CE including information (e.g., a bitmap) indicating the PDCP to the terminal . Herein, when the PDCP replication for one or more DRBs of the first type DRB is activated, the base station may transmit the information including the indication to activate the PDCP replication for the second type DRB in the MAC CE together.

For example, the base station may decide to activate PDCP replication based on the uplink channel environment of the terminal, the size of the uplink data packet, the load status of the cell or the carrier. Therefore, the base station grasps the QoS flow ID for the URLLC data packet, identifies the DRB having a mapping relationship with the QoS flow ID, configures the MAC CE to activate PDCP replication in the corresponding DRB, and transmits the MAC CE to the terminal .

Figure 9 is an illustration of an example of a MAC CE format that directs PDCP replication activation according to the present disclosure.

The MAC CE indicating the PDCP replication activation may have a variable length of 8 bits, 16 bits, 24 bits, 32 bits, 40 bits, 48 bits, 56 bits or 64 bits depending on the total number of configured DRBs. 9A is a diagram showing an example of configuring an 8-bit MAC CE for the four DRBs configured. The number of DRBs can be determined according to the QoS of the service supported by the communication system. Therefore, with the increase of diverse services such as eMBB, URLLC, and mMTC, a total of 64 DRB indexes can be supported, from 0 to 31, for a total of 32 or 0 to 63.

When the total number of configured DRBs is 8 or less, 8-bit MAC CEs are used. If the total number of configured DRBs is 9 or more and 16 or less, 16-bit MAC CEs can be used. Similarly, if the total number of configured DRBs is 17 or more and 24 or less, a 24-bit MAC CE is used. If the total number of configured DRBs is 25 or more and 32 or less, a 32-bit MAC CE is used. Also, if the total number of configured DRBs is more than 33 and not more than 40, a 40-bit MAC CE is used. Similarly, a 48-bit, 56-bit MAC CE may be used, depending on the total number of configured DRBs, and a 64-bit MAC CE may be used if the total number of configured DRBs is greater than 57.

The DRB having the highest index is mapped to the least significant bit (LSB), and the DRB having the next highest index is mapped to the bit before the mapped bit. Therefore, it is filled in from the least significant bit, and the DRB having a small index is mapped to an upper bit. The default DRB may be mapped to the bit preceding the mapped bit of the DRB with the smallest index.

Or the default DRB is mapped to the least significant bit (LSB) of the MAC CE and the DRB with the highest index can be mapped before the default DRB. The DRB having the next highest index is mapped to the bit before the mapped bit, and thus the DRB having the small index is mapped to the higher bit.

Or may be mapped to bits in the order of the index of the DRB, without setting the location of the default DRB separately.

If the total number of configured DRBs is not 8, 16, 32, or 64, the upper bits are empty. In this case, the remaining bits are reserved bits in order from the most significant bit, . Therefore, in the example in which the four DRBs of the default DRB, DRB A, DRB B, and DRB C are configured, when the index A, B, and C have a relationship of A <B <C, The bitmap value may be 00000010. Or if the default DRB is mapped to the LSB, the bitmap value of the MAC CE may be 00000100. The bitmap value of the MAC CE may also be 00000010 if X <A <B <C, where X is the index of the default DRB, considering the index of the default DRB.

In this case, when the DRB B corresponding to the first type DRB is activated, the base station can simultaneously determine to activate the second type DRB (i.e., the default DRB). Accordingly, the bitmap value of the MAC CE can be configured as 00001010. Or if the default DRB is mapped to the LSB, the bitmap value of the MAC CE may be 0000101.

The UE receiving the MAC CE configured as described above can perform data packet replication in the PDCP layer for SDAP PDUs transmitted in the corresponding DRBs (for example, DRB B and default DRB).

At this time, if PDCP replication is instructed to one or more DRBs, a DRB to which PDCP replication is performed may always include a default DRB.

9B, the MAC CE indicating the activation of the PDCP duplication may be 8 bits, 16 bits, 24 bits, 32 bits, 40 bits, 48 bits, 56 bits, or 16 bits according to the index value of the DRB configured in the UE It can have a variable length of 64 bits. The number of DRBs can be determined according to the QoS of the service supported by the communication system. Therefore, with the increase of diverse services such as eMBB, URLLC, and mMTC, a total of 64 DRB indexes can be supported, from 0 to 31, for a total of 32 or 0 to 63.

Also, FIG. 9 (b) shows a structure in which each DRB is mapped to one bit in the MAC CE for activation / deactivation of PDCP duplication according to an index value. When the index of DRB is i, each DRB can be represented by DRB _i according to the index value. If the DRB corresponding to the index value i configuration, the DRB _i may be mapped to a single bit in the MAC CE, may be based on the value of the bit indicates whether to enable or disable for each of the DRB _i. The indicate the activation of the DRB _i, bits in the MAC CE for enabling / disabling PDCP clone that corresponds to the DRB _i is set to 1, indicate the disabled, for enabling / disabling PDCP clone that corresponds to the DRB _i The bit in MAC CE may be set to zero. DRBs with index 0 (i.e., DRB ₀ ) are mapped to LSBs and can be mapped to higher order bits in the order of increasing index i. At this time, the default DRB can be mapped to bits according to the index order of the default DRB. 9 (b) shows an example of a MAC CE configured based on the above description.

When the index of the configured DRB is not larger than 7, the 8-bit MAC CE is used. If the index of the configured DRB is larger than 7 and not larger than 15, the 16-bit MAC CE can be used. Likewise, if the index of the configured DRB is greater than 15 and not greater than 23, a 24-bit MAC CE is used, and 32 bits, 40 bits, 48 bits, or 56 bits may be used, depending on the index value of the configured DRB. If the configured DRB index is greater than 55, a 64-bit MAC CE may be used. When the above configuration is applied, the bit for the DRB index not configured in the corresponding terminal is always set to zero.

Therefore, in the example in which four DRBs of the default DRB, DRB A, DRB B, and DRB C are configured, if the index of the default DRB is 1, the index of DRB A is 2, the index of DRB B is 3, and the index of DRB C is 4 , The bitmap value of the MAC CE indicating that DRB B is activated may be 00001000.

In this case, when the DRB B corresponding to the first type DRB is activated, the base station can simultaneously determine to activate the second type DRB (i.e., the default DRB). Accordingly, the bitmap value of the MAC CE can be configured as 00001010.

The UE receiving the MAC CE configured as described above can perform data packet replication in the PDCP layer for SDAP PDUs transmitted in the corresponding DRBs (for example, DRB B and default DRB).

Similarly, if PDCP replication is instructed to one or more DRBs at this time, a DRB to which PDCP replication is performed may always include a default DRB.

The SDAP layer of the MS transmits to the DRB having a mapping relationship according to the QoS flow ID of the data packet, and the data packet having the QoS flow ID (for example, QoS flow ID 1) that is not mapped to the DRB is transmitted to the DRB . SDAP PDUs transmitted in the default DRB and DRB B can perform data packet replication by allocating the same SN in the PDCP layer. The data packet transmitted to the DRB B may be URLLC data. When the UE desires to transmit a URLLC data packet having a new QoS flow ID, a default DRB is generated even if the QoS flow ID of the data packet does not have a mapping relation with the DRB B. PDCP replication can be performed by using the PDCP protocol.

The replicated PDCP PDUs are transmitted to different RLC layers. In the RLC layer, RLC-AM mode is applied to divide data packets according to the requested data size in the lower layer, and RLC header can be added to the MAC layer . The MAC layer receiving the RLC PDU can transmit MAC PDUs to different base stations or different carriers through the HARQ function.

The MAC layer of the BS receiving the uplink data packet of the UE transfers the MAC SDU to the RLC layer, and the RLC layer can perform the ARQ function on the data packet not received by applying the RLC-AM mode. Thereafter, the RLC SDU received by the RLC layer can be transmitted to the PDCP layer. In this case, when all the duplicated data packets are successfully transmitted, the PDCP layer of the base station receives replicated PDCP PDUs having the same SN from different RLC layers. The PDCP layer detects redundant data packets through the SN allocated to the PDCP PDU, stores only one data packet in the buffer, and processes the data packet by arranging the data packets in order and transferring them to the upper layer.

Here, if PDCP replication is always activated for the default DRB, PDCP replication can be applied to data packets that do not require PDCP replication. In this case, the base station transmits a QoS flow ID for the corresponding data packet to the DRB (DRB A or DRB C) for which PDCP replication is not activated through a reflective QoS scheme or an RRC connection reconfiguration message, It is possible to prevent unnecessary PDCP replication from being performed.

The BS can not grasp all of the QoS flow IDs of uplink data packets to be transmitted by the MSs (in particular, data packets to be newly transmitted by the MS). Therefore, even if the PDCP replication is activated for the reliable transmission of data, the PDCP replication may not be applied to the data packet requiring the PDCP replication frequently. Therefore, when activating the PDCP replication, the base station can always include the second type DRB (i.e., the default DRB) in the PDCP replication activation target so that the PDCP replication is applied to the new data packet. If the PDCP replication is required according to the characteristics of the data packet, the base station maps the QoS flow ID of the corresponding data packet to the first type DRB that the PDCP replication is activated and instructs the terminal. If the PDCP replication is not necessary, It is possible to instruct the terminal by mapping the QoS flow ID of the corresponding data packet to the first type DRB whose replication is deactivated.

Example  2

This embodiment relates to a method of always allowing PDCP replication for the second type DRB irrespective of whether or not PDCP replication is enabled for the first type DRB.

That is, even if there is no separate instruction from the base station, or based on an instruction from the base station, the terminal can support PDCP replication by always configuring a split bearer for the second type DRB (i.e., the default DRB). That is, PDCP replication can always be supported for the second type DRB, both when PDCP replication for the first type DRB is activated or when it is deactivated. Also, always activating PDCP replication for the second type DRB may be set independently of whether or not the second type DRB is enabled for PDCP replication.

10 is a diagram for illustrating a further example of a PDCP copy operation according to the present disclosure.

When the UE has the DC or CA structure, the base station always configures the default DRB as a split bearer, even if the UE does not separately instruct the PDCP duplication activation to satisfy the QoS of the data packet requiring high reliability and low delay. PDCP replication can be enabled.

The SDAP layer of the MS transmits to the DRB having a mapping relationship according to the QoS flow ID of the data packet, and the data packet having the QoS flow ID (for example, QoS flow ID 1) that is not mapped to the DRB is transmitted to the DRB . SDAP PDUs transmitted in the default DRB can perform data packet replication by allocating the same SN in the PDCP layer. Therefore, when the UE attempts to transmit a URLLC data packet having a new QoS flow ID, it can satisfy high reliability and low latency through PDCP replication using the default DRB.

The replicated PDCP PDUs are transmitted to different RLC layers. In the RLC layer, RLC-AM mode is applied to divide data packets according to the requested data size in the lower layer, and RLC header can be added to the MAC layer . The MAC layer receiving the RLC PDU can transmit MAC PDUs to different base stations or different carriers through the HARQ function.

The MAC layer of the BS receiving the uplink data packet of the UE transfers the MAC SDU to the RLC layer, and the RLC layer can perform the ARQ function on the data packet not received by applying the RLC-AM mode. Thereafter, the RLC SDU received by the RLC layer can be transmitted to the PDCP layer. In this case, when all the duplicated data packets are successfully transmitted, the PDCP layer of the base station receives replicated PDCP PDUs having the same SN from different RLC layers. The PDCP layer detects duplicated data packets through the SN allocated to the PDCP PDU, stores only one data packet in the buffer, and processes the data packet by transferring the data packets to the upper layer by sorting the data packets in order.

11 is a diagram illustrating a further example of a MAC CE format that directs PDCP replication activation according to the present disclosure.

According to the present embodiment, since the default DRB always activates PDCP replication, when the base station instructs activation of PDCP replication for a specific DRB through a MAC CE message, it is necessary to indicate whether to activate the default DRB in the MAC CE It may be absent. Therefore, the MAC CE indicating whether or not to activate the PDCP copy may set the bit for the default DRB as a spare bit as in the example of FIG. FIG. 11A shows an example in which the bits for the set default DRB are set as spare bits according to the MAC CE configuration of FIG. 9A. FIG. 11B shows an example of the MAC CE configuration when the index of the default DRB is set to 1 according to the MAC CE configuration of FIG. 9B.

Alternatively, it is possible to use a MAC CE format as shown in FIG. 9 (a), but a second type DRB (for example, DRB A, DRB B, DRB C) For example, the default DRB may indicate that PDCP replication is always active. For example, if the bitmap value of MAC CE is 00001xxx (where x is 0 or any value of 1) or if the default DRB is mapped to LSB, the bitmap value of MAC CE is 0000xxx1, where x is 0 Or any value of 1).

Alternatively, the MAC CE format shown in FIG. 9 (b) may be used, (E.g., the default DRB) regardless of whether PDCP replication of the first type DRB (e.g., DRB A, DRB B, DRB C) is enabled or not have. For example, when the index of the default DRB is 1, the bitmap value of MAC CE can be configured in the form of xxxxxx1x (where x is any value of 0 or 1).

Alternatively, the UE can ignore the PDCP duplication activation for the second type DRB (e.g., the default DRB) using the MAC CE format as shown in FIG.

That is, in the example of FIGS. 9 and 11, the MAC CE structure has a difference as to whether to define a bit indicating whether to activate PDCP replication for the default DRB.

For example, in the case where only the default DRB is activated as shown in FIG. 10, the MAC CE format as shown in FIG. 9A has a value of 00001000 or 0000001, and in the MAC CE format like FIG. 9B, When the index of the DRB is 1, it has a value of 00000010. In the MAC CE format as shown in FIG. 11, it can have a value of 00000000.

Alternatively, as for the example in which the default DRB and DRB B are activated as shown in Fig. 8, the MAC CE format as shown in Fig. 9A has a value of 00001010 or 00000101, and in the MAC CE format as shown in Fig. When the index of the default DRB is 1 and the index of DRB B is 4, it has a value of 00010010. The MAC CE format as shown in FIG. 11A may have a value of 00000010 or 00000100. Or a value of 00000010 in the MAC CE format as shown in FIG. 11 (b).

If PDCP replication is always activated for the default DRB as in the present embodiment, PDCP replication can be continuously applied to data packets that do not require PDCP replication. In this case, the base station transmits a QoS flow ID for the corresponding data packet to the DRB (DRB A or DRB C) for which PDCP replication is not activated through a reflective QoS scheme or an RRC connection reconfiguration message, It is possible to prevent unnecessary PDCP replication from being performed.

The BS can not grasp all of the QoS flow IDs of uplink data packets to be transmitted by the MSs (in particular, data packets to be newly transmitted by the MS). On the other hand, when uplink data requesting high QoS is triggered, the terminal must perform uplink transmission so as to satisfy the QoS of the data packet. According to the present embodiment, the UE sets a default bearer structure for the default DRB and performs PDCP replication through the split bearer structure. Therefore, PDCP replication can be supported for uplink transmissions that may require PDCP replication have.

Example  3

The present embodiment is directed to a method for activating PDCP replication when a terminal satisfies a predefined condition.

For example, the UE can autonomously determine whether or not to activate PDCP replication for the second type DRB, based on a predetermined condition, without an instruction from the BS. For the first type DRB, the UE can perform PDCP replication activation or deactivation for the DRB mapped to a specific QoS flow ID according to a BS instruction (for example, MAC CE).

Here, the operation of determining whether to activate PDCP replication of the second type DRB by itself may be performed only when the base station permits it. That is, when the base station allows the UE to determine whether to activate the PDCP replication for the second type DRB by itself (or automatically), if the predetermined condition is satisfied, the UE activates the PDCP replication for the second type DRB , And may disable PDCP replication for the second type DRB when the predetermined condition is not satisfied.

For example, the UE can activate PDCP replication for the second DRB when the uplink channel environment is bad (i.e., less than or equal to a predetermined criterion). The UE may deactivate PDCP replication for the second DRB when the uplink channel environment is good (i.e., above or below a predetermined reference).

Alternatively, the UE can automatically enable or disable PDCP replication according to the QoS flow ID of the data packet. Alternatively, the UE receives and confirms a MAC CE including information for instructing activation of PDCP replication for at least one DRB, and then the UE activates PDCP replication for the second DRB.

Here, the UE can use various methods for determining the uplink channel environment or state. For example, when the number of retransmission requests from the base station in the uplink HARQ operation exceeds a predetermined threshold value, the UE transmits a second DRB that has activated PDCP duplication (i.e., a divided bearer is set) Lt; / RTI &gt; In addition, when the UE acquires information (for example, TA (Timing Advance) value or uplink transmission power control (TPC) value) obtained through the random access procedure exceeds a predetermined threshold value, The data packet to be transmitted can be transmitted through the second DRB that has activated PDCP replication (i.e., the divided bearer is set). In addition, the UE can estimate the uplink channel state based on a CQI (Channel Quality Indicator) value indicating a downlink channel state. If the CQI value is less than a predetermined threshold value, the UE applies PDCP replication to the uplink data packet It is possible.

Here, the decision of the UE to activate PDCP replication may be determined according to the predefined QoS flow ID. The QoS flow ID is predetermined according to the QoS characteristic of the service, and the BS and the UE can know the QoS flow ID in advance. Accordingly, the UE can apply the PDCP replication to the QoS flow ID corresponding to the important service.

Here, the terminal activates PDCP replication after receiving and confirming a MAC CE including information for instructing activation of PDCP replication for at least one DRB. The UE activates PDCP replication for the second DRB regardless of whether the MAC CE is activated or deactivated for the second DRB.

12 is a diagram for explaining a further example of the PDCP copy operation according to the present disclosure.

The base station can indicate whether the UE can perform PDCP replication or not and whether the UE can set up the PDCP replication itself (or automatically) through the RRC message. The base station can instruct activation or deactivation of PDCP replication for a specific DRB of the UE through a MAC CE message.

The base station can determine whether to activate or deactivate PDCP replication based on the uplink channel environment of the UE, the size of the uplink data packet, and the load status of the cell or the carrier. For example, the base station is in a situation where the uplink channel environment of the UE is not good and the cell or the carrier can sufficiently process even if the UE receives the duplicated packet. If the UE determines that the packet size to be transmitted is not small, Can be determined. In this case, the base station grasps the QoS flow ID for the URLLC data packet, identifies the DRB having the mapping relation with the QoS flow ID, configures the MAC CE to activate PDCP replication in the corresponding DRB, Can be transmitted. The MS receiving the MAC CE performs data packet replication in the PDCP layer for the data packet transmitted in the corresponding DRB. In the example of FIG. 12, it is indicated that the specific DRB determined by the base station to activate PDCP replication based on the uplink channel environment or the like is DRB B.

The SDAP layer of the UE transmits a first type DRB having a mapping relationship according to the QoS flow ID of the data packet and the data packet having the QoS flow ID having no mapping relationship with the DRB is a second type DRB (for example, a default DRB ). When the UE wishes to transmit URLLC data having a new QoS flow ID (e.g., QoS flow ID 1) that does not have a mapping relationship between the QoS flow ID and the DRB, the UE transmits the corresponding data packet to the second type DRB , Default DRB). Here, if the base station allows the UE to determine whether to activate the PDCP replication for the second type DRB by itself, the UE can determine whether to activate the PDCP replication for the second type DRB according to whether the predetermined condition is satisfied .

As a concrete example, when the UE determines that the uplink channel environment is not good, the UE can automatically activate PDCP replication.

If the UE desires to transmit a data packet having a new QoS flow ID that requires PDCP replication but PDCP duplication activation is not indicated for the second type DRB (e.g., default DRB) It is possible to determine whether or not to automatically activate PDCP replication for the second type DRB. If the UE determines that the uplink channel environment is not good, the UE performs PDCP replication and determines that the uplink channel environment is good and does not perform PDCP replication.

The uplink channel environment estimation method may be as follows.

The UE can automatically determine whether to activate the PDCP replication by estimating the uplink channel environment through the number of times the UE is requested to retransmit the uplink HARQ in the uplink HARQ.

When the UE transmits an uplink data packet through HARQ, the Node B does not toggle the NDI together with HARQ process ID, UL grant and RV (Redundancy Version) transmission when the UE fails to correctly receive the UL data packet transmitted by the UE To request retransmission. The uplink data retransmission request may occur because the uplink channel environment is not good. Therefore, when the UE repeatedly requests retransmission N times or more from the base station, it transmits information indicating that the retransmission value reaches the N value to the upper layer, and transmits PDCP PDU packet (hereinafter, referred to as &quot; Can be automatically copied and transmitted through different RLC layers. In one example, a threshold value (e.g., an N value) for the number of retransmissions associated with PDCP replication activation may be established via an RRC message at the base station.

As a further example, the terminal may perform PDCP replication automatically based on the indication of the base station for one or more of uplink transmission timing or uplink transmission power. Specifically, the UE can acquire indication information of the BS with respect to at least one of the uplink transmission timing and the uplink transmission power through the random access procedure, estimates the uplink channel environment based on the information, Can be determined automatically.

The random access is used for establishing a connection with a network. When a UE selects a preamble according to a size of an uplink data packet to be transmitted and a downlink path loss and transmits the preamble to a Node B, Response) to the UE. The UE can estimate the uplink channel environment through the TA (Timing Advance) value included in the RAR message and the UL grant.

For example, if the terminal is far from the base station and there are many obstacles around the base station, and the propagation delay is severe, the base station receives the preamble at a shifted timing. Therefore, the base station assigns a TA (Timing Advance) value through the RAR message in order to adjust the transmission / reception timing, and transmits the transmission power that the UE should apply when transmitting the uplink data packet based on the power received from the preamble through the UL grant Can be set. Therefore, the UE can determine that the uplink channel environment is not good if the TA value included in the RAR is large and the data transmission power control (TPC) set value set in the UL grant is large. Therefore, the UE can determine the uplink channel environment based on the information included in the RAR received from the base station (for example, information on the timing or information on the transmission power), and the uplink channel environment is good The PDCP PDU packet to be transmitted thereafter may be automatically copied and transmitted to the different RLC layer. As an example, a threshold for the PDCP replication activation (e.g., a threshold for timing or transmit power) may be established via an RRC message at the base station.

As a further example, the terminal may perform PDCP replication automatically based on the quality of the downlink channel. Specifically, the UE may automatically determine whether to perform PDCP replication for uplink transmission by reporting CQI (Channel Quality Indicator) for the DL channel.

The CQI report is information indicating the downlink channel state. When the base station requests information on the downlink channel environment, the UE transmits a setup value (for example, a fading and coding scheme (MCS) index) to be applied to the downlink transmission based on the measured downlink channel environment information, To the base station.

The UE can estimate the uplink channel environment from the downlink channel environment on which the CQI determination is based. For example, if the downlink channel environment is good, it is estimated that the uplink channel environment is good, and if the downlink channel environment is bad, the uplink channel environment is not good. If the UE determines that the uplink channel environment is not good from the downlink channel environment, it may inform the base station that it will automatically activate PDCP replication by transmitting a CQI report. The base station can implicitly know that the UE has activated the PDCP replication through the reception of the CQI report. In one example, a threshold for the PDCP replication activation (e.g., a threshold for the CQI value) may be established at the base station via an RRC message.

As another concrete example, the UE can activate PDCP replication according to the predefined QoS flow ID. Such as voice call service, streaming video service, Mission Critical Push To Talk (MCPTT) suitable for disaster situations and voice control, V2X (Vehicle-to-Everything) for communicating with road infrastructure and other vehicles during operation The QoS flow IDs defined for critical services requiring low latency and high reliability may be predetermined. In addition, the QoS flow ID may be predetermined for the URLLC service. Specifically, the predefined QoS flow IDs are 1, 2, 3, 4, 5, 6, 7, 8, 9, 65, 66, 69, 70, 75, , 65, 66, 69, and 70 may have higher priority than other QoS flow IDs. The priorities are set in consideration of delay requirements and performance indicators of the service, and Table 1 below shows the defined QoS flow IDs, related services, and priorities. Therefore, when the QoS flow ID having a relatively high priority as described above is transmitted to the second DRB, the UE can automatically activate PDCP replication. At this time, the PDCP replica can be performed only in a data packet that is not a DRB unit but needs a PDCP replica.

QoS flow ID Priority Delay time Packet error probability service One 20 100ms 10 ^-2 Conversational Voice 2 40 150ms 10 ^-3 Conversational Video (Live Streaming) 3 30 50ms 10 ^-3 Real Time Gaming, Vehicle-to-Everything (V2X) messages 4 50 300ms 10 ^-6 Video (buffer streaming) (Non-Conversational Video (Buffered Streaming) 5 10 100ms 10 ^-6 IMS (IP Multimedia Subsystem) signaling 6 60 300ms 10 ^-6 Video (Buffered Streaming) (Video (Buffered Streaming)
TCP based (eg, www, e-mail, chat, ftp, p2p files, sharing, progressive video, etc.) 7 70 100ms 10 ^-3 Voice, video (live streaming), interactive gaming (interactive gaming) 8 80 300ms 10 ^-6 Video (buffer streaming), TCP based (eg www, e-mail, chat, ftp, p2p files, sharing, 9 90 65 7 75ms 10 ^-2 Group calls for public safety net communications (eg, Mission Critical Push To Talk (MCPTT)) 66 20 100ms 10 ^-2 Non-Mission-Critical Push To Talk Voice 69 5 60ms 10 ^-6 Mission-critical delay sensitive signaling for public safety network communications (eg, MCPTT signaling)
Mission Critical Data for Public Safety Net Communications 70 55 200ms 10 ^-6 79 65 50ms 10 ^-2 V2X messages

As another concrete example, when the UE receives a MAC CE including information for activating PDCP replication for at least one DRB, it activates PDCP replication regardless of the activation / deactivation indication for the second DRB to the MAC CE . When the UE receives the MAC CE, the UE determines that it is necessary to perform PDCP replication and activates PDCP replication for the second DRB. At this time, the UE determines to deactivate the PDCP replication for the second DRB when it receives the MAC CE including the information indicating the inactivation of the PDCP replication for the entire DRB from the base station.

If the predetermined condition is satisfied as described above, the UE can perform PDCP replication on the second type DRB (i.e., the default DRB) to which the URLLC data packet having the new QoS flow ID is transmitted. The duplicated data packet is transmitted to different RLC layers. In the RLC layer, RLC-AM mode is applied, and a data packet division and an RLC header are added to the lower layer to meet the requested data size, and the RLC header can be transmitted to the MAC layer. The MAC layer receiving the data packet can transmit data packets to different base stations or different carriers through the HARQ function to the base station.

The MAC layer of the BS receiving the uplink data packet of the MS transmits the data packet to the RLC layer. The RLC layer performs the ARQ function on the data packet which is not received by applying the RLC-AM mode, To the PDCP layer. At this time, if all the duplicated data packets are successfully transmitted, the PDCP layer of the base station receives the duplicated data packets from the different RLC layers. The PDCP layer detects duplicate data packets, stores only one data packet in the buffer, and processes the data packets by arranging the data packets in order and transferring them to an upper layer.

As described above, the UE can guarantee reliable transmission of data by determining whether to activate the PDCP replica by itself. Also, by determining whether to activate PDCP replication through the uplink channel environment estimation, PDCP replication can be efficiently activated only when PDCP replication is required. If the data packet transmitted by activating the PDCP automatically by the UE is a data packet that does not require PDCP replication because the BS determines that the data packet is transmitted, the BS transmits a corresponding data packet through a reflective QoS scheme or an RRC connection reconfiguration message. It is possible to prevent unnecessary PDCP duplication from being performed by mapping the QoS flow ID to the DRB (for example, DRB A or DRB C) in which PDCP replication is not activated.

In addition, the terminal may automatically disable PDCP replication. For example, if the predetermined condition for the uplink channel environment is not satisfied, the UE can deactivate PDCP replication. Also, even if the terminal satisfies the predetermined condition for the uplink channel environment, the terminal may deactivate the PDCP replication when the buffer occupancy rate of the terminal is high.

In addition, when determining whether to activate the PDCP replication by itself (or automatically), if there is an instruction to explicitly activate the PDCP replication from the base station, the PDCP replica Can be activated or deactivated. For example, the UE determines to activate PDCP replication for the second type DRB to determine itself, but it is instructed to explicitly disable PDCP replication for the second type DRB in the MAC CE provided by the base station to the UE In this case, the terminal may disable PDCP replication for the second type DRB. Or if the MS decides to deactivate PDCP replication for the second type DRB to determine itself, but if the base station is instructed to explicitly enable PDCP replication for the second type DRB in the MAC CE it provides to the terminal, The terminal can activate PDCP replication for the second type DRB.

13 is a flowchart for explaining the PDCP copy activation operation according to the present disclosure.

In step S1310, the base station can transmit information indicating whether to activate the PDCP replication to the terminal. The PDCP duplication enable / disable indication information may include information indicating whether to activate PDCP replication for one or more of the first type DRB or the second type DRB.

For example, the PDCP duplication enable / disable indication information may include information indicating whether PDCP duplication is enabled for each of one or more first type DRBs and whether PDCP duplication for the second type DRB is enabled (e.g., MAC CE type information). Here, when activation of PDCP replication for one of the first type DRBs is indicated, PDCP copy activation can always be instructed for the second type DRN (see Embodiment 1).

As a further example, the PDCP duplication enable / disable indication information may include information (e.g., information in the form of a MAC CE in FIG. 11) indicating whether or not to activate PDCP replication for each of one or more first type DRBs, For the 2-type DRB, PDCP copy activation can always be instructed without any additional instruction. Alternatively, the PDCP duplication enable / disable indication information may include information indicating whether to activate the PDCP duplication for each of the one or more first type DRBs and whether to activate the PDCP duplication for the second type DRB (e.g., Information), and regardless of whether PDCP replication of the first type DRB is activated, PDCP replication activation may always be indicated for the second type DRB (see Embodiment 2).

As a further example, the PDCP duplication enable / disable indication information may include information indicating whether the UE permits itself (or automatically) to determine whether to activate PDCP replication for the second type DRB. Additionally, it may include information (e.g., information in the form of a MAC CE in FIG. 9) indicating whether to activate PDCP replication for each of the one or more first type DRBs and whether to activate PDCP replication for the second type DRB In addition, even if the UE itself is allowed to decide whether to activate the PDCP replication, the PDCP replication activation may be applied according to the explicit indication of the base station instead of the determination of the UE according to the explicit indication of the base station (see Embodiment 3).

Step S1315 may be performed when the base station allows the mobile station to determine whether to activate PDCP replication for the second type DRB. If the UE itself is allowed to determine whether to activate the PDCP, the UE can determine whether to activate the PDCP replication for the second type DRB according to whether the predetermined condition is satisfied. For example, the predetermined condition may be determined based on an uplink channel state or a predefined QoS flow ID or MAC CE reception. More specifically, the predetermined condition may include an HARQ retransmission request count for uplink transmission, an uplink transmission timing (obtained through a random access procedure) or an uplink transmission power, a downlink channel quality (e.g., E.g., CQI, for example, the CQI, to determine whether to activate PDCP replication for the second type DRB. Alternatively, the terminal may determine whether to enable PDCP replication for a predefined QoS flow ID for critical data. Alternatively, when receiving a MAC CE including information on which PDCP replication is enabled for at least one DRB, it may automatically decide to activate PDCP replication.

In step S1320, if the PDCP duplication enable / disable indication information received from the base station indicates activation of PDCP duplication for the second type DRB, or if the UE itself determines to activate the PDCP duplication, Can be performed. For example, a new uplink data packet may correspond to a data packet to be transmitted through a second type DRB (e.g., a default DRB) in which the DRB to which the QoS flow ID of the corresponding data packet is mapped is not determined have. If PDCP replication for the second type DRB is indicated as being inactive or the UE itself determines, the UE may transmit a new uplink data packet through the second DRB without PDCP replication.

In step S1330, the UE can transmit a data packet mapped to each DRB to the base station through one or more of the first type DRB or the second type DRB to the base station. Here, depending on whether PDCP replication is enabled for each DRB, PDCP replication may or may not be applied to a data packet transmitted through the corresponding DRB.

In step S13440, the base station can process the data packet received from the terminal. If a plurality of (e.g., two) data packets in the received data packet have the same PDCP SN value (i.e., PDCP replicated data packets), one of them is stored in the buffer, and the other Can be discarded.

14 is a diagram showing a configuration of a base station apparatus and a terminal apparatus according to the present disclosure.

The base station apparatus 1400 may include a processor 1410, an antenna unit 1420, a transceiver 1430, and a memory 1440.

The processor 1410 performs baseband related signal processing and may include an upper layer processing unit 1411 and a physical layer processing unit 1415. [ The upper layer processing unit 1411 can process an operation of a MAC (Medium Access Control) layer, an RRC (Radio Resource Control) layer, or higher layers. The physical layer processing unit 1415 can process the operation of the physical (PHY) layer (e.g., uplink received signal processing, downlink transmission signal processing). In addition to performing baseband-related signal processing, the processor 1410 may also control operation of the overall base station apparatus 1400.

The antenna unit 1420 may include one or more physical antennas, and may support Multiple Input Multiple Output (MIMO) transmission and reception when the antenna includes a plurality of antennas. The transceiver 1430 may include a radio frequency (RF) transmitter and an RF receiver. The memory 1440 may store computationally processed information of the processor 1410, software associated with the operation of the base station device 1400, an operating system, applications, and the like, and may include components such as buffers.

The processor 1410 of the base station device 1400 may be configured to implement base station operation in the embodiments described herein.

For example, the upper layer processing unit 1411 of the processor 1410 of the base station apparatus 1400 may include a PDCP copy activation determination unit 1412 and a data packet processing unit 1413.

The PDCP duplication activation determination unit 1412 can generate information indicating whether to activate or deactivate PDCP for at least one of the at least one first type DRB or the second type DRB set for the terminal device 1450. [

For example, the PDCP duplication activation determination unit 1412 determines whether to activate the PDCP replication for each of the one or more first type DRBs and whether to activate the PDCP replication for the second type DRB (e.g., 9 information of the MAC CE format). Here, when activation of PDCP replication for one of the first type DRBs is indicated, PDCP copy activation can always be instructed for the second type DRN (see Embodiment 1).

As a further example, the PDCP duplication activation determination unit 1412 may include information (e.g., information in the form of a MAC CE in FIG. 11) indicating whether or not to activate PDCP replication for each of the one or more first type DRBs PDCP replication activation indication information can be generated. In this case, PDCP copy activation can always be instructed to the second type DRB without any other instruction. Alternatively, the PDCP duplication enable / disable determination unit 1412 determines whether the PDCP duplication enable / disable indication information includes information indicating whether to activate PDCP replication for each of the one or more first type DRBs and whether to activate PDCP replication for the second type DRBs For example, information in the form of a MAC CE shown in Fig. 9). In this case, irrespective of whether or not the PDCP replication of the first type DRB is activated, the PDCP replication activation may be always instructed for the second type DRB (see Embodiment 2).

As a further example, the PDCP duplication activation determination unit 1412 may include information indicating whether the terminal apparatus 1450 allows itself (or automatically) to determine whether to activate PDCP replication for the second type DRB PDCP replication activation indication information can be generated. In addition, the PDCP duplication enable / disable indication information generated by the PDCP duplication enable / disable determination unit 1412 may include whether to activate PDCP replication for each of the one or more first type DRBs, and whether to activate PDCP replication for the second type DRBs (For example, information in the form of a MAC CE shown in Fig. 9). In this case, even if the terminal device 1450 is allowed to decide whether to activate the PDCP replication itself, the PDCP replication activation state may be applied according to the explicit indication of the base station 1450 instead of the determination of the terminal device 1450 in accordance with the explicit indication of the base station (See Example 3).

The data packet processing unit 1413 can receive and process the data packet received from the terminal device 1450 through the physical layer processing unit 1415. For example, when a plurality of data packets (i.e., PDCP replicated data packets) having the same PDCP SN value are detected, the data packet processing unit 1413 stores one of them in a buffer, (discard).

The terminal apparatus 1450 may include a processor 1460, an antenna unit 1470, a transceiver 1480, and a memory 1490.

The processor 1460 performs baseband-related signal processing, and may include an upper layer processing unit 1461 and a physical layer processing unit 1465. The upper layer processing unit 1461 can process the operations of the MAC layer, the RRC layer, or higher layers. The physical layer processing unit 1465 can process the operation of the PHY layer (e.g., downlink received signal processing, uplink transmission signal processing). In addition to performing baseband-related signal processing, the processor 1460 may also control operation of the entire terminal device 1450.

The antenna unit 1470 may include one or more physical antennas, and may support MIMO transmission / reception when the antenna includes a plurality of antennas. The transceiver 1480 may include an RF transmitter and an RF receiver. The memory 1490 may store information processed by the processor 1460, software related to the operation of the terminal device 1450, an operating system, applications, and the like, and may include components such as buffers.

The processor 1460 of the terminal device 1450 can be configured to implement the operation of the terminal in the embodiments described in the present invention.

The upper layer processing unit 1461 of the processor 1460 of the terminal device 1450 may include a PDCP duplication activation determination unit 1462 and a PDCP duplication performing unit 1463.

The PDCP duplication activation determination unit 1462 can determine whether or not to activate the PDCP duplication itself based on an instruction from the base station.

For example, the PDCP duplication activation indication information received from the base station apparatus 1400 may include information indicating whether to activate PDCP replication for each of one or more first type DRBs and whether to activate PDCP replication for the second type DRBs 9), the PDCP duplication activation determination unit 1462 determines whether to activate the PDCP duplication as instructed by the base station apparatus 1400 for each DRB . Here, when the PDCP replication for one of the first type DRBs is instructed to be activated, the PDCP copy activation may be always instructed for the second type DRB. Alternatively, PDCP copy activation may always be instructed for the second type DRB, regardless of whether PDCP replication for the first type DRB is enabled or not.

As a further example, the PDCP duplication enable / disable indication information received from the base station apparatus 1400 may include information indicating whether or not to activate PDCP replication for each of the one or more first type DRBs (e.g., Information), the PDCP duplication activation determination unit 1462 can determine whether to activate the PDCP duplication as instructed by the base station apparatus 1400 for each of the first type DRBs. In this case, the PDCP duplication activation determination unit 1462 can determine that PDCP duplication activation is always instructed for the second type DRB.

As a further example, the PDCP duplication activation enable / disable information received from the base station apparatus 1400 includes information indicating whether the mobile station itself (or automatically) determines whether to activate PDCP replication for the second type DRB The PDCP duplication enable / disable determination unit 1462 may determine whether to activate PDCP replication for the second type DRB based on whether or not the predetermined condition is satisfied. For example, the predetermined condition may be determined based on an uplink channel state. More specifically, the predetermined condition may include an HARQ retransmission request count for uplink transmission, an uplink transmission timing (obtained through a random access procedure) or an uplink transmission power, a downlink channel quality (e.g., E.g., CQI, for example, the CQI, to determine whether to activate PDCP replication for the second type DRB. Or a specific QoS flow ID that is predefined for the critical service. The UE can determine whether to activate PDCP replication for the QoS flow ID transmitted in the second type DRB.

The PDCP duplication performing unit 1453 performs a PDCP duplication check on the data packet transmitted through each of one or more of the first type DRB or the second type DRB determined to perform the PDCP replication by the PDCP duplication activation determination unit 1462, It is possible to generate a redundant data packet including the same PDCP SN. Alternatively, for a data packet transmitted through the DRB with PDCP replication disabled, the data packet can be transmitted to the physical layer processing unit 1465 without generating a duplicate data packet. For example, the uplink data packet to be newly transmitted may be transmitted through the second type DRB when the QoS flow ID and the DRB mapping relation are not defined. Depending on whether or not the PDCP replication for the second type DRB is activated, It may or may not apply PDCP replication for the link data packet.

The physical layer processing unit 1465 can map the data packet to which the PDCP replication is applied or the data packet to which the PDCP replication is not applied, received from the upper layer processing unit 1460, to the physical resource and transmits the data packet to the base station apparatus 1400.

In the operation of the base station apparatus 1400 and the terminal apparatus 1450, the same elements as those of the exemplary embodiments of the present invention can be applied, and redundant description will be omitted.

Although the exemplary methods of this disclosure are represented by a series of acts for clarity of explanation, they are not intended to limit the order in which the steps are performed, and if necessary, each step may be performed simultaneously or in a different order. In order to implement the method according to the present disclosure, the illustrative steps may additionally include other steps, include the remaining steps except for some steps, or may include additional steps other than some steps.

The various embodiments of the disclosure are not intended to be all-inclusive and are intended to illustrate representative aspects of the disclosure, and the features described in the various embodiments may be applied independently or in a combination of two or more.

In addition, various embodiments of the present disclosure may be implemented by hardware, firmware, software, or a combination thereof. In the case of hardware implementation, one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays A general processor, a controller, a microcontroller, a microprocessor, and the like.

The scope of the present disclosure is to be accorded the broadest interpretation as understanding of the principles of the invention, as well as software or machine-executable instructions (e.g., operating system, applications, firmware, Instructions, and the like are stored and are non-transitory computer-readable medium executable on the device or computer.

Claims (1)

A method for performing a PDCP (Packet Data Convergence Protocol) replication in a wireless communication system,
Receiving from a base station a PDCP duplication activation indication information for at least one of a first type DRB (Data Radio Bearer) or a second type DRB;
Performing PDCP replication for a new uplink data packet when PDCP replication for the second type DRB is activated; And
Transmitting a data packet mapped to each DRB through one or more of the one or more first type DRBs or the second type DRBs.

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