KR20210009176A - Method and Apparatus of DRB Path Switching in Dual Connectivity and Sidelink Radio Bearer Release - Google Patents

Abstract

The present invention relates to a communication technique and a system for combining a 5G communication system for supporting a higher data transmission rate after a 4G system with IoT technology. A control signal processing method in a wireless communication system comprises: a step of receiving a first control signal transmitted from a base station; a step of processing the received first control signal; and a step of transmitting a second control signal generated based on the processing to the base station. The present invention can be applied to intelligent services (e.g., smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail, security and safety-related services, etc.) based on 5G communication technology and IoT-related technology.

Description

DRB Path Switching in Dual Connectivity and Sidelink Radio Bearer Release {Method and Apparatus of DRB Path Switching in Dual Connectivity and Sidelink Radio Bearer Release}

The present disclosure (disclosure) relates to a wireless communication system, and to a method and apparatus for supporting seamless communication in the case of a radio link failure of a cell group in a wireless communication system.

In addition, the present disclosure relates to a deactivation determination and release operation of a sidelink radio bearer.

Efforts have been made to develop an improved 5G (5th generation) communication system or a pre-5G communication system in order to meet the increasing demand for wireless data traffic after the commercialization of 4G (4th generation) communication systems. For this reason, the 5G communication system or the pre-5G communication system is called a communication system after a 4G network (Beyond 4G Network) or a system after an LTE system (Post LTE). In order to achieve a high data rate, the 5G communication system is being considered for implementation in the ultra high frequency (mmWave) band (eg, 60 gigabyte (70 GHz) band). In order to mitigate the path loss of radio waves in the ultra-high frequency band and increase the transmission distance of radio waves, in 5G communication systems, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed. In addition, in order to improve the network of the system, in 5G communication system, advanced small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation And other technologies are being developed. In addition, in the 5G system, advanced coding modulation (ACM) methods such as Hybrid FSK and QAM Modulation (FQAM) and SWSC (Sliding Window Superposition Coding), advanced access technologies such as Filter Bank Multi Carrier (FBMC), NOMA (non-orthogonal multiple access), and sparse code multiple access (SCMA) have been developed.

On the other hand, the Internet is evolving from a human-centered network in which humans generate and consume information, to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required, and recently, a sensor network for connection between objects, machine to machine , M2M), and MTC (Machine Type Communication) technologies are being studied. In the IoT environment, intelligent IT (Internet Technology) services that create new value in human life by collecting and analyzing data generated from connected objects can be provided. IoT is the field of smart home, smart building, smart city, smart car or connected car, smart grid, healthcare, smart home appliance, advanced medical service, etc. through the convergence and combination of existing IT (information technology) technology and various industries. Can be applied to.

Accordingly, various attempts have been made to apply a 5G communication system to an IoT network. For example, technologies such as sensor network, machine to machine (M2M), and machine type communication (MTC) are implemented by techniques such as beamforming, MIMO, and array antenna, which are 5G communication technologies. . The application of a cloud radio access network (cloud RAN) as the big data processing technology described above can be said as an example of the convergence of 3eG technology and IoT technology.

An object of the present disclosure is to provide a method and apparatus for supporting seamless communication when a radio link failure of a cell group occurs.

In addition, an object of the present disclosure is to provide a deactivation determination and release operation of a sidelink radio bearer.

The present invention for solving the above problem is a control signal processing method in a wireless communication system, the method comprising: receiving a first control signal transmitted from a base station; Processing the received first control signal; And transmitting a second control signal generated based on the processing to the base station.

According to an embodiment of the present invention, even when a radio link failure occurs in a cell group, seamless communication can be supported.

In addition, according to an embodiment of the present invention, efficient communication is possible through an operation of determining and releasing deactivation of a radio bearer.

1A is a diagram showing a dual connection structure between a base station and a terminal in a wireless communication system.
1B is a diagram illustrating a structure of an SRB of a base station and a method for a terminal to notify a base station of an MCG failure when an MCG fails.
1C is a diagram illustrating an SRB structure of a base station and a method for a UE notifying a base station of an SCG failure when an SCG fails.
1D is a diagram illustrating a phenomenon in which transmission of data through an MCG link is delayed due to an MCG failure.
1E is a diagram illustrating a phenomenon in which transmission of data through an SCG link is delayed due to an SCG failure.
1F is a diagram illustrating a method of preventing a transmission delay due to an MCG failure.
1G is a diagram illustrating a method of preventing transmission delay due to SCG failure.
1H is a diagram illustrating a method of preventing a transmission delay due to an MCG failure.
1I is a diagram illustrating a method of preventing transmission delay due to SCG failure.
1j is a diagram illustrating a procedure of setting RRC between a base station and a terminal.
1K is a diagram illustrating a method of preventing transmission delay due to MCG failure.
1L is a diagram illustrating a method of preventing transmission delay due to SCG failure.
1M is a diagram showing the structure of a base station according to an embodiment of the present invention.
1N is a diagram showing the structure of a terminal according to an embodiment of the present invention.
2A is a diagram illustrating a scenario of performing inter-terminal communication in V2X (Vehicular to Everything) communication.
2B is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2C is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2D is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2E is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2F is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2G is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2H is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2I is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2j is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2K is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2L is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2M is a diagram illustrating an operation of setting and releasing a sidelink radio bearer for V2X communication.
2N is a diagram illustrating an operation of transmitting V2X communication information to a base station and receiving reconfiguration by the base station.
2O is a diagram illustrating an operation method of determining a deactivation state of a sidelink radio bearer by a timer.
2P is a diagram illustrating an operation method of determining a deactivation state of a sidelink radio bearer by a timer.
2q is a diagram illustrating an operation of releasing a sidelink connection between two terminals.
2R is a diagram showing the structure of a base station according to an embodiment of the present invention.
2S is a diagram showing the structure of a terminal according to an embodiment of the present invention.

In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1A shows a structure of dual connectivity between a base station and a terminal in a wireless communication system.

In the dual connectivity structure, the base station has two base station nodes 1a-01 and 1a-02, and the nodes may be connected via an X2 interface or an Xn interface (1a-03). Among them, the node that is mainly connected to the terminal is called a master node (MN) (1a-01), and the node that is connected secondary for a dual connection structure is called a secondary node (secondary note, SN) (1a-02). do. Among them, the master node is SRB1 (signaling radio bearer 1) that can indicate the configuration of the terminal's radio resource control (RRC) and SRB2 that can transmit a non-access stratum (NAS) message that establishes a connection between the terminal and the core network. It can be an anchor point of (signaling radio bearer). Each node is connected to the terminal by one or more cells to perform communication.The cell is a PCell (primary cell) (1a-04) that is essentially connected to a master node, and a PSCell that is essentially connected to a secondary node. It can be divided into (primary secondary cell) (1a-05), and SCell (secondary cell) (1a-06, 1a-07, 1a-08, 1a-09) that each node has secondary. Among them, the cells managed by the master node are collectively referred to as master cell group (MCG) (1a-10), and the cells managed by the secondary node are collectively referred to as secondary cell group (SCG) (1a-11). ).

Terminal 1a-30 also transmits data and control information to the base station through PCell (1a-14), PSCell (1a-15) and additional SCells (1a-16, 1a-17, 1a-18, 1a-19). I can. In this case, the PCell, PSCell, and each SCell are not physically different from those of the base station, but may be referred to as resources of the same frequency band corresponding to each other. Therefore, it is possible to have a master cell group (1a-20) and a secondary cell group (1a-21), and this configuration is set equal to each other during the connection process between the base station and the terminal.

In this dual connectivity structure, when the radio link condition of the secondary cell group (1a-21) is poor, and a radio link failure of the secondary cell group, that is, SCG RLF, occurs, the master cell group (1a-20) It transmits an SCG Failure Information message to the master node. The corresponding SCG failure information message may be transmitted to SRB1, and the base station receiving the message may instruct a configuration or release operation of the secondary cell group in which the SCG RLF has occurred.

At this time, data transmitted to the master cell group can be continuously transmitted without interruption. This is because SCG RLF is purely a problem of the secondary cell group and may not interfere with transmission performed to the master cell group. . In addition, an SCG failure information message may be transmitted even when the SCG fails to reset. In general, SCG RLF and reset failure may be collectively referred to as SCG failure.

On the other hand, if the radio link condition of the master cell group (1a-20) is poor and the radio link failure of the master cell group, that is, MCG RLF occurs, the radio link condition of the master cell group is not good. Can't deliver Therefore, in this case, it may be necessary to perform an RRC connection reestablishment procedure to reconfigure the master cell group. In the RRC connection re-establishment procedure, since the corresponding operation is performed only in the radio link condition of the master cell group regardless of the connection state of the secondary cell group, interruption occurs in which data transmitted to the secondary cell group is also stopped. However, when the secondary cell group 1a-21 is available, it may not necessarily be necessary to stop data transmission of the secondary cell group.

Therefore, if the MCG RLF report can be made to the secondary cell group, disconnection due to re-establishment of the RRC connection can be prevented and data transmission of the secondary cell group can be prevented. In addition, it is possible to perform an RRC connection re-establishment operation even when a handover or RRC reconfiguration with sync fails, and a similar method to the MCG RLF report can be used. In general, these can be collectively referred to as MCG failure.

1B shows a structure of an SRB of a base station and a method in which a UE informs a base station of an MCG failure when an MCG fails.

The signaling radio bearer (SRB) is a radio bearer for radio resource control (RRC) configuration of the base station, and the base station instructs procedures such as RRC configuration, reconfiguration, and re-establishment through the SRB.

In addition, the terminal may transmit a response message to a configuration, reconfiguration, and re-establishment message of the base station through the SRB, and may transmit a message that the terminal should trigger. For example, an SCG failure information message transmitted when an SCG failure occurs can be transmitted using an SRB.

SRB may be divided into SRB1, SRB2, SRB3, etc. and set according to use. SRB1 and SRB2 (1b-10) may be configured between the master node (1b-01) and the terminal, and SRB3 (1b-20) may be configured between the secondary node (1b-02) and the terminal.

SRB1 (1b-10) is mainly used for transmission of messages for direct connection between a terminal and a base station. SRB2 (1b-10) is mainly used for transmission of a non-access stratum (NAS) message between the core network and the terminal. SRB3 (1b-20) is used for transmission of messages for direct connection between the secondary node and the terminal.

At this time, SRB1 and SRB2 may have RRC and PDCP located in the master node (1b-11), and radio link control (RLC) and medium access control (MAC) may exist in the master node and the secondary node, respectively (1b-12, 1b. -13).

At this time, if the RLC is located only in the MCG, it is referred to as non-split SRB (SRB), and if the RLC is located in the MCG and SCG, it is referred to as split SRB (split SRB). That is, in case of SRB1, it may be referred to as split SRB1. On the other hand, in SRB3, RRC and PDCP are located in the secondary node (1b-21), and RLC and MAC are located in the secondary node (1b-22).

In the embodiment of FIG. 1B, only a part of the SRB is described, but when the terminal and the base station are connected, a data radio bearer (DRB) to which data is to be transmitted may be set.

When the terminal (1b-00) detects an MCG failure due to an MCG RLF or a reset failure accompanied by synchronization (1b-30), the base station informs the base station that the MCG failure has occurred because transmission using the MCG is no longer possible. Need to be informed. At this time, if the SCG link is available, the UE can transmit the message using the SCG (1b-40). At this time, if SRB1 is set, the split SRB1 (1b-10) can be used, and if SRB3 is set, the MCG failure information can be transmitted to the secondary node 1b-20 through SRB3. However, since the anchor node of SRB3 becomes the secondary node 1b-20, the corresponding information needs to be transmitted again to the master node 1b-10 in charge of MCG connection. Accordingly, the contents of the failure report message 1b-40 transmitted to SRB3 may be forwarded as it is.

However, in another embodiment, a certain terminal may use a different message to reprocess and transmit that the MCG failure has occurred and for some reason. Thereafter, the base station or the master node among the base stations may instruct a handover to change the MCG of the terminal and reconfiguration accompanied by synchronization in order to solve the MCG failure. In another embodiment, it is possible to instruct a role swap or the like in which the roles of the master node 1b-01 and the secondary node 1b-02 are swapped.

At this time, the MCG failure information message may include the following information.

- In which cell group the failure occurred (MCG failure or SCG failure)

- What type of failure occurred (RLF, reset failure with synchronization, etc.)

- Measurement report set by the master node

- Report of measurements set by the secondary node

If the secondary cell group is operated by a different radio access technology (RAT), the measurement report set by the secondary node may be encoded by coding used in the RAT of the secondary cell group.

When an MCG failure occurs, data of a radio bearer (DRB) for data being transmitted using an MCG RLC may not be transmitted well due to a bad link condition of the MCG. This is hundreds of milliseconds (ms) until the UE reports the MCG failure (1b-40), and the base station or the master node of the base stations instructs a handover to change the MCG of the UE, reconfiguration accompanied by synchronization in order to resolve the MCG failure. ) To a few seconds. If data is not transmitted well during this time, the quality of user service may deteriorate.

1C shows a structure of an SRB of a base station and a method in which a UE informs the base station of an SCG failure when an SCG fails.

The SRB is a radio bearer for RRC configuration of the base station, and through the SRB, the base station instructs procedures such as RRC configuration, reconfiguration, and re-establishment.

In addition, a response message to a configuration, reconfiguration, and re-establishment message of a base station may be transmitted through the terminal dms SRB, and a message to be triggered by the terminal may be transmitted. For example, an SCG failure information message transmitted when an SCG failure occurs can be transmitted using an SRB.

SRB may be divided into SRB1, SRB2, SRB3, etc. and set according to use. SRB1 and SRB2 (1c-10) may be configured between the master node (1c-01) and the terminal, and SRB3 (1c-20) may be configured between the secondary node (1c-02) and the terminal.

SRB1 (1c-10) is mainly used for transmission of messages for direct connection between a terminal and a base station. SRB2 (1c-10) is mainly used for transmission of NAS messages between the core network and the terminal. SRB3 (1c-20) is used for transmission of messages for direct connection between the secondary node and the terminal.

At this time, SRB1 and SRB2 may have RRC and PDCP in the master node (1c-11), and RLC and MAC in the master node and secondary node, respectively (1c-12, 1c-13).

At this time, if the RLC is located only in the MCG, it is called a split SRB, and if the RLC is located in the MCG and SCG, it is called a split SRB. That is, in case of SRB1, it may be referred to as split SRB1. On the other hand, in SRB3, RRC and PDCP are located in the secondary node (1c-21), and RLC and MAC are located in the secondary node (1c-22).

In the embodiment of FIG. 1C, only a part of the SRB is described, but when the terminal and the base station are connected, a DRB to which data is to be transmitted may also be set.

When the terminal (1c-00) detects SCG failure due to SCG RLF or reconfiguration failure accompanied by synchronization (1c-30), the base station sends information that SCG failure has occurred because transmission using SCG is no longer possible. Need to be informed. At this time, if the MCG link is available, the message can be transmitted using the MCG. (1c-40) At this time, if SRB1 is set, the corresponding SCG failure information can be delivered using SRB1 (1c-10). Thereafter, the base station or the master node among the base stations may instruct SCG reconfiguration to change the SCG of the terminal in order to solve the SCG failure.

At this time, the SCG failure information message may include the following information.

-In which cell group the failure occurred (MCG failure or SCG failure)

-What type of failure occurred (RLF, reset failure with synchronization, etc.)

-Measurement report set by the master node

-Measurement report set by the secondary node

If the secondary cell group is operated by a different RAT, the measurement report set by the secondary node may be encoded with a coding used in the RAT of the secondary cell group.

When SCG failure occurs, data of a radio bearer (DRB) for data being transmitted using SCG RLC may not be transmitted well due to a bad link condition of the SCG. This is the time from hundreds of milliseconds (ms) to several seconds for the UE to report SCG failure (1c-40) and instruct the base station or the master node of the base station to reconfigure the SCG of the UE to resolve the SCG failure. Because it can take. If data is not transmitted well during this time, the quality of user service may deteriorate.

1D shows a phenomenon in which data transmission through an MCG link is delayed due to an MCG failure. When normal transmission/reception is difficult due to poor MCG connection between the terminal and the base station, an OOS (Out-of-sync) situation may occur (1d-10).

The OOS may be defined to recognize that OOS has occurred when the terminal satisfies a specific condition by defining a condition of OOS in an actual communication protocol, and to perform an operation after the OOS. In some embodiments, a hypothetical decoding failure probability of a physical downlink control channel (PDCCH) may be defined as OOS when a predetermined value or more.

When OOS occurs, normal transmission and reception of DRB data transmitted to a cell or cell group in which OOS has occurred is difficult. If the cell group in which the corresponding OOS has occurred is the MCG, and the OOS continues for a predetermined time set in advance, the MCG RLF can be declared (1d-20). When the MCG RLF is declared, an RRC re-establishment request procedure or an MCG failure report procedure may be performed (1d-30).

If the base station is notified that the MCG RLF has occurred and the base station instructs the base station to perform handover or re-establishment of the RRC, the recovery of the MCG link is completed and normal transmission/reception is possible (1d-40). At this time, it is difficult to transmit and receive DRB data through MCG normally from time t0 (1d-10) when the OOS occurs to time t3 (1d-40), which is the recovery time of the MCG link due to reconfiguration of the base station. It becomes a situation (1d-60). This stops data transmission. The length of this time may take from several hundred milliseconds (ms) to several seconds, and this may lead to a decrease in the quality of user service such as a decrease in TCP throughput.

1E shows a phenomenon in which transmission of data through an SCG link is delayed due to an SCG failure. If normal transmission/reception is difficult because the SCG connection between the terminal and the base station is not good, an OOS situation may occur (1e-10).

The OOS may be defined to recognize that OOS has occurred when the terminal satisfies a specific condition by defining a condition of OOS in an actual communication protocol, and to perform an operation after the OOS. In some embodiments, when the virtual decoding failure probability of the PDCCH is greater than or equal to a predetermined value, it may be defined as OOS.

When OOS occurs, normal transmission and reception of DRB data transmitted to a cell or cell group in which OOS has occurred is difficult. If the cell group in which the corresponding OOS has occurred is the SCG, and the OOS continues for a predetermined time set in advance, the SCG RLF can be declared (1e-20). When the SCG RLF is declared, the SCG failure reporting procedure can be performed (1e-30).

If the base station is notified that the SCG RLF has occurred and the base station instructs the RRC reconfiguration afterwards, the recovery of the SCG link is completed and normal transmission/reception is possible (1e-40). At this time, it is difficult to transmit and receive DRB data through SCG normally from time t0 (1e-10) when the OOS occurs to time t3 (1e-40), which is the recovery time of the SCG link due to reconfiguration of the base station. It becomes a situation. (1e-60) This stops data transmission. The length of this time may take from several hundred milliseconds (ms) to several seconds, and this may lead to a decrease in the quality of user service such as a decrease in TCP throughput.

1F shows a method for preventing transmission delay due to MCG failure proposed in the present invention.

As described in FIG. 1D, if data transmission to the MCG link is not normally performed after the MCG failure, this may lead to deterioration of the quality of user service. In order to prevent this problem, when the MCG link is not good, it is necessary to continuously perform data transmission using the SCG link.

To this end, when OOS (Out-of-sync) of the MCG link occurs (1f-10), the UE may perform data transmission to the SCG for the configured split DRB (1f-20). Specifically, data can be transmitted to the SCG for a split DRB set by one of the following methods.

-The split DRB's primary radio link control (RLC) bearer is set to SCG RLC. The primary RLC bearer refers to an RLC bearer used for transmission when the amount of data to be transmitted by the split DRB is less than a preset threshold (ul-dataSplitThreshold). For this reason, the UE preferentially uses the SCG RLC bearer for transmission.

-Change the split DRB's ul-dataSplitThreshold to 0 or a preset finite value. Accordingly, it is possible to quickly start using the secondary RLC bearer, and if the SCG RLC bearer is a secondary RLC bearer, it can be quickly transmitted to the SCG RLC bearer by a small ul-dataSplitThreshold value.

-Enable packet duplication for split DRB. Accordingly, the PDCP layer duplicates a packet to be transmitted and transmits the same duplicate packet to the primary RLC and the secondary RLC, respectively, thereby enabling transmission to the SCG RLC bearer.

-For split DRB, the PDCP layer sends a packet to the SCG RLC regardless of the existing settings. For this reason, it is possible to enable transmission to the SCG RLC regardless of the setting of the split DRB.

When the terminal performs data transmission to the SCG for the split DRB by one of the above methods, the configuration may be maintained only in OOS or MCG RLF situations in which the MCG link cannot perform normal transmission/reception. That is, data transmission to the SCG may be enabled until the regression condition for returning to the existing setting is satisfied.

The session condition for returning to the existing setting may be a condition set in advance. For example, a case in which the UE returns to a state in which normal transmission/reception is possible by satisfying an IS (In-sync) condition, or an MCG link is restored by receiving an RRC reconfiguration message from a base station may be an existing set regression condition.

Here, the IS can be defined to recognize that the IS has occurred when the terminal satisfies a specific condition by defining a condition of the IS in an actual communication protocol and to perform an operation after the IS. In some embodiments, when the virtual decoding failure probability of the PDCCH is less than a certain value, it may be defined as IS. When IS occurs, it may be assumed that normal transmission/reception of DRB data transmitted to the cell or cell group in which the IS occurs can be performed.

The terminal checks whether the existing configuration regression condition is satisfied (1f-30), and if it satisfies the existing configuration regression condition, it can return to the existing configuration and perform transmission (1f-40).

Otherwise, if the existing set regression condition is not satisfied, the split DRB SCG transmission can be performed as set in step (1f-20).

Meanwhile, although the present disclosure has described the operation of the terminal as an example, the above method may also be applied to a base station.

1G shows a method for preventing transmission delay due to SCG failure proposed in the present invention.

As described in FIG. 1E, if data transmission to the SCG link is not normally performed after the SCG failure, this may lead to deterioration of the quality of user service. In order to prevent this problem, when the SCG link is not good, it is necessary to continue data transmission using the MCG link.

To this end, when OOS (Out-of-sync) of the SCG link occurs (1g-10), the terminal may perform data transmission to the MCG for the configured split DRB (1g-20). Specifically, data may be transmitted to the MCG for the split DRB set by one of the following methods.

-The primary RLC bearer of split DRB is set to MCG RLC. The primary RLC bearer refers to an RLC bearer used for transmission when the amount of data to be transmitted by the split DRB is less than a preset threshold (ul-dataSplitThreshold). For this reason, the UE preferentially uses the MCG RLC bearer for transmission.

-Change the split DRB's ul-dataSplitThreshold to 0 or a preset finite value. Accordingly, the use of the secondary RLC bearer can be quickly started, and if the MCG RLC bearer is a secondary RLC bearer, it can be quickly transmitted to the MCG RLC bearer by a small ul-dataSplitThreshold value.

-Enable packet redundancy for split DRB. Accordingly, the PDCP layer duplicates a packet to be transmitted and transmits the same duplicate packet to the primary RLC and the secondary RLC, respectively, thereby enabling transmission to the MCG RLC bearer.

-For split DRB, the PDCP layer sends a packet to the MCG RLC regardless of the existing setting. Accordingly, it is possible to enable transmission to the MCG RLC regardless of the setting of the split DRB.

When the UE performs data transmission to the MCG for the split DRB by one of the above methods, the configuration may be maintained only in OOS or SCG RLF situations in which the SCG link cannot perform normal transmission/reception. That is, data transmission to the MCG can be enabled until the regression condition for returning to the existing setting is satisfied.

The session condition for returning to the existing setting may be a condition set in advance. For example, a case in which the UE returns to a state in which normal transmission/reception is possible by satisfying an IS (In-sync) condition, or a case in which the SCG link is restored by receiving an RRC reconfiguration message from the base station may be an existing set regression condition.

Here, the IS can be defined to recognize that the IS has occurred when the terminal satisfies a specific condition by defining a condition of the IS in an actual communication protocol and to perform an operation after the IS. In some embodiments, when the virtual decoding failure probability of the PDCCH is less than a certain value, it may be defined as IS. When IS occurs, it may be assumed that normal transmission/reception of DRB data transmitted to the cell or cell group in which the IS occurs can be performed.

The terminal checks whether the existing configuration regression condition is satisfied (1g-30), and if it satisfies the existing configuration regression condition, it can return to the existing configuration and perform transmission (1g-40).

Otherwise, if the existing set regression condition is not satisfied, the MCG transmission of the split DRB can be performed as set in step (1g-20).

Meanwhile, although the present disclosure has described the operation of the terminal as an example, the above method may also be applied to a base station.

1H shows a method of preventing transmission delay due to MCG failure proposed in the present invention.

As described in FIG. 1D, if data transmission to the MCG link is not normally performed after the MCG failure, this may lead to deterioration of the quality of user service. In order to prevent this problem, when the MCG link is not good, it is necessary to continuously perform data transmission using the SCG link.

To this end, when an MCG failure occurs (1h-10), the terminal may perform data transmission to the SCG for the configured split DRB (1h-20). Specifically, data can be transmitted to the SCG for a split DRB set by one of the following methods.

-Set the primary RLC bearer of split DRB to SCG RLC. The primary RLC bearer refers to an RLC bearer used for transmission when the amount of data to be transmitted by the split DRB is less than a preset threshold (ul-dataSplitThreshold). For this reason, the UE preferentially uses the SCG RLC bearer for transmission.

-Change the split DRB's ul-dataSplitThreshold to 0 or a preset finite value. Accordingly, the use of the secondary RLC bearer can be quickly started, and if the SCG RLC bearer is a secondary RLC bearer, it can be quickly transmitted to the SCG RLC bearer by a small ul-dataSplitThreshold value.

-Enable packet redundancy for split DRB. Accordingly, the PDCP layer duplicates a packet to be transmitted and transmits the same duplicate packet to the primary RLC and the secondary RLC, respectively, thereby enabling transmission to the SCG RLC bearer.

-For split DRB, the PDCP layer sends a packet to the SCG RLC regardless of the existing settings. For this reason, it is possible to enable transmission to the SCG RLC regardless of the setting of the split DRB.

When the UE performs data transmission to the SCG for the split DRB by one of the above methods, the setting may be maintained only in the MCG RLF situation in which the MCG link cannot perform normal transmission/reception. That is, data transmission to the SCG may be enabled until the regression condition for returning to the existing setting is satisfied.

The session condition for returning to the existing setting may be a condition set in advance. For example, a case in which the MCG link is restored by the UE receiving an RRC reconfiguration message from the base station may be an existing set regression condition.

The UE checks whether or not the existing configuration regression condition is satisfied (1h-30), and if the existing configuration regression condition is satisfied, it can return to the existing configuration and perform transmission (1h-40).

Otherwise, if the existing set regression condition is not satisfied, the split DRB SCG transmission can be performed as set in step (1h-20).

Meanwhile, although the present disclosure has described the operation of the terminal as an example, the above method may also be applied to a base station.

1I shows a method for preventing transmission delay due to SCG failure proposed in the present invention.

As described in FIG. 1E, when data transmission to the SCG link is not normally performed after SCG failure, this may lead to a degradation of the quality of user service. In order to prevent this problem, when the SCG link is not good, it is necessary to continuously perform data transmission using the MCG link.

To this end, when an SCG failure occurs (1i-10), the terminal may perform data transmission to the MCG for the configured split DRB (1i-20). Specifically, data may be transmitted to the MCG for the split DRB set by one of the following methods.

-The primary RLC bearer of split DRB is set to MCG RLC. The primary RLC bearer refers to an RLC bearer used for transmission when the amount of data to be transmitted by the split DRB is less than a preset threshold (ul-dataSplitThreshold). For this reason, the UE preferentially uses the MCG RLC bearer for transmission.

-Change the split DRB's ul-dataSplitThreshold to 0 or a preset finite value. Accordingly, the use of the secondary RLC bearer can be quickly started, and if the MCG RLC bearer is a secondary RLC bearer, it can be quickly transmitted to the MCG RLC bearer by a small ul-dataSplitThreshold value.

-Enable packet redundancy for split DRB. Accordingly, the PDCP layer duplicates a packet to be transmitted and transmits the same duplicate packet to the primary RLC and the secondary RLC, respectively, thereby enabling transmission to the MCG RLC bearer.

-For split DRB, the PDCP layer sends a packet to the MCG RLC regardless of the existing setting. Accordingly, it is possible to enable transmission to the MCG RLC regardless of the setting of the split DRB.

When the terminal performs data transmission to the MCG for the split DRB by one of the above methods, the above configuration may be maintained only in the SCG RLF situation in which the SCG link cannot perform normal transmission/reception. That is, data transmission to the MCG can be enabled until the regression condition for returning to the existing setting is satisfied.

The session condition for returning to the existing setting may be a condition set in advance. For example, a case in which the SCG link is restored by receiving the RRC reconfiguration message from the base station may be an existing setup regression condition.

The UE checks whether the existing configuration regression condition is satisfied (1i-30), and if the existing configuration regression condition is satisfied, it can return to the existing configuration and perform transmission (1i-40).

Otherwise, if the existing set regression condition is not satisfied, the MCG transmission of the split DRB can be performed as set in step (1i-20).

Meanwhile, although the present disclosure has described the operation of the terminal as an example, the above method may also be applied to a base station.

1j shows an RRC configuration process of a base station and a terminal.

Connection setup for performing communication between the terminal 1j-10 and the base station 1j-20 is performed by the base station 1j-20 including the related configuration information in an RRC configuration or reconfiguration message (1j-30 ).

The RRC configuration message may include information on which SRBs and DRBs are to be set and values of timers and parameters necessary for the configuration. In addition, it is also possible to set up a dual connection with MCG and SCG, and in this case, it can be set to perform fast recovery by using the SCG to recover the link when the MCG fails.

And, as suggested in Figs. 1f, 1g, 1h, 1i, 1k, and 1l of the present invention, transmission of split DRB data to a cell group capable of normal transmission, that is, changing the transmission path of data other than the existing configuration May be. If the transmission of split DRB data to a cell group capable of transmission is operated by the transmission timers of FIGS. 1K and 1L, the length of the MCG transmission timer and the length of the SCG transmission timer may be set.

1K shows a method for preventing transmission delay due to MCG failure proposed in the present invention.

As described in FIG. 1D, if data transmission to the MCG link is not normally performed after the MCG failure, this may lead to deterioration of the quality of user service. In order to prevent this problem, when the MCG link is not good, it is necessary to continuously perform data transmission using the SCG link.

In order to set the time point at which data transmission is performed using the SCG link, FIG. 1K proposes a method of setting the MCG transmission timer. The MCG transmission timer may be set to expire when the MCG link state starts at a time when it is difficult to perform transmission and reception normally, and when the MCG link state continues below a certain level for a certain time. For this reason, when the MCG link state becomes less than a certain level by the length of the MCG transmission timer, the split DRB can perform data transmission to the SCG.

The start time of the MCG transmission timer may be started when the MCG link enters an out-of-sync (OOS) state or at an MCG failure time such as an MCG RLF. After the MCG transmission timer starts, when the state of the MCG link is restored to a state in which normal transmission/reception is possible, or when an RRC reset message is received from the base station, the MCG transmission timer may be stopped.

If the MCG transmission timer expires (1k-10), the UE may perform data transmission to the SCG for the configured split DRB (1k-20). Specifically, data can be transmitted to the SCG for a split DRB set by one of the following methods.

-Set the primary RLC bearer of split DRB to SCG RLC. The primary RLC bearer refers to an RLC bearer used for transmission when the amount of data to be transmitted by the split DRB is less than a preset threshold (ul-dataSplitThreshold). For this reason, the UE preferentially uses the SCG RLC bearer for transmission.

-Change the split DRB's ul-dataSplitThreshold to 0 or a preset finite value. As a result, the use of the secondary RLC bearer can be quickly started, and if the SCG RLC bearer is a secondary RLC bearer, it can be quickly transmitted to the SCG RLC bearer by a small ul-dataSplitThreshold value.

-Enable packet redundancy for split DRB. Accordingly, the PDCP layer duplicates a packet to be transmitted and transmits the same duplicate packet to the primary RLC and the secondary RLC, respectively, thereby enabling transmission to the SCG RLC bearer.

-For split DRB, the PDCP layer sends a packet to the SCG RLC regardless of the existing settings. For this reason, it is possible to enable transmission to the SCG RLC regardless of the setting of the split DRB.

When the UE performs data transmission to the SCG for the split DRB by one of the above methods, the setting may be maintained only in the MCG RLF situation in which the MCG link cannot perform normal transmission/reception. That is, data transmission to the SCG may be enabled until the regression condition for returning to the existing setting is satisfied.

The session condition for returning to the existing setting may be a condition set in advance. For example, a case in which the MCG link is restored by the UE receiving an RRC reconfiguration message from the base station may be an existing set regression condition.

The terminal checks whether the existing configuration regression condition is satisfied (1k-30), and if the existing configuration regression condition is satisfied, it can return to the existing configuration and perform transmission (1k-40).

Otherwise, if the existing set regression condition is not satisfied, the split DRB SCG transmission can be performed as set in step (1k-20).

Meanwhile, although the present disclosure has described the operation of the terminal as an example, the above method may also be applied to a base station.

1L shows a method for preventing transmission delay due to SCG failure proposed in the present invention.

As described in FIG. 1E, when data transmission to the SCG link is not normally performed after SCG failure, this may lead to a degradation of the quality of user service. In order to prevent this problem, when the SCG link is not good, it is necessary to continuously perform data transmission using the MCG link.

In order to set the time point at which data transmission is performed using the MCG link, FIG. 1L proposes a method of setting an SCG transmission timer. The SCG transmission timer may be set to expire when the SCG link state starts at a time when it is difficult to perform transmission and reception normally, and when the SCG link state continues below a certain level for a certain time. For this reason, when the SCG link state becomes less than a certain level by the length of the SCG transmission timer, the split DRB can perform data transmission to the MCG.

The start time of the SCG transmission timer may be started when the SCG link enters an OOS (Out-of-sync) state or at an SCG failure time such as SCG RLF. After the SCG transmission timer starts, when the state of the SCG link is restored to a state in which normal transmission and reception is possible, or when an RRC reset message is received from the base station, the SCG transmission timer may be stopped.

If the SCG transmission timer expires (1l-10), the terminal may perform data transmission to the MCG for the configured split DRB. (1l-20) Specifically, data transmission to the MCG may be enabled for a split DRB set by one of the following methods.

- The primary RLC bearer of the split DRB is set to MCG RLC. The primary RLC bearer refers to an RLC bearer used for transmission when the amount of data to be transmitted by the split DRB is less than a preset threshold (ul-dataSplitThreshold). For this reason, the UE preferentially uses the MCG RLC bearer for transmission.

- Change the split DRB's ul-dataSplitThreshold to 0 or a preset finite value. Accordingly, the use of the secondary RLC bearer can be quickly started, and if the MCG RLC bearer is a secondary RLC bearer, it can be quickly transmitted to the MCG RLC bearer by a small ul-dataSplitThreshold value.

- Packet redundancy is enabled for split DRB. Accordingly, the PDCP layer duplicates a packet to be transmitted and transmits the same duplicate packet to the primary RLC and the secondary RLC, respectively, thereby enabling transmission to the MCG RLC bearer.

- For split DRB, the PDCP layer sends a packet to the MCG RLC regardless of the existing setting. Accordingly, it is possible to enable transmission to the MCG RLC regardless of the setting of the split DRB.

When the terminal performs data transmission to the MCG for the split DRB by one of the above methods, the above configuration may be maintained only in the SCG RLF situation in which the SCG link cannot perform normal transmission/reception. That is, data transmission to the MCG can be enabled until the regression condition for returning to the existing setting is satisfied.

The session condition for returning to the existing setting may be a condition set in advance. For example, a case in which the SCG link is restored by receiving the RRC reconfiguration message from the base station may be an existing setup regression condition.

The terminal checks whether the existing configuration regression condition is satisfied (1l-30), and if the existing configuration regression condition is satisfied, it can return to the existing configuration and perform transmission (1l-40).

Otherwise, if the existing set regression condition is not satisfied, the MCG transmission of the split DRB can be performed as set in step (1l-20).

Meanwhile, although the present disclosure has described the operation of the terminal as an example, the above method may also be applied to a base station.

1M is a diagram showing the structure of a base station according to an embodiment of the present invention.

Referring to FIG. 1M, the base station may include a transceiver unit (1m-10), a control unit (1m-20), and a storage unit (1m-30). In the present invention, the control unit 1m-20 may be defined as a circuit or application specific integrated circuit or at least one processor.

The transceiving unit 1m-10 may transmit and receive signals with other network entities. The transmission/reception unit 1m-10 may transmit system information to the terminal, for example, and may transmit a synchronization signal or a reference signal.

The controller 1m-20 may control the overall operation of the base station according to the embodiment proposed in the present invention. For example, the controller 1m-20 may control a signal flow between blocks to perform an operation according to the above-described flowchart.

The storage unit 1m-30 may store at least one of information transmitted and received through the transmission/reception unit 1m-10 and information generated through the control unit 1m-20.

1N is a diagram showing the structure of a terminal according to an embodiment of the present invention.

Referring to FIG. 1N, the terminal may include a transmission/reception unit 1n-10, a control unit 1n-20, and a storage unit 1n-30. In the present invention, the control unit may be defined as a circuit or an application-specific integrated circuit or at least one processor.

The transceiving unit 1n-10 may transmit and receive signals with other network entities. The transceiver 1n-10 may receive system information from, for example, a base station, and may receive a synchronization signal or a reference signal.

The controller 1n-20 may control the overall operation of the terminal according to the embodiment proposed in the present invention. For example, the controller 1n-20 may control a signal flow between blocks to perform an operation according to the above-described flowchart.

The storage unit 1n-30 may store at least one of information transmitted and received through the transmission/reception unit 1n-10 and information generated through the control unit 1n-20.

In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

2A shows a scenario for performing communication between terminals in V2X (vehicular to everything) communication. In V2X communication, it is assumed that the V2X terminals 2a-10, 2a-20, and 2a-30 communicate without going through a base station. At this time, the transmission method may be one of the following three types.

- Unicast: One-to-one (1-1) communication between transmitting and receiving terminals

- Multicast: One-to-many communication between a transmitting terminal and a plurality of receiving terminals

- Broadcast: One-to-many (1-many) communication between a transmitting terminal and a number of unspecified receiving terminals

Which of the above methods is to be transmitted may be determined by the characteristics of the traffic to be transmitted or the characteristics of the transmitting/receiving V2X terminal. In some embodiments, such a determination may be made by the base station and transmitted to the terminal through RRC configuration or the like. Since this V2X communication is based on communication between terminals, it may be performed in a connected mode within the coverage of the base station, but in an idle mode or an inactive mode in which the connection with the base station is released. It is possible. In addition, V2X communication is possible if it has a link state capable of performing V2X communication even in an OOC (Out-of-coverage) state beyond the coverage of the base station. Among these, when using the Unicast method, it can be assumed that two V2X terminals transmit and receive data, and by various methods, the transmitting terminal and the receiving terminal, parameters to be used in Unicast communication, timers, etc. Settings can be set. V2X communication is also called SideLink, because communication is performed between terminals without going through a base station. A radio bearer through which the UE communicates in the sidelink is referred to as a sidelink radio bearer (SLRB).

Regardless of which transmission method is used, in order to support V2X communication, the V2X terminal (2a-10) in charge of transmitting transmits data for V2X communication to one or more receiving V2X terminals (2a-20, 2a-30). I can. In this case, only terminals authorized to receive the data transmitted by the corresponding transmitting terminal may receive data. If V2X communication is performed within the coverage of the base station, the base station 2a-40 may be in charge of controlling the V2X communication. In this case, the role that the base station can play may be at least one of RRC connection configuration, radio resource allocation (frequency and time resource), transmission method configuration, radio bearer configuration, and quality of service (QoS).

2B shows an operation of setting and releasing a sidelink radio bearer (SLRB) for V2X communication.

In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. The first terminal 2b-10 may transmit sidelink terminal information 2b-40 of the first terminal to the base station 2b-30 in order to perform sidelink communication with the second terminal 2b-20. The corresponding sidelink terminal information (2b-40) may include at least one of UE capability of the terminal, a preferred transmission method (Unicast, Multicast, Broadcast, etc.), traffic information to be transmitted, and a list of receiving terminals. The fact that the terminal can transmit the sidelink terminal information (2b-40) to the base station may mean that the terminal is located within the coverage of the base station.

The base station 2b-30 may set a sidelink radio bearer based on information such as sidelink terminal information 2b-40 transmitted by the terminal. The configuration of the sidelink radio bearer may be transmitted by the base station to the terminal using an RRC configuration or reconfiguration message (2b-50).

The RRC configuration or reconfiguration message may include information on the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or how to determine the inactive state so that the terminal can determine the inactive state of the sidelink radio bearer of the terminal. have.

In the embodiment of FIG. 2B, it is shown that the base station 2b-30 transmits an RRC configuration message to one terminal 2b-10 to set the sidelink radio bearer. However, all terminals 2b- 10, 2b-20), that is, an RRC configuration message may be transmitted to both the transmitting terminal and the receiving terminal.

Thereafter, the first terminal may transmit the configuration information of the sidelink radio bearer set by the first terminal and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message (2b-60). The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal.

After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. You can (2b-70).

After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission by using the configured sidelink radio bearer and the receiving terminal to perform reception (2b-80). If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal may perform both transmission and reception.

How long to maintain the configured sidelink radio bearer and by what conditions to release it can be determined by determining the inactivity of the traffic (2b-90). In the embodiment of FIG. 2B, an operation of determining an inactive state in the first terminal, which is one of the terminals performing sidelink transmission and reception, is shown. At this time, the criterion of the first terminal may be at least one of a transmitting terminal, a terminal receiving RRC configuration from a base station, a terminal sending an SLRB synchronization message, or a terminal setting an SLRB.

The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation.

When the first terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, an inactive state indication message for reporting the inactive state of the corresponding radio bearer may be transmitted to the base station (2b-100). The inactive state indication message indicates that traffic has become inactive in a specific sidelink radio bearer of the terminal or in a Unicast connection between the first terminal and the second terminal.

If an inactive state of a specific sidelink radio bearer is notified, an SLRB identifier (Identifier, ID) may be included to indicate which sidelink radio bearer is inactive, or a QoS flow identifier (QFI) to indicate which QoS flow is inactive. ) Can be included. In the case of a deactivation indication message, it may be transmitted using a PC5 RRC message in an RRC message format. However, according to an embodiment, it may be transmitted in the form of a control protocol data unit (PDU) of a service data adaptation protocol (SDAP) or packet data convergence protocol (PDCP).

The base station 2b-30 may release the sidelink radio bearer based on information such as an inactive state indication message 2b-100 received from the terminal. The message for releasing the sidelink radio bearer may be transmitted by the base station to the terminal using an RRC configuration or reconfiguration message (2b-110).

In the embodiment of Figure 2b, the base station (2b-30) shows that the release of the sidelink radio bearer by transmitting an RRC configuration message to one terminal (2b-10), all the terminals (2b) to release the sidelink radio bearer. -10, 2b-20), that is, an RRC configuration message may be transmitted to both the transmitting terminal and the receiving terminal.

Thereafter, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message (2b-120). The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular may include an SLRB identifier to indicate which sidelink radio bearer to release.

The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed (2b-130). The SLRB synchronization message and SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in the form of an RRC message. However, depending on the embodiment, it may be transmitted in the form of a control PDU of SDAP or PDCP.

2C shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication.

In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. The first terminal 2c-10 may transmit sidelink terminal information 2c-40 of the first terminal to the base station 2c-30 in order to perform sidelink communication with the second terminal 2c-20. The corresponding sidelink terminal information 2c-40 may include at least one of UE capability of the terminal, a preferred transmission method (Unicast, Multicast, Broadcast, etc.), traffic information to be transmitted, and a list of receiving terminals. That the terminal can transmit the sidelink terminal information 2c-40 to the base station may mean that the terminal is located within the coverage of the base station.

The base station 2c-30 may set a sidelink radio bearer based on information such as sidelink terminal information 2c-40 transmitted by the terminal. The configuration of the sidelink radio bearer may be transmitted from the base station to the terminal using an RRC configuration or reconfiguration message (2c-50).

The RRC configuration or reconfiguration message may include information on the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or how to determine the inactive state so that the terminal can determine the inactive state of the sidelink radio bearer of the terminal. have.

In the embodiment of FIG. 2c, it is shown that the base station 2c-30 transmits an RRC configuration message to one terminal 2c-10 to set the sidelink radio bearer, but all the terminals 2c- 10, 2c-20), that is, an RRC configuration message may be transmitted to both the transmitting terminal and the receiving terminal.

Thereafter, the first terminal may transmit the configuration information of the sidelink radio bearer set by the first terminal and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message (2c-60). The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal.

After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. You can (2c-70).

After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission by using the configured sidelink radio bearer and the receiving terminal to perform reception (2c-80). If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal may perform both transmission and reception.

How long to maintain the configured sidelink radio bearer and by what conditions to release it can be determined by determining the inactive state of traffic (2c-90). In the embodiment of FIG. 2C, an operation of determining an inactive state in a first terminal, which is one of the terminals performing sidelink transmission and reception, is shown. At this time, the criterion of the first terminal may be at least one of a transmitting terminal, a terminal receiving RRC configuration from a base station, a terminal sending an SLRB synchronization message, or a terminal setting an SLRB.

The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation.

When the first terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, the first terminal may release the configured sidelink radio bearer. In order to release the radio bearer, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message (2c-120). The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular, includes an SLRB identifier to indicate which sidelink radio bearer to release, or an inactive state of a QoS flow. It may also include a QFI (QoS Flow Identifier) to indicate whether it is recognized.

The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed (2c-130). The SLRB synchronization message and SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in the form of an RRC message. However, depending on the embodiment, it may be transmitted in the form of a control PDU of SDAP or PDCP.

2D shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication.

In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. The first terminal 2d-10 may transmit sidelink terminal information 2d-40 of the first terminal to the base station 2d-30 in order to perform sidelink communication with the second terminal 2d-20. The corresponding sidelink terminal information (2d-40) may include at least one of UE capability of the terminal, a preferred transmission method (Unicast, Multicast, Broadcast, etc.), traffic information to be transmitted, and a list of receiving terminals. The fact that the terminal can transmit the sidelink terminal information (2d-40) to the base station may mean that the terminal is located within the coverage of the base station.

The base station 2d-30 may set a sidelink radio bearer based on information such as sidelink terminal information 2d-40 transmitted by the terminal. The configuration of the sidelink radio bearer may be transmitted from the base station to the terminal using an RRC configuration or reconfiguration message (2d-50).

The RRC configuration or reconfiguration message may include information on the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or how to determine the inactive state so that the terminal can determine the inactive state of the sidelink radio bearer of the terminal. have.

In the embodiment of FIG. 2d, the base station 2d-30 transmits an RRC configuration message to one terminal 2d-10 to set the sidelink radio bearer. However, all terminals 2d-30 to set the sidelink radio bearer (2d- 10, 2d-20), that is, an RRC configuration message may be transmitted to both the transmitting terminal and the receiving terminal.

Thereafter, the first terminal may transmit the configuration information of the sidelink radio bearer set by itself and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message (2d-60). The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal.

After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. You can (2d-70).

After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission by using the configured sidelink radio bearer and the receiving terminal to perform reception (2d-80). If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal may perform both transmission and reception.

How long to maintain the configured sidelink radio bearer and by what conditions to release it can be determined by determining the inactive state of traffic (2d-90).

The embodiment of FIG. 2D shows an operation of determining an inactive state in a second terminal, which is one of the terminals performing sidelink transmission and reception. At this time, the reference of the second terminal may be at least one of a receiving terminal, a terminal not receiving RRC configuration from a base station, a terminal receiving an SLRB synchronization message, or a terminal receiving SLRB configuration from the first terminal.

The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation.

When the second terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, an inactive state indication message reporting the inactive state of the corresponding radio bearer may be transmitted to the base station (2d-100). The inactive state indication message indicates that traffic has become inactive in a specific sidelink radio bearer of the terminal or in a Unicast connection between the first terminal and the second terminal.

If an inactive state of a specific sidelink radio bearer is notified, an SLRB identifier (Identifier, ID) may be included to indicate which sidelink radio bearer is inactive, or a QoS flow identifier (QFI) to indicate which QoS flow is inactive. ) Can be included. In the case of a deactivation indication message, it may be transmitted using a PC5 RRC message in an RRC message format. However, depending on the embodiment, the control PDU of SDAP or PDCP may be transmitted.

The base station 2d-30 may release the sidelink radio bearer based on information such as an inactive state indication message 2d-100 received from the terminal. The message for releasing the sidelink radio bearer may be transmitted by the base station to the first terminal using an RRC configuration or reconfiguration message (2d-110).

Here, the first terminal may mean a terminal receiving an existing RRC configuration message (2d-50) from the base station. In the embodiment of Figure 2d, the base station (2d-30) shows that the release of the sidelink radio bearer by transmitting an RRC configuration message to one terminal (2d-10), all the terminals (2d) to release the sidelink radio bearer. -10, 2d-20), that is, an RRC configuration message may be transmitted to both the transmitting terminal and the receiving terminal.

Thereafter, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message (2d-120). The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular may include an SLRB identifier to indicate which sidelink radio bearer to release.

The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed. (2d-130) The SLRB synchronization message and the SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in an RRC message format. However, depending on the embodiment, it may be transmitted in the form of a control PDU of SDAP or PDCP.

2E shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication. In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. The first terminal 2e-10 may transmit sidelink terminal information 2e-40 of the first terminal to the base station 2e-30 in order to perform sidelink communication with the second terminal 2e-20. The corresponding sidelink terminal information 2e-40 may include at least one of UE capability of the terminal, a preferred transmission method (Unicast, Multicast, Broadcast, etc.), traffic information to be transmitted, and a list of receiving terminals. That the terminal can transmit the sidelink terminal information (2e-40) to the base station may mean that the terminal is located within the coverage of the base station.

The base station 2e-30 may set a sidelink radio bearer based on information such as sidelink terminal information 2e-40 transmitted by the terminal. The configuration of the sidelink radio bearer may be transmitted from the base station to the terminal using an RRC configuration or reconfiguration message (2e-50).

The RRC configuration or reconfiguration message may include information on the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or how to determine the inactive state so that the terminal can determine the inactive state of the sidelink radio bearer of the terminal. have.

In the embodiment of FIG. 2e, it is shown that the base station 2e-30 transmits an RRC configuration message to one terminal 2e-10 to configure the sidelink radio bearer, but all terminals 2e- 10, 2e-20), that is, an RRC configuration message may be transmitted to both the transmitting terminal and the receiving terminal.

Thereafter, the first terminal may transmit the configuration information of the sidelink radio bearer set by the first terminal and the sidelink configuration information applied by the first terminal to the second terminal using the SLRB synchronization message. (2e-60) The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal.

After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. Can be (2e-70).

After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission by using the configured sidelink radio bearer and the receiving terminal to perform reception. (2e-80) If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal can perform both transmission and reception.

How long to maintain the configured sidelink radio bearer or to release it under what conditions can be determined by determining the inactive state of traffic (2e-90). The embodiment of FIG. 2E shows an operation of determining an inactive state in a second terminal, which is one of the terminals performing sidelink transmission and reception. At this time, the reference of the second terminal may be at least one of a receiving terminal, a terminal not receiving RRC configuration from a base station, a terminal receiving an SLRB synchronization message, or a terminal receiving SLRB configuration from the first terminal.

The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation.

When the second terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, an inactive state indication message for reporting the inactive state of the corresponding radio bearer may be transmitted to the first terminal (2e-100). The inactive state indication message indicates that traffic has become inactive in a specific sidelink radio bearer of the terminal or in a Unicast connection between the first terminal and the second terminal. If an inactive state of a specific sidelink radio bearer is notified, an SLRB identifier (Identifier, ID) may be included to indicate which sidelink radio bearer is inactive, or a QoS flow identifier (QFI) to indicate which QoS flow is inactive. ) Can be included.

In the case of a deactivation indication message, it may be transmitted using a PC5 RRC message in an RRC message format. However, depending on the embodiment, it may be transmitted in the form of a control PDU of SDAP or PDCP. In the embodiment of FIG. 2e, when the second terminal transmits an inactive state indication message (2e-100) to the first terminal, the second terminal cannot release the configured sidelink radio bearer or the Unicast sidelink connection may be released. It may be because there is no.

The first terminal may release the sidelink radio bearer based on information such as an inactive state indication message (2e-100) sent from the second terminal. In order to release the radio bearer, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message (2e-120). The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular, includes an SLRB identifier to indicate which sidelink radio bearer to release, or an inactive state of a QoS flow. It may also include a QFI (QoS Flow Identifier) to indicate whether it is recognized.

The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed (2e-130). The SLRB synchronization message and SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in the form of an RRC message. However, depending on the embodiment, it may be transmitted in the form of a control PDU of SDAP or PDCP.

2F shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication.

In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. The first terminal 2f-10 may transmit sidelink terminal information 2f-40 of the first terminal to the base station 2f-30 in order to perform sidelink communication with the second terminal 2f-20. The corresponding sidelink terminal information (2f-40) may include at least one of UE capability of the terminal, a preferred transmission method (Unicast, Multicast, Broadcast, etc.), traffic information to be transmitted, and a list of receiving terminals. That the terminal can transmit the sidelink terminal information (2f-40) to the base station may mean that the terminal is located within the coverage of the base station.

The base station 2f-30 may set the sidelink radio bearer based on information such as sidelink terminal information 2f-40 transmitted by the terminal. The configuration of the sidelink radio bearer may be transmitted from the base station to the terminal using an RRC configuration or reconfiguration message (2f-50).

The RRC configuration or reconfiguration message may include information on the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or how to determine the inactive state so that the terminal can determine the inactive state of the sidelink radio bearer of the terminal. have.

In the embodiment of FIG. 2f, it is shown that the base station 2f-30 transmits an RRC configuration message to one terminal 2f-10 to set the sidelink radio bearer, but all the terminals 2f-30 to set the sidelink radio bearer (2f- 10, 2f-20), that is, an RRC configuration message may be transmitted to both the transmitting terminal and the receiving terminal.

Thereafter, the first terminal may transmit the configuration information of the sidelink radio bearer set by the first terminal and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message (2f-60). The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal.

After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. You can (2f-70).

After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission using the configured sidelink radio bearer, and the receiving terminal may perform reception (2f-80). If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal may perform both transmission and reception.

How long to maintain the configured sidelink radio bearer and by what conditions to release it can be determined by determining the inactivity of the traffic (2f-90, 2f-110).

In the embodiment of FIG. 2F, both the first terminal and the second terminal performing sidelink transmission and reception determine an inactive state. At this time, the criterion of the first terminal may be a transmitting terminal, a terminal receiving RRC configuration from a base station, a terminal sending an SLRB synchronization message, or a terminal setting an SLRB. The reference of the second terminal may be at least one of a receiving terminal, a terminal not receiving RRC configuration from a base station, a terminal receiving an SLRB synchronization message, or a terminal receiving an SLRB configuration from the first terminal.

The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation.

When the second terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, an inactive state indication message for reporting the inactive state of the corresponding radio bearer may be transmitted to the first terminal (2f-100). The inactive state indication message indicates that traffic has become inactive in a specific sidelink radio bearer of the terminal or in a Unicast connection between the first terminal and the second terminal.

If an inactive state of a specific sidelink radio bearer is notified, a QFI (QoS Flow Identifier) may be included to indicate which sidelink radio bearer is inactive, or to indicate which QoS flow is inactive. ) Can be included. In the case of a deactivation indication message, it may be transmitted using a PC5 RRC message in an RRC message format. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

In the embodiment of FIG. 2f, when the second terminal transmits the inactive state indication message (2f-100) to the first terminal, the second terminal cannot release the configured sidelink radio bearer or the Unicast sidelink connection may be released. It may be because there is no.

The first terminal may also determine the inactive state of the configured sidelink radio bearer. If both the first terminal and the second terminal determine the inactive state of the radio bearer, the first terminal may release the configured sidelink radio bearer. According to an embodiment, the first terminal may determine the inactive state of the radio bearer in the direction transmitted from the first terminal, and the second terminal may determine the inactive state of the radio bearer in the direction transmitted from the second terminal.

In another embodiment, on the contrary, the first terminal may determine the inactive state of the radio bearer in the direction received by the first terminal, and the second terminal may determine the inactive state of the radio bearer in the direction received by the second terminal.

In another embodiment, each terminal may determine the inactive state of which sidelink radio bearer to determine the inactive state by a predetermined method. Degree

In the embodiment of 2f, it is shown that the second terminal first determines the inactive state of the radio bearer, and the first terminal determines the inactive state of the radio bearer, but the two terminals independently determine the inactive state of the radio bearer. It is okay to practice.

The first terminal may release the sidelink radio bearer based on information such as an inactive state indication message (2f-100) sent by the second terminal and a determination of the inactive state of the first terminal. In order to release the radio bearer, the first terminal may transmit information of the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message (2f-120). The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular, includes an SLRB identifier to indicate which sidelink radio bearer to release, or an inactive state of a QoS flow. It may also include a QFI (QoS Flow Identifier) to indicate whether it is recognized.

The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed (2f-130). The SLRB synchronization message and SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in the form of an RRC message. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

2G shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication.

In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. The first terminal 2g-10 may transmit sidelink terminal information 2g-40 of the first terminal to the base station 2g-30 in order to perform sidelink communication with the second terminal 2g-20. The corresponding sidelink terminal information (2g-40) may include at least one of the UE capability of the terminal, a preferred transmission method (Unicast, Multicast, Broadcast, etc.), traffic information to be transmitted, and a list of receiving terminals. The fact that the terminal can transmit sidelink terminal information (2g-40) to the base station may mean that the terminal is located within the coverage of the base station.

The base station (2g-30) may set a sidelink radio bearer based on information such as transmission sidelink terminal information (2g-40) by the terminal. The configuration of the sidelink radio bearer may be transmitted by the base station to the terminal using an RRC configuration or reconfiguration message (2g-50). The RRC configuration or reconfiguration message may include information on the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or how to determine the inactive state so that the terminal can determine the inactive state of the sidelink radio bearer of the terminal. have.

In the embodiment of FIG. 2G, it is shown that the base station 2g-30 transmits an RRC configuration message to one terminal 2g-10 to set the sidelink radio bearer, but all terminals (2g- 10, 2g-20), that is, an RRC configuration message may be transmitted to both the transmitting terminal and the receiving terminal.

Thereafter, the first terminal may transmit configuration information of the sidelink radio bearer set by itself and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message (2g-60).

The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal. After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. Can (2g-70). four

After the configuration of the idlink radio bearer is completed, the first terminal and the second terminal may perform transmission by using the configured sidelink radio bearer and the receiving terminal to perform reception (2g-80). If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal may perform both transmission and reception.

Whether to keep the configured sidelink radio bearer until when and by what conditions to release it can be determined by determining the inactivity of the traffic (2g-90, 2g-110).

In the embodiment of FIG. 2G, both the first terminal and the second terminal performing sidelink transmission and reception determine an inactive state. At this time, the criterion of the first terminal may be at least one of a transmitting terminal, a terminal receiving RRC configuration from a base station, a terminal sending an SLRB synchronization message, or a terminal setting an SLRB.

The reference of the second terminal may be at least one of a receiving terminal, a terminal not receiving RRC configuration from a base station, a terminal receiving an SLRB synchronization message, or a terminal receiving an SLRB configuration from the first terminal.

The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation.

When the second terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, an inactive state indication message for reporting the inactive state of the corresponding radio bearer may be transmitted to the first terminal (2g-100). The inactive state indication message indicates that traffic has become inactive in a specific sidelink radio bearer of the terminal or in a Unicast connection between the first terminal and the second terminal. If an inactive state of a specific sidelink radio bearer is notified, an SLRB identifier (Identifier, ID) may be included to indicate which sidelink radio bearer is inactive, or a QoS flow identifier (QFI) to indicate which QoS flow is inactive. ) Can be included. In the case of a deactivation indication message, it may be transmitted using a PC5 RRC message in an RRC message format. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

In the embodiment of FIG. 2G, when the second terminal transmits an inactive state indication message (2g-100) to the first terminal, the second terminal cannot release the configured sidelink radio bearer or the Unicast sidelink connection may be released. It may be because there is no.

The first terminal may also determine the inactive state of the configured sidelink radio bearer. If both the first terminal and the second terminal determine the inactive state of the radio bearer, the first terminal may inform the base station 2g-30 that the radio bearer is inactive (2g-112).

According to an embodiment, the first terminal may determine the inactive state of the radio bearer in the direction transmitted from the first terminal, and the second terminal may determine the inactive state of the radio bearer in the direction transmitted from the second terminal.

In another embodiment, on the contrary, the first terminal may determine the inactive state of the radio bearer in the direction received by the first terminal, and the second terminal may determine the inactive state of the radio bearer in the direction received by the second terminal.

In another embodiment, each terminal may determine the inactive state of which sidelink radio bearer to determine the inactive state by a predetermined method.

In the embodiment of FIG. 2G, it is shown that the second terminal first determines the inactive state of the radio bearer and the first terminal determines the inactive state of the radio bearer. However, the operation of two terminals independently determining the inactive state of the radio bearer from each other It is okay to perform.

According to the above-described method, when the first terminal determines the inactive state of the configured sidelink radio bearer after receiving the inactive state indication message from the second terminal, it transmits an inactive state indication message reporting the inactive state of the corresponding radio bearer to the base station. Can (2g-112).

The inactive state indication message indicates that traffic has become inactive in a specific sidelink radio bearer of the terminal or in a Unicast connection between the first terminal and the second terminal. If an inactive state of a specific sidelink radio bearer is notified, an SLRB identifier (Identifier, ID) may be included to indicate which sidelink radio bearer is inactive, or a QoS flow identifier (QFI) to indicate which QoS flow is inactive. ) Can be included. In the case of a deactivation indication message, it may be transmitted using a PC5 RRC message in an RRC message format. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

The base station 2g-30 may release the sidelink radio bearer based on information such as an inactive state indication message (2g-112) sent by the terminal. The release of the sidelink radio bearer may be transmitted by the base station to the terminal using an RRC configuration or reconfiguration message (2g-115). 2G shows that the base station 2g-30 releases the sidelink radio bearer by transmitting an RRC configuration message to one terminal 2g-10, but all terminals to release the sidelink radio bearer (2g -10, 2g-20), that is, an RRC configuration message may be transmitted to both the transmitting terminal and the receiving terminal.

Thereafter, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message (2g-120). The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular may include an SLRB identifier to indicate which sidelink radio bearer to release. The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed. (2g-130) SLRB synchronization message and SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in the form of an RRC message. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

2H shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication.

In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method.

If the terminal is not in a connected mode with the base station, that is, in an idle mode or an inactive mode, the terminal cannot directly receive sidelink radio bearer configuration from the base station. In this case, the terminal may receive a system information block (SIB) from the base station to obtain configuration information of a sidelink radio bearer to be set or a condition for configuration (2h-40, 2h-50). The corresponding system information block may include the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or information on how to determine the inactive state so that the terminal can determine the inactive state of the sidelink radio bearer of the terminal.

Since the first terminal and the second terminal may be located within the coverage of different base stations, the system information block (2h-40) received by the first terminal and the system information block (2h-50) received by the second terminal are different. It can be content. The terminal may establish a sidelink connection and establish a sidelink radio bearer when the conditions for establishing a sidelink radio bearer are satisfied based on the information of the system information block received from the base station (2h-60).

When the conditions for establishing the sidelink radio bearer are satisfied, the first terminal can transmit the sidelink radio bearer configuration information set by itself and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message. Yes (2h-60).

The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal.

After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. Can (2h-70). After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission using the configured sidelink radio bearer, and the receiving terminal may perform reception (2h-80). If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal may perform both transmission and reception.

How long to maintain the configured sidelink radio bearer and by what conditions to release it can be determined by determining the inactivity of the traffic (2h-90).

In the embodiment of FIG. 2H, an operation of determining an inactive state in the first terminal, which is one of the terminals performing sidelink transmission and reception, is shown. At this time, the criterion of the first terminal may be a transmitting terminal, a terminal sending an SLRB synchronization message, or a terminal setting an SLRB. The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation. When the first terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, the first terminal may release the configured sidelink radio bearer.

In order to release the radio bearer, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message (2h-120). The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular, includes an SLRB identifier to indicate which sidelink radio bearer to release, or an inactive state of a QoS flow. It may also include a QFI (QoS Flow Identifier) to indicate whether it is recognized. The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed. (2h-130) The SLRB synchronization message and the SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in an RRC message format. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

2i shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication.

In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. If the terminal is not in a connection mode with the base station, that is, in an idle mode or an inactive mode, the terminal cannot directly receive sidelink radio bearer configuration from the base station. In this case, the UE may receive the system information block (SIB) from the base station to obtain configuration information of the sidelink radio bearer to be set or conditions for configuration (2i-40, 2i-50). The corresponding system information block may include the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or information on how to determine the inactive state so that the terminal can determine the inactive state of the sidelink radio bearer of the terminal.

Since the first terminal and the second terminal may be located within the coverage of different base stations, the system information block 2i-40 received by the first terminal and the system information block 2i-50 received by the second terminal are different. It can be content. The terminal may establish a sidelink connection and establish a sidelink radio bearer when the conditions for establishing a sidelink radio bearer are satisfied based on the information of the system information block received from the base station (2i-60).

When the conditions for establishing the sidelink radio bearer are satisfied, the first terminal can transmit the sidelink radio bearer configuration information set by itself and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message. There is (2i-60).

The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal.

After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. I can. (2i-70) After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission by using the configured sidelink radio bearer and the receiving terminal to perform reception. (2i-80) If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal can perform both transmission and reception.

Whether to keep the configured sidelink radio bearer until when and by what conditions to release it can be determined by determining the inactivity of the traffic (2i-90, 2i-110).

In the embodiment of FIG. 2i, both the first terminal and the second terminal performing sidelink transmission and reception determine an inactive state. At this time, the criterion of the first terminal may be a transmitting terminal, a terminal sending an SLRB synchronization message, or a terminal setting an SLRB. The reference of the second terminal may be a receiving terminal, a terminal receiving an SLRB synchronization message, or a terminal receiving an SLRB setting from the first terminal. The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation. When the second terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, an inactive state indication message for reporting the inactive state of the corresponding radio bearer may be transmitted to the first terminal (2i-100).

The inactive state indication message indicates that traffic has become inactive in a specific sidelink radio bearer of the terminal or in a Unicast connection between the first terminal and the second terminal. If an inactive state of a specific sidelink radio bearer is notified, an SLRB identifier (Identifier, ID) may be included to indicate which sidelink radio bearer is inactive, or a QoS flow identifier (QFI) to indicate which QoS flow is inactive. ) Can be included. In the case of a deactivation indication message, it may be transmitted using a PC5 RRC message in an RRC message format. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment. In the embodiment of FIG. 2i, when the second terminal transmits an inactive state indication message (2i-100) to the first terminal, the second terminal cannot release the configured sidelink radio bearer or the Unicast sidelink connection may be released. It may be because there is no.

The first terminal may also determine the inactive state of the configured sidelink radio bearer. If both the first terminal and the second terminal determine the inactive state of the radio bearer, the first terminal may release the configured sidelink radio bearer. According to an embodiment, the first terminal may determine an inactive state of a radio bearer in a direction transmitted from the first terminal, and the second terminal may determine an inactive state of a radio bearer in a direction transmitted from the second terminal. In another embodiment, on the contrary, the first terminal may determine the inactive state of the radio bearer in the direction received by the first terminal, and the second terminal may determine the inactive state of the radio bearer in the direction received by the second terminal. In another embodiment, each terminal may determine the inactive state of which sidelink radio bearer to determine the inactive state by a predetermined method. In the embodiment of Fig. 2i, it is shown that the second terminal first determines the inactive state of the radio bearer and the first terminal determines the inactive state of the radio bearer. However, the operation in which the two terminals independently determine the inactive state of the radio bearer from each other. It is okay to perform.

The first terminal may release the sidelink radio bearer based on information such as an inactive state indication message (2i-100) sent by the second terminal and a determination of the inactive state of the first terminal. In order to release the radio bearer, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message (2i-120). The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular, includes an SLRB identifier to indicate which sidelink radio bearer to release, or an inactive state of a QoS flow. It may also include a QFI (QoS Flow Identifier) to indicate whether it is recognized.

The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed (2i-130). The SLRB synchronization message and SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in the form of an RRC message. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

2j shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication. In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. If the terminal is not in a connected mode with the base station, that is, in an idle mode or an inactive mode, the terminal cannot directly receive sidelink radio bearer configuration from the base station. In this case, the terminal may receive a system information block (SIB) from the base station to obtain configuration information of a sidelink radio bearer to be set or a condition for configuration. (2j-40, 2j-50) In the corresponding system information block, the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or some method determines the inactive state so that the terminal can determine the inactive state of the sidelink radio bearer of the terminal. You can also include information about whether to do it. Since the first terminal and the second terminal may be located within the coverage of different base stations, the system information block 2j-40 received by the first terminal and the system information block 2j-50 received by the second terminal are different. It can be content. The terminal may establish a sidelink connection and establish a sidelink radio bearer when a condition for establishing a sidelink radio bearer is satisfied based on information on a system information block received from the base station. (2j-60)

When the conditions for establishing the sidelink radio bearer are satisfied, the first terminal can transmit the sidelink radio bearer configuration information set by itself and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message. have. (2j-60) The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal. After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. I can. (2j-70) After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission by using the configured sidelink radio bearer and the receiving terminal to perform reception. (2j-80) If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal can perform both transmission and reception.

How long to maintain the configured sidelink radio bearer and by what conditions to release it can be determined by determining the inactivity of the traffic. (2j-90) The embodiment of FIG. 2J shows an operation of determining an inactive state in a second terminal, which is one of the terminals performing sidelink transmission and reception. In this case, the reference of the second terminal may be a receiving terminal, a terminal receiving an SLRB synchronization message, or a terminal receiving an SLRB setting from the first terminal. The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation. When the second terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, an inactive state indication message for reporting the inactive state of the corresponding radio bearer may be transmitted to the first terminal. (2j-100) The inactive state indication message indicates that traffic has become inactive in a specific sidelink radio bearer of the terminal or in the Unicast connection between the first terminal and the second terminal. If an inactive state of a specific sidelink radio bearer is notified, an SLRB identifier (Identifier, ID) may be included to indicate which sidelink radio bearer is inactive, or a QoS flow identifier (QFI) to indicate which QoS flow is inactive. ) Can be included. In the case of a deactivation indication message, it may be transmitted using a PC5 RRC message in an RRC message format. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment. In the embodiment of FIG. 2j, when the second terminal transmits the inactive state indication message (2j-100) to the first terminal, the second terminal cannot release the configured sidelink radio bearer or the Unicast sidelink connection may be released. It may be because there is no.

The first terminal may release the sidelink radio bearer based on information such as an inactive state indication message (2j-100) sent from the second terminal. In order to release the radio bearer, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message. (2j-120) The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular, the SLRB identifier to inform which sidelink radio bearer to release, or It may include a QoS Flow Identifier (QFI) to indicate whether the QoS flow is inactive. The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed. (2j-130) The SLRB synchronization message and the SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in the form of an RRC message. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

2K shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication. In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. If the terminal is in an OOC (Out-of-coverage) state that is out of the coverage of the base station, the terminal receives a direct sidelink radio bearer configuration from the base station or receives a system information block (SIB) to set the sidelink radio bearer. It is impossible to obtain setting information or conditions for setting. In this case, the terminal may set the sidelink radio bearer according to the pre-configuration (2k-40) stored in (2k-10). The preset may include the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or information on how to determine the deactivation state so that the terminal can determine the inactive state of the sidelink radio bearer. The terminal may establish a sidelink connection and establish a sidelink radio bearer when the conditions for establishing a sidelink radio bearer are satisfied based on the preset information. (2k-60)

When the conditions for establishing the sidelink radio bearer are satisfied, the first terminal can transmit the sidelink radio bearer configuration information set by itself and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message. have. (2k-60) The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal. After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. I can. (2k-70) After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission by using the configured sidelink radio bearer, and the receiving terminal to perform reception. (2k-80) If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal can perform both transmission and reception.

How long to maintain the configured sidelink radio bearer and by what conditions to release it can be determined by determining the inactivity of the traffic. (2k-90) In the embodiment of FIG. 2K, the operation of determining an inactive state in the first terminal, which is one of the terminals performing sidelink transmission and reception, is shown. At this time, the criterion of the first terminal may be a transmitting terminal, a terminal sending an SLRB synchronization message, or a terminal setting an SLRB. The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation. When the first terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, the first terminal may release the configured sidelink radio bearer. In order to release the radio bearer, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message. (2k-120) The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular, the SLRB identifier to inform which sidelink radio bearer to release, or It may include a QoS Flow Identifier (QFI) to indicate whether the QoS flow is inactive. The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed. (2k-130) The SLRB synchronization message and the SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in the form of an RRC message. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

2L shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication. In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. If the terminal is in an OOC (Out-of-coverage) state that is out of the coverage of the base station, the terminal receives a direct sidelink radio bearer configuration from the base station or receives a system information block (SIB) to set the sidelink radio bearer. It is impossible to obtain setting information or conditions for setting. In this case, the UE may set the sidelink radio bearer according to the stored pre-configuration (2l-40). The preset may include the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or information on how to determine the deactivation state so that the terminal can determine the inactive state of the sidelink radio bearer. The terminal may establish a sidelink connection and establish a sidelink radio bearer when the conditions for establishing a sidelink radio bearer are satisfied based on the preset information. (2l-60)

When the conditions for establishing the sidelink radio bearer are satisfied, the first terminal can transmit the sidelink radio bearer configuration information set by itself and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message. have. (2l-60) The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal. After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. I can. (2l-70) After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission by using the configured sidelink radio bearer and the receiving terminal to perform reception. (2l-80) If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal can perform both transmission and reception.

How long to maintain the configured sidelink radio bearer and by what conditions to release it can be determined by determining the inactivity of the traffic. (2l-90, 2l-110) In the embodiment of FIG. 2L, both the first terminal and the second terminal performing sidelink transmission and reception determine an inactive state. At this time, the criterion of the first terminal may be a transmitting terminal, a terminal sending an SLRB synchronization message, or a terminal setting an SLRB. The reference of the second terminal may be a receiving terminal, a terminal receiving an SLRB synchronization message, or a terminal receiving an SLRB setting from the first terminal. The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation. When the second terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, an inactive state indication message for reporting the inactive state of the corresponding radio bearer may be transmitted to the first terminal. (2l-100) The corresponding inactive state indication message indicates that traffic is in an inactive state in which traffic no longer occurs in a specific sidelink radio bearer of the terminal or a Unicast connection between the first terminal and the second terminal. If an inactive state of a specific sidelink radio bearer is notified, an SLRB identifier (Identifier, ID) may be included to indicate which sidelink radio bearer is inactive, or a QoS flow identifier (QFI) to indicate which QoS flow is inactive. ) Can be included. In the case of a deactivation indication message, it may be transmitted using a PC5 RRC message in an RRC message format. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment. In the embodiment of FIG. 2L, when the second terminal transmits the inactive state indication message (2l-100) to the first terminal, the second terminal cannot release the configured sidelink radio bearer or the Unicast sidelink connection may be released. It may be because there is no.

The first terminal may also determine the inactive state of the configured sidelink radio bearer. If both the first terminal and the second terminal determine the inactive state of the radio bearer, the first terminal may release the configured sidelink radio bearer. According to an embodiment, the first terminal may determine an inactive state of a radio bearer in a direction transmitted from the first terminal, and the second terminal may determine an inactive state of a radio bearer in a direction transmitted from the second terminal. In another embodiment, on the contrary, the first terminal may determine the inactive state of the radio bearer in the direction received by the first terminal, and the second terminal may determine the inactive state of the radio bearer in the direction received by the second terminal. In another embodiment, each terminal may determine the inactive state of which sidelink radio bearer to determine the inactive state by a predetermined method. In the embodiment of FIG. 2L, it is shown that the second terminal first determines the inactive state of the radio bearer and the first terminal determines the inactive state of the radio bearer. However, the operation of the two terminals independently determining the inactive state of the radio bearer from each other It is okay to perform.

The first terminal may release the sidelink radio bearer based on information such as an inactive state indication message (2l-100) sent by the second terminal and a determination of the inactive state of the first terminal. In order to release the radio bearer, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message. (2l-120) The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular, the SLRB identifier to indicate which sidelink radio bearer to release, or It may include a QoS Flow Identifier (QFI) to indicate whether the QoS flow is inactive. The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed. (2l-130) The SLRB synchronization message and the SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in the form of an RRC message. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

2m shows the setting and release operation of a sidelink radio bearer (SLRB) for V2X communication. In the present invention, Unicast communication is assumed, but it can be applied to a general transmission method. If the terminal is in an OOC (Out-of-coverage) state that is out of the coverage of the base station, the terminal receives a direct sidelink radio bearer configuration from the base station or receives a system information block (SIB) to set the sidelink radio bearer. It is impossible to obtain setting information or conditions for setting. In this case, the terminal can set the sidelink radio bearer according to the pre-configuration (2m-40) stored in (2m-10). The preset may include the length of the SLRB deactivation timer, the length of the sidelink deactivation timer, or information on how to determine the deactivation state so that the terminal can determine the inactive state of the sidelink radio bearer. The terminal may establish a sidelink connection and establish a sidelink radio bearer when the conditions for establishing a sidelink radio bearer are satisfied based on the preset information. (2m-60)

When the conditions for establishing the sidelink radio bearer are satisfied, the first terminal can transmit the sidelink radio bearer configuration information set by itself and the sidelink configuration information applied by the first terminal to the second terminal using an SLRB synchronization message. have. (2m-60) The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal. After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. I can. (2m-70) After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission by using the configured sidelink radio bearer and the receiving terminal to perform reception. (2m-80) If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal can perform both transmission and reception.

How long to maintain the configured sidelink radio bearer and by what conditions to release it can be determined by determining the inactivity of the traffic. (2m-90) The embodiment of FIG. 2M shows an operation of determining an inactive state in a second terminal, which is one of the terminals performing sidelink transmission and reception. In this case, the reference of the second terminal may be a receiving terminal, a terminal receiving an SLRB synchronization message, or a terminal receiving an SLRB setting from the first terminal. The inactive state of traffic may be determined in units of each sidelink radio bearer (SLRB), or may be determined in units of Unicast connection between two terminals performing transmission/reception. Conditions for determining the inactivation of traffic include notifying information that data packets do not arrive at the sidelink radio bearer for a certain period of time, or that data packets no longer occur or arrive at higher layers such as the application layer, or It may be one of the methods of determining that it is the last packet of the corresponding sidelink radio bearer by operation. When the second terminal determines the inactive state of the configured sidelink radio bearer by the above-described method, an inactive state indication message for reporting the inactive state of the corresponding radio bearer may be transmitted to the first terminal. (2m-100) The inactive state indication message indicates that traffic has become inactive in a specific sidelink radio bearer of the terminal or in the Unicast connection between the first terminal and the second terminal. If an inactive state of a specific sidelink radio bearer is notified, an SLRB identifier (Identifier, ID) may be included to indicate which sidelink radio bearer is inactive, or a QoS flow identifier (QFI) to indicate which QoS flow is inactive. ) Can be included. In the case of a deactivation indication message, it may be transmitted using a PC5 RRC message in an RRC message format. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment. In the embodiment of FIG. 2M, when the second terminal transmits an inactive state indication message (2m-100) to the first terminal, the second terminal cannot release the configured sidelink radio bearer or the Unicast sidelink connection may be released. It may be because there is no.

The first terminal may release the sidelink radio bearer based on information such as an inactive state indication message (2m-100) sent from the second terminal. In order to release the radio bearer, the first terminal may transmit information on the sidelink radio bearer to be released to the second terminal using an SLRB synchronization message. (2m-120) The information included in the SLRB synchronization message may include information necessary for the second terminal to release the sidelink radio bearer, and in particular, the SLRB identifier to inform which sidelink radio bearer to release, or It may include a QoS Flow Identifier (QFI) to indicate whether the QoS flow is inactive. The second terminal applies the configuration information to be applied by the second terminal including release of the sidelink radio bearer among the information included in the SLRB synchronization message transmitted by the first terminal, and then transmits the SLRB confirmation message so that the second terminal It can be notified that the release of the radio bearer has been completed. (2m-130) The SLRB synchronization message and the SLRB confirmation message may be transmitted using a sidelink PC5 RRC message in an RRC message format. However, it may be transmitted in the form of a control protocol data unit (PDU) of SDAP (Service Data Adaptation Protocol) or PDCP (Packet Data Convergence Protocol) according to an embodiment.

2n shows an operation of transmitting V2X communication information to a base station and receiving reconfiguration of the base station. If the terminal (2n-10, 2n-20) is not in a connected mode with the base station (2n-30), the idle mode (Idle Mode), the inactive mode (Inactive Mode), the OOC ( Out-of-coverage) state, the terminal cannot directly receive sidelink radio bearer configuration from the base station. (2n-40) Therefore, as described in Figs. 2h, 2i, 2j, 2k, 2l, 2m, the terminal receives a system information block (SIB) from the base station or sets it by pre-configuration. It is possible to obtain configuration information of the sidelink radio bearer or conditions for configuration. In this case, when the conditions for establishing the sidelink radio bearer are satisfied, the UE may establish a sidelink connection and establish a sidelink radio bearer. (2n-60) When the first terminal satisfies the conditions for establishing a sidelink radio bearer, the first terminal sends the configuration information of the sidelink radio bearer set by itself and the sidelink configuration information applied by the first terminal to the second terminal. You can use (2n-60) The information included in the SLRB synchronization message may include information necessary for the second terminal to configure a sidelink radio bearer. In some embodiments, the SLRB synchronization message may serve to establish a sidelink radio bearer between the first terminal and the second terminal. After applying the configuration information to be applied by the second terminal among the information included in the SLRB synchronization message transmitted by the first terminal, the second terminal transmits an SLRB confirmation message to inform that the second terminal has completed the configuration of the sidelink radio bearer. I can. (2n-70) After the configuration of the sidelink radio bearer is completed, the first terminal and the second terminal may perform transmission using the configured sidelink radio bearer, and the receiving terminal may perform reception. (2n-80) If the configured sidelink radio bearer is a Bi-Directional radio bearer, the first terminal and the second terminal can perform both transmission and reception.

Thereafter, when the terminal returns to the connected mode, the terminal may have to transmit information about communication to the base station 2n-30 through the sidelink it is performing. (2n-100) Since the terminal in the connected mode may have to perform sidelink communication including the sidelink radio bearer according to the settings of the base station, the sidelink established or reset by the terminal in idle mode, inactive mode, OOS, etc. The base station knows the information of the radio bearer and can determine whether or not to reset accordingly. The sidelink terminal information message 2n-100 transmitted to the base station after the terminal returns to the connected mode may include a sidelink radio bearer (SLRB) setting value currently configured in the terminal. The setting values include the set SLRB identifier (Identifier), RLC mode, the size of the sequence number being used, the COUNT value, information on the sidelink radio bearer set in which mode, and data processed by the sidelink radio bearer. QFI (QoS Flow Identifier) of, the amount of data processed by the terminal by the sidelink radio bearer before the connection mode, and at least one of the sidelink radio bearer transmission method (Unicast, Broadcast, Multicast, etc.) may be included. . In addition, as information on the sidelink communication being performed, the sidelink connection information performed by the corresponding terminal, the identifier of the counterpart terminal with the sidelink connection, and measurement results for the sidelink connection may be transmitted. Through this, the base station can determine whether to perform reconfiguration of the configured sidelink radio bearer. If the base station needs sidelink communication and reconfiguration of the sidelink radio bearer, it can instruct the necessary reconfiguration using an RRC setup or reconfiguration message. (2n-110)

2O shows an operation method of determining a deactivation state of a sidelink radio bearer by a timer. When it is determined whether data using the sidelink radio bearer set in the terminal no longer occurs, the corresponding sidelink radio bearer may be released or reported to the base station to receive reconfiguration from the base station based on this. To this end, the transmitter or receiver may determine whether data is no longer generated according to whether data to be transmitted or received by the sidelink radio bearer is generated. This can operate on a preset timer in the unit of a sidelink radio bearer. (2o-15, 2o-25, 2o-35) The length of this timer can be determined by a preset stored by the terminal, a system information block transmitted from the base station, an RRC configuration message of the base station, or the decision of the terminal implementation. have. The start of the timer may be started at each transmission of data, and when the transmission of new data to the corresponding sidelink radio bearer is performed during the operation of the timer, the timer running may be restarted. Here, data transmission may mean data transmission in a transmitter and data reception in a receiver. In the embodiment of FIG. 2O, it indicates that the timer is started at the time (2o-10) at which transmission of the first data packet starts. (2o-15) And before this timer expires, the transmission of the second data packet starts (2o-20), indicating that the timer starts again. (2o-25) And before this timer expires, the transmission of the third data packet begins (2o-30), indicating that the timer starts again. After (2o-35), when no more packet transmission occurs, the timer expires, and this can be determined as a deactivated state of the sidelink radio bearer. (2o-90) This coincides with the determination of the deactivation state of the radio bearer described in the descriptions of FIGS. 2B to 2M, and the UE can perform an operation according to it.

In FIG. 2O, the deactivation state of the sidelink radio bearer is determined, but the deactivation state of a specific QoS flow may be determined according to embodiments. At this time, the timer may exist for each QoS flow, and when data transmission of the corresponding QoS flow occurs, the timer may be restarted. Thereafter, when the timer for the corresponding QoS flow expires, it may be determined as a deactivated state in which data of the corresponding QoS flow no longer occurs. In another embodiment, it is also possible to determine a data inactivation state for a sidelink connection between two terminals. At this time, the timer may exist for each sidelink connection between the two terminals, and when data transmission of the corresponding sidelink connection occurs, the timer may be restarted. Thereafter, when the timer for the corresponding sidelink connection expires, it may be determined as an inactive state in which data of the corresponding sidelink connection no longer occurs.

2P shows an operation method of determining a deactivation state of a sidelink radio bearer using a timer.

When it is determined whether data using the sidelink radio bearer set in the terminal no longer occurs, the corresponding sidelink radio bearer may be released or reported to the base station to receive reconfiguration from the base station based on this. To this end, the transmitter or receiver may determine whether the transmitted or received packet is the last packet of the corresponding sidelink radio bearer based on the contents of the generated packet. This can be performed at the application layer of V2X communication or the PC5-S layer, and it is assumed that the packet contents can be grasped at that layer.

In the embodiment of FIG. 2p, when transmission of the first data packet occurs (2p-10), the layer determining whether the packet is the last packet indicates that the corresponding packet is not the last packet.

Thereafter, transmission of the second data packet is started (2p-20), and the layer determining whether the packet is the last packet indicates that the packet is not the last packet. In addition, when transmission of the third data packet is started (2p-30), the layer determining whether the third data packet is the last packet may determine that the corresponding packet is the last packet. In this case, it is possible to determine the inactive state of the corresponding sidelink radio bearer (2p-90). In this case, the layer determining whether the last packet is the last packet may be transmitted to the AS (Access Stratum) layer, so that the AS layer may know whether the sidelink radio bearer is deactivated. This coincides with the determination of the deactivation state of the radio bearer described in the descriptions of FIGS. 2B to 2M, and the terminal can perform an operation according to it.

In FIG. 2P, the deactivation state of the sidelink radio bearer is determined, but the deactivation state of a specific QoS flow may be determined according to embodiments. At this time, the timer may exist for each QoS flow, and when data transmission of the corresponding QoS flow occurs, the timer may be restarted. Thereafter, when the timer for the corresponding QoS flow expires, it may be determined as a deactivated state in which data of the corresponding QoS flow no longer occurs. In another embodiment, it is also possible to determine a data inactivation state for a sidelink connection between two terminals. At this time, the timer may exist for each sidelink connection between the two terminals, and when data transmission of the corresponding sidelink connection occurs, the timer may be restarted. Thereafter, when the timer for the corresponding sidelink connection expires, it may be determined as an inactive state in which data of the corresponding sidelink connection no longer occurs.

2q shows an operation of releasing a sidelink connection between two terminals. After determining the deactivation state of the sidelink radio bearer in the description of FIG. 2O or 2P, the sidelink radio bearer may be released according to a preset condition for a terminal example or a preset base station. (2q-10) At this time, the transmitting terminal or the receiving terminal can check whether there are more sidelink radio bearers established between the two terminals. (2q-20) If there are no more configured sidelink radio bearers, the sidelink connection between the two terminals can be released. (2q-30) If there are more configured sidelink radio bearers, the sidelink connection between the two stages can be maintained. In Figure 2q, the sidelink radio bearer may be an operation limited to the Unicast radio bearer.

2R is a diagram showing the structure of a base station according to an embodiment of the present invention.

Referring to FIG. 2R, the base station may include a transceiver 2r-10, a controller 2r-20, and a storage 2r-30. In the present invention, the control unit 2r-20 may be defined as a circuit or application-specific integrated circuit or at least one processor.

The transceiving unit 2r-10 may transmit and receive signals with other network entities. The transceiver 2r-10 may transmit system information to the terminal, for example, and may transmit a synchronization signal or a reference signal.

The controller 2r-20 may control the overall operation of the base station according to the embodiment proposed in the present invention. For example, the controller 2r-20 may control a signal flow between blocks to perform an operation according to the above-described flowchart.

The storage unit 2r-30 may store at least one of information transmitted and received through the transmission/reception unit 2r-10 and information generated through the control unit 2r-20.

2S is a diagram showing the structure of a terminal according to an embodiment of the present invention.

Referring to FIG. 2S, the terminal may include a transmission/reception unit 2s-10, a control unit 2s-20, and a storage unit 2s-30. In the present invention, the control unit may be defined as a circuit or an application-specific integrated circuit or at least one processor.

The transceiving unit 2s-10 may transmit and receive signals with other network entities. The transceiver 2s-10 may receive system information from, for example, a base station, and may receive a synchronization signal or a reference signal.

The controller 2s-20 may control the overall operation of the terminal according to the embodiment proposed in the present invention. For example, the controller 2s-20 may control a signal flow between blocks to perform an operation according to the above-described flowchart.

The storage unit 2s-30 may store at least one of information transmitted and received through the transmission/reception unit 2s-10 and information generated through the control unit 2s-20.

Claims (1)

In the control signal processing method in a wireless communication system,
Receiving a first control signal transmitted from a base station;
Processing the received first control signal; And
And transmitting a second control signal generated based on the processing to the base station.

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