KR20220117157A - Method and apparatus for relaying public signals in communication system - Google Patents

Abstract

Disclosed is a technology for relaying public signals in a communication system. An operating method of a relay terminal for relaying wireless communication between a base station and a remote terminal in a communication system comprises the steps of: recognizing a relay request of the remote terminal for system information provided by the base station; obtaining the system information from the base station; and transmitting the system information to the remote terminal.

Description

Method and apparatus for relaying common signals in communication systems

The present invention relates to a common signal relay technology in a communication system, and more particularly, to a common signal relay technology in a communication system that allows a common signal to be relayed through a side link.

With the development of information and communication technology, various wireless communication technologies may be developed. As a representative wireless communication technology, there may be long term evolution (LTE), new radio (NR), etc. defined in a 3rd generation partnership project (3GPP) standard. LTE may be one of 4G (4th Generation) wireless communication technologies, and NR may be one of 5G (5th Generation) wireless communication technologies.

For the processing of wireless data rapidly increasing after the commercialization of a 4G communication system (eg, a communication system supporting LTE), a frequency band of a 4G communication system (eg, a frequency band of 6 GHz or less) as well as a 4G communication system A 5G communication system (eg, a communication system supporting NR) using a frequency band (eg, a frequency band of 6 GHz or more) higher than the frequency band of may be considered. The 5G communication system may support enhanced Mobile BroadBand (eMBB), Ultra-Reliable and Low Latency Communication (URLLC), and massive Machine Type Communication (mMTC).

In such a communication system, a side link may be configured between terminals. As such, a terminal adjacent to the base station, that is, a relay terminal, among terminals configured with the side link, may relay data communication between another terminal, that is, a remote terminal and the base station. In this case, the relay terminal may need to transmit a common signal to the remote terminal.

It is an object of the present invention to provide a method and apparatus for relaying a common signal in a communication system that enables a relay terminal to relay a common signal between a base station and a remote terminal through a side link.

In order to achieve the above object, a common signal relay method in a communication system according to a first embodiment of the present invention is an operating method of a relay terminal for relaying wireless communication between a base station and a remote terminal in a communication system, the system provided by the base station recognizing a relay request of the remote terminal for information; obtaining the system information from the base station; and transmitting the system information to the remote terminal.

Here, the step of recognizing the relay request of the remote terminal for the system information provided by the base station may include: receiving a request message notifying the relay request for the system information from the remote terminal; and recognizing a relay request for the system information in the received request message.

Here, the step of recognizing the relay request of the remote terminal for the system information provided by the base station may include: receiving relay request identification information capable of distinguishing the relay request of the remote terminal for the system information from the base station; receiving a discovery message including the relay request identification information from the remote terminal; and recognizing the relay request for the system information by acquiring the relay request identification information from the received discovery message.

Here, the relay request identification information may be an identifier for a request logical channel used by the remote terminal to transmit the discovery message in order to request transmission of the system information.

Here, the relay request identification information may be requested discovery resource information used by the remote terminal to transmit the discovery message to request transmission of the system information.

Here, the step of obtaining the system information from the base station according to the relay request may include: requesting the base station to transmit the system information; and receiving the system information in response to the transmission request from the base station.

Here, the step of requesting transmission of the system information to the base station may include: selecting a first PRACH sequence requesting transmission of the system information designated by the base station from physical random access channel (PRACH) sequences; and transmitting the first PRACH sequence to the base station through a PRACH.

Here, receiving a relay stop request for the system information from the remote terminal; and stopping the transmission of the system information according to the relay stop request.

On the other hand, a common signal relay method in a communication system according to a second embodiment of the present invention for achieving the above object is an operation method of a relay terminal relaying wireless communication between a base station and a remote terminal in a communication system, from the remote terminal receiving information related to a paging operation for receiving a paging message destined for the remote terminal; receiving the paging message from the base station by performing a monitoring operation on the paging occurrence indicated by the association information; determining a destination of the paging message based on information included in the paging message; and when the destination of the paging message is the remote terminal, transmitting the paging message to the remote terminal.

Here, the association information is a remote terminal identifier, and the step of receiving the paging message from the base station by performing a monitoring operation on the paging occurrence indicated by the association information includes the paging error associated with the remote terminal identifier. performing a monitoring operation in and receiving the paging message from the base station in the paging error.

Here, the association information is a remote terminal identifier and a discontinuous reception (DRX) period of the remote terminal, and the step of receiving the paging message from the base station by performing a monitoring operation in the paging occurrence indicated by the association information includes: , performing a monitoring operation on the paging error associated with the remote terminal identifier and the DRX cycle; and receiving the paging message from the base station in the paging error.

Here, the association information is a remote terminal identifier, and the method may further include transmitting the remote terminal identifier to the base station.

Here, in the step of transmitting the paging message to the remote terminal, the relay terminal transmits the paging message to the remote terminal using an individual transmission method, a broadcast transmission method, or a group transmission method. can

Here, receiving a request to stop relaying the paging message from the remote terminal; and stopping relay of the paging message destined for the remote terminal according to the relay stop request.

Meanwhile, in a communication system according to a third embodiment of the present invention for achieving the above object, a common signal relay apparatus is a relay terminal for relaying wireless communication between a base station and a remote terminal in a communication system, comprising: a processor; a memory in electronic communication with the processor; and instructions stored in the memory, wherein when the instructions are executed by the processor, the instructions enable the relay terminal to transmit a relay request of the remote terminal for system information provided by the base station. recognize; obtain the system information from the base station; and cause transmission of the system information to the remote terminal.

Here, when recognizing the relay request of the remote terminal for the system information provided by the base station, the commands include: the relay terminal receives a request message informing of the relay request for the system information from the remote terminal; and cause recognition of the relay request for the system information in the received request message.

Here, when recognizing the relay request of the remote terminal for the system information provided by the base station, the commands identify the relay request by which the relay terminal can distinguish the remote terminal's relay request for system information from the base station receive information; receive a discovery message including the relay request identification information from the remote terminal; and obtain the relay request identification information from the received discovery message to cause recognition of the relay request for the system information.

Here, the relay request identification information may be an identifier for a request logical channel used by the remote terminal to transmit the discovery message in order to request transmission of the system information.

Here, the relay request identification information may be requested discovery resource information used by the remote terminal to transmit the discovery message to request transmission of the system information.

According to the present application, the remote terminal may request relay transmission of system information from the base station to the relay terminal using a request message. In addition, according to the present application, the remote terminal may request relay transmission of system information from the base station to the relay terminal by using the request notifier. In addition, according to the present application, the remote terminal may request relay transmission of system information from the base station to the relay terminal by using a request logical channel in the process of performing a discovery procedure with the relay terminal. In addition, according to the present application, the remote terminal may request relay transmission of system information from the base station by using the requested discovery resource. Accordingly, the relay terminal may receive a relay request for system information of the base station from the remote terminal, obtain the system information from the base station, and transmit the system information to the remote terminal. As such, the relay terminal may relay system information between the base station and the remote terminal. As a result, the remote terminal can acquire the system information of the base station through the relay terminal when out of the communication service area of the base station.

Meanwhile, according to the present application, the remote terminal may request relay transmission of the paging message to the relay terminal. Accordingly, the relay terminal may receive the paging message for the remote terminal from the base station and deliver it to the remote terminal. In this case, the base station may reduce the paging error for the relay terminal to perform a reception operation by using the paging notifier. In addition, the base station may reduce the paging error by sending a paging message for paging the remote terminal to the paging error associated with or mapped to the relay terminal identifier. In this way, as the base station reduces the paging error to be performed by the relay terminal, power of the relay terminal can be reduced.

1 is a conceptual diagram illustrating a first embodiment of a wireless communication network.
2 is a block diagram illustrating a first embodiment of a communication node constituting a wireless communication network.
3 is a conceptual diagram illustrating a first embodiment of a method for a relay terminal to relay data.
4A is a flowchart illustrating a first embodiment of a method for obtaining system information of a remote terminal.
4B is a flowchart illustrating a second embodiment of a method for obtaining system information of a remote terminal.
5 is a flowchart illustrating a first embodiment of a method in which a relay terminal relays on-demand system information.
6 is a flowchart illustrating a second embodiment of a method for a relay terminal to relay on-demand system information.
7 is a flowchart illustrating a first embodiment of a method for relaying a paging message by a relay terminal.
8 is a flowchart illustrating a second embodiment of a method for relaying a paging message by a relay terminal.
9 is a flowchart illustrating a first embodiment of a method for a relay terminal to obtain a terminal identifier.
10 is a flowchart illustrating a second embodiment of a method for a relay terminal to obtain a terminal identifier.
11 is a flowchart illustrating a third embodiment of a method for relaying a paging message by a relay terminal.
12 is a flowchart illustrating a fourth embodiment of a method in which a relay terminal relays a paging message.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

In embodiments of the present application, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B”. Also, in the embodiments of the present application, “at least one of A and B” may mean “at least one of A or B” or “at least one of combinations of one or more of A and B”.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

A wireless communication network to which embodiments according to the present application are applied will be described. A wireless communication network to which embodiments according to the present application are applied is not limited to the content described below, and embodiments according to the present application may be applied to various wireless communication networks. Here, a wireless communication network may be used in the same meaning as a wireless communication system.

1 is a conceptual diagram illustrating a first embodiment of a wireless communication network.

Referring to FIG. 1 , a wireless communication network 100 may include a plurality of communication nodes 110 , 111 , 120 , 121 , 140 , 150 , 180 , 190 , 191 , 192 , 193 , 194 , 195 . . Each of the plurality of communication nodes may support at least one communication protocol. For example, each of the plurality of communication nodes may include a code division multiple access (CDMA)-based communication protocol, a wideband CDMA (WCDMA)-based communication protocol, a time division multiple access (TDMA)-based communication protocol, and a frequency division multiple (FDMA)-based communication protocol. access) based communication protocol, OFDM (orthogonal frequency division multiplexing) based communication protocol, OFDMA (orthogonal frequency division multiple access) based communication protocol, SC (single carrier)-FDMA based communication protocol, NOMA (Non-orthogonal Multiple) Access), a space division multiple access (SDMA)-based communication protocol, etc. may be supported.

The wireless communication network 100 includes a plurality of base stations (BSs) 110 , 111 , 120 , 121 , 140 , 150 , a plurality of user equipments (UEs) 190 , 191 , 192 , 193 , 194, 195, 180). Each of the plurality of base stations 110 , 111 , and 140 may form a macro cell. Each of the plurality of base stations 120 , 121 , and 150 may form a small cell. A plurality of terminals 190 and 191 may belong to a cell coverage of the base station 110 . A plurality of base stations 120 and 121 and a plurality of terminals 191 , 192 , 193 , 194 and 195 may belong to the cell area of the base station 111 . The base station 150 and the plurality of terminals 191 , 192 , and 180 may belong to the cell area of the base station 140 .

A plurality of communication nodes (110, 111, 120, 121, 140, 150, 180, 190, 191, 192, 193, 194, 195) each of the cellular (cellular) communication (eg, 3GPP (3rd generation partnership project) ) may support a radio access protocol standard of a radio access technology based on long term evolution (LTE), LTE-A (advanced), NR (new radio), etc.) defined in the standard. Each of the plurality of base stations 110 , 111 , 120 , 121 , 140 and 150 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110 , 111 , 120 , 121 , 140 , and 150 may be connected to each other through an ideal backhaul or a non-ideal backhaul, and through the ideal backhaul or non-ideal backhaul can exchange information with each other. Each of the plurality of base stations 110 , 111 , 120 , 121 , 140 and 150 may be connected to a core network (not shown) through a backhaul. Each of the plurality of base stations (110, 111, 120, 121, 140, 150) may transmit data received from the core network to the corresponding terminal (190, 191, 192, 193, 194, 195, 180), and the corresponding terminal Data received from (190, 191, 192, 193, 194, 195, 180) may be transmitted to the core network.

A plurality of communication nodes (110, 111, 120, 121, 140, 150, 180, 190, 191, 192, 193, 194, 195) constituting the wireless communication network 100 each have a beamforming function using a multi-antenna. It is possible to exchange signals with other communication nodes without interference with a beam formed using

Each of the plurality of base stations 110, 111, 120, 121, 140, and 150 transmits multiple input multiple output (MIMO) using multiple antennas (eg, single user (SU)-MIMO, multiple users ( multi user, MU-MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission of multiple transmission/reception points, carrier aggregation (CA) transmission, unlicensed band transmission, direct inter-device transmission It may support device to device communication (D2D), proximity services (ProSe), dual connectivity transmission, and the like.

Each of the plurality of base stations 110, 111, 120, 121, 140, 150 is a NodeB, an evolved NodeB, gNB, ng-eNB, a radio base station, an access point, an access node (access node), a node (node), may be referred to as a radio side unit (radio side unit, RSU) and the like. Each of the plurality of terminals 190, 191, 192, 193, 194, 195, 180 is a user equipment (UE), a terminal, an access terminal, a mobile terminal, and a station. , subscriber station, mobile station, portable subscriber station, node, device, internet of thing (IoT) device, mounted module /device/terminal or on board device/terminal, etc.).

A plurality of communication nodes (110, 111, 120, 121, 140, 150, 180, 190, 191, 192, 193, 194, 195) each of the cellular (cellular) communication (eg, 3GPP (3rd generation partnership project) ) may support long term evolution (LTE), LTE-A (advanced), etc.) specified in the standard. Each of the plurality of base stations 110 , 111 , 120 , 121 , 140 and 150 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110 , 111 , 120 , 121 , 140 , 150 may be connected to each other through an ideal backhaul or a non-ideal backhaul, and each other through an ideal backhaul or a non-ideal backhaul information can be exchanged. Each of the plurality of base stations 110 , 111 , 120 , 121 , 140 , and 150 may be connected to a core network (not shown) through an ideal backhaul or a non-ideal backhaul. Each of the plurality of base stations 110, 111, 120, 121, 140, and 150 may transmit a signal received from the core network to the corresponding terminal 190, 191, 192, 193, 194, 195, 180, and the corresponding terminal A signal received from (190, 191, 192, 193, 194, 195, 180) may be transmitted to the core network.

Each of the plurality of base stations 110 , 111 , 120 , 121 , 140 and 150 may support OFDMA-based downlink transmission and may support SC-FDMA-based uplink transmission. In addition, each of the plurality of base stations 110, 111, 120, 121, 140, and 150 transmits multiple input multiple output (MIMO) (eg, single user (SU)-MIMO, multi user (MU)-MIMO, Large-scale (massive MIMO, etc.), CoMP (coordinated multipoint) transmission, carrier aggregation (carrier aggregation) transmission, transmission in an unlicensed band, direct (device to device, D2D) communication between terminals (or, ProSe (proximity) services), etc. Here, each of the plurality of terminals 190, 191, 192, 193, 194, 195, 180 is an operation corresponding to the base station 110, 111, 120, 121, 140, 150, It is possible to perform operations supported by the base stations 110, 111, 120, 121, 140, and 150. The content of the present application is not limited to the above-mentioned terms and applies to radio access technology (RAT). It can be replaced with another term that performs the corresponding function according to the wireless access protocol and the function configuration supporting it.

2 is a block diagram illustrating a first embodiment of a communication node constituting a wireless communication network.

Referring to FIG. 2 , the communication node 200 may include at least one processor 210 , a memory 220 , and a transceiver 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240 , an output interface device 250 , a storage device 260 , and the like. Each of the components included in the communication node 200 may be connected by a bus 270 to communicate with each other.

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

A plurality of communication nodes (110, 111, 120, 121, 140, 150, 180, 190, 191, 192, 193, 194, 195) constituting the wireless communication network 100 and a plurality of communication described in the present application Each of the nodes may be configured as a communication node 200 .

Next, a structure of a radio access protocol that provides a radio access between a base station and a terminal in a radio communication network and a function for each layer can be described. The structure and function of each layer of the radio access protocol are described for the purpose of describing specific embodiments only, and are not intended to limit the present application, and may include changes or substitutions included in the concept and scope of the proposed technology.

The radio access protocol may provide a function for a plurality of communication nodes to exchange data and control information by utilizing radio resources in a radio section, and may be configured hierarchically. In cellular communication (eg, 3rd generation partnership project (3GPP) standard, long term evolution (LTE), LTE-A (advanced), NR (new radio), etc.), the radio access protocol is 1) a physical signal Constructing radio layer 1 (radio layer 1, RL1), 2) can control radio transmission in radio resources shared by a plurality of communication nodes, can transmit data to a counterpart node, and match radio layer 2 (radio layer 2) , RL2), 3) a radio layer 3 (radio layer 3) that controls radio resources such as network information sharing, radio connection management, mobility management, and quality of service (QoS) management to a plurality of communication nodes participating in a wireless network RL3) can be configured.

The radio layer 1 may be a physical layer and may provide a function for data transfer. Radio layer 2 is medium access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP) ) may be composed of sub-layers such as The radio layer 3 may be a radio resource control (RRC) layer and may provide an access-stratum (AS) layer control function.

Operations such as start, stop, reset, restart, or expire of the timer defined in relation to the operation of the timer defined or described in the present application are not separately described. It may mean or include the operation of a timer or a counter for the corresponding timer.

Next, operating methods of a communication node in a wireless communication network may be described. Even when a method (eg, transmission or reception of a signal) performed in a first communication node among communication nodes is described, a second communication node corresponding thereto is a method (eg, a method corresponding to the method performed in the first communication node) For example, reception or transmission of a signal) may be performed. That is, when the operation of the terminal is described, the corresponding base station may perform the operation corresponding to the operation of the terminal. Conversely, when the operation of the base station is described, the corresponding terminal may perform the operation corresponding to the operation of the base station.

On the other hand, the sidelink (sidelink) may be a wireless connection for transmitting data between the terminal and the terminal. Transmission of data may be performed in such a way that a corresponding terminal receives a radio signal transmitted by the terminal. A method in which terminals transmitting and receiving in an environment in which a plurality of terminals use the same radio frequency use the same resource at the same time may be used. The transmitting terminal may provide resource information to the receiving terminal.

The function of the sidelink in mobile communication may be composed of an interface between the terminal and the terminal and an interface between the terminal and the sidelink server. Here, the side link server may provide information related to side link communication to the terminal. The base station may be included in a communication path between the sidelink server and the terminal, and may mutually transmit packets exchanged between the terminal and the sidelink server. In 3GPP wireless connection, the sidelink may include a PC5 interface between the terminal and the terminal, and may include a PC3 interface between the terminal and the sidelink server.

A terminal, which is the subject of sidelink transmission and reception, may transmit and receive data for searching for a neighboring terminal. The procedure for discovering adjacent terminals may be required prior to setting up a sidelink consisting of a pair of adjacent terminals. The side link server may collect adjacent terminal information and may have adjacent terminal information for a specific terminal.

The transmitting terminal may exchange a request/report message with a side link server that stores terminal discovery information. The side link server may request the transmitting terminal to transmit a discovery message. Accordingly, the transmitting terminal may receive a request for transmission of the discovery message from the side link server. Then, the transmitting terminal may transmit a discovery message to the neighboring terminals. As a result, the neighboring terminal may receive the discovery message and may transmit a discovery response message to the transmitting terminal in response. The transmitting terminal may receive a discovery response message from the adjacent terminal to identify the adjacent terminal. Thereafter, the transmitting terminal may report response information included in the received discovery response message to the side link server. As another discovery method, the transmitting terminal may request the neighbor terminal to transmit a discovery message. Accordingly, the neighboring terminal may receive the request for transmission of the discovery message, and may transmit the discovery message to the transmitting terminal in response. The transmitting terminal may receive a discovery message from the neighboring terminal to identify the counterpart terminal.

The transmitting terminal of the sidelink may transmit control information and data including resource allocation for resources to be used to the receiving terminal. In this case, the base station may allocate resources used by the transmitting terminal. In this case, the transmitting terminal may request resource setting from the base station. Then, the base station may select a resource and allocate it to the transmitting terminal, and may transmit resource allocation information to the transmitting terminal. The transmitting terminal may transmit control information and data information including resource information to the receiving terminal by using the allocated resource. The receiving terminal may check the allocated resource from the received control information, and may receive data using the checked resource. In this way, the transmitting and receiving terminals can exchange data in the sidelink. Alternatively, a resource used by the transmitting terminal by itself may be allocated. As such, the method in which the transmitting terminal selects the resource may be a method in which the transmitting terminal arbitrarily selects a resource used for transmission and reception. After selecting the resource, the transmitting terminal may exchange data with the receiving terminal using the selected resource in the sidelink.

In the sidelink, radio resources may be operated in units of channels according to usage. The physical channel of the sidelink includes a physical sidelink broadcast channel (PSBCH) for transmitting broadcast information to the sidelink, a physical sidelink control channel (PSCCH) for transmitting sidelink control information, a physical sidelink shared channel (PSSCH) for transmitting data, and transmission It may be configured as at least one of a physical sidelink feedback channel (PSFCH) transmitted by the receiving side for the received data. The synchronization signal in the sidelink may include at least one of a sidelink primary synchronization signal (S-PSS), a sidelink secondary synchronization signal (S-SSS), and a channel state information reference signal (CSI-RS) for sidelink channel measurement. .

The receiving terminal, which has received the data transmitted by the transmitting terminal in the sidelink, may inform the transmitting terminal of whether or not it is received. The PSFCH for transmitting whether receiving or not may be shared and used by one terminal or a plurality of terminals. In a one-to-one transmission scheme in which one transmitting terminal and one receiving terminal configure a sidelink, the receiving terminal may use the PSFCH. In a one-to-many transmission scheme in which one transmitting terminal and a plurality of receiving terminals constitute a side link, a plurality of receiving terminals may share the PSFCH. Here, the sharing method may include a method of transmitting on the PSFCH in case of ACK (acknowledgement) and a method of transmitting on the PSFCH in the case of NACK (non-ACK).

A relay terminal (relay UE) may relay data between the network and a remote terminal (remote UE). The relay terminal may access the remote terminal through a sidelink, and may exchange data with the remote terminal by using the sidelink. The relay terminal may access the base station using the Uu interface, and may exchange data with the network using the Uu interface. The remote terminal may exchange data with the network via the relay terminal. The remote terminal may be connected to the sidelink. The remote terminal may be located within the service area of the base station. Alternatively, the remote terminal may be located outside the service area of the base station.

3 is a conceptual diagram illustrating a first embodiment of a method for a relay terminal to relay data.

Referring to FIG. 3 , the first remote terminal 311 may be connected to the network by accessing the first side link 340 . The first relay terminal 310 may be connected to the first side link 340 and may perform a function of relaying data using the first Uu interface 350 . In addition, the second remote terminal 321 may be connected to the network by accessing the second side link 341 . The second relay terminal 320 may be connected to the second side link 341 and perform a function of relaying data using the second Uu interface 351 . The first and second relay terminals 310 and 320 may be located in a service area provided by the base station 330 . Also, the first remote terminal 311 may be located within a service area provided by the base station 330 . Alternatively, the second remote terminal 321 may be located outside the service area.

Receiving system information of relay terminal in Uu link

The relay terminal may receive system information provided by the base station in the service area of the base station. A method for the relay terminal to receive system information through the Uu interface between the base station and the relay terminal may vary depending on the type of system information. When the type of system information is periodic (ie, periodic system information), the base station may periodically broadcast the system information. The relay terminal may receive system information periodically broadcast by the base station. The base station may be divided into groups having different periods of broadcasting system information. In addition, the base station may broadcast system information belonging to the group for each period corresponding to the group. The relay terminal may acquire system information by receiving system information broadcast for each period. The system information broadcast for each period may be determined and periodically broadcast by the base station without a request from the relay terminal.

In contrast, when the type of system information is on-demand (ie, on-demand system information), the base station may transmit the system information to the relay terminal when there is a request from the relay terminal. The relay terminal may request the base station to transmit on-demand system information. In this case, the relay terminal may request the base station to transmit on-demand system information using a sequence or a message. A method of using a sequence may be a method of using a sequence in PRACH. The base station may designate a request sequence that can be used for the purpose of requesting on-demand system information. And, the base station may inform the relay terminal of the designated request sequence. Then, the relay terminal may receive information about the request sequence from the base station,

The relay terminal may transmit a request sequence to the base station for the purpose of requesting on-demand system information. Accordingly, the base station may receive the request sequence from the relay terminal, and may transmit on-demand system information corresponding to the received request sequence to the relay terminal. Accordingly, the relay terminal may receive on-demand system information from the base station. Alternatively, the relay terminal may transmit a message to the base station for the purpose of requesting on-demand system information. Accordingly, the base station may receive a message from the relay terminal and may transmit the on-demand system information requested in the received message to the relay terminal. Accordingly, the relay terminal may receive on-demand system information from the base station.

The base station may transmit the on-demand system information in a broadcast-type transmission method. That is, the base station can broadcast on-demand system information. Then, the relay terminal may receive the on-demand system information broadcast from the base station. In this way, the on-demand system information transmitted in the broadcast transmission method can be utilized not only by the relay terminal but also by all terminals receiving it. Alternatively, the base station may transmit the on-demand system information in a separate transmission method. In the individual transmission method, the base station may identify the relay terminal that has transmitted the request message in the process of receiving the request message requesting transmission of system information. In addition, the base station may transmit the on-demand system information to the corresponding relay terminal in response to the request message. Accordingly, the relay terminal may receive on-demand system information from the base station. As such, when the base station transmits the on-demand system information in the individual transmission method, the destination of the system information may be the relay terminal that has transmitted the request message. In this case, the relay terminal may receive the on-demand system information in the Uu interface in the same way as the general terminal receives the system information. . Meanwhile, the remote terminal may receive system information from the base station by performing the same system information receiving operation performed by the relay terminal in the Uu link.

Request system information from sidelinks

The remote terminal may access the base station via the relay terminal. To this end, the remote terminal may obtain the side link system information configured by the base station and delivered to the relay terminal from the relay terminal. Here, the side link system information may be broadcast type system information. The relay terminal may periodically broadcast sidelink system information on a sidelink broadcast channel (PSBCH).

When the remote terminal is in an area in which a relay terminal receives a signal broadcast, it may periodically receive a sidelink broadcast channel to obtain sidelink system information. The side link system information may include parameters necessary for the remote terminal to access the side link. In addition, the side link system information may include parameters necessary for the remote terminal to access the base station via the relay terminal. Here, parameters necessary for the remote terminal to access the sidelink and parameters for the remote terminal to access the base station via the relay terminal may be referred to as sidelink configuration information.

In this way, the relay terminal can access the remote terminal to the relay terminal through the sidelink, and configure the sidelink configuration information necessary for accessing the base station via the relay terminal as the sidelink system information. And, the relay terminal may periodically broadcast the configured side link system information in the side link. The remote terminal may receive side link system information periodically broadcast by the relay terminal, and may utilize it in a procedure for accessing the relay terminal. In this way, the remote terminal may acquire sidelink system information from the sidelink. Then, the remote terminal may access the base station via the relay terminal using the acquired side link system information.

Here, the side link configuration information may include physical resource information and resource access information related to a side link configuration for enabling the remote terminal to access the side link and transmit a physical signal to the side link. The remote terminal may receive the sidelink system information transmitted from the relay terminal or the base station, and obtain physical resource information and resource access information (ie, sidelink setting information) related to the sidelink configuration from the received site link system information. can Alternatively, the side link configuration information may be configured in advance and stored in the remote terminal.

Meanwhile, the remote terminal may request the relay terminal to transmit on-demand system information. The relay terminal may receive a request for transmission of on-demand system information in the sidelink from the remote terminal. Then, the relay terminal may transmit system information to the remote terminal in response. Accordingly, the remote terminal may receive the on-demand system information from the relay terminal. As such, the on-demand system information may have a characteristic of being transmitted by the relay terminal as a response after the remote terminal initiates the requested procedure. In this case, the remote terminal may request the relay terminal to transmit the on-demand system information by using the request message. The relay terminal may receive a request message requesting transmission of on-demand system information from the remote terminal. Then, the relay terminal may transmit the requested on-demand system information to the remote terminal using the request message.

Meanwhile, the remote terminal may transmit a request notifier to the relay terminal to request the on-demand system information from the relay terminal. The request notifier may be mapped to a signal transmitted to a specific location or specific resource in the sidelink. The resource to which the request notifier is transmitted may be repeated periodically. Alternatively, the resource to which the request notifier is transmitted may be configured in a periodically repeated pattern. Such a request notifier may be notified by the relay terminal to the remote terminal through side link configuration information. In this way, the remote terminal may obtain the request notifier information from the side link configuration information obtained from the relay terminal. The remote terminal may transmit a request notifier to the relay terminal at a time when it is determined to request the on-demand system information. The relay terminal may receive the request notifier from the remote terminal, and thus may confirm the request for transmission of the on-demand system information. The request notifier may be configured identically to a plurality of remote terminals due to a feature that is mapped to a location or resource. That is, a plurality of remote terminals may transmit the request notifier at the same time. Accordingly, the relay terminal may receive the request notifiers and transmit the on-demand system information on the sidelink in a broadcast manner. As such, the relay terminal may transmit system information to a plurality of remote terminals in a broadcast-type transmission method.

Meanwhile, the remote terminal may transmit a discovery message including a request notifier to the relay terminal in order to request the on-demand system information from the relay terminal. A relay terminal and a remote terminal capable of accessing the sidelink may exchange discovery messages with each other for the purpose of discovering each other. The relay terminal or the remote terminal may transmit a discovery message in the configured resource. When the relay terminal or the remote terminal receives the discovery message, it may transmit a discovery response message in response thereto. In this case, the discovery message and the discovery response message may be identical to each other. Alternatively, the discovery message and the discovery response message may be configured as a request/response pair. The relay terminal or the remote terminal may transmit the discovery message including the request notifier. In particular, the remote terminal may transmit a discovery message including the request notifier to the relay terminal. Then, the relay terminal may receive the discovery message including the request notifier to confirm the request for transmission of the on-demand system information from the remote terminal. Accordingly, the relay terminal may transmit the on-demand system information according to the request notifier in the discovery response message to the remote terminal. The remote terminal may obtain the on-demand system information included in the discovery response message by receiving the discovery response message.

Meanwhile, the remote terminal may configure a logical channel through which the discovery message is transmitted differently to request the on-demand system information from the relay terminal. The remote terminal may configure a logical channel for transmitting a discovery message including a system information request differently from a logical channel for transmitting a general discovery message.

As such, a logical channel configured differently from a logical channel for transmitting a general discovery message by the remote terminal may be referred to as a request logical channel. Accordingly, the remote terminal may transmit a discovery message requesting the on-demand system information to the relay terminal to the relay terminal through the request logical channel. Here, the request logical channel may be distinguished from a logical channel for transmitting a general discovery message used when there is no request. To this end, the remote terminal may construct a discovery message including a MAC protocol data unit (PDU) including the requested logical channel identifier. In addition, the remote terminal may transmit a discovery message to the relay terminal from the resource of the sidelink. The relay terminal may receive the discovery message in the sidelink and may obtain a logical channel identifier from the MAC PDU included in the received discovery message. Accordingly, the relay terminal can confirm that it is the requested logical channel and can confirm the request for transmission of the on-demand system information. Accordingly, the relay terminal may transmit the on-demand system information to the remote terminal by including the on-demand system information in the discovery response message. The remote terminal may obtain the on-demand system information included in the discovery response message by receiving the discovery response message.

On the other hand, the remote terminal may differently configure the transmission resource through which the discovery message is transmitted in order to request the on-demand system information from the relay terminal. As such, the remote terminal may configure the sidelink resource for transmitting the discovery message differently from the sidelink resource for transmitting the general discovery message. As such, the sidelink resource for transmitting the discovery message can be divided into a general discovery resource through which a general discovery message is transmitted and a requested discovery resource through which a discovery message requesting system information is transmitted. In addition, the relay terminal and the remote terminal may share identification information for distinguishing between a normal discovery resource and a requested discovery resource. The remote terminal may transmit a discovery message to the relay terminal using the requested discovery resource in order to request the on-demand system information from the relay terminal. The relay terminal may receive a discovery message from the requested discovery resource. In addition, the relay terminal may confirm a request for transmission of on-demand system information from the remote terminal as a discovery message is received from the request discovery resource. Accordingly, the relay terminal may transmit the on-demand system information to the remote terminal by including the on-demand system information in the discovery response message. The remote terminal may obtain the on-demand system information included in the discovery response message by receiving the discovery response message.

Meanwhile, the remote terminal may configure a request message to request the on-demand system information from the relay terminal. The remote terminal may transmit the configured request message to the relay terminal by sharing the resource through which the discovery message is transmitted. A request message transmitted by sharing the resource through which the discovery message is transmitted can be distinguished from the discovery message by differentiating the message identifier. That is, the message identifier included in the request message may be different from the message identifier included in the discovery message. The remote terminal may transmit a request message including a message identifier different from the message identifier of the discovery message to the relay terminal using a resource for transmitting the discovery message. Accordingly, the relay terminal may receive the request message through the resource through which the discovery message is transmitted. In addition, it can be confirmed that the request message is a request message through the message identifier included in the received request message. Accordingly, the relay terminal may confirm the request for transmission of the on-demand system information from the remote terminal. Accordingly, the relay terminal may transmit the on-demand system information to the remote terminal by including the on-demand system information in the discovery response message. The remote terminal may obtain the on-demand system information included in the discovery response message by receiving the discovery response message. Additionally, the remote terminal may transmit the request message to the relay terminal by using the logical channel distinguished by distinguishing the logical channel through which the request message is transmitted from the logical channel through which the discovery message is transmitted.

Also, of course, the remote terminal may transmit the configured request message to the relay terminal using a separate resource without sharing the resource through which the discovery message is transmitted. Accordingly, the relay terminal may receive the request message through a resource separate from the resource through which the discovery message is transmitted. Then, the relay terminal may check the request for transmission of the on-demand system information from the remote terminal. Accordingly, the relay terminal may transmit the on-demand system information to the remote terminal through a response message different from the discovery response message. Of course, the relay terminal may transmit the on-demand system information to the remote terminal by including the on-demand system information in the discovery response message.

On-Demand System Information Procedures

The remote terminal and the relay terminal may acquire system information through a signaling procedure in the sidelink. In addition, the remote terminal and the relay terminal may perform a subsequent sidelink connection establishment procedure by using the system information obtained from the sidelink. That is, in the case of broadcast type system information, the relay terminal may periodically broadcast the system information. In addition, the remote terminal may acquire broadcast system information and proceed with a side link connection establishment procedure. Alternatively, in the case of on-demand system information, the remote terminal may request transmission of the system information to the relay terminal. Accordingly, the relay terminal may receive a request for transmission of system information from the remote terminal. Then, the relay terminal may transmit system information to the remote terminal in response thereto. Meanwhile, each of the remote terminal and the relay terminal may perform a subsequent sidelink connection establishment procedure using the stored system information.

The remote terminal may move to a communication service area of another relay terminal in the RRC idle state. Alternatively, the remote terminal may move to a communication service area of another base station in an RRC idle state. In this case, the remote terminal may attempt sidelink access to access a new relay terminal or a new base station. The remote terminal may request system information from the relay terminal or the base station for sidelink access. The relay terminal may receive a request for transmission of system information from the remote terminal. And, in response to this, the relay terminal may transmit on-demand system information to the remote terminal.

The relay terminal may transmit the on-demand system information to the remote terminal in a broadcast transmission method or an individual transmission method. In the broadcast transmission method, the relay terminal may transmit system information to the remote terminal by using a broadcast identifier that can be received by a plurality of terminals including the remote terminal. In the individual transmission method, the relay terminal may transmit system information to the corresponding remote terminal by using the identifier of the remote terminal. Accordingly, the remote terminal may receive system information. In addition, the remote terminal may access the sidelink based on the received system information and proceed with the setup procedure.

Meanwhile, the remote terminal may request transmission of system information to the relay terminal in order to acquire system information that has not been obtained in the RRC connected state. In this case, the remote terminal may request transmission of the system information to the relay terminal by transmitting an RRC message including the request information to the relay terminal. Accordingly, the relay terminal may receive the RRC message including the request information of the system information from the remote terminal. In addition, the relay terminal may transmit an RRC message including system information to the remote terminal in response. Accordingly, the remote terminal may receive the RRC message including the system information, and may obtain the system information included in the received RRC message.

navigation procedure

The remote terminal may transmit the request information to the relay terminal in conjunction with the discovery procedure. The remote terminal and the relay terminal may enable system information request information to be included in a discovery message used in a discovery procedure for mutual discovery. In this case, the request information may be included in the discovery message and transmitted from the remote terminal to the relay terminal. Alternatively, the request information may be transmitted from the remote terminal to the relay terminal using a logical channel separated from a logical channel through which a general discovery message is transmitted using the request logical channel identifier. Alternatively, the request information may be transmitted from the remote terminal to the relay terminal through a request transmission resource different from the transmission resource through which the general discovery message is transmitted.

Meanwhile, the relay terminal may receive a request for transmission of system information from the remote terminal in the discovery procedure. Then, the relay terminal may transmit the on-demand system information to the remote terminal in response. In the discovery procedure, the remote terminal may transmit the identifier of the remote terminal to the relay terminal. Accordingly, the relay terminal may receive the identifier of the remote terminal transmitted from the remote terminal, and may identify the remote terminal through the received identifier of the remote terminal.

4A is a flowchart illustrating a first embodiment of a method for obtaining system information of a remote terminal.

Referring to FIG. 4A , in the method of obtaining system information of a remote terminal, the remote terminal may transmit a request message including request information for requesting system information to the relay terminal (S401a). Accordingly, the relay terminal may receive a request message including request information from the remote terminal. Then, the relay terminal may transmit the on-demand system information to the remote terminal in response (S402a). The remote terminal may receive on-demand system information. Thereafter, the remote terminal and the relay terminal may proceed with a setting procedure of exchanging control messages based on system information (S403a).

4B is a flowchart illustrating a second embodiment of a method for obtaining system information of a remote terminal.

Referring to FIG. 4B , in the method of obtaining system information of a remote terminal, the remote terminal may transmit a discovery message including request information for requesting system information to the relay terminal (S401b). Accordingly, the relay terminal may receive a discovery message including request information from the remote terminal. Then, the relay terminal may transmit the on-demand system information to the remote terminal in response (S402b). The remote terminal may receive on-demand system information. Thereafter, the remote terminal and the relay terminal may proceed with a setup procedure of exchanging control messages based on system information (S403b).

Request system information for relay

The base station may provide the managed radio resource for use by the relay terminal and the remote terminal associated with or mapped to the relay terminal. In addition, the base station may provide the relay terminal and the remote terminal with system information (ie, parameters) necessary for using the radio resource managed by the relay terminal and the remote terminal. In particular, the base station may provide the relay terminal and the remote terminal with system information necessary for the communication operation of the side link between the relay terminal and the remote terminal. The base station may provide relay system information for a side link that periodically performs a relay operation to the relay terminal. Alternatively, the base station may provide relay system information for a sidelink performing a relay operation to the relay terminal when there is a request from the relay terminal. Accordingly, the relay terminal may receive relay system information required in the operation of relaying the remote terminal from the base station.

Here, the relay terminal may use a physical random access channel (PRACH) as a method of requesting relay system information from the base station. The base station may designate a specific sequence (ie, a specific sequence for relay) from sequences used in the PRACH to be used for requesting relay system information. In this case, the base station may designate a specific sequence of the PRACH used to request the relay system information not to overlap with the PRACH sequences used in the Uu interface.

The base station may designate a specific sequence for relaying of the PRACH used to request the system information for relay to be different from the specific sequence of the PRACH used for requesting the on-demand system information used in the Uu interface. The relay terminal may transmit a specific sequence for requesting relay system information to the base station in the PRACH at the time of requesting the relay system information. Accordingly, the base station may receive a specific sequence for relay requesting relay system information, and may transmit relay system information to the relay terminal in response thereto. Accordingly, the relay terminal may receive relay system information from the base station.

Meanwhile, the relay terminal may use the control message as a method of requesting relay system information from the base station. That is, the relay terminal may transmit a control message requesting relay system information to the base station. The base station may receive a control message requesting transmission of system information for relay from the relay terminal. In addition, the base station may transmit relay system information to the relay terminal in response thereto. Accordingly, the relay terminal may receive relay system information from the base station.

In this case, the control message transmitted from the relay terminal to the base station may include a message identifier that enables the base station to identify that it is a message requesting relay system information. Accordingly, the relay terminal may transmit a control message including a message identifier for requesting relay system information to the base station. The base station may receive a control message including a message identifier for requesting transmission of system information for relay from the relay terminal. In addition, the base station may recognize the request for relay system information through the message identifier, and may transmit the relay system information to the relay terminal in response thereto. Accordingly, the relay terminal may receive relay system information from the base station.

On-demand system information delivery procedure

The relay terminal may be located between the base station and the remote terminal. In this case, the relay terminal may access the base station using the Uu interface. In addition, the relay terminal may access the remote terminal using a side link interface. In such a structure, the relay terminal may receive request information of on-demand system information for the base station from the remote terminal and transmit it to the base station. In addition, the relay terminal may receive the on-demand system information for the remote terminal from the base station and transmit it to the remote terminal.

When the remote terminal needs to receive the on-demand system information from the base station, it may transmit request information of the on-demand system information for the base station to the relay terminal. Then, the relay terminal may receive the request information of the on-demand system information for the base station from the remote terminal. Thereafter, the relay terminal may transmit the request information of the on-demand system information for the base station to the base station. Accordingly, the base station may receive the request information of the on-demand system information from the relay terminal. In response, the base station may transmit on-demand system information for the remote terminal to the relay terminal. The relay terminal may receive on-demand system information for the remote terminal from the base station. Then, the relay terminal may transmit the received on-demand system information about the remote terminal to the remote terminal. The remote terminal may receive on-demand system information from the relay terminal. In this way, the relay terminal may perform a relay delivery function of request information of on-demand system information and system information. In addition, the relay terminal may not store the request information or the on-demand system information after the relay procedure is completed.

Here, the request information of the on-demand system information and the transmission of the system information may be performed through control messages defined in the Uu interface and the PC5 side link interface, respectively. That is, when the remote terminal needs to receive the on-demand system information from the base station, it may transmit the request information of the on-demand system information for the base station to the relay terminal using the control message of the PC5 interface. Then, the relay terminal may receive the request information of the on-demand system information for the base station from the remote terminal. Thereafter, the relay terminal may transmit request information of on-demand system information for the base station to the base station using a control message of the Uu interface. Accordingly, the base station may receive the request information of the on-demand system information from the relay terminal. In response, the base station may transmit on-demand system information for the remote terminal to the relay terminal using a control message of the Uu interface. The relay terminal may receive on-demand system information for the remote terminal from the base station. In addition, the relay terminal may transmit the received on-demand system information about the remote terminal to the remote terminal using a control message of the PC5 interface. The remote terminal may receive on-demand system information from the relay terminal.

In this way, the relay terminal may receive a control message requesting transmission of system information to the base station through the PC5 interface from the remote terminal. In this case, the relay terminal may convert a control message requesting transmission of system information received from the remote terminal through the PC5 interface into a control message requesting transmission of system information through the Uu interface, and transmit it to the base station. Additionally, the relay terminal may receive a control message requesting transmission of system information from the remote terminal through the PC5 interface. In this case, the relay terminal may transmit a control message requesting transmission of the system information received through the PC5 interface to the base station through the Uu interface. And, similarly, the relay terminal may receive a control message including system information from the base station through the Uu interface. In this case, the relay terminal may convert the control message including the system information received through the Uu interface into a control message including the system information in the PC5 interface and transmit it to the remote terminal. Additionally, the relay terminal may receive a control message including system information from the base station through the Uu interface. In this case, the relay terminal may transmit the control message including the system information received through the Uu interface to the remote terminal through the PC5 interface.

Alternatively, the relay terminal may operate in a manner of transferring data in the Uu interface and the PC5 side link interface. In this case, the relay terminal may exchange control messages through the RRC protocol located in the base station associated with or mapped to the Uu interface and the RRC protocol located in the remote terminal associated with or mapped to the PC5 side link interface.

That is, when the remote terminal needs to receive the on-demand system information from the base station, it may configure the request information of the on-demand system information for the base station as a control message. And, the remote terminal may configure data including the configured control message. The remote terminal may transmit data including the configured control message to the relay terminal. In this case, the relay terminal may receive data including the control message. In addition, the relay terminal may transmit data including the received control message to the base station. Accordingly, the base station may receive data including the control message from the relay terminal. And, the base station may obtain the control message from the data including the received control message. The base station may check the request for transmission of the on-demand system information of the remote terminal through the acquired control message.

Meanwhile, the base station may configure a control message including the on-demand system information according to the request for transmission of the on-demand system information of the remote terminal. The base station may configure data including control messages. The base station may transmit data including the control message to the relay terminal. In this case, the relay terminal may receive data including the control message. In addition, the relay terminal may transmit data including the received control message to the remote terminal. Accordingly, the remote terminal may receive data including the control message from the relay terminal. Then, the remote terminal may obtain the control message from the data including the received control message. The base station may check the on-demand system information transmitted by the base station through the acquired control message. As such, a control message requesting system information and a control message including system information may be exchanged between the remote terminal and the base station, and the relay terminal may operate in a manner that relays data corresponding to the control message.

5 is a flowchart illustrating a first embodiment of a method for a relay terminal to relay on-demand system information.

Referring to FIG. 5 , when it is necessary to receive on-demand system information from the base station, the remote terminal may transmit request information of on-demand system information for the base station to the relay terminal (S501). Then, the relay terminal may receive the request information of the on-demand system information for the base station from the remote terminal. Thereafter, the relay terminal may transmit the request information of the on-demand system information for the base station to the base station (S502). Accordingly, the base station may receive the request information of the on-demand system information from the relay terminal. In response, the base station may transmit on-demand system information for the remote terminal to the relay terminal (S503). The relay terminal may receive on-demand system information for the remote terminal from the base station. Then, the relay terminal may transmit the received on-demand system information about the remote terminal to the remote terminal (S504). The remote terminal may receive on-demand system information from the relay terminal. Thereafter, the remote terminal and the relay terminal may proceed with a setup procedure of exchanging control messages based on system information (S505).

In this way, the relay terminal can relay the request information of the on-demand system information transmitted from the remote terminal to the base station, and can relay the on-demand system information transmitted from the base station to the remote terminal.

Side link system information transmission

The relay terminal may transmit the system information to the remote terminal by including the system information in the broadcast type control message. The relay terminal may configure a broadcast-type control message including system information and broadcast the broadcast-type control message in the PC5 sidelink section. In this case, the relay terminal may periodically broadcast a broadcast-type control message. Alternatively, the relay terminal may broadcast the broadcast-type control message when there is a request for system information of the remote terminal. Accordingly, the remote terminal may receive a broadcast type control message including system information broadcast from the relay terminal. Then, the remote terminal may acquire system information from the received broadcast type control message.

Alternatively, the relay terminal may transmit the system information to the remote terminal in an individual transmission control message. The relay terminal may configure the individual transmission control message including system information, and may transmit the individual transmission control message to the remote terminal in the PC5 sidelink section. As an example, the relay terminal may configure the individual transmission control message as an RRC control message. In this case, the relay terminal may periodically transmit an individual transmission control message. Alternatively, the relay terminal may transmit an individual transmission control message when there is a request for system information of the remote terminal. Accordingly, the remote terminal may receive the individual transmission control message including the system information transmitted from the relay terminal. Then, the remote terminal may obtain system information from the received individual transmission control message.

In this way, the relay terminal may receive the system information request from the remote terminal and transmit it to the base station. And, the relay terminal may receive system information from the base station. The relay terminal may transmit the system information received from the base station to the remote terminal as a broadcast control message or an individual transmission control message. A procedure in which the relay terminal requests and obtains system information from the base station may occur independently of the system request procedure between the remote terminal and the relay terminal. That is, if the relay terminal has already acquired the requested system information, the relay terminal can immediately transmit the already acquired system information to the remote terminal. In this case, if the relay terminal does not have the system information requested by the remote terminal, it may request the base station to obtain system information from the base station and transmit it to the remote terminal.

On-demand system information management led by relay terminals

The relay terminal may proactively manage the on-demand system information in the sidelink. The relay terminal may request the base station to transmit on-demand system information. In addition, when there is a request for transmission of on-demand system information from the remote terminal later, the relay terminal may provide the on-demand system information already received and stored by the base station to the remote terminal.

Meanwhile, the base station may change the on-demand system information. In this case, the base station may designate and manage a version for each system information so that the changed system information can be distinguished from the previous system information. As such, when the system information is changed, the base station may transmit the changed version of the system information to the relay terminal. In this case, the base station may transmit the changed version of the system information to the relay terminal in a broadcast transmission method or an individual transmission method.

The relay terminal may receive the changed version of the system information from the base station and may check whether the received version of the system information is the same as the version of the latest stored system information. If the version of the received system information is the same as the version of the latest stored system information, the relay terminal may continue to use the stored system information. Alternatively, if the version of the received system information is different from the version of the stored system information, the relay terminal may proceed with a procedure for requesting the changed on-demand system information. Accordingly, the base station may transmit the changed on-demand system information to the relay terminal in response. Upon receiving this, the relay terminal may transmit the changed on-demand system information to the remote terminal in response to the request of the remote terminal in the side link interface. The relay terminal can continue to use by storing the changed on-demand system information received from the base station.

6 is a flowchart illustrating a second embodiment of a method for a relay terminal to relay on-demand system information.

Referring to FIG. 6 , when on-demand system information is required, the relay terminal may transmit request information of on-demand system information to the base station (S601). Accordingly, the base station may receive the request information of the on-demand system information from the relay terminal. Then, the base station may transmit the on-demand system information to the relay terminal in response thereto (S602). The relay terminal may receive on-demand system information from the base station.

Thereafter, when it is necessary to receive the on-demand system information from the base station, the remote terminal may transmit the request information of the on-demand system information to the relay terminal (S603). Then, the relay terminal may receive the request information of the on-demand system information from the remote terminal. In this case, the relay terminal may determine whether the on-demand system information received and stored by the base station corresponds to the on-demand system information requested by the remote terminal. The relay terminal may transmit the on-demand system information to the remote terminal if they match as a result of the determination (S604). The remote terminal may receive on-demand system information from the relay terminal. Thereafter, thereafter, the remote terminal and the relay terminal may perform a setting procedure of exchanging control messages based on system information ( S605 ).

As such, the relay terminal may receive and store the on-demand system information transmitted from the base station. In addition, when the relay terminal requests on-demand system information stored by the remote terminal, the relay terminal may transmit the on-demand system information to the remote terminal in response.

Control of system information relay function of relay terminal led by remote terminal

The remote terminal may be located in the service area of the base station. In this case, the remote terminal may directly receive system information provided by the base station from the base station through the Uu interface. In this way, when the remote terminal receives the system information from the base station, it may not receive the system information transmitted by the relay terminal. In this case, the remote terminal may notify the relay terminal that relaying of system information is unnecessary.

This may be achieved by the remote terminal sending the relay stop request to the relay terminal by including the relay function control message in the relay function control message. That is, the remote terminal may transmit a relay function control message including a relay stop request to the relay terminal. Then, the relay terminal may receive the relay function control message including the relay stop request from the remote terminal. In addition, the relay terminal may recognize that relaying of the system information transmitted from the base station to the corresponding remote terminal is unnecessary through the relay stop request included in the relay function control message. Accordingly, the relay terminal may no longer relay the system information transmitted from the base station to the remote terminal. Meanwhile, when a relay terminal transmits system information to remote terminals in a broadcast transmission method, all connected remote terminals may stop relaying system information when there is a request to stop relaying the system information.

Alternatively, the remote terminal may configure the relay stop request in the form of a relay function control field, include it in a control message different from the relay function control message, and transmit it to the relay terminal. That is, the remote terminal may transmit a control message including the relay function control field of the relay stop request to the relay terminal. Then, the relay terminal may receive a control message including the relay function control field of the relay stop request from the remote terminal. In addition, the relay terminal may recognize that the relay function for the corresponding remote terminal is unnecessary through the relay function control field of the relay stop request included in the received control message. Accordingly, the relay terminal may no longer relay the system information transmitted from the base station to the remote terminal. Meanwhile, when the relay terminal transmits system information to the remote terminals in the broadcast transmission method, all connected remote terminals may stop relaying the system information when there is a request to stop relaying the system information.

Meanwhile, while the remote terminal is located in the service area of the base station and receives system information from the base station, direct reception of system information from the base station may be stopped. In this case, the remote terminal may need to receive system information from the relay terminal again. Of course, when the remote terminal leaves the service area of the base station, it may be necessary to receive system information from the relay terminal again.

In this case, the remote terminal may inform the relay terminal that it is necessary to receive system information. That is, the remote terminal may inform the relay terminal that it is not receiving system information transmitted from the base station through the Uu interface. This may be achieved by the remote terminal composing a relay initiation request as a relay function control message and transmitting it to the relay terminal. That is, the remote terminal may transmit a relay function control message including a relay initiation request to the relay terminal. Then, the relay terminal may receive the relay function control message including the relay initiation request from the remote terminal. In addition, the relay terminal may recognize the necessity of starting the relay function for the corresponding remote terminal through the received relay function control message. Accordingly, the relay terminal may start transmitting system information back to the remote terminal. Then, the remote terminal may receive the system information from the relay terminal.

Alternatively, the remote terminal may configure the relay initiation request in the form of a relay function control field, include it in another control message, and transmit it to the relay terminal. That is, the remote terminal may transmit a control message including the relay function control field of the relay initiation request to the relay terminal. Then, the relay terminal may receive a control message including the relay function control field of the relay initiation request from the remote terminal. In addition, the relay terminal may recognize the need for a relay function for the corresponding remote terminal through the received control message. In this case, the relay terminal may transmit system information to the remote terminals. Meanwhile, when the relay terminal transmits system information to remote terminals in a broadcast-type transmission method, when at least one remote terminal changes to a state requiring reception of system information, relay of the system information may be started.

Receiving paging information from the relay terminal on the Uu link

The base station may perform paging by transmitting a paging message to the relay terminal when the relay terminal is in the RRC idle state. Accordingly, the relay terminal may receive the paging message. Thereafter, the relay terminal may perform an RRC connection establishment procedure in response to access the network and exchange data with the base station. Meanwhile, the base station may perform paging by transmitting a paging message to the relay terminal when the relay terminal is in an RRC inactive state. Accordingly, the relay terminal may receive the paging message. Thereafter, the relay terminal may exchange data by changing to the RRC connection state by performing an RRC connection establishment procedure in response. Such an operation may be applied to a configuration in which a relay terminal becomes an endpoint of a connection.

Meanwhile, the base station may provide the relay terminal with an identifier used for the paging procedure of the relay terminal in the RRC connected state before the relay terminal enters the RRC idle state or the RRC deactivation state. The base station may provide the relay terminal identifier A used for paging the relay terminal in the RRC idle state to the relay terminal. In addition, the base station may provide the relay terminal identifier B, which is used for paging the relay terminal in the RRC deactivation state through a radio access network (RAN) paging procedure, to the relay terminal. Here, the relay terminal identifier A may have the form of, for example, a new generation 5G standalone temporary mobile subscriber identity (NG-5G-S-TMSI), and the relay terminal identifier B may have the form of, for example, an inactive RNTI (I-RNTI). can have Accordingly, the relay terminal may receive the relay terminal identifier A and the relay terminal identifier B from the base station, and is repeated at a predetermined period (discontinuous reception (DRX) Cycle) using the received relay terminal identifier A and the relay terminal identifier B. It may be associated or mapped to a paging occasion (PO). Here, the predetermined period may consist of a plurality of paging occasions. The base station may transmit a paging message to the relay terminal in a paging operation associated with or mapped to the relay terminal identifier provided to the relay terminal at the time of paging the relay terminal. Accordingly, the relay terminal may determine the paging error associated with or mapped to the relay terminal identifier used for paging. Then, the relay terminal may receive the paging message in the corresponding paging operation. Meanwhile, the remote terminal may perform the same paging reception operation performed by the relay terminal in the Uu link.

Paging the remote terminal on the sidelink

The remote terminal may access the base station through a side link provided by the relay terminal. In this case, the remote terminal may not directly receive the paging message provided by the base station. The remote terminal may move to a new area where the current base station cannot provide communication services. Then, the remote terminal may proceed with a procedure of registering with a new base station that provides a communication service in a new area. In addition, the remote terminal may move out of an area in which the relay terminal provides a communication service. In this way, the remote terminal may move to a new area where the current relay terminal cannot provide a communication service. Then, the remote terminal may perform a discovery procedure with a new relay terminal capable of providing a communication service in a new area. In this case, the new relay terminal may transmit the relay terminal identifier to the remote terminal while performing a discovery procedure with the remote terminal. Accordingly, the remote terminal may acquire the relay terminal identifier of the new relay terminal. Similarly, the remote terminal may deliver the remote terminal identifier to the new relay terminal while proceeding with the discovery procedure. Accordingly, the new relay terminal may acquire the remote terminal identifier of the remote terminal.

Meanwhile, the remote terminal may be connected to the relay terminal through a sidelink in RRC idle or RRC inactive state. The base station may send a paging message to page the remote terminal. In this case, when the remote terminal is located outside the communication service area of the base station, the paging message provided by the Uu interface cannot be received. As a solution to this problem, the relay terminal may receive a paging message transmitted to the remote terminal from the base station. Then, the relay terminal may check whether the remote terminal is paging from the received paging message. When paging of the remote terminal is confirmed in the received paging message, the relay terminal may deliver the paging message to the remote terminal. Then, the relay terminal may activate a side link with the paged remote terminal. Meanwhile, the remote terminal may receive a paging message from the relay terminal. Then, the remote terminal may transmit a response message to the paging message to the relay terminal. The relay terminal may receive the response message of the remote terminal and transmit it to the base station. Accordingly, the base station may receive a response message from the relay terminal.

On the other hand, the RRC idle or RRC inactive relay terminal is associated with or mapped paging error (PO) associated with the relay terminal identifier and the remote terminal identifier in order to receive a paging message transmitted to the remote terminal. PO) may receive a paging message. The relay terminal may receive a paging message in each paging operation. Then, the relay terminal may check the terminal identifier to be paged in the received paging message. The relay terminal may proceed with the RRC setup procedure or activation procedure in response if the checked terminal identifier is the relay terminal identifier. Alternatively, in the relay terminal, the confirmed terminal identifier may be a remote terminal identifier, and if the sidelink is in an inactive state, the relay terminal may activate the sidelink. And, the relay terminal may deliver the paging message to the remote terminal. Accordingly, the remote terminal may receive the paging message from the relay terminal. Then, the remote terminal may transmit a response message to the paging message to the relay terminal. The relay terminal may receive the response message of the remote terminal and transmit it to the base station. Accordingly, the base station may receive a response message from the relay terminal.

Here, the paging message transmitted by the relay terminal to the remote terminal through the side link may be the same as the paging message received by the relay terminal from the base station. Alternatively, the paging message transmitted by the relay terminal to the remote terminal through the sidelink may be a paging message reconfigured for the purpose of transferring the paging message received by the relay terminal from the base station to the remote terminal through the sidelink. In this case, the terminal identifier included in the paging message received by the relay terminal may be the remote terminal identifier, and if the side link is in an inactive state, the relay terminal may include the paging information in a message for activating the side link and transmit it to the remote terminal. Accordingly, the remote terminal may receive a message including paging information from the relay terminal. In addition, the remote terminal may transmit a response message to the message including the paging information to the relay terminal. The relay terminal may receive the response message of the remote terminal and transmit it to the base station. Accordingly, the base station may receive a response message from the relay terminal.

7 is a flowchart illustrating a first embodiment of a method for relaying a paging message by a relay terminal.

Referring to FIG. 7 , the base station may transmit a paging message including remote terminal identifier information to the relay terminal in order to page the remote terminal. Then, the relay terminal may receive a paging message from the base station (S701). Then, the relay terminal can confirm that the paging message is destined for the remote terminal through the remote terminal identifier in the received paging message. Accordingly, the relay terminal may activate a side link with the remote terminal (S702). Then, the relay terminal may transmit a paging message to the remote terminal through the side link (S703). Meanwhile, the remote terminal may receive a paging message from the relay terminal. Then, the remote terminal may transmit a response message to the paging message to the relay terminal. The relay terminal may receive the response message of the remote terminal and transmit it to the base station. Accordingly, the base station may receive a response message from the relay terminal.

Here, the relay terminal may transmit the same paging message as the paging message received from the base station through the sidelink to the remote terminal. Alternatively, the relay terminal may obtain the remote terminal identifier from the paging message received from the base station through the sidelink to the remote terminal, construct a newly constructed separate paging message, and transmit it to the remote terminal.

8 is a flowchart illustrating a second embodiment of a method for relaying a paging message by a relay terminal.

Referring to FIG. 8 , the base station may transmit a paging message including remote terminal identifier information to the relay terminal in order to page the remote terminal (S801). Then, the relay terminal may receive the paging message including the remote terminal identifier from the base station. Then, the relay terminal can confirm that the paging message is destined for the remote terminal through the remote terminal identifier in the received paging message. Accordingly, the relay terminal may activate a sidelink with the remote terminal, and may transmit an activation request message including paging information to the remote terminal in order to transmit the paging information (S802). Here, the paging information may be a remote terminal identifier in the paging message.

Meanwhile, the remote terminal may receive an activation request message including paging information from the relay terminal. Then, the remote terminal may proceed with activation in response to the activation request message, and may transmit an activation response message to the relay terminal (S803). The relay terminal may receive an activation response message from the remote terminal.

Here, the remote terminal may provide the remote terminal identifier information to the relay terminal. The relay terminal may receive remote terminal identifier information from the remote terminal. As such, the remote terminal may provide the remote terminal identifier to the relay terminal in the sidelink activated after the sidelink discovery procedure. Meanwhile, the relay terminal may request remote terminal identifier information from the base station. The base station may receive a request for transmission of remote terminal identifier information from the relay terminal. And, the base station may transmit the remote terminal identifier to the relay terminal in the Uu interface. Then, the relay terminal may receive the remote terminal identifier information from the base station. Accordingly, the relay terminal may check the remote terminal identifier in order to check information on the paging error of the remote terminal.

9 is a flowchart illustrating a first embodiment of a method for a relay terminal to obtain a terminal identifier.

Referring to FIG. 9 , in the method for the relay terminal to obtain the terminal identifier, the base station may transmit the relay terminal identifier to the relay terminal so that the relay terminal receives the paging message ( S901 ). Then, the relay terminal may receive the relay terminal identifier from the base station.

Meanwhile, the remote terminal may proceed with the discovery procedure (S902), and may transmit the remote terminal identifier to the newly discovered relay terminal through the sidelink (S903). Here, the remote terminal may configure and transmit the remote terminal identifier as a message different from the message used in the discovery procedure. Alternatively, the remote terminal may include the remote terminal identifier in a field of a message used in the discovery procedure and transmit it to the relay terminal. Meanwhile, the remote terminal may request relay delivery of the paging message to the relay terminal.

10 is a flowchart illustrating a second embodiment of a method for a relay terminal to obtain a terminal identifier.

Referring to FIG. 10 , in the method for the relay terminal to obtain the terminal identifier, the base station may transmit the relay terminal identifier to the relay terminal so that the relay terminal receives the paging message (S1001). Then, the relay terminal may receive the relay terminal identifier from the base station.

Meanwhile, the remote terminal may proceed with the discovery procedure ( S1002 ), and may access the newly discovered relay terminal through a side link. As such, when a new remote terminal accesses, the relay terminal may request transmission of the remote terminal identifier from the newly accessed remote terminal to the base station (S1003). Then, the base station may receive a transmission request for the remote terminal identifier from the relay terminal. Then, the base station may transmit the remote terminal identifier to the relay terminal so that the relay terminal receives the paging message for the remote terminal (S1004). Then, the relay terminal may receive the remote terminal identifier from the base station. Accordingly, the relay terminal may receive the paging message transmitted from the base station to the remote terminal from the base station in the paging operation of the remote terminal in the Uu interface.

Power saving of relay terminal

As the number of remote terminals managed by the relay terminal increases, the number of paging errors to be performed in order to receive a paging message from the base station may increase. As such, as the paging error increases, the relay terminal may perform a receiving operation more frequently. As such, when the relay terminal frequently performs the reception operation, the advantage of the RRC idle or DRX operation in the RRC inactive state may be reduced to reduce power consumption. Therefore, in order to improve this, the communication system may need to reduce the paging error in which the relay terminal must perform a reception operation in order to receive the paging message from the base station.

Meanwhile, the base station may transmit a paging message to the relay terminal in order to page the relay terminal in the Uu interface. In this case, the base station may transmit the paging message to the relay terminal in a paging error associated with or mapped to the relay terminal identifier. In addition, when the base station transmits a paging message for paging the remote terminal to the relay terminal in the Uu interface, the base station may transmit the paging message to the relay terminal in a paging error associated with or mapped to the remote terminal identifier. Accordingly, the relay terminal may receive a paging message in a paging error associated with or mapped to the relay terminal identifier and a paging error associated with or mapped to the remote terminal identifier. Accordingly, the operation of the relay terminal receiving the paging message may be increased.

To solve this, the base station may transmit a paging message including the remote terminal identifier for paging the remote terminal in the Uu interface to the relay terminal in a paging operation associated with or mapped to the relay terminal identifier. Then, the relay terminal may receive the paging message from the base station in a paging error associated with or mapped to the relay terminal identifier. The relay terminal can confirm that the paging message is destined for the remote terminal through the remote terminal identifier in the received paging message. Accordingly, the relay terminal may activate a side link with the remote terminal. In addition, the relay terminal may transmit a paging message to the remote terminal through the sidelink. As such, the paging error of the relay terminal may be determined by the relay terminal identifier irrespective of the remote terminal identifier. Accordingly, the number of paging errors in which the relay terminal needs to receive a paging message from the base station can be reduced.

Meanwhile, the base station may provide the relay terminal with a paging identifier for relay in order to designate a paging operation in which the relay terminal must perform a reception operation for receiving a paging message destined for a remote terminal in the Uu interface. Then, the relay terminal may receive the relay paging identifier from the base station. Then, the relay terminal may know the paging error based on the received relay paging identifier.

Meanwhile, the base station may transmit a paging message including the remote terminal identifier for paging the remote terminal in the Uu interface to the relay terminal in a paging error associated with or mapped to the relay paging identifier. Then, the relay terminal may receive the paging message from the base station in a paging error associated with or mapped to the relay paging identifier. The relay terminal can confirm that the paging message is destined for the remote terminal through the remote terminal identifier in the received paging message. Accordingly, the relay terminal may activate a side link with the remote terminal. Then, the relay terminal may transmit a paging message to the remote terminal through a side link. In this way, the paging error of the relay terminal may be determined as the paging identifier for the relay regardless of the remote terminal identifier. Accordingly, the number of paging errors in which the relay terminal performs a reception operation that requires receiving a paging message may be reduced. As such, the relay terminal may not perform the operation of receiving in all paging operations associated with the remote terminal identifier provided for each remote terminal. Accordingly, the frequency of the reception operation of the relay terminal may be reduced.

Remote terminal paging method for power saving of relay terminal

The base station may transmit a paging message for paging the remote terminal to the relay terminal in a paging operation in order to page the remote terminal. Accordingly, the relay terminal may receive the paging message for the remote terminal from the base station in the paging operation for the paging of the remote terminal. Then, the relay terminal may check the paging information for the remote terminal from the received paging message. Then, the relay terminal may deliver the paging information to the remote terminal. In such a situation, since the relay terminal performs a reception operation in all paging operations of each remote terminal, power is wasted and power saving cannot be achieved. In such an environment, a power saving method may be required in order to reduce power wasted in the process of the relay terminal relaying the remote terminal.

11 is a flowchart illustrating a third embodiment of a method in which a relay terminal relays a paging message.

11 is a method in which the relay terminal relays a paging message, the base station may transmit paging information for paging the remote terminal to the relay terminal by adding it to the paging message for the relay terminal transmitted to the paging error of the relay terminal (S1101) . Accordingly, the relay terminal may receive the paging message including the paging information of the remote terminal in the error of the relay terminal. Then, the relay terminal may obtain paging information for the remote terminal from the received paging message and transmit it to the remote terminal (S1102). Accordingly, the remote terminal may receive paging information from the relay terminal.

Meanwhile, the base station may transmit a paging message providing paging information to the remote terminal in a paging error of a related remote terminal for paging of the remote terminal (S1103). Accordingly, the remote terminal may separately receive the paging message in the paging operation of the remote terminal. In this case, the relay terminal may not separately perform a reception operation for receiving the paging message in the paging error of the remote terminal.

Meanwhile, the base station may use the remote terminal paging notifier to save power of the relay terminal.

12 is a flowchart illustrating a fourth embodiment of a method in which a relay terminal relays a paging message.

Referring to FIG. 12 , in a method in which a relay terminal relays a paging message, a base station may receive a message paging a remote terminal from a network or the like. Then, the base station may transmit the remote terminal paging notifier to the relay terminal associated with or mapped to the remote terminal to the paging operation of the relay terminal (S1201). Then, the relay terminal may receive the remote terminal paging notifier from the base station. Thereafter, the base station may transmit a paging message to the relay terminal in the paging error of the remote terminal (S1202). At this time, since the relay terminal has received the remote terminal paging notifier from the base station, it may receive a paging message for paging the remote terminal in a paging error related to the remote terminal identifier.

The relay terminal can confirm that the paging message is destined for the remote terminal through the remote terminal identifier in the received paging message. Accordingly, the relay terminal may activate a side link with the remote terminal. Then, the relay terminal may transmit a paging message to the remote terminal through the sidelink (S1203). In this way, since the relay terminal monitors the paging incident related to the remote terminal identifier only when the remote terminal paging notifier is received, the paging incident in which the relay terminal must receive the paging message can be reduced.

Here, when the base station configures the remote terminal paging notifier, the remote terminal paging notifier may be configured for each remote terminal to be paged. Accordingly, the remote terminal paging notifier may include a remote terminal identifier for each remote terminal to be paged. The remote terminal paging notifier may include a function value mapped to a remote terminal identifier for each remote terminal. Here, the function value may be a hash value generated by a hash algorithm.

Accordingly, the relay terminal may receive the remote terminal paging notifier including the function value mapped to the remote terminal identifier for each remote terminal. The relay terminal may recognize the function value from the received remote terminal paging notifier. And, the relay terminal can identify the remote terminal from the recognized function value. The relay terminal may receive the paging message provided by the base station by performing a reception operation in a paging error of the remote terminal associated with the received remote terminal paging notifier. The relay terminal may relay the paging procedure of the remote terminal to the paged remote terminal by using a side link. Additionally, the remote terminal paging notifier may include an already paged remote terminal identifier. Accordingly, the relay terminal can check the remote terminal identifier that has already been paged by the remote terminal paging notifier. In this case, the relay terminal may not perform the reception operation in the confirmed paging error of the remote terminal.

Meanwhile, when configuring the remote terminal paging notifier, the base station may configure the notifier for each paging occurrence. The base station may include paging notification information for paging the remote terminal for each paging occurrence in the paging occasions included in the remote terminal paging notifier for a certain period of time. Such paging notification information may be configured in the form of a bitmap corresponding to each paging origin. Accordingly, when the base station transmits a paging message for paging the remote terminal in each paging occurrence, the base station may set paging notification information in a location associated with or mapped to the paging occurrence in the remote terminal paging notifier. And, the base station may transmit the remote terminal paging notifier including the paging notification information to the relay terminal. Accordingly, the relay terminal may receive the remote terminal paging notifier including the paging notification information. The relay terminal may acquire paging notification information for each paging occurrence from the received remote terminal paging notifier. Accordingly, the relay terminal may perform a paging message reception operation in the paging origin included in the paging notification information. As such, the relay terminal may perform a paging message reception operation of the remote terminal when there is a paging notification in the paging error of the related remote terminal.

Meanwhile, the base station may configure the remote terminal paging notifier for relay terminals in common. Here, when the base station configures the remote terminal paging notifier for relay terminals in common, the remote terminal paging notifier may be transmitted in all paging occasions of the relay terminals or in a paging operation negotiated with the relay terminals. In this case, the base station and the relay terminal exchange information on the paging incident to transmit the remote terminal paging notifier in the relay terminal setup procedure, so that the relay terminal and the base station can specify the negotiated paging incident. When the base station transmits the remote terminal paging notifier in all paging occasions of the relay terminals, the relay terminal may perform a reception operation in the relay terminal's own paging occasion. When the base station transmits the remote terminal paging notifier in a paging error negotiated for each relay terminal, the relay terminal may perform a reception operation in the paging error negotiated with the relay terminal itself. Meanwhile, the base station may configure the remote terminal paging notifier for each relay terminal. In this way, when the base station configures the remote terminal paging notifier for each relay terminal, the remote terminal paging notifier may be transmitted to the corresponding relay terminal in a paging operation of the corresponding relay terminal. Accordingly, the relay terminal may receive the remote terminal paging notifier.

Meanwhile, the base station may configure the remote terminal paging notifier for each group of relay terminals. The base station may classify the relay terminals into groups. The base station may transmit the relay terminal group information classified in the relay terminal setting step to the relay terminal. In this case, the base station may set a group identifier for each classified relay terminal group, and may transmit the set group identifier to a corresponding relay terminal. The relay terminal may recognize the group it includes by receiving the group identifier.

Meanwhile, the base station may configure a paging message including remote terminal paging notifiers and group identifiers of relay terminals belonging to the relay terminal group. The base station may transmit the configured paging message to the relay terminal in paging operations of the relay terminals belonging to the group of the relay terminal. The relay terminal may receive the paging message and may check the group identifier in the received paging message. The relay terminal may obtain the remote terminal paging notifier from the paging message when the confirmed group identifier is the group identifier of the group to which it belongs. If there is a remote terminal paging notifier related to the remote terminal it manages in the remote terminal paging notifier, the relay terminal may deliver it to the corresponding remote terminal.

Control of paging relay function of relay terminal led by remote terminal

The remote terminal may be located in the service area of the base station and directly receive paging information provided by the base station through the Uu interface. In this way, when the remote terminal can receive the paging message from the Uu interface, it may not receive the paging message from the PC5 site link transmitted by the relay terminal. In this case, the remote terminal may inform the relay terminal of the interruption state of the reception of the paging message transmitted from the PC5 sidelink. In this case, the remote terminal may inform the relay terminal of the reception stop status of the paging message using a relay function control message. Alternatively, the remote terminal may inform the relay terminal of the reception stop status of the paging message using another control message including a paging relay function control field indicating reception stop status information.

Meanwhile, the remote terminal may stop the function of directly receiving the paging message provided by the base station through the Uu interface even when the base station is located in the service area. Alternatively, the remote terminal cannot directly receive the paging message provided by the base station on the Uu interface when the base station leaves the service area. In this case, the remote terminal may request transmission of the paging service to the relay terminal. Upon receiving such a request, the relay terminal may resume relaying of the paging message.

How a relay terminal acquires a paging error of a remote terminal

The relay terminal may receive a paging message transmitted from the base station to the remote terminal and relay and transmit paging information to the remote terminal. To this end, the relay terminal may need to manage a paging error of the remote terminal and the remote terminal identifier. To this end, the remote terminal may provide the relay terminal with information on the paging occurrence to observe the paging message and the remote terminal identifier information for identifying the remote terminal in the signal procedure for changing the RRC state to the RRC idle state or RRC inactive state. . Accordingly, the relay terminal may receive and manage information on a paging occurrence to observe a paging message and remote terminal identifier information for identifying the remote terminal from the remote terminal. In more detail, the information about the paging operation provided by the remote terminal to the relay terminal may include remote terminal specific DRX cycle information. Here, the relay terminal may transmit the remote terminal identifier received from the remote terminal to the base station. In this case, the relay terminal may transmit the remote terminal identifier to the base station using a dedicated (dedicated) RRC (radio resource control) message. Accordingly, the base station may receive the remote terminal identifier from the relay terminal. As a result, the base station can determine to which relay terminal the remote terminal is accessing. Meanwhile, the base station may provide, to the relay terminal, information on a paging error to observe a paging message transmitted to the remote terminal and remote terminal identifier information for identifying the remote terminal. Accordingly, the relay terminal may receive and manage information on a paging occurrence to observe a paging message and remote terminal identifier information for identifying a remote terminal from the base station. Specifically, the information on the paging error provided by the base station to the relay terminal may include common DRX cycle information.

In this way, the remote terminal can provide the remote terminal identifier information to the relay terminal so that the relay terminal can obtain information on the paging occurrence for which the relay terminal will observe the paging message. The base station may also provide the remote terminal identifier information to the relay terminal so that the relay terminal can obtain information on the paging incident to observe the paging message. In this way, the relay terminal may receive the remote terminal identifier information from the remote terminal or the base station. In this case, the relay terminal may calculate the paging error of the remote terminal from the remote terminal identifier, and may perform a receiving operation of the paging message from the calculated paging error. More specifically, the relay terminal may calculate the paging error of the remote terminal using the remote terminal identifier and the common DRX cycle received from the base station, and may perform the paging message reception operation from the calculated paging error. . Alternatively, the relay terminal may calculate the paging occurrence of the remote terminal using the remote terminal identifier and the remote terminal specific DRX cycle received from the remote terminal, and may perform a receiving operation of the paging message from the calculated paging error.

On the other hand, the relay terminal may check the remote terminal identifier when the paging message is received in the paging error. In this case, if the remote terminal identifier is included in the paging message, the relay terminal may relay and transmit the paging information to the remote terminal. As a method for relaying paging information by the relay terminal, at least one of an individual transmission method, a broadcast type transmission method, and a group type transmission method may be used.

On the other hand, the relay terminal can manage only the paging error of the remote terminal. To this end, the remote terminal may provide the relay terminal with information on the paging occurrence to observe the paging message in the signaling procedure for changing the RRC state to the RRC idle state or the RRC inactive state. Accordingly, the relay terminal may receive and manage the information on the paging operation to observe the paging message from the remote terminal. On the other hand, the base station may provide the relay terminal with information on the paging error to observe the paging message transmitted to the remote terminal as a destination. Accordingly, the relay terminal can receive and manage information on a paging incident to observe a paging message destined for a remote terminal from the base station.

In this case, since the relay terminal does not manage the remote terminal identifier, when a paging message is received in a paging operation for a paging message destined for a remote terminal, it cannot determine which remote terminal the paging message is for. Accordingly, the relay terminal may transmit a paging message to all remote terminals being managed. In this case, the base station may use a broadcast transmission scheme or an individual transmission scheme.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software. Examples of computer-readable media may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions may include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa. In addition, the above-described method or apparatus may be implemented by combining all or part of its configuration or function, or may be implemented separately.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that it can be done.

Claims (19)

A method of operating a relay terminal for relaying wireless communication between a base station and a remote terminal in a communication system, the method comprising:
recognizing the relay request of the remote terminal for the system information provided by the base station;
obtaining the system information from the base station; and
A method of operating a relay terminal comprising transmitting the system information to the remote terminal. The method according to claim 1,
Recognizing the relay request of the remote terminal for the system information provided by the base station,
receiving a request message notifying a relay request for the system information from the remote terminal; and
and recognizing a relay request for the system information in the received request message. The method according to claim 1,
Recognizing the relay request of the remote terminal for the system information provided by the base station,
receiving relay request identification information capable of distinguishing a relay request of the remote terminal for system information from the base station;
receiving a discovery message including the relay request identification information from the remote terminal; and
and recognizing the relay request for the system information by acquiring the relay request identification information from the received discovery message. 4. The method of claim 3,
The relay request identification information is an identifier for a request logical channel used by the remote terminal to transmit the discovery message to request transmission of the system information. 4. The method of claim 3,
The relay request identification information is a request discovery resource information used by the remote terminal to transmit the discovery message in order to request transmission of the system information. The method according to claim 1,
Acquiring the system information from the base station according to the relay request comprises:
requesting the base station to transmit the system information; and
and receiving the system information in response to the transmission request from the base station. 7. The method of claim 6,
The step of requesting the transmission of the system information to the base station,
selecting a first PRACH sequence requesting transmission of the system information designated by the base station from physical random access channel (PRACH) sequences; and
and transmitting the first PRACH sequence to the base station through a PRACH. The method according to claim 1,
receiving a relay stop request for the system information from the remote terminal; and
The method of operating a relay terminal, further comprising stopping transmission of the system information according to the relay stop request. A method of operating a relay terminal for relaying wireless communication between a base station and a remote terminal in a communication system, the method comprising:
receiving, from the remote terminal, information related to a paging operation for receiving a paging message destined for the remote terminal;
receiving the paging message from the base station by performing a monitoring operation on the paging occurrence indicated by the association information;
determining a destination of the paging message based on information included in the paging message; and
and transmitting the paging message to the remote terminal when the destination of the paging message is the remote terminal. 10. The method of claim 9,
The related information is a remote terminal identifier,
Receiving the paging message from the base station by performing a monitoring operation in the paging occurrence indicated by the association information,
performing a monitoring operation on the paging occurrence associated with the remote terminal identifier; and
and receiving the paging message from the base station in the paging error. 10. The method of claim 9,
The association information is a remote terminal identifier and a discontinuous reception (DRX) period of the remote terminal,
Receiving the paging message from the base station by performing a monitoring operation in the paging occurrence indicated by the association information,
performing a monitoring operation on the paging occurrence associated with the remote terminal identifier and the DRX cycle; and
and receiving the paging message from the base station in the paging error. 10. The method of claim 9,
The related information is a remote terminal identifier,
Further comprising the step of transmitting the remote terminal identifier to the base station, the operation method of the relay terminal. 10. The method of claim 9,
Transmitting the paging message to the remote terminal comprises:
The method of operating a relay terminal, characterized in that the relay terminal transmits the paging message to the remote terminal using an individual transmission method, a broadcast transmission method or a group transmission method. 10. The method of claim 9,
receiving a request to stop relaying the paging message from the remote terminal; and
The method of operating a relay terminal, further comprising stopping relay of the paging message destined for the remote terminal according to the relay stop request. A relay terminal for relaying wireless communication between a base station and a remote terminal in a communication system, comprising:
processor;
a memory in electronic communication with the processor; and
Including instructions stored in the memory,
When the instructions are executed by the processor, the instructions are executed by the relay terminal,
recognizing the relay request of the remote terminal for the system information provided by the base station;
obtain the system information from the base station; and
and cause transmission of the system information to the remote terminal. 16. The method of claim 15,
When recognizing the relay request of the remote terminal for the system information provided by the base station, the commands are
receiving a request message informing of a relay request for the system information from the remote terminal; and
and causing recognition of the relay request for the system information in the received request message. 16. The method of claim 15,
When recognizing the relay request of the remote terminal for the system information provided by the base station, the commands are
receive relay request identification information capable of distinguishing a relay request of the remote terminal for system information from the base station;
receive a discovery message including the relay request identification information from the remote terminal; and
and obtaining the relay request identification information from the received discovery message to cause recognition of the relay request for the system information. 18. The method of claim 17,
The relay request identification information is an identifier for a request logical channel used by the remote terminal to transmit the discovery message to request transmission of the system information. 18. The method of claim 17,
The relay request identification information is a request discovery resource information used by the remote terminal to transmit the discovery message to request the transmission of the system information, the relay terminal.

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