Communication terminals, base station equipment, and communication systems

Abstract

This system provides a communication system and remote UE that enable multicast transmission by applying access and backhaul integration. [Solution] The communication system includes a base station device, a relay UE, and a remote UE, wherein the remote UE transmits a request to the base station device to transmit system information via the relay UE. The remote UE receives the system information from the base station device via the relay UE. The system information includes an RRC message.

Description

Technical Field

[0001] This disclosure relates to wireless communication technologies.

Background Art

[0002] In the 3GPP (3rd Generation Partnership Project), which is a standardization organization for mobile communication systems, the radio section is called Long Term Evolution (LTE), and for the overall system configuration including the core network and radio access network (hereinafter collectively referred to as the network), a communication method called System Architecture Evolution (SAE) is being studied (for example, Non-Patent Documents 1 to 5). This communication method is also called the 3.9G (3.9 Generation) system.

[0003] As the access method of LTE, OFDM (Orthogonal Frequency Division Multiplexing) is used in the downlink direction, and SC-FDMA (Single Carrier Frequency Division Multiple Access) is used in the uplink direction. Also, unlike W-CDMA (Wideband Code Division Multiple Access), LTE does not include circuit switching and is only a packet communication method.

[0004] The decisions made by 3GPP regarding the frame structure in LTE systems, as described in Non-Patent Document 1 (Chapter 5), will be explained using Figure 1. Figure 1 is an explanatory diagram showing the structure of a radio frame used in an LTE communication system. In Figure 1, one radio frame is 10ms. A radio frame is divided into 10 subframes of equal size. Each subframe is divided into two slots of equal size. Downlink synchronization signals are included in the 1st and 6th subframes of each radio frame. The synchronization signals consist of a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS).

[0005] The 3GPP's decisions regarding channel configuration in LTE systems are described in Non-Patent Document 1 (Chapter 5). It is assumed that the same channel configuration as non-CSG cells will be used in CSG (Closed Subscriber Group) cells.

[0006] The Physical Broadcast Channel (PBCH) is a channel used for downlink transmission from base station equipment (hereinafter sometimes simply referred to as "base station") to communication terminal equipment (hereinafter sometimes simply referred to as "mobile terminal") and other such devices. A PBCH transport block is mapped to four subframes within a 40ms interval. There is no explicit signaling at 40ms timing.

[0007] The Physical Control Format Indicator Channel (PCFICH) is a channel used for downlink transmission from the base station to the communication terminal. The PCFICH notifies the communication terminal of the number of OFDM (Orthogonal Frequency Division Multiplexing) symbols to be used for PDCCHs. The PCFICH is transmitted for each subframe.

[0008] The Physical Downlink Control Channel (PDCCH) is the channel used for downlink transmission from the base station to the communication terminal. The PDCCH notifies resource allocation information for the Downlink Shared Channel (DL-SCH), one of the transport channels described later, resource allocation information for the Paging Channel (PCH), another transport channel described later, and HARQ (Hybrid Automatic Repeat reQuest) information related to the DL-SCH. The PDCCH carries the Uplink Scheduling Grant. The PDCCH also carries Ack (Acknowledgement) / Nack (Negative Acknowledgement), which are response signals to uplink transmissions. The PDCCH is also called the L1 / L2 control signal.

[0009] The Physical Downlink Shared Channel (PDSCH) is a channel used for downlink transmission from a base station to a communication terminal. The PDSCH is mapped to the Downlink Shared Channel (DL-SCH), which is a transport channel, and the PCH, which is also a transport channel.

[0010] A physical multicast channel (PMCH) is a channel used for downlink transmission from a base station to a communication terminal. A multicast channel (MCH), which is a transport channel, is mapped to the PMCH.

[0011] The Physical Uplink Control Channel (PUCCH) is the channel used for uplink transmission from the communication terminal to the base station. The PUCCH carries the Ack / Nack response signal for downlink transmission. The PUCCH also carries Channel State Information (CSI). The CSI consists of the Rank Indicator (RI), Precoding Matrix Indicator (PMI), and Channel Quality Indicator (CQI) report. RI is the rank information of the channel matrix in MIMO. PMI is information of the precoding weight matrix used in MIMO. CQI is quality information indicating the quality of the received data or the quality of the communication channel. The PUCCH also carries a Scheduling Request (SR).

[0012] The Physical Uplink Shared Channel (PUSCH) is a channel used for uplink transmission from a communication terminal to a base station. The Uplink Shared Channel (UL-SCH), which is one of the transport channels, is mapped to the PUSCH.

[0013] The Physical Hybrid ARQ Indicator Channel (PHICH) is the channel used for downlink transmission from the base station to the communication terminal. PHICH carries the Ack / Nack, which is the response signal to uplink transmissions. The Physical Random Access Channel (PRACH) is the channel used for uplink transmission from the communication terminal to the base station. PRACH carries the random access preamble.

[0014] The downlink reference signal (RS) is a well-known symbol in LTE communication systems. Five types of downlink reference signals are defined: Cell-specific Reference Signal (CRS), MBSFN Reference Signal, UE-specific Reference Signal (UE-specific), Demodulation Reference Signal (DM-RS), Positioning Reference Signal (PRS), and Channel State Information Reference Signal (CSI-RS). One measurement of the physical layer of a communication terminal is the Reference Signal Received Power (RSRP).

[0015] Similarly, the uplink reference signals are also known symbols for LTE communication systems. Two types of uplink reference signals are defined: the Demodulation Reference Signal (DM-RS) and the Sounding Reference Signal (SRS).

[0016] This section explains the transport channel described in Non-Patent Document 1 (Chapter 5). Of the downlink transport channels, the broadcast channel (BCH) broadcasts to the entire coverage of the base station (cell). The BCH is mapped to the physical broadcast channel (PBCH).

[0017] Downlink Shared Channels (DL-SCH) are subject to retransmission control using HARQ (Hybrid ARQ). DL-SCH can broadcast to the entire coverage of a base station (cell). DL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also called persistent scheduling. DL-SCH supports discontinuous reception (DRX) for communication terminals to reduce power consumption. DL-SCH is mapped to Physical Downlink Shared Channels (PDSCH).

[0018] Paging Channels (PCHs) support DRX for communication terminals to enable low power consumption for those terminals. PCHs are required to broadcast across the entire coverage of a base station (cell). PCHs are mapped to physical resources, such as Physical Downlink Shared Channels (PDSCHs), which are dynamically available for traffic.

[0019] Multicast channels (MCHs) are used for broadcasting across the entire coverage of a base station (cell). MCHs support SFN synthesis of MBMS (Multimedia Broadcast Multicast Service) services (MTCH and MCCH) in multi-cell transmission. MCHs support quasi-static resource allocation. MCHs are mapped to PMCHs.

[0020] Among the uplink transport channels, the Uplink Shared Channel (UL-SCH) is subject to retransmission control using HARQ (Hybrid ARQ). UL-SCH supports dynamic or semi-static resource allocation. UL-SCH is mapped to the Physical Uplink Shared Channel (PUSCH).

[0021] Random Access Channels (RACHs) are limited to control information. RACHs carry a risk of collisions. RACHs are mapped to Physical Random Access Channels (PRACHs).

[0022] This section explains HARQ. HARQ is a technology that improves the communication quality of a transmission path by combining Automatic Repeat reQuest (ARQ) and Forward Error Correction. HARQ has the advantage that error correction works effectively through retransmission even on transmission paths where the communication quality changes. In particular, it is possible to achieve further quality improvement by combining the reception results of the initial transmission and the retransmission during retransmission.

[0023] Here is an example of how to retransmit data. If the receiving side is unable to correctly decode the received data, in other words, if a CRC (Cyclic Redundancy Check) error occurs (CRC=NG), the receiving side sends "Nack" to the sending side. Upon receiving "Nack," the sending side retransmits the data. If the receiving side is able to correctly decode the received data, in other words, if no CRC error occurs (CRC=OK), the receiving side sends "Ack" to the sending side. Upon receiving "Ack," the sending side sends the next data.

[0024] This section explains the logical channel described in Non-Patent Document 1 (Chapter 6). The Broadcast Control Channel (BCCH) is a downstream channel for broadcast system control information. The BCCH, being a logical channel, is mapped to the broadcast channel (BCH), which is a transport channel, or to the downstream shared channel (DL-SCH).

[0025] The Paging Control Channel (PCCH) is a downlink channel used to transmit changes to paging information and system information. The PCCH is used when the network does not know the cell location of a communication terminal. As a logical channel, the PCCH is mapped to the Paging Channel (PCH), which is a transport channel.

[0026] The Common Control Channel (CCCH) is a channel for transmit control information between a communication terminal and a base station. The CCCH is used when a communication terminal does not have an RRC connection with the network. In the downlink direction, the CCCH is mapped to the downlink common channel (DL-SCH), which is a transport channel. In the uplink direction, the CCCH is mapped to the uplink common channel (UL-SCH), which is a transport channel.

[0027] A Multicast Control Channel (MCCH) is a downlink channel for one-to-many transmission. MCCHs are used to transmit MBMS control information for one or more MCCHs from the network to communication terminals. MCCHs are only used by communication terminals receiving MBMS. MCCHs are mapped to the Multicast Channel (MCH), which is the transport channel.

[0028] The Dedicated Control Channel (DCCH) is a channel that transmits dedicated control information between a communication terminal and a network on a one-to-one basis. The DCCH is used when the communication terminal has an RRC connection. The DCCH is mapped to the UL-SCH in the uplink and to the DL-SCH in the downlink.

[0029] The Dedicated Traffic Channel (DTCH) is a channel for one-to-one communication to an individual communication terminal for transmitting user information. The DTCH exists in both the uplink and the downlink. The DTCH is mapped to the UL-SCH in the uplink and to the DL-SCH in the downlink.

[0030] The Multicast Traffic Channel (MTCH) is a downlink channel for transmitting traffic data from the network to a communication terminal. The MTCH is a channel used only for communication terminals during MBMS reception. The MTCH is mapped to the Multicast Channel (MCH).

[0031] CGI refers to the Cell Global Identifier. ECGI refers to the E-UTRAN Cell Global Identifier. In LTE, the later LTE-A (Long Term Evolution Advanced), and UMTS (Universal Mobile Telecommunication System), Closed Subscriber Group (CSG) cells are introduced.

[0032] Location tracking of communication terminals is performed in units of areas consisting of one or more cells. Location tracking is performed to track the location of communication terminals even when they are in standby mode, and to enable them to be called, in other words, to allow them to receive calls. This area used for location tracking of communication terminals is called the tracking area.

[0033] Furthermore, 3GPP is working on the Long Term Evolution Advanced (LTE-A) standard as Release 10 (see Non-Patent Documents 3 and 4). LTE-A is based on the LTE wireless communication method and incorporates several new technologies.

[0034] In LTE-A systems, carrier aggregation (CA), which involves aggregating two or more component carriers (CCs) to support wider transmission bandwidths up to 100 MHz, is being considered. CA is described in Non-Patent Document 1.

[0035] When a CA is configured, the UE (User Interface Device), which is a communication terminal, has a single RRC connection to the network (NW). In the RRC connection, one serving cell provides NAS mobility information and security input. This cell is called the Primary Cell (PCell). On the downlink, the carrier corresponding to the PCell is the Downlink Primary Component Carrier (DL PCC). On the uplink, the carrier corresponding to the PCell is the Uplink Primary Component Carrier (UL PCC).

[0036] Depending on the capabilities of the UE, secondary cells (SCells) are configured to form a set of serving cells together with PCells. On the downlink, the carrier corresponding to the SCell is the Downlink Secondary Component Carrier (DL SCC). On the uplink, the carrier corresponding to the SCell is the Uplink Secondary Component Carrier (UL SCC).

[0037] A set of serving cells consisting of one PCell and one or more SCells is configured for one UE.

[0038] Furthermore, new technologies in LTE-A include technologies that support wider bandwidths (Wider bandwidth extension) and technologies such as Coordinated Multiple Point transmission and reception (CoMP). The CoMP technology being considered by 3GPP for LTE-A is described in Non-Patent Document 1.

[0039] Furthermore, 3GPP is considering using small eNBs (sometimes referred to as "small-scale base station equipment") that constitute small cells to cope with the enormous traffic of the future. For example, technologies are being considered to increase communication capacity by improving frequency utilization efficiency by installing a large number of small eNBs to constitute a large number of small cells. Specifically, there is dual connectivity (abbreviated as DC), in which a UE connects to and communicates with two eNBs. DC is described in Non-Patent Document 1.

[0040] In some cases, among eNBs that perform dual connectivity (DC), one is called the "master eNB (abbreviated as MeNB)" and the other is called the "secondary eNB (abbreviated as SeNB)".

[0041] Mobile network traffic is on the rise, and communication speeds are also increasing. Further speed increases are expected once LTE and LTE-A are fully operational.

[0042] Furthermore, in response to the increasing sophistication of mobile communications, a fifth-generation (sometimes referred to as "5G") wireless access system is being considered, with the goal of launching services after 2020. For example, in Europe, the METIS organization has compiled the requirements for 5G (see Non-Patent Document 5).

[0043] In 5G wireless access systems, the requirements include achieving 1000 times the system capacity, 100 times the data transmission speed, one-tenth (1 / 10) the data processing delay, and 100 times the number of simultaneous connections for communication terminals compared to LTE systems, while also achieving further reductions in power consumption and equipment costs.

[0044] To meet these requirements, 3GPP is working on the 5G standard as Release 15 (see Non-Patent Documents 6-19). The technology for the wireless portion of 5G is called "New Radio Access Technology" ("New Radio" is abbreviated as "NR").

[0045] The NR system is being developed based on the LTE system and LTE-A system, but the following changes and additions have been made compared to the LTE system and LTE-A system.

[0046] For NR access, OFDM is used for the downstream direction, and OFDM and DFT-s-OFDM (DFT-spread-OFDM) are used for the upstream direction.

[0047] NR allows for the use of higher frequencies compared to LTE, in order to improve transmission speed and reduce processing delays.

[0048] In NR (Noise Reduction), cell coverage is ensured by forming a narrow beam-shaped transmission and reception range (beamforming) and changing the direction of the beam (beam sweeping).

[0049] In NR frame configurations, various subcarrier intervals, i.e., various numerologies, are supported. In NR, regardless of the numerology, one subframe is 1 millisecond, and one slot consists of 14 symbols. Furthermore, the number of slots contained in one subframe is one for a numerology with a subcarrier interval of 15 kHz, and increases proportionally with the subcarrier interval for other numerologies (see Non-Patent Document 13 (3GPP TS38.211)).

[0050] In NR, the downlink synchronization signal is transmitted from the base station as a synchronization signal burst (SS burst) at a predetermined period and for a predetermined duration. The SS burst consists of a synchronization signal block (SS block) for each beam of the base station.

[0051] During the duration of the SS burst, the base station transmits SS blocks of each beam, switching between beams. The SS block consists of P-SS, S-SS, and PBCH.

[0052] In noise reduction (NR), the effect of phase noise is reduced by adding a Phase Tracking Reference Signal (PTRS) as the downstream reference signal. Similarly, a PTRS is also added to the upstream reference signal.

[0053] In NR, Slot Format Indication (SFI) information has been added to the PDCCH to allow for flexible switching between DL / UL within a slot.

[0054] Furthermore, in NR, a portion of the carrier frequency band (sometimes referred to as the Bandwidth Part (BWP)) is pre-configured by the base station for the UE, and the UE performs transmission and reception with the base station in the BWP, thereby reducing the power consumption of the UE.

[0055] 3GPP is considering several data center configurations, including a data center with LTE and NR base stations connected to an EPC, a data center with NR base stations connected to a 5G core system, and a data center with LTE and NR base stations connected to a 5G core system (see Non-Patent Documents 12, 16, and 19).

[0056] Furthermore, 3GPP is considering supporting services (or applications) using side-link (SL) communication (also known as PC5 communication) in both the Evolved Packet System (EPS) described later and the 5G core system (see Non-Patent Documents 1, 16, 20, 21, 22, and 23). SL communication takes place between terminals. Examples of services using SL communication include V2X (Vehicle-to-everything) services and proximity services. In SL communication, not only direct communication between terminals but also communication between the UE and the NW via relay has been proposed (see Non-Patent Documents 20, 23, and 27).

[0057] Furthermore, 3GPP is considering several new technologies. For example, multicast using NR is being considered. In multicast using NR, for example, a reliable multicast scheme and dynamic switching between point-to-multipoint (PTM) transmission and point-to-point (PTP) transmission are being considered (see Non-Patent Documents 28, 29, and 30). Multicast in base stations with a CU (Central Unit) / DU (Distributed Unit) separation configuration is also being considered (see Non-Patent Document 31).

[0058] Another example being considered is Integrated Access and Backhaul (IAB), which involves wirelessly performing both the access link (the link between the UE and the base station) and the backhaul link (the link between base stations) (see Non-Patent Documents 16, 32, and 33). [Prior art documents] [Non-patent literature]

[0059] [Non-Patent Document 1] 3GPP TS 36.300 V16.2.0 [Non-Patent Document 2] 3GPP S1-083461 [Non-Patent Document 3] 3GPP TR 36.814 V9.2.0 [Non-Patent Document 4] 3GPP TR 36.912 V16.0.0 [Non-Patent Document 5] “Scenarios, requirements and KPIs for 5G mobile and wireless system”, ICT-317669-METIS / D1.1 [Non-Patent Document 6] 3GPP TR 23.799 V14.0.0 [Non-Patent Document 7] 3GPP TR 38.801 V14.0.0 [Non-licensed document 8] 3GPP TR 38.802 V14.2.0

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[0060] 5G base stations can support Integrated Access and Backhaul (IAB) (see Non-Patent Document 16 (TS38.300 V16.4.0)). That is, multicast can be performed using base stations that support IAB (hereinafter sometimes referred to as IAB base stations). However, the detailed configuration method for multicast on IAB base stations has not been disclosed. Therefore, a problem arises in that multicast using IAB base stations cannot be realized.

[0061] In view of the above issues, one of the objectives of this disclosure is to enable multicast transmission in a communication system to which access and backhaul integration is applied. [Means for solving the problem]

[0062] The communication system according to this disclosure includes a base station device, a relay UE, and a remote UE, wherein the remote UE transmits a request to transmit system information to the base station device via the relay UE. [Effects of the Invention]

[0063] This disclosure provides the effect of enabling multicast transmission in communication systems to which access and backhaul integration is applied.

[0064] The purpose, features, aspects, and advantages of this disclosure will become clearer from the following detailed description and accompanying drawings. [Brief explanation of the drawing]

[0065] [Figure 1] This is an explanatory diagram showing the configuration of wireless frames used in LTE communication systems. [Figure 2] This block diagram shows the overall configuration of the LTE communication system 200 as discussed in 3GPP. [Figure 3]This is a block diagram showing the overall configuration of the NR communication system 210 as discussed in 3GPP. [Figure 4] This is a diagram illustrating the configuration of a data center using eNBs and gNBs connected to the EPC. [Figure 5] This is a diagram showing the configuration of the DC using gNB connected to the NG core. [Figure 6] This is a diagram showing the configuration of the DC with eNBs and gNBs connected to the NG core. [Figure 7] This is a diagram showing the configuration of the DC with eNBs and gNBs connected to the NG core. [Figure 8] Figure 2 is a block diagram showing the configuration of the mobile terminal 202. [Figure 9] Figure 2 is a block diagram showing the configuration of base station 203. [Figure 10] This block diagram shows the configuration of MME. [Figure 11] This is a block diagram showing the configuration of the 5GC section. [Figure 12] This is a flowchart illustrating the general process from cell search to standby operation performed by a communication terminal (UE) in an LTE communication system. [Figure 13] This figure shows an example of a cell configuration in an NR system. [Figure 14] This figure shows the first half of a sequence illustrating an example of multicast configuration at an IAB base station in Embodiment 1. [Figure 15] This figure shows the latter part of a sequence illustrating an example of multicast configuration at an IAB base station in Embodiment 1. [Figure 16] This figure shows an example of a multicast connection from an IAB base station in Embodiment 2. [Figure 17] This diagram shows the protocol stack between the IAB donor CU and the UE in Embodiment 2. [Figure 18] This figure shows another example of a protocol stack between the IAB donor CU and UE in Embodiment 2. [Figure 19]This figure shows an example of multicast transmission from an IAB base station in Embodiment 2. [Figure 20] This figure shows another example of multicast transmission from an IAB base station in Embodiment 2. [Figure 21] This figure shows another example of multicast transmission from an IAB base station in Embodiment 2. [Figure 22] This figure shows another example of multicast transmission from an IAB base station in Embodiment 2. [Figure 23] This figure shows a modified example of Embodiment 2, in which multiple PTM legs are provided in the IAB node. [Figure 24] This sequence diagram shows an example of a scheduling method for communication from a gNB to a remote UE via a relay UE in Embodiment 3. [Figure 25] The following is a sequence diagram illustrating another example of a method for scheduling communication from a gNB to a remote UE via a relay UE, according to Embodiment 3. [Figure 26] The following is a sequence diagram illustrating another example of a method for scheduling communication from a gNB to a remote UE via a relay UE, according to Embodiment 3. [Figure 27] The following is a sequence diagram illustrating another example of a method for scheduling communication from a gNB to a remote UE via a relay UE, according to Embodiment 3. [Figure 28] The following is a sequence diagram illustrating another example of a method for scheduling communication from a gNB to a remote UE via a relay UE, according to Embodiment 3. [Figure 29] The following is a sequence diagram illustrating another example of a method for scheduling communication from a gNB to a remote UE via a relay UE, according to Embodiment 3. [Figure 30] This sequence diagram shows an example of a scheduling method for communication from a remote UE to a gNB via a relay UE, in a modified example of Embodiment 3, Part 1. [Figure 31]This sequence diagram shows another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in the case of a modification 1 of Embodiment 3. [Figure 32] This sequence diagram shows another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in the case of a modification 1 of Embodiment 3. [Figure 33] This sequence diagram shows another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in the case of a modification 1 of Embodiment 3. [Figure 34] This sequence diagram shows another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in the case of a modification 1 of Embodiment 3. [Figure 35] This sequence diagram shows another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in the case of a modification 1 of Embodiment 3. [Figure 36] This sequence diagram shows another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in the case of a modification 1 of Embodiment 3. [Figure 37] This sequence diagram shows another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in the case of a modification 1 of Embodiment 3. [Figure 38] This sequence diagram shows another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in the case of a modification 1 of Embodiment 3. [Figure 39] This sequence diagram shows another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in the case of a modification 1 of Embodiment 3. [Figure 40] This sequence diagram shows another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in the case of a modification 1 of Embodiment 3. [Modes for carrying out the invention]

[0066] The communication system and base station according to the embodiments of this disclosure will be described in detail below with reference to the drawings.

[0067] Embodiment 1. Figure 2 is a block diagram showing the overall configuration of the LTE communication system 200 being discussed in 3GPP. Figure 2 will be explained below. The radio access network is called E-UTRAN (Evolved Universal Terrestrial Radio Access Network) 201. The mobile terminal equipment (hereinafter referred to as "User Equipment: UE") 202, which is a communication terminal device, can communicate wirelessly with the base station equipment (hereinafter referred to as "Base Station (E-UTRAN NodeB: eNB)") 203 and transmits and receives signals wirelessly.

[0068] Here, "communication terminal equipment" includes not only mobile terminal equipment such as portable mobile phone terminals, but also stationary devices such as sensors. In the following explanation, "communication terminal equipment" may sometimes be simply referred to as "communication terminal."

[0069] If the control protocol for the mobile terminal 202, such as RRC (Radio Resource Control), and the user plane (hereinafter sometimes referred to as U-Plane), such as PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer), are terminated at base station 203, then E-UTRAN is composed of one or more base stations 203.

[0070] The control protocol RRC (Radio Resource Control) between the mobile terminal 202 and the base station 203 performs functions such as broadcasting, paging, and RRC connection management. The states of the base station 203 and the mobile terminal 202 in RRC are RRC_IDLE and RRC_CONNECTED.

[0071] In RRC_IDLE mode, tasks such as PLMN (Public Land Mobile Network) selection, System Information (SI) notification, paging, cell re-selection, and mobility are performed. In RRC_CONNECTED mode, mobile terminals have an RRC connection and can send and receive data with the network. In RRC_CONNECTED mode, tasks such as handover (HO) and neighbor cell measurement are also performed.

[0072] Base station 203 consists of one or more eNB207 units. The system, comprising the core network EPC (Evolved Packet Core) and the wireless access network E-UTRAN201, is called EPS (Evolved Packet System). The EPC and E-UTRAN201 are sometimes collectively referred to as the "network."

[0073] The eNB207 is connected to a Mobility Management Entity (MME), or a Serving Gateway (S-GW), or an MME / S-GW unit (hereinafter sometimes referred to as "MME unit") 204 including both an MME and an S-GW, via an S1 interface, and control information is communicated between the eNB207 and the MME unit 204. Multiple MME units 204 may be connected to a single eNB207. The eNB207s are connected to each other via an X2 interface, and control information is communicated between them.

[0074] The MME unit 204 controls the connection between the higher-level device, specifically the higher-level node, which is the base station eNB 207, and the mobile terminal (UE) 202. The MME unit 204 constitutes the core network EPC. The base station 203 constitutes the E-UTRAN 201.

[0075] The base station 203 may constitute one cell or multiple cells. Each cell has a predetermined range called coverage, which is the range within which it can communicate with the mobile terminal 202, and wireless communication is performed with the mobile terminal 202 within that coverage. When one base station 203 constitutes multiple cells, each cell is configured to communicate with the mobile terminal 202.

[0076] Figure 3 is a block diagram showing the overall configuration of the 5G communication system 210 being discussed in 3GPP. Figure 3 will now be explained. The radio access network is called NG-RAN (Next Generation Radio Access Network) 211. UE 202 can communicate wirelessly with NR base station equipment (hereinafter referred to as "NR base station (NG-RAN NodeB: gNB)") 213 and transmits and receives signals wirelessly. The core network is called the 5G Core (5GC).

[0077] If the control protocol for UE202, such as RRC (Radio Resource Control), and the user plane (hereinafter sometimes referred to as U-Plane), such as SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer), are terminated at the NR base station 213, then the NG-RAN is composed of one or more NR base stations 213.

[0078] The functionality of the Radio Resource Control (RRC) control protocol between UE202 and NR base station 213 is the same as in LTE. The states of NR base station 213 and UE202 in RRC are RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE.

[0079] RRC_IDLE and RRC_CONNECTED are the same as in the LTE system. RRC_INACTIVE means that the connection between the 5G core and NR base station 213 is maintained while system information (SI) broadcasting, paging, cell re-selection, and mobility are performed.

[0080] The gNB217 is connected via an NG interface to an Access and Mobility Management Function (AMF), a Session Management Function (SMF), or a User Plane Function (UPF), or an AMF / SMF / UPF unit (hereinafter sometimes referred to as the "5GC unit") 214 that includes AMF, SMF, and UPF. Control information and / or user data are communicated between the gNB217 and the 5GC unit 214. The NG interface is a collective term for the N2 interface between the gNB217 and AMF, the N3 interface between the gNB217 and UPF, the N11 interface between AMF and SMF, and the N4 interface between UPF and SMF. Multiple 5GC units 214 may be connected to a single gNB217. The gNB217s are connected to each other via an Xn interface, and control information and / or user data are communicated between them.

[0081] The 5GC unit 214 is a higher-level device, specifically a higher-level node, and distributes paging signals to one or more base stations 203 and / or base station 213. The 5GC unit 214 also performs mobility control in the idle state. The 5GC unit 214 manages the tracking area list when the mobile terminal 202 is in the idle state, in the inactive state, and in the active state. The 5GC unit 214 initiates the paging protocol by sending a paging message to a cell belonging to the tracking area where the mobile terminal 202 is registered.

[0082] Like base station 203, NR base station 213 may also consist of one or more cells. When one NR base station 213 consists of multiple cells, each cell is configured to communicate with UE 202.

[0083] The gNB217 may be divided into a Central Unit (CU) 218 ​​and a Distributed Unit (DU) 219. One CU218 is configured within the gNB217. One or more DU219s are configured within the gNB217. The CU218 is connected to the DU219 via an F1 interface, and control information and / or user data are communicated between the CU218 and the DU219.

[0084] In a 5G communication system, the Unified Data Management (UDM) function and Policy Control Function (PCF) described in Non-Patent Document 21 (3GPP TS23.501) may be included. The UDM and / or PCF may be included in the 5GC unit 214 in Figure 3.

[0085] In a 5G communication system, a Location Management Function (LMF) as described in Non-Patent Document 24 (3GPP TS38.305) may be provided. The LMF may be connected to a base station via an AMF, as disclosed in Non-Patent Document 25 (3GPP TS23.273).

[0086] In a 5G communication system, a Non-3GPP Interworking Function (N3IWF) described in Non-Patent Document 21 (3GPP TS23.501) may be included. In non-3GPP access between the UE and the N3IWF, the Access Network (AN) may be terminated between the UE and the UE.

[0087] Figure 4 shows the configuration of a DC with eNBs and gNBs connected to the EPC. In Figure 4, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 4, eNB223-1 acts as the master base station, and gNB224-2 acts as the secondary base station (this DC configuration is sometimes referred to as EN-DC). Figure 4 shows an example where the U-Plane connection between the MME unit 204 and gNB224-2 is made via eNB223-1, but it may also be made directly between the MME unit 204 and gNB224-2.

[0088] Figure 5 shows the configuration of a DC with gNBs connected to the NG core. In Figure 5, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 5, gNB224-1 acts as the master base station, and gNB224-2 acts as the secondary base station (this DC configuration is sometimes referred to as NR-DC). Figure 5 shows an example where the U-Plane connection between 5GC unit 214 and gNB224-2 is made via gNB224-1, but it may also be made directly between 5GC unit 214 and gNB224-2.

[0089] Figure 6 shows the configuration of a DC with eNBs and gNBs connected to the NG core. In Figure 6, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 6, eNB226-1 acts as the master base station, and gNB224-2 acts as the secondary base station (this DC configuration is sometimes referred to as NG-EN-DC). Figure 6 shows an example where the U-Plane connection between 5GC unit 214 and gNB224-2 is made via eNB226-1, but it may also be made directly between 5GC unit 214 and gNB224-2.

[0090] Figure 7 shows another configuration of a DC with eNBs and gNBs connected to the NG core. In Figure 7, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In Figure 7, gNB224-1 acts as the master base station, and eNB226-2 acts as the secondary base station (this DC configuration is sometimes referred to as NE-DC). Figure 7 shows an example where the U-Plane connection between 5GC unit 214 and eNB226-2 is made via gNB224-1, but it may also be made directly between 5GC unit 214 and eNB226-2.

[0091] Figure 8 is a block diagram showing the configuration of the mobile terminal 202 shown in Figure 2. The transmission process of the mobile terminal 202 shown in Figure 8 will now be explained. First, control data from the protocol processing unit 301 and user data from the application unit 302 are stored in the transmission data buffer unit 303. The data stored in the transmission data buffer unit 303 is passed to the encoder unit 304, where encoding processing such as error correction is performed. There may be data that is output directly from the transmission data buffer unit 303 to the modulation unit 305 without undergoing encoding processing. The data encoded by the encoder unit 304 is then modulated in the modulation unit 305. Precoding in MIMO may be performed in the modulation unit 305. The modulated data is converted into a baseband signal, then output to the frequency conversion unit 306, where it is converted to a wireless transmission frequency. After that, the transmission signal is sent from antennas 307-1 to 307-4 to the base station 203. Figure 8 illustrates the case where there are four antennas, but the number of antennas is not limited to four.

[0092] Furthermore, the reception processing of the mobile terminal 202 is performed as follows: A radio signal from the base station 203 is received by antennas 307-1 to 307-4. The received signal is converted from the radio reception frequency to a baseband signal by the frequency conversion unit 306, and demodulation processing is performed by the demodulation unit 308. Weight calculation and multiplication processing may also be performed in the demodulation unit 308. The demodulated data is passed to the decoder unit 309, where decoding processing such as error correction is performed. Of the decoded data, the control data is passed to the protocol processing unit 301, and the user data is passed to the application unit 302. The series of processes of the mobile terminal 202 are controlled by the control unit 310. Therefore, although the control unit 310 is omitted in Figure 8, it is connected to each of the units 301 to 309. The control unit 310 is realized by a processing circuit that includes, for example, a processor and memory. That is, the control unit 310 is realized by the processor executing a program that describes the series of processes of the mobile terminal 202. A program describing a series of processes for the mobile terminal 202 is stored in memory. Examples of memory include non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), and flash memory. The control unit 310 may be implemented using a dedicated processing circuit such as an FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), or DSP (Digital Signal Processor). In Figure 8, the number of antennas used by the mobile terminal 202 for transmission and the number of antennas used for reception may be the same or different.

[0093] Figure 9 is a block diagram showing the configuration of the base station 203 shown in Figure 2. The transmission process of the base station 203 shown in Figure 9 will now be explained. The EPC communication unit 401 transmits and receives data between the base station 203 and the EPC (MME unit 204, etc.). The 5GC communication unit 412 transmits and receives data between the base station 203 and the 5GC (5GC unit 214, etc.). The other base station communication unit 402 transmits and receives data with other base stations. The EPC communication unit 401, the 5GC communication unit 412, and the other base station communication unit 402 each exchange information with the protocol processing unit 403. Control data from the protocol processing unit 403, as well as user data and control data from the EPC communication unit 401, the 5GC communication unit 412, and the other base station communication unit 402, are stored in the transmission data buffer unit 404.

[0094] The data stored in the transmission data buffer unit 404 is passed to the encoder unit 405, where it undergoes encoding processing such as error correction. Some data may be output directly from the transmission data buffer unit 404 to the modulation unit 406 without undergoing encoding processing. The encoded data is then modulated in the modulation unit 406. Precoding in MIMO may be performed in the modulation unit 406. The modulated data is converted to a baseband signal, then output to the frequency conversion unit 407, where it is converted to a wireless transmission frequency. Subsequently, the transmission signal is sent from antennas 408-1 to 408-4 to one or more mobile terminals 202. Figure 9 illustrates the case with four antennas, but the number of antennas is not limited to four.

[0095] Furthermore, the reception processing of the base station 203 is performed as follows: A radio signal from one or more mobile terminals 202 is received by the antenna 408. The received signal is converted from the radio reception frequency to a baseband signal by the frequency conversion unit 407, and demodulation processing is performed by the demodulation unit 409. The demodulated data is passed to the decoder unit 410, where decoding processing such as error correction is performed. Of the decoded data, the control data is passed to the protocol processing unit 403, the 5GC communication unit 412, the EPC communication unit 401, or the other base station communication unit 402, and the user data is passed to the 5GC communication unit 412, the EPC communication unit 401, or the other base station communication unit 402. The series of processes of the base station 203 are controlled by the control unit 411. Therefore, although the control unit 411 is omitted in Figure 9, it is connected to each of the units 401-410 and 412. The control unit 411, like the control unit 310 of the mobile terminal 202 described above, is implemented as a processing circuit that includes a processor and memory, or as a dedicated processing circuit such as an FPGA, ASIC, or DSP. In Figure 9, the number of antennas used by the base station 203 for transmission and the number of antennas used for reception may be the same or different.

[0096] Figure 9 is a block diagram showing the configuration of base station 203, but base station 213 may have a similar configuration. Also, in Figures 8 and 9, the number of antennas on mobile terminal 202 and base station 203 may be the same or different.

[0097] Figure 10 is a block diagram showing the configuration of the MME. Figure 10 shows the configuration of the MME204a included in the MME unit 204 shown in Figure 2 above. The PDN GW communication unit 501 transmits and receives data between the MME204a and the PDN GW (Packet Data Network Gateway). The base station communication unit 502 transmits and receives data between the MME204a and the base station 203 via the S1 interface. If the data received from the PDN GW is user data, the user data is passed from the PDN GW communication unit 501 to the base station communication unit 502 via the user-plane communication unit 503 and transmitted to one or more base stations 203. If the data received from the base station 203 is user data, the user data is passed from the base station communication unit 502 to the PDN GW communication unit 501 via the user-plane communication unit 503 and transmitted to the PDN GW.

[0098] If the data received from the PDN GW is control data, the control data is passed from the PDN GW communication unit 501 to the control plane control unit 505. If the data received from the base station 203 is control data, the control data is passed from the base station communication unit 502 to the control plane control unit 505.

[0099] The HeNBGW communication unit 504 transmits and receives data between the MME204a and the HeNB GW (Home-eNB Gateway). The control data received by the HeNBGW communication unit 504 from the HeNB GW is passed to the control plane control unit 505. The HeNBGW communication unit 504 transmits the control data input from the control plane control unit 505 to the HeNB GW.

[0100] The control plane control unit 505 includes the NAS security unit 505-1, the SAE bearer control unit 505-2, and the idle state mobility management unit 505-3, and performs all processing for the control plane (hereinafter sometimes referred to as C-Plane). The NAS security unit 505-1 performs security for NAS (Non-Access Stratum) messages, etc. The SAE bearer control unit 505-2 performs management of SAE (System Architecture Evolution) bearers, etc. The idle state mobility management unit 505-3 performs mobility management in the standby state (also referred to as LTE-IDLE state or simply idle), generation and control of paging signals in the standby state, addition, deletion, updating, searching, and tracking area list management for one or more mobile terminals 202 under its umbrella.

[0101] The MME204a distributes paging signals to one or more base stations 203. The MME204a also performs mobility control in the idle state. The MME204a manages the tracking area list when the mobile terminal 202 is in the idle state and when it is in the active state. The MME204a initiates the paging protocol by sending a paging message to cells belonging to the tracking area where the mobile terminal 202 is registered. The management of the CSG, CSG ID, and whitelist of the eNB207 connected to the MME204a may be performed by the idle state mobility management unit 505-3.

[0102] The series of processes of the MME204a are controlled by the control unit 506. Therefore, although the control unit 506 is omitted in Figure 10, it is connected to each of the units 501 to 505. The control unit 506 is implemented as a processing circuit that includes a processor and memory, similar to the control unit 310 of the mobile terminal 202 described above, or as a dedicated processing circuit such as an FPGA, ASIC, or DSP.

[0103] Figure 11 is a block diagram showing the configuration of the 5GC unit. Figure 11 shows the configuration of the 5GC unit 214 shown in Figure 3. Figure 11 shows the case where the 5GC unit 214 shown in Figure 5 includes the configurations of AMF, SMF, and UPF. The Data Network communication unit 521 transmits and receives data between the 5GC unit 214 and the Data Network. The base station communication unit 522 transmits and receives data via the S1 interface between the 5GC unit 214 and the base station 203, and / or the NG interface between the 5GC unit 214 and the base station 213. If the data received from the Data Network is user data, the user data is passed from the Data Network communication unit 521 to the base station communication unit 522 via the user-plane communication unit 523, and transmitted to one or more base stations 203 and / or base station 213. If the data received from base station 203 and / or base station 213 is user data, the user data is passed from base station communication unit 522 to Data Network communication unit 521 via user plane communication unit 523 and transmitted to the Data Network.

[0104] If the data received from the Data Network is control data, the control data is passed from the Data Network communication unit 521 to the session management unit 527 via the user-plane communication unit 523. The session management unit 527 passes the control data to the control-plane control unit 525. If the data received from base station 203 and / or base station 213 is control data, the control data is passed from base station communication unit 522 to the control-plane control unit 525. The control-plane control unit 525 passes the control data to the session management unit 527.

[0105] The control plane control unit 525 includes the NAS security unit 525-1, the PDU session control unit 525-2, and the idle state mobility management unit 525-3, and performs all processing for the control plane (hereinafter sometimes referred to as C-Plane). The NAS security unit 525-1 performs security for NAS (Non-Access Stratum) messages, etc. The PDU session control unit 525-2 manages PDU sessions between the mobile terminal 202 and the 5GC unit 214, etc. The idle state mobility management unit 525-3 performs mobility management in the standby state (also referred to as RRC_IDLE state or simply idle), generation and control of paging signals in the standby state, addition, deletion, updating, searching, and tracking area list management for one or more mobile terminals 202 under its umbrella.

[0106] The series of processes in the 5GC unit 214 are controlled by the control unit 526. Therefore, although the control unit 526 is omitted in Figure 11, it is connected to each of the units 521-523, 525, and 527. The control unit 526 is implemented as a processing circuit that includes a processor and memory, similar to the control unit 310 of the mobile terminal 202 described above, or as a dedicated processing circuit such as an FPGA, ASIC, or DSP.

[0107] Next, an example of a cell search method in a communication system is shown. Figure 12 is a flowchart illustrating the process from cell search to standby operation performed by a communication terminal (UE) in an LTE communication system. When the communication terminal starts a cell search, in step ST601, it synchronizes the slot timing and frame timing using the first synchronization signal (P-SS) and the second synchronization signal (S-SS) transmitted from the surrounding base station.

[0108] P-SS and S-SS together are called the Synchronization Signal (SS). Each PCI assigned to a cell has a synchronization code that corresponds one-to-one with that PCI. 504 different PCI combinations are being considered. The communication terminal uses these 504 PCI combinations to synchronize and also detects (identifies) the PCI of the synchronized cell.

[0109] The communication terminal then detects the cell-specific reference signal (CRS), which is a reference signal (RS) transmitted from the base station to each cell, in step ST602 for the next synchronized cell, and measures the Reference Signal Received Power (RSRP). The reference signal (RS) uses a code that corresponds one-to-one with the PCI. By correlating with this code, it is possible to isolate it from other cells. By deriving the code for the RS of the cell from the PCI identified in step ST601, it becomes possible to detect the RS and measure the received power of the RS.

[0110] Next, in step ST603, the communication terminal selects the cell with the best RS reception quality from among the one or more cells detected up to step ST602, for example, the cell with the highest RS reception power, i.e., the best cell.

[0111] Next, in step ST604, the communication terminal receives the PBCH of the best cell and obtains the BCCH, which is broadcast information. The BCCH on the PBCH is mapped to the MIB (Master Information Block), which contains cell configuration information. Therefore, by receiving the PBCH and obtaining the BCCH, the MIB can be obtained. MIB information includes, for example, the DL (downlink) system bandwidth (also called transmission bandwidth configuration: dl-bandwidth), the number of transmitting antennas, and the SFN (System Frame Number).

[0112] Next, in step ST605, the communication terminal receives the DL-SCH of the cell based on the cell configuration information of the MIB and obtains SIB (System Information Block) 1 from the broadcast information BCCH. SIB1 contains information about accessing the cell, information about cell selection, and scheduling information for other SIBs (SIBk; an integer k ≥ 2). SIB1 also contains the Tracking Area Code (TAC).

[0113] Next, in step ST606, the communication terminal compares the TAC of the SIB1 received in step ST605 with the TAC portion of the Tracking Area Identity (TAI) in the Tracking Area List already held by the communication terminal. The Tracking Area List is also called the TAI list. TAI is identification information for identifying a tracking area and consists of MCC (Mobile Country Code), MNC (Mobile Network Code), and TAC (Tracking Area Code). MCC is the country code. MNC is the network code. TAC is the code number of the tracking area.

[0114] If, as a result of the comparison in step ST606, the TAC received in step ST605 is the same as a TAC included in the tracking area list, the communication terminal enters a waiting state in that cell. If, after comparison, the TAC received in step ST605 is not included in the tracking area list, the communication terminal requests a change in the tracking area through that cell to the Core Network (EPC), which includes the MME, etc., in order to perform a Tracking Area Update (TAU).

[0115] In the example shown in Figure 12, an example of the operation from cell search to standby in the LTE system is shown. However, in the NR system, in step ST603, the best beam may be selected in addition to the best cell. Also in the NR system, in step ST604, beam information, such as a beam identifier, may be obtained. Also in the NR system, in step ST604, scheduling information for the Remaining Minimum SI (RMSI) may be obtained. In the NR system, in step ST605, the RMSI may be received.

[0116] The devices constituting the core network (sometimes referred to as "core network devices") update the tracking area list based on the identification number (UE-ID, etc.) of the communication terminal sent from the communication terminal along with the TAU request signal. The core network devices send the updated tracking area list to the communication terminal. The communication terminal rewrites (updates) its TAC list based on the received tracking area list. After that, the communication terminal enters a waiting state in that cell.

[0117] The proliferation of smartphones and tablet devices has led to an explosive increase in cellular wireless communication traffic, raising concerns about a shortage of wireless resources worldwide. To address this, efforts are being made to improve frequency utilization efficiency by reducing the number of cells and promoting spatial separation.

[0118] In conventional cell configurations, cells composed of eNBs have relatively wide coverage. Traditionally, cells are configured to cover a certain area through the relatively wide coverage of multiple cells composed of multiple eNBs.

[0119] When subdivided into smaller cells, the cells composed of eNBs have narrower coverage than cells composed of conventional eNBs. Therefore, as before, a larger number of subdivided eNBs are needed to cover a given area compared to conventional eNBs.

[0120] In the following explanation, cells with relatively high coverage, such as those composed of conventional eNBs, will be referred to as "macrocells," and the eNBs that make up macrocells will be referred to as "macro eNBs." Similarly, cells with relatively low coverage, such as those that have been resized into smaller cells, will be referred to as "small cells," and the eNBs that make up small cells will be referred to as "small eNBs."

[0121] Macro eNB may be, for example, a "Wide Area Base Station" as described in Non-Patent Document 7.

[0122] A small eNB may be, for example, a low-power node, a local area node, or a hotspot. Alternatively, a small eNB may be a pico eNB constituting a picocell, a femto eNB constituting a femtocell, a HeNB, an RRH (Remote Radio Head), an RRU (Remote Radio Unit), an RRE (Remote Radio Equipment), or an RN (Relay Node). Furthermore, a small eNB may be a "Local Area Base Station" or "Home Base Station" as described in Non-Patent Document 7.

[0123] Figure 13 shows an example of a cell configuration in NR. In an NR cell, a narrow beam is formed and transmitted by changing its direction. In the example shown in Figure 13, base station 750 uses beam 751-1 to transmit and receive with a mobile terminal at a certain time. At other times, base station 750 uses beam 751-2 to transmit and receive with a mobile terminal. Similarly, base station 750 uses one or more of beams 751-3 to 751-8 to transmit and receive with a mobile terminal. In this way, base station 750 configures a wide-area cell.

[0124] Figure 13 shows an example where the base station 750 uses eight beams, but the number of beams may be different from eight. Also, in the example shown in Figure 13, the base station 750 uses one beam simultaneously, but it may use multiple beams.

[0125] In 3GPP, Side Link (SL) is supported for D2D (Device to Device) and V2V (Vehicle to Vehicle) communication (see Non-Patent Documents 1 and 16). SL is defined by the PC5 interface.

[0126] The physical channels used in SL (see Non-Patent Document 1) are described below. The Physical Sidelink Broadcast Channel (PSBCH) carries system and synchronization-related information and is transmitted from the UE.

[0127] The Physical Sidelink Discovery Channel (PSDCH) carries sidelink discovery messages from the UE (Union Engine).

[0128] The Physical Sidelink Control Channel (PSCCH) carries control information from the UE for sidelink communication and V2X sidelink communication.

[0129] The Physical Sidelink Shared Channel (PSSCH) carries data from the UE for sidelink communication and V2X sidelink communication.

[0130] The Physical Sidelink Feedback Channel (PSFCH) carries HARQ feedback over the sidelink from the UE that received the PSSCH transmission to the UE that transmitted the PSSCH.

[0131] The transport channels used in SL (see Non-Patent Document 1) are described below. The Sidelink broadcast channel (SL-BCH) has a predetermined transport format and is mapped to the physical channel PSBCH.

[0132] The Sidelink Discovery Channel (SL-DCH) has periodic broadcast transmissions in a fixed size and predetermined format. The SL-DCH supports both UE autonomous resource selection and resource allocation scheduled by the eNB. UE autonomous resource selection carries a risk of collisions, while there are no collisions when the UE allocates resources individually via the eNB. The SL-DCH also supports HARQ combining but not HARQ feedback. The SL-DCH is mapped to the physical channel PSDCH.

[0133] Sidelink shared channels (SL-SCH) support broadcast transmission. SL-SCH supports both UE autonomous resource selection and resource allocation scheduled by the eNB. UE autonomous resource selection carries a risk of collisions, while individual resource allocation by the eNB avoids collisions. SL-SCH also supports HARQ combining but not HARQ feedback. Furthermore, SL-SCH supports dynamic link adaptation by changing transmit power, modulation, and coding. SL-SCH is mapped to the physical channel PSSCH.

[0134] The logic channels used in SL (see Non-Patent Document 1) are described below. The Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel used to broadcast sidelink system information from one UE to another. The SBCCH is mapped to the transport channel SL-BCH.

[0135] A Sidelink Traffic Channel (STCH) is a one-to-many sidelink traffic channel for transmitting user information from one UE to another. STCH is used only by UEs with sidelink communication capabilities and UEs with V2X sidelink communication capabilities. One-to-one communication between two UEs with sidelink communication capabilities is also achieved via STCH. STCH is mapped to the transport channel SL-SCH.

[0136] The Sidelink Control Channel (SCCH) is a sidelink control channel used to transmit control information from one UE to another. The SCCH is mapped to the transport channel SL-SCH.

[0137] 3GPP is considering supporting V2X communication in NR as well. The study of V2X communication in NR is progressing based on the LTE system and LTE-A system, but the following changes and additions have been made from the LTE system and LTE-A system.

[0138] In LTE, SL communication was limited to broadcast only. In NR, support for unicast and groupcast in addition to broadcast is being considered for SL communication (see Non-Patent Document 22 (3GPP TS23.287)).

[0139] Support for HARQ feedback (Ack / Nack) and CSI reporting is being considered for unicast and groupcast communications.

[0140] In SL communication, in addition to broadcast, support for unicast and groupcast is being considered, and therefore support for PC5-S signaling is being explored (see Non-Patent Document 22 (3GPP TS23.287)). For example, PC5-S signaling is implemented to establish a link for SL, i.e., PC5 communication. This link is implemented at the V2X layer and is also referred to as a Layer 2 link.

[0141] Furthermore, support for RRC signaling in SL communication is being considered (see Non-Patent Document 22 (3GPP TS23.287)). RRC signaling in SL communication is also referred to as PC5 RRC signaling. For example, it has been proposed to notify UEs of their capabilities between UEs performing PC5 communication, and to notify AS layer settings for V2X communication using PC5 communication.

[0142] In multicast communication using NR, both PTM (Point to Multipoint) and PTP (Point to Point) may be used. A common PDCP entity may be used in both PTM and PTP. PTM and PTP may have different legs (RLC, combinations of logical channels). In multicast communication, PTM legs and PTP legs may be used while being dynamically switched between them.

[0143] 5G base stations can support Integrated Access and Backhaul (IAB) (see Non-Patent Document 16 (TS38.300)). That is, multicast may be performed using a base station that supports IAB (hereinafter sometimes referred to as an IAB base station).

[0144] In multicast using an IAB configuration base station, an IAB node located along the path from the IAB donor CU (which is the CU of the base station acting as the IAB donor) to the UE may perform multicast transmission to the IAB node to which it connects in communication with the UE (hereinafter sometimes referred to as a child IAB node), or it may perform multicast transmission to the UE.

[0145] However, the detailed configuration method for multicast at IAB base stations has not been disclosed. Consequently, a problem arises in that multicast using IAB base stations cannot be implemented.

[0146] This first embodiment discloses a method for solving these problems.

[0147] To solve the aforementioned problems, in the communication system according to this embodiment, the IAB donor CU determines the multicast settings. The IAB donor CU notifies the IAB donor DU (the DU of a base station operating as an IAB donor) and / or the IAB node (a base station operating as an IAB node) of these settings. The IAB donor CU may perform these settings on the IAB donor DU and / or the IAB node in order of proximity to its own CU. For example, the IAB donor CU may perform the settings on the IAB donor DU, then on the child IAB node of the IAB donor DU, and then on the child IAB node of the child IAB node. The IAB donor CU may perform the settings on the IAB node directly connected to the UE, and then on the UE.

[0148] The IAB donor CU may perform the configuration for the IAB donor DU and / or IAB node using F1 signaling. This F1 signaling may be, for example, BAP (Backhaul Adaptation Protocol) mapping configuration signaling (see Non-Patent Document 35 (TS38.473)) or other signaling.

[0149] The configuration may include information regarding routing at the BAP layer. The IAB donor CU may include this information in the configuration. The configuration may be performed for each of the PTM and PTP legs. The BAP layer routing information may include information that identifies the routing, for example, a routing identifier; information regarding the BAP addresses of the IAB donor DU and / or IAB nodes (see Non-Patent Literature 35 (TS38.473)); information regarding the next hop destination, for example, the BAP address of a child IAB node; information regarding the BAP address of an IAB node that is directly connected to the UE receiving the multicast data; and information regarding the route from the IAB donor CU to the UE, for example, information regarding the route identifier. This allows, for example, the IAB donor DU and / or IAB node to smoothly route the multicast data to the UE.

[0150] The configuration may include multiple pieces of information regarding routing at the BAP layer. For example, it may include routing information for transmissions using PTM legs and routing information for transmissions using PTP legs. It may also include multiple pieces of information regarding routing for transmissions using PTP legs, or multiple pieces of information regarding routing for transmissions using PTM legs. The IAB node may switch the routing destination using information included in the BAP header, such as DESTINATION and / or Path ID information. This allows for dynamic changes to the routing destination at the IAB node, for example.

[0151] The configuration may include information about the area from which multicast can be transmitted. The IAB node may use this information to control the beam and / or transmit power so that the transmission range of multicast data is contained within that area. This prevents, for example, the transmission of multicast data outside the transmittable area.

[0152] The configuration may include information regarding the transmission method. This information may include information indicating the use of PTM legs or information indicating the use of PTP legs. This information may be provided for each child IAB node and / or UE receiving the transmission. The IAB donor DU and / or IAB node may use this information to determine which leg to use for transmission to the child IAB node and / or UE. This allows, for example, the IAB donor DU and / or IAB node to quickly determine which leg to use for the transmission.

[0153] There may be a predetermined mode for the transmission method from an IAB donor DU and / or IAB node to a child IAB node and / or UE. For example, there may be a mode in which PTM legs are used for transmission to both the child IAB node and the UE, or a mode in which PTM legs are used for transmission to the UE and PTP legs are used for transmission to the child IAB node, or a mode in which PTP legs are used for transmission to the UE and PTM legs are used for transmission to the child IAB node, or a mode in which PTP legs are used for transmission to both the child IAB node and the UE. Other examples include modes that allow the use of both PTP and PTM legs for the UE, modes that transmit to the UE using only PTP legs, modes that transmit to the UE using only PTM legs, modes that allow the use of both PTP and PTM legs for child IAB nodes, modes that transmit to child IAB nodes using only PTP legs, modes that transmit to child IAB nodes using only PTM legs, and combinations of the above, for example, each mode for transmission to the UE and each mode for transmission to child IAB nodes, may be used in combination. The mode may be configurable for each child IAB node and / or UE. The mode may be determined by the IAB donor CU and notified to the IAB donor DU and / or IAB node. The mode may be included in the above-mentioned configuration. The IAB donor DU and / or IAB node may use information about the mode to determine which leg to use for transmission to the child IAB node and / or UE. This allows, for example, an IAB donor DU and / or IAB node to quickly determine which leg to use for the transmission, thereby reducing the processing load on the transmission from the IAB donor DU and / or IAB node.

[0154] In routing using IAB nodes, multicast data received using a PTM leg may be transmitted using a PTP leg, multicast data received using a PTP leg may be transmitted using a PTM leg, multicast data received using a PTM leg may be transmitted using a PTM leg, or multicast data received using a PTP leg may be transmitted using a PTP leg. This allows for improved flexibility in communication systems, for example.

[0155] BAP layer routing may be determined using information about the area from which multicast can be transmitted. For example, the IAB node that performs the multicast routing may be selected from among the IAB nodes whose transmission range is included in that area. This makes it possible, for example, to prevent the transmission of multicast data outside the transmission area.

[0156] The core network device may determine information about the area where multicast can be transmitted. The core network device may notify the IAB donor CU of this information. Alternatively, the core network device may notify the IAB donor CU of information about the IAB nodes belonging to that area. The IAB donor CU may use the aforementioned information to determine which IAB nodes to route. This allows the IAB donor CU to appropriately select IAB nodes within the area where multicast can be transmitted.

[0157] An IAB donor DU and / or IAB node may determine an identifier to assign to a child IAB node and / or UE. This identifier may be, for example, G-RNTI and / or SC-RNTI (see Non-Patent Document 34 (TS36.321)) or C-RNTI. The IAB donor DU and / or IAB node may notify the IAB donor CU of this identifier. This notification may be made using F1 signaling, for example, UL RRC MESSAGE TRANSFER signaling (see Non-Patent Document 35 (TS38.473)).

[0158] The IAB donor CU may notify the IAB node and / or UE of the multicast configuration. This notification may be made via the IAB donor DU and / or parent IAB node (the IAB node to which the IAB node is connected in communication between the IAB node and the IAB donor CU, hereinafter the same). This notification to the IAB donor DU and / or parent IAB node may be made using F1 signaling, for example, DL RRC MESSAGE TRANSFER (see Non-Patent Document 35 (TS38.473)). This notification from the IAB donor DU and / or parent IAB node to the IAB node and / or UE may be made using RRC signaling, for example, RRC Reconfiguration signaling. The IAB node and / or UE may use this notification to perform multicast receiving operations.

[0159] The notification from the IAB donor CU to the IAB node and / or UE may include information about the PTM leg, information about the PTP leg, information about the aforementioned identifier, information about the BAP address, information about the RLC configuration, information about the MAC configuration, information about the PHY configuration, and information about the logical channel, for example, information used to identify the logical channel. The BAP address may include information about the BAP address of the IAB donor DU and / or the IAB node, information about the BAP address of the next hop, for example, a child IAB node, and information about the BAP address of the IAB node that is directly connected to the UE receiving the multicast data. The aforementioned information may be included as information about the PTM leg and the PTP leg, respectively.

[0160] A BAP address used for multicast (hereinafter sometimes referred to as a multicast BAP address) may be provided. A multicast BAP address may be provided for each multicast service or content. This allows, for example, each device in the communication system to quickly recognize the multicast service or content.

[0161] As another example, a multicast BAP address may be assigned to each combination of IAB nodes that will be the destination of the multicast. This allows, for example, each device in the communication system to quickly recognize the IAB nodes that will be the destination of the multicast.

[0162] A mapping may be established between a multicast BAP address and an IAB node. There may be one or more IAB nodes. The mapping may be determined by the IAB donor CU. The IAB donor CU may notify the IAB donor DU and / or IAB node of information regarding the mapping. This notification may use, for example, BAP mapping configuration signaling or DL ​​RRC MESSAGE TRANSFER signaling. The IAB donor DU and / or IAB node may use the notification to identify child IAB nodes that are destinations for multicast transmissions. The IAB donor DU and / or IAB node may perform multicast transmissions to the child IAB nodes included in the notification. This eliminates the need for the IAB donor DU and / or IAB node to perform multicast transmissions to child IAB nodes not included in the notification, thereby improving the efficiency of the communication system.

[0163] As another example, multicast BAP addresses may be set within a predetermined range of possible values ​​for BAP addresses. For example, a range of BAP addresses where the first four bits are all '1' may be set as multicast BAP addresses. This allows, for example, each device in a communication system to quickly recognize whether a BAP address is for multicast or not.

[0164] The IAB donor CU may configure the multicast BAP address as the next hop destination, for example, the BAP address of a child IAB node. This configuration may be included, for example, in the BAP mapping signaling, in the DL RRC MESSAGE TRANSFER signaling, or in the RRC reconfiguration signaling. This reduces the amount of signaling, for example, from the IAB donor CU to the IAB donor DU and / or IAB nodes, and from the IAB donor DU and / or IAB nodes to child IAB nodes and / or UEs.

[0165] The multicast BAP address may be included in the BAP layer header (see Non-Patent Document 36 (TS38.340)). This allows, for example, multicast data transmission to multiple child IAB nodes to be performed using a single BAP PDU (Protocol Data Unit), thereby reducing the load on backhaul communication.

[0166] A mapping may be established between the multicast BAP address and the aforementioned G-RNTI and / or SC-RNTI. For example, an IAB donor CU may determine the multicast BAP address using the aforementioned G-RNTI and / or SC-RNTI. For example, an IAB donor DU and / or IAB node may send data to a child IAB node and / or UE that has been assigned to the aforementioned G-RNTI, where the next hop's BAP address is the multicast BAP address. This can improve the efficiency of the communication system, for example.

[0167] An IAB node may use the DESTINATION information contained in the BAP header to decide whether or not to perform routing. For example, if the BAP address contained in DESTINATION is not assigned to the node itself, routing may be performed. The BAP address contained in DESTINATION may be a multicast BAP address. An IAB node that performs routing may use the Path ID contained in the BAP header to determine the next IAB node to reach.

[0168] A path ID may be provided for multicast. A multicast path ID may be provided for each multicast service or content. A mapping may be established between a multicast path ID and one or more BAP addresses. The multicast BAP address may include the multicast BAP address. The IAB donor CU may use the multicast path ID in multicast configuration to the IAB donor DU and / or IAB node. This can, for example, reduce the number of path IDs used in the IAB donor CU and avoid the complexity of managing path IDs.

[0169] Different path ID values ​​may be assigned to routing transmitted using PTM legs and routing transmitted using PTP legs. This can, for example, avoid the complexity of managing routing paths in a communication system.

[0170] As another example, the same path ID value may be set for routing transmitted using PTM legs and routing transmitted using PTP legs. This can, for example, reduce the number of path IDs used, and as a result, increase the number of UEs that can accommodate multicast.

[0171] Figures 14 and 15 show the multicast configuration sequence at an IAB base station. Figure 14 shows the first half of the sequence, and Figure 15 shows the second half. Specifically, multicast configuration at an IAB base station involves first executing steps ST1510 to ST1528 shown in Figure 14, and then executing steps ST1532 to ST1594 shown in Figure 15. In the examples shown in Figures 14 and 15, the UE is connected to the IAB donor CU via IAB node #2, IAB node #1, and IAB donor DU. In the examples shown in Figures 14 and 15, it is assumed that the UE has already obtained multicast information.

[0172] In step ST1510 shown in Figure 14, the UE makes a PDU session modification request to the AMF. This request may be made using NAS signaling. The request may include information about the multicast that the UE wants to receive. In step ST1512, the AMF notifies the SMF that a PDU session modification request has been made. This notification may be made, for example, using the Nsmf_PDUSession_UpdateSMContext service operation (see Non-Patent Document 37 (TS23.502)). The notification may include information about the multicast that the UE wants to receive. In step ST1514, the SMF checks whether the UE can receive the multicast. In step ST1516, the SMF queries the Unified Data Repository (UDR) (see Non-Patent Document 21 (TS23.501)) for information about the multicast and retrieves the information from the UDR. In step ST1518, the SMF requests multicast / broadcast SMF (MB-SMF) (see Non-Patent Document 28 (TR23.757)) for multicast QoS information. In step ST1520, the MB-SMF notifies the SMF of its response to the request. This response may include multicast QoS information.

[0173] In step ST1522 shown in Figure 14, the SMF requests the AMF to send a message to the base station. This request may be made using the Namf_Communication_N1N2MessageTransfer service operation (see Non-Patent Document 37 (TS23.502)). This request may include a request for the creation of a multicast context at the base station. In step ST1524, the AMF requests the IAB donor CU to modify the PDU session. This request may, for example, use PDU Session Resource Modify Request signaling (see Non-Patent Document 38 (TS38.413)). This request may include information about the multicast session. The IAB donor CU may use this information to obtain information about the multicast session.

[0174] In step ST1526 shown in Figure 14, the IAB donor CU notifies IAB node #2 of a PDU session change request. The request may include information about the multicast session. This notification may also be made via the IAB donor DU, IAB node #1. This notification may be made using F1 signaling, for example, DL RRC MESSAGE TRANSFER. In step ST1528, IAB node #2 notifies the UE of the PDU session change request. The UE may use the information from step ST1528 to obtain information about the multicast session. The UE may change the information about the PDU session.

[0175] In steps ST1532 to ST1562 shown in Figure 15, settings for multicast transmission are configured between the IAB base station and the UE.

[0176] In step ST1532 shown in Figure 15, the IAB donor CU configures routing information for the IAB donor DU. The IAB donor CU may determine the information necessary for this configuration upon receiving the request in step ST1524. For example, the IAB donor CU may use the information contained in the request received in step ST1524 to determine the PDU session related to multicast and the IAB node to be used for routing. The routing information may include information about the IAB donor DU's BAP address, route information, such as information about the IAB node directly connected to the UE, information about the BAP address of the next hop, and information about the identifier of the RLC channel to be used. F1 signaling, such as BAP MAPPING CONFIGURATION signaling, may be used for the configuration in step ST1532. In step ST1534, the IAB donor DU notifies the IAB donor CU of its response to step ST1532. In the example shown in Figure 15, an acknowledgment is notified. The notification in step ST1534 may use F1 signaling, such as the BAP MAPPING CONFIGURATION ACKNOWLEDGEMENT signaling. In step ST1536, the IAB donor DU notifies the IAB donor CU of an identifier to be assigned to the child IAB node, IAB node #1 in the example shown in Figure 15. This identifier may be C-RNTI, G-RNTI, SC-RNTI, or a combination of the above. The notification may include information about the RRC settings that the IAB donor DU will use for communication with IAB node #1. The IAB donor DU may make the notification in step ST1536 upon receiving step ST1532. This notification may use F1 signaling, such as the UL RRC MESSAGE TRANSFER.

[0177] In step ST1538 shown in Figure 15, the IAB donor CU notifies the IAB donor DU of the RRC settings to be used for multicast communication with IAB node #1. This notification may be made using F1 signaling, for example, DL RRC MESSAGE TRANSFER signaling. In step ST1540, the IAB donor DU configures IAB node #1 for multicast. This configuration may include settings for PTM legs and settings for PTP legs. This configuration may include, for example, RRC reconfiguration signaling. Step ST1540 may include information about the identifier of IAB node #1, for example, C-RNTI, G-RNTI, and / or SC-RNTI, information about the BAP address, information about the RLC settings, information about the MAC settings, information about the PHY settings, and information about the logical channel, for example, information used to identify the logical channel. The BAP address may include information about the BAP address of IAB node #1, information about the BAP address of the next hop, for example, IAB node #2, or information about the BAP address of the IAB node directly connected to the UE receiving multicast data, for example, information about the BAP address of IAB node #2. The aforementioned information may also be included as information for the PTM leg and the PTP leg, respectively. In step ST1542, IAB node #1 notifies IAB donor DU that the multicast configuration is complete. This notification may use, for example, RRCReconfigurationComplete signaling. In step ST1443, IAB donor DU notifies IAB donor CU of the RRC reconfiguration completion of IAB node #1. This notification may use F1 signaling, for example, UL RRC MESSAGE TRANSFER signaling. The IAB donor CU may recognize that multicast configuration for IAB node #1 has been completed, triggered by ST1543.

[0178] In step ST1544 shown in Figure 15, the IAB donor CU configures routing information for IAB node #1. The routing information may include information about the BAP address of IAB node #1, route information, such as information about IAB nodes directly connected to the UE, information about the BAP address of the next hop, or information about the identifier of the RLC channel to be used. F1 signaling, such as BAP MAPPING CONFIGURATION signaling, may be used for the configuration in step ST1544. In step ST1546, IAB node #1 notifies the IAB donor CU of its response to step ST1544. In the example shown in Figure 15, an acknowledgment is notified. F1 signaling, such as BAP MAPPING CONFIGURATION ACKNOWLEDGEMENT signaling, may be used for the notification in step ST1546. In step ST1548, IAB node #1 notifies the IAB donor CU of an identifier to be assigned to the child IAB node, IAB donor #2 in the example shown in Figure 15. This identifier may be C-RNTI, G-RNTI, SC-RNTI, or a combination of the above. The notification may include information regarding the RRC settings used by IAB node #1 for communication with IAB node #2. IAB node #1 may issue the notification in step ST1548 upon receiving step ST1540, upon receiving step ST1544, or upon receiving both step ST1540 and step ST1544. F1 signaling, such as UL RRC MESSAGE TRANSFER, may be used for this notification.

[0179] In step ST1550 shown in Figure 15, the IAB donor CU notifies IAB node #1 of the RRC settings to be used for multicast communication with IAB node #2. This notification may be made using F1 signaling, for example, DL RRC MESSAGE TRANSFER signaling. In step ST1552, IAB node #1 configures IAB node #2 for multicast. This configuration may include settings for PTM legs or settings for PTP legs. This configuration may include, for example, RRC reconfiguration signaling. Step ST1552 may include information about the identifier of IAB node #2, for example, C-RNTI, G-RNTI, and / or SC-RNTI, information about the BAP address, information about RLC settings, information about MAC settings, information about PHY settings, and information about logical channels, for example, information used to identify logical channels. The BAP address may include information about the BAP address of IAB node #2, information about the BAP address of the next hop, or information about the BAP address of the IAB node directly connected to the UE receiving multicast data. The aforementioned information may also be included as information for the PTM leg and the PTP leg, respectively. In step ST1554, IAB node #2 notifies IAB node #1 that the multicast configuration is complete. This notification may use, for example, RRC reconfiguration completion signaling. In step ST1555, IAB node #1 notifies the IAB donor CU of the completion of RRC reconfiguration for IAB node #2. This notification may use F1 signaling, for example, UL RRC MESSAGE TRANSFER signaling. The IAB donor CU may recognize that the multicast configuration for IAB node #2 is complete as a result of step ST1555.

[0180] In step ST1556 shown in Figure 15, IAB node #2 notifies the IAB donor CU of an identifier to be assigned to the UE. This identifier may be C-RNTI, G-RNTI, SC-RNTI, or a combination of the above. The notification may include information regarding the RRC settings that IAB node #2 will use for communication with the UE. IAB node #2 may perform the notification in step ST1556 upon receiving step ST1554. F1 signaling, such as UL RRC MESSAGE TRANSFER, may be used for this notification.

[0181] In step ST1558 shown in Figure 15, the IAB donor CU notifies IAB node #2 of the RRC settings to be used for multicast communication with the UE. This notification may use F1 signaling, for example, DL RRC MESSAGE TRANSFER signaling. In step ST1560, IAB node #2 configures the UE for multicast. This configuration may include settings for the PTM leg and settings for the PTP leg. This configuration may include, for example, RRC reconfiguration signaling. Step ST1560 may include information about the UE identifier, for example, C-RNTI, G-RNTI, and / or SC-RNTI, information about the RLC settings, information about the MAC settings, information about the PHY settings, and information about the logical channel, for example, information used to identify the logical channel. The aforementioned information may be included as information about the PTM leg and the PTP leg, respectively. In step ST1562, the UE notifies IAB node #2 that the multicast configuration is complete. This notification may include, for example, signaling for completion of RRC reconfiguration. In step ST1563, IAB node #2 notifies IAB donor CU of the UE's RRC reconfiguration completion. This notification may include F1 signaling, for example, UL RRC MESSAGE TRANSFER signaling. The IAB donor CU may recognize that the multicast configuration for the UE is complete as a result of step ST1563.

[0182] In step ST1572 shown in Figure 15, the IAB donor CU requests multicast distribution from the AMF. This request may include information identifying the UE or information identifying the multicast. In step ST1574, the AMF requests multicast distribution from the MB-SMF. In step ST1576, a modification of session information related to multicast distribution is performed between the MB-SMF and the multicast / broadcast UPF (MB-UPF) (see Non-Patent Literature 28 (TR23.757)). In step ST1578, the MB-SMF notifies the AMF of its response to the multicast distribution request. In step ST1580, the AMF notifies the IAB donor CU of its response to the multicast distribution request.

[0183] In step ST1582 shown in Figure 15, the IAB donor CU notifies the AMF of the response to the change in session information related to multicast distribution. In step ST1584, the AMF notifies the SMF of the response to the change in session information. For example, the processing of Nsmf_PDUSession_UpdateSMContext (see Non-Patent Literature 37 (TS23.502)) may be used for this notification.

[0184] In step ST1586 shown in Figure 15, MB-UPF transmits multicast data to the IAB donor CU. In step ST1588, the IAB donor CU forwards the data to the IAB donor DU. In step ST1590, the IAB donor DU forwards the data to IAB node #1. In step ST1592, IAB node #1 forwards the data to IAB node #2. In step ST1594, IAB node #2 forwards the data to the UE. In steps ST1590 to ST1594, a PTP leg may be used, a PTM leg may be used, or both may be used.

[0185] In multicast transmission from an IAB base station, switching between PTM legs and PTP legs may occur. This switching may be determined by the IAB donor CU or by the IAB node directly connected to the UE. The IAB donor CU and / or the IAB node may make this determination using information about PDCP SNs (Sequence Numbers), for example, information about PDCP SNs for which delivery confirmation has been received by the UE. The IAB node may notify the IAB donor CU of the result of this determination. The IAB donor CU may use the result of the determination by its own CU and / or the IAB node to determine which leg to use in multicast.

[0186] Other examples of such switching include the decision being made by the IAB donor DU or by an IAB node along the path to the UE. The IAB donor DU and / or the IAB node may make the decision using information about RLC SNs, for example, information about RLC SNs for which delivery confirmation has been received by the UE. The IAB donor DU and / or the IAB node may notify the IAB donor CU of the result of the decision. The IAB donor CU may use the result of the decision made by its own CU and / or the IAB node to determine which leg to use in multicast.

[0187] Another example of such switching is that the UE may decide whether to switch. For example, the UE may make this decision using multicast reception status (e.g., PDCP SN, RLC SN). The UE may notify the base station of the request for the switch or notify it of information regarding multicast reception status. The UE may be able to autonomously send such notification to the base station. The notification may use a PDCP status report (see Non-Patent Document 39 (TS38.323)). The IAB donor CU may use the information received from the UE to perform the PTM / PTP switch.

[0188] As another example, the UE may use PRACH or RRC signaling for the notification. An IAB donor DU and / or IAB node communicating directly with the UE may forward the notification from the UE to the IAB donor CU. The IAB donor DU and / or IAB node may use F1 signaling for this forwarding. This allows, for example, the IAB donor DU and / or IAB node to notify the IAB donor CU of a PTM / PTP switching request from the UE. The IAB donor CU may use the notification forwarded from the IAB donor DU and / or IAB node to perform the PTM / PTP switching.

[0189] The aforementioned F1 signaling may include, for example, the UL RRC MESSAGE TRANSFER signaling (see Non-Patent Document 35 (TS38.473)), or a new signaling method may be used. The new signaling method may include, for example, information indicating that a PTM / PTP switching request has been made from the UE, information about the leg before switching, information about the leg after switching, information about the multicast reception status at the UE for the leg, or a combination of the above information. As an example of information regarding multicast reception status, information regarding the expiration of a timer used in the PDCP layer (e.g., t-reordering as described in Non-Patent Document 39) may be used, or information indicating that the number of missing PDCP SDUs (Service Data Units) and / or PDCP PDUs related to multicast has exceeded a predetermined value may be used, or information regarding the expiration of a timer used in the RLC layer (e.g., t-reassembly as described in Non-Patent Document 40) may be used, or information indicating that the number of missing RLC SDUs (Service Data Units) and / or RLC PDUs related to multicast has exceeded a predetermined value may be used. The aforementioned predetermined information may be predetermined by the standard, or it may be determined by the IAB donor CU and notified or reported to the UE. A new timer may be provided as the timer used in the PDCP layer as described above. A new timer may be provided as the timer used in the RLC layer as described above. The aforementioned information may be included as a reason in the F1 signaling, for example. For example, information regarding multicast reception status may be included as a reason for the PTM / PTP leg switching request from the UE. This allows, for example, the IAB donor care unit to obtain detailed information about the euthanasia.

[0190] The aforementioned RRC signaling may also include the same information as the aforementioned F1 signaling. This can, for example, produce the same effect as described above.

[0191] An IAB donor CU may notify an IAB donor DU and / or an IAB node of information regarding the activation / deactivation of a leg. This notification may be made using F1 signaling, for example, the UE CONTEXT SETUP REQUEST disclosed in Non-Patent Document 35 (TS38.473), or the UE CONTEXT MODIFICATION REQUEST. An IAB donor DU and / or an IAB node may notify a child IAB node and / or UE of information regarding the activation / deactivation of a leg. This notification may be made, for example, using MAC signaling. This allows for the rapid notification of such information to, for example, a child IAB node and / or UE.

[0192] This embodiment 1 enables multicast transmission from an IAB base station.

[0193] Embodiment 2. In multicast from an IAB base station, child IAB nodes and UEs may be connected simultaneously to the IAB donor DU and / or IAB node.

[0194] Figure 16 shows an example of a multicast connection from an IAB base station. In Figure 16, the IAB donor CU and IAB donor DU are connected by a wire. The IAB donor DU transmits multicast data to IAB node #1, UE #1, and UE #2. This transmission from the IAB donor DU may be done using a PTP leg or a PTM leg. IAB node #1 transmits multicast data to IAB node #2, IAB node #3, and UE #3. This transmission from IAB node #1 may be done using a PTP leg or a PTM leg. IAB node #2 transmits multicast data to UE #4 and UE #5. This transmission from IAB node #2 may be done using a PTP leg or a PTM leg. IAB node #3 transmits multicast data to UE #6. This transmission from IAB node #3 may be done using a PTP leg or a PTM leg.

[0195] Figure 16 shows an example of a connection in multicast, but the connection configuration is not limited to the form shown in Figure 16. For example, other IAB nodes may be connected to an IAB donor DU, other IAB nodes may be connected to IAB node #1, other IAB nodes may be connected to IAB node #2, other IAB nodes may be connected to IAB node #3, or other UEs may be connected. Also, there may be multiple IAB donor DUs.

[0196] As described above, the following problems arise. Specifically, the protocol stacks differ between when an IAB donor DU or IAB node sends U-plane data to an IAB node that it connects to in communication with a UE (hereinafter sometimes referred to as a child IAB node) and when an IAB donor DU or IAB node sends U-plane data to a UE.

[0197] Figure 17 shows the protocol stack between the IAB donor CU and UE. In Figure 17, the U-plane protocol stack between the IAB donor CU and UE#4 shown in Figure 16 is displayed.

[0198] In the example shown in Figure 17, the SDAP and PDCP protocols from the IAB donor CU terminate at UE#4. The GTP-U (GPRS Tunneling Protocol for User Plane) and UDP (User Datagram Protocol) protocols from the IAB donor CU terminate at IAB node #2. The IP protocol from the IAB donor CU is initially terminated at the IAB donor DU. The IP header is re-attached at the IAB donor DU, and the IP protocol from the IAB donor DU terminates at IAB node #2. The L2 and L1 protocols from the IAB donor CU terminate at the IAB donor DU.

[0199] In the example shown in Figure 17, the BAP protocol from the IAB donor DU is terminated at IAB node #1. The BAP layer processing is performed at IAB node #1, and the BAP protocol from IAB node #1 is terminated at IAB node #2.

[0200] In the example shown in Figure 17, the RLC, MAC, and PHY protocols from the IAB donor DU terminate at IAB node #1. The RLC, MAC, and PHY protocols from IAB node #1 terminate at IAB node #2. The RLC, MAC, and PHY protocols from IAB node #2 terminate at UE #4.

[0201] In the example shown in Figure 17, the U-plane data sent from IAB node #1 to IAB node #2 includes processing for the PHY, MAC, RLC, BAP, IP, UDP, GTP-U, PDCP, and SDAP protocols.

[0202] Figure 18 shows another example of a protocol stack between an IAB donor CU and an UE. In Figure 18, the U-plane protocol stack between the IAB donor CU and UE#3 shown in Figure 16 is displayed.

[0203] In the example shown in Figure 18, the SDAP and PDCP protocols from the IAB donor CU are terminated at UE#3. The GTP-U and UDP protocols from the IAB donor CU are terminated at IAB node #1. The IP protocol from the IAB donor CU is initially terminated at the IAB donor DU. The IP header is re-entered at the IAB donor DU, and the IP protocol from the IAB donor DU is terminated at IAB node #1. The L2 and L1 protocols from the IAB donor CU are terminated at the IAB donor DU.

[0204] In the example shown in Figure 18, the BAP protocol from the IAB donor DU terminates at IAB node #1.

[0205] In the example shown in Figure 18, the RLC, MAC, and PHY protocols from the IAB donor DU terminate at IAB node #1. The RLC, MAC, and PHY protocols from IAB node #1 terminate at UE #4.

[0206] In the example shown in Figure 18, the U-plane data transmitted from IAB node #1 to UE #3 includes processing for the PHY, MAC, RLC, PDCP, and SDAP protocols.

[0207] Therefore, in the examples shown in Figures 17 and 18, the protocol stack for the U-plane data that IAB node #1 sends to IAB node #2 is different from the protocol stack for the U-plane data that IAB node #1 sends to UE #3.

[0208] This leads to a problem where, during multicast data transmission from an IAB node to child IAB nodes and UEs, the differences in protocol stacks prevent the child IAB nodes and / or UEs from correctly recognizing the data.

[0209] This second embodiment discloses a method for solving these problems.

[0210] To solve the aforementioned problems, in the communication system according to this embodiment, the IAB node sets a PTM leg only for the UE. Only a PTP leg is set for the child IAB node. The IAB node may also set a PTP leg for the UE. The IAB node may use either a PTM leg or a PTP leg for transmission to the UE.

[0211] The IAB node assigns an identifier to the UE only for use in transmission using the PTM leg. This identifier may be, for example, G-RNTI and / or SC-RNTI, or other identifiers. The IAB node assigns an identifier to its child IAB node for use in transmission using the PTP leg. This identifier may be, for example, C-RNTI (see Non-Patent Document 17), or other identifiers. The IAB node may notify the IAB donor CU of the aforementioned identifiers, e.g., G-RNTI, SC-RNTI, and / or C-RNTI. This notification may be made using F1 signaling, e.g., UL RRC MESSAGE TRANSFER signaling.

[0212] The IAB donor CU configures multicast for the UE and / or the aforementioned child IAB nodes. This configuration may include information about the aforementioned identifiers, e.g., G-RNTI, SC-RNTI, and / or C-RNTI. This configuration may be performed via the aforementioned IAB nodes. The IAB donor CU may notify the IAB nodes of the configuration for the UE and / or the aforementioned child IAB nodes. This notification may be performed using F1 signaling, e.g., DL RRC MESSAGE TRANSFER signaling. The IAB node may configure multicast for the UE and / or child IAB nodes. This configuration may be performed using RRC signaling, e.g., RRC reconfiguration signaling. The UE and / or child IAB nodes may use this signaling to initiate multicast receiving operations.

[0213] Figure 19 shows an example of multicast transmission from an IAB base station. In Figure 19, the gray lightning bolts represent communication using PTM legs, and the black lightning bolts represent communication using PTP legs.

[0214] In Figure 19, the IAB donor DU sends multicast data to UE#1 and UE#2 using PTM legs. The IAB donor DU sends multicast data to IAB node #1 using only PTP legs.

[0215] Similarly, IAB node #2 sends multicast data to UE #4 and UE #5 using PTM legs. IAB node #1 sends multicast data to IAB node #2, IAB node #3, and UE #3 using only PTP legs. IAB node #3 sends multicast data to UE #6 using PTP legs.

[0216] Figure 19 shows an example of sending multicast data from IAB node #1 to UE #3 and from IAB node #3 to UE #6 using PTP legs, but PTM legs may also be used.

[0217] Only terminal IAB nodes, i.e., IAB nodes that do not have any child IAB nodes connected, may transmit to the UE using PTM legs. In other words, non-terminal IAB nodes may transmit to the UE using PTP legs. This can, for example, avoid complexity in the communication system.

[0218] Figure 20 shows another example of multicast transmission from an IAB base station. In Figure 20, gray lightning bolts represent communication using PTM legs, and black lightning bolts represent communication using PTP legs. Figure 20 shows an example where only the terminal IAB node transmits multicast data to the UE using PTM legs.

[0219] In Figure 20, multicast transmission using PTM legs is performed from IAB node #2, the terminal IAB node, to UE#4 and UE#5. PTP legs are used for other multicast transmissions.

[0220] Figure 20 shows an example of sending multicast data from IAB node #3 to UE #6 using a PTP leg. However, since IAB node #3 is also a terminal IAB node, a PTM leg may be used instead.

[0221] Other solutions are disclosed. The IAB node configures PTM legs only for child IAB nodes. Only PTP legs are configured for UEs. The IAB node may configure PTP legs for child IAB nodes. The IAB node may use either PTM legs or PTP legs for transmission to child IAB nodes.

[0222] An IAB node assigns an identifier to its child IAB nodes only, for use in transmissions using PTM legs. This identifier may be, for example, G-RNTI and / or SC-RNTI, or other identifiers. The IAB node assigns an identifier to the UE for use in transmissions using PTP legs. This identifier may be, for example, C-RNTI, or other identifiers. The IAB node may notify the IAB donor CU of the aforementioned identifiers, e.g., G-RNTI, SC-RNTI, and / or C-RNTI. This notification may be made using F1 signaling, e.g., UL RRC MESSAGE TRANSFER signaling.

[0223] The IAB donor CU configures multicast for the UE and / or the aforementioned child IAB nodes. This configuration may include information about the aforementioned identifiers, e.g., G-RNTI, SC-RNTI, and / or C-RNTI. This configuration may be performed via the aforementioned IAB nodes. The IAB donor CU may notify the IAB nodes of the configuration for the UE and / or the aforementioned child IAB nodes. This notification may be performed using F1 signaling, e.g., DL RRC MESSAGE TRANSFER signaling. The IAB node may configure multicast for the UE and / or child IAB nodes. This configuration may be performed using RRC signaling, e.g., RRC reconfiguration signaling. The UE and / or child IAB nodes may use this signaling to initiate multicast receiving operations.

[0224] Figure 21 shows another example of multicast transmission from an IAB base station. In Figure 21, gray lightning bolts represent communication using PTM legs, and black lightning bolts represent communication using PTP legs. Figure 21 shows an example where multicast data is transmitted using PTM legs only from an IAB node to child IAB nodes.

[0225] In Figure 21, PTM legs are used for multicast communication from IAB node #1 to IAB nodes #2 and #3. Multicast communication from IAB node #1 to UE #3 is performed using PTP legs. PTP legs are used for other multicast transmissions.

[0226] Figure 21 shows an example of multicast communication from IAB donor DU to IAB node #1 using a PTP leg, but a PTM leg may also be used.

[0227] Other solutions are disclosed. The aforementioned solutions may be used in combination. For example, there may be an IAB node and / or IAB donor DU that sets PTM legs only for UEs, or an IAB node and / or IAB donor DU that sets PTM legs only for child IAB nodes. In the same IAB node, PTM legs may not be set for both UEs and child IAB nodes simultaneously. In an IAB donor DU, PTM legs may not be set for both UEs and child IAB nodes simultaneously. This can, for example, improve the flexibility of the communication system.

[0228] As another example, PTM legs may be configured simultaneously for both the UE and child IAB nodes within the same IAB node. The PTM legs used for transmission to the UE and the PTM legs used for transmission to child IAB nodes may not be active simultaneously within that IAB node. For example, the method disclosed in Embodiment 1 may be used to activate / deactivate the PTM legs used for transmission to the UE and / or the PTM legs used for transmission to child IAB nodes. This allows for further improvement of the flexibility of the communication system, for example.

[0229] Figure 22 shows another example of multicast transmission from an IAB base station. In Figure 22, gray lightning bolts represent communication using PTM legs, and black lightning bolts represent communication using PTP legs.

[0230] In Figure 22, multicast communication using PTM legs is performed from the IAB donor DU to UE#1 and UE#2. Multicast communication using PTP legs is performed from the IAB donor DU to IAB node #1.

[0231] In Figure 22, multicast communication using PTM legs is performed from IAB node #1 to IAB node #2 and IAB node #3. Multicast communication using PTP legs is performed from IAB node #1 to UE #3.

[0232] In Figure 22, multicast communication using PTM legs is performed from IAB node #2 to UE #4 and UE #5. Multicast communication using PTP legs is performed from IAB node #3 to UE #6.

[0233] Figure 22 shows an example of multicast communication using PTM legs from the IAB donor DU to UE#1 and UE#2. However, multicast communication using PTM legs may also be performed from the IAB donor DU to IAB node #1. In this case, multicast communication using PTP legs is performed from the IAB donor DU to UE#1 and UE#2.

[0234] Figure 22 shows an example of multicast communication using PTM legs from IAB node #1 to IAB nodes #2 and #3. However, multicast communication using PTM legs may also be performed from IAB node #1 to UE #3. In this case, multicast communication using PTP legs is performed from IAB node #1 to IAB nodes #2 and #3.

[0235] In this second embodiment, the IAB donor DU and / or IAB node assign an identifier to either the UE or the child IAB node for use in transmission using the PTM leg. This identifier may be, for example, G-RNTI and / or SC-RNTI, or other identifiers. The IAB node assigns an identifier to the UE and / or child IAB node for use in transmission using the PTP leg. This identifier may be, for example, C-RNTI, or other identifiers. The IAB node may notify the IAB donor CU of the aforementioned identifiers, e.g., G-RNTI, SC-RNTI, and / or C-RNTI. This notification may be made using F1 signaling, e.g., UL RRC MESSAGE TRANSFER signaling.

[0236] The IAB donor CU configures multicast for the UE and / or the aforementioned child IAB nodes. This configuration may include information about the aforementioned identifiers, e.g., G-RNTI, SC-RNTI, and / or C-RNTI. This configuration may be performed via the aforementioned IAB nodes. The IAB donor CU may notify the IAB nodes of the configuration for the UE and / or the aforementioned child IAB nodes. This notification may be performed using F1 signaling, e.g., DL RRC MESSAGE TRANSFER signaling. The IAB node may configure multicast for the UE and / or child IAB nodes. This configuration may be performed using RRC signaling, e.g., RRC reconfiguration signaling. The UE and / or child IAB nodes may use this signaling to initiate multicast receiving operations.

[0237] This second embodiment makes it possible to prevent protocol stack discrepancies in multicast data transmission from an IAB node to child IAB nodes and UEs, and as a result, multicast transmission becomes possible even when both child IAB nodes and UEs are connected to an IAB donor DU and / or IAB node.

[0238] Modification Example 1 of Embodiment 2 Multicast transmission using PTM legs may be performed for both the UE and the IAB node. A plurality of PTM legs may be provided from one IAB donor DU. A plurality of PTM legs may be provided from one IAB node. In the foregoing, some PTM legs may be used for transmission to the UE, and other PTM legs may be used for transmission to the IAB node.

[0239] The RLC settings, MAC settings, and / or PHY settings in the PTM leg may be the same for the UE and for the IAB node. This can avoid, for example, the complexity in the communication system.

[0240] As another example, the foregoing settings may be different for the UE and for the IAB node. This can improve, for example, the flexibility of the communication system.

[0241] The resources used in the PTM leg, such as time resources, frequency resources, and / or spatial resources (e.g., beams), may be the same for the UE and for the IAB node. This can improve, for example, the efficiency in the communication system.

[0242] As another example, the foregoing resources may be different for the UE and for the IAB node. This can avoid, for example, the complexity in the communication system.

[0243] FIG. 23 is a diagram showing an example in which a plurality of PTM legs are provided in an IAB node. In the example shown in FIG. 23, in the IAB node, a PTM leg for the child IAB node and a PTM leg for the UE are provided respectively. In the example shown in FIG. 23, in the multicast transmission from the IAB node to the child IAB node and the UE, the PTM leg and the PTP leg are set.

[0244] In multicast transmissions using PTM legs for the UE and child IAB nodes, different identifiers, such as G-RNTI, may be used. An IAB node may assign different identifiers to child IAB nodes and UEs. This allows, for example, the UE and / or child IAB nodes to receive multicasts intended for their own devices.

[0245] A predetermined offset may be set between the two identifiers. For example, the G-RNTI for the IAB node may be the G-RNTI for the UE plus a predetermined value. This offset may be publicly announced or notified individually.

[0246] As another example, the range of identifiers that can be used for UEs and those that can be used for child IAB nodes may be separated. These ranges may be defined, for example, by a standard. This can, for example, avoid the complexity of assigning such identifiers.

[0247] A CORESET (Control Resource Set) (see Non-Patent Literature 14 (TS38.213)) may be provided for the UE to receive multicast transmitted using PTM legs, and a CORESET may be provided for the child IAB node to receive multicast transmitted using PTM legs. Both of the aforementioned CORESETs may be provided as system information, or they may be individually notified to the IAB nodes from the IAB donor CU. This makes it possible to avoid, for example, the complexity of multicast reception.

[0248] This modified version 1 enables multicast transmission using PTM legs from an IAB node to both child IAB nodes and UEs, thereby improving the efficiency of multicast communication.

[0249] Embodiment 3. 3GPP is considering supporting various services using SL communication in both EPS and 5G core systems (see Non-Patent Documents 1, 16, 20, 21, 22, and 23). SL communication is conducted between terminals. In addition to direct communication between terminals, SL communication also proposes communication between UEs and NWs via relays (see Non-Patent Documents 20 (3GPP TR23.703), 23 (3GPP TS23.303), and 27 (3GPP TR38.836)). Relays between UEs and NWs are sometimes referred to as UE-to-NW relays or UE-NW relays. In this disclosure, a UE that performs relays between UEs and NWs may be referred to as a relay UE.

[0250] For example, there may be a need to communicate not only between UEs within the coverage of a RAN (Radio Access Network) node (e.g., gNB), but also between more distant UEs and RAN nodes. In such cases, a method using UE-to-NW relays can be considered. For example, communication between a gNB and a UE (sometimes referred to as a remote UE) can be performed via a relay UE. Communication between the gNB and the relay UE is performed using Uu, and communication between the relay UE and the remote UE is performed using PC5.

[0251] In communication systems that support communication via relays, the challenge lies in improving the communication quality between terminals and the network. For example, how to schedule communication between a remote UE and a gNB via a relay UE. Unlike direct communication between a UE and a network, communication between a UE and a network via a relay UE requires scheduling on both the Uu and PC5. Therefore, simply using the scheduling methods for direct communication between a UE and a network, or for direct communication between UEs, is insufficient for scheduling communication between a remote UE and a network via a relay UE.

[0252] In SL communication between UEs, the transmitting UE (sometimes referred to as UE-TX) schedules communication from UE-TX to UE-RX for the receiving UE (sometimes referred to as UE-RX). There are two methods for scheduling communication from UE-TX to UE-RX: one where the gNB directly connected to the UE-TX performs the scheduling (sometimes referred to as Mode 1), and another where the UE-TX performs the scheduling itself (sometimes referred to as Mode 2).

[0253] In communication between a remote UE and a gNB via a relay UE, the remote UE is connected to the gNB. This connection may be an RRC connection. In this case, where the remote UE is connected to the gNB via a relay UE rather than directly to the gNB, the scheduling method for communication from the remote UE to the gNB has not been disclosed in any existing standards.

[0254] This third embodiment discloses a method for solving these problems.

[0255] As a method to solve the aforementioned problems, this embodiment discloses a scheduling method for communication from a gNB to a remote UE in communication between a remote UE and a gNB via a relay UE. In this scheduling method, the gNB performs scheduling for DL ​​and SL. Scheduling for DL ​​and SL may be performed individually. The gNB is a gNB to which the remote UE connects via a relay UE. The gNB may also be a gNB to which the relay UE connected to the remote UE connects. The connection may be an RRC connection. In this scheduling method, the gNB transmits DL scheduling information to the relay UE. The relay UE transmits SL scheduling information to the remote UE. The DL scheduling information and the SL scheduling information may be limited to communication between the remote UE and the gNB via the relay UE.

[0256] DL scheduling information is scheduling information related to communication from the gNB to the relay UE in communication between the remote UE and the gNB via the relay UE. DL scheduling information may also be information related to the scheduling of DL data and / or FB (Feedback) for DL ​​data (sometimes referred to as DL FB). Information related to the scheduling of DL data may include, for example, DL control information. Information related to the scheduling of DL data may include, for example, information about the PDSCH that transmits DL data, information related to the scheduling of DL FB, etc. Information related to the scheduling of DL FB may include, for example, information about the timing of transmitting DL FB information, information about PUCCH, etc. Information related to PUCCH may include, for example, information indicating PUCCH settings. Information related to DL FB may include, for example, HARQ FB information, CSI information, etc. Information related to the aforementioned PDSCH and PDCCH may include, for example, resource allocation information for the CH.

[0257] If the PUCCH setting is transmitted via RRC signaling, an identifier may be assigned to the PUCCH setting, and the identifier information of the PUCCH setting may be included as information regarding the scheduling of the DL's FB as described above.

[0258] SL scheduling information is scheduling information related to communication from the relay UE to the remote UE in communication between the remote UE and the gNB via the relay UE. SL scheduling information may also be information regarding the scheduling of SL control information and / or SL data and / or FB (sometimes referred to as SL FB) for the SL data. Information regarding the scheduling of SL control information may, for example, be information regarding the PSCCH that transmits the SL control information. Information regarding the scheduling of SL control information may, for example, be information regarding the PSSCH that transmits the SL control information. Information regarding the scheduling of SL data may, for example, be information regarding the PSSCH that transmits the SL data. Information regarding the scheduling of SL FB may include, for example, information regarding the PSFCH that transmits the FB on the SL, information regarding the timing of the FB transmission, information regarding the PUCCH that transmits the FB on the UL, information regarding the transmission timing, etc. Information regarding the PSFCH may, for example, include information indicating the PSFCH setting. SL FB information may, for example, be HARQ FB information on the SL, CSI information on the SL, etc. The information regarding PSCCH, PSSCH, PSFCH, and PUCCH mentioned above may include, for example, resource allocation information for the CH.

[0259] If a PSFCH setting is notified via RRC signaling, an identifier may be assigned to the PSFCH setting, and the identifier information of the PSFCH setting may be included in the information regarding the scheduling of the SL's FB as described above. If a PUCCH setting is notified via RRC signaling, an identifier may be assigned to the PUCCH setting, and the identifier information of the PUCCH setting may be included in the information regarding the scheduling of the SL's FB as described above.

[0260] The DL scheduling information may include information indicating that it is for communication from the gNB to the remote UE via the relay UE. The DL scheduling information may include information regarding the remote UE that is the target of the relay communication. This information may be, for example, the identifier of the remote UE. The DL scheduling information may include information regarding the relay UE that performs the relay. This information may be, for example, the identifier of the relay UE. The SL scheduling information may include information indicating that it is for communication from the gNB to the remote UE via the relay UE. The SL scheduling information may include information regarding the remote UE that is the target of the relay communication. This information may be, for example, the identifier of the remote UE. The SL scheduling information may include information regarding the relay UE that performs the relay. This information may be, for example, the identifier of the relay UE.

[0261] The relay UE may transmit SL scheduling information to the remote UE. The SL scheduling information may include information indicating that it is for communication from the gNB to the remote UE via the relay UE. The SL scheduling information may include information regarding the remote UE that is the target of the relay communication. This information may be, for example, the identifier of the remote UE. The SL scheduling information may include information regarding the relay UE that performs the relay. This information may be, for example, the identifier of the relay UE.

[0262] The DL scheduling information and the SL scheduling information may include information for associating with each other.

[0263] This document discloses a method for transmitting DL scheduling information. The gNB notifies the relay UE of the DL scheduling information via L1 / L2 signaling. The gNB may also include this information in the DCI (Downlink Control Information) and transmit it via PDCCH. This allows the gNB to transmit the information to the relay UE earlier. Furthermore, since the method of transmitting this information can be aligned with the conventional DL scheduling method, it is possible to avoid complicating the processing at the gNB and relay UE.

[0264] Another transmission method is disclosed. The gNB transmits DL scheduling information to the relay UE via MAC signaling. This information may also be transmitted in the MAC CE (Control Element). In this way, the gNB can transmit the information to the relay UE early and with a low error rate.

[0265] Other transmission methods are disclosed. The gNB notifies the relay UE of DL scheduling information via RRC signaling. This information may also be included in an RRC message. In this way, the gNB can transmit a large amount of information to the relay UE with a low error rate.

[0266] This document discloses a method for transmitting scheduling information for SL. The gNB transmits the SL scheduling information to the relay UE via L1 / L2 signaling. The gNB may also transmit this information via PDCCH by including it in the DCI. This allows the gNB to transmit the information to the relay UE earlier. Furthermore, since the method of transmitting this information can be aligned with the conventional DL scheduling method, it is possible to avoid complexity in the processing at the gNB and relay UE.

[0267] Other transmission methods are disclosed. The gNB transmits scheduling information for the SL to the relay UE via MAC signaling. The gNB may also transmit this information in MAC CE. In this way, the gNB can transmit the information to the relay UE early and with a low error rate.

[0268] Other transmission methods are disclosed. The gNB transmits scheduling information for the SL to the relay UE via RRC signaling. The gNB may also transmit this information in an RRC message. In this way, the gNB can transmit a large amount of information to the relay UE with a low error rate.

[0269] An RNTI for relay communication may be provided. For example, it may be called Relay-RNTI. Relay-RNTI can be used to identify PDCCHs that contain DL scheduling information and / or SL scheduling information for relay communication, or PDCCHs that schedule MAC signaling containing such information, or PDCCHs that schedule RRC signaling containing such information. For example, these PDCCHs can be masked with Relay-RNTI. In this way, the relay UE can recognize early on that the information is DL scheduling information and / or SL scheduling information for relay communication.

[0270] Alternatively, PDCCHs containing DL scheduling information and / or SL scheduling information for relay communication, or PDCCHs scheduling MAC signaling containing such information, or PDCCHs scheduling RRC signaling containing such information, can be identified using an RNTI for identifying the remote UE, such as a C-RNTI. For example, these PDCCHs can be masked with the remote UE's C-RNTI. In this way, the relay UE can recognize early on that the PDCCHs contain DL scheduling information and / or SL scheduling information for relay communication to the remote UE.

[0271] This document discloses a method for transmitting SL scheduling information from a relay UE to a remote UE. The relay UE transmits the SL scheduling information to the remote UE using the SL's L1 / L2 signaling. This information may also be included in SCI (Sidelink Control Information) and transmitted via PSCCH and / or PSSCH. This allows the relay UE to transmit the information to the remote UE earlier. Furthermore, since the method of transmitting this information can be aligned with the conventional SL scheduling method, it is possible to avoid complicating processing at both the relay UE and the remote UE.

[0272] Another transmission method is disclosed. The relay UE transmits scheduling information for the SL to the remote UE via the SL's MAC signaling. The relay UE may also transmit this information in the SL's MAC CE. In this way, the relay UE can transmit the information to the remote UE early and with a low error rate.

[0273] Other transmission methods are disclosed. The relay UE notifies the remote UE of scheduling information for the SL using the SL's RRC signaling. The relay UE may also transmit this information in the SL's RRC message. In this way, the relay UE can transmit a large amount of information to the remote UE with a low error rate.

[0274] Figure 24 is a sequence diagram showing an example of a scheduling method for communication from a gNB to a remote UE via a relay UE in Embodiment 3. In the example in Figure 24, the gNB notifies the relay UE of separate scheduling information for DL ​​and SL. In the example in Figure 24, when communication data to the remote UE is generated, the gNB performs DL scheduling to transmit the communication data. In step ST2401, the gNB transmits DL scheduling information to the relay UE. In the example in Figure 24, this information is notified via PDCCH. In step ST2402, the gNB uses this information to transmit communication data to the remote UE using PDSCH. In step ST2401, the relay UE, having received DL scheduling information from the gNB, uses this information to receive communication data from the gNB in ​​step ST2402.

[0275] In step ST2403, the relay UE transmits DL FB information to the gNB according to the DL scheduling information received in step ST2401. In the example in Figure 24, this information is transmitted via PUCCH. In the example in Figure 24, the HARQ feedback Ack is used as the DL FB information. Upon receiving the Ack, the gNB transmits SL scheduling information to the relay UE in step ST2404. In the example in Figure 24, this information is transmitted via PDCCH.

[0276] If the DL's FB information is Nack, the gNB should repeat the processing from step ST2401. In this way, the gNB can perform the retransmission of communication data to the remote UE for the relay UE.

[0277] Upon receiving the SL scheduling information, the relay UE transmits the SL scheduling information to the remote UE in step ST2405, for transmitting the communication data received from the gNB in ​​step ST2402. The relay UE also transmits the communication data received in step ST2402 to the remote UE in step ST2406, using this information. The SL scheduling information may also be transmitted along with the communication data. This information may be used by the remote UE to receive the communication data. In this way, the remote UE can receive the communication data from the gNB via the relay UE.

[0278] In step ST2407, the remote UE transmits SL FB information to the relay UE. In the example in Figure 24, this information is transmitted using PSFCH. The scheduling information for the SL FB information should be included in the SL scheduling information. In step ST2405 and / or step ST2406, the remote UE, having received the SL scheduling information, should use this information to transmit the SL FB information to the relay UE. In the example in Figure 24, the SL FB information is the HARQ feedback Ack information. Upon receiving the Ack information, the relay UE transmits the SL FB information to the gNB in ​​step ST2408. In the example in Figure 24, this information is transmitted using PUCCH. The scheduling information for the SL FB information should be included in the SL scheduling information. In step ST2404, the relay UE, having received the SL scheduling information, should use this information to transmit the SL FB information to the gNB. In this way, the gNB can obtain the SL FB information from the remote UE.

[0279] If the FB information of the SL received in step ST2408 is Nack, the gNB should repeat the processing from step ST2404. The relay UE can then retransmit the communication data from the relay UE to the remote UE.

[0280] One or more DL scheduling information may be associated with one or more SL scheduling information. For example, communication data from a gNB to a remote UE may be scheduled in DL with the notification of one DL scheduling information, and in SL with the notification of multiple SL scheduling information. This method is effective when sufficient wireless resources can be secured with one scheduling in DL, but not with one scheduling in SL.

[0281] This approach enables scheduling of communication from the gNB to the remote UE in communication between the remote UE and the gNB via the relay UE. Therefore, communication from the gNB to the remote UE via the relay UE becomes possible. Furthermore, scheduling that considers the feedback rates of the SL and DL is possible, thus improving communication quality.

[0282] This paper discloses an alternative method for scheduling communication between a remote UE and a gNB via a relay UE, specifically focusing on the differences from the method disclosed above.

[0283] In this alternative method, the gNB performs scheduling for DL ​​and SL together. The gNB transmits the DL and SL scheduling information to the relay UE. The relay UE, having received the DL and SL scheduling information from the gNB, transmits the SL scheduling information to the remote UE. The DL and SL scheduling information may be limited to communication between the remote UE and the gNB via the relay UE.

[0284] In the other method, the DL and SL scheduling information may be appropriately applied to the DL and SL scheduling information disclosed above.

[0285] An offset may be provided between the DL data transmission timing and the SL scheduling information transmission timing and / or SL data transmission timing. Alternatively, the offset may be the DL data reception timing instead of the DL data transmission timing. Information regarding this offset may be included in the DL scheduling information or SL scheduling information in the other method. By receiving this information, the relay UE can recognize the SL scheduling information and / or SL data transmission timing after DL data reception. This reduces the amount of SL scheduling information required.

[0286] This invention discloses a method for transmitting scheduling information for DL ​​and SL in an alternative manner. The gNB transmits the scheduling information for DL ​​and SL to the relay UE via L1 / L2 signaling. This information may be included in a single DCI and transmitted via PDCCH. A separate DCI may be provided for the relay. The information may also be included in the relay DCI and transmitted via PDCCH. By transmitting the scheduling information for DL ​​and SL together in this way, the amount of signaling can be reduced. In addition, the gNB can transmit this information to the relay UE earlier. Furthermore, since the method of transmitting this information can be aligned with the conventional DL scheduling method, it is possible to avoid complexity in the processing at the gNB and relay UE.

[0287] Other transmission methods are disclosed. The gNB transmits scheduling information for DL ​​and SL to the relay UE via MAC signaling. The gNB may transmit this information in a single MAC CE. A MAC CE for relays may be provided. The gNB may transmit this information in the MAC CE for relays. This reduces the amount of signaling. In addition, the gNB can transmit this information to the relay UE early and with a low error rate.

[0288] Other transmission methods are disclosed. The gNB transmits scheduling information for DL ​​and SL to the relay UE via RRC signaling. The gNB may transmit this information in a single RRC message. A separate RRC message for relays may be provided. The gNB may transmit this information in the relay RRC message. In this way, the gNB can transmit a large amount of information to the relay UE with a low error rate.

[0289] A relay UE that has received scheduling information for DL ​​and SL from the gNB transmits the received SL scheduling information to the remote UE. The transmission method may be appropriately applied using the method disclosed above. The same effects as the method disclosed above can be obtained.

[0290] Figure 25 is a sequence diagram showing another example of a scheduling method for communication from a gNB to a remote UE via a relay UE, according to Embodiment 3. In Figure 25, steps common to Figure 24 are given the same step numbers, and common explanations are omitted. In the example in Figure 25, the gNB transmits both DL and SL scheduling information to the relay UE. In the example in Figure 25, when communication data, which is downlink data to the remote UE, is generated, the gNB performs DL scheduling and SL scheduling in order to transmit the communication data. For example, in SL scheduling, the time required for retransmission of DL data and the maximum number of retransmissions may be considered. When communication data to the remote UE is generated, the gNB transmits DL scheduling information and SL scheduling information to the relay UE in step ST2501. In the example in Figure 25, this information is notified in a single PDCCH. This information may also be included in a single DCI and notified in a PDCCH. This reduces the amount of signaling.

[0291] Furthermore, since the gNB transmits SL scheduling information to the relay UE along with DL scheduling information, the relay UE can immediately transmit SL scheduling information to the remote UE and transmit communication data to the remote UE after receiving communication data from the gNB. In other words, low latency characteristics can be improved in communication from the gNB to the remote UE via the relay UE.

[0292] Similar to the method disclosed above, one or more DL scheduling information may be associated with one or more SL scheduling information. The same effects as when applying the method disclosed above can be obtained.

[0293] Figure 26 is a sequence diagram illustrating another example of a method for scheduling communication from a gNB to a remote UE via a relay UE, according to Embodiment 3. In Figure 26, steps common to Figure 25 are given the same step numbers, and common explanations are omitted. The example in Figure 26 discloses the case where the relay UE fails to receive DL data from the gNB.

[0294] In step ST2601, the relay UE sends a Nack to the gNB as DL FB information. Upon receiving the Nack as DL FB information from the relay UE, the gNB performs DL scheduling and SL scheduling again in step ST2602 and sends DL scheduling information and SL scheduling information to the relay UE. The DL scheduling information and / or SL scheduling information may include information indicating that it is a retransmission. This allows the relay UE to recognize that it is retransmitted data. In step ST2603, the gNB retransmits the communication data to the remote UE. The relay UE, having successfully received the communication data to the remote UE, may then perform the processing in steps ST2405 to ST2408 as disclosed in Figure 24.

[0295] If the Remote UE fails to receive the communication data transmitted by the Relay UE in step ST2406, the Remote UE sends a Nack to the Relay UE as FB information for the SL in step ST2407. In step ST2408, the Relay UE sends a Nack to the gNB as FB information for the SL. Upon receiving the Nack from the Relay UE as FB information for the SL, the gNB may perform step ST2501 and send scheduling information for the SL to the Relay UE. The DL scheduling information does not need to be included in this transmission. The scheduling information for the SL may include information indicating that the communication data is being retransmitted on the SL. Upon receiving the scheduling information for the SL in step ST2501, the Relay UE executes steps ST2405 and ST2406 again to retransmit the communication data. If the Remote UE receives the retransmitted communication data, in steps ST2407 and ST2408, the Remote UE sends an Ack to the gNB via the Relay UE as FB information for the SL. In this way, retransmission processing can be performed when the Relay UE fails to send or receive communication data to or from the Remote UE.

[0296] If the gNB receives a Nack from the relay UE as FB information for the SL in step ST2408, it may send scheduling information for the SL to the relay UE by executing step ST2404 as shown in Figure 24. The processing in steps ST2404 to ST2408 may also be performed to retransmit the communication data. In this way, it becomes possible to perform retransmission processing when the relay UE is unable to send the communication data to the remote UE.

[0297] In this way, by notifying DL and SL scheduling information together, the amount of signaling can be reduced. Also, since the SL scheduling information is notified to the relay UE together with the DL scheduling information, the relay UE can immediately use the SL scheduling information to transmit the DL data received from the gNB as SL data to the remote UE after receiving DL data from the gNB. Furthermore, communication from the gNB to the remote UE via the relay UE can be performed earlier, resulting in lower latency. In addition, by providing a DCI for the relay, it becomes possible to set both DL scheduling information and SL scheduling information with a single DCI, thereby reducing the occurrence of malfunctions in communication from the gNB to the remote UE via the relay UE.

[0298] This paper discloses an alternative method for scheduling communication between a remote UE and a gNB via a relay UE, specifically focusing on the differences from the method disclosed above.

[0299] The relay UE transmits the FB of the SL and the FB of the DL together to the gNB. The FB of the SL and the FB of the DL may be limited to communication between the remote UE and the gNB via the relay UE.

[0300] The scheduling information for DL ​​and / or SL may include scheduling information for transmitting SL FB and DL FB together. The combined information for SL FB and DL FB may be used as relay FB. Uplink Control Information (UCI) may be provided for relay FB. Scheduling information for relay FB may be included. Scheduling information for relay FB may include, for example, information about the PUCCH that transmits the FB on the UL, information about the transmission timing of the FB, etc. Information about the PUCCH may include, for example, resource allocation information for the CH.

[0301] The PUCCH setting that transmits the FB on the UL may be notified by RRC signaling. In this case, an identifier may be assigned to the PUCCH setting, and the identifier of the PUCCH setting may be included in the information regarding the scheduling of the FB as described above.

[0302] Aside from the scheduling information for SL and DL's FB, the DL and SL scheduling information disclosed above should be applied as appropriate.

[0303] The method for transmitting scheduling information for DL ​​and SL from the gNB to the relay UE can be appropriately applied using the method disclosed above. The same effect as the method disclosed above can be obtained.

[0304] A relay UE that has received scheduling information for DL ​​and SL from the gNB transmits the SL scheduling information to the remote UE. The transmission method may be appropriately applied using the method disclosed above. The same effects as the method disclosed above can be obtained.

[0305] Figure 27 is a sequence diagram showing another example of a scheduling method for communication from a gNB to a remote UE via a relay UE, according to Embodiment 3. In Figure 27, steps common to Figure 25 are given the same step numbers, and common explanations are omitted. In the example in Figure 27, the relay UE transmits the FB information of the SL and the FB information of the DL together to the gNB. That is, in step ST2701, the relay UE transmits the FB information of the SL and the FB information of the DL, received from the remote UE in step ST2407, together to the gNB. In the example in Figure 27, this information is transmitted in a single PUCCH. The FB information of the DL and the FB information of the SL may be included in a single UCI. This UCI may be transmitted in a single PUCCH. This reduces the amount of signaling.

[0306] Scheduling information for FB transmission of one or more DLs may be associated with scheduling information for FB transmission of one or more SLs. This may be set according to the relationship between the one or more DL scheduling information and the one or more SL scheduling information disclosed above. Scheduling is also possible for DL ​​FBs and SL FBs according to the correspondence between DL scheduling information and the one or more SL scheduling information.

[0307] Figure 28 is a sequence diagram showing another example of a method for scheduling communication from a gNB to a remote UE via a relay UE, according to Embodiment 3. In Figure 28, steps common to Figure 27 are given the same step numbers, and common explanations are omitted. The example in Figure 28 discloses the case where the remote UE fails to receive the SL data from the relay UE.

[0308] In step ST2801, the remote UE sends a Nack to the relay UE as FB information for the SL. Upon receiving the Nack from the remote UE as FB information for the SL, the relay UE sends the DL's FB information (here, Ack) and the SL's FB information (here, Nack) together in a single PUCCH in step ST2802. The gNB, having received the DL's FB information and the SL's FB information, can recognize that communication data to the remote UE was not sent on the SL. In step ST2803, the gNB performs scheduling for the SL again and sends the SL scheduling information to the relay UE. The SL scheduling information may also include information indicating that it is a retransmission. In this case, the relay UE can recognize that it is a schedule for retransmission data. The relay UE performs the retransmission process for the communication data to the remote UE in steps ST2804 and ST2805. Upon receiving the communication data to the remote UE, the remote UE sends an Ack to the relay UE as FB information for the SL in step ST2806. In step ST2807, the relay UE sends an Ack to the gNB as FB information for the SL. Upon receiving the Ack from the relay UE as FB information for the SL, the gNB can recognize that communication data to the remote UE has been sent to the remote UE.

[0309] Figure 29 is a sequence diagram illustrating another example of a method for scheduling communication from a gNB to a remote UE via a relay UE, according to Embodiment 3. In Figure 29, steps common to Figure 28 are given the same step numbers, and common explanations are omitted. The example in Figure 29 discloses the case where the relay UE fails to receive DL data from the gNB.

[0310] In step ST2901, the relay UE sends a Nack to the gNB as the DL's FB information. The Nack may also be sent together as the SL's FB information. A relay UE that fails to receive communication data from the gNB to the remote UE cannot send communication data to the remote UE. Therefore, the relay UE will not receive the SL's FB information from the remote UE. In the example in Figure 29, the DL's FB information and the SL's FB information are sent in a single PUCCH.

[0311] In step ST2901, the gNB receives a Nack as the DL's FB information. In step ST2503, it performs DL scheduling and SL scheduling again and sends the DL scheduling information and SL scheduling information to the relay UE. In step ST2902, the communication data to the remote UE is retransmitted from the gNB to the relay UE. Upon receiving this communication data, the relay UE performs retransmission processing of the communication data to the remote UE in steps ST2804 and ST2805. As a result of the retransmission process, the communication data is sent to the remote UE, and in step ST2806, the relay UE receives an Ack as the SL's FB information. In step ST2903, it sends the DL's FB information as an Ack and the SL's FB information as an Ack together to the gNB. In the example in Figure 29, the DL's FB information and the SL's FB information are sent in a single PUCCH. In this way, the gNB can recognize that the communication data to the remote UE has been sent to the remote UE.

[0312] If a gNB receives a Nack as FB information for the DL in step ST2901, it may add 1 to the DL retransmission count. This allows the DL to be retransmitted up to its maximum number of retransmissions. Alternatively, if a gNB receives a Nack as FB information for the SL in step ST2901, it may add 1 to the SL retransmission count. This allows the SL to be retransmitted up to its maximum number of retransmissions. In this case, the SL can be retransmitted up to its maximum number of retransmissions, including the DL's retransmission count. Alternatively, if a gNB receives a Nack as FB information for the DL in step ST2901, it may not add 1 to the SL retransmission count. This allows the SL to be retransmitted up to its maximum number of retransmissions. In this case, the SL can be retransmitted up to its maximum number of retransmissions, without including the DL's retransmission count. This is effective when you want to improve the success rate of sending and receiving with the SL.

[0313] The maximum number of DL retries and the maximum number of SL retries may be set individually. This allows for flexible settings for DL ​​and SL. The maximum number of DL retries and the maximum number of SL retries may be the same. They may also be a single maximum number of retries. This makes retransmission processing easier. The maximum number of DL retries and the maximum number of SL retries may be statically determined by standards, etc. Alternatively, the gNB may set them. The gNB's RRC may set them. If the gNB has a CU and DU separation configuration, the gNB's CU may set them and notify the DU.

[0314] In this way, by having the relay UE transmit both the SL's FB information and the DL's FB information to the gNB together, the amount of signaling can be reduced. Also, since the relay UE no longer needs to send the SL's FB information and the DL's FB information separately to the gNB, the transmission power of the relay UE can be reduced. Furthermore, by providing a UCI for FB communication from the gNB to the remote UE via the relay UE, it becomes possible to configure the DL's FB and the SL's FB with a single UCI, thereby reducing the occurrence of malfunctions in communication from the gNB to the remote UE via the relay UE.

[0315] Modification 1 of Embodiment 3. Embodiment 3 disclosed a method for scheduling communication from the gNB to the remote UE in communication between the remote UE and the gNB via a relay UE. Modification 1 of Embodiment 3 discloses a method for scheduling communication from the remote UE to the gNB in ​​communication between the remote UE and the gNB via a relay UE.

[0316] In this modified example 1, the gNB performs scheduling for UL and SL. The gNB may perform scheduling for UL and SL individually. The gNB is connected to by the remote UE via a relay UE. The gNB may also be connected to the relay UE that connects to the remote UE. The connection may be an RRC connection. In this way, by having the gNB perform scheduling for SL and UL, it becomes possible to easily adjust the transmission timing of SL and UL.

[0317] Other scheduling methods are disclosed. A remote UE may perform scheduling for SL. By having the remote UE perform scheduling for SL, scheduling that takes into account the radio wave propagation conditions and load conditions in SL becomes possible. A remote UE may perform scheduling for SL, and a gNB may perform scheduling for UL. The gNB may be a gNB connected to a relay UE connected to the remote UE. The connection may be an RRC connection.

[0318] The remote UEs that perform scheduling for SL (Service Level) may be limited. For example, a remote UE may perform scheduling for SL when it connects to a gNB (gangstone Network Boundary) via a relay UE. This connection may be an RRC (Remote Relay Control) connection. Alternatively, a remote UE may perform scheduling for SL when it is out of coverage (OOC) of the gNB it connects to via the relay UE. Alternatively, a remote UE may perform scheduling for SL when it is out of coverage of any gNB. By limiting the remote UEs in this way, it is possible to avoid the increase in processing load and processing time that would result from the remote UEs performing scheduling for the gNBs to communicate with the remote UEs via the relay UEs. Furthermore, it is possible to improve the low-latency characteristics of communication between the remote UEs and gNBs via the relay UEs.

[0319] It may be possible to configure whether the gNB or the remote UE performs the scheduling for SL. This configuration may be performed by the gNB. The gNB may also configure the remote UE to perform scheduling for SL. Mode 1 may be defined as the case where the gNB performs scheduling for SL, and Mode 2 as the case where the remote UE performs scheduling for SL, and the gNB may configure the modes it performs for the remote UE. In this way, for example, it becomes possible to configure the node that performs scheduling for SL depending on the radio wave propagation conditions and load conditions. For example, if the radio wave propagation conditions and load conditions for SL fluctuate greatly, the node that performs scheduling for SL may be set to the remote UE, and if there are not many fluctuations, the node that performs scheduling for SL may be set to the gNB. In this way, scheduling that is appropriate for the radio wave propagation conditions and load conditions for SL can be performed, and communication speed and communication quality can be improved.

[0320] This document discloses the notification method used when a gNB notifies a remote UE of the node that will perform scheduling for SLs. The gNB notifies the remote UE of information regarding the node that will perform scheduling for SLs (hereinafter sometimes referred to as the SL scheduling node). This information regarding the SL scheduling node may be information indicating the gNB or the remote UE, or information indicating the mode. The gNB may send this information regarding the SL scheduling node to the remote UE via RRC signaling. The gNB may also send this information in an RRC message. The gNB may also send this information in an RRC reset message. By receiving the information regarding the SL scheduling node sent from the gNB, the remote UE can recognize the node that will perform scheduling for SLs. This allows for flexible configuration of the node that will perform scheduling for SLs.

[0321] Another method is disclosed. Information regarding the SL scheduling node may be transmitted from the gNB to the relay UE via RRC signaling, and the relay UE, upon receiving the information via the signaling, may transmit the information to the remote UE via the SL's RRC signaling. In this way, the remote UE can receive the information regarding the SL scheduling node transmitted from the gNB. This allows for flexible configuration of the node that performs scheduling for the SL.

[0322] Another method is disclosed. The gNB may transmit information about the scheduling node for the SL to the remote UE via MAC signaling. The gNB may also transmit this information in MAC CE. The gNB may transmit this information to the relay UE via MAC signaling, and the relay UE, upon receiving the information via the signaling, may transmit the information to the remote UE via the SL's MAC signaling. In this way, the remote UE can receive information about the scheduling node for the SL transmitted from the gNB, allowing for flexible configuration of the node that performs scheduling for the SL. Furthermore, using MAC signaling enables early notification with a low error rate.

[0323] Other methods are disclosed. The gNB may transmit information regarding the scheduling node for the SL to the remote UE via L1 / L2 signaling. The gNB may transmit this information to the relay UE via L1 / L2 signaling, and the relay UE, upon receiving the information via the signaling, may transmit the information to the remote UE via the SL's L1 / L2 signaling. For example, the information may be included in the DCI and transmitted from the gNB to the relay UE via PDCCH, and the relay UE, upon receiving the information in the DCI, may include the information in the SCI and transmit it to the remote UE via PSSCH. In this way, the remote UE can receive information regarding the scheduling node for the SL transmitted from the gNB, allowing for flexible configuration of the node that performs scheduling for the SL. Furthermore, using L1 / L2 signaling enables earlier notification.

[0324] The remote UE may request the gNB to configure the scheduling node for the SL. The remote UE may also request the gNB to change the scheduling node for the SL. Information regarding the configuration or modification of the scheduling node for the SL should be provided and sent from the remote UE to the gNB. This information may include information indicating the gNB or the remote UE, or it may include information indicating the mode.

[0325] The remote UE may send information regarding the configuration or modification of the scheduling node for the SL to the gNB via RRC signaling. The remote UE may also include this information in an RRC message. Upon receiving this information from the remote UE, the gNB may configure or modify the node that performs scheduling for the SL. For example, since the remote UE can send this information according to the radio wave propagation conditions and load conditions in the SL, the gNB can flexibly configure or modify the node that performs scheduling for the SL according to the radio wave propagation conditions and load conditions in the SL.

[0326] Another method is disclosed. Information regarding the configuration or modification of the scheduling node for the SL may be transmitted from the remote UE to the relay UE via the SL's RRC signaling, and the relay UE, upon receiving the information via the signaling, may transmit the information to the gNB via RRC signaling. In this way, the gNB can receive the information transmitted from the remote UE. This allows for flexible configuration or modification of the node that performs scheduling for the SL.

[0327] Another method is disclosed. The remote UE may send information regarding the configuration or modification of the scheduling node for the SL to the gNB via MAC signaling. The remote UE may also send this information in a MAC CE. The information may be sent from the remote UE to the relay UE via the SL's MAC signaling, and the relay UE, upon receiving the information via the signaling, may then send the information to the gNB via MAC signaling. In this way, the gNB can receive the information sent from the remote UE, allowing for flexible configuration of the node that performs scheduling for the SL. Furthermore, using MAC signaling enables early notification with a low error rate.

[0328] Another method is disclosed. The remote UE may transmit information regarding the configuration or modification of the scheduling node for the SL to the gNB via L1 / L2 signaling. This information may be transmitted from the remote UE to the relay UE via the SL's L1 / L2 signaling, and the relay UE, upon receiving the information via the signaling, transmits it to the gNB via L1 / L2 signaling. For example, the information may be included in the SCI and transmitted from the remote UE to the relay UE via the PSCCH, and the relay UE, upon receiving the information via the SCI, may include the information in the DCI and transmit it to the gNB via the PDCCH. In this way, the gNB can receive the information transmitted from the remote UE, allowing for flexible configuration or modification of the node performing scheduling for the SL. Furthermore, using L1 / L2 signaling enables earlier notification.

[0329] This document discloses a method by which a gNB performs scheduling for SL and scheduling for UL. The gNB transmits SL scheduling information to the remote UE. The gNB transmits UL scheduling information to the relay UE. The remote UE transmits SL scheduling information to the relay UE. The SL and UL scheduling information may be limited to communication between the remote UE and the gNB via the relay UE.

[0330] The SL scheduling information is scheduling information relating to communication from the remote UE to the relay UE in communication between the remote UE and the gNB via the relay UE. The SL scheduling information may also be information relating to the scheduling of SL control information and / or SL data and / or FB for SL data. The scheduling information for SL control information may, for example, be information relating to the PSCCH that transmits the SL control information. The scheduling information for SL control information may also be information relating to the PSSCH that transmits the SL control information. The scheduling information for SL data may also be information relating to the PSSCH that transmits the SL data. The scheduling information for SL FB may also be information relating to the scheduling of SL FB transmitted from the relay UE to the remote UE on the SL. The scheduling information for SL FB may also be information relating to the PSFCH that transmits the SL FB, and information relating to the timing of transmitting the SL FB. The scheduling information for SL FB may also be information relating to RRC signaling that transmits the SL FB from the remote UE to the gNB, and information relating to the timing of transmitting the FB. The information relating to the PSFCH may include, for example, information indicating the PSFCH setting. The SL's FB information may include, for example, HARQ FB information in the SL, CSI information in the SL, etc. The aforementioned information regarding PSCCH, PSSCH, and PSFCH may include, for example, resource allocation information for the CH.

[0331] If the PSFCH setting is notified via RRC signaling, an identifier may be assigned to the PSFCH setting, and the information regarding the scheduling of the SL's FB may include the identifier information of the PSFCH setting.

[0332] UL scheduling information is scheduling information related to communication from the relay UE to the gNB in ​​communication between the remote UE and the gNB via the relay UE. UL scheduling information may also be information related to the scheduling of UL data. Information related to the scheduling of UL data may include, for example, DL control information. Information related to the scheduling of UL data may include, for example, information about the PUSCH that transmits the UL data. The aforementioned information about the PUSCH may include, for example, resource allocation information for the CH.

[0333] The scheduling information for SL may include information indicating that it is for communication from a remote UE to a gNB via a relay UE. The scheduling information for SL may include information about the remote UE to which the relay communication will be performed. This information may, for example, be an identifier for the remote UE. The scheduling information for SL may include information about the relay UE that will perform the relay. This information may, for example, be an identifier for the relay UE. The scheduling information for UL may include information indicating that it is for communication from a remote UE to a gNB via a relay UE. The scheduling information for UL may include information about the remote UE to which the relay communication will be performed. This information may, for example, be an identifier for the remote UE. The scheduling information for UL may include information about the relay UE that will perform the relay. This information may, for example, be an identifier for the relay UE.

[0334] The remote UE may send scheduling information for the SL to the relay UE. The scheduling information for the SL may include information indicating that it is for communication from the remote UE to the gNB via the relay UE.

[0335] The scheduling information for SL and the scheduling information for UL may include information that links them together.

[0336] This document discloses a method for transmitting scheduling information for the Service Level (SL). The gNB transmits the SL scheduling information to the remote UE via RRC signaling. The gNB may also transmit this information by including it in an RRC message. In this way, the gNB can transmit this information to the remote UE.

[0337] Other transmission methods are disclosed. The gNB transmits scheduling information for the SL to the remote UE via MAC signaling. The gNB may also transmit this information in MAC CE. In this way, the gNB can transmit the information to the remote UE early and with a low error rate.

[0338] This document discloses a method for transmitting scheduling information for UL (Unit-Landing) systems. The gNB (Ground Blocker) notifies the relay UE (Unit-Effective) of the UL scheduling information via L1 / L2 signaling. The gNB may also transmit this information via PDCCH (Plan-Driven Convergence) by including it in the DCI (Data Control Indicator). This allows the gNB to transmit the information to the relay UE at an earlier stage. Furthermore, since the method of transmitting this information can be aligned with the conventional UL scheduling method, it is possible to avoid complicating the processing at the gNB and relay UE.

[0339] Other transmission methods are disclosed. The gNB transmits UL scheduling information to the relay UE via MAC signaling. The gNB may also transmit this information in MAC CE. In this way, the gNB can transmit the information to the relay UE early and with a low error rate.

[0340] Other transmission methods are disclosed. The gNB notifies the relay UE of UL scheduling information via RRC signaling. The gNB may also transmit this information in an RRC message. In this way, the gNB can transmit a large amount of information to the relay UE with a low error rate.

[0341] This document discloses a method for transmitting scheduling information for the Service Level (SL) from a relay UE to a remote UE. The relay UE transmits the SL scheduling information to the remote UE using the SL's L1 / L2 signaling. The relay UE may also transmit this information via PSCCH and / or PSSCH, including it in the SCI. This allows the relay UE to transmit the information to the remote UE earlier. Furthermore, since the method of transmitting this information can be aligned with the conventional SL scheduling method, it is possible to avoid complexity in processing at both the relay UE and the remote UE.

[0342] Another transmission method is disclosed. The relay UE transmits scheduling information for the SL to the remote UE via the SL's MAC signaling. The relay UE may also transmit this information in the SL's MAC CE. In this way, the relay UE can transmit the information to the remote UE early and with a low error rate.

[0343] Other transmission methods are disclosed. The relay UE notifies the remote UE of scheduling information for the SL using the SL's RRC signaling. The relay UE may also transmit this information in the SL's RRC message. In this way, the relay UE can transmit a large amount of information to the remote UE with a low error rate.

[0344] This document discloses a method for transmitting scheduling information for the Service Level (SL) from a remote UE to a relay UE. The remote UE transmits the SL scheduling information to the relay UE using the SL's L1 / L2 signaling. The remote UE may also transmit this information via PSCCH and / or PSSCH, including it in the SCI. This allows the remote UE to transmit the information to the relay UE earlier. Furthermore, since the method of transmitting this information can be aligned with the conventional SL scheduling method, it is possible to avoid complicating processing at both the remote UE and the relay UE.

[0345] Other transmission methods are disclosed. The remote UE transmits scheduling information for the SL to the relay UE via the SL's MAC signaling. The remote UE may also transmit this information in the SL's MAC CE. In this way, the remote UE can transmit the information to the relay UE early and with a low error rate. Other transmission methods are disclosed. The remote UE notifies the relay UE of scheduling information for the SL via the SL's RRC signaling. The remote UE may also transmit this information in the SL's RRC message. In this way, the remote UE can transmit a large amount of information to the relay UE with a low error rate.

[0346] Figure 30 is a sequence diagram showing an example of a scheduling method for communication from a remote UE to a gNB via a relay UE, in a modification 1 of Embodiment 3. In the example in Figure 30, the gNB performs SL scheduling from the remote UE to the relay UE for communication from the remote UE to the gNB via the relay UE. In step ST3001, the gNB transmits SL scheduling information to the remote UE. In the example in Figure 30, this information is transmitted using RRC signaling. Upon receiving the SL scheduling information, the remote UE transmits SL scheduling information to the relay UE in step ST3002 for transmitting uplink data, which is communication data to the gNB. The remote UE also uses this information to transmit communication data to the gNB to the relay UE in step ST3003. The SL scheduling information may also be transmitted along with the communication data. This information may be used by the relay UE to receive the communication data. In this way, the relay UE can receive communication data from the remote UE to the gNB.

[0347] In step ST3004, the relay UE transmits SL FB information to the remote UE. In the example in Figure 30, PSFCH is used for this transmission. The scheduling information for the SL FB information should be included in the SL scheduling information. In step ST3002 and / or step ST3003, the relay UE, having received the SL scheduling information, should use this information to transmit the SL FB information to the remote UE. In the example in Figure 30, the SL FB information is used as the Ack information for HARQ feedback. Upon receiving the Ack information, the remote UE transmits the SL FB information to the gNB in ​​step ST3005. In the example in Figure 30, RRC signaling is used for this transmission. In this way, the gNB can recognize that the relay UE has received the communication data from the remote UE to the gNB.

[0348] If the SL's FB information is Nack, the gNB should repeat the processing from step ST3001. In this way, the remote UE can perform the retransmission process of communication data from the remote UE to the relay UE.

[0349] In step ST3006, the gNB sends UL scheduling information to the relay UE. In the example in Figure 30, this information is notified via PDCCH. In step ST3007, the relay UE uses this information to send the communication data received from the remote UE to the gNB. In the example in Figure 30, the relay UE sends the communication data using PUSCH. If the gNB fails to receive the communication data from the relay UE in step ST3007, it may perform a retransmission process for the communication data on the UL. The gNB and relay UE may then repeat the process from step ST3006.

[0350] In this way, the remote UE can send communication data to the gNB via the relay UE. The gNB can then receive communication data from the remote UE.

[0351] Figure 31 is a sequence diagram showing another example of a scheduling method for communication from a remote UE to a gNB via a relay UE, in a modification 1 of Embodiment 3. In Figure 31, steps common to Figure 30 are given the same step numbers, and common explanations are omitted. The example in Figure 31 discloses a method in which the gNB transmits UL scheduling information to the relay UE before receiving SL FB information from the remote UE. After the gNB transmits SL scheduling information to the remote UE in step ST3001, it transmits UL scheduling information to the relay UE in step ST3006.

[0352] After executing steps ST3002 to ST3004 and receiving communication data from the remote UE, the relay UE transmits the communication data to the gNB in ​​step ST3007 using the UL scheduling information received in step ST3006. In this way, the relay UE can transmit the communication data received from the remote UE to the gNB at an early stage.

[0353] In step ST3005, the remote UE sends FB information for the SL to the gNB. By sending FB information for the SL from the remote UE to the gNB, the gNB can determine whether or not communication data has been sent from the remote UE to the relay UE on the SL. If no communication data has been sent on the SL, the gNB should perform scheduling for the SL again and perform retransmission processing. If communication data has been sent on the SL, the gNB should perform scheduling for the UL again and perform retransmission processing on the UL.

[0354] One or more scheduling information for SLs may be associated with one or more scheduling information for ULs. For example, communication data from a remote UE to a gNB may be scheduled in the SL by notifying multiple scheduling information for SLs, and then scheduled in the UL by notifying one scheduling information for ULs. This method is effective when the SL cannot secure sufficient wireless resources with a single scheduling, but the UL can secure sufficient wireless resources with a single scheduling.

[0355] Figure 32 is a sequence diagram showing another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, according to Modification 1 of Embodiment 3. In Figure 32, steps common to Figure 31 are given the same step numbers, and common explanations are omitted. The example in Figure 32 discloses a case where the relay UE fails to receive the initial SL data from the remote UE to the relay UE, and the remote UE retransmits the SL data.

[0356] In step ST3201, if a relay UE fails to receive communication data from the remote UE, it sends a Nack to the remote UE as SL FB information. If the gNB fails to receive communication data at the transmission timing from the relay UE based on the UL scheduling information sent in step ST3006, it may perform the SL scheduling process again with the remote UE. This eliminates the need for the remote UE to send SL FB information to the gNB, thus reducing the amount of signaling.

[0357] This approach enables scheduling of communication from the remote UE to the gNB in ​​communication between the remote UE and the gNB via the relay UE. Therefore, communication from the remote UE to the gNB via the relay UE becomes possible. Furthermore, scheduling that takes into account the SL's feedback rate (FB) becomes possible, thus improving communication quality.

[0358] This paper discloses an alternative method for scheduling communication between a remote UE and a gNB via a relay UE, specifically focusing on the differences from the method disclosed above.

[0359] The gNB performs scheduling for SL and UL. SL and UL scheduling may be performed separately. The gNB transmits SL scheduling information to the relay UE. The relay UE transmits SL scheduling information to the remote UE. The gNB transmits UL scheduling information to the relay UE. The remote UE transmits SL scheduling information to the relay UE. The SL and UL scheduling information may be limited to communication between the remote UE and the gNB via the relay UE.

[0360] The scheduling information for the SL may be appropriately applied to the scheduling information for the SL disclosed above. Among the scheduling information for the SL, the information regarding the scheduling of the SL's FB may be, for example, information regarding the scheduling of the SL's FB transmitted from the relay UE to the remote UE on the SL, or information regarding the scheduling of the SL's FB transmitted from the relay UE to the gNB on the UL. The information regarding the scheduling of the SL's FB on the SL may be, for example, information regarding the PSFCH that transmits the SL's FB on the SL, or information regarding the timing of transmitting the SL's FB. The information regarding the scheduling of the SL's FB on the UL may be, for example, information regarding the PUCCH that transmits the SL's FB on the UL, or information regarding the timing of transmitting the SL's FB. The information regarding the PUCCH may include, for example, information indicating the PUCCH setting. The SL's FB information may be, for example, HARQ FB information on the SL, CSI information on the SL, etc. The information regarding the PSCCH, PSSCH, PSFCH, and PUCCH mentioned above may include, for example, resource allocation information for the CH.

[0361] A UCI may be provided on the UL for sending SL's FB. SL's FB information may also be included. A PUCCH setting for sending the FB on the UL may be notified via RRC signaling. In this case, an identifier may be provided for the PUCCH setting, and the identifier information for the PUCCH setting may be included as information regarding the scheduling of the FB as described above.

[0362] For UL scheduling, the UL scheduling information disclosed above should be applied as appropriate.

[0363] This document discloses a method for transmitting scheduling information for SL. The gNB notifies the relay UE of the SL scheduling information via L1 / L2 signaling. The gNB may also transmit this information via PDCCH by including it in the DCI. This allows the gNB to transmit the information to the relay UE earlier. Furthermore, since the method of transmitting this information can be aligned with the conventional DL and UL scheduling methods, it is possible to avoid complicating the processing at the gNB and relay UE.

[0364] Other transmission methods are disclosed. The gNB transmits scheduling information for the SL to the relay UE via MAC signaling. The gNB may also transmit this information in MAC CE. In this way, the gNB can transmit the information to the relay UE early and with a low error rate.

[0365] Other transmission methods are disclosed. The gNB notifies the relay UE of scheduling information for the SL via RRC signaling. The gNB may also transmit this information in an RRC message. In this way, the gNB can transmit a large amount of information to the relay UE with a low error rate.

[0366] Regarding the method for transmitting scheduling information for UL, the method disclosed above should be applied as appropriate.

[0367] Similar to the method disclosed in Embodiment 3, an RNTI for relay communication may be provided. For example, it may be called Relay-RNTI. Relay-RNTI can identify PDCCHs that contain SL scheduling information and / or UL scheduling information for relay communication, or PDCCHs that schedule MAC signaling containing such information, or PDCCHs that schedule RRC signaling containing such information. For example, these PDCCHs may be masked with Relay-RNTI. In this way, the relay UE can recognize early on that the information is SL scheduling information and / or UL scheduling information for relay communication.

[0368] Alternatively, a PDCCH containing SL scheduling information and / or UL scheduling information for relay communication, or a PDCCH scheduling MAC signaling containing such information, or a PDCCH scheduling RRC signaling containing such information, can be identified using an RNTI for identifying the remote UE, such as a C-RNTI. For example, these PDCCHs can be masked with the remote UE's C-RNTI. In this way, the relay UE can recognize early on that the information contains SL scheduling information and / or DL ​​scheduling information for relay communication to the remote UE.

[0369] Regarding the method for transmitting scheduling information for SL from the relay UE to the remote UE, the method disclosed above should be applied as appropriate.

[0370] Regarding the method for transmitting scheduling information for SL from the remote UE to the relay UE, the method disclosed above should be applied as appropriate.

[0371] Figure 33 is a sequence diagram showing another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, according to Modification 1 of Embodiment 3. In Figure 33, steps common to Figure 30 are given the same step numbers, and common explanations are omitted. In the example in Figure 33, the gNB transmits SL scheduling information to the relay UE, and the relay UE, upon receiving this information, transmits SL scheduling information to the remote UE.

[0372] In the example shown in Figure 33, the gNB performs SL scheduling from the remote UE to the relay UE in communication from the remote UE to the gNB via the relay UE. In step ST3301, the gNB transmits SL scheduling information to the relay UE. In step ST3302, the relay UE notifies the remote UE of the SL scheduling information it received from the gNB. Upon receiving the SL scheduling information from the relay UE, the remote UE may then perform the process of transmitting communication data to the gNB in ​​step ST3002.

[0373] Upon receiving the SL's FB information from the relay UE in step ST3004, the remote UE transmits the SL's FB information to the relay UE in step ST3303. In the example in Figure 33, this is transmitted as PSCCH. Upon receiving the SL's FB information, the relay UE transmits the SL's FB information to the gNB in ​​step ST3304. In the example in Figure 33, this is transmitted as PUCCH. In this way, the gNB can recognize that the relay UE has received communication data from the remote UE to the gNB. Upon receiving the SL's FB information in step ST3304, the gNB may perform UL scheduling for the transmission of the communication data to the relay UE.

[0374] In this way, the remote UE can send communication data to the gNB via the relay UE. The gNB can then receive communication data from the remote UE.

[0375] Figure 34 is a sequence diagram showing another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in a modification 1 of Embodiment 3. In Figure 34, steps common to Figure 33 are given the same step numbers, and common explanations are omitted. The example in Figure 34 discloses the case where the relay UE fails to receive SL data from the remote UE to the relay UE.

[0376] Figure 34 shows a case where the relay UE cannot receive the SL data, which is the communication data sent from the remote UE to the gNB, in step ST3003. If the relay UE could not receive the communication data from the remote UE to the gNB, in step ST3401, it sends a Nack to the remote UE as FB information for the SL. In step ST3402, the remote UE sends a Nack to the relay UE as FB information for the SL. If the relay UE receives a Nack from the remote UE, in step ST3403, it sends a Nack to the gNB as FB information for the SL. In this way, the gNB can recognize that the relay UE could not receive the communication data from the remote UE to the gNB.

[0377] When the gNB receives a Nack from the relay UE as FB information for the SL, it should perform the SL scheduling process again in step ST3301 and send the SL scheduling information to the relay UE. This way, even if the transmission and reception of communication data on the SL fails, retransmission can be performed.

[0378] This approach enables scheduling of communication from the remote UE to the gNB in ​​communication between the remote UE and the gNB via the relay UE. Therefore, communication from the remote UE to the gNB via the relay UE becomes possible. Furthermore, scheduling that considers the SL's feedback rate (FB) becomes possible, improving communication quality. Additionally, by providing a UCI for SL FB information transmitted from the relay UE to the gNB on the UL, the occurrence of malfunctions in the relay UE can be reduced. Moreover, when using L1 / L2 signaling for SL scheduling from the gNB to the relay UE, earlier scheduling becomes possible, improving low-latency characteristics.

[0379] This paper discloses an alternative method for scheduling communication between a remote UE and a gNB via a relay UE, specifically focusing on the differences from the method disclosed above.

[0380] In this alternative method, the gNB performs scheduling for both SL and UL together. The gNB transmits scheduling information for both SL and UL to the relay UE. The relay UE, having received the scheduling information for both SL and UL from the gNB, transmits the scheduling information for SL to the remote UE. The remote UE transmits the scheduling information for SL to the relay UE. The scheduling information for both SL and UL may be limited to communication between the remote UE and the gNB via the relay UE.

[0381] In the other method, scheduling information for SL and UL may be appropriately applied to the scheduling information for SL and scheduling information for UL disclosed above.

[0382] An offset may be provided between the SL scheduling information transmission timing and / or SL data transmission timing and the UL data transmission timing. Alternatively, instead of the SL scheduling information transmission timing and / or SL data transmission timing, it may be the SL scheduling information reception timing and / or SL data reception timing. Information regarding the offset may be included in the SL scheduling information or UL scheduling information in the other method. By receiving this information, the relay UE can recognize the UL data transmission timing after receiving the SL data. In this way, the amount of UL scheduling information can be reduced.

[0383] This invention discloses a method for transmitting scheduling information for SL and UL in an alternative manner. The gNB transmits scheduling information for SL and UL to the relay UE via L1 / L2 signaling. This information may be included in a single DCI and transmitted via PDCCH. A separate DCI may be provided for the relay. The information may also be included in the relay's DCI and transmitted via PDCCH. By transmitting the scheduling information for SL and UL together in this way, the amount of signaling can be reduced. In addition, the gNB can transmit this information to the relay UE earlier. Furthermore, since the method of transmitting this information can be aligned with the conventional DL and UL scheduling methods, it is possible to avoid complexity in the processing at the gNB and relay UE.

[0384] Other transmission methods are disclosed. The gNB transmits scheduling information for SL and UL to the relay UE via MAC signaling. The gNB may transmit this information in a single MAC CE. A MAC CE for relays may be provided. The gNB may transmit this information in the MAC CE for relays. This reduces the amount of signaling. In addition, the gNB can transmit this information to the relay UE early and with a low error rate.

[0385] Other transmission methods are disclosed. The gNB transmits scheduling information for SL and UL to the relay UE via RRC signaling. The gNB may transmit this information in a single RRC message. A separate RRC message for relays may be provided. The gNB may transmit this information in the relay RRC message. In this way, the gNB can transmit a large amount of information to the relay UE with a low error rate.

[0386] Regarding the method for transmitting scheduling information for SL from the relay UE to the remote UE, the method disclosed above should be applied as appropriate.

[0387] Regarding the method for transmitting scheduling information for SL from the remote UE to the relay UE, the method disclosed above should be applied as appropriate.

[0388] Figure 35 is a sequence diagram showing another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in a modification 1 of Embodiment 3. In Figure 35, steps common to Figure 33 are given the same step numbers, and common explanations are omitted. In the example in Figure 35, the gNB transmits scheduling information for both SL and UL to the relay UE.

[0389] In the example shown in Figure 35, the gNB performs scheduling for both SL and UL. For example, in UL scheduling, the time required for retransmission of SL data and the maximum number of retransmissions may be considered. In step ST3501, the gNB transmits the SL scheduling information and the UL scheduling information to the relay UE. In the example shown in Figure 35, this information is notified via a single PDCCH. Alternatively, this information could be included in a single DCI and notified via the PDCCH. This reduces the amount of signaling required.

[0390] Furthermore, in the example shown in Figure 35, the gNB transmits UL scheduling information to the relay UE along with SL scheduling information. Therefore, the relay UE can immediately transmit the communication data to the gNB using the UL scheduling information after receiving the communication data from the remote UE to the gNB. In other words, low-latency characteristics can be improved in communication from the remote UE to the gNB via the relay UE.

[0391] As disclosed above, one or more SL scheduling information may be associated with one or more UL scheduling information. The same effects as when applying the method disclosed above can be obtained.

[0392] Figure 36 is a sequence diagram showing another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in a modification 1 of Embodiment 3. In Figure 36, steps common to Figure 35 are given the same step numbers, and common explanations are omitted. The example in Figure 36 discloses the case where the relay UE fails to receive SL data from the remote UE.

[0393] Figure 36 shows a case where the relay UE cannot receive the SL data, which is communication data sent from the remote UE to the gNB, in step ST3003. If the relay UE could not receive the communication data sent from the remote UE to the gNB in ​​step ST3003, it sends a Nack to the remote UE as FB information for the SL in step ST3401. If the gNB could not receive the communication data at the transmission timing from the relay UE based on the UL scheduling information sent in step ST3501, it is advisable to perform SL scheduling and UL scheduling again with the remote UE and send the SL scheduling information and UL scheduling information to the relay UE. In this way, it is possible to eliminate the need to send SL FB information from the remote UE to the gNB. In other words, the amount of signaling can be reduced.

[0394] The relay UE may use the UL scheduling information received in step ST3501 to send UL data to another gNB instead of UL data from the remote UE to the gNB. For example, if the relay UE is unable to receive SL data from the remote UE, it will send other UL data to the gNB. This improves the efficiency of radio resource utilization for sending UL data from the remote UE to the gNB.

[0395] In step ST3401, a remote UE that receives a Nack as FB information for the SL may add 1 to the SL retransmission count. This allows retransmission up to the maximum number of SL retries. In step ST3402, a relay UE that receives a Nack as FB information for the SL may add 1 to the UL retransmission count. This allows retransmission up to the maximum number of UL retries. In this case, UL retransmission is possible up to the maximum number of UL retries, including the number of SL retries. Alternatively, in step ST3402, a relay UE that receives a Nack as FB information for the SL may not add 1 to the UL retransmission count. This allows retransmission up to the maximum number of UL retries. In this case, UL retransmission is possible up to the maximum number of UL retries, without including the number of SL retries. This is effective when you want to improve the success rate of sending and receiving with UL.

[0396] The maximum number of SL retransmissions and the maximum number of UL retransmissions may be set individually. This allows for flexible settings for SL and UL. The maximum number of SL retransmissions and the maximum number of UL retransmissions may be the same. They may be set as a single maximum number of retransmissions. This makes retransmission processing easier. The maximum number of SL retransmissions and the maximum number of UL retransmissions may be statically determined by standards, etc. Alternatively, the gNB may set them. The gNB's RRC may set them. If the gNB has a CU and DU separation configuration, the gNB's CU may set them and notify the DU. The gNB sends the set maximum number of SL retransmissions to the remote UE. The gNB sends the set maximum number of UL retransmissions to the relay UE. The remote UE and relay UE can set the maximum number of retransmissions by receiving the retransmission count from the gNB. Since the number of retransmissions can be limited, the efficiency of wireless resource utilization can be improved.

[0397] In this way, by performing scheduling for both SL and UL together, the amount of signaling can be reduced. Furthermore, since the UL scheduling information is notified to the relay UE along with the SL scheduling information, the relay UE can immediately use the UL scheduling information to transmit the SL data received from the remote UE as UL data to the gNB after receiving SL data from the remote UE. This enables early communication from the remote UE to the gNB via the relay UE, resulting in lower latency. In addition, by providing a DCI for the relay, it becomes possible to set both SL and UL scheduling information in a single DCI, thereby reducing the occurrence of malfunctions in communication from the remote UE to the gNB via the relay UE.

[0398] This paper discloses an alternative method for scheduling communication between a remote UE and a gNB via a relay UE, specifically focusing on the differences from the method disclosed above.

[0399] In this alternative method, the relay UE transmits the SL's FB and UL data together to the gNB. The SL's FB and UL data may be limited to communication between the remote UE and the gNB via the relay UE.

[0400] In this alternative method, scheduling information for transmitting SL FB information and UL data together may be included as scheduling information for SL and / or scheduling information for UL. Information combining SL FB information and UL data may be used as UL information for relay. Scheduling information for relay UL information may include, for example, information about the PUSCH that transmits the information on the UL, and information about the timing of transmitting the information on the UL. Information about the PUSCH may include, for example, resource allocation information for the CH.

[0401] If the SL's FB information is an Ack for HARQ feedback, it may be unnecessary to send the SL's FB information on the UL. The relay UE may send only UL data to the gNB. The gNB can recognize that the SL data has reached the relay UE by receiving the UL data from the relay UE.

[0402] The gNB does not need to send the scheduling information for transmitting SL FB information on the UL to the relay UE. For example, it does not need to send the scheduling information for PUCCH for transmitting SL FB information on the UL. In the method described above, the relay UE sends the SL FB information to the gNB together with the UL data. By using this method, scheduling for SL FB information transmitted by the relay UE on the UL becomes unnecessary.

[0403] Aside from the SL's FB information and the UL data's scheduling information, the SL and UL scheduling information disclosed above should be applied as appropriate.

[0404] The method for transmitting scheduling information for SL and UL should be appropriately applied using the method disclosed above. The same effect as the method disclosed above can be obtained.

[0405] Regarding the method for transmitting scheduling information for SL from the relay UE to the remote UE, the method disclosed above should be applied as appropriate.

[0406] Regarding the method for transmitting scheduling information for SL from the remote UE to the relay UE, the method disclosed above should be applied as appropriate.

[0407] Figure 37 is a sequence diagram showing another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in a modification 1 of Embodiment 3. In Figure 37, steps common to Figure 35 are given the same step numbers, and common explanations are omitted. In the example in Figure 37, the relay UE transmits the UL data and SL FB information to the gNB in ​​a single PUSCH.

[0408] In step ST3303, the relay UE receives the SL's FB information from the remote UE. In step ST3701, the relay UE transmits the SL's FB information to the gNB along with the communication data from the remote UE to the gNB. In the example in Figure 37, the SL's FB information and the communication data are transmitted in a single push in step ST3701. This allows the gNB to recognize that the relay UE has received the communication data from the remote UE, and enables the gNB to receive the communication data from the remote UE.

[0409] In this way, the remote UE can send communication data to the gNB via the relay UE. The gNB can then receive communication data from the remote UE.

[0410] Figure 38 is a sequence diagram showing another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, in a modification 1 of Embodiment 3. In Figure 38, steps common to Figure 36 or 37 are given the same step numbers, and common explanations are omitted. The example in Figure 38 discloses the case where the relay UE fails to receive SL data from the remote UE to the relay UE.

[0411] In the example in Figure 38, similar to the example in Figure 36 mentioned above, it shows a case where the relay UE cannot receive the SL data, which is communication data sent from the remote UE to the gNB, in step ST3003. In step ST3402, the relay UE receives a Nack from the remote UE as FB information for the SL, and in step ST3403, it sends a Nack to the gNB as FB information for the SL. In this case, since the relay UE has not received the communication data from the remote UE, it sends only the FB information for the SL to the gNB. In the example in Figure 38, this information is sent using PUSCH. The gNB, having received a Nack from the relay UE as FB information for the SL, should again perform scheduling for the SL and scheduling for the UL for the relay UE, and in step ST3501, send the scheduling information for the SL and scheduling information for the UL to the relay UE. Subsequently, in step ST3404, the relay UE receives the communication data from the remote UE to the gNB as SL data, and in step ST3701, it sends the FB information for the SL to the gNB together with the communication data from the remote UE to the gNB. This approach allows for retransmission even if there is a failure in sending or receiving communication data on the SL (Service Level).

[0412] In this way, transmitting the SL's FB information and UL data together reduces the amount of signaling required. Furthermore, the relay UE no longer needs to send the SL's FB information and DL data separately to the gNB, thus reducing the relay UE's transmission power. Additionally, since the relay UE no longer needs to send the SL's FB information and DL data separately to the gNB, the occurrence of malfunctions in the relay UE can be reduced.

[0413] Depending on the type of FB information of the SL, the channel used to transmit the SL's FB information on the UL may be different. In this case, the gNB should send scheduling information for the UL data and scheduling information for transmitting the SL's FB information on the UL to the relay UE. For example, the gNB may send scheduling information for the PUSCH channel for transmitting the UL data and scheduling information for the PUCCH channel for transmitting the SL's FB information on the UL to the relay UE.

[0414] For example, if the SL's FB information is an Ack for HARQ feedback, the SL's FB information may be sent via PUSCH on the UL, and if it is a Nack, the SL's FB information may be sent via PUCCH on the UL. In the case of an Ack, the UL data and the SL's FB information may be sent via a single PUSCH on the UL. For example, if the SL's FB information is CSI information, the SL's FB information may be sent via PUSCH on the UL. The UL data and the SL's FB information may be sent via a single PUSCH on the UL.

[0415] In this way, for example, the gNB can determine the type of SL's FB information based on which channel it received from the relay UE. Also, for example, if the SL's FB information is Nack, no UL data is generated on the UL. Therefore, when the SL's FB information is Nack, transmission using PUCCH on the UL allows for transmission with a small amount of radio resources. Also, for example, when the SL's FB information is CSI information, transmission using PUSCH on the UL allows for the transmission of a large amount of CSI information. In this way, the efficiency of radio resource utilization can be improved.

[0416] This paper discloses an alternative method for scheduling communication between a remote UE and a gNB via a relay UE, specifically focusing on the differences from the method disclosed above.

[0417] In the method disclosed above, the remote UE transmitted the SL's FB information to the relay UE. This enabled the remote UE to transmit the SL's FB information to the gNB. Alternatively, the remote UE does not need to transmit the SL's FB information to the relay UE. In this alternative method, the relay UE notifies the gNB of the SL's FB information. The relay UE is aware of the SL's FB information in the SL communication from the remote UE to the relay UE. Or, the relay UE generates the SL's FB information itself. Therefore, the relay UE can notify the gNB of the SL's FB information without receiving it from the remote UE.

[0418] In this alternative method, the gNB does not transmit information regarding the scheduling of the SL's Facebook bridge to the relay UE as scheduling information for the SL. The relay UE does not transmit information regarding the scheduling of the SL's Facebook bridge to the remote UE as scheduling information for the SL. This makes it possible to reduce the amount of scheduling information for the SL.

[0419] Figure 39 is a sequence diagram showing another example of a method for scheduling communication from a remote UE to a gNB via a relay UE, for a modification 1 of Embodiment 3. In Figure 39, steps common to Figure 37 are given the same step numbers, and common explanations are omitted. In the example of Figure 39, the remote UE does not transmit SL FB information to the relay UE. That is, the remote UE does not perform step ST3303 in the example of Figure 37 described above. The relay UE transmits SL FB information to the gNB.

[0420] In step ST3004, the remote UE, having received FB information for the SL from the relay UE, does not transmit the FB information for the SL to the relay UE. In step ST3003, the relay UE can determine whether or not it has received communication data from the remote UE to the gNB. The relay UE may transmit the FB information for the SL to the gNB in ​​step ST3701 without receiving the FB information for the SL from the remote UE. In this method, in step ST3901, the gNB does not need to transmit scheduling information for the SL from the remote UE to the relay UE. This reduces the amount of signaling and the amount of information transmitted.

[0421] Figure 40 is a sequence diagram showing another example of a scheduling method for communication from a remote UE to a gNB via a relay UE, in a modification 1 of Embodiment 3. In Figure 40, steps common to Figure 38 or 39 are given the same step numbers, and common explanations are omitted. The example in Figure 40 discloses the case where the relay UE fails to receive SL data from the remote UE. It also discloses the case where different channels are used on the UL to transmit FB information for SL depending on the type of FB information for SL.

[0422] In the example in Figure 40, if the SL's FB information is an Ack in HARQ feedback, PUSCH is used to transmit the SL's FB information from the relay UE to the gNB, and if it is a Nack, PUCCH is used. In step ST3901, the gNB transmits scheduling information for both the SL and UL to the relay UE. At this time, the scheduling information for the SL may include information about the channel on which the SL's FB information is transmitted, specifically information about PUSCH and PUCCH in Figure 40, within the scheduling information for the SL's FB. It is also possible to include information in the scheduling information that associates the type of SL's FB information with the channel on which the FB information is transmitted. In this way, on the UL, transmission is possible using PUSCH for Ack and PUCCH for Nack.

[0423] In step ST3003, if the relay UE failed to receive the communication data transmitted by the remote UE, in step ST3304, it sends a Nack to the gNB via PUCCH as SL FB information. This does not include the communication data from the remote UE to the gNB. Upon receiving the Nack as SL FB information from the relay UE, the gNB sends scheduling information for retransmission of SL and UL to the relay UE in step ST3901. This initiates the retransmission process of the communication data from the remote UE to the gNB. In step ST3404, the relay UE receives the retransmitted communication data from the remote UE and, in step ST3701, sends an Ack to the gNB as SL FB information along with the communication data from the remote UE to the gNB via PUSCH. The gNB can then receive the communication data from the remote UE along with the SL FB information. In this way, the relay UE can transmit SL FB information to the gNB using the appropriate CH according to the type of SL FB information.

[0424] Furthermore, in the example in Figure 40, the notification of SL FB information from the remote UE to the relay UE is omitted. In other words, in the example in Figure 40, steps ST3402 and ST3303, which are included in the example in Figure 38, are omitted.

[0425] In this way, by eliminating the transmission of SL FB information from the remote UE to the relay UE, the amount of signaling can be reduced. Also, since the relay UE will transmit the SL FB information to the gNB, the SL FB information can be notified to the gNB earlier. In other words, the low latency characteristics of communication from the remote UE to the gNB via the relay UE can be improved.

[0426] Modification 2 of Embodiment 3. This paper discloses an alternative method for scheduling SLs between a remote UE and a relay UE in communication between a remote UE and a gNB via a relay UE. The main differences from the method disclosed above are disclosed here.

[0427] This document discloses a method for scheduling SL (Service Level) from a relay UE to a remote UE in communication from a gNB (glue-based network) to a remote UE via a relay UE. In this modified example 2, the gNB performs SL scheduling on the relay UE prior to the generation of communication data to the remote UE. In the communication system according to this modified example 2, once SL scheduling is set, the setting of SL scheduling is maintained until the SL scheduling is changed or released. For example, the resource allocation of the CH (channel) that transmits SL scheduling information is maintained until the resource allocation is changed or released.

[0428] If the scheduling for the SL is changed, the settings for the SL will remain in place until the SL scheduling is changed again or released. If the SL scheduling is released, the settings for the SL scheduling will be released. The change may be part of the SL scheduling information or all of it.

[0429] The SL scheduling may be performed using RRC signaling. It may also be performed using RRC reconfiguration messages. The gNB transmits SL scheduling information to the relay UE in advance of the generation of communication data to the remote UE. When the relay UE receives the SL scheduling information from the gNB, and communication data is generated from the gNB to the remote UE via the relay UE—in other words, when the relay UE receives the communication data from the gNB—it transmits the communication data to the remote UE using the previously received SL scheduling information.

[0430] The scheduling information for SL may be appropriately applied using the scheduling information for SL disclosed in Embodiment 3. In the scheduling information for SL, the transmission timing of SL control information and / or SL data and / or SL FB may be periodic. This period may be included in the scheduling information for SL in advance and notified. Here, although it is written as transmission timing, it may also be called transmission-enabled timing. In this modified example 2, scheduling is performed before the generation of communication data, so it is preferable that this period indicates the transmission-enabled timing.

[0431] In this way, even if the timing of communication data generation is after the notification of scheduling information for SL, the periodically scheduled resources can be used to transmit the communication data. The periods may be different for each piece of information. For example, the transmission period for SL control information may be longer than the transmission period for SL data. For example, twice as long. In this case, one SL control information resource becomes available for transmission to two SL data resources. Two SL data sets may be controlled using one piece of SL control information. In this way, communication control can be made easier.

[0432] As previously disclosed, if the relay UE receives scheduling information for the SL from the gNB in ​​advance, it uses that scheduling information. Another method is disclosed. Information may be provided to start / stop (Activation / Deactivation) operations using the previously transmitted SL scheduling information.

[0433] For example, a gNB transmits SL scheduling operation information when it starts using pre-transmitted SL scheduling information, and transmits SL scheduling stop information when it stops using the pre-transmitted SL scheduling information. When a relay UE receives SL scheduling operation information from a gNB, it starts using the pre-transmitted SL scheduling information, and when it receives SL scheduling stop information, it stops using the pre-transmitted SL scheduling information. In this way, when pre-transmitted SL scheduling information is not being used, the radio resources allocated by that SL scheduling information become available for other uses. In other words, it becomes possible to improve the efficiency of radio resource utilization.

[0434] This approach allows for more flexible scheduling of SL (Service Level) from the relay UE to the remote UE in communication from the gNB (Golden Network Interface) via the relay UE to the remote UE, resulting in benefits such as reduced signaling volume, improved wireless resource utilization efficiency, and avoidance of increased complexity in communication processing.

[0435] This document discloses a method for scheduling SL (Streaming Limit) from a remote UE to a gNB (GangnamBridge) via a relay UE. In this method, the gNB performs SL scheduling for the remote UE. The gNB does not necessarily have to receive a Scheduling Request (SR) due to communication data generation at the remote UE. Once SL scheduling is set, the remote UE continues to maintain the SL scheduling until it is changed or released. For example, the resource allocation of a channel that transmits SL scheduling information will continue to be set until the resource allocation is changed or released.

[0436] If the scheduling for the SL is changed, the settings for the SL will remain in place until the SL scheduling is changed again or released. If the SL scheduling is released, the settings for the SL scheduling will be released. The change may be part of the SL scheduling information or all of it.

[0437] The SL scheduling may be performed using RRC signaling. It may also be performed using RRC reconfiguration messages. The gNB transmits SL scheduling information to the remote UE using RRC signaling. When a remote UE receives SL scheduling information from the gNB and communication data is generated from the remote UE to the gNB via the relay UE, the remote UE uses the SL scheduling information to transmit the communication data to the relay UE.

[0438] Alternatively, the gNB may transmit SL scheduling information to the relay UE via RRC signaling, and the relay UE, upon receiving the RRC signaling, may then transmit SL scheduling information to the remote UE using the SL's RRC signaling. This method is also applicable when the relay UE relays the RRC signaling.

[0439] For SL scheduling information, the SL scheduling information disclosed in Modification 1 of Embodiment 3 may be applied as appropriate. In SL scheduling information, the transmission timing of SL control information and / or SL data and / or SL FB may be periodic. This period may be included in the SL scheduling information in advance and notified. Here, although it is written as transmission timing, it may also be called transmission-enabled timing. Since scheduling is performed before the generation of communication data, it is preferable that this period indicates the transmission-enabled timing.

[0440] In this way, even if the timing of communication data generation is after the notification of scheduling information for SL, the periodically scheduled resources can be used to transmit the communication data. The periods may be different for each piece of information. For example, the transmission period for SL control information may be longer than the transmission period for SL data. In this way, communication control can be made easier.

[0441] As previously disclosed, when a remote UE receives scheduling information for the SL from a gNB, it uses that scheduling information. Another method is disclosed. Information may be provided to start / stop (Activation / Deactivation) operations using the transmitted SL scheduling information.

[0442] For example, the gNB transmits SL scheduling operation information when it starts using SL scheduling information. The gNB transmits SL scheduling stop information when it stops using SL scheduling information. The remote UE starts using SL scheduling information when it receives SL scheduling operation information from the gNB, and stops using SL scheduling information when it receives SL scheduling stop information. In this way, when no communication data is generated at the remote UE and SL scheduling information is not being used, the wireless resources allocated by that SL scheduling information become available for other purposes. In other words, it becomes possible to improve the efficiency of wireless resource utilization.

[0443] This document discloses a method for notifying SL scheduling operation / stop information. The gNB notifies the relay UE of SL scheduling operation / stop information via L1 / L2 signaling. The gNB may also include this information in the DCI and transmit it via PDCCH. This allows the gNB to transmit the information to the relay UE at an earlier stage.

[0444] Other transmission methods are disclosed. The gNB transmits scheduling operation / stop information for the SL to the relay UE via MAC signaling. The gNB may also transmit this information in MAC CE. In this way, the gNB can transmit the information to the relay UE early and with a low error rate.

[0445] Other transmission methods are disclosed. The gNB notifies the relay UE of scheduling operation / stop information for SL via RRC signaling. The gNB may also include this information in an RRC message and transmit it. In this way, the gNB can transmit a large amount of information to the relay UE with a low error rate.

[0446] This document discloses a method for transmitting scheduling operation / stop information for the SL from a relay UE to a remote UE. The relay UE transmits the scheduling operation / stop information for the SL to the remote UE using the SL's L1 / L2 signaling. The relay UE may also include this information in the SCI and transmit it via PSCCH and / or PSSCH. This allows the relay UE to transmit the information to the remote UE at an earlier stage.

[0447] Another transmission method is disclosed. The relay UE transmits scheduling operation / stop information for the SL to the remote UE via the SL's MAC signaling. The relay UE may also transmit this information in the SL's MAC CE. In this way, the relay UE can transmit the information to the remote UE early and with a low error rate.

[0448] Other transmission methods are disclosed. The relay UE notifies the remote UE of scheduling operation / stop information for the SL using the SL's RRC signaling. The relay UE may also transmit this information in the SL's RRC message. In this way, the relay UE can transmit a large amount of information to the remote UE with a low error rate.

[0449] This approach allows for more flexible scheduling of SLs from the remote UE to the relay UE in communication from the remote UE to the gNB via the relay UE, resulting in benefits such as reduced signaling volume, improved wireless resource utilization efficiency, and avoidance of increased communication processing complexity.

[0450] The above describes a method for scheduling SL (Single Line) from a remote UE to a gNB (Global Network Boundary) via a relay UE. The method disclosed above may also be applied to scheduling UL (Unified Line) from a relay UE to a gNB in ​​communication from a remote UE to a gNB via a relay UE. In addition, UL scheduling operation / stop information may be provided. The method for notifying the UL scheduling information and / or UL scheduling operation / stop information from the gNB to the relay UE may be appropriately applied using the method disclosed in Modification 1 of Embodiment 3. By doing so, scheduling UL from a relay UE to a gNB in ​​communication from a remote UE to a gNB via a relay UE can be made more flexible, and effects such as reduction of signaling amount, improvement of wireless resource utilization efficiency, and avoidance of complexity in communication processing can be obtained.

[0451] The above describes a method for scheduling SL (Streamlined Line) from a remote UE to a relay UE in communication from a remote UE to a gNB via a relay UE. The method disclosed above may also be applied to scheduling DL (Downloadable Line) from a gNB to a relay UE in communication from a gNB to a remote UE via a relay UE. Information for starting / stopping the DL scheduling operation may also be provided. The method for notifying the DL scheduling information and / or the information for starting / stopping the DL scheduling operation from the gNB to the relay UE may be the method disclosed in Embodiment 3 as appropriate. By doing so, DL scheduling from the gNB to the relay UE in communication from a gNB to a remote UE via a relay UE can be made more flexible, and effects such as reducing the amount of signaling, improving the efficiency of wireless resource utilization, and avoiding complexity in communication processing can be obtained.

[0452] The scheduling method for SL and the scheduling method for UL disclosed above may be applied in appropriate combinations. In the relay UE, the scheduling method for SL and the scheduling method for UL may be combined to schedule so that the timing of receiving from the remote UE and the timing of transmitting to the gNB fall within a predetermined period. The predetermined period may be set to take into account the relay processing time at the relay UE. In this way, the relay UE that receives communication data from the remote UE can transmit the communication data to the gNB as soon as possible after the relay processing time.

[0453] By using the method disclosed in Modification 2 of this Embodiment 3, scheduling in communication between the remote UE and the gNB via the relay UE can be made more flexible, resulting in effects such as a reduction in signaling volume, improved efficiency of wireless resource utilization, and avoidance of increased complexity in communication processing. Furthermore, when communication data is generated at the gNB or remote UE, the remote UE or relay UE can transmit the communication data with low latency. In other words, the low-latency characteristics of communication between the remote UE and the gNB via the relay UE can be improved.

[0454] Modification 3 of Embodiment 3. The methods disclosed in Embodiment 3 to Modification 2 of Embodiment 3 are not limited to a single remote UE connected to the relay UE. They may also be applied when multiple remote UEs connect to the gNB via a single relay UE. The methods disclosed above can be appropriately applied to the communication between each remote UE and the gNB via the relay UE. The same effects as those disclosed above can be obtained.

[0455] Modification 3 of this embodiment 3 discloses an alternative method for the case where multiple remote UEs are connected to a gNB via a single relay UE.

[0456] This document discloses a scheduling method for communication from the gNB towards the remote UE in communication between the remote UE and the gNB via a relay UE. The gNB individually performs scheduling for SL between the relay UE and each remote UE. The gNB performs one DL scheduling for multiple remote UEs. One DL scheduling piece is shared for communication to multiple remote UEs. The SL scheduling information and DL scheduling information may be appropriately applied to the same information as that applied to the method disclosed in Embodiment 3 to Modification 2 of Embodiment 3 described above.

[0457] In this method, the gNB transmits scheduling information for SL (Service Level) to each remote UE and scheduling information for one DL (Delay Level) to the relay UE. The gNB attaches information identifying the destination remote UE to the communication data for each remote UE. For example, this identification information may be included in the MAC CE (Machine Message Encoder). The gNB may attach the MAC CE containing this identification information to the communication data for each remote UE and transmit it. In this way, the relay UE can recognize which remote UE the communication data received from the gNB is destined for. This method may also be applied when there is only one remote UE. The same effect can be obtained in this case as well.

[0458] A relay UE, having received DL scheduling information from the gNB, receives communication data for each remote UE using a single DL scheduling piece. In this way, the relay UE can receive communication data from the gNB destined for each remote UE.

[0459] A relay UE that receives SL scheduling information from a gNB transmits the SL scheduling information and communication data to each remote UE. The method for transmitting DL scheduling information, SL scheduling information, communication data, etc., may be appropriately applied using the method disclosed above. In this way, the relay UE is able to transmit communication data to each remote UE. In addition, each remote UE is able to receive communication data from the relay UE.

[0460] Another method for scheduling for SLs is disclosed. The gNB performs a single SL scheduling for multiple remote UEs. The single SL scheduling information is shared for communication with multiple remote UEs. The SL scheduling information to be combined may be part of or all of the aforementioned SL scheduling information.

[0461] In this alternative method, the gNB transmits a single SL scheduling information to the relay UE. The relay UE, upon receiving the SL scheduling information, uses it to transmit communication data to each remote UE. The relay UE attaches information identifying the destination remote UE to the communication data for each remote UE. For example, this identification information may be included in the SL's MAC CE. It is preferable to transmit the SL's MAC CE, which includes this identification information, along with the communication data for each remote UE. Alternatively, the identification information may be included in the SL control information transmitted along with the communication data. For example, the identification information may be included in the SCI. The identification information may also be included in the SCI and transmitted via PSSCH. In this way, the remote UE can recognize which remote UE the communication data received from the relay UE is destined for. This method may also be applied when there is only one remote UE. The same effect can be obtained in this case as well.

[0462] Alternatively, the relay UE may include information identifying the destination remote UE with the SL control information sent to each remote UE. For example, this identification information may be included in the SCI. Or, it may be included in the SCI and transmitted via PSCCH. In this way, the remote UE can recognize which remote UE the communication data received from the relay UE is destined for. This method may also be applied when there is only one remote UE. The same effect can be obtained in this case as well.

[0463] Multiple remote UEs that perform one DL scheduling and / or one SL scheduling may be grouped together. Such groups may be established. The method described above may be applied to group casting to remote UEs. The method may also be applied to group casting from one relay UE to multiple remote UEs within a group.

[0464] For communication between a remote UE and a gNB via a relay UE, the scheduling of communication from the remote UE to the gNB should also be appropriately applied to the scheduling method for communication from the gNB to the remote UE disclosed above. The DL scheduling should be changed to UL scheduling. The SL scheduling should be changed to SL scheduling from the remote UE to the relay UE. The transmission methods for SL scheduling information, UL scheduling information, communication data, etc., should be appropriately applied to the methods disclosed above. By doing so, similar effects can be obtained.

[0465] By using the method disclosed in Modification 3 of this Embodiment 3, scheduling becomes possible when communication between multiple remote UEs and gNBs takes place via a single relay UE. Furthermore, by sharing SL scheduling, DL scheduling, and UL scheduling for communication between each remote UE and gNB, the amount of signaling required for scheduling can be reduced, and the efficiency of wireless resource utilization can be improved.

[0466] Modification 4 of Embodiment 3. Modification 4 of this embodiment 3 discloses a method for transmitting an SR (scheduling request) in communication between a remote UE and a gNB via a relay UE.

[0467] This transmission method includes a SR (which may hereafter be referred to as a relay SR) for communication between the remote UE and the gNB via a relay UE. A relay SR may also be provided to be transmitted from the remote UE to the gNB via the relay UE. The relay SR may consist of scheduling requests for both SL scheduling and UL scheduling. Upon receiving the relay SR, the gNB performs SL scheduling and UL scheduling for communication from the remote UE to the gNB via the relay UE.

[0468] Methods for transmitting relay SRs are disclosed. A remote UE may transmit a relay SR via RRC signaling. A relay SR may be transmitted in an RRC message. The RRC signaling may include information to identify which remote UE the SR is from. For example, the remote UE identifier may be included in the RRC signaling. The RRC signaling may also include information to identify which relay UE the remote UE is transmitting the SR through. For example, the relay UE identifier may be included.

[0469] When a remote UE generates communication data for the gNB, it sends a relay SR to the gNB via the relay UE using RRC signaling. Upon receiving the relay SR from the remote UE, the gNB performs SL scheduling and UL scheduling for the remote UE and the relay UE connected to the remote UE. The gNB then sends SL scheduling information and UL scheduling information to the remote UE and the relay UE.

[0470] Other methods are disclosed for transmitting a relay SR from a remote UE to a gNB via a relay UE. For example, the relay SR may be transmitted from the remote UE to the relay UE using the SL's RRC signaling. The relay SR may also be transmitted from the relay UE to the gNB using the RRC signaling. Alternatively, the relay SR may be transmitted using MAC signaling. The relay SR may also be transmitted in the MAC CE. The relay SR may be transmitted from the remote UE to the relay UE using the SL's MAC signaling. The relay SR may also be transmitted from the relay UE to the gNB using MAC signaling. This allows for early transmission with a low error rate.

[0471] Alternatively, the remote UE may transmit the relay SR via L1 / L2 signaling, for example. The remote UE may transmit the relay SR to the relay UE via the SL's L1 / L2 signaling. This allows for earlier transmission of the relay SR. The remote UE may transmit the relay SR by including it in the SL's SCI. The remote UE may transmit the relay SR by including it in the PSCCH. The remote UE may transmit the relay SR on the SL together with the communication data. The remote UE may transmit the relay SR by including it in the PSSCH. By transmitting the relay SR together with the communication data on the SL, the next scheduling can be performed earlier. The relay UE may notify the gNB of the relay SR via L1 / L2 signaling. In this case, the relay SR can be transmitted earlier. The relay SR may be transmitted by including it in the UCI. The relay SR may be transmitted by including it in the PUCCH. The relay SR may be transmitted on the UL together with the communication data. You may include the relay SR in the PUSCH message when sending communication data on the UL. Sending the relay SR along with the communication data allows for earlier scheduling of the next step.

[0472] The methods disclosed above may be combined as appropriate. The method for transmitting relay SRs in SL and the method for transmitting relay SRs in UL may be combined as appropriate.

[0473] The gNB schedules the transmission of relay SRs to the remote UE. In scheduling the transmission of relay SRs, the gNB may set the transmission timing of the relay SRs to be periodic. The gNB may also configure the relay SR transmission resources on the SL and on the UL for the remote UE. For example, the gNB may configure PSCCH for relay SR transmission on the SL, and PUCCH for relay SR transmission on the UL. The gNB transmits these settings to the relay UE and the remote UE. These settings may also be transmitted via RRC signaling. Transmitting via RRC signaling allows for the transmission of a large amount of information.

[0474] In this way, the remote UE can send a relay SR to the gNB via the relay UE. When communication data to the gNB is generated at the remote UE, the gNB can schedule the communication. Communication from the remote UE to the gNB via the relay UE becomes possible.

[0475] This document discloses a method for transmitting other service signals (SRs) in communication between a remote UE and a gNB via a relay UE. In this transmission method, separate SRs are provided for SL communication and UL communication in the communication. The remote UE transmits the SL SR and the UL SR separately to the gNB. When the gNB receives the SL SR from the remote UE, it performs SL scheduling for communication from the remote UE to the gNB via the relay UE. When the gNB receives the UL SR from the remote UE, it performs UL scheduling for communication from the remote UE to the gNB via the relay UE.

[0476] By sending separate SRs for SL and UL, scheduling for SL and UL can be performed independently. For example, if scheduling for one of them is required, scheduling for the other does not need to be performed. For example, the transmission method of this SR may be used for retransmission requests. For example, if only UL communication data cannot be sent or received, the remote UE will resend only the UL SR to the gNB. By eliminating the need to send an SL SR, processing can be simplified. In addition, the amount of signaling and wireless resources can be reduced.

[0477] The method for transmitting SRs for SL and SRs for UL may be appropriately applied using the method disclosed above. The same effects as the method disclosed above can be obtained. The gNB sets the transmission timing for SL SRs and UL SRs for the remote UE. The transmission timing for SL SRs may be periodic. The transmission timing for UL SRs may also be periodic. The gNB may set the resources for transmitting SL SRs and UL SRs for the remote UE. For example, PSCCH may be set for SL SR transmission. PUCCH may be set for UL SR transmission. The gNB transmits these settings to the relay UE and the remote UE. These settings may also be transmitted via RRC signaling. When transmitted via RRC signaling, a large amount of information can be transmitted.

[0478] In the preceding section, it was disclosed that the remote UE transmits SRs for SL and SRs for UL separately to the gNB. However, as an alternative, the remote UE may transmit an SR for SL to the gNB, and the relay UE may transmit an SR for UL to the gNB. The relay UE transmits an SR for UL to the gNB in ​​response to receiving communication data from the remote UE. When the gNB receives an SR for SL from the remote UE, it performs SL scheduling, and when it receives an SR for UL from the relay UE, it performs UL scheduling.

[0479] The gNB sets the transmission timing for the SL SR to the remote UE and the transmission timing for the UL SR to the relay UE. The transmission timing for the SL SR may be periodic. The transmission timing for the UL SR may also be periodic. The gNB may set the resources for transmitting the SL SR to the remote UE and the resources for transmitting the UL SR to the relay UE. These settings may also be transmitted via RRC signaling. When transmitted via RRC signaling, a large amount of information can be transmitted.

[0480] By using the method disclosed in Modification 4 of Embodiment 3, even in communication between a remote UE and a gNB via a relay UE, when communication data to the gNB is generated at the remote UE, the gNB can schedule the communication. Therefore, communication from the remote UE to the gNB via the relay UE becomes possible.

[0481] The relay UE may notify the gNB of the relay communication processing time. This may be notified as a capability of the relay UE. The gNB may use the relay communication processing time received from the relay UE to perform scheduling for SL and / or DL ​​and / or UL for relay communication. For example, the gNB may perform the scheduling for relay communication by setting a time difference between the transmission timing on SL and the transmission timing on UL. The gNB may use the relay communication processing time received from the relay UE to perform scheduling for DL, SL, and UL. The gNB may perform scheduling for DL, SL, and UL by setting a time difference between the transmission timing on SL and the transmission timing on DL or UL.

[0482] The relay communication processing time may be one or multiple. A relay UE may relay communication between multiple remote UEs and the gNB. For example, in such cases, the gNB may be notified of a single relay communication processing time. This simplifies scheduling on the gNB.

[0483] Alternatively, for example, multiple relay communication processing times may be set up with different times for communication between each remote UE and the gNB. The relay UE should notify the gNB of the relay communication processing time corresponding to the communication between each remote UE and the gNB. The notification to the gNB may include the relay communication processing time, information to identify each remote UE, and / or information to identify the communication between each remote UE and the gNB. In this way, when the processing time at the relay UE differs depending on the service of each communication, flexible scheduling for DL, SL, and UL can be implemented, taking into account the optimal relay communication processing time.

[0484] Modification 5 of Embodiment 3. When a relay UE handles communication between multiple remote UEs and gNBs, a problem can arise where communication between one remote UE and gNB is delayed by communication between other remote UEs and gNBs.

[0485] Modification 5 of this embodiment 3 discloses a method for solving these problems.

[0486] Modification 5 of this embodiment 3 discloses a method for solving the above-mentioned problems in communication from a gNB to a remote UE via a relay UE. The relay UE performs priority processing from the relay UE to the remote UE. That is, the relay UE prioritizes communication between the remote UE and the gNB, which has a higher priority, and transmits communication data to the remote UE. Preemption may be performed when transmitting from the relay UE to the remote UE.

[0487] If the relay UE and the remote UE are scheduled individually for each remote UE, the relay UE may send high-priority data from the gNB using the earliest scheduled resource. Preemption at the service level (SL) may be applied. When applying preemption at the SL, the occurrence of SL data in the preemption should be replaced with data reception from the gNB.

[0488] This document discloses a solution to the above-mentioned problems in communication from a remote UE to a gNB via a relay UE. The relay UE performs priority processing for communication from the relay UE to the gNB. That is, the relay UE prioritizes communication between the remote UE and the gNB, which has a higher priority, and transmits communication data to the gNB. Preemption may be performed when transmitting from the relay UE to the gNB.

[0489] If the relay UE and gNB are scheduled individually for each remote UE, the relay UE may send high-priority data from the remote UEs using the earliest scheduled resource. Preemption at UL may be applied. When applying preemption at UL, the generation of UL data in the preemption should be replaced with the reception of data from the remote UE.

[0490] This approach allows for communication between the remote UE and gNB via the relay UE to be conducted in a manner that is appropriate to the priority of the communication. For example, communication between the remote UE and gNB for communication services requiring low latency can be performed before communication between other remote UEs and gNBs with lower priority.

[0491] Modification 6 of Embodiment 3. In communication between a remote UE and a gNB via a relay UE, the remote UE connects to the gNB through the relay UE. Therefore, the question arises as to how to notify the remote UE of the gNB's System Information (SI). 3GPP has discussed supporting SI notification in communication between remote UEs and gNBs via a relay UE (see Non-Patent Document 27 (3GPP TR38.836)). However, no specific method for notifying the remote UE of the SI has been discussed.

[0492] Modification 6 of this embodiment 3 discloses a method for solving these problems.

[0493] Modification 6 of this embodiment 3 discloses a method for solving the above-mentioned problems in communication between a remote UE and a gNB via a relay UE. A logical channel of PC5 used to transmit the gNB's SI is disclosed. The gNB's SI is mapped to the SL's SBCCH. The gNB's SI may be an MIB and / or SIB. The gNB's SI notified to the remote UE may be the same as the SI that the gNB broadcasts to UEs in coverage, a part of that SI, or different from that SI. A combination of these may also be used. For example, the gNB's SI notified to the remote UE may be the SI that the gNB broadcasts to UEs in coverage, which is necessary for communication between the remote UE and the gNB via the relay UE.

[0494] Traditionally, side-link system information is mapped to SBCCH. Alternatively, the gNB's SI can be mapped to SBCCH along with the side-link system information. This allows the same logical channel to be used, avoiding increased processing complexity.

[0495] Alternatively, a separate SBCCH for gNB SI may be provided, distinct from the SBCCH used to map sidelink system information. Providing different SBCCHs makes it easier to differentiate information in relay UEs and remote UEs, thereby reducing malfunctions.

[0496] The transport channel of PC5 used to transmit the gNB's SI is disclosed. The gNB's SI is mapped to SL-BCH. The gNB's SI is mapped to the logical channel SBCCH, which is mapped to the transport channel SL-BCH. A relay UE that receives the SI from the gNB maps the SI to SBCCH, and then maps SBCCH to SL-BCH and transmits it to the remote UE.

[0497] In this way, the relay UE can send the gNB's SI to one or more remote UEs.

[0498] Another method for the transport channel of PC5 used to transmit the gNB's SI is disclosed. The gNB's SI is mapped to SL-SCH. The gNB's SI is mapped to the logical channel SBCCH, which is mapped to the transport channel SL-SCH. A relay UE that receives the SI from the gNB maps the SI to SBCCH, and then maps SBCCH to SL-SCH and transmits it to the remote UE.

[0499] SBCCHs with sidelink system information mapped to them may be mapped to SL-BCHs, and SBCCHs with SI information from gNBs mapped to them may be mapped to SL-SCHs. This makes it easier to separate the information in relay UEs and remote UEs, thereby reducing malfunctions.

[0500] The SL-SCH with the gNB's SI mapped may be transmitted by unicast. This allows the gNB's SI to be transmitted to individual remote UEs. The SL-SCH with the gNB's SI mapped may be transmitted by groupcast. This allows the gNB's SI to be transmitted to UEs belonging to a predetermined group. The SL-SCH with the gNB's SI mapped may be transmitted by broadcast. This allows the gNB's SI to be transmitted to one or more remote UEs.

[0501] The frequency-time resources available for transmitting PSBCHs to which SL-BCHs are mapped are limited (see Non-Patent Document 16 (3GPP TS38.300)). PSBCHs are configured with sidelink synchronization signals within one slot and are mapped to only nine symbols within that slot. As a result, PSBCHs can transmit only a small amount of information, which may be insufficient for transmitting gNB SIs. Furthermore, because PSBCHs are transmitted with SL synchronization signals, their transmission timing may be limited.

[0502] By mapping the SBCCH, which maps the SI from the gNB, to the SL-SCH, the amount of information that can be transmitted can be increased. Furthermore, since there is no need to wait for a limited timing, the gNB's SI can be transmitted earlier, improving low-latency characteristics.

[0503] An alternative method for the logical channel of PC5 used to transmit the gNB's SI is disclosed. The gNB's SI is mapped to the SL's STCH. The transport channel of PC5 is disclosed. The gNB's SI is mapped to the SL-SCH. The gNB's SI is mapped to the logical channel STCH, which is mapped to the transport channel SL-SCH. A relay UE that receives the SI from the gNB maps the SI to the STCH, maps the STCH to the SL-SCH, and transmits it to the remote UE.

[0504] The SL-SCH with the gNB's SI mapped may be transmitted via unicast, groupcast, or broadcast. Each method will produce the same effect as described above.

[0505] In this way, the mapping of the gNB's SI from STCH to SL-SCH can be processed in the same way as information mapped to other STCHs. This avoids complicating the gNB's SI transmission and reception processing at relay UEs and remote UEs. Furthermore, as disclosed above, mapping the gNB's SI to SL-SCH increases the amount of information that can be transmitted, enables earlier transmission of the gNB's SI, and improves low-latency characteristics.

[0506] The methods disclosed above may be combined as appropriate. For example, the logical channel or transport channel transmitted on the SL may be changed depending on the content of the gNB's SI. For example, if the gNB's SI contains MIB information, the relay UE maps the gNB's MIB information to SBCCH and then to SL-BCH. If the gNB's SI contains SIB information, the relay UE maps the gNB's SIB information to STCH and then to SL-SCH. This is effective when the amount of MIB information of the gNB to be transmitted to the remote UE is small.

[0507] For example, if the gNB's SI contains information common to all UEs, the relay UE maps that information to SBCCH and then to SL-BCH. If the gNB's SI contains information specific to a particular UE, the relay UE maps that information to STCH and then to SL-SCH. SL-SCH is capable of unicast communication. Therefore, this is effective when the gNB's SI sent to a remote UE contains information specific to that UE.

[0508] A remote UE may request the gNB to send its SI. In response to this request, the gNB may send its SI to the remote UE via the relay UE. In such a case of sending the gNB's SI in response to a request from the remote UE, the relay UE also sends the gNB's SI over the SL to the remote UE, and the channel mapping method described above may be applied as appropriate. For example, in the case of the gNB's SI in response to a request from the remote UE, the relay UE maps the information to the STCH and then to the SL-SCH. The relay UE can then send the gNB's SI to the remote UE that requested the gNB's SI using unicast transmission.

[0509] When transmitting a gNB SI on the SL, the SCI may include information indicating that it is a gNB SI. For example, if a relay UE maps a gNB SI to an SBCCH and then maps that SBCCH to an SL-SCH for transmission, it is advisable to include information indicating that it is a gNB SI in the SCI for that transmission. This allows the remote UE to determine that it is a gNB SI. The remote UE can then recognize that a gNB SI is mapped to the SL-SCH received from the relay UE and can receive the gNB SI.

[0510] For example, if a relay UE maps the gNB's SI to an STCH and then maps the STCH to an SL-SCH for transmission, it may include information in the SCI for transmission indicating that it is the gNB's SI. As in the case described above, the remote UE can recognize that the SL-SCH received from the relay UE is mapped to the gNB's SI. The remote UE can then receive the gNB's SI.

[0511] Other methods are disclosed that enable a remote UE to determine that a gNB SI is present. The MAC header or MAC CE may include information indicating that it is a gNB SI. For example, when a relay UE maps a gNB SI to an SBCCH and then maps the SBCCH to an SL-SCH for transmission, the MAC layer includes information indicating that it is a gNB SI in the MAC header or MAC CE before mapping to the SL-SCH. In this way, the remote UE can determine that it is a gNB SI. The remote UE can recognize whether the SL-SCH received from the relay UE is a gNB SI or not. The remote UE can receive gNB SIs.

[0512] For example, when a relay UE maps the gNB's SI to an STCH and then maps the STCH to an SL-SCH for transmission, it may include information indicating that it is the gNB's SI in the MAC header or MAC CE at the MAC layer before mapping to the SL-SCH. As in the case described above, the remote UE can recognize whether the SL-SCH received from the relay UE is the gNB's SI or not. The remote UE can then receive the gNB's SI.

[0513] The state of the remote UE receiving the gNB's SI may be RRC connected to the gNB, RRC inactive, or RRC idle. The methods disclosed above may be applied as appropriate. If the remote UE is RRC connected to the gNB, the gNB's SI may be included in an RRC message and sent from the gNB to the remote UE via the relay UE. The RRC message containing the gNB's SI may be containerized in the RRC signaling of Uu and the RRC signaling of PC5 and sent. In such cases as well, the methods disclosed above may be applied as appropriate for the relay UE to send the gNB's SI to the remote UE via SL. For example, the relay UE maps the gNB's SI to STCH, maps the STCH to SL-SCH, and sends it. In this way, the remote UE can receive the gNB's SI.

[0514] By using the method disclosed in Modification 6 of this Embodiment 3, in communication between a remote UE and a gNB via a relay UE, the relay UE can transmit the gNB's SI received from the gNB to the remote UE. The remote UE can obtain the gNB's SI necessary for communicating with the gNB via the relay UE. Communication between the remote UE and the gNB via the relay UE becomes possible.

[0515] In this disclosure, the terms gNB and cell are used, but unless otherwise specified, they may refer to either gNB or cell.

[0516] The embodiments and their variations described above are merely illustrative, and these embodiments and their variations can be freely combined. Furthermore, any component of each embodiment and its variations can be modified or omitted as appropriate.

[0517] For example, in the embodiments and their modifications described above, a subframe is an example of a time unit for communication in a fifth-generation communication system. A subframe may also be a scheduling unit. In the embodiments and their modifications described above, the processing described as being performed in subframe units may also be performed in TTI units, slot units, sub-slot units, or mini-slot units.

[0518] For example, the methods disclosed in each of the embodiments and their variations described above may be applied not only to V2X (Vehicle-to-everything) services but also to services that use SL communication. For example, they may be applied to SL communication used in various services such as proximity-based services, public safety, communication between wearable devices, and communication between machines in factories.

[0519] Although this disclosure has been described in detail, the above description is illustrative and not limiting in all respects. It is understood that countless variations not illustrated are conceivable. [Explanation of Symbols]

[0520] 200,210 Communication system, 202 Communication terminal equipment (mobile terminal), 203,207,213,217,223-1,224-1,224-2,226-1,226-2,750 Base station equipment (base station), 204 MME / S-GW section (MME section), 204a MME, 214 AMF / SMF / UPF section (5GC section), 218 Central unit, 219 Distributed unit, 301,403 Protocol processing section, 302 Application section, 303,404 Transmit data buffer section, 304,405 Encoder section, 305,406 Modulation section, 306,407 Frequency conversion section, 307-1~307-4,408-1~408-4 Antenna, 308,409 Demodulation section, 309,410 Decoder section, 310, 411, 506, 526 Control section, 401 EPC communication section, 402 Other base station communication section, 412 5GC communication section, 501 PDN GW communication section, 502, 522 Base station communication section, 503, 523 User plane communication section, 504 HeNBGW communication section, 505, 525 Control plane control section, 505-1, 525-1 NAS security section, 505-2 SAE bearer control section, 505-3, 525-3 Idle state mobility management section, 521 Data Network communication section, 525-2 PDU session control section, 527 Session management section, 751-1~751-8 Beam.

Claims

1. A remote UE that communicates with base station equipment and relay UE, A request to transmit system information is sent to the base station device via the relay UE. Remote UE.

2. The system information is received from the base station device via the relay UE. The remote UE according to claim 1.

3. The system information is received when the RRC connection is active. The remote UE according to claim 2.

4. The aforementioned system information is included in the RRC message. The remote UE according to claim 2.

5. The aforementioned system information is mapped to SL-SCH. The remote UE according to claim 2.

6. A base station device that communicates with relay UEs and remote UEs, The relay UE receives a request to transmit system information from the remote UE. Base station equipment.

7. A communication system including a base station device, a relay UE, and a remote UE, The remote UE transmits a request to the base station device to transmit system information via the relay UE. Communication system.

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