User device, base station and communication system

Abstract

To provide a radio communication technique which can achieve low delay property, high reliability and low jitter characteristics.SOLUTION: A transmission side device is configured to copy a packet and transmit the copied packet. A reception side device is configured to receive the copied packet. The reception side device is configured to transfer first packets (1401, 1403, 1405, 1408) which are packets received earlier among the copied packets to a high-order layer in the reception side device. A transfer timing which is a timing for transferring the first packets (1401, 1403, 1405, 1408) to the high-order layer includes at least one of a reception timing of second packets (1402, 1404, 1406, 1407) which are packets received after the first packets among the copied packets, and a periodic timing (cycle time) corresponding to a transmission period of the copied packet.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] The present invention relates to wireless communication technology. [Background technology]

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

[0003] LTE uses OFDM (Orthogonal Frequency Division Multiplexing) for downlink and SC-FDMA (Single Carrier Frequency Division Multiple Access) for uplink as its access method. 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 configuration in the LTE system, which are described in Non-Patent Document 1 (Chapter 5), will be explained with reference to FIG. 1. FIG. 1 is an explanatory diagram showing the configuration of a radio frame used in an LTE communication system. In FIG. 1, one radio frame is 10 ms. The radio frame is divided into 10 subframes of equal size. The subframe is divided into two slots of equal size. The first and sixth subframes of each radio frame include a downlink synchronization signal. The synchronization signal includes a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS).

[0005] The decisions made by 3GPP regarding the channel configuration in the LTE system are described in Non-Patent Document 1 (Chapter 5). It is assumed that the same channel configuration as that of a non-CSG cell is used in a CSG (Closed Subscriber Group) cell.

[0006] The Physical Broadcast Channel (PBCH) is a channel for downlink transmission from a base station device (hereinafter, sometimes simply referred to as a "base station") to a communication terminal device (hereinafter, sometimes simply referred to as a "communication terminal") such as a mobile terminal device (hereinafter, sometimes simply referred to as a "mobile terminal"). A BCH transport block is mapped to four subframes in a 40 ms interval. There is no explicit signaling of the 40 ms timing.

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

[0008] The Physical Downlink Control Channel (PDCCH) is a channel for downlink transmission from a base station to a communication terminal. The PDCCH reports resource allocation information for a Downlink Shared Channel (DL-SCH), which is one of the transport channels described below, resource allocation information for a Paging Channel (PCH), which is one of the transport channels described below, and Hybrid Automatic Repeat reQuest (HARQ) information for the DL-SCH. The PDCCH carries an uplink scheduling grant. The PDCCH carries Acknowledgement (Acknowledgement) / Nack (Negative Acknowledgement), which are response signals to uplink transmission. The PDCCH is also called an L1 / L2 control signal.

[0009] A physical downlink shared channel (PDSCH) is a channel for downlink transmission from a base station to a communication terminal. A downlink shared channel (DL-SCH), which is a transport channel, and a PCH, which is a transport channel, are mapped to the PDSCH.

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

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

[0012] A Physical Uplink Shared Channel (PUSCH) is a channel for uplink transmission from a communication terminal to a base station. An 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 a channel for downlink transmission from a base station to a communication terminal. The PHICH carries Ack / Nack, which is a response signal to an uplink transmission. The Physical Random Access Channel (PRACH) is a channel for uplink transmission from a communication terminal to a base station. The PRACH carries a random access preamble.

[0014] Downlink reference signals (RS) are known symbols in LTE communication systems. The following five types of downlink reference signals are defined: Cell-specific Reference Signal (CRS), MBSFN Reference Signal, UE-specific Reference Signal (DM-RS) Demodulation Reference Signal (PRS), Positioning Reference Signal (PRS), and Channel State Information Reference Signal (CSI-RS). Measurement of the physical layer of a communication terminal includes measurement of the reference signal received power (RSRP).

[0015] Similarly, the uplink reference signal is a known symbol in the LTE communication system. Two types of uplink reference signals are defined: a data demodulation reference signal (DM-RS) and a sounding reference signal (SRS).

[0016] The transport channel described in Non-Patent Document 1 (Chapter 5) will be explained. Among the downlink transport channels, the broadcast channel (BCH) is broadcast to the entire coverage of the base station (cell). The BCH is mapped to the physical broadcast channel (PBCH).

[0017] Retransmission control using HARQ (Hybrid ARQ) is applied to the Downlink Shared Channel (DL-SCH). DL-SCH can be 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) of communication terminals to reduce power consumption of communication terminals. DL-SCH is mapped to the physical downlink shared channel (PDSCH).

[0018] The Paging Channel (PCH) supports DRX of communication terminals to enable low power consumption of the communication terminals. The PCH is required to be broadcast to the entire coverage of the base station (cell). The PCH is mapped to physical resources such as the Physical Downlink Shared Channel (PDSCH) that can be dynamically used for traffic.

[0019] The Multicast Channel (MCH) is used for broadcasting to the entire coverage of a base station (cell). The MCH supports SFN combining of MBMS (Multimedia Broadcast Multicast Service) services (MTCH and MCCH) in multi-cell transmission. The MCH supports semi-static resource allocation. The MCH is mapped to the PMCH.

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

[0021] The Random Access Channel (RACH) is limited to control information. The RACH is subject to collision risk. The RACH is mapped to the Physical Random Access Channel (PRACH).

[0022] Let us explain about HARQ. HARQ is a technology that improves the communication quality of a transmission line by combining Automatic Repeat reQuest (ARQ) and Forward Error Correction. HARQ has the advantage that error correction works effectively by retransmission even for transmission lines whose communication quality changes. In particular, it is possible to obtain further quality improvement by combining the reception result of the initial transmission and the reception result of the retransmission when retransmitting.

[0023] An example of a retransmission method will be described below. If the received data cannot be decoded correctly on the receiving side, in other words, if a CRC (Cyclic Redundancy Check) error occurs (CRC=NG), the receiving side will send a "Nack" to the transmitting side. The transmitting side that receives the "Nack" will retransmit the data. If the received data can be decoded correctly on the receiving side, in other words, if no CRC error occurs (CRC=OK), the receiving side will send an "Ack" to the transmitting side. The transmitting side that receives the "Ack" will send the next data.

[0024] The logical channel described in Non-Patent Document 1 (Chapter 6) will be explained. The Broadcast Control Channel (BCCH) is a downlink channel for broadcast system control information. The logical channel BCCH is mapped to the broadcast channel (BCH) or the downlink shared channel (DL-SCH), which are transport channels.

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

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

[0027] The Multicast Control Channel (MCCH) is a downlink channel for point-to-multipoint transmission. The MCCH is used for transmission of MBMS control information for one or several MTCHs from the network to communication terminals. The MCCH is used only by communication terminals receiving MBMS. The MCCH is mapped to the Multicast Channel (MCH), which is a transport channel.

[0028] A 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. DCCH is used when a communication terminal is in an RRC connection. DCCH is mapped to an uplink shared channel (UL-SCH) in the uplink and to a downlink shared channel (DL-SCH) in the downlink.

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

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

[0031] CGI stands for Cell Global Identifier. ECGI stands for E-UTRAN Cell Global Identifier. CSG (Closed Subscriber Group) cells are introduced in LTE, LTE-A (Long Term Evolution Advanced) (described below), and UMTS (Universal Mobile Telecommunication System).

[0032] The location of a communication terminal is tracked in units of an area consisting of one or more cells. Location tracking is performed to track the location of the communication terminal even when it is in standby mode and to enable the communication terminal to be called, in other words, to allow the communication terminal to receive calls. The area for tracking the location of this communication terminal is called a tracking area.

[0033] 3GPP is also working on the development of standards for Long Term Evolution Advanced (LTE-A) as Release 10 (see Non-Patent Documents 3 and 4). LTE-A is based on the LTE wireless communication method, and is configured by adding several new technologies to it.

[0034] In the LTE-A system, in order to support wider frequency bandwidths (transmission bandwidths) up to 100 MHz, Carrier Aggregation (CA) is being considered, which aggregates two or more Component Carriers (CCs) (also called "aggregation"). CA is described in Non-Patent Document 1.

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

[0036] Depending on the UE's capabilities, a secondary cell (SCell) is configured to form a set of serving cells together with the PCell. In the downlink, the carrier corresponding to the SCell is the downlink secondary component carrier (DL SCC). In the uplink, the carrier corresponding to the SCell is the uplink secondary component carrier (UL SCC).

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

[0038] New technologies for LTE-A include a technology that supports wider bandwidth (Wider Bandwidth Extension) and a Coordinated Multiple Point transmission and reception (CoMP) technology. CoMP, which is being considered for LTE-A by 3GPP, is described in Non-Patent Document 1.

[0039] In addition, in 3GPP, in order to handle the huge traffic in the future, the use of small eNBs (hereinafter sometimes referred to as "small-scale base station devices") that configure small cells is being considered. For example, technologies are being considered that improve frequency utilization efficiency and increase communication capacity by installing many small eNBs and configuring many small cells. Specifically, there is dual connectivity (abbreviated as DC) in which a UE connects to two eNBs to communicate. DC is described in Non-Patent Document 1.

[0040] Of the eNBs performing dual connectivity (DC), one may be referred to as a "master eNB (abbreviated as MeNB)" and the other as a "secondary eNB (abbreviated as SeNB)."

[0041] Mobile network traffic is on the rise, and communication speeds are also getting faster. Once LTE and LTE-A are fully operational, communication speeds are expected to become even faster.

[0042] Furthermore, to cope with the increasing sophistication of mobile communications, fifth-generation (hereinafter sometimes referred to as "5G") wireless access systems are being considered, with the goal of starting services after 2020. For example, in Europe, an organization called METIS has compiled requirements for 5G (see Non-Patent Document 5).

[0043] Compared to the LTE system, the 5G wireless access system requires a system capacity that is 1,000 times greater, a data transmission speed that is 100 times greater, data processing delay that is one-tenth (1 / 10), and 100 times the number of simultaneous connections of communication terminals, while also achieving further reductions in power consumption and reductions in equipment costs.

[0044] In order to meet such demands, 3GPP is currently working on 5G standards as Release 15 (see Non-Patent Documents 6 to 18). The technology for 5G wireless sections 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 to the LTE system and LTE-A system:

[0046] The NR access method uses OFDM for the downlink and OFDM and DFT-s-OFDM (DFT-spread-OFDM) for the uplink.

[0047] NR allows the use of higher frequencies than LTE in order to improve transmission speeds and reduce processing delays.

[0048] In NR, 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 the NR frame configuration, various subcarrier intervals, i.e., various numerologies, are supported. In NR, regardless of the numerology, one subframe is 1 millisecond, and one slot is composed of 14 symbols. In addition, the number of slots included in one subframe is one in a numerology with a subcarrier interval of 15 kHz, and increases in proportion to the subcarrier interval in other numerologies (see Non-Patent Document 13 (TS38.211 v15.0.0)).

[0050] In NR, downlink synchronization signals are transmitted from base stations as synchronization signal bursts (hereinafter sometimes referred to as SS bursts) at a predetermined cycle with a predetermined duration. An SS burst is composed of synchronization signal blocks (hereinafter sometimes referred to as SS blocks) for each beam of the base station. The base station transmits the SS blocks of each beam within the duration of the SS burst by changing the beam. An SS block is composed of P-SS, S-SS, and PBCH.

[0051] In NR, the influence of phase noise is reduced by adding a Phase Tracking Reference Signal (PTRS) as a downlink reference signal for NR. PTRS is also added to the uplink reference signal in the same way as in the downlink.

[0052] In NR, in order to flexibly switch between DL and UL within a slot, slot format indication (SFI) has been added to the information contained in the PDCCH.

[0053] In addition, in NR, a base station pre-configures a portion of the carrier frequency band (hereinafter sometimes referred to as a Bandwidth Part (BWP)) for a UE, and the UE transmits and receives data to and from the base station using that BWP, thereby reducing power consumption in the UE.

[0054] In 3GPP, the following DC forms are being considered: DC by LTE base stations and NR base stations connected to the EPC, DC by NR base stations connected to the 5G core system, and DC by LTE base stations and NR base stations connected to the 5G core system (see non-patent documents 12, 16, and 19).

[0055] Also, 3GPP is considering several new technologies, such as improving jitter characteristics (see Non-Patent Document 20 (3GPP RP-180974)), high-speed cell startup (see Non-Patent Document 21 (3GPP RP-181469)), and unicast communication in sidelink (see Non-Patent Document 22 (3GPP RP-182111)). [Prior art documents] [Non-patent literature]

[0056] [Non-Patent Document 1] 3GPP TS 36.300 V15.2.0 [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 V15.0.0 [Non-Patent Document 5] "Scenarios, requirements and KPIs for 5G mobile and wireless system", ICT-317669-METIS / D1.1

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Non-licensed literature 9

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Non-licensed Document 22

[0057] In 3GPP, in addition to the requirements of low latency and highly reliable communication (Ultra Reliability, Low Latency Communication; URLLC), low jitter characteristics are also required (see Non-Patent Document 20 (3GPP RP-180974) and Non-Patent Document 23 (3GPP TR22.804 V16.1.0)). In order to satisfy the requirements of URLLC, packet duplication is used (see Non-Patent Document 16). However, in packet duplication, the timing of transferring a received packet to a higher layer is not specified. As a result, the timing of transferring a packet to a higher layer by a receiving device differs depending on the decoding result (e.g., CRC result) of the packet that is received first. As a result, latency variation (hereinafter sometimes referred to as jitter) occurs, causing problems such as deterioration of jitter characteristics.

[0058] Also, application of unicast communication is being considered in Side Link (SL) supported for V2V (Vehicle to Vehicle) communication. However, although communication from one UE to another UE is possible, a method for setting transmission resources in communication in the opposite direction, that is, communication from the other UE to the one UE, is not disclosed. Therefore, communication in the opposite direction becomes impossible, and as a result, a problem occurs in that bidirectional communication in unicast communication cannot be established.

[0059] In view of the above problems, one object of the present invention is to provide a wireless communication technology that can achieve low latency, high reliability, and low jitter characteristics in at least one of uplink communication, downlink communication, and sidelink communication. [Means for solving the problem]

[0060] According to the present invention, a user equipment in a communication system including a plurality of user equipments capable of communicating with each other in a sidelink and a base station that wirelessly communicates with each of the plurality of user equipments performs unicast transmission in the sidelink, transmits a scheduling request (SR) or a buffer status report (BSR) to the base station, and receives a resource configuration transmitted from the base station based on the SR or the BSR.

[0061] According to the present invention, there is provided a base station in a communication system including a plurality of user equipment devices capable of communicating with each other in a side link, and a base station that wirelessly communicates with each of the plurality of user equipment devices, wherein the user equipment devices perform unicast transmission in the side link, receive a scheduling request (SR) or a buffer status report (BSR) from the user equipment, and transmit resource configuration to the user equipment devices based on the SR or the BSR. Also, according to the present invention, there is provided a communication system comprising a plurality of user equipment devices capable of communicating with each other in a sidelink, and a base station that wirelessly communicates with each of the plurality of user equipment devices, in which one user equipment performs unicast transmission in the sidelink, transmits a scheduling request (SR) or a buffer status report (BSR) to the base station, and receives a resource configuration transmitted from the base station based on the SR or the BSR. Effect of the Invention

[0062] According to the present invention, it is possible to realize low delay, high reliability, and low jitter characteristics.

[0063] The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings. [Brief description of the drawings]

[0064] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a radio frame used in an LTE communication system. [Diagram 2] 1 is a block diagram showing the overall configuration of a communication system 200 based on the LTE standard that is being discussed in 3GPP. [Diagram 3] FIG. 2 is a block diagram showing the overall configuration of a communication system 210 of the NR standard being discussed in 3GPP. [Figure 4] FIG. 1 is a diagram illustrating a DC configuration using eNBs and gNBs connected to an EPC. [Diagram 5] This is a diagram of a DC using gNB connected to an NG core. [Figure 6] This is a diagram showing the configuration of DC using eNBs and gNBs connected to the NG core. [Figure 7] This is a diagram showing the configuration of DC using eNBs and gNBs connected to the NG core. [Figure 8] FIG. 3 is a block diagram showing a configuration of a mobile terminal 202 shown in FIG. [Figure 9] FIG. 3 is a block diagram showing a configuration of a base station 203 shown in FIG. [Figure 10] FIG. 2 is a block diagram showing the configuration of an MME. [Figure 11] A block diagram showing the configuration of 5GC. [Figure 12] 1 is a flowchart showing an overview of operations from cell search to standby performed by a communication terminal (UE) in an LTE communication system. [Figure 13] FIG. 1 is a diagram showing an example of a cell configuration in an NR system. [Figure 14] FIG. 11 is a diagram illustrating an operation of a receiving-side device for transferring a packet to a higher layer at the reception timing of a packet that is transmitted later among the duplicated packets, in the first embodiment. [Figure 15] FIG. 11 illustrates an operation of a receiving device transferring a received packet to a higher layer at a predetermined timing in the first embodiment. [Figure 16] FIG. 11 is a diagram illustrating another example of the operation of the receiving device in the first embodiment, in which the receiving device transfers a packet to a higher layer at the reception timing of a packet that is transmitted later among the duplicated packets. [Figure 17] FIG. 11 is a diagram illustrating another example of the operation of the receiving device forwarding a received packet to a higher layer at a predetermined timing in the first embodiment. [Figure 18] FIG. 11 is a diagram illustrating an operation of transmitting and receiving duplicated packets on the same carrier, according to the first modification of the first embodiment. [Figure 19] FIG. 11 is a diagram illustrating another example of the operation of transmitting and receiving duplicated packets on the same carrier, in accordance with the first modification of the first embodiment. [Figure 20] FIG. 11 is a diagram illustrating another example of the operation of transmitting and receiving duplicated packets on the same carrier, in accordance with the first modification of the first embodiment. [Figure 21] FIG. 11 is a diagram illustrating another example of the operation of transmitting and receiving duplicated packets on the same carrier, in accordance with the first modification of the first embodiment. [Figure 22]FIG. 11 is a diagram showing an operation of a receiving side device performing HARQ feedback and forwarding to a higher layer in the middle of a predetermined number of repetitions in the repetition, in accordance with the second modification of the first embodiment. [Figure 23] FIG. 11 is a diagram illustrating the operation of an LCP in a case where both a jitter-critical logical channel and a logical channel with a latency requirement exist, in accordance with a third modification of the first embodiment. [Figure 24] FIG. 13 is a diagram illustrating how a priority offset is assigned to a jitter-critical logical channel in accordance with the third modification of the first embodiment. [Diagram 25] FIG. 13 is a diagram showing another example of providing a priority offset to a jitter-critical logical channel in accordance with the third modification of the first embodiment. [Figure 26] FIG. 13 is a diagram illustrating how a priority offset is assigned to a logical channel having a latency requirement, in accordance with the third modification of the first embodiment. [Figure 27] FIG. 11 is a conceptual diagram of SL communication (broadcast communication) according to the third embodiment. [Figure 28] FIG. 11 is a conceptual diagram of SL communication (unicast communication) according to the third embodiment. [Figure 29] 13 shows a first example of a sequence up to unicast communication between two UEs for SL unicast, in accordance with the first modification of the third embodiment. [Diagram 30] 13 illustrates a second example of a sequence up to unicast communication between two UEs for SL unicast, according to the first modification of the third embodiment. [Diagram 31] 13 illustrates a third example of a sequence up to unicast communication between two UEs for SL unicast, according to the first modification of the third embodiment. [Diagram 32] 13 illustrates a fourth example of a sequence up to unicast communication between two UEs for SL unicast, according to the first modification of the third embodiment. [Diagram 33] 13 illustrates a fifth example of a sequence up to unicast communication between two UEs for SL unicast, according to the first modification of the third embodiment. [Diagram 34]13 illustrates a sixth example of a sequence up to unicast communication between two UEs for SL unicast, according to the first modification of the third embodiment. [Diagram 35] 13 illustrates a seventh example of a sequence up to unicast communication between two UEs for SL unicast, according to the first modification of the third embodiment. [Diagram 36] FIG. 13 is a conceptual diagram showing an example of a method for reserving resources used for initial transmission and / or retransmission in SL, in accordance with the fifth embodiment. [Figure 37] FIG. 13 is a conceptual diagram showing an example of a method for reserving multiple sets of periodic resources for initial transmission and / or retransmission in SL in accordance with the fifth embodiment. [Figure 38] FIG. 13 is a conceptual diagram showing an example of a method for individually reserving resources used for initial transmission and resources used for retransmission in SL, in accordance with the fifth embodiment. [Figure 39] FIG. 13 is a conceptual diagram showing an example of a method for reserving a group of resources used for initial transmission and retransmission in SL, in accordance with the fifth embodiment. [Diagram 40] FIG. 13 is a conceptual diagram showing an example of a method for reserving resources used for retransmission in SL at the time of retransmission, in accordance with the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] Embodiment 1 Fig. 2 is a block diagram showing the overall configuration of an LTE-based communication system 200 being discussed in 3GPP. Fig. 2 will now be described. The radio access network is called E-UTRAN (Evolved Universal Terrestrial Radio Access Network) 201. A mobile terminal device (hereinafter referred to as "mobile terminal (User Equipment: UE)") 202, which is a communication terminal device, is capable of wireless communication with a base station device (hereinafter referred to as "base station (E-UTRAN NodeB: eNB)") 203, and transmits and receives signals via wireless communication.

[0066] Here, the term "communication terminal device" includes not only mobile terminal devices such as mobile mobile phone terminal devices, but also stationary devices such as sensors. In the following description, the "communication terminal device" may be simply referred to as a "communication terminal."

[0067] If control protocols for mobile terminals 202, such as RRC (Radio Resource Control), and user planes (hereinafter sometimes referred to as U-Planes), such as PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer), terminate in a base station 203, E-UTRAN is composed of one or more base stations 203.

[0068] A control protocol RRC (Radio Resource Control) between the mobile terminal 202 and the base station 203 performs broadcast, paging, RRC connection management, etc. The states of the base station 203 and the mobile terminal 202 in RRC include RRC_IDLE and RRC_CONNECTED.

[0069] In RRC_IDLE, PLMN (Public Land Mobile Network) selection, System Information (SI) broadcast, paging, cell re-selection, mobility, etc. are performed. In RRC_CONNECTED, the mobile terminal has an RRC connection and can transmit and receive data with the network. In addition, in RRC_CONNECTED, handover (HO), measurement of neighbor cells, etc. are performed.

[0070] The base station 203 is composed of one or more eNBs 207. A system composed of the core network EPC (Evolved Packet Core) and the radio access network E-UTRAN 201 is called an EPS (Evolved Packet System). The core network EPC and the radio access network E-UTRAN 201 are sometimes collectively called a "network."

[0071] 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 an "MME unit") 204 including an MME and an S-GW via an S1 interface, and control information is communicated between the eNB207 and the MME unit 204. A plurality of MME units 204 may be connected to one eNB207. The eNBs 207 are connected to each other via an X2 interface, and control information is communicated between the eNBs 207.

[0072] The MME unit 204 is an upper device, specifically an upper node, and controls a connection between the eNB 207, which is a base station, and the mobile terminal (UE) 202. The MME unit 204 constitutes the EPC, which is a core network. The base station 203 constitutes the E-UTRAN 201.

[0073] The base station 203 may configure one cell or multiple cells. Each cell has a predetermined range as a coverage area in which communication with the mobile terminal 202 is possible, and performs wireless communication with the mobile terminal 202 within the coverage area. When one base station 203 configures multiple cells, each cell is configured to be able to communicate with the mobile terminal 202.

[0074] FIG. 3 is a block diagram showing the overall configuration of a 5G communication system 210 being discussed in 3GPP. FIG. 3 will be described. The radio access network is called NG-RAN (Next Generation Radio Access Network) 211. The UE 202 is capable of wireless communication with an NR base station device (hereinafter referred to as "NR base station (NG-RAN NodeB: gNB)") 213, and transmits and receives signals via wireless communication. The core network is called 5G Core (5G Core: 5GC).

[0075] If control protocols for UE202, such as RRC (Radio Resource Control), and 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), terminate at the NR base station 213, the NG-RAN is composed of one or more NR base stations 213.

[0076] The function of the control protocol RRC (Radio Resource Control) between the UE 202 and the NR base station 213 is similar to that of LTE. The states of the NR base station 213 and the UE 202 in the RRC include RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE.

[0077] RRC_IDLE and RRC_CONNECTED are the same as those in the LTE system. In RRC_INACTIVE, the connection between the 5G core and the NR base station 213 is maintained, and system information (SI) is reported, paging, cell re-selection, mobility, and the like are performed.

[0078] The gNB 217 is connected to an AMF / SMF / UPF unit (hereinafter sometimes referred to as a "5GC unit") 214 including an Access and Mobility Management Function (AMF), a Session Management Function (SMF), or a User Plane Function (UPF), or an AMF, SMF, and UPF, via an NG interface. Control information and / or user data are communicated between the gNB 217 and the 5GC unit 214. The NG interface is a collective term for the N2 interface between the gNB 217 and the AMF, the N3 interface between the gNB 217 and the UPF, the N11 interface between the AMF and the SMF, and the N4 interface between the UPF and the SMF. A plurality of 5GC units 214 may be connected to one gNB 217. The gNBs 217 are connected to each other via an Xn interface, and control information and / or user data are communicated between the gNBs 217.

[0079] The NR base station 213 may configure one or more cells, similar to the base station 203. When one NR base station 213 configures multiple cells, each of the cells is configured to be capable of communicating with the UE 202.

[0080] The gNB 217 may be divided into a central unit (hereinafter, sometimes referred to as CU) 218 ​​and a distributed unit (hereinafter, sometimes referred to as DU) 219. One CU 218 is configured in the gNB 217. One or more DUs 219 are configured in the gNB 217. The CU 218 is connected to the DU 219 by an F1 interface, and control information and / or user data are communicated between the CU 218 and the DU 219.

[0081] FIG. 4 is a diagram showing a configuration of DC by eNB and gNB connected to EPC. In FIG. 4, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In FIG. 4, eNB223-1 is a master base station, and gNB224-2 is a secondary base station (this DC configuration may be referred to as EN-DC). In FIG. 4, an example is shown in which U-Plane connection between MME unit 204 and gNB224-2 is made via eNB223-1, but it may also be made directly between MME unit 204 and gNB224-2.

[0082] FIG. 5 is a diagram showing a DC configuration by a gNB connected to an NG core. In FIG. 5, a solid line indicates a U-Plane connection, and a dashed line indicates a C-Plane connection. In FIG. 5, gNB 224-1 is a master base station, and gNB 224-2 is a secondary base station (this DC configuration may be referred to as NR-DC). In FIG. 5, an example is shown in which a U-Plane connection between 5GC unit 214 and gNB 224-2 is made via gNB 224-1, but it may be made directly between 5GC unit 214 and gNB 224-2.

[0083] FIG. 6 is a diagram showing a configuration of DC by eNB and gNB connected to the NG core. In FIG. 6, a solid line indicates a U-Plane connection, and a dashed line indicates a C-Plane connection. In FIG. 6, eNB226-1 becomes a master base station, and gNB224-2 becomes a secondary base station (this DC configuration may be referred to as NG-EN-DC). In FIG. 6, an example is shown in which U-Plane connection between 5GC unit 214 and gNB224-2 is made via eNB226-1, but it may be made directly between 5GC unit 214 and gNB224-2.

[0084] FIG. 7 is a diagram showing another configuration of DC by eNB and gNB connected to the NG core. In FIG. 7, solid lines indicate U-Plane connections, and dashed lines indicate C-Plane connections. In FIG. 7, gNB224-1 is the master base station, and eNB226-2 is the secondary base station (this DC configuration may be referred to as NE-DC). In FIG. 7, an example is shown in which U-Plane connection between 5GC unit 214 and eNB226-2 is made via gNB224-1, but it may be made directly between 5GC unit 214 and eNB226-2.

[0085] FIG. 8 is a block diagram showing the configuration of the mobile terminal 202 shown in FIG. 2. The transmission process of the mobile terminal 202 shown in FIG. 8 will be described. First, the control data from the protocol processing unit 301 and the 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 such as error correction is performed. There may be data that is directly output from the transmission data buffer unit 303 to the modulation unit 305 without encoding. The data that has been encoded by the encoder unit 304 is modulated by the modulation unit 305. Precoding in MIMO may be performed by the modulation unit 305. The modulated data is converted into a baseband signal, and then output to the frequency conversion unit 306, where it is converted into a radio transmission frequency. Thereafter, a transmission signal is transmitted from the antennas 307-1 to 307-4 to the base station 203. Although the case where the number of antennas is four is illustrated in FIG. 8, the number of antennas is not limited to four.

[0086] Moreover, the reception process of the mobile terminal 202 is executed as follows. Radio signals from the base station 203 are received by the antennas 307-1 to 307-4. The received signal is converted from a radio reception frequency to a baseband signal by the frequency conversion unit 306, and demodulated by the demodulation unit 308. The demodulation unit 308 may perform weight calculation and multiplication. The demodulated data is passed to the decoder unit 309, where decoding 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. A series of processes of the mobile terminal 202 is controlled by the control unit 310. Therefore, although the control unit 310 is omitted in FIG. 8, it is connected to each unit 301 to 309. In FIG. 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.

[0087] FIG. 9 is a block diagram showing the configuration of the base station 203 shown in FIG. 2. The transmission process of the base station 203 shown in FIG. 9 will be described. The EPC communication unit 401 transmits and receives data between the base station 203 and the EPC (such as the MME unit 204). The 5GC communication unit 412 transmits and receives data between the base station 203 and the 5GC (such as the 5GC unit 214). The other base station communication unit 402 transmits and receives data between the base station 203 and the 5GC. The EPC communication unit 401, the 5GC communication unit 412, and the other base station communication unit 402 each transmit and receive information to and from the protocol processing unit 403. The control data from the protocol processing unit 403, and the 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.

[0088] The data stored in the transmission data buffer unit 404 is passed to the encoder unit 405, where it is subjected to encoding such as error correction. There may be data that is directly output from the transmission data buffer unit 404 to the modulation unit 406 without being subjected to encoding. The encoded data is modulated by the modulation unit 406. The modulation unit 406 may perform precoding in MIMO. The modulated data is converted into a baseband signal, and then output to the frequency conversion unit 407, where it is converted into a radio transmission frequency. Thereafter, a transmission signal is transmitted to one or more mobile terminals 202 from the antennas 408-1 to 408-4. Although the case where the number of antennas is four is illustrated in FIG. 9, the number of antennas is not limited to four.

[0089] The reception process of the base station 203 is executed as follows. A radio signal from one or more mobile terminals 202 is received by the antenna 408. The received signal is converted from a radio reception frequency to a baseband signal by the frequency conversion unit 407, and demodulated by the demodulation unit 409. The demodulated data is passed to the decoder unit 410, where decoding such as error correction is performed. Of the decoded data, the control data is passed to the protocol processing unit 403 or the 5GC communication unit 412 or the EPC communication unit 401 and the other base station communication unit 402, and the user data is passed to the 5GC communication unit 412, the EPC communication unit 401, and the other base station communication unit 402. A series of processes of the base station 203 is controlled by the control unit 411. Therefore, although the control unit 411 is omitted in FIG. 9, it is connected to each unit 401 to 410. In FIG. 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.

[0090] Fig. 9 is a block diagram showing the configuration of base station 203, but base station 213 may have a similar configuration. In addition, in Fig. 8 and Fig. 9, the number of antennas of mobile terminal 202 and the number of antennas of base station 203 may be the same or different.

[0091] FIG. 10 is a block diagram showing the configuration of an MME. FIG. 10 shows the configuration of the MME 204a included in the MME unit 204 shown in FIG. 2 described above. The PDN GW communication unit 501 transmits and receives data between the MME 204a and the PDN GW. The base station communication unit 502 transmits and receives data between the MME 204a 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.

[0092] When 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. When 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.

[0093] The control plane control unit 505 includes a NAS security unit 505-1, an SAE bearer control unit 505-2, an idle state mobility management unit 505-3, etc., and performs general 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 idle state (also called the LTE-IDLE state or simply idle), generation and control of paging signals in the idle state, addition, deletion, update, search, and tracking area list management of one or more mobile terminals 202 under its control.

[0094] The MME 204a distributes a paging signal to one or more base stations 203. The MME 204a also performs mobility control in an idle state. The MME 204a manages a tracking area list when a mobile terminal is in an idle state and in an active state. The MME 204a initiates a paging protocol by transmitting a paging message to a cell that belongs to a tracking area in which the UE is registered. The idle state mobility management unit 505-3 may manage the CSG, CSG ID, and whitelist of the eNB 207 connected to the MME 204a.

[0095] FIG. 11 is a block diagram showing the configuration of 5GC. FIG. 11 shows the configuration of the 5GC unit 214 shown in FIG. 3 described above. FIG. 11 shows the case where the 5GC unit 214 shown in FIG. 5 includes the AMF configuration, the SMF configuration, and the UPF configuration. 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 is transmitted to one or more base stations 203 and / or base stations 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.

[0096] 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 control unit 523. The session management unit 527 passes the control data to the control plane control unit 525. If the data received from the base station 203 and / or base station 213 is control data, the control data is passed from the 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.

[0097] The control plane control unit 525 includes a NAS security unit 525-1, a PDU session control unit 525-2, an idle state mobility management unit 525-3, etc., and performs general 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 performs management of 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 a standby state (also called an idle state; RRC_IDLE state, or simply idle), generation and control of paging signals in a standby state, addition, deletion, update, search, tracking area list management, etc. of one or more mobile terminals 202 under its umbrella.

[0098] The 5GC unit 214 distributes paging signals to one or more base stations 203 and / or base station 213. The 5GC unit 214 also performs mobility control in an idle state. The 5GC unit 214 manages a tracking area list when the mobile terminal is in an idle state, an inactive state, and an active state. The 5GC unit 214 initiates a paging protocol by transmitting a paging message to a cell belonging to a tracking area in which the UE is registered.

[0099] Next, an example of a cell search method in a communication system is shown. Fig. 12 is a flow chart showing an outline of a 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, the communication terminal synchronizes slot timing and frame timing using a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS) transmitted from a surrounding base station.

[0100] P-SS and S-SS are collectively called the Synchronization Signal (SS). The Synchronization Signal (SS) is assigned a synchronization code that corresponds one-to-one to the PCI assigned to each cell. 504 different PCIs are being considered. These 504 different PCIs are used to achieve synchronization and to detect (identify) the PCI of the synchronized cell.

[0101] Next, in step ST602, for the synchronized cell, a cell-specific reference signal (CRS), which is a reference signal (RS) transmitted from the base station for each cell, is detected and the RS received power (Reference Signal Received Power: RSRP) is measured. A code that has a one-to-one correspondence with the PCI is used for the reference signal (RS). By correlating with the code, it is possible to separate the cell from other cells. By deriving the code for the RS of the cell from the PCI identified in step ST601, it is possible to detect the RS and measure the RS received power.

[0102] Next, in step ST603, the cell with the best RS reception quality, for example the cell with the highest RS reception power, that is, the best cell, is selected from among one or more cells detected up to step ST602.

[0103] Next, in step ST604, the PBCH of the best cell is received to obtain a BCCH, which is broadcast information. A MIB (Master Information Block), which includes cell configuration information, is mapped to the BCCH on the PBCH. Therefore, the MIB can be obtained by receiving the PBCH and obtaining the BCCH. Examples of MIB information include DL (downlink) system bandwidth (also called transmission bandwidth configuration: dl-bandwidth), the number of transmitting antennas, SFN (System Frame Number), and the like.

[0104] Next, in step ST605, the DL-SCH of the cell is received based on the cell configuration information in the MIB, and SIB (System Information Block) 1 in the broadcast information BCCH is obtained. SIB 1 includes information on access to the cell, information on cell selection, and scheduling information of other SIBs (SIBk; k is an integer ≧2). SIB 1 also includes a tracking area code (TAC).

[0105] 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 that the communication terminal already holds. The tracking area list is also called a TAI list. The TAI is identification information for identifying a tracking area, and is composed of a MCC (Mobile Country Code), an MNC (Mobile Network Code), and a TAC (Tracking Area Code). The MCC is a country code. The MNC is a network code. The TAC is a code number of the tracking area.

[0106] If the TAC received in step ST605 is the same as the TAC included in the tracking area list as a result of the comparison in step ST606, the communication terminal enters standby mode in the cell. If the TAC received in step ST605 is not included in the tracking area list as a result of the comparison, the communication terminal requests a core network (EPC) including an MME, etc., to change the tracking area in order to perform a Tracking Area Update (TAU) through the cell.

[0107] In the example shown in FIG. 12, an example of operations from cell search to standby in the LTE system is shown, but in the NR system, in addition to the best cell, the best beam may be selected in step ST603. Also, in the NR system, beam information, for example, a beam identifier, may be acquired in step ST604. Also, in the NR system, scheduling information of Remaining Minimum SI (RMSI) may be acquired in step ST604. In the NR system, RMSI may be received in step ST605.

[0108] An apparatus constituting a core network (hereinafter sometimes referred to as a "core network side apparatus") updates the tracking area list based on an identification number (such as a UE-ID) of a communication terminal sent from the communication terminal together with a TAU request signal. The core network side apparatus transmits the updated tracking area list to the communication terminal. The communication terminal rewrites (updates) the TAC list held by the communication terminal based on the received tracking area list. After that, the communication terminal enters standby mode in the cell.

[0109] The spread of smartphones and tablet terminal devices has led to an explosive increase in traffic via cellular wireless communications, raising concerns about a shortage of wireless resources around the world. In response to this, efforts are being made to create smaller cells and promote spatial separation in order to improve frequency utilization efficiency.

[0110] In a conventional cell configuration, a cell configured by an eNB has a relatively wide coverage area. Conventionally, a cell is configured to cover a certain area by the relatively wide coverage areas of a plurality of cells configured by a plurality of eNBs.

[0111] In the case of small cell configuration, the cell configured by the eNB has a narrower coverage range than the coverage of the cell configured by the conventional eNB. Therefore, as in the past, in order to cover a certain area, a large number of small cell eNBs are required compared to the conventional eNBs.

[0112] In the following description, a cell with a relatively large coverage, such as a cell configured by a conventional eNB, is referred to as a "macro cell," and an eNB that configures the macro cell is referred to as a "macro eNB." Also, a cell with a relatively small coverage, such as a cell that has been made into a small cell, is referred to as a "small cell," and an eNB that configures the small cell is referred to as a "small eNB."

[0113] The macro eNB may be, for example, a “Wide Area Base Station” as described in Non-Patent Document 7.

[0114] The small eNB may be, for example, a low power node, a local area node, a hotspot, etc. Also, the small eNB may be a pico eNB constituting a pico cell, a femto eNB constituting a femto cell, a HeNB, a remote radio head (RRH), a remote radio unit (RRU), a remote radio equipment (RRE), or a relay node (RN). Also, the small eNB may be a "local area base station" or a "home base station" as described in Non-Patent Document 7.

[0115] FIG. 13 shows an example of a cell configuration in NR. In an NR cell, a narrow beam is formed and transmitted while changing the direction. In the example shown in FIG. 13, at a certain time, the base station 750 transmits and receives with a mobile terminal using a beam 751-1. At another time, the base station 750 transmits and receives with a mobile terminal using a beam 751-2. In the same manner, the base station 750 transmits and receives with a mobile terminal using one or more of the beams 751-3 to 751-8. In this way, the base station 750 configures a wide-range cell.

[0116] 13 shows an example in which the number of beams used by the base station 750 is eight, but the number of beams may be different from eight. Also, in the example shown in FIG. 13, the number of beams used simultaneously by the base station 750 is one, but it may be multiple.

[0117] As an example of a method for satisfying the requirements of ultra reliability, low latency communication (URLLC), packet duplication may be used. The transmitting device may duplicate PDCP PDUs in the PDCP layer and transmit the duplicated PDCP PDUs to the receiving device. The packet duplication may be, for example, packet duplication using DC or packet duplication using CA. In the above, the transmitting device may be a base station or a UE. Also, the receiving device may be a UE or a base station.

[0118] However, in packet duplication, the timing of transferring a received packet to a higher layer is not specified. This causes variations in latency (hereinafter, sometimes referred to as jitter) in data transmission from a transmitting device to a receiving device. For example, when the reception timing of the duplicated packets differs between the two packets, the timing at which the receiving device transfers the packet to a higher layer differs depending on the decoding result (e.g., CRC result) of the packet that is received first. This causes variations in latency in data transmission, resulting in problems such as worsening jitter characteristics.

[0119] Solutions to the aforementioned problems are disclosed below.

[0120] The base station schedules the UE to the same time resource for multiple carriers, which may be, for example, carriers used in packet duplication using CA. The carriers used in packet duplication may be scheduled to the same time resource. For example, inter-carrier scheduling may be used.

[0121] The necessity of scheduling the same time resource for the multiple carriers may be determined in advance by a standard. For example, the necessity of scheduling the same time resource may be determined using QoS parameters. Information on network slicing (e.g., NSSAI (Network Slice Selection Assistance Information)) may be used. The necessity of the scheduling may be determined for each PDU session, for each QoS flow, or for each bearer.

[0122] The QoS parameters may include, for example, information on a transmission cycle of user data (hereinafter, sometimes referred to as Cycle Time) or information on the allowable range of jitter. The information on the allowable range of jitter may be given as a ratio to the Cycle Time or in a specific time unit (e.g., milliseconds or microseconds).

[0123] The QoS parameter may include information about an offset with respect to a transmission period in the transmission timing of user data. The information about the offset may be given as information about a specific time, or as information using a slot number. For the information about the offset, a subframe number or a symbol number may be used.

[0124] The QoS parameters may include only information on the acceptable range of jitter. In the above, the information on the acceptable range of jitter may be given in a specific time unit (e.g., milliseconds or microseconds). This makes it possible to improve the jitter characteristics, for example, in a communication that requires a jitter characteristic, even when periodic data transmission is not performed.

[0125] As another example, the upper network device may determine whether or not the same time resource is scheduled for the multiple carriers. The upper network device may be, for example, an AMF or an SMF. The upper network device may determine whether or not the scheduling is required using a QoS parameter or information related to network slicing. The upper network device may determine whether or not the scheduling is required for each PDU session, for each QoS flow, or for each bearer. The upper network device may notify the base station of information related to whether or not the same time resource is scheduled for the multiple carriers. The notification may be made using an interface between the upper network device and the base station. This makes it possible to reduce the processing time in the base station while improving the jitter characteristics, for example.

[0126] As another example, the base station may determine whether or not to schedule the same time resource for the multiple carriers. The base station may determine whether or not to schedule using QoS parameters or information related to network slicing. The base station may determine whether or not to schedule for each PDU session, each QoS flow, or each bearer.

[0127] Another solution is disclosed. The receiving device transfers the received packet to a higher layer at the reception timing of the packet received later in the packet duplication. The receiving device may be a base station or a UE. That is, the above-mentioned method may be applied in uplink communication or downlink communication.

[0128] The receiving device may hold the previously received packet. The receiving device may hold the previously received packet, for example, until a later packet is received. This allows, for example, the UE to transfer the received packet to a higher layer at the reception timing of the later transmitted packet, regardless of the decoding result of the previously received packet. As a result, it is possible to reduce jitter.

[0129] The retention of the packet in the receiving device may be applied to a bearer for which packet duplication is set. This makes it possible, for example, to improve the jitter characteristics of the packet while preventing an increase in delay of other data. As another example, the retention of the packet in the receiving device may be applied to a bearer for which packet duplication is active. This makes it possible, for example, for a bearer for which packet duplication is set but deactivated, for the receiving device to quickly forward received data to a higher layer.

[0130] The retention of the packet in the receiving device may be performed, for example, in the PDCP layer. The PDCP layer of the receiving device may forward one of the packets to a higher layer using the fact that both duplicated packets have been received in the PDCP layer of the transmitting device. The one of the packets may be the packet received earlier or the packet received later. The receiving device may discard the other packet that has not been forwarded to the higher layer.

[0131] As another example, the retention of the packet in the receiving device may be performed at the RLC layer, for example, data of a logical channel used for packet duplication may be retained.

[0132] As another example, the packet may be stored in the receiving device at the MAC layer. For example, data of a transport block used for transmitting and receiving the packet may be stored. The transport block data may be stored when, for example, a logical channel different from the logical channel used for transmitting and receiving the packet is not mapped to the transport block. This, for example, makes the processing in the receiving device easier.

[0133] As another example of holding the packet in the MAC layer, data of a logical channel used for transmitting and receiving the packet may be held. Logical channel data multiplexed in a transport block received by a receiving device may be held. The receiving device may transfer data of a logical channel different from the above-mentioned logical channel among the logical channel data multiplexed in the transport block to a higher layer without holding it. This makes it possible to prevent, for example, an increase in latency in a logical channel different from the logical channel used for transmitting and receiving the packet.

[0134] As another example, the receiving device may hold the packet in a Service Data Adaptation Protocol (SDAP) layer or in a higher layer, such as an application layer. For example, the receiving device may notify the SDAP layer or the higher layer of information about the packet received later.

[0135] As another example of the retention of the packet in the receiving device, the receiving device may retain only information identifying the packet. For example, the receiving device may retain only the PDCP sequence number of the packet. The receiving device may compare the information of the subsequently received packet with the information retained by the receiving device. The receiving device may forward the subsequently received packet to a higher layer. The forwarding may be performed, for example, when the information identifying the subsequently received packet matches the information retained by the receiving device. This may, for example, reduce the amount of memory used to retain the packet in the receiving device.

[0136] The base station may set for the UE whether the receiving device transfers the packet to the higher layer at the reception timing of the packet received later. For example, RRC signaling, MAC signaling, or L1 / L2 signaling may be used for the setting. As another example of the above setting, the upper NW device may set for the UE via the base station. The upper NW device may be, for example, AMF or SMF. For example, NAS signaling may be used for the setting.

[0137] The setting may include information as to whether the receiving device will forward the packet to a higher layer at the time of receiving the packet later, may include information regarding the bearer used to transmit and receive the packet, may include information regarding the logical channel used to transmit and receive the packet, or may include information regarding the QoS flow through which the packet is transmitted and received.

[0138] The base station may perform the above-mentioned setting using a QoS parameter, or may perform the setting using information on network slicing. For example, when the jitter tolerance included in the QoS parameter is small, the receiving device may transfer the packet to the upper layer at the reception timing of the packet received later. As another example, the upper NW device may perform the above-mentioned setting using a QoS parameter, or may perform the setting using information on network slicing. The QoS parameter may be the same as the QoS parameter disclosed in the solution for scheduling multiple carriers to the same time resource.

[0139] The UE may use the setting to switch the timing of forwarding a received packet to a higher layer. For example, the UE may switch the timing of forwarding a downlink packet to a higher layer from the reception timing of an earlier received packet to the reception timing of a later received packet. The reverse switching may also be performed. This allows, for example, a communication system to flexibly switch between communication requiring jitter characteristics and communication not requiring jitter characteristics.

[0140] The receiving device may forward the received packet to a higher layer regardless of the setting. The forwarding may be performed, for example, when MAC signaling including an instruction for deactivation of packet duplication is received. When the receiving device (e.g., UE) receives the MAC signaling from the base station, it may forward the received packet held in the UE to a higher layer. The received packet may be, for example, a packet received earlier in packet duplication. This makes it possible to reduce the amount of memory storage after packet duplication is stopped, for example.

[0141] Fig. 14 is a diagram showing an operation of a receiving device in the first embodiment, in which the receiving device transfers a packet to a higher layer at the reception timing of the packet transmitted later among the duplicated packets. Fig. 14 shows a case where the duplicated packets are respectively mapped to logical channels (Logical CHannel; LCH) #1 and #2. Fig. 14 also shows a case where CA is used for packet duplication. In Fig. 14, a period in which data is transmitted from a transmitting device is shown as Cycle Time.

[0142] In Fig. 14, the receiving device receives packet 1401 from LCH#1 and packet 1402 from LCH#2. Packets 1401 and 1402 are identical packets that have been duplicated by packet duplication. In Fig. 14, the receiving device receives packet 1401 first. The receiving device holds packet 1401 until it receives packet 1402 from LCH#2 (see the dashed arrow in Fig. 14). The receiving device transfers packet 1401 to a higher layer at the timing of receiving packet 1402 (see the thick arrow in Fig. 14). The receiving device discards packet 1402 received later.

[0143] 14, after the Cycle Time has elapsed since the reception of packets 1401 and 1402, the receiving device receives packet 1403 from LCH#1 and packet 1404 from LCH#2. Packets 1403 and 1404 are identical packets that have been duplicated by packet duplication. The operation of the receiving device is the same as that when packets 1401 and 1402 are received.

[0144] 14, after the Cycle Time has elapsed since the reception of packets 1403 and 1404, the receiving device receives packet 1405 from LCH#1 and packet 1406 from LCH#2. Packets 1405 and 1406 are identical packets that have been duplicated by packet duplication. The operation of the receiving device is the same as that when packets 1401 and 1402 are received.

[0145] In Fig. 14, after the Cycle Time has elapsed since the reception of packets 1405 and 1406, the receiving device receives packet 1407 from LCH#1 and packet 1408 from LCH#2. Packets 1407 and 1408 are identical packets that have been duplicated by packet duplication. In the example shown in Fig. 14, the receiving device receives packet 1408 first. The receiving device holds packet 1408 until it receives packet 1407 from LCH#1. The receiving device transfers packet 1408 to a higher layer at the timing of receiving packet 1407. The receiving device discards packet 1407 received later.

[0146] Although an example in which CA is used for packet duplication is shown in FIG. 14, DC may also be used for packet duplication. In the case of packet duplication using DC, LCHs #1 and #2 in FIG. 14 may be used in the master base station and the secondary base station, respectively. LCHs #1 and #2 may also be used in the secondary base station and the master base station, respectively. This makes it possible to maintain communication between the UE and one base station even if the communication path between the UE and the other base station is interrupted (for example, by blocking). As a result, it is possible to improve the reliability of communication.

[0147] FIG. 14 shows an operation in which the receiving device holds a previously received packet. However, the receiving device may hold only the identifier of the previously received packet. The identifier may be, for example, a PDCP sequence number. For example, the receiving device may hold the PDCP sequence number of a previously received packet 1401. The receiving device may discard information other than the PDCP sequence number of packet 1401. The receiving device may check the PDCP sequence number of a subsequently received packet 1402 against the PDCP sequence number it holds. For example, when the PDCP sequence number matches the PDCP sequence number it holds, the receiving device may forward packet 1402 to an upper layer. Packets 1403 and 1404 may be treated in the same manner as packets 1401 and 1402. Packets 1405 and 1406 may be treated in the same manner as packets 1401 and 1402. Packets 1408 and 1407 may be treated in the same manner as packets 1401 and 1402. In the above, the operation on the receiving device regarding packet 1401 may be applied to packet 1408, and the operation on packet 1402 may be applied to packet 1407. This makes it possible to reduce, for example, the memory usage in the receiving device.

[0148] When the above-mentioned operation is applied in the receiving device, the following problem occurs. That is, if the receiving device cannot receive a packet whose reception timing is later, for example, if a decoding error occurs when receiving the packet, the receiving device cannot transfer the received packet to a higher layer unless it waits for a retransmission of the packet (for example, HARQ retransmission). This causes problems such as increased latency and worsening jitter characteristics.

[0149] A method for solving the above problems is disclosed.

[0150] The receiving device transfers a received packet to a higher layer at a predetermined timing. The receiving device may hold a previously received packet until that timing. The receiving device may hold a subsequently received packet until that timing, or may discard it. The receiving device may transfer a previously received packet to a higher layer, for example, when a predetermined timing has passed. In the receiving device, transfer to the higher layer after the predetermined timing has passed may be performed immediately after receiving the packet.

[0151] The retention of the packet in the receiving device may be applied to a bearer for which packet duplication is set. This makes it possible, for example, to improve the jitter characteristics of the packet while preventing an increase in delay of other data. As another example, the retention of the packet in the receiving device may be applied to a bearer for which packet duplication is active. This makes it possible, for example, for a bearer for which packet duplication is set but deactivated, for the receiving device to quickly forward received data to a higher layer.

[0152] The packet may be stored in the receiving device at the PDCP layer or at the RLC layer. For example, data of a logical channel used for packet duplication may be stored.

[0153] As another example, the packet may be stored in the receiving device at the MAC layer. For example, data of a transport block used for transmitting and receiving the packet may be stored. The transport block data may be stored when, for example, a logical channel different from the logical channel used for transmitting and receiving the packet is not mapped to the transport block. This, for example, makes the processing in the receiving device easier.

[0154] As another example of holding the packet in the MAC layer, data of a logical channel used for transmitting and receiving the packet may be held. Logical channel data multiplexed in a transport block received by a receiving device may be held. The receiving device may transfer data of a logical channel different from the above-mentioned logical channel among the logical channel data multiplexed in the transport block to a higher layer without holding it. This makes it possible to prevent, for example, an increase in latency in a logical channel different from the logical channel used for transmitting and receiving the packet.

[0155] As another example, the receiving device may hold the packet in a Servide Data Adaptation Protocol (SDAP) layer or in a higher layer, such as an application layer. For example, the receiving device may notify the SDAP layer or the higher layer of information about the packet received later.

[0156] The receiving device may transfer the packet to the upper layer at the timing that arrives first between the predetermined timing and the reception timing of the subsequently received packet. This, for example, makes it possible to reduce memory consumption in the receiving device. In the above, the upper layer may hold the packet until the predetermined timing. The holding may be performed, for example, when the reception timing of the subsequently received packet arrives before the predetermined timing. This, for example, makes it possible to improve the jitter characteristics in the transmission and reception of the packet.

[0157] The timing may be determined by the base station. The base station may notify the UE of information regarding the timing. In notifying the UE of the timing from the base station, RRC signaling, MAC signaling, or L1 / L2 signaling may be used. The UE may forward the received packet to a higher layer using the information. As another example of the operation in the UE, the UE may transmit a duplicated packet to the base station using the information. For example, the UE may transmit the duplicated packet to the base station so that the base station can forward the received packet to the higher layer in time for the timing.

[0158] As another example, the timing may be determined by an upper NW device. The upper NW device may be an AMF or an SMF. The upper NW device may notify the UE of information regarding the timing via a base station. For example, NAS signaling may be used for the notification.

[0159] As another example, the UE may determine the timing. The UE may notify the base station of information regarding the timing. The base station may approve or deny the timing determined by the UE. As another example, the base station may notify the upper NW device of the timing determined by the UE. The upper NW device may approve or deny the timing determined by the UE. In notifying the information from the UE to the base station and / or the upper NW device, NAS signaling, RRC signaling, MAC signaling, or L1 / L2 signaling may be used. This allows, for example, the UE that is the source of transmission to determine the timing when transmitting uplink data. As a result, efficiency in the communication system can be improved.

[0160] The information on the predetermined timing may be given, for example, by a slot number. The receiving device may transfer the received packet to the upper layer in the slot corresponding to the given number. As another example, the information may be given using information identifying a non-slot (sometimes called a mini-slot), for example, the number of the non-slot. The receiving device may transfer the received packet to the upper layer in the non-slot corresponding to the given number. The information may be given in units of symbols. The receiving device may transfer the received packet to the upper layer in the symbol corresponding to the given number. This makes it possible to improve the jitter characteristics, for example, even when data transmission and reception are scheduled in units shorter than one slot. The information on the predetermined timing may be given by a combination of the above-mentioned numbers. For example, the information may be given by a combination of a slot number and a symbol number. This makes it possible to improve the jitter characteristics, for example, even when communication requiring jitter tolerance is not performed in one slot period.

[0161] The information on the predetermined timing may include information on a period. The information may be, for example, the cycle time shown in Non-Patent Document 23 (3GPP TR22.804 V16.1.0). The information may be given in absolute time, for example, in millisecond units, in subframe units, in slot units, in symbol units, or in non-slot units. The receiving device may use the information to derive the timing for transferring the received packet to the upper layer. The receiving device may transfer the received packet to the upper layer at the derived timing. This makes it unnecessary for the upper NW device or the base station to notify the UE of the timing for transferring the received packet to the upper layer for each packet. As a result, it is possible to reduce the amount of signaling between the upper NW device or the base station and the UE.

[0162] The information on the predetermined timing may include both information on the period and information on the offset. The information on the offset may be provided, for example, on a subframe basis, a slot basis, a symbol basis, or a non-slot basis. The receiving device may use the information to derive the timing for transferring the received packet to a higher layer. The receiving device may transfer the received packet to a higher layer at the derived timing. This, for example, makes it possible to avoid complexity in the process of deriving the timing in the receiving device in addition to the above-mentioned effects.

[0163] The base station may set for the UE whether the receiving device transfers to a higher layer at a predetermined timing. For example, RRC signaling, MAC signaling, or L1 / L2 signaling may be used for the setting. As another example of the above setting, an upper NW device may set for the UE via the base station. The upper NW device may be, for example, AMF or SMF. For example, NAS signaling may be used for the setting.

[0164] The information about the predetermined timing may be included in the QoS parameter. For example, a correspondence may be established between the information about the predetermined timing and an identifier of the QoS parameter. The QoS parameter may be the same as the QoS parameter disclosed in the solution for scheduling multiple carriers to the same time resource.

[0165] The above-mentioned setting using the QoS parameters may be performed by the base station for the UE, or may be performed by the upper NW device for the UE via the base station. As another example, the upper NW device may notify the base station of the QoS parameters. The base station may extract information regarding a predetermined timing using the QoS parameters. The base station may notify the UE of the information regarding the predetermined timing.

[0166] The UE may use the setting to switch the timing of forwarding a received packet to a higher layer. For example, the UE may switch the timing of forwarding a downlink packet to a higher layer from the reception timing of a first received packet to a predetermined timing. The reverse switching may be performed. As another example, the UE may switch the timing of forwarding a downlink packet to a higher layer from the reception timing of a later received packet to a predetermined timing. The reverse switching may be performed. As another example, the UE may change the predetermined timing used for forwarding a downlink packet to a higher layer. This makes it possible to flexibly switch between communication requiring a jitter characteristic and communication not requiring a jitter characteristic in a communication system.

[0167] The receiving device may discard received data that is out of the jitter tolerance range. The receiving device may use, for example, QoS parameters to determine whether the received data is within the jitter tolerance range. This makes it possible to prevent malfunctions caused by data that is out of the jitter tolerance range in services using a communication system, for example.

[0168] The base station may change the predetermined timing. For example, the transmission period may be changed, or an offset to the transmission period may be changed. The base station may determine the changed predetermined timing and notify the UE. As another example, the UE may determine the changed predetermined timing and notify the base station. The base station may determine the timing notified by the UE. This makes it possible to improve the flexibility of scheduling while ensuring the jitter characteristics in the communication system, for example.

[0169] The changed timing may be determined using the reception timing in the receiving device. For example, the changed timing may be determined using a moving average of the reception timing in the receiving device. The calculation of the changed timing may be performed periodically, or may be performed using an instruction from the base station or an upper NW device. The period for calculating the changed timing may be determined by a standard, or the upper NW device may notify the base station and / or UE, or the base station may determine and notify the UE. This makes it possible to determine the predetermined timing using the timing actually received in the communication system, and as a result, it is possible to improve the jitter characteristics.

[0170] As another example of the notification of a predetermined timing, the transmitting device may notify information on the transmission time of the transmission data, or may notify information on the time when the receiving device should receive the data. The time when the data should be received may be, for example, the time when the receiving device should transfer the data to the upper layer. The time may be, for example, a time in milliseconds, a time using a subframe number, a time using a slot number, a time using a minislot number, a time using a symbol number, or a combination of two or more of the above. The transmitting device may, for example, give a timestamp to the transmission data. The timestamp may be information similar to the above-mentioned time. The timestamp may be given in the upper layer, in the SDAP, in the PDCP, in the RLC, or in the MAC. As another example, the information on the transmission time and / or the information on the time when the data should be received may be notified using RRC signaling, in the MAC signaling, or in the L1 / L2 signaling. The receiving device may derive the predetermined timing using information about the transmission time and / or the time to receive. The receiving device may remove the timestamp in the received data. The method for notifying the predetermined timing may be used, for example, for non-periodic data transmission and reception. This makes it possible, for example, to keep the latency constant even in non-periodic data transmission and reception. That is, it makes it possible to reduce jitter.

[0171] The receiving device may forward the received packet to a higher layer regardless of the setting. The forwarding may be performed, for example, when MAC signaling including an instruction for deactivation of packet duplication is received. When the receiving device (e.g., UE) receives the MAC signaling from the base station, the receiving device may forward the received packet held in the UE to a higher layer. The forwarding operation may be performed, for example, before the timing described above. This makes it possible to reduce the amount of memory storage after packet duplication is stopped.

[0172] In packet duplication, the receiving device may not request the transmitting device to retransmit a packet whose reception result is not normal (e.g., a decoding error). The retransmission may be, for example, a HARQ retransmission or an RLC retransmission. The above operation may be performed when the decoding result of one of the duplicated packets is normal. This can improve the efficiency of the communication system. The HARQ entity of the receiving device may consider the decoding result of the packet whose reception result is not normal as OK. The RLC layer of the receiving device may consider the packet as an ACK. For example, the RLC layer of the receiving device may advance the receiving window.

[0173] Fig. 15 is a diagram showing an operation of a receiving device transferring a received packet to a higher layer at a predetermined timing in the first embodiment. Fig. 15 shows a case where the copied packets are mapped to logical channels (LCH) #1 and #2, respectively. Fig. 15 also shows a case where CA is used for packet copying. In Fig. 15, the period during which data is transmitted from the transmitting device is shown as Cycle Time. In Fig. 15, elements common to Fig. 14 are given the same numbers, and common explanations will be omitted.

[0174] 15, the receiving device first receives packet 1401. The receiving device transfers packet 1401 to a higher layer at a predetermined timing (see the timing indicated by the dashed line in FIG. 15) immediately after receiving packet 1401. The receiving device receives packet 1402. The receiving device discards packet 1402 received later.

[0175] In Fig. 15, after the Cycle Time has elapsed since the reception of packets 1401 and 1402, the receiving device receives packets 1403 and 1404. The receiving device receives packet 1403 first. The receiving device holds packet 1403 and attempts to receive packet 1404 which is transmitted later. The example shown in Fig. 15 illustrates a case where the reception result of packet 1404 by the receiving device is a decoding error. The receiving device transfers packet 1403 to a higher layer at a predetermined timing. After that, the receiving device receives packet 1404 which has been retransmitted by HARQ. The receiving device discards packet 1404 which was received later.

[0176] In Fig. 15, after the Cycle Time has elapsed since the reception of packets 1403 and 1404, the receiving device receives packets 1405 and 1406. The receiving device receives packet 1405 first and holds it. The receiving device receives packet 1406 later. The receiving device discards packet 1406, which was received later. The example shown in Fig. 15 shows a case where a predetermined timing exists after the reception timing of packets 1405 and 1406. The receiving device transfers packet 1405 to an upper layer at the predetermined timing.

[0177] 15, after the Cycle Time has elapsed since the reception of packets 1405 and 1406, the receiving device receives packet 1407 from LCH#1 and packet 1408 from LCH#2. Of packets 1407 and 1408, in the example shown in FIG. 15, the receiving device receives packet 1408 first. The receiving device holds packet 1408. The receiving device transfers packet 1408 to an upper layer at a predetermined timing. The receiving device receives packet 1407, which is transmitted later, and discards it.

[0178] In Fig. 15, an example in which CA is used for packet duplication is shown, but DC may be used for packet duplication as in Fig. 14. This makes it possible to maintain communication between the UE and one base station even if the communication path between the UE and the other base station is interrupted (for example, by blocking). As a result, it is possible to improve the reliability of communication.

[0179] The solution disclosed in the first embodiment may be applied to uplink transmission and reception using a configured grant, or may be applied to downlink transmission and reception using a configured scheduling allocation. In uplink communication, both packets copied by packet duplication may be transmitted and received using the configured grant. In addition, in uplink communication, one packet may be transmitted and received using the configured grant, and the other packet may be transmitted and received using a dynamic grant. In downlink communication, both packets copied by packet duplication may be transmitted and received using the configured scheduling allocation. In addition, one packet may be transmitted and received using the configured scheduling allocation, and the other packet may be transmitted and received using a dynamic scheduling allocation. This allows the base station to flexibly perform scheduling in packet duplication, for example.

[0180] In packet duplication using the configured grant and / or the configured scheduling allocation, the receiving device may forward the received packet to the upper layer at the reception timing of the subsequently received packet. The receiving device may forward the received packet to the upper layer regardless of the reception result (e.g., the decoding result) of the subsequently received packet. For example, the receiving device may forward the previously received packet to the upper layer even if the subsequently received packet has a decoding error. The receiving device may derive the timing of the subsequently transmitted packet using the configured grant or the configured scheduling allocation used in the logical channel that transmits and receives the subsequently received packet. The above-mentioned operation may be applied when the subsequently received packet is transmitted and received using the configured grant in the upstream communication, or when the subsequently received packet is transmitted and received using the configured scheduling allocation in the downstream communication. In addition, the above-mentioned operation may be performed when the reception result of the previously received packet is normal (e.g., the decoding result is normal). As a result, for example, even if the subsequently received packet at the receiving device has a decoding error, the receiving device can forward the packet to the upper layer without waiting for HARQ retransmission. As a result, the jitter characteristics can be improved.

[0181] The receiving device may not request the transmitting device to retransmit a packet with an abnormal reception result (e.g., a decoding error) in packet duplication using the configured grant and / or the configured scheduling allocation. The retransmission may be, for example, a HARQ retransmission or an RLC retransmission. The above operation may be performed when the decoding result of one of the duplicated packets is normal. This can improve the efficiency of the communication system. The HARQ entity of the receiving device may consider the decoding result of the packet with an abnormal reception result as OK. The RLC layer of the receiving device may consider the packet as an ACK. For example, the RLC layer of the receiving device may advance the receiving window.

[0182] FIG. 16 is a diagram showing another example of the operation of the receiving device in the first embodiment, in which the receiving device transfers a packet to a higher layer at the reception timing of the packet transmitted later among the duplicated packets. FIG. 16 shows a case where the duplicated packets are mapped to logical channels (Logical CHannel; LCH) #1 and #2, respectively. FIG. 16 shows a case where the configured scheduling allocation is performed for LCH #1 and #2, respectively. In FIG. 16, the area surrounded by a square indicates the time resource allocated by the configured scheduling allocation, and the area with the left-downward diagonal line indicates the timing when the duplicated packet is transmitted. FIG. 16 also shows a case where CA is used for packet duplication. In FIG. 16, the period in which data is transmitted from the transmitting device is shown as Cycle Time. In FIG. 16, the same numbers are assigned to elements common to FIG. 15, and the common description is omitted.

[0183] In Fig. 16, the receiving device simultaneously receives a packet 1601 transmitted from LCH#1 and a packet 1602 transmitted from LCH#2. Packets 1601 and 1602 are identical packets that have been duplicated by packet duplication. The receiving device forwards packet 1601 to an upper layer. The receiving device discards packet 1602.

[0184] 16, after the Cycle Time has elapsed since the reception of packets 1601 and 1602, the receiving device receives packet 1603 from LCH#1 before packet 1604 from LCH#2. Packets 1603 and 1604 are identical packets that have been duplicated by packet duplication. The receiving device holds packet 1603. Upon receiving packet 1604, the receiving device forwards packet 1603 to an upper layer. The receiving device discards packet 1604.

[0185] 16, after the Cycle Time has elapsed since the reception of packets 1603 and 1604, the receiving device receives packet 1606 from LCH#2 before packet 1605 from LCH#1. Packets 1605 and 1606 are identical packets that have been duplicated by packet duplication. The receiving device holds packet 1606. Upon receiving packet 1605, the receiving device forwards packet 1606 to an upper layer. The receiving device discards packet 1605.

[0186] 16, after the Cycle Time has elapsed since the reception of packets 1605 and 1606, the receiving device receives packet 1607 from LCH#1 before packet 1608 from LCH#2. Packets 1607 and 1608 are identical packets that have been duplicated by packet duplication. The receiving device holds packet 1607. Upon receiving packet 1608, the receiving device forwards packet 1607 to an upper layer. The receiving device discards packet 1608.

[0187] In Fig. 16, an example in which CA is used for packet duplication is shown, but DC may be used for packet duplication as in Fig. 14 and Fig. 15. This makes it possible to maintain communication between the UE and one base station even when a communication path between the UE and the other base station is interrupted (for example, by blocking), thereby making it possible to improve the reliability of communication.

[0188] FIG. 16 shows a case where a configured scheduling assignment is performed for each of LCH#1 and #2. However, a configured scheduling assignment may be performed for one of LCH#1 and LCH#2, and a dynamic scheduling assignment may be performed for the other. The above-mentioned assignment may be performed for downlink communication. As another example, a configured grant may be performed for each of LCH#1 and #2. Alternatively, a configured grant may be performed for one of LCH#1 and LCH#2, and a dynamic grant may be performed for the other. The above-mentioned grant may be performed for uplink communication. This allows the base station to flexibly perform scheduling, for example, in packet duplication.

[0189] FIG. 16 shows a case where the reception results (e.g., decoded results) of packets 1601 to 1608 are all normal. However, even if the subsequently received packet has a reception error (e.g., a CRC error), the receiving device may transfer the previously received packet to a higher layer. The above-mentioned operation may be applied, for example, to a case where the subsequently received packet is transmitted using a configured scheduling allocation, or a case where the subsequently received packet is transmitted using a configured grant. In the above-mentioned case, the receiving device may not request HARQ retransmission from the transmitting device, or may not request RLC retransmission. This, for example, can improve the jitter characteristics and improve the efficiency in the communication system.

[0190] The configured grant and / or configured scheduling allocation for transmitting each replicated packet may have the same timing. The timing may, for example, have the same period or the same timing offset. The period may, for example, be the same as the transmission period of the replicated packets. The timing offset may, for example, be the same as the above-mentioned predetermined timing. This allows, for example, jitter reduction to be performed with a small amount of processing in the communication system.

[0191] Information regarding the timing at which the configured grant and / or the configured scheduling assignment is performed may be notified between base stations. The notification may include, for example, information regarding a period or information regarding a timing offset. The notification may be performed, for example, in packet duplication using DC. The master base station may notify information regarding the timing to the secondary base station. The secondary base station may use the information to determine the timing.

[0192] The transmission and reception of both duplicated packets may be performed during a part of the timing when the configured grant and / or the configured scheduling assignment is performed. For example, when the period of the configured grant and / or the configured scheduling assignment is different from the period of the duplicated packet, the transmission and reception of both duplicated packets may be performed using a part of the timing. This makes it possible to transmit and receive the packets using the configured grant and / or the configured scheduling assignment even when the configured grant and / or the configured scheduling assignment cannot be secured according to the period of the duplicated packet in the communication between the base station and the UE.

[0193] The information on the part of timing may be predetermined by a standard. For example, the transmission and reception of the replicated packet may be performed at a timing when a configured grant and / or a configured scheduling assignment is performed that is closest to the predetermined timing for the transmission and reception of the replicated packet. Alternatively, the transmission and reception may be performed at a timing closest to the predetermined timing or at a timing closest to the predetermined timing.

[0194] The above methods may be used in combination. For example, in the case where a configured grant and / or a configured scheduling assignment exists at equal intervals before and after the predetermined timing as the timing immediately before the predetermined timing, the configured grant and / or the configured scheduling assignment existing before the predetermined timing may be used. As another example, the configured grant and / or the configured scheduling assignment existing after the predetermined timing may be used.

[0195] As another example, the base station may determine information about the aforementioned part of timing and notify the UE. The notification from the base station to the UE may include, for example, information about the grant and / or allocation used for transmitting and receiving the duplicated packet, among the configured grant and / or configured scheduling allocation. The information may include, for example, information about the pattern of the grant and / or allocation used for transmitting and receiving the packet. The information about the pattern may be, for example, bitmap information indicating whether or not it is used for transmitting and receiving the packet, or may be information in another format. As another example of the information about the grant and / or allocation used for transmitting and receiving the duplicated packet, information about the period of the pattern may be included, or information about the validity period of the pattern may be included.

[0196] For example, RRC signaling may be used for the notification of information regarding some timings. This allows, for example, a base station to notify the UE of a large amount of information, and as a result, flexibility in the communication system can be improved. As another example, MAC signaling may be used for the notification. This allows, for example, the base station to notify the UE of a large amount of information by multi-level modulation, and allows the base station to quickly notify the UE of the information. As another example, L1 / L2 signaling may be used for the notification of the information. This allows, for example, the base station to more quickly notify the UE of the information.

[0197] The operation of the receiving device transferring a received packet to a higher layer at a predetermined timing may be applied when a configured grant or configured scheduling allocation is performed. The operation in the receiving device and the notification of the timing from the higher NW device or the base station to the UE may be the same as the method disclosed in the first embodiment. The notification of the timing from the UE to the base station or the higher NW device may also be the same. This makes it possible to further improve the jitter characteristics, for example.

[0198] The receiving device may apply an operation of transferring the packet to the upper layer at the earlier of the predetermined timing and the reception timing of the subsequently received packet when the configured grant or the configured scheduling allocation is performed. This, for example, makes it possible to reduce memory consumption in the receiving device. In the above, the upper layer may hold the packet until the predetermined timing. The holding may be performed, for example, when the reception timing of the subsequently received packet arrives before the predetermined timing. This, for example, makes it possible to improve the jitter characteristics in the transmission and reception of the packet.

[0199] FIG. 17 is a diagram showing another example of the operation of the receiving device in the first embodiment, in which the receiving device transfers the received packet to the upper layer at a predetermined timing. FIG. 17 shows a case where the duplicated packets are mapped to the logical channels (LCH) #1 and #2, respectively. FIG. 17 shows a case where the pre-configured scheduling allocation is performed for LCH #1 and #2, respectively. In FIG. 17, the rectangular area shows the time resource allocated by the pre-configured scheduling allocation, and the area with the left-downward diagonal line shows the timing when the duplicated packet is transmitted. FIG. 17 also shows a case where CA is used for packet duplication. In FIG. 17, the period in which data is transmitted from the transmitting device is shown as Cycle Time. In FIG. 17, the same numbers are assigned to the elements common to FIG. 16, and the common explanation is omitted.

[0200] The operation of the receiving device with respect to packets 1601 and 1602 in Fig. 17 is the same as that in Fig. 16. Also, the operation of the receiving device with respect to packets 1603 and 1604 is the same as that in Fig. 16. Note that in Fig. 17, the timing at which the receiving device receives packets 1601 and 1602 coincides with a predetermined timing. Also, the timing at which the receiving device receives packet 1604 coincides with a predetermined timing.

[0201] In Fig. 17, after the Cycle Time has elapsed since the reception of packets 1603 and 1604, the receiving device receives packet 1606 from LCH #2 before packet 1605 from LCH #1. In Fig. 17, the timing at which the receiving device receives packet 1606 coincides with a predetermined timing. The receiving device transfers packet 1606 to an upper layer at the same time as receiving packet 1606. The receiving device receives packet 1605 after that timing. The receiving device discards packet 1605.

[0202] The operation of the receiving device with respect to packets 1607 and 1608 in Fig. 17 is the same as that in Fig. 16. Note that in Fig. 17, the timing at which the receiving device receives packet 1608 coincides with a predetermined timing.

[0203] Although an example in which CA is used for packet duplication is shown in Fig. 17, DC may be used for packet duplication as in Fig. 14, Fig. 15, and Fig. 16. This makes it possible to maintain communication between the UE and one base station even when a communication path between the UE and the other base station is interrupted (for example, by blocking), thereby making it possible to improve the reliability of communication.

[0204] In Fig. 17, a case where a pre-configured scheduling assignment is performed for each of LCHs #1 and #2 is shown. However, as in Fig. 16, a pre-configured grant may be performed for both LCHs #1 and #2, or a pre-configured scheduling assignment or pre-configured grant may be performed for only one of the LCHs. This allows the base station to flexibly perform scheduling in the case of packet duplication, for example.

[0205] FIG. 17 shows a case where the reception results (e.g., decoded results) of packets 1601 to 1608 are all normal. However, similar to FIG. 16, even if the subsequently received packet has a reception error (e.g., a CRC error), the receiving device may transfer the previously received packet to a higher layer. The above-mentioned operation may be applied, for example, to a case where the subsequently received packet is transmitted using a configured scheduling allocation, or a case where the subsequently received packet is transmitted using a configured grant. In the above-mentioned case, the receiving device may not request HARQ retransmission from the transmitting device, and may not request RLC retransmission. This, for example, can improve the jitter characteristics and improve the efficiency in the communication system.

[0206] 17 shows a case where the reception timings of packets 1601, 1602, 1604, 1606, and 1608 at the receiving device coincide with the predetermined timing. However, the reception timings of packets 1601, 1602, 1604, 1606, and 1608 do not have to coincide with the predetermined timing. For example, when the reception timing of packet 1604 is earlier than the predetermined timing, the receiving device may hold packet 1603 until the predetermined timing. The receiving device may receive packet 1604. The receiving device may discard packet 1604. This makes it possible to further improve the jitter characteristics, for example.

[0207] The packet duplication used in the first embodiment may be, for example, using a side link. For example, one of the duplicated packets may be transmitted using a Uu interface, and the other packet may be transmitted using an end-to-end interface (e.g., PC5 interface). As another example, both of the duplicated packets may be transmitted and received using an end-to-end interface (e.g., PC5 interface). This makes it possible to reduce jitter, for example, in side link communication as well.

[0208] According to the first embodiment, it is possible to improve the jitter characteristics while ensuring the reliability of the communication between the base station and the UE.

[0209] Variation 1 of the first embodiment In the first embodiment, a method for improving jitter characteristics in packet duplication using CA or DC has been disclosed, but packet duplication using the same carrier may be used. The packet duplication may be provided as a new packet duplication different from the packet duplication using DC or CA.

[0210] The two duplicated packets may be mapped to different transport blocks and transmitted, or each transport block may be mapped to the same carrier and transmitted, which can improve reliability even in communications using only one carrier, for example.

[0211] The transmitting device may map each of the duplicated packets to a different transport block. The transmitting device may be a base station or a UE. The transmitting device may transmit each of the physical channel data generated by encoding each transport block by arranging the data in different frequency and / or time resources, or in different layers in MIMO.

[0212] The receiving device may extract each physical channel signal generated from both of the duplicated packets using the received signal. The receiving device may be a UE or a base station. The receiving device may decode each of the physical channel signals into each transport block. The receiving device may generate each of the duplicated packets using each of the physical channel signals. For example, the receiving device may generate each packet using each of the transport blocks. The receiving device may transfer any one of the duplicated packets to a higher layer. The receiving device may discard packets other than the packet transferred to the higher layer among the duplicated packets.

[0213] The receiving device may not request HARQ retransmission of only one of the transport blocks. For example, when the decoding result (e.g., CRC result) of one transport block is normal in the receiving device and the decoding of the other transport block is NG, the receiving device may not transmit HARQ-NACK to the transmitting device. The receiving device may regard the other transport block as HARQ-ACK. The receiving device may transmit HARQ-ACK for the other transport block to the transmitting device. As another example, the receiving device may transmit HARQ-NACK for the other transport block to the transmitting device. The transmitting device may not perform HARQ retransmission for the other transport block by using the reception of HARQ-ACK for one transport block and the reception of HARQ-NACK for the other transport block. This makes it possible to improve the efficiency of the communication system, for example.

[0214] The receiving device may also regard one of the duplicated packets, for which the reception result was NG, as having a reception result of OK. This operation may be performed, for example, in the RLC layer.

[0215] The base station may set the UE regarding packet duplication using the same carrier, or the upper network device may set the UE regarding packet duplication using the same carrier.

[0216] The setting may include information indicating whether or not packet duplication using the same carrier is performed, and may include information regarding the start or stop of packet duplication using the same carrier, which makes it possible to flexibly control packet duplication using the same carrier, for example.

[0217] The configuration may include information regarding feedback from the receiving device to the base station device, which may be determined using, for example, QoS parameters or information regarding network slicing.

[0218] The information may include information regarding the processing of the receiving side device. For example, the information may include information indicating that a HARQ response is not made to the transport block that was decoded NG, or may include information indicating that a HARQ-NACK response is made to the transport block, or may include information indicating that a HARQ-ACK response is made to the transport block. The above information may be applied when one of the transport blocks is decoded OK. As another example, the information regarding the processing of the receiving side device may include information in which the above-mentioned HARQ response is replaced with an ARQ response of RLC. This makes it possible to improve the efficiency in the communication system, for example, by not making a HARQ response.

[0219] The information on the feedback may include information on the processing in the transmitting side device. For example, the information may include information indicating that the transmitting side device does not perform HARQ retransmission for the transport block for which decoding was NG, or may include information indicating that the transmitting side device does not perform HARQ retransmission for the transport block for which there was no HARQ response. The above information may be applied when a HARQ-ACK for one of the transport blocks is received. As another example, the information on the processing in the transmitting side device may include information in which the above-mentioned HARQ retransmission is replaced with RLC retransmission. This makes it possible to improve the efficiency in the communication system, for example, by not performing HARQ retransmission.

[0220] The configuration may include information on a method for arranging transport blocks. The following items (1) to (5) are disclosed as information on a method for arranging transport blocks.

[0221] (1) Divided allocation of frequency resources.

[0222] (2) Dividing time resources into smaller allocations.

[0223] (3) Separate layer arrangement in MIMO.

[0224] (4) Separate code arrangement in code multiplexing.

[0225] (5) A combination of (1) to (4) above.

[0226] The information (1) above may include information on the frequency resource in which one of the duplicated packets is allocated. The information may include, for example, information on the first RB (Resource Block) in which the packet is allocated, information on the number of RBs in which the packet is allocated, or information on the last RB number in which the packet is allocated. This makes it possible to reduce the amount of information on the allocation of the packet, for example. As a result, it is possible to improve the efficiency of the communication system.

[0227] As another example, the information (1) above may include information on the allocation pattern of the frequency resource in which one of the duplicated packets is allocated. The information on the allocation pattern may include, for example, information on the period of the allocation pattern, or information on an offset with respect to the period. The one of the packets may be transmitted in the frequency resource corresponding to the offset. As another example, information on a bitmap representing the allocation pattern may be used. This makes it possible to allocate the duplicated packets discretely in the frequency direction, for example. As a result, it becomes possible to obtain the effect of frequency diversity.

[0228] In the above (1), the information on the frequency resource in which the other of the duplicated packets is allocated may be the same as the information on the frequency resource in which one of the duplicated packets is allocated. This makes it possible to flexibly allocate frequency resources in both of the duplicated packets in a communication system, for example.

[0229] As another example, in the above (1), the information on the frequency resource in which the other of the duplicated packets is allocated may be frequency resources excluding the frequency resource in which one of the packets is allocated among the frequency and / or time resources granted and / or scheduled by the base station. This makes it possible to reduce, for example, the amount of signaling from the base station and / or the upper NW device to the UE. As a result, it is possible to improve the efficiency of the communication system.

[0230] The information (2) above may include information about a time resource in which one of the duplicated packets is placed. The information may include, for example, information about the first symbol number in which the packet is placed, information about the number of symbols in which the packet is placed, or information about the last symbol number in which the packet is placed. This makes it possible to reduce the amount of information about the placement of the packets, for example. As a result, it is possible to improve the efficiency of the communication system.

[0231] As another example, the information (2) above may include information on the allocation pattern of the time resource in which one of the duplicated packets is allocated. The information on the allocation pattern may include, for example, information on the period of the allocation pattern, or information on an offset with respect to the period. The one of the packets may be transmitted in the time resource corresponding to the offset. As another example, information on a bitmap representing the allocation pattern may be used. This makes it possible to allocate the duplicated packets discretely in the time direction, for example. As a result, it becomes possible to obtain the effect of time diversity.

[0232] In the above (2), the information on the time resource in which the other of the duplicated packets is allocated may be the same as the information on the time resource in which one of the duplicated packets is allocated, which makes it possible to flexibly allocate the time resources of both of the duplicated packets in a communication system, for example.

[0233] As another example, in the above (2), the information on the time resource in which the other of the duplicated packets is allocated may be the time resource excluding the time resource in which one of the packets is allocated among the frequency and / or time resources granted and / or scheduled by the base station. This makes it possible to reduce, for example, the amount of signaling from the base station and / or the upper NW device to the UE. As a result, it is possible to improve the efficiency of the communication system.

[0234] The information in (3) above may include information on the layer in which one of the duplicated packets is located, or may include information on the layer in which the other of the duplicated packets is located, which makes it possible to obtain, for example, a spatial diversity effect in transmitting and receiving the duplicated packets.

[0235] The information (4) above may include information about a code applied to one of the duplicated packets, or may include information about a code applied to the other packet. The code may be, for example, an orthogonal code (e.g., a Hadamard code, a ZC (Zadoff-Chu) code), or may be a code different from the orthogonal code. This makes it possible to perform packet duplication even when, for example, a single carrier and a single layer are used. As a result, it is possible to improve reliability.

[0236] The information (5) above may include, for example, information (e.g., symbol number) on the timing when the frequency resource allocation (1) above is started, information (e.g., number of symbols) on the duration of the frequency resource allocation, or information (e.g., symbol number) on the timing when the frequency resource allocation is terminated. A plurality of pieces of the information above may be provided. For example, when the frequency resource allocation is performed a plurality of times in time resources that are granted and / or assigned for scheduling by the base station, the information above may be provided for the plurality of times. This, for example, can improve the flexibility in scheduling, and can obtain time and frequency diversity effects in transmitting and receiving duplicated packets.

[0237] In the notification of the information shown in (1) to (5) above, NAS signaling or RRC signaling may be used. This allows, for example, a host network device and / or a base station to notify a UE of a lot of information. As a result, the flexibility of the communication system can be improved.

[0238] As another example of the notification, MAC signaling may be used, which allows the base station to quickly notify the UE while enabling more information to be transmitted by multi-level modulation, for example.

[0239] As another example of the notification, L1 / L2 signaling may be used. For example, the information shown in (1) to (5) above may be included in DCI that notifies the grant and / or scheduling assignment, or may be included in a different DCI. This allows, for example, the base station to more quickly notify the UE.

[0240] As another example of using L1 / L2 signaling for the notification, a DCI may be provided for each replicated packet. For example, a grant and / or a scheduling allocation may be provided for each replicated packet. The grant and / or the scheduling allocation for each replicated packet may be included in each DCI and notified. This may, for example, allow for increased flexibility in scheduling while avoiding complexity in designing a communication system.

[0241] The signaling used for the notification may be a combination of the above-mentioned signaling. For example, MAC signaling may be used for notification of information regarding the start and / or end of packet duplication using the same carrier, and L1 / L2 signaling may be used for notification of the information shown in (1) to (5) above. This allows, for example, rapid notification while ensuring the amount of information that can be notified from the base station to the UE.

[0242] In packet duplication using the same carrier, a configured grant and / or a configured scheduling allocation may be used. In the case where a configured grant and / or a configured scheduling allocation is used, the configuration from the base station to the UE may be the same as that disclosed above. For example, the configuration may be included in the configuration of the configured grant and / or the configured scheduling allocation from the base station to the UE, or may be notified using different signaling. This can avoid design complexity regarding reservation of frequency and / or time resources in packet duplication using the same carrier, for example.

[0243] Each of the two duplicated packets may be mapped to a different frequency resource and transmitted. Each transport block used for transmitting and receiving each packet may be mapped to a different frequency resource and transmitted. The two duplicated packets may be assigned to the same time resource assigned by scheduling. This, for example, provides a frequency diversity effect in packet duplication. In addition, the transmitting device can transmit both duplicated packets simultaneously, which can reduce, for example, latency fluctuations, i.e., jitter, caused by HARQ retransmission of packets.

[0244] The frequency resources may be arranged in a concentrated manner. The frequency resources used for transmitting the packets may be adjacent to each other or may be separated from each other. The frequency resources may be set in units of RB or in units of multiple RBs, for example.

[0245] The base station may inform the UE of information of the packets mapped to each frequency resource. The UE may use the information to map the duplicated packets to each frequency resource and transmit them to the base station. Alternatively, the UE may use the information to extract each duplicated packet from the signal received in each frequency resource.

[0246] Fig. 18 shows an operation of transmitting and receiving duplicated packets on the same carrier. In the example shown in Fig. 18, frequency and time resources notified as a grant from the base station to the UE are indicated by thick dashed lines. Fig. 18 shows an example in which one of the duplicated packets is mapped to transport block #1, and the other packet is mapped to transport block #2. Fig. 18 shows a case in which the frequency resources to which the duplicated packets are mapped are arranged in a concentrated manner and adjacent to each other. In Fig. 18, the period during which data is transmitted from the transmitting side device is indicated as Cycle Time. In Fig. 18, the arrangement of control channels and / or reference signals, etc. is omitted.

[0247] 18, a physical channel signal generated by transport block #1 is mapped to a high-frequency half 1802 of time and frequency resource 1801 granted or allocated by a base station. A physical channel signal generated by transport block #2 is mapped to a low-frequency half 1803 of resource 1801.

[0248] In Fig. 18, a resource 1804, an area 1805, and an area 1806 are similar to the resource 1801, the area 1802, and the area 1803, respectively. In Fig. 18, a resource 1807, an area 1808, and an area 1809 are similar to the resource 1801, the area 1802, and the area 1803, respectively.

[0249] FIG. 18 shows an example in which a signal of a physical channel generated by transport block #1 is mapped to regions 1802, 1805, and 1808, and a signal of a physical channel generated by transport block #2 is mapped to regions 1803, 1806, and 1809. However, the mapping regions may be interchanged between transport block #1 and transport block #2. For example, transport block #1 may be mapped to regions 1803, 1806, and 1809, and transport block #2 may be mapped to regions 1802, 1805, and 1808. The above mapping may be switched every time. For example, transport block #1 may be mapped to regions 1802, 1806, and 1808, and transport block #2 may be mapped to regions 1803, 1805, and 1809. This allows, for example, a base station to flexibly perform scheduling.

[0250] FIG. 18 shows a case where the region to which transport block #1 is mapped is adjacent to the region to which transport block #2 is mapped. However, these regions may be separated. For example, regions 1802 and 1803 may be separated from each other in the frequency direction. The same may be true for regions 1805 and 1806, and regions 1808 and 1809. In the above case, resource 1801 may be allocated discretely. The same may be true for resources 1804 and 1807. This allows, for example, the base station to allocate other channels between the two separated regions, thereby improving flexibility in scheduling.

[0251] As another example, each frequency resource may be discretely arranged. The frequency resource may be arranged in units of RB, in units of a plurality of RBs, or in units of subcarriers. The frequency resources used for transmitting each packet may be adjacent to each other, or may be separated from each other. This, for example, provides a frequency diversity effect in transmitting and receiving each duplicated packet, and as a result, the reliability of communication can be improved.

[0252] FIG. 19 shows another example in which duplicated packets are transmitted and received on the same carrier. In FIG. 19, frequency and time resources notified as a grant from the base station to the UE are indicated by thick dashed lines. FIG. 19 shows an example in which one of the duplicated packets is mapped to transport block #1, and the other packet is mapped to transport block #2. FIG. 19 shows a case in which the frequency resources to which the duplicated packets are mapped are arranged discretely and adjacent to each other. In FIG. 19, the period in which data is transmitted from the transmitting side device is indicated as Cycle Time. In FIG. 19, the arrangement of control channels and / or reference signals, etc. is omitted. In FIG. 19, the same elements as in FIG. 18 are assigned the same numbers, and common explanations are omitted.

[0253] 19, of time and frequency resources 1801 granted or allocated by the base station, a physical channel signal generated by transport block #1 is mapped to a time and frequency region 1902 indicated by a downward-slanting line from left to right. Of resources 1801, a physical channel signal generated by transport block #2 is mapped to a time and frequency region 1903 indicated by a downward-slanting line from right to left.

[0254] In Fig. 19, a resource 1804, an area 1905, and an area 1906 are similar to the resource 1801, the area 1902, and the area 1903, respectively. In Fig. 19, a resource 1807, an area 1908, and an area 1909 are similar to the resource 1801, the area 1902, and the area 1903, respectively.

[0255] In Fig. 19, as in Fig. 18, the area in which the signal of the physical channel generated by transport block #1 is mapped may be replaced with the area in which the signal of the physical channel generated by transport block #2 is mapped. The above mapping may be switched over time. This allows, for example, the base station to flexibly perform scheduling.

[0256] In Fig. 19, the region to which transport block #1 is mapped may be separate from the region to which transport block #2 is mapped, as in Fig. 18. In the above case, resources 1801, 1804, and 1807 may be allocated discretely. This allows, for example, the base station to allocate other channels between the two separate regions, thereby improving flexibility in scheduling.

[0257] As another example, frequency resources used for transmitting one packet may be arranged in a concentrated manner, and frequency resources used for transmitting the other packet may be arranged in a distributed manner. One frequency resource may be arranged between the distributedly arranged frequency resources of the other packet. This allows, for example, a base station to flexibly perform scheduling in the frequency direction.

[0258] Another method for mapping the duplicated packets is disclosed. Each of the duplicated packets may be mapped to a different time resource and transmitted. For example, each of the duplicated packets may be mapped to a different symbol. Each transport block used for transmitting and receiving each packet may be mapped to a different time resource (for example, a symbol) and transmitted. Both of the duplicated packets may be allocated within the same time resource allocated by scheduling. This, for example, provides a time diversity effect in packet duplication. In addition, the transmitting side device can transmit both of the duplicated packets within the same scheduling resource, and as a result, for example, it is possible to reduce latency fluctuation, i.e., jitter, caused by HARQ retransmission of packets.

[0259] Each time resource may be arranged in a centralized manner or in a distributed manner. The time resource may be set, for example, in units of symbols, in units of minislots, or in other units. For example, the time resource may be arranged in a centralized manner, thereby reducing the amount of processing in the communication system. As another example, the time resource may be arranged in a distributed manner, thereby improving the time diversity effect.

[0260] The base station may inform the UE of information of packets mapped to each time resource. The UE may use the information to map duplicated packets to each time resource and transmit them to the base station. Alternatively, the UE may use the information to extract each duplicated packet from a signal received in each time resource.

[0261] Fig. 20 shows another example in which duplicated packets are transmitted and received on the same carrier. In Fig. 20, the frequency and time resource notified as a grant from the base station to the UE are indicated by a thick dashed line. Fig. 20 shows an example in which one of the duplicated packets is mapped to transport block #1, and the other packet is mapped to transport block #2. Fig. 20 shows a case in which the time resources to which the duplicated packets are mapped are centrally arranged. In Fig. 20, the period in which data is transmitted from the transmitting side device is indicated as Cycle Time. In Fig. 20, the arrangement of control channels and / or reference signals, etc. is omitted. In Fig. 20, the same elements as in Fig. 18 are assigned the same numbers, and common explanations are omitted.

[0262] 20, of time and frequency resources 1801 granted or allocated by the base station, a physical channel signal generated by transport block #1 is mapped to a time and frequency region 2002 indicated by a downward slanting line to the left. Of resources 1801, a physical channel signal generated by transport block #2 is mapped to a time and frequency region 2003 indicated by a downward slanting line to the right.

[0263] In Fig. 20, a resource 1804, an area 2005, and an area 2006 are similar to the resource 1801, the area 2002, and the area 2003, respectively. In Fig. 20, a resource 1807, an area 2008, and an area 2009 are similar to the resource 1801, the area 2002, and the area 2003, respectively.

[0264] In Fig. 20, as in Fig. 18, the area in which the signal of the physical channel generated by transport block #1 is mapped may be replaced with the area in which the signal of the physical channel generated by transport block #2 is mapped. The above mapping may be switched over time. This allows, for example, the base station to flexibly perform scheduling.

[0265] In FIG. 20, the case where the time resources to which the duplicated packets are mapped are arranged in a concentrated manner is shown. However, these time resources may be arranged in a distributed manner. For example, the packets to be mapped may be replaced for each symbol. This makes it possible to improve the time diversity effect in the transmission of both packets, for example.

[0266] In the above example, both packets are allocated in the same scheduling resource when the duplicated packets are mapped to different time resources. However, both packets may be allocated in different scheduling resources. This can avoid design complexity related to scheduling in, for example, a communication system.

[0267] Another method for mapping the duplicated packets is disclosed. Each of the duplicated packets may be mapped to different time and frequency resources and transmitted. For example, in a certain time resource (e.g., a symbol), each of the duplicated packets may be mapped to different frequency resources, and in another time resource, the frequency resources to which each packet is assigned may be switched. Both of the duplicated packets may be assigned within the same time resource assigned by scheduling. This, for example, provides frequency diversity effects and time diversity effects in packet duplication, and as a result, the reliability of communication can be improved. In addition, the transmitting device can transmit both of the duplicated packets within the same scheduling resource, and as a result, for example, the fluctuation in latency caused by HARQ retransmission of packets, i.e., jitter, can be reduced.

[0268] In each time resource, the frequency resources allocated to each packet may be arranged in a centralized manner or in a distributed manner. For example, the centralized arrangement can reduce the amount of processing in the communication system. As another example, the distributed arrangement can improve the frequency diversity effect.

[0269] In each frequency resource, the time resources allocated to each packet may be arranged in a concentrated manner or in a distributed manner. For example, the time resources may be arranged in a concentrated manner to reduce the amount of processing in the communication system. As another example, the time diversity effect may be improved by arranging the time resources in a distributed manner.

[0270] The base station may inform the UE of information of packets mapped to each time and frequency resource. The UE may use the information to map the replicated packets to the frequency resource in the time resource and transmit the replicated packets to the base station. Alternatively, the UE may use the information to extract each replicated packet from the signal received in the time resource.

[0271] Fig. 21 shows another example in which duplicated packets are transmitted and received on the same carrier. In Fig. 21, the frequency and time resources notified as a grant from the base station to the UE are indicated by thick dashed lines. Fig. 21 shows an example in which one of the duplicated packets is mapped to transport block #1, and the other packet is mapped to transport block #2. Fig. 21 shows a case in which the frequency resources to which the duplicated packets are mapped are concentratedly arranged in each time resource. In Fig. 21, the cycle in which data is transmitted from the transmitting side device is indicated as Cycle Time. In Fig. 21, the arrangement of control channels and / or reference signals, etc. is omitted. In Fig. 21, the same elements as in Fig. 18 are assigned the same numbers, and common explanations are omitted.

[0272] In Fig. 21, of time and frequency resources 1801 granted or allocated by the base station, a physical channel signal generated by transport block #1 is mapped to a time and frequency region 2102 indicated by diagonal lines downward to the left. Of resources 1801, a physical channel signal generated by transport block #2 is mapped to a time and frequency region 2103 indicated by diagonal lines downward to the right. In the example shown in Fig. 21, the frequency resources mapped to transport block #1 and the resources mapped to transport block #2 are switched between the first half and the second half of the time resources granted or allocated in scheduling.

[0273] In Fig. 21, a resource 1804, an area 2105, and an area 2106 are similar to the resource 1801, the area 2102, and the area 2103, respectively. In Fig. 21, a resource 1807, an area 2108, and an area 2109 are similar to the resource 1801, the area 2102, and the area 2103, respectively.

[0274] In Fig. 21, as in Fig. 18, the area in which the signal of the physical channel generated by transport block #1 is mapped may be replaced with the area in which the signal of the physical channel generated by transport block #2 is mapped. The above-mentioned replacement of mapping may be performed for each schedule allocation. This allows, for example, the base station to flexibly perform scheduling.

[0275] In FIG. 21, the case where the time resources to which the duplicated packets are mapped in a certain frequency resource are arranged in a concentrated manner is shown. However, these time resources may be arranged in a distributed manner. For example, the packets to be mapped may be replaced for each symbol. This makes it possible to improve the time diversity effect in the transmission of both packets, for example.

[0276] In the above example, both packets are allocated in the same scheduling resource when the duplicated packets are mapped to different time resources. However, both packets may be allocated in different scheduling resources. This can avoid design complexity related to scheduling in, for example, a communication system.

[0277] Another method for mapping the duplicated packets is disclosed. The duplicated packets may be spatially multiplexed on different layers and transmitted. The duplicated packets may be spatially multiplexed using different codebooks and transmitted. The transport blocks used for transmitting and receiving each packet may be spatially multiplexed on different layers and transmitted, or may be spatially multiplexed using different codebooks and transmitted. This eliminates the need to allocate frequency and / or time resources to each packet, and as a result, it is possible to avoid the complexity of the design in the communication system. In addition, the transmitting side device can simultaneously transmit both duplicated packets, and as a result, it is possible to reduce the fluctuation in latency, i.e., jitter, caused by, for example, HARQ retransmission of packets.

[0278] The base station may notify the UE of information on the layer to which each packet is mapped, or may notify the UE of information on the codebook used for each packet. The UE may use the information to map the duplicated packets to each layer and transmit them to the base station. Alternatively, the UE may use the information to extract each duplicated packet from a signal received from the base station. As another example, the UE may perform modulation processing on the duplicated packets, or may extract each duplicated packet from a signal received from the base station, using information on the codebook notified from the base station.

[0279] Another method for mapping the duplicated packets is disclosed. Both duplicated packets may be code-multiplexed and transmitted. The code used for the code-multiplexing may be, for example, an orthogonal code (e.g., Hadamard code, ZC (Zadoff-Chu) code), or may be a code different from the orthogonal code. This makes it possible to perform packet duplication even when, for example, a single carrier and a single layer are used. As a result, it is possible to improve reliability.

[0280] Another method for mapping duplicated packets is disclosed. For example, in a certain time resource (e.g., a symbol), each of the two packets may be mapped to a different frequency resource, and in another time resource, the frequency resource to which each packet is assigned may be switched. The duplicated packets may be assigned within the same time resource assigned by scheduling. This, for example, provides a frequency diversity effect and a time diversity effect in packet duplication, and as a result, the reliability of communication can be improved. In addition, the transmitting device can transmit the duplicated packets within the same scheduling resource, and as a result, for example, the fluctuation in latency caused by HARQ retransmission of packets, i.e., jitter, can be reduced.

[0281] The method disclosed in the present modified example 1 of the first embodiment may be combined with the method disclosed in the first embodiment. For example, a plurality of configured grants and / or a plurality of configured scheduling allocations may be performed in the same carrier. Each packet copied in the packet duplication may be mapped to a different configured grant and / or a different configured scheduling allocation in the same carrier and transmitted. This, for example, enables the complexity of the design in the communication system and improves the reliability in the communication using a single carrier.

[0282] The method disclosed in the present modified example 1 of the first embodiment may be used in communication without jitter requirements. For example, in communication without jitter requirements, packet duplication using the same carrier may be performed. This makes it possible to improve reliability even in communication using a single carrier, for example.

[0283] According to this first modification of the first embodiment, it is possible to improve the jitter characteristics even in communications using a single carrier.

[0284] Variation 2 of embodiment 1 In the first embodiment and the first modification of the first embodiment, the case where packet duplication is used as an example of a method for satisfying the requirements of URLLC has been disclosed, but repetition may also be used.

[0285] However, in repetition, the receiving device transmits HARQ feedback after a predetermined number of repetitions. As a result, even if the receiving device receives data during the predetermined number of repetitions and correctly demodulates and decodes the data, the receiving device waits for the remaining number of repetitions before transmitting HARQ feedback. The same applies to the transfer of the received data to a higher layer (e.g., RLC) in the receiving device. As a result, a problem occurs in which the latency in transmitting the data worsens.

[0286] Solutions to the aforementioned problems are disclosed below.

[0287] The receiving device transmits a HARQ-ACK after correctly decoding data in a repetitive transmission. The receiving device may transmit a HARQ-ACK to the transmitting device in the middle of a predetermined number of repetitions. This allows, for example, the receiving device to quickly notify the transmitting device of the HARQ-ACK.

[0288] In a transmission in which repetition is performed, the receiving device may transfer data to a higher layer (e.g., RLC) after the data has been correctly decoded. The transfer may be performed, for example, in the middle of a predetermined number of repetitions. This makes it possible to reduce latency while ensuring reliability in communication using repetition. In the above, the receiving device may transmit a HARQ-ACK to the transmitting device in the middle of a predetermined number of repetitions. This makes it possible, for example, for the receiving device to quickly notify the transmitting device of a HARQ response. As another example of the above, the receiving device may transmit a HARQ-ACK after a predetermined number of repetitions have ended. This makes it possible, for example, to reduce frequency and / or time resources reserved for HARQ-ACK transmission. As a result, it is possible to improve efficiency in the communication system.

[0289] The receiving device may not receive repetitions of data after the data has been decoded as OK, which may reduce power consumption in the receiving device, for example.

[0290] The transmitting device may not repeat the data after receiving the HARQ-ACK, which may reduce the power consumption of the transmitting device and reduce the time and / or frequency resources used for repeating the data.

[0291] The candidates for the transmission timing of the HARQ-ACK may be predefined by a standard. For example, the timing of each of a predetermined number of repetitions may be defined as a candidate for the HARQ-ACK transmission timing. Alternatively, the timing of every multiple times (for example, every two times) in the predetermined number of repetitions may be defined as a candidate for the HARQ-ACK transmission timing. The base station may secure frequency and time resources at the candidate timings for the HARQ-ACK transmission. The base station may notify the UE of the frequency and time resources. The notification may include information on the number of repetitions, or may include information on uplink and / or downlink communication. The UE may transmit the HARQ-ACK to the base station or receive the HARQ-ACK transmitted from the base station in the frequency and time resources included in the notification. If the base station cannot secure the resources, the receiving device may not transmit the HARQ-ACK.

[0292] As another example of determining candidates for the transmission timing of the HARQ-ACK, the base station may determine the candidates and notify the UE. The candidates for the timing determined by the base station may be the same as the timing candidates defined in the standard described above, or may be determined by other methods. The base station may notify the UE of the frequency and time resources. The notification may include information on the number of repetitions described above, information on uplink and / or downlink communication, information on the logical channel to which the HARQ-ACK response is applied, or information on the sequence used in the response (e.g., cyclic shift). The base station may reserve the frequency and / or time resources used in the HARQ-ACK response in advance. The UE may transmit a HARQ-ACK to the base station or receive a HARQ-ACK transmitted from the base station in the frequency and time resources included in the notification. If the base station cannot reserve the resources, the receiving device may not transmit a HARQ-ACK. This enables, for example, flexible scheduling in a communication system.

[0293] As another example of the candidates for the transmission timing of the HARQ-ACK, the timing of each time after a predetermined number of waiting times in a predetermined number of repetitions may be determined as a candidate for the transmission timing of the HARQ-ACK. Alternatively, the timing of each of a plurality of times (e.g., twice) after the predetermined number of waiting times (e.g., the fourth time onward) may be determined as a candidate for the transmission timing of the HARQ-ACK. The predetermined number of waiting times may be, for example, a number of times that results in timely transmission and reception in periodic communication for which a jitter requirement is defined. Timely transmission and reception may be transmission and reception performed at a timing that results in a predetermined latency, i.e., that does not cause jitter (hereinafter, the same may be applied). This makes it possible to reduce, for example, the variation in the transfer timing to a higher layer in a receiving device and / or the transmission timing of the HARQ-ACK. As a result, it is possible to reduce the jitter in the communication between the base station and the UE. The above-mentioned candidates may be defined by a standard, or may be determined by the base station and notified to the UE.

[0294] The base station may determine a timely transmission / reception timing. The base station may notify the UE of information on the timely transmission / reception timing. For the notification, RRC signaling, MAC signaling, or L1 / L2 signaling may be used. The information may be, for example, information on an offset with respect to a transmission cycle, or information on a time that is timely in a predetermined transmission cycle. The information may include information on the cycle. The offset information may be given, for example, in milliseconds, in subframes, in slots, or in symbols. The offset information may include information on a subcarrier interval. The information on the time that is timely may be given, for example, as a time in milliseconds, in subframe numbers, in slot numbers, or in symbols. The UE may use the information to derive a timely transmission / reception timing. For example, the UE may add an integer multiple of the cycle to information on a time that is timely in a predetermined transmission cycle, and derive a time that is timely in a transmission cycle from the current one onward. As another example, the base station may inform the UE only of the appropriate transmission and reception times, e.g., when no periodic transmission occurs between the base station and the UE, allowing the UE to derive the appropriate transmission and reception timings, e.g.

[0295] For the base station to notify the UE of appropriate transmission and reception timing, for example, the method of notifying information relating to the predetermined timing in the first embodiment may be used.

[0296] The UE may perform the HARQ response disclosed in this modification 2 for a transport block including a logical channel included in the notification. The UE may not apply the HARQ response disclosed in this modification 2 to a transport block not including the logical channel. This makes it possible to reduce the amount of processing in the UE, for example.

[0297] The timing at which the receiving device transfers the received data to the upper layer may be determined by a standard, as with the HARQ-ACK, or may be determined by the base station and notified to the UE. The notification may include, for example, information similar to the notification regarding the HARQ-ACK response timing candidates. This makes it possible to reduce, for example, the latency in data transmission and reception.

[0298] FIG. 22 is a diagram showing an operation of a receiving device performing HARQ feedback and forwarding to a higher layer in the middle of a predetermined number of repetitions in repetition. FIG. 22 shows an example in which transmission data is repeated four times and transmitted. In FIG. 22, the period in which data is transmitted from the transmitting device is shown as Cycle Time. FIG. 22 shows a case in which the above-mentioned number of waiting times in transmitting HARQ-ACK from the receiving device to the transmitting device is set to 2. In FIG. 22, a case in which an operation of HARQ response and forwarding to a higher layer is applied in the middle of a predetermined number of repetitions in communication requiring a predetermined jitter characteristic (hereinafter, sometimes referred to as jitter-critical) is shown. In FIG. 22, a reception timing that is appropriate in jitter-critical communication is shown by a broken line. In FIG. 22, a case in which the transmitting device is a base station and the receiving device is a UE is shown.

[0299] 22, the receiving device receives the second transmitted data 2501 as an OK decoded result. Since the data 2501 is received after the appropriate reception timing, the receiving device transfers the data 2501 to a higher layer. Using the fact that the reception result of the data 2501 is OK decoded, the receiving device transmits a HARQ-ACK signal 2502 to the transmitting device.

[0300] Regarding data transmission in the second transmission period shown in Fig. 22, the receiving device receives the third transmitted data 2503 as a decoding result OK. Since the data 2503 is received after the appropriate reception timing, the receiving device transfers the data 2503 to a higher layer. Using the fact that the reception result of the data 2503 is decoding OK, the receiving device transmits a HARQ-ACK signal 2504 to the transmitting device.

[0301] For data transmission in the third transmission period shown in Fig. 22, the receiving side device receives data 2505 transmitted for the first time as a decoding result OK. Since data 2505 is received before the timely reception timing, the receiving side device holds data 2505 until the timely reception timing. The receiving side device transfers data 2505 to a higher layer after the timely reception timing has elapsed. In addition, the receiving side device transmits a HARQ-ACK signal 2506 to the transmitting side device using the fact that the reception result of data 2505 is decoding OK. The receiving side device may transmit the HARQ-ACK signal 2506 by waiting for the HARQ-ACK transmission timing for the second data reception.

[0302] 22, the receiving device receives the fourth transmitted data 2507 as an OK decoded result. Since the data 2507 is received after the appropriate reception timing, the receiving device transfers the data 2507 to a higher layer. Using the fact that the reception result of the data 2507 is OK decoded, the receiving device transmits a HARQ-ACK signal 2508 to the transmitting device.

[0303] In FIG. 22, the case is shown where the number of repetitions is four, and the predetermined number of waiting times for transmitting HARQ-ACK is two. However, the various numbers may be other values. For example, when the communication environment between the base station and the UE is poor, the number of repetitions may be set to a value greater than four, and the number of waiting times may be set to a value greater than two. This makes it possible to improve the reliability of communication using repetitions, for example.

[0304] In Fig. 22, a case where the transmitting device is a base station and the receiving device is a UE, i.e., a case of downlink communication, is shown. However, the example of Fig. 22 can be applied even when the transmitting device is a UE and the receiving device is a base station, i.e., uplink communication. As another example, the example of Fig. 22 can be applied even when both the transmitting device and the receiving device are UE, i.e., sidelink communication. This makes it possible to improve jitter characteristics, for example, not only in downlink communication but also in uplink communication and / or sidelink communication.

[0305] In FIG. 22, the receiving device transmits the HARQ-ACK as the HARQ-ACK for reception after a predetermined number of waiting times. However, the receiving device may transmit the HARQ-ACK when decoding is OK. This allows, for example, the HARQ-ACK transmission resource after decoding is OK to be used for transmitting other signals. As a result, the efficiency of the communication system can be improved.

[0306] HARQ feedback may not be performed. For example, the receiving device may not perform HARQ feedback to the transmitting device. The transmitting device may consider that all transmitted data has been decoded successfully in the receiving device. The operation of not performing HARQ feedback may be applied, for example, when repetition is performed. This makes it possible to reduce the amount of signaling between the base station and the UE, and to reduce the amount of processing in the HARQ process of the receiving device. In addition, this makes it unnecessary for the base station to secure frequency and time resources used for HARQ feedback, and as a result, it is possible to improve the utilization efficiency of frequency and time resources in the communication system.

[0307] As another example of the HARQ feedback, only the HARQ-NACK may be fed back. For example, the receiving device may transmit only the HARQ-NACK to the transmitting device, or may not transmit the HARQ-ACK. The transmitting device may consider that all data without HARQ feedback has been decoded successfully in the receiving device. The operation of feeding back only the HARQ-NACK may be applied, for example, when repetition is being performed. This makes it possible to reduce, for example, the amount of signaling between the base station and the UE, and to reduce the amount of processing in the HARQ process of the receiving device. This also makes it possible to improve the reliability of communication between the base station and the UE.

[0308] The HARQ feedback operation from the receiving device to the transmitting device may be predefined by a standard. The feedback operation may be defined for each communication method. For example, in repetition communication, HARQ feedback may be performed only for HARQ-NACK. Also, HARQ feedback may be performed in packet duplication.

[0309] As another example, the HARQ feedback operation from the receiving device to the transmitting device may be determined by the base station and notified to the UE. The base station may determine the feedback operation for each communication method. For example, in repetition communication, HARQ feedback may be performed only for HARQ-NACK. Also, HARQ feedback may be performed in packet duplication. As another example, the base station may determine the feedback operation using the communication status (e.g., QoS) between the base station and the UE, or may determine the feedback operation using information on network slicing. For example, when the SINR is good, HARQ feedback may not be performed. Also, when the SINR is poor, only HARQ-NACK may be fed back. This allows, for example, efficiency in the communication system to be improved.

[0310] In the notification from the base station to the UE, RRC signaling may be used. This allows, for example, an increase in the amount of information in the notification. As another example, MAC signaling may be used in the notification. This allows, for example, rapid notification while ensuring reliability by HARQ retransmission. As another example, L1 / L2 signaling may be used. This allows, for example, rapid operation decision and rapid notification taking into account the communication situation between the base station and the UE.

[0311] As another example, the HARQ feedback operation from the receiving device to the transmitting device may be determined by an upper NW device and notified to the UE. The upper NW device may be, for example, an AMF or an SMF. The upper NW device may determine the feedback operation using, for example, a QoS requirement in communication with the UE, or may determine the feedback operation using information on network slicing. The notification may be performed via a base station. In the notification, for example, NAS signaling may be used. This makes it possible to perform communication between the base station and the UE in accordance with the QoS requirement.

[0312] According to the present modification 2 of the first embodiment, it is possible to reduce latency while ensuring reliability in communication using repetition, and also to reduce jitter.

[0313] Variation 3 of embodiment 1 In adjusting the contention between data transmission in a communication that requires a certain jitter characteristic (hereinafter, sometimes referred to as jitter-critical) and data transmission in another communication, the UE may use LCP (Logical Channel Prioritization) in MAC (see Non-Patent Document 17). The above-mentioned operation may be applied in uplink communication.

[0314] However, in the LCP, a parameter indicating priority is given semi-statically (see Non-Patent Document 26 (3GPP TS38.331 V15.2.1)). For this reason, for example, when data of other logical channels with higher priority exists, the UE allocates data to the logical channel with higher priority before the jitter-critical logical channel. This may result in a case where data cannot be allocated to the jitter-critical logical channel, resulting in a problem of deterioration of jitter characteristics.

[0315] Solutions to the aforementioned problems are disclosed below.

[0316] The UE may allocate jitter-critical logical channels with priority, for example, in an LCP in a MAC layer of the UE, jitter-critical logical channels may be allocated with priority over non-jitter-critical logical channels.

[0317] As an example of the preferential allocation in LCP, the UE may allocate jitter-critical logical channels in order of priority, and allocate the jitter-critical logical channels in the remaining allocatable data size in order of priority. The base station may notify the UE of information indicating whether the communication is jitter-critical. The information may be included in the logical channel configuration in the RRC configuration transmitted from the base station to the UE. The UE may use the information to determine whether the configured logical channel is jitter-critical. This allows, for example, the UE to transmit the jitter-critical logical channel with priority, thereby reducing the jitter.

[0318] As another example of the preferential allocation in the LCP, a high priority may be assigned to a jitter-critical logical channel. A value representing the highest priority among the parameters indicating the priority in the LCP may be assigned to the jitter-critical logical channel. Alternatively, any value in the range from the highest priority to a predetermined number may be assigned to the jitter-critical logical channel. In this way, in addition to the above-mentioned effects, for example, the base station does not need to notify the UE of information indicating whether the communication is jitter-critical, and as a result, it is possible to avoid complexity in the communication system.

[0319] Another solution is disclosed. For a jitter-critical logical channel, the UE transfers data of the logical channel to the MAC layer of the UE at an appropriate transmission timing. The UE may hold the data of the jitter-critical logical channel without transferring it to the MAC layer until the appropriate transmission timing. This makes it possible to keep the latency within a certain range in communications that require, for example, deterministic latency, that is, latency between a certain level and a certain level.

[0320] The base station may determine a timely transmission / reception timing. The base station may notify the UE of information on the timely transmission / reception timing. For the notification, RRC signaling, MAC signaling, or L1 / L2 signaling may be used. The information may be, for example, information on an offset with respect to a transmission cycle, or information on a time that is timely in a predetermined transmission cycle. The information may include information on the cycle. The offset information may be given, for example, in milliseconds, in subframes, in slots, or in symbols. The offset information may include information on a subcarrier interval. The information on the time that is timely may be given, for example, as a time in milliseconds, in subframe numbers, in slot numbers, or in symbols. The UE may use the information to derive a timely transmission / reception timing. For example, the UE may add an integer multiple of the cycle to information on a time that is timely in a predetermined transmission cycle, and derive a time that is timely in a transmission cycle from the current one onward. As another example, the base station may inform the UE only of the appropriate transmission and reception times, e.g., when no periodic transmission occurs between the base station and the UE, allowing the UE to derive the appropriate transmission and reception timings, e.g.

[0321] The forwarding or holding operation may be performed in a higher layer (e.g., an application layer or a layer called a service layer), in the SDAP, in the PDCP, or in the RLC.

[0322] As another example, the MAC layer itself may hold the data of the logical channel. For example, in the LCP, the allocation of the jitter-critical logical channel may be performed only at a predetermined timing. The predetermined timing may not include a timing range before the timing of the timely transmission on the logical channel. This makes it possible to prevent the allocation of the jitter-critical logical channel before the timely transmission, and thus improve the jitter characteristics.

[0323] The predetermined timing may be predefined by a standard. For example, the predetermined timing may be the same as the timing in the jitter tolerance range, or may be a part of the timing in the jitter tolerance range (for example, the timing from the right time to the rear end of the jitter tolerance range). The base station may notify the UE of information for deriving the predetermined timing. The information for deriving the predetermined timing may be included in, for example, a QoS parameter, or may be included in a logical channel configuration included in an RRC configuration transmitted from the base station to the UE. The QoS parameter may be the same as the QoS parameter disclosed in the first embodiment. The information for deriving the predetermined timing may be information on the jitter tolerance range, for example. The information on the jitter tolerance range may be given in absolute time (for example, in milliseconds or microseconds), in the number of subframes, or in the number of slots. Alternatively, the information on the jitter tolerance range may be given as information using a data transmission cycle (for example, a cycle time) in the logical channel (for example, a ratio to the data transmission cycle). Alternatively, the information on the jitter tolerance range may be given in another manner. The information for the UE to derive the predetermined timing may include information on a data transmission period, or information on the timing of timely transmission (e.g., information using a slot number, information using a symbol number). This makes it possible to reduce the amount of signaling from the base station to the UE regarding the derivation of the predetermined timing in the UE, for example.

[0324] The predetermined timing may be determined by the base station and signaled to the UE, which allows, for example, flexible scheduling in the communication system.

[0325] The base station may notify the UE of information about the predetermined timing. The information about the timing may be, for example, the same as the information for the UE to derive the predetermined timing described above. For example, the method disclosed in the first embodiment may be used to notify the predetermined timing.

[0326] Another solution is disclosed. In the allocation between multiple jitter-critical logical channels, the allocation may be performed in the order of narrowest jitter tolerance. This makes it possible to allocate to the logical channel with narrowest jitter tolerance and low priority when, for example, a logical channel with wide jitter tolerance and high priority coexists with a logical channel with narrow jitter tolerance and low priority. As a result, it becomes possible to satisfy the jitter characteristics.

[0327] As another example, the UE may assign logical channels in ascending order of time from the timing (e.g., slot, minislot, symbol) to be scheduled to the rear end of the time range in which the jitter tolerance can be satisfied. This allows the jitter characteristics of the logical channels to be satisfied even when multiple jitter-critical logical channels exist at different timings.

[0328] As another example, the base station may assign higher priority to logical channels with lower jitter tolerance, which may, for example, reduce complexity in the design of the communication system.

[0329] As another example, the UE may determine logical channel allocation using the size of data that can be transmitted in each logical channel. The size may be, for example, the size of a transmittable RLC PDU, the size of a PDCP PDU, the size of an SDAP PDP, the size of an SDAP SDU, or the sum of a plurality of the above. The UE may allocate logical channels in descending order of size, for example. This may, for example, reduce data congestion in the communication system.

[0330] The above-mentioned method may be applied to the allocation between the jitter-critical logical channel and the logical channel with the latency requirement. The UE may apply the jitter tolerance of the jitter-critical logical channel by replacing it with the latency requirement. For example, the UE may allocate the logical channel in the order of the shortest time from the timing (e.g., slot, minislot, symbol) to be scheduled to the rear end of the time range in which the latency requirement and / or the jitter tolerance can be satisfied. This makes it possible to satisfy, for example, both the jitter characteristics of the jitter-critical logical channel and the latency requirement of the logical channel with the latency requirement.

[0331] As another example, the base station may set a high priority to logical channels with narrow jitter tolerance and / or latency requirements. For example, the UE may replace the jitter tolerance of a jitter-critical logical channel with a latency requirement. In this replacement, for example, the latency requirement of the jitter-critical logical channel may be the time from the front end to the rear end of the jitter tolerance, or the time from the center to the rear end of the jitter tolerance. This may, for example, avoid complexity in designing a communication system.

[0332] The information on the jitter tolerance and / or latency requirement may be included in the QoS parameters, or may be included in the logical channel configuration included in the RRC configuration transmitted from the base station to the UE. The QoS parameters may be notified from the base station to the UE, or may be notified from the upper NW device to the UE via the base station, or may be notified from the upper NW device to the base station. The QoS parameters may be the same as the QoS parameters disclosed in the first embodiment.

[0333] In a communication system, a latency requirement that is looser than a predetermined threshold may be considered as having no latency requirement. The threshold may be determined in advance by a standard, may be determined by a base station and notified to a UE, or may be determined by an upper NW device and notified to a base station. The base station may or may not notify the UE of the threshold determined by the upper NW device. This makes it possible to avoid, for example, complexity in the communication system.

[0334] The above-mentioned method may be applied to the allocation among multiple logical channels having latency requirements. For example, the UE may allocate logical channels in the order of the time to the latency requirement. The information regarding the latency requirement may be the same as that described above. This makes it possible to satisfy the latency requirement in the multiple logical channels, for example.

[0335] Figure 23 is a diagram showing the operation of LCP when both a jitter-critical logical channel and a logical channel with a latency requirement exist, where LCH#1 is a logical channel with a latency requirement and LCH#2 is a jitter-critical logical channel.

[0336] 23, first, a description will be given of allocation of logical channels to scheduling unit 2801. The tolerable latency in LCH#1 is shorter than the time to the rear end of the jitter tolerance range in LCH#2. Using this, the UE allocates data 2802 of LCH#1 to scheduling unit 2801.

[0337] 23, allocation of logical channels to the next scheduling unit 2803 of the scheduling unit 2081 will be described. There is no data of logical channels with latency requirements and jitter-critical logical channels other than LCH#2. Therefore, the UE allocates data 2804 of LCH#2 to the scheduling unit 2803.

[0338] Another solution is disclosed. The priority may be variable. For example, in jitter-critical communication, the priority may be increased in the jitter tolerance range. For example, the UE may increase the priority in the logical channel by subtracting a predetermined value (hereinafter, sometimes referred to as a priority offset) from the priority value shown in Non-Patent Document 17.

[0339] The subtracted priority value may not be less than a predetermined threshold. When the subtracted priority value is less than the predetermined threshold, the UE may set the subtracted priority value to the same value as the predetermined threshold. The predetermined threshold may be determined by a standard, or may be determined by the base station and notified to the UE. This makes it possible to prevent, for example, the subtracted priority value from falling outside the range defined by the standard. As a result, it is possible to prevent malfunctions in the LCP. As another example, it is possible to prevent the priority from being excessively high in the priority offset.

[0340] The priority offset may be a uniform value within the jitter tolerance, which may avoid design complexities in, for example, the LCP.

[0341] As another example, the priority offset may be variable within the jitter tolerance range. For example, within the jitter tolerance range, the priority offset after the timely reception timing may be set to a higher value than the priority offset before the timely reception timing. This allows, for example, even when a HARQ retransmission occurs, the retransmission to be transmitted with priority, and as a result, the jitter characteristics can be improved.

[0342] A priority offset may be given for each scheduling unit of time. For example, within the jitter tolerance range, the later the time, the higher the priority offset may be set. This, for example, in addition to the above-mentioned effects, makes it possible to flexibly perform logical channel allocation in LCP. The scheduling unit of time may be a subframe, a slot, a minislot, or a symbol.

[0343] The priority offset may be predefined by a standard. For example, a uniform offset amount may be defined. Alternatively, an offset amount for each scheduling timing may be defined. Alternatively, a correspondence between a timing range and an offset amount may be defined. As an example of a correspondence between a timing range and an offset amount, a range from the front end to the rear end of a jitter tolerance range may be divided, and an offset amount may be defined for each divided range. For example, an offset amount in a range from the front end to the center of a jitter tolerance range and an offset amount in a range from the center to the rear end of a jitter tolerance range may be defined.

[0344] The logical channels to which the priority offset is applied may be predefined in the standard. For example, the priority offset may be applied to a jitter-critical logical channel and / or a logical channel having a latency requirement below a predefined threshold. This allows, for example, the logical channel to be given a higher priority than other logical channels, so that the jitter and / or latency requirements can be met.

[0345] As another example, the base station may determine the priority offset and notify the UE. For example, RRC signaling may be used for the notification. The notification may include information on the logical channel. The information may include information on the offset amount. The UE may apply the offset included in the notification to the logical channel included in the notification. The information on the offset amount may be the same as the offset amount predetermined by the standard. This allows the base station to notify the UE of a lot of information, for example, and therefore improves the flexibility in setting the priority offset.

[0346] As another example of the notification, MAC signaling may be used. The notification may include information on a logical channel or may include information on an offset. The information on the offset may be information similar to an offset amount predetermined in a standard. The UE may apply the offset included in the notification to the logical channel included in the notification. This allows the UE to quickly apply the offset, for example.

[0347] As another example of the notification, L1 / L2 signaling may be used. The notification may include information about a logical channel or may include information about an offset. The notification may be included in a DCI including a scheduling grant, or may be included in a different DCI. The notification may also be a different L1 / L2 signaling. The information about the offset may be the same as an offset amount predefined in a standard, or may be an offset amount applied in the grant. This allows, for example, the UE to apply the offset more quickly.

[0348] A plurality of pieces of information regarding the offset amount may be provided. The plurality of pieces of information may be defined by a standard, may be determined by a base station and notified to the UE, or may be determined by an upper NW device and notified to the UE via the base station. The base station may notify the UE of an identifier of the information to be used among the plurality of pieces of information. The identifier may be notified by RRC signaling, MAC signaling, or L1 / L2 signaling. The notification may include information regarding a logical channel to which the offset is applied. The UE may derive the information to be used by using the identifier. When determining the information to be used, the base station may use a setting from an upper NW device, for example, a QoS parameter, or may use information regarding network slicing. This makes it possible to reduce the amount of signaling from the base station to the UE, for example.

[0349] Fig. 24 is a diagram showing the assignment of priority offsets to jitter-critical logical channels. Fig. 24 shows a case where a priority offset is set for each time that is a scheduling unit within a jitter tolerance range. In Fig. 24, no priority offset is assigned outside the jitter tolerance range.

[0350] In Fig. 24, the priority offset is set to increase monotonically from the scheduling timing that is the front end of the jitter tolerance range to the timing that is timely. In Fig. 24, a uniform value is set as the priority offset from the scheduling timing that is the rear end of the jitter tolerance range to the timing that is timely.

[0351] In Fig. 24, the case where the priority offset is set for each time that is a scheduling unit is shown. However, a uniform value may be set as the priority offset within the jitter tolerance range. This makes it possible to avoid, for example, design complexity in the LCP processing of the UE.

[0352] Even outside the jitter tolerance range, an offset may be applied to the priority. For example, the priority may be lowered outside the jitter tolerance range. This makes it possible to reduce the possibility that the logical channel is assigned outside the jitter tolerance range, and as a result, it is possible to improve the jitter characteristics.

[0353] As another example, the priority may be lowered before the front end of the jitter tolerance range and raised after the rear end. A monotonically decreasing priority offset may be given in the range from just after the rear end of the jitter tolerance range to just before the front end of the jitter tolerance range in the next transmission period. This makes it possible to prevent data retention in the logical channel while improving jitter characteristics.

[0354] 25 is a diagram showing another example of priority offset assignment in a jitter-critical logical channel. In FIG. 25, the priority offset within the jitter tolerance range is the same as in FIG.

[0355] In Fig. 25, a priority offset is also applied outside the jitter tolerance range. The priority offset outside the jitter tolerance range is an offset in the direction of lowering the priority. In Fig. 25, a uniform value is set as the priority offset outside the jitter tolerance range.

[0356] In Fig. 25, a uniform value may be set as the priority offset within the jitter tolerance range, similarly to Fig. 24. This makes it possible to avoid design complexity in the processing of the LCP of the UE, for example.

[0357] In FIG. 25, the case where the priority offset outside the jitter tolerance range is a uniform value is shown. However, the offset may be variable for each scheduling unit. For example, the priority may be lowered before the front end of the jitter tolerance range and raised after the rear end. The priority offset may be given in a monotonically decreasing manner in the range from just after the rear end of the jitter tolerance range to just before the front end of the jitter tolerance range in the next transmission period. This makes it possible to prevent data retention in the logical channel while improving the jitter characteristics.

[0358] The offset of the priority may be applied to a logical channel having a latency requirement. The method of setting the offset amount in a logical channel having a latency requirement and the method of notifying the setting may be the same as the offset in a jitter-critical logical channel. As an example of the correspondence between the timing range and the offset amount, the range from the data generation time to the rear end transmission timing that satisfies the latency requirement may be divided, and an offset amount may be determined for each divided range. This makes it possible to communicate with a logical channel having a latency requirement while satisfying the latency requirement.

[0359] Fig. 26 shows how to assign a priority offset to a logical channel with a latency requirement. Fig. 26 shows how to set a priority offset for each scheduling unit within the latency tolerance range. In Fig. 26, the starting time of the latency tolerance range is the upstream data generation time.

[0360] In the example shown in Fig. 26, the priority offset is set to increase over time in the section from the scheduling timing at the time of data generation to the scheduling timing three before the end of the latency tolerance range. In Fig. 26, a uniform value is set as the priority offset from the scheduling timing three before the end of the latency tolerance range to the end of the latency tolerance range. In Fig. 26, no priority offset is applied outside the latency tolerance range.

[0361] In FIG. 26, a case where the priority offset is set for each time that is a scheduling unit is shown. However, a uniform value may be set as the priority offset within the latency tolerance range. This makes it possible to avoid design complexity in the processing of the LCP of the UE, for example.

[0362] In FIG. 26, an example is shown in which the priority offset is set only within the latency tolerance range. However, the priority offset may be set beyond the latency tolerance range. This allows the UE to quickly transmit data to the base station even beyond the latency tolerance range, and as a result, it is possible to prevent data from being accumulated in the UE.

[0363] A priority offset may be applied to the scheduling using the set grant. The method of applying the priority offset in the set grant may be the same as the method disclosed in the present modification 3 of the first embodiment. This makes it possible to satisfy the jitter characteristics, for example, even in the scheduling using the set grant.

[0364] A jitter-critical logical channel may be switched to a non-jitter-critical logical channel, and a non-jitter-critical logical channel may be switched to a jitter-critical logical channel.

[0365] The base station may determine the switching, and may notify the UE of information regarding the switching. For the notification, for example, RRC signaling, MAC signaling, or L1 / L2 signaling may be used.

[0366] As another example, the decision to switch may be made by an upper NW device. The upper NW device may notify the UE of information regarding the switch. For example, NAS signaling may be used for the notification. The notification of the switch may be made via a base station.

[0367] As another example, the decision to switch may be made by the UE. The UE may notify the base station or the upper NW device of information related to the switch. The base station or the upper NW device may make the decision regarding the switch. The base station and / or the upper NW device may notify the UE of information related to the decision.

[0368] The notification of the switch may include information about the logical channel, or may include information about the QoS after the switch, such as information about jitter characteristics or information about latency requirements.

[0369] According to the third modification of the first embodiment, it is possible to improve the jitter characteristics even when both jitter-critical communication and other communications exist.

[0370] Variation 4 of embodiment 1 In jitter-critical communications, data that falls outside of the jitter tolerance range may be discarded. This may be done in upstream communications or downstream communications, as well as in communications with latency requirements.

[0371] In the discarding, a threshold different from the jitter tolerance range may be used. For example, a range wider than the jitter tolerance range may be set. Data outside the wide range may be discarded. The same may be true for communications with latency requirements.

[0372] The discarding operation may be performed in the transmitting device. The discarding operation may be performed by the application layer, the SDAP layer, or the PDCP layer of the transmitting device. When the PDCP layer performs the discarding operation, the PDCP SDU may be discarded. For example, the PDCP SDU may be discarded before the PDCP SDU is transferred to a lower layer (e.g., the RLC layer). As another example, the PDCP PDU may be discarded. For example, the PDCP PDU may be discarded when the PDCP PDU has already been transferred to a lower layer (e.g., the RLC layer). When the PDCP layer discards the PDCP PDU, it may be assumed that the delivery of the PDCP PDU has been confirmed. The transmission window in the PDCP layer may be advanced. As another example, the discarding of the PDCP SDU and the discarding of the PDCP PDU may be used in combination.

[0373] As another example, the discarding operation may be performed by the RLC layer of the transmitting side device. When the RLC layer performs the discarding operation, the RLC SDU may be discarded. The RLC SDU may be discarded, for example, before the RLC SDU is transferred to a lower layer (e.g., MAC layer). As another example, the RLC PDU may be discarded. The RLC PDU may be discarded, for example, when the RLC PDU has already been transferred to a lower layer (e.g., MAC layer). When the RLC layer discards the RLC PDU, it may be assumed that the delivery of the RLC PDU has been confirmed. The transmission window in the RLC layer may be advanced. As another example, the discarding of the RLC SDU and the discarding of the RLC PDU may be used in combination.

[0374] As another example, the discard operation may be performed by the MAC layer of the transmitting device. When the MAC layer performs the discard operation, the discard operation may be performed in the processing of the LCP.

[0375] The discarding operations in each layer of the transmitting device may be combined. For example, the PDCP layer may discard PDCP SDUs and PDCP PDUs, and the RLC layer may discard RLC PDUs. This makes it possible to prevent data from being stuck in each of the layers mentioned above.

[0376] As another example, the discard operation may be performed in the receiving device. The discard operation may be performed by the application layer, the SDAP layer, or the PDCP layer of the receiving device. When the PDCP layer performs the discard operation, the PDCP layer may discard the PDCP PDU. When discarding the PDCP PDU, the PDCP layer may consider the PDCP PDU as a normal reception (ACK). When discarding the PDCP PDU, the PDCP layer may advance the reception window of the PDCP layer.

[0377] As another example, the discard operation may be performed in an RLC layer of the receiving device. When the RLC layer performs the discard operation, the RLC layer may discard the RLC PDU. When discarding the RLC PDU, the RLC layer may consider the RLC PDU as a normal reception (ACK). When discarding the RLC PDU, the RLC layer may advance the receiving window of the RLC layer.

[0378] As another example, the discarding operation may be performed in the MAC layer of the receiving device. When the MAC layer performs the discarding operation, the received transport block may be discarded. As another example, logical channel data extracted from the transport block may be discarded. This makes it possible to prevent packet loss due to discarding of the other logical channels even when, for example, a jitter-critical logical channel and other logical channels are multiplexed in the same transport block.

[0379] In performing the discard operation, the MAC layer of the receiving device may transmit a HARQ-ACK as HARQ feedback for the transport block to be discarded.

[0380] The discarding operations in each layer of the receiving device may be combined, which makes it possible to prevent data from being stuck in each layer of the receiving device, for example.

[0381] As another example, the discarding operation may be performed in both the transmitting device and the receiving device. When the discarding operation is performed in both the transmitting device and the receiving device, the method disclosed in the fourth modification of the first embodiment may be used in combination. This makes it possible to reduce memory usage in the communication system, for example.

[0382] The discarding operation may be predefined by a standard. For example, the presence or absence of the discarding may be defined, and an entity that performs the discarding (e.g., a transmitting device and / or a receiving device) may be defined.

[0383] The discarding operation may be determined using QoS parameters. The information included in the QoS parameters may be, for example, information on jitter tolerance, information on latency requirements, or information on the above-mentioned broad range. Information on network slicing (e.g., NSSAI (Network Slice Selection Assistance Information)) may be used.

[0384] As another example, the discarding action may be determined in the base station and notified to the UE via RRC signaling, MAC signaling, L1 / L2 signaling, or a combination of the above.

[0385] As another example, the discard operation may be determined in an upper NW device and notified to the UE. The notification may be performed via a base station. For example, NAS signaling may be used for the notification. Alternatively, for example, a combination of signaling used in the interface between the upper NW device and the base station and the above-mentioned signaling used for notification from the base station to the UE may be used for the notification.

[0386] The information notified to the UE from the base station and / or the upper NW device may include information identifying the data on which the discard operation is performed. The information identifying the data may be, for example, a PDU session, a bearer, a logical channel, a QoS flow, information related to network slicing, or a combination of a plurality of the above.

[0387] As another example, the information may include information regarding a QoS condition (e.g., a threshold) for which the discard operation is performed. The UE may perform the discard operation for data that satisfies the condition. As another example, the UE may perform the discard operation for data that does not satisfy the condition.

[0388] As another example, the information may include information regarding the broad range of topics discussed above.

[0389] The receiving device may hold the data until a timing when no jitter occurs. The receiving device may transfer the data to a higher layer at that timing. The data may be held, for example, in an application layer, at an input end to the application layer, in an SDAP, in a PDCP layer, in an RLC layer, or in a MAC layer. The same may be done for data with a latency requirement. For example, the receiving device may hold the data until a timing when a predetermined latency occurs. The receiving device may transfer the received data to a higher layer at that timing. This makes it possible to improve, for example, the jitter characteristics through the communication system.

[0390] The base station may notify the UE of the timing-related information by using RRC signaling, MAC signaling, or L1 / L2 signaling.

[0391] The transmitting device may notify information on the transmission time of the transmission data, or may notify information on the time when the receiving device should receive the data. The time when the data should be received may be, for example, the time when the receiving device should transfer the data to the upper layer. The time may be, for example, a time in milliseconds, a time using a subframe number, a time using a slot number, a time using a minislot number, a time using a symbol number, or a combination of two or more of the above. The transmitting device may, for example, add a timestamp to the transmission data. The timestamp may be information similar to the above-mentioned time. The timestamp may be added in an upper layer, in an SDAP, in a PDCP, in an RLC, or in a MAC. As another example, the information on the transmission time may be notified using an RRC signaling, in a MAC signaling, or in an L1 / L2 signaling. The receiving device may derive the timing using the information on the transmission time. The receiving device may remove the timestamp from the received data. This makes it possible to maintain a constant latency in data transmission and reception, i.e., to reduce jitter.

[0392] According to the fourth modification of the first embodiment, data that falls outside the jitter tolerance range is discarded, which makes it possible to reduce the amount of processing in the communication system and to discard data in the logical channel.

[0393] Embodiment 2 In a NR cell, a dormant state as described in Non-Patent Document 24 (TS36.321 V15.2.0) may be applied. The UE may transition the communication state with the gNB cell to a dormant state or an active state using MAC signaling from the gNB.

[0394] However, when a cell configured for packet duplication using CA is in a dormant state, the gNB needs to notify the UE of the MAC signaling to release the dormant state prior to packet duplication communication, which causes problems such as a delay in starting packet duplication communication and an increase in latency.

[0395] A solution to the aforementioned problems is disclosed.

[0396] A cell for which packet duplication is configured is not put into a dormant state. The dormant state may be disabled. A timer used to implicitly transition a cell to a dormant state may be disabled. A timer used to implicitly stop communication of a dormant SCell (for example, dormantSCellDeactivationTimer shown in Non-Patent Document 24) may be disabled.

[0397] As another example, a cell in which packet duplication is set may not be in a deactivate state, and a cell in which packet duplication is set may be in an activate state or a dormant state only, which allows, for example, packet duplication to be quickly resumed.

[0398] As another example, a cell for which packet duplication is activated may not be put into a dormant state. The dormant state may be disabled. A timer used to implicitly transition a cell to a dormant state may be disabled. A timer used to implicitly stop communication of a dormant SCell may be disabled.

[0399] As another example, a cell for which packet duplication is activated may be placed in an activated state, and the transition to the activated state may be performed without MAC signaling indicating cell activation, which may reduce the amount of signaling from the base station to the UE, for example.

[0400] Of the MAC signaling for instructing start / stop of packet duplication, the MAC signaling for instructing cell suspension / resumption of suspension, and the MAC signaling for instructing cell activation / deactivation, two or all three may be integrated together, which makes it possible to reduce, for example, the amount of signaling from the base station to the UE.

[0401] Alternatively, packet duplication may be performed using a non-dormant cell, which may for example be an active cell, e.g., thereby making it possible to avoid undormant cells and thus to perform packet duplication quickly.

[0402] The UE may prioritize the MAC signaling of packet duplication over the MAC signaling of SCell quiescing / releasing. As another example, the UE may prioritize the MAC signaling of SCell quiescing / releasing over the MAC signaling of packet duplication. The above-mentioned priority operation may be applied when both MAC signalings are transmitted simultaneously or at different timings. It is possible to prevent malfunctions due to discrepancies in cell conditions between the base station and the UE.

[0403] An operation may be defined by combining the MAC signaling for instructing packet duplication to start / stop, the MAC signaling for instructing cell suspension / resumption of suspension, and the MAC signaling for instructing cell activation / deactivation. This makes it possible to prevent malfunctions due to, for example, discrepancies in cell status between the base station and the UE.

[0404] SCell dormancy may be applied to both uplink and downlink communications. For example, the SCell may be activated in uplink communications and dormant in downlink communications. The same may be applied to SCell activation / deactivation and packet duplication. An identifier indicating uplink or downlink may be added to MAC signaling from the base station to the UE. This allows, for example, a communication system to be operated more flexibly.

[0405] The operation in the second embodiment may be applied to LTE. This makes it possible to quickly perform packet duplication even in the case of packet duplication using LTE, for example.

[0406] According to the second embodiment, the UE can quickly perform packet duplication even for an idle cell.

[0407] Variation 1 of embodiment 2 A UE using CA may suspend communication with the SCell. The SCell may be an LTE cell, an NR cell, or even a next-generation cell. A base station may explicitly instruct a UE to suspend communication with the SCell. For example, MAC signaling may be used for the instruction. As another example, the UE may implicitly suspend communication with the SCell. When the UE implicitly suspends communication, a timer may be used. The UE may suspend communication with the SCell when the timer expires. A UE that has suspended communication with the SCell may stop communication with the SCell.

[0408] However, Non-Patent Document 24 does not disclose a method for implicitly stopping communication with an SCell after implicitly pausing communication with the SCell. This makes it impossible to implicitly stop communication with the SCell after implicitly pausing communication with the SCell. This causes a problem of increased power consumption in the UE.

[0409] A method for solving the above-mentioned problems is disclosed. After implicit SCell communication pause, the UE starts a timer used for implicit communication stop of the dormant SCell. The UE may stop communication with the dormant SCell when the timer expires. The timer may be the same timer (e.g., dormantSCellDeactivationTimer shown in Non-Patent Document 24) that is started when SCell communication is paused by an explicit instruction from the base station. This makes it possible to avoid complexity in communication system design, for example.

[0410] The value of the timer may be the same or different between the case where the UE explicitly pauses SCell communication and the case where the UE implicitly pauses SCell communication. As an example of a case where the timer value is different, the UE may use a value obtained by subtracting a predetermined value from the value of the timer as the initial value of the timer. For example, when the UE implicitly pauses SCell communication, the above-mentioned subtracted value may be used as the initial value of the timer. This allows, for example, the UE to quickly stop communication with a paused SCell, and as a result, power consumption in the UE can be reduced.

[0411] As another example, the timer used for implicitly stopping communication with a dormant SCell may be different from the timer started when communication with the SCell is suspended by an explicit instruction from the base station. This can provide, for example, the same effect as described above.

[0412] According to this first modification of the second embodiment, the UE can perform an implicit transition to SCell suspension after an implicit transition to SCell suspension. As a result, it is possible to reduce the amount of signaling between the base station and the UE, and also possible to reduce power consumption in the UE.

[0413] Variation 2 of embodiment 2 The UE may perform measurements of cells even in RRC_IDLE or RRC_INACTIVE state, and may report the measurement results to the base station.

[0414] However, the measurement method and the method of reporting the measurement result for a UE in the RRC_IDLE or RRC_INACTIVE state are not disclosed, so the UE cannot perform the measurement and cannot report the measurement result to the base station.

[0415] In this second modification of the second embodiment, a method for solving the above-mentioned problems will be disclosed.

[0416] A UE in RRC_IDLE or RRC_INACTIVE state may measure SS blocks.

[0417] The base station may notify the UE of information regarding the SS blocks that the UE measures, for example, before the UE transitions from the RRC_CONNECTED state to the RRC_IDLE or RRC_INACTIVE state.

[0418] The information may include an identifier of a cell to be measured, information about the frequency of an SS block to be measured, an identifier of the SS block, information about timing, or information about a subcarrier interval at which the SS block is measured. The timing information may be, for example, information about a frame timing offset between a cell to which the UE is connected and a cell to be measured, or information about a time position of the SS block included in an SS burst of the cell. A plurality of pieces of information may be provided. For example, the number of pieces of information may be the same as the number of cells and / or beams to be measured. The UE may use the information to measure the SS block. This allows, for example, a UE in RRC_IDLE or RRC_CONNECTED to quickly measure an SS block.

[0419] As another example, a UE in RRC_IDLE or RRC_INACTIVE state may measure the CSI-RS, and the base station may notify the UE of information regarding the CSI-RS that the UE measures, for example, before the UE transitions from RRC_CONNECTED state to RRC_IDLE or RRC_INACTIVE state.

[0420] The information may include an identifier of a cell to be measured, information about the frequency of the CSI-RS, information about timing, information about the arrangement in frequency and time resources, information about the subcarrier interval at which the CSI-RS is measured, or information about a code pattern. The timing information may be, for example, information about a frame timing offset between a cell to which the UE is connected and a cell to be measured. A plurality of pieces of information may be provided. For example, the number of pieces of information may be the same as the number of cells and / or beams to be measured. The UE may use the information to measure the CSI-RS. This allows, for example, a UE in RRC_IDLE or RRC_CONNECTED to quickly measure the CSI-RS.

[0421] As another example, a UE in RRC_IDLE or RRC_INACTIVE state may measure both SS blocks and CSI-RS. The base station may provide a combined notification of the SS blocks and the CSI-RS to the UE. This may allow the base station to quickly restore the RRC connection of the UE, for example.

[0422] A measurement event in RRC_IDLE and / or RRC_INACTIVE may be provided. The measurement event may be an event for a measurement result of a cell or an event for a measurement result of a beam. The measurement event may be, for example, the same as the measurement event in RRC_CONNECTED. As another example, the measurement event may occur when a condition for cell reselection is satisfied. The base station may configure the UE with respect to the measurement event. The UE may report the measurement result to the base station by the occurrence of the measurement event. This allows, for example, the UE to quickly notify the base station of the cell measurement result.

[0423] The report may be made, for example, by using RRC signaling. The UE may transition to RRC_CONNECTED upon the report. After the report is completed, the base station may instruct the UE to transition to RRC_INACTIVE or RRC_IDLE.

[0424] The UE may include the measurement report in a RAN Notification Area Update (RNAU) notification to the base station. The UE may notify the measurement report together with the RNAU notification. This eliminates the need for the UE to transition from RRC_INACTIVE to RRC_CONNECTED in order to notify only the measurement report. As a result, it is possible to reduce power consumption in the UE.

[0425] As another example, the UE may include the measurement report in a notification of a Tracking Area Update (TAU) to the base station. The UE may notify the measurement report together with the notification of the TAU. This eliminates the need for the UE to return from RRC_IDLE to RRC_CONNECTED in order to notify only the measurement report. As a result, it is possible to reduce power consumption in the UE.

[0426] In the RRC_CONNECTED transition instruction from the base station to the UE, the RRC parameters already set before the transition to RRC_IDLE or RRC_INACTIVE may not be notified. The RRC parameters may be, for example, settings related to a PDU session, bearer settings, or logical channel settings. The RRC parameters may be SDAP settings, PDCP settings, RLC settings, MAC settings, or PHY settings. The UE may hold the already set RRC parameters after the transition to RRC_IDLE or RRC_INACTIVE. This makes it possible to reduce the amount of signaling from the base station to the UE. As a result, it becomes possible for the UE to quickly report the measurement result to the base station.

[0427] According to this second modification of the second embodiment, the UE can notify the measurement result in the RRC_IDLE or RRC_INAVTIVE state with low power consumption.

[0428] Embodiment 3 In 3GPP, Side Link (SL) is supported for D2D (Device to Device) communication and V2V (Vehicle to Vehicle) communication (see Non-Patent Document 1). SL is defined by the PC5 interface.

[0429] The physical channels used for SL (see Non-Patent Document 1) will be described below. A physical sidelink broadcast channel (PSBCH) carries information related to the system and synchronization, and is transmitted from the UE.

[0430] The physical sidelink discovery channel (PSDCH) carries sidelink discovery messages from the UE.

[0431] The physical sidelink control channel (PSCCH) carries control information from the UE for sidelink and V2X sidelink communications.

[0432] The physical sidelink shared channel (PSSCH) carries data from the UE for sidelink and V2X sidelink communications.

[0433] The transport channel used for SL (see Non-Patent Document 1) will be described below. A sidelink broadcast channel (SL-BCH) has a predetermined transport format, and is mapped to the PSBCH, which is a physical channel.

[0434] The Sidelink discovery channel (SL-DCH) has periodic broadcast transmissions of a fixed size and a predefined format. It supports both UE autonomous resource selection and eNB scheduled resource allocation. There is a collision risk with UE automatic resource selection, and there is no collision when the UE is allocated dedicated resources by the eNB. It also supports HARQ combining, but does not support HARQ feedback. The SL-DCH is mapped to the PSDCH, which is a physical channel.

[0435] The Sidelink Shared Channel (SL-SCH) supports broadcast transmission. It supports both UE autonomous resource selection and eNB scheduled resource allocation. There is a collision risk with UE automatic resource selection, and there is no collision when the UE is allocated dedicated resources by the eNB. It also supports HARQ combining, but does not support HARQ feedback. It also supports dynamic link adaptation by changing transmission power, modulation and coding. The SL-SCH is mapped to the PSSCH, which is a physical channel.

[0436] The logical channels used for SL (see Non-Patent Document 1) will be described. The Sidelink Broadcast Control Channel (SBCCH) is a channel for sidelink to broadcast sidelink system information from one UE to other UE. The SBCCH is mapped to the SL-BCH, which is a transport channel.

[0437] The Sidelink Traffic Channel (STCH) is a one-to-multiple sidelink traffic channel for transmitting user information from one UE to other UEs. STCH is used only by UEs with sidelink communication capability and UEs with V2X sidelink communication capability. Point-to-point communication between two sidelink capable UEs is also realized by STCH. STCH is mapped to the transport channel SL-SCH.

[0438] Support for V2X communication is also being considered for 3GPP's NR. The study of V2X communication in NR is being carried out based on the LTE and LTE-A systems, but the following points have been changed and added from the LTE and LTE-A systems.

[0439] In LTE, SL V2V communication was only broadcast. In NR, support for unicast and groupcast in addition to broadcast is being considered for SL V2V communication (see Non-Patent Document 22 (3GPP RP-182111)).

[0440] Fig. 27 and Fig. 28 are conceptual diagrams of SL communication. Fig. 27 shows broadcast communication, and Fig. 28 shows unicast communication. In the broadcast communication of Fig. 27, transmission is performed from UE#1 to UE#2, UE#3, and UE#4. In the unicast communication of Fig. 28, communication is performed from UE#1 to UE#2 and from UE#2 to UE#1. Bidirectional communication is performed between UE#1 and UE#2. The communication between UE#1 and UE#2 may be, for example, data, HARQ feedback (Ack / Nack), CSI report, etc.

[0441] Thus, support for unicast in SL communication is being considered for NR. Unlike broadcast, unicast requires bidirectional communication. For example, between two UEs (UE#1, UE#2), not only does UE#1 need to transmit to UE#2, but UE#2 needs to transmit to UE#1 as well. In LTE, SL communication was broadcast, so there was no need to transmit from UE#2 to UE#1.

[0442] SL communication requires the setting of communication resources. In LTE, SL communication was only broadcast, so it was necessary to only set transmission resources from UE#1 to UE#2. However, when unicast is performed in NR, it is necessary to set not only transmission resources from UE#1 to UE#2, but also transmission resources from UE#2 to UE#1. The method of setting transmission resources from UE#2 to UE#1 for unicast in NR has not yet been determined, and without such setting, bidirectional communication will not be possible.

[0443] In the third embodiment, a method for solving such a problem will be disclosed.

[0444] This disclosure describes a case where the gNB does not schedule resources for communication in SL, in other words, where the UE performs the scheduling.

[0445] A UE performs resource configuration for unicast communication. A UE performs resource configuration for bidirectional communication. The resource configuration may include resource sensing, selection of resources for transmission, and reservation of resources for transmission.

[0446] One UE may be, for example, a UE that performs data transmission first. Before the UE that performs data transmission first performs the data transmission, the UE performs resource setting for its own transmission and resource setting for transmission from a UE that performs unicast communication.

[0447] The transmission resources from each UE may be resources for data transmitted from each UE, or may be resources for HARQ feedback (Ack / Nack), CSI report, etc. Furthermore, the transmission resources from each UE may be resources for a sounding signal or channel transmitted from each UE. The data resources may include resources for initial transmission data and resources for retransmission data.

[0448] A UE that performs resource configuration for unicast communication may be, for example, a UE that transmits a control signal or channel first. Instead of a control signal or channel, control signaling may be transmitted. That is, a UE that performs resource configuration for unicast communication may be, for example, a UE that transmits control signaling first.

[0449] As a method of unicast communication, a control signal, a channel, or signaling for initiating connection establishment for unicast communication may be transmitted first. In such a case, the UE that transmits the control signal, the channel, or signaling for initiating connection establishment first may configure resources for unicast communication.

[0450] In this way, one UE that performs unicasting performs resource configuration for bidirectional communication, so that it is possible to simplify resource configuration control. Also, since one UE performs resource configuration for unicast communication, it is possible to reduce the number of UEs that perform resource configuration. Therefore, it is possible to reduce collisions with resources used by other UEs.

[0451] In unicast communication, the HARQ feedback may be accompanied by information indicating which data the HARQ feedback is for. The HARQ feedback may include information for identifying the corresponding data. In this way, the UE that transmitted the data can recognize which data the HARQ feedback is for. Also, as described above, when the UE that transmits data first performs resource configuration of the HARQ feedback resource for the data, it is good to associate the data with the resource of the HARQ feedback. The information indicating which data the HARQ feedback is for can be omitted.

[0452] Another method is disclosed. The transmitting UE sets resources for transmission. Each UE performing unicast communication sets resources for transmission by its own UE. The resources for transmission by its own UE may be resources for data, or may be resources for HARQ feedback (Ack / Nack), CSI report, etc. Furthermore, the resources for transmission by its own UE may be resources for a signal or channel for sounding transmitted by its own UE. The data resources may include resources for initial transmission data and resources for retransmission data. Furthermore, the resources for transmission by its own UE may be resources for transmitting a control signal or channel for starting connection establishment for unicast communication.

[0453] In the case of HARQ feedback, the UE that transmits the HARQ feedback performs resource configuration, which makes it impossible for the UE that transmitted the data to recognize which data the transmitted HARQ feedback information corresponds to.

[0454] In order to solve such a problem, when transmitting HARQ feedback, it is preferable to include information for identifying the corresponding data in the feedback. For example, the information may be a combination of the feedback and the information for identifying the data. Alternatively, the information for identifying the data may be scrambled in the feedback. The information for identifying the corresponding data may be, for example, information for identifying the UE that transmitted the data, such as a UE identifier. The UE that transmitted the data can recognize the feedback in which the identifier of the UE is detected as feedback information for the data transmitted by the UE.

[0455] As another example, a transmitting UE may include a specific identifier associated with the data in control information transmitted when transmitting data. A UE that receives the data may include the identifier in HARQ feedback transmitted. The UE that transmitted the data may recognize the feedback in which the identifier is detected as feedback information for the data transmitted by the UE.

[0456] In this manner, even if a UE that transmits HARQ feedback configures resources for the feedback, the data transmitting UE can receive HARQ feedback information from the data receiving UE.

[0457] In this way, one UE does not need to configure transmission resources for other UEs. Therefore, information related to transmission resource configuration, such as resource allocation information, does not need to be notified between UEs. Signaling between UEs in SL communication can be reduced. Also, each UE can configure resources appropriate to the amount of resources required for transmission by its own UE. This makes it possible to improve the efficiency of resource usage.

[0458] Another method is disclosed. In unicast communication, the transmission resource of a specific signal or channel and the transmission resource of feedback or report performed thereon may be set by the same UE. The UE that transmits the specific signal or channel may perform resource setting. This makes it possible to reduce the delay time of unicast communication.

[0459] For example, for resources for HARQ feedback, a UE that transmits data related to the feedback performs resource configuration. For example, UE#1 transmits data to UE#2, and UE#2 transmits HARQ feedback for the data to UE#1. In this case, UE#1 performs resource configuration for HARQ feedback. UE#1 performs both resource configuration for data transmission and resource configuration for HARQ feedback for the data transmission.

[0460] In the case where data communication is performed bidirectionally, for example, UE#1 transmits data to UE#2, UE#2 transmits HARQ feedback for the data to UE#1, and further, UE#2 transmits data to UE#1, and UE#1 transmits HARQ feedback for the data to UE#2. In this case, UE#1 configures resources for the data transmitted by UE#1 and the HARQ feedback transmitted by UE#2 for the data. UE#2 configures resources for the data transmitted by UE#2 and the HARQ feedback transmitted by UE#1 for the data.

[0461] In this way, the UE that transmits the HARQ feedback does not need to configure resources before the HARQ feedback. This makes it possible to shorten the period from data transmission to HARQ feedback transmission, and reduce the delay time of unicast communication.

[0462] Regarding resources for CSI reporting, a UE that transmits a signal or a channel related to the CSI reporting may configure resources. For example, UE#1 transmits CSI-RS to UE#2, and UE#2 transmits a CSI report derived from a CSI-RS reception result to UE#1. In this case, UE#1 configures resources for CSI reporting. UE#1 configures resources for CSI-RS transmission and resources for CSI reporting for the CSI-RS. The same applies to the bidirectional case.

[0463] In this way, the UE that transmits the CSI report does not need to configure resources before the CSI report. This makes it possible to shorten the period from CSI-RS transmission to CSI report transmission, and reduce the latency of unicast communication.

[0464] Another method is disclosed. Whether or not the own UE configures the transmission resources can be set. Five specific examples are disclosed below as indicators for determining whether or not the own UE configures the transmission resources.

[0465] (1) Type of service.

[0466] (2) QoS.

[0467] (3) Resource scheduling type.

[0468] (4) Type of data to be transmitted.

[0469] (5) Transmission protocol.

[0470] In the above (1), whether or not the own UE sets the transmission resources is determined according to the type of service that communicates by unicast. For example, if the service that communicates by unicast is a service that transmits data aperiodically, the own UE may set the transmission resources. On the other hand, if the service transmits data periodically, not aperiodically, one UE may set the transmission resources.

[0471] When data transmission is performed periodically, it becomes easier to derive the timing of data transmission, which makes it easier for one UE to configure transmission resources, and simplifies control.

[0472] In the above (2), the UE determines whether to configure transmission resources according to the QoS of the service communicated by unicast. For example, if the low latency characteristic required as the QoS of the service communicated by unicast is greater than a predetermined threshold, the UE may configure transmission resources. On the other hand, if the low latency characteristic required is equal to or less than the predetermined threshold, one UE may configure transmission resources.

[0473] For services that require low latency, one UE can configure transmission resources to further improve the low latency.For services that do not require low latency, the UE can configure transmission resources to further improve resource usage efficiency.

[0474] Low delay characteristics are exemplified as QoS. However, as other examples, QoS may be reliability such as packet error rate, through rate such as compensation bit rate, priority such as priority of each packet, etc. Priority of each packet may be, for example, PPPP (ProSe Per Packet Priority).

[0475] In the above (3), whether or not the own UE configures transmission resources is determined according to the type of resource scheduling used for communication in SL. For example, when the resource scheduling is dynamic scheduling, the own UE configures transmission resources, and when the resource scheduling timing is configured in advance, such as SPS (semi-persistent scheduling) or configured grant, one UE may configure transmission resources.

[0476] When resource scheduling is performed dynamically, the UE itself sets the transmission resources, which improves the resource usage efficiency. On the other hand, when resource scheduling timing is set, it becomes easy for one UE to set the transmission resources, which simplifies the control.

[0477] In the above (4), whether or not the own UE sets the transmission resource is determined according to the type of transmission data. For example, in the case of control plane transmission, control information transmission, or control signaling transmission, the own UE may set the transmission resource. On the other hand, in the case of user plane transmission or data transmission, one UE may set the transmission resource.

[0478] In the case of control-related transmission, the timing of occurrence of the transmission often occurs dynamically. Therefore, by having the UE itself set the transmission resource, it is possible to improve the resource usage efficiency. On the other hand, in the case of data transmission, the timing of occurrence of the transmission is often set in advance. Therefore, it becomes easy for one UE to set the transmission resource, and control can be simplified.

[0479] In the above (5), whether or not the own UE sets the transmission resource is determined according to the transmission protocol stack. For example, in the case of transmission by RRC, the own UE sets the transmission resource, and in the case of transmission by PHY or MAC, one UE may set the transmission resource.

[0480] In the case of transmission by RRC, the number of transmissions may be multiple, or the delay characteristic required for transmission may be loose. Therefore, it is possible for the UE to set the transmission resources. On the other hand, in the case of transmission by PHY or MAC, the number of transmissions may be small, and a low delay characteristic may be required. Therefore, it is possible to obtain a low delay characteristic by having one UE set the transmission resources.

[0481] The above is merely an example, and the present invention is not limited to this and may be appropriately set according to the judgment index.

[0482] The setting of whether or not the own UE configures the transmission resources may be statically determined in advance by a standard or the like. The gNB may notify the UE of the setting. The notification method may be a broadcast or an individual notification. When the individual notification is made, for example, RRC signaling, MAC signaling, or L1 / L2 control signaling may be used. Also, whether or not the own UE configures the transmission resources may be set in advance in the UE. For example, the setting information may be pre-configured in the SIM in the UE. Also, the setting method may be notified between UEs.

[0483] The above methods may be combined as appropriate. For example, when performing unicast communication, in the connection request process, each UE that transmits performs resource setting for transmission, and in the data transmission and feedback transmission processes, one UE performs resource setting. In this way, it is possible to obtain an effect suitable for each process, signal to be transmitted, or channel.

[0484] In this way, when the UE schedules, it is possible to set transmission resources from each UE that is opposite for unicast communication, enabling bidirectional communication. By scheduling by the UE, the disclosed method can be applied even when the UE is in the coverage of the gNB and when it is not in the coverage. This allows the setting of transmission resources from each UE that is opposite for unicast communication, enabling bidirectional communication.

[0485] This section describes the case where gNB performs SL scheduling.

[0486] The gNB notifies each UE of a resource configuration for transmission. Each UE sets resources according to the resource configuration notified by the gNB and performs transmission using the resources.

[0487] A UE performing unicast communication may transmit an SR and / or a BSR to the gNB. The gNB configures transmission resources for the UE according to the SR and / or BSR received from each UE. The SR and / or BSR transmitted from each UE to the gNB is transmitted on the Uu interface. The gNB may notify the UE of the resource configuration for SR and / or BSR transmission in advance. In this way, it becomes possible to configure transmission resources for each UE performing unicast.

[0488] The gNB may notify the UE performing unicast communication in advance of resource settings for transmitting control signals / channels or control signaling in SL. For example, in unicast communication, when a connection request process is performed between UEs, the gNB notifies the UE in advance of resource settings for transmitting control signals / channels or control signaling for the connection request. In this way, it is possible to set resources for processing before unicast data transmission is performed.

[0489] Another method is disclosed. A gNB notifies one UE of resource configuration for bidirectional transmission. The gNB may transmit information indicating a destination UE of unicast communication to the UE. The gNB may transmit to the UE a resource configuration for transmission and an identifier of the UE performing the transmission in association with each other. The UE notified of the resource configuration notifies the destination UE of the unicast communication of the resource configuration notified by the gNB. Each UE sets resources according to the notified resource configuration and performs transmission using the resources.

[0490] A UE performing unicast communication may transmit an SR and / or a BSR to a gNB. The UE may transmit information indicating a destination UE of the unicast communication to the gNB. The information may be a UE identifier. The information may be included in an SR and / or a BSR and notified. The above-mentioned method may be applied as a method for transmitting an SR and / or a BSR. The gNB may detect a UE performing unicast communication from the UE that transmitted the SR and / or the BSR, and notify one of the UEs of resource configuration for bidirectional transmission.

[0491] The transmission resource configuration of the destination UE of the unicast communication may be configured blindly. The UE may configure the configuration blindly until it receives a BSR from the destination UE. The transmission resource can be configured even if the gNB does not receive an SR and / or a BSR from the destination UE. In other words, the SR and / or the BSR from the destination UE is not required. The control of the unicast communication can be simplified and the amount of signaling can be reduced.

[0492] In this way, it becomes possible to set transmission resources for each UE that performs unicast.

[0493] By using the method disclosed in the third embodiment, it is possible to set transmission resources for each UE in unicast communication. Therefore, unicast communication is possible. In addition, it is possible to set transmission resources for data transmission, a predetermined signal or channel, and transmission resources for feedback or reports performed therefor. Therefore, it is possible to improve the communication quality of unicast communication.

[0494] The UE performs resource sensing to determine resources available for communication in SL (Non-Patent Document 27). Conventional LTE SL was only broadcast, so there was only initial transmission (including repeated transmission (repetition)) and no retransmission. However, retransmission occurs in unicast communication. As such, a sensing method for cases where retransmission occurs is unknown, and a new sensing method is required to enable unicast communication. Here, a resource sensing method for unicast communication is disclosed.

[0495] In resource sensing, resources to be excluded from candidates for resources used in unicast communication include resources for retransmission in addition to resources for initial transmission. Also, resources for feedback may be included in addition to resources for initial transmission. Also, resources for other signals, channels, or signaling may be included.

[0496] In resource sensing, it is not necessary to exclude all resources set for initial transmission, retransmission, feedback, other signals / channels, or signaling as described above. For example, a threshold for exclusion may be set. For example, a threshold for received power may be set. The UE may measure the received power of these resources and exclude resources whose measured value is greater than the threshold. Although the index to be measured is the received power, it may be the received strength. It is not limited to this, and other indexes may be used.

[0497] The threshold may be determined for each resource use. For example, the exclusion threshold for initial transmission resources and retransmission resources may be the same, and the exclusion threshold for feedback resources may be different. For example, the threshold for FB signals may be lowered to reduce interference between UEs. In this way, it is possible to make the interference from other UEs different depending on the signal.

[0498] When transmitting in SL, the UE evaluates the CR (Channel Occupied Ratio) (Non-Patent Document 27). CR is the ratio of resources used by the UE. Specifically, CR is the ratio of subchannels used / used for transmission in a certain number of subframes combined before and after the decision to transmit. Since SL in conventional LTE was only for broadcast, there was only initial transmission (including repeated transmission (repetition)) and no retransmission. For this reason, the ratio of subchannels used / used for initial transmission was derived in CR.

[0499] However, retransmissions occur in unicast communication. Thus, the CR evaluation method in such a case is unknown, and a new CR evaluation method is required to enable unicast communication. Here, we disclose a CR evaluation method for unicast communication.

[0500] A UE that evaluates a CR is disclosed. In unicast communication, bidirectional communication is performed between opposing UEs. In unicast communication, a UE that transmits data or feedback, etc. evaluates a CR. In this way, the UE can determine how much data or feedback, etc. to transmit using a configured or configured resource. Transmission can be controlled so that the communication volume is preset in relation to the CR.

[0501] Another method is disclosed. In unicast communication, the UE that performs resource configuration evaluates the CR. In this way, resource selection or resource reservation can be performed so that the communication volume is preset in relation to the CR when the resource is configured. By deriving the CR in this way, congestion between UEs can be avoided when the resource is configured.

[0502] A method for deriving CR is disclosed. In unicast communication, the ratio of subchannels used / to be used for initial transmission (including repeated transmission) is derived. Retransmissions will occur in unicast communication, but whether or not retransmissions are performed depends on the communication quality. Retransmissions do not always occur, and the number of occurrences in the future (for example, after the decision to transmit) is uncertain. By not including retransmissions in this way, it is possible to reduce uncertain factors.

[0503] In the transmission control using the CR, the UE controls the transmission so that the communication amount is preset in relation to the CR. The influence of retransmission or feedback may be incorporated in the communication amount preset in relation to the CR. For example, in future transmissions, the communication amount preset in relation to the CR may be set in consideration of the ratio of subchannels used for the average number of retransmissions or the maximum number of retransmissions, and the average number of feedbacks or the maximum number of feedbacks. In this way, the influence of retransmission or feedback can be incorporated.

[0504] Another method is disclosed. A ratio of subchannels used / used for initial transmission and retransmission is derived. Alternatively, a ratio of subchannels used / used for initial transmission and feedback may be derived. Alternatively, a ratio of subchannels used / used for initial transmission, retransmission and feedback may be derived. For future retransmissions or feedback, resource reserved subchannels may be used.

[0505] Alternatively, a predetermined number of future occurrences of retransmission or feedback may be preset. The predetermined number may be, for example, an average number of retransmissions or a maximum number of retransmissions, an average number of feedbacks or a maximum number of feedbacks. Also, for example, the future occurrences may be set according to communication quality. For example, if the communication quality is worse than a predetermined value, the number of future occurrences is set to be large, and if the communication quality is better than the predetermined value, the number of future occurrences is set to be small.

[0506] In this way, the effect of retransmission or feedback can be taken into account when deriving CR, making control easier. By using such a CR evaluation method in unicast communication, CR evaluation becomes possible even when retransmission occurs, making it possible to control congestion avoidance between UEs.

[0507] Packet duplication is supported in NR. Here, a method of packet duplication using unicast communication is disclosed. In unicast communication, each of the opposing UEs performs resource configuration for unicast communication. For example, the UE that transmits data performs resource configuration, and the UE that receives data performs resource configuration. Data transmission is performed using these two resource configurations. The UE performs data transmission by packet duplication using these two resource configurations.

[0508] For example, a case will be disclosed in which UE#1 transmits data to UE#2. UE#1 configures resources for data transmission. Also, UE#1 requests UE#2 to configure resources for data transmission. This may be notified by providing data transmission resource configuration request signaling. This request may be made before UE#1 configures resources for data transmission. The request may include information required for resource configuration.

[0509] Information required for resource configuration includes QoS, priority, data generation timing, data generation cycle, buffer status, etc. The information may also include an identifier of the UE that sent the request. UE#2 that receives the resource configuration request performs resource configuration using the information. UE#2 notifies UE#1 of the configured resource configuration.

[0510] In this way, UE#1 can recognize the resource settings set by its own UE and the opposing UE#2. UE#1 performs packet duplication using PDCP. UE#1 transmits one of the duplicated packets using the resources set by its own UE, and transmits the other packet using the resources set by UE#2. An LCH may be set for each resource setting. UE#1 maps the duplicated packets to different LCHs, transmits one LCH using the resources set by its own UE, and transmits the other LCH using the resources set by UE#2.

[0511] In this way, data to be transmitted from UE#1 to UE#2 can be packet-duplicated, and the duplicated packet can be transmitted using resources set by UE#1 and resources set by UE#2.

[0512] In resource configuration in UE#1, UE#1 performs resource sensing and resource selection. In resource configuration in UE#2, UE#2 performs resource sensing and resource selection. The resources sensed and selected by UE#1 are different from the resources sensed and selected by UE#2. One reason for this is that the locations of UE#1 and UE#2 are different, and therefore the presence status of other UEs in the vicinity are different. This is because the presence status of other UEs in the vicinity is different, and therefore the status of resources being used is also different between UE#1 and UE#2.

[0513] Therefore, the communication quality is different between the resource set by UE#1 and the resource set by UE#2. By using these resources with different communication qualities for transmitting the duplicated packet data, it is possible to increase the delivery probability of the duplicated packet data. It is possible to improve the reliability of communication.

[0514] Variation 1 of embodiment 3 In LTE, SL communication is only broadcast, and unlike unicast, communication is not performed between two UEs. In other words, in LTE, communication between two UEs is connectionless. In NR, unicast is being considered as SL communication. It has been proposed to establish a connection between two UEs for SL unicast and communicate, but the method of establishing the connection is unclear. For this reason, the processing up to unicast communication is unclear. In this first modification, a method for solving such problems is disclosed.

[0515] An example of unicast communication content is disclosed. Unicast communication may be composed of only one-way data or RS transmission and response transmission thereto. The data transmission may be user-plane data transmission. For example, unicast communication may be composed of data and its feedback, or data and SRS, or CSI-RS and its CSI report, or SRS and its SRI, or the like. These may be combined.

[0516] Another example of the content of communication in unicast is disclosed. The unicast communication may be composed of bidirectional data or RS transmission and a response transmission thereto. The data transmission may be user plane data transmission. For example, the unicast communication may be composed of bidirectional data and feedback thereto, or bidirectional data and SRS, or bidirectional CSI-RS and CSI report thereto, or bidirectional SRS and SRI thereto, or the like. These may be combined.

[0517] A processing method for unicast communication between two UEs for SL unicast is disclosed. A signal / channel is provided for the UE to indicate its intention to transmit. Signaling may be provided for the UE to indicate its intention to transmit. A control signal / channel or signaling may be provided. A control plane signal / channel or signaling may be provided. A UE in which a transmission in SL occurs transmits a signal / channel to indicate its intention to transmit. The signal / channel may be transmitted by broadcast. Six specific examples of information to be included in the signal / channel are shown below.

[0518] (1) Information indicating the intention to send.

[0519] (2) Information regarding the service.

[0520] (3) Information about the target UE (the opposing UE in bidirectional communication).

[0521] (4) Information about the source UE (own UE).

[0522] (5) Information regarding resource settings for responses.

[0523] (6) A combination of (1) to (5).

[0524] The information on the service in (2) above may be an identifier for identifying the service. The information in (2) above may include information on the QoS of the service. The information in (2) above may include information on the priority level.

[0525] The information on the target UE in (3) above may be a UE identifier. The information in (3) above may be information for identifying a UE with which bidirectional communication is conducted. The information in (3) above may include information on one or more target UEs. The information in (3) above may be information on a group to which the target UE belongs. For example, it may be an identifier of the group.

[0526] The information on the source UE in (4) above may be an identifier of the UE. The information in (4) above may be any information for identifying the UE that transmits the signal / channel. The information in (4) above may be information indicating the state of the UE. The information may be, for example, location information or moving speed information of the UE. The information in (4) above may be group information. The information may be information of a group that includes the source UE. The information may be, for example, an identifier of the group.

[0527] The information on response resource configuration in (5) above may be resource configuration information for a response signal / channel transmitted from the target UE to the source UE for the signal / channel. The information in (5) above may include scheduling information such as resource allocation. When the response resource configuration is performed by the target UE, the information may be omitted.

[0528] A new signal / channel for indicating the intention to transmit may be provided. As another method, the PSBCH used in D2D communication may be used. The above-mentioned information may be included as the broadcast information of the PSBCH. A UE in which a transmission in SL occurs transmits a PSBCH including the above-mentioned information to indicate the intention to transmit.

[0529] As another method, the PSDCH used in D2D communication may be used. The above-mentioned information may be included in the PSDCH. When a UE is requested to transmit in the SL, the UE transmits the PSDCH including the above-mentioned information to indicate its intention to transmit.

[0530] The signal / channel for indicating the intention to transmit may be transmitted periodically. The signal / channel may be transmitted periodically for a predetermined period or number of times. If a response signal / channel to the signal / channel is not received even after the signal / channel is transmitted for a predetermined period or number of times, the transmission of the signal / channel for indicating the intention to transmit may be stopped. Alternatively, the signal / channel may be transmitted periodically again for a predetermined period or number of times. If a response signal / channel to the signal / channel is not received for a predetermined number of retransmissions or a period for retransmission, the transmission of the signal / channel for indicating the intention to transmit may be stopped. Also, if a response signal / channel to the signal / channel is received, the transmission of the signal / channel for indicating the intention to transmit may be stopped.

[0531] Although the condition for stopping transmission of a signal / channel for indicating an intention to transmit is exemplified as a case where a response signal / channel to the signal / channel is not received, the condition for stopping may be a case where an opposite UE cannot be detected. This is effective in the case where multiple UEs transmit signals / channels for indicating their presence and the source UE detects an opposite UE from among the UEs.

[0532] The period, the predetermined period or number of times, the predetermined number of retransmissions, or the period for retransmission may be statically determined in advance by a standard or the like. Alternatively, the period, etc. may be notified to the UE by the gNB. Alternatively, the UE may determine the period, etc. An upper layer in the UE may determine the period, etc.

[0533] A signal / channel is provided for the UE to indicate its presence. Signaling may be provided for the UE to indicate its presence. A control signal / channel or signaling may be provided. A control plane signal / channel or signaling may be provided. When the UE receives a signal / channel indicating an intention to transmit from a source UE and determines that the UE is an opposing UE from the information contained in the signal / channel, the UE transmits a signal / channel indicating the UE's presence as a response signal / channel to the signal / channel. The signal / channel indicating the UE's presence may be transmitted by broadcast. Five specific examples of information to be included in the signal / channel indicating the UE's presence are shown below.

[0534] (1) Information indicating existence.

[0535] (2) Information regarding the service.

[0536] (3) Information about the target UE (own UE).

[0537] (4) Information about the source UE (the opposing UE in bidirectional communication).

[0538] (5) A combination of (1) to (4).

[0539] The information indicating the presence of the above (1) may be information indicating that the UE is the target of a signal / channel indicating an intention to transmit. Reliability can be improved by explicitly notifying the information. The target UE in the above (3) is the own UE. The source UE in the above (4) is the opposing UE in bidirectional communication, in other words, the UE that transmitted the signal / channel indicating an intention to transmit.

[0540] The information regarding the target UE (own UE) in (3) above may be an identifier of the UE. The information in (3) above may be information for identifying the UE that transmits the signal / channel. The information in (3) above may be information indicating the state of the UE. The information may be, for example, location information or moving speed information of the UE. The information in (3) above may be group information. The information may be information of a group that includes the own UE. The information may be, for example, an identifier of the group.

[0541] The information on the source UE in (4) above may be a UE identifier. The information in (4) above may be information for identifying a peer UE in bidirectional communication. The information in (4) above may be group information. The information may be information on a group including the source UE. The information may be, for example, a group identifier.

[0542] A new signal / channel for the UE to indicate its presence may be provided. Alternatively, the PSCCH or the PSSCH may be used. The PSCCH and the PSSCH may be used together. For example, information to be included in the signal / channel for indicating the presence of the UE may be included in the PSCCH and transmitted. Also, for example, a part or all of the information to be included in the signal / channel for indicating the presence of the UE may be included in the PSSCH and transmitted, and the scheduling information of the PSSCH and the remaining information to be included in the signal / channel for indicating the presence of the UE may be notified by including it in the PSCCH.

[0543] The resource configuration for transmitting the signal / channel may use information on response resource configuration included in the signal / channel for indicating the intention of transmission. Alternatively, the target UE may perform resource configuration for the signal / channel. This is effective when information on response resource configuration is not included.

[0544] Provide signaling for a connection request. A signal / channel for a connection request may be provided. A control signal / channel or signaling may be provided. A control plane signal / channel or signaling may be provided. A UE that has generated a transmission in SL transmits a connection request signaling for unicast to a peer UE that performs unicast. Six specific examples of information to be included in a connection request are shown below.

[0545] (1) Information indicating that this is a connection request.

[0546] (2) Information regarding the service.

[0547] (3) Information about the target UE (the opposing UE in bidirectional communication).

[0548] (4) Information about the source UE (own UE).

[0549] (5) Information regarding resource settings for responding to connection requests.

[0550] (6) A combination of (1) to (5).

[0551] The information on the target UE in (3) above may be a UE identifier. The information in (3) above may be information for identifying the UE with which the bidirectional communication is performed. The information in (3) above may be information on one target UE.

[0552] The information on the resource setting for the connection request response in the above (4) may be resource setting information of the connection request response signaling transmitted from the target UE to the source UE in response to the connection request. The information in the above (4) may include scheduling information such as resource allocation. When the resource setting for the connection request response is performed by the target UE, the information may be omitted.

[0553] A new signal / channel for the connection request may be provided. Alternatively, the PSCCH may be used, or the PSSCH may be used. The PSCCH and the PSSCH may be used together. For example, information to be included in the connection request may be included in the PSCCH and transmitted.

[0554] Alternatively, the information to be included in the connection request may be notified by RRC signaling or MAC signaling. For example, a part or all of the information to be included in the connection request may be transmitted in a PSSCH, and the scheduling information of the PSSCH and the remaining information to be included in the connection request may be transmitted in a PSCCH.

[0555] The method of transmitting the connection request signaling may be the same as the method of transmitting a signal / channel for indicating an intention to transmit.

[0556] A connection request response signaling is provided. A signal / channel for the connection request response may be provided. A control signal / channel or signaling may be provided. A control plane signal / channel or signaling may be provided. When a unicast counterpart UE receives a connection request signaling from a source UE, it transmits a connection request response signaling. Seven specific examples of information to be included in the connection request response are shown below.

[0557] (1) Information regarding connection request responses.

[0558] (2) Information regarding the service.

[0559] (3) Information about the target UE (own UE).

[0560] (4) Information about the source UE (the opposing UE in bidirectional communication).

[0561] (5) Scheduling request (SR).

[0562] (6) BSR (Buffer Status Report).

[0563] (7) A combination of (1) to (6).

[0564] The information on the connection request response in the above (1) may be an authorization response or a rejection response. The information in the above (1) may include reason information. Alternatively, the information in the above (1) may be Ack or Nack information. By providing the rejection response or Nack information, it becomes possible for the target UE to determine whether or not to perform a connection depending on the load situation and capabilities of the target UE.

[0565] The scheduling request in (5) above may be sent when there is data to be transmitted from the target UE to the source UE, or when there is a possibility that data will be transmitted.

[0566] Regarding the BSR in (6) above, if there is data to be transmitted from the target UE to the source UE, or if there is a possibility of such data being transmitted, the target UE may notify the source UE of the amount of buffered data. Alternatively, the amount of data that needs to be transmitted may be notified. As the amount of buffered data, the amount of data buffered in the user plane protocol for SL may be used. For example, the amount of data buffered in the PDCP for SL and / or the RLC for SL may be used.

[0567] The source UE that has received the above (5) and / or (6) can determine whether to configure resources for data transmission to the target UE and can also determine the amount of resources to reserve.

[0568] A new signal / channel for the connection request response may be provided. Alternatively, the PSCCH may be used, or the PSSCH may be used. The PSCCH and the PSSCH may be used together. For example, information to be included in the connection request response may be included in the PSCCH and transmitted.

[0569] Alternatively, the information to be included in the connection request response may be notified by RRC signaling or MAC signaling. For example, a part or all of the information to be included in the connection request response may be transmitted in a PSSCH, and the scheduling information of the PSSCH and the remaining information to be included in the connection request response may be transmitted in a PSCCH.

[0570] The resource configuration for the connection request response may use the information on the resource configuration for the connection request response included in the connection request signaling. Alternatively, the target UE may perform the resource configuration for the connection request response. This is effective when the information on the resource configuration for the connection request response is not included.

[0571] A signal / channel for data transmission scheduling is provided. A UE in which transmission occurs in SL transmits a signal / channel for data transmission scheduling. Five specific examples of information to be included in the signal / channel are shown below.

[0572] (1) Resource scheduling information for data and / or feedback transmission.

[0573] (2) Information regarding the service.

[0574] (3) Information about the target UE (the opposing UE in bidirectional communication).

[0575] (4) Information about the source UE (own UE).

[0576] (5) A combination of (1) to (4).

[0577] The resource scheduling information for data and / or feedback transmission in the above (1) may include resource allocation information for transmission from the source UE to the target UE and / or resource allocation information for transmission from the target UE to the source UE. The resource allocation information may include resource allocation information for data transmission and / or resource allocation information for transmission of feedback, reports, etc. Data transmission is not limited to transmission of initial transmission data, and may be repeated transmission or retransmission of data. These pieces of information may be appropriately combined and included in the scheduling information for data and / or feedback transmission.

[0578] A new signal / channel for transmitting the scheduling information for data transmission may be provided. Alternatively, the PSCCH may be used. For example, the information to be included in the connection request response may be included in the PSCCH and transmitted.

[0579] Alternatively, the information to be included in the connection request response may be notified by RRC signaling or MAC signaling. For example, a part or all of the information to be included in the connection request response may be transmitted in a PSSCH, and the scheduling information of the PSSCH and the remaining information to be included in the connection request response may be transmitted in a PSCCH.

[0580] The method of transmitting the scheduling information for data transmission may be a method of transmitting a signal / channel for indicating an intention to transmit.

[0581] A data transmission signal / channel is provided. A UE in which transmission occurs in SL transmits a data transmission signal / channel. The data transmission signal / channel may be transmitted according to data transmission scheduling information. Seven specific examples of information to be included in the data transmission signal / channel are shown below.

[0582] (1) Data.

[0583] (2) RS.

[0584] (3) Ack / Nack.

[0585] (4) CSI.

[0586] (5) S.R.

[0587] (6) BSR.

[0588] (7) A combination of (1) to (6).

[0589] The RS in (2) above may be an RS for data demodulation. Alternatively, the RS in (2) above may be an RS for channel evaluation, for example, a CSI-RS or an SRS. Alternatively, the RS in (2) above may be an RS for positioning. The RS may be transmitted separately from a channel including data. The Ack / Nack in (3), the CSI in (4), the SR in (5), and the BSR in (6) may be transmitted alone or in combination with data. The Ack / Nack in (3) and the like may be piggybacked with data and transmitted on a channel for data transmission.

[0590] A new signal / channel for data transmission may be provided. Alternatively, PSSCH may be used.

[0591] Fig. 29 is a first example of a sequence up to unicast communication between two UEs for SL unicast. Fig. 29 shows a case where UE_A generates data to transmit to UE_B in SL. Bidirectional unicast communication is performed between UE_A and UE_B. As a sequence up to unicast communication, an opposing UE detection phase, a connection establishment phase, and a data transmission phase may be provided.

[0592] In the example of Fig. 29, the opposed UE detection phase consists of the sequence from step ST5103 to step ST5106. The connection establishment phase consists of the sequence from step ST5107 to step ST5108. The data transmission phase consists of the sequence from step ST5110 to step ST5112. Unicast communication is performed in the data transmission phase.

[0593] The opposing UE detection phase and / or the connection establishment phase may be a process of the control plane. Signaling of the control plane may be used for communication in the opposing UE detection phase and / or the connection establishment phase. An RRC protocol for SL may be provided. The opposing UE detection phase and / or the connection establishment phase may be a process in the RRC protocol for SL. By using such a process for control, it is possible to facilitate the control process up to unicast communication between two UEs.

[0594] In step ST5101, UE_A generates transmission data in SL to UE_B. In step ST5102, UE_A senses resources for a signal / channel transmission to indicate an intention to transmit, selects resources, and reserves resources. At this time, UE_A may sense resources for a signal / channel to indicate its presence, select resources, and reserve resources.

[0595] In step ST5103, UE_A transmits a signal / channel to indicate its intention to transmit. UE_A may transmit the signal / channel by broadcast. This allows UE_A to indicate that it has data to transmit. In step ST5104, UE_B receives the signal / channel to indicate its intention to transmit from UE_A, and detects that it is a target or a target candidate from the information contained therein.

[0596] In Step ST5105, UE_B transmits a signal / channel for indicating its presence to UE_A. The signal / channel may include identifier information of the source UE to indicate that the signal / channel is for UE_A. Alternatively, the signal / channel may be for UE_A by using resource setting information for the presence response notified in Step ST5103 to set resources for transmitting the signal / channel for indicating its presence.

[0597] Multiple UEs may be target candidates and multiple UEs may transmit signals / channels to indicate their presence to UE_A.

[0598] In step ST5106, UE_A detects an opposing UE for unicast bidirectional communication. UE_A may store a UE once detected. UE_A may store a UE once detected for a predetermined period. For example, if UE_A cannot detect an opposing UE within a predetermined period, UE_A may stop transmitting a signal / channel indicating an intention to transmit. The above-mentioned method may be applied. Also, if UE_A detects an opposing UE, UE_A may stop transmitting a signal / channel indicating an intention to transmit.

[0599] In step ST5107, UE_A transmits a connection request to the peer UE_B. UE_B, which receives the connection request, transmits a connection request response to UE_A in step ST5108. In the example of FIG. 29, UE_B notifies connection permission information as the connection request response. The resources reserved in step ST5102 may be used as resources for the connection request. The resources reserved in step ST5102 for the presence response may be used as resources for the connection request response. It is possible to omit the resource setting process for the connection establishment process.

[0600] Before transmitting the connection request, UE_A may newly perform sensing, resource selection, and resource reservation of resources for the connection request and resources for the connection request response, thereby enabling resource setting suitable for the connection establishment process.

[0601] In Step ST5110, UE_A transmits a signal / channel for scheduling data transmission to UE_B. The scheduling information for data transmission is included in a PSCCH and notified. In Step ST5111, UE_B detects a PSCCH including scheduling information for data transmission addressed to its own UE. In Step ST5112, UE_B receives data from UE_A in accordance with the scheduling information for data transmission included in the detected PSCCH.

[0602] Furthermore, in Step ST5112, UE_B may transmit, to UE_A, HARQ feedback for the data received from UE_A. UE_B transmits feedback in accordance with the feedback scheduling information included in the detected PSCCH.

[0603] In addition, in step ST5112, UE_B may transmit a CSI report to UE_A. Also, UE_B may transmit data to UE_A. UE_B transmits CSI or data in accordance with resource scheduling information from UE_B to UE_A included in the detected PSCCH, more specifically, in accordance with resource scheduling information for CSI report or resource scheduling information for data transmission. HARQ feedback, CSI report, or retransmission data to be transmitted from UE_A to UE_B may be transmitted in the same manner.

[0604] Before transmitting the data transmission resource scheduling information, in Step ST5109, UE_A may newly perform sensing, resource selection, and resource reservation of resources for data transmission resource scheduling in Step ST5110 and resources for unicast communication in Step ST5112. This enables resource setting suitable for unicast communication.

[0605] The resources for data transmission resource scheduling and the resources for unicast communication may be resources reserved in step ST5102 or before a connection request, making it possible to omit the resource setting process.

[0606] A scheduling method for data transmission is disclosed for the case where one UE performs resource configuration.

[0607] UE_A notifies UE_B of resource scheduling information for initial transmission, resource scheduling information for feedback, and resource scheduling information for retransmission to be transmitted from UE_A to UE_B via a PSCCH related to the initial transmission data transmission.

[0608] In addition, UE_A notifies UE_B of resource scheduling information for initial transmission, resource scheduling information for feedback, and resource scheduling information for retransmission, for transmission from UE_B to UE_A. These pieces of information may be notified by a PSCCH related to the initial transmission data transmission performed from UE_A to UE_B.

[0609] Regarding resource scheduling information for initial transmission, resource scheduling information for feedback, and resource scheduling information for retransmission to be transmitted from UE_B to UE_A, after UE_B notifies UE_A of SR or BSR, resource setting and / or notification may be performed from UE_A to UE_B. When no transmission data is generated in UE_B, there is no need to perform resource setting. This makes it possible to improve resource usage efficiency.

[0610] By having one UE configure resources for bidirectional transmission and notify the opposing UE, it is possible to obtain the same effects as those disclosed in the third embodiment.

[0611] A scheduling method for data transmission is disclosed for the case where each UE that transmits data performs resource configuration.

[0612] UE_A notifies UE_B of resource scheduling information for initial transmission, resource scheduling information for feedback, and resource scheduling information for retransmission to be transmitted from UE_A to UE_B via a PSCCH related to the initial transmission data transmission.

[0613] In addition, UE_B notifies UE_A of resource scheduling information for initial transmission, resource scheduling information for feedback, and resource scheduling information for retransmission to be transmitted from UE_B to UE_A via a PSCCH related to the initial transmission data transmission.

[0614] Each UE that transmits data configures transmission resources and notifies the corresponding UE of the transmission resources, thereby making it possible to obtain the same effects as those disclosed in the third embodiment.

[0615] In the method disclosed above, it has been shown that resource scheduling information for retransmission is included in the PSCCH related to the initial transmission data transmission and notified. As another method, resource scheduling information for retransmission may be included in the PSCCH related to the retransmission data transmission and notified. In this way, it is possible to notify resource setting after retransmission occurs. For example, when communication quality is good and retransmission does not occur, there is no need to make resource reservation for retransmission, and resource usage efficiency can be improved.

[0616] Seven examples of information to be included in the resource scheduling information are disclosed below.

[0617] (1) Resource allocation information.

[0618] (2)MCS information.

[0619] (3) Information indicating whether it is an initial transmission or a retransmission.

[0620] (4) Redundancy Version (RV) information.

[0621] (5) Information about the target UE.

[0622] (6) Information regarding the Service.

[0623] (7) A combination of (1) to (6).

[0624] Regarding the information that overlaps with the information included in the signal / channel for data transmission scheduling described above, only one of the pieces of information may be included. By omitting the overlapping information, the amount of information can be reduced.

[0625] The resource allocation information in (1) above may include resource time (timing) information, resource frequency information, resource offset information, etc. The resource time information may be periodic information.

[0626] The feedback resource offset information may be, for example, a time offset from a data transmission timing. The data transmission timing may be a first-time data transmission timing or a retransmission data transmission timing. The unit of time may be not only seconds, but also slots, subframes, minislots, TTIs, etc.

[0627] In this way, it is possible to notify the UE that transmits feedback in relation to the data transmission of the timing offset from data transmission to feedback. Also, by providing an offset from the initial data transmission timing and an offset from the retransmission data transmission timing, it is possible to set the timing of feedback for the initial transmission and the timing of feedback for the retransmission separately.

[0628] The offset information of the retransmission resource may be, for example, a time offset from the data transmission timing. The data transmission timing may be the initial data transmission timing, or the feedback transmission timing, or the retransmission data transmission timing. The unit of time may be not only seconds, but also slots, subframes, minislots, TTIs, etc.

[0629] For example, the timing of transmitting the retransmission scheduling information may be different from the timing of transmitting the retransmission data, and in such a case, the retransmission data can be received by notifying the offset information of the retransmission resource, thereby enabling flexible scheduling.

[0630] In this way, it becomes possible to set a series of transmission resources for data transmission, feedback thereto, and retransmission, and to notify the opposing UE of the set of transmission resources. This enables HARQ feedback control, and makes it possible to improve the communication quality of unicast communication.

[0631] Another method for setting and notifying the feedback resource is disclosed. Timing information and frequency information of the feedback resource may be set by UE_A, which is the relevant data transmission source. UE_A may perform resource setting. Alternatively, UE_A may set only the timing information of the feedback resource, and UE_B, which is the feedback transmission source, may set the frequency information of the feedback resource. UE_A may notify UE_B of the timing information of the feedback resource. UE_B may perform resource setting using the timing information notified from UE_A.

[0632] A predetermined resource sensing period may be set for the feedback resource configuration. This period may be set separately from the sensing period for the data resource configuration. By setting these periods separately, for example, when a feedback resource is set, it is possible to perform sensing of only the feedback resource. This makes it possible to simplify the sensing process.

[0633] A minimum offset may be set as the timing of the feedback resource. The offset information may be, for example, a time offset from the data transmission timing. The unit of time may be not only seconds, but also slots, subframes, minislots, TTIs, etc. The minimum offset may be included in the UE capability information and notified to the opposing UE that performs unicast communication. Alternatively, the minimum offset may be notified to the gNB. In this way, it is possible to set an optimal offset from the data transmission as the feedback transmission timing.

[0634] In this way, a connection for unicast communication can be established between opposing UEs (UE_A and UE_B) in the SL, which enables unicast communication between the opposing UEs.

[0635] Resource reservation for unicast communication may be performed before the connection establishment phase. The resource setting for unicast communication may be selected from the reserved resources. The resource setting for a series of transmission resources for data transmission, feedback thereon, and retransmission may use the resources reserved before the connection establishment phase.

[0636] By doing so, for example, when a plurality of unicast communications are performed over one unicast connection, it is not necessary to reserve resources for each unicast communication, and the resource setting process can be simplified.

[0637] For example, the resources reserved before the connection establishment phase are set in a wider frequency range than the resources reserved for unicast communication. UE_A may transmit a signal for channel assessment using the resources reserved before the connection establishment phase. The signal for channel assessment may be CSI-RS. Alternatively, DMRS may be used. UE_B measures the signal for channel assessment and reports the channel state to UE_A. The report of the channel state may be CSI.

[0638] In this way, UE_A can receive CSI from UE_B in a wider frequency range than the resources used for data transmission. Therefore, when the communication quality of the resources used for data transmission deteriorates, UE_A can change the resources used for data transmission. It becomes possible to set resources with better communication quality for data communication, thereby improving communication quality.

[0639] The same applies to communication quality measurement in the reverse direction. For example, UE_A sets resources for a signal, such as SRS, for sounding using resources reserved before the connection establishment phase. UE_B transmits SRS using the resources. In this way, UE_A can receive SRS from UE_B in a wider frequency range than the resources used for data transmission. Therefore, UE_A can change the resources used for data transmission when the communication quality of the resources used for data transmission from UE_B deteriorates. It becomes possible to set resources with better communication quality for data communication, thereby improving communication quality.

[0640] The process up to unicast communication has been disclosed above. Next, the process to end unicast communication will be disclosed. A condition for executing the process to end unicast communication is set. Three examples of the conditions for executing the process to end unicast communication are disclosed below.

[0641] (1) When there is no more transmission data For example, when there is no more transmission for a predetermined period or number of consecutive times, it may be determined that there is no more transmission data.

[0642] (2) If the service is terminated.

[0643] (3) When termination is notified from a higher layer.

[0644] A unicast communication termination process is disclosed. The UE notifies the opposing UE by providing connection termination signaling. The UE that receives the notification releases resources reserved for unicast communication. For example, the settings in PHY, MAC, RLC, PDCP, and / or SDAP for SL may be reset.

[0645] Signaling indicating completion of unicast communication termination may be provided. A UE that has released resources reserved for unicast communication notifies a peer UE of signaling indicating completion of unicast communication termination. A UE that receives the unicast communication termination completion signaling releases resources reserved for unicast communication. Similarly, settings may be reset in, for example, PHY, MAC, RLC, PDCP, and / or SDAP for SL.

[0646] In this way, it is possible to execute the unicast communication termination process. Therefore, it is possible to release the resources reserved for the unicast communication. Since other UEs can use the released resources, it is possible to improve the resource usage efficiency.

[0647] The unicast communication may be terminated while maintaining the unicast connection. For example, when unicast communication is to be performed again, it may be performed from the data transmission phase. A method such as that disclosed in FIG. 35 described later may be used. Also, even if the unicast communication is interrupted, the unicast connection may be maintained. For example, the unicast communication may be interrupted when data communication is not performed for a long period of time or when synchronization between UEs is lost.

[0648] A link failure may be provided in the SL. A link failure is determined to occur when a specified signal / channel cannot be received between UEs for a specified period of time. Even when a link failure occurs in such unicast communication, the unicast connection may be maintained for a specified period of time. If the link failure state continues even after the specified period of time has elapsed, the unicast connection may be terminated.

[0649] In this way, it is possible to avoid frequent unicast connection processing. Since the number of times unicast connection processing is performed can be reduced, it is possible to reduce signaling between UEs. It is possible to reduce resources used for unicast connection, and it is possible to increase resources available to other UEs. It is possible to improve resource usage efficiency. In addition, since it is possible to avoid frequent unicast connection processing, it is possible to simplify processing in the UE.

[0650] Figure 30 is a second example of a sequence up to unicast communication between two UEs for SL unicast. In Figure 30, the same step numbers are used for steps common to Figure 29, and common explanations are omitted. Figure 30 is an example in which the transmission of signals / channels to indicate presence is reduced compared to Figure 29. Instead of transmitting signals / channels to indicate presence, a connection request may be transmitted.

[0651] In Step ST5103, UE_A transmits a signal / channel for indicating its intention to transmit. The signal / channel may include a resource setting for a connection request, not a resource setting for a signal / channel for indicating its presence. In Step ST5104, UE_B receives a signal / channel for indicating its intention to transmit from UE_A, and detects that it is a target or a target candidate from the information contained therein.

[0652] A signal / channel is provided for indicating a connection request from the target UE (UE_B) to the source UE (UE_A). In step ST5201, UE_B transmits a signal / channel for indicating a connection request to UE_A. The signal / channel for indicating the connection request may include information such as SR and BSR in addition to the information to be included in the signal / channel for indicating the presence. When there is data to be transmitted from UE_B to UE_A, it is preferable to transmit SR, BSR, etc., included in the signal / channel for indicating the connection request. Also, instead of information indicating the presence, information indicating that it is a connection request may be included in the signal / channel for indicating the connection request.

[0653] In this way, the step of transmitting information indicating the presence can be reduced. Also, the step of transmitting a connection request from UE_A to UE_B can be reduced. Therefore, it is possible to reduce the amount of signaling required for connection establishment. Also, the example of FIG. 30 is a connection request that can include SR, BSR, etc., so it is more suitable for a case where one UE is the target UE than a case where multiple UEs are the target UEs.

[0654] Figure 31 is a third example of a sequence up to unicast communication between two UEs for SL unicast. In Figure 31, steps common to Figure 29 are given the same step numbers, and common explanations are omitted. Figure 31 is an example in which the transmission of signals / channels for indicating an intention to transmit and signals / channels for indicating presence are reduced compared to Figure 29. UE_A in which transmission data in SL is generated in step ST5101 performs resource sensing, resource selection, and resource reservation for connection request transmission and / or connection request response in step ST5301, and transmits connection request signaling in step ST5107.

[0655] In this way, the method disclosed in Fig. 31 is a method that omits the opposed UE detection phase. In the connection establishment phase, opposed UE detection is also performed. This is more suitable for the case where one UE is the target UE than the case where multiple UEs are the target UE.

[0656] The UE may store a UE that has once performed a unicast connection. The UE may store a UE that has once performed a unicast connection for a predetermined period of time. The UE may perform a connection process preferentially for a UE that has once performed a unicast connection. In such a case, the opposing UE detection phase may be omitted. UE_A may perform an opposing UE detection phase when it performs a connection request and cannot receive a connection response. Since a UE that has once performed a unicast connection is likely to be in the vicinity, it is highly likely that a connection establishment process can be performed without performing the opposing UE detection phase. Therefore, there is a high possibility that the opposing UE detection phase can be omitted, and signaling between UEs can be reduced. Since there are cases where other UEs can use resources for the opposing UE detection phase, resource usage efficiency can be improved.

[0657] Figure 32 is a fourth example of a sequence for unicast communication between two UEs for SL unicast. In Figure 32, the same step numbers are used for steps common to Figures 29 and 31, and common explanations are omitted. In the example of Figure 32, a UE to be a target first transmits a signal / channel to indicate its presence. A UE that has generated transmission data in SL receives a signal / channel to indicate its presence transmitted from another UE and detects the target UE.

[0658] In Step ST5401, UE_B performs resource sensing, resource selection, and resource reservation for transmitting a signal / channel to indicate its presence. In Step ST5402, UE_B transmits a signal / channel to indicate its presence. The signal / channel may be transmitted by broadcast. The method of transmitting the signal / channel to indicate its presence may be the same as the method of transmitting the signal / channel to indicate its intention to transmit described above. As a stop condition, a connection request may be used instead of the signal / channel to indicate its presence.

[0659] In step ST5101, UE_A, which has generated transmission data in SL, receives a signal / channel indicating the presence transmitted from other UE (step ST5402) and detects a target UE (step ST5106). In step ST5301, UE_A performs resource sensing, resource selection, and resource reservation for transmitting a connection request and / or for responding to the connection request, and transmits a connection request signaling in step ST5107.

[0660] In this way, a UE that has data to transmit in SL does not need to transmit a signal / channel to indicate its intention to transmit, which reduces the delay time from the generation of data to be transmitted in SL to the connection establishment phase.

[0661] A UE in a state where SL communication is not possible may not transmit a signal / channel for indicating its presence. A UE in a state where unicast communication or unicast connection is not possible may not transmit a signal / channel for indicating its presence. A UE in a state where SL communication is not possible is, for example, a UE that does not have the capability of SL communication. In addition, for example, when the allowable communication processing load in the UE is exceeded, the UE is in a state where SL communication is not possible. In this way, it is possible to limit UEs that transmit a signal / channel for indicating their presence. Signals / channels or signaling between UEs can be reduced. The amount of resources used for signals / channels or signaling between UEs can be reduced.

[0662] Fig. 33 is a fifth example of a sequence up to unicast communication between two UEs for SL unicast. In Fig. 33, steps common to Fig. 29 and Fig. 30 are given the same step numbers, and common explanations are omitted. In the example of Fig. 33, a UE to be a target first transmits a connection request signaling. A UE that has data to transmit in SL receives a connection request signaling transmitted from another UE and detects the target UE. Fig. 33 is an example in which the transmission of a signal / channel to indicate the presence is reduced compared to Fig. 32. It is preferable to transmit a connection request instead of transmitting a signal / channel to indicate the presence.

[0663] In Step ST5501, UE_B performs resource sensing, resource selection, and resource reservation for transmitting a connection request signaling. In Step ST5201, UE_B transmits a signal / channel for indicating a connection request. The signal / channel may be transmitted by broadcast. The information to be included in the signal / channel for indicating a connection request may include information such as SR and BSR in addition to information to be included in the signal / channel for indicating presence. When there is data to be transmitted from UE_B to UE_A, it is preferable to transmit SR, BSR, etc. by including them in the signal / channel for indicating a connection request. Also, instead of information indicating presence, information indicating that it is a connection request may be included in the signal / channel for indicating a connection request.

[0664] The method of transmitting the connection request signaling may be the same as the above-mentioned method of transmitting the signal / channel for indicating the intention to transmit, and the stopping condition may be the resource scheduling for data transmission instead of the signal / channel for indicating the presence.

[0665] In step ST5101, UE_A, which has data to transmit in SL, receives connection request signaling transmitted from other UEs (step ST5201) and detects a target UE. In step ST5109, UE_A performs resource sensing, resource selection, and resource reservation for data transmission resource scheduling and / or unicast communication, and transmits data transmission scheduling in step ST5110.

[0666] In this way, a UE that has data to transmit in SL does not need to transmit a signal / channel to indicate its intention to transmit. It also does not need to transmit a signal / channel to indicate its presence before a connection request. This makes it possible to reduce the delay time from the generation of data to transmit in SL to the data transmission phase.

[0667] Figure 34 is a sixth example of a sequence for unicast communication between two UEs for SL unicast. In Figure 34, the same step numbers are used for steps common to Figures 29 and 32, and common explanations are omitted. In the example of Figure 34, a UE to be a target first transmits a signal / channel to indicate its presence. A UE that has generated transmission data in SL receives a signal / channel to indicate its presence transmitted from another UE, and detects the target UE.

[0668] In addition, the example of Fig. 34 omits the connection establishment phase compared to the example of Fig. 32. A UE that has data to transmit in SL transmits a data transmission schedule after detecting a target UE. A UE that has data to transmit in SL performs processing of the data transmission phase after detecting a target UE.

[0669] In Step ST5401, UE_B performs resource sensing, resource selection, and resource reservation for transmitting a signal / channel to indicate its presence. In Step ST5402, UE_B transmits a signal / channel to indicate its presence. The signal / channel may be transmitted by broadcast. The method of transmitting the signal / channel to indicate its presence may be the same as the method of transmitting the signal / channel to indicate the intention to transmit described above. As a stop condition, scheduling for data transmission may be used instead of the signal / channel to indicate its presence.

[0670] In step ST5101, UE_A, which has generated transmission data in SL, receives a signal / channel indicating the presence transmitted from other UE (step ST5402) and detects the target UE (step ST5106). In step ST5109, UE_A performs resource sensing, resource selection, and resource reservation for resources for data transmission scheduling and resources for unicast communication, and transmits a data transmission scheduling in step ST5110.

[0671] In this way, it is possible to omit the connection establishment phase, and therefore it is possible to reduce the delay time from when transmission data is generated in SL until the data transmission phase.

[0672] Fig. 35 is a seventh example of a sequence up to unicast communication between two UEs for SL unicast. In Fig. 35, steps common to Fig. 29 are given the same step numbers, and common explanations are omitted. In the example of Fig. 35, a UE that has data to transmit in SL transmits a schedule for data transmission. Compared to Fig. 29, Fig. 35 is an example in which the process from a signal / channel for indicating an intention to transmit to a response to a connection request is omitted. Fig. 35 is also an example in which the opposing UE detection phase and the connection establishment phase are omitted. In the data transmission phase, opposing UE detection is also performed. This is more suitable for a case where one UE is a target UE than a case where multiple UEs are target UEs.

[0673] In step ST5101, UE_A, which has generated data to transmit in SL, performs resource sensing, resource selection, and resource reservation of resources for data transmission scheduling and unicast communication in step ST5109, and transmits the data transmission scheduling in step ST5701. The data transmission scheduling may be transmitted by broadcast. In step ST5111, UE_B detects a PSCCH that includes scheduling information for data transmission addressed to its own UE. In step ST5112, UE_B receives data from UE_A in accordance with the data transmission scheduling information included in the detected PSCCH.

[0674] In step ST5112, UE_B may transmit HARQ feedback, CSI report, and / or data for the data received from UE_A to UE_A.

[0675] In this way, it is possible to omit the opposed UE detection phase and the connection establishment phase, thereby reducing the delay time from the generation of transmission data in SL to the data transmission phase.

[0676] The UE may store a UE that has performed unicast communication once. The UE may store a UE that has performed unicast communication once for a predetermined period of time. The UE may perform connection processing preferentially for a UE that has performed unicast communication once. In such a case, the opposing UE detection phase and the connection establishment phase may be omitted. UE_A may transmit resource scheduling for data transmission, and perform the opposing UE detection phase or the connection establishment phase when feedback cannot be received. Since a UE that has performed unicast communication once is likely to be in the vicinity, it is highly likely that the connection establishment processing can be performed without performing the opposing UE detection phase and / or the connection establishment phase. Therefore, it is highly likely that the opposing UE detection phase and the connection establishment phase can be omitted, and signaling between UEs can be reduced. Since there are cases where other UEs can use resources for the opposing UE detection phase and the connection establishment phase, resource usage efficiency can be improved.

[0677] In the data transmission phase, the initial or retransmitted data transmission may be performed by broadcast communication, and feedback, reports, etc. may be performed by unicast communication. In the case where the target UE cannot be detected at the time of data transmission, the initial or retransmitted data transmission m...

Claims

1. A plurality of user equipments capable of communicating with each other in a side link; A user device in a communication system including a base station that wirelessly communicates with each of the plurality of user devices, performing a unicast transmission on the sidelink; Sending a Scheduling Request (SR) or a Buffer Status Report (BSR) to the base station; receiving a resource configuration transmitted from the base station based on the SR or the BSR; User equipment.

2. A plurality of user equipments capable of communicating with each other in a side link; A base station in a communication system comprising: a base station that wirelessly communicates with each of a plurality of user devices; The user equipment performs a unicast transmission on the sidelink; receiving a Scheduling Request (SR) or a Buffer Status Report (BSR) from the user equipment; sending a resource configuration to the user equipment based on the SR or the BSR; Base station.

3. A plurality of user equipments capable of communicating with each other in a side link; A communication system comprising: a base station that wirelessly communicates with each of a plurality of user devices; A user device performing a unicast transmission on the sidelink; Sending a Scheduling Request (SR) or a Buffer Status Report (BSR) to the base station; receiving a resource configuration transmitted from the base station based on the SR or the BSR; Communication systems.

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