Terminal device, base station device, control method of terminal device, and control method of base station device

Abstract

A terminal device includes a communication unit and a control unit. The control unit is configured to: receive disabling information of hybrid automatic repeat request (HARQ) feedback through the communication unit, and identify that one or more HARQ feedbacks indicated by the disabling information of the HARQ feedback are disabled, and the disabling information of the HARQ feedback is set for each cell, each beam, each component carrier, each bandwidth part (BWP), each user equipment (UE) or each HARQ process.

Description

Technical Field

[0001] Embodiments of the present invention relate to a terminal device, a base station device, a method for controlling a terminal device, and a method for controlling a base station device. Background Art

[0002] In 3rd Generation Partnership Project (3GPP) Rel.15 New Radio (NR), Hybrid Automatic Repeat Request (HARQ) is supported similar to Long Term Evolution (LTE). In HARQ, error correction is performed by soft combining first-transmission data and retransmission data. As a result, coding gain can be obtained. This process is performed for each process called "HARQ process". That is, in the case of multiple (for example, 16) HARQ processes, it is possible to perform the HARQ processes in parallel.

[0003] Since various use cases are assumed in NR, the number of HARQ processes may be insufficient depending on the use cases. For example, in the case of low-latency processing and low-latency communication (e.g., ultra-reliable low-latency communication (URLLC)), there is a possibility that data is received continuously in a short period of time, and the number of HARQ processes may be insufficient due to untimely HARQ processing. In addition, in the case of non-terrestrial network (NTN) communication, a delay in HARQ processing occurs due to propagation delay, and the number of HARQ processes may be insufficient. Regarding the shortage of the number of HARQ processes, it is known to deactivate or disable HARQ feedback.

[0004] Reference List

[0005] Non-patent literature

[0006] Non-Patent Document 1: PR-190710, Revised SID for Research on Solutions for NR Supporting Non-Terrestrial Networks (NTN)

[0007] Non-Patent Document 2: R1-1906088, Nokia, Nokia Shanghai Bell, “Consideration on HARQ in NTN”, 3GPP TSG RAN1 Meeting #97, Reno, USA, May 2019 Summary of the invention

[0008] Technical issues

[0009] However, in the prior art described above, the specific method of HARQ feedback disabling has not been fully studied. The detailed configuration method of HARQ feedback disabling for the terminal device is unclear. Therefore, the shortage of the number of HARQ processes may not be solved, and the desired communication quality may not be obtained.

[0010] Therefore, an object of the present disclosure is to provide a terminal device, a base station device, a method for controlling the terminal device, and a method for controlling the base station device that contribute to obtaining desired communication quality.

[0011] Solutions to the Problem

[0012] In order to solve the above-described problem, a terminal device according to an embodiment of the present disclosure includes a communication unit and a control unit. The control unit is configured to receive disabling information of hybrid automatic repeat request (HARQ) feedback through the communication unit, and recognize that one or more HARQ feedbacks indicated by the disabling information of the HARQ feedback are disabled, and the disabling information of the HARQ feedback is set for each cell, each beam, each component carrier, each bandwidth part (BWP), each user equipment (UE) or each HARQ process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a diagram showing one configuration example of a communication system according to one embodiment of the present disclosure.

[0014] Figure 2 is a diagram showing one example of a wireless network provided by a communication system.

[0015] Figure 3 is a diagram showing an overview of satellite communications provided by a communication system.

[0016] Figure 4 is a diagram showing one example of a cell configured by satellite stations.

[0017] Figure 5 is a diagram showing a configuration example of a management device according to an embodiment of the present disclosure.

[0018] Figure 6 is a diagram showing one configuration example of a non-ground station according to one embodiment of the present disclosure.

[0019] Figure 7 is a diagram showing a configuration example of a terminal device according to an embodiment of the present disclosure.

[0020] Figure 8 is a flowchart showing one example of initial access processing.

[0021] Fig. 9 is a sequence diagram showing an example of the HARQ procedure.

[0022] Fig.10 is an explanatory diagram for describing the overview of the HARQ buffer.

[0023] Fig.11 is a sequence diagram showing an example of HARQ disabling processing according to an embodiment of the present disclosure.

[0024] Fig.12 is a sequence diagram showing an example of HARQ disabling processing according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In each of the following embodiments, the same parts are marked with the same reference numerals, and thus repeated description will be omitted.

[0026] In this specification and the drawings, multiple components having substantially the same functional configuration can be distinguished by appending different numbers after the same reference numerals. For example, multiple configurations having substantially the same functional configuration can be distinguished as terminal devices 501, 502, and 503 when necessary. However, in the case where it is not particularly necessary to distinguish each of the multiple components having substantially the same functional configuration, only the same reference numeral is appended. For example, in the case where it is not particularly necessary to distinguish terminal devices 501, 502, and 503, they are simply referred to as terminal device 50.

[0027] The present disclosure will be described in the order of items shown below.

[0028] 1. Introduction

[0029] 2. Example

[0030] 2-1. Overall configuration of the communication system

[0031] 2-2. Configuration of management equipment

[0032] 2-3. Base station configuration

[0033] 2-4. Configuration of relay stations

[0034] 2-5. Configuration of terminal equipment

[0035] 2-6. Initial access processing

[0036] 2-7. Example of HARQ Procedure

[0037] 2-8. Propagation delay problem

[0038] 2-9. Overview of Embodiments

[0039] 2-10. Example of HARQ Disable Processing (Downlink)

[0040] 2-11. Example of HARQ disabling processing (uplink)

[0041] 2-12. Support HARQ disabled feature compensation

[0042] 3. Modification

[0043] 3-1. Modifications in the case where the number of HARQ processes can be increased

[0044] 3-2. Other changes

[0045] 4. Conclusion

[0046] <1. Introduction>

[0047] Radio access technologies such as LTE and NR are studied in 3GPP. LTE and NR are types of cellular communication technologies, and mobile communication of terminal devices is achieved by arranging multiple areas covered by base stations in a honeycomb shape. In the following description, it is assumed that "LTE" includes Advanced LTE (LTE-A), Professional Advanced LTE (LTE-A Pro), and Evolved Universal Terrestrial Radio Access (EUTRA). In addition, it is assumed that NR includes New Radio Access Technology (NRAT) and Future EUTRA (FEUTRA).

[0048] NR is the next (fifth) generation radio access technology (RAT) to LTE. NR is a radio access technology that can support multiple use cases, including enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and URLLC. NR is studied for the technical framework to support the use cases, requirements, and arrangements in these use cases.

[0049] For example, with the increasing demand for large-area coverage, connection stability, etc., research on non-terrestrial networks (NTNs) has begun as a use case for NR. In non-terrestrial networks, wireless networks are scheduled to be provided to terminal devices through other base stations other than ground stations, such as satellite stations or aircraft stations. Other base stations other than ground stations are called non-ground stations or non-ground base stations. The wireless network provided by the ground station is called a terrestrial network (TN). By using the same radio access scheme for terrestrial networks and non-terrestrial networks, integrated operation of terrestrial networks and non-terrestrial networks becomes possible.

[0050] In the embodiments of the present disclosure, a ground station (also referred to as a ground base station) refers to a base station (including a relay station) installed on the ground. "Ground" is a broad term that includes not only the ground (land), but also underground, above water, and underwater.

[0051] In some embodiments, an application example for NTN will be described as a use case of NR. However, the application destinations of these embodiments are not limited to NTN, and can be applied to other technologies and use cases (such as URLLC).

[0052] <2. Embodiment>

[0053] The communication system 1 according to the present embodiment will be described below. The communication system 1 includes a non-terrestrial station and uses a non-terrestrial network to provide radio communication for a terminal device. In addition, the communication system 1 can be capable of providing radio communication with a terrestrial network. The non-terrestrial network and the terrestrial network included in the communication system 1 are not limited to wireless networks using a radio access scheme defined by NR. The non-terrestrial network included in the communication system 1 can be a wireless network of a radio access scheme other than NR, such as LTE, wideband code division multiple access (W-CDMA) or code division multiple access 2000 (cdma2000).

[0054] In the following description, the concept of a base station (hereinafter also referred to as a base station device) may include a relay station (hereinafter also referred to as a relay device (relay node)) and a donor base station that provides a wireless interface to the relay station. In addition, the concept of a base station includes not only a structure having the function of a base station, but also a device installed in the structure. The structure is, for example, a building, such as a high-rise building, a house, a steel tower, a station facility, an airport facility, a port facility, or a stadium. The concept of a structure includes not only a building, but also a structure (non-building structure) such as a tunnel, a bridge, a dam, a wall, or an iron column, and equipment such as a crane, a gate, or a windmill. In addition, the concept of a structure includes not only structures on or under the ground (land), but also structures on the water such as a platform or a super-large floating body, and underwater structures such as an ocean observation facility. In addition, a base station can be configured by a collection including multiple physical or logical devices. For example, in an embodiment of the present disclosure, a base station can be distinguished into multiple devices of a baseband unit (BBU) and a radio unit (RU), and can be interpreted as an assembly of the multiple devices. Additionally or alternatively, in an embodiment of the present disclosure, the base station may be any one or both of the BBU and the RU. The BBU and the RU may be connected via a predetermined interface (e.g., eCPRI). Additionally or alternatively, the RU may be referred to as a remote radio unit (RRU) or a radio DoT (RD). Additionally or alternatively, the RU may correspond to the gNB-DU described later. Additionally or alternatively, the BBU may correspond to the gNB-CU described later. Additionally or alternatively, the RU may be a device integrated with an antenna. The antenna included in the base station (e.g., an antenna integrated with the RU) may adopt an advanced antenna system and support MIMO (e.g., FD-MIMO) or beamforming. In an advanced antenna system, the antenna included in the base station (e.g., an antenna integrated with the RU) may, for example, include 64 transmit antenna ports and 64 receive antenna ports.

[0055] The base station may be a base station configured to be movable. For example, the base station may be a device installed in a mobile subject, or may be the mobile subject itself. The mobile subject may be a mobile subject such as a smart phone, a mobile subject moving on the ground (land) (for example, a vehicle such as a car, a bus, a truck, a train or a linear electric locomotive), or a mobile subject moving underground (for example, in a tunnel) (for example, a subway). In addition, the mobile subject may be a mobile subject moving on water (for example, a ship such as a passenger ship, a cargo ship or an air cushion craft), or a mobile subject moving underwater (for example, a submersible and an unmanned submersible). In addition, the mobile subject may be a mobile subject moving within the atmosphere (for example, an aircraft such as an airplane, an airship or a drone), or a space mobile subject moving outside the atmosphere (for example, an artificial subject such as an artificial satellite, a spacecraft, a space station and a probe).

[0056] A plurality of base stations may be connected to each other. One or more base stations may be included in a radio access network (RAN). That is, a base station may be simply referred to as a RAN, a RAN node, an access network (AN), or an AN node. The RAN in LTE is referred to as an enhanced universal terrestrial RAN (EUTRAN). The RAN in NR is referred to as NGRAN. The RAN in W-CDMA (UMTS) is referred to as UTRAN. The base station of LTE is referred to as an evolved Node B (eNodeB) or eNB. That is, the EUTRAN includes one or more eNodeBs (eNBs). The NR base station is referred to as a gNodeB or gNB. That is, the NGRAN includes one or more gNBs. In addition, the EUTRAN may include a gNB (en-gNB) connected to a core network (EPC) in an LTE communication system (EPS). Similarly, the NGRAN may include an ng-eNB connected to a core network 5GC in a 5G communication system (5GS). Additionally or alternatively, when a base station is an eNB, a gNB, or the like, the base station may be referred to as a 3GPP access. Additionally or alternatively, when the base station is a radio access point (access point), the base station may be referred to as a non-3GPP access. Additionally or alternatively, the base station may be referred to as a remote radio head (RRH) optical extension device. Additionally or alternatively, when the base station is a gNB, the base station may be referred to as a combination of or any one of the gNB CU (central unit) and gNB DU (distributed unit) described above. The gNB central unit (CU) hosts multiple higher layers (e.g., RRC, SDAP, PDCP) of the access layer for communication with the UE. On the other hand, the gNB-DU hosts multiple lower layers (e.g., RLC, MAC, PHY) of the access layer. That is, among the message information to be described later, RRC signaling (semi-static notification) may be generated by the gNB CU, and DCI (dynamic notification) may be generated by the gNB-DU. Additionally or alternatively, in the RRC configuration (semi-static notification), some configurations such as IE: cellGroupConfig may be generated by the gNB-DU, and the rest of the configurations may be generated by the gNB-CU. These configurations can be sent and received via the F1 interface to be described later. The base station can be configured to communicate with other base stations. For example, when the multiple base stations are eNBs or a combination of eNBs and en-gNBs, the base stations can be connected via the X2 interface. Additionally or alternatively, when the multiple base stations are gNBs or a combination of gn-eNBs and gNBs, the devices can be connected via the Xn interface. Additionally or alternatively, when the multiple base stations are a combination of gNB central units (CUs) and gNB distributed units (DUs), the devices can be connected via the F1 interface described above.Messages and information (RRC signaling or DCI information) to be described later may be transmitted between multiple base stations (eg, via X2, Xn, F1 interfaces).

[0057] In LTE and NR, a terminal device (also referred to as a mobile station, a mobile station device, or a terminal) may be referred to as a user equipment (UE). Alternatively, a terminal device may be referred to as a mobile station (MS) or a wireless transmit receive unit (WTRU). A terminal device is a type of radio communication device and is also referred to as a mobile station, a mobile station device, or a terminal. In the embodiments of the present disclosure, for example, the concept of a terminal device includes not only a portable terminal device such as a mobile terminal, but also a device installed in a structure or a mobile body.

[0058] <2-1. Overall configuration of the communication system>

[0059] Figure 1 1 is a diagram showing a configuration example of a communication system 1 according to an embodiment of the present disclosure. The communication system 1 includes a management device 10, a non-terrestrial base station (hereinafter referred to as a base station) 20, a terrestrial base station (hereinafter referred to as a base station) 30, a relay device (hereinafter referred to as a base station) 40, and a terminal device 50. The communication system 1 provides a user with a wireless network capable of mobile communication through the radio communication devices constituting the communication system 1 that operate in cooperation. The radio communication device is a device having a radio communication function and corresponds to Figure 1 Base stations 20, 30, 40 and terminal device 50 in the example.

[0060] The communication system 1 may include a plurality of management devices 10, a plurality of base stations 20, 30, 40 and a plurality of terminal devices 50. Figure 1 In the example of , the communication system 1 includes management devices 101, 102, etc. as the management device 10. The communication system 1 includes base stations 201, 202, etc. as the base station 20, and includes base stations 301, 302, etc. as the base station 30. The communication system 1 includes base stations 401, 402, etc. as the base station 40, and includes terminal devices 501, 502, 503, etc. as the terminal device 50. As described above, the application destination of the embodiments of the present disclosure is not limited to non-terrestrial communications (NTN). That is, the communication system may not include a non-terrestrial station.

[0061] The management device 10 is a device for managing a wireless network. For example, the management device 10 is a device that acts as a mobile management entity (MME) or an access and mobility management function (AMF). The MME is connected to the EUTRAN via an S1 interface, controls the non-access stratum (NAS) signaling with the UE, and manages the mobility of the UE. The AMF is connected via the NGRAN and NG interfaces, controls the non-access stratum (NAS) signaling with the UE, and manages the mobility of the UE. The management device 10 may be included in the core network CN. The core network CN is, for example, an evolved packet core (EPC) or a 5G core network (5GC). The management device 10 is connected to each of a plurality of base stations 20 and a plurality of base stations 30. The management device 10 manages the communication between the base station 20 and the base station 30. In addition to control plane (C-plane) nodes such as the management device 10, the core network also transmits user data between a packet data network (PDN) or a data network (DN) and the RAN. A user plane (U-plane) node may also be included. The U-plane nodes in the EPC include a serving gateway (S-GW) or a PDN gateway (P-GW). The U-plane node in the 5GC may include a U-plane function (UPF). For example, for each terminal device 50 in an area unit (e.g., a tracking area, a RAN notification area) including multiple cells, the management device 10 manages the location of the terminal device 50 (UE) in the communication system 1. For each terminal device 50 in the cell unit, the management device 10 can grasp and manage the base station (or cell) to which the terminal device belongs, the base station (or cell) in whose communication area the terminal device 50 exists, and so on.

[0062] The base station 20 is a base station for wireless communication with the terminal device 50. Figure 1 In the example of FIG. 4 , the base station 201 is connected to the base station 401, and can also wirelessly communicate with the terminal device 50 through the base station 401. In this embodiment, the base station 20 is a base station capable of floating in the air or space. For example, the base station 20 is a non-ground station device such as an aircraft station or a satellite station.

[0063] An aircraft station is, for example, a radio communication device capable of floating in the atmosphere, such as an aircraft. An aircraft station may be, for example, a device mounted on an aircraft or the like, or may be the aircraft itself. The concept of an aircraft includes not only heavy aircraft such as airplanes and gliders, but also light aircraft such as balloons and airships. In addition, the concept of an aircraft includes not only heavy aircraft and light aircraft, but also rotorcraft such as helicopters and autogyroplanes. An aircraft station (or an aircraft on which an aircraft station is mounted) may be an unmanned aircraft such as a drone. The concept of an unmanned aircraft also includes an unmanned aircraft system (UAS) and a tethered UAS. The concept of an unmanned aircraft also includes a lighter-than-air UAS (LTA) and a heavier-than-air UAS (HTA). Other concepts of unmanned aircraft also include a high altitude UAS platform (HAP). When an aircraft station acts as a UE, the aircraft station may be a flying UE.

[0064] A satellite station is a radio communication device capable of floating outside the atmosphere. A satellite station may be a device installed on a spacecraft such as an artificial satellite, or may be the spacecraft itself. A satellite acting as a satellite station may be any one of a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, a geostationary earth orbit (GEO) satellite, and a high elliptical orbit (HEO) satellite. Of course, a satellite station may be a device installed on a low earth orbit satellite, a medium earth orbit satellite, a geostationary earth orbit satellite, or a high elliptical orbit satellite.

[0065] The base station 30 is a base station for wireless communication with the terminal device 50. Figure 1 In the example of FIG. 3 , the base station 301 is connected to the base station 402, and can also communicate wirelessly with the terminal device 50 through the base station 402. The base station 30 may be a base station arranged in a structure on the ground, or may be a base station installed in a mobile body moving on the ground. For example, the base station 30 is an antenna installed in a structure such as a building and a signal processing device connected to the antenna. Of course, the base station 30 may be a structure or a mobile body itself.

[0066] The base station 40 is a device that acts as a relay station of the base station. The base station 40 is a type of base station. The base station 40 relays the communication between the base station 20 and the terminal device 50 or the communication between the base station 30 and the terminal device 50. The base station 40 may be a ground station or a non-ground station. The base station 40 may constitute a radio access network RAN ​​together with the base station 20 and the base station 30.

[0067] The terminal device 50 is, for example, a mobile phone, a smart device (smart phone or tablet device), a personal digital assistant (PDA) or a personal computer. In addition, the terminal device 50 can be a machine-to-machine (M2M) device or an Internet of Things (IoT) device (for example, it can be called an MTC UE, a NB-IoT UE or a Cat.M UE). In addition, the terminal device 50 can be a radio communication device installed in a mobile body, or it can be the mobile body itself. It should be noted that the terminal device 50 can be a relay station for relaying satellite communications, or it can be a base station for receiving satellite communications. The terminal device 50 supports both terrestrial networks and non-terrestrial networks. Therefore, the terminal device 50 can communicate not only with ground station devices such as the base station 30, but also with non-ground station devices such as the base station 20.

[0068] Figure 2is a diagram showing an example of a wireless network provided by a communication system 1. Each of the base station 20 and the base station 30 constitutes a cell. A cell is an area in which radio communication is covered by a base station. The cell constituted by the base station 20 and the base station 30 may be any one of a macrocell, a microcell, a femtocell, and a small cell. The communication system 1 may be configured to manage multiple cells by a single base station, or may be configured to manage one cell by multiple base stations. The cell provided by the base station is referred to as a service cell. The service cell includes a primary cell (PCell) and a secondary cell (SCell). In the case of providing a dual connection (e.g., EUTRA-EUTRA dual connection, EUTRA-NR dual connection (ENDC), EUTRA-NR dual connection with 5GC, NR-EUTRA dual connection (NEDC), NR-NR dual connection) to a UE (e.g., a terminal device 50), the PCell provided by the dominant node (MN) and zero or one or more SCells are referred to as a dominant cell group. The service cell may include a primary secondary cell or a primary SCG cell (PSCell). That is, in the case of providing dual connectivity to the UE, the PSCell and zero or one or more SCells provided by the secondary node (SN) are referred to as a secondary cell group (SCG). Unless otherwise configured (e.g., PUCCH on the SCell), the physical uplink control channel (PUCCH) is sent in the PCell and PSCell, but not in the SCell. In addition, radio link failures are detected in the PCell and PSCell, but not in the SCell (may not be detected). As described above, since the PCell and PSCell have special roles in (multiple) serving cells, they are also referred to as special cells (SpCell). One downlink component carrier and one uplink component carrier can be associated with one cell. The system bandwidth corresponding to one cell can be divided into multiple bandwidth parts. In this case, one or more bandwidth parts can be configured for the UE, and one bandwidth part can be used for the UE as an active BWP. The radio resources (e.g., frequency band, parameter set (subcarrier spacing) and time slot format (time slot configuration)) that can be used by the terminal device 50 can be different for each cell, each component carrier or each BWP.

[0069] exist Figure 2In the example of FIG. 1 , base stations 301 and 302 constitute a land network TN1, and base stations 303, 304, and 305 constitute a land network TN2. The land network TN1 and the land network TN2 are, for example, land networks operated by a radio communication operator (mobile network operator (MNO)) such as a telephone company. The land network TN1 and the land network TN2 may be operated by different radio communication operators (i.e., MNOs with different PLMNs), or may be operated by the same radio communication operator. The land network TN1 and the land network TN2 may be regarded as one land network.

[0070] Land network TN1 and land network TN2 are connected to the core network respectively. Figure 2 In the example of , the base station 30 constituting the land network TN2 is connected to the core network CN constituted by the management device 101 and the like. If the radio access scheme of the land network TN2 is LTE, the core network CN is EPC. When the radio access scheme of the land network TN2 is NR, the core network CN is 5GC. Of course, the core network CN is not limited to EPC or 5GC, and may be a core network of another radio access scheme. Figure 2 In the example of FIG. 1 , the land network TN1 is not connected to the core network, but the land network TN1 may be connected to the core network CN. The land network TN1 may be connected to a core network (not shown) different from the core network CN.

[0071] The core network CN includes a gateway device, a gateway switch, etc., and is connected to a public network PN through the gateway device. The public network PN is, for example, a public data network such as the Internet, a regional IP network, or a telephone network (a mobile phone network, a fixed telephone network, etc.). The gateway device is, for example, a server device connected to the Internet, a regional IP network, etc. The gateway switch is, for example, a switch connected to the telephone network of a telephone company. The management device 101 may have a function as a gateway device or a gateway switch.

[0072] Figure 2 Each of the base stations 20 and 40 shown in FIG. 1 is a non-ground station device such as a satellite station or an aircraft station. A group of satellite stations (or a single satellite station) constituting a non-terrestrial network is called a space platform. A group of aircraft stations (or a single aircraft station) constituting a non-terrestrial network is called an airborne platform. Figure 2 In the example of FIG. 4 , base station 202, base station 401 and base station 402 constitute space platform SBP1, and base station 201 constitutes space platform SBP2. Base station 203 configures air platform ABP1.

[0073] Terminal device 50 can communicate with both base station 30 and base station 20. Figure 2In the example of FIG. 5 , the terminal device 501 can communicate with the base station 30 constituting the terrestrial network TN1. The terminal device 501 can communicate with the base stations 20 constituting the space platforms SBP1 and SBP2. The terminal device 501 can also communicate with the base station 20 constituting the aerial platform ABP1. The terminal device 501 can communicate with another terminal device 50 (in Figure 2 In the example, terminal device 502) communicates directly.

[0074] The base stations 20 are connected to a terrestrial network or a core network through a relay station 60. The base stations 20 constituting the space platforms SBP1, SBP2 are connected to the terrestrial network TN1 through a relay station 601. The base stations 20 constituting the space platforms SBP1, SBP2 and the air platform ABP1 are connected to the core network CN through a relay station 602. The base stations 20 can communicate directly with each other without the relay station 60.

[0075] The relay station 60 is, for example, an aircraft station or an earth station. The aircraft station is a wireless station installed on the ground or on a mobile body moving on the ground to communicate with the aircraft station. The earth station is a wireless station located on the earth (including the air) to communicate with a satellite station (space station). The earth station may be a large earth station or a small earth station such as a very small aperture terminal (VSAT). The earth station may be a VSAT-controlled earth station (also referred to as a master station or a HUB station), or a VSAT earth station (also referred to as a slave station). The earth station may be a wireless station installed in a mobile body moving on the ground. For example, there is a shipborne earth station (ESV) as an earth station installed on a ship. The earth station may include an aircraft earth station installed in an aircraft (including a helicopter) and communicating with a satellite station. The earth station may include an aeronautical earth station installed on a mobile body moving on the ground and communicating with the aircraft earth station through a satellite station. The relay station 60 may be a portable and movable wireless station that communicates with a satellite station or an aircraft station. The relay station 60 may be considered as a part of the communication system 1 .

[0076] Each device constituting the space platform SBP1, SBP2 performs satellite communication with the terminal device 50. The satellite communication is radio communication between a satellite station and the terminal device 50. Figure 3 is a diagram showing an overview of satellite communications provided by the communication system 1. Satellite stations are mainly divided into geostationary earth orbit satellite stations and low earth orbit satellite stations.

[0077] Geostationary Earth orbit satellite stations are located at an altitude of approximately 35,786 km and orbit the Earth at the same speed as the Earth's rotation. Figure 3In the example of FIG. 1 , the base station 201 constituting the space platform SBP2 is a geostationary earth orbit satellite station. The relative speed between the geostationary earth orbit satellite station and the terminal device 50 on the ground is substantially 0, and the station appears to be stationary when observed from the terminal device 50 on the ground. The base station 201 implements satellite communication with the terminal devices 501, 503, 504, etc. located on the earth.

[0078] A low earth orbit satellite station is a satellite station whose orbit is at a lower altitude than a geostationary earth orbit satellite station or a medium earth orbit satellite station. A low earth orbit satellite station is, for example, a satellite station located at an altitude of 500km to 2000km. Figure 3 In the example of FIG. 1 , base stations 202 and 203 constituting space platform SBP1 are low earth orbit satellite stations. As satellite stations constituting space platform SBP1, Figure 3 Only two base stations 202 and 203 are shown. However, in reality, among the satellite stations constituting the space platform SBP1, the low earth orbit satellite constellation is formed by two or more (e.g., tens to thousands) base stations 20. Unlike the geostationary earth orbit satellite station, the low earth orbit satellite station has a relative speed with the terminal equipment 50 on the ground, and appears to be moving when observed from the terminal equipment 50 on the ground. Each of the base stations 202 and 203 constitutes a cell, and implements satellite communication with the terminal equipment 501, 502, 503, etc. located on the earth.

[0079] Figure 4 is a diagram showing one example of a cell configured by satellite stations. Figure 4 The cell C2 formed by the base station 203 which is a low earth orbit satellite station is shown. The satellite station in the low orbit communicates with the terminal device 50 on the ground with a predetermined directivity on the ground. For example, Figure 4 The angle R1 shown in FIG. is 40°. Figure 4 In the case of, the radius D1 of the cell C2 formed by the base station 203 is, for example, 1000 km. The low earth orbit satellite station moves at a constant speed. When it becomes difficult for a low earth orbit satellite station to provide satellite communication to the terminal device 50 on the ground, the subsequent low earth orbit satellite station provides satellite communication. Figure 4 In the case of the example, when it becomes difficult for the base station 203 to provide satellite communication to the terminal device 50 on the ground, the subsequent base station 204 provides satellite communication. The values ​​of the angle R1 and the radius D1 described above are merely examples and are not limited to the foregoing values.

[0080] As described above, the terminal device 50 can implement radio communication using a non-terrestrial network. The base station 20 and the base station 40 of the communication system 1 constitute a non-terrestrial network. As a result, the communication system 1 can extend services to the terminal device 50 located in an area that cannot be covered by the terrestrial network. For example, the communication system 1 can provide public safety communications and critical communications to the terminal device 50 such as an Internet of Things (IoT) device or a machine type communication (MTC) device. Since the use of the non-terrestrial network improves service reliability and recoverability, the communication system 1 can reduce the vulnerability of the service to physical attacks or natural disasters. The communication system 1 can realize service connections to aircraft terminal devices such as airplane passengers and drones, and service connections to mobile terminal devices such as ships and trains. The communication system 1 can realize the provision of A / V content, group communication, IoT broadcast services, software download services, high-efficiency multicast services such as emergency messages, high-efficiency broadcast services, etc. The communication system 1 can also realize the unloading of traffic between the terrestrial network and the non-terrestrial network. To achieve this, in operation, it is desirable to integrate the non-terrestrial network provided by the communication system 1 and the terrestrial network provided by the communication system 1 in a higher layer, but the present invention is not limited thereto. It is desirable that the non-terrestrial network provided by the communication system 1 and the terrestrial network provided by the communication system 1 have a common radio access system, but the present invention is not limited thereto.

[0081] Next, the configuration of each device constituting the communication system 1 according to the present embodiment will be described in detail.

[0082] <2-2. Configuration of management equipment>

[0083] The management device 10 is a device for managing a wireless network. For example, the management device 10 is a device for managing communications between the base station 20 and the base station 30. When the core network is EPC, the management device 10 is, for example, a device having a function as a mobile management entity (MME). When the core network is 5GC, the management device 10 is, for example, a device having a function as an access and mobility management function (AMF). The management device 10 may have the function of a gateway. For example, when the core network is EPC, the management device 10 may have a function as a serving gateway (S-GW) or a packet data network gateway (P-GW). When the core network is 5GC, the management device 10 may have a function as a user plane function (UPF). The management device 10 is not necessarily a device constituting a core network. For example, when the core network is a core network of W-CDMA or cdma 2000, the management device 10 may be a device acting as a radio network controller (RNC).

[0084] Figure 51 is a diagram showing one configuration example of the management device 10 according to one embodiment of the present disclosure. The management device 10 includes a communication unit 11 , a storage unit 12 , and a control unit 13 . Figure 5 The configuration shown in FIG. 1 is a functional configuration, and the hardware configuration may be different from the functional configuration. The functions of the management device 10 may be implemented in a plurality of physically separated configurations in a distributed manner. For example, the management device 10 may include a plurality of server devices.

[0085] The communication unit 11 is a communication interface for communicating with other devices. The communication unit 11 may be a network interface or a device connection interface. For example, the network communication unit 11 may be a local area network (LAN) interface such as a network interface card (NIC), or may be a USB interface including a universal serial bus (USB) host controller, a USB port, etc. The communication unit 11 may be a wired interface or a wireless interface. The communication unit 11 serves as a communication device for the management device 10. The communication unit 11 communicates with the base station 30 and the relay station 60 under the control of the control unit 13.

[0086] The storage unit 12 is a data readable and writable storage device, such as a dynamic random access memory (DRAM), a static random access memory (SRAM), a flash memory, or a hard disk. The storage unit 12 acts as a storage device of the management device 10. The storage unit 12, for example, stores the connection state of the terminal device 50. For example, the storage unit 12 stores the radio resource control (RRC) state and the EPS connection management (ECM) state of the terminal device 50. The storage unit 12 can act as a home memory that stores the location information of the terminal device 50.

[0087] The control unit 13 is a controller that controls each unit of the management device 10. The control unit 13 is implemented by a processor such as a central processing unit (CPU) or a microprocessing unit (MPU), for example. For example, the control unit 13 is implemented by the processor using a random access memory (RAM) or the like as a work area to execute various programs stored in a storage device inside the management device 10. The control unit 13 can be implemented by an integrated circuit such as an application-specific integrated circuit (ASIC) or a field programmable gate array (FPGA). Any of the CPU, MPU, ASIC, and FPGA can be regarded as a controller.

[0088] <2-3. Base station configuration>

[0089] Next, the configuration of the base station will be described. As base stations, the communication system 1 includes a base station 20, a base station 30, and a base station 40. All base stations 20 to 40 may be movable. Hereinafter, the configuration of the base station 20 will be described as the configuration of the base station. The configurations of the base stations 30 and 40 may be the same as the configuration of the base station 20 described below.

[0090] Figure 6 2 is a diagram showing one configuration example of the base station 20 according to one embodiment of the present disclosure. The base station 20 includes a radio communication unit 21 , a storage unit 22 , and a control unit 23 . Figure 6 The configuration shown in FIG. 1 is a functional configuration, and the hardware configuration may be different from the functional configuration. The functions of the base station 20 may be implemented in a plurality of physically separated configurations in a distributed manner.

[0091] The radio communication unit 21 is a radio communication interface for implementing radio communication with other radio terminal devices (e.g., terminal device 50 or relay station 60). The radio communication unit 21 supports one or more radio access methods. For example, the radio communication unit 21 supports both NR and LTE. In addition to NR or LTE, the radio communication unit 21 can support W-CDMA or cdma 2000. The radio communication unit 21 includes a receiving processing unit 211, a sending processing unit 212, and an antenna 213. The radio communication unit 21 may include a plurality of receiving processing units 211, a plurality of sending processing units 212, and a plurality of antennas 213. When the radio communication unit 21 supports a plurality of radio access methods, each unit of the radio communication unit 21 may be configured separately for each radio access method. For example, the receiving processing unit 211 and the sending processing unit 212 may be configured separately by LTE and NR.

[0092] The reception processing unit 211 processes an uplink signal received through the antenna 213. The reception processing unit 211 includes a radio reception unit 211a, a demultiplexing unit 211b, a demodulation unit 211c, and a decoding unit 211d.

[0093] The radio receiving unit 211a performs down-conversion, removal of unnecessary frequency components, control of amplification level, orthogonal demodulation, conversion to digital signals, removal of guard intervals, extraction of frequency domain signals by fast Fourier transform, etc. on the uplink signal. The demultiplexing unit 211b demultiplexes uplink channels, such as physical uplink shared channels (PUSCH) or physical uplink control channels (PUCCH), and uplink reference signals from the signals output from the radio receiving unit 211a. The demodulation unit 211c demodulates the received signal using a modulation scheme such as binary phase shift keying (BPSK) or quadrature phase shift keying (QPSK) with respect to the modulation symbols of the uplink channel. The modulation scheme used by the demodulation unit 211c can be 16 quadrature amplitude modulation (QAM), 64QAM, 256QAM, etc. The decoding unit 211d performs decoding processing on the demodulated coded bits of the uplink channel. The decoded uplink data and uplink control information are output to the control unit 23.

[0094] The transmission processing unit 212 performs a process of transmitting downlink control information and downlink data. The transmission processing unit 212 includes a coding unit 212a, a modulation unit 212b, a multiplexing unit 212c, and a radio transmission unit 212d.

[0095] The coding unit 212a encodes the downlink control information and downlink data input from the control unit 23 using a coding method such as block coding, convolution coding, turbo coding, etc. The modulation unit 212b modulates the coded bits output from the coding unit 212a by a predetermined modulation scheme such as BPSK, QPSK, 16QAM, 64QAM or 256QAM. The multiplexing unit 212c multiplexes the modulation symbols and downlink reference signals of each channel and arranges the multiplexing results in a predetermined resource unit. The radio transmission unit 212d performs various types of signal processing on the signal from the multiplexing unit 212c. For example, the radio transmission unit 212d performs processing such as conversion to the time domain by fast Fourier transform, adding a guard interval, generating a baseband digital signal, converting to an analog signal, orthogonal coding, up-conversion, removing additional frequency components, and power amplification. The signal generated by the transmission processing unit 212 is transmitted from the antenna 213.

[0096] The storage unit 22 is a storage device capable of reading and writing data, such as DRAM, SRAM, flash memory or hard disk. The storage unit 22 acts as a storage device of the base station 20. The storage unit 22 stores switching information. The switching information is information used by the terminal device 50 to switch the base station. The switching information includes, for example, information such as resource information, trigger information, timing advance information, etc.

[0097] Resource information is information related to radio resources used by the terminal device 50 in implementing radio communications with a base station configured as a mobile switching destination candidate. Trigger information is information used by the terminal device 50 to decide whether to switch the connection destination base station. Timing advance information is information related to the timing advance that enables the terminal device 50 to connect to the base station as a switching destination candidate. Resource information, trigger information, and timing advance information will be described in detail later.

[0098] The control unit 23 is a controller that controls each unit of the base station 20. The control unit 23 is implemented by a processor such as a central processing unit (CPU) or a microprocessing unit (MPU), for example. For example, the control unit 23 is implemented by the processor executing various programs stored in a storage device inside the base station 20 using a random access memory (RAM) or the like as a work area. The control unit 23 can be implemented by an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). Any of the CPU, MPU, ASIC, and FPGA can be regarded as a controller.

[0099] <2-5. Configuration of terminal equipment>

[0100] Next, the configuration of the terminal device 50 will be described. Figure 7 1 is a diagram showing one configuration example of a terminal device 50 according to one embodiment of the present disclosure. The terminal device 50 includes a radio communication unit 51 , a storage unit 52 , a network communication unit 53 , an input-output unit 54 , and a control unit 55 . Figure 7 The configuration shown in FIG. 5 is a functional configuration, and the hardware configuration may be different from the functional configuration. The functions of the terminal device 50 may be implemented in a plurality of physically separated configurations in a distributed manner. Figure 7 The configuration shown in is an example, and the radio communication unit 51, the storage unit 52, the network communication unit 53, the input-output unit 54, and the control unit 55 are not all essential components. For example, from the perspective of the embodiments of the present disclosure, at least the network communication unit 53 and the input-output unit 54 may not be essential components.

[0101] The radio communication unit 51 is a radio communication interface for implementing radio communication with other radio communication devices (e.g., base stations 20, 30, 40). The radio communication unit 51 supports one or more radio access methods. For example, the radio communication unit 51 supports both NR and LTE. In addition to NR or LTE, the radio communication unit 51 can support W-CDMA or cdma 2000. The radio communication unit 51 includes a receiving processing unit 511, a sending processing unit 512, and an antenna 513. The radio communication unit 51 may include a plurality of receiving processing units 511, a plurality of sending processing units 512, and a plurality of antennas 513. When the radio communication unit 51 supports a plurality of radio access methods, each unit of the radio communication unit 51 may be configured separately for each radio access method. For example, the receiving processing unit 511 and the sending processing unit 512 may be configured separately by LTE and NR.

[0102] The reception processing unit 511 processes a downlink signal received through the antenna 513. The reception processing unit 511 includes a radio reception unit 511a, a demultiplexing unit 511b, a demodulation unit 511c, and a decoding unit 511d.

[0103] The radio receiving unit 511a performs down-conversion, removes unnecessary frequency components, controls the amplification level, orthogonal demodulation, converts to digital signals, removes guard intervals, extracts frequency domain signals by fast Fourier transform, etc. on the downlink signal. The demultiplexing unit 511b demultiplexes the downlink channel, the downlink synchronization signal and the downlink reference signal from the signal output from the radio receiving unit 511a. The downlink channel is, for example, a channel such as a physical broadcast channel (PBCH), a physical downlink shared channel (PDSCH) or a physical downlink control channel (PDCCH). The demodulation unit 211c demodulates the received signal using a modulation scheme such as BPSK, QPSK, 16QAM, 64QAM or 256QAM for the modulation symbol of the downlink channel. The decoding unit 511d performs decoding processing on the demodulated coded bits of the downlink channel. The decoded downlink data and downlink control information are output to the control unit 23.

[0104] The transmission processing unit 512 performs a process of transmitting uplink control information and uplink data. The transmission processing unit 512 includes a coding unit 512a, a modulation unit 512b, a multiplexing unit 512c, and a radio transmission unit 512d.

[0105] The coding unit 512a encodes the uplink control information and uplink data input from the control unit 55 using a coding method such as block coding, convolution coding, turbo coding, etc. The modulation unit 512b modulates the coded bits output from the coding unit 512a by a predetermined modulation scheme such as BPSK, QPSK, 16QAM, 64QAM or 256QAM. The multiplexing unit 512c multiplexes the modulation symbols and downlink reference signals of each channel and arranges the multiplexing results in a predetermined resource unit. The radio transmission unit 512d performs various types of signal processing on the signal from the multiplexing unit 512c. For example, the radio transmission unit 512d performs processing such as conversion to the time domain by inverse fast Fourier transform, adding a guard interval, generating a baseband digital signal, converting to an analog signal, orthogonal coding, up-conversion, removing additional frequency components, and power amplification. The signal generated by the transmission processing unit 512 is transmitted from the antenna 513.

[0106] The storage unit 52 is a storage device capable of reading and writing data, such as a DRAM, SRAM, flash memory, or hard disk. The storage unit 52 acts as a storage device of the terminal device 50. The storage unit 52 stores switching information. The switching information is information obtained from the base station 20, 30, or 40, and is used by the terminal device 50 to switch the base station. The switching information includes, for example, information such as resource information, trigger information, and timing advance information. The resource information, trigger information, and timing advance information will be described in detail later.

[0107] The network communication unit 53 is a communication interface for communicating with other devices. For example, the network communication unit 53 is a LAN interface such as a NIC. The network communication unit 53 can be a wired interface or a wireless interface. The network communication unit 53 acts as a network communication device of the terminal device 50. The network communication unit 53 communicates with other devices under the control of the control unit 55.

[0108] The input-output unit 54 is a user interface for exchanging information with a user. For example, the input-output unit 54 is a device for implementing various operations by the user, such as a keyboard, a mouse, an operation key, and a touch pad. Alternatively, the input-output unit 54 is a display device such as a liquid crystal display or an organic electroluminescent display. The input-output unit 54 can be an acoustic device such as a speaker or a buzzer. The input-output unit 54 can be a lighting device such as a light-emitting diode (LED) lamp. The input-output unit 54 serves as an input and output device (input device, output device, operation device, or notification device) of the terminal device 50.

[0109] The control unit 55 is a controller that controls each unit of the terminal device 50. The control unit 55 is implemented by a processor such as a CPU or an MPU, for example. For example, the control unit 55 is implemented by the processor using a RAM or the like as a work area to execute various programs stored in a storage device inside the terminal device 50. The control unit 55 can be implemented by an integrated circuit such as an ASIC or an FPGA. Any of the CPU, MPU, ASIC, and FPGA can be regarded as a controller.

[0110] <2-6. Initial Access Processing>

[0111] Next, the operation of the communication system 1 will be described. First, the initial access process will be described. The initial access is a process for transitioning from an idle state (RRC_IDLE) in which the UE (terminal device 50) has not established a connection with any of the RAN (base station), the base station 20, and the base station 30 to a connected state (RRC_CONNECTED) in which a connection has been established with any of the RANs.

[0112] Figure 8is a flowchart showing an example of initial access processing. Figure 8 The initial access process described below is performed, for example, when power is applied to the UE (terminal device 50).

[0113] First, the terminal device 50 in the idle state implements a cellular search. Cellular search is a procedure in which the UE detects the physical cell ID (PCI) of the cell and obtains time and frequency synchronization. The cellular search of this embodiment includes the process of detecting synchronization signals and decoding PBCH. The synchronization signal (SS) in NR includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). In NR, PSS, SSS and PBCH are sent as a set. The set is called an SS / PBCH block (SSB). Multiple SSBs are sent per unit time (e.g., half a frame (5ms)). Multiple SSBs sent per half frame are called SSB bursts, SS bursts, SSB burst sets or SS burst sets. SSB bursts are periodically repeated according to the period of the SSB burst. An index (SSB index) is assigned to each of the multiple SSBs in an SSB burst. An SSB index is associated with a beam, for example. The number of multiple SSBs in an SSB burst depends on the subcarrier spacing associated with the frequency band. The control unit 55 of the UE (terminal device 50) detects the SSB of the cell (step S101). More specifically, the UE detects the SSB corresponding to the best quality beam in the SSB burst. The control unit 55 implements synchronization in the downlink with the cell based on the detected synchronization signal. After establishing downlink synchronization u, the control unit 55 attempts to decode the PBCH and obtain the dominant information block (MIB) as part of the system information (step S102).

[0114] System information is information used to report the configuration in the cell to which the system information is sent. System information includes, for example, information about cell access (such as random access) (such as RACH-Config), information about cell selection, information about other RATs and other systems, and the like. System information includes MIB and system information block (SIB). MIB is physical layer information necessary for receiving SIB, etc., and is fixed payload size information notified through PBCH. MIB includes downlink system bandwidth, part of the system frame number, SIB scheduling information, and the like. SIB is other system information outside MIB and is notified through PDSCH.

[0115] System information can be classified into first system information, second system information and third system information. The first system information and the second system information include information about cellular access, information about acquisition of other system information and information about cellular selection. In LTE, the information included in the MIB is the first system information. The information included in SIB 1 and SIB2 in the SIB is the second system information. The remaining system information is the third system information.

[0116] In addition, in NR, system information is notified from the NR cell. A physical channel carrying system information may be transmitted in a slot or a mini slot. A mini slot is defined by a smaller number of symbols than the number of symbols of a slot. Since a physical channel carrying system information is transmitted in a mini slot, the time required for beam scanning is shortened and overhead can be reduced. For NR, first system information is transmitted on the NR-PBCH, and second system information is transmitted on a physical channel different from the NR-PBCH.

[0117] The control unit 55 of the terminal device 50 acquires the second system information based on the MIB (i.e., the first system information) (step S103). As described above, the second system information includes SIB 1 and SIB 2. SIB 1 is the access control information of the cell and the scheduling information of other system information outside SIB 1. In the case of NR, SIB 1 includes information related to cell selection (e.g., cellSelectionInfo), information related to cell access (e.g., cellAccessRelatedInfo), information related to connection establishment failure control (e.g., connEstFailureControl), scheduling information of other system information outside SIB1 (e.g., si-SchedulingInfo), configuration of the serving cell, and the like. The configuration of the serving cell includes cell-specific parameters and includes downlink configuration, uplink configuration, TDD configuration information, and the like. The uplink configuration includes RACH configuration, and the like. In the case of LTE, SIB 1 includes access information of the cell, cell selection information, maximum uplink transmission power information, TDD configuration information, periodicity of system information, mapping information of system information, length of system information (SI) window, and the like. In the case of NR, SIB 2 includes cell reselection information (e.g., cellReselectionInfoCommon) and cell reselection serving frequency information (e.g., crelReselectionServingFreqInfo). In the case of LTE, SIB2 includes connection prohibition information, radio resource configuration information common to each cell (radioResourceConfigCommon), uplink carrier information, etc. The radio resource configuration information common to each cell includes configuration information of the physical random access channel (PRACH) and random access channel (RACH) common to each cell.

[0118] In the case where the control unit 55 fails to acquire the system information necessary for establishing a link, the control unit 55 of the terminal device 50 determines that access to the cell is prohibited. For example, in the case where all the first system information and the second system information cannot be acquired, the control unit 55 determines that access to the cell is prohibited. In this case, the control unit 55 ends the initial access process.

[0119] In the case where the system information can be acquired, the control unit 55 performs a random access procedure based on the first system information and / or the second system information (step S104). The random access procedure may be referred to as a random access channel procedure (RACH procedure) or a RA procedure. In the RACH procedure, the UE first sends a random access preamble, and then monitors a random access response identified by the RA-RNTI on the PDCCH of the cell for a period of time indicated by the configured IE ra-ResponseWindow. On the other hand, when the sent preamble arrives at the RAN without a conflict, a random access response including a preamble identifier is sent from the RAN to the UE, and the preamble identifier corresponds to PREAMBLE_INDEX which is an index of the sent preamble. When the UE receives a random access response including a preamble identifier corresponding to the sent PREAMBLE_INDEX while the ra-ResponseWindow is running, the UE recognizes that the random access procedure is successfully completed. Subsequently, when the UE sends an RRCSetupRequest message through Msg3 and receives an RRCSetup message from the RAN in response to the RRCSetupRequest message, the UE (terminal device 50) transitions from the idle state (RRC_IDLE) to the connected state (RRC_CONNECTED) (enters RRC connected) and identifies the current cell (the cell on which the RACH procedure is implemented and the RRC setup procedure is implemented) as the primary cell.

[0120] <2-7. Example of HARQ Procedure>

[0121] Here, in the communication process (e.g., the initial access process described above) performed by the control unit 55 of the terminal device 50 and the control unit (e.g., the control unit 23) of the base station device (e.g., the base station 20, the base station 30), hybrid ARQ (HARQ) is used for data error correction. For example, HARQ is used for PDSCH data transmission, PUSCH data transmission, and PSSCH data transmission.

[0122] HARQ is a means for implementing error correction by soft combining the first transmitted data and the retransmitted data to obtain coding gain. In order to implement HARQ, the base station device or the terminal device 50 keeps the data that failed to be decoded in the HARQ buffer, combines the retransmitted data and the retained data, and implements error correction. More specifically, a HARQ process may include the following operations. The MAC entity in the UE (terminal device 50) determines whether the received data is a new transmission or a retransmission from the new data indicator (NDI) in the DCI in which the transmission resources of the data are scheduled. In the case where the received data is a new transmission, the MAC entity attempts to decode the received data. If the received data is a retransmission and the data of the transport block is not successfully decoded, the MAC entity instructs the physical layer to combine the data currently in the soft buffer for the transport block with the received data, and attempts to decode the combined data. If the data attempted to be decoded by the MAC entity has been successfully decoded, or if the data has been successfully decoded previously, the decoded MAC PDU is carried to a higher layer or a disassembly and demultiplexing entity. If the data attempted to be decoded by the MAC entity is not successfully decoded, and if the data was not successfully decoded before, the physical layer is instructed to replace the data in the soft buffer for the transport block with the data attempted to be decoded. Subsequently, the MAC entity instructs the physical layer to generate (multiple) acknowledgments, that is, HARQ feedback (ACK / NACK) for the data in the transport block.

[0123] A HARQ process is implemented for each HARQ process to which identification information (e.g., a HARQ process identifier) ​​is assigned. That is, in the case of multiple HARQ processes, it is possible to implement the HARQ processes in parallel. The base station device or the terminal device 50 may maintain one or more HARQ processes. More specifically, the MAC entity includes a HARQ entity for each service cell. The HARQ entity maintains a large number of parallel HARQ processes. The HARQ process can be applied not only to the downlink, but also to the uplink. In this case, the MAC entity includes a HARQ entity for each service cell for which the uplink is configured. As described above, each HARQ process is associated with a HARQ process identifier. The number of HARQ processes for the downlink and the number of HARQ processes for the uplink may be different or the same. The HARQ entity, for example, forwards the HARQ information and the associated TB to the corresponding HARQ process.

[0124] The base station device in the following description can be implemented regardless of whether it is the base station 20 or the base station 30 as a communication device, such as a satellite station, a drone, a balloon, or an airplane. In the following description, when a specific example is shown, a part of the base station 30 and the terminal device shows and describes specific values, but the values ​​are not dependent on the example, and other values ​​may be used.

[0125] In the following description, resource means frequency, time, resource unit (including REG, CCE, CORESET), resource block, bandwidth part, component carrier, symbol, subsymbol, time slot, mini time slot, sub time slot, sub frame, frame, PRACH opportunity, opportunity, code, multiple access physical resource, multiple access signature, subcarrier spacing (parameter set), etc. The HARQ process identifier in the following description may be replaced with the HARQ process number.

[0126] The HARQ procedure will be described here by exemplifying PDSCH data transmission from a base station device (eg, base stations 20 , 30 ) to a terminal device 50 . Fig. 9 is a sequence diagram showing an example of the HARQ procedure.

[0127] like Fig. 9 As shown in , a control unit (e.g., control unit 23) of a base station device (e.g., base station 20, base station 30) uses HARQ to send PDSCH data to a terminal device 50 via radio communication (e.g., radio communication unit 21) (step S201). That is, the UE (terminal device 50) receives PDSCH data. More specifically, the UE monitors the PDCCH in a time period determined based on a configuration related to PDCCH monitoring, such as discontinuous reception (DRX), BWP, or SCell configuration. Here, when there is data addressed to the UE (that is, when the PDCCH indicates the allocation of data (PDSCH) addressed to the UE), the UE receives data on the corresponding PDSCH. Subsequently, with the PDCCH indicating the PDSCH data (DL transmission) as a trigger, the UE starts drx-HARQ-RTT-TimerDL for the HARQ processing associated with the data (transmission block carried on the PDSCH). The timing of starting drx-HARQ-RTT-TimerDL is the first OFDM symbol after the last OFDM symbol of the corresponding transmission carrying DL HARQ feedback.Assume that HARQ process #1 is assigned as the HARQ process identifier to the HARQ process for PDSCH data transmission.

[0128] The control unit 55 (e.g., MAC entity) of the terminal device 50 that receives the PDSCH data from the base station device attempts to decode the PDSCH data (i.e., the data in the transport block carried by the PDSCH). As described above, when the received data is newly transmitted data, decoding is newly attempted, and when the received data is retransmitted data, decoding is attempted after combining the data already stored in the soft buffer with the received data. Here, it is assumed that the PDSCH data is not successfully decoded (step S202).

[0129] Due to the decoding failure of the PDSCH data, the control unit 55 (e.g., MAC entity) of the terminal device 50 stores the PDSCH data that failed to be decoded in the HARQ buffer of HARQ processing #1 in the storage segment ensured in the storage unit 52 (step S204). In the case where there is already data stored in the HARQ buffer, the data is replaced. Next, a NACK is sent to the base station device through the radio communication unit 51 (step S203). If the operated drx-HARQ-RTT-TimerDL expires, when the HARQ processed data is not successfully decoded, the terminal device causes the UE to start drx-RetransmissionTimerDL. The timing for starting drx-RetransmissionTimerDL is the first OFDM symbol after the expiration of drx-HARQ-RTT-TimerDL. Fig. 9 In the case of , since decoding of data corresponding to HARQ process #1 fails in step S202, drx-RetransmissionTimerDL starts.

[0130] Fig.10 : is an explanatory diagram showing an overview of the HARQ buffer. Fig.10 As shown in , a storage section 521 for each HARQ process is assigned to the storage unit 52. As a result, the terminal device 50 can maintain one or more HARQ processes. Similar to the terminal device 50, the base station device (e.g., base station 20, base station 30) can also maintain one or more HARQ processes in a storage unit (e.g., storage unit 22).

[0131] In the example shown, the control unit 55 stores the PDSCH data in the HARQ buffer 522a in the storage section 522 of the HARQ process #1 associated with the unsuccessfully decoded PDSCH data. In the event that existing data is stored in the HARQ buffer, the data is replaced.

[0132] Back to Fig. 9, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) that receives the NACK retransmits the PDSCH data to the terminal device 50 through radio communication (e.g., radio communication unit 21) (step S205). In other words, the UE (terminal device 50) receives the retransmission of the PDSCH data. More specifically, the UE monitors the PDCCH while drx-RetransmissionTimerDL is running. drx-RetransmissionTimerDL indicates the time when the UE expects DL retransmission from the RAN. Therefore, DL retransmission is implemented to the UE while drx-RetransmissionTimerDL is running.

[0133] The control unit 55 of the terminal device 50 receiving the retransmission of the PDSCH data implements soft combination of the data stored in the HARQ buffer 522a of the HARQ process #1 and the retransmission data to decode the PDSCH data (step S206). Here, it is assumed that the PDSCH data is successfully decoded (step S207).

[0134] Due to successful decoding of the PDSCH data, the control unit 55 of the terminal device 50 sends ACK to the base station device through the radio communication unit 51 (step S208). Next, the control unit 55 of the terminal device 50 clears the data in the HARQ buffer 522a of the HARQ process #1 (step S209).

[0135] <2-8, Sending delay issue>

[0136] For example, in the case of NTN communication, since the propagation distance between the terminal device 50 and the base station device (eg, base station 20, base station 30) including an airplane, a drone, etc. is long, the propagation delay increases.

[0137] When the propagation delay is large, there is no free HARQ buffer in the base station device or the terminal device 50, and the number of HARQ processes may be insufficient. For example, when the base station device sends data and the terminal device 50 receives data, if the decoding is successful, the terminal device 50 feeds back ACK to the base station device and flushes (clears) the data in the HARQ buffer, and the process ends. On the other hand, when the decoding fails, the terminal device 50 feeds back NACK to the base station device, and it is necessary to keep the received data in the HARQ buffer in order to implement soft combination with the data retransmitted after the NACK is returned.

[0138] The base station device and the terminal device 50 can use one or more HARQ processes in parallel, and when the propagation delay is small, the time from returning NACK to sending retransmission data is short, and there is no problem of insufficient HARQ processing. However, when the propagation delay is large, the time until NACK is returned and retransmission is implemented becomes longer, so there is a possibility that the HARQ processing becomes insufficient (or it takes time to resolve the insufficient state).

[0139] <2-9. Overview of Examples>

[0140] In view of the above transmission delay problem, in the base station device and the terminal device 50 according to the present embodiment, under the control of the control unit (e.g., the control unit 23, 55), the disabling information (HARQ feedback disabling) for disabling feedback for retransmission in HARQ is notified through the radio communication unit (e.g., the radio communication unit 21, 51). As described above, by disabling feedback for retransmission (HARQ feedback disabling), the data in the buffer is immediately flushed (emptied) without storing the received data in the HARQ buffer, and the HARQ process is prevented from becoming insufficient.

[0141] That is, HARQ feedback disabling is to complete data transmission by only first transmission or by repeatedly transmitting single or multiple spatially multiplexed transport blocks without ACK / NACK notification from the terminal device 50. At this time, ACK / NACK return of the terminal device 50 cannot be implemented.

[0142] For example, in the case of considering the downlink, the HARQ feedback sent for the PDSCH corresponds to the uplink control information (UCI) sent from the terminal device 50. As an example, when the decoding of the PDSCH sent from the base station device (e.g., base station 20, base station 30) fails, the control unit 55 of the terminal device 50 sends UCI (NACK) to the base station device through the radio communication unit 51. As a result, the control unit of the base station device (e.g., control unit 23) retransmits the data through the radio communication unit (e.g., radio communication unit 21). On the other hand, when the PDSCH sent from the base station device is successfully decoded, the control unit 55 of the terminal device 50 sends UCI (ACK) to the base station device through the radio communication unit 51, and the base station device sends the next new data.

[0143] In the case of considering the uplink, the HARQ feedback sent for the PUSCH corresponds to, for example, downlink control information (DCI) sent from the base station device, or corresponds to explicit ACK / NACK information. For example, when the PUSCH sent from the terminal device 50 is not successfully decoded, the control unit (e.g., control unit 23) of the base station device sends a DCI including information indicating retransmission to the terminal device 50 through a radio communication unit (e.g., radio communication unit 21). As a result, the control unit 55 of the terminal device 50 retransmits the data. On the other hand, when the PUSCH sent from the terminal device 50 is successfully decoded, the control unit (e.g., control unit 23) of the base station device sends a DCI including information indicating the first transmission to the terminal device 50 through a radio communication unit (e.g., radio communication unit 21). As a result, the control unit 55 of the terminal device 50 sends the next new data.

[0144] In the case of considering the side link, the HARQ feedback sent for the PSSCH corresponds to the side link control information (SCI) or ACK / NACK information sent from the terminal device 50. For example, when the decoding of the PSSCH sent from the terminal device 501 fails, the control unit 55 of the terminal device 502 sends the SCI including information indicating the retransmission to the terminal device 501 through the radio communication unit 51. As a result, the control unit 55 of the terminal device 501 retransmits the data through the radio communication unit 51. On the other hand, when the PSSCH sent from the terminal device 501 is successfully decoded, the control unit 55 of the terminal device 502 sends the SCI including information indicating the first transmission to the terminal device 501 through the radio communication unit 51. As a result, the control unit 55 of the terminal device 501 sends the next new data through the radio communication unit 51.

[0145] For example, when the PSSCH transmitted from the terminal device 501 is not successfully decoded, the control unit 55 of the terminal device 502 transmits NACK to the terminal device 501 through the radio communication unit 51. As a result, the control unit 55 of the terminal device 501 retransmits the data through the radio communication unit 51. On the other hand, when the PSSCH transmitted from the terminal device 501 is successfully decoded, the control unit 55 of the terminal device 502 transmits ACK to the terminal device 501 through the radio communication unit 51. As a result, the control unit 55 of the terminal device 501 transmits the next new data through the radio communication unit 51.

[0146] As described above, HARQ feedback corresponds to information such as UCI, DCI, SCI, and ACK / NACK information. In the case of implementing HARQ feedback disabling, the base station device (e.g., base station 20, base station 30) and the terminal device 50 can send and receive the next new data without waiting for the transmission and reception of UCI, DCI, SCI, ACK / NACK information, etc. At this time, the HARQ buffer of the base station device (e.g., base station 20, base station 30) and the terminal device 50 does not need to keep sending and receiving data. HARQ feedback disabling / enabling can be applied to any one of the downlink, uplink, and sidelink, and is not limited to any one of them.

[0147] In this embodiment, a configuration in which HARQ feedback disabling is implemented for each HARQ process is illustrated, but the unit for implementing HARQ feedback disabling can be appropriately set. For example, in addition to each HARQ process, HARQ feedback disabling can be implemented for each cell, each beam, each component carrier, each bandwidth part (BWP), or each user equipment (UE). Specifically, by replacing the HARQ process illustrated in this embodiment with a cell, a sector, a beam, a component carrier, a BWP, or a UE, the unit for implementing HARQ feedback disabling can be appropriately changed.

[0148] For example, in the unit of a cell or sector, the enabling and disabling of HARQ feedback may be switched for each serving cell (that is, for each HARQ entity). In other words, the enabling and disabling of HARQ feedback may be switched in a common configuration or timing for multiple terminals in a cell. In the unit of a beam (that is, an SSB or a CSI-RS), the enabling and disabling of HARQ feedback may be switched for each transmit beam or each receive beam. In the unit of a component carrier, the enabling and disabling of HARQ feedback may be switched for each component carrier. In the unit of a bandwidth part (BWP), the enabling / disabling of HARQ feedback may be switched for each BWP. In the unit of a UE, the enabling and disabling of HARQ feedback may be switched for each terminal. In the unit of a HARQ process, the enabling and disabling of HARQ feedback may be switched for each HARQ process (that is, for each TB). In the unit of a packet, the enabling and disabling of HARQ feedback may be switched for each transmit packet. The switching of the preceding units may be combined.

[0149] A specific example of HARQ feedback disabling processing in units of HARQ processes will be described here for each of downlink and uplink.

[0150] <2-10. Example of HARQ disabling processing (downlink)>

[0151] Fig.11 is a sequence diagram showing an example of HARQ disabling processing according to an embodiment of the present disclosure. Specifically, as an example, Fig.11 FIG. 4 shows the disabling of HARQ feedback in units of HARQ processes in the downlink. Fig.11 In the case of, HARQ process #1 is set to HARQ feedback enabled, and HARQ process #2 is set to HARQ feedback disabled.

[0152] like Fig.11 As shown in, first, as a trigger for implementing HARQ feedback disabling, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) notifies the UE (terminal device 50) to disable the predetermined HARQ processing through radio communication (e.g., radio communication unit 21) (step S301).

[0153] Specifically, in step S301, the base station device implements a notification to disable HARQ feedback of HARQ process #2. The notification includes, for example, semi-static notification (e.g., radio resource control (e.g., RRC reconfiguration message, RRC setup message, RRC recovery message) signaling, etc.) and dynamic notification (e.g., DCI). The control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) can implement any of the above notification methods. In the case where the UE (terminal device 50) implements dual connections with multiple base stations, a semi-static notification can be received from the MN through SRB 0, 1, 2 or directly from the SN through SRB 3. A dynamic notification can be received directly from each of the MN and the SN. For example, in the case of ENDC, a semi-static notification generated by the SN can be sent to the MN through the X2 interface, and provided to the UE by the MN in the RRC signaling. In the case of ENDC, a dynamic notification can be provided to the UE independently of each of the PHY layers hosted by the MN and the PHY layers hosted by the SN. Semi-static notification or dynamic notification can be implemented, or a combination of implementations can be implemented. A semi-static notification may be sent to the UE in notification information (eg, MIB, SIB).

[0154] Semi-static notification includes a method of explicitly notifying HARQ disabling and a method of implicitly notifying HARQ disabling. In explicit notification, HARQ disabling is notified, for example, through system information / RRC signaling.

[0155] In implicit notification, the terminal device 50 issues a notification to decide whether to disable HARQ feedback based on system information or other information notified through RRC signaling. For example, in implicit notification, the terminal device 50 can use the following information in system information, etc. to decide (consider) disabling.

[0156] - Location information of base station equipment and terminal equipment 50

[0157] - Propagation distance and propagation delay information between the base station device and the terminal device 50

[0158] - Altitude of base station equipment and terminal equipment 50

[0159] - The moving speed of the base station device and the terminal device 50

[0160] -Timing advance information

[0161] -Power control information

[0162] For example, when the timing advance is greater than a predetermined value, the control unit 55 of the terminal device 50 disables HARQ feedback. When the timing advance is less than a predetermined value, the control unit 55 of the terminal device 50 enables HARQ feedback.

[0163] The control unit 55 of the terminal device 50 may decide whether to disable HARQ feedback based on the information about power control. For example, when the power control is greater than a predetermined value, the control unit 55 of the terminal device 50 disables HARQ feedback. When the power control is less than a predetermined value, the control unit 55 of the terminal device 50 enables HARQ feedback.

[0164] In dynamic notification, for example, when it is determined that a HARQ process is exhausted or may be exhausted, HARQ feedback for all or some HARQ processes is disabled (dynamic HARQ disabling is introduced).

[0165] The dynamic notification includes a method of explicitly notifying HARQ disabling and a method of implicitly notifying HARQ disabling.

[0166] Examples of explicit methods include the following.

[0167] - Notification by adding HARQ disable field to DCI

[0168] - Notify HARQ disable request via UCI

[0169] Here, the HARQ disabling request is a HARQ disabling request for the terminal device 50 to request the base station device to perform HARQ disabling. The base station device that has received the HARQ disabling request can implement HARQ disabling based on the notified information.

[0170] - Notification of where HARQ feedback should not be stopped and where HARQ feedback may be stopped.

[0171] Examples of implicit methods include the following methods.

[0172] - Notification of other physical information (CORESET, search space, scrambling (DMRS, RNTI)) using PDCCH

[0173] - Notification via reference signal sequence / port

[0174] -Handover initiated by DMRS sequence

[0175] -Switching of antenna ports

[0176] In the case of dynamically implementing HARQ disabling, the control unit of the base station device (such as the control unit 23) or the control unit 55 of the terminal device 50 can implement the operation of dynamically enabling the disabled HARQ feedback. The timing of UE disabling / enabling can be specified in the standard, or can be notified to the UE from the RAN.

[0177] For example, the operation of dynamically disabling / enabling HARQ feedback may be applied under the following conditions (a-1, a-2, b-1, b-2).

[0178] (a-1) The operation is applied from the subframe n (or time slot n) in which the DCI including the indication of disabling / enabling is received.

[0179] (a-2) Applying operation to n+k subframes (for example, k=4) starting from subframe n in which DCI including an indication of disabling / enabling is received (or starting from slot n)

[0180] (b-1) Applying operation from the process indicated by the HARQ process number indicated by the DCI including the indication of disable / enable

[0181] (b-2) Applying operation to the process next to the process indicated by the HARQ process number indicated by the DCI including the indication of disable / enable

[0182] At least one of (a-1) to (b-2) described above can be notified from the base station to the UE through semi-static notification or dynamic notification. The value of k in (a-2) described above can also be notified from the base station to the UE through semi-static notification or dynamic notification.

[0183] The control unit (eg, control unit 23) of the base station device (eg, base station 20, base station 30) may select a target for implementing HARQ feedback disabling.

[0184] For example, in the case where HARQ feedback is disabled in units of cells, sectors, and beams, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) sets the terminal device 50 belonging to the cell, sector, and beam for which HARQ feedback disabling is implemented as the target of HARQ feedback disabling. Subsequently, the control unit (e.g., control unit 23) notifies the target terminal device 50 of the disabling of HARQ feedback. If the target of HARQ feedback disabling is all terminal devices in the cell (that is, if HARQ feedback disabling is set to be specific to the cell), the notification can be implemented by using system information. In the case where the target of HARQ feedback disabling is for a specific terminal device (that is, if HARQ feedback disabling is configured to be specific to UE), dedicated RRC signaling (e.g., RRCReconfiguration message, RRCSetup message, RRCResume message) can be used to implement the notification. In the dedicated RRC signaling, HARQ feedback disabling can include one or more configurations in units of serving cells and in units of beams (e.g., SSB, CSI-RS).

[0185] In the case of disabling HARQ feedback in units of component carriers and BWPs, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) sets the component carrier for implementing HARQ feedback disabling and the terminal device 50 implementing communication in the BWP as the target of HARQ feedback disabling. Subsequently, the control unit (e.g., control unit 23) notifies the target terminal device 50 of the disabling of HARQ feedback through RRC signaling or DCI.

[0186] In the case of disabling HARQ feedback in units of UEs, a control unit (e.g., control unit 23) of a base station device (e.g., base station 20, base station 30) sets the UE implementing HARQ feedback disabling as a target for HARQ feedback disabling. Subsequently, the control unit (e.g., control unit 23) notifies the target terminal device 50 of the UE of the disabling of HARQ feedback through RRC signaling or DCI.

[0187] When HARQ feedback is disabled in units of HARQ processes, a control unit (eg, control unit 23) of a base station device (eg, base station 20, base station 30) disables HARQ feedback in the HARQ process in which HARQ feedback disabling is implemented.

[0188] For example, assume that the total number of HARQ processes is X (the HARQ process is described here as an example, but the HARQ process may be replaced with a cell, a sector, a beam, a component carrier, a BWP, or a UE).

[0189] First, HARQ feedback in (XA) HARQ processes is still enabled, and HARQ feedback in A HARQ processes is disabled. Here, the value of A is explicitly or implicitly notified.

[0190] For example, explicit notification of the value of A may be any of the following.

[0191] - Notification via System Information Block (SIB)

[0192] -Notification via RRC signaling

[0193] - Notification via DCI

[0194] Furthermore, implicit notification of the value of A may be any of the following.

[0195] - Notification of other physical information (CORESET, search space, scrambling (DMRS, RNTI)) using PDCCH

[0196] - Notification via reference signal sequence / port

[0197] - Notification by base station type

[0198] It should be noted that, in the case of notification by base station type, for example, A=X when the base station is GEO, A=Y (Y<=X) when the base station is MEO, and A=Z (Z<=Y) when the base station is LEO.

[0199] Instead of the number, the HARQ process number to be disabled may be explicitly notified. For example, in the notification of the HARQ process number to be disabled, HARQ process ID=14, 15 may be disabled.

[0200] In addition to the X HARQ processes, B HARQ processes for disabling may be added. Considering that it is not necessary to keep data in the HARQ buffer in the disabled HARQ process, it is possible to add the HARQ process for disabling in addition to the existing HARQ processes. The number B to be added may be one or more.

[0201] In the foregoing description, the HARQ process for disabling is described. However, since the retransmission process is not implemented, the process may not be included in one of the HARQ processes. That is, the process may be treated as a process for disabling and as a process different from the HARQ process.

[0202] In the case where HARQ feedback is set to be disabled, as an exception, HARQ feedback may not be disabled in the following cases.

[0203] - UL transmission transmitted under the UL grant of the random access response uses the HARQ process identifier 0, and in this transmission, even if the HARQ feedback is included in the deactivation condition, the HARQ feedback is not disabled.

[0204] - When the new data indicator in the DCI carried on the PDCCH corresponding to the HARQ process does not indicate new data (in the case of new data indicator bit = 0), an implementation may be implemented such that HARQ feedback is not disabled.

[0205] In the DCI notification in the case where HARQ feedback has been disabled, there is a 4-bit notification segment (HARQ process number) for notifying the HARQ process identifier and a 1-bit notification segment (new data indicator (NDI)) for notifying the first transmission or retransmission. In the case where HARQ feedback is disabled in all HARQ processes (disabling in units of cells and component carriers, etc.), the notification segment is an unnecessary segment. Such an unnecessary notification segment has uses in applications such as zero filling and other applications. For example, such an unnecessary notification segment can be used as a notification segment for information about the error rate characteristic compensation means described later.

[0206] Next, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) sends DCI and PDSCH data (hereinafter referred to as PDSCH data) to the terminal device 50 using HARQ through radio communication (e.g., radio communication unit 21) (step S302). It is assumed that HARQ process #1 is assigned to the HARQ process for data transmission as the HARQ process identifier. The control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) keeps the transmitted PDSCH data in the HARQ buffer of HARQ process #1 in the storage unit (e.g., storage unit 22) (step S303).

[0207] The control unit 55 of the terminal device 50 that receives the PDSCH data of HARQ process #1 from the base station device decodes the PDSCH data. In response to receiving the PDSCH data (that is, the fact that the PDCCH scheduling the PDSCH indicates DL transmission), the UE (terminal device 50) starts drx-HARQ-RTT-TimerDL. Here, it is assumed that the PDSCH data of HARQ process #1 is not successfully decoded (step S304).

[0208] Since the decoding of the PDSCH data of HARQ process #1 fails, the control unit 55 of the terminal device 50 sends a NACK of HARQ process #1 to the base station device through the radio communication unit 51 (step S305). Next, the control unit 55 of the terminal device 50 stores the PDSCH data that failed to be decoded in the HARQ buffer 522a of HARQ process #1 in the storage unit 52 (step S306).

[0209] Next, the control unit (eg, control unit 23) of the base station device (eg, base station 20, base station 30) transmits PDSCH data of HARQ process #2 to the terminal device 50 through radio communication (eg, radio communication unit 21) (step S307).

[0210] In HARQ process #2, retransmission processing is disabled (HARQ feedback disabled). Therefore, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) does not keep the transmitted PDSCH data in the HARQ buffer of HARQ process #2 in the storage unit (e.g., storage unit 22) (step S308).

[0211] The control unit 55 of the terminal device 50 that has received the PDSCH data of the HARQ process #2 from the base station device decodes the PDSCH data. Here, it is assumed that the PDSCH data of the HARQ process #2 is not successfully decoded (step S309).

[0212] For HARQ process #2, retransmission processing is disabled in advance notification (step S301). Therefore, the control unit 55 of the terminal device 50 does not store the PDSCH data that failed to be decoded in the HARQ buffer of HARQ process #2 in the storage unit 52 (step S310). Even when the PDCCH that schedules the received PDSCH data indicates DL transmission, if the feedback of the corresponding HARQ process is disabled, the UE (terminal device 50) does not start drx-HARQ-RTT-TimerDL. That is, in this case, the drx-HARQ-RTT-TimerDL corresponding to HARQ process #2 is not started. In other words, when the PDCCH for the UE indicates DL transmission, the UE (terminal device 50) can implement an operation of determining whether the HARQ feedback in the corresponding HARQ process is disabled, and does not start drx-HARQ-RTT-TimerDL when the corresponding HARQ process is disabled, and starts drx-HARQ-RTT-TimerDL when the corresponding HARQ process is enabled.

[0213] The control unit (eg, control unit 23) of the base station device (eg, base station 20, base station 30) that receives the NACK of HARQ process #1 retransmits the PDSCH data to the terminal device 50 through radio communication (eg, radio communication unit 21) (step S311).

[0214] The control unit 55 of the terminal device 50 receiving the retransmission of the PDSCH data implements soft combining of the data stored in the HARQ buffer 522a of the HARQ process #1 and the retransmission data to decode the PDSCH data (step S312). Here, it is assumed that the PDSCH data is successfully decoded (step S313).

[0215] Due to the successful decoding of the PDSCH data, the control unit 55 of the terminal device 50 sends an ACK for HARQ process #1 to the base station device via the radio communication unit 51 (step S314). The control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) that receives the ACK for HARQ process #1 clears the data in the HARQ buffer of HARQ process #1 in the storage unit (e.g., storage unit 22) (step S315). Similarly, the control unit 55 of the terminal device 50 that sent the ACK for HARQ process #1 clears the data in the HARQ buffer 522a of HARQ process #1 (step S316).

[0216] <2-11. Example of HARQ disabling processing (uplink)>

[0217] Fig.12 is a sequence diagram showing an example of HARQ disabling processing according to an embodiment of the present disclosure. Specifically, as an example, Fig.12 FIG. 4 shows the HARQ feedback disabling in the uplink in units of HARQ processes. Fig.12 In the case of, HARQ process #1 is set to HARQ feedback enabled, and HARQ process #2 is set to HARQ feedback disabled.

[0218] like Fig.12 As shown in, first, similar to step S301 described above, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) notifies through radio communication (e.g., radio communication unit 21) to disable the predetermined HARQ process (step S401).

[0219] Next, the control unit (eg, control unit 23) of the base station device (eg, base station 20, base station 30) carries out DCI transmission (HARQ process #1) through radio communication (eg, radio communication unit 21) (step S402).

[0220] The control unit 55 of the terminal device 50 that received the DCI transmission implements PUSCH data transmission (HARQ process #1) through the radio communication unit 51 (step S403). The control unit 55 of the terminal device 50 holds the transmitted PUSCH data in the HARQ buffer 522a of the HARQ process #1 in the storage unit 52 (step S405).

[0221] The control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) that receives the PUSCH data transmission (HARQ process #1) from the terminal device 50 decodes the PUSCH data. Here, it is assumed that the PUSCH data of HARQ process #1 is not successfully decoded (step S404).

[0222] Due to the decoding failure of the PUSCH data of HARQ processing #1, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) keeps the PUSCH data that failed to be decoded in the HARQ buffer of HARQ processing #1 in the storage unit (e.g., storage unit 22) (step S406).

[0223] Next, the control unit (eg, control unit 23) of the base station device (eg, base station 20, base station 30) carries out DCI transmission (HARQ process #2) through radio communication (eg, radio communication unit 21) (step S407).

[0224] The control unit 55 of the terminal device 50 that has received the DCI transmission implements PUSCH data transmission (HARQ process #2) through the radio communication unit 51 (step S408). For HARQ process #2, retransmission processing is disabled in advance notification (step S401). Therefore, the control unit 55 of the terminal device 50 does not hold the transmitted PUSCH data in the HARQ buffer of HARQ process #2 in the storage unit 52 (step S411).

[0225] The control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) that receives the PUSCH data transmission (HARQ process #2) from the terminal device 50 decodes the PUSCH data. Here, it is assumed that the PUSCH data of HARQ process #2 is not successfully decoded (step S409).

[0226] In HARQ process #2, retransmission processing is disabled (HARQ feedback disabled). Therefore, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) does not keep the transmitted PUSCH data in the HARQ buffer of HARQ process #2 in the storage unit (e.g., storage unit 22) (step S410).

[0227] Next, the control unit (eg, control unit 23) of the base station device (eg, base station 20, base station 30) implements DCI transmission (retransmission request of HARQ process #1) through radio communication (eg, radio communication unit 21) (step S412).

[0228] The control unit 55 of the terminal device 50 that has received the DCI transmission (retransmission request of the HARQ process #1) implements PUSCH data transmission (retransmission of the HARQ process #1) through the radio communication unit 51 (step S413).

[0229] The control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) that receives the retransmission of the PUSCH data implements soft combination of the data stored in the HARQ buffer of HARQ process #1 and the retransmission data to decode the PUSCH data (step S414). Here, it is assumed that the PUSCH data is successfully decoded (step S415).

[0230] Due to the successful decoding of the PUSCH data, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) clears the data in the HARQ buffer of HARQ process #1 in the storage unit (e.g., storage unit 22) (step S416). Since there is no DCI transmission (retransmission request of HARQ process #1) from the base station device, the control unit 55 of the terminal device 50 clears the data in the HARQ buffer 522a of HARQ process #1 (step S417).

[0231] <2-12. Supporting feature compensation for HARQ disabling>

[0232] When HARQ feedback is disabled, retransmission cannot be performed even if a decoding error occurs, so it is important to reduce decoding errors during initial transmission. Therefore, the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) and the control unit 55 of the terminal device 50 reduce decoding errors by using the following techniques (A) to (C).

[0233] (A) Extending CQI while introducing HARQ feedback disabling

[0234] (B) Switching the MCS table to a table with low spectral efficiency while introducing HARQ feedback disabling

[0235] (C) When HARQ feedback disabling is enabled, switching to repeated transmission of the same transport block (TB) is implemented

[0236] The technique (A) is, for example, as follows: In the HARQ process in which HARQ feedback disabling is enabled, determination is made based on the extended CQI, and in the HARQ process in which HARQ feedback disabling is disabled, determination is made based on the legacy CQI.

[0237] The control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30) needs to know two types of CQI, namely, CQI (or traditional CQI) for HARQ enabling and CQI for HARQ disabling. As (a), the terminal device 50 returns a type of reference CQI (e.g., CQI for enabling, long-term CQI, etc.). The control unit (control unit 23) of the base station device (e.g., base station 20, base station 30) determines the MCS by estimating one CQI (e.g., CQI for enabling) from another CQI (e.g., CQI for disabling). Information that helps with the estimation (e.g., the offset value between the two types of CQI) can be reported in advance from the terminal device 50 to the base station device.

[0238] As (b), the terminal device 50 returns two types of CQI (CQI for enabling and CQI for disabling). The control unit (eg, control unit 23) of the base station device (eg, base station 20, base station 30) determines the MCS based on the CQI. Subsequently, the terminal device 50 feeds back two types of CQI indexes.

[0239] When both CQI for HARQ enabling and CQI for HARQ disabling are defined, target BLER is also defined for both. For example, the definition is implemented such that target BLER for CQI for HARQ enabling = 0.1, target BLER for CQI for HARQ disabling = 0.00001, and so on.

[0240] The CQI table is as follows.

[0241] - When both CQI for HARQ feedback enabling and CQI for HARQ feedback disabling are defined, both CQI tables need to be defined.

[0242] - Add a CQI table corresponding to the new target BLER.

[0243] - The calculation may be performed based on an existing CQI table. For example, a code rate obtained by multiplying the code rate of the existing table by a coefficient less than 1 is used.

[0244] - A value obtained by reducing the modulation in the existing table by one order may be used. For example, the value is obtained by reducing from 256QAM to 64QAM, from 64QAM to 16QAM, from 16QAM to QPSK, or from QPSK to BPSK. In the case of QPSK, QPSK is maintained.

[0245] The CQI calculation method is as follows.

[0246] -Assume that the CSI reference resources are as follows.

[0247] 1) Repeat the procedure for a predetermined number of times.

[0248] 2) When repeated multiple times, the redundancy version is set to [0,0,0,0], [0,2,3,1] or [0,3,0,3].

[0249] 3) Switching the calculation method for enabling or disabling HARQ processing. For example, changing the calculation method of CSI reference resources for each HARQ process.

[0250] 4) Add CQI offset. For example, when CQI offset=1 and the CQI calculation result is CQI=8, CQI=7 is reported.

[0251] Technique (B) is, for example, as follows: In a HARQ process in which HARQ feedback disabling is enabled, determination is performed based on an MCS table with lower spectral efficiency than other MCS tables. In a HARQ process in which HARQ feedback disabling is disabled, determination is performed based on an MCS table with higher spectral efficiency than other MCS tables.

[0252] When both the MCS for HARQ feedback enabling and the MCS for HARQ feedback disabling are defined, MCS tables are defined for both. For example, the MCS table for HARQ feedback enabling uses the existing MCS table 1 or 2, and the MCS table for HARQ feedback disabling uses the existing MCS table 3.

[0253] Alternatively, the calculation may be performed based on an existing MCS table. For example, a code rate obtained by multiplying a code rate of an existing table by a coefficient less than 1 may be used.

[0254] The value obtained by reducing the modulation in the existing table by one order can be used. For example, the value is obtained by reducing from 256QAM to 64QAM, from 64QAM to 16QAM, from 16QAM to QPSK, or from QPSK to BPSK. In the case of QPSK, QPSK is maintained.

[0255] When both MCS for HARQ enabling and MCS for HARQ disabling are defined, target BLER is also defined for both. For example, the definition is implemented such that target BLER for CQI with HARQ enabling = 0.1, target BLER for CQI with HARQ disabling = 0.00001, and so on.

[0256] The technique (C) is, for example, as follows. The retransmission transmission may be transmission in the same redundancy version (RV), or may be transmission in different RVs. In a HARQ process in which HARQ feedback disabling is enabled, repetitions of the same TB may be transmitted, and in a HARQ process in which HARQ feedback disabling is disabled, a single TB may be transmitted. In a HARQ process in which HARQ feedback disabling is enabled, the number of repeated transmissions of the same TB may be increased, and in a HARQ process in which HARQ feedback disabling is disabled, transmission may be implemented without increasing the number of repeated transmissions of the same TB.

[0257] <3-1. Modifications in the case where the number of HARQ processes can be increased>

[0258] Next, modifications in a case where the number of HARQ processes in the terminal device 50 can be increased (including HARQ feedback enabling after HARQ feedback disabling) will be described.

[0259] The terminal device 50, which can increase the number of HARQ processes and the buffer size associated with the HARQ buffer, sends capability information (UE radio access capability) to the non-terrestrial network (e.g., base station device) under the control of the control unit 55. The timing of sending the capability information may be in response to a query output from the RAN (satellite) immediately after the RRC is connected. Alternatively, the timing may be the time when the RRC setting is completed.

[0260] Here, the capability information includes the following information.

[0261] - Information on whether the number of HARQ processes can be increased

[0262] - Information about whether the buffer size can be increased

[0263] - Maximum supported size information for the number of HARQ processes

[0264] - Maximum supported size of the buffer

[0265] In the case of decreasing or increasing the number of HARQ processes, the control unit 55 of the terminal device 50 notifies information on whether to switch to increasing or decreasing the number of HARQ processes or returning the value to the default value. This notification includes explicit notification and implicit notification.

[0266] The explicit notification is, for example, a notification in system information, RRC signaling or MAC CE, or a notification in DCI or UCI. In the explicit notification, information for notifying the maximum number of handovers may be added. When implementing a HO from a TN to an NTN, the notification may be included in the HO command (RRCReconfiguration including ReconfigurationWithSync).

[0267] In implicit notification, the terminal device 50 decides whether to disable HARQ feedback based on system information or other information notified through RRC signaling. For example, in implicit notification, the terminal device 50 can use the following information in system information and the like to decide to disable.

[0268] - Location information of base station equipment and terminal equipment 50

[0269] - Propagation distance and propagation delay information between the base station device and the terminal device 50

[0270] - Altitude of base station equipment and terminal equipment 50

[0271] - The moving speed of the base station device and the terminal device 50

[0272] -Timing advance information

[0273] For example, when the timing advance is greater than a predetermined value, the control unit 55 of the terminal device 50 may increase the number of processes. When the timing advance is less than a predetermined value, the control unit 55 may reduce the number of HARQ processes or return the value to a default value.

[0274] The control unit 55 of the terminal device 50 may determine the number of HARQ processes based on the information about power control. For example, when the power control is greater than a predetermined value, the number of HARQ processes may be increased. When the power control is less than a predetermined value, the control unit 55 may reduce the number of HARQ processes or return the value to a default value.

[0275] The control unit 55 of the terminal device 50 may notify the number of HARQ processes. The notification includes explicit notification and implicit notification.

[0276] The explicit notification is, for example, a notification in system information, RRC signaling, or MAC CE. In the notification, there is a method of notifying the absolute value of the number of HARQ processes, or notifying the number of HARQ processes by switching the number of HARQ processes in multiple modes (switching in four modes such as 16, 32, 48, and 64).

[0277] Explicit notification includes notification in DCI or UCI. In the notification in DCI or UCI, a field for notifying the number of HARQ processes is added.

[0278] When implementing HO from TN to NTN, the notification may be included in the HO command (RRCReconfiguration including ReconfigurationWithSync).

[0279] In implicit notification, the terminal device 50 decides whether to disable HARQ feedback based on system information or other information notified through RRC signaling. For example, in implicit notification, the terminal device 50 can use the following information in system information and the like to decide to disable.

[0280] - Location information of base station equipment and terminal equipment 50

[0281] - Propagation distance and propagation delay information between the base station device and the terminal device 50

[0282] - Altitude of base station equipment and terminal equipment 50

[0283] - The moving speed of the base station device and the terminal device 50

[0284] -Timing advance information

[0285] For example, the control unit 55 of the terminal device 50 determines the number of HARQ processes according to the value of the timing advance. The control unit 55 of the terminal device 50 can determine the number of HARQ processes according to the value of the power control. The control unit 55 of the terminal device 50 can implement the notification using other physical information of the PDCCH (CORESET, search space, scrambling (DMRS, RNTI)).

[0286] In the control unit (eg, control unit 23) of the base station device (eg, base station 20, base station 30) and the control unit 55 of the terminal device 50, a method of notifying the HARQ process identifier after the number of HARQ processes increases or decreases is as follows.

[0287] (A) Case where the HARQ process identifier is explicitly notified

[0288] -Increase the number of bits in the notification field in the HARQ process of DCI.

[0289] -Use UCI to notify the HARQ process identifier.

[0290] (B) Case of implicit notification of HARQ process identifier

[0291] - Notification is implemented using other physical information of PDCCH (CORESET, search space, scrambling (DMRS, RNTI)).

[0292] - When DCI is notified through CORESET#A, the HARQ process identifier is read as #0 to 15, and when DCI is notified through CORESET#B, the HARQ process identifier is read as #(0 to 15)+16.

[0293] - Interpretation of the HARQ process identifier notified through DCI as the slot number (or SFN) changes.

[0294] For example, when DCI is notified through slot #0, the HARQ process identifier is read as #0 to 15, and when DCI is notified through slot #1, the HARQ process identifier is read as #(0 to 15) + 16. When DCI is notified through even-numbered slots, the HARQ process identifier is read as #0 to 15, and when DCI is notified through odd-numbered slots, the HARQ process identifier is read as #(0 to 15) + 16. Even numbers and odd numbers may be switched.

[0295] - Notification is implemented by reference signal sequence / port. For example, switching is implemented by initialization of the DMRS sequence notified by DCI. When the DMRS sequence is initialized to 0, the HARQ process identifier is read as #0 to 15, and when the DMRS sequence is initialized to 1, the HARQ process identifier is read as #(0 to 15)+16. Alternatively, switching can be implemented using antenna ports. For example, when transmission and reception are implemented through antenna port #0, the HARQ process identifier is read as #0 to 15, and when transmission and reception are implemented through antenna port #1, the HARQ process identifier is read as #(0 to 15)+16.

[0296] The DRX operation when the number of HARQ processes increases (including an increase (restoration) of the number of HARQ processes which can be fed back through HARQ feedback enabling) or decreases (including a decrease in the number of HARQ processes which can be fed back through HARQ feedback disabling) is as follows.

[0297] For example, the HARQRTTTimer (drx-HARQ-RTT-TimerDL, drx-HARQ-RTT-TimerUL) and drx-RetransmissionTimer (drx-RetransmissionTimerDL, drx-RetransmissionTimerUL) used in NTN communication may have different values ​​set by the RAN from the HARQRTTTimer (drx-HARQ-RTT-TimerDL, drx-HARQ-RTT-TimerUL) and drx-RetransmissionTimer (drx-RetransmissionTimerDL, drx-RetransmissionTimerUL) used in TN communication.

[0298] One HARQRTTTimer and one drx-RetransmissionTimer are associated with one HARQ process. Therefore, for example, if the number of HARQ processes used in NTN communication is greater than the number of HARQ processes used in TN communication, the frequency of starting / stopping of HARQRTTTimer and drx-RetransmissionTimer may also be higher. When the frequency of starting of drx-RetransmissionTimer increases, the frequency and time (e.g., active time) of PDCCH monitoring also increases, which may be inconvenient from the perspective of UE power saving.

[0299] Therefore, when the number of HARQ processes used in NTN communication is greater than the number of HARQ processes used in TN communication, at least the value of drx-RetransmissionTimer used in NTN communication can be set to be smaller than the value of drx-RetransmissionTimer used in TN communication. As a result, even when the number of HARQ processes used in NTN communication is greater than the number of HARQ processes used in TN communication, the total running period of drx-RetransmissionTimer to be monitored by the UE in PDCCH monitoring in NTN communication is still shorter than the simple product of the number of running HARQ processes in NTN communication and the value of drx-RetransmissionTimer used in TN communication. Therefore, the effect of the present embodiment can be applied while maintaining UE power saving.

[0300] In NTN communication, the difference between the timing at which a specific transmission signal transmitted from a transmission source should arrive at a reception source and the timing at which the transmission signal is actually received may be greater than in TN communication. The RTT between a base station (RAN) and a mobile station (UE) in NTN communication may be greater than the RTT in TN communication. These phenomena may be due to the length of the distance between the base station (RAN) and the mobile station (UE). Therefore, in order to absorb the deviation, the HARQRTTTimer and drx-RetransmissionTimer values ​​for NTN communication may be set to values ​​greater than those for TN communication.

[0301] The values ​​of HARQRTTTimer and drx-RetransmissionTimer used in NTN communication may be set separately from the values ​​of HARQRTTTimer and drx-RetransmissionTimer used in TN communication (for example, included in DRX-Config) and sent from the RAN to the UE, or may be pre-set in the UE as the default-DRX-config for NTN communication.

[0302] When the UE can communicate with a base station in TN communication and a base station in NTN communication in the RRC connected state (for example, in a case where a dual connection is set in which the base station for TN communication is an MN and the base station for NTN communication is an SN, or in a case in which the base station for TN communication is an anchor carrier and NTN communication is implemented with the base station for NTN communication), the values ​​of HARQRTTTimer and drx-RetransmissionTimer used in NTN communication and the values ​​of HARQRTTTimer and drx-RetransmissionTimer used in TN communication may be included in one RRCReconfiguration and sent.

[0303] It should be noted that the HARQRTTTimer and drx-RetransmissionTimer described above may be DL timers (eg, drx-HARQ-RTT-TimerDL and drx-RetransmissionTimerDL), UL timers (eg, drx-HARQ-RTT-TimerUL and drx-RetransmissionTimerUL), or both.

[0304] Each of the values ​​of the HARQRTTTimer and drx-RetransmissionTimer described above may be set to a value in units of subframes or a value in units of symbols. The values ​​of the HARQRTTTimer and drx-RetransmissionTimer described above may be set to a value in units of PDCCH cycles (pp). When the values ​​of the HARQRTTTimer and drx-RetransmissionTimer are values ​​in units of PDCCH cycles (pp), the values ​​of the HARQRTTTimer and drx-RetransmissionTimer that will actually be used by the UE may be derived by multiplying by a value corresponding to the UE's own coverage level (based on an indication of radio quality, such as a coverage enhancement level). The value corresponding to the UE's own coverage level may be sent from the RAN to the UE via RRC signaling (e.g., RRCReconfiguration).

[0305] <3-2. Other changes>

[0306] For example, in 3GPP Rel.15, the transmission timing of HARQ feedback (ACK / NACK) is specified as follows. In the case of DCI format 1_0, the DCI includes a PDSCH to HARQ timing indicator field, whose value is mapped to {1, 2, 3, 4, 5, 6, 7, 8}. When the reception of PDSCH (semi-persistent scheduling (SPS) PDSCH) ends in time slot n, the UE sends PUCCH (i.e., HARQ feedback (ACK / NACK)) in time slot n+k. Here, k is provided by the PDSCH to HARQ timing indicator field of DCI format 1_0. In the case of DCI format 1_1, the PDSCH to HARQ timing indicator field (0, 1, 2 or 3 bits) included in the DCI is mapped to the number of time slots in which the PUCCH in which the HARQ feedback will be sent, and indicates the value of the value provided by the dl-DataToUL-ACK of the RRC parameter to be referenced. That is, the value of dl-DataToUL-ACK corresponding to the bit combination indicated by the PDSCH to HARQ timing indicator field in DCI format 1_1 is used as k, and the UE sends PUCCH (i.e., HARQ feedback (ACK / NACK)) in time slot n+k. dl-DataToUL-ACK can be sent from the RAN to the UE in the semi-static notification described above.

[0307] The relationship between the PDSCH to HARQ timing indicator field used in the case of DCI format 1_1 and the value of dl-DataToUL-ACK is as shown in Table 1.

[0308] (Table 1)

[0309]

[0310]

[0311] In the case where the timing of dynamically disabling / enabling HARQ feedback (any of the conditions (a-1, a-2, b-1, b-2) described above) is earlier than the time slot n+k in which the PUCCH (i.e., HARQ feedback (ACK / NACK)) indicated by the PDSCH to HARQ timing indicator field included in the DCI will be sent, the UE (terminal device 50) can ignore the value of the PDSCH to HARQ timing indicator field. That is, HARQ feedback may not be implemented. More specifically, in the case where the subframe n+k or time slot n+k indicated by the condition (a-2) described above is earlier than the time slot n+k in which the PUCCH (i.e., HARQ feedback (ACK / NACK)) indicated by the PDSCH to HARQ timing indicator field included in the DCI will be sent, the UE (terminal device 50) can ignore the value of the PDSCH to HARQ timing indicator field. In other words, in the case where the subframe n+k or time slot n+k indicated by the condition (a-2) described above is earlier than the time slot n+k in which the PUCCH (i.e., HARQ feedback (ACK / NACK)) indicated by the PDSCH to HARQ timing indicator field included in the DCI is to be sent, the UE (terminal device 50) is not expected to send the PUCCH (i.e., HARQ feedback (ACK / NACK)) in the time slot n+k derived from the PDSCH to HARQ timing indicator field. In this case, the notification indicating the timing (e.g., n+k) for implementing HARQ feedback disabling and the PDSCH to HARQ timing indicator field may be included in the same DCI, or may be included in separate DCIs.

[0312] In the embodiments of the present disclosure, the enable / disable target is described as the HARQ feedback, but the enable / disable target may be the HARQ process itself, or other processes other than the HARQ feedback in the HARQ process.

[0313] The enabling / disabling described above may also be referred to as activation / deactivation. The control device that controls the management device 10, the base stations 20, 30, 40 or the terminal device 50 of this embodiment may be implemented by a dedicated computer system or a general-purpose computer system.

[0314] For example, a communication program for performing the operations described above (e.g., initial access processing, HARQ processing, etc.) is stored in a computer-readable recording medium such as an optical disk, a semiconductor memory, a magnetic tape, or a flexible disk and distributed. For example, the program is installed in a computer, and the processing described above is implemented to configure a control device. At this time, the control device may be a device (e.g., a personal computer) outside the management device 10, the base station 20, 30, 40, or the terminal device 50. The control device may be a device (e.g., a control unit 13, a control unit 23, or a control unit 55) inside the base station 20, 30, 40, or the terminal device 50.

[0315] The communication program described above can be stored in a disk device included in a server device on a network such as the Internet, so that the communication program can be downloaded to a computer. The functions described above can be implemented by the cooperation of an operating system (OS) and application software. In this case, other parts other than the OS can be stored in a medium and distributed, or other parts other than the OS can be stored in a server device and downloaded to a computer.

[0316] In each of the processes described in the previous embodiments, all or part of the processes described as being automatically implemented may be implemented manually, or all or part of the processes described as being manually implemented may be automatically implemented by known methods. Unless otherwise specified, the processing procedures, specific names, and information including various data and parameters shown in the previous text and drawings may be changed arbitrarily. For example, the various types of information shown in each figure are not limited to the information shown.

[0317] Each component of each device shown is a functional concept and does not necessarily have to be physically configured as shown in the figure. That is, the specific form of distribution / integration of each device is not limited to the form shown in the figure, and all or part of the device can be distributed / integrated in any unit in terms of function or physics according to various loads and usage conditions, etc.

[0318] The previously described embodiments and modifications may be appropriately combined as long as the processing contents do not conflict with each other. The order of each step shown in the flowchart or sequence diagram of each embodiment described previously may be appropriately modified.

[0319] <4. Conclusion>

[0320] As described above, according to one embodiment of the present disclosure, the terminal device 50 can receive a notification of disabling feedback for retransmission in HARQ and disable feedback for retransmission (HARQ feedback disabling). This can help eliminate the shortage of the number of HARQ processes and can help suppress the deterioration of communication quality.

[0321] Although the embodiments of the present disclosure are described above, the technical scope of the present disclosure is not limited to the exact embodiments described above, and various modifications may be made without departing from the gist of the present disclosure. Components of different embodiments and modifications may be appropriately combined.

[0322] The effects in each embodiment described in this specification are merely examples and not limitations, and there may be other effects.

[0323] It should be noted that the technology of the present invention may also have the following configurations.

[0324] (1) A terminal device comprising:

[0325] Communication unit and control unit,

[0326] Wherein, the control unit is configured as:

[0327] receiving, by the communication unit, disabling information of hybrid automatic repeat request (HARQ) feedback, and

[0328] recognizing that one or more HARQ feedbacks indicated by the HARQ feedback disabling information are disabled, and

[0329] The disabling information of the HARQ feedback is set for each cell, each beam, each component carrier, each bandwidth part (BWP), each user equipment (UE) or each HARQ process.

[0330] (2) The terminal device according to (1),

[0331] The disabling information of the HARQ feedback is sent in any one of the semi-static notification, the dynamic notification, and the combination of the semi-static notification and the dynamic notification from the base station device.

[0332] (3) The terminal device according to (2),

[0333] The semi-static notification is a signal notification of Radio Resource Control (RRC).

[0334] (4) A terminal device according to (2) or (3),

[0335] The dynamic notification is a notification of downlink control information (DCI) or uplink control information (UCI).

[0336] (5) The terminal device according to any one of (1) to (4),

[0337] The disabling information fed back by the HARQ includes the number of disabled HARQ processes among the one or more HARQ processes.

[0338] (6) The terminal device according to any one of (1) to (5),

[0339] The disabling information fed back by the HARQ includes identification information of a disabled HARQ process among one or more HARQ processes.

[0340] (7) The terminal device according to any one of (1) to (6),

[0341] The control unit switches compensation of the error rate characteristic by switching from a HARQ process in which retransmission is not disabled to a HARQ process in which retransmission is disabled according to the disablement information based on the HARQ feedback.

[0342] (8) The terminal device according to (7),

[0343] Therein, in response to switching to the HARQ process in which retransmission is disabled, the control unit makes the compensation of the error rate characteristic lower than the case of the HARQ process in which retransmission is not disabled.

[0344] (9) The terminal device according to any one of (1) to (8),

[0345] According to the increase or decrease in the number of the one or more HARQ processes, the control unit sends information about the increase or decrease through the communication unit.

[0346] (10) A base station device, comprising:

[0347] Communication unit and control unit,

[0348] Wherein, the control unit is configured as:

[0349] transmitting, by the communication unit, disabling information for hybrid automatic repeat request (HARQ) feedback, and

[0350] identifying that one or more HARQ processes indicated by the disabling information of the HARQ feedback are disabled, and

[0351] The disabling information of the HARQ feedback is set for each cell, each beam, each component carrier, each bandwidth part (BWP), each user equipment (UE) or each HARQ process.

[0352] (11) The base station device according to (10),

[0353] The control unit sends the disabling information of the HARQ feedback in any one of the semi-static notification, the dynamic notification and the combination of the semi-static notification and the dynamic notification.

[0354] (12) The base station device according to (11),

[0355] The semi-static notification is a signal notification of Radio Resource Control (RRC).

[0356] (13) The base station device according to (11) or (12),

[0357] The dynamic notification is a notification of downlink control information (DCI) or uplink control information (UCI).

[0358] (14) The base station device according to any one of (10) to (13),

[0359] The disabling information of the HARQ feedback includes the number of disabled HARQ processes among the one or more HARQ processes.

[0360] (15) The base station device according to any one of (10) to (14),

[0361] The disabling information of the HARQ feedback includes identification information of the disabled HARQ process among the one or more HARQ processes.

[0362] (16) The base station device according to any one of (10) to (15),

[0363] The control unit switches compensation of the error rate characteristic by switching from a HARQ process in which retransmission is not disabled to a HARQ process in which retransmission is disabled according to the disablement information based on the HARQ feedback.

[0364] (17) The base station device according to (16),

[0365] Therein, in response to switching to the HARQ process in which retransmission is disabled, the control unit makes the compensation of the error rate characteristic lower than the case of the HARQ process in which retransmission is not disabled.

[0366] (18) A method for controlling a terminal device, the method comprising:

[0367] receiving, by the communication unit, disabling information of hybrid automatic repeat request (HARQ) feedback;

[0368] identifying that one or more HARQ processes indicated by the disabling information of the HARQ feedback are disabled; and

[0369] Disabling information of HARQ feedback is set for each cell, each beam, each component carrier, each bandwidth part (BWP), each user equipment (UE), or each HARQ process.

[0370] (19) A method for controlling a base station device, the method comprising:

[0371] Sending, by the communication unit, disabling information of hybrid automatic repeat request (HARQ) feedback;

[0372] identifying that one or more HARQ processes indicated by the disabling information of the HARQ feedback are disabled; and

[0373] Disabling information of HARQ feedback is set for each cell, each beam, each component carrier, each bandwidth part (BWP), each user equipment (UE), or each HARQ process.

[0374] Reference numerals list

[0375] 1 Communication system

[0376] 10. Manage Devices

[0377] 11 Communication unit

[0378] 12, 22, 52 storage units

[0379] 13, 23, 55 Control unit

[0380] 20, 30, 40 base stations

[0381] 21, 51 Radio communication unit

[0382] 50 Terminal equipment

[0383] 53 Network Communication Unit

[0384] 54 Input and output units

[0385] 211 Receiving Processing Unit

[0386] 211a, 511a radio receiving unit

[0387] 211b, 511b demultiplexing unit

[0388] 211c, 511c demodulation unit

[0389] 211d, 511d decoding unit

[0390] 212 Send processing unit

[0391] 212a, 512a coding unit

[0392] 212b, 512b modulation unit

[0393] 212c, 512c multiplexing unit

[0394] 212d, 512d radio transmission unit

[0395] 213, 513 antenna

[0396] 521, 522, 523 storage segments

[0397] 521a, 522a, 523a HARQ buffer

[0398] ABP1 Aerial Platform

[0399] C2 Cellular

[0400] CN Core Network

[0401] D1 Radius

[0402] PN Public Network

[0403] R1 Angle

[0404] RAN Radio Access Network

[0405] SBP1, SBP2 Space Platform

[0406] TN1, TN2 land network

Claims

1. A terminal device, comprising: a radio communication unit and a control unit, wherein the radio communication unit is configured to perform radio communication with one or more radio communication devices, Wherein, the control unit is configured as: receiving, by the radio communication unit, disabling information of hybrid automatic repeat request HARQ feedback transmitted in any one of a semi-static notification, a dynamic notification, and a combination of the semi-static notification and the dynamic notification from the base station device, and recognizing that one or more HARQ feedbacks indicated by the HARQ feedback disabling information are disabled, and The HARQ feedback disabling information is set for each cell, each beam, each component carrier, each bandwidth part BWP or each user equipment UE. The terminal device decides whether to disable HARQ feedback based on the propagation distance and propagation delay information between the base station device and the terminal device in the case of semi-static notification, and disables HARQ feedback when it is determined that the HARQ processing has been exhausted or may be exhausted in the case of dynamic notification.

2. The terminal device according to claim 1, in, The semi-static notification is a signal notification of the radio resource control RRC.

3. The terminal device according to claim 1, in, The dynamic notification is notification of downlink control information DCI or uplink control information UCI.

4. The terminal device according to claim 1, in, The disabling information of the HARQ feedback includes the number of disabled HARQ processes among the one or more HARQ processes.

5. The terminal device according to claim 1, in, The disabling information of the HARQ feedback includes identification information of a disabled HARQ process among one or more HARQ processes.

6. The terminal device according to claim 1, in, The control unit switches compensation of the error rate characteristic according to switching from the HARQ process in which retransmission is not disabled to the HARQ process in which retransmission is disabled based on the disablement information of the HARQ feedback.

7. The terminal device according to claim 6, in, In response to switching to the HARQ process in which retransmission is disabled, the control unit makes the compensation of the error rate characteristic higher than the case of the HARQ process in which retransmission is not disabled.

8. The terminal device according to claim 1, in, According to the increase or decrease in the number of the one or more HARQ processes, the control unit transmits information on the increase or decrease through the communication unit.

9. A base station device, comprising: a radio communication unit and a control unit, wherein the radio communication unit is configured to perform radio communication with one or more radio communication devices, Wherein, the control unit is configured as: transmitting, by the radio communication unit, disabling information of a hybrid automatic repeat request HARQ feedback transmitted in any one of a semi-static notification, a dynamic notification, and a combination of the semi-static notification and the dynamic notification, and identifying that one or more HARQ processes indicated by the disabling information of the HARQ feedback are disabled, and The HARQ feedback disabling information is set for each cell, each beam, each component carrier, each bandwidth part BWP or each user equipment UE. In the case of semi-static notification, one or more radio communication devices decide whether to disable HARQ feedback based on the propagation distance and propagation delay information between the base station device and the one or more radio communication devices, and in the case of dynamic notification, disable HARQ feedback when it is determined that the HARQ processing has been exhausted or may be exhausted.

10. The base station device according to claim 9, in, The semi-static notification is a signal notification of the radio resource control RRC.

11. The base station device according to claim 9, in, The dynamic notification is notification of downlink control information DCI or uplink control information UCI.

12. The base station device according to claim 9, in, The disabling information of the HARQ feedback includes the number of disabled HARQ processes among the one or more HARQ processes.

13. The base station device according to claim 9, in, The disabling information of the HARQ feedback includes identification information of the disabled HARQ process among the one or more HARQ processes.

14. The base station device according to claim 9, in, The control unit switches compensation of the error rate characteristic according to switching from the HARQ process in which retransmission is not disabled to the HARQ process in which retransmission is disabled based on the disablement information of the HARQ feedback.

15. The base station device according to claim 14, in, In response to switching to the HARQ process in which retransmission is disabled, the control unit makes the compensation of the error rate characteristic higher than the case of the HARQ process in which retransmission is not disabled.

16. A method for controlling a terminal device, the method comprising: receiving, by the radio communication unit, disabling information of a hybrid automatic repeat request HARQ feedback sent in any one of a semi-static notification, a dynamic notification, and a combination of the semi-static notification and the dynamic notification; identifying that one or more HARQ processes indicated by the disabling information of the HARQ feedback are disabled; and The HARQ feedback disabling information is set for each cell, each beam, each component carrier, each bandwidth part BWP or each user equipment UE. The terminal device decides whether to disable HARQ feedback based on the propagation distance and propagation delay information between the base station device and the terminal device in the case of semi-static notification, and disables HARQ feedback when it is determined that the HARQ processing has been exhausted or may be exhausted in the case of dynamic notification.

17. A method for controlling a base station device, the method comprising: performing radio communication with one or more radio communication devices via a radio communication unit; transmitting, by the radio communication unit, disabling information of a hybrid automatic repeat request HARQ feedback transmitted in any one of a semi-static notification, a dynamic notification, and a combination of the semi-static notification and the dynamic notification; identifying that one or more HARQ processes indicated by the disabling information of the HARQ feedback are disabled; and The HARQ feedback disabling information is set for each cell, each beam, each component carrier, each bandwidth part BWP or each user equipment UE. In the case of semi-static notification, one or more radio communication devices decide whether to disable HARQ feedback based on the propagation distance and propagation delay information between the base station device and the one or more radio communication devices, and in the case of dynamic notification, disable HARQ feedback when it is determined that the HARQ processing has been exhausted or may be exhausted.

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