Terminal device, base station device, method for controlling terminal device, and method for controlling base station device

Abstract

Such a terminal device (50) includes a communication unit (51) and a control unit (55). The control unit (55) transmits or receives predetermined data a predetermined number of times via the communication unit (51). The control unit (55) also transmits or receives predetermined data a predetermined number of times in cooperation with other terminal devices.

Description

Technical Field

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

[0002] In the 3rd Generation Partnership Project (3GPP), radio access schemes and wireless networks for cellular mobile communications have been reviewed (hereinafter also referred to as Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Advanced Pro (LTE-A Pro), New Radio (NR), New Radio Access Technology (NRAT), Evolved Universal Terrestrial Radio Access (EUTRA), or Further EUTRA (FEUTRA)).

[0003] As a radio access scheme for the next generation of LTE, NR is a radio access technology (RAT) different from LTE. NR is an access technology capable of handling various usage scenarios, including enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low-latency communication (URLLC). NR is reviewed for the purpose of a technical framework corresponding to usage scenarios, request conditions, placement scenarios, etc. in such usage scenarios.

[0004] In addition, in NR, research on non-terrestrial networks (NTN) that provide wireless networks from devices floating in the air or in space has been started in response to increasing demands such as wide-area coverage and connection stability. In non-terrestrial networks, wireless networks are provided to terminal devices via satellite stations and aircraft. In addition, in non-terrestrial networks, the use of the same radio access scheme as in the radio access scheme in terrestrial networks promotes integrated operation between terrestrial networks and non-terrestrial networks. Low Earth Orbit satellites, Medium Earth Orbit satellites, etc. in non-terrestrial networks move at high speed in the sky, so handover may occur frequently. Therefore, in non-terrestrial networks, handover may occur during the retransmission of data. Non-Patent Document 1 discloses a technique related to handover in non-terrestrial networks.

[0005] Citation List

[0006] Non-Patent Document

[0007] Non-Patent Document 1: R2-1910452, Intel Corporation, "Conditional Handover for Non-Terrestrial Networks," 3GPP TSG RAN2 Meeting #107, Prague, Czech Republic, August, 2019. Summary of the Invention

[0008] Technical problem

[0009] Here, among non-ground stations, when viewed from a terminal on the ground, non-ground stations such as medium Earth orbit satellites, low Earth orbit satellites, and high altitude platform stations (HAPS) appear to move at high speed in the sky. In particular, low Earth orbit satellites move at high speed in the sky, and the cells formed by low Earth orbit satellites on the ground also move at high speed. Therefore, due to the high-speed movement of the cells, cell handover (handover) may occur during data transmission / reception, which may lead to failure of data transmission / reception.

[0010] Therefore, an object of the present disclosure is to provide a terminal device, a base station device, a control method of a terminal device, and a control method of a base station device that can reduce the failure of data transmission / reception caused by the occurrence of handover.

[0011] Solution to the problem

[0012] The terminal device includes a communication unit and a control unit. The control unit transmits or receives predetermined data a predetermined number of times via the communication unit. In addition, the control unit transmits or receives predetermined data a predetermined number of times in cooperation with other terminal devices. Description of the drawings

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

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

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

[0016] Figure 4 is a diagram showing an example of a cell composed of satellite stations.

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

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

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

[0020] Figure 8 is a flowchart showing an example of initial connection processing.

[0021] Figure 9 It is a sequence diagram showing the processing of the terminal device and the base station device before and after the handover occurring during data transmission.

[0022] Figure 10 It is a diagram showing the situation where multiple terminal devices cooperate to transmit data.

[0023] Figure 11 It is a diagram showing the situation where multiple terminal devices cooperate to transmit data.

[0024] Figure 12 It is a diagram showing the situation where multiple terminal devices cooperate to receive data.

[0025] Figure 13 It is a flowchart showing the process of the processing to be executed by the terminal device according to the embodiment. Detailed Description of the Embodiment

[0026] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In each of the following embodiments, the same parts are denoted by the same reference numerals, and the repeated description thereof will be omitted.

[0027] In addition, in this specification and the drawings, in some cases, multiple components having substantially the same functional structure are distinguished by attaching different numbers after the same reference numeral. In one example, multiple components having substantially the same functional structure are distinguished as needed, such as terminal devices 501, 502, and 503. However, unless it is necessary to particularly distinguish each of the multiple components having substantially the same functional structure, only the same reference numeral is attached. In one example, unless it is particularly necessary to distinguish terminal devices 501, 502, and 503, terminal devices 501, 502, and 503 are simply referred to as terminal device 50.

[0028] In addition, the present disclosure will be described in the order of the items indicated below.

[0029] 1. Introduction

[0030] 2. Embodiment

[0031] 2-1. Overall Structure of the Communication System

[0032] 2-2. Structure of the Management Device

[0033] 2-3. Structure of the Base Station

[0034] 2-4. Structure of the Terminal Device

[0035] 2-5. Initial Connection Processing

[0036] 2-6. Example of HARQ process

[0037] 2-7. Overview of embodiments

[0038] 2-8. Determination process of cooperative terminals

[0039] 2-9. Relationship between cooperative terminals

[0040] 2-10. Transmission signal processing

[0041] 2-11. Data

[0042] 3. Modification example

[0043] 4. Conclusion

[0044] <1. Introduction>

[0045] 3GPP considers radio access technologies such as LTE and NR. LTE and NR are types of cellular communication technologies and can achieve mobile communication of terminal devices by arranging multiple areas covered by base stations in the form of cells. In addition, as used herein, the term "LTE" includes LTE-Advanced (LTE-A), LTE-Advanced Pro (LTE-A Pro), and Evolved Universal Terrestrial Radio Access (EUTRA). Further, as used herein, the term "NR" includes New Radio Access Technology (NRAT) and Further EUTRA (FEUTRA).

[0046] NR is the next-generation (fifth-generation) radio access technology (RAT) of LTE. NR is a radio access technology capable of supporting various usage scenarios, including enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and URLLC. NR is reviewed for the purpose of a technical framework corresponding to usage scenarios, request conditions, placement scenarios, etc. in these usage scenarios.

[0047] For example, as one of the usage scenarios of NR that requires wide-area coverage, connection stability, etc., research on non-terrestrial networks (NTN) has been started. In a non-terrestrial network, a wireless network is planned to be provided for terminal devices via base stations other than terrestrial stations (such as satellite stations or aircraft stations). Base stations other than terrestrial stations are called non-terrestrial stations or non-terrestrial base stations. The wireless network provided by terrestrial stations is called a terrestrial network (TN). Using the same radio access scheme for both the terrestrial network and the non-terrestrial network can achieve integrated operation of the terrestrial network and the non-terrestrial network.

[0048] In addition, in the embodiments of the present disclosure, a ground station (also referred to as a ground base station) represents a base station (including a relay station) installed on the ground. The term "ground" not only represents the ground (land), but also represents the ground in a broad sense, including underground, over water, and underwater.

[0049] In addition, in some embodiments, application examples of NTN will be described as one of the usage scenarios of NR. However, the applications of these embodiments are not limited to NTN, and the embodiments can be applied to other technologies and usage scenarios (e.g., URLLC).

[0050] <2. Embodiments>

[0051] Now, the communication system 1 according to the present embodiment will be described. The communication system 1 includes a non-ground station and uses a non-ground network for a terminal device to provide wireless communication. In addition, the communication system 1 can use a ground network to provide wireless communication. Furthermore, the non-ground network and the ground network provided in the communication system 1 are not limited to wireless networks using a radio access scheme specified by NR. The non-ground 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), and Code Division Multiple Access 2000 (cdma2000).

[0052] Note that 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 radio interface to the relay station. In addition, the concept of a base station includes not only a structure equipped with the functions of a base station but also the devices installed in that structure. In one example, the structure is a building, such as a tower building, a house, a steel tower, a railway station facility, an airport facility, a port facility, and a stadium. In addition, the concept of a structure includes not only buildings but also non-building structures, such as tunnels, bridges, dams, fences, and steel columns, or also includes facilities such as cranes, gates, and windmills. In addition, the concept of a structure includes not only structures on the ground (land) or underground structures but also structures on water (such as docks and large floating bodies (very large floating structures)) or underwater structures (such as ocean observation facilities). In addition, a base station may be constituted by a set of physical or logical devices. For example, in an embodiment of the present disclosure, a base station is classified into a plurality of devices of a baseband unit (BBU) and a radio unit (RU), and may be interpreted as a set of these plurality of devices. In addition to or instead of this, in an embodiment of the present disclosure, a base station may be one or both of the BBU and the RU. The BBU and the RU may be connected to a predetermined interface (e.g., eCPRI). In addition to or instead of this, the RU may be referred to as a remote radio unit (RRU) or a radio DoT (RD). In addition to or instead of this, the RU may support gNB-DU, which will be described later. In addition to or instead of this, the BBU may support gNB-CU, which will be described later. In addition to or instead of this, the RU may be a device integrally formed with an antenna. The antenna of the base station (e.g., an antenna integrally formed with the RU) may adopt an advanced antenna system and support MIMO (e.g., FD-MIMO) and beamforming. In the advanced antenna system, the antenna of the base station (e.g., an antenna integrally formed with the RU) may include, for example, 64 transmit antenna ports and 64 receive antenna ports.

[0053] In addition, the base station may be a base station configured to be movable. In one example, the base station may be a device installed in a moving body or the moving body itself. The moving body may be a mobile terminal (such as a smart phone), a moving body moving on the ground (land) (e.g., a vehicle such as a car, a bus, a truck, a train, and a linear motor train), or a moving body moving underground (e.g., in a tunnel) (e.g., a subway). In addition, the moving body may be a moving object moving on water (e.g., a ship such as a passenger ship, a cargo ship, and an air-cushion vehicle) or a moving body moving underwater (e.g., a submersible such as a submarine, a submersible, and an unmanned submersible). In addition, the moving body may be a moving object moving in the atmosphere (e.g., an aircraft such as an airplane, a dirigible, and a drone) or a space moving body moving outside the atmosphere (e.g., an artificial celestial body such as an artificial satellite, a spaceship, a space station, and a space probe).

[0054] Multiple base stations can be connected to each other. One or more base stations can be included in a Radio Access Network (RAN). In other words, a base station can be simply referred to as a RAN, a RAN node, an Access Network (AN), or an AN node. The RAN in LTE is called the Evolved Universal Terrestrial RAN (EUTRAN). The RAN in NR is called the New Radio RAN (NGRAN). The RAN in W-CDMA (UMTS) is called the Universal Terrestrial RAN (UTRAN). An LTE base station is called an evolved Node B (eNodeB) or eNB. In other words, EUTRAN includes one or more eNodeBs (eNBs). Additionally, an NR base station is also called a gNodeB or gNB. In other words, NGRAN contains one or more gNBs. Additionally, EUTRAN can include a gNB (en-gNB) connected to the core network (EPC) in the LTE communication system (EPS). Similarly, NGRAN can include an ng-eNB connected to the core network 5GC in the 5G communication system (5GS). In addition to or instead of this, in the case where the base station is an eNB, gNB, etc., it can be called 3GPP access. In addition to or instead of this, in the case where the base station is a Wireless Access Point, it can be called non-3GPP access. In addition to or instead of this, the base station can be an optical pendant device called a Remote Radio Head (RRH). In addition to or instead of this, in the case where the base station is a gNB, the base station can be called a combination of the above gNB Central Unit (CU) and gNB Distributed Unit (DU) or any one of them. The gNB Central Unit (CU) hosts multiple upper layers (e.g., RRC, SDAP, PDCP) in the access stratum for communication with the UE. On the other hand, the gNB-DU hosts multiple lower layers (e.g., RLC, MAC, PHY) in the access stratum. In other words, among the messages or information to be described later, RRC signaling (quasi-static notification) can be generated by the gNB CU, while DCI (dynamic notification) can be generated by the gNB-DU. Or alternatively, among the RRC configurations (quasi-static notifications), for example, some configurations (such as the IE: cell Group Config) can be generated by the gNB-DU, and the remaining configurations can be generated by the gNB-CU. These configurations can be sent and received through the F1 interface to be described later. The base station can be configured to be able to communicate with other communication base stations. For example, in the case where multiple base station devices are eNBs or a combination of eNBs and en-gNBs, the base stations can be connected through the X2 interface. In addition to or instead of this, in the case where multiple base stations are gNBs or a combination of ng-eNBs and gNBs, these devices can be connected through the Xn interface. In addition to or instead of this, in the case where multiple base stations are a combination of the gNB Central Unit (CU) and gNB Distributed Unit (DU), these devices can be connected through the above F1 interface.Messages or information (RRC signaling or DCI information) that will be described later can be transmitted among multiple base stations (e.g., via the X2, Xn, and F1 interfaces).

[0055] In addition, in LTE and NR, a terminal device (also referred to as a mobile station, mobile station device, or terminal) can be referred to as a user equipment (UE). Alternatively, the terminal device can be referred to as a mobile station (MS) or a wireless transmit / receive unit (WTRU). Furthermore, a terminal device is a type of wireless communication device and is also referred to as a mobile station, mobile station equipment, or terminal. In embodiments of the present disclosure, the concept of a terminal device includes not only portable terminal devices (such as mobile terminals) but also, in one example, devices installed in a structure or a moving body.

[0056] <2-1. Overall Structure of the Communication System>

[0057] Figure 1 FIG. is a diagram showing an example of the structure of a communication system 1 according to an embodiment of the present disclosure. The communication system 1 includes a management device 10, a non-ground base station (hereinafter simply referred to as a base station) 20, a ground base station (hereinafter simply referred to as a base station) 30, a relay device (hereinafter simply referred to as a base station) 40, and a terminal device 50. By operating each wireless communication device constituting the communication system 1 in cooperation with each other, the communication system 1 provides a wireless network that allows mobile communication for users. A wireless communication device is a device having a wireless communication function and corresponds to Figure 1 the base stations 20, 30, and 40 and the terminal device 50 in the example of

[0058] The communication system 1 may include multiple management devices 10, base stations 20, 30, 40, and terminal devices 50. In Figure 1 the example of , the communication system 1 includes management devices 101, 102, etc. as the management device 10. In addition, the communication system 1 includes base stations 201, 202, etc. as the base station 20, and includes base stations 301 and 302, etc. as the base station 30. In addition, 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 of the embodiments of the present disclosure is not limited to non-terrestrial communication (NTN). In other words, the communication system does not necessarily include non-ground stations.

[0059] The management device 10 is a device that manages a wireless network. For example, the management device 10 is a device that functions as a Mobility Management Entity (MME) or an Access and Mobility Management Function (AMF). The MME is connected to the EUTRAN via the S1 interface, controls the non-access stratum (NAS) signaling between the EUTRAN and the UE, and manages the mobility of the UE. The AMF is connected to the NGRAN via the NG interface, controls the non-access stratum (NAS) signaling between the NGRAN and 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 the plurality of base stations 20 and the plurality of base stations 30. The management device 10 manages the communication between the base stations 20 and 30. The core network transmits user data between a Packet Data Network (PDN) or a Data Network (DN) and the RAN and a control plane (C-plane) node (such as the management device 10). The core network may include a user plane (U-plane) node. The U-plane node in the EPC may include a Serving Gateway (S-GW) and a PDN Gateway (P-GW). The U-plane node in the 5GC may include a U-plane Function (UPF). For example, the management device 10 manages the location of the terminal device 50 (UE) in the communication system 1 for each terminal device 50 in units of areas including a plurality of cells (e.g., a tracking area, a RAN notification area). It should be noted that the management device 10 may know and manage, for each terminal device 50, the base station (or cell) to which the terminal device 50 is connected, the communication area of the base station (or cell) where the terminal device 50 is located, etc., in units of cells.

[0060] The base station 20 is a base station that communicates with the terminal device 50 wirelessly. In Figure 1 the example, the base station 201 connected to the base station 401 can also communicate with the terminal device 50 wirelessly via the base station 401. In the present embodiment, the base station 20 is a base station that can float in the air or in space. For example, the base station 20 is a non-ground station device such as an aircraft station or a satellite station.

[0061] An aircraft station is a wireless communication device capable of floating in the atmosphere, such as an aircraft for example. The aircraft station can be, for example, a device installed on an aircraft or the like, or the aircraft itself. Furthermore, the concept of an aircraft not only includes heavy aircraft (such as airplanes and gliders), but also includes light aircraft (such as balloons and airships). Additionally, the concept of an aircraft not only includes heavy and light aircraft, but also includes rotary-wing aircraft, such as helicopters and autogyros. Moreover, the aircraft station (or the aircraft equipped with the aircraft station) can be an unmanned aircraft, such as a drone. Additionally, the concept of an unmanned aircraft also includes an unmanned aircraft system (UAS) and a tethered unmanned aerial system (tethered UAS). Further, the concept of an unmanned aircraft includes lighter-than-air (LTA) UAS and heavier-than-air (HTA) UAS. Additionally, the concept of an unmanned aircraft also includes a high-altitude UAS platform (HAP). Additionally, in the case where the aircraft station is used as a UE, the aircraft station can be an aerial UE.

[0062] A satellite station is a wireless communication device capable of floating outside the atmosphere. The satellite station can be a device installed on a spacecraft (such as an artificial satellite) or the spacecraft itself. The satellite serving as the satellite station can be any of a low Earth orbit (LEO) satellite, a medium Earth orbit (MEO) satellite, a geostationary Earth orbit (GEO) satellite, and a highly elliptical orbit (HEO) satellite. The satellite station can understandably be a device installed on a low Earth orbit satellite, a medium Earth orbit satellite, a geostationary Earth orbit satellite, or a highly elliptical orbit satellite.

[0063] Base station 30 is a base station that communicates wirelessly with terminal device 50. In Figure 1 the example, base station 301 connected to base station 402 can also communicate wirelessly with terminal device 50 via base station 402. Base station 30 can be a base station on a structure located on the ground, or can be a base station arranged on a moving body moving on the ground. For example, base station 30 is an antenna arranged on a structure (such as a building) and a signal processing device connected to the antenna. Of course, base station 30 can be the structure or the moving body itself.

[0064] Base station 40 is a device that serves as a relay station for a base station. Base station 40 is a type of base station. Base station 40 forwards the communication between base station 20 and terminal device 50 or the communication between base station 30 and terminal device 50. Base station 40 can be a ground station or a non-ground station. Base station 40 can form a radio access network RAN together with base stations 20 and 30. It should be noted that hereinafter, base stations 20, 30, and 40 may be collectively referred to as base stations or base station devices.

[0065] In one example, the terminal device 50 is a mobile phone, a smart device (smartphone or tablet computer), a personal digital assistant (PDA), or a personal computer. Additionally, the terminal device 50 can be a machine-to-machine (M2M) device or an Internet of Things (IoT) device (e.g., which may be referred to as an MTC UE, an NB-IoT UE, or a Cat.M UE). Additionally, the terminal device 50 can be a wireless communication device installed in a moving body or the moving body itself. Further, the terminal device 50 can be a relay station for relaying satellite communication or a base station for receiving satellite communication. The terminal device 50 is compatible with both a terrestrial network and a non-terrestrial network. Thus, the terminal device 50 can communicate not only with a terrestrial station device (such as the base station 30) but also with a non-terrestrial station device (such as the base station 20).

[0066] Figure 2FIG. is a diagram showing an example of a wireless network provided by a communication system 1. Base stations 20 and 30 each constitute a cell. A cell is an area for wireless communication covered by a base station. The cells constituted by base stations 20 and 30 can be any of macro cells, micro cells, femto cells, and small cells. The communication system 1 can be configured such that a single base station manages multiple cells or multiple base stations manage one cell. The cell provided by a base station is called a serving cell. The serving cell includes a primary cell (PCell) and a secondary cell (SCell). In the case where dual connectivity (e.g., EUTRA-EUTRA dual connectivity, EUTRA-NR dual connectivity (ENDC), EUTRA-NR dual connectivity with 5GC, NR-EUTRA dual connectivity (NEDC), NR-NR dual connectivity) is provided to a UE (e.g., terminal device 50), the PCell provided by the master node (MN) and zero or one or more SCell are called the primary cell group. In addition, the serving cell may include a primary secondary cell or a primary SCG cell (PSCell). In other words, in the case where dual connectivity is provided to the UE, the PSCell provided by the secondary node (SN) and zero or one or more SCell are called the secondary cell group (SCG). Unless specifically configured (e.g., PUCCH on the SCell), the physical uplink control channel (PUCCH) is transmitted by the PCell and the PSCell, rather than by the SCell. Radio link failure is also detected in the PCell and the PSCell, rather than in the SCell (it does not have to be detected in the SCell). The PCell and the PSCell thus have a special role in the serving cell, and therefore, they are also called special cells (SpCell). One downlink component carrier and one uplink component carrier can be associated with one cell. In addition, the system bandwidth corresponding to one cell can be divided into multiple bandwidth parts. In this case, one or more bandwidth parts can be set for the UE, and one bandwidth part can be used by the UE as the active BWP. In addition, for each cell, each component carrier, or each BWP, the radio resources (e.g., frequency band, numerology (subcarrier spacing), time slot structure) that can be used by the terminal device 50 can be different.

[0067] In Figure 2 the example of, base stations 301 and 302 constitute a terrestrial network TN1, and base stations 303, 304, and 305 constitute a terrestrial network TN2. In one example, the terrestrial network TN1 and the terrestrial network TN2 are terrestrial networks operated by a mobile network operator (MNO) (such as a telephone company). The terrestrial network TN1 and the terrestrial network TN2 can be operated by different mobile network operators (i.e., MNOs with different PLMNs), or can be operated by the same mobile network operator. The terrestrial network TN1 and the terrestrial network TN2 can also be regarded as one terrestrial network.

[0068] The terrestrial network TN1 and the terrestrial network TN2 are individually connected to the core network. In Figure 2 the example, the base station 30 configuring the terrestrial network TN2 is connected to the core network CN composed of the management device 101 and the like. When the radio access scheme of the terrestrial network TN2 is LTE, the core network CN is an EPC. Additionally, when the radio access scheme of the terrestrial network TN2 is NR, the core network CN is a 5GC. Understandably, the core network CN is not limited to the EPC or the 5GC, and it can be a core network using other radio access schemes. Furthermore, the terrestrial network TN1 is not connected to the core network in Figure 2 the example, but the terrestrial network TN1 can be connected to the core network CN. Additionally, the terrestrial network TN1 can be connected to a core network different from the core network CN (not shown).

[0069] The core network CN has a gateway device, an inter-gateway switch, etc., and is connected to the public network PN via the gateway device. In one example, the public network PN is a public data network such as the Internet, a regional IP network, and telephone networks (such as mobile telephone networks and fixed-line telephone networks). In one example, the gateway device is a server device connected to the Internet, a regional IP network, etc. In one example, the inter-gateway switch is a telephone switch connected to the telephone network of a telephone company. The management device 101 can have the function of a gateway device or an inter-gateway switch.

[0070] Figure 2 The base stations 20 and 40 shown in are both non-terrestrial station devices such as satellite stations and aircraft stations. A group of satellite stations (or a single satellite station) constituting the non-terrestrial network is called a spaceborne platform. Additionally, a group of aircraft stations (or a single aircraft station) constituting the non-terrestrial network is called an airborne platform. In Figure 2 the example, the base stations 202, 401, and 402 constitute the spaceborne platform SBP1. The base station 201 constitutes the spaceborne platform SBP2. Additionally, the base station 203 constitutes the airborne platform ABP1.

[0071] The terminal device 50 can communicate with both the base station 30 and the base station 20. In Figure 2 the example, the terminal device 501 can communicate with the base station 30 constituting the terrestrial network TN1. Additionally, the terminal device 501 can communicate with the base stations 20 constituting the spaceborne platforms SBP1 and SBP2. Additionally, the terminal device 501 can also communicate with the base station 20 constituting the airborne platform ABP1. Furthermore, the terminal device 501 may be able to directly communicate with other terminal devices 50 ( Figure 2 the terminal device 502 in the example).

[0072] Base station 20 is connected to the terrestrial network or the core network via relay station 60. The base stations 20 that make up the spaceborne platforms SBP1 and SBP2 are connected to the terrestrial network TN1 via relay station 601. Additionally, the base stations 20 that make up the spaceborne platforms SBP1, SBP2, and the airborne platform ABP1 are connected to the core network CN via relay station 602. Furthermore, the base stations 20 can also communicate directly with each other among the base stations 20 without going through the relay station 60.

[0073] In one example, the relay station 60 is an aircraft station or an earth station. An aircraft station is a radio station installed on the ground or on a moving body that moves on the ground to communicate with the aircraft station. Additionally, an earth station is a radio station located on the earth (including in the air) to communicate with a satellite station (space station). The earth station can be a large earth station or a small earth station, such as a very small aperture terminal (VSAT). Furthermore, the earth station can be a VSAT control 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). Additionally, the earth station can be a radio station installed in a moving body that moves on the ground. In one example, an example of an earth station installed on a ship includes an earth station on ship (ESV). Additionally, the earth station can include an aircraft earth station, which is installed in an aircraft (including a helicopter) and communicates with the satellite station. Additionally, the earth station can include an aeronautical earth station, which is installed in a moving body that moves on the ground and communicates with the aircraft earth station via the satellite station. Furthermore, the relay station 60 can be a portable mobile station that communicates with a satellite station or an aircraft station. The relay station 60 can be regarded as part of the communication system 1.

[0074] Each device that makes up the spaceborne platforms SBP1 and SBP2 performs satellite communication with the terminal device 50. Satellite communication represents wireless communication between the satellite station and the terminal device 50. Figure 3 is a diagram showing an overview of the satellite communication provided by the communication system 1. The satellite stations are mainly divided into geostationary orbit satellite stations and low earth orbit satellite stations.

[0075] The geostationary orbit satellite station is located at a height of approximately 35,786 km and rotates around the earth at the same speed as the rotation of the earth. In Figure 3 the example, the base station 201 that makes up the spaceborne platform SBP2 is a geostationary orbit satellite station. The geostationary orbit satellite station has a relative speed of approximately zero with the terminal device 50 and appears stationary when observed from the terminal device 50 on the ground. The base station 201 performs satellite communication with the terminal devices 501, 503, 504, etc. located on the earth.

[0076] A low Earth orbit satellite station is a satellite station that orbits at a lower altitude compared to a geostationary orbit satellite station and a medium Earth orbit satellite station. In one example, a low Earth orbit satellite station is a satellite station located between an altitude of 500 km and 2000 km. In Figure 3 the example, base stations 202 and 203 that make up the spaceborne platform SBP1 are low Earth orbit satellite stations. Additionally, Figure 3 only shows two base stations 202 and 203 as satellite stations that make up the spaceborne platform SBP1. However, the satellite stations that make up the spaceborne platform SBP1 have two or more (e.g., dozens to thousands) base stations 20, and the two or more base stations 20 actually form a low Earth orbit satellite constellation. Different from a geostationary orbit satellite station, a low Earth orbit satellite station has a relative velocity with respect to a terminal device 50 on the ground and appears to be moving when observed from the terminal device 50 on the ground. Base stations 202 and 203 individually form cells and perform satellite communication with terminal devices 501, 502, 503, etc. located on the Earth.

[0077] Figure 4 is a diagram showing an example of a cell formed by satellite stations. Figure 4 shows a cell C2 formed by base station 203, and base station 203 is a low Earth orbit satellite station. A satellite station orbiting in a low Earth orbit communicates with a terminal device 50 on the ground in a predetermined directionality. In one example, Figure 4 the angle R1 shown in Figure 4 is 40 degrees. In Figure 4 the case, in one example, the radius D1 of the cell C2 formed by base station 203 is 1000 km. A low Earth orbit satellite station moves at a constant speed. In the case where a low Earth orbit satellite station has difficulty providing satellite communication to a terminal device 50, a subsequent low Earth orbit satellite station provides satellite communication. In Figure 4 the example case, in the case where base station 203 has difficulty providing satellite communication to terminal device 50, subsequent base station 204 provides satellite communication. Additionally, the values of the above angle R1 and radius D1 are only examples and are not limited thereto.

[0078] As described above, the terminal device 50 can perform wireless communication using a non-terrestrial network. In addition, the base stations 20 and 40 in the communication system 1 constitute a non-terrestrial network. This enables the communication system 1 to extend services even to the terminal device 50 located in an area not covered by the terrestrial network. In one example, the communication system 1 can provide public safety and critical communication for the terminal device 50 (such as, Internet of Things (IoT) devices and machine type communication (MTC) devices). In addition, the use of the non-terrestrial network improves service reliability and resilience, so the communication system 1 can reduce the vulnerability of services to physical attacks or natural disasters. In addition, the communication system 1 can achieve service connection with aircraft terminal equipment (such as passengers on an airplane and drones) and service connection with mobile body terminal equipment (such as ships and trains). In addition, the communication system 1 can implement A / V content services, group communication, IoT-based broadcast services, software download services, high-performance multicast services (such as emergency messages), high-performance broadcast services, etc. In addition, the communication system 1 can support traffic offload between the terrestrial network and the non-terrestrial network. For the above implementation, the non-terrestrial network provided by the communication system 1 preferably operates integratively with the terrestrial network provided by the communication system 1 at the upper layer, but is not limited thereto. In addition, the non-terrestrial network provided by the communication system 1 preferably has a common radio access scheme with the terrestrial network provided by the communication system 1, but is not limited thereto.

[0079] Next, the structure of each device constituting the communication system 1 according to the present embodiment will be described in detail now.

[0080] <2-2. Structure of the management device>

[0081] The management device 10 is a device for managing a wireless network. For example, the management device 10 is a device for managing communication between the base stations 20 and 30. If the core network is EPC, in one example, the management device 10 is a device having the function of a mobility management entity (MME). In addition, if the core network is 5GC, in one example, the management device 10 is a device having the function of an access and mobility management function (AMF). In addition, the management device 10 can have the function of a gateway. In one example, if the core network is EPC, the management device 10 can be used as a serving gateway (S-GW) or a packet data network gateway (P-GW). In addition, if the core network is 5GC, the management device 10 can have the function of a user plane function (UPF). In addition, the management device 10 is not necessarily a device constituting the core network. In one example, if the core network is a core network based on W-CDMA or cdma2000, the management device 10 can be a device used as a radio network controller (RNC).

[0082] Figure 5 This is a diagram showing a structural example of the management device 10 according to an embodiment of the present disclosure. The management device 10 includes a communication unit 11, a storage unit 12, and a control unit 13. In addition, Figure 5 the structure shown in

[0083] is a functional structure, and its hardware structure may be different from the shown structure. Additionally, the functions of the management device 10 may be implemented in a form distributed among a plurality of physically separated components. In one example, the management device 10 may be composed of a plurality of server devices.

[0084] 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. In one example, the communication unit 11 may be a local area network (LAN) interface (such as a network interface card (NIC)), or may be a universal serial bus (USB) interface (including a USB host controller, a USB port, etc.). Additionally, the communication unit 11 may be a wired interface or a wireless interface. The communication unit 11 serves as a communication tool for the management device 10. The communication unit 11 communicates with the base station 30 or the relay station 60 under the control of the control unit 13.

[0085] The control unit 13 is a controller that controls each component of the management device 10. The control unit 13 is configured by including a processor (such as a central processing unit (CPU) and a microprocessing unit (MPU)). In one example, the control unit 13 executes its functions by the processor using a random access memory (RAM) or the like as a working area to execute various programs stored in the storage device inside the management device 10. Additionally, the control unit 13 may be configured as an integrated circuit such as an application specific integrated circuit (ASIC) and a field programmable gate array (FPGA). Each of the CPU, MPU, ASIC, and FPGA may be regarded as a controller.

[0086] <2-3. Structure of the Base Station>

[0087] Next, the structure of the base station will be described. The communication system 1 includes base stations 20, 30, and 40 as base stations. All of the base stations 20 to 40 may be movable. The structure of the base station 20 will be described below as the structure of the base station. The structures of the base stations 30 and 40 may be the same as the structure of the base station 20 to be described below.

[0088] Figure 6 is a diagram showing an example of the structure of the base station 20 according to an embodiment of the present disclosure. The base station 20 includes a wireless communication unit 21, a storage unit 22, and a control unit 23. In addition, Figure 6 the structure shown in is a functional structure, and its hardware structure may be different from the shown structure. Additionally, the functions of the base station 20 may be distributed among and implemented by a plurality of physically separated components.

[0089] The wireless communication unit 21 is a wireless communication interface that communicates with other wireless terminal devices (e.g., the terminal device 50 or the relay station 60) in a wireless manner. The wireless communication unit 21 supports one or more radio access schemes. In one example, the wireless communication unit 21 supports both NR and LTE. In addition to NR and LTE, the wireless communication unit 21 is also capable of supporting W-CDMA or cdma2000. The wireless communication unit 21 includes a receiving processor 211, a transmitting processor 212, and an antenna 213. The wireless communication unit 21 may include a plurality of receiving processors 211, transmitting processors 212, and antennas 213. Further, in the case where the wireless communication unit 21 supports multiple radio access schemes, each component of the wireless communication unit 21 may be configured to individually support each radio access scheme. In one example, the receiving processor 211 and the transmitting processor 212 may be configured to individually support LTE and NR.

[0090] The receiving processor 211 processes the uplink signal received via the antenna 213. The receiving processor 211 includes a wireless receiver 211a, a demultiplexer 211b, a demodulator 211c, and a decoder 211d.

[0091] The wireless receiver 211a down-converts the uplink signal, removes unnecessary frequency components, controls the amplification level, performs quadrature demodulation, performs conversion to a digital signal, removes the guard interval, extracts the frequency-domain signal using the fast Fourier transform, and so on. The demultiplexer 211b separates the signal output from the wireless receiver 211a into an uplink channel (such as a physical uplink shared channel (PUSCH) or a physical uplink control channel (PUCCH)) and an uplink reference signal. The demodulator 211c demodulates the received signal using a modulation scheme (such as binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK)) for the modulation symbols of the uplink channel. The modulation scheme used by the demodulator 211c may be 16 quadrature amplitude modulation (QAM), 64QAM, or 256QAM. The decoder 211d performs a decoding process on the encoded bits of the demodulated uplink channel. The decoded uplink data and uplink control information are output to the control unit 23.

[0092] The transmission processor 212 performs the transmission process of the downlink control information and the downlink data. The transmission processor 212 includes an encoder 212a, a modulator 212b, a multiplexer 212c, and a wireless transmitter 212d.

[0093] The encoder 212a encodes the downlink control information and the downlink data input from the control unit 23 using an encoding scheme (such as block coding, convolutional coding, and turbo coding). The modulator 212b modulates the encoded bits output from the encoder 212a using a predetermined modulation scheme (such as BPSK, QPSK, 16QAM, 64QAM, and 256QAM). The multiplexer 212c multiplexes the modulation symbols of each channel and the downlink reference signal, and arranges the result in a predetermined resource element. The wireless transmitter 212d performs various types of signal processing on the signal from the multiplexer 212c. In one example, the wireless transmitter 212d performs processing such as conversion to the time domain implemented by the fast Fourier transform, addition of the guard interval, generation of a baseband digital signal, conversion to an analog signal, quadrature modulation, up-conversion, removal of additional frequency components, and power amplification. The signal generated by the transmission processor 212 is transmitted through the antenna 213.

[0094] The storage unit 22 is a data readable / writable storage device such as a DRAM, SRAM, flash memory, and hard disk. The storage unit 22 serves as a storage tool for the base station 20. The storage unit 22 stores handover information. The handover information is information used by the terminal device 50 to switch the base station. In one example, the handover information includes information such as resource information, trigger information, timing advance information, and so on.

[0095] The resource information is information related to radio resources used by the connected terminal device 50 to perform wireless communication with a base station configured to be movable as a candidate handover destination. Further, the trigger information is information used by the terminal device 50 to determine whether to hand over the base station as the connection destination. Further, the timing advance information is information related to the timing advance for the terminal device 50 to connect to a base station as a candidate handover destination. The resource information, the trigger information, and the timing advance information will be described in detail later.

[0096] The control unit 23 is a controller that controls each component of the base station 20. The control unit 23 is configured by including processors such as a central processing unit (CPU) and a microprocessing unit (MPU). In one example, the control unit 23 executes its functions by the processor using a random access memory (RAM) or the like as a working area to execute various programs stored in a storage device inside the base station 20. Further, the control unit 23 may be configured as an integrated circuit such as an application specific integrated circuit (ASIC) and a field programmable gate array (FPGA). Each of the CPU, MPU, ASIC, and FPGA can be regarded as a controller.

[0097] <2-4. Structure of the terminal device>

[0098] Next, the structure of the terminal device 50 will be described. Figure 7 is a diagram showing a structural example of the terminal device 50 according to an embodiment of the present disclosure. The terminal device 50 includes a wireless communication unit 51, a storage unit 52, a network communication unit 53, an input / output unit 54, and a control unit 55. Further, Figure 7 the structure shown in is a functional structure, and its hardware structure may be different from the shown structure. Further, the functions of the terminal device 50 may be distributed in a plurality of physically separated components and implemented. Further, Figure 7 the structure shown in is an example, and not all of the wireless communication unit 51, the storage unit 52, the network communication unit 53, the input / output unit 54, and the control unit 55 are necessary 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 do not necessarily have to be necessary components.

[0099] The wireless communication unit 51 is a wireless communication interface that communicates with other wireless communication devices (e.g., base stations 20, 30, and 40) in a wireless manner. The wireless communication unit 51 supports one or more radio access schemes. In one example, the wireless communication unit 51 supports both NR and LTE. In addition to NR and LTE, the wireless communication unit 51 is also capable of supporting W-CDMA or cdma2000. The wireless communication unit 51 includes a receive processor 511, a transmit processor 512, and an antenna 513. The wireless communication unit 51 can include multiple receive processors 511, transmit processors 512, and antennas 513. Further, in the case where the wireless communication unit 51 supports multiple radio access schemes, each component of the wireless communication unit 51 can be configured to individually support each radio access scheme. In one example, the receive processor 511 and the transmit processor 512 can be configured to individually support LTE and NR.

[0100] The receive processor 511 processes the downlink signals received via the antenna 513. The receive processor 511 includes a wireless receiver 511a, a demultiplexer 511b, a demodulator 511c, and a decoder 511d.

[0101] The wireless receiver 511a down-converts the downlink signals, removes unnecessary frequency components, controls the amplification level, performs quadrature demodulation, performs conversion to a digital signal, removes the guard interval, extracts the frequency-domain signals using fast Fourier transform, and so on. The demultiplexer 511b separates the signals output from the wireless receiver 511a into a downlink channel, a downlink synchronization signal, and a downlink reference signal. The downlink channel is a channel such as a physical broadcast channel (PBCH), a physical downlink shared channel (PDSCH), and a physical downlink control channel (PDCCH). The demodulator 211c demodulates the received signals of the modulated signals of the downlink channel using modulation schemes such as BPSK, QPSK, 16QAM, 64QAM, and 256QAM. The decoder 511d performs decoding processing on the encoded bits of the demodulated downlink channel. The decoded downlink data and downlink control information are output to the control unit 23.

[0102] The transmit processor 512 performs the transmission processing of the uplink control information and the uplink data. The transmit processor 512 includes an encoder 512a, a modulator 512b, a multiplexer 512c, and a wireless transmitter 512d.

[0103] The encoder 512a encodes the uplink control information and uplink data input from the control unit 55 using an encoding scheme such as block coding, convolutional coding, and turbo coding. The modulator 512b modulates the encoded bits output from the encoder 512a using a predetermined modulation scheme such as BPSK, QPSK, 16QAM, 64QAM, and 256QAM. The multiplexer 512c multiplexes the modulated symbols of each channel and the uplink reference signal, and arranges the result in a predetermined resource element. The wireless transmitter 512d performs various types of signal processing on the signal from the multiplexer 512c. In one example, the wireless transmitter 512d performs processing such as conversion to the time domain implemented by inverse fast Fourier transform, addition of a guard interval, generation of a baseband digital signal, conversion to an analog signal, quadrature modulation, upconversion, removal of additional frequency components, and power amplification. The signal generated by the transmission processor 512 is transmitted through the antenna 513.

[0104] The storage unit 52 is a data-readable / writable storage device such as DRAM, SRAM, flash memory, and a hard disk. The storage unit 52 serves as a storage tool for the terminal device 50. The storage unit 52 stores handover information. The handover information is information obtained from the base stations 20, 30, or 40 and is used by the terminal device 50 for handover of the base station. In one example, the handover information includes 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.

[0105] The network communication unit 53 is a communication interface for communicating with other devices. In one 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 serves as a network communication tool for the terminal device 50. The network communication unit 53 communicates with other devices under the control of the control unit 55.

[0106] The input / output unit 54 is a user interface for exchanging information with the user. In one example, the input / output unit 54 is an operating device for the user to perform various operations such as a keyboard, a mouse, operation keys, and a touch panel. Additionally, the input / output unit 54 is a display device such as a liquid crystal display (LCD) and an organic light-emitting diode (EL) display. The input / output unit 54 can be an acoustic device such as a speaker and a buzzer. Additionally, the input / output unit 54 can be an illumination device such as a light-emitting diode (LED) lamp. The input / output unit 54 serves as an input / output tool (input tool, output tool, operating tool, or notification tool) for the terminal device 50.

[0107] The control unit 55 is a controller that controls each component of the terminal device 50. The control unit 55 is configured by including processors such as a central processing unit (CPU) and a microprocessing unit (MPU). In one example, the control unit 55 executes its functions by the processor using a random access memory (RAM) or the like as a working area and executing various programs stored in the storage device inside the terminal device 50. Further, the control unit 55 may be configured as an integrated circuit such as an ASIC and an FPGA. Each of the CPU, MPU, ASIC, and FPGA can be regarded as a controller.

[0108] <2-5. Initial connection processing>

[0109] Next, the operation of the communication system 1 will be described. First, the initial connection processing will be described. The initial connection (initial access) is a process for transitioning from the idle state (RRC_IDLE) where the UE (terminal device 50) is not connected to any RAN (base stations 20 and 30) to the connected state (RRC_CONNECTED) where the UE is connected to one of the RANs.

[0110] Figure 8 is a flowchart showing an example of the initial connection processing. The initial connection processing will be described below with reference to Figure 8 Describe the initial connection processing. For example, when the UE (terminal device 50) is started, the initial connection processing described below is executed.

[0111] First, the terminal device 50 in the idle state performs cell search. Cell search is a process for the UE to detect the physical cell ID (PCI) of a cell and obtain time and frequency synchronization. The cell search in this embodiment includes steps of detecting synchronization signals and decoding the PBCH. The synchronization signal (SS) in NR includes a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). In NR, the PSS, SSS, and PBCH are transmitted as a set. This set is called an SS / PBCH block (SSB). Additionally, multiple SSBs are transmitted per unit time (e.g., a half-frame (5 ms)). The multiple SSBs transmitted per half-frame are called an SSB burst, an SS burst, an SSB burst set, or an SS burst set. The SSB burst is transmitted periodically and repeatedly according to the periodicity 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, for example, a beam. Furthermore, the number of 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 beam with the highest quality in the SSB burst. The control unit 55 achieves synchronization with the cell in the downlink based on the detected synchronization signals. Then, after synchronization in the downlink is achieved, the control unit 55 attempts to decode the PBCH and obtain the master information block (MIB) which is part of the system information (step S102).

[0112] System information is information for notifying the configuration in the cell that transmits the system information. In one example, the system information includes information related to access to the cell (e.g., random access) (e.g., RACH-Config), information related to cell selection, information related to other RATs or other systems, etc. The system information includes the MIB and system information blocks (SIBs). The MIB is information at the physical layer required to receive SIBs, etc., and is information with a fixed payload size notified on the PBCH. The MIB includes the downlink system bandwidth, a part of the system frame number, SIB scheduling information, etc. The SIB is system information other than the MIB and is notified on the PDSCH.

[0113] Furthermore, the 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 access to the cell, information about the acquisition of other system information, and information about cell selection. In LTE, the information included in the MIB is the first system information. Additionally, the information included in SIB1 and SIB2 in the SIBs is the second system information. The remaining system information is the third system information.

[0114] In NR, system information is also notified from the NR cell. A physical channel carrying the system information can be transmitted in a time slot or a mini-slot. A mini-slot is defined by a number of symbols less than the number of symbols in a time slot. Transmitting the physical channel carrying the system information in a mini-slot enables the time spent on beam scanning to be reduced, thereby reducing the overhead. For NR, the first system information is transmitted on the NR-PBCH, and the second system information is transmitted on a physical channel different from the NR-PBCH.

[0115] The control unit 55 of the terminal device 50 acquires the second system information based on the MIB (that is, the first system information) (step S103). As described above, the second system information consists of SIB1 and SIB2. SIB1 is the cell access adjustment information and the scheduling information of the system information other than SIB1. In the case of NR, SIB1 includes information related to cell selection (for example, cellSelectionInfo), information related to cell access (for example, cellAccessRelatedInfo), information related to connection establishment failure control (for example, connEstFailureControl), the scheduling information of the system information other than SIB1 (for example, si-SchedulingInfo), the settings of the serving cell, etc. The settings of the serving cell include cell-specific parameters, downlink settings, uplink settings, TDD setting information, etc. The uplink settings include RACH settings, etc. In the case of LTE, SIB1 includes cell access information, cell selection information, maximum uplink transmission power information, TDD setting information, the period of the system information, the mapping information of the system information, and the length of the system information (SI) window length, etc. In addition, in the case of NR, SIB2 includes cell reselection information (for example, cellReselectionInfoCommon) and cell reselection serving frequency information (for example, cellReselectionServingFreqInfo). In the case of LTE, SIB2 includes connection prohibition information, cell common radio resource setting information (radioResourceConfigCommon), uplink carrier information, etc. The cell common radio resource setting information includes the setting information regarding the physical random access channel (PRACH) and the random access channel (RACH) that are common to the cell.

[0116] In addition, in the case where the control unit 55 cannot acquire the system information required for establishing a link, the control unit 55 of the terminal device 50 determines that access to the cell is prohibited. In one example, in the case where neither the first system information nor the second system information can be acquired, the control unit 55 determines that access to the cell is prohibited. In this case, the control unit 55 ends the initial connection process.

[0117] When the system information can be obtained, the control unit 55 performs a random access procedure (step S104) based on the first system information and / or the second system information. The random access procedure is sometimes referred to as a random access channel procedure (RACH procedure) or an RA procedure. In the RACH procedure, the UE first sends a random access preamble, and then monitors the random access response identified by the RA-RNTI for the PDCCH of the cell during the time period indicated by the configured IE ra-response window. On the other hand, when the transmitted preamble reaches the RAN without collision, a random access response including a preamble identifier corresponding to the PREAMBLE_INDEX that is the index of the transmitted preamble is sent from the RAN to the UE. When the UE receives a random access response including a preamble identifier corresponding to the transmitted PREAMBLE_INDEX while the ra-response window is running, the UE recognizes that the random access procedure has been successfully completed. Then, when the UE sends an RRCSetupRequest message in 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 RRCConnected), and identifies the current cell (the cell in which the RACH procedure and the RRC setup procedure have been performed) as the primary cell.

[0118] <2-6. Examples of HARQ processes>

[0119] Here, in the communication processing (e.g., the above-described initial connection processing) performed by the control unit 55 of the terminal device 50 and the control unit (e.g., control unit 23) of the base station device (e.g., base station 20, base station 30), hybrid ARQ (HARQ) is used for error correction in data. For example, HARQ is used for PDSCH data transmission, PUSCH data transmission, and PSSCH data transmission.

[0120] HARQ is a tool for obtaining coding gain by performing error correction through soft combining of the data initially transmitted and the retransmitted data. To perform HARQ, the base station device or the terminal device 50 stores the data that fails to be decoded in the HARQ buffer, combines the retransmitted data and the stored data, and performs error correction. More specifically, one HARQ process may include the following operations. The MAC entity in the UE (terminal device 50) determines whether the received data is newly transmitted data or retransmitted data from the new data indicator (NDI) in the DCI that schedules the transmission resource of the data. In the case where the received data is newly transmitted data, the MAC entity attempts to decode the received data. In the case where the received data is retransmitted data and the data in the transport block has not been successfully decoded yet, the MAC entity instructs the physical layer to combine the data currently present in the soft buffer for the transport block with the received data, and attempts to decode the combined data. In the case where the data attempted to be decoded by the MAC entity is successfully decoded, or in the case where the data has been successfully decoded previously, the decoded MAC PDU is transmitted to the upper layer or the disassembling and demultiplexing entity. In the case where the data attempted to be decoded by the MAC entity is not successfully decoded, and in the case where the data has not been successfully decoded previously, the MAC entity instructs the physical layer to replace the data in the soft buffer for the transport block with the data attempted to be decoded. Then, the MAC entity instructs the physical layer to generate an acknowledgement of the data in the transport block, that is, HARQ feedback (ACK / NACK).

[0121] For each HARQ process to which identification information (e.g., HARQ process identifier) is assigned, HARQ processing is performed. In other words, in the case where there are multiple HARQ processes, HARQ processing can be performed in parallel. The base station device or the terminal device 50 is capable of maintaining one or more HARQ processes. More specifically, the MAC entity includes HARQ entities for each serving cell. The HARQ entities maintain a large number of parallel HARQ processes. HARQ processing can be applied not only to the downlink but also to the uplink. In this case, the MAC entity includes HARQ entities for each serving cell configured with the uplink. As described above, each HARQ process is associated with a HARQ process identifier. The number of HARQ processes for the downlink may be different from the number of HARQ processes for the uplink, or the same as the number of HARQ processes for the uplink. The HARQ entity transmits, for example, HARQ information and the associated TB to the corresponding HARQ process.

[0122] The base station apparatus in the following description can be implemented regardless of whether the base station apparatus is a base station 20 (such as a satellite station, a drone, a balloon, or an aircraft) or a base station 30 that serves as a communication apparatus. The base station 30 is a terminal apparatus. Additionally, although specific values will be provided in the description to indicate specific examples in the following description, the values are not limited to the examples, and other values can be used.

[0123] In addition, in the following description, resources represent frequency, time, resource elements (including REG, CCE, CORESET), resource blocks, bandwidth parts, component carriers, symbols, sub - symbols, time slots, mini - slots, sub - slots, sub - frames, frames, PRACH opportunities, opportunities, codes, multiple access physical resources, multiple access signatures, sub - carrier spacing (in number theory), etc. Additionally, the HARQ process identifier in the following description can be understood as the HARQ process number.

[0124] <2 - 7. Overview of the Embodiment>

[0125] Here, Figure 9 a situation will be described where a handover occurs during data transmission from a terminal apparatus to a base station apparatus. Figure 9 is a sequence diagram showing the processing of the terminal apparatus 50 and the base station apparatus before and after the handover that occurs during data transmission.

[0126] As Figure 9 shown, first, the base station apparatus 1 establishes a downlink synchronization with the terminal apparatus, and then sends the cell ID of the cell of the base station apparatus 1 to the terminal apparatus (step S201).

[0127] Next, a random access procedure is performed between the base station apparatus 1 and the terminal apparatus (step S202).

[0128] Next, it is assumed that the terminal apparatus generates transmission data A (step S203). In this case, the terminal apparatus sends a scheduling request to the base station apparatus 1 (step S204).

[0129] The base station apparatus 1 then sends an uplink grant to the terminal apparatus (step S205).

[0130] Next, the terminal apparatus repeatedly sends the same data A to the base station apparatus 1 based on the received uplink grant (step S206). Here, the maximum number of transmissions in the repeated transmission performed by the terminal apparatus is predetermined as M times, and when the first to the Nth transmissions among the M times are completed in step S206, N pieces of data are synthesized at the base station apparatus 1. Here, M ≥ 1.

[0131] Next, assume that: the base station device 1 determines that a handover to the base station device 2 is required (step S207). Additionally, assume that: the base station device 1 fails to receive data A (step S208).

[0132] The base station device 1 then sends a handover request to the base station device 2 (step S209).

[0133] Then, the base station device 2 sends an ACK for the handover request to the base station device 1 (step S210).

[0134] Then, the base station device 1 sends an instruction to the terminal device to hand over to the base station device 2 (step S211). As a result, the terminal device switches the connection destination from the base station device 1 to the base station device 2 according to the handover instruction.

[0135] Next, the base station device 2 establishes a downlink synchronization with the terminal device, and then sends the cell ID of the cell of the base station device 2 to the terminal device (step S212).

[0136] Next, a random access procedure is performed between the base station device 2 and the terminal device (step S213).

[0137] The terminal device then sends a scheduling request to the base station device 2 (step S214).

[0138] The base station device 2 then sends an uplink grant to the terminal device (step S215).

[0139] Next, the terminal device repeatedly sends the same data A to the base station device 2 based on the received uplink grant (step S216). Here, the maximum number of transmissions in the repeated transmissions performed by the terminal device is predetermined as M times.

[0140] For example, when observed from a terminal device on the ground, non-terrestrial stations (such as medium Earth orbit satellites, low Earth orbit satellites, and HAPS) appear to move at high speed above the ground, and thus the cells to be formed by non-terrestrial stations on the ground also move at high speed. In such a case, as described above, cell handover (handover) may occur during data transmission / reception, and thus data transmission / reception may fail. Additionally, considering that ground terminals (such as IoT terminals) in particular need to repeatedly send the same data hundreds to thousands of times because the propagation distance between non-terrestrial stations and ground terminals is long, and thus there is a high possibility that handover will occur during the transmission of the same data, which may lead to a high possibility of failure of data transmission / reception.

[0141] Therefore, in the present embodiment, the number of repetitions of data transmission / reception is reduced so that handover may not occur during data transmission.

[0142] Specifically, the terminal device 50 according to the embodiment transmits or receives data in cooperation with a plurality of terminal devices 50. Figure 10 And Figure 11 is a diagram showing a case where a plurality of terminal devices 50 cooperate to transmit data. Figure 12 is a diagram showing a case where a plurality of terminal devices 50 cooperate to receive data. It should be noted that although Figures 10 to 12 shows a case where four terminal devices 50 cooperate with each other, the number of terminal devices 50 that cooperate with each other can be 3 or less or 5 or more. It should be noted that although the description will be provided using the base station device as an example of the base station 20 in Figures 10 to 12 the base station device can be the base station 30.

[0143] As Figure 10 and Figure 11 shown in, the plurality of terminal devices 50 cooperate to transmit data to the base station 20. Then, the base station 20 receives the signals transmitted from each terminal device 50, synthesizes the signals, and then decodes the signals.

[0144] It should be noted that as Figure 10 shown in, the plurality of terminal devices 50 can encode data at each terminal device 50 and transmit the data to the base station 20, or as Figure 11 shown in, the plurality of terminal devices 50 can receive the data encoded at one of the terminal devices 50 and transmit the data to the base station 20.

[0145] In addition, as Figure 12 shown in, the plurality of terminal devices 50 cooperate to receive the data transmitted from the base station 20. Then, the plurality of terminal devices 50 aggregate the received data at one of the terminal devices 50 through inter-terminal communication or the like, synthesize the signals, and then decode the signals.

[0146] By the plurality of terminal devices 50 transmitting or receiving data in cooperation in this way, the number of repeated transmissions between the terminal device 50 and the base station 20 can be reduced, so that the failure of data transmission / reception due to the occurrence of handover can be reduced.

[0147] Although cooperative transmission will be described as an example below, cooperative transmission can be understood as cooperative reception.

[0148] <2-8. Determination Processing of Cooperative Terminals>

[0149] The cooperative transmission performed by the plurality of terminal devices 50 can include, for example, the following cases (1) or (2).

[0150] (1) Cooperative transmission is performed after a group is formed in advance.

[0151] (2) Perform cooperative transmission without pre-forming a group.

[0152] (1) Perform cooperative transmission after pre-forming a group.

[0153] When the plurality of terminal devices 50 cooperatively transmit data, a method can be adopted in which the terminal group that performs cooperative transmission is pre-determined. For example, the base station device quasi-statically notifies the terminal device 50 of which group the terminal device 50 belongs to. In other words, the terminal device 50 acquires information about a pre-determined group including other terminal devices 50, and repeatedly cooperatively transmits or receives data with the other terminal devices 50 included in the group. As quasi-static notification, for example, system information, RRC signaling, etc. can be used. For example, the base station device notifies the terminal ID (information such as C-RNTI) of the terminal device 50 belonging to the group. In addition, the base station device assigns a group ID to the group. Specifically, the base station device assigns the same group ID to the terminal devices 50 belonging to the same group. Multiple group IDs can be assigned to one terminal device 50. In other words, the terminal device 50 acquires identification information (group ID) for identifying the group or identification information (terminal ID) for identifying other terminal devices included in the group as information about the group.

[0154] (2) Perform cooperative transmission without pre-forming a group.

[0155] When the plurality of terminal devices 50 cooperatively transmit data, a method can be adopted in which the terminal group that performs cooperative transmission is dynamically determined. Alternatively, coordinated transmission is performed without the concept of a group.

[0156] For example, the base station device uses a dynamic notification tool (such as downlink control information (DCI)) to notify the terminal device 50 of the implementation of cooperative transmission. In addition, for example, terminal device A uses a dynamic notification tool (such as sidelink control information (SCI)) to notify terminal device B of the implementation of cooperative transmission. In other words, the terminal device 50 issues a dynamic notification to other terminal devices 50, and the dynamic notification instructs the terminal devices to repeatedly cooperatively transmit or receive data.

[0157] <2-9. Relationship between cooperative terminals>

[0158] When the plurality of terminal devices 50 perform cooperative transmission, it is necessary to determine which terminal device 50's data is to be transmitted. This situation can include the following situations (A) or (B). It should be noted that hereinafter, in the relationship between the master device and the slave device, the terminal device 50 that becomes the master device will be referred to as the "master device" or "master terminal", and the terminal device 50 that becomes the slave device will be referred to as the "slave device" or "slave terminal".

[0159] (A) Case where there is a relationship between the master device and the slave device

[0160] (B) Case where there is no relationship between the master device and the slave device

[0161] (A) Case where there is a relationship between the master device and the slave device

[0162] Consider the case where the slave terminal sends data of the master terminal. In this case, it is necessary to determine which terminal device 50 becomes the master device and which terminal device 50 becomes the slave device. For example, the base station device can notify the terminal device 50 which terminal device 50 is the master device and which terminal device 50 is the slave device. Specifically, the base station device sends a request to the terminal device 50 that becomes the master device and the terminal device 50 that becomes the slave device. In the case where the terminal device 50 that has received the request agrees to be the master device or the slave device, the terminal device 50 sends an ACK to the base station device, and in the case where the terminal device 50 does not agree to be the master device or the slave device, the terminal device 50 sends a NACK to the base station device.

[0163] It should be noted that it is not necessary to notify from the base station device which terminal device 50 becomes the master device or the slave device, and for example, it can be determined by the terminals using inter-terminal communication which terminal device 50 becomes the master device or the slave device. For example, in the case where the terminal device 50 collaboratively sends its own data, the terminal device 50 serves as the master device, and in the case where the terminal device 50 collaboratively sends data of other terminal devices 50, the terminal device 50 serves as the slave device. Specifically, the terminal device 50 that becomes the master device, that is, the terminal device 50 that stores the data to be sent to the base station device, sends a request to the terminal device 50 that becomes a candidate slave device by using inter-terminal communication. In the case where the terminal device 50 that has received the request agrees to become the slave device, the terminal device 50 sends an ACK to the terminal device 50 that becomes the master device, and in the case where the terminal device 50 does not agree to become the slave device, the terminal device 50 sends a NACK to the terminal device 50 that becomes the master device. In other words, in the case where the terminal device 50 serves as the master device, the terminal device 50 sends a notification requesting another terminal device 50 to serve as the slave device, and receives a notification regarding whether the other terminal device 50 agrees to serve as the slave device. In other words, the terminal device 50 receives a notification from another terminal device 50 that serves as the master device requesting the terminal device itself to serve as the slave device, and sends a notification indicating whether the terminal device itself agrees to serve as the slave device to the other terminal device 50.

[0164] After the relationship between the master device and the slave device is determined, the slave terminal needs to send the data of the master terminal. In other words, the master terminal needs to send information about the data to be sent to the slave terminal. In other words, when the terminal device 50 serves as the master device, the terminal device 50 sends predetermined data to another terminal device 50 serving as the slave device, and repeatedly sends such predetermined data.

[0165] For example, the master terminal sends a signal indicating encoded data to the slave terminal. Then, the slave terminal amplifies the power of the signal received from the master terminal or converts the frequency of the signal, and sends the signal to the base station device as it is. It should be noted that the slave terminal can send the signal to the base station device without amplifying the power.

[0166] In addition, the master terminal can send data to the slave terminal for each repeated transmission, or in order to reduce overhead, the master terminal can send data to the slave terminal only once at the start, and the slave terminal can repeatedly send the data received at the beginning. When the master terminal sends data to the slave terminal only once, the master terminal also sends information about the number of repeated transmissions. In other words, when the terminal device 50 sends predetermined data to another terminal device 50 serving as the slave device, the terminal device 50 also notifies information about the number of repeated transmissions.

[0167] It should be noted that in the case where there are multiple slave terminals, the master terminal can send different pieces of encoded data to each slave terminal. In other words, when the terminal device 50 serves as the master device, the terminal device 50 sends encoded data that has been subjected to different encoding processes to each of the multiple other terminal devices 50 serving as the slave device. For example, in the case where there are slave terminal A and slave terminal B, the master terminal sends a signal of data encoded with redundancy version = 2 to slave terminal A, and sends a signal of data encoded with redundancy version = 3 to slave terminal B. Then, slave terminals A and B send the signals received from the master terminal as they are after amplifying the power. In this way, as a result of sending signals of data encoded with different redundancy versions from different terminal devices 50 and the base station device synthesizing these received signals, a higher coding gain can be obtained compared to the coding gain in the case of sending signals with the same redundancy version.

[0168] The value of the redundancy version is not limited to the above examples. For example, in the case where there are four slave terminals, four redundancy versions = 0, 1, 2, 3 can be assigned to each slave terminal, or two redundancy versions = 0, 0, 3, 3 or three redundancy versions can be assigned.

[0169] In addition, when multiple slave terminals perform encoding using different values, the base station device needs to know which slave terminal encodes using which redundancy version. The ways to know the redundancy version can include the following examples.

[0170] - The base station device pre - assigns redundant versions.

[0171] - The master terminal selects a redundant version for each slave terminal and notifies the base station device of the selected redundant version using, for example, uplink control information (UCI). Note that, instead of UCI, the notification can be made by associating with the port number of the demodulation reference signal (DMRS).

[0172] In addition, in the presence of slave terminal A and slave terminal B, the master terminal can divide the transmitted data into three parts, allocate each divided part of the data to the master terminal, slave terminal A, and slave terminal B, and transmit the data. In other words, the terminal device 50 divides the predetermined data, allocates each divided part of the data to other terminal devices 50, and performs cooperative transmission. By dividing the transmitted data in this way and transmitting the transmitted data from multiple terminals, the coding rate of the data to be transmitted by one terminal can be reduced. In other words, a coding gain achieved by error correction can be obtained, and thus the number of re - transmissions can be reduced.

[0173] The data to be divided can be coded data. In this case, the physical size of the frequency and time resources required for transmission is reduced by the division, so that the resources can be used as resources for re - transmitting the divided data.

[0174] Note that this case is not limited to the case where the slave terminal transmits the coded data received from the master terminal as it is, and the slave terminal can decode the received coded data once, encode the data again, and transmit the data to the base station device. In this case, for example, as described below, the master terminal notifies the slave terminal of the information required for decoding and encoding processes.

[0175] - Transport block size (TBS) information

[0176] - MCS information

[0177] - Information about the number of layers

[0178] - Information about precoding

[0179] - Information about the terminal ID (C - RNTI, etc.)

[0180] - Information about redundant versions

[0181] - Information about the number of re - transmissions

[0182] - In addition to the above information, information required for coding specified in TS38.211 and TS38.212, etc.

[0183] Then, in the case where data transmission to the base station device is successful, the plurality of terminal devices 50 having a relationship between the master device and the slave device release the relationship between the master device and the slave device. For example, the determination of successful reception (successful transmission) can be performed by whether the master terminal receives an ACK indicating successful reception or a NACK indicating a reception failure from the base station device. ACK / NACK information may be notified from the master terminal to the slave terminal, or ACK / NACK information may be notified from the base station device to all terminal devices 50 in the master terminal and the slave terminal.

[0184] In addition, the ACK / NACK information may be notified from the base station to the terminal device 50 through control information notifying the ACK / NACK, or may be implicitly notified through notification (grant) of resources to be used for new data transmission.

[0185] In addition, when data transmission is successful, the relationship between the master device and the slave device can continue without being cancelled. For example, when a release request notification for releasing the relationship is issued from the master terminal to the slave terminal, the relationship between the master device and the slave device is cancelled, and when the release request notification is not issued, the relationship between the master device and the slave device continues.

[0186] A release request notification may be issued from the base station device to each of the master terminal and the slave terminal, a release request notification may be notified from the master terminal to the slave terminal, or a release request notification may be notified from the slave terminal to the master terminal. In other words, in the case where the terminal device 50 successfully cooperates to repeatedly send or receive predetermined data, and in the case where the terminal device 50 receives a release request notification from another device (base station device or another terminal device 50), the relationship between the master device and the slave device is canceled.

[0187] In addition, in the event that a situation occurs in which a slave terminal needs to send another data during data transmission, the slave terminal can suspend the transmission of the data of the master terminal being transmitted, and can preferentially transmit the other data. In other words, in the case where the terminal device 50 is used as a slave device, and in the case where a transmission request for another data is issued when the terminal device 50 cooperatively transmits the data of another terminal device 50 used as a master device, the terminal device 50 suspends the data transmission process and transmits the other data.

[0188] (B) When there is no relationship between the master device and the slave device

[0189] In the case where there is no relationship between the master device and the slave devices, that is, when the plurality of terminal devices 50 each have data to be transmitted, cooperative transmission can be performed. For example, the respective data of two terminal devices 50 can be combined into one piece of data, or instead of simply combining the data, each piece of data can be processed at the terminal device 50, the data center, etc., and the processed data can be used as the transmission data. In this case, the plurality of terminal devices 50 do not have to have a relationship between the master device and the slave devices, and the plurality of terminal devices 50 cooperatively transmit the same data shared through inter-terminal communication or the like.

[0190] <2-10. Transmission signal processing>

[0191] When the plurality of terminal devices 50 perform cooperative transmission, the plurality of terminal devices 50 need to perform transmission using transmission resources different between the terminals, such as orthogonal resources (such as time resources, frequency resources, or code resources) or non-orthogonal resources (such as non-orthogonal spreading codes, interleaver sequences, scrambling sequences, and power), etc.

[0192] In this case, for example, the base station device notifies the transmission resources allocated to each of the plurality of terminal devices 50. In other words, the terminal device 50 receives the transmission resources for transmitting the predetermined data from the base station device and performs cooperative transmission based on the transmission resources. Alternatively, the base station device can allocate the transmission resources to the master terminal, notify the master terminal of the allocated transmission resources, and the master terminal can divide the allocated transmission resources and allocate the transmission resources to each slave terminal. In other words, the terminal device 50 divides the transmission resources, allocates the divided resources to the other terminal devices 50, and performs cooperative transmission.

[0193] It should be noted that when the master terminal divides the transmission resources, the base station device that receives the data needs to be notified of information about the divided resources, etc. Alternatively, the base station device needs to know in advance how the master terminal divides the transmission resources. For example, when the base station device notifies the master terminal of the transmission resources, the base station device also notifies information about the division of the transmission resources (information about which resources are allocated to which slave terminal).

[0194] In addition, when the base station device issues a predetermined notification to all slave terminals, the base station device can notify using different control information for each slave terminal, or can commonly notify information about all slave terminals using one piece of control information.

[0195] In addition, when the sizes of the allocated transmission resources are different for each slave terminal, the TBS calculation results may be different between the master terminal and the slave terminals. For example, when the master terminal and the slave terminals transmit the same transport block (TB), if the TBSs are different, the TBs will be different, and thus the bit sequences after error correction coding will also be different. Therefore, in order to make the bit sequences after error correction coding the same, when performing cooperative transmission, the master terminal or the base station device notifies the slave terminal of an instruction to make the TBS the same as that of the master terminal. In other words, when the terminal device 50 serves as a slave device, the terminal device 50 makes the TBS consistent with the TBS of another terminal device 50 serving as a master device.

[0196] When the slave terminal device 50 transmits data, the terminal device 50 uses the identification ID (e.g., C-RNTI) allocated to the terminal device 50 to perform processes such as data scrambling and addition of cyclic redundancy check (CRC). Below, the processing of the identification ID in the case where the multiple terminal devices 50 perform cooperative transmission will be described. The processing of the identification ID to be described below can be applied to processes other than data scrambling and addition of CRC, that is, processing functions required for transmission signal processing or reception signal processing.

[0197] For example, in order to improve the reception power by repeated transmission, it is necessary to perform soft-combining on the received data. At this time, when the base station device as the receiving device misidentifies the identification ID used when generating the transmission data, there is a problem that soft-combining cannot be performed.

[0198] For example, when the terminal device A transmits data owned by the terminal device A, it is assumed that the terminal device A transmits a signal obtained by scrambling the data using the identification ID of the terminal device A. On the other hand, when the terminal device B transmits the data of the terminal device A, the terminal device B scrambles the data using one of the following three pieces of information. In other words, the terminal device 50 performs processing on the predetermined data, and the identification ID of the terminal device 50 as the owner of the predetermined data is associated with the processing.

[0199] - The identification ID of the terminal device A

[0200] - The identification ID of the terminal device B

[0201] - Information other than the identification ID

[0202] - The identification ID of the terminal device A

[0203] When the terminal device B scrambles data using the identification ID of the terminal device A, the terminal device B acquires in advance the identification ID of the terminal device A. In this case, when the terminal device B and the terminal device A perform cooperative transmission, the terminal device B scrambles the data using the identification ID of the terminal device A, and when the terminal device B transmits data alone (without performing cooperative transmission), the terminal device B scrambles the data using the identification ID of the terminal device B.

[0204] - Identification ID of the terminal device B

[0205] When the terminal device B scrambles data using the identification ID of the terminal device B, the terminal device B notifies in advance the base station device, which is the receiving device, of which resources or DMRS ports are used for transmitting the data of the terminal device A.

[0206] - Information other than the identification ID

[0207] For example, when the terminal device B scrambles data using the above group identification ID, the terminal device B notifies in advance all the terminal devices performing cooperative transmission of the information indicating the group identification ID. In this case, when the terminal devices in the group perform cooperative transmission, the data is scrambled using the group ID, and when the terminal device B performs transmission alone (without performing cooperative transmission), the data is scrambled using the identification ID of the terminal device B.

[0208] <2-11. Data>

[0209] Examples of the data to be cooperatively transmitted can include the following data.

[0210] - The transmission data of the master terminal is transmitted in cooperation with the slave terminal.

[0211] - The transmission data of the master terminal is divided into multiple pieces and transmitted in cooperation with the slave terminal.

[0212] - The data A acquired by the terminal device A and the data B acquired by the terminal device B are processed in a data center, for example, and the data C as the processing result is transmitted cooperatively by the terminal devices A and B.

[0213] - The transmission data of the master terminal is transmitted in cooperation with the slave terminal.

[0214] By the master terminal sending the data owned by the master terminal to the slave terminal, the master terminal and the slave terminal respectively send the same data (the data of the master terminal) to the base station device.

[0215] - The transmission data of the master terminal is divided into multiple pieces and transmitted in cooperation with the slave terminal.

[0216] For example, the master terminal divides the data to be transmitted into three pieces of data A, B, and C. The master terminal transmits data A, the slave terminal 1 transmits data B, and the slave terminal 2 transmits data C.

[0217] Next, a process of processing to be executed by the terminal device 50 according to the embodiment will be described with reference to Figure 13 FIG. Figure 13 is a flowchart showing a process of processing to be executed by the terminal device 50 according to the embodiment.

[0218] As Figure 13 shown, first, the terminal device 50 determines whether data to be transmitted to the base station device has been generated (step S301). If no data to be transmitted has been generated (step S301: No), the terminal device 50 repeatedly executes the process in step S301.

[0219] On the other hand, if data to be transmitted has been generated (step S301: Yes), the terminal device 50 transmits the generated data to another terminal device 50 that performs cooperative transmission (step S302). The data to be transmitted may be the same data or a part of the divided data.

[0220] Subsequently, the terminal device 50 repeatedly transmits data in cooperation with other terminal devices 50 (step S303).

[0221] Subsequently, the terminal device 50 determines whether the number of repetitions has been reached (step S304). If the number of repetitions has not been reached (step S304: No), the terminal device 50 repeats the process in step S304.

[0222] On the other hand, if the number of repetitions has been reached (step S304: Yes), the terminal device 50 ends the cooperative transmission with other terminal devices 50 (step S305) and ends the process.

[0223] <3. Modification Example>

[0224] The control device for controlling the management device 10, the base stations 20, 30, 40, or the terminal device 50 of the present embodiment can be configured as a dedicated computer system or a general-purpose computer system.

[0225] For example, a communication program for performing the above-mentioned operations (e.g., initial connection processing, HARQ processing, etc.) is stored in a computer-readable recording medium (such as an optical disk, a semiconductor memory, a magnetic tape, and a floppy disk) and distributed. Then, for example, a control device is constructed by installing the program on a computer and performing the above-mentioned processing. At this time, the control device may be an external device (e.g., a personal computer) of the management device 10, the base station 20, 30, 40, or the terminal device 50. In addition, the control device may be an internal device (e.g., a control unit 13, a control unit 23, or a control unit 55) of the base station 20, 30, 40, or the terminal device 50.

[0226] In addition, the above-mentioned communication program may be stored in a disk device in a server device arranged on a network (such as the Internet) in this manner so as to be downloaded to a computer. In addition, the above-mentioned functions may be realized by cooperation between an operating system (OS) and application software. In this case, the part other than the OS may be stored in a medium for distribution, or the part other than the OS may be stored in a server device and downloaded to a computer.

[0227] In addition, among the processes described in the above embodiments, all or part of the processes described as being automatically performed may be performed manually, or all or part of the processes described as being manually performed may be automatically performed by known methods. In addition, unless otherwise specified, the processing procedures, specific terms, and information including various data and parameters disclosed in the specification and the drawings may be optionally changed. In one example, the various types of information shown in each drawing are not limited to the information shown.

[0228] In addition, each component of each device shown in the drawings is conceptual in function and is not necessarily configured physically as shown in the drawings. In other words, the specific form of distribution or integration of each device is not limited to the example shown, and all or part of them may be functionally or physically distributed or integrated on an optional unit basis according to various loads and usage conditions.

[0229] In addition, appropriate combinations between the above-described embodiments are possible within the range in which the details of the processing are not contradictory. In addition, the order of the steps shown in the flowcharts or sequence diagrams of the above-described embodiments may be appropriately changed.

[0230] <4. Conclusion>

[0231] As described above, according to an embodiment of the present disclosure, the terminal device 50 includes a communication unit (wireless communication unit 51) and a control unit 55. The control unit 55 transmits or receives predetermined data a predetermined number of times via the wireless communication unit 51. In addition, the control unit 55 transmits or receives the predetermined data a predetermined number of times in cooperation with other terminal devices 50. This can reduce the number of times of duplicate data transmission or reception, and thus can reduce the failure of data transmission / reception due to the occurrence of handover.

[0232] Although the above describes the embodiments of the present disclosure, the technical scope of the present disclosure is not limited to the above embodiments themselves, and various modifications can be made without departing from the scope of the present disclosure. In addition, components in different embodiments and variations can be appropriately combined.

[0233] In addition, the effects in each embodiment described in this specification are only examples and do not limit the disclosure here, and other effects not described here can also be achieved.

[0234] Furthermore, the present technology can also have the structure described below.

[0235] (1) A terminal device, comprising:

[0236] A communication unit; and

[0237] A control unit,

[0238] configured to transmit or receive predetermined data a predetermined number of times via the communication unit,

[0239] wherein the control unit transmits or receives the predetermined data a predetermined number of times in cooperation with another terminal device.

[0240] (2) The terminal device according to (1), wherein the control unit

[0241] obtains information about a predetermined group including the other terminal device, and transmits or receives the predetermined data a predetermined number of times in cooperation with the other terminal device included in the group.

[0242] (3) The terminal device according to (2), wherein the control unit

[0243] obtains identification information for identifying the group or identification information for identifying the other terminal device included in the group as information about the group.

[0244] (4) The terminal device according to any one of (1) to (3) above, wherein the control unit

[0245] Send a dynamic notification to the other terminal device, the dynamic notification instructing the terminal device to cooperatively send or receive the predetermined data the predetermined number of times.

[0246] (5) The terminal device according to any one of (1) to (4) above, wherein the control unit

[0247] Acts as a master device when the terminal device cooperatively sends the data of the terminal device itself, and acts as a slave device when the terminal device cooperatively sends the data of the other terminal device.

[0248] (6) The terminal device according to (5) above, wherein the control unit

[0249] Sends a notification for requesting the other terminal device to act as a slave device when the terminal device acts as a master device, and receives a notification on whether the other terminal device agrees to act as a slave device.

[0250] (7) The terminal device according to any one of (5) to (6) above, wherein when the terminal device acts as a master device, the control unit sends the predetermined data to the other terminal device acting as a slave device and sends the predetermined data the predetermined number of times.

[0251] (8) The terminal device according to (7) above, wherein when the terminal device sends the predetermined data to the other terminal device acting as a slave device, the control unit also notifies the information on the predetermined number of times.

[0252] (9) The terminal device according to any one of (7) to (8) above, wherein when the terminal device acts as a master device, the control unit sends data that has undergone different encoding processes to each of a plurality of other terminal devices acting as slave devices.

[0253] (10) The terminal device according to any one of (7) to (9) above, wherein when the process of cooperatively sending or receiving the predetermined data the predetermined number of times is successful and a release request notification is received from another device, the control unit cancels the relationship between the master device and the slave device.

[0254] (11) The terminal device according to any one of (7) to (10) above, wherein the control unit

[0255] Receives a notification for requesting the terminal device itself to act as a slave device from the other terminal device acting as a master device, and sends a notification to the other terminal device on whether the terminal device itself agrees to act as a slave device.

[0256] (12) The terminal device according to any one of (7) to (11) above, wherein when the terminal device is used as a slave device and there is a request to send another data when the terminal device cooperatively sends the data of the other terminal device used as a master device, the control unit suspends the data sending process and sends the other data.

[0257] (13) The terminal device according to any one of (7) to (12) above, wherein when the terminal device is used as a slave device, the control unit makes the transport block size (TBS) consistent with the TBS of the other terminal device used as a master device.

[0258] (14) The terminal device according to any one of (1) to (13) above, wherein the control unit divides the predetermined data, allocates the divided data to the other terminal device, and performs cooperative transmission.

[0259] (15) The terminal device according to any one of (1) to (14) above, wherein the control unit receives transmission resources for sending the predetermined data from the base station device, and performs cooperative transmission based on the transmission resources.

[0260] (16) The terminal device according to any one of (1) to (15) above, wherein the control unit divides the transmission resources, allocates the divided resources to the other terminal device, and performs cooperative transmission.

[0261] (17) The terminal device according to any one of (1) to (16) above, wherein the control unit performs processing on the predetermined data, and the processing is associated with the identification ID of the terminal device that is the owner of the predetermined data.

[0262] (18) A base station device, comprising:

[0263] A communication unit; and

[0264] A control unit configured to receive predetermined data cooperatively sent from a plurality of terminal devices via the communication unit and combine the received predetermined data.

[0265] (19) A control method performed by a terminal device, the control method comprising:

[0266] Sending or receiving predetermined data a predetermined number of times via a communication unit; and

[0267] Sending or receiving the predetermined data a predetermined number of times in cooperation with another terminal device.

[0268] (20) A control method performed by a base station device, the control method comprising:

[0269] Receive predetermined data transmitted collaboratively from multiple terminal devices via a communication unit and combine the received predetermined data.

[0270] Label list

[0271] 1 Communication system

[0272] 10 Management device

[0273] 11 Communication unit

[0274] 12, 22, 52 Storage unit

[0275] 13, 23, 55 Control unit

[0276] 20, 30, 40 Base station

[0277] 21, 51 Wireless communication unit

[0278] 53 Network communication unit

[0279] 50 Terminal device

[0280] 54 Input / output unit

[0281] 211 Receive processor

[0282] 211a, 511a Wireless receiver

[0283] 211b, 511b Demultiplexer

[0284] 211c, 511c Demodulator

[0285] 211d, 511d Decoder

[0286] 212 Transmit processor

[0287] 212a, 512a Encoder

[0288] 212b, 512b Modulator

[0289] 212c, 512c Multiplexer

[0290] 212d, 512d Wireless transmitter

[0291] 213, 513 Antenna

[0292] 521, 522, 523 Storage area

[0293] 521a, 522a, 523a HARQ buffer

[0294] ABP1 Airborne platform

[0295] C2 Cell

[0296] CN Core Network

[0297] D1 Radius

[0298] PN Public Network

[0299] R1 Angle

[0300] RAN Radio Access Network

[0301] SBP1, SBP2 Spaceborne Platform

[0302] TN1, TN2 Terrestrial Network

Claims

1. A terminal device, comprising: A communication unit; And A control unit configured to send or receive predetermined data a predetermined number of times to / from a base station device via the communication unit, Wherein the control unit is further configured to send or receive the predetermined data a predetermined number of times in cooperation with another terminal device, and the predetermined data includes data of the terminal device itself or data of the other terminal device; and Wherein the control unit is further configured to: Receive, from the base station device, a transmission resource for transmitting the predetermined data, Divide the transmission resource, Allocate the divided resource to the other terminal device, and Perform cooperative transmission based on the divided transmission resource.

2. The terminal device according to claim 1, wherein the control unit acquires information about a group that is predetermined and includes the other terminal device, and sends or receives the predetermined data a predetermined number of times in cooperation with the other terminal device included in the group.

3. The terminal device according to claim 2, wherein the control unit acquires identification information for identifying the group or identification information for identifying the other terminal device included in the group as information about the group.

4. The terminal device according to claim 1, wherein the control unit issues a dynamic notification to the other terminal device, and the dynamic notification instructs the terminal device to send or receive the predetermined data the predetermined number of times in cooperation.

5. The terminal device according to claim 1, wherein the control unit serves as a master device when the terminal device cooperatively sends data of the terminal device itself, and serves as a slave device when the terminal device cooperatively sends data of the other terminal device.

6. The terminal device according to claim 5, wherein when the terminal device serves as a master device, the control unit sends a notification for requesting the other terminal device to serve as a slave device, and receives a notification regarding whether the other terminal device agrees to serve as a slave device.

7. The terminal device according to claim 5, wherein when the terminal device serves as a master device, the control unit sends the predetermined data to the other terminal device serving as a slave device and sends the predetermined data a predetermined number of times.

8. The terminal device according to claim 7, wherein when the terminal device sends the predetermined data to the other terminal device serving as a slave device, the control unit further notifies information regarding the predetermined number of times.

9. The terminal device according to claim 7, wherein when the terminal device serves as a master device, the control unit sends data that has undergone different encoding processes to each of a plurality of other terminal devices serving as slave devices.

10. The terminal device according to claim 7, wherein when the process of sending or receiving the predetermined data the predetermined number of times in cooperation is successful, and when a release request notification is received from another device, the control unit cancels the relationship between the master device and the slave device.

11. The terminal device according to claim 7, wherein the control unit receives a notification for requesting the terminal device itself to act as a slave device from the other terminal device acting as a master device, and sends a notification to the other terminal device regarding whether the terminal device itself agrees to act as a slave device.

12. The terminal device according to claim 7, wherein when the terminal device acts as a slave device and there is a request for sending another data when the terminal device collaboratively sends the data of the other terminal device acting as a master device, the control unit suspends the data sending process and sends the other data.

13. The terminal device according to claim 7, wherein when the terminal device acts as a slave device, the control unit makes the transport block size (TBS) consistent with the TBS of the other terminal device acting as a master device.

14. The terminal device according to claim 1, wherein the control unit divides the predetermined data, allocates the divided data to the other terminal device, and performs collaborative transmission.

15. The terminal device according to claim 1, wherein the control unit performs processing on the predetermined data, and the processing is associated with the identification ID of the terminal device that is the owner of the predetermined data.

16. A base station device, comprising: a communication unit; and a control unit configured to receive the predetermined data collaboratively sent from a plurality of terminal devices via the communication unit and combine the received predetermined data, wherein the plurality of terminal devices includes the terminal device according to any one of claims 1 - 15 and another terminal device.

17. A control method performed by the terminal device according to any one of claims 1 - 15.

18. A control method performed by the base station device according to claim 16.

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