Communication device and communication method

Abstract

A terminal device, comprising processing circuitry configured to receive a first downlink signal and a first downlink channel from a first communication point, wherein the first downlink channel includes system information, acquire information concerning a common Transmission Configuration Indicator (TCI) state list from the system information, wherein the common TCI state list includes TCI states of a plurality of second communication points and is transmitted as common information to a plurality of terminal devices, receive one or more second downlink signals based on the common TCI state list from at least one of the plurality of second communication points, and perform reception processing for one or more second downlink channels based on the TCI states included in the common TCI state list.

Description

COMMUNICATION DEVICE AND COMMUNICATION METHOD

[0001] The present disclosure relates to a communication device and a communication method.

[0002] Technologies concerning wireless communication have been actively developed. In recent years, multilink connection in which a plurality of transmission and reception points (TRPs) cooperate to communicate with one terminal device in user data communication has been standardized.

[0003] WO 2023 / 112702 A

[0004] It is assumed that reliability of a part of communication is improved by the multilink connection. However, wireless communication with high communication performance (for example, high resource utilization efficiency, a large capacity, high speed, low latency, high reliability, high density, multiple simultaneous connection, power saving, or a low processing load) is not always implemented only by introducing the multilink connection technology into a communication system. For example, the multilink connection technology of the related art does not always enable the multilink communication in all types of communication. For example, in 5G, the multilink communication is limited to user-plane communication (user data communication). For that reason, for example, depending on a location / an environment, it is likely that wireless communication with high communication performance is not implemented.

[0005] Therefore, the present disclosure proposes a communication device and a communication method capable of realizing high communication performance.

[0006] Note that the problem or the object explained above is merely one of a plurality of problems or objects that can be solved or achieved by a plurality of embodiments disclosed in the present specification.

[0007] A terminal device, comprising processing circuitry configured to receive a first downlink signal and a first downlink channel from a first communication point, wherein the first downlink channel includes system information, acquire information concerning a common Transmission Configuration Indicator (TCI) state list from the system information, wherein the common TCI state list includes TCI states of a plurality of second communication points and is transmitted as common information to a plurality of terminal devices, receive one or more second downlink signals based on the common TCI state list from at least one of the plurality of second communication points, and perform reception processing for one or more second downlink channels based on the TCI states included in the common TCI state list.

[0008] Fig. 1 is a diagram for explaining diversification of communication nodes.Fig. 2 is a diagram for explaining an example of necessity of common multilink connection.Fig. 3 is a diagram for explaining an example of the necessity of the common multilink connection.Fig. 4 is a diagram for explaining another example of the necessity of the common multilink connection.Fig. 5 is a diagram illustrating a configuration example of a communication system according to an embodiment.Fig. 6 is a diagram illustrating a configuration of a management device according to the embodiment.Fig. 7 is a diagram illustrating a configuration of a base station according to the embodiment.Fig. 8 is a diagram illustrating a configuration of a relay station according to the embodiment.Fig. 9 is a diagram illustrating a configuration of a terminal device according to the embodiment.Fig. 10 is a diagram illustrating an example of a communication system in the embodiment.Fig. 11 is a diagram for explaining a power concentration technology (point forming) to a specific point.Fig. 12 is a diagram illustrating a point forming example with a single antenna including a large number of antenna elements.Fig. 13 is a diagram for explaining a near field and a far field.Fig. 14 is a diagram illustrating a Fraunhofer distance that is a boundary between the near field and the far field.Fig. 15 is a diagram illustrating an example of point forming in a distributed antenna environment.Fig. 16 is a sequence diagram illustrating an example of initial access processing.Fig. 17 is a diagram illustrating a contention-based random access procedure.Fig. 18 is a diagram illustrating a non-contention-based random access procedure.Fig. 19 is a diagram illustrating a two-step random access procedure.Fig. 20 is a diagram illustrating an example of a form of a plurality of communication points.Fig. 21 is a diagram illustrating another example of a form of a plurality of communication points.Fig. 22 is a sequence diagram illustrating communication processing according to a first example.Fig. 23 is a sequence diagram illustrating communication processing according to a second example.

[0009] Embodiments of the present disclosure are explained in detail below with reference to the drawings. Note that, in the embodiments explained below, redundant explanation is omitted by denoting the same parts with the same reference numerals and signs.

[0010] Also, in the present specification, the expression "at least one of" involving listing of elements is understood as an expression indicating that the listed elements are choices. For example, "at least one of A, B, and C " represents "(A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C)". The "at least one of A, B, or C (at least one of A, B, or C)" and the "at least one of A, B, and / or C (at least one of A, B, and / or C)" are the same as the "at least one of A, B, and C". Here, all of A, B, and C are any expressions (for example, words, phrases, clauses, terms, or items).

[0011] In the present specification and the drawings, a plurality of components having substantially the same functional configuration are sometimes distinguished by adding different numbers after the same reference sign. For example, a plurality of configurations having substantially the same functional configuration is distinguished as communication points P1, P2, and P3as necessary. However, when it is not particularly necessary to distinguish each of the plurality of components having substantially the same functional configuration, only the same reference sign is added. For example, when it is not particularly necessary distinguish the communication points P1, P2, and P3, the communication points P1, P2, and P3are simply referred to as communication point P.

[0012] One or more embodiments (Examples and modifications are included) described below can each be implemented independently. On the other hand, at least some of the plurality of embodiments explained below may be implemented in combination with at least some of other embodiments as appropriate. These plurality of embodiments can include new characteristics different from one another. Therefore, these plurality of embodiments can contribute to solving objects or problems different from one another and can achieve effects different from one another.

[0013] The present disclosure is explained according to the order of items described below. 1. Overview 1-1. Background 1-2. Problems 1-3. Overview of solutions 1-4. Supplementary explanation 2. Configuration of a communication system 2-1. Configuration example of a management device 2-2. Configuration example of a base station 2-3. Configuration example of a relay station 2-4. Configuration example of a terminal device 3. Communication point 3-1. Definition of the communication point 3-2. Specific example of the communication system 3-3. Point forming 4. Initial access control 4-1. Basic procedure 4-2. Random access procedure 5. Operation of the communication system 5-1. Explanation of technical terms 5-2. Overview of an operation of the communication system 5-3. First example 5-4. Second example 5-5. Third example 5-6. Fourth example 6. Modifications 7. Conclusion

[0014] <<1. Overview>> First, an overview in the present embodiment is explained.

[0015] <1-1. Background> Technologies concerning wireless communication such as cellular communication have been actively developed. At present, in 3GPP (registered trademark), discussions for B5G (Beyond 5G) and 6G (6th Generation Mobile Communication System) are started in parallel to 5G specification formulation.

[0016] (Use of a high-frequency band) In cellular communication of the related art, communication control has been performed in units of a communicable range (communication coverage) of one base station (including a TRP (transmission and reception point) called cell. However, in the B5G and the 6G, an operation of a system in a high-frequency band such as a terahertz wave in addition to a millimeter wave is expected. Communication using the high-frequency band has a shorter propagation distance compared with communication using a low-frequency band. Therefore, in the B5G and the 6G, the communicable range (the communication coverage) of the base station is assumed to be smaller than before.

[0017] (Diversification of communication nodes) In addition, in future wireless communication, it is expected that communication nodes will be diversified. Fig. 1 is a diagram for explaining diversification of communication nodes. For example, in the 5G, it is assumed that an overhanging antenna called TRP is used as a communication node in addition to a base station. Further, in the 5G, it is assumed that an IAB (Integrated Access and Backhaul) node (that is, a base station relay) is used as a communication node. Furthermore, in the 5G, it is assumed that an NTN (Non-terrestrial network) node (for example, a communication satellite) is used as a communication node.

[0018] In the B5G and the 6G, it is expected that diversification of communication nodes is further promoted for the purpose of coping with a high-frequency band and / or reducing CAPEX / OPEX. For example, in the B5G and the 6G, it is assumed that a smart repeater including an RIS (Reconfigurable Intelligent Surface) is used as a communication node. In the B5G and the 6G, it is also assumed that an inter-terminal relay or the like is used. Note that the communication node of the related art is either a fully controllable communication node (for example, a base station and / or an IAB node) or a non-controllable communication node (for example, an RF(Radio Frequency)). From now on, however, it is also assumed that a communication node in which some of control items are controllable is used.

[0019] (Multilink connection) In recent years, multilink connection in which a plurality of TRPs (Transmission and reception points) cooperate to communicate with one terminal device in user data communication (UE-dedicated data) has been standardized. It is assumed that reliability of a part of communication (for example, user data communication) is improved by the multilink connection.

[0020] In the following explanation, the multilink connection (or communication using the multilink connection) is sometimes referred to as multilink communication or simply multilink. In addition, "UE-dedicated" appearing in the following explanation can be read as "UE-specific".

[0021] In the 5G, the communication using the high-frequency band is limited to user data communication. Since the communication using the high-frequency band is unstable compared to communication using a low frequency band, there is a strong request for improvement in reliability. Therefore, in the 5G, multilink communication is limited to user-plane communication (user data communication).

[0022] <1-2. Problems> However, wireless communication with high communication performance (for example, high resource utilization efficiency, a large capacity, high speed, low latency, high reliability, high density, multiple simultaneous connection, power saving, or a low processing load) is not always implemented only by introducing the multilink connection technology into a communication system.

[0023] As explained above, in the 5G, the multilink communication is limited to the user-plane communication (the user data communication). Currently, user-plane multilink communication is controlled by control-plane communication. For that reason, the control-plane multilink communication (control information multilink communication) cannot be implemented by the control method of the related art. If the control-plane multilink communication is not implemented, the wireless communication with high communication performance is likely to be not implemented depending on, for example, a location / an environment.

[0024] In the following explanation, the multilink connection capable of not only the user-plane multilink communication (user data multilink communication) but also the control-plane multilink communication (control information multilink communication) is sometimes referred to as common multilink connection. The common multilink connection (or the communication using the common multilink connection) may be referred to as common multilink communication or common multilink.

[0025] In order to supplement this problem, several necessities of the common multilink connection are exemplified below.

[0026] (Necessity of the common multilink connection (a first example)) As explained above, in the 5G, the multilink communication is limited to the user-plane communication (the user data communication). However, in the B5G / the 6G, it is assumed that the multilink connection is important not only in the user-plane communication but also in the control-plane communication (control information communication) for performing authentication, session management, mobility management, or the like.

[0027] Fig. 2 and Fig. 3 are diagrams for explaining an example of the necessity of the common multilink connection. For example, in order to implement ultra-high speed communication in the B5G / the 6G, it is assumed that use of a high-frequency band such as a millimeter wave band is essential. In particular, in a specific location (for example, a location such as the inside a building or under the ground where a radio wave of a macro cell cannot reach) where a demand for ultra-high speed communication is high, it is assumed that a demand for standalone operation (for example, operation independent of the macro cell) by a small cell using a high-frequency band increases. In addition, also in a specific environment (for example, a private network environment) in which the demand for the ultra-high speed communication is high, it is assumed that the demand for the standalone operation by one or a plurality of small cells using a high-frequency band increases.

[0028] When the standalone operation using the high-frequency band is performed, reliability improvement by the multilink connection is requested not only for the user-plane communication (the user data communication) but also for the control-plane communication (control information communication).

[0029] (Necessity of the common multilink connection (a second example)) Fig. 4 is a diagram for explaining another example of the necessity of the common multilink connection. In recent years, the number of small cells supporting a high-frequency band has been increasing. In the related art, control of small cells has been entirely performed by a control unit (for example, a processor such as a CPU) of a macro cell. In this case, since a load on the control unit of the macro cell increases, the number of small cells to be housed is limited.

[0030] In order to solve this problem, it is conceivable that a part or an entire control plane is processed by a control unit (for example, a processor such as a CPU) of the small cell. For example, it is conceivable that a part or entire processing of the control plane is performed by the user plane (transferred to the user plane). If this is implemented, it is assumed that a large number of small cells can be housed.

[0031] However, in order to implement this, it is assumed that support for use of a high-frequency band (for example, support for transmission of control information from the small cell to a terminal device using a high-frequency band) is necessary. Reliability improvement is required for the use of the high-frequency band. For that reason, it is assumed that the multilink connection (for example, multi-TRP communication) on the control plane is necessary. That is, it is assumed that a control method for the common multilink connection is necessary anew.

[0032] <1-3. Overview of solutions> Thus, in the present embodiment, the problems described above are solved as follows.

[0033] For example, a first communication point transmits information concerning a TCI state of one or more second communication points to a terminal device. Here, the first communication point transmits the information concerning the TCI state not as information (UE-dedicated information) individual to one terminal device but as information (common information) common to a plurality of terminal devices. The information concerning the TCI state is, for example, a TCI state list including one or a plurality of TCI states. For example, the information concerning the TCI state is a TCI state list including a TCI state of each of the plurality of second communication points. TCI is an abbreviation of Transmission Configuration Indicator / Indication. In the following explanation, the TCI state list transmitted as the common information is sometimes referred to as common TCI state list.

[0034] Here, the TCI state is information concerning a QCL (Quasi-Co-Location) of a signal and / or a channel. The TCI state may be called spatial reception parameter, spatial relation information, or the like. The TCI state is set in a communication device, for example, for each channel or each signal. The QCL is explained below.

[0035] The communication point is, for example, a communication node (for example, a base station, a relay station, or an antenna) that can be accessed by the terminal device. The communication point may be a cell (for example, a small cell using a high-frequency band) accessible by the terminal device. The first communication point may be one of the plurality of second communication points or may be a communication point different from all of the plurality of second communication points. For example, the second communication point may be one of a plurality of small cells using a high-frequency band and the first communication point may be a macro cell including the small cell. Alternatively, for example, the second communication point may be one of a plurality of small cells using a high-frequency band and the first communication point may be the same cell as the small cell.

[0036] As explained above, the first communication point transmits the information concerning the TCI state to the terminal device. At this time, the first communication point may report the information concerning the TCI state to the terminal device using a first channel. For example, the first communication point may report the information concerning the TCI state using a broadcast channel (for example, BCCH (Broadcast Control Channel)). The information concerning the TCI state may be included in report information reported using the first channel. The report information is, for example, an MIB (Master Information Block) or an SIB (System Information Block).

[0037] The terminal device performs processing concerning communication based on the information (for example, the common TCI state list) concerning the TCI state reported using the first channel. For example, the terminal device performs processing concerning the multilink connection with the plurality of second communication points based on a TCI state of each of the plurality of second communication points. Here, the information concerning the TCI state may include information concerning the QCL. Then, the terminal device may perform the processing concerning the multilink connection based on the information concerning the QCL.

[0038] Accordingly, the terminal device is capable of using the multilink connection from a stage of transmitting and receiving the control information. That is, the multilink connection in the control plane is possible. As a result, wireless communication with high communication performance not depending on a location / an environment is implemented.

[0039] Note that the information concerning the TCI state transmitted as the common information (for example, the common TCI state list) may be used for communication processing other than the processing concerning the multilink connection. For example, the terminal device may perform processing concerning connection to one second communication point based on the common TCI state list. Accordingly, the terminal device is capable of performing communication processing (for example, transmission processing and / or reception processing) based on the TCI state of the second communication point from a stage of transmission and reception of the control information. As a result, wireless communication with high communication performance is implemented.

[0040] <1-4. Supplementary explanation> Before explaining a communication system 1 in the present embodiment in detail, the control plane and the user plane are briefly explained.

[0041] (Control plane) The control plane (also referred to as C-Plane) is a portion that treats control information (a control signal). The control plane mainly manages control information concerning who (what) is performing what kind of communication with which base station. The control plane is in charge of control functions such as authentication, session management, and mobility management. In general, high reliability is required for control-plane communication.

[0042] (User plane) The user plane (also referred to as U-Plane) is a portion that treats user data. For example, the user plane treats content such as sound data. The user plane is in charge of transfer of user data. In general, high speed, a large capacity, and low latency are required for user-plane communication.

[0043] (Significance of C / U separation) In the 5G, a mechanism called "C / U separation" capable of separately managing the control plane (the C-Plane) and the user plane (the U-Plane) is introduced. The introduction of the C / U separation enables an efficient network operation in a transition period (non-standalone (NSA)) in which the 4G and the 5G are mixed. For example, it is possible to perform a flexible operation for using a 4G network covering a wide range in switching control (handover) of a base station and using a 5G network capable of high-speed, large-capacity, and low-latency communication in actual communication.

[0044] The overview in the present embodiment is explained above. The communication system 1 in the present embodiment is explained in detail below.

[0045] <<2. Configuration of the communication system>> First, a configuration of the communication system 1 is explained. Fig. 5 is a diagram illustrating a configuration example of the communication system 1 according to the present embodiment. The communication system 1 includes a management device 10, a base station 20, a relay station 30, and a terminal device 40. The communication system 1 provides a wireless network (a mobile network) capable of mobile communication to a user by wireless communication devices configuring the communication system 1 operating in cooperation.

[0046] The wireless network (the mobile network) in the present embodiment may be, for example, a cellular network / a cell-free network including a radio access network RAN and a core network CN. The cell-free network is a wireless network excluding a cell boundary in a cell configuration (a cellular network) centering on the base station of the related art. Note that the wireless network (the mobile network) may include the terminal device 40. In the present embodiment, the wireless communication device is a device having a function of wireless communication. In the example illustrated in Fig. 5, the base station 20, the relay station 30, and the terminal device 40 correspond to the wireless communication device.

[0047] The communication system 1 may include a plurality of management devices 10, a plurality of base stations 20, a plurality of relay stations 30, and a plurality of terminal devices 40. In the example illustrated in Fig. 5, the communication system 1 includes management devices 101and 102as the management device 10 and includes base stations 201, 202, and 203as the base station 20. The communication system 1 includes relay stations 301and 302as the relay station 30 and includes terminal devices 401, 402, and 403as the terminal device 40.

[0048] The terminal device 40 may be configured to be connected to a network using a radio access technology (RAT) such as LTE (Long Term Evolution), NR (New Radio), B5G (Beyond 5G), 6G, Wi-Fi, Bluetooth (registered trademark). At this time, the terminal device 40 may be configured to be capable of using different radio access technologies (wireless communication schemes). For example, the terminal device 40 may be configured to be capable of using the NR and the Wi-Fi. The terminal device 40 may be configured to be capable of using different cellular communication technologies / cell-free communication technologies (for example, LTE, NR, B5G, or 6G). In the following explanation, the terminal device 40 is sometimes referred to as UE (User Equipment) 40.

[0049] The LTE and the NR are types of the cellular communication technology and enable mobile communication of a terminal device by arranging, in a cell shape, a plurality of areas covered by a device (for example, a base station or a TRP (Transmission and Reception Point)) having an electromagnetic wave transmission and reception function. The B5G and the 6G are likely to be technologies that enable mobile communication of a terminal device as a type of the cellular communication technology / the cell-free communication technology. The cell-free communication technology is a technology excluding a cell boundary in the cellular network of the related art. Note that the cell-free communication technology may be regarded as a type of the cellular communication technology. In this case, the description of "cellular" appearing in the following explanation can be replaced with "cell-free" as appropriate or the description of "cell-free" can be replaced with "cellular" as appropriate.

[0050] Note that, in the following explanation, it is assumed that "LTE" includes LTE-A (LTE-Advanced), LTE-A Pro (LTE-Advanced Pro), and EUTRA (Evolved Universal Terrestrial Radio Access). It is assumed that the NR includes NRAT (New Radio Access Technology) and FEUTRA (Further EUTRA). Note that a single base station or a single TRP may manage one or a plurality of cells. In the following explanation, a cell adapted to the LTE is referred to as an LTE cell and a cell adapted to the NR is referred to as an NR cell.

[0051] The NR is a radio access technology of the next generation (a fifth generation) of the LTE (fourth generation communication including LTE-Advanced and LTE-Advanced Pro). The NR is a radio access technology that can cope with various use cases including eMBB (Enhanced Mobile Broadband), mMTC (Massive Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communications). The NR was formulated as a standard after Rel-15 of 3GPP (registered trademark) as a technical framework adapted to use scenarios, requirement conditions, arrangement scenarios, and the like in these use cases. In the 3GPP, technologies for the next generation including enhancement of the NR standard are studied. For example, in Rel-19, standardization activities for 6G (B5G (Beyond 5G)), which is a next-generation communication standard, are performed.

[0052] The 6G is a cellular communication technology / a cell-free communication technology of the next generation of the NR or the 5GS (5G system) that is the fifth generation mobile communication. In the 6G, it is requested to simultaneously implement a plurality of axes of high speed and large capacity, low latency and high reliability, and multiple simultaneous connection. The 6G includes a radio access technology and a network technology among a base station, a core network, and a data network. The 6G includes a technology for extreme connectivity of each of eMBB, mMTC, and URLLC, which are main use cases or requirements in the NR. The 6G includes new technologies in new aspects. For example, the 6G can include technologies concerning AI (Cognitive network, AI native Air Interface) and sensing (including Rader / RF sensing, network as a sensor) terahertz communication.

[0053] Note that the wireless network explained above or explained below may be adapted to at least one of radio access technologies (RATs) such as LTE, NR, B5G, and 6G. The LTE, the NR, the B5G, and the 6G are types of the cellular communication technology / the cell-free communication technology. Note that the radio access scheme used by the communication system 1 is not limited to the LTE, the NR, the B5G, and the 6G and may be another radio access scheme such as W-CDMA (Wideband Code Division Multiple Access) or cdma2000(Code Division Multiple Access 2000).

[0054] The base station 20 and the relay station 30 may be ground stations or may be non-ground stations. The non-ground station may be a satellite station or may be an aircraft station. If the non-ground station is a satellite station, the wireless network may be a Bent-pipe (Transparent) type mobile satellite communication system.

[0055] In the present embodiment, the ground station and the ground base station refer to a base station and a relay station installed on the ground. Here, the "ground" is a ground in a broad sense including not only the land but also underground, on water, and underwater. Note that, in the following explanation, the description of "ground station" may be replaced with "gateway".

[0056] Note that a base station of the LTE is sometimes referred to as eNodeB (Evolved Node B) or eNB. A base station of the NR is sometimes referred to as gNodeB or gNB. A base station of the 6G is sometimes referred to as 6G NodeB (6GNB). In the LTE, the NR, and the 6G, a terminal device (referred to as a mobile station or a terminal) is sometimes referred to as user equipment (UE). Note that the terminal device is a type of a communication device and is also referred to as mobile station or terminal.

[0057] Note that the terminal device 40 may be connectable to a network using a radio access technology (a wireless communication scheme) other than the LTE, the NR, the B5G, the 6G, the Wi-Fi, and the Bluetooth. For example, the terminal device 40 may be connectable to a network by using LPWA (Low Power Wide Area) communication. The terminal device 40 may be connectable to a network using original standard wireless communication.

[0058] Here, the LPWA communication refers to wireless communication that enables low-power wide-range communication. For example, LPWA radio refers to IoT (Internet of Things) wireless communication using a specific low power radio (for example, a 920 MHz band) or an ISM (Industry-Science-Medical) band. The LPWA radio may include LTE-M operating in a cellular frequency band and / or C-IoT (Cellular IoT) represented by NB-IoT. Note that the LPWA communication used by the terminal device 40 may conform to the LPWA standard. The LPWA standard may be, for example, at least one of ELTRES, ZETA, SIGFOX, LoRaWAN, LTE-M, and NB-IoT. Naturally, the LPWA standard is not limited thereto and may be another LPWA standard.

[0059] The wireless communication devices illustrated in Fig. 5 may be considered devices in a logical sense. That is, some of the wireless communication devices may be implemented by a virtual machine (VM), a container such as a docker, and the like, and those may be physically implemented on the same hardware.

[0060] In the present embodiment, the concept of the wireless communication device includes not only a portable mobile device (terminal device) such as a mobile terminal but also a device installed in a structure or a mobile body. The structure or the mobile body itself may be regarded as a wireless communication device. The concept of the wireless communication device includes not only the terminal device 40 but also the base station 20 and the relay station 30. The wireless communication device is a type of a processing device or an information processing device. The wireless communication device can also be referred to as transmission device or reception device.

[0061] Hereinafter, configurations of the wireless communication devices configuring the communication system 1 are specifically explained. Note that the configurations of the wireless communication devices explained below is only an example. The configurations of the wireless communication devices may be different from the configurations explained below.

[0062] <2-1. Configuration example of the management device> Subsequently, a configuration example of the management device 10 is explained.

[0063] The management device 10 is an information processing device (a computer) that manages a wireless network. For example, the management device 10 is an information processing device that manages communication of the base station 20.

[0064] The management device 10 may be a device configuring the core network CN. For example, the management device 10 may be a device having a function serving as an MME (Mobility Management Entity). The management device 10 may be a device having a function of an AMF (Access and Mobility Management Function) and / or an SMF (Session Management Function). The MME, the AMF, and the SMF are control plane network function nodes in the core network CN. The management device 10 may be a device having a function serving as a control plane network function (6G CPNF) in the 6G. The 6G CPNF may include one or a plurality of logical nodes.

[0065] Naturally, the functions of the management device 10 are not limited to the MME, the AMF, the SMF, and the 6G CPNF. The management device 10 may be a device having a function serving as an NSSF (Network Slice Selection Function), an AUSF (Authentication Server Function), a PCF (Policy Control Function), and a UDM (Unified Data Management). The management device 10 may be a device having a function of an HSS (Home Subscriber Server).

[0066] Note that the management device 10 may have a function of a gateway. For example, the management device 10 may have a function of a S-GW (Serving Gateway) or a P-GW (Packet Data Network Gateway). The management device 10 may have a function serving as a UPF (User Plane Function). At this time, the management device 10 may have a plurality of UPFs. The management device 10 may be a device having a function serving as a user plane network function (6G UPNF) in the 6G.

[0067] The core network CN includes a plurality of network functions. The network functions may be aggregated into one physical device or distributed to a plurality of physical devices. That is, the management device 10 can be distributed and disposed in a plurality of devices. Further, this distributed disposition may be controlled to be dynamically executed. The base station 20, the relay station 30, and the management device 10 configure one network and provide a wireless communication service to the terminal device 40. The management device 10 is connected to the Internet. The terminal device 40 can use, via the base station 20 and / or the relay station 30, various services provided via the Internet.

[0068] Note that the management device 10 may not always be a device configuring the core network CN. For example, it is assumed that the core network CN is a core network of W-CDMA (Wideband Code Division Multiple Access) or cdma2000 (Code Division Multiple Access 2000)). At this time, the management device 10 may be a device functioning as an RNC (Radio Network controller).

[0069] Fig. 6 is a diagram illustrating a configuration of the management device 10 according to the present embodiment. The management device 10 includes a communication unit 11, a storage unit 12, and a control unit 13. The configuration illustrated in Fig. 6 is a functional configuration. A hardware configuration may be different from the configuration. The functions of the management device 10 may be statically or dynamically distributed and implemented in a plurality of physically separated components. The management device 10 may include a plurality of server devices.

[0070] The communication unit 11 is a communication interface for communicating with a wireless communication device (for example, the base station 20). The communication unit 11 may be a network interface or may be an equipment connection interface. The communication unit 11 may be a LAN (Local Area Network) interface such as an NIC (Network Interface Card), a USB (Universal Serial Bus) host control unit, or a USB interface including a USB port or the like. The communication unit 11 may be a wired interface or may be a wireless interface. The communication unit 11 is controlled by the control unit 13.

[0071] The storage unit 12 is a readable and writable storage device such as a DRAM, an SRAM, a flash memory, or a hard disk. The storage unit 12 stores, for example, a connection state of the terminal device 40. The storage unit 12 stores a state of RRC (Radio Resource Control) and a state of ECM (EPS Connection Management) or 5G System CM (Connection Management) of the terminal device 40. The storage unit 12 may function as a home memory that stores location information of the terminal device 40.

[0072] The control unit 13 is a control unit that controls the units of the management device 10. The control unit 13 may be implemented by a processor such as a CPU or an MPU. Specifically, the control unit 13 may be implemented by the processor executing, using a RAM or the like as a work area, various programs stored in a storage device on the inside of the management device 10. The control unit 13 may be implemented by an integrated circuit such as an ASIC or an FPGA. The control unit 13 may be implemented by a GPU. All of the CPU, the MPU, the ASIC, the FPGA, and the GPU can be regarded as a control unit. Note that the control unit 13 may include a plurality of physically separated objects. For example, the control unit 13 may include a plurality of semiconductor chips.

[0073] Note that an operation of the control unit 13 may be the same as an operation of a control unit (a control unit 23, a control unit 33, or a control unit 43) of the base station 20, the relay station 30, or the terminal device 40.

[0074] <2-2. Configuration example of the base station> Subsequently, a configuration example of the base station 20 is explained.

[0075] The base station 20 is a wireless communication device that performs wireless communication with other wireless communication devices (for example, the relay station 30, the terminal device 40, or another base station 20). The base station 20 may wirelessly communicate with the terminal device 40 via the relay station 30 or may directly wirelessly communicate with the terminal device 40.

[0076] The base station 20 is a device equivalent to a wireless base station (for example, Base Station, Node B, eNB, gNB, or 6GNB) or a wireless access point. In the following explanation, the base station 20 is sometimes called BS (Base Station), Node B, eNB, gNB, 6GNB, or BS20.

[0077] The base station 20 may be a wireless relay station (for example, the relay station 30 explained below). The base station 20 may be an optical extension device called RRH (Remote Radio Head). The base station 20 may be a reception station such as an FPU (Field Pickup Unit). The base station 20 may be an IAB (Integrated Access and Backhaul) donor node or an IAB relay node that provides radio access lines and radio backhaul lines in time division multiplexing, frequency division multiplexing, or space division multiplexing.

[0078] The radio access technology used by the base station 20 may be a cellular communication technology / a cell-free communication technology. The radio access technology used by the base station 20 may be a wireless LAN technology. The radio access technology used by the base station 20 may be an LPWA (Low Power Wide Area) communication technology. However, the radio access technology used by the base station 20 is not limited thereto and may be another radio access technology. The wireless communication used by the base station 20 may be wireless communication using a millimeter wave or wireless communication using a terahertz wave. The wireless communication used by the base station 20 may be wireless communication using a radio wave or wireless communication (optical radio) using ab infrared ray or visible light. The base station 20 may be capable of performing NOMA (Non-Orthogonal Multiple Access) communication with the terminal device 40. Here, the NOMA communication refers to communication (transmission, reception, or both of transmission and reception) in which non-orthogonal resources are used. Note that the base station 20 may be capable of performing the NOMA communication with the other base stations 20.

[0079] Note that the base station 20 may be capable of communicating with a core network via a base station-core network interface (for example, an NG Interface or an S1 Interface). This interface may be either wired or wireless. The base station may be capable of communicating with other base stations via an inter-base station interface (for example, an Xn Interface, an X2 Interface, or an F1 Interface). This interface may be either wired or wireless.

[0080] The concept of a base station (also referred to as "base station device") includes not only a donor base station but also a relay base station (also referred to as "relay station"). The relay base station may be any one of an RF Repeater, a Smart Repeater, and an Intelligent Surface. The concept of the base station may include a roadside unit (RSU). The concept of the base station may include not only a structure having a function of the base station but also a device installed in the structure.

[0081] The structure is a building such as a high-rise building, a house, a steel tower, a station facility, an airport facility, a port facility, an office building, a school building, a hospital, a factory, a commercial facility, or a stadium. The concept of the structure includes not only a building but also non-building structures such as a tunnel, a bridge, a dam, a wall, and an iron pillar and equipment such as a crane, a gate, and a windmill. The concept of the structure includes not only a structure on the land (on the ground in a narrow sense) or in the ground but also a structure on water such as a pier or a mega-float, and a structure under water such as an marine observation facility. The base station can also be referred to as information processing device.

[0082] The base station 20 may be a donor station or may be a relay station (a relay station). The base station 20 may be a fixed station or a mobile station. The mobile station is a wireless communication device (for example, a base station) configured to be movable. At this time, the base station 20 may be a device installed in a mobile body or may be the mobile body itself. For example, a relay station having mobility can be regarded as the base station 20 functioning as a mobile station. A device originally having mobility and implemented with a function of a base station (at least some of functions of the base station) such as a vehicle, a UAV (Unmanned Aerial Vehicle) represented by a drone, or a smartphone also corresponds to the base station 20 functioning as the mobile station.

[0083] Here, the mobile body may be a mobile terminal such as a smartphone or a mobile phone. The mobile body may be a mobile body (for example, a vehicle such as an automobile, a bicycle, a bus, a truck, a motorcycle, a train, or a linear motor car) that moves on the land (on the ground in a narrow sense) or a mobile body (for example, a subway) that moves in the ground (for example, in a tunnel). The mobile body may be a mobile body (for example, a ship such as a passenger ship, a cargo ship, or a hovercraft) that moves on the water or a mobile body (for example, a submersible such as a submersible boat, a submarine, or an unmanned submersible) that moves under the water. The mobile body may be a mobile body (for example, an aircraft such as an airplane, an airship, or a drone) that moves within the atmosphere.

[0084] The base station 20 may be a ground base station (a ground station) installed on the ground. The base station 20 may be a base station disposed in a structure on the ground or may be a base station installed in a mobile body moving on the ground. The base station 20 may be an antenna installed in a structure such as a building and a signal processing device connected to the antenna. The base station 20 may be the structure or the mobile body itself. The "ground" is not only the land (the ground in a narrow sense) but also the ground in a broad sense including under the ground, in the water, and under the water. The base station 20 is not limited to the ground base station. When the communication system 1 is a satellite communication system, the base station 20 may be an aircraft station. When viewed from a satellite station, an aircraft station located on the earth is the ground station.

[0085] The base station 20 is not limited to the ground station. The base station 20 may be a non-ground base station (a non-ground station) capable of floating in the air or the space. The base station 20 may be an aircraft station or a satellite station.

[0086] A satellite station is a wireless communication device capable of floating outside the atmosphere. The satellite station may be a device mounted on a space mobile body such as an artificial satellite or may be the space mobile body itself. The space mobile body is a mobile body that moves outside the atmosphere. The space mobile body may be at least one of an artificial satellite, a spacecraft, a space station, and a probe. Naturally, the space mobile body may be an artificial heavenly body other than the above. Note that a satellite serving as the satellite station may be any of a Low Earth Orbiting (LEO) satellite, a Medium Earth Orbiting (MEO) satellite, a Geostationary Earth Orbiting (GEO) satellite, or a Highly Elliptical Orbiting (HEO) satellite. The satellite station may be a device mounted on the low earth orbiting satellite, the middle earth orbiting satellite, the geostationary earth orbiting satellite, or the highly elliptical orbiting satellite.

[0087] The aircraft station is a wireless communication device capable of floating within the atmosphere such as an aircraft. The aircraft station may be a device mounted on the aircraft or the like or may be the aircraft itself. The concept of the aircraft includes not only a heavy aircraft such as an airplane or a glider but also a light aircraft such as a balloon or an airship. The concept of the aircraft includes not only the heavy aircraft or the light aircraft but also a rotorcraft such as a helicopter or an auto-gyro. The aircraft station or the aircraft on which the aircraft station is mounted may be an unmanned aircraft such as a drone.

[0088] The concept of an unmanned aerial vehicle also includes an unmanned aircraft system (UAS) and a tethered UAS. The concept of unmanned aerial vehicles includes Lighter than Air UAS (LTA) and Heavier than Air UAS (HTA). The concept of unmanned aerial vehicles also includes High Altitude UAS Platforms (HAPs).

[0089] The coverage of the base station 20 may be a relatively large one such as a macro cell or may be a relatively small one such as a pico cell. The coverage of the base station 20 may be an extremely small one such as a femtocell. The base station 20 may have a beamforming function. In the base station 20, a cell or a service area may be formed for each beam. Further or alternatively, the base station 20 may have, in addition to beamforming for imparting directivity to a beam, a function of delivering a desired wave to a predetermined point with pinpoint accuracy by further considering distance information from an antenna of the base station 20. This function may be called beam focusing or point forming. The base station 20 may be configured to acquire sensing data by performing sensing using a beam.

[0090] Fig. 7 is a diagram illustrating a configuration of the base station 20 according to the present embodiment. The base station 20 includes a wireless communication unit 21, a storage unit 22, and a control unit 23. However, the configuration illustrated in Fig. 7 is a functional configuration. A hardware configuration may be different from the configuration. The functions of the base station 20 may be distributed and implemented in a plurality of physically separated components.

[0091] Note that the base station 20 does not always have all of the components explained above or below. The base station 20 may have components other than the components explained above or below.

[0092] The wireless communication unit 21 is a signal processing unit for wirelessly communicating with another wireless communication device (for example, at least one of the terminal device 40 and the other base station 20). The wireless communication unit 21 may be referred to as wireless transceiver or simply referred to as transceiver. At this time, the wireless communication unit 21 may be a transceiver (hereinafter referred to as 3GPP transceiver) having specifications defined by a technical specification (TS) of 3GPP (3rd Generation Partnership Project). The 3GPP transceiver may be a 3G transceiver, may be a 4G (LTE) transceiver, may be a 5G (NR) transceiver, or may be a 5G or later generation (for example, 6G) transceiver. The wireless communication unit 21 is controlled by the control unit 23. The wireless communication unit 21 is adapted to one or a plurality of radio access schemes. The wireless communication unit 21 may be adapted to at least one of the NR, the LTE, the B5G (Beyond 5G), and the 6G. The wireless communication unit 21 may be adapted to W-CDMA, cdma2000, and the like in addition to the NR, the LTE, the B5G, and the 6G. The wireless communication unit 21 may be adapted to an automatic retransmission technology such as HARQ (Hybrid Automatic Repeat reQuest). A part or all of kinds of processing executed by the wireless communication unit 21 may be executed by the control unit 23.

[0093] The wireless communication unit 21 includes a transmission processing unit 211, a reception processing unit 212, and an antenna 213. Alternatively, the wireless communication unit 21 may regard at least one of the transmission processing unit 211, the reception processing unit 212, and the antenna 213 as the wireless communication unit 21. The wireless communication unit 21 may include a plurality of transmission processing units 211, a plurality of reception processing units 212, and a plurality of antennas 213. When the wireless communication unit 21 is adapted to a plurality of radio access schemes, the units of the wireless communication unit 21 may be configured individually for each of the radio access schemes. The transmission processing unit 211 and the reception processing unit 212 may be individually configured for the LTE, the NR, the B5G, and the 6G. The antenna 213 may include a plurality of antenna elements, for example, a plurality of patch antennas. The wireless communication unit 21 may have a beamforming function. For example, the wireless communication unit 21 may have a polarization beamforming function using vertically polarized waves (V-polarized waves) and horizontally polarized waves (H-polarized waves) (or a polarization beamforming function using dual polarized waves in polarization directions of 45 degrees and -45 degrees from the vertical direction). Note that the wireless communication unit 21 may transmit a sensing signal explained above or below.

[0094] The transmission processing unit 211 performs transmission processing for downlink control information and downlink data. For example, the transmission processing unit 211 encodes the downlink control information and the downlink data input from the control unit 23 using an encoding scheme such as block encoding, convolutional encoding, or turbo encoding. Here, as the encoding, encoding by a polar code or encoding by an LDPC code (Low Density Parity Check Code) may be performed. Then, the transmission processing unit 211 modulates encoded bits with a predetermined modulation scheme (for example, BPSK, QPSK, 16QAM, 64QAM, 256QAM, or a higher order multi-value modulation scheme). In this case, signal points on a constellation do not always need to be equidistant. Furthermore, the constellation may be a non-uniform constellation (NUC). Then, the transmission processing unit 211 multiplexes modulation symbols of channels and a downlink reference signal and disposes the multiplexed symbols and the multiplexed downlink reference signal in a predetermined resource element. Then, the transmission processing unit 211 performs various kinds of signal processing on the multiplexed signal. For example, the transmission processing unit 211 performs processing such as conversion into a frequency domain by fast Fourier transform, addition of a guard interval (a cyclic prefix), generation of a baseband digital signal, conversion into an analog signal, quadrature modulation, up-conversion, removal of an extra frequency component, and amplification of electric power. A signal generated by the transmission processing unit 211 is transmitted from the antenna 213.

[0095] The reception processing unit 212 performs processing for an uplink signal received via the antenna 213. For example, the reception processing unit 212 performs, on the uplink signal, down-conversion, removal of an unnecessary frequency component, control of an amplification level, quadrature demodulation, conversion into a digital signal, removal of a guard interval (a cyclic prefix), extraction of a frequency domain signal by fast Fourier transform, and the like. Then, the reception processing unit 212 separates uplink channels such as a PUSCH (Physical Uplink Shared Channel) and a PUCCH (Physical Uplink Control Channel) and an uplink reference signal from the signals subjected to these kinds of processing. The reception processing unit 212 demodulates the received signal using a modulation scheme such as BPSK (Binary Phase Shift Keying) or QPSK (Quadrature Phase Shift Keying) with respect to a modulation symbol of the uplink channels. The modulation scheme used for the demodulation may be 16QAM (Quadrature Amplitude Modulation), 64QAM, or 256QAM. In this case, signal points on a constellation do not always need to be equidistant. The constellation may be a non-uniform constellation (NUC). The reception processing unit 212 performs decoding processing on encoded bits of the demodulated uplink channels. Decoded uplink data and uplink control information are output to the control unit 23.

[0096] The antenna 213 is an antenna device that mutually converts an electric current and a radio wave. The antenna 213 may include one antenna element, for example, one patch antenna. The antenna 213 may include a plurality of antenna elements, for example, a plurality of patch antennas. When the antenna 213 includes a plurality of antenna elements, the wireless communication unit 21 may have a beamforming function. The wireless communication unit 21 may be configured to generate a directional beam by controlling the directivity of a wireless signal using the plurality of antenna elements. The antenna 213 may be a dual-polarized antenna. When the antenna 213 is the dual-polarized antenna, the wireless communication unit 21 may use a vertically polarized wave (V-polarized wave) and a horizontally polarized wave (H-polarized wave) (or dual polarized waves in polarization directions of 45 degrees and -45 degrees from the vertical direction) when transmitting the wireless signal. The wireless communication unit 21 may control the directivity of the wireless signal transmitted using the vertically polarized waves and the horizontally polarized wave (or the dual polarized waves in the polarization directions of 45 degrees and -45 degrees from the vertical direction). The wireless communication unit 21 may transmit and receive a spatially multiplexed signal via a plurality of layers including a plurality of antenna elements.

[0097] The storage unit 22 is a readable / writable storage device such as a DRAM, an SRAM, a flash memory, or a hard disk.

[0098] The control unit 23 is a control unit that controls the units of the base station 20. The control unit 23 controls the wireless communication unit to carry out wireless communication with another wireless communication device (for example, the relay station 30, the terminal device 40, or another base station 20). The control unit 23 may be implemented by a processor such as a CPU or an MPU. Specifically, the control unit 23 may be implemented by the processor executing, using a RAM or the like as a work area, various programs stored in a storage device on the inside of the base station 20. The control unit 23 may be implemented by an integrated circuit such as an ASIC or an FPGA. The control unit 23 may be implemented by a GPU. All of the CPU, the MPU, the ASIC, the FPGA, and the GPU can be regarded as a control unit. Note that the control unit 23 may include a plurality of physically separated objects. For example, the control unit 23 may include a plurality of semiconductor chips.

[0099] The control unit 23 includes at least one block of an acquisition unit 231, a transmission control unit 232, a reception control unit 233, and a communication control unit 234. The control unit 23 may include a plurality of each of these blocks or may include only one each of these blocks.

[0100] The blocks (the acquisition unit 231 to the communication control unit 234) configuring the control unit 23 are respectively functional blocks indicating functions of the control unit 23. These functional blocks may be software blocks or may be hardware blocks. For example, each of the functional blocks explained above may be one software module implemented by software (including a microprogram) or may be one circuit block on a semiconductor chip (a die). Naturally, each of the functional blocks may be one processor or one integrated circuit. The control unit 23 may be configured in functional units different from the functional blocks. A configuration method for the functional blocks is optional. Note that an operation of the control unit 23 may be the same as the operation of the control unit (the control unit 13, the control unit 33, or the control unit 43) of the management device 10, the relay station 30, or the terminal device 40.

[0101] Note that, in some embodiments, the base station 20 may include a set of a plurality of physical or logical devices. As an example, the base station 20 in the present embodiment may be distinguished into a plurality of devices such as a BBU (Baseband Unit) and an RU (Radio Unit). The base station 20 may be interpreted as a set of these plurality of devices. The base station may be either the BBU or the RU or may be both of the BBU and the RU. The BBU and the RU may be connected by a predetermined interface such as an eCPRI (enhanced Common Public Radio Interface).

[0102] The RU may be referred to as RRU (Remote Radio Unit) or RD (Radio DoT). The RU may be adapted to a gNB-DU (gNB Distributed Unit) explained below. The BBU may be adapted to a gNB-CU (gNB Central Unit) explained below. The RU may be a device formed integrally with an antenna. An antenna of the base station 20, for example, the antenna formed integrally with the RU, may adopt an Advanced Antenna System and support Multiple-Input Multiple-Output (MIMO) such as FD-MIMO or beamforming. The antenna of the base station 20 may include, for example, sixty-four transmission antenna ports and sixty-four reception antenna ports.

[0103] The antenna mounted on the RU may be an antenna panel configured from one or more antenna elements. The RU may be mounted with one or more antenna panels. The RU may be mounted with two types of antenna panels, that is, a horizontally polarized antenna panel and a vertically polarized antenna panel. The RU may be mounted with two types of antenna panels, that is, a right-handed circularly polarized antenna panel and a left-handed circularly polarized antenna panel or an antenna panel in a polarization direction of 45 degrees from the vertical direction and an antenna panel in a polarization direction of -45 degrees from the vertical direction. The plurality of antennas having the plurality of polarization directions may be mounted on one antenna panel. The RU may form and control an independent beam for each of the antenna panels.

[0104] A plurality of the base stations 20 may be connected to one another. The one or plurality of base stations 20 may be included in a radio access network (RAN). At this time, the base station 20 is sometimes simply referred to as RAN, RAN node, access network (AN), AN node, or the like. The RAN in the LTE is sometimes called EUTRAN (Enhanced Universal Terrestrial RAN). The RAN in the NR is sometimes called NGRAN. The RAN in the 6G is sometimes called 6GRAN. The RAN in the W-CDMA (UMTS) is sometimes called UTRAN.

[0105] The base station 20 in the LTE is sometimes called eNodeB (Evolved Node B) or an eNB. At this time, the EUTRAN includes one or a plurality of eNodeBs (eNBs). The base station 20 in the NR is sometimes referred to as gNodeB or gNB. At this time, the NGRAN includes one or a plurality of gNBs. A base station in the 6G is sometimes referred to as 6GNodeB, 6gNodeB, 6GNB, or 6gNB. At this time, the 6GRAN includes one or a plurality of 6GNBs. The EUTRAN may include a gNB (en-gNB) connected to a core network (EPC) in a communication system (EPS) in the LTE. The NGRAN may include an ng-eNB connected to a core network 5GC in a 5G communications system (5GS).

[0106] When the base station 20 is an eNB, a gNB, a 6GNB, or the like, the base station 20 is sometimes referred to as 3GPP access. When the base station 20 is a radio access point (Access Point), the base station 20 is sometimes referred to as non-3GPP access. The base station 20 may be an optical extension device called RRH (Remote Radio Head). When the base station 20 is the gNB, the base station 20 may be a combination of the gNB-CU and the gNB-DU explained above or may be either the gNB-CU or the gNB-DU.

[0107] Here, the gNB-CU hosts, for communication with the UE, a plurality of upper layers (for example, RRC (Radio Resource Control), SDAP (Service Data Adaptation Protocol), and PDCP (Packet Data Convergence Protocol)) among access stratums. On the other hand, the gNB-DU hosts a plurality of lower layers (for example, RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer)) among the access stratums. That is, among messages / information explained below, RRC signaling (a quasi-static notification) may be generated by the gNB-CU and, on the other hand, MAC CE and DCI (a dynamic notification) may be generated by the gNB-DU. Alternatively, among RRC configurations (quasi-static notifications), for example, some of the configurations such as IE: cellGroupConfig may be generated by the gNB-DU and the remaining configurations may be generated by the gNB-CU. These configurations may be transmitted or received by the F1 interface.

[0108] The base station 20 may be configured to be capable of communicating with other base stations. When the plurality of base stations 20 are a combination of eNBs or eNBs and en-gNBs, these base stations 20 may be connected by an X2 interface. When the plurality of base stations 20 are a combination of gNBs or gn-eNBs and gNBs, these base stations 20 may be connected by an Xn interface. When the plurality of base stations 20 are a combination of gNB-CUs and gNB-DUs, these base stations 20 may be connected by the F1 interface explained above. A message / information (for example, RRC signaling, MAC CE (MAC Control Element), or DCI (Downlink Control Information)) explained below may be transmitted among the plurality of base stations 20 via any of these inter-base station interfaces (for example, the X2 interface, the Xn interface, or the F1 interface).

[0109] A cell provided by the base station 20 is sometimes called serving cell. The concept of the serving cell includes a PCell (Primary Cell) and an SCell (Secondary Cell). When dual connectivity is provided to the terminal device 40, the PCell provided by an MN (Master Node) and zero or one or more SCells are sometimes called master cell group. The dual connectivity may be at least one of EUTRA-EUTRA Dual Connectivity, EUTRA-NR Dual Connectivity (ENDC), EUTRA-NR Dual Connectivity with 5 GC, NR-EUTRA Dual Connectivity (NEDC), NR-NR Dual Connectivity, NR-6G Dual Connectivity, and 6G-NR Dual Connectivity. Naturally, the dual connectivity is not limited thereto.

[0110] The serving cell may include a PSCell (Primary Secondary Cell or Primary SCG Cell). When the dual connectivity is provided to the terminal device 40, the PSCell provided by a secondary node (SN) and zero or one or more SCells are sometimes called SCG (Secondary Cell Group). Unless special setting (for example, PUCCH on SCell) is performed, a physical uplink control channel (PUCCH) is transmitted by the PCell and the PSCell but is not transmitted by the SCell. The radio link failure is detected by the PCell and the PSCell but is not detected (may not be detected) by the SCell. As explained above, since the PCell and the PSCell play special roles in the serving cell, the PCell and the PSCell are also called SpCell (Special Cell).

[0111] One downlink component carrier and one uplink component carrier may be associated with one cell. A system bandwidth corresponding to one cell may be divided into a plurality of BWPs (Bandwidth Parts). At this time, one or a plurality of BWPs may be set in the terminal device 40 and one BWP may be used in the terminal device 40 as an active BWP. A radio resource, for example, a frequency band, a numerology (subcarrier spacing), or a slot format (Slot configuration) that can be used by the terminal device 40 may be different for each cell, each component carrier, or each BWP.

[0112] <2-3. Configuration example of the relay station> Subsequently, a configuration example of the relay station 30 is explained.

[0113] The relay station 30 is a wireless communication device serving as a repeater of the base station 20. The relay station 30 is a type of a base station (for example, the base station 20 explained above). The relay station 30 is a type of an information processing device. The relay station 30 can also be referred to as relay base station. Note that the relay station 30 may be a device called repeater (for example, RF Repeater, Smart Repeater, or Intelligent Surface). The relay station 30 is a wireless communication device that performs wireless communication with another wireless communication device (for example, the base station 20, the terminal device 40, or another relay station 30).

[0114] The relay station 30 may be capable of performing NOMA communication with the terminal device 40. The relay station 30 relays communication between the base station 20 and the terminal device 40. The relay station 30 may be capable of performing wireless communication with another relay station 30 and the base station 20. The relay station 30 may be a ground station device or may be a non-ground station device. The relay station 30 configures a radio access network RAN in conjunction with the base station 20.

[0115] The relay station 30 may be a fixed device, may be a movable device, or may be a floatable device. The size of the coverage of the relay station 30 is not limited to a specific size. A cell covered by the relay station 30 may be a macro cell or may be a small cell.

[0116] As long as a relay function is satisfied, a device on which the relay station 30 is mounted is not limited to a specific device. The relay station 30 may be mounted on a terminal device such as a smartphone, may be mounted on an automobile, a train, a man-powered vehicle, or the like, may be mounted on a balloon, an airplane, a drone, or the like, or may be mounted on a home electric appliance such as a television, a game machine, an air conditioner, a refrigerator, or a lighting fixture. A device having the relay function may be regarded as the relay station 30 itself.

[0117] A configuration of the relay station 30 may be the same as the configuration of the base station 20 explained above. Like the base station 20 explained above, the relay station 30 may be a device installed in a mobile body or may be the mobile body itself. As explained above, the mobile body may be a mobile terminal such as a smartphone or a mobile phone. The mobile body may be a mobile body that moves on the land (on the ground in a narrow sense) or may be a mobile body that moves in the ground. The mobile body may be a mobile body that moves on the water or may be a mobile body that moves under the water. The mobile body may be a mobile body that moves inside the atmosphere or may be a mobile body that moves outside the atmosphere. The relay station 30 may be a ground station device or may be a non-ground station device. The relay station 30 may be an aircraft station, a satellite station, or the like.

[0118] Like the base station 20, the coverage of the relay station 30 may be a large one such as a macro cell to a small one such as a pico cell. The coverage of the relay station 30 may be an extremely small one such as a femtocell. The relay station 30 may have a beamforming function. At this time, in the relay station 30, a cell or a service area may be formed for each beam. The relay station 30 may have a point forming function. At this time, in the relay station 30, a cell or a service area may be formed for each point.

[0119] Fig. 8 is a diagram illustrating a configuration of the relay station 30 according to the present embodiment. The relay station 30 includes a wireless communication unit 31, a storage unit 32, and a control unit 33. However, the configuration illustrated in Fig. 8 is functional configuration. A hardware configuration may be different from the configuration. The functions of the relay station 30 may be distributed and implemented in a plurality of physically separated components.

[0120] Note that the relay station 30 does not always need to include all the components explained above or below. The relay station 30 may include components other than the components explained above and below.

[0121] The wireless communication unit 31 is a signal processing unit for wirelessly communicating with another wireless communication device (for example, at least one of the terminal device 40 and the another relay station 30). The wireless communication unit 31 may be referred to as wireless transceiver or simply referred to as transceiver. At this time, the wireless communication unit 31 may be a transceiver (hereinafter referred to as 3GPP transceiver) having specifications defined in the technical specifications of the 3GPP. The 3GPP transceiver may be a 3G transceiver, may be a 4G (LTE) transceiver, may be a 5G (NR) transceiver, or may be a 5G or later generation (for example, 6G) transceiver. The wireless communication unit 31 is controlled by the control unit 33. The wireless communication unit 31 is adapted to one or a plurality of radio access schemes. The wireless communication unit 31 may be adapted to at least one of the NR, the LTE, the B5G, and the 6G. The wireless communication unit 31 may be adapted to W-CDMA, cdma3000, and the like in addition to the NR, the LTE, the B5G, and the 6G. The wireless communication unit 31 may be adapted to an automatic retransmission technology such as HARQ. A part or all of the kinds of processing executed by the wireless communication unit 31 may be executed by the control unit 33.

[0122] The wireless communication unit 31 includes a transmission processing unit 311, a reception processing unit 312, and an antenna 313. Alternatively, the wireless communication unit 31 may regard at least one of the transmission processing unit 311, the reception processing unit 312, and the antenna 313 as the wireless communication unit 31. The wireless communication unit 31 may include a plurality of transmission processing units 311, a plurality of reception processing units 312, and a plurality of antennas 313. When the wireless communication unit 31 is adapted to a plurality of radio access schemes, each unit of the wireless communication unit 31 may be configured individually for each radio access scheme. The transmission processing unit 311 and the reception processing unit 312 may be individually configured by the LTE, the NR, the B5G, and the 6G. The antenna 313 may include a plurality of antenna elements, for example, a plurality of patch antennas. The wireless communication unit 31 may have a beamforming function. For example, the wireless communication unit 31 may have a polarization beamforming function using vertically polarized waves (V-polarized waves) and horizontally polarized waves (H-polarized waves) (or a polarization beamforming function using dual polarized waves in polarization directions of 45 degrees and -45 degrees from the vertical direction). Note that the wireless communication unit 31 may transmit a sensing signal explained above or below.

[0123] The transmission processing unit 311 performs transmission processing for downlink control information and downlink data. For example, the transmission processing unit 311 encodes, using an encoding scheme such as block encoding, convolutional encoding, or turbo encoding, downlink control information and downlink data input from the control unit 33. Here, as the encoding, encoding by a polar code or encoding by an LDPC code may be performed. Then, the transmission processing unit 311 modulates encoded bits with a predetermined modulation scheme (for example, BPSK, QPSK, 16QAM, 64QAM, 256QAM, or a higher order multi-value modulation scheme). In this case, signal points on a constellation do not always need to be equidistant. The constellation may be a non-uniform constellation. Then, the transmission processing unit 311 multiplexes modulation symbols and downlink reference signals of channels and arranges the modulation symbols and the downlink reference signals in a predetermined resource element. Then, the transmission processing unit 311 performs various kinds of signal processing on the multiplexed signals. For example, the transmission processing unit 311 performs processing such as conversion into a frequency domain by fast Fourier transform, addition of a guard interval (a cyclic prefix), generation of a baseband digital signal, conversion into an analog signal, quadrature modulation, up-conversion, removal of an extra frequency component, and amplification of electric power. A signal generated by the transmission processing unit 311 is transmitted from the antenna 313.

[0124] The reception processing unit 312 processes an uplink signal received via the antenna 313. For example, the reception processing unit 312 performs, on the uplink signal, down-conversion, removal of an unnecessary frequency component, control of an amplification level, quadrature demodulation, conversion into a digital signal, removal of a guard interval (a cyclic prefix), extraction of a frequency domain signal by fast Fourier transform, and the like. Then, the reception processing unit 312 separates uplink channels such as a PUSCH and a PUCCH and an uplink reference signal from the signal subjected to these processes. The reception processing unit 312 demodulates a reception signal for a modulation symbol of the uplink channel using a modulation scheme such as BPSK or QPSK. The modulation scheme used for the demodulation may be 16QAM, 64QAM, or 256QAM. In this case, signal points on a constellation do not always need to be equidistant. The constellation may be a non-uniform constellation (NUC). Then, the reception processing unit 312 performs decoding processing on encoded bits of the demodulated uplink channel. Decoded uplink data and uplink control information are output to the control unit 33.

[0125] The antenna 313 is an antenna device that mutually converts an electric current and a radio wave. The antenna 313 may include one antenna element, for example, one patch antenna. The antenna 313 may include a plurality of antenna elements, for example, a plurality of patch antennas. When the antenna 313 includes a plurality of antenna elements, the wireless communication unit 31 may have a beamforming function. The wireless communication unit 31 may be configured to generate a directional beam by controlling the directivity of a wireless signal using the plurality of antenna elements. The antenna 313 may be a dual-polarized antenna. When the antenna 313 is the dual-polarized antenna, the wireless communication unit 31 may use vertically polarized waves (V-polarized waves) and horizontally polarized waves (H-polarized waves) (or dual polarized waves in polarization directions of 45 degrees and -45 degrees from the vertical direction) when transmitting a wireless signal. The wireless communication unit 31 may control the directivity of the wireless signal transmitted using the vertically polarized waves and the horizontally polarized waves (or the dual polarized waves in the polarization directions of 45 Degrees and -45 Degrees from the vertical direction). The wireless communication unit 31 may transmit and receive spatially multiplexed signals via a plurality of layers including a plurality of antenna elements.

[0126] The storage unit 32 is a readable / writable storage device such as a DRAM, an SRAM, a flash memory, or a hard disk.

[0127] The control unit 33 is a control unit that controls the units of the relay station 30. The control unit 33 controls the wireless communication unit to carry out wireless communication with another wireless communication device (for example, the base station 20, the terminal device 40, or another relay station 30). The control unit 33 may be implemented by a processor such as a CPU or an MPU. Specifically, the control unit 33 may be implemented by the processor executing, using a RAM or the like as a work area, various programs stored in a storage device on the inside of the relay station 30. The control unit 33 may be implemented by an integrated circuit such as an ASIC or an FPGA. The control unit 33 may be implemented by a GPU. All of the CPU, the MPU, the ASIC, the FPGA, and the GPU can be regarded as a control unit. Note that the control unit 33 may include a plurality of physically separated objects. For example, the control unit 33 may include a plurality of semiconductor chips.

[0128] The control unit 33 includes at least one block of an acquisition unit 331, a transmission control unit 332, a reception control unit 333, and a communication control unit 334. The control unit 33 may include a plurality of each of these blocks or may include only one each of these blocks.

[0129] The blocks (the acquisition unit 331 to the communication control unit 334) configuring the control unit 33 are respectively functional blocks indicating functions of the control unit 33. These functional blocks may be software blocks or may be hardware blocks. For example, each of the functional blocks explained above may be one software module implemented by software (including a microprogram) or may be one circuit block on a semiconductor chip (a die). Naturally, each of the functional blocks may be one processor or one integrated circuit. The control unit 33 may be configured in functional units different from the functional blocks explained above. A configuration method for the functional blocks is optional. Note that an operation of the control unit 33 may be the same as the operation of the control unit (the control unit 13, the control unit 23, or the control unit 43) of the management device 10, the relay station 30, or the terminal device 40.

[0130] Note that the relay station 30 may be an IAB relay node. The relay station 30 operates as an IAB-MT (Mobile Termination) for an IAB donor node that provides backhaul and operates as an IAB-DU (Distributed Unit) for a terminal device 40 that provides access. The IAB donor node may be, for example, the base station 20. At this time, the IAB donor node may operate as an IAB-CU (Central Unit).

[0131] <2-4. Configuration example of the terminal device> Subsequently, a configuration example of the terminal device 40 is explained.

[0132] The terminal device 40 is a wireless communication device that performs wireless communication with another wireless communication device (for example, the base station 20, the relay station 30, or another terminal device 40). In the following explanation, the terminal device 40 is sometimes called UE (User Equipment) or UE40.

[0133] As the terminal device 40, all forms of information processing devices (computers) can be adopted. For example, the terminal device 40 may be a mobile terminal such as a mobile phone, a smart device (a smartphone or a tablet device), a PDA (Personal Digital Assistant), or a notebook PC. The terminal device 40 may be a communication module that is connected to an information processing device (for example, an imaging device not having a wireless communication function) and provides a wireless communication function to the information processing device. The terminal device 40 may be an imaging device (for example, a camcorder) having a wireless communication function.

[0134] The terminal device 40 may be a motorcycle, a mobile relay vehicle, or the like on which communication equipment such as an FPU (Field Pickup Unit) is mounted. The terminal device 40 may be an M2M (Machine to Machine) device or an IoT (Internet of Things) device. The terminal device 40 may be a wearable device such as a smartwatch.

[0135] The terminal device 40 may be an XR (Extended Reality) device such as an AR (Augmented Reality) device, a VR (Virtual Reality) device, or an MR (Mixed Reality) device. At this time, the XR device may be a glasses-type device such as AR glasses or MR glasses or may be a head-mounted device such as a VR head-mounted display. When the terminal device 40 is the XR device, the terminal device 40 may be a standalone device including only a user wearing portion (for example, an eyeglasses portion). The terminal device 40 may be a terminal interlocked device including a user wearing portion (for example, an eyeglasses portion) and a terminal portion (for example, a smart device) interlocked with the portion.

[0136] The terminal device 40 may be capable of performing NOMA communication with another wireless communication device (for example, the base station 20, the relay station 30, or another terminal device 40). The terminal device 40 may be capable of using an automatic retransmission technology such as HARQ when communicating with the other wireless communication device. The terminal device 40 may be capable of performing sidelink communication with the other terminal device 40. The terminal device 40 may be capable of using an automatic retransmission technology such as HARQ when performing the sidelink communication. The terminal device 40 may be capable of performing NOMA communication when performing the sidelink communication with the other terminal device 40. The terminal device 40 may be capable of performing LPWA communication with other wireless communication devices. Wireless communication used by the terminal device 40 may be wireless communication using millimeter waves. The wireless communication used by the terminal device 40 may be wireless communication using a radio wave including sidelink communication or may be wireless communication using an infrared ray or visible light, that is, optical radio.

[0137] The terminal device 40 may be a movable wireless communication device, that is, a mobile device. The terminal device 40 may be a wireless communication device installed in a mobile body or may be the mobile body itself. The terminal device 40 may be a vehicle that moves on a road, such as an automobile, a bus, a truck, or a motorcycle, or a car of a train that travels on a track, or may be a wireless communication device mounted on the vehicle. The mobile body may be a mobile terminal or may be a mobile body that moves on the land (on the ground in a narrow sense), in the ground, on the water, or under the water. The mobile body may be a mobile body that moves within the atmosphere, such as an aircraft, an airship, a balloon, or a helicopter or may be a mobile body that moves outside the atmosphere, such as an artificial satellite. The mobile body may be a UAV (Unmanned Aerial Vehicle) such as a drone. The terminal device 40 may be a wireless communication device mounted on the mobile body.

[0138] The terminal device 40 may be connected to and capable of communicating with a plurality of base stations 20 or a plurality of cells at the same time. When one base station 20 supports a communication area via a plurality of cells (for example, pCells or sCells), the plurality of cells can be bundled to communicate between the base station 20 and the terminal device 40 with a carrier aggregation (CA) technology, a dual connectivity (DC) technology, a multi-connectivity (MC) technology, or the like. Alternatively, the terminal device 40 and the plurality of base stations 20 may communicate with a coordinated transmission and reception (CoMP) technology via cells of different base stations 20.

[0139] The terminal device 40 may be connected to and capable of communicating with a plurality of base stations 20 or a plurality of cells. The terminal device 40 may transmit and / or receive sensing signals to and from each of the plurality of base stations 20. The terminal device 40 may be configured to receive information concerning sensing signals (for example, information concerning resources) from at least one of the plurality of base stations 20 or may be configured to receive information concerning sensing signals (for example, information concerning resources) from each of the plurality of base stations 20. The terminal device 40 may transmit and / or receive the sensing signals in each of the plurality of cells. The terminal device 40 may be configured to receive information concerning sensing signals (for example, information concerning resources) from at least one of the plurality of cells or may be configured to receive information concerning sensing signals (for example, information concerning resources) in each of the plurality of cells.

[0140] The terminal device 40 may be a relay terminal that relays communication to a remote terminal.

[0141] Multi-static sensing may be carried out in the base station 20, the remote terminal, and the relay terminal. Specifically, sensing signals may be transmitted from each of the base station 20 and the relay terminal. The remote terminal may receive the sensing signals transmitted from each of the base station 20 and the relay terminal.

[0142] The base station 20 and / or the relay terminal may transmit, to the relay terminal and / or the remote terminal, information concerning sensing signals transmitted and / or received by the relay terminal and / or the remote terminal. In other words, the relay terminal and / or the remote terminal may receive, from the base station 20 and / or the relay terminal, the information concerning the sensing signals transmitted and / or received by the relay terminal and / or the remote terminal.

[0143] Fig. 9 is a diagram illustrating a configuration of the terminal device 40 according to the present embodiment. The terminal device 40 includes a wireless communication unit 41, a storage unit 42, a control unit 43, and a sensor unit 44. The configuration illustrated in Fig. 9 is a functional configuration. A hardware configuration may be different from the configuration. The functions of the terminal device 40 may be distributed and implemented in a plurality of physically separated components.

[0144] Note that the terminal device 40 does not always need to include all of the components explained above or below. The terminal device 40 may include components other than the components explained above or below. The terminal device 40 may have a beamforming function. The terminal device 40 may be configured to acquire sensing data by performing sensing using a beam.

[0145] The wireless communication unit 41 is a signal processing unit for wirelessly communicating with another wireless communication device (for example, the base station 20, the relay station 30, or another terminal device 40). The wireless communication unit 41 may be referred to as wireless transceiver or simply referred to as transceiver. At this time, the wireless communication unit 41 may be a transceiver (hereinafter referred to as 3GPP transceiver) of a standard defined in the technical specifications of 3GPP. The 3GPP transceiver may be a 3G transceiver, may be a 4G (LTE) transceiver, may be a 5G (NR) transceiver, or may be a 5G or later generation transceiver. The wireless communication unit 41 is controlled by, for example, the control unit 43. The wireless communication unit 41 is adapted to one or a plurality of radio access schemes. The wireless communication unit 41 may be adapted to at least one of the NR, the LTE, the B5G, and the 6G. The wireless communication unit 41 may be adapted to the W-CDMA, the cdma2000, and the like in addition to the NR, the LTE, the B5G, and the 6G. The wireless communication unit 41 may be adapted to an automatic retransmission technology such as HARQ. A part or all of the kinds of processing executed by the wireless communication unit 41 may be executed by the control unit 43.

[0146] The wireless communication unit 41 includes a transmission processing unit 411, a reception processing unit 412, and an antenna 413. At least one of the transmission processing unit 411, the reception processing unit 412, and the antenna 413 may be regarded as the wireless communication unit 41. The wireless communication unit 41 may include a plurality of transmission processing units 411, a plurality of reception processing units 412, and a plurality of antennas 413. When the wireless communication unit 41 is adapted to a plurality of radio access schemes, the units of the wireless communication unit 41 may be configured individually for each of the radio access schemes. The transmission processing unit 411 and the reception processing unit 412 may be individually configured by the LTE, the NR, the B5G, and the 6G. The antenna 413 may include a plurality of antenna elements, for example, a plurality of patch antennas. The wireless communication unit 41 may have a beamforming function. For example, the wireless communication unit 41 may have a polarization beamforming function using vertically polarized waves (V-polarized waves) and horizontally polarized waves (H-polarized waves) (or a polarization beamforming function using dual polarized waves in polarization directions of 45 degrees and -45 degrees from the vertical direction). Note that the wireless communication unit 41 may transmit the sensing signals explained above or below.

[0147] The storage unit 42 is a readable / writable storage device such as a DRAM, an SRAM, a flash memory, or a hard disk.

[0148] The control unit 43 is a control unit that controls the units of the terminal device 40. The control unit 43 controls the wireless communication unit to carry out wireless communication with another wireless communication device (for example, the base station 20, the relay station 30, or another terminal device 40). The control unit 43 may be implemented by a processor such as a CPU or an MPU. Specifically, the control unit 23 may be implemented by the processor executing, using a RAM or the like as a work area, various programs stored in a storage device on the inside of the terminal device 40. The control unit 43 may be implemented by an integrated circuit such as an ASIC or an FPGA. All of the CPU, the MPU, the ASIC, and the FPGA can be regarded as a control unit. The control unit 43 may be implemented by a GPU. All of the CPU, the MPU, the ASIC, the FPGA, and the GPU can be regarded as a control unit. Note that the control unit 43 may include a plurality of physically separated objects. For example, the control unit 43 may include a plurality of semiconductor chips.

[0149] The control unit 43 includes at least one block of an acquisition unit 431, a transmission control unit 432, a reception control unit 433, and a communication control unit 434. The control unit 43 may include a plurality of each of these blocks or may include only one each of these blocks.

[0150] The blocks (the acquisition unit 431 to the communication control unit 434) configuring the control unit 43 are respectively functional blocks indicating functions of the control unit 43. These functional blocks may be software blocks or may be hardware blocks. For example, each of the functional blocks explained above may be one software module implemented by software (including a microprogram) or may be one circuit block on a semiconductor chip (a die). Naturally, each of the functional blocks may be one processor or one integrated circuit. The control unit 43 may be configured in functional units different from the functional blocks explained above. A configuration method for the functional blocks is optional. Note that an operation of the control unit 43 may be the same as the operation of the control unit (the control unit 13, the control unit 23, or the control unit 33) of the management device 10, the base station 20, or the relay station 30.

[0151] The sensor unit 44 is a sensor that acquires various kinds of information concerning wireless communication. For example, the sensor unit 44 is a sensor that acquires information concerning an object around the device. For example, the sensor unit 44 is a sensor that acquires information such as a location, a shape, and a motion of another object. Note that the sensor unit 44 is not limited to the sensor that acquires information concerning an object around the device. The sensor unit 44 may be a sensor for detecting a state of the device itself (for example, a location, moving speed, inclination, vibration, rotation, or temperature of the terminal device 40).

[0152] The sensor unit 44 may be an RF sensor (Radio Frequency Sensor) or may be a non-RF sensor. The sensor unit 44 may be a sensor system (for example, a sensor unit or a sensor module) in which the RF sensor and the non-RF sensor are combined.

[0153] Here, the RF sensor represents a component to be measured using a radio wave. Examples of the RF sensor include a radar using a radio wave such as a millimeter wave. At this time, the radio wave used for the radar is not limited to a radio wave in a millimeter wave band (for example, 30 to 300 GHz band) and may be, for example, a radio wave in a microwave band (for example, 3 to 30 GHz band) or a quasi-millimeter wave band (for example, 20 to 30 GHz band).

[0154] Other examples of the RF sensor include a wireless location positioning sensor (a wireless location positioning system). Examples of the wireless location positioning sensor include a GNSS (Global Navigation Satellite System)sensor. Here, the GNSS sensor may be a GPS (Global Positioning System) sensor, may be a GLONASS sensor, may be a Galileo sensor, or may be a QZSS (Quasi-Zenith Satellite System) sensor. Note that the wireless location positioning sensor is not limited to the GNSS sensor. Examples of the wireless location positioning sensor include a sensor for 3GPP positioning or Wi-Fi / Bluetooth positioning.

[0155] The non-RF sensor represents a component to be measured without using a radio wave. Examples of the non-RF sensor include a distance measuring sensor (a distance measuring system) such as a LiDAR (Light Detection And Ranging). At this time, light (for example, laser light) used by the distance measuring sensor is not limited to visible light and may be invisible light such as an ultraviolet ray, an infrared ray, or a near infrared ray. Other examples of the non-RF sensor include a sonar using a sound wave such as an ultrasonic wave.

[0156] Other examples of the non-RF sensor include a camera. Note that the camera is not limited to a visible light camera. For example, the camera may be a near-infrared camera, a mid-infrared camera, or a far-infrared camera. The camera may be a monocular camera or a stereo camera. Other examples of the non-RF sensor may include an image sensor. At this time, in the image sensor, image plane phase difference pixels may be discretely embedded. Besides, the sensor unit 44 may be a ToF (Time of Flight) sensor or may be a microphone.

[0157] Other examples of the non-RF sensor include an acceleration sensor (for example, a triaxial acceleration sensor), a speed sensor, a gyro sensor, an IMU(Inertial Measurement Unit), and another motion sensor. Other examples of the non-RF sensor include a magnetic sensor, an aerotonometer, and an altimeter (for example, a barometer).

[0158] The sensor unit 44 may be a sensor that acquires various kinds of information for predicting the quality of a communication path. For example, the sensor unit 44 may be a sensor that detects reception S / N of a radio wave received from another communication device (for example, a communication device to be a communication partner or a communication device other than the communication partner). Naturally, the information acquired by the sensor unit 44 is not limited to the reception S / N if the information can be used for the quality prediction for the communication path.

[0159] Naturally, the sensor unit 44 is not limited to the sensors explained above. The sensor unit 44 may be a sensor system obtained by combining a plurality of the sensors explained above.

[0160] <<3. Communication point>> The configuration of the communication system 1 is explained above. A communication point is explained before the operation of the communication system 1 in the present embodiment is explained in detail.

[0161] In the communication system of the related art, communication control (for example, initial access control and / or mobility control) is performed in units of cells. That is, the cell of the related art can be defined as a unit of a transmission and reception point (a communication node) for communication control.

[0162] However, from now on, in addition to a communication topology becoming complicated, it is assumed that a high-frequency band such as a millimeter wave or a terahertz wave is utilized. For that reason, in future communication systems, it is necessary to increase the density of a unit of communication control. In the present embodiment, the unit of communication control is not referred to as cell but is referred to as communication point.

[0163] In the present embodiment, a cell-free communication system is assumed as an example of a communication system using a communication point. However, the point in the present embodiment is not a change of the definition of a cell. A method in the present embodiment can be applied to a communication system in which the definition of a cell is not changed from the definition of a cell of the related art. That is, one of communication systems to which the method in the present embodiment can be applied is the cell-free communication system. The method in the present embodiment is also applicable to a communication system other than the cell-free communication system. For example, the method in the present embodiment is also applicable to a distributed MIMO system, a distributed antenna system, a multi-TRP (Transmission and Reception Point) system, or a multi-AP (Access Point) system.

[0164] <3-1. Definition of the communication point> The communication point is, for example, one radio resource at the time when a communication service is provided. The communication point may be called communication node or node.

[0165] The communication point may be a cell of the related art (a planar cell of the related art formed by the base station 20 / the relay station 30. Hereinafter referred to as classic cell). However, the communication point is not limited to the cell and may be, for example, a beam in beamforming (hereinafter also referred to as beam cell) or may be a point in point forming (hereinafter also referred to as point cell). The point forming is explained below.

[0166] Besides, the communication point may be a radio resource divided spatially, temporally, or in terms of frequency. A plurality of radio resources multiplexed spatially, temporally, or in terms of frequency may be the communication point. The wireless communication device (for example, at least one of the base station 20, the relay station 30, and the terminal device 40) is capable of identifying respective communication points with some means.

[0167] The communication point in the present embodiment may be any of the following (A1) to (A15). The description of "communication point" appearing in the present embodiment can be replaced with a description indicating any of (A1) to (A15) below.

[0168] (A1) Cell (Classic cell) (A2) Base station (for example, gNB) (A3) Relay station (A4) TRP (Transmission Reception Point) (A5) Antenna (A6) Antenna element (A7) Antenna port (A8) Set of antenna ports (A9) IAB (Integrated Access and Backhaul) node (A10) Relay UE (User Equipment) (A11) Beam in beamforming (Beam cell) (A12) Point in point forming (Point cell) (A13) CU(Central Unit) (A14) DU(Distributed Unit) (A15) RU(Radio Unit)

[0169] The communication point in the present embodiment may be a cluster configured by combining a plurality of elements selected out of the (A1) to (A15) described above. The description of "communication point" appearing in the present embodiment can also be replaced with a description indicating this cluster.

[0170] The communication point in the present embodiment can also be defined as (B1) to (B2) below in addition to or instead of the above.

[0171] (B1) Node that transmits synchronization signal and / or report control information For example, the communication point may be a unit (a node) that the terminal device 40 can recognize as a transmission destination of a synchronization signal and / or report control information (for example, SSB / SIB1).

[0172] (B2) Unit defined based on a QCL (Quasi-co-location) For example, a set of antenna ports that are the same QCL may be recognized as one communication point (cluster). The communication point may be defined or recognized in a TCI state. For example, a TRP, an antenna, or an antenna element defined or recognized by one TCI state can be defined as one communication point.

[0173] In addition, the communication point in the present embodiment does not need to be fixed and may be a moving node. Furthermore, the communication point in the present embodiment does not need to be a node present on the ground (terrestrial) and may be a node present on a non-ground (non-terrestrial). For example, the communication point in the present embodiment may be a satellite, a drone, or a UAV (Unmanned Aerial Vehicle).

[0174] As explained above, the base station 20 may be defined as a communication point. However, in the present embodiment, the base station 20 may not always be a communication point. For example, a base station 20 (or the function of the base station 20 in the present embodiment) may be a communication node that can control a communication point connecting to the base station 20. For example, the base station 20 in the present embodiment may be a node further on the core network CN side than the communication point.

[0175] Note that the base station 20 can be implemented in various forms from a viewpoint of a device. For example, the base station 20 may be included in a plurality of communication points. The base station 20 may control other communication points. For example, the base station 20 may be independent as a communication node between the core network CN and the communication point. For example, the base station 20 may be included in the core network CN.

[0176] The communication point in the present embodiment may be a cluster by clustering. The definitions of the clustering and the cluster are, for example, as follows.

[0177] (Clustering) The clustering refers to, for example, setting simultaneously connected one or more communication nodes (or candidates of one or more communication nodes). Information concerning a QCL can be set for each of communication nodes to be clustered. For example, it is assumed that the communication node is an antenna port and a plurality of communication nodes (that is, antenna ports) are set in one cluster. In this case, it indicates that, in the cluster, communication nodes of the same TRP are the same QCL and indicated that communication nodes of different TRPs are different QCLs. In other words, in one cluster, communication nodes of the same QCL and different QCLs can be set in a mixed manner.

[0178] (Cluster) The cluster refers to, for example, a set (a list) of clustered communication nodes. As an example, the cluster may be a set of communication nodes configured by RRC signaling. As another example, the cluster may be a set of communication nodes set by the RRC signaling and may be a candidate for a communication node that actually communicates. Note that the communication node that actually communicates can be defined as a sub-cluster.

[0179] Note that the cluster can be called in another name. Alternatively, the cluster can be defined by another definition. For example, the cluster may be called / defined as indicated by at least one of (C1) to (C6) below.

[0180] (C1) Node set The cluster may be called node set.

[0181] (C2) Zone (area) A zone is a spatial area that can be defined according to a physical location, a virtual location, or the like. A given zone can include a plurality of communication nodes. The zone can also be simply called area.

[0182] (C3) Cell set (cell) In particular, when the communication node is a cell (a classic cell), the cluster in the present embodiment may be called cell set. The cell set can also be simply called cell.

[0183] (C4) Antenna port set In particular, when the communications node is an antenna port, the cluster in the present embodiment can be called antenna port set.

[0184] (C5) Beam set In particular, when the communication node is a beam (a beam cell), the cluster in the present embodiment can be called beam set.

[0185] (C6) Point set In particular, when the communication node is a point (a point cell), the cluster in the present embodiment can be called point set.

[0186] Note that a specific identifier (cluster ID) may be given to each cluster.

[0187] In addition, a plurality of clusters may be set. In this case, the set plurality of clusters may be called cluster set (cluster list). Note that a node included in a certain cluster may be included in another cluster. That is, one node can be included in a plurality of clusters.

[0188] The clusters can be dynamically or quasi-statically switched and used.

[0189] <3-2. Specific example of the communication system> Subsequently, a specific example of the communication system using the communication point is explained. As explained above, in the present embodiment, the cell-free communication system is assumed as an example of the communication system using the communication point. However, the communication system 1 in the present embodiment is not limited to the cell-free communication system.

[0190] Fig. 10 is a diagram illustrating an example of the communication system 1 in the present embodiment. The communication system 1 in the present embodiment is a wireless communication system including a plurality of communication devices (for example, one or a plurality of terminal devices 40 and one or a plurality of base stations 20). Note that, in the following explanation, the base station 20 is sometimes referred to as BS. In the following explanation, the terminal device 40 is sometimes referred to as UE.

[0191] The base station 20 includes one or a plurality of communication points P (for example, one or a plurality of communication antennas). Alternatively, the base station 20 is connected to the one or plurality of communication points P (for example, one or a plurality of other base stations 20 and / or one or a plurality of relay stations 30) by wire or radio. Note that the communication point P may be a part of components included in the base station 20. For example, the one or plurality of communication points P may be one or a plurality of antennas included in the base station 20.

[0192] In the example illustrated in Fig. 10, the base station 201(BS1illustrated in Fig. 10) is connected to communication points P11to P1N. Alternatively, the base station 201(BS1illustrated in Fig. 10) includes the communication points P11to P1N. Here, N is any integer. In the example illustrated in Fig. 10, the base station 202(BS2illustrated in Fig. 10) is connected to communication points P21to P2M. Alternatively, the base station 202(BS2illustrated in Fig. 10) includes communication points P21to P2M. Here, M is any integer.

[0193] The communication points may be controlled by the connected base station 20. For example, the communication points P11to P1Nmay be controlled by the base station 201. The communication points P21to P2Mmay be controlled by the base station 202.

[0194] The terminal device 40 (UE illustrated in Fig. 10) is wirelessly connected to one or more communication points P.

[0195] <3-3. Point forming> As explained above, the communication point may be a point in point forming. The point forming is a technology of concentrating electric power at a specific point using a phase difference of a near field. Hereinafter, a power concentration technology (the point forming) to the specific point is explained.

[0196] Fig. 11 is a diagram for explaining the power concentration technology (the point forming) for the specific point. In the cellular mobile communication of the related art, the base station 20(for example, an eNB (eNodeB), a gNB (gNodeB), or an RAN node (EUTRAN, NGRAN)) concentrates electric power in a planar or a beam shape to form a communicable region (including a femtocell, a small cell, and a large cell). In the example illustrated in Fig. 11, a diagram on the left side (a classic cell) is a diagram illustrating a state in which the base station 20 forms a planar cell. A diagram in the center (beamforming) is a diagram illustrating a state in which the base station 20 forms a beam-like cell. Accordingly, the base station 20 provides communication to the terminal device 40(for example, UE (User Equipment)). In cellular communication / cell-free communication in the next generation, in order to satisfy further advanced requests (for example, more simultaneous multiple connection (mMTC) and / or more highly reliable low latency communications (URLLC)), it is requested to increase utilization efficiency of radio resources (for example, at least one of a frequency, a space, and a time) to the limit.

[0197] In the beamforming, the communication device cooperatively controls a large number of antennas to increase a power value in a specific direction. Currently, as a next technology of the beamforming, a technology of forming cells as dots (a power concentration technology to a specific point) has attracted attention. This is a technology of coordinately controlling a large number of transmission devices (a transmission antenna or a device including one or more transmission antennas) to concentrate electric power at one point on three dimensions beyond spatial separation by the beamforming of the related art. In the example illustrated in Fig. 11, a diagram on the right side (point forming) is a diagram illustrating a state in which the base station forms dotted cells (hereinafter also referred to as point cells). Hereinafter, this technology is called point forming. However, a way of calling is not limited thereto. For example, point forming may be called Beamfocusing, Beamfocal, or the like.

[0198] In the beamforming of the related art, beam directions cannot be multiplexed. However, in the point forming, three-dimensional multiplexing can be performed. This enables simultaneous communication of more multiple terminals. Interference with multiple terminals can be suppressed by the point forming. As a result, improvement in communication quality of the entire system, a reduction in a communication disconnection rate, and more multiple connection communication can be expected.

[0199] The point forming is a technology of maximizing reception power at a specific point by, considering a phase difference of radio waves transmitted from a large number of transmission antennas, cooperatively operating the large number of transmission antennas such that radio waves are in-phase synthesized at the specific point. Since the radio waves transmitted from the large number of transmission antennas are received at random phases at points other than the specific point, reception power is suppressed by averaging. Accordingly, the point forming for forming a cell at the specific point is implemented. Here, in the phase difference control for the radio waves transmitted from the large number of transmission antennas, for example, the control device may control the initial phase of the transmission antennas or may control the amplitude of the transmission antennas.

[0200] The plurality of antennas (a plurality of transmission points) used for the point forming may be one or a plurality of transmission panels including a plurality of transmission antennas (antenna elements). Fig. 12 is a diagram illustrating an example of point forming with a single antenna including a large number of antenna elements. When a radio wave is transmitted from a single transmission panel including a large number of transmission antenna elements, characteristics of the near field may be considered.

[0201] Fig. 13 is a diagram for explaining a near field and a far field. In the related art, it has been assumed that a base station communicates with a remote terminal device such as a smartphone. For that reason, in the related art, studies have been conducted on the premise of the far field as illustrated on the right side of Fig. 13. However, in the future, communication using a huger transmission panel is assumed. For that reason, it is likely that communication considering a phase difference, which is a characteristic of a near field region, can be performed. The point forming may be used in this near field region. Fig. 14 is a diagram illustrating the Fraunhofer distance (also referred to as Rayleigh distance) that is a boundary between the near field and the far field.

[0202] Here, an example in which the point forming is applied in the near field is explained above. However, the point forming can be implemented in an environment in which a phase difference can be considered. For that reason, in an environment in which a large number of distributed antennas are present around a reception point, it is possible to carry out the point forming regardless of the Fraunhofer distance. Naturally, if the phase difference can be considered at a power concentration point, the communication device can also carry out the point forming using a single antenna including a large number of antenna elements.

[0203] Fig. 15 is a diagram illustrating an example of point forming in a distributed antenna environment. In the example illustrated in Fig. 15, the base station 20 includes a control unit (in the example illustrated in Fig. 15, a CU (Central Unit)), which controls a plurality of antennas, and controls a transmission antennas. In the example illustrated in Fig. 15, one CU controls the transmit antenna. However, control does not need to be the control by one CU. A plurality of elements (for example, a DU (Distributed Unit), an RAT (Radio Access Technology), and a TRP (Transmission Reception Point) may cooperatively operate. In the example illustrated in Fig. 15, the CU and the transmission antenna are optically connected. However, connection may not always be the optical connection. Note that each of a plurality of transmission points (transmission antennas) may be one base station 20. One or a plurality of base stations 20 may control the plurality of transmission points (transmission antennas).

[0204] In general, a degree of the power concentration point of the point forming fluctuates depending on the number of transmission points used at the time of power concentration. The number of transmission points used to form one or more reception points and detailed power control have a positive correlation. That is, as the number of transmission points increases, more detailed power control is possible.

[0205] Note that wireless communication relating to the point forming is not limited to wireless communication using the technology of concentrating electric power at a specific point using a phase difference of a near field (the power concentration technology). The wireless communication relating to the point forming may be near field communication. Here, the near field communication may be communication at a distance, determined from a frequency band and an opening length of a transmission panel, shorter than the Fraunhofer distance.

[0206] In the example explained above, one base station 20 executes the processing relating to the point forming. However, a plurality of base stations 20 may cooperate to execute the processing relating to the point forming. For example, the plurality of base stations 20 may form a point cell by cooperatively controlling the respective transmission antennas with other base stations 20. The base station 20 may perform cooperative control with the relay station 30.

[0207] <<4. Initial access control>> The communication point is explained above. Initial access control (also referred to as initial access procedure, initial access method, initial access processing, or initial connection processing) is explained before an operation of the communication system 1 in the present embodiment is explained in detail.

[0208] <4-1. Basic procedure> First, as a basic procedure of the initial access control, an example of a connection procedure of the terminal device 40 to the base station 20 is explained. Note that the description of "base station 20" and / or "cell" appearing in the following explanation can be replaced with "communication point".

[0209] The initial access control is processing for transitioning a wireless connection state of the terminal device 40 from an unconnected state to the connected state. In the following explanation, the initial access control is sometimes referred to as an initial access procedure or initial access processing.

[0210] Here, the unconnected state refers to, for example, RRC_IDLE and / or RRC_INACTIVE. The RRC_IDLE refers to an idle state in which the terminal device 40 is not connected to any cell and is also called Idle mode. In addition, the RRC_INACTIVE is a wireless connection state indicating an inactive state specified by the NR anew and is also called Inactive mode. In the RRC_INACTIVE, RRC connection itself is not established between the terminal device 40 and the base station 20. However, the terminal device 40 and the base station 20 may keep a state of holding some UE contexts each other. The terminal device 40 and the base station 20 may use the held UE context in order to speed up the transition of the terminal device 40 to the connected state again. Note that the unconnected state may include the Lightning mode. The connection state is, for example, RRC_CONNECTED. The RRC_CONNECTED is a connection state in which the terminal device 40 is connected to a specific cell (for example, a Primary Cell) and is also called CONNECTED mode.

[0211] Fig. 16 is a sequence diagram illustrating an example of the initial access processing. Hereinafter, the initial access processing is explained with reference to Fig. 16.

[0212] The terminal device 40 in the unconnected state performs a cell selection procedure (a cell search). The cell selection procedure (the cell search) is a procedure for a UE (User Equipment) for detecting a PCI of a cell (Physical Cell ID) and obtaining time and frequency synchronization. The cell search in the present embodiment includes steps of detecting a synchronization signal and decoding a PBCH (Physical Broadcast Channel). First, the base station 20 transmits an SSB (SS / PBCH block) and / or a PBCH (Physical Broadcast Channel) (step S11). The SSB is a block (a signal / information / channel) including the PBCH, a PSS (Primary Synchronization Signal), and an SSS(Secondary Synchronization Signal). The terminal device 40 detects a synchronization signal (SS) of the cell (step S12).

[0213] The terminal device 40 performs synchronization in a downlink with the cell based on the detected synchronization signal. Then, after the downlink synchronization is established, the terminal device 40 attempts to decode the PBCH and acquires an MIB (Master Information Block) that is a part of system information (step S13).

[0214] The system information is information for reporting a setting in a cell to which the system information is transmitted. The system information may be information common to all the terminal devices 40 belonging to the cell. The system information may be information specific to the cell. The system information includes, for example, information concerning access to the cell, information concerning cell selection, and information concerning other RATs and other systems. The system information includes an MIB (Master Information Block) and an SIB(System Information Block). The MIB is information necessary for receiving the SIB and the like and is information having a fixed payload size reported by the PBCH. The MIB includes a part of a system frame number, information concerning a subcarrier spacing of predetermined information (for example, SIB1, Msg.2 / Msg.4 for initial connection, paging, and broadcast SI message), information concerning a subcarrier offset, information concerning the location of a DMRS type A, PDCCH setting for at least an SIB1, information concerning cell connection prohibition (cell barred), and information concerning intra-frequency reselection. The SIB is system information other than the MIB and is reported by the PDSCH.

[0215] Note that 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 concerning access to a cell, information concerning acquisition of other system information, and information concerning cell selection. The information included in the MIB is first system information. The information included in the SIB1 in the SIB is second system information (for example, Remaining Minimum SI). The remaining system information is third system information (for example, Other SI).

[0216] In the NR as well, the system information is reported from the NR cell. A physical channel for carrying the system information may be transmitted in a slot or a mini-slot. The mini-slot is defined by the number of symbols smaller than the number of symbols of the slot. Since the physical channel for carrying the system information is transmitted in the mini-slot, time necessary for beam sweep is reduced and overhead can be reduced. In the case of the 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.

[0217] The terminal device 40 acquires the second system information based on the MIB (that is, the first system information) (step S14). As explained above, the second system information includes the SIB1 and an SIB2.

[0218] The SIB1 is scheduling information of access control information of a cell and system information other than the SIB1. In the case of the NR, the SIB1 includes information concerning cell selection (for example, cellSelectionInfo), information concerning cell access (for example, cellAccessRelatedInfo), information concerning connection establishment failure control (for example, connEstFailureControl), scheduling information (for example, si-SchedulingInfo) of system information other than the SIB1, and setting of a serving cell. The setting of the serving cell includes a cell-specific parameter and includes a downlink setting, an uplink setting, and TDD setting information. The uplink setting includes a RACH setting. In the case of the LTE, the SIB1 includes access information of a cell, cell selection information, maximum uplink transmission power information, TDD setting information, a period of system information, mapping information of system information, and the length of an SI (System Information) window.

[0219] In the case of the NR, the SIB2 includes cell reselection information (for example, cellReselectionInfoCommon) and cell reselection serving frequency information (for example, cellReselectionServingFreqInfo). In the case of the LTE, the SIB2 includes connection prohibition information, radio resource setting information (radioResourceConfigCommon) common to cells, and uplink carrier information. The radio resource setting information common to cells includes setting information of a PRACH (Physical Random Access Channel) and an RACH (Random Access Channel) common to cells.

[0220] When the terminal device 40 did not successfully acquire system information necessary for establishing a link, the terminal device 40 determines that access to a cell indicated by the system information is prohibited. For example, when the terminal device 40 did not successfully acquire the first system information, the terminal device 40 determines that access to a cell indicated by the first system information is prohibited. In this case, the terminal device 40 ends the initial access processing.

[0221] When the terminal device 40 successfully acquired system information, the terminal device 40 executes a random access procedure based on the first system information and / or the second system information (steps S15 to S18). The random access procedure is sometimes called RACH procedure (Random Access Channel Procedure) or a RA procedure.

[0222] The random access procedure includes a of transmitting a random access preamble (step S15), a step of receiving a random access response (step S16), a step of transmitting a message 3 (step S17), and a step of receiving contention resolution (step S17).

[0223] First, the terminal device 40 selects a predetermined PRACH (Physical Random Access Channel) preamble and transmits the predetermined PRACH preamble to the base station 20 (step S15). Subsequently, the terminal device 40 receives a PDSCH (Physical Downlink Shared Channel) including a random access response corresponding to the PRACH preamble (step S16). Subsequently, the terminal device 40 transmits a PUSCH including the message 3 using a resource scheduled by a random access response grant included in the random access response (step S17). Finally, the terminal device 40 receives the PDSCH including a contention resolution corresponding to the PUSCH (step S18).

[0224] The message 3 includes an RRC (Radio Resource Control) message of an RRC connection request. The contention resolution includes an RRC message for RRC connection setup. When receiving the RRC message of the RRC connection setup, the terminal device 40 performs an RRC connection operation and transitions from an RRC idle state to an RRC connected state. After transitioning to the RRC connected state, the terminal device 40 transmits an RRC message of RRC connection setup completion to the base station 20. Through the series of operations, the terminal device 40 can be connected to the base station 20.

[0225] Note that the random access preamble is sometimes called message 1, the random access response is sometimes called message 2, the contention resolution is sometimes called message 4, and the RRC connection setup completion message is sometimes called message 5.

[0226] After all the steps of the random access procedure are completed, the terminal device 40 can transition to a state of being connected to the cell (a connected state).

[0227] Note that the random access procedure illustrated in Fig. 16 is sometimes called four-step random access procedure (four-step RACH procedure). On the other hand, a random access procedure in which the terminal device 40 also transmits the message 3 according to the transmission of the random access preamble and the base station 20 transmits a random access response and contention resolution as a response to the messages is sometimes called two-step random access procedure (two-step RACH procedure).

[0228] <4-2. Random access procedure> Subsequently, the random access procedure is explained in detail.

[0229] The random access procedure is executed for the purpose of "RRC connection setup" from the idle state to the connected state (or the inactive state), "request for state transition" from the inactive state to the connected state, and the like. The random access procedure is also used for the purpose of "scheduling request" for performing a resource request for uplink data transmission and "timing advance adjustment" for adjusting uplink synchronization. Besides, the random access procedure is executed in the case of "on-demand SI request" for requesting system information that is not transmitted, "beam recovery" for recovering interrupted beam connection, "handover" for switching a connected cell, and the like.

[0230] The "RRC connection setup" is an operation executed when the terminal device 40 is connected to the base station 20 according to, for example, occurrence of traffic. Specifically, the "RRC connection setup" is an operation of passing information concerning connection (for example, UE context) from the base station 20 to the terminal device 40. The UE context is managed by predetermined communication device identification information (for example, C-RNTI) instructed from the base station 20. When ending this operation, the terminal device 40 transitions from the idle state to the inactive state or from the idle state to the connected state.

[0231] The "request for state transition" is an operation in which the terminal device 40 requests state transition from the inactive state to the connected state according to, for example, occurrence of traffic. By transitioning to the connected state, the terminal device 40 can transmit and receive unicast data to and from the base station 20.

[0232] The "scheduling request" is an operation in which the terminal device 40 performs a resource request for uplink data transmission according to, for example, occurrence of traffic. After normally receiving the scheduling request, the base station 20 assigns a resource of the PUSCH to the communication device. Note that the scheduling request is also performed by the PUCCH.

[0233] The "timing advance adjustment" is an operation for adjusting an error between downlink and uplink frames caused by a propagation delay. The terminal device 40 transmits a PRACH (Physical Random Access Channel) at timing adjusted to the downlink frame. Accordingly, the base station 20 can recognize the propagation delay between the base station 20 and the terminal device 40 and can indicate a value of timing advance to the terminal device 40 with the message 2 or the like.

[0234] The "on-demand SI request" is an operation of requesting the base station 20 to transmit system information when the terminal device 40 needs system information not transmitted for the purpose of, for example, overhead of the system information.

[0235] The "beam recovery" is an operation of requesting recovery when communication quality is deteriorated because of movement of the terminal device 40 or interruption of a communication path by another object after a beam is established. When receiving this request, the base station 20 attempts connection to the terminal device 40 using a different beam.

[0236] The "Handover" is an operation of switching connection from a connected cell (a serving cell) to a cell adjacent to a cell adjacent to the cell (a neighbor cell) because of, for example, a change in a radio wave environment such as movement of the terminal device 40. The terminal device 40 that has received the handover command from the base station 20 performs a connection request to the neighbor cell designated by the handover command.

[0237] The random access procedure includes a contention-based random access procedure and a non-contention-based random access procedure.

[0238] Note that the random access procedure explained below is a random access procedure in which it is assumed that an RAT supported by the communication system 1 is an LTE. However, the random access procedure explained below is also applicable to a case in which the RAT supported by the communication system 1 is other than LTE. For example, the random access procedure explained below is also applicable to a case in which the RAT supported by the communication system 1 is an RAT of the 5G, the B5G, the 6G, or a later generation.

[0239] Hereinafter, the contention-based random access procedure and the non-contention-based random access procedure is explained in detail.

[0240] <4-2-1. Contention-based random access procedure> The contention-based random access procedure is a random access procedure led by the terminal device 40. Fig. 17 is a diagram illustrating the contention-based random access procedure. As illustrated in Fig. 17, the contention-based random access procedure is a four-step procedure starting from transmission of a random access preamble from the terminal device 40. The contention-based random access procedure includes a step of transmitting a random access preamble (a Message 1), a step of receiving a random access response (a Message 2), a step of transmitting a message (a Message 3), and a step of receiving a message (a Message 4) for contention resolution.

[0241] First, the terminal device 40 randomly selects a preamble sequence to be used out of a predetermined plurality of preamble sequences. Then, the terminal device 40 transmits a message (the Message 1: the Random Access Preamble) including the selected preamble sequence to the base station 20 at a connection destination (step S21). The random access preamble is transmitted on the PRACH.

[0242] When receiving the random access preamble, the base station 20 transmits a random access response (the Message 2) to the random access preamble to the terminal device 40. This random access response is transmitted using, for example, the PDSCH. The terminal device 40 receives the random access response (the Message 2) transmitted from the base station 20 (step S22). The random access response includes one or a plurality of random access preambles successfully received by the base station 20 and a resource of a UL (Up Link) (hereinafter referred to as uplink grant) corresponding to the random access preamble. The random access response includes a TC-RNTI (Temporary Cell Radio Network Temporary Identifier) that is an identifier specific to the terminal device 40 temporarily assigned to the terminal device 40 by the base station 20.

[0243] When receiving the random access response from the base station 20, the terminal device 40 discriminates whether the random access preamble transmitted in step S21 is included in reception information. When the random access preamble is included, the terminal device 40 extracts an uplink grant corresponding to the random access preamble transmitted in step S21 out of uplink grants included in the random access response. Then, the terminal device 40 transmits a UL message (the Message 3: Scheduled Transmission) using a resource scheduled by the extracted uplink grant (step S23). The transmission of the message (the Message 3) is performed using the PUSCH. The message (the Message 3) includes an RRC message for an RRC (Radio Resource Control) connection request. The message (the Message 3) includes an identifier of the terminal device 40.

[0244] In the contention-based random access procedure, the random access preamble randomly selected by the terminal device 40 is used for the procedure. For that reason, it could occur that the terminal device 40 transmits the random access preamble and, at the same time, another terminal device 40 transmits the same random access preamble to the base station 20. Thus, by receiving the identifier transmitted by the terminal device 40 in step S23, the base station 20 recognizes between which terminal devices contention of preambles has occurred and resolves the contention The base station 20 transmits a contention resolution (the Message 4) to the terminal device 40 selected by the contention resolution. The contention resolution (the Message 4) includes the identifier transmitted by the terminal device 40 in step S23. The contention resolution (the Message 4) includes an RRC message of RRC connection setup. The terminal device 40 receives a contention resolution message (the Message 4) transmitted from the base station 20 (step S24).

[0245] The terminal device 40 compares the identifier transmitted in step S23 and the identifier received in step S24. When the identifiers do not coincide, the terminal device 40 performs the random access procedure again from step S21. When the identifiers coincide, the terminal device 40 performs an RRC connection operation and transitions from the idle state (RRC_IDLE) to the connected state (RRC_CONNECTED). The terminal device 40 uses the TC-RNTI acquired in step S22 in subsequent communication as a C-RNTI (Cell Radio Network Temporary Identifier). After transitioning to the connected state, the terminal device 40 transmits an RRC message of RRC connection setup completion to the base station 20. The RRC connection setup complete message is also referred to as message 5. Through the series of operations, the terminal device 40 is connected to the base station 20.

[0246] Note that the contention-based random access procedure illustrated in Fig. 17 is a four-step random access procedure (four-step RACH). However, the communication system 1 is also capable of supporting a two-step random access procedure (two-step RACH) as the contention-based random access procedure. For example, the terminal device 40 also transmits the message (the Message 3) indicated in step S23 together with the transmission of the random access preamble. Then, the base station 20 transmits a random access response (the Message 2) and a contention resolution (the Message 4) as a response to the messages. Since the random access procedure is completed in two steps, the terminal device 40 can be quickly connected to the base station 20.

[0247] Note that the message 1 is sometimes described as "Msg1" or "Msg. 1". The message 2 is sometimes described as "Msg2" or "Msg. 2". The message 3 is sometimes described as "Msg3" or "Msg. 3". The message 4 is sometimes described as "Msg4" or "Msg. 4".

[0248] <4-2-2. Non-contention-based random access procedure> The non-contention-based random access procedure is a random access led by the base station 20. Fig. 18 is a diagram illustrating the non-contention-based random access procedure. The non-contention-based random access procedure is a three-step procedure starting from transmission of a random access preamble assignment from the base station 20. The non-contention-based random access procedure includes a step of receiving a random access preamble assignment (a Message 0), a step of transmitting a random access preamble (a Message 1), and a step of receiving a random access response (a Message 2).

[0249] In the contention-based random access procedure, the terminal device 40 randomly selects the preamble sequence. However, in the non-contention-based random access procedure, the base station 20 assigns an individual random access preamble to the terminal device 40. The terminal device 40 receives the random access preamble assignment (the Message 0) from the base station 20 (step S31).

[0250] The terminal device 40 executes random access to the base station 20 using the random access preamble assigned in step S31. That is, the terminal device 40 transmits the assigned random access preamble (the Message 1) to the base station 20 on the PRACH (step S32).

[0251] The base station 20 receives the random access preamble (the Message 1) from the terminal device 40. Then, the base station 20 transmits, to the terminal device 40, a random access response (the Message 2) to the random access preamble (step S33). The random access response includes, for example, information concerning an uplink grant corresponding to the received random access preamble. When receiving the random access response (the Message 2), the terminal device 40 performs an RRC connection operation and transitions from the idle state (RRC_IDLE) to the connected state (RRC_CONNECTED).

[0252] As explained above, in the non-contention-based random access procedure, since the base station 20 schedules the random access preamble, contention of preambles less easily occurs.

[0253] Note that the message 0 is sometimes described as "Msg0" or "Msg.0". The message 1 is sometimes described as "Msg1" or "Msg. 1". The message 2 is sometimes described as "Msg2" or "Msg. 2".

[0254] <4-2-3. Details of an NR random access procedure> The random access procedure in which it is assumed that the RAT supported by the communication system 1 is the LTE is explained above. Note that the random access procedure explained above can also be applied to an RAT other than the LTE. Hereinafter, a random access procedure in which it is assumed that the RAT supported by the communication system 1 is an NR (5G) is explained in detail.

[0255] Note that, in the following explanation, four steps concerning the Message 1 to the Message 4 illustrated in Fig. 17 or Fig. 18 are respectively explained in detail. The step of the Message 1 corresponds to step S21 illustrated in Fig. 17 or step S32 illustrated in Fig. 18. The step of the Message 2 corresponds to step S22 illustrated in Fig. 17 or step S33 illustrated in Fig. 18. The step of the Message 3 corresponds to step S23 illustrated in Fig. 17. The step of the Message 4 corresponds to step S24 illustrated in Fig. 17.

[0256] NR random access preamble (the Message 1) In the NR, the PRACH is called NR-PRACH (NR Physical Random Access Channel). The NR-PRACH is configured using a Zadoff-Chu sequence. In the NR, a plurality of preamble formats are specified as a format of the NR-PRACH. The preamble format is specified by a combination of parameters such as a subcarrier spacing, a transmission bandwidth, a sequence length, the number of symbols used for transmission, the number of transmission repetitions, a CP (Cyclic Prefix) length, and a guard period length of the PRACH. A type of a preamble sequence of the NR-PRACH is numbered. The number of the type of the preamble sequence is called preamble index.

[0257] In the NR, setting concerning the NR-PRACH is performed on the terminal device 40 in the idle state according to system information. Furthermore, setting concerning the NR-PRACH is performed on the terminal device 40 in the connected state according to dedicated RRC signaling.

[0258] The terminal device 40 transmits the NR-PRACH using a physical resource (NR-PRACH occasion) in which the NR-PRACH can be transmitted. The physical resource is indicated by the setting concerning the NR-PRACH. The terminal device 40 selects any one of physical resources and transmits the NR-PRACH. Further, when the terminal device 40 is in the connected state, the terminal device 40 transmits the NR-PRACH using an NR-PRACH resource. The NR-PRACH resource is a combination of an NR-PRACH preamble and a physical resource of the NR-PRACH preamble. The base station 20 can indicate the NR-PRACH resource to the terminal device 40.

[0259] Note that the NR-PRACH is also transmitted when the random access procedure is unsuccessful. When retransmitting the NR-PRACH, the terminal device 40 waits for transmission of the NR-PRACH for a standby period calculated from a back-off value (a back-off indicator, BI). Note that the back-off value may be different depending on a terminal category of the terminal device 40 and a priority level of occurred traffic. At that time, a plurality of back-off values are notified and the terminal device 40 selects, according to the priority level, a back-off value to be used. When retransmitting the NR-PRACH, the terminal device 40 increases transmission power of the NR-PRACH compared to the transmission power in the first transmission. This procedure is called power ramping.

[0260] NR random access response (the Message 2) The NR random access response is transmitted using an NR-PDSCH (NR Physical Downlink Shared Channel). The NR-PDSCH including the random access response is scheduled by an NR-PDCCH (NR Physical Downlink Control Channel) in which a CRC (Cyclic Redundancy Check) is scrambled by an RA-RNTI. The NR-PDCCH is transmitted by a CORESET (Control Resource Set). The NR-PDCCH in which the CRC is scrambled by the RA-RNTI is arranged in a CSS (Common Search Space) of a Type1-PDCCH CSS set. Note that a value of the RA-RNTI(Random Access Radio Network Temporary Identifier) is determined based on transmission resources of the NR-PRACH corresponding to the random access response. The transmission resources of the NR-PRACH are, for example, a time resource (a slot or a subframe) and a frequency resource (a resource block). Note that the NR-PDCCH may be arranged in a search space associated with the NR-PRACH linked with the random access response. Specifically, the search space in which the NR-PDCCH is arranged is set in correlation with a preamble of the NR-PRACH and / or a physical resource in which the NR-PRACH is transmitted. The search space in which the NR-PDCCH is arranged is set in correlation with the preamble index and / or an index of the physical resource. The NR-PDCCH is quasi co-located (QCL) with an NR-SS (NR Synchronization signal).

[0261] The NR random access response is information concerning MAC (Medium Access Control). The NR random access response includes at least an uplink grant for transmitting the message 3 of the NR, a value of timing advance used to adjust uplink frame synchronization, and a value of a TC-RNTI. The NR random access response includes a PRACH index used for NR-PRACH transmission corresponding to the random access response. The NR random access response includes information concerning back-off used to waiting for transmission of the PRACH.

[0262] The base station 20 transmits the random access response on the NR-PDSCH. The terminal device 40 determines, from the information included in the random access response, whether transmission of a random access preamble has been successful. When determining that the transmission of the random access preamble has been successful, the terminal device 40 performs transmission processing for the message 3 of the NR according to the information included in the random access response. On the other hand, the transmission of the random access preamble has been unsuccessful, the terminal device 40 determines that the random access procedure has been unsuccessful and performs retransmission processing for the NR-PRACH.

[0263] Note that the NR random access response may include a plurality of uplink grants for transmitting the message 3 of the NR. The terminal device 40 can select one resource for transmitting the message 3 from the plurality of uplink grants. Accordingly, it is possible to relax contention of the transmission of the message 3 of the NR in the case in which different terminal devices 40 receive the random access response of the same NR. As a result, the communication system 1 can provide a more stable random access procedure.

[0264] Message 3 of the NR The message 3 of the NR is transmitted by an NR-PUSCH (NR Physical Uplink Shared Channel). The NR-PUSCH is transmitted by using a resource indicated by the random access response. The message 3 of the NR includes an RRC connection request message. A format of the NR-PUSCH is indicated by a parameter included in system information. For example, it is determined by the parameter which one of OFDM(Orthogonal Frequency Division Multiplexing) and DFT-s-OFDM (Discrete Fourier Transform Spread OFDM) is used as the format of the NR-PUSCH.

[0265] When the message 3 of the NR has been normally received, the base station 20 shifts to transmission processing for a contention resolution (the Message 4). On the other hand, when the NR message 3 has not been successfully normally received, the base station 20 attempts to receive the message 3 of the NR again for at least a predetermined period.

[0266] Another example of the instruction for retransmission of the message 3 and the transmission resource includes an instruction by the NR-PDCCH used for the instruction for retransmission of the message 3. The NR-PDCCH is an uplink grant. A resource for retransmission of the message 3 is indicated by DCI (Downlink Control Information) of the NR-PDCCH. The terminal device 40 retransmits the message 3 based on the instruction of the uplink grant.

[0267] Note that, when the reception of the contention resolution of the NR has not been successful within a predetermined period, the terminal device 40 regards that the random access procedure has been unsuccessful and performs the retransmission processing for the NR-PRACH. Note that a transmission beam of the terminal device 40 used for the retransmission of the message 3 of the NR may be different from a transmission beam of the terminal device 40 used for the first transmission of the message 3. Note that, when both of the contention resolution of the NR and the instruction for the retransmission of the message 3 have not been successfully received within the predetermined period, the terminal device 40 regards that the random access procedure has been unsuccessful and performs the retransmission processing for the NR-PRACH. The predetermined period is set by, for example, system information.

[0268] Contention resolution of the NR (the Message 4) The contention resolution of the NR is transmitted using the NR-PDSCH. The NR-PDSCH including the contention resolution is scheduled by the NR-PDCCH in which the CRC is scrambled by the TC-RNTI or the C-RNTI. The NR-PDCCH in which the CRC is scrambled by the TC-RNTI is arranged in the CSS of the Type1-PDCCH CSS set. Note that the NR-PDCCH may be arranged in a USS (User equipment specific Search Space). Note that the NR-PDCCH may be arranged in another CSS.

[0269] When normally receiving the NR-PDSCH including the contention resolution, the terminal device 40 transmits an acknowledgment (ACK) to the base station 20. Thereafter, the terminal device 40 regards that the random access procedure has been successful and shifts to the connected state (RRC_CONNECTED). On the other hand, when receiving a negative acknowledgement (NACK) for the NR-PDSCH from the terminal device 40 or when there is no response, the base station 20 retransmits the NR-PDSCH including the contention resolution. When the terminal device 40 has not successfully receive the contention resolution of the NR (the Message 4) within a predetermined period, the terminal device 40 regards that the random access procedure has been unsuccessful and performs the retransmission processing for the random access preamble (the Message 1).

[0270] <4-2-4. Two-STEP RACH of the NR> Subsequently, an example of a two-STEP RACH procedure (hereinafter referred to as two-step random access procedure) of the NR is explained. Fig. 19 is a diagram illustrating the two-step random access procedure. The two-step random access procedure includes two steps of a message A (step S41) and a message B (step S42). As an example, the message A includes the message 1 (the preamble) and the message 3 of the four-step random access procedure (four-STEP RACH procedure) of the related art and the message B includes the message 2 and the message 4 of the four-step random access procedure of the related art. Further, as an example, the message A includes a preamble (also referred to as PRACH) and a PUSCH and the message B includes a PDSCH.

[0271] By adopting the two-step random access procedure, the random access procedure can be completed with a lower delay compared with the four-step random access procedure of the related art.

[0272] The preamble and the PUSCH included in the message A may be set in linkage with transmission resources thereof or may be set by independent resources.

[0273] In the case in which the preamble and the PUSCH are set in linkage with the transmission resources, for example, when a transmission resource of the preamble is determined, a transmission resource of the PUSCH can be uniquely determined or a plurality of transmission resources of the PUSCH that can be candidates are determined. As an example, a time and frequency offset between a preamble of a PRACH occasion and a PUSCH occasion is decided by one value. As another example, the time and frequency offset between the preamble of the PRACH occasion and the PUSCH occasion is set to a different value for each preamble. The value of the offset may be determined by specifications or may be quasi-statically set by the base station 20. As an example of the value of the time and frequency offset, for example, the value is defined by a predetermined frequency. For example, in an unlicensed band (for example, a 5 GHz band, band 45), a value of a time offset can be set to 0 or a value close to 0. Accordingly, it is possible to omit LBT (Listen Before Talk) before transmission of the PUSCH.

[0274] On the other hand, when the transmission resources of the preamble and the PUSCH are set by independent resources, the transmission resource of each of the preamble and the PUSCH may be determined by specifications, the resources may be quasi-statically set by the base station 20, or the resources may be determined from another kind of information. Examples of the other kind of information include slot format information (for example, Slot Format Indicator), BWP (Band Width Part) information, preamble transmission resource information, a slot index, and a resource block index. When the transmission resources of the preamble and the PUSCH are set by independent resources, linkage between the preamble and the PUSCH configuring one message A may be notified to the base station 20 by a payload of the PUSCH or a UCI included in the PUSCH or may be notified to the base station 20 by transmission physical parameters of the PUSCH (for example, a scrambling sequence of the PUSCH, a DMRS sequence and / or pattern, or a transmission antenna port of the PUSCH).

[0275] In addition, a method of setting the transmission resources of the preamble and the PUSCH may switch a case in which the transmission resources are set in linkage and a case in which the transmission resources are set by independent resources. For example, the case in which the transmission resources are set by independent resources may be applied in a license band and the case in which the transmission resources are set in linkage may be applied in an un-license band.

[0276] The random access procedure in which it is assumed that the RAT supported by the communication system 1 is the NR is explained above. Note that the random access procedure explained above can also be applied to a RAT (for example, the 5G, the B5G, or the 6G or the later generation RAT) other than the NR. The random access procedure explained above is also applicable to cell-free communication.

[0277] <<5. Operation of the communication system>> Based on the above, an operation of the communication system 1 is explained in detail.

[0278] <5-1. Explanation of technologies / terms> Some technologies / terms that are the premise of the explanation of the operation of the communication system 1 is explained.

[0279] <5-1-1. Antenna port> First, an antenna port is explained.

[0280] An antenna port in the present embodiment is used to recognize whether propagation path characteristics are the same. For example, in the same antenna port, it can be recognized that propagation path characteristics in one symbol are the same as propagation path characteristics in another symbol. In addition, different antenna ports are recognized to have different propagation path characteristics unless the antenna ports are a QCL(Quasi-co-location).

[0281] The antenna port may be used to correlate a predetermined reference signal and a predetermined channel. The communication device can regard that the predetermined reference signal and the predetermined channel correlated with each other are the same propagation path characteristics. For that reason, a communication device on a reception side can estimate propagation path characteristics with the predetermined reference signal and perform, based on the estimated propagation path characteristics, reception processing on the predetermined channel correlated with the predetermined reference signal.

[0282] <5-1-2. TCI state and QCL> Subsequently, a TCI state (Transmission Configuration Indication state) and a QCL (Quasi-co-location) are explained.

[0283] In wireless communication, reception processing for a signal and / or a channel is sometimes performed based on a TCI state. Here, the reception processing may be, for example, at least one of reception, de-mapping, demodulation, and decoding. Here, the TCI state is information concerning a QCL of the signal and / or the channel. The TCI state may be called spatial reception parameter, spatial relation information, or the like. The TCI state is set in a communication device, for example, for each channel or each signal.

[0284] The QCL indicates statistical natures of the signal and / or the channel. For example, the QCL indicates a relationship between antenna ports. For example, when transmission of a signal between different antenna ports can be estimated based on a specific channel characteristic, a relation between the antenna ports can be regarded as a quasi-co-location (QCL). In other words, when a characteristic of a signal on another antenna port can be estimated from a characteristic of a signal on one antenna port, a relation between the antenna ports can be regarded as the QCL. For example, when a certain signal and / or channel and other signals and / or channels are the QCL, it can be assumed that at least one of Doppler Shift, Doppler Spread, Average Delay, Delay Spread, and Spatial Parameter is the same among these different plurality of signals and / or channels.

[0285] For example, it is assumed that a reference signal X and a reference signal Y are transmitted from the same antenna array and the same spatial filter is applied to the signals. In this case, the reference signal X and the reference signal Y have similar channel characteristics. Therefore, a communication device on a reception side (hereinafter also referred to as reception device) can detect the reference signal Y using the channel characteristics of the reference signal X. In such a case, the reference signal X and the reference signal Y can be regarded as QCLs.

[0286] Here, the reference signal X can be a signal such as a CSI-RS(Channel State Information Reference Signal) or an SSB (SS / PBCH Block). SS means Synchronization Signal and PBCH means Physical Broadcast Channel. The reference signal Y can be a channel such as a PDCCH (Physical Downlink Control Channel), a PDSCH (Physical Downlink Shared Channel), a PUCCH (Physical Uplink Control Channel), a PUSCH (Physical Uplink Shared Channel), a PSCCH (Physical Sidelink Control Channel), or a PSSCH (Physical Sidelink Shared Channel). For example, when a predetermined CSI-RS and a predetermined PDCCH are QCLs, the reception device can execute reception processing for the PDCCH assuming that predetermined channel characteristics for receiving the PDCCH are the same as predetermined channel characteristics of the CSI-RS.

[0287] Channel characteristics concerning the QCL may be some or all of a plurality of channel characteristics indicated by (D1) to (D5) below.

[0288] (D1) Doppler Shift A Doppler shift indicates a change in a wavelength due to movement of the communication device. The Doppler shift is a phenomenon in which a frequency of a transmission signal changes according to speed.

[0289] (D2) Doppler Spread A Doppler spread is, for example, a temporal representation of the difference between frequencies of a transmission signal and a reception signal. The Doppler spread indicates a spread of the received signal.

[0290] (D3) Average Delay An average delay indicates, for example, an average value of arrival times of signals by multipath propagation.

[0291] (D4) Delay Spread A delay spread (delay dispersion) indicates, for example, an arrival time difference between a first multipath component and a last component.

[0292] (D5) Spatial Parameter A spatial parameter is information relating to beamforming. The spatial parameter may be a spatial reception parameter (Spatial Rx Parameter). At this time, the spatial reception parameter may correspond to a reception beam (for example, a reception analog beam) of the reception device. In this case, the reception device may identify the beam based on the spatial parameter.

[0293] A QCL between antenna ports is specified by a TCI state. For example, the TCI state can include parameters for setting a QCL relation between a downlink reference signal (for example, a DMRS (DeModulation Reference Signal)) and an antenna port of the PDSCH, a QCL relation between a downlink reference signal (for example, DMRS) and an antenna port of the PDCCH, a QCL relation between a downlink reference signal (for example, DMRS) and an antenna port of an NZP-CSI-RS(Non-zero-power Channel State Information Reference Signal) resource, or the like. For example, the TCI state is defined by QCL types (QCL-Types) explained below.

[0294] (QCL Type A) Parameter set: Doppler shift, Doppler spread, mean delay, and delay spread

[0295] (QCL Type B) Parameter set: Doppler shift and Doppler spread

[0296] (QCL Type C) Parameter set: Doppler spread and average delay

[0297] (QCL Type D) Parameter set: spatial parameter

[0298] Note that the QCL types are not limited to the above. Further, other QCL types may be defined.

[0299] The terminal device 40 can designate the TCI state with at least one of DCI (Downlink Control Information), MAC CE (Medium Access Control Element), and RRC (Radio Resource Control) signaling.

[0300] Note that the terminal device 40 may receive the TCI state for a predetermined channel (for example, PDCCH, PDSCH, PUCCH, PUSCH, PSCCH, or PSSCH) with the RRC.

[0301] For example, the terminal device 40 may receive information concerning activation / deactivation of the TCI state of a terminal device-specific PDSCH with the MAC CE. The terminal device 40 may receive a TCI state indication for a terminal device-specific PDCCH with the MAC CE. The terminal device 40 may receive a TCI state indication for the PDSCH with the DCI.

[0302] A downlink transmission beam can be defined by an index and a QCL of a predetermined signal.

[0303] Examples of the predetermined signal include an SS / PBCH block. For example, a plurality of SS / PBCH blocks having different indexes and having the same information may be transmitted. The SS / PBCH blocks having the different indexes may be transmitted by different transmission beams. A relationship between beams of another reference signal and a physical channel is determined by TCI states of an SS / PBCH block having a predetermined index and a DMRS of the other reference signal or the physical channel.

[0304] Examples of the predetermined signal include a NZP-CSI-RS. For example, a plurality of NZP-CSI-RS resources may be set. CSI-RS ports of different CSI-RS resources may be transmitted by different transmission beams. The relationship between the beams of the other reference signal and the physical channel is determined by TCI states of a CSI-RS port of a CSI-RS resource and the DMRS of the other reference signal or the physical channel. Note that, in the present embodiment, the NZP-CSI-RS is sometimes simply called CSI-RS.

[0305] Note that the terminal device 40 may receive a common TCI state for a predetermined channel (for example, PDCCH, PDSCH, PUCCH, PUSCH, PSCCH, or PSSCH) with the RRC. The terminal device 40 may receive a predetermined signal. The terminal device 40 may receive the predetermined channel assuming that the predetermined channel is QCL with a predetermined signal based on the common TCI state. For example, when the QCL type B is set by the common TCI state, the terminal device 40 may perform reception processing for the predetermined channel assuming that a Doppler shift and a Doppler spread of the predetermined signal are the same. Accordingly, reception characteristics (for example, at least one of communication quality, demodulation performance, and decoding performance) of the predetermined channel are improved compared with a case in which there is no signal for which a QCL is assumed.

[0306] <5-1-3. Common information and UE-dedicated information> Subsequently, common information and UE-dedicated information are explained.

[0307] (Common information) In the present embodiment, the common information indicates control information transmitted in common to a plurality of UEs (a plurality of terminal devices 40). For example, the common information is control information transmitted in common to all UEs within the coverage of a communication point (for example, in a cell). Alternatively, the common information may be control information transmitted in common to a plurality of terminal devices 40 belonging to a predetermined UE group. Note that, in the present embodiment, signaling sometimes means a signal / information transmitted by the signaling. In this case, the common information can be rephrased as common signaling or common RRC signaling.

[0308] The common information mainly has characteristics explained below. Note that the common information may not always have all of the characteristics explained below.

[0309] ・ The common information is transmitted through a broadcast channel (for example, a BCCH). ・ The common information can be received by all UEs within a coverage (for example, in a cell). ・ The common information mainly includes system information and / or information concerning initial access. ・ For example, the common information is an MIB and / or an SIB. ・ The common information provides information necessary for initial connection of a UE and / or cell selection / reselection of the UE. ・ The common information can be received by all UEs regardless of a UE state. In particular, the common information can be used by a UE of RRC_IDLE to obtain information concerning a communication point or a communication system of the UE. ・ The common information is control information used when a UE for which UE-dedicated information (for example, individual RRC signaling (Dedicated RRC signaling)) is not set performs transmission and reception to and from the communication point.

[0310] (UE-dedicated information) In the present embodiment, the UE-dedicated information indicates control information individually transmitted to a specific UE (a specific terminal device 40). The UE-dedicated information may be rephrased as individual information, UE-specific information, or specific information. As explained above, in the present embodiment, signaling sometimes means a signal / information transmitted by the signaling. In this case, the UE-dedicated information may be rephrased as dedicated signaling or dedicated RRC signaling.

[0311] The UE-dedicated information mainly has characteristics explained below. Note that the UE-dedicated information may not always have all of the characteristics explained below.

[0312] ・ The UE-dedicated information is transmitted through a dedicated control channel (for example, a DCCH). ・ The UE-dedicated information is used for one-to-one communication between a specific UE and a network. ・ The UE-dedicated information includes UE-specific setting and control information. ・ For example, the UE-dedicated information is an RRCReconfiguration message. ・ The UE-dedicated information is used for control of establishment / correction / release of connection, handover, or the like. ・ The UE-dedicated information is information set by a UE in a RRC_CONNECTED state.

[0313] <5-1-4. UE state> Subsequently, a UE state is explained.

[0314] As the UE state, three states of RRC_CONNECTED, RRC_INACTIVE, and RRC_IDLE can be specified.

[0315] (Characteristics of RRC_CONNECTED) The RRC_CONNECTED mainly has characteristics explained below. Note that the RRC_CONNECTED may not always have all of the characteristics explained below.

[0316] ・ The RRC_CONNECTED is a state in which RRC connection is established between a UE and a communication point. ・ In the RRC_CONNECTED, user data can be transmitted and received. In the RRC_CONNECTED, control signaling can also be performed. ・ In the RRC_CONNECTED, the location of the UE is grasped at a cell level. ・ In the RRC_CONNECTED, both the UE and an RAN maintain an access stratum (AS) context. ・ The RRC_CONNECTED is a state in which power consumption is the highest.

[0317] (Characteristics of the RRC_ INACTIVE) The RRC_INACTIVE mainly has characteristics explained below. Note that the RRC_INACTIVE may not always have all of the characteristics explained below.

[0318] ・ In the RRC_INACTIVE, both of the UE and the communication point maintain at least part of the AS context. ・ In the RRC_INACTIVE, the location of the UE is grasped at an RAN notification area (RNA) level. ・ In the RRC_INACTIVE, core network connection (NAS connection) is maintained. ・ In the RRC_INACTIVE, quick transition to the RRC_CONNECTED is possible. ・ In the RRC_INACTIVE, mobility by cell reselection is performed without network involvement. ・ The RRC_INACTIVE has an intermediate characteristic between the RRC_CONNECTED and the RRC_IDLE.

[0319] (RRC_IDLE) The RRC_IDLE mainly has characteristics explained below. Note that the RRC_IDLE may not always have all of the characteristics explained below.

[0320] ・ The RRC_IDLE is equivalent to an initial state of the UE. ・ In the RRC_IDLE, both of the UE and the RAN release the AS context. ・ In the RRC_IDLE, an accurate location of the UE is not grasped by the RAN. ・ The RRC_IDLE is a state in which power consumption is the lowest. ・ The UE in the RRC_IDLE state needs to establish RRC connection for data transmission and reception.

[0321] (Characteristics of state transition of the UE) The state transition of the UE mainly has characteristics explained below. Note that the state transition of the UE may not always have all of the characteristics explained below.

[0322] ・ No direct transition from the RRC_IDLE to the RRC_INACTIVE is possible. ・ Transition from the RRC_INACTIVE to the RRC_CONNECTED is faster than transition from the RRC_IDLE. ・ Transition from the RRC_CONNECTED to the RRC_INACTIVE is controlled by a communication point after expiration of an inactivity timer.

[0323] (Others) For example, with these state managements, the communication system 1 in the present embodiment can implement a load reduction of network signaling, a reduction in latency, and improvement in power efficiency.

[0324] <5-1-5. Others> In the following explanation, a resource represents, for example, a frequency, a time, a resource element (a REG, a CCE, and a CORESET), a resource block, a bandwidth part, a component carrier, a symbol, a sub-symbol, a slot, a mini-slot, a subslot, a subframe, a frame, a PRACH occasion, an occasion, a code, a multi-access physical resource, a multi-access signature, or a subcarrier spacing (numerology).

[0325] In the following explanation, when a specific example is explained, there is a part explained by indicating a specific value. However, the value is not limited to the example and another value may be used.

[0326] <5-2. Overview of an operation of the communication system> Subsequently, an overview of an operation of the communication system 1 in the present embodiment is explained.

[0327] In the present embodiment, the common information (for example, common RRC signaling) includes one or a plurality of TCI states. That is, a communication point (for example, the transmission control unit 432 of the base station 20) transmits, as common information, information concerning a TCI state including one or a plurality of TCI states. At this time, a communication point (for example, the acquisition unit 431 of the base station 20) may acquire one or a plurality of TCI states to be included in the information concerning the TCI state from another device or from a storage unit of the communication point (for example, the storage unit 42 of the base station 20). Note that these controls may be performed by the communication point itself or may be performed by another device that controls one or a plurality of communication points (for example, the control unit 23 of the base station 20 that controls one or a plurality of communication points).

[0328] The UE (for example, the reception control unit 433 of the terminal device 40) receives the information concerning the TCI state transmitted from the communication point as the common information. The information concerning the TCI state is, for example, a TCI state list including one or a plurality of TCI states. The UE (for example, the communication control unit 434 of the terminal device 40) performs processing concerning the multilink connection based on TCI states of a respective plurality of communication points.

[0329] In the present embodiment, the TCI state list transmitted as the common information is referred to as common TCI state list. The common TCI state list can also be called common TCI state set, common TCI state information, information concerning the common multilink connection, or information concerning a common multi-TRPs.

[0330] In the present embodiment, a TCI state list individually transmitted to a specific UE is referred to as dedicated TCI state list. The dedicated TCI state list can also be called specific TCI state list, dedicated TCI state information, specific TCI state information, information concerning dedicated multilink connection, information concerning specific multilink connection, information concerning dedicated multi-TRP, or information concerning specific multi-TRP. "Dedicated" may be rephrased as "UE-dedicated". "Specific" may be rephrased as "UE-specific".

[0331] In the following explanation, the "information concerning the TCI state" is sometimes referred to as "TCI state list". The "TCI state list" appearing in the following explanation can be replaced with "information concerning the TCI state".

[0332] According to the present embodiment, it is possible to implement the multilink connection (for example, multi-TRP transmission and reception) in a control plane. For example, according to the present embodiment, even in a state in which the dedicated TCI state list is not set, the UE can perform the multilink connection based on the common TCI state list. Alternatively, even if a problem occurs in connection based on the dedicated TCI state list, the UE can perform the multilink connection based on the common TCI state list. As explained above, the information concerning the TCI state including the one or plurality of TCI states is transmitted or received as the common information, whereby various advantages (use cases, embodiments) can be implemented.

[0333] (Method of setting the TCI state list) Here, a method of setting (or using) the TCI state list is exemplified. Examples of the method of setting the TCI state list include methods indicated by the following (E1) to (E5). Note that the methods explained below can be applied to both of the setting of the common TCI state list and the setting of the dedicated TCI state list.

[0334] The setting of the TCI state list (the common TCI state list and / or the dedicated TCI state list) can be implemented by any one of the methods indicated by the following (E1) to (E5) or a combination thereof. In particular, the setting and / or notification of the TCI state list can be implemented by any one of RRC signaling, MAC signaling, and PHY signaling or a combination thereof.

[0335] Note that, in examples explained below, a communication method using some or all of the plurality of setting methods explained below is explained. However, the method of setting the TCI state list is not limited to the methods exemplified below. The communication point (for example, a BS or a communication node under the control of the BS) in the present embodiment is capable of setting the TCI state list using other setting methods. Hereinafter, specific examples of the method of setting the TCI state list are explained.

[0336] (E1) Setting method 1 The communication point may set one TCI state list in the UE with the RRC signaling. The UE may transmit or receive information / signals assuming that the TCI state list is always active.

[0337] (E2) Setting method 2 The communication point may set one or a plurality of TCI state lists in the UE with the RRC signaling. The UE may transmit or receive information / signals assuming that the one or plurality of TCI state lists are always active. The UE may select the one or plurality of TCI state lists based on a predetermined condition and transmit or receive information / signals using the selected TCI state list. The UE may transmit or receive information / signals assuming that any one of the one or plurality of TCI state lists is used (blind transmission and reception). In the blind transmission and reception, the UE may attempt to transmit or receive information / signals using each of the one or plurality of TCI state lists. Then, the UE may transmit or receive information / signals using a TCI state list that was successfully transmitted or received among the one or plurality of TCI state lists.

[0338] (E3) Setting method 3 The communication point may set one candidate TCI state list in the UE with the RRC signaling. Then, the communication point may activate / deactivate the candidate TCI state list with other signaling (the RRC / MAC / PHY signaling). Only when the TCI state list is active, the UE may transmit or receive information / signals based on the list. When the TCI state list is inactive, the UE may transmit or receive information / signals with another method (at least, the UE transmits or receives information / signals without assuming the TCI state list).

[0339] (E4) Setting method 4 The communication point may set one or a plurality of candidate TCI state lists in the UE with the RRC signaling. Then, the communication point may activate / deactivate one of the one or plurality of candidate TCI state lists with other signaling (the RRC / MAC / PHY signaling). The UE may transmit or receive information / signals based on the active TCI state list. In the setting method 4, one of the one or plurality of candidate TCI state lists is always active. That is, the UE operates without assuming a case in which none of the one or plurality of candidate TCI state lists is active. Note that, when a default TCI state list is set or selected and a TCI state list is not activated by other signaling, the UE may transmit or receive information / signals based on the default TCI state list.

[0340] (E5) Setting method 5 The communication point may set one or a plurality of candidate TCI state lists in the UE with the RRC signaling. Then, the communication point may activate / deactivate one or more of the one or plurality of candidate TCI state lists with another signaling (the RRC / MAC / PHY signaling). At this time, all of one or more candidate TCI state lists may be collectively activated / deactivated or some of the one or more candidate TCI state lists may be individually activated / deactivated. The UE may select one or more active TCI state lists under predetermined conditions and use the selected one or more active TCI state lists to transmit or receive information / signals. The UE may also transmit or receive information / signals assuming that any one of those one or more active TCI state lists is used (blind transmit and receive). In the blind transmission and reception, the UE may attempt to transmit or receive information / signals using each of the one or more TCI state lists. Then, the UE may transmit or receive information / signals using a successfully transmitted or received TCI state list among the one or more active TCI state lists.

[0341] (Others) A target of a TCI state list (a connection target of the UE) may be the cluster explained above. Here, the cluster may be a set of communication points determined by (correlated with / corresponding to) the setting and / or notification of the TCI state list. For example, the cluster may be a set of communication points correlated with / corresponding to the TCI state list.

[0342] The communication device (for example, the UE / the communication point) may individually set a common TCI state list by a downlink (DL), an uplink (UL), and a sidelink (SL). Alternatively, the communication device may switch the common TCI state list by the DL, the UL, and the SL. The communication device may set the common TCI state list only for communication (transmission and / or reception) on a predetermined link (for example, the DL, the UL, or the SL) depending on a use case (a condition). Alternatively, the communication device may switch the common TCI state list only in the case of communication (transmission and / or reception) on a predetermined link depending on a use case (a condition).

[0343] In a pair spectrum (for example, a FDD (Frequency Division Duplex) band), the communication device (for example, UE / communication point) may individually set the common TCI state list in respective spectra (frequencies / component carriers). The communication device may simultaneously set the common TCI state list in respective spectra (frequencies / component carriers) in an unpair spectrum (for example, a TDD (Time Division Duplex)band).

[0344] In the pair spectrum (for example, the FDD band), the communication device (for example, the UE / the communication point) may individually switch the common TCI state list in respective spectra (frequencies / component carriers). The communication device may simultaneously switch the common TCI state list in the respective spectra (the frequencies / the component carriers) in the unpair spectrum (for example, the time division duplex (TDD) band).

[0345] When a predetermined problem (for example, a communication failure) occurs in the multilink connection in which the common TCI state list is used, the communication device (for example, the UE / the communication point) may fall back connection between the UE and one or a plurality of communication points from the multilink connection to single link connection (the communication method of the related art). The communication device (for example, the UE) may determine, based on a predetermined condition, whether to execute the fallback.

[0346] The communication device (for example, the UE / the communication point) may dynamically or quasi-statically update (change) the common TCI state list. Accordingly, when a signal / a channel is transmitted on demand, the communication device can change the TCI state included in the common TCI state list to only a TCI state of the communication point that transmits the signal / the channel on demand (that is, a valid TCI state).

[0347] Here, the signal / the channel is, for example, a first downlink signal (hereinafter referred to as first DL signal), a first downlink channel (hereinafter referred to as first DL channel), a second downlink signal (hereinafter referred to as second DL signal), or a second downlink channel (hereinafter referred to as second DL channel). The first DL signal, the first DL channel, the second DL signal, or the second DL channel is explained below.

[0348] For example, it is assumed that the communication device (for example, the BS / the communication points) sets the common TCI state list in the UE with the RRC signaling. In this case, the communication device may dynamically notify, with the PDCCH signaling, to the UE, the TCI state (that is, the valid TCI state) of the communication point that transmits the signal / the channel. Accordingly, the common TCI state list included in the UE can be updated.

[0349] For example, it is assumed that the communication point has set the common TCI state list in the UE with the RRC signaling. In this case, when the communication point has updated the common TCI state list of the communication point, the communication point may dynamically notify the update to the UE with the PDCCH signaling. Then, the UE may receive the updated common TCI state list with the RRC signaling. This also enables update of the common TCI state list included in the UE.

[0350] The common TCI state list may include information indicating a use purpose (a use case) of the common TCI state list. Examples of the purpose (the use case) include some or all of examples explained below.

[0351] In the examples explained below, the UE sometimes performs communication using three communication points having different TCI states. Hereinafter, these three communication points are referred to as communication point P1, a communication point P2, and a communication point P3. In this case, the communication point P2and the communication point P3are communication points that transmit or receive signals / information to and from the UE by the multilink connection. The communication point P1is a communication point used by the UE to transmit or receive control information for performing the multilink connection with the communication point P2and the communication point P3.

[0352] Note that the communication point P1is a communication point recognized by the UE as a communication point having a TCI state different from a TCI state of the other communication points (the communication point P2and the communication point P3). The UE may not recognize what kinds of forms forms of the plurality of communication points (the communication point P1, communication point P2, and communication point P3) are.

[0353] In the following explanation, the communication point P1is sometimes referred to as first communication point and the communication point P2and the communication point P3are sometimes referred to as second communication points. The second communication points are not limited to the two communication points P2and P3. Three or more second communication points may be present. A form in which only one second communication point is present can be assumed.

[0354] Note that at least two forms of an actual plurality of communication points can be conceived. For example, the first communication point may be a communication point different from both of the plurality of second communication points (a first form). For example, the first communication point may be the same communication point as at least one of the plurality of second communication points (a second form).

[0355] (Example of the first form) Fig. 20 is a diagram illustrating an example of a form of a plurality of communication points. In the example illustrated in Fig. 20, the first communication point (the communication point P1) is a communication point different from both of the plurality of second communication points (the communication point P2and the communication point P3). In the example illustrated in Fig. 20, there is one first communication point. However, a plurality of first communication points may be present. In the example illustrated in Fig. 20, two second communication points are present. However, three or more second communication points may be present.

[0356] (Example of the second form) Fig. 21 is a diagram illustrating another example of the form of a plurality of communication points. In the example illustrated in Fig. 21, the plurality of second communication points (the communication point P2and the communication point P3) respectively also function as the first communication point (the communication point P1). That is, the first communication point is the same communication point as the second communication point. Note that, in the example illustrated in Fig. 21, all of the plurality of second communication points (for example, both the communication point P2and the communication point P3) function as the communication point P1. However, not all of the plurality of second communication points always need to function as the first communication point. For example, one second communication point among the plurality of second communication points or two or more second communication points among the plurality of second communication points may function as the first communication point. In the example illustrated in Fig. 21, only one of the communication point P2and the communication point P3may function as the communication point P1. In the example illustrated in Fig. 21, two second communication points are present. However, three or more second communication points may be present.

[0357] The overview of the operation of the communication system 1 is explained above. The operation of the communication system 1 is explained in detail below. Hereinafter, the operation is divided into four examples and explained. Note that four examples (a first example to a fourth example) explained below can be combined as appropriate.

[0358] <5-3. First example> First, an operation of the communication system 1 according to the first example is explained.

[0359] In the first example, the common TCI state list is transmitted in report information (for example, system information) and used for DL channel reception processing.

[0360] For example, in the first example, the communication point transmits the common TCI state list to the UE using predetermined report information. The predetermined report information is, for example, an MIB (Master Information Block) and / or an SIB (System Information Block). Note that the MIB may be transmitted on a PBCH (Physical broadcast channel). The SIB may be transmitted on a PDSCH (Physical Downlink Shared Channel). Note that a plurality of types of SIBs (for example, an SIB1 and an SIB2) can be specified according to a purpose and / or importance of control information.

[0361] In the first example, the common TCI state list is used for reception processing for a predetermined DL channel. With the method explained in the first example, the UE (the terminal device 40) can perform the multilink connection to a predetermined DL channel. Here, the predetermined DL channel can include other report information.

[0362] Fig. 22 is a sequence diagram illustrating communication processing according to the first example. In an example illustrated in Fig. 22, the communication processing is performed between one UE and a plurality of communication points (in the example illustrated in Fig. 22, the communication point P1to the communication point P3).

[0363] Note that processing of the communication point P (at least one of the communication point P1to the communication point P3) explained below may be performed by the communication point P itself or may be performed by a control device that controls the communication point P (for example, the control unit 23 of the base station 20 that controls the communication point P). The processing of the UE explained below may be performed by the control unit 43 of the UE (the terminal device 40).

[0364] In the first example, it is assumed that the plurality of communication points P (in the example illustrated in Fig. 22, three communication points) are respectively different from other communication points in TCI states. In the following explanation, the TCI state of the communication point P1is sometimes referred to as TCI state 1, the TCI state of the communication point P2is sometimes referred to as TCI state 2, and the TCI state of the communication point P3is sometimes referred to as TCI state 3.

[0365] In addition, in the following explanation, transmitting a signal / information on a channel is sometimes referred to as transmission of a channel and receiving a signal / information transmitted on the channel is sometimes referred to as reception of a channel. For example, transmitting information (for example, system information) on a broadband channel is sometimes referred to as transmission of a broadband channel and receiving the information transmitted on the broadband channel is sometimes referred to as reception of a broadband channel. Here, the predetermined channel can be any channel.

[0366] Hereinafter, the communication processing according to the first example is explained with reference to the sequence diagram of Fig. 22.

[0367] First, the communication point P1transmits (reports) a first DL signal and a first DL channel (a first channel) (step S101).

[0368] (First DL signal) Here, the first DL signal may be a signal having a characteristic indicated by at least one of (F1) to (F5) explained below.

[0369] (F1) Signal detected before reception of a second DL signal For example, the first DL signal may be a signal that the UE detects before receiving the second DL signal.

[0370] (F2) Signal for performing predetermined processing For example, the first DL signal may be a signal for the UE to perform predetermined processing. Here, the predetermined processing may be, for example, at least one of time synchronization, frequency synchronization, recognition of a cell ID, recognition of a resource of report information, and reception processing for the report information.

[0371] (F3) Synchronization signal For example, the first DL signal may be a synchronization signal having a function / a purpose / a configuration that are the same as or similar to those of a PSS / a SSS included in the SSB (the SS / PBCH block) in the 5G.

[0372] (F4) Signal received before reception of information concerning the common TCI state list For example, the first DL signal may be a signal that the UE receives before or to receive information concerning the common TCI state list. The information concerning the common TCI state list may be the common TCI state list itself.

[0373] (F5) Signal corresponding to the TCI state of the communication point P1 For example, the first DL signal may be a signal corresponding to the TCI state of the communication point P1(that is, the TCI state 1).

[0374] (First DL channel) The first DL channel (the first channel) may be a channel having a characteristic indicated by least one of (G1) to (G6) explained below.

[0375] (G1) Channel detected before reception of the second DL signal For example, the first DL channel may be a channel that the UE detects before reception of the second DL signal.

[0376] (G2) Channel for performing predetermined processing For example, the first DL channel may be a channel for the UE to perform predetermined processing. Here, the predetermined processing may be, for example, reception processing for the second DL signal.

[0377] (G3) Channel including information concerning the common TCI state list For example, the first DL channel may be a channel including information concerning the common TCI state list. The information concerning the common TCI state list may be the common TCI state list itself.

[0378] (G4) Broadcast channel For example, the first DL channel may be a channel a function / a purpose / a configuration that are the same as or similar to those of the PBCH in the 5G.

[0379] (G5) Channel for notification of report information For example, the first DL channel may be a channel used for notification of information having a function / a purpose / a configuration that are the same as or similar to those of the report information (the common control information) in the 5G. Here, the report information may be, for example, an MIB and / or an SIB.

[0380] (G6) Signal corresponding to the TCI state 1 For example, the first DL signal may be a channel corresponding to the same TCI state (that is, the TCI state 1) as the TCI state of the first DL signal.

[0381] Subsequently, the UE receives the first DL signal and the first DL channel. Here, the UE may perform the reception processing for the first DL channel based on a TCI state assumed based on the first DL signal (step S102). Then, the UE acquires information concerning the common TCI state list notified on the first DL channel (step S103). The information concerning the common TCI state list may be the common TCI state list itself.

[0382] (Parameter for setting information concerning a QCL) Note that the information concerning the common TCI state list may include a parameter for setting information (a Quasi co-location relationship) concerning a QCL.

[0383] Here, the information concerning the QCL may include information concerning a channel (hereinafter also referred to as QCL channel) assumed to be QCL with the second DL signal. Here, the QCL channel may be, for example, a PDSCH including a predetermined SIB and / or a PDCCH that schedules the PDSCH. In the first example, for example, a second DL channel (a second channel) explained below can be equivalent to the QCL channel. Note that the QCL channel may be specified in advance. In this case, the communication point may not transmit information concerning the QCL channel.

[0384] The information concerning the QCL may include information concerning a QCL type. At this time, the QCL type may be, for example, QCL type D. Note that the QCL type may be specified in advance. In that case, the communication point may not transmit information concerning the QCL type. In this case, the UE may perform reception processing / transmission processing (for example, processing concerning the multilink connection) of the QCL channel based on the QCL type (for example, the QCL type D) specified in advance and information concerning another QCL (for example, information concerning a QCL channel).

[0385] (Information concerning the second DL signal) The information concerning the common TCI state list may include information concerning the second DL signal. The information concerning the second DL signal is, for example, information necessary for the UE to receive the second DL signal. For example, the information concerning the second DL signal is information for specifying a transmission resource of the second DL signal.

[0386] The information concerning the second DL signals may also be a list of one or a plurality of second DL signals that the UE is likely to receive or the UE should receive. In this case, the second DL signal included in the list may be all of second DL signals transmitted / managed / controlled by a communication point that transmits the first DL signal and / or the first DL channel (or a communication node for controlling the communication point). Alternatively, the second DL signals included in the list may be some second DL signals determined according to, for example, the location of the UE.

[0387] The information concerning the second DL signal may include at least one of pieces of information explained below. ・ ID (for example, a TCI state ID) for identifying each of the plurality of second DL signals ・ Number of second DL signals that the UE is likely to receive or the UE should receive ・ Information concerning transmission resources (for example, time and frequency resources) of each of the plurality of second DL signals ・ Information concerning transmission power of each of the plurality of second DL signals ・ Subcarrier spacing of each of the plurality of second DL signals ・ When the plurality of second DL signals are subjected to code division multiplexing, information concerning an orthogonal code (a code index) ・ When ae scramble code is superimposed on the second DL signal (when the second DL signal is generated based on the scramble code), information concerning the scramble code

[0388] Note that the information concerning the second DL signal does not always need to be explicitly (explicitly) notified by the information concerning the common TCI state list. The information concerning the second DL signal may be implicitly notified. For example, the information concerning the second DL signal may be implicitly determined by a predetermined signal, a channel, information, or the like. Hereinafter, implicit notification of a transmission resource (for example, time and frequency resources) of the second DL signal is explained. Note that items explained below are similarly applicable to implicit notification of another parameter (for example, at least one of transmit power, a subcarrier spacing, an orthogonal code, and a scramble code).

[0389] (Implied notification example 1) For example, some of the transmission resources of the second DL signal are the same as the transmission resources of the first DL signal and / or the first DL channel. Here, the transmission resource assumed to be the same may be at least one of a BWP (Bandwidth part), an RB, an RB set, a slot, and a system frame.

[0390] (Implicit notification example 2) For example, some of the transmission resources of the second DL signal are determined based on the transmission resources of the first DL signal and / or the first DL channel. For example, the transmission resources of the second DL signal are determined assuming that a predetermined number of resources are shifted from the transmission resources of the first DL signal and / or the first DL channel. The predetermined number can be notified by information concerning the common TCI state list.

[0391] The UE receives one or a plurality of second DL signals based on the common TCI state list (step S104A, step S104B). In the example illustrated in Fig. 22, the communication point P2and the communication point P3respectively transmit the second DL signals. These second DL signals can be multiplexed. For example, the second DL signals can be multiplexed in at least one of a time, a frequency, and a space (a code).

[0392] Note that, in the example illustrated in Fig. 22, the communication point P2and the communication point P3respectively transmit the second DL signals. However, a transmission mode of the second DL signals is not limited to this example. The UE only has to be assumed to be a QCL. For example, the second DL signals may be transmitted from a communication point different from the communication point P2and the communication point P3.

[0393] (Second DL signal) Here, the second DL signal may be a signal having a characteristic indicated by at least one of (H1) to (H4) explained below.

[0394] (H1) Reference signal For example, the second DL signal may be a reference signal transmitted from a communication point included in the common TCI state list. In other words, the second DL signal may be a reference signal that the UE recognizes as being transmitted from a predetermined communication point. Note that the UE can recognize that a QCL (a TCI state) of the second DL signal is different from the QCL of the first DL channel and / or the QCL of the first DL signal.

[0395] (H2) Signal for measuring communication quality For example, the second DL signal may be a signal for measuring (or detecting, recognizing, or surveying) communication quality for communication points included in the common TCI state list. For example, the second DL signal may be a signal used to select a communication point and / or report communication quality in the initial access control.

[0396] Here, the communication quality may be RSRP, may be RSRQ, may be RSSI, may be SINR, may be SNR, may be SIR, may be CSI, may be CQI, may be PMI, or may be RI.

[0397] The RSRP (Reference Signal Received Power) indicates a power level of a reference signal received from a specific communication point. This value indicates how strongly a receiver is receiving the reference signal. The RSRP is used to, for example, evaluate the quality of communication.

[0398] The RSRQ (Reference Signal Received Quality) is an indicator indicating a noise level with respect to the RSRP. That is, the RSRQ indicates a ratio of the signal strength and the noise level. The RSRQ is used to, for example, evaluate signal quality.

[0399] The RSSI (Received Signal Strength Indicator) is a value indicating the strength of a received signal. The RSSI is used to, for example, measure the strength of a signal of wireless communication. However, unlike the other indicators, the RSSI does not include information concerning the quality of a particular signal.

[0400] The SINR (Signal-to-Interference-plus-Noise Ratio) indicates a ratio of a signal and interference / noise.

[0401] The SNR (Signal-to-Noise Ratio) indicates a ratio of a signal and noise.

[0402] The SIR (Signal-to-Interference Ratio) indicates a ratio of a signal and interference. The SIR is used to evaluate the quality of communication.

[0403] The CSI (Channel State Information) is information indicating a state of a wireless propagation path. The CSI is used to grasp characteristics or quality of a communication path.

[0404] The CQI (Channel Quality Indicator) is an indicator indicating the quality of a wireless propagation path. The CQI corresponds to frequency utilization efficiency corresponding to a predetermined modulation scheme and the number of MIMO layers.

[0405] The PMI (Precoding Matrix Indicator) indicates a matrix for effectively transmitting signals between transmission antennas in MIMO (Multiple-Input Multiple-Output) communication.

[0406] The RI (Rank Indicator) indicates the number of MIMO layers (for example, the number of ranks, the number of transmit antennas, or available spatial multiplicity) in the MIMO communication.

[0407] (H3) Signal for measuring relative characteristics between communication points For example, the second DL signal may be a signal for measuring (or detecting, recognizing, surveying, or reporting) relative characteristics (for example, quality or characteristics) between communication points included in the common TCI state list.

[0408] Note that, as explained above, the UE may measure the communication quality of the respective communication points using the second DL signal. The UE may then report relative characteristics between the communication points in the initial access control.

[0409] The relative characteristics between the communication points may be differences (divergences / changes) in propagation characteristics between the communication points. For example, the relative characteristics between communication points (a difference in propagation characteristics between communication points) may be at least one of the following: ・ Difference concerning reception power (for example, at least one of RSRP, a path loss, and an SNR) between the communication points ・ Difference concerning a delay time (for example, at least one of an arrival time and delay dispersion) between the communication points ・ Difference concerning a Doppler Frequency between the communication points ・ Difference concerning a phase between communication points ・ Difference in the communication quality explained above between the communication points.

[0410] In the calculation of the relative characteristics between the communication points (for example, a difference in propagation characteristics between the communication points), a communication point serving as a reference may be set or specifies in advance. Alternatively, the UE may determine the communication point serving as the reference according to a predetermined reference. For example, the communication point serving as the reference may be any one of the following: ・ Communication point at which a value associated with the communication point (for example, a communication point ID (index)) is the minimum or the maximum ・ Communication point at which reception power is the maximum or the minimum ・ Communication point at which an arrival time is the earliest or the latest ・ Communication point at which communication quality for the communication point is the best or the worst ・ Communication point determined based on the second DL signal transmitted by the communication point (for example, a transmission resource of the second DL signal and / or an ID indicating the second DL signal) ・ Communication point set by control information included in the first DL channel

[0411] (H4) Synchronization signal For example, the second DL signal may be a signal having a function / a purpose / a configuration that are the same as or similar to those of CSI-RS(Channel State Information Reference Signals) and / or an SSS (Secondary Synchronization Signal) in the 5G.

[0412] Subsequently, the UE receives one or a plurality of second DL channels (step S105A, step S105B). At this time, the UE performs reception processing for one or a plurality of second DL channels assuming a TCI state of the second DL signal. That is, the UE performs the reception processing for the second DL channels using the second DL signal in the same TCI state (step S106). In the example illustrated in Fig. 22, the communication point P2and the communication point P3respectively transmit the second DL channels. These second DL channels can be multiplexed. For example, the second DL channels may be multiplexed in at least one of a time, a frequency, and a space (a code).

[0413] In the example illustrated in Fig. 22, the communication point P2and the communication point P3respectively transmit the second DL channels. However, a transmission mode of the second DL channels is not limited to this example. The UE only has to be assumed to be a QCL. For example, the second DL channels may be transmitted from a communication point different from the communication point P2and the communication point P3.

[0414] (Second DL channel) Here, the second DL channel (the second channel) may be a channel having a characteristic indicated by at least one of (I1) to (I6) explained below.

[0415] (I1)PDCCH and / or PDSCH For example, the second DL channel may be a PDCCH and / or a PDSCH.

[0416] (I2) DL channel transmitted from a communication point satisfying a standard For example, the second DL channel may be a DL channel transmitted from a communication point included in the common TCI state list.

[0417] (I3) DL channel capable of performing communication by the multilink connection For example, the second DL channel may be a DL channel capable of performing communication by the multilink connection.

[0418] (I4) DL channel in same TCI state as the second DL signal For example, the second DL channel may be a DL channel in the same TCI state as the received / detected second DL signal.

[0419] (I5) DL channel for transmitting report information For example, the second DL channel may be a DL channel for transmitting report information other than report information transmitted on the first DL channel.

[0420] (Example 1) For example, it is assumed that the report information transmitted on the first DL channel is an MIB. In this case, the second DL channel may be a DL channel for transmitting report information (for example, all SIBs) other than the MIB.

[0421] (Example 2) For example, it is assumed that the report information transmitted on the first DL channel is an MIB and an SIB1 (a first SIB). In this case, the second DL channel may be a channel for transmitting report information other than the MIB and the SIB1. For example, the second DL channel may be a channel for transmitting at least one of a plurality of SIBs following the SIB1 (the first SIB) (for example, a DL channel for transmitting all SIBs including a SIB2 and subsequent SIBs). In this case, the common TCI state list may be included in the SIB1.

[0422] (Example 3) For example, it is assumed that the report information transmitted on the first DL channel is an MIB, an MIB, and an SIB_n (an nth SIB). Here, n is an integer of 1 or more. In this case, the second DL channel may be a channel for transmitting report information other than the MIB and an SIB_n+1 (an n+1th SIB) (for example, all or some SIBs including the SIB_n+1 and subsequent SIBs). In this case, the common TCI state list may be included in the SIB_n. Then, the UE may perform reception processing for the second DL channel (a DL channel for transmitting all or some SIBs including the SIB_n+ 1 and subsequent SIBs) based on the common TCI state list included in the SIB_n.

[0423] Note that the order of the second DL signal and the second DL channel explained in the first example may be partially changed. For example, the UE may respectively receive the second DL signal and the second DL channel in the TCI state 2 and respectively receive the second DL signal and the second DL channel in the TCI state 3 in another time resource.

[0424] Note that some or all of the pieces of information concerning the common TCI state list (information concerning the second DL signal) explained in the first example may be set in the UE in advance (Pre-configuration). Examples of a method of setting the information in the UE in advance include a method in which a user of the UE manually sets the information in the UE, a method in which the UE is set at the time of manufacturing, and a method in which the information is set from a base station to which the UE was connected in the past.

[0425] Note that the signal / the channel (for example, at least one of the first DL signal, the first DL channel, the second DL signal and the second DL channel) explained in the first example may be always periodically transmitted or may be transmitted on demand. For example, the signal / the channel explained in the first example may be transmitted from a communication point on demand by a trigger signal from the network or the UE.

[0426] For example, the UE may transmit the trigger signal to a communication point (for example, some or all of the communication point P1to the communication point P3) specified based on the common TCI state list. Here, the trigger signal may be a signal for triggering transmission of the second DL signal and / or the second DL channel. When receiving the trigger signal, the communication point may start transmitting the second DL signal and / or the second DL channel. The trigger signal can be rephrased as trigger information, trigger channel, or wake-up signal.

[0427] According to the first example, the UE is capable of using the multilink connection from the stage of transmission and reception of the control information. That is, the multilink connection in the control plane is possible. As a result, wireless communication with high communication performance not depending on a location / an environment is implemented.

[0428] <5-4. Second example> Subsequently, an operation of the communication system 1 according to a second example is explained.

[0429] In the second example, the common TCI state list is transmitted in report information (for example, system information) and used for at least a part of the initial access control.

[0430] For example, in the second example, the communication point transmits the common TCI state list to the UE using the predetermined report information as in the first example. The predetermined notification information is, for example, an MIB and / or an SIB. The common TCI state list is used in at least a part of the initial access control. With the use method explained in the second example, the UE (the terminal device 40) is capable of performing communication (transmission or reception of a signal / information) by the multilink connection in at least a part of the initial access control.

[0431] Here, the initial access control that enables communication by the multilink connection is, for example, processing indicated by at least one of the following. In other words, the common TCI state list notified on the first DL channel and / or the second DL channel is used in processing indicated by at least one of the following: ・ Transmission processing and / or reception processing for the PRACH (the Msg1) ・ Transmission processing or reception processing for PDCCH and / or PDSCH including the random access response (the Msg2) ・ Transmission processing and / or reception processing for the PUSCH including the Msg3 ・ Transmission processing and / or reception processing for the PDCCH and the PDSCH for the contention resolution (the Msg4)

[0432] Fig. 23 is a sequence diagram illustrating communication processing according to the second example. In an example illustrated in Fig. 23, the communication processing is performed between one UE and a plurality of communication points (in the example illustrated in Fig. 23, the communication point P1to the communication point P3) that are respectively in different TCI states.

[0433] Note that processing of the communication point P (at least one of the communication point P1to the communication point P3) explained below may be performed by the communication point P itself or may be performed by a control device that controls the communication point P (for example, the control unit 23 of the base station 20 that controls the communication point P). The processing of the UE explained below may be performed by the control unit 43 of the UE (the terminal device 40).

[0434] In the second example as well, it is assumed that a plurality of communication points (in the example illustrated in Fig. 23, three communication points) respectively have TCI states different from a TCI state of other communication points. In the following explanation, as in the first example, a TCI state of the communication point P1is sometimes referred to as TCI state 1, a TCI state of the communication point P2is sometimes referred to as TCI state 2, and a TCI state of the communication point P3is sometimes referred to as TCI state 3.

[0435] In the following explanation, as in the first example, transmitting a signal / information on a predetermined channel is sometimes referred to as transmission of a channel and receiving the transmitted signal / information is sometimes referred to as reception of a channel. Here, the predetermined channel can be any channel.

[0436] In the following explanation, explanation of content that are the same as the content in the first example is sometimes omitted. The content explained in the first example can be applied to the first example as appropriate. Note that the first DL channel in the second example can be equivalent to the first DL channel (the first channel) explained in the first example. The second DL channel in the second example can be equivalent to the first DL channel (the first channel) explained in the first example. Alternatively, the second DL channel in the second example can be equivalent to the second DL channel (the second channel) explained in the first example. Note that a first UL channel and a third DL channel explained below can be respectively equivalent to the second channel (the QCL channel) of the first example.

[0437] Hereinafter, the communication processing according to the second example is explained with reference to the sequence diagram of Fig. 23.

[0438] First, the communication point P1transmits the first DL signal and the first / second DL channels (step S201). The UE receives the first DL signal and the first / second DL channels. Here, the UE may perform reception processing for the first / second DL channels based on a TCI state assumed based on the first DL signal (step S202). Then, the UE acquires information concerning the common TCI state list notified by the first / second DL channels (step S203). The information concerning the common TCI state list may be the common TCI state list itself.

[0439] Note that the information concerning the common TCI state list may include a parameter for setting information (a Quasi co-location relationship) concerning a QCL.

[0440] Here, the information concerning the QCL may include the second DL signal and information concerning a channel (hereinafter also referred to as QCL channel) assumed to be the QCL. Here, the QCL channel may be, for example, a PDSCH including a predetermined SIB and / or a PDCCH that schedules the PDSCH. Alternatively, the QCL channel may be, for example, a UL channel (PRACH) that transmits a random access preamble (the Msg1) or a DL channel (a PDCCH and / or a PDSCH) including a random access response (the Msg2). In the second example, for example, the first UL channel and the third DL channel explained below can be respectively equivalent to a QCL channel (the second channel in the first example). Note that the QCL channel may be specified in advance. In this case, the communication point may not transmit information concerning the QCL channel.

[0441] The information concerning the QCL may include information concerning a QCL type. At this time, the QCL type may be, for example, QCL type D. Note that the QCL type may be specified in advance. In that case, the communication point may not transmit information concerning the QCL type. In this case, the UE may perform reception processing / transmission processing (for example, processing concerning the multilink connection) of the QCL channel based on the QCL type (for example, the QCL type D) specified in advance and information concerning another QCL (for example, information concerning a QCL channel).

[0442] Besides, the information concerning the common TCI state list may be the same as the information concerning the common TCI state list explained in the first example.

[0443] The UE receives one or a plurality of second DL signals based on the common TCI state list (step S204A, step S204B). In the example illustrated in Fig. 23, the communication point P2and the communication point P3respectively transmit the second DL signals. These second DL signals can be multiplexed. For example, the second DL signals can be multiplexed in at least one of a time, a frequency, and a space (a code). In the example illustrated in Fig. 23, the second DL signals are respectively transmitted to the communication point P2and the communication point P3. However, a transmission mode of the second DL signals is not limited to this example. The UE only has to be assumed to be a QCL. For example, the second DL signals may be transmitted from a communication point different from the communication point P2and the communication point P3.

[0444] The UE transmits the one or a plurality of first uplink channels based on the common TCI state list and / or the second DL signal (step S205A, step S205B). In the following explanation, the first uplink channel is referred to as first UL channel. In the example illustrated in Fig. 23, the UE transmits the first UL channels respectively to the communication point P2and the communication point P3. These first UL channels can be multiplexed. For example, the first UL channels can be multiplexed in at least one of a time, a frequency, and a space (a code).

[0445] Note that, in the example illustrated in Fig. 23, the UE transmits the first UL channels respectively to the communication point P2and the communication point P3. However, a transmission mode of the first UL channels is not limited to this example. The UE only has to be assumed to be a QCL. For example, the UE may transmit the first UL channels to a communication point different from the communication point P2and / or the communication point P3.

[0446] Here, the first UL channel may be a channel having a characteristic indicated by at least one of (J1) to (J3) explained below.

[0447] (J1) PRACH For example, the first UL channel may be a PRACH.

[0448] (J2) UL channel for transmitting a preamble For example, the first UL channel may be a UL channel for transmitting a random access preamble (the Msg1).

[0449] (J3) UL channel containing a predetermined signal For example, the first UL channel may be a channel including a predetermined signal. Here, the predetermined signal is, for example, a signal (for example, a random access preamble) transmitted from the UE to a communication point for the purpose of initial access control, establishment of uplink synchronization, or acquisition of a specific ID for radio access communication. For example, the predetermined signal may be some or all of a plurality of types of predefined Zadoff-Chu sequences. Note that the predetermined signal can be selected at random from a predetermined selectable range by the UE. The predetermined selectable range can be specified / set based on, for example, the common TCI state list or information notified on the first / second DL channels.

[0450] As explained above, the UE transmits the one or plurality of first UL channels based on the common TCI state list. Here, the UE may transmit the first UL channel to each of the plurality of communication points or may transmit the first UL channel to one of the plurality of communication points.

[0451] (When transmitting to the plurality of communication points) The UE may transmit the first UL channel to all communication points included in the common TCI state list. The UE may transmit the first UL channel to some communication points included in the common TCI state list.

[0452] For example, the UE may transmit the random access preamble to a plurality of communication points respectively in different TCI states. At this time, the UE may transmit the same random access preamble to the plurality of communication points. Alternatively, the UE may transmit different random access preambles respectively to the plurality of communication points. The UE may transmit the random access preamble to the plurality of communication points using the same resources (for example, time and frequency resources). Alternatively, the UE may transmit the random access preamble to the plurality of communication points respectively using different resources (for example, time and frequency resources).

[0453] (When transmitting to one communication point) The UE may transmit the first UL channel to one communication point selected based on a predetermined standard. The predetermined standard may be a standard based on the common TCI state list. For example, the predetermined standard may be a standard based on reception power and / or reception timing of the detected / received second DL signal. The communication point can share information concerning the first UL channel (for example, information concerning the random access preamble) received from the UE with other communication points.

[0454] The UE receives one or a plurality of third downlink channels based on the common TCI state list and / or the second DL signal (step S206A, step S206B). In the following explanation, the third downlink channel is referred to as third DL channel. In the example illustrated in Fig. 23, the communication point P2and the communication point P3respectively transmit the third DL channels. These third DL channels may be multiplexed. For example, the third DL channels can be multiplexed in at least one of a time, a frequency, and a space (a code).

[0455] Note that, in the example illustrated in Fig. 23, the communication point P2and the communication point P3respectively transmit the third DL channels. However, a transmission mode of the third DL channels is not limited to this example. The UE only has to be assumed to be a QCL. For example, the third DL channels may be transmitted from a communication point different from the communication point P2and the communication point P3.

[0456] Here, the third DL channel may be a channel having a characteristic indicated by at least one of (K1) to (K4) explained below.

[0457] (K1) DL channel having the same characteristics as the characteristics of the second DL channel in the first example For example, the third DL channel may be a UL channel having the same characteristics as the characteristics of the second DL channel explained in the first example. The second DL channel in the first example may be, for example, a DL channel having a characteristic indicated by at least one of (I1) to (I6) explained above.

[0458] (K2) DL channel in a selected TCI state For example, it is assumed that, in step S205(step S205A and / or step S205B), the TCI state used for the transmission processing for the first UL channel (or the communication point serving as the transmission destination of the first UL channel) is selected based on the common TCI state list. In this case, the third DL channel may be a DL channel in the selected TCI state (or a TCI state of the selected communication point). For example, the third DL channel may be a DL channel capable of performing the reception processing in the TCI state. Note that, when a plurality of TCI states (or a plurality of communication points) are selected at step S205, the UE can receive a plurality of third DL channels. In this case, the plurality of third DL channels may be respectively DL channels capable of performing the reception processing in any one of the plurality of TCI states selected in step S205 (or a TCI state of any one of the selected plurality of communication points).

[0459] (K3) DL channel in a TCI state included in the common TCI state list For example, the third DL channel may be a DL channel in a TCI state included in the common TCI state list. For example, the third DL channel may be a DL channel capable of performing reception processing in any one of a plurality of TCI states included in the common TCI state list. At this time, the TCI state may not always be the TCI state of the communication point selected in step S205 explained above. That is, regardless of whether a TCI state (or a communication point) is selected in step S205 or regardless of which TCI state (or the communication point) is selected in step S205, the UE may set all the TCI states included in the common TCI state list as candidates of the TCI state used for the reception processing of the third DL channel.

[0460] (K4)DL channel including response information to the first UL channel For example, the third DL channel may be a DL channel including response information to a signal / information transmitted on the first UL channel. For example, the third DL channel may be a DL channel including a random access response (the Msg2) to the random access preamble (the Msg1) transmitted on the first UL channel.

[0461] Note that the response information (for example, the random access response) may include a TCI state list specific to the UE (a dedicated TCI state list). That is, the dedicated TCI state list can be set for the UE by reception of the third DL channel. When the dedicated TCI state list is not included in the response information, the UE may regard the common TCI state list acquired in step S203 as the dedicated TCI state list.

[0462] The response information (for example, the random access response) may include information concerning timing advance (transmission timing of the UL channel) in the corresponding TCI state (for example, the TCI state of the first UL channel).

[0463] After receiving the third DL channel, the UE transmits one or a plurality of second uplink channels (step S207A, step S207B). In the following explanation, the second uplink channel is referred to as second UL channel. In the example illustrated in Fig. 23, the UE transmits the second UL channels respectively to the communication point P2and the communication point P3. These second UL channels can be multiplexed. For example, the second UL channels can be multiplexed in at least one of a time, a frequency, and a space ( code).

[0464] Note that, in the example illustrated in Fig. 23, the UE transmits the second UL channels respectively to the communication point P2and the communication point P3. However, a transmission mode of the second UL channels is not limited to this example. The UE only has to be assumed to be a QCL. For example, the UE may transmit the second UL channels to a communication point different from communication point P2and / or communication point P3.

[0465] The second UL channel is, for example, a PUSCH. Here, the UE may transmit the second UL channel based on the dedicated TCI state list configured on the third DL channel. The second UL channel may include a message 3 (Msg3: Scheduled Transmission). When transmitting a plurality of second UL channels, the UE includes the message 3 in at least one of the plurality of second UL channels. For example, the UE may include the message 3 in the respective plurality of second UL channels or may include the message 3 in one of the plurality of second UL channels. The communication point can share information concerning the second UL channel (for example, information concerning the message 3) received from the UE with other communication points.

[0466] After transmitting the second UL channel, the UE transmits one or a plurality of fourth downlink channels (step S208A, step S208B). In the following explanation, the fourth downlink channel is referred to as fourth DL channel. In the example illustrated in Fig. 23, the communication point P2and the communication point P3respectively transmit the fourth DL channels. These fourth DL channels may be multiplexed. For example, the third DL channels can be multiplexed in at least one of a time, a frequency, and a space (a code).

[0467] In the example illustrated in Fig. 23, the communication point P2and the communication point P3respectively transmit the fourth DL channels. However, a transmission mode of the fourth DL channels is not limited to this example. The UE only has to be assumed to be a QCL. For example, the fourth DL channel may be transmitted from a communication point different from the communication point P2and the communication point P3.

[0468] The fourth DL channel is, for example, a PDCCH and / or a PDSCH. Here, the UE may receive the fourth UL channel based on the dedicated TCI state list set in the third DL channel. The fourth DL channel may include a message 4 (Msg4: Contention Resolution)). When a plurality of fourth DL channels are transmitted, the message 4 only has to be included in at least one of the plurality of fourth UL channels. For example, the plurality of fourth UL channels may respectively include the message 4 or one of the plurality of fourth UL channels may include the message 4.

[0469] Note that, in the first example, the four-step random access procedure is exemplified as the random access procedure. However, the random access procedure is not limited to the four-step random access procedure. For example, the random access procedure may be a two-step random access procedure.

[0470] In the two-step random access procedure, the UE simultaneously transmits the first UL channel and the second UL channel as the message A. A transmission method for the message A may be the same as the transmission method of the first UL channel and / or the second UL channel explained above. After transmitting the message A, the UE simultaneously receives the third DL channel and the fourth DL channel as the message B. A reception method for the message B may be the same as the reception method for the third DL channel and / or the fourth DL channel explained above.

[0471] In the first example, the TCI state list (the common TCI state list and / or the dedicated TCI state list) is common information in the downlink (DL) and the uplink (UL). However, the TCI state list may be different on the downlink and the uplink.

[0472] In the first example, the UE performs the DL communication and the UL communication with the plurality of communication points based on the TCI state list (the common TCI state list and / or the dedicated TCI state list). However, the communication with the plurality of communication points performed based on the TCI state list may be one of the DL communication and the UL communication. For example, the UE may perform the DL communication with a plurality of communication points based on the TCI state list and perform the DL communication with one communication point selected from the TCI state list.

[0473] According to the second example, the UE is capable of performing initial connection processing using the common TCI state list.

[0474] <5-5. Third example> Subsequently, an operation of the communication system 1 according to a third example is explained.

[0475] In the third example, the common TCI state list is used in fallback processing. For example, in the third example, the UE uses the common TCI state list (the default TCI state list) as a fallback TCI state list even when the specific TCI state list is set and / or even in the state of RRC_CONNECTED.

[0476] After performing fallback using the common TCI state list, the UE may acquire the dedicated TCI state list using radio connection subjected to the fallback. Then, the UE may perform multilink connection to a plurality of communication points using the dedicated TCI state list.

[0477] The common TCI state list in the third example is the same as a partial or the entire common TCI state list of the content explained in the other examples.

[0478] The UE may use the common TCI state list in processing indicated by at least one of (L1) to (L4) explained below even in a state in which the specific TCI state list is configured.

[0479] (L1) Reception of a predetermined PDCCH For example, the UE may use the common TCI state list in reception processing for a PDCCH transmitted in CORESET#0 (Control Resource Set #0) / search space #0.

[0480] (L2) Transmission / reception of a predetermined PUSCH / PDSCH For example, the UE may use the common TCI state list in transmission / reception processing for a PUSCH / a PDSCH scheduled in DCI0 _0 / 1_0. Note that one of the TCI states of the common TCI state list may be notified by the DCI.

[0481] (L3) Reception of a group common PDCCH For example, the UE may use the common TCI state list in reception processing for a group common PDCCH.

[0482] (L4) Communication in a default BWP For example, the UE may use the common TCI state list in the transmission / reception processing in a default BWP. At this time, the communication for which the common TCI state list is used may be limited to communication of a specific channel such as the PDCCH / the PDSCH / the PUCCH / the PUSCH / the PRACH.

[0483] The UE may use the common TCI state list when a predetermined condition is satisfied even in a state in which the specific TCI state list is set. For example, the UE may be connected (for example, reconnected) to one or a plurality of communication points using the common TCI state list when detecting a radio link failure (RLF). Here, the UE can detect the RLF based on, for example, a value measured based on the second DL signal of the common TCI state list.

[0484] A default TCI state list may be set in the UE of RRC_CONNECTED. The default TCI state list may be the common TCI state list.

[0485] Here, the default TCI state list may be a TCI state list having a characteristic indicated by at least one of (M1) to (M3) explained below.

[0486] (M1) Predetermined specific TCI state list For example, the default TCI state list may be a TCI state list determined by an ID of the specific TCI state list. For example, a specific TCI state list #0 may be the default TCI state list.

[0487] (M2) Common TCI state list For example, when the UE is not set by a dedicated RRC, the default TCI state list may be the common TCI state list (the initial TCI state list) itself.

[0488] (M3) TCI state list used in the default BWP For example, the default TCI state list may be a TCI state list used in the default BWP.

[0489] Note that, when a TCI state list other than the default TCI state list is active and a predetermined condition is satisfied (for example, when a timer starts and the timer expires), the UE may return the TCI state list to the default TCI state list.

[0490] According to the third example, the UE is capable of performing the fallback processing using the common TCI state list. Accordingly, the UE can recover the connection to the one or plurality of communication points early. As a result, wireless communication with high communication performance is implemented.

[0491] <5-6. Fourth example> Subsequently, an operation of the communication system 1 according to a fourth example is explained.

[0492] In the embodiment explained above, the common TCI state list is the TCI state list used in common in all UEs that communicate with a predetermined communication point. However, a use target of the common TCI state list is not limited to all the UEs that communicate with the predetermined communication point. For example, the common TCI state list may be a TCI state list used in common by two or more UEs among a plurality of UEs that communicate with the predetermined communication point (that is, a plurality of UEs satisfying a predetermined standard among all the UEs that communicate with the predetermined communication point). That is, the common TCI state list may be a TCI state list (common information) common to a UE group (also referred to as terminal device group) including a plurality of terminal devices 40.

[0493] In the following explanation, this common TCI state list is referred to as UE group common TCI state list (UE-group Common TCI state list). The UE group common TCI state list can be rephrased as group common TCI state list.

[0494] The UE group common TCI state list is explained below. Note that content explained in the fourth example may be combined with the content explained in the embodiment (for example, the first example to the third example). In this case, the description of the "common TCI state list" appearing in the embodiment explained above can be replaced with "UE group common TCI state list" as appropriate. Besides, the content explained in the embodiment explained above can be applied to the communication system 1 (for example, the communication point and / or the UE) in the fourth example as appropriate.

[0495] Hereinafter, differences from the embodiment explained above (for example, the first example to the third example) are mainly explained.

[0496] The UE group common TCI state list may include at least a part of information explained below in addition to or instead of the information included in the common TCI state list explained in the embodiment explained above (for example, the first example to the third example).

[0497] For example, the UE group common TCI state list may include information concerning a UE to which the UE group common TCI state list is applied (that is, a UE for which the UE group common TCI state list is valid / active among the plurality of UEs). The UE to which the UE group common TCI state list is applied is, for example, a UE that satisfies a predetermined standard among all UEs that communicate with a predetermined communication point, that is, a UE belonging to a predetermined UE group. In the following explanation, the UE to which the UE group common TCI state list is applied is referred to "application target UEs".

[0498] Here, the UE group common TCI state list may include, as information concerning the application target UE, information indicated by at least one of (N1) to (N3) explained below.

[0499] (N1) Identification information of the UE For example, the UE group common TCI state list may include, as the information concerning the application target UE, identification information (UE-ID) for designating the application target UE.

[0500] (N2) Information concerning a state of a UE For example, the UE group common TCI state list may include, as the information concerning the application target UE, information indicating information concerning a state of a UE. For example, the UE group common TCI state list may include, as the information concerning the application target UE, information indicated by at least one of the following.

[0501] (Information concerning a connection state of the UE) For example, the information concerning the state of the UE may be information concerning a connection state of the UE. For example, the information concerning the state of the UE may be information indicating at least one of UE_CONNECTED (for example, RRC_CONNECTED), UE_IDLE (for example, RRC_IDLE), and UE_INACTIVE (for example, RRC_INACTIVE).

[0502] (Information that can be acquired by a sensor of the UE) For example, the information concerning the state of the UE may be information that can be acquired by a sensor of the UE (for example, the sensor unit 44 of the terminal device 40). For example, the information concerning the state of the UE may be at least one of location (for example, altitude), moving speed, inclination, vibration, rotation, and temperature. For example, when a value acquired by the sensor of the UE is included in a range indicated by the information concerning the state of the UE (for example, when altitude measured by the sensor is included in an altitude range indicated by the information concerning the state of the UE), the UE may discriminate that the UE corresponds to the application target UE.

[0503] (Information indicating a geographic location) For example, the information concerning the state of the UE may be information indicating a geographical location. For example, the information concerning the state of the UE may be a location (for example, information indicating at least one of latitude, longitude, and area) of the UE. For example, the information concerning the state of the UE may be a range the altitude of the UE that is the application target UE. For example, when the location of the UE is included in the range indicated by the information concerning the state of the UE (for example, when the location of the UE is included in an area indicated by the information concerning the state of the UE), the UE may discriminate that the UE corresponds to the application target UE.

[0504] The UE may discriminate whether the UE corresponds to the application target UE based on the information concerning the application target UE. Note that, when information concerning a plurality of application target UEs is included in the UE group common TCI state list, the UE may discriminate that the UE corresponds to the application target UE when the UE corresponds to at least one of the plurality of pieces of information. Alternatively, when the UE corresponds to all of the plurality of pieces of information, the UE may discriminate that the UE corresponds to the application target UE.

[0505] When the UE corresponds to the applicable UE, the UE may apply the UE group common TCI state list. That is, the UE may perform reception processing / transmission processing based on a TCI state included in the UE group common TCI state list.

[0506] According to the fourth example, it is possible to set the common TCI state list in units of UE groups. That is, a TCI state list that is more matching the UE is set in the UE compared with when a common TCI state list is set in all the UEs. For that reason, the UE is capable of performing highly accurate transmission processing / reception processing based on the common TCI state list. As a result, wireless communication with high communication performance is implemented.

[0507] <<6. Modifications>> The embodiment explained above indicates an example. Various changes and applications of the embodiment are possible.

[0508] For example, in the embodiment explained above (for example, the first example to the fourth example), the common TCI state list is the information used for the processing concerning the multilink connection. However, the common TCI state list may be used for communication processing other than the processing concerning the multilink connection. For example, the terminal device 40 may perform processing concerning connection to one second communication point (for example, the communication point P2or the communication point P3) based on the common TCI state list. As a result, the terminal device 40 is capable of performing communication processing (for example, transmission processing and / or reception processing) based on a TCI state of the second communication point from a stage of transmission and reception of control information. As a result, wireless communication with high communication performance is implemented.

[0509] The multilink connection in the present embodiment may be connection by a carrier aggregation technology, a dual connectivity technology, or a multi-connectivity technology. The multilink connection in the present embodiment may be connection by a coordinated transmission and reception (Coordinated Multi-Point Transmission and Reception) technology. Besides, the multilink connection may be connection at the time when the terminal device 40 is simultaneously connected to a plurality of communication points to perform communication (for example, transmission and / or reception of control information).

[0510] The functions of the base station 20 in the present embodiment may be separated into a plurality of functions such as a CU (Central Unit), a DU (Distributed Unit), and an RU (Radio Unit). In this case, the description of the base station 20 (or the BS) explained above can be replaced with CU, DU, or RU.

[0511] The control device that controls the management device 10, the base station 20, the relay station 30, or the terminal device 40 in the present embodiment may be implemented by a dedicated computer system or may be implemented by a general-purpose computer system.

[0512] For example, a program for executing the operation explained above is stored in a computer-readable recording medium such as an optical disk, a semiconductor memory, a magnetic tape, or a flexible disk and distributed. Then, for example, the program is installed in a computer and the control device is configured by executing the processing explained above. At this time, the control device may be a device (for example, a personal computer) on the outside of the management device 10, the base station 20, the relay station 30, or the terminal device 40. The control device may be a device (for example, the control unit 13, the control unit 23, the control unit 33, or the control unit 43) on the inside of the management device 10, the base station 20, the relay station 30, or the terminal device 40.

[0513] The communication program explained above may be stored in a disk device included in a server device on a network such as the Internet to make it possible to download the communication program to a computer. The functions explained above may be implemented by cooperation of an OS (Operating System) and application software. In this case, a portion other than the OS may be stored in a medium and distributed or the portion other than the OS may be stored in the server device to make it possible to, for example, download the portion to the computer.

[0514] Among the kinds of processing explained in the embodiment, all or a part of the processing explained as being automatically performed can be manually performed or all or a part of the processing explained as being manually performed can be automatically performed by a publicly-known method. Besides, the processing procedures, the specific names, and the information including the various data and parameters explained in the document and illustrated in the drawings can be optionally changed except when specifically noted otherwise. For example, the various kinds of information illustrated in the figures are not limited to the illustrated information.

[0515] The illustrated components of the devices are functionally conceptual and are not always required to be physically configured as illustrated in the figures. That is, specific forms of distribution and integration of the devices are not limited to the illustrated forms and all or a part thereof can be functionally or physically distributed and integrated in any unit according to various loads, usage situations, and the like.

[0516] The embodiments explained above can be combined as appropriate in a region in which the processing content do not contradict. The order of the steps illustrated in the sequence chart or the flowchart in the present embodiment can be changed as appropriate.

[0517] For example, the present embodiment can be implemented as any configuration configuring a device or a system, for example, a processor functioning as a system LSI (Large Scale Integration) or the like, a module using a plurality of processors or the like, a unit using a plurality of modules or the like, a set obtained by further adding other functions to the unit, and the like (that is, a configuration of a part of the device).

[0518] The functions implemented by the components described in the present specification may be implemented in a circuitry or a processing circuitry programmed to implement the described functions. Here, the circuitry or the processing circuitry may be a general-purpose processor, a specific use processor, an integrated circuit, ASICs (Application Specific Integrated Circuits), a CPU (a Central Processing Unit), a conventional circuit, and / or a combination thereof. The processor includes a transistor and other circuits. The processor may be regarded as a circuitry or a processing circuitry. The processor may be a programmed processor that executes a program stored in a memory.

[0519] In the present specification, a circuitry, a unit, and means may be hardware programmed to implement the described functions or hardware that executes the described functions. The hardware may be any hardware disclosed in the present specification or any hardware programmed to implement or known to execute the described functions. When the hardware is a processor regarded as a type of a circuitry, the circuitry, means, or a unit may be a combination of hardware and software used to configure the hardware and / or the processor.

[0520] Furthermore, for example, the present embodiment can be implemented as all components configuring a device or a system. For example, the present embodiment can be implemented as a processor as a system LSI (Large Scale Integration) or the like, a module using a plurality of processors or the like, a unit using a plurality of modules and the like, or a set in which other functions are further added to the unit. That is, the present embodiment can be implemented as a part of the configuration of the device.

[0521] The system LSI may be called SOC (System on Chip). In other words, each of the devices explained above or explained below (for example, the management device 10, the base station 20, the relay station 30, and the terminal device 40) may be interpreted as a processor (for example, a CPU) serving as a system LSI (for example, SoC) or a module that uses or configures the processor. Further or alternatively, the present embodiment may be implemented by all components (for example, a modem chip (a baseband chip) or an RF (Radio Frequency) unit or a combination thereof) configuring the device or the system. The RF unit may include at least one of an RF circuit and an RF front-end. In other words, each of the devices explained above or explained below may be interpreted as a modem chip (a baseband chip) or an RF unit or a combination thereof. Further or alternatively, each of the devices explained above or explained below may be interpreted as a module using or configuring the modem chip or the RF unit.

[0522] The modem chip performs signal processing concerning communication in the device (including the device explained above or explained below). The modem chip may have a function of at least a modulator or a demodulator. The RF unit may have a function of at least one of an RF transceiver (for example, an RF Upconverter and / or an RF Downconverter), a power amplifier, and a low noise amplifier. The RF transceiver converts a baseband signal and an RF frequency. The power amplifier performs amplification for transmitting a signal from an antenna. The low noise amplifier amplifies a very weak signal received from the antenna. Further or alternatively, the RF unit (in particular, the RF front-end) may include at least one of the power amplifier explained above, a low noise amplifier, ab envelope tracker, a filter, a duplexer, a multiplexer, an antenna switch, and an antenna tuner.

[0523] A combination of the modem chip and the RF unit may be referred to as modem-RF system. At least a part of the modem chip or the RF unit or the combination thereof may be included in a system LSI (for example, SoC). For example, processing (for example, processing of at least a part of MAC layer processing / PHY layer processing) performed by at least a part of the modem chip or the RF unit or the combination thereof may be implemented by a system LSI. Here, the MAC layer processing or the PHY layer processing may be processing of at least a part of processing executed by the device (for example, the management device 10, the base station 20, the relay station 30, and the terminal device 40) in the embodiment explained above or explained below.

[0524] Note that, in the present embodiments, the system means a set of a plurality of components (devices, modules (components), and the like) It does not matter whether all the components are present in the same housing. For example, both of a plurality of devices housed in separate housings and connected via a network or the like and one device in which a plurality of modules are housed in one housing are systems.

[0525] For example, the present embodiment can adopt a configuration of cloud computing in which one function is shared and processed by a plurality of devices in cooperation via a network.

[0526] <<7. Conclusion>> According to the present embodiment, the communication device (for example, the base station 20) included in the communication system 1 acquires information (a TCI state list) concerning a TCI state of one or a plurality of communication points. Then, the communication device (for example, the base station 20) transmits the information concerning the TCI state to the plurality of terminal devices 40 as common information. That is, the communication device (for example, the base station 20) transmits a common TCI state list to the terminal device 40.

[0527] The terminal device 40 receives the information (the common TCI state list) concerning the TCI state transmitted as the common information. Then, the terminal device 40 performs processing concerning communication based on the information (the common TCI state list) concerning the TCI state transmitted as the common information. For example, the terminal device 40 performs processing concerning multilink connection to a plurality of communication points based on the common TCI state list.

[0528] Accordingly, the terminal device 40 is capable of using the multilink connection from a stage of transmission and reception of control information. That is, the multilink connection in the control plane is possible. As a result, wireless communication with high communication performance not depending on a location / an environment is implemented.

[0529] Although the embodiments of the present disclosure are explained above, the technical scope of the present disclosure is not limited to the embodiments per se. Various changes can be made without departing from the gist of the present disclosure. Components in different embodiments and modifications may be combined as appropriate.

[0530] The effects in the embodiments described in this specification are only illustrations and are not limited. Other effects may be present.

[0531] Note that the present technology can also take the following configurations. (1) A terminal device, comprising: processing circuitry configured to receive a first downlink signal and a first downlink channel from a first communication point, wherein the first downlink channel includes system information, acquire information concerning a common Transmission Configuration Indicator (TCI) state list from the system information, wherein the common TCI state list includes TCI states of a plurality of second communication points and is transmitted as common information to a plurality of terminal devices, receive one or more second downlink signals based on the common TCI state list from at least one of the plurality of second communication points, and perform reception processing for one or more second downlink channels based on the TCI states included in the common TCI state list. (2) The terminal device according to (1), wherein the system information is at least one of a Master Information Block (MIB) transmitted on a Physical Broadcast Channel (PBCH) and a System Information Block (SIB) transmitted on a Physical Downlink Shared Channel (PDSCH). (3) The terminal device according to (1), wherein the processing circuitry is further configured to perform reception processing for the first downlink channel based on a TCI state assumed from the first downlink signal. (4) The terminal device according to (1), wherein the common TCI state list includes information concerning Quasi-Co-Location (QCL) relationships for enabling multilink connection between the terminal device and the plurality of second communication points. (5) The terminal device according to (1), wherein the processing circuitry is further configured to transmit a random access preamble to at least one of the plurality of second communication points based on the common TCI state list during initial access procedure. (6) The terminal device according to (5), wherein the processing circuitry is further configured to receive a random access response from at least one of the plurality of second communication points in a TCI state included in the common TCI state list, and transition from an RRC_IDLE state to an RRC_CONNECTED state upon successful completion of the initial access procedure. (7) The terminal device according to (1), wherein the second downlink signals are reference signals for measuring communication quality of the plurality of second communication points included in the common TCI state list. (8) The terminal device according to (1), wherein the processing circuitry is further configured to establish multilink connection with at least two of the plurality of second communication points for control-plane communication based on different TCI states in the common TCI state list. (9) The terminal device according to (1), wherein the processing circuitry is further configured to determine at least a part of transmission resources of the second downlink signals based on transmission resources of the first downlink signal received from the first communication point. (10) An infrastructure equipment, comprising: processing circuitry configured to acquire information concerning TCI states of a plurality of communication points; generate a common TCI state list including the TCI states of the plurality of communication points, wherein the common TCI state list is configured to be used by a plurality of terminal devices for multilink connection, transmit system information including the common TCI state list as common information via a broadcast channel, and control transmission of downlink signals and downlink channels from the plurality of communication points according to the TCI states in the common TCI state list. (11) The infrastructure equipment according to (10), wherein the system information is transmitted in at least one of a Master Information Block (MIB) on a Physical Broadcast Channel (PBCH) and a System Information Block (SIB) on a Physical Downlink Shared Channel (PDSCH). (12) The infrastructure equipment according to (10), wherein the common TCI state list includes an identifier for each TCI state, transmission resource information for signals corresponding to each TCI state, and QCL type information indicating spatial parameters. (13) The infrastructure equipment according to (10), wherein the processing circuitry is further configured to receive a random access preamble from a terminal device, and transmit a random access response including a dedicated TCI state list specific to the terminal device. (14) The infrastructure equipment according to (10), wherein the plurality of communication points include at least one of transmission reception points (TRPs), small cells using high-frequency bands, and beam cells formed by beamforming. (15) The infrastructure equipment according to (10), wherein the processing circuitry is further configured to dynamically or quasi-statically update the common TCI state list. (16) The infrastructure equipment according to (10), wherein the common TCI state list enables control-plane communication with the plurality of communication points during initial access procedures. (17) A communication method performed by a terminal device, comprising: receiving system information via a broadcast channel from a communication point, wherein the system information includes a common TCI state list transmitted as common information to a plurality of terminal devices; identifying TCI states of a plurality of communication points from the common TCI state list; performing initial access procedure using the common TCI state list, including transmitting a random access preamble based on at least one TCI state in the common TCI state list; and establishing multilink connection with the plurality of communication points for control-plane communication based on the common TCI state list. (18) The communication method according to (17), wherein the system information is received in at least one of a Master Information Block (MIB) transmitted on a Physical Broadcast Channel (PBCH), and a System Information Block (SIB) transmitted on a Physical Downlink Shared Channel (PDSCH) scheduled by a Physical Downlink Control Channel (PDCCH). (19) The communication method according to (17), further comprising: receiving a random access response including a dedicated TCI state list; and transitioning from using the common TCI state list to using the dedicated TCI state list for subsequent communication. (20) The communication method according to (17), further comprising: using the common TCI state list as a fallback option when a radio link failure is detected in RRC_CONNECTED state; and re-establishing connection to at least one communication point using the common TCI state list.

[0532] 1 Communication system 10 Management device 20 Base station 30 Relay station 40 Terminal device 11 Communication unit 21, 31, 41 Wireless communication unit 12, 22, 32, 42 Storage unit 13, 23, 33, 43 Control unit 44 Sensor unit 211, 311, 411 Transmission processing unit 212, 312, 412 Reception processing unit 213, 313, 413 Antenna 231, 331, 431 Acquisition unit 232, 332, 432 Transmission control unit 233, 333, 433 Reception control unit 234, 334, 434 Communication control unit P Communication point

Claims

1. A terminal device, comprising: 　　processing circuitry configured to 　　receive a first downlink signal and a first downlink channel from a first communication point, wherein the first downlink channel includes system information, 　　acquire information concerning a common Transmission Configuration Indicator (TCI) state list from the system information, wherein the common TCI state list includes TCI states of a plurality of second communication points and is transmitted as common information to a plurality of terminal devices, 　　receive one or more second downlink signals based on the common TCI state list from at least one of the plurality of second communication points, and 　　perform reception processing for one or more second downlink channels based on the TCI states included in the common TCI state list.

2. The terminal device of claim 1, wherein the system information is at least one of a Master Information Block (MIB) transmitted on a Physical Broadcast Channel (PBCH) and a System Information Block (SIB) transmitted on a Physical Downlink Shared Channel (PDSCH).

3. The terminal device of claim 1, wherein the processing circuitry is further configured to 　　perform reception processing for the first downlink channel based on a TCI state assumed from the first downlink signal.

4. The terminal device of claim 1, wherein the common TCI state list includes information concerning Quasi-Co-Location (QCL) relationships for enabling multilink connection between the terminal device and the plurality of second communication points.

5. The terminal device of claim 1, wherein the processing circuitry is further configured to 　　transmit a random access preamble to at least one of the plurality of second communication points based on the common TCI state list during initial access procedure.

6. The terminal device of claim 5, wherein the processing circuitry is further configured to 　　receive a random access response from at least one of the plurality of second communication points in a TCI state included in the common TCI state list, and 　　transition from an RRC_IDLE state to an RRC_CONNECTED state upon successful completion of the initial access procedure.

7. The terminal device of claim 1, wherein the second downlink signals are reference signals for measuring communication quality of the plurality of second communication points included in the common TCI state list.

8. The terminal device of claim 1, wherein the processing circuitry is further configured to 　　establish multilink connection with at least two of the plurality of second communication points for control-plane communication based on different TCI states in the common TCI state list.

9. The terminal device of claim 1, wherein the processing circuitry is further configured to 　　determine at least a part of transmission resources of the second downlink signals based on transmission resources of the first downlink signal received from the first communication point.

10. An infrastructure equipment, comprising: 　　processing circuitry configured to 　　acquire information concerning TCI states of a plurality of communication points; generate a common TCI state list including the TCI states of the plurality of communication points, wherein the common TCI state list is configured to be used by a plurality of terminal devices for multilink connection, 　　transmit system information including the common TCI state list as common information via a broadcast channel, and 　　control transmission of downlink signals and downlink channels from the plurality of communication points according to the TCI states in the common TCI state list.

11. The infrastructure equipment of claim 10, wherein the system information is transmitted in at least one of a Master Information Block (MIB) on a Physical Broadcast Channel (PBCH) and a System Information Block (SIB) on a Physical Downlink Shared Channel (PDSCH).

12. The infrastructure equipment of claim 10, wherein the common TCI state list includes an identifier for each TCI state, transmission resource information for signals corresponding to each TCI state, and QCL type information indicating spatial parameters.

13. The infrastructure equipment of claim 10, wherein the processing circuitry is further configured to 　　receive a random access preamble from a terminal device, and 　　transmit a random access response including a dedicated TCI state list specific to the terminal device.

14. The infrastructure equipment of claim 10, wherein the plurality of communication points include at least one of transmission reception points (TRPs), small cells using high-frequency bands, and beam cells formed by beamforming.

15. The infrastructure equipment of claim 10, wherein the processing circuitry is further configured to 　　dynamically or quasi-statically update the common TCI state list.

16. The infrastructure equipment of claim 10, wherein the common TCI state list enables control-plane communication with the plurality of communication points during initial access procedures.

17. A communication method performed by a terminal device, comprising: 　　receiving system information via a broadcast channel from a communication point, wherein the system information includes a common TCI state list transmitted as common information to a plurality of terminal devices; 　　identifying TCI states of a plurality of communication points from the common TCI state list; 　　performing initial access procedure using the common TCI state list, including transmitting a random access preamble based on at least one TCI state in the common TCI state list; and 　　establishing multilink connection with the plurality of communication points for control-plane communication based on the common TCI state list.

18. The communication method of claim 17, wherein the system information is received in at least one of a Master Information Block (MIB) transmitted on a Physical Broadcast Channel (PBCH), and a System Information Block (SIB) transmitted on a Physical Downlink Shared Channel (PDSCH) scheduled by a Physical Downlink Control Channel (PDCCH).

19. The communication method of claim 17, further comprising: receiving a random access response including a dedicated TCI state list; and 　　transitioning from using the common TCI state list to using the dedicated TCI state list for subsequent communication.

20. The communication method of claim 17, further comprising: 　　using the common TCI state list as a fallback option when a radio link failure is detected in RRC_CONNECTED state; and 　　re-establishing connection to at least one communication point using the common TCI state list.

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