Communication device, communication method, and communication system

Abstract

This communication device comprises: a transmission control unit that repeatedly performs, in a second cycle longer than a first cycle, a plurality of transmissions of an initial access signal in the first cycle, the initial access signal being for a terminal device to make an initial access to a wireless network and including a synchronization signal and notification information; and a reception control unit that receives an uplink signal for the initial access.

Description

Communication Apparatus, Communication Method, and Communication System

[0001] The present disclosure relates to a communication apparatus, a communication method, and a communication system.

[0002] Technologies related to wireless communication such as cellular communication are being actively developed. In recent years, the communication performance is improved by arranging a large number of communication nodes (e.g., base stations and / or antennas) accessed by terminal devices in a communication environment, or by arranging various communication nodes in the communication environment. Studies on technologies for such improvement have been started. For example, in recent years, studies on cell-free networks that abandon the conventional cell concept have been initiated.

[0003] 3GPP, R1-166653, "Consideration on synchronization for NR," 3GPP TSG RAN WG1 Meeting #86, Sony, August 2016

[0004] However, simply arranging a large number of or various communication nodes in a communication environment does not necessarily realize wireless communication with high communication performance (e.g., high resource utilization efficiency, large capacity, high speed, low latency, high reliability, high density, large number of simultaneous connections, power saving, low interference, or low processing load). For example, in an environment where there are a large number of or various communication nodes, the increase in the number of communication nodes leads to increased power consumption due to the increase in control signals, or exacerbates the problem of radio interference, and as a result, wireless communication with high communication performance may not be achieved.

[0005] Therefore, the present disclosure proposes a communication apparatus, a communication method, and a communication system that can achieve high communication performance.

[0006] It should be noted that the above problem or objective is merely one of a plurality of problems or objectives that can be solved or achieved by the plurality of embodiments disclosed in the present specification.

[0007] To solve the above problems, one form of communication device according to the present disclosure includes a transmission control unit that repeatedly transmits an initial access signal, which includes a synchronization signal and broadcast information, multiple times in a first cycle for a terminal device to initially access a wireless network, in a second cycle that is longer than the first cycle, and a reception control unit that receives the uplink signal for the initial access.

[0008] This is a diagram illustrating the outline of an embodiment. This is a diagram illustrating an example of the configuration of a communication system according to an embodiment. This is a diagram illustrating the configuration of a management device according to an embodiment. This is a diagram illustrating the configuration of a base station according to an embodiment. This is a diagram illustrating the configuration of a terminal device according to an embodiment. This is a diagram illustrating an example of a communication system according to an embodiment. This is a diagram illustrating standalone operation. This is a diagram illustrating standalone operation. This is a sequence diagram showing an example of initial access processing. This is a diagram illustrating a collision-based random access procedure. This is a diagram illustrating a non-collision-based random access procedure. This is a diagram illustrating a two-step random access procedure. This is a diagram illustrating conventional synchronization processing. This is a diagram illustrating the operation of a communication point. This is a diagram illustrating how multiple transmissions of the initial access signal are performed in succession. This is a diagram illustrating an example of the signal configuration of an SSB. This is a diagram illustrating another example of the signal configuration of an SSB. This is a diagram illustrating an example of the signal configuration of an initial access signal according to an embodiment. This is a diagram illustrating another example of the signal configuration of an initial access signal according to an embodiment. This is a diagram illustrating another example of the signal configuration of an initial access signal according to an embodiment. This is a diagram illustrating another example of the signal configuration of an initial access signal according to an embodiment. This is a diagram illustrating another example of the signal configuration of an initial access signal according to an embodiment. This is a diagram illustrating an example of the signal configuration of an initial access signal according to a first embodiment. This is a sequence diagram showing communication processing according to a first embodiment. This figure shows an example of the signal configuration of the initial access signal according to the second embodiment. This figure shows another example of the signal configuration of the initial access signal according to the second embodiment. This is a sequence diagram showing the communication process according to the second embodiment. This is a sequence diagram showing the communication process according to the third embodiment.

[0009] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the following embodiments, the same parts will be denoted by the same reference numerals to avoid redundant descriptions.

[0010] Furthermore, in this specification, the expression "at least one of" accompanied by an enumeration of elements is understood to mean that the enumerated elements are the choices. For example, "at least one of A, B, and C" means "(A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C)." "at least one of A, B, or C" and "at least one of A, B, and / or C" are similar to "at least one of A, B, and C." Here, A, B, and C are all arbitrary expressions (e.g., word, phrase, clause, term, or item).

[0011] Furthermore, in this specification and drawings, multiple components having substantially the same functional configuration may be distinguished by adding different numbers after the same reference numeral. For example, multiple components having substantially the same functional configuration may be distinguished as communication point P as needed. １ , P ２ , and P ３ They are distinguished in this way. However, if there is no need to particularly distinguish each of multiple components that have substantially the same functional configuration, only the same code is assigned. For example, communication point P １ , P ２ , and P ３ When there is no particular need to distinguish between them, they are simply referred to as communication point P.

[0012] The one or more embodiments (including examples and modifications) described below can each be implemented independently. On the other hand, at least some of the embodiments described below may be implemented in appropriate combination with at least some of the other embodiments. These embodiments may contain novel features that differ from each other. Therefore, these embodiments may contribute to solving different objectives or problems and may produce different effects.

[0013] This disclosure will be explained in the following order of items: 1. Overview 1-1. Background and Issues 1-2. Details of Issues 1-3. Overview of Solutions 2. Communication System Configuration 2-1. Example of Management Device Configuration 2-2. Example of Base Station Configuration 2-3. Example of Terminal Device Configuration 3. Underlying Technologies 3-1. Communication Points 3-1-1. Definition of Communication Points 3-1-2. Specific Examples of Communication Systems 3-1-3. Others 3-2. Initial Access Control 3-2-1. Basic Procedure 3-2-2. Random Access Procedure 3-2-3. Random Access Procedure for NR 3-2-4. Initial Access Control in Self-Free Communication 3-3. Conventional Synchronization Processing 3-4. Supplementary Information 4. Operation of the Communication System 4-1. Explanation of Terms 4-2. Overview of Operation 4-3. Operation of Communication Points 4-3-1. 4-3-2. Basic Operation of the Communication Point 4-3-3. Transmission Cycle 4-3-4. State of the Communication Point 4-3-5. Configuration of the SSB Group 4-3-6. Functions of the Communication Point 4-3-7. Information Included in the Initial Access Signal 4-4. Others 4-4. Signal Configuration of the Initial Access Signal 4-4-1. Signal Configuration Example 1 4-4-2. Signal Configuration Example 2 4-4-3. Signal Configuration Example 3 4-4-4. Signal Configuration Example 4 4-4-5. Signal Configuration Example 5 4-5. Communication Processing 4-5-1. First Embodiment (Power Saving Use Case) 4-5-2. Second Embodiment (Low Latency Use Case) 4-5-3. Third Embodiment (Composite Use Case) 5. Modifications 6. Conclusion

[0014] <<1. Overview>> First, the overview of this embodiment will be explained.

[0015] <1-1. Background and Challenges> Development of wireless communication technologies such as cellular communication is actively underway. Currently, 3GPP (registered trademark) is beginning discussions toward B5G (Beyond 5G) and 6G (6th Generation Mobile Communication System) in parallel with the formulation of 5G (5th Generation) specifications.

[0016] Conventional cellular communications have controlled communication in units of a single base station (including a TRP (Transmission and Reception Point)) called a cell, which is the communication range (communication coverage). However, with B5G and 6G, systems are expected to operate in high-frequency bands such as terahertz waves in addition to millimeter waves. Communication using high-frequency bands has a shorter propagation distance compared to communication using low-frequency bands. Therefore, it is expected that the communication range (communication coverage) of base stations will be smaller than before in B5G and 6G.

[0017] Furthermore, future wireless communications are expected to feature a greater diversity of communication nodes. For example, in 5G, in addition to base stations, it is anticipated that overhanging antennas called TRPs will be used as communication nodes. Moreover, it is anticipated that IAB (Integrated Access and Backhaul) nodes (i.e., base station relays) will be used as communication nodes in 5G. Additionally, it is anticipated that NTN (Non-terrestrial network) nodes (e.g., communication satellites) will be used as communication nodes in 5G.

[0018] In B5G and 6G, further diversification of communication nodes is expected to be pursued with the aim of supporting high frequency bands and / or reducing CAPEX / OPEX. For example, in B5G and 6G, smart repeaters (e.g., RIS (Reconfigurable Intelligent Surface)) are expected to be used as communication nodes. In addition, terminal-to-terminal relays are also expected to be used in B5G and 6G. Conventional communication nodes were either fully controllable communication nodes (e.g., base stations and / or IAB nodes) or communication nodes that could not be controlled at all (e.g., RF (Radio Frequency) repeaters). However, in the future, it is expected that communication nodes with controllable parameters will also be used.

[0019] To deploy a communication area across a wide area using communication nodes with narrowed communication coverage, an extremely large number of communication nodes are required. Therefore, it is expected that conventional cell design will become very difficult. Furthermore, the diversification of communication nodes will also increase the difficulty of cell design. For this reason, it is expected that cell-free networks will be introduced as a basic function in B5G and 6G. A cell-free network is a wireless network that eliminates cell boundaries in a conventional cell configuration (cellular network) centered on a base station. A cell-free network realizes an optimal communication environment that does not depend on the positional relationship between the user and the base station. The realization of a cell-free network will enable more efficient network operation. In addition, the realization of a cell-free network will enable the efficient provision of information on a user-by-user basis.

[0020] In a self-free network, coordination between base stations becomes a topic of discussion. As mentioned above, in an environment with diverse types and / or frequencies of communication nodes, an increase in power consumption is expected due to the increase in the number of communication nodes. Therefore, it is anticipated that there will be a growing demand for operating each communication node with lower power consumption. Furthermore, in an environment with diverse types and / or frequencies of communication nodes, an increase in the number of communication nodes is expected to exacerbate radio interference problems. Therefore, it is anticipated that there will be a growing demand for methods to reduce radio interference.

[0021] The current 5G (NR) standard employs SSB (SS / PBCH block) for transmitting synchronization signals and broadcast information for initial access. SSB is a resource unit that includes a synchronization signal, PSS (Primary Synchronization Signal) and / or SSS (Secondary Synchronization Signal), and broadcast information, PBCH (Physical Broadcast Channel). Currently, SSB is transmitted at 20-millisecond intervals (or 40-millisecond, 80-millisecond, or 160-millisecond intervals). Furthermore, when beamforming is primarily implemented, multiple SSBs of 64 or fewer are transmitted in bursts within a half-frame.

[0022] In use cases where bandwidth and / or transmit power are limited (e.g., NTN (Non-Terrestrial Network) or RedCap (Reduced Capability)), repeated SSB transmissions are necessary to ensure synchronization accuracy. However, to accommodate all use cases, the current SSB signal configuration is fixed. This lack of flexibility in transmission schedules makes conventional SSB not necessarily optimal when considering power saving and interference reduction.

[0023] Currently, the 3GPP (3rd Generation Partnership Project) is considering on-demand and optimized (adapted) SSB transmission to reduce power consumption and / or interference. If SSB transmission is made on-demand, base stations will not transmit SSB until a wake-up request (a request for an on-demand signal) is received. In this case, terminal devices cannot detect a base station that is not transmitting SSB through a blind search, and therefore cannot initiate a connection to such a base station. For a terminal device to connect to that base station using an on-demand signal, a trigger from another communication node (e.g., another base station or another terminal device) is required. Therefore, base stations operating in standalone mode have difficulty adapting to on-demand SSB transmission. It is also conceivable that power consumption and / or interference reduction can be achieved by changing the SSB transmission interval to a longer period than the current 20 milliseconds. However, simply increasing the SSB transmission interval leads to a problem of reduced synchronization accuracy in terminal devices.

[0024] Furthermore, regarding the area coverage of wireless communication networks, while population coverage has been improving in recent years, the low area coverage remains a challenge. To address this challenge, it is expected that macrocell coverage will be further expanded in the future. In mountainous areas and / or rural areas, wireless communication networks are expected to operate in environments with a small number of connected terminals (or infrequent connections). Networks operating in environments with a small number of connected terminals (or infrequent connections) require power-efficient communication methods. However, because 5G prioritizes low latency, the initial access signals (synchronization signals and / or broadcast information) transmitted periodically contain a large amount of information. While this large amount of information enables low-latency communication in many use cases, it also increases power consumption. It should be noted that wireless communication use cases are not limited to those requiring power saving. There are, of course, use cases in wireless communication that require low latency. In addition, in 6G networks, the existence of communication nodes (base stations) specialized for specific use cases such as V2X (vehicle-to-vehicle communication) is also envisioned. Therefore, it is anticipated that in the future, there will be a demand to flexibly change the signal configuration of SIB1 according to the use case. Alternatively, it is anticipated that there will be a demand to prepare and operate multiple different SIB1s (including on-demand SIB1s) corresponding to each use case.

[0025] Based on the above, it is anticipated that a challenge for initial access control will be how to modify the transmission schedule from the conventional method in order to conserve power and / or reduce interference. Furthermore, it is anticipated that a challenge for initial access control will be how to optimize the redundant PBCH and the SIB1, which has an excessive amount of information, in order to conserve power and / or reduce interference, and to accommodate diverse use cases.

[0026] <1-2. Details of the Problem> In environments with a large number or diverse range of communication nodes, increasing the number of communication nodes can lead to increased power consumption or increased radio interference problems, potentially preventing the realization of high-performance wireless communication.

[0027] For example, a standalone base station (cell) is detected by a blind search by terminal equipment, requiring it to repeatedly transmit synchronization signals. As the number of communication nodes increases, power consumption increases, or radio interference problems worsen. To save power and / or reduce interference, one might consider lengthening the transmission period of the synchronization signal. However, in this case, the accuracy of time-frequency synchronization at terminal equipment deteriorates. Therefore, there are limits to the power-saving and / or interference-reducing effects of lengthening the transmission period of the synchronization signal.

[0028] Furthermore, in 5G, the SSB signal configuration is fixed to accommodate various use cases. In particular, when beamforming is not performed, the base station transmits the same PBCH for all SSB transmissions that are periodically transmitted. In conventional systems, despite the availability of many radio resources (e.g., resources for multiple SSB transmissions) for synchronization processing, only a small amount of information is transmitted to the terminal device. This problem is particularly significant in use cases where there are limitations on transmission power and / or bandwidth on the network side (e.g., NTN and RedCap).

[0029] To reduce power consumption and / or interference, attempting to make SSB and / or SIB1 transmissions on-demand or optimized requires including more information in the PBCH. For example, the PBCH needs to include optimization information (e.g., transmission period / interval information) and / or signal configuration information (e.g., signal configuration information for waking up on-demand signals). Therefore, achieving power consumption and / or interference reduction is difficult with conventional standards.

[0030] Furthermore, in order to realize wireless communication with high communication performance, it is desirable that information for initial access control (hereinafter also referred to as initial access information) corresponding to various situations is prepared. For example, in order to realize wireless communication with high communication performance, it is desirable that different SIB1 configurations for each use case are prepared as initial access information. However, according to the current standard, only resource information of SIB1 can be notified via PBCH. Therefore, it is difficult to prepare different SIB1 configurations for each use case (or flexibly change the SIB1 configuration for each use case) while maintaining the conventional standard.

[0031] <1-3. Outline of Solution> Accordingly, in the present embodiment, the above problem is solved as follows.

[0032] FIG. 1 is a diagram for explaining the outline of the present embodiment. In the example of FIG. 1, a plurality of communication points (the communication point P shown in FIG. 1 １１ to P １ｎ ) are arranged in the communication environment. n is any integer of 1 or more. A communication point is, for example, a communication node (e.g., a base station, a relay station, or an antenna) that can be accessed by a terminal device (UE shown in FIG. 1). The communication point may be a base station (BS shown in FIG. 1). Communication point P １１ to P １ｎ may each be a communication point controllable by a base station (e.g., an antenna provided in the base station). Furthermore, a cluster composed of a plurality of communication points may be regarded as one communication point. For example, the communication point P shown in FIG. 1 １１ to P １ｎ (the communication point P shown in FIG. 1 １ ) may be regarded as one communication point.

[0033] Figure 1 shows the repeated transmission of an initial access signal from a communication point. The initial access signal is a signal that allows a terminal device to initially access the wireless network. In the example in Figure 1, the initial access signal is a signal / information with the same or similar function, purpose, and configuration as an SSB. For example, the initial access signal is a signal composed of a synchronization signal (e.g., PSS and / or SSS) and broadcast information (e.g., PBCH). Broadcast information may be read as a broadcast signal. Note that the initial access signal may also include broadcast information with the same or similar function, purpose, and configuration as an SIB1.

[0034] In this embodiment, the communication point groups multiple transmissions of the initial access signal in the first period T1 into one group, and intermittently repeats the transmission of this group. That is, the communication point repeatedly transmits this group at intervals of time. In this embodiment, this group is called an SSB group. This group may be specified by the number of repetitions of the initial access signal it contains. In the example in Figure 1, the SSB group (SSB group G shown in Figure 1) consists of four transmissions in the first period T1. In this embodiment, the communication point repeatedly transmits this SSB group G in a second period T2 that is longer than the first period T1, for example. At this time, the communication point intermittently repeats the transmission of SSB group G. That is, the communication point repeatedly transmits SSB group G at intervals of time.

[0035] In this embodiment, the transmission of the initial access signal in the first period T1 is not performed without interruption, but rather multiple transmissions of the initial access signal in the first period T1 (transmissions of SSB group G) are performed intermittently and repeatedly. As a result, the processing required for transmitting the initial access signal is reduced, and the communication point can reduce power consumption. In addition, radio interference is reduced because the transmission of the initial access signal is reduced. Even if the transmission of the initial access signal is reduced, it is transmitted multiple times in a short period (first period T1) within a single SSB group, so the synchronization accuracy of the terminal device does not decrease significantly.

[0036] Furthermore, the communication point may set broadcast information that differs in content from the broadcast information contained in the other initial access signals included in the SSB group G, in at least one of the multiple initial access signals included in the SSB group G (in the example of Figure 1, four SSBs). For example, the communication point may set all of the multiple broadcast information included in the SSB group G (e.g., multiple PBCHs and / or multiple SIB1s) to have different content.

[0037] This increases the amount of information that can be transmitted in the initial access signal, allowing the communication point to prepare initial access information tailored to various situations. For example, the communication point can prepare different SIB1 configurations for each use case (or flexibly change the SIB1 configuration for each use case).

[0038] Having outlined the basics of this embodiment, the communication system 1 of this embodiment will now be described in detail.

[0039] <<2. Configuration of the Communication System>> First, we will explain the configuration of communication system 1.

[0040] Figure 2 shows an example configuration of the communication system 1 according to this embodiment. The communication system 1 comprises a management device 10, a base station 20, and a terminal device 30. The communication system 1 provides a wireless network (mobile network) that enables mobile communication to users through the coordinated operation of each wireless communication device that constitutes the communication system 1.

[0041] The wireless network (mobile network) in this embodiment may be, for example, a cellular network / cell-free network composed of a wireless access network (RAN) and a core network (CN). A cell-free network is a wireless network that eliminates cell boundaries in a conventional cell configuration (cellular network) centered on a base station. The wireless network (mobile network) may also include terminal devices 30. In this embodiment, a wireless communication device is a device that has wireless communication functionality, and in the example of Figure 2, this refers to the base station 20 and the terminal device 30.

[0042] The communication system 1 may include multiple management devices 10, base stations 20, and terminal devices 30. In the example in Figure 2, the communication system 1 includes multiple management devices 10. １ , and 10 ２ It is equipped with a base station 20. １ , 20 ２ , 20 ３ , 20 ４ , and 20 ５ It is equipped with a terminal device 30. １ , 30 ２ , and 30 ３ It is equipped with.

[0043] The terminal device 30 may be configured to connect to the network using radio access technologies (RATs) such as LTE (Long Term Evolution), NR (New Radio), B5G (Beyond 5G), 6G, Wi-Fi®, and Bluetooth®. In this case, the terminal device 30 may be configured to use different radio access technologies (wireless communication methods). For example, the terminal device 30 may be configured to use NR and Wi-Fi. Also, the terminal device 30 may be configured to use different cellular communication technologies / cell-free communication technologies (e.g., LTE, NR, B5G, or 6G). In the following description, the terminal device 30 may be referred to as UE (User Equipment) 40.

[0044] LTE and NR are types of cellular communication technologies that enable mobile communication for terminal devices by arranging multiple cell-like areas covered by devices with electromagnetic wave transmission and reception capabilities (e.g., base stations or TRPs (Transmission and Reception Points)). B5G and 6G are types of cellular / cell-free communication technologies that have the potential to enable mobile communication for terminal devices. Cell-free communication technology is a technology that eliminates cell boundaries in conventional cellular networks. Cell-free communication technology may also be considered a type of cellular communication technology. In this case, it is possible to appropriately replace "cellular" with "cell-free" or vice versa in the following explanation.

[0045] In the following explanation, "LTE" includes LTE-A (LTE-Advanced), LTE-A Pro (LTE-Advanced Pro), and EUTRA (Evolved Universal Terrestrial Radio Access). Furthermore, "NR" includes NRAT (New Radio Access Technology) and FEUTRA (Further EUTRA). A single base station or single TRP may manage one or more cells. In the following explanation, a cell corresponding to LTE will be referred to as an LTE cell, and a cell corresponding to NR will be referred to as an NR cell.

[0046] NR (Radio Wave) is the next generation (fifth generation) wireless access technology following LTE (fourth generation communication including LTE-Advanced and LTE-Advanced Pro). NR is a wireless access technology that can support various use cases, including eMBB (Enhanced Mobile Broadband), mMTC (Massive Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communications). NR was standardized in 3GPP's Rel-15 and later as a technical framework to address the usage scenarios, requirements, and deployment scenarios in these use cases. Furthermore, 3GPP is considering next-generation technologies, including enhancements to the NR standard. For example, in Rel-19, standardization activities are underway for the next-generation communication standard, 6G (B5G (Beyond 5G)).

[0047] 6G is the next generation of cellular / cell-free communication technology following NR (Non-Reactive Network) and 5GS (5G system), which are fifth-generation mobile communication technologies. 6G requires the simultaneous realization of multiple axes: high speed, large capacity, low latency, high reliability, and massive simultaneous connections. 6G includes wireless access technology and network technologies between base stations, core networks, and data networks. Furthermore, 6G includes technologies for the extreme connectivity of eMBB, mMTC, and URLLLC, which were key use cases or requirements in NR. 6G also includes new technologies in new areas. For example, 6G may include technologies related to AI (Cognitive Network, AI Native Air Interface), sensing (including Radar / RF sensing and network as a sensor), and terahertz communication.

[0048] The wireless network described above or below may support at least one of the following wireless access technologies (RATs): LTE, NR, B5G, 6G, etc. LTE, NR, B5G, and 6G are types of cellular / cell-free communication technologies. The wireless access method used by communication system 1 is not limited to LTE, NR, B5G, or 6G, but may also be other wireless access methods such as W-CDMA (Wideband Code Division Multiple Access) or cdma2000 (Code Division Multiple Access 2000).

[0049] Furthermore, the base station 20 may be a ground station or a non-ground station. The non-ground station may be a satellite station or an aircraft station. If the non-ground station is a satellite station, the radio network may be a bent-pipe (transparent) type mobile satellite communication system.

[0050] In this embodiment, "ground station" and "ground base station" refer to base stations and relay stations installed on the ground. Here, "ground" is a broad term that includes not only land but also underground, on water, and underwater. In the following description, "ground station" may be replaced with "gateway."

[0051] Furthermore, LTE base stations are sometimes referred to as eNodeB (Evolved Node B) or eNB. Similarly, NR base stations are sometimes referred to as gNodeB or gNB. Also, 6G base stations are sometimes referred to as 6G NodeB (6GNB). In addition, for LTE, NR, and 6G, terminal equipment (also called mobile stations or terminals) is sometimes referred to as UE (User Equipment). Terminal equipment is a type of communication device and is also called a mobile station or terminal.

[0052] Furthermore, the terminal device 30 may be able to connect to the network using wireless access technologies (wireless communication methods) other than LTE, NR, B5G, 6G, Wi-Fi, and Bluetooth. For example, the terminal device 30 may be able to connect to the network using LPWA (Low Power Wide Area) communication. Also, the terminal device 30 may be able to connect to the network using a proprietary wireless communication standard.

[0053] Here, LPWA communication refers to wireless communication that enables low-power, wide-area communication. For example, LPWA communication refers to IoT (Internet of Things) wireless communication using specified low-power radio (e.g., the 920 MHz band) or the ISM (Industry-Science-Medical) band. LPWA communication may also include LTE-M and / or C-IoT (Cellular IoT), represented by NB-IoT, which operate in the cellular frequency band. The LPWA communication used by the terminal device 30 may conform to the LPWA standard. The LPWA standard may be at least one of, for example, ELTRES®, ZETA, SIGFOX®, LoRaWAN®, LTE-M, and NB-IoT. Of course, the LPWA standard is not limited to these, and other LPWA standards may also be used.

[0054] Each wireless communication device shown in Figure 2 can be considered a device in a logical sense. That is, a part of each wireless communication device may be implemented using a virtual machine (VM), a container such as Docker, etc., and these may be implemented on the same physical hardware.

[0055] In this embodiment, the concept of a wireless communication device includes not only portable mobile devices (terminal devices) such as mobile terminals, but also devices installed on structures or mobile objects. The structure or mobile object itself may be considered a wireless communication device. Furthermore, the concept of a wireless communication device includes not only the terminal device 30, but also the base station 20. A wireless communication device is a type of processing device or information processing device. A wireless communication device can also be described as a transmitting device or a receiving device.

[0056] The configurations of each wireless communication device constituting communication system 1 are described below in detail. Note that the configurations of each wireless communication device shown below are merely examples. The configurations of each wireless communication device may differ from those shown below.

[0057] <2-1. Example of Management Device Configuration> Next, an example of the configuration of the management device 10 will be explained.

[0058] The management device 10 is an information processing device (computer) that manages the wireless network. For example, the management device 10 is an information processing device that manages the communications of the base station 20.

[0059] The management device 10 may be a device that constitutes the core network CN. For example, the management device 10 may be a device that functions as an MME (Mobility Management Entity). Alternatively, the management device 10 may be a device that functions as an AMF (Access and Mobility Management Function) and / or an SMF (Session Management Function). The MME, AMF, and SMF are Control Plane Network Function nodes in the core network CN. The management device 10 may also be a device that functions as a Control Plane Network Function (6G CPNF) in 6G. The 6G CPNF may consist of one or more logical nodes.

[0060] Of course, the functions of the management device 10 are not limited to MME, AMF, SMF, and 6G CPNF. The management device 10 may also be a device that functions as an NSSF (Network Slice Selection Function), AUSF (Authentication Server Function), PCF (Policy Control Function), or UDM (Unified Data Management). Furthermore, the management device 10 may also be a device that functions as an HSS (Home Subscriber Server).

[0061] Furthermore, the management device 10 may also have gateway functionality. For example, the management device 10 may function as an S-GW (Serving Gateway) or a P-GW (Packet Data Network Gateway). The management device 10 may also function as a UPF (User Plane Function). In this case, the management device 10 may have multiple UPFs. The management device 10 may also be a device that functions as a User Plane Network Function (6G UPNF) in 6G.

[0062] The core network (CN) consists of multiple network functions, each of which may be aggregated in a single physical device or distributed across multiple physical devices. In other words, the management device 10 can be distributed across multiple devices. Furthermore, this distributed arrangement may be controlled to be performed dynamically. The base station 20 and the management device 10 constitute a single network and provide wireless communication services to the terminal device 30. The management device 10 may be connected to the internet. The terminal device 30 can utilize various services provided via the base station 20, the management device 10, and the internet.

[0063] Note that the management device 10 does not necessarily have to be a device that constitutes the core network CN. For example, suppose the core network CN is the core network of W-CDMA (Wideband Code Division Multiple Access) or cdma2000 (Code Division Multiple Access 2000). In this case, the management device 10 may be a device that functions as an RNC (Radio Network Controller).

[0064] Figure 3 shows the configuration of the management device 10 according to this embodiment. The management device 10 comprises a communication unit 11, a storage unit 12, and a control unit 13. The configuration shown in Figure 3 is a functional configuration, and the hardware configuration may differ. Furthermore, the functions of the management device 10 may be implemented by statically or dynamically distributing them across multiple physically separated configurations. The management device 10 may be composed of multiple server devices.

[0065] The communication unit 11 is a communication interface for communicating with a wireless communication device (for example, a base station 20). The communication unit 11 may be a network interface or an equipment connection interface. The communication unit 11 may be a LAN (Local Area Network) interface such as a NIC (Network Interface Card), or a USB interface configured by a USB (Universal Serial Bus) host controller or a USB port. The communication unit 11 may be a wired interface or a wireless interface. The communication unit 11 is controlled by the control unit 13.

[0066] The memory unit 12 is a read / write storage device such as DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), flash memory, or a hard disk. The memory unit 12 stores, for example, the connection status of the terminal device 30. The memory unit 12 stores the RRC (Radio Resource Control) status and ECM (EPS Connection Management) or 5G System CM (Connection Management) status of the terminal device 30. The memory unit 12 may also function as a home memory that stores the location information of the terminal device 30.

[0067] The control unit 13 is a controller that controls each part of the management device 10. The control unit 13 may be implemented by a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). More specifically, the control unit 13 may be implemented by the processor executing various programs stored in the internal storage device of the management device 10 using RAM (Random Access Memory) or the like as a working area. The control unit 13 may be implemented by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). Alternatively, the control unit 13 may be implemented by a GPU (Graphics Processing Unit). A CPU, MPU, ASIC, FPGA, and GPU can all be considered as controllers. The control unit 13 may be composed of multiple physically separated objects. For example, the control unit 13 may be composed of multiple semiconductor chips.

[0068] Note that the operation of the control unit 13 may be the same as the operation of the control unit (control unit 23 or control unit 33) of the base station 20 or terminal device 30.

[0069] <2-2. Example of Base Station Configuration> Next, an example of the configuration of base station 20 will be explained.

[0070] Base station 20 is a wireless communication device that communicates wirelessly with other wireless communication devices (for example, terminal device 30 or other base station 20). Base station 20 may communicate wirelessly with terminal device 30 via a relay station, or it may communicate wirelessly with terminal device 30 directly.

[0071] Base station 20 is a device equivalent to a radio base station (for example, BS (Base Station), Node B, eNB, gNB, or 6GNB) or a radio access point (Access Point). Base station 20 may also be a radio relay station. In the following description, base station 20 may be referred to as BS (Base Station), Node B, eNB, gNB, 6GNB, or BS20.

[0072] Base station 20 may be an optical extension device called an RRH (Remote Radio Head). Base station 20 may be a receiving station such as an FPU (Field Pickup Unit). Base station 20 may be an IAB (Integrated Access and Backhaul) donor node or IAB relay node that provides radio access lines and radio backhaul lines by time division multiplexing, frequency division multiplexing, or spatial division multiplexing.

[0073] The wireless access technology used by base station 20 may be cellular communication technology / cell-free communication technology. The wireless access technology used by base station 20 may be wireless LAN technology. The wireless access technology used by base station 20 may be LPWA (Low Power Wide Area) communication technology. However, the wireless access technology used by base station 20 is not limited to these, and other wireless access technologies may be used. The wireless communication used by base station 20 may be wireless communication using millimeter waves or wireless communication using terahertz waves. The wireless communication used by base station 20 may be wireless communication using radio waves or wireless communication using infrared or visible light (optical wireless). In addition, base station 20 may be capable of NOMA (Non-Orthogonal Multiple Access) communication with terminal device 30. Here, NOMA communication refers to communication using non-orthogonal resources (transmission, reception, or both). Base station 20 may also be capable of NOMA communication with other base stations 20.

[0074] Furthermore, base station 20 may be able to communicate with the core network via a base station-core network interface (e.g., NG Interface, S1 Interface, etc.). This interface may be either wired or wireless. Also, base stations may be able to communicate with other base stations via an inter-base station interface (e.g., Xn Interface, X2 Interface, or F1 Interface). This interface may be either wired or wireless.

[0075] The concept of a base station (also called a "base station device") includes not only donor base stations but also relay base stations (also called "relay stations"). A relay station is a wireless communication device that acts as a repeater for a base station. A relay station is a type of base station 20. In the following explanation, the term base station 20 can be replaced with "relay station".

[0076] A relay station may be any one of the following: an RF Repeater, a Smart Repeater, or an Intelligent Surface. A relay station may be a ground station or a non-ground station. A relay station may be a device installed on a mobile device or the mobile device itself. The relay station, together with the base station 20, constitutes a radio access network RAN. The relay station may be a fixed device, a movable device, or a floating device. The cell covered by the relay station may be a macrocell or a small cell.

[0077] Furthermore, as long as the relay function is fulfilled, the device on which the relay station is installed is not limited to a specific device. The relay station may be installed in terminal devices such as smartphones, in automobiles, trains, or rickshaws, in balloons, airplanes, or drones, or in home appliances such as televisions, game consoles, air conditioners, refrigerators, or lighting fixtures. In addition, any device with a relay function may be considered the relay station itself.

[0078] The relay station may also be an IAB relay node. The relay station may operate as an IAB-MT (IAB - Mobile Termination) with respect to the IAB donor node that provides backhaul, and as an IAB-DU (IAB - Distributed Unit) with respect to the terminal device 30 that provides access. The IAB donor node may be, for example, a base station 20. In this case, the IAB donor node may operate as an IAB-CU (IAB - Central Unit).

[0079] The concept of a base station may include roadside units (RSUs). Furthermore, the concept of a base station may include not only structures equipped with base station functions, but also equipment installed on those structures.

[0080] Structures include buildings such as skyscrapers, houses, transmission towers, train stations, airports, ports, office buildings, school buildings, hospitals, factories, commercial facilities, and stadiums. The concept of structures also includes not only buildings but also non-building structures such as tunnels, bridges, dams, walls, and steel columns, as well as equipment such as cranes, gates, and wind turbines. The concept of structures also includes not only structures on land (on the surface in the narrow sense) or underground, but also structures on water such as piers or megafloats, and underwater structures such as oceanographic observation equipment. A base station can also be described as an information processing device.

[0081] Base station 20 may be a donor station or a relay station. Furthermore, base station 20 may be a fixed station or a mobile station. A mobile station is a wireless communication device (e.g., a base station) configured to be mobile. In this case, base station 20 may be a device installed on a mobile device or the mobile device itself. For example, a relay station with mobility can be considered a base station 20 as a mobile station. Additionally, devices that are inherently mobile and equipped with base station functions (or at least some of the functions of a base station), such as vehicles, UAVs (Unmanned Aerial Vehicles) represented by drones, and smartphones, also qualify as base station 20 as a mobile station.

[0082] Here, the moving object may be a mobile device such as a smartphone or mobile phone. The moving object may also be a moving object that moves on land (ground in the narrow sense) (for example, a car, bicycle, bus, truck, motorcycle, train, or linear motor car), or a moving object that moves underground (for example, inside a tunnel) (for example, a subway). The moving object may also be a moving object that moves on water (for example, a passenger ship, cargo ship, or hovercraft), or a moving object that moves underwater (for example, a submersible boat, submarine, or unmanned submersible). The moving object may also be a moving object that moves within the atmosphere (for example, an airplane, airship, or drone).

[0083] Base station 20 may be a ground base station (ground station) installed on the ground. Base station 20 may be a base station located on a structure on the ground, or a base station installed on a mobile body moving on the ground. Base station 20 may be an antenna installed on a structure such as a building and a signal processing device connected to that antenna. Base station 20 may be the structure or the mobile body itself. "Ground" refers to ground in a broad sense, including not only land (ground in the narrow sense) but also underground, on water, and underwater. Base station 20 is not limited to a ground base station. If communication system 1 is a satellite communication system, base station 20 may be an aircraft station. From the perspective of a satellite station, an aircraft station located on Earth is a ground station.

[0084] The base station 20 is not limited to a ground station. The base station 20 may be a non-ground base station (non-ground station) capable of floating in the air or space. The base station 20 may be an aircraft station or a satellite station.

[0085] A satellite station is a radio communication device capable of floating outside the atmosphere. A satellite station may be a device mounted on a spacecraft such as an artificial satellite, or it may be the spacecraft itself. A spacecraft is a mobile object that moves outside the atmosphere. A spacecraft may be at least one of the following: an artificial satellite, a spacecraft, a space station, and a probe. Of course, a spacecraft may also be an artificial celestial body other than these. The satellite that becomes a satellite station may be a low Earth orbit (LEO) satellite, a medium Earth orbit (MEO) satellite, a geostationary Earth orbit (GEO) satellite, or a highly elliptical orbit (HEO) satellite. A satellite station may be a device mounted on a low Earth orbit satellite, a medium Earth orbit satellite, a geostationary satellite, or a highly elliptical orbit satellite.

[0086] An aircraft station is a radio communication device capable of floating within the atmosphere of an aircraft or similar vessel. An aircraft station may be a device mounted on an aircraft or similar vessel, or it may be the aircraft itself. The concept of an aircraft includes not only heavy aircraft such as airplanes or gliders, but also light aircraft such as balloons or airships. The concept of an aircraft also includes not only heavy or light aircraft, but also rotary-wing aircraft such as helicopters or autogyros. An aircraft station, or an aircraft on which an aircraft station is mounted, may be an unmanned aerial vehicle such as a drone.

[0087] The concept of unmanned aerial vehicles includes unmanned aircraft systems (UAS) and tethered UAS. It also includes lighter than air UAS (LTA) and heavier than air UAS (HTA). Furthermore, it includes high-altitude UAS platforms (HAPs).

[0088] The coverage size of the base station 20 may be relatively large, such as a macrocell, or relatively small, such as a picocell. The coverage size of the base station 20 may also be extremely small, such as a femtocell. The base station 20 may have a beamforming function. The base station 20 may form cells or service areas for each beam. Furthermore, or alternatively, in addition to beamforming which gives directionality to the beam, the base station 20 may have a function that delivers the desired wave precisely to a predetermined point by further considering distance information from the base station 20's antenna. This function may be called beam focusing or point forming. The base station 20 may also be configured to acquire sensing data by performing sensing using the beam.

[0089] Figure 4 shows the configuration of a base station 20 according to this embodiment. The base station 20 comprises a wireless communication unit 21, a storage unit 22, and a control unit 23. However, the configuration shown in Figure 4 is a functional configuration, and the hardware configuration may differ. Furthermore, the functions of the base station 20 may be distributed and implemented across multiple physically separated configurations.

[0090] Note that the base station 20 does not necessarily have to have all of the above-mentioned or later-described configurations. Also, the base station 20 may have configurations other than those described above or later.

[0091] The wireless communication unit 21 is a signal processing unit for wireless communication with other wireless communication devices (for example, at least one of terminal devices 30 and other base stations 20). The wireless communication unit 21 may be called a wireless transceiver or simply a transceiver. In this case, the wireless communication unit 21 may be a transceiver conforming to the specifications defined in the 3GPP Technical Specification (TS) (hereinafter referred to as a 3GPP transceiver). The 3GPP transceiver may be a 3G transceiver, a 4G (LTE) transceiver, a 5G (NR) transceiver, or a 5G or later generation transceiver (for example, 6G). The wireless communication unit 21 is controlled by the control unit 23. The wireless communication unit 21 supports one or more wireless access schemes. The wireless communication unit 21 may support at least one of 4G (LTE), 5G (NR), B5G (Beyond 5G), and 6G. The wireless communication unit 21 may support 4G (LTE), 5G (NR), B5G, and 6G, as well as W-CDMA and cdma2000, etc. The wireless communication unit 21 may also support automatic retransmission technologies such as HARQ (Hybrid Automatic Repeat reQuest). Some or all of the processing performed by the wireless communication unit 21 may be performed by the control unit 23.

[0092] The wireless communication unit 21 comprises a transmission processing unit 211, a reception processing unit 212, and an antenna 213. At least one of the transmission processing unit 211, the reception processing unit 212, and the antenna 213 may be considered as the wireless communication unit 21. The wireless communication unit 21 may include multiple transmission processing units 211, reception processing units 212, and antennas 213. If the wireless communication unit 21 supports multiple wireless access methods, each part of the wireless communication unit 21 may be configured separately for each wireless access method. The transmission processing unit 211 and the reception processing unit 212 may be configured separately for 4G (LTE), 5G (NR), B5G, and 6G. The antenna 213 may be composed of multiple antenna elements, for example, multiple 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 that uses vertical polarization (V polarization) and horizontal polarization (H polarization) (or a polarization beamforming function that uses dual polarization in polarization directions of 45 degrees and -45 degrees from the vertical). The wireless communication unit 21 may also transmit sensing signals as described later.

[0093] The transmission processing unit 211 performs the transmission processing of downlink control information and downlink data. For example, the transmission processing unit 211 encodes the downlink control information and downlink data input from the control unit 23 using encoding methods such as block encoding, convolutional encoding, or turbo encoding. Here, encoding may be performed using polar code or LDPC code (Low Density Parity Check Code). The transmission processing unit 211 then modulates the encoded bits using a predetermined modulation method (for example, BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), 16QAM (16 Quadrature Amplitude Modulation), 64QAM (64 Quadrature Amplitude Modulation), 256QAM (256 Quadrature Amplitude Modulation), or a higher-order multi-level modulation method). In this case, the signal points on the constellation do not necessarily need to be equidistant. Furthermore, the constellation may be a non-uniform constellation (NUC). The transmission processing unit 211 then multiplexes the modulation symbols and downlink reference signals for each channel and places them on predetermined resource elements. The transmission processing unit 211 then performs various signal processing on the multiplexed signals. For example, the transmission processing unit 211 performs processing such as conversion to the frequency domain using the Fast Fourier Transform, addition of guard intervals (cyclic prefixes), generation of baseband digital signals, conversion to analog signals, quadrature modulation, upconversion, removal of extraneous frequency components, and power amplification. The signals generated by the transmission processing unit 211 are transmitted from the antenna 213.

[0094] The receiving processing unit 212 processes the uplink signal received via the antenna 213. For example, the receiving processing unit 212 performs down-conversion, removal of unwanted frequency components, amplification level control, quadrature demodulation, conversion to a digital signal, removal of guard intervals (cyclic prefixes), and extraction of frequency domain signals using Fast Fourier Transform on the uplink signal. Then, the receiving processing unit 212 separates the uplink channels and uplink reference signals, such as PUSCH (Physical Uplink Shared Channel) and PUCCH (Physical Uplink Control Channel), from the processed signal. The receiving processing unit 212 also demodulates the received signal using a modulation scheme such as BPSK or QPSK for the modulation symbols of the uplink channels. The modulation scheme used for demodulation may be 16QAM, 64QAM, or 256QAM. In this case, the signal points on the constellation do not necessarily need to be equidistant. The constellation may be a non-uniform constellation (NUC). The receiving processing unit 212 then performs decoding on the encoded bits of the demodulated uplink channel. The decoded uplink data and uplink control information are output to the control unit 23.

[0095] Antenna 213 is an antenna device that converts electric current and radio waves to each other. Antenna 213 may consist of one antenna element, for example, one patch antenna. Antenna 213 may consist of multiple antenna elements, for example, multiple patch antennas. If antenna 213 consists of multiple 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 the radio signal using multiple antenna elements. Antenna 213 may be a dual-polarization antenna. If antenna 213 is a dual-polarization antenna, the wireless communication unit 21 may use vertical polarization (V polarization) and horizontal polarization (H polarization) (or dual polarization in polarization directions of 45 degrees and -45 degrees from the vertical) when transmitting a radio signal. The wireless communication unit 21 may control the directivity of the transmitted radio signal using vertical polarization and horizontal polarization (or dual polarization in polarization directions of 45 degrees and -45 degrees from the vertical). Furthermore, the wireless communication unit 21 may transmit and receive signals spatially multiplexed through multiple layers composed of multiple antenna elements.

[0096] The memory unit 22 is a read / write storage device such as DRAM, SRAM, flash memory, or a hard disk.

[0097] The control unit 23 is a controller that controls various parts of the base station 20. The control unit 23 controls the wireless communication unit 21 to perform wireless communication with other wireless communication devices (for example, a terminal device 30 or another base station 20). The control unit 23 may be implemented by a processor such as a CPU or MPU. Specifically, the control unit 23 may be implemented by the processor executing various programs stored in the internal memory of the base station 20 using RAM or the like as a working area. The control unit 23 may be implemented by an integrated circuit such as an ASIC or FPGA. Furthermore, the control unit 23 may be implemented by a GPU. CPU, MPU, ASIC, FPGA, and GPU can all be considered as controllers. The control unit 23 may be composed of multiple physically separated objects. For example, the control unit 23 may be composed of multiple semiconductor chips.

[0098] The control unit 23 comprises at least one block of the following: a transmission control unit 231, a reception control unit 232, an acquisition unit 233, or a state control unit 234. The control unit 23 may comprise multiple of these blocks, or it may comprise only one of each.

[0099] Each block constituting the control unit 23 (transmission control unit 231 to state control unit 234) is a functional block that indicates the function of the control unit 23. These functional blocks may be software blocks or hardware blocks. For example, each of the above-mentioned functional blocks may be a single software module implemented in software (including microprograms), or a single circuit block on a semiconductor chip (die). Of course, each functional block may also be a single processor or a single integrated circuit. The control unit 23 may be composed of functional units different from the above-mentioned functional blocks. The configuration of the functional blocks is arbitrary. The operation of the control unit 23 may be the same as the operation of the control unit (control unit 13 or control unit 33) of the management device 10 or terminal device 30.

[0100] In some embodiments, the base station 20 may be composed of a collection of multiple physical or logical devices. For example, the base station 20 in this embodiment may be distinguished into multiple devices such as a BBU (Baseband Unit) and an RU (Radio Unit). The base station 20 may be interpreted as a collection of these multiple devices. Furthermore, the base station may consist of either a BBU or an RU, or both. The BBU and RU may be connected by a predetermined interface, such as an eCPRI (enhanced Common Public Radio Interface).

[0101] RU may be rephrased as RRU (Remote Radio Unit) or RD (Radio DoT). RU may correspond to gNB-DU (gNB Distributed Unit), which will be described later. BBU may correspond to gNB-CU (gNB Central Unit), which will be described later. RU may be a device integrally formed with the antenna. The antenna of the base station 20, for example, an antenna integrally formed with the RU, may employ an Advanced Antenna System and support MIMO (Multiple-Input Multiple-Output) or beamforming, such as FD-MIMO. The antenna of the base station 20 may have, for example, 64 transmitting antenna ports and 64 receiving antenna ports.

[0102] The antenna mounted on the RU may be an antenna panel composed of one or more antenna elements, and the RU may be equipped with one or more antenna panels. The RU may be equipped with two types of antenna panels: a horizontally polarized antenna panel and a vertically polarized antenna panel. The RU may be equipped with two types of antenna panels: a right-hand circularly polarized antenna panel and a left-hand circularly polarized antenna panel, or an antenna panel with a polarization direction of 45 degrees from the vertical and an antenna panel with a polarization direction of -45 degrees. Multiple antennas with these multiple polarization directions may be mounted on a single antenna panel. The RU may form and control independent beams for each antenna panel.

[0103] Multiple base stations 20 may be connected to each other. One or more base stations 20 may be included in a radio access network (RAN). In this case, the base stations 20 may simply be referred to as RAN, RAN node, AN (Access Network), or AN node, etc. In LTE, RAN may be called EUTRAN (Enhanced Universal Terrestrial RAN). In NR, RAN may be called NGRAN. Also, in 6G, RAN may be called 6GRAN. In W-CDMA (UMTS), RAN may be called UTRAN.

[0104] An LTE base station 20 may be referred to as eNodeB (Evolved Node B) or eNB. In this case, EUTRAN includes one or more eNodeBs (eNBs). An NR base station 20 may be referred to as gNodeB or gNB. In this case, NGRAN includes one or more gNBs. A 6G base station may be referred to as 6GNodeB, 6gNodeB, 6GNB, or 6gNB. In this case, 6GRAN includes one or more 6GNBs. EUTRAN may also include gNBs (en-gNBs) connected to the core network (EPC) in an LTE communication system (EPS). NGRAN may also include ng-eNBs connected to the core network 5GC in a 5G communication system (5GS).

[0105] If base station 20 is an eNB, gNB, 6GNB, etc., base station 20 may be referred to as 3GPP Access. If base station 20 is an Access Point, base station 20 may be referred to as Non-3GPP Access. Base station 20 may also be an optical extension device called RRH (Remote Radio Head). If base station 20 is a gNB, base station 20 may be a combination of gNB-CU and gNB-DU described later, or it may be either gNB-CU or gNB-DU.

[0106] Here, the gNB-CU hosts multiple upper layers of the Access Stratum (e.g., RRC (Radio Resource Control), SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol)) for communication with the UE. On the other hand, the gNB-DU hosts multiple lower layers of the Access Stratum (e.g., RLC (Radio Link Control), MAC (Medium Access Control), PHY (Physical layer)). That is, among the messages / information described later, RRC signaling (quasi-static notifications) may be generated by the gNB-CU, while MAC CE and DCI (dynamic notifications) may be generated by the gNB-DU. Alternatively, among the RRC configuration (quasi-static notifications), some 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 via the F1 interface.

[0107] Base station 20 may be configured to communicate with other base stations. If multiple base stations 20 are eNBs or a combination of eNB and en-gNB, these base stations 20 may be connected by an X2 interface. If multiple base stations 20 are gNBs or a combination of gn-eNB and gNB, these base stations 20 may be connected by an Xn interface. If multiple base stations 20 are a combination of gNB-CU and gNB-DU, these base stations 20 may be connected by an F1 interface. Messages / information described later (e.g., RRC signaling, MAC CE (MAC Control Element), or DCI (Downlink Control Information), etc.) may be transmitted between multiple base stations 20 via these inter-base station interfaces (e.g., X2 interface, Xn interface, or F1 interface, etc.).

[0108] The cells provided by the base station 20 are sometimes called Serving Cells. The concept of a Serving Cell includes PCell (Primary Cell) and SCell (Secondary Cell). When dual connectivity is provided to the terminal device 30, the PCell provided by the Master Node (MN) and zero or one or more SCells are sometimes called a Master Cell Group. Dual connectivity may be at least one of EUTRA-EUTRA Dual Connectivity, EUTRA-NR Dual Connectivity (ENDC), EUTRA-NR Dual Connectivity with 5GC, NR-EUTRA Dual Connectivity (NEDC), NR-NR Dual Connectivity, NR-6G Dual Connectivity, and 6G-NR Dual Connectivity. Of course, dual connectivity is not limited to these.

[0109] A serving cell may include a PSCell (Primary Secondary Cell, or Primary SCG Cell). When dual connectivity is provided to the terminal device 30, the PSCell provided by the SN (Secondary Node) and zero or one or more SCells may be called an SCG (Secondary Cell Group). Unless special settings are made (e.g., PUCCH on SCell), the physical uplink control channel (PUCCH) is transmitted by PCell and PSCell, but not by SCell. Radio link failure is detected by PCell and PSCell, but not by SCell (and does not need to be detected). Because PCell and PSCell play special roles within the serving cell, they are also called SpCell (Special Cell).

[0110] A single cell may be associated with one downlink component carrier and one uplink component carrier. The system bandwidth corresponding to a single cell may be divided into multiple Bandwidth Parts (BWPs). In this case, one or more BWPs may be configured in the terminal device 30, and one BWP may be used by the terminal device 30 as an active BWP. The radio resources available to the terminal device 30, such as frequency band, numerology (subcarrier spacing), or slot configuration, may differ for each cell, each component carrier, or each BWP.

[0111] <2-3. Example of Terminal Device Configuration> Next, an example of the configuration of the terminal device 30 will be explained.

[0112] Terminal device 30 is a wireless communication device that performs wireless communication with other wireless communication devices (for example, base station 20 or other terminal device 30). In the following description, terminal device 30 may be referred to as UE (User Equipment) or UE30.

[0113] The terminal device 30 can be any form of information processing device (computer). For example, the terminal device 30 may be a mobile terminal such as a mobile phone, smart device (smartphone or tablet), PDA (Personal Digital Assistant), or notebook PC. Alternatively, the terminal device 30 may be a communication module connected to an information processing device (for example, an imaging device without wireless communication capabilities) and providing wireless communication capabilities to the information processing device. Alternatively, the terminal device 30 may be an imaging device equipped with wireless communication capabilities (for example, a camcorder).

[0114] Furthermore, the terminal device 30 may be a motorcycle or mobile relay vehicle equipped with a communication device such as an FPU (Field Pickup Unit). The terminal device 30 may also be an M2M (Machine to Machine) device or an IoT (Internet of Things) device. Additionally, the terminal device 30 may be a wearable device such as a smartwatch.

[0115] Furthermore, the terminal device 30 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. In this case, the XR device may be a glasses-type device such as AR glasses or MR glasses, or a head-mounted device such as a VR head-mounted display. When the terminal device 30 is an XR device, the terminal device 30 may be a standalone device consisting only of a user-worn portion (e.g., a glasses portion). Alternatively, the terminal device 30 may be a terminal-linked device consisting of a user-worn portion (e.g., a glasses portion) and a terminal portion (e.g., a smart device) that is linked to that portion.

[0116] Terminal device 30 may be capable of NOMA communication with other wireless communication devices (for example, base station 20 or other terminal device 30). Terminal device 30 may use automatic retransmission technology such as HARQ when communicating with other wireless communication devices. Terminal device 30 may be capable of sidelink communication with other terminal devices 30. Terminal device 30 may use automatic retransmission technology such as HARQ when performing sidelink communication. Terminal device 30 may be capable of NOMA communication when performing sidelink communication with other terminal devices 30. Terminal device 30 may be capable of LPWA communication with other wireless communication devices. The wireless communication used by terminal device 30 may be wireless communication using millimeter waves. The wireless communication used by terminal device 30, including sidelink communication, may be wireless communication using radio waves, or wireless communication using infrared or visible light, i.e., optical wireless communication.

[0117] As described above, terminal device 30 may be capable of side-link communication with other terminal devices 30. One use case for side-link communication is V2X (Vehicle-to-everything) communication. Examples of V2X communication include V2V (Vehicle-to-vehicle), V2I (Vehicle-to-infrastructure), V2P (Vehicle-to-pedestrian), or V2N (Vehicle-to-network). Specific use cases for V2X communication include platooning, advanced driving, extended sensors, or remote driving.

[0118] The terminal device 30 may be a mobile wireless communication device, i.e., a mobile device. The terminal device 30 may be a wireless communication device installed on a mobile device, or it may be the mobile device itself. The terminal device 30 may be a vehicle that moves on roads, such as an automobile, bus, truck, or motorcycle, or a train that runs on tracks, or it may be a wireless communication device mounted on such a vehicle. The mobile device may be a mobile terminal, or it may be a mobile device that moves on land (ground in the narrow sense), underground, on water, or underwater. Furthermore, the mobile device may be a mobile device that moves within the atmosphere, such as an aircraft, airship, balloon, or helicopter, or it may be a mobile device that moves outside the atmosphere, such as an artificial satellite. The mobile device may also be a UAV (Unmanned Aerial Vehicle) such as a drone. Furthermore, the terminal device 30 may be a wireless communication device mounted on a mobile device.

[0119] The terminal device 30 may be capable of communicating with multiple base stations 20 or multiple cells simultaneously. If one base station 20 supports a communication area via multiple cells (for example, pCell or sCell), communication between the base station 20 and the terminal device 30 can be achieved by bundling these multiple cells using technologies such as carrier aggregation (CA), dual connectivity (DC), or multi-connectivity (MC). Alternatively, communication between the terminal device 30 and multiple base stations 20 can be achieved via cells of different base stations 20 using coordinated multi-point transmission and reception (CoMP) technology.

[0120] The terminal device 30 may be able to communicate with a plurality of base stations 20 or a plurality of cells. The terminal device 30 may also transmit and / or receive sensing signals to and from each of the plurality of base stations 20. The terminal device 30 may be configured to receive information about sensing signals (e.g., information about resources) from at least one of the plurality of base stations 20, or to receive information about sensing signals (e.g., information about resources) from each of the plurality of base stations 20. The terminal device 30 may also transmit and / or receive sensing signals in each of the plurality of cells. The terminal device 30 may be configured to receive information about sensing signals (e.g., information about resources) from at least one of the plurality of cells, or to receive information about sensing signals (e.g., information about resources) in each of the plurality of cells.

[0121] The terminal device 30 may be a relay terminal that relays communication to a remote terminal.

[0122] Multistatic sensing may be performed at the base station 20, the remote terminal, and the relay terminal. Specifically, sensing signals may be transmitted from both the base station 20 and the relay terminal. The remote terminal may receive sensing signals transmitted from both the base station 20 and the relay terminal.

[0123] The base station 20 and / or relay terminal may transmit to the relay terminal and / or remote terminal information regarding sensing signals transmitted and / or received by the relay terminal and / or remote terminal. In other words, the relay terminal and / or remote terminal may receive from the base station 20 and / or relay terminal information regarding sensing signals transmitted and / or received by the relay terminal and / or remote terminal.

[0124] Figure 5 shows the configuration of the terminal device 30 according to this embodiment. The terminal device 30 comprises a wireless communication unit 31, a storage unit 32, and a control unit 33. The configuration shown in Figure 5 is a functional configuration, and the hardware configuration may differ. Furthermore, the functions of the terminal device 30 may be distributed and implemented across multiple physically separated configurations.

[0125] Note that the terminal device 30 does not necessarily have all of the above-mentioned or later-described configurations. Furthermore, the terminal device 30 may have configurations other than those described above or later. The terminal device 30 may have a beamforming function. Furthermore, the terminal device 30 may be configured to acquire sensing data by performing sensing using a beam.

[0126] The wireless communication unit 31 is a signal processing unit for wireless communication with other wireless communication devices (for example, a base station 20 or other terminal device 30). The wireless communication unit 31 may be called a wireless transceiver or simply a transceiver. In this case, the wireless communication unit 31 may be a transceiver conforming to the standards specified in the 3GPP technical specifications (hereinafter referred to as a 3GPP transceiver). The 3GPP transceiver may be a 3G transceiver, a 4G (LTE) transceiver, a 5G (NR) transceiver, or a transceiver of a 5G or later generation. The wireless communication unit 31 is controlled, for example, by a control unit 33. The wireless communication unit 31 supports one or more wireless access schemes. The wireless communication unit 31 may support at least one of 4G (LTE), 5G (NR), B5G, and 6G. The wireless communication unit 31 may support 4G (LTE), 5G (NR), B5G, and 6G, as well as W-CDMA and cdma2000, etc. The wireless communication unit 31 may also support automatic retransmission technologies such as HARQ. Some or all of the processing performed by the wireless communication unit 31 may be performed by the control unit 33.

[0127] The wireless communication unit 31 comprises a transmission processing unit 311, a reception processing unit 312, and an antenna 313. At least one of the transmission processing unit 311, the reception processing unit 312, and the antenna 313 may be considered as the wireless communication unit 31. The wireless communication unit 31 may include multiple transmission processing units 311, reception processing units 312, and antennas 313. If the wireless communication unit 31 supports multiple wireless access methods, each part of the wireless communication unit 31 may be configured separately for each wireless access method. The transmission processing unit 311 and the reception processing unit 312 may be configured separately for 4G (LTE), 5G (NR), B5G, and 6G. The antenna 313 may be composed of multiple antenna elements, for example, multiple 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 that uses vertical polarization (V polarization) and horizontal polarization (H polarization) (or a polarization beamforming function that uses dual polarization in polarization directions of 45 degrees and -45 degrees from the vertical). The wireless communication unit 31 may also transmit the sensing signals described above or below.

[0128] The memory unit 32 is a read / write storage device such as DRAM, SRAM, flash memory, or a hard disk.

[0129] The control unit 33 is a controller that controls each part of the terminal device 30. The control unit 33 controls the wireless communication unit 31 to perform wireless communication with other wireless communication devices (for example, a base station 20 or another terminal device 30). The control unit 33 may be implemented by a processor such as a CPU or MPU. More specifically, the control unit 23 may be implemented by the processor executing various programs stored in the internal storage device of the terminal device 30 using RAM or the like as a working area. The control unit 33 may be implemented by an integrated circuit such as an ASIC or FPGA. CPU, MPU, ASIC, and FPGA can all be considered as controllers. The control unit 33 may be implemented by a GPU. CPU, MPU, ASIC, FPGA, and GPU can all be considered as controllers. The control unit 33 may be composed of multiple physically separated objects. For example, the control unit 33 may be composed of multiple semiconductor chips.

[0130] The control unit 33 comprises at least one block consisting of a transmission control unit 331, a reception control unit 332, and an acquisition unit 333. The control unit 33 may comprise multiple of these blocks, or it may comprise only one of each.

[0131] Each block constituting the control unit 33 (transmission control unit 331 to acquisition unit 333) is a functional block that represents the function of the control unit 33. These functional blocks may be software blocks or hardware blocks. For example, each of the above-mentioned functional blocks may be a single software module implemented in software (including microprograms), or a single circuit block on a semiconductor chip (die). Of course, each functional block may also be a single processor or a single integrated circuit. The control unit 33 may be composed of functional units different from the above-mentioned functional blocks. The configuration of the functional blocks is arbitrary. The operation of the control unit 33 may be the same as the operation of the control unit (control unit 13 or control unit 23) of the management device 10 or base station 20.

[0132] <<3. Prerequisite Technology>> The configuration of the communication system 1 has been described above. Before describing the operation of the communication system 1 of this embodiment in detail, we will now explain the technology that is a prerequisite for describing the operation of the communication system 1 of this embodiment.

[0133] <3-1. Communication Points> First, let's explain communication points.

[0134] In conventional communication systems, communication control (e.g., initial access control and / or mobility control) was performed on a cell-by-cell basis. In other words, a conventional cell can be defined as a unit of transmission and reception points (communication nodes) for communication control.

[0135] However, in the future, in addition to the increasing complexity of communication topologies, it is anticipated that high-frequency bands such as millimeter waves or terahertz waves will be utilized. Therefore, future communication systems will require higher density units for communication control. In this embodiment, this unit of communication control is called a communication point, rather than a cell.

[0136] In this embodiment, a cell-free communication system is assumed as an example of a communication system that uses communication points. However, the point of this embodiment is not a change in the definition of a cell. The method of this embodiment can be applied to communication systems in which the definition of a cell remains the same as before. In other words, a cell-free communication system is one type of communication system to which the method of this embodiment can be applied, but the method of this embodiment can also be applied to communication systems other than cell-free communication systems. For example, the method of this embodiment can also be applied to a distributed MIMO system, a distributed antenna system, a multi-TRP system, or a multi-AP (Access Point) system.

[0137] <3-1-1. Definition of a Communication Point> A communication point is, for example, a wireless resource when a communication service is provided. A communication point may also be referred to as a communication node or node.

[0138] The communication point may be a conventional cell (a conventional planar cell formed by the base station 20; hereinafter referred to as a classic cell). However, the communication point is not limited to a cell; for example, it may be a beam in beamforming (hereinafter also referred to as a beam cell) or a point in point forming (hereinafter also referred to as a point cell). Here, point forming is a technique that concentrates power at a specific point by utilizing the phase difference of the near field.

[0139] In addition, communication points may be radio resources divided spatially, temporally, or frequency-wise. Multiple radio resources may be multiplexed spatially, temporally, or frequency-wise to form a communication point. A wireless communication device (e.g., base station 20 and / or terminal device 30) can identify each communication point by some means.

[0140] The communication point in this embodiment may be any of the following (A1) to (A15). The description of "communication point" in this embodiment can be replaced with a description indicating any of the following (A1) to (A15).

[0141] (A1) Cell (classic cell) (A2) Base station (e.g., gNB) (A3) Relay station (A4) TRP (Transmission and 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)

[0142] When the communication point is a cell (classic cell / beam cell / point cell), it may also be called a macrocell, PCell (Primary Cell), Cell A, or Standalone cell. Furthermore, when the communication point is a base station, it may also be called a gNB or eNB.

[0143] Furthermore, the communication point in this embodiment may be a cluster composed of multiple elements selected from (A1) to (A15) described above. The term "communication point" in this embodiment can be replaced with a term indicating this cluster.

[0144] Furthermore, the communication point in this embodiment may also be defined as (B1) to (B2) below, in addition to or instead of the above.

[0145] (B1) A node that transmits a synchronization signal and / or broadcast control information. For example, a communication point may be a unit (node) that the terminal device 30 can recognize as the source of the first signal and / or the first broadcast information (e.g., SSB / SIB1) described later. Alternatively, for example, a communication point may be a unit (node) that the terminal device 30 can recognize as the source of the second signal and / or the second broadcast information (e.g., SSB / SIBx) described later. x in SIBx is any integer of 1 or more. The terminal device 30 may recognize the communication point that transmits the first signal and / or the first broadcast information and the communication point that transmits the second signal and / or the second broadcast information as different communication points.

[0146] (B2) A unit defined based on QCL (Quasi-co-location). For example, a set of antenna ports having the same QCL may be recognized as a single communication point (cluster). A communication point may be defined or recognized by a TCI state. For example, a TRP, antenna, or antenna element defined or recognized by a single TCI state may be defined as a single communication point. Here, the TCI state is information about the QCL (Quasi-Co-Location) of a signal and / or channel.

[0147] Furthermore, the communication point in this embodiment does not need to be fixed and may be a mobile node. Moreover, the communication point in this embodiment does not need to be a terrestrial node and may be a non-terrestrial node. For example, the communication point in this embodiment may be a satellite, a drone, or an Unmanned Aerial Vehicle (UAV).

[0148] As described above, the base station 20 can be defined as a communication point. However, in this embodiment, the base station 20 does not necessarily have to be a communication point. For example, the base station 20 (or the functions of the base station 20 in this embodiment) may be a communication node capable of controlling the communication points connected to the base station 20. For example, the base station 20 in this embodiment may be a node on the core network CN side of the communication points.

[0149] Furthermore, the base station 20 can be implemented in various forms from a device perspective. For example, the base station 20 may be included in multiple communication points. The base station 20 may also control other communication points. Alternatively, for example, the base station 20 may be independent as a communication node between the core network CN and the communication points. Alternatively, for example, the base station 20 may be included in the core network CN.

[0150] Furthermore, the communication points in this embodiment may be clusters formed by clustering. The definitions of clustering and clusters are as follows, for example.

[0151] (Clustering) Clustering refers to configuring, for example, one or more communication nodes (or one or more candidate communication nodes) that are connected simultaneously. Information about the QCL can be configured for each of the clustered communication nodes. For example, suppose a communication node is an antenna port, and multiple communication nodes (i.e., antenna ports) are configured in one cluster. In this case, in that cluster, communication nodes with the same TRP will be indicated as having the same QCL, and communication nodes with different TRPs will be indicated as having different QCLs. In other words, a single cluster can have a mix of communication nodes with the same QCL and communication nodes with different QCLs.

[0152] (Cluster) A cluster refers to, for example, a set (list) of clustered communication nodes. For example, a cluster may be a set of communication nodes configured in RRC signaling. For example, a cluster may be a set of communication nodes configured in RRC signaling and also be a candidate for the communication nodes that actually communicate. Note that the communication nodes that actually communicate may be defined as subclusters.

[0153] Furthermore, the multiple entities constituting a cluster may be the communication points described above. In other words, a cluster may be composed of multiple communication points. In this case, the term "communication node" as described above or below can be replaced with "communication point".

[0154] A cluster may be referred to by a different name. Alternatively, a cluster may be defined by a different definition. For example, a cluster may be referred to / defined as shown in at least one of (C1) to (C6) below.

[0155] (C1) A node set cluster may be referred to as a node set.

[0156] (C2) Zone (Area) A zone is a spatial area that can be defined according to physical or virtual location. A given zone may contain multiple communication nodes. A zone may also be simply referred to as an area.

[0157] (C3) Cell set (cell) In particular, when the communication node is a cell (classic cell), the cluster of this embodiment may be called a cell set. A cell set may also be simply called a cell.

[0158] (C4) Antenna port set In particular, when the communication node is an antenna port, the cluster of this embodiment may be referred to as an antenna port set.

[0159] (C5) Beamset In particular, when the communication node is a beam (beam cell), the cluster of this embodiment may be referred to as a beamset.

[0160] (C6) Point set In particular, when the communication nodes are points (point cells), the cluster of this embodiment may be referred to as a point set.

[0161] Furthermore, each cluster may be assigned a unique identifier (cluster ID).

[0162] Furthermore, multiple clusters may be configured. In this case, the configured clusters may be referred to as a cluster set (cluster list). Note that a node belonging to one cluster may also belong to another cluster. In other words, a single node can belong to multiple clusters.

[0163] Clusters can be used by switching between them dynamically or quasi-statically.

[0164] <3-1-2. Specific Examples of Communication Systems> Next, specific examples of communication systems that use communication points will be described. As mentioned above, in this embodiment, a self-free communication system is assumed as an example of a communication system that uses communication points. However, the communication system 1 of this embodiment is not limited to a self-free communication system.

[0165] Figure 6 shows an example of the communication system 1 of this embodiment. The communication system 1 of this embodiment is a wireless communication system comprising a plurality of communication devices (for example, one or more terminal devices 30 and one or more base stations 20). In the following description, the base station 20 may be referred to as BS. Also, in the following description, the terminal device 30 may be referred to as UE.

[0166] The base station 20 includes one or more communication points P (for example, one or more communication antennas). Alternatively, the base station 20 is connected by wire or wireless to one or more communication points P (for example, one or more other base stations 20). Note that the communication points P may be part of the configuration of the base station 20. For example, one or more communication points P may be one or more antennas of the base station 20.

[0167] In the example in Figure 6, base station 20 １ (BS shown in Figure 6) １ ) is communication point P １１ ~Communication points P １ｎ It is connected to base station 20. １ (BS shown in Figure 6) １ ) is communication point P １１ ~Communication points P １ｎ It is equipped with, where n is any integer greater than or equal to 1. Also, in the example in Figure 6, base station 20 ２ (BS shown in Figure 6) ２ ) is communication point P ２１ ~Communication points P ２ｍ It is connected to base station 20. ２ (BS shown in Figure 6) ２ ) is communication point P ２１ ~Communication points P ２ｍ It comprises the following, where m is any integer greater than or equal to 1.

[0168] Each communication point may be controlled by the connected base station 20. For example, communication point P １１ ~Communication points P １ｎ is base station 20 １ It may be controlled by the communication point P. ２１ ~Communication points P２ｍ is base station 20 ２ It may be controlled by [something].

[0169] The terminal device 30 (UE shown in Figure 6) wirelessly connects to one or more communication points P.

[0170] The communication points in this embodiment may operate standalone. In this embodiment, standalone operation refers to the operation in which one or more communication points perform initial access (e.g., random access / wireless connection) with one or more terminal devices 30 without requiring support or notification of information from other communication points. As described above, the communication points may be a single base station 20 or a cluster (e.g., a group of multiple communication points).

[0171] Figures 7 and 8 illustrate standalone operation. For example, a communication point P where a terminal device 30 in an unconnected state (Idle mode / Inactive mode) operates standalone. １ In order to enable connection, the communication point of this embodiment may repeatedly (for example, periodically) transmit an initial access signal that conveys information for initial access. In the example of Figure 7, communication point P １ It is a single base station 20. However, communication point P １ For example, as shown in Figure 8, this could be a cluster (a group consisting of a base station 20 and multiple communication points).

[0172] Here, the information for initial access may be, for example, information for at least one of the following processes performed by the terminal device 30: recognition of the communication point, time-frequency synchronization, and transmission of the first uplink signal. The information for initial access may also be system information for performing random access.

[0173] <3-1-3. Others> The term "communication point" in the following explanation can be replaced with "communication device". Here, the communication device may be the communication point itself, or it may be a device that controls the transmission / reception of radio waves at the communication point. For example, the communication point may be an antenna provided by the base station 20, and the communication device may be the base station 20 that controls that antenna. One or more antennas and the base station 20 that controls those one or more antennas may be considered as a single communication point.

[0174] <3-2. Initial Access Control> The communication points have been described above, but before describing the operation of the communication system 1 of this embodiment in detail, the initial access control (also called the initial access procedure, initial access method, initial access processing, or initial connection processing) will be described.

[0175] <3-2-1. Basic Procedure> First, as a basic procedure for initial access control, an example of the procedure for connecting the terminal device 30 to the base station 20 will be explained. Note that the terms "base station 20" and / or "cell" used in the following explanation can be replaced with "communication point".

[0176] Initial access control is a process that transitions the wireless connection state of the terminal device 30 from an unconnected state to a connected state. In the following description, initial access control may be referred to as the initial access procedure or initial access process.

[0177] Here, the unconnected state refers to, for example, RRC_IDLE and / or RRC_INACTIVE. RRC_IDLE is an idle state in which the terminal device 30 is not connected to any cell, and is also called Idle mode. RRC_INACTIVE is a wireless connection state that indicates an inactive state newly defined in NR, and is also called Inactive mode. In RRC_INACTIVE, the RRC connection itself is not established between the terminal device 30 and the base station 20, but the terminal device 30 and the base station 20 may maintain the states they each hold for some UE contexts. The terminal device 30 and the base station 20 may use the UE contexts they have held to expedite the transition of the terminal device 30 back to the Connected state. Note that the unconnected state may include Lightning mode. The connected state is, for example, RRC_CONNECTED. RRC_CONNECTED is a connected state in which the terminal device 30 has established a connection with a specific cell (for example, Primary Cell), and is also called CONNECTED mode.

[0178] Figure 9 is a sequence diagram showing an example of the initial access process. The initial access process will be explained below with reference to Figure 9.

[0179] An unconnected terminal device 30 performs a cell selection procedure (cell search). The cell selection procedure (cell search) is a procedure for the UE (User Equipment) to detect the PCI (Physical Cell ID) of the cell and obtain time and frequency synchronization. The cell search in this embodiment includes the steps of detecting the synchronization signal and decoding the 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 (signal / information / channel) consisting of a PBCH, a PSS (Primary Synchronization Signal), and a SSS (Secondary Synchronization Signal). The terminal device 30 detects the cell's synchronization signal (SS: Synchronization Signal) (step S12).

[0180] The terminal device 30 synchronizes the cell and the downlink based on the detected synchronization signal. After the downlink synchronization is established, the terminal device 30 attempts to decode the PBCH and obtains the MIB (Master Information Block), which is part of the system information (step S13).

[0181] System information is information that notifies the settings of the cell transmitting the system information. System information may be information common to all terminal devices 30 belonging to the cell. System information may also be information specific to the cell. System information includes, for example, information regarding access to the cell, information regarding cell selection, information regarding other RATs and other systems. System information includes MIB (Master Information Block) and SIB (System Information Block). MIB is information necessary to receive SIBs, etc., and is information of a fixed payload size notified by PBCH. MIB includes a part of the system frame number, information on the subcarrier spacing of predetermined information (e.g., SIB1, Msg.2 / Msg.4 for initial connection, paging, and broadcast SI messages), subcarrier offset information, DMRS type A location information, PDCCH settings for at least SIB1, cell connection prohibited (cell barred) information, in-frequency reselection information, etc. SIB is system information other than MIB, and is broadcast via PDSCH (Physical Downlink Shared Channel).

[0182] In this embodiment, system information is classified into system information SI1, system information SI2, and system information SI3. System information SI1 and system information SI2 include information related to cell access, information related to the acquisition of other system information, and information related to cell selection. The information included in the MIB is system information SI1. Furthermore, the information included in SIB1 of the SIB is system information SI2 (for example, Remaining Minimum SI). The remaining system information (Other SI) is system information SI3.

[0183] In NR, system information is also broadcast from the NR cell. The physical channel carrying the system information may be transmitted via a slot or a minislot. A minislot is defined as having fewer symbols than a slot. By transmitting the physical channel carrying the system information via a minislot, the time required for beam sweeping is reduced, thereby decreasing overhead. In the case of NR, system information SI1 is transmitted via the NR-PBCH, and system information SI2 is transmitted via a physical channel different from the NR-PBCH.

[0184] The terminal device 30 acquires system information SI2 based on MIB (i.e., system information SI1) (step S14). As described above, system information SI2 is composed of SIB1 and SIB2.

[0185] SIB1 contains cell access restriction information and scheduling information for system information other than SIB1. If it is NR, SIB1 includes information about cell selection (e.g., cellSelectionInfo), information related to cell access (e.g., cellAccessRelatedInfo), information about connection establishment failure control (e.g., connEstFailureControl), scheduling information for system information other than SIB1 (e.g., si-SchedulingInfo), serving cell settings, etc. Serving cell settings include cell-specific parameters, such as downlink settings, uplink settings, and TDD setting information. Uplink settings include RACH settings, etc. If it is LTE, SIB1 includes cell access information, cell selection information, maximum uplink transmit power information, TDD setting information, system information period, system information mapping information, and SI (System Information) window length, etc.

[0186] Furthermore, if it is NR, SIB2 includes cell reselection information (e.g., cellReselectionInfoCommon) and cell reselection serving frequency information (e.g., cellReselectionServingFreqInfo). If it is LTE, SIB2 includes connection prohibition information, cell-common radio resource configuration information (radioResourceConfigCommon), uplink carrier information, etc. The cell-common radio resource configuration information includes cell-common PRACH (Physical Random Access Channel) and RACH (Random Access Channel) configuration information.

[0187] Furthermore, if the terminal device 30 is unable to obtain the system information necessary to establish the link, the terminal device 30 determines that access to that cell is prohibited. For example, if the system information SI1 cannot be obtained, the terminal device 30 determines that access to that cell is prohibited. In this case, the terminal device 30 terminates the initial access process.

[0188] If system information is obtained, the terminal device 30 executes a Random Access Procedure based on the system information SI1 and / or system information SI2 (steps S15 to S18). The Random Access Procedure is sometimes referred to as the RACH Procedure (Random Access Channel Procedure) or the RA Procedure (RA Procedure).

[0189] The random access procedure includes the steps of sending a random access preamble (step S15), receiving a random access response (step S16), sending Message 3 (step S17), and receiving a contention resolution (step S17).

[0190] First, the terminal device 30 selects a predetermined PRACH (Physical Random Access Channel) preamble and transmits it to the base station 20 (step S15). Next, the terminal device 30 receives a PDSCH (Physical Downlink Shared Channel) containing a random access response corresponding to the PRACH preamble (step S16). Next, the terminal device 30 transmits a PUSCH containing message 3 using the resources scheduled by the random access response grant included in the random access response (step S17). Finally, the terminal device 30 receives a PDSCH containing collision resolution corresponding to the PUSCH (step S18).

[0191] Message 3 includes an RRC (Radio Resource Control) message requesting an RRC connection. Conflict resolution includes an RRC message for RRC connection setup. When terminal device 30 receives the RRC message for RRC connection setup, it performs an RRC connection operation and transitions from the RRC idle state to the RRC connected state. After transitioning to the RRC connected state, terminal device 30 sends an RRC message to base station 20 indicating completion of RRC connection setup. Through this series of operations, terminal device 30 can connect with base station 20.

[0192] The random access preamble is sometimes referred to as message 1, the random access response as message 2, the collision resolution message as message 4, and the RRC connection setup completion message as message 5.

[0193] After all steps of the random access procedure are completed, the terminal device 30 can transition to a state where it is connected to the cell (connected state).

[0194] The random access procedure shown in Figure 9 is sometimes referred to as a four-step random access procedure (four-step RACH procedure). On the other hand, a random access procedure in which the terminal device 30 transmits a message 3 along with the transmission of a random access preamble, and the base station 20 transmits a random access response and contention resolution in response, is sometimes referred to as a two-step random access procedure (two-step RACH procedure).

[0195] <3-2-2. Random Access Procedures> Next, random access procedures will be explained in detail.

[0196] Random access procedures are performed for purposes such as "RRC connection setup" from an idle state to a connected (or inactive) state, and "state transition requests" from an inactive state to a connected state. Random access procedures are also used for "scheduling requests" to request resources for uplink data transmission, and "timing advance adjustments" to adjust uplink synchronization. In addition, random access procedures are performed in cases such as "on-demand SI requests" to request system information that has not been transmitted, "beam recovery" to restore a broken beam connection, and "handover" to switch connected cells.

[0197] "RRC connection setup" is an operation performed when the terminal device 30 connects to the base station 20 in response to traffic generation or other events. Specifically, it is an operation in which the base station 20 passes connection information (e.g., UE context) to the terminal device 30. The UE context is managed by predetermined communication device identification information (e.g., C-RNTI) instructed by the base station 20. After completing this operation, the terminal device 30 transitions from an idle state to an inactive state, or from an idle state to a connected state.

[0198] A "state transition request" is an operation in which the terminal device 30 requests a state transition from an inactive state to a connected state in response to the occurrence of traffic or other events. By transitioning to the connected state, the terminal device 30 can send and receive unicast data with the base station 20.

[0199] A "scheduling request" is an operation in which the terminal device 30 requests resources for uplink data transmission in response to traffic generation or other events. After successfully receiving this scheduling request, the base station 20 allocates PUSCH resources to the communication device. Note that scheduling requests can also be made via PUCCH.

[0200] "Timing advance adjustment" is an operation to adjust for the frame errors between the downlink and uplink caused by propagation delay. The terminal device 30 transmits PRACH (Physical Random Access Channel) at the adjusted timing in the downlink frame. This allows the base station 20 to recognize the propagation delay with the terminal device 30 and to instruct the terminal device 30 of the timing advance value in a message 2 or the like.

[0201] An "on-demand SI request" is an operation that requests the base station 20 to transmit system information when the terminal device 30 needs system information that has not been transmitted for reasons such as overhead of system information.

[0202] "Beam recovery" is an operation that requests recovery when communication quality deteriorates after a beam has been established due to the movement of the terminal device 30 or the interruption of the communication path by other objects. Upon receiving this request, the base station 20 attempts to connect with the terminal device 30 using a different beam.

[0203] "Handover" is the operation of switching the connection from the cell to which the terminal device 30 is connected (serving cell) to an adjacent cell (neighbor cell) due to changes in the radio wave environment, such as the movement of the terminal device 30. When the terminal device 30 receives a handover command from the base station 20, it requests a connection to the neighbor cell specified by the handover command.

[0204] Random access procedures include contention-based random access procedures and non-contention-based random access procedures.

[0205] The random access procedure described below assumes that the RAT supported by communication system 1 is LTE. However, the random access procedure described below is also applicable when the RAT supported by communication system 1 is not LTE. For example, the random access procedure described below is also applicable when the RAT supported by communication system 1 is 5G, B5G, 6G, or a later generation RAT.

[0206] The following describes collision-based random access procedures and non-collision-based random access procedures in detail.

[0207] <Collision-Based Random Access Procedures> First, let's explain collision-based random access procedures.

[0208] A collision-based random access procedure is a random access procedure initiated by the terminal device 30. Figure 10 shows a diagram of the collision-based random access procedure. As shown in Figure 10, the collision-based random access procedure is a four-step procedure that begins with the transmission of a random access preamble from the terminal device 30. The collision-based random access procedure includes the steps of transmitting a random access preamble (Message 1), receiving a random access response (Message 2), transmitting a message (Message 3), and receiving a conflict resolution message (Message 4).

[0209] First, the terminal device 30 randomly selects a preamble sequence to use from a predetermined set of preamble sequences. Then, the terminal device 30 sends a message containing the selected preamble sequence (Message 1: Random Access Preamble) to the connected base station 20 (step S21). The random access preamble is transmitted using PRACH.

[0210] When base station 20 receives a random access preamble, it sends a random access response (Message 2) to terminal device 30. This random access response is transmitted, for example, using a PDSCH. Terminal device 30 receives the random access response (Message 2) sent from base station 20 (step S22). The random access response includes one or more random access preambles that base station 20 received, and the UL (Uplink) resource (hereinafter referred to as the uplink grant) corresponding to the random access preamble. The random access response also includes TC-RNTI (Temporary Cell Radio Network Temporary Identifier), which is a unique identifier for terminal device 30 that base station 20 has temporarily assigned to terminal device 30.

[0211] When terminal device 30 receives a random access response from base station 20, it determines whether the received information includes the random access preamble transmitted in step S21. If the random access preamble is included, terminal device 30 extracts the uplink grant corresponding to the random access preamble transmitted in step S21 from among the uplink grants included in the random access response. Then, terminal device 30 uses the resources scheduled by the extracted uplink grant to send a UL message (Message 3: Scheduled Transmission) (step S23). The message (Message 3) is sent using PUSCH. The message (Message 3) includes an RRC message for an RRC (Radio Resource Control) connection request. The message (Message 3) also includes the identifier of terminal device 30.

[0212] In a collision-based random access procedure, a random access preamble randomly selected by terminal device 30 is used in the procedure. Therefore, it is possible that at the same time that terminal device 30 transmits a random access preamble, another terminal device 30 may transmit the same random access preamble to the base station 20. In this case, the base station 20 recognizes which terminal devices have a preamble conflict by receiving the identifier transmitted by terminal device 30 in step S23 and resolves the conflict. The base station 20 sends a contention resolution message (Message 4) to the terminal device 30 selected by the conflict resolution. The contention resolution message (Message 4) includes the identifier transmitted by terminal device 30 in step S23. The contention resolution message (Message 4) also includes an RRC message for RRC connection setup. Terminal device 30 receives the contention resolution message (Message 4) transmitted from the base station 20 (step S24).

[0213] The terminal device 30 compares the identifier transmitted in step S23 with the identifier received in step S24. If the identifiers do not match, the terminal device 30 restarts the random access procedure from step S21. If the identifiers match, the terminal device 30 performs an RRC connection operation and transitions from the idle state (RRC_IDLE) to the connected state (RRC_CONNECTED). The terminal device 30 uses the TC-RNTI acquired in step S22 as the C-RNTI (Cell Radio Network Temporary Identifier) ​​for subsequent communications. After transitioning to the connected state, the terminal device 30 sends an RRC message to the base station 20 indicating that the RRC connection setup is complete. This message indicating the completion of the RRC connection setup is also called message 5. Through this series of operations, the terminal device 30 connects with the base station 20.

[0214] Note that the collision-based random access procedure shown in Figure 10 is a four-step random access procedure (4-step RACH). However, the communication system 1 can also support a two-step random access procedure (2-step RACH) as a collision-based random access procedure. For example, the terminal device 30 transmits the message shown in step S23 (Message 3) along with the random access preamble. The base station 20 then transmits a random access response (Message 2) and a conflict resolution (Message 4) in response. Since the random access procedure is completed in two steps, the terminal device 30 can quickly connect to the base station 20.

[0215] Note that Message 1 may be written as "Msg1" or "Msg.1". Message 2 may be written as "Msg2" or "Msg.2". Message 3 may be written as "Msg3" or "Msg.3". Message 4 may be written as "Msg4" or "Msg.4".

[0216] <Non-collision-based random access procedures> Next, we will explain non-collision-based random access procedures.

[0217] The non-collision-based random access procedure is a random access procedure initiated by the base station 20. Figure 11 shows a diagram of the non-collision-based random access procedure. The non-collision-based random access procedure is a three-step procedure that begins with the transmission of a random access preamble assignment from the base station 20. The non-collision-based random access procedure includes the steps of receiving a random access preamble assignment (Message 0), transmitting a random access preamble (Message 1), and receiving a random access response (Message 2).

[0218] In collision-based random access procedures, terminal device 30 randomly selects a preamble sequence. However, in non-collision-based random access procedures, base station 20 assigns a specific random access preamble to terminal device 30. Terminal device 30 receives a random access preamble assignment (Message 0: RA Preamble Assignment) from base station 20 (step S31).

[0219] The terminal device 30 performs random access to the base station 20 using the random access preamble assigned in step S31. That is, the terminal device 30 transmits the assigned random access preamble (Message 1: Random Access Preamble) to the base station 20 using PRACH (step S32).

[0220] The base station 20 receives a random access preamble (Message 1) from the terminal device 30. Then, the base station 20 sends a random access response (Message 2) to the terminal device 30 for the random access preamble (step S33). The random access response includes, for example, information about the uplink grant corresponding to the received random access preamble. When the terminal device 30 receives the random access response (Message 2), it performs an RRC connection operation and transitions from the idle state (RRC_IDLE) to the connected state (RRC_CONNECTED).

[0221] Thus, in a collision-free random access procedure, the base station 20 schedules the random access preamble, making preamble collisions less likely.

[0222] Note that Message 0 may be written as "Msg0" or "Msg.0". Message 1 may be written as "Msg1" or "Msg.1". Message 2 may be written as "Msg2" or "Msg.2".

[0223] <3-2-3. Random Access Procedure for NR> The above describes the random access procedure assuming that the RAT supported by communication system 1 is LTE. Note that the above random access procedure is also applicable to RATs other than LTE. Below, as an example, the random access procedure assuming that the RAT supported by communication system 1 is NR (5G) will be described in detail.

[0224] <Random Access Procedure for NR> The following description details each of the four steps related to Message 1 to Message 4 shown in Figure 10 or Figure 11. The step for Message 1 corresponds to step S21 shown in Figure 10 or step S32 shown in Figure 11. The step for Message 2 corresponds to step S22 shown in Figure 10 or step S33 shown in Figure 11. The step for Message 3 corresponds to step S23 shown in Figure 10. The step for Message 4 corresponds to step S24 shown in Figure 10.

[0225] NR Random Access Preamble (Message 1) In NR, PRACH is called NR-PRACH (NR Physical Random Access Channel). NR-PRACH is constructed using Zadoff-Chu sequences. In NR, multiple preamble formats are defined as the format of NR-PRACH. The preamble format is defined by a combination of parameters such as the subcarrier spacing of the PRACH, transmission bandwidth, sequence length, number of symbols used for transmission, transmission repetitions, CP (Cyclic Prefix) length, and guard period length. The types of NR-PRACH preamble sequences are numbered. The number of the type of preamble sequence is called the preamble index.

[0226] In NR, settings related to NR-PRACH are configured for idle terminal devices 30 using system information. Furthermore, settings related to NR-PRACH are configured for connected terminal devices 30 using dedicated RRC signaling.

[0227] Terminal device 30 transmits NR-PRACH using a physical resource (NR-PRACH Occasion) that can transmit NR-PRACH. The physical resource is indicated by the settings related to NR-PRACH. Terminal device 30 selects one of the physical resources and transmits NR-PRACH. Furthermore, if terminal device 30 is connected, terminal device 30 transmits NR-PRACH using an NR-PRACH resource. An NR-PRACH resource is a combination of the NR-PRACH preamble and its physical resource. Base station 20 can instruct terminal device 30 on the NR-PRACH resource.

[0228] NR-PRACH is also transmitted when the random access procedure fails. When retransmitting NR-PRACH, terminal device 30 waits for a waiting period calculated from the backoff value (backoff indicator, BI) before transmitting NR-PRACH. The backoff value may vary depending on the terminal category of terminal device 30 and the priority of the traffic that occurred. In this case, multiple backoff values ​​are notified, and terminal device 30 selects the backoff value to use according to priority. Also, when retransmitting NR-PRACH, terminal device 30 increases the transmission power of NR-PRACH compared to the initial transmission. This procedure is called power ramping.

[0229] NR Random Access Response (Message 2) NR random access responses are transmitted using the NR-PDSCH (NR Physical Downlink Shared Channel). The NR-PDSCH containing the random access response is scheduled by the NR-PDCCH (NR Physical Downlink Control Channel), which has its CRC (Cyclic Redundancy Check) scrambled by the RA-RNTI (Random Access Radio Network Temporary Identifier). The NR-PDCCH is transmitted in the CORESET (Control Resource Set). The NR-PDCCH with its CRC scrambled by the RA-RNTI is placed in the CSS (Common Search Space) of the Type1-PDCCH CSS set. The value of the RA-RNTI is determined based on the transmission resource of the NR-PRACH corresponding to that random access response. The transmission resources for NR-PRACH are, for example, time resources (slots or subframes) and frequency resources (resource blocks). NR-PDCCH may be placed in a search space associated with an NR-PRACH linked to a random access response. Specifically, the search space where NR-PDCCH is placed is configured in association with the NR-PRACH preamble and / or the physical resource from which the NR-PRACH was transmitted. The search space where NR-PDCCH is placed is configured in association with the preamble index and / or the index of the physical resource. NR-PDCCH resides in NR-SS (NR Synchronization signal) and QCL (Quasi co-located).

[0230] The NR random access response contains MAC (Medium Access Control) information. The NR random access response includes at least the uplink grant for sending NR message 3, the timing advance value used to adjust uplink frame synchronization, and the TC-RNTI value. The NR random access response also includes the PRACH index used for the NR-PRACH transmission corresponding to that random access response. Furthermore, the NR random access response includes information about the backoff used to wait for PRACH transmission.

[0231] The base station 20 transmits a random access response in NR-PDSCH format. The terminal device 30 determines whether the transmission of the random access preamble was successful based on the information contained in the random access response. If it determines that the transmission of the random access preamble was successful, the terminal device 30 performs the transmission process of NR message 3 (Message 3) according to the information contained in the random access response. On the other hand, if the transmission of the random access preamble fails, the terminal device 30 determines that the random access procedure has failed and performs the retransmission process of NR-PRACH.

[0232] Furthermore, the NR's random access response may include multiple uplink grants for sending the NR's message 3. The terminal device 30 can select one resource from the multiple uplink grants to send message 3. This mitigates collisions in sending the NR's message 3 when different terminal devices 30 receive the same NR's random access response. As a result, the communication system 1 can provide a more stable random access procedure.

[0233] NR Message 3 NR Message 3 is transmitted via NR-PUSCH (NR Physical Uplink Shared Channel). NR-PUSCH is transmitted using the resources indicated by the random access response. NR Message 3 contains an RRC connection request message. The format of NR-PUSCH is indicated by parameters included in the system information. For example, parameters determine whether to use OFDM (Orthogonal Frequency Division Multiplexing) or DFT-s-OFDM (Discrete Fourier Transform Spread OFDM) as the format for NR-PUSCH.

[0234] If NR message 3 is successfully received, base station 20 proceeds to the process of sending conflict resolution (Message 4). On the other hand, if NR message 3 is not successfully received, base station 20 attempts to receive NR message 3 again for at least a predetermined period of time.

[0235] Another example of instructions for retransmitting message 3 and the transmission resources involved is the instruction by NR-PDCCH used for instructing the retransmission of message 3. This NR-PDCCH is an uplink grant. The DCI (Downlink Control Information) of this NR-PDCCH instructs the resources for retransmitting message 3. The terminal device 30 retransmits message 3 based on the instructions from the uplink grant.

[0236] If the NR conflict resolution is not successfully received within a predetermined period, the terminal device 30 considers the random access procedure to have failed and performs the NR-PRACH retransmission process. The transmission beam of the terminal device 30 used to retransmit the NR message 3 may be different from the transmission beam of the terminal device 30 used to initially transmit the message 3. If neither the NR conflict resolution instruction nor the instruction to retransmit message 3 is received within the predetermined period, the terminal device 30 considers the random access procedure to have failed and performs the NR-PRACH retransmission process. This predetermined period is set, for example, by system information.

[0237] NR Conflict Resolution (Message 4) NR conflict resolution is transmitted using NR-PDSCH. NR-PDSCH containing conflict resolution is scheduled by NR-PDCCH with CRC scrambled by TC-RNTI or C-RNTI. NR-PDCCH with CRC scrambled by TC-RNTI is placed in the CSS of Type1-PDCCH CSS set. NR-PDCCH may also be placed in USS (User equipment specific Search Space). NR-PDCCH may also be placed in other CSSs.

[0238] If terminal device 30 successfully receives the NR-PDSCH including the conflict resolution, it sends an acknowledgment (ACK) to base station 20. Thereafter, terminal device 30 considers the random access procedure to have been successful and transitions to the connected state (RRC_CONNECTED). On the other hand, if base station 20 receives a negative acknowledgment (NACK) for the NR-PDSCH from terminal device 30, or if there is no response, base station 20 retransmits the NR-PDSCH including the conflict resolution. If terminal device 30 fails to receive the NR conflict resolution (Message 4) within a predetermined period, it considers the random access procedure to have failed and retransmits the random access preamble (Message 1).

[0239] <NR's Two-Step Random Access Procedure> Next, an example of NR's two-step random access procedure (hereinafter referred to as the two-step random access procedure) is shown.

[0240] Figure 12 shows a two-step random access procedure. The two-step random access procedure consists of two steps: message A (step S41) and message B (step S42). For example, message A includes message 1 (preamble) and message 3 of a conventional four-step random access procedure (4-STEP RACH procedure), and message B includes message 2 and message 4 of a conventional four-step random access procedure. Also, for example, message A consists of a preamble (also called PRACH) and PUSCH, and message B consists of PDSCH.

[0241] By using a two-step random access procedure, it becomes possible to complete the random access procedure with lower latency compared to the conventional four-step random access procedure.

[0242] The preamble and PUSCH included in message A may be configured in conjunction with their respective transmission resources, or they may be configured as independent resources.

[0243] When transmission resources are associated and configured, for example, when the transmission resource for the preamble is determined, a unique or multiple candidate transmission resource for PUSCH is determined. As an example, the time and frequency offset between the PRACH occasion preamble and the PUSCH occasion is defined by a single value. As another example, the time and frequency offset between the PRACH occasion preamble and the PUSCH occasion may be defined by different values ​​for each preamble. The offset values ​​may be determined by the specification, or the base station 20 may set them quasi-statically. As an example of the time and frequency offset values, they may be defined by a predetermined frequency. For example, in an unlicensed band (e.g., 5GHz band, band 45), the time offset value can be set to 0 or a value close to 0. This makes it possible to omit LBT (Listen Before Talk) before transmitting PUSCH.

[0244] On the other hand, if configured with independent resources, the transmission resources for the preamble and PUSCH may be determined by the specifications, the resources may be configured quasi-statically by the base station 20, or the resources may be determined from other information. Other information may include, for example, slot format information (e.g., Slot Format Indicator), BWP (Band Width Part) information, preamble transmission resource information, slot index, and resource block index. Also, if configured with independent resources, the association between the preamble and PUSCH constituting a single message A may be notified to the base station 20 by the payload of the PUSCH or the UCI contained in the PUSCH, or by the transmission physical parameters of the PUSCH (e.g., the scramble sequence of the PUSCH, the DMRS sequence and / or pattern, or the transmission antenna port of the PUSCH).

[0245] Furthermore, the method for configuring the preamble and PUSCH transmission resources may be switched between being configured as linked resources and being configured as independent resources. For example, the independent resource configuration may apply to licensed bands, while the linked resource configuration may apply to unlicensed bands.

[0246] The above describes a random access procedure assuming that the RAT supported by communication system 1 is NR. Note that the above random access procedure is also applicable to RATs other than NR (e.g., 5G, B5G, or 6G, or later generations of RATs). Furthermore, the above random access procedure is also applicable to cell-free communication.

[0247] <3-2-4. Initial Access Control in Self-Free Communication> The initial access control (initial access processing) described above is also applicable to self-free communication. The initial access control (initial access processing) in self-free communication will be explained below.

[0248] In initial access control (initial access processing), the terminal device 30 receives at least a first signal, a first broadcast information, a second signal, and a second broadcast information from the communication point. Based on these signals and information, the terminal device 30 performs initial access processing.

[0249] The first signal, the first broadcast information, the second signal, and the second broadcast information may be signals / information used in conventional standards (hereinafter also referred to as the first initial access signal), or signals / information with a different configuration from those used in conventional standards (hereinafter also referred to as the second initial access signal). Here, the conventional standard may be a 5G (NR) communication standard, or a communication standard from a generation prior to 5G (for example, 4G (LTE)).

[0250] The first signal, the first broadcast information, the second signal, and the second broadcast information will be explained below. Note that the following information (the first signal, the first broadcast information, the second signal, and the second broadcast information) is applicable to communications other than cell-free communications. Furthermore, the following information (the first signal, the first broadcast information, and the second signal) is also applicable to conventional cellular communications (for example, 4G (LTE) and / or 5G (NR)).

[0251] <First Signal> First, let me explain the first signal.

[0252] The first signal may be a predetermined signal detected by the terminal device 30 before receiving the first broadcast information. Alternatively, the first signal may be a signal for the terminal device 30 to perform at least one of the following: time synchronization, frequency synchronization, cell ID recognition, recognition of the resource for the first broadcast information, and reception processing of the first broadcast information.

[0253] The first signal may be a synchronization signal having the same function, purpose, and configuration as, for example, the PSS and / or SSS in 5G (NR) and 4G (LTE). Alternatively, the first signal may be a synchronization signal having the same function, purpose, and configuration as, for example, the PSS and / or SSS in 5G (NR) and 4G (LTE). Of course, the first signal is not limited to these signals.

[0254] The first signal is transmitted from a predetermined communication point among one or more communication points. In this case, the first signal may be transmitted from multiple communication points. For example, the first signal may be transmitted from all communication points connected to a base station 20.

[0255] <First piece of information> Next, I will explain the first piece of information.

[0256] The first broadcast information is information that enables the terminal device 30 to perform at least one of the following: perform an initial access and receive the second signal. The first broadcast information does not necessarily have to be transmitted in a single transmission unit, a single resource, or a single channel. The first broadcast information may be transmitted in multiple transmission units, multiple resources, or multiple channels.

[0257] The first broadcast information is, for example, information (or channel) with the same function, purpose, and configuration as a PBCH in 5G. Alternatively, the first broadcast information is, for example, information (or channel) with the same function, purpose, and configuration as a PBCH in 5G. Alternatively, the first broadcast information is information (or channel) with the same function, purpose, and configuration as MIB and / or SIB in 5G (NR) and 4G (LTE). Alternatively, the first broadcast information is, for example, information (or channel) with the same function, purpose, and configuration as MIB and / or SIB in 5G (NR) and 4G (LTE). Of course, the first broadcast information is not limited to this information (or channel).

[0258] (Information included in the first broadcast information) The first broadcast information may include at least one of the following: information relating to the second signal and information relating to the initial access.

[0259] (1) Information concerning the second signal Information concerning the second signal is information necessary for the terminal device 30 to receive the second signal. Information concerning the second signal may be a list of one or more second signals that the terminal device 30 may receive (or should receive). In this case, the second signals included in the list may be all of the second signals transmitted / managed / controlled by the communication point that transmits the first signal and / or the first broadcast information. Alternatively, the second signals included in the list may be a part of the second signals transmitted / managed / controlled by the communication point that transmits the first signal and / or the first broadcast information. In this case, the second signals included in the list may be determined according to the location of the terminal device 30, etc.

[0260] The information regarding the second signal may include, for example, at least one of the pieces of information shown in (D1) to (D4) below.

[0261] (D1) The number of signals that the terminal device 30 may receive or should receive. (D2) Time and frequency resource information. (D3) If the second signal is code-divided multiplexed, information about the code (e.g., code index). (D4) If a scramble code is superimposed on the second signal (e.g., if the second signal is generated based on a scramble code), information about that scramble code.

[0262] Furthermore, the information regarding the second signal may include a list of communication points that can be combined.

[0263] (2) Information regarding initial access Information regarding initial access may be information necessary for the terminal device 30 to perform initial access processing (initial access control) to the communication point. Here, the communication point may be a predetermined base station 20, a predetermined communication point connected to the predetermined base station 20, or a core network controlling the predetermined base station 20. The communication point may also be a communication node associated with (determined based on) the predetermined base station 20, a predetermined communication point, or a predetermined core network.

[0264] Furthermore, information regarding the initial access may be transmitted from each communication point as a second piece of information.

[0265] Information regarding initial access may include, for example, at least one of the following pieces of information: (E1) to (E3).

[0266] (E1) Information necessary for transmitting, selecting, or determining the random access channel (msg1). For example, the information regarding initial access may include information necessary for selecting or determining the random access channel. For example, the information regarding initial access may include information indicating the selectable range of random access preambles to be transmitted on the random access channel. The information regarding initial access may also include information regarding time and frequency resources for transmitting the random access channel.

[0267] (E2) Information necessary for receiving the random access response (msg2). For example, information regarding the initial access may include information necessary for recognizing or detecting the random access response.

[0268] (E3) Information regarding PUSCH (msg3) For example, information regarding initial access may include information regarding information to be transmitted by PUSCH. For example, information regarding initial access may include information regarding the selected communication point and / or information regarding the communication quality for one or more communication points.

[0269] (Other) The first broadcast information is transmitted from a predetermined communication point among one or more communication points. In this case, the first broadcast information may be transmitted from multiple communication points. For example, the first broadcast information may be transmitted from all communication points connected to a base station 20.

[0270] Furthermore, the first broadcast information may be transmitted from the same communication point as the first signal. That is, the QCI (QoS Class Identifier) ​​of the first broadcast information may be recognized as being the same as the QCI of the first signal. For example, when the terminal device 30 demodulates and / or decodes the first broadcast information, it may do so using at least a part of the propagation path characteristics of the first signal.

[0271] The first notification information may be transmitted from a different communication point than the first signal.

[0272] <Second Signal> Next, I will explain the second signal.

[0273] The second signal may be at least one of the following signals (F1) to (F4). Of course, the second signal is not limited to these signals.

[0274] (F1) Reference signal transmitted from a communication point For example, the second signal may be a reference signal transmitted from a communication point. For example, the second signal may be a known reference signal that the terminal device 30 can recognize as being transmitted from a predetermined communication point. Here, the QCI of the second signal may be different from the QCI of the first broadcast information and / or the QCI of the first signal.

[0275] (F2) A signal for measuring the communication quality of a communication point The second signal may be a signal for measuring (detecting, recognizing, or actually measuring) the communication quality of a communication point. For example, the second signal may be a known signal used in initial access control to select a communication point and / or report on the communication quality.

[0276] Here, the communication quality may be RSRP, RSRQ, RSSI, SINR, SNR, SIR, CSI, CQI, PMI, or RI.

[0277] RSRP (Reference Signal Received Power) indicates the power level of a reference signal received from a specific communication point. This value shows how strongly the receiver is receiving the reference signal. RSRP is used, for example, to evaluate the quality of communication.

[0278] RSRQ (Reference Signal Received Quality) is an index that indicates the level of noise relative to RSRP. In other words, RSRQ represents the ratio of signal strength to noise level. RSRQ is used, for example, to evaluate signal quality.

[0279] RSSI (Received Signal Strength Indicator) is a value that indicates the strength of a received signal. RSSI is used, for example, to measure the strength of a wireless communication signal. However, unlike other indicators, RSSI does not contain information about the quality of a particular signal.

[0280] SINR (Signal-to-Interference-plus-Noise Ratio) indicates the ratio of signal to interference / noise.

[0281] SNR (Signal-to-Noise Ratio) indicates the ratio of signal to noise.

[0282] SIR (Signal-to-Interference Ratio) indicates the ratio of signal to interference. SIR is used to evaluate the quality of communications.

[0283] Channel State Information (CSI) is information that indicates the state of a radio propagation path. CSI is used to understand the characteristics or quality of a communication path.

[0284] The Channel Quality Indicator (CQI) is an indicator of the quality of a radio propagation path. The CQI corresponds to the frequency utilization efficiency according to a given modulation scheme and the number of MIMO layers.

[0285] The PMI (Precoding Matrix Indicator) indicates a matrix for effectively transmitting signals between transmitting antennas in MIMO (Multiple-Input Multiple-Output) communication.

[0286] RI (Rank Indicator) indicates the number of MIMO layers in MIMO communication (e.g., rank number, number of transmitting antennas, or available spatial multiplexing).

[0287] (F3) A second signal for measuring the characteristics between communication points may be a signal for measuring (detecting, recognizing, measuring, or reporting) the relative characteristics (quality, or features) between communication points. The communication quality of each communication point may be measured using the second signal. The relative characteristics between communication points may be used to report in initial access control.

[0288] Furthermore, the relative characteristics between communication points may include differences in propagation characteristics between communication points. Differences in propagation characteristics between communication points may also be information indicating differences in propagation characteristics between communication points, or changes in propagation characteristics between communication points. Differences in propagation characteristics between communication points may include, for example, at least one of the following: Differences in received power (e.g., RSRP, path loss, or SNR) between communication points Differences in delay time (e.g., arrival time, or delay dispersion) between communication points Differences in Doppler frequency between communication points Differences in phase between communication points Differences in the above-mentioned communication quality between communication points

[0289] In determining the differences in propagation characteristics between communication points, the reference communication point may be predetermined or defined, or it may be determined by a predetermined criterion. For example, the reference communication point may be any of the following: • The communication point with the smallest or largest value associated with the communication point (e.g., communication point ID (index)) • The communication point with the largest or smallest received power • The communication point with the fastest or slowest arrival time • The communication point with the best or worst communication quality for the communication point

[0290] Furthermore, the reference communication point may be determined based on a second signal transmitted by the communication point (for example, the transmission resource for the second signal, or an ID indicating the second signal). Alternatively, the reference communication point may be set by the first broadcast information or the second broadcast information.

[0291] (F4) The second synchronization signal transmitted from the communication point may be a synchronization signal having the same function, purpose, and configuration as, for example, the PSS and / or SSS in 5G. Alternatively, the second signal may be a synchronization signal having the same function, purpose, and configuration as, for example, the PSS and / or SSS in 5G.

[0292] <Second piece of information> Next, I will explain the second piece of information.

[0293] The second broadcast information is information broadcast from the communication point and is different from the first broadcast information (or channel). For example, the first broadcast information may be an MIB and the second broadcast information may be an SIB. Alternatively, the first broadcast information may be SIB1 and the second broadcast information may be an SIB other than SIB1. Alternatively, the first broadcast information may be an MIB and SIB1 and the second broadcast information may be an SIB other than SIB1. Note that the second broadcast information does not have to be information transmitted in one transmission unit, one resource, or one channel. The first broadcast information may be transmitted in multiple transmission units, multiple resources, or multiple channels.

[0294] The second broadcast information is, for example, information (or channel) with the same function, purpose, and configuration as a PBCH in 5G. Alternatively, the second broadcast information is, for example, information (or channel) with the same function, purpose, and configuration as a PBCH in 5G. Alternatively, the second broadcast information is information (or channel) with the same function, purpose, and configuration as MIB and / or SIB in 5G (NR) and 4G (LTE). Alternatively, the second broadcast information is, for example, information (or channel) with the same function, purpose, and configuration as MIB and / or SIB in 5G (NR) and 4G (LTE). Of course, the second broadcast information is not limited to this information (or channel).

[0295] <3-3. Conventional Synchronization Processing> Having described initial access control above, before describing in detail the operation of the communication system 1 of this embodiment, we will explain conventional synchronization processing.

[0296] Figure 13 is a diagram illustrating the conventional synchronization process. In a conventional 5G (NR) communication system, SSB is transmitted repeatedly without interruption at a fixed period T (T = 20 ms, 40 ms, 80 ms, 160 ms). When the terminal device 30 detects PSS / SSS by blind search, it correlates the received signal, which is a superposition of signals at intervals such as 20 ms, with the pre-defined PSS / SSS standby signal component (a component modulated with pre-owned PSS / SSS information). The terminal device 30 then determines the time synchronization point.

[0297] In this case, the more times the received signals are superimposed, the greater the received gain of the PSS / SSS components. Therefore, the more times the received signals are superimposed, the higher the time synchronization accuracy. In particular, in use cases where the available bandwidth and / or transmit power are limited (e.g., NTN or RedCap), time synchronization accuracy is ensured by increasing the number of repeated SSB transmissions.

[0298] Furthermore, if the transmission period is set to a large period (for example, T = 40 ms, 80 ms, 160 ms, ...), the effect of improving synchronization accuracy through superposition becomes smaller due to various factors (for example, differences in clock accuracy between the base station and terminal equipment, and / or channel fluctuations). For this reason, the maximum period T currently specified in 3GPP is 160 ms, and transmission at periods longer than that is not envisioned.

[0299] <3-4. Supplement> In this embodiment, the conventional methods are based on the 3GPP technical specifications TS 38.331 and TS 36.331. TS 38.331 and TS 36.331 define specifications for SI (System Information). TS 38.331 and TS 36.331 state that OSI (Other SIBs) are indicated by SIB1 and transmitted (on demand). Here, OSI refers to SIB2 and subsequent SIBs. Furthermore, TS 38.331 and TS 36.331 stipulate that SIB1 contains information such as SIB mapping information, SI message, periodicity, and SI-window size, and that after an RRC connection is established, changes to the SIB configuration are notified via the RRC.

[0300] <<4. Operation of the Communication System>> Based on the above, the operation of communication system 1 will be explained in detail.

[0301] <4-1. Explanation of Terms> First, we will explain some terms that are prerequisites for describing the operation.

[0302] (First System Information) In this embodiment, the first system information refers to important system information such as scheduling information for downlink / uplink signals. In a conventional cellular communication system (for example, an LTE system or an NR system), the first system information is the system information notified by SIB1 or the like.

[0303] (First Uplink Signal) In this embodiment, the first uplink signal refers to the uplink signal that the terminal device 30 initially transmits to the communication point when performing wireless communication with the communication point. In a conventional cellular communication system (for example, an LTE system or an NR system), the first uplink signal is a signal referred to as PRACH or Msg1.

[0304] (On-Demand Transmission) In this embodiment, on-demand transmission of the first signal and / or first broadcast information means that the communication point transmits the first signal and / or first broadcast information on demand. That is, when a communication point supports on-demand transmission, the communication point does not continuously transmit the first signal and / or first broadcast information repeatedly (for example, periodically) at all times, but rather transmits the first signal and / or first broadcast information repeatedly (for example, periodically) only when requested.

[0305] Specifically, a communication point that supports on-demand communication is basically in a sleep or power-off state and may be activated in response to a trigger signal from a communication device (e.g., terminal device 30 and / or base station 20) or another communication point. The trigger signal is, for example, a WUS (Wake Up Signal) or an UL WUS (Uplink Wake Up Signal). The trigger signal may also be referred to as an initial trigger or excitation signal. Furthermore, even when a communication point that supports on-demand communication is powered on, it may be activated in response to a trigger signal transmitted by a communication device (e.g., terminal device 30 and / or base station 20) for the purpose of performing channel status measurements (e.g., measurement, L1 / L3 measurement). The activated communication point then sets a transmission window (time window) and transmits the first signal and / or the first broadcast information repeatedly (e.g., periodically) during that transmission window. Alternatively, the activated communication point may repeatedly (e.g., periodically) transmit the first signal and / or the first broadcast information until it goes to sleep or is powered off again.

[0306] (On-Demand Signal) In this embodiment, a signal transmitted from a communication point upon request may be referred to as an on-demand signal (or an on-demand first signal). The on-demand signal may be an on-demand first signal or on-demand first broadcast information.

[0307] Here, the on-demand first signal is the first signal transmitted from the communication point upon request. The on-demand first signal may also be referred to as the on-demand first signal. If the first signal is an SSB, the on-demand first signal is an on-demand SSB (hereinafter also referred to as on-demand SSB or OD-SSB). Of course, the on-demand first signal is not limited to an on-demand SSB.

[0308] Furthermore, the on-demand first broadcast information refers to the first broadcast information transmitted from the communication point in response to a request. The on-demand first broadcast information may also be referred to as the on-demand first broadcast information. If the first broadcast information is SIB1, the on-demand first broadcast information is the on-demand SIB1 (hereinafter also referred to as on-demand SIB1 or OD-SIB1). Of course, the on-demand first broadcast information is not limited to on-demand SIB1.

[0309] The on-demand signal is not limited to the on-demand first signal and / or the on-demand first broadcast information. The on-demand signal may be the on-demand second signal or the on-demand second broadcast information. The on-demand second signal is a second signal transmitted from the communication point upon request. The on-demand second broadcast information is second broadcast information transmitted from the communication point upon request.

[0310] (On-Demand Communication Point) In this embodiment, a communication point that supports on-demand communication (a communication point that supports the transmission of on-demand signals) may be referred to as an on-demand communication point. An on-demand communication point may also be called an on-demand cell. An on-demand cell is a cell that supports on-demand communication (a cell that supports the transmission of on-demand signals). An example of an on-demand cell is a Network Energy Saving (NES) cell.

[0311] (Standalone Operation) In this embodiment, standalone operation refers to the operation in which one or more communication points perform initial access with one or more terminal devices 30 without requiring support or notification of information from other communication points. As described above, a communication point may be a single base station 20 or a cluster (for example, a group of multiple communication points).

[0312] (Resources) In this embodiment, resources represent, for example, Frequency, Time, Resource Element (including REG, CCE, CORESET), Resource Block, Bandwidth Part, Component Carrier, Symbol, Sub-Symbol, Slot, Mini-Slot, Subslot, Subframe, Frame, PRACH occasion, Occasion, Code, Multi-access physical resource, Multi-access signature, or Subcarrier Spacing (Numerology).

[0313] (Other) In the following explanations, when providing specific examples, specific values ​​are sometimes given. However, the values ​​may be different from those given in the examples.

[0314] <4-2. Overview of Operation> Next, an overview of the operation of communication system 1 will be explained.

[0315] To achieve high-performance wireless communication, the communication system 1 (for example, the communication point and / or terminal device 30) is required to reduce power consumption and / or interference.

[0316] However, in conventional 5G (NR) communication systems, SSB is transmitted repeatedly without interruption at a fixed period T (T = 20 ms, 40 ms, 80 ms, or 160 ms). To save power and / or reduce interference, it is conceivable to lengthen the transmission period of the synchronization signal and / or broadcast information. However, in this case, the accuracy of time-frequency synchronization at the terminal equipment deteriorates. Also, to save power and / or reduce interference, it is conceivable to make the transmission of the synchronization signal and / or broadcast information on demand. However, in this case, the communication point cannot operate standalone because other communication nodes need to trigger the communication point, or because there is insufficient information that can be included in the SS / PBCH. Therefore, it is difficult to achieve power saving and / or interference avoidance with conventional standards.

[0317] Furthermore, there is a demand to include a lot of information in the PBCH. For example, in order to achieve power saving through on-demand operation, there is a demand to include information about the wake-up signal (WUS) configuration in the PBCH. However, in 5G, the SSB signal configuration is fixed in order to accommodate various use cases. Therefore, conventional standards cannot meet the above requirements.

[0318] Furthermore, there is a demand to provide different SIB1s depending on the use case in order to save power and / or reduce latency. For example, there is a demand to map on-demand SIB1 and conventional SIB1 simultaneously, to change the information included in SIB1, and to change the resource configuration / signal configuration of SIB1. However, conventional PBCH (or MIB) is a signal that notifies information about only one SIB1. Also, conventional standards do not allow changing the signal configuration of SIB1 or to use SIB1 in conjunction with on-demand signals. In other words, conventional synchronization signals and broadcast information do not have flexibility in signal configuration. For this reason, conventional standards cannot meet the above requirements.

[0319] To solve the above problems, in this embodiment, the communication system 1 operates as follows.

[0320] In this embodiment, the communication point groups multiple transmissions of the initial access signal (e.g., SSB) in a first period T1 into a single group (e.g., an SSB group), and transmits this group intermittently. That is, the communication point repeatedly transmits this group at intervals. Since the transmission of a single group is performed at intervals, it is possible to improve power efficiency and / or reduce interference. Moreover, since the initial access signal is transmitted multiple times at once within a single group, the synchronization accuracy of the terminal device 30 is also ensured.

[0321] Furthermore, a communication point may have different broadcast information (e.g., PBCH) for multiple initial access signals included in a single group (e.g., an SSB group). For example, a communication point may set broadcast information for at least one of the multiple initial access signals included in an SSB group that differs in content / resource amount / use case / transmission method from the broadcast information for other initial access signals included in the SSB group G. Furthermore, a communication point may have different broadcast information (e.g., SIB1) associated with multiple initial access signals (e.g., SSB) included in a single group (e.g., an SSB group). By flexibly configuring the broadcast information within a group according to the connection status of the terminal device 30 and the surrounding environment of the communication point, high-performance wireless communication (e.g., low power consumption, low interference, or low latency) can be achieved.

[0322] These processes are performed, for example, by the control unit of the communication point (for example, the control unit 23 of the base station 20 (for example, the transmission control unit 231, the reception control unit 232, the acquisition unit 233, or the state control unit 234)).

[0323] <4-3. Operation of the Communication Point> Next, the operation of the communication point in this embodiment will be described.

[0324] The initial access signal is, for example, a first signal and / or first broadcast information. The initial access signal may include first system information. Here, the first signal and / or first broadcast information is, for example, a signal / information having the same or similar function, purpose, and configuration as an SSB in 5G. For example, the first signal is a signal having the same or similar function, purpose, and configuration as a PSS and / or SSS, and the first broadcast information is information (or channel) having the same or similar function, purpose, and configuration as a PBCH. The first system information is, for example, information having the same or similar function, purpose, and configuration as an SIB1. The first system information may also be, for example, information having the same or similar function, purpose, and configuration as an MIB. The first system information may be part or all of the first broadcast information, or it may be information different from the first broadcast information.

[0325] <4-3-1. Basic Operation of the Communication Point> Figure 14 is a diagram illustrating the operation of the communication point. The communication point of this embodiment has the function of transmitting the initial access signal in a double cycle. For example, the communication point of this embodiment groups multiple (N) transmissions of the initial access signal in the first cycle T1 into one group, and transmits this group in the second cycle T2. Here, N is any integer of 2 or more. Note that a single group does not necessarily have to contain multiple initial access signals. The transmission of one initial access signal may be considered as one group. The above-mentioned or later-mentioned "multiple initial access signals" can be replaced with "one initial access signal" or "one or more initial access signals" as appropriate. Similarly, "multiple transmissions in the first cycle T1" can be replaced with "one transmission in the first cycle T1" or "one or more transmissions in the first cycle T1" as appropriate.

[0326] In this embodiment, this group (a plurality of initial access signals transmitted in a first period T1) is called an SSB group. An SSB group may be identified by the number of repetitions of the initial access signals it contains. In the example in Figure 14, the SSB group (SSB group G shown in Figure 14) consists of four transmissions of SSB in the first period T1. Note that the designation of this group is not limited to an SSB group; for example, it may be called a time-axis window, an SSB window, or an SSB cluster. The initial access signals constituting an SSB group may include signals / information other than SSB. For example, the initial access signals may include SIB1.

[0327] Here, the first period T1 may be, for example, a period defined in a conventional standard (for example, 20 ms, 40 ms, 80 ms, or 160 ms). Of course, the first period T1 is not limited to these, and may be, for example, 5 ms, 10 ms, 15 ms, 25 ms, 30 ms, 35 ms, 45 ms, 50 ms, 55 ms, 60 ms, 65 ms, 70 ms, 75 ms, 85 ms, 90 ms, 95 ms, 100 ms, 105 ms, 110 ms, 115 ms, 120 ms, 125 ms, 130 ms, 135 ms, 140 ms, 145 ms, 150 ms, or 155 ms. Of course, the first period T1 may be shorter than 5 ms or longer than 160 ms. The first period may also be referred to as SSB periodicity 0, SSB periodicity 1, SS periodicity 0, or SS periodicity 1.

[0328] Furthermore, the second period T2 is a period longer than, for example, the time obtained by multiplying the first period T1 by N (time T3 in the example in Figure 14). As mentioned above, N is the number of times the initial access signal is transmitted in one SSB group G. Here, the second period T2 may be a period longer than the maximum value of the SSB transmission period (160 ms) defined in the conventional standard.

[0329] For example, the second period T2 is 320ms, 500ms, 540ms, 1000ms, 1080ms, 1500ms, 2000ms, 2500ms, 3000ms, 3500ms, 4000ms, 4500ms, 5000ms, 6500ms, 7000ms, 7500ms, 8000ms, 8500ms, 9000ms, 9500ms, 10 It may also be 000ms, 15000ms, 20000ms, 25000ms, 30000ms, 35000ms, 40000ms, 45000ms, 50000ms, 60000ms, 65000ms, 70000ms, 75000ms, 80000ms, 85000ms, 90000ms, 95000ms, or 100000ms.

[0330] Of course, the second period T2 is not limited to these, and may be, for example, 160 ms, or a shorter period than 160 ms (for example, 5 ms, 10 ms, 15 ms, 20 ms, 25 ms, 30 ms, 35 ms, 40 ms, 45 ms, 50 ms, 55 ms, 60 ms, 65 ms, 70 ms, 75 ms, 85 ms, 90 ms, 95 ms, 100 ms, 105 ms, 110 ms, 115 ms, 120 ms, 125 ms, 130 ms, 135 ms, 140 ms, 145 ms, 150 ms, or 155 ms). Also, the second period T2 may be longer than 100,000 ms.

[0331] The second period may also be referred to as SSB periodicity 1, SSB periodicity 2, SS periodicity 1, or SS periodicity 2.

[0332] Multiple transmissions of initial access signals in a single SSB group G may be SSB bursts in the conventional 5G (NR) standard, without beamforming / point forming (or beam management, beam steering, or beam focusing). In this case, the terminal device 30 may perform the synchronization superposition described in <3-3. Conventional Synchronization Processing> on an SSB burst basis.

[0333] Furthermore, the communication point may transmit one initial access signal within a single SSB group G as an SSB burst (or burst transmission). In this case, the communication point may set the beam transmission direction to be the same for all initial access signals within the SSB group G. Alternatively, the communication point may complete the beamforming process within a single SSB group G.

[0334] Furthermore, as mentioned above, the second period T2 is longer than, for example, the time obtained by multiplying the first period T1 by N (time T3 in the example in Figure 14). However, the communication point may set the second period T2 to the same time as the time obtained by multiplying the first period T1 by N. In other words, the communication point may set the second period T2 so that the transmission of SSB group G (multiple transmissions of the initial access signal) is repeated continuously rather than intermittently. Figure 15 shows a diagram illustrating the continuous transmission of multiple initial access signals. This allows the communication point to simply and repeatedly transmit the initial access signal, for example, in accordance with conventional standards. Even in this case, it is still possible to define SSB group G, as shown in Figure 15, for example. This is also applicable to changes in the signal configuration shown later.

[0335] Furthermore, the communication point may be set not only for the second period T2 but also for the first period T1. The setting of the first period T1 and / or the second period T2 may be performed quasi-statically or dynamically. Of course, the setting of the first period T1 and / or the second period T2 may be performed statically. The setting of the first period T1 and / or the second period T2 can be performed, for example, by the control unit of the communication point (for example, the transmission control unit 231 of the base station 20).

[0336] <4-3-2. Transmission Period> The first period T1 and the second period T2 do not necessarily have to be fixed periods. The communication point may flexibly change the first period T1 and / or the second period T2, for example, depending on time and / or circumstances. For example, the communication point (e.g., the transmission control unit 231 of the base station 20) may change at least one of the first period T1 and the second period T2 when the first condition is met.

[0337] For example, suppose that when the first condition is not met, the second period T2 is such that transmissions of SSB group G are continuously repeated. In this case, the communication point may change the second period T2 so that transmissions of SSB group G are intermittently repeated when the first condition is met.

[0338] Conversely, suppose that when the first condition is not met, the second period T2 is such that transmissions of SSB group G occur intermittently and repeatedly. In this case, the communication point may change the second period T2 so that transmissions of SSB group G occur continuously and repeatedly when the first condition is met.

[0339] The first condition may consist of one or more conditions, including at least one of the conditions shown below. For example, the first condition may be any of the conditions shown below, or a combination of several conditions including at least one of the conditions shown below.

[0340] (Conditions regarding the time of use of the wireless network) The first condition may also be a condition regarding the time of use of the wireless network (communication point). For example, the first condition may be that the present time is a predetermined time (for example, morning, noon, evening, or night). The time is not limited to morning, noon, evening, or night, but may also be a time specified by a specific time (for example, from 8 p.m. to 11 p.m.).

[0341] For example, a communication point may set a second period T2 so that transmission of SSB group G is continuously repeated during a first time period (e.g., peak hours). That is, the communication point may set the second period T2 to the same duration as the first period T1 multiplied by N during the first time period. Here, the communication point may also transmit the initial access signal in accordance with the conventional standard by setting the first period T1 to the same duration as the conventional standard. On the other hand, a communication point may set a second period T2 so that transmission of SSB group G is intermittently repeated during time periods other than the first time period. That is, the communication point may set the second period T2 to a duration longer than the first period T1 multiplied by N during time periods other than the first time period.

[0342] Furthermore, for example, the communication point may set the second period T2 so that transmission of SSB group G is intermittently repeated during a second time period (e.g., off-peak hours). That is, the communication point may set the second period T2 to a time longer than the first period T1 multiplied by N during the first time period. On the other hand, the communication point may set the second period T2 so that transmission of SSB group G is continuously repeated during time periods different from the second time period (e.g., peak hours). That is, the communication point may set the second period T2 to the same time as the first period T1 multiplied by N during time periods different from the second time period. Here, the communication point may transmit the initial access signal in accordance with the conventional standard by setting the first period T1 to the same period as the conventional standard.

[0343] (Conditions relating to the usage status of the wireless network) The first condition may also be a condition relating to the usage status of the wireless network (communication point). For example, the first condition may also be a condition relating to the connection status of the terminal device 30. For example, the first condition may be that no terminal device 30 connected to the communication point exists for a predetermined period of time (or that the number of terminal devices 30 connected to the communication point is less than a predetermined number), or that a terminal device 30 is accessing the communication point (or that the number of accesses by terminal devices 30 (UEs) to the communication point is greater than a predetermined number).

[0344] For example, the communication point may set the second period T2 so that the transmission of SSB group G is intermittently repeated when there are no terminal devices 30 connected to the communication point (or in the case of empty load). On the other hand, the communication point may set the second period T2 so that the transmission of SSB group G is continuously repeated when there are terminal devices 30 connected to the communication point. Here, the communication point may transmit the initial access signal in accordance with the conventional standard by setting the first period T1 to the same period as the conventional standard.

[0345] Furthermore, for example, the communication point may set a second period T2 so that the transmission of SSB group G is intermittently repeated when the number of terminal devices 30 connected to the communication point is less than a predetermined number (or in the case of low load). On the other hand, the communication point may set a second period T2 so that the transmission of SSB group G is continuously repeated when the number of terminal devices 30 connected to the communication point is more than a predetermined number. Here, the communication point may transmit the initial access signal in accordance with the conventional standard by setting the first period T1 to the same period as the conventional standard.

[0346] (Conditions relating to the use case of the wireless network) The first condition may also be a condition relating to the use case of the wireless network (communication point). For example, the first condition may be a condition indicating what use case the communication point will be used in by terminal equipment. More specifically, the use case may be, for example, a use case requiring power saving (e.g., NTN, RedCap, communication in mountainous areas, or communication in rural areas). Alternatively, the use case may be, for example, a use case requiring low latency (e.g., XR, video communication, or communication in urban areas). Note that the use cases are not limited to these examples. Multiple use cases may be combined and considered as a single use case.

[0347] (Other) The communication point may change the second period T2 to a longer period than the current period if the first condition is met.

[0348] For example, the communication point may start the timer when the connection of the last connected terminal device 30 ends. The communication point may continue the timer until the next connection request is received. The communication point may also change the second period T2 to a longer period than the current period as the time without a connection of terminal devices 30 increases. For example, the communication point may change the second period T2 to a longer period than the current period each time the timer value reaches a predetermined value (for example, each time a predetermined amount of time has elapsed). If a connection is made from terminal devices 30, the communication point may return the second period T2 to its original period (initial value). In this case, the original period (initial value) may be a period in which transmissions of SSB group G are continuously repeated, or a period in which transmissions of SSB group G are intermittently repeated.

[0349] Furthermore, for example, the communication point may start countering the number of transmissions of SSB group G after the connection of the last connected terminal device 30 has ended. The communication point may continue counting until the next connection request is received. The communication point may also lengthen the second period T2 as the counter number increases. For example, the communication point may change the second period T2 to a longer period than the current period each time the counter number reaches a predetermined value (for example, each time the counter number increases by a predetermined number). Of course, the communication point may also change the second period T2 to a longer period than the current period each time the counter number increases by 1. If a connection is made from terminal device 30, the communication point may return the second period T2 to its original period (initial value). In this case, the original period (initial value) may be a period in which transmissions of SSB group G are continuously repeated, or a period in which transmissions of SSB group G are intermittently repeated.

[0350] Furthermore, the communication point may change the second period T2 to a shorter period than the current period when the first condition is met. For example, the communication point may change the second period T2 to a shorter period than the current period each time the number of terminal devices 30 accessing the communication point reaches a predetermined number (one of several predetermined numbers).

[0351] The above describes the modification of the second period T2, but the communication point may modify the first period T1 in addition to or instead of the second period T2 if the first condition is met.

[0352] <4-3-3. Communication Point Status> The communication point may be in a sleep state or power-off state while SSB group G is not being transmitted (from the completion of transmission for SSB group G until the start of transmission for the next SSB group G).

[0353] <4-3-4. Composition of SSB Groups> The composition of SSB Group G does not necessarily have to be fixed.

[0354] For example, a communication point may flexibly change the number of repetitions of the initial access signal in one cycle T1 (i.e., the number of repetitions of the initial access signal in one SSB group G (N times)) depending on, for example, time and / or circumstances. For example, a communication point (e.g., the transmission control unit 231 of the base station 20) may change the number of repetitions of the initial access signal in one SSB group G (N times) when the second condition is met.

[0355] Here, the second condition may be the same as the first condition described above. For example, the second condition may be a condition relating to the time period during which the wireless network (communication point) is used, a condition relating to the usage status of the wireless network (communication point), or a condition relating to the wireless network (communication point) use case described above. Of course, the second condition may be different from the first condition described above.

[0356] <4-3-5. Functions of a Communication Point> In addition, a communication point may have the following functions:

[0357] For example, the communication point may have a mapping function / scheduling function for first broadcast information (e.g., PBCH) and / or first system information (e.g., SIB1) as shown in the signal configuration described later. The communication point may also have a function to generate a signal including the first broadcast information and / or first system information as shown in the signal configuration described later.

[0358] Furthermore, the mapping function and / or scheduling function may be changed for each communication point (for example, for each base station 20) depending on the use case. Here, the use case may be, for example, a use case that requires power saving (for example, NTN, RedCap, communication in mountainous areas, or communication in rural areas), or a use case that requires low latency (for example, XR, video communication, or communication in urban areas). Multiple use cases can be combined and considered as a single use case.

[0359] Furthermore, the communication point may have a function to change the ratio of the number of transmissions / allocations of the first broadcast information and the number of transmissions / allocations of the first system information within a single SSB group G. The communication point may also have a function to determine the types of the first broadcast information and / or the first system information to be included in a single SSB group G.

[0360] <4-3-6. Information included in the initial access signal> The communication point may also include at least one of the following (G1) to (G6) information in the initial access signal (first signal and / or first broadcast information).

[0361] (G1) First period T1 (G2) Second period T2 (G3) Information on the interval until the next transmission of SSB group G (G4) Information on the transmission schedule of SSB group G (G5) Information on the number of initial access signals included in one SSB group G (G6) Information on the transmission schedule of initial access signals in SSB group G

[0362] <4-3-7. Others> Communication points may be communication points that constitute a self-free network or a distributed antenna system. Multiple communication points may transmit the signals / information shown above (or signals / information as shown in the signal configuration below) by coordinated transmission.

[0363] Furthermore, multiple communication points may each transmit an initial access signal and / or SSB group G in different first cycles T1. Alternatively, multiple communication points may each transmit SSB group G in different second cycles T2.

[0364] Furthermore, the communication point may have a function to stagger the transmission timing of SSB group G in order to avoid interference caused by the overlapping transmission timing of SSB group G from multiple communication points.

[0365] For example, a communication point obtains information regarding the transmission start timing of SSB group G from another communication point that repeatedly transmits SSB group G in a second cycle T2. In this case, the communication point may obtain this transmission start timing information from another communication device. For example, the communication point may obtain the transmission start timing information from another communication point via backhaul or IAB. Of course, the communication point may also obtain the transmission start timing information from its own memory.

[0366] Furthermore, a communication point may start transmitting SSB group G at a different time than when other communication points start transmitting SSB group G. In this case, a communication point may shift the timing of its own SSB group G transmission start from the timing of other communication points' SSB group G transmission start by a length greater than the distance between itself and the other communication points.

[0367] <4-4. Signal Configuration of Initial Access Signal> Next, the signal configuration of the initial access signal in this embodiment will be described.

[0368] The initial access signals described below may be generated by means similar to the wireless transmission signal generation process in, for example, downlinks, uplinks, or sidelinks.

[0369] As described above, the initial access signal is, for example, a first signal and / or first broadcast information. Here, the first signal and / or first broadcast information is, for example, a signal / information having the same or similar function, purpose, and configuration as SSB in 5G. For example, the first signal is a signal having the same or similar function, purpose, and configuration as PSS and / or SSS, and the first broadcast information is information (or channel) having the same or similar function, purpose, and configuration as PBCH.

[0370] The initial access signal may include first system information. The first system information may be, for example, information with the same or similar functions, purposes, and configuration as SIB1. The first system information may also be, for example, information with the same or similar functions, purposes, and configuration as MIB. The first system information may be considered as part or all of the first broadcast information, or as information different from the first broadcast information.

[0371] The following describes the signal configuration of the first broadcast information and the first system information, which can be applied to the transmission of SSB group G (or periodic SSB transmission) as the initial access signal of this embodiment.

[0372] In the drawings used in the following description, an SSB is shown as an example of the first signal and / or first broadcast information. Figure 16 is a diagram showing an example of the signal configuration of an SSB. Figure 17 is a diagram showing another example of the signal configuration of an SSB. In the drawings used in the following description, the SSB may be illustrated as shown in Figure 17. However, the SSB shown in the drawings may be replaced with an SSB with a signal configuration like that shown in Figure 17. Of course, the signal configuration of the SSB is not limited to the signal configurations shown in Figures 15 and 16. Also, the first signal and / or first broadcast information is not limited to an SSB.

[0373] A communication point may have different first broadcast information (e.g., PBCH) included in each of the multiple initial access signals (e.g., multiple SSBs) included in a single SSB group G. For example, a communication point may set first broadcast information in at least one of the multiple initial access signals included in the SSB group G that is different from the first broadcast information (e.g., PBCH) included in the other initial access signals included in the SSB group G. For example, a communication point may set first broadcast information in at least one of the multiple initial access signals included in the SSB group G that has different content / resource amount / use case / transmission method than the first broadcast information (e.g., PBCH) included in the other initial access signals included in the SSB group G. In this case, each of the multiple first broadcast information included in a single SSB group G may have different information directed to different use cases and / or different types of terminal devices 30.

[0374] Furthermore, the communication point may have different first system information (e.g., SIB1) associated with each of the multiple initial access signals (e.g., multiple SSBs) included in the SSB group G. For example, the communication point may associate at least one of the multiple initial access signals included in the SSB group G with first system information that is different from the first system information associated with the other initial access signals included in the SSB group G. For example, the communication point may associate at least one of the multiple initial access signals included in the SSB group G with first broadcast information that has different content / resource amount / use case / transmission method than the first system information that the other initial access signals included in the SSB group G have. In this case, each of the multiple first system information included in one SSB group G may have different information directed to different use cases and / or different types of terminal devices 30. The first system information associated with an initial access signal can also be considered as part of the initial access signal. As described above, the first system information may be considered as part of or all of the first notification information, or as information different from the first notification information.

[0375] The following describes five examples of signal configurations.

[0376] <4-4-1. Signal Configuration Example 1> Figure 18 shows an example of the signal configuration of the initial access signal in this embodiment.

[0377] Multiple first broadcast information items included in one SSB group G may have a common signal configuration. The communication point may set information for notifying first system information (e.g., SIB1 and / or MIB) in the first broadcast information (e.g., PBCH). Here, the first system information indicated by at least one of the multiple first broadcast information items having a common signal configuration may differ in content or configuration from the first system information indicated by the other first broadcast information items among the multiple first broadcast information items. For example, the multiple first system information items indicated by the multiple first broadcast information items may differ for each use case and / or type of terminal device 30.

[0378] For example, a communication point may associate a use case with the first broadcast information. For example, a communication point may include information for notifying a use case in the first broadcast information. A use case may be a combination of multiple use cases. A communication point may prepare different notification information for each use case as information for notifying the first system information. Here, the notification information may include, for example, information for demodulating the first system information, which may be multiple sets of resource information corresponding to multiple use cases (e.g., CORESET0 and / or SearchSpace0). In addition, the notification information may be signal configuration information / resource information / scheduling information of the first system information (e.g., CORESET0, SearchSpace0, or PDCCH). Furthermore, a communication point may include one of the prepared multiple notification information (specifically, notification information corresponding to the use case associated with the first broadcast information) in each of the multiple first broadcast information.

[0379] Furthermore, for example, the communication point may associate the type of terminal device 30 with the first broadcast information. For example, the communication point may include information for notifying the type of terminal device 30 in the first broadcast information. The communication point may prepare different notification information for each type of terminal device 30 as information for notifying the first system information. Here, the notification information is, for example, the signal configuration information / resource information / scheduling information of the first system information (for example, CORESET0, SearchSpace0, or PDCCH). The communication point may also include one of the prepared notification information (specifically, the notification information corresponding to the type of terminal device 30 associated with the first broadcast information) for each of the multiple first broadcast information.

[0380] In this configuration example (Signal Configuration Example 1), the first system information may also be an on-demand signal. Transmitting a signal to wake up (or trigger) a communication point that supports on-demand operation can also be one of the use cases set in the first broadcast information.

[0381] <4-4-2. Signal Configuration Example 2> Figures 19 and 20 show other examples of the signal configuration of the initial access signal in this embodiment, respectively.

[0382] A communication point may set first system information in a field of first broadcast information (for example, a field of PBCH; hereinafter referred to as the broadcast information field). For example, a communication point may set some or all of the first system information in the broadcast information field of at least one of a plurality of initial access signals included in a single SSB group G. Here, the broadcast information field included in at least one of the plurality of initial access signals differs in content or configuration from the broadcast information fields of the other initial access signals among the plurality of initial access signals. Here, the first system information may include information corresponding to some or all of the use cases that the communication point can implement.

[0383] For example, a communication point may set the first system information in the broadcast information field of one of the multiple initial access signals included in a single SSB group G. In the example in Figure 19, the communication point sets the first system information in the broadcast information field of the first initial access signal among the multiple initial access signals included in a single SSB group G. The communication point may map the first system information (broadcast information field) with the first signal as a header, or it may map the first system information (broadcast information field) so that it is transmitted simultaneously with the first signal.

[0384] For example, a communication point may divide and store one first system information in each of the multiple broadcast information fields of the multiple initial access signals included in one SSB group G. In the example in Figure 20, the first system information, SIB1, is divided into three parts (SIB1_0 to SIB1_2). The communication point then stores one of the three divided first system information parts (SIB1_0 to SIB1_2) in each of the three broadcast information fields of the three initial access signals (the first signal and the first broadcast information 0 to 2) included in one SSB group G. The terminal device 30 may obtain the complete first system information by demodulating all the first broadcast information in the group. Note that the broadcast information fields in which the divided first system information (i.e., a part of the first system information) is stored do not necessarily have to be all the broadcast information fields included in one SSB group G. Within a single SSB group G, there may be broadcast information fields that do not contain the divided first system information (i.e., a portion of the first system information).

[0385] Note that the first system information shown in this configuration example (signal configuration example 2) may be a first system information with reduced information content. For example, the first system information notified by the above method may be a first system information that includes only the information necessary for transmitting the first uplink signal.

[0386] Furthermore, the first system information shown in this configuration example (signal configuration example 2) may be set in different notification information fields for each use case and / or type of terminal device 30.

[0387] <4-4-3. Signal Configuration Example 3> Figure 21 shows another example of the signal configuration of the initial access signal in this embodiment.

[0388] A communication point may change the usage of the fields of the first broadcast information (for example, the fields of the PBCH; hereinafter referred to as the broadcast information fields) within a single SSB group G. For example, a communication point may set first broadcast information with a different resource configuration than the first broadcast information held by other initial access signals included in the SSB group G to at least one of the multiple initial access signals included in the SSB group G. The resource configuration of the first broadcast information may be, for example, the occupied bandwidth and / or number of symbols of the broadcast information fields.

[0389] Figure 21 shows three first broadcast information streams (PBCH0-2) included in three single SSB groups G. PBCH1 has a larger occupied bandwidth compared to PBCH1 and PBCH2. PBCH2 has a larger occupied bandwidth compared to PBCH0 and has a larger number of symbols compared to PBCH0 and PBCH1.

[0390] The resource configuration for the first notification information may differ depending on the use case and / or the type of terminal device 30.

[0391] For example, a communication point may use a first broadcast information with a narrow bandwidth (e.g., a conventional PBCH) for use cases where bandwidth and / or transmission power are limited (e.g., RedCap or NTN) in a certain broadcast information field. In this case, the communication point may use the first broadcast information with a small bandwidth to notify resource information of the first system information, or to notify configuration information of the wake-up signal for the on-demand signal. The wake-up signal for the on-demand signal is a signal for waking up the communication point corresponding to the transmission of the on-demand signal.

[0392] Furthermore, for example, a communication point may use a first broadcast information with a wide bandwidth for use cases such as smartphones with less bandwidth limitation. In this case, the communication point may include a first system in the broadcast information field.

[0393] <4-4-4. Signal Configuration Example 4> Figure 22 shows another example of the signal configuration for the initial access signal in this embodiment.

[0394] A communication point may have multiple initial access signals in a single SSB group G with different communication standards for their signal configurations. For example, a communication point may have at least one of the multiple initial access signals in a single SSB group G have a signal configuration that is different from the signal configurations of the other initial access signals in the same SSB group G.

[0395] For example, a communication point may use at least one of the multiple initial access signals included in SSB group G as an initial access signal with a signal configuration defined in the conventional standard (hereinafter referred to as the conventional configuration). The communication point may also use other initial access signals included in the SSB group G as initial access signals with a signal configuration different from the conventional configuration (hereinafter referred to as the new configuration). As described above, the conventional standard may be a 5G (NR) communication standard or a communication standard of an earlier generation than 5G (for example, 4G (LTE)). The initial access signal of the new configuration may be any of the initial access signals of this embodiment (for example, the initial access signals of the signal configurations shown in signal configuration examples 1 to 5).

[0396] In the example shown in Figure 22, the communication point uses the first of several initial access signals included in one SSB group G (e.g., PSS, SSS, and PBCH) as the initial access signal in the conventional configuration, and the remaining initial access signals as the initial access signals in the new configuration.

[0397] Here, the initial access signal of the new configuration may include information not included in the initial access signal of the conventional configuration (hereinafter also referred to as new information). For example, the initial access signal of the new configuration may include information on the configuration of the wake-up signal so that the communication point corresponding to the transmission of an on-demand signal operates in standalone mode. If the amount of new information (for example, information on the configuration of the wake-up signal) is greater than a predetermined amount, the communication point may divide the new information into multiple first broadcast information items and store them.

[0398] <4-4-5. Signal Configuration Example 5> Figure 23 shows another example of the signal configuration of the initial access signal in this embodiment.

[0399] A communication point may store information about the first broadcast information held by other initial access signals included in an SSB group G in the first broadcast information held by one of the multiple initial access signals included in the SSB group G. For example, a communication point may designate one of the multiple first broadcast information held in an SSB group G as the master. The communication point then includes information about other first broadcast information within the SSB group G in the first broadcast information designated as the master.

[0400] In the example shown in Figure 23, the communication point designates the first broadcast information (e.g., PBCH) included in the first of several initial access signals included in one SSB group G as the master, and includes information about the remaining first broadcast information (PBCH1, PBCH2, ... shown in Figure 23) as list information in the first broadcast information designated as the master (master PBCH shown in Figure 23).

[0401] In the following explanation, information about other first broadcast information that is included in the first broadcast information designated as the master information is referred to as master information.

[0402] Here, the master information may be, for example, information indicating which use case and / or type of terminal device 30 the other first notification information is notifying first system information for.

[0403] Furthermore, for example, the master information may be information on a signal configuration of other first broadcast information. For example, the master information may be information indicating whether other first broadcast information includes information on a configuration of a wake-up signal, or may be information indicating whether other first broadcast information includes first system information.

[0404] Furthermore, for example, the master information may be information indicating whether the first system information notified by other first broadcast information is an on-demand signal. Further, for example, the master information may be information for notifying a transmission status of an on-demand signal (e.g., a list of transmission statuses of on-demand signals).

[0405] <4-5.Communication Processing> Next, several examples of communication processing according to the present embodiment will be described.

[0406] In the first example, as communication processing, transmission processing of an initial access signal in a power saving use case will be described. In the second example, as communication processing, transmission processing of an initial access signal in a low-latency use case will be described. In the third example, as communication processing, transmission processing of an initial access signal in a combined use case of a power saving use case and a low-latency use case will be described.

[0407] It should be noted that the examples shown below each provide an example of communication processing. The communication processing of the present embodiment is not limited to the processing shown in the following examples.

[0408] The communication processing of the present embodiment can be executed by, for example, a control unit of a communication point (e.g., a transmission control unit 231, a reception control unit 232, an acquisition unit 233, or a state control unit 234), and a control unit 33 of a terminal device 30 (e.g., a transmission control unit 331, a reception control unit 332, or an acquisition unit 333).

[0409] <4-5-1.First Example (Power Saving Use Case)> First, communication processing according to the first example will be described.

[0410] In the first embodiment, the transmission process of an initial access signal in a power-saving use case will be described as a communication process. A power-saving use case is a use case in which power saving is required or is possible. Specific examples of power-saving use cases include NTN, RedCap, Cell DTX (Discontinuous Transmission) / DRX (Discontinuous Reception), or IoT. Situations in which communication takes place in a power-saving use case include, for example, situations in which communication is expected to take place in an environment with a small number of connected terminals (or an environment with a low connection frequency). Specific examples of such situations include situations in mountainous and / or rural areas where communication takes place, situations in which communication takes place using cells placed to ensure area coverage, or situations in which communication takes place using cells intended for applications with a small absolute number or variety of corresponding terminal devices.

[0411] <Signal Configuration Example> Figure 24 shows an example of the signal configuration of the initial access signal according to the first embodiment. The signal configuration of the initial access signal can be as follows.

[0412] (SSB Group) The first period T1 may be a conventional SSB transmission period. The conventional SSB transmission period is the SSB transmission period defined in the conventional standard (5G or a communication standard of a generation prior to 5G). For example, the first period T1 may be 20 ms, 40 ms, 80 ms, or 160 ms.

[0413] Furthermore, the second period T2 may be a longer time. For example, the second period T2 may be the maximum value of the conventional SSB transmission period (160 ms), or it may be a longer period than the conventional SSB transmission period. For example, the second period T2 may be 160 ms, 320 ms, 500 ms, 540 ms, 1000 ms, 1080 ms, 1500 ms, 2000 ms, 5000 ms, 10000 ms, 15000 ms, 20000 ms, 50000 ms, or 100000 ms.

[0414] The number of SSBs (or SSB fusions) included in one SSB group G may be, for example, 4, 8, 16, 32, 64, or 128.

[0415] (First notification information) The first notification information may include configuration information of the wake-up signal for the on-demand signal.

[0416] Furthermore, the first broadcast information may include resource configuration information (for example, at least one of the occupied bandwidth and the number of symbols) of one or more first broadcast information included in one SSB group G.

[0417] Furthermore, the first notification information may include at least one of the following: the transmission time for the next SSB group, the interval until the next SSB group transmission, and the transmission cycle of the current SSB group (second cycle T2).

[0418] Furthermore, the first notification information may include information on the number of times the initial access signal has been repeatedly transmitted within the SSB group during the first period T1.

[0419] The communication point may include this information in one of the multiple first broadcast information items included in SSB group G. Alternatively, the communication point may include this information in each of the multiple first broadcast information items included in SSB group G. Alternatively, the communication point may divide and store this information among the multiple first broadcast information items included in SSB group G.

[0420] (First system information) The first system information may be notified by an on-demand signal (e.g., on-demand SIB1). In this case, the communication point does not need to transmit the first system information if, for example, no terminal devices 30 are connected.

[0421] A communication point may notify the terminal device 30 of the configuration information of a signal for waking up (or triggering) an on-demand signal by one or more first broadcast information included in the SSB group. Here, the communication point may notify the configuration information of a signal for waking up (or triggering) its own on-demand signal (on-demand SIB1), or it may notify the configuration information of a signal for waking up (or triggering) an on-demand signal (on-demand SIB1 and / or on-demand SSB) of another communication point.

[0422] Within the SSB group, resources may be provided for transmitting on-demand SIB1 for different use cases. The first broadcast information may include wake-up signal configuration information. The terminal device 30 may then decide which on-demand SIB1 to wake up based on the information included in the first broadcast information. The terminal device 30 may then generate a wake-up signal based on the wake-up signal configuration information and transmit it to the communication point.

[0423] <Sequence Example> Figure 25 is a sequence diagram showing the communication process according to the first embodiment. In this sequence example, the initial access signal is assumed to consist of a first signal and first broadcast information. In the example in Figure 25, the first signal is PSS / SSS. Also, in the example in Figure 25, the first broadcast information is PBCH. The communication process according to the first embodiment will be explained below with reference to the sequence diagram in Figure 25.

[0424] Communication points P １ The terminal device 30 starts the SSB transmission process (step S101). The terminal device 30 also starts a cell search (step S102).

[0425] Communication points P １This involves repeating the SSB group (multiple transmissions of the initial access signal in the first period T1) in the second period T2 (steps S103a to S105b). Here, the first broadcast information (PBCH) of the initial access signal may include configuration information of the wake-up signal. At this time, communication point P １ It is not necessary to send system information.

[0426] The terminal device 30 receives one or more initial access signals. The terminal device 30 obtains wake-up signal configuration information from the first broadcast information included in one or more initial access signals (step S106).

[0427] The terminal device 30 generates a wake-up signal based on the wake-up signal configuration information. Then, the terminal device 30 sends the generated wake-up signal to the communication point P １ Send to (step S107).

[0428] Communication point P receives the wake-up signal. １ The system then transitions to normal operation. For example, communication point P １ The system may then start transmitting system information (for example, first system information) (step S108).

[0429] The terminal device 30 that received the system information is at communication point P １ A first uplink signal (e.g., PRACH) is transmitted to it.

[0430] <4-5-2. Second Embodiment (Low Latency Use Case)> Next, the communication processing according to the second embodiment will be described.

[0431] In the second embodiment, the transmission process of an initial access signal in a low-latency use case is described as a communication process. A low-latency use case is a use case in which low latency is required. Specific examples of power-saving use cases include, for example, V2X (e.g., V2V, V2I, V2P, V2N), XR (e.g., VR, AR, or MR), or Mission-critical IoT. Situations in which communication takes place in a low-latency use case include, for example, situations in which location-based entertainment (LBE) is implemented using XR devices, situations in which dynamic / real-time data (e.g., sensing data or traffic data) is transmitted in V2X, or situations in which communication takes place in an industrial private network.

[0432] <Signal Configuration Example> Figure 26 shows an example of the signal configuration of the initial access signal according to the second embodiment. Figure 27 shows another example of the signal configuration of the initial access signal according to the second embodiment. The following configurations can be adopted for the signal configuration of the initial access signal.

[0433] (SSB group) The first period T1 may be the conventional SSB transmission period, or it may be a shorter period than the conventional SSB transmission period. For example, the first period T1 may be 5 ms, 10 ms, or 20 ms.

[0434] Furthermore, the second period T2 may be the first period T1 multiplied by the conventional SSB transmission period N, or it may be a longer period than the first period T1 multiplied by N, where N is the number of initial access signals transmitted in one SSB group G. For example, the second period T2 may be 5 ms, 10 ms, 15 ms, 20 ms, 25 ms, 30 ms, 35 ms, or 40 ms.

[0435] The number of SSBs (or SSB fusions) included in one SSB group G may be, for example, 1, 2, 4, 8, 16, 32, 64, or 128.

[0436] (First broadcast information) The communication point may arrange first system information corresponding to each use case in each broadcast information field within an SSB group, for example, as shown in FIG. 26.

[0437] The first broadcast information may include resource configuration information of one or more first broadcast information included in one SSB group G (for example, at least one of an occupied bandwidth and the number of symbols).

[0438] In addition, the first broadcast information may include at least one of a transmission time of a next SSB group, an interval until transmission of a next SSB group, and a transmission period of a current SSB group (second period T2). It should be noted that in low-latency use cases, compared with power-saving use cases, it is assumed that a terminal device 30 can obtain a desired SSB / SIB1 in a relatively short period. Therefore, these pieces of information do not necessarily have to be included in the first broadcast information.

[0439] In addition, the first broadcast information may include information on the number of repeated transmissions of an initial access signal in a first period T1 within an SSB group.

[0440] The communication point may include these pieces of information in one of a plurality of first broadcast information included in the SSB group G. In addition, the communication point may include these pieces of information in each of the plurality of first broadcast information included in the SSB group G. In addition, the communication point may divide these pieces of information into the plurality of first broadcast information included in the SSB group G and store them.

[0441] In addition, the communication point P １ may use one of a plurality of first broadcast information included in one SSB group G as a master, for example, as shown in FIG. 27. And the communication point P １The first broadcast information designated as the master may include information about other first broadcast information within a single SSB group G. Each of the multiple other first broadcast information may contain different information (e.g., information about different first system information) depending on the use case / situation (e.g., the use case / situation shown in the second embodiment). Here, the information about the first system information may be information for notifying the first system information, or it may be the first system information itself.

[0442] (First System Information) The communication point may transmit the first system information with different signal configurations / resources depending on the use case / situation (for example, the use case / situation shown in the second embodiment). The communication point may also make the content of the first system information different depending on the use case / situation (for example, the use case / situation shown in the second embodiment).

[0443] <Sequence Example> Figure 28 is a sequence diagram showing the communication process according to the second embodiment. In this sequence example, the initial access signal consists of a first signal and first broadcast information. In the example in Figure 28, the first signal is PSS / SSS. Also, in the example in Figure 28, the first broadcast information is PBCH. The communication process according to the second embodiment will be explained below with reference to the sequence diagram in Figure 28.

[0444] Communication points P １ The terminal device 30 starts the SSB transmission process (step S201). The terminal device 30 also starts cell search (step S202).

[0445] Communication points P １ This involves repeating the SSB group (multiple transmissions of the initial access signal in the first period T1) in the second period T2 (steps S203a to S205b). At this time, communication point P １ For example, as shown in Figure 26, multiple broadcast information fields within the SSB group may each contain different first system information depending on the use case / situation. Also, communication point P １For example, as shown in Figure 27, one of the multiple first broadcast information contained in one SSB group G may be designated as the master. The communication point may then include information about other first broadcast information within the SSB group G in the first broadcast information designated as the master.

[0446] The terminal device 30 receives multiple initial access signals. The terminal device 30 acquires one or more first system information contained in the multiple initial access signals (step S206). If multiple first system information has been acquired, the terminal device 30 may select a desired first system information from among the multiple first system information depending on the use case / situation.

[0447] The terminal device 30 that acquired the system information is at communication point P １ A first uplink signal (e.g., PRACH) is transmitted to (step S207).

[0448] <4-5-3. Third Embodiment (Composite Use Case)> Next, the communication processing related to the third embodiment will be described.

[0449] In the third embodiment, the transmission process of an initial access signal in a composite use case will be described as a communication process. The composite use case in the third embodiment is a use case in which power saving is required, as described in the first embodiment, and low latency is required, as described in the second embodiment, are mixed together.

[0450] <Signal Configuration Example> The following configuration can be used for the initial access signal.

[0451] (SSB Group) The first period T1 may be the conventional SSB transmission period, or it may be a shorter period than the conventional SSB transmission period. For example, the first period T1 may be 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, or 160 ms.

[0452] Furthermore, the second period T2 may be the transmission period of conventional SSB, a shorter period than the transmission period of conventional SSB, or a longer period than the transmission period of conventional SSB. For example, the second period T2 may be 5ms, 10ms, 15ms, 20ms, 25ms, 30ms, 35ms, 40ms, 80ms, 160ms, 320ms, 500ms, 540ms, 1000ms, 1080ms, 1500ms, 2000ms, 5000ms, 10000ms, 15000ms, 20000ms, 50000ms, or 100000ms.

[0453] The number of SSBs (or SSB fusions) included in one SSB group G may be, for example, 1, 2, 4, 8, 16, 32, 64, or 128.

[0454] Communication points P １ The transmission period of the SSB group (second period T2) may be dynamically changed. For example, communication point P １ The second period T2 may be changed, for example, depending on the number of connected terminals and / or the time.

[0455] For example, communication point P １ If there are no connected terminals or the number is less than a predetermined number, the second period T2 may be set to a long period (for example, 160 ms, 320 ms, 500 ms, 540 ms, 1000 ms, 1080 ms, 1500 ms, 2000 ms, 5000 ms, 10000 ms, 15000 ms, 20000 ms, 50000 ms, or 100000 ms).

[0456] For example, communication point P １ If there are no connected terminals or the number is less than a predetermined number, the second period T2 may be set to a short period (for example, 5 ms, 10 ms, 15 ms, 20 ms, 25 ms, 30 ms, 35 ms, 40 ms, 80 ms, or 160 ms).

[0457] For example, communication point P １During periods when terminal connection frequency is low (for example, at night, or during periods calculated statistically), the second period T2 may be set to a longer period (for example, 160 ms, 320 ms, 500 ms, 540 ms, 1000 ms, 1080 ms, 1500 ms, 2000 ms, 5000 ms, 10000 ms, 15000 ms, 20000 ms, 50000 ms, or 100000 ms).

[0458] For example, communication point P １ During periods of high terminal connection frequency (e.g., daytime, statistically calculated time periods, or core time), the second period T2 may be set to a shorter period (e.g., 5ms, 10ms, 15ms, 20ms, 25ms, 30ms, 35ms, 40ms, 80ms, or 160ms).

[0459] Also, communication points P １ The transmission cycle of the SSB group (second cycle T2) may be changed over time. For example, communication point P １ The timer / counter may be started when the connection to the last connected terminal device 30 ends. The communication point may continue the timer until the next connection request is received. Alternatively, the communication point may continue counting the number of times the initial access signal is transmitted until the next connection request is received. The communication point may also change the second period T2 to a longer period than the current period as the time without a connection to the terminal device 30 increases. For example, the communication point may change the second period T2 to a longer period than the current period each time the timer value / counter value reaches a predetermined value. The maximum period of the second period T2 (upper limit for lengthening the period) may be set in advance. １ If a terminal device 30 is connected, an initial access signal may be transmitted using the conventional SSB transmission cycle.

[0460] Furthermore, the relationship between the number of connected terminals and the first period T1 and / or the second period T2 may be pre-set. Communication point P １ The first period T1 and / or the second period T2 may be changed according to the number of connected terminals. In this case, the communication point P １The system can implicitly notify the terminal device 30 of its congestion status by changing the first period T1 and / or the second period T2 according to the number of connected terminals. That is, the terminal device 30 communicates the communication point P １ Even without explicit notification from, changes in the first period T1 and / or the second period T2 will cause communication point P １ You can find out how crowded it is.

[0461] (First broadcast information) The communication point may place first system information corresponding to each use case in each broadcast information field within the SSB group, for example, as shown in Figure 18, Figure 21, or Figure 22.

[0462] The first broadcast information may include resource configuration information (e.g., at least one of the occupied bandwidth and the number of symbols) of one or more first broadcast information included in one SSB group G.

[0463] Furthermore, the first notification information may include at least one of the following: the transmission time for the next SSB group, the interval until the next SSB group transmission, and the transmission cycle of the current SSB group (second cycle T2).

[0464] Furthermore, the first notification information may include information on the number of times the initial access signal has been repeatedly transmitted within the SSB group during the first period T1.

[0465] The communication point may include this information in one of the multiple first broadcast information items included in SSB group G. Alternatively, the communication point may include this information in each of the multiple first broadcast information items included in SSB group G. Alternatively, the communication point may divide and store this information among the multiple first broadcast information items included in SSB group G.

[0466] Also, communication points P １ For example, as shown in Figure 23 or Figure 27, one of the multiple first broadcast information included in one SSB group G may be used as the master. And the communication point P １The first broadcast information designated as the master may include information about other first broadcast information within a single SSB group G. Each of the multiple other first broadcast information may contain different information (e.g., information about different first system information) depending on the use case / situation (e.g., the use case / situation shown in the second embodiment). Here, the information about the first system information may be information for notifying the first system information, or it may be the first system information itself.

[0467] (First system information) Communication point P １ The first system information may be transmitted with different signal configurations / resources depending on the use case / situation (for example, the use case / situation shown in the second embodiment). Furthermore, the content of the first system information may differ at the communication point depending on the use case / situation (for example, the use case / situation shown in the second embodiment). Communication point P １ This may involve associating a first system information that is continuously and repeatedly transmitted (e.g., conventional SIB1) with an on-demand signal (e.g., on-demand SIB1) and including them simultaneously in a single SSB group.

[0468] <Sequence Example> Figure 29 is a sequence diagram showing the communication process according to the third embodiment. In this sequence example, the initial access signal is assumed to consist of a first signal and first broadcast information. In the example in Figure 29, the first signal is PSS / SSS. Also, in the example in Figure 29, the first broadcast information is PBCH. The communication process according to the third embodiment will be explained below with reference to the sequence diagram in Figure 29.

[0469] Communication points P １ The terminal device 30 starts the SSB transmission process (step S301). The terminal device 30 also starts a cell search (step S302).

[0470] Communication points P １ This involves repeating the SSB group (multiple transmissions of the initial access signal in the first period T1) in the second period T2 (step S303).

[0471] The terminal device 30 receives multiple initial access signals. The terminal device 30 acquires one or more first system information contained in the multiple initial access signals (step S304). If multiple first system information has been acquired, the terminal device 30 may select a desired first system information from among the multiple first system information depending on the use case / situation.

[0472] The terminal device 30 generates a first uplink signal / wake-up signal. The terminal device 30 then sends the generated signal to the communication point P １ Send to (step S305).

[0473] Communication point P that received the signal １ This changes the period of the second period T2 to a shorter period than the current period (step S306).

[0474] Once communication with terminal device 30 is complete, communication point P1 sends an RRC release message to terminal device 30 to terminate the connection with terminal device 30 (step S307).

[0475] If terminal device 30 that terminated the connection was the last terminal, then communication point P １ The timer / counter is started (step S308). If no connection is made from any of the terminal devices 30 for a predetermined time / number of times, the communication point P １ This changes the period of the second period T2 to a longer period than the current period (step S309).

[0476] And then, communication point P １ The timer / counter is restarted (step S310). If no connection is made from any of the terminal devices 30 for a predetermined time / number of times, communication point P １ This changes the period of the second period T2 to a longer period than the current period (step S311). Thereafter, communication point P １ This operation is repeated until the second period T2 reaches a predetermined upper limit.

[0477] Furthermore, if a connection is made from terminal device 30, communication point P１ The second period T2 may be reset to its initial value (for example, the period used in step S303).

[0478] <<5. Modifications>> The above-described embodiment is merely an example, and various modifications and applications are possible.

[0479] For example, the terminal device 30 of this embodiment may have a function to acquire information regarding the transmission of an initial access signal to a communication point. The information regarding the transmission of an initial access signal may be, for example, capability information of the communication point. The capability information of the communication point may be, for example, information indicating whether or not the communication point supports intermittent transmission of SSB group G. The information regarding the transmission of an initial access signal may also be information regarding the current transmission status of the initial access signal. The information regarding the current transmission status of the initial access signal may be, for example, information indicating whether the communication point is currently intermittently and repeatedly transmitting SSB group G, or continuously and repeatedly transmitting SSB group G. In addition, the information regarding the transmission of an initial access signal may be periodic information (for example, information on the first period and / or the second period), or configuration information of SSB group G.

[0480] Furthermore, in the above-described embodiment, one SSB group G includes multiple initial access signals. However, one SSB group G may contain only one initial access signal. In other words, one SSB group G may transmit an initial access signal only once.

[0481] Furthermore, in the above-described embodiment, multiple communication points within the cluster are configured to coordinately transmit information / signals to the UE (terminal device 30). In this case, the connection between the UE and the multiple communication points may be a connection using carrier aggregation technology, a connection using dual connectivity technology, or a connection using multi-connectivity technology.

[0482] Furthermore, in the above-described embodiment, the conventional standard is assumed to be a 5G or earlier generation communication standard. Here, the earlier generation communication standard is not limited to 4G, but may be, for example, 3G.

[0483] The functions of the base station 20 in this embodiment may be separated into multiple functions such as a CU (Central Unit), a DU (Distributed Unit), and a RU (Radio Unit). In this case, the above description of base station 20 (or BS) can be replaced with at least one of the CU, DU, and RU.

[0484] The control device that controls the management device 10, base station 20, or terminal device 30 in this embodiment may be implemented using a dedicated computer system or a general-purpose computer system.

[0485] For example, a program for performing the above-described operations is stored in a computer-readable recording medium such as an optical disc, semiconductor memory, magnetic tape, or flexible disk and distributed. Then, for example, the control device is configured by installing the program on a computer and executing the above-described process. In this case, the control device may be an external device (e.g., a personal computer) of the management device 10, base station 20, or terminal device 30. Alternatively, the control device may be an internal device (e.g., control unit 13, control unit 23, or control unit 33) of the management device 10, base station 20, or terminal device 30.

[0486] Alternatively, the above program may be stored on a disk drive provided by a server device on a network such as the Internet, and made available for download to a computer. Furthermore, the above functions may be realized through the cooperation of an OS (Operating System) and application software. In this case, the parts other than the OS may be stored on a medium and distributed, or the parts other than the OS may be stored on a server device and made available for download to a computer.

[0487] Furthermore, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically by known methods. In addition, the processing procedures, specific names, and information including various data and parameters shown in the above document and drawings can be arbitrarily changed unless otherwise specified. For example, the various information shown in each figure is not limited to the information shown.

[0488] Furthermore, the components of each illustrated device are functionally conceptual and do not necessarily need to be physically configured as shown. In other words, the specific forms of distribution and integration of each device are not limited to those shown, and all or part of them can be functionally or physically distributed and / or integrated in any unit according to various loads and usage conditions.

[0489] Furthermore, the embodiments described above can be combined as appropriate in areas where the processing content does not contradict each other. Also, the order of each step shown in the sequence diagram or flowchart of this embodiment can be changed as appropriate.

[0490] The functions realized by the components described herein may be implemented in a circuit or processing circuitry programmed to realize such functions. Here, the circuit or processing circuitry may be a general-purpose processor, an application-specific processor, an integrated circuit, an ASIC (Application Specific Integrated Circuit), a CPU (a Central Processing Unit), a conventional circuit, or a combination thereof. The processor includes transistors and other circuits. The processor may be considered as a circuit or processing circuitry. The processor may be a programmed processor that executes a program stored in memory.

[0491] In this specification, a circuit, unit, or means may be hardware programmed to perform the functions described herein, or hardware that performs the functions described herein. Such hardware may be any hardware disclosed herein. It may also be any hardware programmed to perform the functions described herein. It may also be any hardware known to perform the functions described herein. Here, suppose such hardware is a processor considered to be a type of circuit. In this case, the circuit, means, or unit may be a combination of hardware and software used to constitute the hardware and / or processor.

[0492] Furthermore, for example, this embodiment can be implemented as any configuration constituting a device or system. For instance, this embodiment can be implemented as a processor as a system LSI (Large Scale Integration), a module using multiple processors, a unit using multiple modules, or a set with additional functions added to a unit. In other words, this embodiment can also be implemented as a component of a device.

[0493] The system LSI may also be called a System on Chip (SOC). In other words, each of the devices described above or below (e.g., the management device 10, the base station 20, and the terminal device 30) may be interpreted as a processor (e.g., a CPU) as a system LSI (e.g., SoC), or a module that uses or constitutes such a processor. Furthermore, or alternatively, this embodiment may be implemented by any configuration that constitutes the device or system (e.g., a modem chip (baseband chip) or an RF (Radio Frequency) section, or a combination thereof). The RF section may include at least one of an RF circuit and an RF front-end. In other words, each of the devices described above or below may be interpreted as a modem chip (baseband chip) or an RF section, or a combination thereof. Furthermore, or alternatively, each of the devices described above or below may be interpreted as a module that uses or constitutes a modem chip or an RF section.

[0494] The modem chip performs signal processing for communications within the device (including the devices described above or below). The modem chip may have at least the function of a modulator or demodulator. The RF section may have at least one of the following functions: an RF transceiver (e.g., an RF upconverter and / or an RF downconverter), a power amplifier, and a low noise amplifier. The RF transceiver converts a baseband signal to an RF frequency. The power amplifier amplifies the signal for transmission from the antenna. The low noise amplifier amplifies the weak signal received from the antenna. Furthermore, or alternatively, the RF section (in particular, the RF front end) may include at least one of the above-mentioned power amplifier, low noise amplifier, envelope tracker, filter, duplexer, multiplexer, antenna switch, and antenna tuner.

[0495] The combination of a modem chip and an RF unit may be referred to as a modem-RF system. At least a portion of the modem chip or RF unit, or a combination thereof, may be included in a system LSI (e.g., SoC). For example, processing performed by at least a portion of the modem chip or RF unit, or a combination thereof (e.g., at least a portion of MAC layer processing / PHY layer processing) may be implemented by the system LSI. Here, MAC layer processing or PHY layer processing may be at least a portion of the processing performed by the devices in the above-described or later embodiments (e.g., management device 10, base station 20, and terminal device 30).

[0496] In this embodiment, a system refers to a collection of multiple components (devices, modules (parts), etc.), regardless of whether all components are located in the same enclosure. For example, multiple devices housed in separate enclosures and connected via a network, and a single device containing multiple modules in one enclosure, are both considered systems.

[0497] Furthermore, for example, this embodiment can adopt a cloud computing configuration in which a single function is shared and processed collaboratively by multiple devices via a network.

[0498] <<6. Conclusion>> According to this embodiment, the communication point (for example, the transmission control unit 231 of the base station 20) repeatedly transmits an SSB group G (multiple transmissions of the initial access signal in the first period T1) for the terminal device to make initial access to the wireless network in the second period T2. Then, the communication point (for example, the reception control unit 232 of the base station 20) receives an uplink signal (for example, PRACH) for initial access from the terminal device 30 that has received the initial access signal.

[0499] This allows the communication point to reduce or increase the transmission of the initial access signal depending on the situation, thereby achieving high communication performance. For example, by making the second period T2 a longer period, the transmission of the initial access signal can be reduced. Reducing the transmission of the initial access signal reduces power consumption and / or radio interference. Even if the transmission of the initial access signal is reduced, it is transmitted multiple times at short intervals (first period T1) within a single SSB group, so the synchronization accuracy of the terminal device 30 does not decrease significantly.

[0500] Furthermore, the communication point may be configured to set a second period T2 so that transmissions from SSB group G are performed intermittently and repeatedly.

[0501] This reduces the processing required to transmit the initial access signal, allowing the communication point to reduce power consumption. Furthermore, the reduced transmission of the initial access signal also reduces radio interference.

[0502] Furthermore, the communication point (for example, the state control unit 234 of the base station 20) may put the communication device into a sleep state or a power-off state while SSB group G is not being transmitted.

[0503] This allows for further reductions in power consumption.

[0504] Furthermore, the communication point may change at least one of the first period T1 and the second period T2 if the first condition is met.

[0505] This allows the communication point to transmit the optimal initial access signal according to the conditions.

[0506] Furthermore, the first condition may consist of one or more conditions, including at least one of the following: conditions relating to the time period during which the wireless network is used, conditions relating to the usage status of the wireless network, and conditions relating to the use cases of the wireless network.

[0507] This allows the communication point to transmit the optimal initial access signal according to the conditions.

[0508] Furthermore, when the first condition is not met, transmission of SSB group G may be performed intermittently and repeatedly. The communication point may change the second period T2 so that when the first condition is met, transmission of SSB group G is performed continuously and repeatedly.

[0509] This allows the communication point to transmit an optimal initial access signal according to the first condition. For example, in situations where there are many connected terminals, the communication point can maintain high synchronization accuracy of the terminal device 30 by repeatedly transmitting the initial access signal without interruption, as in the conventional method.

[0510] The first condition may be that no terminal devices access the communication device for a predetermined period of time, or that the number of terminal devices accessing the communication device is less than a predetermined number. The communication point may change the second period T2 to a longer period than the current period if the first condition is met.

[0511] This allows the communication point to transmit an optimal initial access signal according to the first condition. For example, when there are no connected terminals or only a few connected terminals, the communication point can reduce power consumption by extending the time during which the initial access signal is not transmitted.

[0512] The communication point may change the number of initial access signals included in one SSB group G (the number of times an initial access signal is repeatedly transmitted within an SSB group G) if the second condition is met.

[0513] This allows the communication point to transmit an optimal initial access signal according to the second condition. For example, when there are many connected terminals, the communication point can maintain high synchronization accuracy of the terminal device 30 by increasing the number of times the initial access signal is transmitted. When there are no connected terminals or only a few connected terminals, the communication point can reduce power consumption by decreasing the number of times the initial access signal is transmitted.

[0514] The communication point (acquisition unit 233 of the base station 20) may acquire information regarding the timing at which other communication points that repeatedly transmit SSB group G in a second cycle T2 begin transmitting SSB group G. The communication point (transmission control unit 231 of the base station 20) may then begin transmitting SSB group G at a timing different from that at which other communication points begin transmitting SSB group G.

[0515] This allows a communication point to minimize the overlap between its own SSB group G transmissions and those of other communication points. This reduces initial access signal reception errors caused by radio interference.

[0516] A communication point may set a first broadcast information in at least one of the multiple initial access signals included in multiple transmissions, the first broadcast information having a different content from the first broadcast information contained in the other initial access signals among the multiple initial access signals.

[0517] This allows the communication point to transmit a large amount of information to the terminal device 30.

[0518] A communication point may set information for notifying system information as the first broadcast information. Here, the first system information indicated by at least one of a plurality of initial access signals included in multiple transmissions may differ in content or structure from the first system information indicated by the other initial access signals among the plurality of initial access signals.

[0519] This allows the communication point to transmit a large amount of information to the terminal device 30.

[0520] The communication point may set first system information in the broadcast information field. Here, the broadcast information field included in at least one of the multiple initial access signals included in multiple transmissions may have different content or configuration from the broadcast information fields included in the other initial access signals among the multiple initial access signals.

[0521] This allows the communication point to transmit a large amount of information to the terminal device 30.

[0522] The communication point may store one piece of first system information in each of the fields of first broadcast information possessed by multiple initial access signals included in multiple transmissions.

[0523] This allows the communication point to transmit the first system information, which contains a large amount of data, to the terminal device 30.

[0524] A communication point may set a first broadcast information having a different resource configuration from the first broadcast information possessed by the other first access signals among the multiple initial access signals to at least one of the multiple initial access signals included in multiple transmissions.

[0525] This allows the communication point to transmit a large amount of information to the terminal device 30.

[0526] A communication point may use one of the multiple initial access signals included in multiple transmissions as a signal with a first signal configuration defined in a 5G or earlier generation communication standard. The communication point may also use other initial access signals with a signal configuration different from the first signal configuration.

[0527] This enables terminal devices 30 that only support conventional standards to receive the initial access signal.

[0528] A communication point may store information relating to the first broadcast information of other initial access signals among the multiple initial access signals in the first broadcast information of one of the multiple initial access signals included in multiple transmissions.

[0529] This makes it easier to process the initial access signal of the terminal device 30.

[0530] Although the embodiments of this disclosure have been described above, the technical scope of this disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the gist of this disclosure. Furthermore, components from different embodiments and modifications may be combined as appropriate.

[0531] Furthermore, the effects described in each embodiment of this specification are merely illustrative and not limiting, and other effects may also occur.

[0532] Furthermore, this technology can also be configured as follows: (1) A communication device comprising: a transmission control unit that repeatedly transmits an initial access signal, which includes a synchronization signal and broadcast information, multiple times in a first period for a terminal device to initially access a wireless network, in a second period longer than the first period; and a reception control unit that receives an uplink signal for the initial access. (2) The communication device according to (1), wherein the transmission control unit sets the second period so that the multiple transmissions of the initial access signal in the first period are repeated intermittently. (3) The communication device according to (2), further comprising: a state control unit that puts the state of the communication device into a sleep state or a power-off state when the multiple transmissions of the initial access signal in the first period are not being performed. (4) The communication device according to (2) or (3), wherein the transmission control unit changes at least one of the first period and the second period when the first condition is met. (5) The communication device according to (4), wherein the first condition is a condition comprising one or more conditions including at least one of the following: a condition relating to the time period of use of the wireless network, a condition relating to the usage status of the wireless network, and a condition relating to the use case of the wireless network. (6) The communication device according to (4) or (5), wherein when the first condition is not met, multiple transmissions of the initial access signal in the first cycle are repeatedly performed intermittently, and the transmission control unit changes the second cycle to continuously repeat the multiple transmissions of the initial access signal in the first cycle when the first condition is met. (7) The communication device according to (4) or (5), wherein the first condition is that there are no terminal devices accessing the communication device for a predetermined period of time, or that the number of terminal devices accessing the communication device is less than a predetermined number, and the transmission control unit changes the second cycle to a longer cycle than the current cycle when the first condition is met.(8) The communication device according to any one of (1) to (7), wherein the transmission control unit changes the number of initial access signals included in the multiple transmissions of the initial access signal in the first cycle when the second condition is met. (9) The communication device according to any one of (1) to (8), comprising an acquisition unit that acquires information regarding the timing at which other communication points that repeat the multiple transmissions of the initial access signal in the first cycle in a second cycle start the multiple transmissions of the initial access signal in the first cycle, wherein the transmission control unit starts the multiple transmissions of the initial access signal in the first cycle at a timing different from the timing at which the other communication points start the multiple transmissions of the initial access signal in the first cycle. (10) The communication device according to any one of (1) to (9), wherein the transmission control unit sets the broadcast information in at least one of the multiple initial access signals included in the multiple transmissions to have content different from the broadcast information in the other initial access signals among the multiple initial access signals. (11) The communication device according to any one of (1) to (9), wherein the transmission control unit sets information for notifying system information in the notification information, and the system information indicated by at least one of the multiple initial access signals included in the multiple transmissions is different in content or configuration from the system information indicated by the other initial access signals among the multiple initial access signals. (12) The communication device according to any one of (1) to (9), wherein the transmission control unit sets system information in the field of the notification information, and the field of the notification information included in at least one of the multiple initial access signals included in the multiple transmissions is different in content or configuration from the field of the notification information included in the other initial access signals among the multiple initial access signals. (13) The communication device according to any one of (1) to (9), wherein the transmission control unit divides and stores one piece of system information in each of the multiple notification information fields of the multiple initial access signals included in the multiple transmissions.(14) The communication device according to any one of (1) to (9), wherein the transmission control unit sets the notification information having a different resource configuration from the notification information having other initial access signals among the multiple initial access signals to at least one of the multiple initial access signals included in the multiple transmissions. (15) The communication device according to any one of (1) to (9), wherein the transmission control unit sets one of the multiple initial access signals included in the multiple transmissions to be a signal with a first signal configuration defined by a 5G or earlier generation communication standard, and sets the other initial access signals among the multiple initial access signals to be signal configuration signals different from the first signal configuration. (16) The communication device according to any one of (1) to (9), wherein the transmission control unit stores information relating to the notification information having other initial access signals among the multiple initial access signals in the notification information having one of the multiple initial access signals included in the multiple transmissions. (17) A communication device comprising: an acquisition unit that acquires information regarding the transmission of an initial access signal at a communication point that repeatedly transmits an initial access signal, including a synchronization signal and broadcast information, multiple times in a first cycle, in a second cycle longer than the first cycle, for a terminal device to initially access a wireless network; and a receiving control unit that receives the initial access signal from the communication point based on the information regarding the transmission of the initial access signal. (18) A communication method that repeatedly transmits an initial access signal, including a synchronization signal and broadcast information, multiple times in a first cycle, in a second cycle longer than the first cycle, for a terminal device to initially access a wireless network, and receives an uplink signal for the initial access. (19) A communication method that acquires information regarding the transmission of an initial access signal at a communication point that repeatedly transmits an initial access signal, including a synchronization signal and broadcast information, multiple times in a first cycle, in a second cycle longer than the first cycle, for a terminal device to initially access a wireless network, and receives the initial access signal from the communication point based on the information regarding the transmission of the initial access signal.(20) A communication system comprising a first communication device provided on a wireless network and a second communication device connectable to the wireless network, wherein the first communication device includes a transmission control unit that repeatedly transmits an initial access signal, including a synchronization signal and broadcast information, multiple times in a first period for the second communication device to initially access the wireless network, in a second period longer than the first period, and the second communication device includes a reception control unit that receives the initial access signal.

[0533] 1 Communication System 10 Management Device 20 Base Station 30 Terminal Device 11 Communication Unit 21, 31 Wireless Communication Unit 12, 22, 32 Storage Unit 13, 23, 33 Control Unit 211, 311 Transmission Processing Unit 212, 312 Reception Processing Unit 213, 313 Antenna 231, 331 Transmission Control Unit 232, 332 Reception Control Unit 233, 333 Acquisition Unit 234 Status Control Unit P Communication Point

Claims

1. A communication device comprising: a transmission control unit that repeatedly transmits an initial access signal, including a synchronization signal and broadcast information, multiple times in a first cycle, in a second cycle longer than the first cycle, for a terminal device to initially access a wireless network; and a reception control unit that receives the uplink signal for the initial access.

2. The communication device according to claim 1, wherein the transmission control unit sets the second period such that the multiple transmissions of the initial access signal in the first period are performed intermittently and repeatedly.

3. The communication device according to claim 2, further comprising a state control unit that puts the state of the communication device into a sleep state or a power-off state during the period when the multiple transmissions of the initial access signal in the first cycle are not performed.

4. The communication device according to claim 2, wherein the transmission control unit changes at least one of the first period and the second period when the first condition is met.

5. The communication device according to claim 4, wherein the first condition is a condition comprising one or more conditions including at least one of the following: a condition relating to the time period of use of the wireless network, a condition relating to the usage status of the wireless network, and a condition relating to the use case of the wireless network.

6. When the first condition is not met, multiple transmissions of the initial access signal in the first period are repeated intermittently, and when the first condition is met, the transmission control unit changes the second period so that multiple transmissions of the initial access signal in the first period are repeated continuously, the communication device according to claim 4.

7. The communication device according to claim 4, wherein the first condition is that no terminal devices access the communication device exist for a predetermined period of time, or that the number of terminal devices accessing the communication device is less than a predetermined number, and the transmission control unit changes the second period to a period longer than the current period when the first condition is met.

8. The communication device according to claim 1, wherein the transmission control unit changes the number of initial access signals included in multiple transmissions of the initial access signal in the first cycle when the second condition is met.

9. The communication device according to claim 1, comprising: an acquisition unit that acquires information regarding the timing at which another communication point that repeatedly transmits the initial access signal multiple times in the first cycle in the second cycle, starts transmitting the initial access signal multiple times in the first cycle, wherein the transmission control unit starts transmitting the initial access signal multiple times in the first cycle at a timing different from the timing at which the other communication point starts transmitting the initial access signal multiple times in the first cycle.

10. The communication device according to claim 1, wherein the transmission control unit sets the notification information in at least one of the plurality of initial access signals included in the plurality of transmissions to be different in content from the notification information contained in the other initial access signals among the plurality of initial access signals.

11. The communication device according to claim 1, wherein the transmission control unit sets information for notifying system information in the notification information, and the system information indicated by at least one of the multiple initial access signals included in the multiple transmissions differs in content or configuration from the system information indicated by the other initial access signals among the multiple initial access signals.

12. The communication device according to claim 1, wherein the transmission control unit sets system information in the field of the notification information, and the field of the notification information included in at least one of the multiple initial access signals included in the multiple transmissions has different content or configuration from the field of the notification information included in the other initial access signals among the multiple initial access signals.

13. The communication device according to claim 1, wherein the transmission control unit divides and stores one system piece of information in each of the fields of multiple notification information that have multiple initial access signals included in the multiple transmissions.

14. The communication device according to claim 1, wherein the transmission control unit sets the notification information having a different resource configuration from the notification information having other initial access signals among the multiple transmissions to at least one of the multiple initial access signals included in the multiple transmissions.

15. The communication device according to claim 1, wherein the transmission control unit sets one of the multiple initial access signals included in the multiple transmissions to a signal with a first signal configuration defined by a 5G or earlier generation communication standard, and sets the other initial access signals among the multiple initial access signals to signals with a signal configuration different from the first signal configuration.

16. The communication device according to claim 1, wherein the transmission control unit stores information relating to the notification information of other initial access signals among the multiple initial access signals in the notification information of one of the multiple initial access signals included in the multiple transmissions.

17. A communication device comprising: an acquisition unit that acquires information regarding the transmission of an initial access signal, which includes a synchronization signal and broadcast information, for a terminal device to initially access a wireless network, and which repeatedly transmits the initial access signal multiple times in a first cycle in a second cycle that is longer than the first cycle; and a receiving control unit that receives the initial access signal from the communication point based on the information regarding the transmission of the initial access signal.

18. A communication method comprising: transmitting multiple initial access signals, including a synchronization signal and broadcast information, in a first cycle for a terminal device to initially access a wireless network, repeatedly in a second cycle longer than the first cycle, and receiving an uplink signal for the initial access.

19. A communication method comprising: obtaining information regarding the transmission of an initial access signal, which includes a synchronization signal and broadcast information, for a terminal device to initially access a wireless network; the transmission of the initial access signal multiple times in a first cycle, and repeating this in a second cycle longer than the first cycle; and receiving the initial access signal from the communication point based on the information regarding the transmission of the initial access signal.

20. A communication system comprising a first communication device provided on a wireless network and a second communication device connectable to the wireless network, wherein the first communication device includes a transmission control unit that repeatedly transmits an initial access signal, including a synchronization signal and broadcast information, multiple times in a first cycle for the second communication device to initially access the wireless network, in a second cycle longer than the first cycle, and the second communication device includes a reception control unit that receives the initial access signal.

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