User equipment, base station and communication system

Abstract

To provide a user device capable of calculating a terminal position.SOLUTION: A terminal device 20, which is a user device, includes a communication unit that receives higher layer parameters related to a positioning reference signal (PRS) and a control unit that performs positioning using the positioning reference signal received based on the higher layer parameters. The higher layer parameters are hierarchical information including a resource set parameter having a plurality of resource parameters.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a base station for determining the position of a terminal device, a terminal device, a positioning method, and a wireless communication system. [Background technology]

[0002] In wireless communication systems, frequency selectivity and time fluctuations occur in the transmission path due to multipath fading, which occurs when a signal transmitted from a transmitter reflects off buildings and other objects, and Doppler fluctuations, which occur when a receiver moves. In a multipath environment where multipath fading occurs, the signal received by the receiver is a signal in which symbols arriving directly from the transmitter and symbols arriving later after being reflected off buildings and other objects interfere with each other.

[0003] In order to obtain better reception characteristics in a frequency-selective transmission path, wireless communication systems may use an Orthogonal Frequency Division Multiplexing (OFDM) transmission method, which is a Multiple Carrier (MC) block transmission method. In the Third Generation Partnership Project (3GPP), OFDM is used in the downlink, and OFDM and DFT-s-OFDM (Discrete Fourier Transform-Spread-OFDM) are used in the uplink.

[0004] NR (New Radio) was studied and standardized for fifth-generation mobile communication systems in 3GPP Release 15 (see Non-Patent Documents 1-3). NR aims to increase communication capacity by using multi-element antennas and performing beamforming toward users.

[0005] In LTE (Long Term Evolution), physical layer and upper layer technologies for positioning have been standardized. For example, the standard assumes Cell_ID (IDentification), ECID (Enhanced Cell ID), OTDOA (Observed Time Difference Of Arrival), and UTDOA (Uplink Time Difference Of Arrival). Non-Patent Document 4 discloses a positioning method using the OTDOA method in which a positioning reference signal (PRS) is transmitted from each of multiple base stations to a terminal device, and the terminal device estimates its position by calculating the difference in the reception time of the PRS.

[0006] In addition, the ECID method estimates the time required from transmission to reception on the uplink and downlink, as well as the angle of arrival, to determine the location of the terminal device. CRS (Cell Reference Signal) is used in the downlink, and SRS (Sounding Reference Signal) is used in the uplink. Furthermore, a base station equipped with a transmitter that transmits the PRS used in OTDOA positioning allocates the PRS in the time domain and frequency domain so as to avoid the CRS (Cell-specific Reference Signal) used only in LTE. CRS is a cell-specific reference signal defined in LTE that is used for measuring downlink reception quality, etc. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] 3GPP, “Physical layer procedures for data (Release 15)”, TS 38.214, v 15.2.0, 2018 / 6. [Non-patent document 2] 3GPP, “Physical channels and modulation (Release 15)”, TS 38.211, v 15.2.0, 2018 / 6. [Non-patent document 3] 3GPP, “Physical layer procedures for control (Release 15)”, TS 38.213, v 15.2.0, 2018 / 6. [Non-patent document 4] S. Fischer, “Observed Time Difference Of Arrival (OTDOA) positioning in 3GPP LTE”, Qualcomm White Paper Summary of the Invention [Problem to be solved by the invention]

[0008] However, since the Cell_ID, ECID, OTDOA method, and UTDOA method used in LTE are based on LTE, they may not be usable in systems other than LTE, such as the 5th generation mobile communication system, which is applicable to a wide range of frequency bands. For this reason, it is desirable to be able to calculate the terminal location even in systems other than LTE.

[0009] The present invention has been made in view of the above, and has an object to provide a user device capable of calculating a terminal position. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems and achieve the object, a user equipment according to the present invention includes a communication unit that receives higher layer parameters related to a positioning reference signal, and a control unit that performs positioning using the received positioning reference signal based on the higher layer parameters, wherein the higher layer parameters are hierarchical information including a resource set parameter having a plurality of resource parameters. In adjacent orthogonal frequency division multiplexing symbols, positioning reference signals are arranged at intervals of two or more resource elements. The positioning reference signals are arranged in active bandwidth portions. The control unit performs measurements of the positioning reference signals in measurement gaps. [Effects of the Invention]

[0011] The present invention has an effect of providing a user device capable of calculating the terminal position. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a configuration of a wireless communication system according to a first embodiment; [Figure 2] FIG. 1 is a diagram illustrating a functional block of a base station according to a first embodiment; [Figure 3] FIG. 1 is a diagram showing a control circuit according to a first embodiment; [Figure 4] FIG. 1 is a diagram illustrating an example of positioning by a base station according to a first embodiment; [Figure 5] 1 is a flowchart showing a positioning procedure according to the first embodiment; [Figure 6] FIG. 10 is a diagram illustrating another example of positioning by the base station according to the first embodiment. [Figure 7] 10 is another flowchart showing the procedure of positioning according to the first embodiment. [Figure 8] FIG. 1 is a diagram illustrating an example of positioning by a base station and a terminal device according to a first embodiment; [Figure 9] FIG. 1 is a diagram illustrating positioning using two TRPs according to a first embodiment. [Figure 10] FIG. 10 is a diagram showing positioning using an OTDOA method according to a second embodiment. [Figure 11] 10 is a flowchart showing a procedure for positioning in an OTDOA system according to a second embodiment. [Figure 12] FIG. 10 is a diagram illustrating a first example of an arrangement of PRSs according to a second embodiment. [Figure 13] FIG. 10 is a diagram illustrating a second example of an arrangement of PRSs according to the second embodiment. [Figure 14] FIG. 10 is a diagram illustrating a third example of an arrangement of PRSs according to the second embodiment. [Figure 15] FIG. 10 is a diagram illustrating a fourth example of an arrangement of PRSs according to the second embodiment. [Figure 16] FIG. 10 is a diagram illustrating a fifth example of an arrangement of PRSs according to the second embodiment. [Figure 17] FIG. 10 is a diagram illustrating a sixth example of an arrangement of PRSs according to the second embodiment. [Figure 18] FIG. 10 is a diagram illustrating a seventh example of an arrangement of PRSs according to the second embodiment. [Figure 19] FIG. 10 is a diagram illustrating an eighth example of an arrangement of PRSs according to the second embodiment. [Figure 20] FIG. 13 is a ninth example of an arrangement of PRSs according to the second embodiment. [Figure 21] FIG. 19 illustrates a tenth example of an arrangement of PRSs according to the second embodiment. [Figure 22] FIG. 11 illustrates an eleventh example of an arrangement of PRSs according to the second embodiment. [Figure 23] FIG. 12 is a diagram illustrating a twelfth example of an arrangement of PRSs according to the second embodiment. [Figure 24] FIG. 13 is a diagram illustrating a thirteenth example of an arrangement of PRSs according to the second embodiment. [Figure 25] FIG. 10 is a diagram showing an example of muting according to the second embodiment. [Figure 26] FIG. 10 is a diagram showing another example of muting according to the second embodiment. [Figure 27] FIG. 13 shows positioning by switching between LTE and NR according to a fifth embodiment. [Figure 28] FIG. 20 is a diagram showing an example of an arrangement of positioning reference signals according to a sixth embodiment; [Figure 29] FIG. 29 is a diagram showing a waveform of a signal in one OFDM symbol in which the positioning reference signal shown in FIG. 28 is arranged. [Figure 30] FIG. 10 is a diagram showing an example in which a positioning reference signal is arranged in multiple symbols. [Figure 31] FIG. 20 is a diagram showing an example of switching beams for each section in which the same waveform occurs within one OFDM symbol according to the sixth embodiment. [Figure 32] FIG. 13 is a diagram showing an example of how a panel number, a resource set, and a resource are linked when multiple panels are used according to the seventh embodiment. [Figure 33] FIG. 20 is a diagram illustrating an example in which a UE according to a seventh embodiment transmits an SRS to different base stations. [Figure 34]FIG. 20 is a diagram showing an example of SRS multiplexed in the time domain according to the eighth embodiment; [Figure 35] FIG. 20 is a diagram showing an example of arrangement of SRSs multiplexed in the frequency domain according to the eighth embodiment; [Figure 36] FIG. 20 is a diagram illustrating an example of transmitting SRS resource information from a terminal device to a base station according to an eighth embodiment. [Figure 37] FIG. 20 is a diagram illustrating an example of transmitting SRS resource information from a terminal device according to an eighth embodiment to a plurality of base stations. DETAILED DESCRIPTION OF THE INVENTION

[0013] A base station, a terminal device, a positioning method, and a wireless communication system according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

[0014] Embodiment 1 FIG. 1 is a diagram illustrating a configuration of a wireless communication system according to a first embodiment. The wireless communication system includes a base station 10 and a plurality of terminal devices 20. In the ECID method in LTE, distance is measured based on the time it takes for a signal transmitted between the base station 10 and the terminal device 20 to be received by the receiving side. The base station 10 estimates the angle of arrival (AoA) of the signal received from the terminal device 20. The base station 10 also performs positioning of the terminal device 20 based on the angle and distance information. In downlink communication, the base station 10 is the transmitting device, and the terminal device 20 is the receiving device. Since a terminal device is generally called a UE (User Equipment), the terminal device 20 is also called a UE in this embodiment. Although the positioning method in this embodiment is called the ECID method, this does not mean that it is the same as the ECID method in LTE, and a different name may be used. In the 3GPP standard, the base station is also called a gNodeB.

[0015] 2 is a diagram illustrating functional blocks of the base station 10 according to the first embodiment. The base station 10 includes a control unit 101, a transmission signal generation unit 102, a transmission processing unit 103, a reception processing unit 104, a reception signal decoding unit 105, and a positioning processing unit 106. The control unit 101 receives an instruction from the server 200 and transmits a control signal to the transmission signal generation unit 102. The control signal transmitted by the control unit 101 may be in the form of RRC (Radio Resource Control), MAC-CE (Medium Access Control-Control Element), or DCI (Downlink Control Information). The transmission signal generation unit 102 generates a signal to be transmitted to the terminal device 20 based on the control signal. The transmission processing unit 103 performs transmission processing on the signal generated by the transmission signal generation unit 102 and generates a transmission signal. The transmission processing unit 103 transmits a beam to the terminal device 20. The transmission processing unit 103 also transmits a synchronization signal, which is a signal for synchronizing with the terminal device 20, is used for communication with the terminal device 20, and stores resource information indicating resources associated one-to-one with the beams. The synchronization signal includes an SSB (Synchronization Signal Block). The SSB is a signal used for initial connection and synchronization in 3GPP Release.15.

[0016] The reception processing unit 104 performs reception processing on the received signal. The received signal decoding unit 105 decodes the received signal that has been subjected to reception processing, and transmits the decoded information to the server 200. The positioning processing unit 106 determines the location of the terminal device 20 using resources selected by the terminal device 20. The resource information targets SSB and is distributed in the time domain and the frequency domain. The positioning processing unit 106 also identifies the beam selected by the terminal device 20 using the resource information included in the synchronization signal to which the terminal device 20 responded, and calculates the location of the terminal device 20 using the beam. The operation of the positioning processing unit 106 will be described in detail later. The information transmitted from the received signal decoding unit 105 is a report, frequency information, or reference signal transmitted from the terminal device 20. A Location Management Function (LMF) functioning in the server 20 issues an instruction to the base station 10 to start or end positioning using NRPPa (New Radio Positioning Protocol A). Note that the terminal device 20 may determine the location of the terminal device 20 by positioning itself. For example, the terminal device 20 may determine the location of the terminal device 20 by performing positioning when making a call. This call may be, for example, when making an emergency call. Furthermore, the location information of the terminal device 20 obtained by positioning may be notified to the called party by the above-mentioned call. This notification may be made, for example, when the call is an emergency call. This allows, for example, the called party to quickly obtain location information of the terminal device that made the call. When the terminal device 20 performs positioning, the terminal device 20 may or may not notify the base station 10 of the start of positioning. The base station 10 may notify the LMF of the start of positioning of the terminal device 20. This notification from the base station 10 to the LMF may be made using the notification made from the terminal device 20 to the base station 10, or may not be made using the notification made by the terminal device 20 to the base station 10.

[0017] The control unit 101, transmission signal generation unit 102, transmission processing unit 103, reception processing unit 104, reception signal decoding unit 105, and positioning processing unit 106 are realized by processing circuits, which are electronic circuits that perform each process.

[0018] This processing circuit may be dedicated hardware, or a control circuit including a memory and a CPU (Central Processing Unit) that executes a program stored in the memory. Here, the memory may be, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), or a flash memory, a magnetic disk, or an optical disk. FIG. 3 is a diagram showing a control circuit according to the first embodiment. When this processing circuit is a control circuit including a CPU, this control circuit is, for example, a control circuit 400 having the configuration shown in FIG. 3.

[0019] As shown in Fig. 3, the control circuit 400 includes a processor 400a, which is a CPU, and a memory 400b. When implemented by the control circuit 400 shown in Fig. 3, the processor 400a reads and executes programs corresponding to each process stored in the memory 400b. The memory 400b is also used as a temporary memory for each process performed by the processor 400a.

[0020] When estimating the reception angle, the base station 10 can extract angle information using the transmission and reception beams. The transmission and reception beams are configured in two dimensions, but may be configured in three dimensions. The base station 10 can also extract three-dimensional angle information. When the base station 10 extracts angle information using the transmission and reception beams, the base station 10 receives information on appropriate beam information from the terminal device 20 during positioning, and converts it into AoA information based on the beam information.

[0021] FIG. 4 is a diagram illustrating an example of positioning by the base station 10 according to the first embodiment. In FIG. 4(a), the base station 10 uses a beam to find the terminal device 20. In FIG. 4(b), after finding the terminal device 20, the base station 10 measures the distance and angle between the base station 10 and the terminal device 20. As shown in FIG. 4(a), when performing initial connection, the base station 10 uses a beam to sweep a wide range to find the terminal device 20. Therefore, the accuracy of the obtained angle information is lower than when sweeping a narrow range. However, if the base station 10 wants to quickly obtain angle information of the terminal device 20, the base station 10 may perform positioning of the terminal device 20 using the angle information obtained at the time of initial connection. Note that, in addition to received power, BLER (Block Error Rate) prediction information or the like may be used as a beam selection criterion. Note that the terminal device 20 may report to the base station 10 the SSB identification number corresponding to the beam with the strongest received power from among the identification numbers of multiple SSBs transmitted from the base station 10 during initial synchronization. Since the base station 10 transmits one SSB for one beam, there is a one-to-one correspondence between the beam and the SSB. In other words, if the base station 10 can grasp the SSB identification number, it can grasp which beam has been selected by the terminal device 20.

[0022] There are various methods for identifying SSBs and beams, and the terminal device 20 can report identification information to the base station 10 using various SSB methods. For example, the terminal device 20 and the base station 10 can report by transmitting frequency information or a reference signal in the time domain and the frequency domain. A collection of REs (Resource Elements) distributed in the time domain and the frequency domain is called a resource. For example, in LTE, as described in Non-Patent Document 2, a resource block consists of 12 subcarriers in the frequency domain. In this embodiment, the subcarriers are replaced with REs for explanation. The base station 10 stores and transmits information indicating resources in an SSB. The terminal device 20 responds to the base station 10 using resources specified in the SSB, allowing the base station 10 to determine which SSB the terminal device 20 responded with. Furthermore, by determining which SSB the response is for, the base station 10 can determine which beam the terminal device 20 selected. If the terminal device 20 selects only one beam, the terminal device 20 responds using one time and one frequency resource. Specifically, an example of an SSB identification number is the SS Block Resource Indicator (SSBRI). The SSBRI is an index that specifies the predetermined arrangement of symbols and REs to be used to transmit SSBs in frequency and time. In other words, if the SSBRI changes, the beam used to transmit the SSB corresponding to the SSBRI also changes. Note that beam-based positioning is effective when used in the FR2 frequency band, which ranges from around 24 GHz to around 52 GHz, and is capable of forming relatively narrow beams compared to lower frequencies. Beam-based positioning allows accurate and quick acquisition of angle information, enabling low-latency positioning.

[0023] The server 200 may associate the beam with the resources used by the terminal device 20 to respond. In 3GPP, the response from the terminal device 20 to the base station 10 is called Mg.1. The access permission from the base station 10 in response to Mg.1 is called Mg.2. The information transmitted in Mg.1 is called a PRACH (Physical Random Access Channel). Mg.3 and Mg.4 may be provided, and the terminal device 20 may issue an RRC connection request in Mg.3, and the base station 10 may transmit RRC connection setting information in Mg.4. The beam for the uplink of Mg.3 may be the beam used to send Mg.1, or a different beam. The waveform and resources of the transmission signal used to send Mg.3 are specified by the base station 10 for the terminal device 20. That is, the base station 10 may perform positioning after processing Mg.1.

[0024] 5 is a flowchart showing a procedure for positioning according to the first embodiment. The base station 10 makes an initial connection with the terminal device 20 (step S1). The base station 10 receives beam information and information necessary for distance measurement (step S2). The base station 10 performs positioning of the terminal device 20 using the beam information and information necessary for distance measurement (step S3). In this embodiment, the position of the base station 10 is known, and if the beam selected by the terminal device 20 can be determined, the base station 10 can determine the direction in which the terminal device 20 is located. The base station 10 may measure the distance by measuring the time required for a round trip using a method such as a TA (Timing Advance) method for distance estimation, or by using PRACH.

[0025] 6A and 6B are diagrams showing another example of positioning by the base station 10 according to the first embodiment. In FIG. 6A, a coarse search is performed. In FIG. 6B, a fine search is performed. In FIG. 6C, positioning is performed after the fine search. The base station 10 may perform positioning after the fine search as shown in FIG. 6B.

[0026] FIG. 7 is another flowchart showing a positioning procedure according to the first embodiment. The base station 10 establishes an initial connection with the terminal device 20 and synchronizes with it (step S11). After the initial connection is completed, the base station 10 enters an RRC_CONNECTED state, i.e., a state after connection (step S12). The base station 10 performs beam management using SSB or a reference signal, a CSI-RS (Channel State Information-Reference Signal), and performs beam search toward the terminal device 20 by narrowing the beam spacing compared to that during the initial connection to increase resolution (step S13). After the initial connection or beam management process is completed, the base station 10 transmits CSI-RS or SSB to the terminal device 20 via downlink. The base station 10 also receives beam information and information required for distance measurement, which are fed back from the terminal device 20 (step S14). The base station 10 also uses this information to select a beam ID and uses the fed-back information as angle information. The terminal device 20 transmits an SRS (Sounding Reference Signal) to the base station 10. The base station 10 measures the distance by measuring the time required for the round trip between the SBB and the SRS, and performs positioning (step S15). Note that if the positioning time of the base station 10 is limited, positioning may be performed by a rough search in beam selection.

[0027] When the base station 10 performs a beam search using CSI-RS, the terminal device 20 may report the port number used for the CSI-RS with the strongest power among the received CSI-RS. In this embodiment, NZP-CSI-RS (Non-Zero Powered-CSI-RS) defined in Non-Patent Document 2 and the like is used as an example. The port number is a number for identifying the service used for communication by the base station 10 and the terminal device 20. The port number is linked to the frequency and time position where the CSI-RS is allocated, and to the type of code if code multiplexed. If the port number can be determined, the terminal device 20 can determine the position of the CSI-RS and the code applied to the CSI-RS. Note that here, the CSI-RS port and the transmission beam are linked in a one-to-one relationship, so the base station 10 can determine which beam has been selected from the reported port number. Furthermore, the terminal device 20 may report a CSI-RS Reference Indicator (CRI) to the base station 10 instead of the CSI-RS port. In other words, a change in the CRI changes the beam that transmits the CSI-RS corresponding to the CRI. By knowing the reported CRI, the base station 10 can ascertain which beam transmitted from the base station 10 has been selected by the terminal device 20.

[0028] FIG. 8 is a diagram illustrating an example of positioning by the base station 10 and the terminal device 20 according to the first embodiment. In FIG. 8(a), the base station 10 performs a coarse search. In FIG. 8(b), the base station 10 performs a fine search. The terminal device 20 also performs a search. In FIG. 8(c), the base station 10 calculates the angle and distance of the terminal device 20 using the beam of the terminal device 20. As shown in FIG. 8(c), the angle information may be a beam number on the base station 10 side or a beam pair link (BPL) combining the beam number on the base station 10 side and the beam number on the terminal device 20 side. The BPL is used to store which beam combination was optimal. If communication is interrupted and communication is to be resumed, the stored BPL can be used to establish a transmitter-receiver pair without performing beam sweeps again on the transmitter and receiver sides. Furthermore, highly accurate positioning can be achieved by having the base station 10 and the terminal device 20 perform positioning using beams that are optimal for each other. In the above example, the terminal device 20 uses the criterion of selecting a beam with strong received power, but it may also use a characteristic evaluation value such as BLER obtained from the received signal.

[0029] The base station 10 can perform beam management using the SRS transmitted in the uplink. In this case, the base station 10 observes the SRS transmitted from the terminal device 20 and selects an appropriate uplink beam. Then, the base station 10 creates a BPL using information from the CSI-RS and SRS. Obtaining information from the SRS and CSI-RS allows for more accurate angle information to be obtained. Furthermore, when digital precoding is performed, the terminal device 20 selects an appropriate codebook number. The codebook is specified by 3GPP TS38.214 as described in Non-Patent Document 1. The processing of the higher layer protocol extracts angle information using the SSB identification number, CSI-RS port number, beam ID number, or codebook number reported by the terminal device 20. In the CSI-RS, the CRI may be used as the beam ID number, and in the SRS, the SRS Resource Indicator (SRI) may be used as the beam ID number. Like the CRI, the SRI also links the beam to the frequency and time location where the SRS is placed.

[0030] In NR, RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), RSSI (Reference Signal Strength Indicator), or RI (Rank Indicator) is used as information to be reported, and the base station 10 may use these to estimate distance. In this case, RSRP, RSRQ, or RSSI is transmitted from the base station 10 to the LMF. For example, by using RSRP, the amount of attenuation of received power can be known, which can be used to measure distance. RSRQ or RI is used when determining whether a signal received by the terminal device 20 is suitable for positioning. For example, a high RI value indicates a large amount of reflected waves, and it can be determined that the signal is not suitable for positioning.

[0031] In this embodiment, the distance between the base station 10 and the terminal device 20 is measured based on the transmission times required for uplink and downlink. Signals used for distance measurement in the downlink may include SSB, CSI-RS, etc., but PRACH, SRS, or DMRS (DeModulation Reference Signal) may also be used in the uplink. For SRS, the processing flow is specified in RRC. Furthermore, in this embodiment, the RRC parameter "usage" of the SRS may explicitly indicate that the SRS is used for positioning, such as "positioning." By the base station 10 informing the terminal device 20 that the SRS is for positioning, the terminal device 20 can perform appropriate processing, such as prioritizing positioning processing. Furthermore, a parameter name that indicates that the SRS is for positioning, such as CSI-RS-Resource-Positioning, may be prepared.

[0032] It is also possible to perform positioning using multiple TRPs (Transmission Reception Points) or panels. A panel is an antenna equipped with multiple antenna elements, and it is possible for a base station to perform communication using multiple panels. The panels may be physically separated. Furthermore, if there is an obstacle in front of the panels, it is also possible to turn off the power of some panels and not use them. In this case, positioning may be performed using an average value obtained by using multiple estimated values ​​of the arrival angle and distance. Positioning may also be performed using candidate values ​​excluding the maximum or minimum value. FIG. 9 is a diagram illustrating positioning using two TRPs according to the first embodiment. In FIG. 9, the base station 10 performs positioning using two TRPs. In this case, two sets of angle information and distance information are obtained, and the base station 10 performs positioning using the two sets of information. Furthermore, as in the example shown in FIG. 9, when positioning is performed using multiple TRPs, PRACHs are sent for the number of received beams. In this case, the obtained angle information and distance information can be combined for each panel or TRP, so an identification number, such as an ID number for the TRP, may be created for each combination and reported to the positioning processing unit 106.

[0033] The node (NG_RAN_NODE) ​​connected to the 5G core network transmits information necessary for positioning calculation to the LMF. Examples of information necessary for positioning calculation include the carrier frequency, the band used, the number of antenna ports used, the beam information or beam pair number of the base station 10 or the terminal device 20, and the selected codebook information. This information may also include values ​​indicating the SFN (Slot Frame Number), the antenna and panel positions, and the subcarrier spacing used. In NR, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, or 480 kHz are available. Furthermore, information such as RSRQ or RSRP may also be transmitted. Furthermore, when OFDM or DFT-s-OFDM is used in the uplink, information regarding the applied CP length and BWP (BandWidth Parts) may be transmitted from the NG_RAN_NODE to the LMF.

[0034] As described above, in this embodiment, the base station 10 transmits a synchronization signal or a reference signal that stores resource information indicating resources associated with beams on a one-to-one basis, and calculates the position of the terminal device 20 using the resource information. Therefore, even when multipath occurs, the base station 10 can identify the beam selected by the terminal device 20 by referring to the resource information included in one of the multiple signals generated by the multipath, and can calculate the position using the beam selected by the terminal device 20. Therefore, using a beam increases directivity, and by reducing the number of reflected waves even in a multipath environment, the receiving side can receive only the main signal without being affected by reflections. In an environment where reflected waves exist, multiple angles of arrival exist, so using a transmission method that can receive only the main signal improves the accuracy of selecting the optimal beam on the receiving side. Furthermore, when calculating the round-trip time in distance measurement, receiving reflected waves degrades the calculation accuracy of the round-trip time of the main signal. This makes it possible to suppress degradation in the accuracy of calculating the position of the terminal device 20, even in a multipath environment.

[0035] Embodiment 2 FIG. 10 is a diagram illustrating positioning using the OTDOA method according to the second embodiment. As shown in FIG. 10, multiple base stations 10 transmit positioning reference signals to a terminal device 20 for positioning. In this embodiment, as an example, it is assumed that the TRPs in FIG. 10 are the base stations 10, and that each TRP is assigned a unique cell ID (Identification). Note that when implementing this method, it is assumed that synchronization is achieved between the base stations 10. The terminal device 20 receives reference signals and performs positioning using the difference in reception time of each reference signal. Details of positioning using the OTDOA method are described in Non-Patent Document 4. In FIG. 10, t1 indicates the difference between the reception time of a slot containing a PRS transmitted from TRP1 and the reception time of a slot containing a PRS transmitted from TRP2, and t2 indicates the difference between the reception time of a slot containing a PRS transmitted from TRP2 and the reception time of a slot containing a PRS transmitted from TRP3. t3 indicates the difference between the reception time of a PRS transmitted from TRP3 and the reception time of a PRS transmitted from TRP4. t4 indicates the difference between the reception time of the PRS transmitted from TRP4 and the reception time of the PRS transmitted from TRP1. In downlink communication, a slot is a unit consisting of 14 OFDM symbols, and in uplink communication, a slot is made up of 14 OFDM symbols or DFT-s-OFDM symbols. Although a slot containing a PRS is used as an example, the PRS may be included in a unit of shorter length than a slot, for example, a non-slot consisting of 2, 4, or 7 symbols, and the time difference when the non-slot is received may also be used. The reception time difference is called RSTD (Reference Signal Time Difference). The PRS may also be called NR PRS.

[0036] The positioning reference signal may be transmitted after beam sweeping is completed and the beam for the terminal device 20 is determined. That is, the PRS is transmitted in the above-mentioned Msg. 4 or after transmitting Msg. 4. This is because, when the positioning signal is transmitted after beam sweeping is completed, the position of the terminal device 20 can be determined and the power for transmitting the positioning reference signal can also be concentrated toward the terminal device 20.

[0037] 11 is a flowchart showing a procedure of positioning in the OTD-OA method according to the second embodiment. Steps S21 to S23 are the same processes as steps S11 to S13. The base station 10 transmits a PRS to the terminal device 20 (step S24). Step S25 is the same process as step S15. Note that in the OTD-OA method, synchronization may be established between the base station 10 and the terminal device 20, and a positioning reference signal may be transmitted in the RRC_CONNECTED state specified by 3GPP.

[0038] Positioning reference signals need to be orthogonal in the frequency domain and the time domain. In LTE, positioning reference signals are allocated so as not to overlap with CRSs. However, CRSs are not allocated in NR, a standard for 5G, which enables more efficient allocation that differs from LTE. FIG. 12 is a diagram illustrating a first example of PRS allocation according to a second embodiment. The diagram of the RRS allocation shown in this embodiment is a PRS allocation in which one RB (Resource Block) is made up of 12 REs and 14 OFDM symbols. A scheduler provided in the base station 10 allocates multiple consecutive or discrete RBs for communication to the terminal device 20. Here, a time unit consisting of 14 OFDM symbols is defined as one slot.

[0039] FIG. 12 is a diagram illustrating the allocation of PRSs, with the vertical axis representing frequency and the horizontal axis representing time. In FIG. 12, tiles with diagonal lines at the bottom right indicate the position of PRSs. Furthermore, tiles with dots are tiles where PRSs cannot be allocated. In this embodiment, plain tiles are empty REs where data information, control information, etc. are not allocated. That is, in this embodiment, PRSs and data (Physical Downlink Shared Channel: PDSCH) are not multiplexed. By not providing data information and control information (Physical Downlink Control Channel: PDCCH), interference from data and control signals transmitted from other TRPs or base stations 10 during positioning can be prevented. Furthermore, PRSs are not allocated to dotted tiles because downlink control information such as PDCCHs may be allocated thereto. Furthermore, PRSs are not allocated to locations where Physical Broadcast Channels (PBCHs), Primary Synchronization Signals (PSSs), or Secondary Synchronization Signals (SSSs) are allocated. In the 3GPP Rel. 15 standard, PDCCHs are allocated with one, two, or three symbols at the beginning of a slot. For this reason, the first symbol where a PRS is allocated may be determined according to the number of PDCCHs. Since the maximum number of PDCCH symbols is three, the symbol number of the symbol where a PRS is always allocated first in a slot may be fixed to 3, as shown in Fig. 12. Fig. 13 is a diagram showing a second example of PRS allocation according to the second embodiment. When the number of PDCCH symbols is two, the allocation shown in Fig. 13 is used.

[0040] FIG. 14 is a diagram illustrating a third example of PRS allocation according to the second embodiment. In FIG. 14, PRSs are not allocated to the first three symbols or the last two symbols. In 5G, uplink and downlink transmissions are time-multiplexed. For this reason, the last several symbols in a downlink transmission slot may become unusable for downlink transmission as a preparation section for analog devices for uplink reception or for uplink reception in the next slot. For this reason, it is possible to set the last PRS not to be transmitted. In FIG. 14, the last two symbols are used for uplink communication, so no PRS is transmitted. Furthermore, since the symbols used for uplink or downlink control information transmission change, multiple PRS allocations may be prepared and selected by a higher layer.

[0041] FIG. 15 is a diagram illustrating a fourth example of PRS allocation according to the second embodiment. A cyclic shift may be applied to the PRS so that the PRSs are orthogonal in the frequency domain. When PRSs are transmitted from multiple base stations 10, the terminal device 20 receives multiple PRSs, so it is important that the PRSs are orthogonal in frequency to prevent interference with each other. Therefore, as illustrated in FIG. 15, a cyclic shift may be applied to the PRSs in frequency. Alternatively, the amount of cyclic shift may be changed for each base station 10, so that the PRSs transmitted from each TRP are orthogonal in frequency. For example, in the example of FIG. 10, the PRS allocation transmitted from TRP1 may be the default allocation illustrated in FIG. 12, the PRS allocation transmitted from TRP2 may be the PRS allocation illustrated in FIG. 12 with a cyclic shift of 1 RE applied, the PRS allocation transmitted from TRP3 may be the PRS allocation illustrated in FIG. 12 with a cyclic shift of 2 RE applied, i.e., the PRS allocation illustrated in FIG. 15, and the PRS allocation transmitted from TRP4 may be the PRS allocation illustrated in FIG. 12 with a cyclic shift of 3 RE applied. The shift amount of the RE may be set by a PRS identification number, i.e., PRS_ID, which is an ID set by a higher layer, such as NPRSIDmod6.

[0042] 12, the positions of REs in adjacent OFDM symbols are shifted cyclically by 1 RE, which makes it easier to perform positioning with flat frequency characteristics.

[0043] FIG. 16 is a diagram illustrating a fifth example of PRS arrangement according to the second embodiment. As in the PRS pattern illustrated in FIG. 16, PRSs may be cyclically arranged at positions spaced apart by 2 REs or more in adjacent OFDM symbols. By using such an arrangement, robust PRS transmission is possible even in a frequency-selective transmission path. Note that a plurality of RE-shifted patterns as illustrated in FIG. 12 or 16 may be prepared, and an upper layer such as RRC (Radio Resource Control) may select a RE-shifted pattern and notify the terminal device 20. In this manner, PRSs compatible with various transmission paths can be selected.

[0044] FIG. 17 is a diagram illustrating a sixth example of PRS arrangement according to the second embodiment. As illustrated in FIG. 17, one base station 10 may transmit two or more patterns of PRS. The tile with diagonal lines in the lower left corner indicates the position of the PRS of the second pattern. If one pattern is called one resource, the base station 10 transmits two patterns of PRS. This setting enables highly accurate positioning using more PRSs. Furthermore, when positioning is performed using multiple panels, it becomes possible to set different PRS patterns for each panel. Note that when positioning is performed at a high frequency around 30 GHz, positioning accuracy is improved by performing the positioning in a line-of-sight environment, so the terminal device 20 may notify each TRP that it is in a line-of-sight environment.

[0045] Fig. 18 is a diagram illustrating a seventh example of an arrangement of PRSs according to the second embodiment. Fig. 19 is a diagram illustrating an eighth example of an arrangement of PRSs according to the second embodiment. As shown in Figs. 18 and 19, the arrangement of PRSs may be made to maintain orthogonality for each RB. Creating orthogonality in RB units makes it possible to increase the number of orthogonalities in the frequency domain.

[0046] In LTE, the PRS differs depending on the number of ports used for the PBCH. In this embodiment, different PRSs may be configured depending on the number of ports used for the PBCH. As described in Non-Patent Document 2, 3GPP TS 36.211 specifies that only one port is configured for the PBCH. In LTE, only one density is configured for the number of PBCH ports. However, in this embodiment, different positioning accuracies may be required in the high frequency band called FR2 in NR or the low frequency band called FR1, which ranges from 450 MHz to 6 GHz. Furthermore, because frequency, time, or power resources on the transmitting side are limited, it is necessary to change the PRS density. Therefore, multiple densities may be configured, and the density may be configured in a higher layer, such as RRC. The density mode may be set using a selection number as a bit or a parameter. For example, the selection number may be expressed as 0 = standard, 1 = low density, and 2 = high density. A parameter such as PRS_DENSITY indicating the PRS density may be provided to indicate the mode, such as PRS_DENSITY = "DEFAULT," "HIGH," or "LOW." Alternatively, a mode number may be set, multiple densities of PRS may be prepared, the density corresponding to each mode number may be determined in advance by a standard, and the density may be notified to the terminal device by RRC. Note that by setting the PRS density high, accurate positioning can be performed in a short time, and low-latency positioning can be achieved.

[0047] Fig. 20 is a diagram illustrating a ninth example of PRS arrangement according to the second embodiment. Fig. 20 illustrates an example of PRS arrangement in which the density of PRS is changed. In the PRS arrangement diagram of Fig. 20, PRSs are arranged at a higher density than the arrangement of Fig. 12. In Fig. 20, PRSs are arranged at a higher density, but orthogonality in frequency is lost.

[0048] FIG. 21 illustrates a tenth example of PRS placement according to the second embodiment. FIG. 21 illustrates an example of low-density PRS placement. While FIG. 21 provides a lower PRS density than the PRS placement in FIG. 12, frequency orthogonality is still achieved. PRSs may be placed in some or all of the active BWPs. When only a portion of the assigned BWPs is used, it is appropriate to use a BWP that is close to the center frequency of the assigned band and is less susceptible to interference from adjacent bands. For example, if the band is divided into four parts, BWP1, BWP2, BWP3, and BWP4, starting from the lowest frequency, accurate positioning can be achieved by using BWP2 or BWP3, or both BWP2 and BWP3. When multiple BWPs are used, measurements in each BWP may be performed during measurement gaps. During measurement gaps, no channels or signals are transmitted from each TRP or panel, and the terminal device performs observations. Only one BWP is used during the measurement gap, and a PRS is placed within the corresponding BWP. For example, if t2 > t1, then only the PRS included in BWP1 is transmitted during the measurement gap period from t1 to t2. If t4 > t3 > t2 > t1, then only the PRS included in BWP2 is transmitted during the BWP period from t3 to t4. When the bandwidth in use is large and transmission and reception processing is performed using the entire bandwidth, BWPs are used to divide the bandwidth, improving frequency utilization efficiency and minimizing interference with other users. The measurement gap setting is notified to the terminal device 20 using RRC or the like. The measurement gap may be used to synchronize between base stations and align the timing of transmission of reference signals used for positioning. Furthermore, since communication or positioning is performed using a wideband in NR, RSTD may be calculated when TRPs with different center frequencies or the same center frequency but different BWPs or bands are used. RSTD is generally observed using the following equation (1).In the following equation (1), RSTDi,1 is the time difference between TRPi, which is the ith TRP, and TRP1, which is the reference TRP. Ti-T1 is the difference in time when slots containing PRSs are transmitted from TRPi and TRP1. Ti-T1 is called the transmit time offset, and there is no offset between synchronized TRPs, so its value is zero. ni is the measurement error of the time of arrival in the terminal device. The speed of light is c. The position of the terminal device is indicated by coordinates (xt, yt), and the position of TRPi is indicated by (xi, yi). When positioning is performed in the terminal device, the system information block, PDCCH, PDSCH, or the like may include the position information of the base station and the transmit time offset. As described above, since RSTD can be calculated in the terminal device 20, the terminal device 20 may be equipped with a positioning function. Furthermore, information required for positioning may be transmitted from the terminal device 20 to the base station 10, and the base station 10 may perform the positioning process. In this case, the terminal device 20 includes a transmission processing unit, a positioning processing unit, and a reception processing unit, which correspond to the transmission processing unit 103, the positioning processing unit 106, and the reception processing unit 104 of the base station 10, respectively. In this case, the reception processing unit of the terminal device 20 receives a signal used for positioning transmitted from the base station 10, and the positioning processing unit of the terminal device 20 calculates the position of the terminal device 20 using the signal used for positioning. An example of a signal used for positioning is a PRS. Furthermore, although a TRP is used in the explanation of equation (1), equation (1) is not limited to a TRP and can be applied to any transmitting device that can transmit a PRS, and is a mathematical formula that can be applied to positioning using a panel.

[0049]

number

[0050] Furthermore, it is also possible to design PRSs for short slots called non-slots, which are composed of two symbols, four symbols, or seven symbols. FIG. 22 is a diagram illustrating an eleventh example of a PRS arrangement according to the second embodiment. FIG. 22 is a diagram illustrating an example of a PRS arrangement for a slot composed of two symbols. FIG. 23 is a diagram illustrating a twelfth example of a PRS arrangement according to the second embodiment. FIG. 23 is a diagram illustrating an example of a PRS arrangement for a slot composed of four symbols. FIG. 24 is a diagram illustrating a thirteenth example of a PRS arrangement according to the second embodiment. FIG. 24 is a diagram illustrating an example of a PRS arrangement for a slot composed of seven symbols. In the examples illustrated in FIGS. 12 to 24 , the RE in which the PRS is arranged is arranged downward to the right on the time-frequency coordinate plane, i.e., subcarriers with lower frequencies are used as the symbols become later. However, it is also possible to arrange it upward to the right on the time-frequency coordinate plane, i.e., subcarriers with higher frequencies are used as the symbols become later. Furthermore, a power difference between the PRS and other reference signals or channels may be set in a higher layer, such as RRC, to suppress interference caused by the PRS. Alternatively, the power of the PRS may be set higher than that of other signals, making the PRS less susceptible to interference than other signals. The comparison standard for the power difference may be the power of DMRS, CSI-RS, or PTRS (Phase Tracking Reference Signal). Alternatively, the difference with the power of the PDSCH may be used.

[0051] The sequence used for the PRS may be generated by a random number generator set by a seed number. The seed for the random number generator may be set in a higher layer using RRC or the like so that a different seed is set for each TRP. The random number generator may be, for example, a pseudo-random number generator using pseudo-random number generation as described in Chapter 5.2 of Non-Patent Document 2.

[0052] The PRS is implemented using QPSK (Quadrature Phase Shift Keying). The QPSK sequence used for the PRS may be generated by a random number generator set by a seed number. The seed for the random number generator may be set in a higher layer using RRC or the like so that a different seed is set for each TRP or panel. For example, a pseudo-random number generator using pseudo-random number generation, as described in Non-Patent Document 2, may be used as this random number generator. The shift register of the pseudo-random number generator specified by 3GPP is set by the parameter cinit. cinit depends on the symbol position or slot number where the PRS is allocated. The PRS may also be generated based on the PRS_ID set in a higher layer. The PRS_ID can be freely changed and may be set in a higher layer so that a different PRS is used for each cell, TRP, or panel. The value of PRS_ID may be set to, for example, 2^16, which is the same upper limit as the cell_ID. For example, in the case of NR, the value is 2^10 = 1024 (the number of cell_IDs is 1008). If the range of PRS_ID values ​​is {0, 1023}, the initial value setting for the shift register used for sequence generation may be made using the following equation (2). Note that the PRS may be other sequences such as Zadoff-Chu sequences instead of QPSK sequences. In this case, the sequence number of the Zadoff-Chu sequence is generated by a pseudo-random number generator.

[0053]

number

[0054] Here, ns is the slot number, and l is the symbol number within the slot. NCP is a variable that changes depending on the CP length, and may be set as NCP=0 for normal_CP and NCP=1 for extended_CP. The generated sequence may be masked with a coefficient specific to the TRP. If PRS_ID is not set by RRC, a default setting such as cell ID may be used.

[0055] Note that PRS sequences may be generated for up to the maximum number of RBs per OFDM symbol. That is, if the terminal device 20 can grasp the seed number for random number generation, it can grasp the PRS value for each RE. An alternative to this generation method is a method of generating a sequence for each number of RBs required by the PRS. That is, the sequence differs depending on the number of RBs, and more diverse PRS sequences can be generated than with the method described above. On the other hand, with the method described above, if the terminal device 20 can grasp the seed number for random number generation, it can grasp the PRS value allocated to the RE, so overhead is reduced. Either method may be used in this embodiment.

[0056] Furthermore, to avoid interference and provide resistance to frequency domain selectivity, PRS frequency hopping may be applied. Frequency hopping allows PRS to be transmitted while frequency-multiplexed with data for other terminal devices, rather than dedicating a wideband for a fixed period of time, as in FR2. Frequency hopping also provides time and frequency diversity. When frequency hopping is performed, the PRS is frequency-hopped according to a predetermined pattern. The hopping pattern may be performed in RB units. The PRS may be transmitted in slot units, with the number of consecutively transmitted slots specified by a higher layer. The hopping pattern is specified by a higher layer from among predetermined patterns, and the hopping pattern is notified to the terminal device via RRC. The terminal device may use the PRS to perform positioning in the band specified for each frequency hopping. When transmitting an aperiodic PRS, multiple slots containing only the PRS may be transmitted in burst format. Using multiple slots of PRS improves positioning accuracy.

[0057] The PRS may be transmitted periodically in the time domain as set by a higher layer. The PRS may be allocated every slot or every two slots. An offset may be added to the transmission start time. The PRS may be transmitted in units of multiple slots. A mode such as periodic, semi-persistent, or aperiodic may be set for the PRS and transmitted. For example, in the case of periodic, the period and the offset value at the start of transmission are set by RRC parameters or the like. The period and the offset value at the start of transmission are managed by a table or the like, and the table index is specified by a higher layer to set the period and offset value. In the case of semi-persistent, the time interval during which the PRS is periodically transmitted is specified by a higher layer. The aforementioned period is managed by a timer that records the elapse of time, and PRS transmission is automatically suspended when the period set by a higher layer or the like expires. Even during this period, the base station 10 may suspend PRS transmission and inform the terminal device 20 of the suspension of semi-persistent PRS transmission by DCI, MAC-CE, or the like. PRS transmission ends after the specified time has elapsed. The period may be specified in slot units. In aperiodic transmission, a PRS transmission request is sent from the terminal device 20 to the base station 10, and the base station 10 transmits the PRS after receiving an instruction from the terminal device 20. In this case, the PRS may be transmitted over multiple slots. To improve positioning accuracy, the base station 10 may set a period for transmitting the PRS every slot or every two slots to transmit at high density over time. Note that there is a possibility that the PRS and other channels or reference signals may collide in the transmission schedule. In such cases, the transmission priority between the PRS and other channels or reference signals must be determined by the standard. If a control channel such as PDCCH, a data channel such as PDSCH, or a reference signal such as an RS is scheduled in a slot or symbol in which the PRS is allocated, the PRS may be allocated with priority.For example, if a PDSCH is scheduled and allocated in advance in a slot or symbol where a PRS is allocated, the PRS may be allocated with priority, and the pre-scheduled PDSCH may not be transmitted. If a slot where a PRS is allocated overlaps with a PDSCH slot, the slot containing the PDSCH is not transmitted, and the slot containing the PRS is transmitted instead. In other words, multiplexing in the time and frequency domains, such as transmitting part of the data and part of the PRS, is not performed. The priority of PRS transmission may be lowered compared to channels containing important control information, such as the PDCCH. Furthermore, when a mode such as periodic, semi-persistent, or aperiodic is set as described above, if a collision occurs between a PRS and a PDSCH, the aperiodic mode may be set to the highest priority. The above-described priority may also be applied even if a mode such as periodic, semi-persistent, or aperiodic is not set for the PRS. Furthermore, if a collision occurs between PRSs, the priority may be determined based on the type of PRS. For example, when the arrangements of periodic, semi-persistent, and aperiodic PRS overlap, the priority order may be aperiodic > semi-persistent > periodic, that is, the priority of the aperiodic PRS may be set to be the highest.

[0058] In LTE, the minimum value of the periodicity is 160 subframes, but any of the following shorter periodicity values ​​may be included: 1, 2, 4, 8, 16, 32, 64, or 128 slots. The periodicity may also be set in non-slot units. The above-mentioned higher layer parameters related to the PRS may be managed using names such as resource setting, resource set, and resource. Hierarchical parameter management in this manner reduces overhead. Multiple resources are included in a resource set, and multiple resource sets are included in a resource setting. The resource setting may be called PRS-ResourceConfig in higher layers, and it manages resource sets and includes information such as the identification number of each resource set. It may also be managed according to TS 38.331. The resource setting may also specify the behavior of resources included in the resource set in the time domain, such as periodic, semi-persistent, or aperiodic. In this case, if the behavior in the time domain is defined in the resource setting, all resources included in the resource setting will have the same setting. The resource set defines parameters for multiple resources. For example, it includes resource identification numbers. Furthermore, if an aperiodic PRS is included, the resource set may indicate that all included PRSs are aperiodic. The resource may then specify the slot or frequency position where the PRS is allocated. Alternatively, instead of hierarchical parameters, RRC parameters for PRS configuration may be prepared. For example, RRC parameters such as PRS-config may include parameter information indicating the density of PRSs in time or frequency, or the time domain operation such as periodic, semi-persistent, or aperiodic as described above.

[0059] In addition, 3GPP uses antenna port numbers to apply identification numbers to reference signals. Antenna port numbers are numbers not used by other reference signals. Currently, as defined in TS38.211 for NR, numbers in the 1000s are used for PDSCH, numbers in the 2000s for PDCCH, numbers in the 3000s for CSI-RS, and numbers in the 4000s for SS or PBCH. For example, PRS may use port numbers in the 5000s. An identification number may also be created for a resource under a name such as PRS Indicator. Note that PRS may be used in low frequency bands below 6 GHz, known as FR1 in NR, assuming the use of wide beams. Since FR1 uses relatively wide beams, there is no need to associate PRS with beam numbers, and PRS may be transmitted over a wide range, like a broadcast signal. In a frequency band called FR2, which is higher than FR1, relatively narrow beams are used. Therefore, the base station 10 needs to transmit to the terminal device 20 beam information on which the PRS will be transmitted so that the terminal device 20 can accurately receive the PRS. In this case, the base station 10 may associate the beam selected to transmit the SSB used during initial connection with the beam transmitting the PRS. Alternatively, the base station 10 may associate the beam used for beam management, which is suitable for transmitting the selected CSI-RS or SSB, with the beam transmitting the PRS. The beam information is indicated using, for example, the SSBRI or CRI. By performing positioning using beams, angle information can be obtained accurately and in a short time, enabling low-latency positioning.

[0060] Furthermore, a process may be performed in which a periodically transmitted PRS is not transmitted at a specified PRS timing. This is intended to prevent interference with other signals or frequencies during transmission interruption. FIG. 25 is a diagram illustrating an example of muting according to the second embodiment. In the muting of FIG. 25, a portion of the PRS in the indicated section is not periodically transmitted. FIG. 26 is a diagram illustrating another example of muting according to the second embodiment. For example, when there are four opportunities to transmit a PRS, the bitmap is used to represent "1001." By determining the number of transmissions subject to muting in this manner, it becomes possible to periodically interrupt some PRS transmissions using the bitmap.

[0061] In NR, CSI-RS is generally used for beam management, but beam sweep may be performed using PRS for positioning beam management. Positioning can also be performed using other RSs without using PRS. For example, CSI-RS is used for beam management, etc., to direct a highly accurate beam toward the location of the terminal device 20. In this case, CSI-RS is used for positioning, and the CSI-RS port number used for positioning may be notified to the terminal device 20. In this embodiment, NZP-CSI-RS defined in Non-Patent Document 2 and the like is used as an example. In this case, the terminal device 20 calculates the difference in reception timing of CSI-RS received from multiple base stations 10, and can determine its location in the same way as when positioning is performed using PRS. For example, in FIG. 10, TRP1 may be configured to use CSI-RS port 1, TRP2 to use CSI-RS port 2, TRP3 to use CSI-RS port 3, and TRP4 to use CSI-RS port 4. In NR, the position where the CSI-RS is arranged is determined by the maximum number of ports, so the base station 10 needs to notify the terminal device 20 of the maximum number of ports. Also, some CSI-RS ports are multiplexed using OCC (Orthogonal Cover Code), but in positioning such as OTDOA, the CSI-RS arrives at the terminal device 20 with a time lag, so it is not appropriate to use ports multiplexed by OCC. Using CSI-RS ports where REs do not overlap in time and frequency can achieve optimal positioning accuracy. When using CSI-RS, by informing the terminal device 20 in a higher layer that the CSI-RS will be used for positioning, the terminal device 20 will know that the CSI-RS will be used for positioning. Below is an example in which multiple parameters are included in the higher layer for positioning.

[0062] When using CSI-RS, the CSI-RS for positioning may be configured in a higher layer. For example, positioning parameters may be configured so that the CSI-RS is arranged so as not to overlap with CSI-RS used for purposes other than positioning in time symbols or frequency REs. A parameter that indicates positioning, such as CSI-RS-Resource-Positioning, may be prepared in a higher layer, such as RRC. To indicate that the CSI-RS is used for positioning, the resource setting, resource set, or resource may indicate that the CSI-RS is used for positioning. To use the CSI-RS for positioning in a higher layer, a flag named "positioning" or a flag such as PRS may be set in the resource setting, resource set, or resource, and a value of 1 indicates that the CSI-RS is used for positioning, while a value of 0 indicates that the CSI-RS is used for CSI observation. A muting function may also be used for CSI-RS. By using a bitmap on a slot-by-slot basis, it is possible to specify in which slot the CSI-RS can be transmitted. Using the muting function makes it possible to avoid interference and perform positioning. Note that when PRS or CSI-RS is transmitted from multiple TRPs, panels, or base stations, the CP (Cyclic Prefix) length of the transmitted OFDM signal is assumed to be the same. For example, 3GPP TS36.211 specifies normal CP and extended CP, with the extended CP being a longer CP. When PRS or CSI-RS is simultaneously transmitted by OFDM signals from multiple base stations 10 with flag values ​​TRP or flag values ​​panel, it is appropriate for the CP length of all waveforms to be the same in order to accurately calculate the time difference between the received multiple PRS or CSI-RS signals. Furthermore, using CPs of the same length eliminates the need to read the CP length from control information during calculations, reducing the overhead required for control information.

[0063] Furthermore, when positioning is performed using PRS, it is appropriate to use the same numerology, i.e., subcarrier spacing, for the PRS transmitted from each TRP. Since the subcarrier spacing is unified between the PRSs from each TRP, RSTD calculation becomes easier. When calculating its own location information in a UE using an OTDOA method or the like, the location information of the terminal device 20 may be notified to the base station 10 from the terminal device 20 using a CSI report or the like. This is because, if the base station 10 can periodically grasp the location information, it becomes possible to manage and select appropriate beams in beam management and the like. Furthermore, in MU-MIMO and the like, being able to grasp the location of the terminal device 20 allows optimal scheduling of the terminal device. Furthermore, positioning may be performed using PRS in FR1 and CSI-RS in FR2. As described above, wide beams are used in low frequency bands, and the UE cannot know the transmitted beam information. Therefore, it may receive the broadcasted PRS and perform RSTD calculations. In high frequency bands, beam management using CSI-RS is performed, and a beam appropriate for the UE is set, so positioning using CSI-RS provides high positioning accuracy. Although the above description describes using CSI-RS for beam management, SSB may also be used for beam management. Periodic transmission of the positioning PRS or CSI-RS may be interrupted using DCI (Downlink Control Information). This is because periodic communication may cause data transmission interruptions, and therefore includes a process for immediately interrupting transmission. When the positioning PRS, CSI-RS, or SSB is transmitted, the RNTI (Radio Network Temporary Identifier), which is an identification number assigned to the terminal device, may be a C-RNTI (Cell-RNTI), a CS-RNTI (Configured Scheduling RNTI), or an SP-CSI-RNTI (Semi-Persistent CSI RNTI).

[0064] A zero-power CSI-RS (ZP-CSI-RS) may be used as an interference measurement CSI-RS for the CSI-RS used in NR. For example, if interference occurs with a base station 10 of an adjacent cell, the ZP-CSI-RS is transmitted while the base station 10 of the adjacent cell is transmitting a positioning CSI-RS, thereby preventing interference with the base station 10 of the adjacent cell. As with the PRS, a PDSCH does not need to be allocated to the slot in which the positioning CSI-RS is allocated. This is to reduce interference caused by the PDSCH. Positioning using a DMRS may also be performed. Since multiple symbols are allocated within a slot, it is suitable for positioning. Furthermore, a power difference between the positioning CSI-RS and other reference signals or channels may be set in a higher layer such as RRC to suppress interference caused by the CSI-RS. Alternatively, the power of the CSI-RS may be set higher than that of other signals, making the CSI-RS less susceptible to interference than other signals. The comparison standard for the power difference may be the power of DMRS, CSI-RS for channel estimation or interference measurement, or PTRS, or the difference with the power of PDSCH.

[0065] When multiple panels are used, PRSs are received from the multiple panels. Since the multiple panels are connected to the base station 10, multiple TRPs exist within the same cell. In this case, the PRS_ID may be changed for each panel to set different PRS sequences. Also, since the positioning accuracy decreases if there is an obstacle in front of the panel, a flag may be used to indicate whether or not to transmit a PRS for each panel. This flag may be notified to the terminal device 20 using a control signal in an upper or lower layer. The parameters used in the upper layer may be RRC or MAC-CE, and DCI may be used in the lower layer.

[0066] Positioning using OTDOA from the IDLE state or INACDTIVE state is also possible. The terminal device 20 starts positioning while monitoring paging information included in the PDCCH transmitted from the base station 10 or the PDSCH specified in the PDCCH. Note that a notification is sent to the terminal device 20 in the paging information, and the terminal device 20 decodes the notification and reads the SIB (System Information Block). The SIB is included in the PBCH and PDSCH.

[0067] The SIB includes information necessary for OTDOA. For example, when a base station 10 with multiple cells is used in OTDOA, the SIB may include the cell ID of the cell being used. It may also include information on the reference cell. When multiple panels are used for positioning in the same cell, the SIB may include the panel ID of the panel being used or the ID of the panel being used as the reference. When beams are emitted from each panel, each panel may be linked to a group, and the SIB may include information on the group to which the beam belongs. The SIB used for positioning may be given a name indicating the type of SIB so that it can be identified as a positioning SIB.

[0068] Furthermore, when multiple panels are used in the same cell, the SIB may include the ID of the cell and the number of panels used for positioning. The positioning instruction may include information for positioning, information indicating that a positioning SIB is to be received, and the like. The terminal device 20 receives the positioning SIB. The positioning SIB information may be transmitted periodically, or may be transmitted in advance when the base station 10 instructs the terminal device 20 to perform positioning. Furthermore, information on the time and frequency resources for transmitting the PRS may be included in the SIB. The time and frequency resources for the periodically transmitted PRS may be described. Furthermore, when the PRS is transmitted aperiodically, the time and frequency resources for aperiodically transmitting the PRS may be specified.

[0069] After receiving a PRS, the terminal device 20 in the IDLE or INACTIVE state calculates the difference in reception time of multiple PRSs as described above, and reports the calculation result and / or the positioning result to the base station 10 according to an instruction from the base station 10 or at the discretion of the terminal device 20. Furthermore, when positioning is performed using multiple panels or TRPs, the TRPs or panels may be located close to each other and may not be distinguishable from the terminal device 20. In such cases, it may be possible to determine that the panels or TRPs are located close to each other using QCL (Quasi Co-Location) information or measurement results. Furthermore, when the panels or TRPs are located close to each other, it may be possible to average the measurement results or calculate the maximum and minimum values ​​and report them to the base station 10.

[0070] The LMF transmits an OTDOA_INFORMATION_REQ to the NG_RAN_NODE, starting positioning using OTDOA. In this case, the OTDOA_INFORMATION_RESPONSE is transmitted from the LMF to the NG_RAN_NODE, and the information may include PRS configuration information. For example, the information may include the carrier frequency, PRS band, frequency offset, PRS time offset or transmission interval, the number of consecutively transmitted slots, the number of antenna ports used, whether the period setting is periodic / semi-persistent / aperiodic, beam information or beam pair number on the base station 10 or terminal device 20 side, and selected codebook information. The report information may also include the SFN (Slot Frame Number), antenna or panel position, PRS muting information, PRS hopping pattern, and PRS density information such as standard, high density, or low density. A value indicating the subcarrier spacing used may also be included. CP (Cyclic Prefix) information may also be transmitted. In addition, since CSI-RS or PRS is transmitted from different TRPs in OTDOA, information is required to enable the UE to understand the relationship between the TRP and the PRS or CSI-RS. For this purpose, the PRS ID previously set in each TRP or the parameter nID for generating the CSI-RS defined in TS 38.211 may be notified from a higher layer. Such information may be notified using RRC, or the PRS_ID or parameter nID of the PRS or CSI-RS transmitted from each TRP may be included in the OTDOA assistance data transmitted from the location server.

[0071] NR uses TDD (Time Division Duplexing), and as described in Chapter 11.1.1 of Non-Patent Document 3, symbols within a slot are set to "D" for downlink, "U" for uplink, or "F" for flexible symbols. PRS may be transmitted only using symbols set for downlink as "D." Alternatively, if not used by other symbols, "F" symbols may also be used to transmit PRS.

[0072] Furthermore, numerology such as subcarrier spacing may change during measurement. In NR, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 480 kHz are provided, and these values ​​are set not to change during positioning to maintain accuracy during positioning. Furthermore, PRSs with different numerologies may be transmitted to the terminal device 20 in the frequency domain. For example, if 20 RB resources are allocated to the terminal device 20 for positioning, it may be set so that 10 RBs are sent at 15 kHz and 10 RBs are sent at 120 kHz. All numerologies may be the same, but if different numerologies are used, frequency errors are included in the positioning calculation.

[0073] Note that, when performing positioning, location information may be defined using a predetermined grid. The grid is determined in advance, and beam candidates are prepared so that the base station 10 can radiate a beam to the center of the grid. For example, when performing positioning in a stationary environment, once grid information is obtained, the terminal device 20 selects a beam and reports it to the transmitting side, allowing the transmitting side to determine the location of the terminal device 20. This method is effective in locations with a fixed installation environment. SSBs can be used as another example of positioning in the IDLE or INACTIVE state. The terminal device 20 may receive SSBs from multiple base stations 10 and / or multiple panels or TRPs. The terminal device 20 may retain information regarding the reception times of the SSBs. This information may be, for example, the difference between the reception times of multiple SSBs. This, for example, eliminates the need for the base station 10 to transmit PRS-related settings to the terminal device 20, thereby reducing the amount of signaling between the base station 10 and the terminal device 20. The terminal device 20 may derive its own location using information regarding the reception times of the SSBs. The base station 10 and / or the panel or TRP may broadcast information about the location of its own base station and / or its own panel or TRP, or may individually notify the terminal device 20 of this information. The terminal device 20 may use this information about the location to derive the location of its own terminal device. This, for example, eliminates the need for the terminal device 20 to transmit measurement results to the base station 10, thereby reducing the amount of signaling between the base station 10 and the terminal device 20 and eliminating the need to resume communication between the terminal device 20 and the base station 10, thereby enabling rapid positioning in the communication system. As another example, the base station 10 may derive the location of the UE using information about the reception time of the SSB. The terminal device 20 may notify the base station of information about the reception time of the SSB. This notification may, for example, be included in a measurement result report from the terminal device 20 to the base station 10 or may be included in a different signaling. The base station 10 may derive the location of the terminal device using information about the reception time of the SSB. This makes it possible to reduce the load on the terminal device 20 due to position derivation, for example.Furthermore, the first and second embodiments may be combined. In the first embodiment, angle information is obtained from a selected beam and positioning is performed using distance information. In the second embodiment, RSTD is calculated from the reception times of reference signals transmitted from multiple transmitters, and positioning is performed. The average of the positions obtained by both methods may be calculated. Furthermore, when positioning is performed using multiple base stations, some base stations may use the method described in the first embodiment, and the other base stations may use the method described in the second embodiment. As described above, the reference signals used for positioning are set to have periods of periodic, semi-persistent, or aperiodic. However, the position information of the terminal device 20 after positioning may also be notified from the terminal device 20 to the base station, or from the base station to the terminal device 20, in any of the periodic, semi-persistent, or aperiodic formats. Periodic position notification, such as in the periodic or semi-persistent format, improves the accuracy of location-sensitive services such as emergency notifications. In the aperiodic format, the base station or terminal device 20 that desires to receive a location information report requests a location information report, and the location information is reported at a time set in an upper or lower layer. Aperiodic location information reporting is an effective reporting method when a base station or terminal device 20 urgently needs location information. When periodic reporting is selected, the base station or terminal device 20 reports the calculated location information in accordance with a cycle determined by a higher layer, for example, a cycle based on slots. When semi-persistent reporting is set, the base station or terminal device 20 reports the calculated location information in accordance with a cycle determined by a higher layer, for example, a cycle based on slots, for a period determined by the higher layer. The above-mentioned reporting method may also be called a periodic position report, semi-persistent position report, or aperiodic position report.

[0074] Embodiment 3 In UTDOA, a terminal device 20 transmits positioning signals to multiple base stations 10 or TRPs, and the base stations 10 or TRPs cooperate to calculate the difference in reception time of the positioning signals transmitted from the terminal device 20 and use the calculated difference in reception time for the terminal device 20. In this case, the terminal devices 20 may transmit signals simultaneously or at a fixed timing. The signal transmitted from the terminal device 20 may use SRS or PRS used in the downlink. In NR, OFDM or DFT-s-OFDM is used in the uplink, but when PRS, SRS, DMRS, or DFT-s-OFDM is used for OFDM, SRS or DMRS may be used.

[0075] In NR, either OFDM or DFT-s-OFDM is used in the uplink. DFT-s-OFDM features a lower PAPR (Peak to Average Power Ratio) than OFDM, allowing for transmission at higher power levels than OFDM. Since low uplink power reduces positioning accuracy, DFT-s-OFDM may always be used as the default for positioning. Since the frequency or reference signal settings differ between DFT-s-OFDM and OFDM in the uplink in NR, it is desirable for one method to always be set as the default during positioning for the eNB. A mechanism for switching to ODFM may also be provided if sufficient power is available. This is an example embodiment applicable to the E-CID, OTDOA, or UTDOA method.

[0076] It should be noted that while a beam search is being performed during positioning, the search may fail. In such a state, the terminal device 20 may notify the base station 10 that the beam search has failed. Also, it is possible that the beam search may fail when the terminal device 20 moves to another TRP or into a cell during positioning. Even in this case, the terminal device 20 may notify the base station 10 that the search has failed and stop positioning. Also, in beam recovery, the terminal device 20 may request the base station 10 to change the mutual beam pair between the base station 10 and the terminal device 20, but positioning is not performed during beam recovery.

[0077] Embodiment 4 In the ECID scheme, the distance between the base station 10 and the terminal device 20 may be calculated in accordance with the TA (Timing Advance) calculation method. Furthermore, in UTDOA, PRACH may be used for uplink signals. In this embodiment, the configuration of the PRACH used for ECID and PRACH will be described. The BS can request the terminal device 20 to transmit a PRACH, which is called a PDCCH_order, and include this request in the PDCCH. At this time, the PDCCH may include a PRACH configuration for positioning. It may also be indicated that the PDCCH is a PDCCH_order for positioning. A search space indicating the frequency and time resources in which DCI is placed within the PDCCH may be configured for positioning. Furthermore, the CRC of the PDCCH is scrambled by the RNTI, but the RNTI for positioning may also be used. By specially configuring the location where the PDCCH CRC or DCI is placed for positioning in this way, it is implied that positioning information is included for the terminal device 20 after receiving the PDCCH. The TA is calculated using the PDCCH_order and PRACH. Normally, the base station 10 transmits an RAR (Random Access Response) after receiving a PRACH, but may not transmit an RAR if it receives a PRACH for positioning. Since positioning can be performed by receiving the PRACH for positioning, there is no need to perform the subsequent RA process. After transmitting the PRACH for positioning, the terminal device 20 may not receive an RAR from the base station 10. As the PRACH configuration for positioning, frequency and time resources or a preamble format are set. Furthermore, the PRACH configuration for positioning may be set in advance to be different from PRACH configurations for other uses.

[0078] The configuration of the positioning PRACH transmitted in the IDLE or INACTIVE state may be configured in the RRC_CONNECTED state. The configured parameters include the PRACH position in frequency and time, the preamble format, and the period if the PRACH is transmitted periodically, configured in the RRC_CONNECTED state. These settings are also applied to the positioning PRACH when the state changes to IDLE or INACTIVE. The IDLE or INACTIVE state settings may be configured using an SIB. Information used for positioning may also be included in the paging information. For example, PRACH configuration information may also be included. Alternatively, only some of the information may be configured. For example, only the transmission timing may be configured.

[0079] When an RNA (RAN based Notification Area), which is the range of paging sent in the INACTIVE state, is applied, the PRACH configuration for positioning sent in INACTIVE may be set for each RNA. It may be set differently from the PRACH configuration for other uses. Furthermore, the PRACH configuration for positioning sent in IDLE may be set for each paging area. It may be set differently from the PRACH configuration for other uses. Furthermore, when multiple TRPs are used in the same cell, a special configuration may be used. The PRACH configuration for positioning may be set for each cell. It may be set differently from the PRACH configuration for other uses.

[0080] The PRACH for positioning may be placed in time and frequency resources set aside for positioning. A special sequence or preamble format may be prepared for positioning. Multiple candidates may be prepared so that the PRACH band can be selected.

[0081] Embodiment 5 FIG. 27 is a diagram illustrating positioning performed by switching between LTE and NR according to a fifth embodiment. Since the coverage of an LTE cell is wide, positioning may be performed within an NR cell by referring to positioning information obtained from LTE. Alternatively, positioning may be performed by switching between the NR and LTE positioning methods. The switching is instructed by a higher layer.

[0082] Embodiment 6 FIG. 28 is a diagram illustrating an example of an arrangement of positioning reference signals according to a sixth embodiment. FIG. 28 is an arrangement diagram of positioning reference signals with the vertical axis representing frequency and the horizontal axis representing time. In this embodiment, a case will be described in which positioning reference signals are arranged at positions illustrated in FIG. 28. In FIG. 28, OFDM symbols hatched with multiple dots indicate positioning reference signals. In the example illustrated in FIG. 28, positioning reference signals are arranged every other RE in the third OFDM symbol in the time axis direction. Note that in FIG. 28, only symbols used for transmitting positioning reference signals are inserted in the third OFDM symbol in the time axis direction, and data symbols, control signals, and other types of reference signals are not inserted. In addition, any signal may be arranged in the symbols indicated by diagonal lines in FIG. 28 where no reference signal is arranged.

[0083] FIG. 29 is a diagram showing the waveform of a signal within one OFDM symbol in which the positioning reference signal shown in FIG. 28 is allocated. FIG. 29 shows that the transmission waveform is repeated in units of half one OFDM symbol time. As an example, one OFDM time is divided into two, a first 0.5 OFDM symbol time and a second 0.5 OFDM symbol time. The waveform of the signal in the first 0.5 OFDM symbol time and the waveform of the signal in the second 0.5 OFDM symbol time have the same shape. In other words, in FIG. 29, waveforms with similar amplitudes and phases are repeated in one OFDM symbol.

[0084] Fig. 30 is a diagram showing a comparative example in which a positioning reference signal is arranged over multiple symbols. When the waveform of a signal in the first 0.5 OFDM symbol time as shown in Fig. 29 is the same as the waveform of a signal in the second 0.5 OFDM symbol time, synchronization error is likely to occur when performing symbol synchronization. For this reason, it is necessary to transmit a positioning reference signal over multiple symbols as shown in the comparative example in Fig. 30. Furthermore, synchronization error is also likely to occur in signals in which signals with equal power characteristics are repeated multiple times within one OFDM symbol interval.

[0085] To solve the problem that synchronization loss is likely to occur when performing symbol synchronization, in this embodiment, the base station 10 switches beams for each interval in which the same waveform occurs within one OFDM symbol and transmits a signal, thereby preventing the same waveform from being observed repeatedly at the terminal device 20. The terminal device 20 receives signals for each beam switched for each interval. With this method, the terminal device 20 does not receive the same waveform, and therefore synchronization loss in the terminal device 20 can be suppressed.

[0086] FIG. 31 is a diagram illustrating an example of switching beams for each interval in which the same waveform occurs within one OFDM symbol according to the sixth embodiment. FIG. 31 illustrates an example in which the same waveform occurs twice within one OFDM symbol. In FIG. 31, two beams are transmitted from the base station 10, designated as beam 1 and beam 2. In FIG. 31, beam 1 and beam 2 are assumed to point in different directions, i.e., different spatial directions. The directions of beam 1 and beam 2 are adjusted by the base station 10. The base station 10 can direct the beams using an analog beam or a digital beam using digital precoding. The terminal device 20 cannot receive signals at maximum power unless it uses a receiving beam directed in the direction of beam 1 or beam 2 transmitted from the base station 10.

[0087] In the example shown in FIG. 31 , beam 1 is used to transmit signal A in the first half of one OFDM symbol time. Beam 2 is used to transmit signal B in the second half of one OFDM symbol time. If the beam is not switched for each interval in which the same waveform occurs within one OFDM symbol, the terminal device 20 will receive signals A and B within one OFDM symbol. On the other hand, if the beam is switched for each interval in which the same waveform occurs within one OFDM symbol, the terminal device 20 will receive only signal A when adjusting the direction of the receiving beam to receive a signal transmitted by beam 1. Also, if the terminal device 20 adjusts the direction of the receiving beam to receive a signal transmitted by beam 2, it will receive only signal B. For example, in FIG. 31 , if the terminal device 20 receives using beam 3, it will be able to receive the signal transmitted by beam 1. When beam 3 is used, the received power of the signal transmitted by beam 2 at the terminal device 20 is lower than the received power of the signal transmitted by beam 1. On the other hand, if the terminal device 20 receives using beam 4, it will be able to receive the signal transmitted by beam 2. When beam 4 is used, the received power of the signal transmitted from beam 1 at the terminal device 20 is smaller than the received power of the signal transmitted from beam 2. That is, the terminal device 20 cannot see the repeated signal in one OFDM symbol interval or in an interval where signals with equal power characteristics are repeated multiple times.

[0088] In this embodiment, as described above, no other signals are allocated to the OFMD symbol into which the positioning reference signal is inserted. Since the positioning reference signal is allocated to a predetermined position, if the terminal device 20 can obtain information about the positioning reference signal, such as the allocation interval of the positioning reference signal in the frequency domain and the sequence used as the reference signal, the characteristics of the signal in one OFDM section can also be known in advance, and therefore demodulation is possible even when only signal A or signal B is received, as shown in FIG. 31. Note that when the sequence used for the reference signal is a PN (Pseudo Noise) sequence, a value such as C_init used to initialize a shift register for sequence generation may be notified to the terminal device 20 as information about the positioning reference signal. Furthermore, when the sequence changes depending on the slot, symbol number, or relative position from other reference signals in which the positioning reference signal is allocated, the above-mentioned parameters may be notified to the terminal.

[0089] Note that when base station 10 switches transmission beams within one OFDM symbol as in this embodiment, the beam sweep time of base station 10 is shorter than when the beam is not switched within one OFDM symbol. For example, in a conventional method, if one same beam is used in one OFDM symbol period to sweep and transmit 64 beams, base station 10 requires at least 64 OFDM symbol times to transmit the 64 beams. In addition, if time is required to switch beams, base station 10 requires more than 64 OFDM symbol times to transmit the 64 beams. However, as an example of this method, when base station 10 sweeps 64 beams using two beams within one OFDM symbol, beams are switched every 0.5 symbol times, so transmission of the 64 beams is completed in at least 32 symbol times. If terminal device 20 sets a fixed reception beam while base station 10 is beam-sweeping the reception beams, it can observe the received power of beams radiated in multiple directions transmitted from base station 10 within one OFDM symbol. Since the beam sweep time is shortened, the base station 10 may increase the number of beams to be swept, i.e., the number of resources. During beam sweeping, the base station 10 needs to set the direction or range from which the beam sweep will begin in order to shorten the time required for beam sweeping and increase the efficiency of the beam sweep. As shown in FIG. 10 , when the terminal device 20 performs positioning using multiple base stations or TRPs, the terminal device 20 may notify surrounding base stations of the beam sweep results of the reference TRP. Here, the beam sweep results may be, for example, the received power of each beam acquired by the terminal device 20 when the base station 10 is beam sweeping. Alternatively, the beam sweep results may be, for example, the transmission beam number selected after the beam sweep. For example, using the example of FIG. 10 , the terminal device 20 may notify TRPs 2, 3, and 4 of the beam sweep results of TRP1 via the server 200. Alternatively, the terminal device 20 may notify the TRPs 2, 3, and 4 using a broadcast channel such as a PBCH (Physical Broadcast Channel).

[0090] Various methods can be considered for notifying the terminal device 20 of such setting notification information, which is information notifying that a beam will be switched within one OFDM symbol, from the base station 10 to the terminal device 20. The base station 10 may notify the terminal device 20 of the setting notification information by including the setting notification information in an upper layer signal and transmitting the upper layer signal including the setting notification information to the terminal device 20. The notification may be a flag, or an RRC parameter of the upper layer signal may be used. The method of transmitting information notified to the terminal device 20 is not limited to a method using RRC parameters, and methods other than RRC parameters may be used.

[0091] Furthermore, the server 200 that performs positioning may notify the terminal device 20 of the setting notification information. For example, the server 200 may notify the terminal device 20 of the setting information using LPP (LTE Positioning Protocol). Alternatively, the server 200 may notify the terminal device 20 using a protocol defined by NRPPa. The setting information may be notified via the base station 10. For example, information may be transmitted from the LMF to the base station 10 via NRPPa. Alternatively, a server equipped with a positioning function for the downlink and a server equipped with a positioning function for the uplink may be installed separately. By installing these servers, the processing power can be distributed, enabling the calculation time required for positioning to be reduced.

[0092] Embodiment 7 When a terminal device 20 performs positioning using positioning reference signals transmitted from multiple base stations 10 via downlink or uplink, it is necessary to manage beam information. Examples of beam information include beam power and beam irradiation direction. Furthermore, when a reference signal is transmitted via a beam, the beam information includes, for example, the frequency at which the reference signal is transmitted and the position of the reference signal in the time and frequency domains. The time and frequency domain positions of the reference signal are predetermined for each beam, and the terminal device 20 can estimate the strength of the received power by measuring the received signal at the position where the reference signal is transmitted. When a downlink positioning reference signal is transmitted from each of multiple base stations 10 to the terminal device 20 as shown in FIG. 10 and the terminal device 20 performs positioning, it is necessary for the base station 10 or the terminal device 20 to manage beam information for transmitting each positioning reference signal. In this embodiment, the TRP in FIG. 10 is referred to as a base station 10. The base station 10 may be located in the same cell as the terminal device 20 or in another cell. In such a case, a resource set may be allocated to each base station 10. Note that a resource set is generally used to configure CSI-RS, which is a reference signal used in the downlink, or SRS, which is a reference signal used in the uplink.

[0093] The resource set used for positioning may be configured as a resource set different from CSI-RS. Special settings such as muting or periodic PRS transmission for positioning are made for each resource set, so it may be set as a resource set different from CSI-RS, etc. Note that the muting setting may be set on a resource set basis or on a resource basis.

[0094] The resource set may be applied to a positioning reference signal in the uplink. In 3GPP LTE, SRS is used as a positioning reference signal in the uplink. The SRS used for positioning is referred to as a positioning SRS here. For example, as described above, the RRC parameter "usage" may be set to "Positioning." Furthermore, as described above, the server or the positioning function may notify the terminal device 20 of the setting information for the usage used in the RRC parameter. In this case, rather than using it as an RRC parameter, the usage is set as higher-level information of the information notified from the server or the positioning function. The beam information of the SRS may be defined as "resource," and multiple beam information may be defined as a resource set. Furthermore, in the case of positioning using the uplink, the terminal device 20 transmits a positioning reference signal to multiple base stations 10. The base station 10 records the reception time of the positioning reference signal transmitted from the terminal device 20, and the multiple base stations 10 refer to each other's reception time information to determine the position of the terminal device 20 from the time difference between the reception times with other base stations 10. The positioning reference signal is not limited to an SRS, and an uplink PRS may also be used. The positioning reference signal also includes location information in the frequency domain and time domain where the SRS transmitted from the terminal device 20 is located using a beam corresponding to each resource. That is, the base station 10 measures the received power of the beam using the SRS located at the frequency domain and time domain position where the SRS transmitted from the terminal device 20 is located. The location information in the frequency domain and time domain where the SRS transmitted from the terminal device 20 is located may be information in units of multiple symbols or information in units of one symbol.

[0095] When the terminal device 20 transmits a reference signal to multiple base stations 10, it is necessary to link the reference signal transmitted by the terminal device 20 with the destination base station 10 and the beam number or resource number, which increases the amount of control information required. When the amount of control information increases, transmission time is required and the bandwidth, number of symbols, and number of bits required for the control information increase.

[0096] Here, a reference signal may be transmitted by linking the resource set of the SRS with the destination base station 10. If the resource set of the SRS is linked with the destination base station 10, the information transmitted to the terminal device 20 is only information related to the resource set, such as the identification number of the resource set, and therefore the amount of control information can be kept to a minimum.

[0097] The settings related to the resource set and resources of the SRS may be performed using RRC. Note that a setting method other than RRC may also be used. The settings related to the resource set and resources of the SRS may be performed individually by each base station 10. Furthermore, setting information may be notified to the terminal device 20 from a server or a function that performs positioning.

[0098] The terminal device 20 only needs to transmit the resource set and the SRS according to the resource-related settings. Therefore, it is only necessary to set the same number of resource sets as the number of expected base stations 10.

[0099] When the terminal device 20 determines the beam to be used when transmitting the positioning SRS, which is the SRS used for positioning in the uplink, the terminal device 20 needs to perform beam sweeping to select an appropriate beam. However, when the terminal device 20 performs beam sweeping, it requires time to sweep the determined range, which increases the time required for positioning. Therefore, in order to omit the beam sweeping or reduce the time required for the beam sweeping, the beam information used when transmitting the positioning SRS may be associated with the beam information used when the reference signal or synchronization signal in the downlink or uplink has already been used. The association of the beam information may be performed, for example, by the base station 10 or a server. By linking the beam information in this manner, it is possible to obtain the effect of omitting the beam sweeping or reducing the time required.

[0100] Here, the linking of the positioning SRS with other reference signals will be described in detail. The reference signal or synchronization signal used in the downlink may be CSI-RS, SSB, PRS, or TRS (Tracking Reference Signal). When transmitting the reference signal or synchronization signal, the base station 10 transmits them using any of the beams. At this time, if the beam of the positioning SRS in the uplink is linked to the beam that transmitted the reference signal or synchronization signal in the downlink, the terminal device 20 may transmit the beam of the uplink positioning SRS that is linked to the beam used to transmit the reference signal or synchronization signal in the downlink.

[0101] In the uplink, a positioning SRS may be transmitted using a beam associated with an SRS used for purposes other than positioning. In 3GPP NR, Release 15 SRS is divided into use cases: UL codebook-based, UL non-codebook-based, UL beam management, and Antenna switching. The above-mentioned use cases are configured for a resource set. Then, unique parameters are configured for each of the above-mentioned use cases and notified to the terminal device 20. The beam used to transmit the positioning SRS can be set to the beam direction for SRS positioning using the beam direction used in the above-mentioned use case. Setting the beam direction of the SRS used for other use cases in this way eliminates the need for beam sweeping, thereby shortening the time required to determine the appropriate direction. Setting the beam direction of the SRS used for other use cases also reduces the amount of control data sent to the base station 10 and a server equipped with a positioning function.

[0102] When a positioning CSI-RS is used as a PRS, possible reference signals to which spatial information is linked include SSB, SRS, and uplink PRS. Furthermore, a downlink PRS may be linked to spatial information of a DMRS. Here, the spatial information of a DMRS refers to the direction of a beam through which the DMRS is transmitted. For example, the direction of a beam through which the DMRS is transmitted is linked to the beam number of another downlink reference signal. Alternatively, for example, the direction of a beam through which the DMRS is transmitted is linked to a QCL state between the PRS and an RS including the DMRS and another DMRS. Linking to a QCL state means that when a PRS port number X and a DMRS port number Y are in a QCL state, the spatial information, Doppler shift, Doppler spread, and other transmission path characteristics of the transmission path of the PRS port number X are similar to the spatial information, Doppler shift, Doppler spread, and other transmission path characteristics of the transmission path of the DMRS port number Y. In other words, the beam direction used to transmit the PRS may be used for the DMRS. The spatial information setting may be applied within a resource set. In this case, the setting is applied to all resources within the resource set.

[0103] When multiple panels are used in the terminal device 20 for positioning, a resource set may be set for each panel. Incidentally, by installing multiple panels in the terminal device 20 and orienting each panel in a different direction, SRS can be transmitted from the terminal device 20 in all directions. In this case, spatial information is set for each panel. When the panels are oriented in different directions, spatial information needs to be set for each panel. Therefore, managing spatial information for each resource set can reduce the overhead required for setting. In such an operation, the number of panels on the UE side and the number of resource sets may be set equal. Furthermore, a panel identifier may be set for each resource set. By setting a panel identifier for each resource set, multiple resource sets can be associated with the same panel. Furthermore, the panel identifier may be associated with a resource within the resource set. In this case, the panel associated with a resource or beam becomes clear, and the operation of multiple panels can be managed within the resource set. FIG. 32 is a diagram illustrating an example of how panel numbers, resource sets, and resources are associated when multiple panels are used according to the seventh embodiment. In FIG. 32, five resources are configured in the base stations 10-1 and 10-2, and two resource sets are configured in each of the two panels of the terminal device 20. For example, a transmission beam and a reception beam are prepared within one resource set from the terminal device 20 toward the base station 10-1. In FIG. 32, two resources corresponding to the two beams from the terminal device 20 directed toward the base station 10-1 are prepared within one resource set. Furthermore, the transmission resource or reception resource is linked to resource number #2 and resource number #4 of the base station 10-1, respectively. That is, different panels of the terminal device 20 are associated with beams of the base station 10-1 directed in different directions. In the example of FIG. 32, control information associating a resource set identifier with two resource numbers of the base station 10-1 is generated by a server having a positioning function or the base station 10-1.Note that the association of the downlink reference signal and the uplink reference signal may be performed not only within the own cell but also with other cells. For example, the reference signal transmitted from the base station 10 of the cell in which the terminal device 20 exists may be associated with the reference signal transmitted from the base station 10 of the adjacent cell. By associating the direction of the beam transmitted from the base station 10 of the adjacent cell with the direction of the beam of the terminal device 20, the terminal device 20 can perform positioning using the adjacent cell base station. For this reason, a cell identifier, a TRP identifier, or a base station identifier may be added to the associated beam information to indicate that it is associated with another cell.

[0104] Furthermore, beams may be used for different purposes within the same resource set. For example, as mentioned above, SRS application methods are divided into UL codebook-based, UL non-codebook-based, UL beam management, and Antenna switching. Positioning resources, i.e., beams, may be defined within each applicable use case. In this case, the characteristics of the beam become characteristics suitable for positioning. For example, a positioning beam may only be set to be transmitted periodically.

[0105] Furthermore, even if multiple panels are not used in the uplink, when the UE transmits SRS to multiple different base stations 10, a resource set may be configured for each of the base stations 10. By transmitting SRS from the UE to different base stations 10, the base stations 10 can cooperate with each other and compare the times at which the SRS was received, thereby enabling estimation of the UE's location.

[0106] FIG. 33 is a diagram showing an example in which a UE according to the seventh embodiment sends an SRS to different base stations 10. In FIG. 33, the UE needs to transmit a positioning SRS to two base stations 10, and two resource sets are set, with resource set #1 corresponding to base station 10-1 and resource set #2 corresponding to base station 10-2. For example, a transmission beam or a reception beam directed from the terminal device 20 toward base station 10-1 is associated with resource number #4 of base station 10-1. By setting resource sets to different base stations 10 in this way, the terminal device 20 can reduce the overhead required for transmitting control information.

[0107] A port for transmitting the PRS is also set. The ports are assigned numbers, and up to one or two ports can be set. A port may be set for each resource. In this embodiment, a port refers to a logical antenna. In this embodiment, port setting will be described using an example of a PRS used for downlink. For example, using two ports can support up to two polarizations of a physical antenna. For example, the relationship between one port and the other port can be set. Furthermore, the relationship between a resource and a QCL can be set, and the same spatial information can be set. Types A, B, C, and D are set for the QCL, and Type A includes information related to Doppler shift, Doppler spread, mean delay, and delay dispersion. Type B includes information related to Doppler shift and Doppler spread. Type C includes information related to mean delay and Doppler shift. Type D includes spatial information related to reception. A QCL may be set for a PRS port or resource.

[0108] If the QCL state is the same between ports, it indicates that the propagation path characteristics are nearly identical, so the transmitting side can perform the same transmission processing. When two ports are configured for PRS, the same or different QCL states can be configured between the two ports. When the same QCL state is configured, similar transmission paths are propagated between the two ports. Also, different QCL states may be configured for the two ports configured for PRS. A PRS port may be associated with an SSB, DMRS, PTRS, TRS, or CSI-RS port. A port associated with the QCL state of a resource may be associated with an SSB, DMRS, PTRS, TRS, or CSI-RS port. A resource may be associated with an SSB, DMRS, PTRS, TRS, or CSI-RS port. Note that the port configuration for PRS applies to the PRS used in the downlink or the PRS configuration used in the uplink.

[0109] Embodiment 8 It is desirable that there be no interference from other signals within a period in which a reference signal used for positioning in the uplink is transmitted. Furthermore, transmitting multiple uplink reference signals for positioning allows the receiving side to average the received signals, thereby improving positioning accuracy. For this reason, the positioning SRS or uplink PRS may be allocated to a predetermined slot. Here, the SRS is used as an example. Only the SRS is allocated to the predetermined slot, and the SRS is not multiplexed with other reference signals, data signals, or control signals, even in the frequency domain. Here, a slot refers to a symbol consisting of 14 OFDM symbols or 14 DFT-s-OFDM symbols, but a slot may also refer to a set of symbols consisting of fewer than 14 symbols. By setting a slot in which only the positioning SRS is allocated, interference from other signals is reduced during positioning performed by the base station 10.

[0110] It should be noted that not all of the 14 symbols in a slot need to be used as positioning SRS for a UE. Unused symbols may be used as positioning SRS for another UE. Fig. 34 is a diagram showing an example of SRS multiplexed in the time domain according to the eighth embodiment. In Fig. 34, white symbols indicate unused symbols. The SRS symbols in the SRS resource for the second terminal device 20-2 are arranged at the 12th and 14th symbols, and the SRS resource for the SRS for the first terminal device 20-1 is arranged at the 11th and 13th symbols. In other words, the base station 10 transmits a reference signal for the first terminal device 20-1 and a reference signal for the second terminal device 20-2 at different symbol times.

[0111] FIG. 35 is a diagram showing an example of arrangement of SRSs multiplexed in the frequency domain according to the eighth embodiment. The positioning SRS may be frequency-multiplexed such that a plurality of SRSs corresponding to a plurality of terminal devices 20 are respectively multiplexed. In FIG. 35, the SRSs of the first terminal device 20-1 and the second terminal device 20-2 are multiplexed in the frequency domain at the 14th symbol. That is, in the example shown in FIG. 35, the base station 10 multiplexes a reference signal for the second terminal device 20-2 and a reference signal for the first terminal device 20-1 at the same symbol time. The position of the positioning SRS symbol may be represented as a bit array. For example, the position of the positioning SRS symbol of the first terminal device 20-1 in FIG. 34 can be represented as 00000000001010. Such information on the position of the positioning SRS symbol is notified to the first terminal device 20-1 by an upper layer or lower layer from a server having a positioning function or the base station 10. Furthermore, the terminal device 20 transmits the SRS based on the information on the position of the symbol of the positioning SRS.

[0112] FIG. 36 is a diagram showing an example of transmitting SRS resource information from a terminal device 20 to a base station 10 according to an eighth embodiment. In this embodiment, information indicating the location of an SRS resource is referred to as SRS resource information. The SRS resource indicates the location in the frequency domain and the time domain where the SRS is allocated. The SRS resource may be allocated across multiple OFDM or multiple DFT-s-OFDM symbol units, or may be allocated in units of one OFDM or one DFT-s-OFDM symbol. When transmitting SRS resource information from the terminal device 20 to the base station 10, the transmission timing needs to be determined before transmitting each piece of SRS resource information from the terminal device 20. By knowing the transmission interval of the SRS transmitted from the terminal device 20, the base station 10 can improve the SNR (Signal to Noise Ratio) of the received SRS signal by averaging processing, etc. Furthermore, when SRS is transmitted from multiple terminal devices 20, the multiple terminal devices 20 must set the SRS transmission interval and relative transmission timing in advance through scheduling and understand the transmission schedule so that the SRS transmitted from each terminal device 20 does not collide with each other. SRS resource information is transmitted, for example, periodically. Note that in FIG. 36, the interval between resources is indicated as T. The unit of T may be the number of symbols or time, or, for example, seconds. Furthermore, the allocation of resources in the time and frequency domain within a slot is unrelated to determining the timing to transmit SRS resource information; the interval between slots is important. At this time, the base station 10 transmits SRS resource information to multiple different beams. In this case, the base station 10 may perform beam sweeping or may transmit SRS with the beam direction already determined. When the base station 10 performs beam sweeping, the beam that transmits each SRS resource information is a candidate beam. If the beam direction is already determined and the SRS is to be transmitted, the base station 10 transmits positioning SRS.

[0113] FIG. 37 is a diagram showing an example of transmitting SRS resource information from a terminal device 20 according to the eighth embodiment to a plurality of base stations 10. In the example shown in FIG. 37, separate positioning SRS slots are used for base stations 10-1, 10-2, and 10-3. Note that while the examples of FIGS. 36 and 37 show examples in which SRS is transmitted at regular intervals, irregular intervals are also acceptable as long as each base station 10 can grasp the intervals. Note that in the example of FIG. 37, the interval between resources is indicated by T'. The unit of T' may be the number of symbols or time, for example, seconds.

[0114] When the upper layer parameter "usage" is "Positioning," it is desirable that the positioning SRS is not multiplexed with data or control channels within the slot. Since positioning slots are configured on a slot-by-slot basis, different usages may be time-multiplexed on a slot-by-slot basis. Multiplexing slots with different usages in this way allows for flexible configuration. The SRS used for positioning is also called PRS, uplink PRS, or uplink PRS.

[0115] Embodiment 9 3GPP proposes that the terminal device 20 derives its own location information. However, conventionally, the terminal device 20 only performs positioning in LTE, for example, deriving the difference in PRS reception time, and is not able to derive its own location information. To solve this problem, the base station 10 may notify the terminal device 20 of base station information, which is information related to the base station 10. The terminal device 20 derives its own location information using the base station information notified by the base station 10.

[0116] The following five pieces of base station information are examples. The first piece of base station information is an identifier of the base station 10. The second piece of base station information is information relating to the position of the base station 10. The third piece of base station information is information relating to the beam of the base station 10. The fourth piece of base station information is information relating to the synchronization of the base station 10. The fifth piece of base station information is information combining the first to fourth pieces of base station information. These pieces of information can be used as base station information for positioning by the terminal device 20. The terminal device 20 performs positioning using, for example, at least one of the first to fourth pieces of base station information. Furthermore, for example, the terminal device 20 performs positioning using information combining the first to fourth pieces of base station information.

[0117] The identifier of the base station 10 is, for example, a cell identifier. Alternatively, the identifier of the base station 10 may be a TRP identifier. The information regarding the position of the base station 10 may be, for example, position information derived by the base station 10 using a Global Navigation Satellite System (GNSS). The information regarding the beams of the base station 10 may include, for example, a beam identifier and information regarding the beam direction for each beam. The information regarding the beam direction for each beam may include information regarding the irradiation angle of the beam. The information regarding the beam direction may be information regarding the horizontal direction or the vertical direction.

[0118] The information related to the synchronization of the base station 10 may include, for example, base station information of surrounding base stations 10 with which time synchronization is achieved. Base stations 10 with the same DL frame timing as the time synchronization may be considered to be surrounding base stations 10 with which time synchronization is achieved. The base station information of surrounding base stations 10 may be a cell identifier. A plurality of groups of surrounding base stations 10 with which synchronization is achieved may be provided. An identifier may be provided for each group. The group identifier makes it possible to recognize which base station 10 is synchronized with which.

[0119] A method in which the base station 10 notifies the terminal device 20 of base station information will be described. The base station 10 broadcasts the base station information by including it in broadcast information. The base station 10 may transmit the broadcast information on the PBCH. Alternatively, the base station 10 may transmit the broadcast information on the PDSCH. Information indicating that the broadcast information is base station information for positioning by the terminal device 20 may be generated, and the broadcast information may be notified together with information indicating that the broadcast information is base station information. The base station 10 may generate an SIB for information indicating base station information for positioning by the terminal device 20. In this way, it is possible to acquire base station information not only in the RRC CONNECTED state, but also when the terminal device 20 is in the RRC IDLE state or the RRC INACTIVE state. The RRC CONNECTED state may also be referred to as the CONNECTED state. The RRC INACTIVE state may also be referred to as the INACTIVE state.

[0120] The base station 10 may notify the terminal device 20 of the base station information by RRC individual signaling. Information indicating that the base station information is for positioning by the terminal device 20 may be provided, and the base station information may be notified together with the information indicating that the base station information is for positioning. The base station information notified in the RRC CONNECTED state may be used in the RRC INACTIVE state. It is desirable that the terminal device 20 retains the base station information notified in the RRC CONNECTED state when transitioning to the INACTIVE state. In this way, it becomes possible to set base station information for each terminal device 20.

[0121] The base station 10 may notify the terminal device 20 of the base station information of the surrounding base stations 10. In this way, the terminal device 20 can obtain the base station information of the surrounding base stations 10 from the base station 10. Here, the base stations 10 surrounding the base station 10 are referred to as surrounding base stations. The base station information of the first base station may be included in the base station information of the surrounding base stations transmitted by a first base station, which is one of the base stations 10. In this way, the terminal device 20 can obtain the base station information of the surrounding base stations of the first base station from the first base station. For example, the terminal device 20 acquires the base station information of the surrounding base stations from the first base station. The terminal device 20 receives information indicating that the base station information is for positioning by the terminal device 20 together with the base station information of the surrounding base stations, and performs positioning using the acquired base station information of the surrounding base stations. The positioning method may be performed using the above-mentioned method or a conventional method as appropriate, and is not limited to this method. The terminal device 20 derives its own location information using the base station information of each surrounding base station that has performed positioning. For example, it is preferable to derive the position information of the terminal device 20 itself using the position information of a plurality of base stations 10, beam irradiation angle information, and the like.

[0122] The terminal device 20 may perform positioning using information indicating synchronized base stations from the received information on synchronization for each base station 10. For example, there may be unsynchronized base stations 10 located in the vicinity. If positioning and location information are performed using base station information transmitted from unsynchronized base stations 10, the difference in reception timing between the base stations 10 cannot be accurately derived, and accurate location information cannot be obtained. Therefore, the terminal device 20 can perform positioning and derive location information using base station information from synchronized neighboring base stations, thereby deriving accurate location information of the terminal device 20 itself.

[0123] As another method, the base station 10 may notify the terminal device 20 of its own base station information. In this way, it is possible to reduce the amount of information that the first base station notifies the terminal device 20. For example, the base station 10 broadcasts the base station information of its own base station by including it in broadcast information. The terminal device 20 acquires the base station information by receiving the broadcast information of the base station 10. For example, the terminal device 20 may perform positioning using the base station information of the base station 10 that has received the base station information for positioning. For example, the terminal device 20 may perform positioning using the base station information of the first base station from which the base station information has been acquired and the base station information of surrounding base stations. The terminal device 20 derives its own position information using the base station information of each base station 10 that has performed positioning. For example, the terminal device 20 may derive its own position information using the position information and beam irradiation angle information of multiple base stations 10.

[0124] If the base station information of the first base station includes information about synchronization, the terminal device 20 may perform positioning using the base station information of neighboring base stations with which it is synchronized. By performing positioning and deriving location information using the base station information of neighboring base stations with which it is synchronized, it becomes possible to derive accurate location information of the terminal device 20 itself.

[0125] When the received power of the base station 10 falls below a threshold, the terminal device 20 in the IDLE state or the INACTIVE state searches for neighboring base stations. The terminal device 20 searches for neighboring base stations as part of a cell reselection process. When searching for neighboring base stations, the terminal device 20 may perform positioning by itself. When searching for neighboring base stations, the terminal device 20 may receive broadcast information from the neighboring base stations and derive its own position information. In this way, it becomes possible to derive the position information of the terminal device 20 itself. However, if the positioning by the terminal device 20 is performed only when searching for neighboring base stations in this way, problems may arise. This is because, depending on the service, timely position information of the terminal device 20 may be required. A method for solving such problems will be described.

[0126] The base station 10 notifies the terminal device 20 of information instructing the terminal device 20 to perform positioning. For example, the base station 10 may notify the terminal device 20 of the information instructing the terminal device 20 to perform positioning by using paging. The base station 10 may notify the terminal device 20 in a CONNECTED state, an IDLE state, or an INACTIVE state. In this way, for example, the base station 10 can cause the terminal device 20 to perform positioning by the terminal device 20 at a timing suitable for the service.

[0127] The paging information may include information on an SIB containing base station information. According to the information included in the paging information, the terminal device 20 can receive the SIB containing the base station information and acquire the base station information. The terminal device 20 uses the base station information to derive its own location information.

[0128] As another method of notifying the information instructing the terminal device 20 to perform positioning, for example, the base station 10 may notify by RRC individual signaling. The base station 10 may notify information about the base station 10 in association with the information instructing the terminal device 20 to perform positioning. Alternatively, the base station 10 may notify the instruction to perform positioning by the terminal device 20 by MAC signaling. The base station 10 may notify by associating the information with information about the base station 10 notified by RRC signaling. Alternatively, the base station 10 may notify by using PDCCH. The base station 10 may notify by associating the information instructing the terminal device 20 to perform positioning with information about the base station 10 notified by RRC signaling. In this way, it is possible to cause the terminal device 20 to perform positioning by the terminal device 20 early.

[0129] The base station 10 may cause the terminal device 20 to periodically perform positioning. For example, the base station 10 notifies the terminal device 20 of periodic information, which is information indicating the period of positioning by the terminal device 20. Alternatively, the periodic information may be statically determined in advance by a standard or the like. Alternatively, the periodic information may be set from an upper layer of the terminal device 20 to a lower layer. For example, the periodic information may be set from the application layer to a NAS (Non Access Stratum) or AS (Access Stratum) layer.

[0130] The base station 10 may appropriately apply a method for notifying the base station information of the base station 10 to the terminal device 20 of periodic information related to positioning by the terminal device 20. Alternatively, the base station 10 may notify the periodic information related to positioning by including it in the base station information. As another method, the base station 10 may appropriately apply a method for notifying information instructing the terminal device 20 to perform positioning by the terminal device 20 to notify the terminal device 20 of periodic information related to positioning by the terminal device 20. In this way, the terminal device 20 can periodically perform positioning by the terminal device 20.

[0131] The terminal device 20 may notify the base station 10 of the positioning result by the terminal device 20. The terminal device 20 may include its own location information derived by the terminal device 20 as the positioning result. The terminal device 20 may use RRC signaling to notify the result. A method for the terminal device 20 in the IDLE state or INACTIVE state to transmit the positioning result by the terminal device 20 to the base station 10 is to first transition to the CONNECTED state and then notify the base station 10. By transitioning to the CONNECTED state, the terminal device 20 becomes able to notify the base station 10 by RRC signaling.

[0132] As another method for the terminal device 20 in the IDLE state or the INACTIVE state to transmit the positioning result by the terminal device 20 to the base station 10, the terminal device 20 may notify by RA (Random Access) processing. Alternatively, the terminal device 20 may notify as data on the control plane. For example, the terminal device 20 notifies by including the positioning result in an RRC connection request. The terminal device 20 may notify by including information that the RRC connection request is a notification of the positioning result. The base station 10 that acquires the positioning result from the terminal device 20 may stop the RRC connection processing. In this way, the terminal device 20 can notify the base station 10 of the positioning result by the terminal device 20 without establishing an RRC connection. The terminal device 20 can notify the base station 10 of the positioning result of the terminal device 20 early.

[0133] The base station 10 configures one or more cells. For example, the information about the beam may be information about the beam for each cell. The base station 10 may be a TRP. For example, the information about the beam may be information about the beam for each TRP.

[0134] In this embodiment, the base station 10 notifies the terminal device 20 of information about the beam, but if the LMF is provided in another node, the node in which the LMF is provided may notify the terminal device 20. In this case, the base station information, etc. may be added and notified by the base station 10. Alternatively, the base station 10 may notify the node in which the LMF is provided. In this way, it becomes possible to have the terminal device 20 perform positioning from the LMF. The LMF may be provided in the base station 10, and in this case, the above-mentioned method may be applied.

[0135] Embodiment 10 Positioning by the terminal device 20 may be performed in multiple stages. For example, a first stage of positioning may be performed by the terminal device 20 in an RRC_IDLE or RRC_INACTIVE state, and a second stage of positioning may be performed by the terminal device 20 in an RRC_CONNECTED state. As another example, the first stage of positioning and the second stage of positioning may be performed by the terminal device 20 in an RRC_IDLE or RRC_INACTIVE state. In each of the multiple stages of positioning performed by the terminal device 20, a different base station 10 may be used for positioning, a different positioning method may be used, a different signal may be used for positioning, or a different entity may determine the base station 10 to be used for positioning.

[0136] For example, in the first stage of positioning, positioning using SSB may be performed for a terminal device 20 in the RRC_INACTIVE or RRC_IDLE state. The terminal device 20 in the RRC_INACTIVE or RRC_IDLE state may determine by itself the base station 10 to be used for positioning. For example, the terminal device 20 may determine the base station 10 to be used for positioning as the base station 10 that transmits SSB that can be received by the terminal device itself.

[0137] The LMF may notify the terminal device 20 in the RRC_INACTIVE or RRC_IDLE state that positioning using SSB will be performed. The notification that positioning using SSB will be performed may be made, for example, via the base station 10. The notification that positioning using SSB will be performed may be made, for example, in the RRC_CONNECTED state before the terminal device 20 transitions to the RRC_INACTIVE or RRC_IDLE state.

[0138] The LMF may notify the terminal device 20 in the RRC_INACTIVE or RRC_IDLE state that positioning using SSB will be performed. This notification may be made via the base station 10, for example. Eight pieces of information can be included in this notification. The first piece of information is information related to the RRC state in which the positioning signal is received. The second piece of information is information related to whether or not the position of the terminal device 20 needs to be derived. The third piece of information is information related to the system used for positioning. The fourth piece of information is information related to the positioning signal. The fifth piece of information is information related to the number of times the positioning signal is received. The sixth piece of information is information related to the period in which the positioning signal is received. The seventh piece of information is information related to the notification conditions to the base station 10. The eighth piece of information is information obtained by combining the first to seventh pieces of information. The terminal device 20 derives the position of the terminal device 20, for example, by using at least one of the first to seventh pieces of information included in the notification. Furthermore, the terminal device 20 derives the position of the terminal device 20, for example, by using information obtained by combining the first to seventh pieces of information.

[0139] The information included in the first information may be, for example, RRC_INACTIVE, RRC_IDLE, or a combination of two or more of the above. The terminal device 20 may receive a positioning signal when it transitions to the RRC state included in the first information. This makes it possible to receive a positioning signal when, for example, the RRC state of the terminal device 20 changes.

[0140] The information included in the second information may be, for example, information indicating that the position of the terminal device 20 is to be derived. When the second information includes information indicating that the position of the terminal device 20 is to be derived, the terminal device 20 may derive the position of the terminal device 20. For example, the reception result of a positioning signal from the base station 10 used for positioning may be used to derive the position of the terminal device 20. The terminal device 20 may notify the LMF of the derivation result. The notification of the derivation result may be made to the base station 10. The notification of the derivation result by the terminal device 20 may be made when the terminal device 20 is in an RRC_CONNECTED state.

[0141] Another example of the information included in the second information may be information indicating that position derivation is not performed for the terminal device 20. When the information included in the second information includes information indicating that position derivation is not performed for the terminal device 20, the terminal device 20 may report a reception result of the positioning signal to the base station 10. The notification of the report of the reception result of the positioning signal by the terminal device 20 may be performed when the terminal device 20 is in the RRC_CONNECTED state.

[0142] The information included in the third information may be, for example, a 5G system, an LTE system, a GNSS, Wifi (registered trademark), Bluetooth (registered trademark), or another system. The terminal device 20 may perform positioning or may receive a positioning signal using the third information. This may improve the flexibility of the positioning of the terminal device 20, for example.

[0143] The information included in the fourth information may be, for example, SSB, CSI-RS, DMRS, or a signal used in another system.

[0144] The information included in the fifth information may be, for example, one time or multiple times. The terminal device 20 may perform a series of operations for receiving positioning signals the number of times included in the fifth information. For example, by performing a series of operations for receiving positioning signals multiple times, the terminal device 20 can improve the accuracy of positioning in the RRC_INACTIVE or RRC_IDLE state.

[0145] The information included in the sixth information may be specified, for example, in millisecond units, in radio frame units, or using a parameter associated with a predetermined time. The terminal device 20 may periodically receive positioning signals using the information. This makes it possible to capture the position of the terminal device 20 in the communication system even if the position of the terminal device 20 changes.

[0146] The information included in the seventh information may be, for example, movement to a different RAN Notification Area (RNA) or a different Tracking Area (TA), or may be given as a condition related to RSSI. The condition related to RSSI may be, for example, that the RSSI of the terminal device 20 is equal to or exceeds a predetermined value, or may be equal to or falls below a predetermined value. As another example, the condition may be given using the received power from the base station 10 to which the terminal device 20 was connected in the RRC_CONNECTED state and the received power from another base station 10. The terminal device 20 may start receiving positioning signals using the information. This makes it possible, for example, in a communication system, to quickly capture changes in the position of the terminal device 20, and as a result, it is possible to improve the stability of the communication system, for example, when returning to RRC_CONNECTED.

[0147] As another example of positioning in the IDLE or INACTIVE state, CSI-RS may be used. The terminal device 20 may receive CSI-RS from multiple base stations 10, multiple panels, or TRPs. The terminal device 20 may retain information related to the reception time of the CSI-RS. The information related to the reception time of the CSI-RS may be, for example, the difference between the reception times of the multiple CSI-RSs. By using CSI-RS, for example, positioning using a narrow beam becomes possible, thereby improving the positioning accuracy. The base station 10 may notify the terminal device 20 of settings related to CSI-RS. The notification from the base station 10 to the terminal device 20 may be performed when the terminal device 20 is in an RRC_CONNECTED state. The settings related to CSI-RS may include, for example, information related to the base station 10, DU (Distributed Unit), TRP, or panel that transmits the CSI-RS, or information related to the frequency, time, or code resource on which the CSI-RS is transmitted. Examples of the information related to the panel include the identifier of the base station 10, the identifier of the DU, the identifier of the TRP, the identifier of the panel, and information related to the position.

[0148] The terminal device 20 may use information about the location to derive the location of the terminal device itself. This eliminates, for example, the need for the terminal device 20 to transmit measurement results, such as the difference in PRS reception times, to the base station 10. As a result, it is possible to reduce the amount of signaling between the base station 10 and the terminal device 20 and to eliminate the need to resume communication between the terminal device 20 and the base station 10. This enables rapid positioning in the communication system. As another example, the base station 10 may derive the location of the terminal device 20 using information about the CSI-RS reception time. The terminal device 20 may notify the base station 10 of information about the CSI-RS reception time. This notification may be included, for example, in a measurement result report from the terminal device 20 to the base station 10, or may be included in different signaling. The base station 10 may derive the location of the terminal device 20 using information about the CSI-RS reception time. This, for example, makes it possible to reduce the load on the terminal device 20 due to location derivation. Also, as with SSB, the first and second embodiments may be used in combination. In the first embodiment, angle information is obtained from a selected beam and positioning is performed using distance information. In the second embodiment, RSTD is calculated from the reception times of reference signals transmitted from multiple transmitters and positioning is performed. The average of positions obtained by both methods may be calculated. Furthermore, when positioning is performed using multiple base stations 10, some base stations 10 may use the method described in the first embodiment and the other base stations 10 may use the method described in the second embodiment.

[0149] In the second stage, positioning using CSI-RS may be performed. The LMF may determine the base station 10 to be used in the second stage of positioning using the positioning result of the terminal device 20 obtained in the first stage of positioning. The base station 10 may transmit the CSI-RS to the terminal device 20. The terminal device 20 may receive the CSI-RS. The terminal device 20 may notify the base station 10 of the reception result of the CSI-RS. The base station 10 may use the reception result to determine the position of the terminal device 20. This makes it possible to reduce the amount of signaling in the communication system while improving the positioning accuracy, for example.

[0150] According to the tenth embodiment, it is possible to improve the accuracy of positioning and the flexibility of positioning, and also to improve the efficiency of the communication system.

[0151] The configurations shown in the above embodiments are examples of the content of the present invention, and may be combined with other known technologies, and some of the configurations may be omitted or modified within the scope of the gist of the present invention. [Explanation of symbols]

[0152] 1 to 4: beams, 10, 10-1, 10-2: base station, 20: terminal device, 20-1: first terminal device, 20-2: second terminal device, 101: control unit, 102: transmission signal generation unit, 103: transmission processing unit, 104: reception processing unit, 105: reception signal decoding unit, 106: positioning processing unit, 200: server, 400: control circuit, 400a: processor, 400b: memory.

Claims

1. a communication unit for receiving higher layer parameters related to a positioning reference signal; a control unit that performs positioning using the positioning reference signal received based on the upper layer parameters; Equipped with the upper layer parameter is hierarchical information including a resource set parameter having a plurality of resource parameters; In adjacent orthogonal frequency division multiplexing symbols, the positioning reference signals are arranged at intervals of two or more resource elements; the positioning reference signal is located in an active bandwidth portion; The control unit performs measurement of the positioning reference signal in a measurement gap. User equipment.

2. A communication unit that receives higher layer parameters related to a positioning reference signal; a control unit that performs positioning using the positioning reference signal received based on the upper layer parameters; Equipped with the upper layer parameter is hierarchical information including a resource set parameter having a plurality of resource parameters; In adjacent orthogonal frequency division multiplexing symbols, the positioning reference signals are arranged at intervals of two or more resource elements; The communication unit receives the positioning reference signals transmitted from a plurality of transmitting and receiving points using a common cyclic prefix length and a common subcarrier spacing. User equipment.

3. The positioning reference signals are arranged so that they are spaced apart by n resource elements in the frequency domain when spaced apart by n symbols in the time domain.

3. A user device according to claim 1 or 2.

4. The communication unit receives the upper layer parameters including information about the density of the positioning reference signal.

3. A user device according to claim 1 or 2.

5. The communication unit receives the positioning reference signal transmitted using only symbols set for downlink.

3. A user device according to claim 1 or 2.

6. In the upper layer parameters, muting is set in units of the resource set parameters.

3. A user device according to claim 1 or 2.

7. a control unit that configures higher layer parameters related to a positioning reference signal used for positioning in a user equipment; a communication unit that transmits the upper layer parameters to the user equipment; the upper layer parameter is hierarchical information including a resource set parameter having a plurality of resource parameters; In adjacent orthogonal frequency division multiplexing symbols, the positioning reference signals are arranged at intervals of two or more resource elements; the positioning reference signal is located in an active bandwidth portion; Measurement of the positioning reference signal is performed in the measurement gap. Base station.

8. A control unit that configures upper layer parameters related to a positioning reference signal used for positioning in a user equipment; a communication unit that transmits the upper layer parameters to the user equipment; the upper layer parameter is hierarchical information including a resource set parameter having a plurality of resource parameters; In adjacent orthogonal frequency division multiplexing symbols, the positioning reference signals are arranged at intervals of two or more resource elements; The communication unit transmits the positioning reference signal using a cyclic prefix length and a subcarrier interval that are common to the positioning reference signals transmitted from a plurality of transmission and reception points. Base station.

9. A communication system comprising a user equipment and a base station, The base station transmits higher layer parameters related to a positioning reference signal to the user equipment; the user equipment performs positioning using the positioning reference signal received based on the higher layer parameter; the upper layer parameter is hierarchical information including a resource set parameter having a plurality of resource parameters; In adjacent orthogonal frequency division multiplexing symbols, the positioning reference signals are arranged at intervals of two or more resource elements; the positioning reference signal is located in an active bandwidth portion; The user equipment performs measurement of the positioning reference signal in a measurement gap. Communication system.

10. A communication system comprising a user equipment and a base station, The base station transmits higher layer parameters related to a positioning reference signal to the user equipment; the user equipment performs positioning using the positioning reference signal received based on the higher layer parameter; the upper layer parameter is hierarchical information including a resource set parameter having a plurality of resource parameters; In adjacent orthogonal frequency division multiplexing symbols, the positioning reference signals are arranged at intervals of two or more resource elements; The user equipment receives the positioning reference signals transmitted from a plurality of transmitting and receiving points using a common cyclic prefix length and a common subcarrier spacing. Communication system.

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