Terminal device, base station device, and wireless communication system

Abstract

The present invention is provided with: a measurement unit that measures a first signal transmitted from a second base station device in response to reception of instruction information relating to the first signal from a first base station device; and a transmission unit that transmits the measurement result relating to the first signal to the first base station device.

Description

Terminal device, base station device, and wireless communication system

[0001] The present disclosure relates to a terminal device, a base station device, and a wireless communication system.

[0002] In the current network, the traffic of mobile terminals (smartphones and feature phones) occupies most of the network resources and is expected to continue to grow in the future. Also, in addition to the traffic used by mobile terminals, for example, the deployment of IoT (Internet of Things) services (such as traffic systems, monitoring systems for smart meters or devices, etc.) is underway. Therefore, such a network is required to support services with diverse requirement conditions.

[0003] In order to support such diverse services, in the communication standards of the fifth-generation mobile communication (5G or NR (New Radio)) (for example, Non-Patent Documents 1 to 14), standards assuming support for many use cases classified into, for example, eMBB (Enhanced Mobile BroadBand), Massive MTC (Machine Type Communications), and URLLC (Ultra-Reliable and Low Latency Communications) have been formulated.

[0004] And in the Third Generation Partnership Project (3GPP: 3rd Generation Partnership Project (registered trademark)), which is an international standardization project, even currently, extended technologies of the above communication standards are continuously being studied and standardized.

[0005] For example, the 3GPP working group is considering introducing CSI-RS (Channel State Information Reference Signal) as a reference signal for beam measurement of Candidate Cells in LTM (L1 / L2 Triggered Mobility). LTM is a technology that performs Cell Switching (Handover) between Cells at Layer 1 and Layer 2. Candidate Cells are Cells that are the target of LTM and are candidates for Cell Switching. Hereafter, Cells to which a UE is connected will also be called Serving Cells. Furthermore, the Candidate Cell targeted by Cell Switch will also be referred to as the Target Cell.

[0006] 3GPP TS 37.324 V18.0.03GPP TS 37.340 V18.2.03GPP TS 38.201 V18.0.03GPP TS 38.202 V18.3.03GPP TS 38.211 V18.3.03GPP TS 38.212 V18.3.03GPP TS 38.213 V18.3.03GPP TS 38.214 V18.3.03GPP TS 38.215 V18.3.03GPP TS 38.300 V18.2.03GPP TS 38.321 V18.2.03GPP TS 38.322 V18.1.03GPP TS 38.323 V18.2.03GPP TS 38.331 V18.2.0

[0007] However, the method by which the Candidate Cell transmits CSI-RS has not yet been determined. Specifically, for example, the method for synchronizing the timing of the Candidate Cell's transmission of CSI-RS with the timing of the terminal device's reception (measurement) of CSI-RS has not yet been determined.

[0008] Therefore, the Disclosure provides a terminal device, a base station device, and a wireless communication system that enable CSI-RS transmission by Candidate Cell.

[0009] The system includes a measuring unit that measures the first signal transmitted from the second base station device in response to receiving instruction information relating to the first signal transmitted from the first base station device, and a transmitting unit that transmits the measurement results for the first signal to the first base station device.

[0010] One disclosure enables CSI-RS transmission via Candidate Cell.

[0011] Figure 1 shows an example configuration of the wireless communication system 10. Figure 2 shows an example configuration of the terminal device 100. Figure 3 shows an example configuration of the base station device 200. Figure 4 shows an example sequence in the first embodiment. Figure 5 shows an example sequence in the second embodiment. Figure 6 shows an example sequence in the third embodiment. Figure 7 shows an example sequence in the fourth embodiment. Figure 8 shows an example sequence in the fifth embodiment. Figure 9 shows an example sequence in the sixth embodiment.

[0012] Embodiments of this disclosure will be described below with reference to the drawings. However, this description should not be interpreted as limiting, and will not limit the subject matter described in the claims. Furthermore, various changes, substitutions, and modifications can be made without departing from the spirit and scope of this disclosure. Different embodiments can also be combined as appropriate.

[0013] [First Embodiment] (Regarding the Wireless Communication System 10) Figure 1 is a diagram showing an example of the configuration of the wireless communication system 10. The wireless communication system 10 includes, for example, a terminal device 100, a base station device 200a, and a base station device 200b. Hereinafter, the base station device 200a and the base station device 200b will be collectively referred to simply as the base station device 200. Furthermore, the following description will assume that the base station device 200a is a base station device 200 corresponding to a Serving Cell. Furthermore, the following description will assume that the base station device 200b is a base station device 200 corresponding to a Candidate Cell. In addition, the following description will assume that the wireless communication system 10 has one base station device 200b, but the wireless communication system 10 may have, for example, multiple base station devices 200b.

[0014] The terminal device 100 is a communication device that wirelessly connects to the base station device 200 and transmits and receives data, and is, for example, a smartphone or a tablet terminal.

[0015] The base station device 200 is a device that wirelessly connects with the terminal device 100 and transmits and receives data, and is, for example, an eNodeB or a gNodeB. The base station device 200 supports various communication generations (for example, 4G, 5G, or Beyond 5G). The base station device 200 may consist of a single unit or multiple units such as a CU (Central Unit) or a DU (Distributed Unit).

[0016] (Example of configuration of terminal device 100) Figure 2 shows an example of the configuration of terminal device 100. Terminal device 100 has a CPU (Central Processing Unit) 110, storage 120, memory 130 and wireless communication circuit 150.

[0017] Storage 120 is an auxiliary storage device that stores programs and data, and is a flash memory, HDD (Hard Disk Drive), or SSD (Solid State Drive), etc. Storage 120 stores the terminal communication program 121 and the signal measurement program 122.

[0018] Memory 130 is the area where programs stored in storage 120 are loaded. Memory 130 may also be used as an area where programs store data.

[0019] The wireless communication circuit 150 is a circuit that communicates wirelessly with the base station device 200. The wireless communication circuit 150 has an antenna 151. The antenna 151 includes, for example, a directional antenna that can control the direction of transmission and reception of radio waves. The wireless communication circuit 150 can also change the transmission power.

[0020] The CPU 110 is a processor that builds each part and then performs each process by loading programs stored in the storage 120 into the memory 130 and executing them.

[0021] The CPU 110 constructs the receiving and transmitting units by executing the terminal communication program 121 and performs terminal communication processing. Terminal communication processing involves establishing a wireless connection with the base station device 200 and performing wireless communication.

[0022] The CPU 110 constructs a signal measurement unit (hereinafter also simply referred to as the measurement unit) by executing the signal measurement program 122 and performs signal measurement processing. The signal measurement processing is the process of measuring the CSI-RS transmitted from the base station device 200b.

[0023] (Example of the configuration of the base station device 200) Figure 3 shows an example of the configuration of the base station device 200. The base station device 200 has a CPU 210, storage 220, memory 230 and wireless communication circuit 250.

[0024] Storage 220 is an auxiliary storage device that stores programs and data, and is a flash memory, HDD, or SSD, etc. Storage 220 stores the base station communication program 221 and the LTM control program 222.

[0025] Memory 230 is the area where programs stored in storage 220 are loaded. Memory 230 may also be used as an area where programs store data.

[0026] The wireless communication circuit 250 is a device that communicates wirelessly with the terminal device 100. The wireless communication circuit 250 has an antenna 251. The antenna 251 includes, for example, a directional antenna that can control the direction of transmission and reception of radio waves.

[0027] The CPU 210 is a processor that builds each part and then performs each process by loading programs stored in the storage 220 into the memory 230 and executing them.

[0028] The CPU 210 constructs the receiving and transmitting units and performs base station communication processing by executing the base station communication program 221. Base station communication processing is the process of wirelessly communicating with the terminal device 100. Specifically, in base station communication processing, the base station device 200 establishes a wireless connection with the terminal device 100, transmits data to the terminal device 100, and receives data from the terminal device 100.

[0029] The CPU 210 constructs an LTM control unit (hereinafter also simply referred to as the control unit) by executing the LTM control program 222 and performs LTM control processing. LTM control processing is the process of controlling the LTM in relation to the base station equipment 200b.

[0030] [First Embodiment] Next, a first embodiment will be described. Figure 4 is a diagram showing an example of the sequence in the first embodiment. The following description will focus on the case where the base station device 200b is a base station device 200 corresponding to a Candidate Cell and also a base station device 200 corresponding to a Target Cell.

[0031] The base station device 200a transmits, for example, the RRC Configuration for base station device 200b to the terminal device 100 (S11).

[0032] Furthermore, the base station device 200a transmits information (hereinafter also referred to as instruction information or CSI-RS related information) to the base station device 200b, for example (S12). CSI-RS for CSI is a CSI-RS used, for example, for measuring channel information related to scheduling such as RI, PMI, CQI, and LI.

[0033] Specifically, base station device 200a transmits, for example, information about Antenna Port used for CSI-RS for CSI transmission. Base station device 200a also transmits, for example, information about transmission resources used for CSI-RS for CSI transmission. Furthermore, base station device 200a transmits, for example, information about the transmission timing for CSI-RS for CSI. Note that base station device 200 may also transmit, for example, information about beams used for CSI-RS for CSI transmission as information about transmission resources used for CSI-RS for CSI transmission. Additionally, base station device 200a may transmit a CSI-RS resource set and / or CSI-RS resource index used for CSI-RS transmission to base station device 200b.

[0034] A single CSI-RS resource set may contain one or more CSI-RS resources. Each of the CSI-RS resources included in the CSI-RS resource set may be assigned an index. For example, the base station device 200 may notify the terminal device 100 of the index of a CSI-RS resource and instruct it to transmit CSI-RS based on that CSI-RS resource. The CSI-RS resource may include information about the resource to which the CSI-RS is mapped, parameters related to the transmission power, a scrambling index, a period and offset, an antenna port used for CSI-RS transmission, and the like.

[0035] A CSI-RS resource may be associated with a CSI report that reports the results of channel measurements performed using the CSI-RS resource. The CSI report may be composed of a higher-level parameter CSI-ReportConfig. CSI-ReportConfig may include parameters necessary for sending the CSI report. For example, it may include the period of the CSI report, the resource to which the CSI report is mapped, and the type of measurement results included in the CSI report.

[0036] The base station device 200b then transmits, for example, an SSB (SS / PBCH Block) or a CSI-RS different from CSI (hereinafter also referred to as the second signal or CSI-RS for BM (Beam Management)) to the terminal device 100 (S13). The CSI-RS for BM is, for example, a CSI-RS used for measuring RSRP (Reference Signal Received Power) used in the implementation of Cell Switch or SINR (Signal to Interference plus Noise Ratio). Furthermore, CSI-RS for BM is a CSI-RS used, for example, to determine the conditions of the Event-Trigger for initiating the transmission (reporting) of measurement results by the terminal device 100.

[0037] Furthermore, the base station device 200b transmits, for example, CSI-RS for CSI to the terminal device 100 (S14).

[0038] Subsequently, the terminal device 100 measures (receives) the SSB or CSI-RS for BM transmitted from the base station device 200b in, for example, S13, and transmits the measurement result to the base station device 200a (S15).

[0039] Furthermore, the terminal device 100 measures (receives) the CSI-RS for CSI transmitted from the base station device 200b in S14, and transmits the measurement result to the base station device 200a (S16).

[0040] That is, the terminal device 100 performs, for example, the transmission of CSI-RS for CSI at a timing associated with CSI-RS for BM.

[0041] Specifically, the terminal device 100 receives CSI-RS for CSI, for example, after a certain time (N slots or N frames) has elapsed since the reception of SSB or CSI-RS for BM. Here, N may be an integer of 0 or more.

[0042] Further, the terminal device 100 transmits a measurement device to the base station device 200a by using a transmission resource associated with the transmission resource used for the transmission of CSI-RS for CSI in S14.

[0043] Note that the information indicating the transmission timing of CSI-RS for CSI (for example, the certain time N) may be included in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S11. Also, the information indicating the transmission timing of CSI-RS for CSI may be described in a specification, for example.

[0044] Also, the information indicating the transmission resource used for the transmission of CSI-RS for CSI may be included in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S11.

[0045] Further, the terminal device 100 may not perform S16, for example, when the measurement result of the SSB or CSI-RS for BM transmitted from the base station device 200b in S13 is less than a threshold value.

[0046] Thereafter, the base station device 200a transfers the measurement result of CSI-RS for CSI transmitted from the terminal device 100 in S16 to the base station device 200b (S17).

[0047] Then, the base station device 200a determines whether or not to perform Cell Switch based on, for example, the measurement results of the SSB or CSI-RS for BM transmitted from the terminal device 100 in S15. When it is determined that it is necessary to perform Cell Switch, an LTM Cell Switch Command MAC CE (hereinafter, also simply referred to as a Cell Switch command) is transmitted to the terminal device 100 (S18).

[0048] As a result, the wireless communication system 10 in the present embodiment can synchronize, for example, the timing at which the base station device 200b transmits CSI-RS for CSI and the timing at which the terminal device 100 measures (receives) CSI-RS for CSI. Specifically, the wireless communication system 10, for example, even when the base station device 200a instructs the terminal device 100 to measure and report (report) CSI-RS for CSI and the base station device 200b transmits CSI-RS for CSI to the terminal device 100, can synchronize the timing at which the base station device 200b transmits CSI-RS for CSI and the timing at which the terminal device 100 measures (receives) CSI-RS for CSI. Also, the wireless communication system 10, for example, even when the base station device 200a and the base station device 200b are composed of different DUs or CUs, can synchronize the timing at which the base station device 200b transmits CSI-RS for CSI and the timing at which the terminal device 100 measures (receives) CSI-RS for CSI.

[0049] Also, the wireless communication system 10 in the present embodiment can, for example, share the Measurement Gap required for Inter-Frequency measurement.

[0050] In the wireless communication system 10 of this embodiment, the transmission timing and whether or not Candidate Cell TCI (Transmission Configuration Indicator) States Activation / Deactivation MAC CE (hereinafter also simply referred to as TCI State Activation) or PRACH (Physical Random Access Channel) are performed do not affect the processes in this embodiment.

[0051] [Second Embodiment] Next, a second embodiment will be described. Figure 5 is a diagram showing an example of a sequence in the second embodiment.

[0052] The base station device 200a transmits, for example, the RRC Configuration for base station device 200b to the terminal device 100 (S21).

[0053] Specifically, base station device 200a transmits an RRC Configuration to terminal device 100, which includes information about the timing and frequency of RACH (Random Access Channel) and Preamble resources between it and base station device 200b.

[0054] Furthermore, the base station device 200b transmits, for example, SSB or CSI-RS for BM to the terminal device 100 (S22).

[0055] Then, the terminal device 100 measures (receives) the SSB or CSI-RS for BM transmitted from the base station device 200b in S22, and transmits the measurement result to the base station device 200a (S23).

[0056] Subsequently, the base station device 200a transmits a PDCCH (Physical Downlink Control Channel) Order to the terminal device 100, for example, instructing it to transmit a PRACH (hereinafter also called the third signal) to the base station device 200b (S24).

[0057] Specifically, if, for example, in S23, the base station device 200a receives measurement results for multiple base station devices 200b from the terminal device 100, it selects the base station device 200b with the best measurement result (e.g., RSRP) and sends a PDCCH Order instructing the selected base station device 200b to send a PRACH.

[0058] Furthermore, the base station device 200a transmits, for example, information (CSI-RS related information) to the base station device 200b, including information about the transmission timing of CSI-RS for CSI and information about transmission resources (S25).

[0059] Specifically, base station device 200a transmits information about transmission resources, such as information about Antenna Port used for CSI-RS for CSI transmission and information about Resource Mapping. Base station device 200a also transmits information about the transmission timing for CSI-RS for CSI. Furthermore, base station device 200a may transmit the CSI-RS resource set and / or CSI-RS resource index used for CSI-RS transmission to base station device 200b.

[0060] A single CSI-RS resource set may contain one or more CSI-RS resources. Each of the CSI-RS resources included in the CSI-RS resource set may be assigned an index. For example, the base station device 200 may notify the terminal device 100 of the index of a CSI-RS resource and instruct it to transmit CSI-RS based on that CSI-RS resource. The CSI-RS resource may include information about the resource to which the CSI-RS is mapped, parameters related to the transmission power, a scrambling index, a period and offset, an antenna port used for CSI-RS transmission, and the like.

[0061] A CSI-RS resource may be associated with a CSI report that reports the results of channel measurements performed using the CSI-RS resource. The CSI report may be composed of a higher-level parameter CSI-ReportConfig. CSI-ReportConfig may include parameters necessary for sending the CSI report. For example, it may include the period of the CSI report, the resource to which the CSI report is mapped, and the type of measurement results included in the CSI report.

[0062] Then, the terminal device 100 transmits a PRAC to the base station device 200b, which is instructed by the PRAC Order transmitted from the base station device 200a in S24 (S26).

[0063] The terminal device 100 may transmit PRAC by using a Preamble that is not used in other CBRA (Concentration-Based Random Access) or CFRA (Concentration-Free Random Access) systems.

[0064] Subsequently, the base station device 200b transmits CSI-RS for CSI to the terminal device 100 after a certain period of time (N slot or N frame) has elapsed since receiving PRACH from the terminal device 100 (S27). Here, N may be a non-negative integer.

[0065] Then, for example, in S27, the terminal device 100 measures (receives) the CSI-RS for CSI transmitted from the base station device 200b and transmits the measurement result to the base station device 200a (S28).

[0066] In other words, the terminal device 100, for example, receives CSI-RS for CSI at a timing associated with the transmission of PRACH.

[0067] Specifically, terminal device 100 receives CSI-RS for CSI after a certain period of time (N slot or N frame) has elapsed since transmitting PRACH. Here, N may be a non-negative integer.

[0068] Furthermore, the terminal device 100 transmits the measurement device to the base station device 200a by using, for example, a transmission resource linked to the transmission resource used for transmitting CSI-RS for CSI in S27.

[0069] The information indicating the transmission timing of CSI-RS for CSI (for example, the constant time N) may be included in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S21, for example. Alternatively, the information indicating the transmission timing of CSI-RS for CSI may be described in the specifications, for example.

[0070] Furthermore, information indicating the transmission resources used for CSI-RS for CSI transmission may be included, for example, in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S21.

[0071] Furthermore, the transmission of the measurement results to the base station device 200a may, for example, occur after S30, which will be described later.

[0072] Subsequently, the base station device 200a, for example, in S28, transfers the CSI-RS for CSI measurement result transmitted from the terminal device 100 to the base station device 200b (S29).

[0073] Then, the base station device 200a, for example, in S22, determines whether or not to perform a Cell Switch based on the measurement results of SSB or CSI-RS for BM transmitted from the terminal device 100, and if it determines that a Cell Switch is necessary, it transmits a Cell Switch command to the terminal device 100 (S30).

[0074] As a result, the wireless communication system 10 in this embodiment can synchronize, for example, the timing at which the base station device 200b transmits CSI-RS for CSI with the timing at which the terminal device 100 measures (receives) CSI-RS for CSI.

[0075] Furthermore, the PDCCH order allows for the specification of, for example, the base station device 200b to which PRACH is transmitted. Therefore, in the wireless communication system 10 of this embodiment, for example, by performing the measurement of CSI-RS for CSI by the terminal device 100 (S28) after the transmission of the PDCCH order (S24) and the transmission of CSI-RS related information (S25), it becomes possible to suppress the transmission of CSI-RS for CSI from base station devices 200b that do not perform LTM, and the occurrence of CSI-RS for CSI measurements transmitted from base station devices 200b that do not perform LTM. Consequently, the wireless communication system 10 can suppress power consumption due to unnecessary processing, and can also suppress interference with other cells due to unnecessary transmission of CSI-RS for CSI.

[0076] The PDCCH Order transmitted in S24 may include, for example, information indicating whether or not CSI-RS for CSI transmission will be performed from the base station device 200b. Furthermore, the CSI-RS for CSI measured in S28 may be, for example, only the CSI-RS for CSI transmitted from the base station device 200b indicated by the PDCCH Order transmitted in S24. Additionally, the base station device 200a may transmit the CSI-RS resource set and / or CSI-RS resource index used for CSI-RS transmission to the base station device 200b.

[0077] A single CSI-RS resource set may contain one or more CSI-RS resources. Each of the CSI-RS resources included in the CSI-RS resource set may be assigned an index. For example, the base station device 200 may notify the terminal device 100 of the index of a CSI-RS resource and instruct it to transmit CSI-RS based on that CSI-RS resource. The CSI-RS resource may include information about the resource to which the CSI-RS is mapped, parameters related to the transmission power, a scrambling index, a period and offset, an antenna port used for CSI-RS transmission, and the like.

[0078] A CSI-RS resource may be associated with a CSI report that reports the results of channel measurements performed using the CSI-RS resource. The CSI report may be composed of a higher-level parameter CSI-ReportConfig. CSI-ReportConfig may include parameters necessary for sending the CSI report. For example, it may include the period of the CSI report, the resource to which the CSI report is mapped, and the type of measurement results included in the CSI report.

[0079] Furthermore, the CSI-RS resource set (a resource set including Antenna Port and transmission resources) used in S28 to transmit the measurement results of CSI-RS for CSI may be identified, for example, by the Preamble Index included in the RRC Configuration transmitted in S21. Also, the CSI-RS resources included in the CSI-RS resource set (a resource set including Antenna Port and transmission resources) used in S28 to transmit the measurement results of CSI-RS for CSI may be identified, for example, by the Preamble Index included in the RRC Configuration transmitted in S21. Furthermore, the CSI-ReportConfig in S28, which relates to the transmission of the measurement results of CSI-RS for CSI, may be associated one-to-one with, for example, the base station device 200b indicated by the PDCCH Order transmitted in S24.

[0080] Furthermore, the measurement results of CSI-RS for CSI in S28 may be reported directly to the base station device 200b by signals used in the random access procedure (e.g., Msg3 or MsgA).

[0081] Furthermore, in the wireless communication system 10 of this embodiment, the transmission timing and whether or not TCI State Activation or PRACH are performed do not affect the respective processes in this embodiment.

[0082] [Third Embodiment] Next, a third embodiment will be described. Figure 6 is a diagram showing an example of a sequence in the third embodiment.

[0083] The base station device 200a transmits, for example, the RRC Configuration for base station device 200b to the terminal device 100 (S31).

[0084] Furthermore, the base station device 200b transmits, for example, SSB or CSI-RS for BM to the terminal device 100 (S32).

[0085] Then, for example, in S32, the terminal device 100 measures (receives) the SSB or CSI-RS for BM transmitted from the base station device 200b and transmits the measurement result to the base station device 200a (S33).

[0086] Subsequently, the base station device 200a transmits, for example, information (CSI-RS related information) to the base station device 200b, including information about the transmission timing of CSI-RS for CSI and information about transmission resources (S34).

[0087] Specifically, if, for example, in S33, measurement results for multiple base station devices 200b are transmitted from the terminal device 100, the base station device 200a selects the base station device 200b with the best measurement result (e.g., RSRP) and transmits information to the selected base station device 200b.

[0088] Furthermore, the base station device 200a transmits, for example, a TCI State Activation for base station device 200b to the terminal device 100 (S35). Hereinafter, the TCI State Activation will also be referred to as the fourth signal.

[0089] Furthermore, the base station device 200a may, for example, transmit TCI State Activation multiple times to the terminal device 100 for each of the multiple base station devices 200b.

[0090] Subsequently, the base station device 200b transmits CSI-RS for CSI to the terminal device 100 at a timing specified by the base station device 200a, or after a certain period of time (N slot or N frame) has elapsed since the base station device 200a transmitted TCI State Activation to the terminal device 100 (S36). Here, N may be a non-negative integer.

[0091] Then, for example, in S36, the terminal device 100 measures (receives) the CSI-RS for CSI transmitted from the base station device 200b and transmits the measurement result to the base station device 200a (S37).

[0092] In other words, the terminal device 100 receives, for example, CSI-RS for CSI at a timing associated with the reception of TCI State Activation.

[0093] Specifically, the terminal device 100 measures (receives) the CSI-RS for CSI after a certain period of time (N slot or N frame) has elapsed since receiving the TCI State Activation. Here, N may be a non-negative integer.

[0094] Furthermore, the terminal device 100 transmits the measurement device to the base station device 200a by using, for example, a transmission resource linked to the transmission resource used for transmitting CSI-RS for CSI in S36.

[0095] The information indicating the transmission timing of CSI-RS for CSI (for example, the constant time N) may be included in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S31, for example. Alternatively, the information indicating the transmission timing of CSI-RS for CSI may be described in the specifications, for example.

[0096] Furthermore, information indicating the transmission resources used for CSI-RS for CSI transmission may be included, for example, in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S31.

[0097] Furthermore, the measurement of CSI-RS for CSI may be limited, for example, to CSI-RS for CSI transmitted from base station equipment 200b corresponding to the Candidate Cell to which the activated TCI state belongs.

[0098] Furthermore, the transmission of the CSI-RS for CSI measurement results to the base station device 200a may, for example, occur after S39, which will be described later.

[0099] Subsequently, the base station device 200a, for example, in S37, transfers the CSI-RS for CSI measurement result transmitted from the terminal device 100 to the base station device 200b (S38).

[0100] Then, the base station device 200a, for example, in S32, determines whether or not to perform a Cell Switch based on the measurement results of SSB or CSI-RS for BM transmitted from the terminal device 100, and if it determines that a Cell Switch is necessary, it transmits a Cell Switch command to the terminal device 100 (S39).

[0101] As a result, the wireless communication system 10 in this embodiment can synchronize, for example, the timing at which the base station device 200b transmits CSI-RS for CSI with the timing at which the terminal device 100 measures (receives) CSI-RS for CSI.

[0102] Furthermore, in the wireless communication system 10 of this embodiment, for example, by performing the measurement of CSI-RS for CSI by the terminal device 100 (S37) after the transmission of CSI-RS related information (S34) and the transmission of TCI State Activation (S35), it becomes possible to suppress the occurrence of unnecessary transmission and measurement of CSI-RS for CSI. Therefore, in the wireless communication system 10, for example, it becomes possible to suppress power consumption due to the execution of unnecessary processing, and to suppress the occurrence of interference with other cells due to unnecessary transmission of CSI-RS for CSI.

[0103] In the wireless communication system 10 of this embodiment, the transmission timing and whether or not PRACH is performed do not affect each of the processes in this embodiment.

[0104] [Fourth Embodiment] Next, a fourth embodiment will be described. Figure 7 is a diagram showing an example of a sequence in the fourth embodiment.

[0105] The base station device 200a transmits, for example, the RRC Configuration for base station device 200b to the terminal device 100 (S41).

[0106] Furthermore, the base station device 200b transmits, for example, SSB or CSI-RS for BM to the terminal device 100 (S42).

[0107] Then, for example, in S42, the terminal device 100 measures (receives) the SSB or CSI-RS for BM transmitted from the base station device 200b and transmits the measurement result to the base station device 200a (S43).

[0108] Subsequently, the base station device 200a transmits, for example, information (CSI-RS related information) to the base station device 200b, including information about the transmission timing of CSI-RS for CSI and information about transmission resources (S44).

[0109] Furthermore, the base station device 200a, for example, in S42, determines whether or not to perform a Cell Switch based on the measurement results of SSB or CSI-RS for BM transmitted from the terminal device 100. If it determines that a Cell Switch is necessary, it transmits a Cell Switch command (hereinafter also referred to as the fifth signal) to the terminal device 100 (S45).

[0110] In this case, the base station device 200a may include information about the CSI-RS for CSI transmission resources in the Cell Switch command, for example.

[0111] Then, the base station device 200b transmits, for example, CSI-RS for CSI to the terminal device 100 (S46).

[0112] Then, for example, in S46, the terminal device 100 measures (receives) the CSI-RS for CSI transmitted from the base station device 200b and transmits the measurement result to the base station device 200a (S47).

[0113] In other words, the terminal device 100 receives, for example, CSI-RS for CSI at a timing associated with the reception of Cell Switch command.

[0114] Specifically, the terminal device 100 measures (receives) the CSI-RS for CSI after a certain period of time (N slot or N frame) has elapsed since receiving a Cell Switch command. Here, N may be a non-negative integer.

[0115] Furthermore, the terminal device 100 transmits the measurement device to the base station device 200a by using, for example, a transmission resource linked to the transmission resource used for transmitting CSI-RS for CSI in S46.

[0116] The information indicating the transmission timing of CSI-RS for CSI may, for example, be included in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S41. Alternatively, the information indicating the transmission timing of CSI-RS for CSI may be described in the specifications, for example.

[0117] Furthermore, information indicating the transmission resources used for CSI-RS for CSI transmission may be included, for example, in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S41.

[0118] Furthermore, the CSI-RS for CSI measurement results may be transmitted to, for example, the base station device 200b. The destination for the transmission of the measurement results may be specified, for example, in the Cell Switch command. In addition, the transmission resource for the measurement results may be, for example, a resource that transmits UL (UpLink) to the base station device 200a after the completion of Cell switch.

[0119] Subsequently, the base station device 200a, for example, in S47, transfers the CSI-RS for CSI measurement result transmitted from the terminal device 100 to the base station device 200b (S48).

[0120] As a result, the wireless communication system 10 in this embodiment can synchronize, for example, the timing at which the base station device 200b transmits CSI-RS for CSI with the timing at which the terminal device 100 measures (receives) CSI-RS for CSI.

[0121] Furthermore, in the wireless communication system 10 of this embodiment, for example, by performing the measurement of CSI-RS for CSI by the terminal device 100 (S47) after the transmission of CSI-RS related information (S44) and the transmission of Cell Switch command (S45), it becomes possible to suppress the occurrence of unnecessary transmission and measurement of CSI-RS for CSI. Therefore, in the wireless communication system 10, for example, it becomes possible to suppress power consumption due to the execution of unnecessary processing, and to suppress the occurrence of interference with other Cells due to unnecessary transmission of CSI-RS for CSI.

[0122] In this embodiment, the transmission timing and execution status of TCI State Activation and PRACH in the wireless communication system 10 do not affect the processes in this embodiment.

[0123] [Fifth Embodiment] Next, a fifth embodiment will be described. Figure 8 is a diagram showing an example of a sequence in the fifth embodiment.

[0124] The base station device 200a transmits, for example, the RRC Configuration for base station device 200b to the terminal device 100 (S51).

[0125] Specifically, the base station device 200a performs settings, for example, including setting the event in Event Triggered Reporting.

[0126] Furthermore, the base station device 200b transmits, for example, SSB or CSI-RS for BM to the terminal device 100 (S52).

[0127] Then, the terminal device 100 measures (receives) the SSB or CSI-RS for BM transmitted from the base station device 200b in S52, and determines whether or not at least one of the events set in S51 has occurred. If it determines that at least one of the events set in S51 has occurred, the terminal device 100 transmits an Event-Trigger report to the base station device 200a, for example, including the measurement result of the SSB or CSI-RS for BM transmitted from the base station device 200b (S53).

[0128] Subsequently, the base station device 200a transmits, for example, information (CSI-RS related information) to the base station device 200b, including information about the transmission timing of CSI-RS for CSI and information about transmission resources (S54).

[0129] Specifically, if, for example, in S53, measurement results for multiple base station devices 200b are transmitted from the terminal device 100, the base station device 200a selects the base station device 200b with the best measurement result (e.g., RSRP) and transmits information to the selected base station device 200b.

[0130] Then, the base station device 200b transmits, for example, CSI-RS for CSI to the terminal device 100 (S55).

[0131] Then, for example, in S55, the terminal device 100 measures (receives) the CSI-RS for CSI transmitted from the base station device 200b and transmits the measurement result to the base station device 200a (S56).

[0132] In other words, the terminal device 100 performs, for example, the measurement (reception) of CSI-RS for CSI at a timing associated with the transmission of the Event-Trigger report.

[0133] Specifically, the terminal device 100 measures (receives) the CSI-RS for CSI after a certain period of time (N slots or N frames) has elapsed since transmitting the Event-Trigger report. Here, N may be a non-negative integer.

[0134] Furthermore, the terminal device 100 transmits the measurement device to the base station device 200a by using, for example, a transmission resource linked to the transmission resource used for transmitting CSI-RS for CSI in S55.

[0135] The information indicating the transmission timing of CSI-RS for CSI may, for example, be included in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S51. Alternatively, the information indicating the transmission timing of CSI-RS for CSI may be described in the specifications, for example.

[0136] Furthermore, information indicating the transmission resources used for CSI-RS for CSI transmission may be included, for example, in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S51.

[0137] Subsequently, the base station device 200a, for example, in S56, transfers the CSI-RS for CSI measurement results transmitted from the terminal device 100 to the base station device 200b (S57).

[0138] Then, the base station device 200a, for example, in S52, determines whether or not to perform a Cell Switch based on the measurement results of SSB or CSI-RS for BM transmitted from the terminal device 100, and if it determines that a Cell Switch is necessary, it transmits a Cell Switch command to the terminal device 100 (S58).

[0139] As a result, the wireless communication system 10 in this embodiment can synchronize, for example, the timing at which the base station device 200b transmits CSI-RS for CSI with the timing at which the terminal device 100 measures (receives) CSI-RS for CSI.

[0140] Furthermore, in the wireless communication system 10 of this embodiment, for example, by performing the measurement of CSI-RS for CSI by the terminal device 100 (S56) after the transmission of the Event-trigger report (S53) and the transmission of CSI-RS related information (S54), it becomes possible to suppress the occurrence of unnecessary transmission and measurement of CSI-RS for CSI. Therefore, in the wireless communication system 10, for example, it becomes possible to suppress power consumption due to the execution of unnecessary processing, and to suppress the occurrence of interference with other cells due to unnecessary transmission of CSI-RS for CSI.

[0141] Furthermore, if it is determined in S53 that there are multiple base station devices 200b where an event occurred, for example, base station device 200a may transmit CSI-RS related information to the base station device 200b with the best measurement result (e.g., RSRP) in S54. Alternatively, in this case, base station device 200a may transmit CSI-RS related information to each base station device 200b in order of the best measurement results. Alternatively, in this case, base station device 200a may transmit CSI-RS related information to each base station device 200b in ascending or descending order of CRI (CSI-RS resource indicator) or SSBRI (SS / PBCH block indicator). In this case, the base station device 200a may also transmit CSI-RS related information instructing each base station device 200b to set the CSI-RS for CSI transmission interval to a fixed interval (for example, N slot or N frame).

[0142] In this embodiment, the transmission timing and execution status of TCI State Activation and PRACH in the wireless communication system 10 do not affect the processes in this embodiment.

[0143] [Sixth Embodiment] Next, a sixth embodiment will be described. Figure 9 is a diagram showing an example of a sequence in the sixth embodiment.

[0144] The base station device 200a transmits, for example, the RRC Configuration for base station device 200b to the terminal device 100 (S61).

[0145] Furthermore, the base station device 200b transmits, for example, SSB or CSI-RS for BM to the terminal device 100 (S62).

[0146] Then, for example, in S62, the terminal device 100 measures (receives) the SSB or CSI-RS for BM transmitted from the base station device 200b and transmits the measurement result to the base station device 200a (S63).

[0147] Subsequently, the base station device 200a transmits, for example, information (CSI-RS related information) (CSI-RS related information) to the base station device 200b, including information about the transmission timing of CSI-RS for CSI and information about transmission resources (S64).

[0148] Specifically, if, for example, in S63, measurement results for multiple base station devices 200b are transmitted from the terminal device 100, the base station device 200a selects the base station device 200b with the best measurement result (e.g., RSRP) and transmits information to the selected base station device 200b.

[0149] Furthermore, the base station device 200a transmits, for example, a CSI-RS for CSI measurement instruction to the terminal device 100 (S65).

[0150] Specifically, the base station device 200a, for example, in the CSI Request field of the DCI format (e.g., DCI 0_1 or DCI 0_2), specifies the transmission resources to be used for transmitting and reporting CSI-RS for CSI. Hereinafter, the DCI format will also be referred to as the sixth signal.

[0151] Furthermore, the base station device 200a may, for example, specify to the terminal device 100 the base station device 200b to be measured for CSI-RS for CSI.

[0152] Then, the base station device 200b transmits, for example, CSI-RS for CSI to the terminal device 100 (S66).

[0153] Then, for example, in S66, the terminal device 100 measures (receives) the CSI-RS for CSI transmitted from the base station device 200b and transmits the measurement result to the base station device 200a (S67).

[0154] In other words, the terminal device 100 performs, for example, the measurement (reception) of CSI-RS for CSI at a timing associated with the reception of DCI format.

[0155] Specifically, the terminal device 100 measures (receives) the CSI-RS for CSI after a certain period of time (N slot or N frame) has elapsed since receiving the DCI format.

[0156] Furthermore, the terminal device 100 transmits the measurement device to the base station device 200a by using, for example, a transmission resource linked to the transmission resource used for transmitting CSI-RS for CSI in S66.

[0157] The information indicating the transmission timing of CSI-RS for CSI may, for example, be included in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S61. Furthermore, the information indicating the transmission timing of CSI-RS for CSI may, for example, be described in the specifications. Also, the information indicating the transmission timing of CSI-RS for CSI may, for example, be included in the DCI format transmitted from the base station device 200a to the terminal device 100 in S65.

[0158] Furthermore, information indicating the transmission resources used for CSI-RS for CSI transmission may be included, for example, in the RRC Configuration transmitted from the base station device 200a to the terminal device 100 in S61.

[0159] Subsequently, the base station device 200a, for example, in S67, transfers the CSI-RS for CSI measurement result transmitted from the terminal device 100 to the base station device 200b (S68).

[0160] Then, the base station device 200a, for example, in S62, determines whether or not to perform a Cell Switch based on the measurement result of SSB or CSI-RS for BM transmitted from the terminal device 100, and if it determines that a Cell Switch is necessary, it transmits a Cell Switch command to the terminal device 100 (S69).

[0161] As a result, the wireless communication system 10 in this embodiment can synchronize, for example, the timing at which the base station device 200b transmits CSI-RS for CSI with the timing at which the terminal device 100 measures (receives) CSI-RS for CSI.

[0162] Furthermore, in the wireless communication system 10 of this embodiment, for example, by performing the measurement of CSI-RS for CSI by the terminal device 100 (S66) after the transmission of CSI-RS related information (S64) and the transmission of DCI format (S65), it becomes possible to suppress the occurrence of unnecessary transmission and measurement of CSI-RS for CSI. Therefore, in the wireless communication system 10, for example, it becomes possible to suppress power consumption due to the execution of unnecessary processing, and to suppress the occurrence of interference with other cells due to unnecessary transmission of CSI-RS for CSI.

[0163] In the wireless communication system 10 of this embodiment, for example, in order to distinguish between a CSI-RS for CSI measurement instruction transmitted from base station device 200a and a CSI-RS for CSI measurement instruction transmitted from base station device 200b, a new DCI Field may be added in the DCI format transmitted from base station device 200a to terminal device 100 in S65, or different RNTIs may be used between base station device 200a and base station device 200b for scrambling PDCCH, or different CSI-RS for CSI transmission resources may be used between base station device 200a and base station device 200b.

[0164] Furthermore, in the wireless communication system 10 of this embodiment, the transmission timing and whether or not TCI State Activation or PRACH are performed do not affect the respective processes in this embodiment.

[0165] Furthermore, in each of the first to sixth embodiments, if the transmission of Aperiodic CSI-RS is set on the terminal device 100, the base station device 200b may, for example, transmit CSI-RS for CSI to the terminal device 100 after a certain period of time (N slot or N frame) has elapsed since receiving instructions from the base station device 200a.

[0166] Furthermore, in each of the first to sixth embodiments, if Semi-persistent CSI-RS transmission is set on the terminal device 100, the base station device 200a may transmit an Activation for CSI-RS for CSI transmission and an Indication for stopping CSI-RS for CSI transmission. In this case, the base station device 200b may, for example, receive an instruction from the base station device 200a, transmit CSI-RS for CSI N times, and then automatically stop transmitting CSI-RS for CSI.

[0167] Furthermore, in each of the first to sixth embodiments, if the transmission of Periodic CSI-RS is set in the terminal device 100, the terminal device 100 may, for example, transmit an Event-Trigger report and then configure the Window for measuring CSI-RS for CSI. Also, in this case, the base station device 200a may, for example, not issue a transmission instruction for CSI-RS for CSI to the base station device 200b.

[0168] Furthermore, in each of the first to sixth embodiments, the base station device 200a may, for example, instruct the terminal device 100 to provide a transmission resource that reports the measurement results of CSI-RS for CSI.

[0169] 10: Wireless communication system 100: Terminal device 110: CPU 120: Storage 121: Terminal communication program 122: Signal measurement program 130: Memory 150: Wireless communication circuit 151: Antenna 200: Base station device 210: CPU 220: Storage 221: Base station communication program 222: LTM control program 230: Memory 250: Wireless communication circuit 251: Antenna

Claims

1. A terminal device characterized by having: a measuring unit that measures the first signal transmitted from a second base station device in response to receiving instruction information regarding the first signal from a first base station device; and a transmitting unit that transmits the measurement results for the first signal to the first base station device.

2. The terminal device according to claim 1, characterized in that the first signal is CSI-RS for CSI.

3. The terminal device according to claim 1, further comprising a receiving unit for receiving a second signal transmitted from the second base station device, wherein the measuring unit measures the first signal at a predetermined time after the timing at which the receiving unit receives the second signal.

4. The terminal device according to claim 3, wherein the second signal is SSB or CSI-RS for BM.

5. The terminal device according to claim 1, wherein the transmitting unit transmits a third signal to the second base station device, and the measuring unit measures the first signal at a predetermined time after the timing at which the transmitting unit transmits the third signal.

6. The terminal device according to claim 5, wherein the third signal is PRACH.

7. The terminal device according to claim 1, further comprising a receiving unit for receiving a fourth signal transmitted from the first base station device, wherein the measuring unit measures the first signal at a predetermined time after the timing at which the receiving unit receives the fourth signal.

8. The terminal device according to claim 7, wherein the fourth signal is a TCI State Activation.

9. The terminal device according to claim 7, wherein the fourth signal is a Cell Switch Command.

10. The terminal device according to claim 7, wherein the fourth signal is DCI format.

11. The terminal device according to claim 1, wherein the transmitting unit transmits a fifth signal to the first base station device, and the measuring unit measures the first signal at a predetermined time after the timing at which the transmitting unit transmits the fifth signal.

12. The terminal device according to claim 11, wherein the fifth signal is an Event-Trigger report.

13. A base station device comprising: a transmitting unit that transmits instruction information relating to a first signal to another base station device; a receiving unit that receives measurement results for the first signal transmitted from a terminal device in response to the reception of the instruction information from the other base station device from the terminal device; and a transmitting unit that transmits the measurement results for the first signal received by the receiving unit to a second base station device.

14. A wireless communication system comprising a terminal device, a first base station device, and a second base station device, wherein the first base station device transmits instruction information relating to a first signal to the second base station device, the second base station device transmits the first signal in response to receiving the instruction information from the first base station device, the terminal device measures the first signal transmitted from the second base station device, the first base station device receives the measurement result for the first signal transmitted from the terminal device, and transmits the received measurement result for the first signal to the second base station device.

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