Terminal device, base station device, and wireless communication system
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- 1FINITY INC
- Filing Date
- 2024-11-07
- Publication Date
- 2026-05-15
Smart Images
Figure JP2024039626_15052026_PF_FP_ABST
Abstract
Description
Terminal device, base station device, and wireless communication system
[0001] The present invention relates to a terminal device, a base station device, and a wireless communication system.
[0002] In a wireless communication system, a terminal device measures the quality (such as RSRP) of one or more beams belonging to a cell to which it is wirelessly connected in order to determine an appropriate beam for receiving a signal from a base station. Also, the terminal device measures the quality (such as RSRP) of one or more beams belonging to adjacent cells other than the cell in which it is currently communicating or camping on (which may be referred to as the current cell) in order to switch to another cell as it moves. For example, the terminal device periodically measures the beams and transmits the measurement results to the base station device of the current cell.
[0003] However, in such beam management, for example, even a terminal device that is not moving has to transmit a report including measurement results periodically, resulting in a communication load in wireless communication.
[0004] Therefore, in order to reduce the communication load in report transmission, reports based on event triggers have been studied. The terminal device transmits a report to the base station device when a certain event trigger condition is satisfied. This reduces the number of transmissions of measurement results and reduces the communication load. The condition is, for example, that the wireless quality at the time of beam reception in the terminal device falls below a predetermined value.
[0005] Technologies related to reports based on event triggers are described, for example, in the following documents.
[0006] 3GPP TS 37.324 V17.0.03GPP TS 37.340 V18.0.03GPP TS 38.201 V18.0.03GPP TS 38.202 V18.4.03GPP TS 38.211 V18.4.03GPP TS 38.212 V18.4.03GPP TS 38.213 V18.4.03GPP TS 38.214 V18.4.03GPP TS 38.215 V18.3.03GPP TS 38.300 V18.3.03GPP TS 38.321 V18.3.03GPP TS 38.322 V18.1.03GPP TS 38.323 V18.3.03GPP TS 38.331 V18.3.0
[0007] However, terminal devices may periodically send reports after meeting certain conditions. In this case, even if the terminal device remains in a location with good wireless quality, the periodic report transmission will be repeated, increasing the communication load due to unnecessary report transmissions.
[0008] Therefore, this disclosure provides a terminal device, a base station device, and a wireless communication system that can appropriately stop periodic report transmission in event-triggered report transmission.
[0009] A terminal device that periodically transmits a report containing beam measurement results to a base station device when an event trigger condition is met, comprising: a measurement unit that measures the radio quality of a first beam and a surrounding second beam used by the terminal device; and a control unit that stops transmitting the report when instructed to change the first beam and the radio quality meets a stop condition.
[0010] One disclosure allows for the appropriate cessation of periodic report transmissions in event-triggered report sending.
[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 of report transmission when event trigger condition 1 is met. Figure 5 shows an example of the sequence of quality control processing after beam change. Figure 6 shows an example of the sequence when a condition mismatch is detected during quality monitoring. Figure 7 shows an example of the sequence when no condition mismatch is detected during quality monitoring.
[0012] [First Embodiment] The first embodiment will now be described.
[0013] Figure 1 shows an example of the configuration of a wireless communication system 10. The wireless communication system 10 includes base station devices 200-1 and 2 and a terminal device 100.
[0014] Base station devices 200-1 and 2 (hereinafter sometimes referred to as base station devices 200) are devices that wirelessly connect to terminal devices 100 and perform wireless communication, and are, for example, eNodeB or gNodeB (gNB). Base station devices 200 constitute one or more cells (communication areas).
[0015] Furthermore, the base station device 200 transmits downlink data using, for example, one or more beams, and uses the transmitted beams to communicate wirelessly with the terminal device 100. The downlink data may be any of the following signals: PDSCH, PDCCH, PBCH, CSI-RS, or SSB. Each beam constitutes a corresponding cell. Each beam may belong to a corresponding cell. Base station device 200-1 transmits downlink data using, for example, beams 1 to 3, and base station device 200-2 transmits downlink data using beam 4. Transmitting a beam may also mean transmitting data using a beam. Transmitting a beam may mean that the base station device 200 transmits downlink data using a beam. Transmitting a beam may also mean that the terminal device 100 transmits uplink data using a beam.
[0016] 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. The terminal device 100 communicates with the base station device 200 using a beam corresponding to the cell in which it is located. There may be one beam per cell, or there may be multiple beams per cell. Hereafter, beam changes include, for example, those that do not involve cell changes.
[0017] Furthermore, the terminal device 100 sends reports triggered by events. The details of the report sending process triggered by events, and the conditions that trigger report sending, will be described later.
[0018] <Example of Terminal Device 100 Configuration> Figure 2 is a diagram showing an example of the configuration of terminal device 100. Terminal device 100 includes a CPU (Central Processing Unit) 110, storage 120, memory 130, antenna 140, and wireless communication circuit 150.
[0019] Storage 120 is an auxiliary storage device such as flash memory, HDD (Hard Disk Drive), or SSD (Solid State Drive) that stores programs and data. Storage 120 stores the wireless communication program 121 and the report control program 122.
[0020] Memory 130 is an area for loading programs stored in storage 120. Memory 130 may also be used as an area for programs to store data.
[0021] The wireless communication circuit 150 is a device that communicates wirelessly with the base station device 200 via the antenna 140. The terminal device 100 transmits and receives signals (messages) with the base station device 200 via the wireless communication circuit 150.
[0022] The CPU 110 constructs a control unit and a measurement unit by executing the wireless communication program 121 and performs wireless communication processing. Wireless communication processing is the process of establishing a wireless connection with the base station device 200 and performing wireless communication. In wireless communication processing, the terminal device 100 performs wireless communication with the base station device 200, receives signals transmitted by the base station device 200, and transmits signals to the base station device 200.
[0023] The CPU 110 constructs the control unit and measurement unit and performs report control processing by executing the report control program 122. The report control processing involves measuring the beam and, if the conditions for an event trigger are met, sending a report including the beam measurement results to the base station device 200. The beam measurement targets, for example, the beam currently in use, the beam used before the beam change, and the peripheral beam (which the terminal device 100 can receive with a predetermined value or higher). The terminal device 100 also stops sending periodic reports when predetermined conditions are met during the report control processing. The beam currently in use or the beam used before the beam change is an example of the first beam. The beam currently in use may also be described as the beam used by the terminal device 100 or the beam to which the terminal device 100 is connected. The beam used before the beam change may also be described as the beam used by the terminal device 100 or the beam to which the terminal device 100 was connected. The peripheral beam is an example of the second beam.
[0024] <Example of Base Station Device 200 Configuration> Figure 3 shows an example of the configuration of a base station device 200. The base station device 200 includes a CPU 210, storage 220, memory 230, antenna 240, and wireless communication circuit 250.
[0025] Storage 220 is an auxiliary storage device such as flash memory, HDD, or SSD that stores programs and data. Storage 220 stores the wireless communication control program 221 and the report reception program 222.
[0026] Memory 230 is an area for loading programs stored in storage 220. Memory 230 may also be used as an area for programs to store data.
[0027] The wireless communication circuit 250 is a device that communicates wirelessly with the terminal device 100 via the antenna 240. The base station device 200 transmits and receives signals (messages) with the terminal device 100 via the wireless communication circuit 250.
[0028] The CPU 210 is a processor that loads programs stored in the storage 220 into the memory 230, executes the loaded programs, builds each part, and performs each process.
[0029] The CPU 210 constructs the beam control unit and receiver unit by executing the wireless communication control program 221 and performs wireless communication control processing. Wireless communication control processing is the process of controlling wireless communication with the terminal device 100. In the wireless communication control processing, the base station device 200 wirelessly connects with the terminal device 100, transmits signals to the terminal device 100, and receives signals from the terminal device 100.
[0030] The CPU 210 constructs the beam control unit and receiver unit by executing the report reception program 222 and performs beam report reception processing. Report reception processing is the process of receiving reports transmitted from the terminal device 100 at the base station equipment. The base station equipment 200 receives the report and, for example, instructs the terminal device 100 to change the beam or cell.
[0031] <Event Trigger Conditions> The conditions for event triggers are explained below. There are four types of event trigger conditions, for example. In the following explanation, the Beam of serving cell refers to the beam currently communicating, and the Beam of candidate cell refers to the beam transmitted by the cell that is a candidate to be changed (a candidate to move to). The current cell may be a serving cell. The adjacent cell may be a candidate cell. A serving cell may be included in a candidate cell. Furthermore, while reception quality is, for example, RSRP (Reference Signal Received Power), it may also refer to other radio qualities such as RSRQ (Reference Signal Received Quality) or SINR (Signal-to-Interference-plus-Noise Power Ratio). Received power may mean any of RSRP, RSRQ, or SINR. Received power may also refer to reception quality. For example, high reception quality may mean high received power.
[0032] Condition 1: The reception quality of the current cell's beam is lower than the first threshold (poor quality). Condition 2: The reception quality of the adjacent cell's beam is better than the reception quality of the current cell's beam by an offset amount. Condition 3: The reception quality of the adjacent cell's beam is higher than the second threshold (good quality). Condition 4: The reception quality of the current cell's beam is lower than the third threshold (poor quality), AND the reception quality of the adjacent cell's beam is higher than the fourth threshold (good quality). The third threshold may be the same value as the first threshold, or it may be a different value. The fourth threshold may be the same value as the second threshold, or it may be a different value.
[0033] Figure 4 shows an example of report transmission when event trigger condition 1 is met. In Figure 4, the vertical axis represents the received power of the current cell beam, and the horizontal axis represents time. The terminal device 100 measures signals R1 to R5, for example. Signal R1 does not satisfy condition 1 because its received power is above the first threshold. Signal R2 satisfies condition 1 because its received power is below the first threshold. The terminal device 100 starts a timer at this timing, for example, and monitors whether condition 1 is continuously met for a certain period (TTT: Time to Trigger). TTT may be defined as a certain period or as a predetermined number of times.
[0034] For example, the terminal device 100 determines that it will send a report (start sending periodic reports) because the received power of signals R2 to R4 during the TTT period is continuously lower than the first threshold.
[0035] The report transmitted by the terminal device 100 may include, for example, the measurement result of the last signal R5 that consecutively met the conditions, or the measurement result of the first signal thereafter. The report may also include, for example, measurement results corresponding to multiple beams, or it may include measurement results corresponding to a single beam.
[0036] Furthermore, the reference signal to be measured is, for example, CSI (Channel State Information)-RS (Reference Signal) or SSB (SS / PBCH Block). The report is, for example, a CSI report. The report is transmitted using MAC CE, for example, PUSCH. Alternatively, the report may be transmitted using UCI, or it may be transmitted using PUCCH, or it may be transmitted using UCI.
[0037] <Beam Change Instructions> When the terminal device 100 moves within the same cell, for example, it may change from the currently used beam 1 to a different beam 2 in the same cell. The currently used beam may be referred to as the current beam. The currently used beam may also be the beam indicated by the TCI State.
[0038] The base station device 200 receives, for example, a report from the terminal device 100 that includes the measurement results for beam 1 and beam 2. The base station device 200 may then decide to change the beam used by the terminal device 100 from beam 1 to beam 2, depending on the measurement results, and may instruct the terminal device 100 to do so. The beam used by the terminal device 100 may be the beam used for transmission and / or reception to the base station device 200. This instruction is, for example, included in a TCI (Transmission Configuration Indicator) State change and transmitted to the terminal device 100 using DCI (Downlink Control Information). Upon receiving the TCI State change, the terminal device 100 changes the beam it uses from beam 1 to beam 2. From then on, the beam of the terminal device 100's current cell becomes beam 2.
[0039] For example, if a beam change occurs while terminal device 100 is periodically transmitting reports, a determination is made as to whether terminal device 100 should continue transmitting reports. For instance, if terminal device 100 moves and remains in a position where the radio wave conditions of beam 2 are good, there is little need for terminal device 100 to transmit reports, and by stopping report transmission, efficient use of wireless resources becomes possible.
[0040] <Sequence> The following describes the sequence related to report transmission in event triggers.
[0041] Figure 5 shows an example of the sequence of quality control processing after beam change. Terminal device 100 receives an instruction to change the current beam from beam 1 to beam 2 (S10). The change instruction is included, for example, in the TCI State field transmitted via DCI.
[0042] When terminal device 100 receives a TCI State change, it changes the current beam from beam 1 to beam 2 (S11).
[0043] Upon receiving a TCI State change, the terminal device 100 starts the quality monitoring process S100. The quality monitoring process S100 is, for example, a process of monitoring whether the conditions of an event trigger are satisfied for a certain period. The certain period is, for example, TTT. Note that the beam of the current cell in the conditions of the event trigger may be the changed beam 2. The condition of the event trigger may be one, or may be a combination of conditions of a plurality of event triggers. Note that, in the case of a combination of conditions of a plurality of event triggers, satisfying the conditions may mean that all the conditions of the plurality of event triggers are satisfied.
[0044] For example, when the condition of the event trigger is Condition 1, the terminal device 100 checks in the quality monitoring process S100 whether the reception quality of beam 2 is lower than the first threshold (poor quality). If the reception quality is low, the quality monitoring process S100 is continued. The terminal device 100 may continue to monitor the reception quality of beam 2 until a certain period elapses. Then, when a certain period elapses, the terminal device 100 determines that the conditions of the event trigger are satisfied and may continue to transmit periodic reports.
[0045] On the other hand, the terminal device 100 checks in the quality monitoring process S100 whether the reception quality of beam 2 is equal to or higher than the first threshold (good quality). If the reception quality is equal to or higher than the first threshold, the quality monitoring process S100 is stopped. Then, the terminal device 100 determines that the conditions of the event trigger are not satisfied and may stop transmitting periodic reports.
[0046] Note that during the certain period (while the quality monitoring process is continuing), reports may or may not be transmitted. Also, the reports transmitted during the certain period may include measurement results related to the changed beam 2 or may include measurement results related to the beam 1 before the change.
[0047] FIG. 6 is a diagram showing an example of a sequence when a condition mismatch is detected during quality monitoring. The terminal device 100 may be in the middle of the quality monitoring process.
[0048] The terminal device 100 detects reception quality that does not satisfy the event trigger condition (S20). The reception quality that does not satisfy the event trigger condition means, for example, when the event trigger condition is condition 1, that the reception quality of one or more reference signals during the quality monitoring process was not less than the first threshold value.
[0049] When the terminal device 100 detects reception quality that does not satisfy the event trigger condition (S20), it may stop the continuous monitoring process (S21) and transmit a report suspension request to the base station device 200. The base station device 200 may be a base station device that transmits beam 2. The report suspension request may be a message for the terminal device 100 to request permission from the base station device 200 to suspend periodic report transmission.
[0050] For example, when the base station device 200 receives a report suspension request (S22), it transmits a report suspension response to the terminal device 100 (S23). The report suspension response may be a message for the base station device 200 to permit the terminal device 100 to stop periodic report transmission.
[0051] For example, when the terminal device 100 receives a report suspension response (S23), it stops periodic report transmission (S24).
[0052] In the sequence of FIG. 6, since the reception quality of beam 2 is good, it is highly likely that the terminal device 100 will not perform cell change (including beam change), so the need to monitor radio quality is reduced, and by stopping periodic report transmission, the use of radio resources is suppressed.
[0053] FIG. 7 is a diagram showing an example of a sequence when a condition mismatch is not detected during quality monitoring. The terminal device 100, for example, is in the middle of the quality monitoring process.
[0054] The terminal device 100 detects the elapse of a certain period (TTT) (timeout of the timer) without detecting reception quality that does not satisfy the event trigger condition (S30).
[0055] When the terminal device 100 detects the passage of a certain period of time (S30), it terminates the continuous monitoring process (S31) and sends a scheduling request to the base station device 200 requesting the allocation of wireless resources for report transmission (S32).
[0056] When the base station device 200 receives a scheduling request (S32), it allocates radio resources for PUSCH (Physical Uplink Shared Channel) transmission and sends UL_Grant to the terminal device 100 (S33). UL_Grant may also include information on the allocation of radio resources used for uplink data transmission.
[0057] When terminal device 100 receives UL_Grant (S33), it uses the allocated wireless resources and sends a report (S34).
[0058] Thereafter, the terminal device 100 continues to send periodic reports (S35). In subsequent report transmissions, for example, the process of receiving a reference signal, measuring wireless quality, and sending a report using the allocated wireless resources is repeated periodically.
[0059] In the sequence shown in Figure 7, because the reception quality of beam 2 is not good, for example, the terminal device 100 may change cells, and therefore the need to monitor wireless quality increases, and periodic report transmission continues.
[0060] In the first embodiment, the terminal device 100 can appropriately stop or continue periodic report transmission by monitoring whether or not the event trigger condition is met after the beam change.
[0061] [Second Embodiment] A second embodiment will now be described.
[0062] In the first embodiment, the terminal device 100 determined whether or not to stop the periodic report transmission. In the second embodiment, the base station device 200 makes the determination.
[0063] After switching beams, or after receiving a beam switching instruction (TSI State switching), the terminal device 100 includes the results of measuring the beam after the switch in the report and sends it to the base station device 200 (the current cell after the switch) at the timing of sending the report.
[0064] The base station device 200 decides whether or not to stop periodic report transmission depending on the reception quality of the beam after switching. If the base station device 200 decides to stop periodic report transmission, it sends an instruction to that effect to the terminal device 100. Methods for instructing the terminal device 100 to stop transmission include, for example, using DCI to instruct it to stop transmission or deactivating SP CSI reporting on PUSCH.
[0065] [Other Embodiments] In the first and second embodiments, when switching the target of measurement results to be included in the report from beam 1 to beam 2, the timing of the switch is, for example, the timing when a switch instruction (TSI State switch) is received, or the timing when the switch is actually completed after receiving the switch instruction.
[0066] Furthermore, in the first and second embodiments, the periodic report transmission during the TTT period may be temporarily stopped or continued.
[0067] Furthermore, in the first and second embodiments, a different period may be used instead of TTT. In this case, this different period may be instructed by the base station device 200, or it may be stored in advance by the terminal device 100.
[0068] Furthermore, in the first and second embodiments, the stop may be determined based on a single measurement result without providing a TTT period.
[0069] Furthermore, although the first and second embodiments are described using beam changes as an example, they may also be applied when a cell switch occurs. When a cell switch occurs, the current cell is changed, and the settings (Configuration) for measurement and reporting are also changed, so the measurement and reporting before the change will no longer work. Therefore, it is expected that report transmission will stop automatically without any special processing. However, if the settings being used are carried over even when a cell switch occurs, the report will not stop. In this case, the first and second embodiments may be applied when a cell switch occurs. Furthermore, means of stopping reporting when a cell switch occurs include, for example, sending a deactivation DCI before sending a CSC (Cell Switch Command), providing an indicator (1-bit information) to instruct deactivation in the CSC, or stopping reporting when a CSC is received. The CSC may be an instruction to change the cell from the current cell to one of the candidate cells from one or more candidate cells. The CSC may include the information necessary for the instruction to change the cell from the current cell to one of the candidate cells from one or more candidate cells. Any one of these candidate cells may be referred to as the target cell.
[0070] Furthermore, the event trigger conditions before the beam change (the event trigger conditions that triggered the transmission of periodic reports) and the event trigger conditions after the beam change may be the same or different. The base station device 200 may, for example, instruct the terminal device 100 on which conditions to use.
[0071] 10: Wireless communication system 100: Terminal device 110: CPU 120: Storage 121: Wireless communication program 122: Report control program 130: Memory 140: Antenna 150: Wireless communication circuit 200: Base station device 210: CPU 220: Storage 221: Wireless communication control program 222: Report reception program 230: Memory 240: Antenna 250: Wireless communication circuit
Claims
1. A terminal device that periodically transmits a report including beam measurement results to a base station device when an event trigger condition is met, comprising: a measurement unit that measures the radio quality of a first beam and a surrounding second beam used by the terminal device; and a control unit that stops transmitting the report when instructed to change the first beam and the radio quality meets a stop condition.
2. The terminal device according to claim 1, wherein the first beam and the second beam belong to the same cell.
3. The terminal device according to claim 1, wherein the wireless quality includes the received power of the beam.
4. The terminal device according to claim 1, wherein the stop condition includes the existence of measurement results that do not satisfy the first condition during the first period.
5. The terminal device according to claim 4, wherein the first condition is that the wireless quality of the modified beam is worse than a predetermined value.
6. The terminal device according to claim 4, wherein the first condition is that the wireless quality of the second beam is better than a predetermined value.
7. The terminal device according to claim 4, wherein the first condition is the same as the event trigger condition.
8. The terminal device according to claim 4, wherein the first period is the same as the period for monitoring whether or not the conditions for the event trigger are met.
9. A base station device comprising: a receiving unit that receives a report containing beam measurement results, which is periodically transmitted when a terminal device satisfies event trigger conditions; and a beam control unit that instructs the terminal device to change the beam being used, wherein the receiving unit receives a cancellation request requesting the cessation of transmission of the report, which is transmitted when the radio quality of the beam in the terminal device satisfies a stop condition; and the beam control unit transmits a cancellation response to the terminal device granting the request.
10. A wireless communication system in which a terminal device begins periodically transmitting a report containing beam measurement results to a base station device when an event trigger condition is met, the base station device receives the report and instructs the terminal device to change the beam it is using, and the terminal device stops transmitting the report if the radio quality of the measured beam meets a stop condition.
11. A base station device comprising: a receiving unit that receives a report containing beam measurement results, which is periodically transmitted when a terminal device satisfies the conditions of an event trigger; and a beam control unit that instructs the terminal device to change the beam it is using, wherein the control unit transmits a stop instruction to the terminal device to stop transmitting the periodic report if the measurement results of the modified beam satisfy predetermined conditions.