Communication system, base station, terminal device, and communication method

Abstract

Provided is a communication system comprising a base station and a terminal device. The base station transmits, to the terminal device, information pertaining to assignment of different physical resource blocks to respective events, and transmits a reference signal. Upon detecting an event as a result of receiving the reference signal, the terminal device notifies the base station of the type of the detected event by using the resource block assigned by the base station.

Description

Communication system, base station, terminal device, and communication method

[0001] This application claims priority to Japanese Patent Application No. 2024-132777, filed on August 8, 2024, the contents of which are incorporated herein by reference.

[0002] A technique relating to beamforming using MIMO (Multi-Input Multi-Output) is known (see, for example, Patent Document 1).

[0003] Special Publication No. 2012-533952

[0004] Currently, technologies for accelerating beam management are being discussed to achieve stability in millimeter wave beamforming using MIMO. Specifically, when a terminal device (User Equipment: UE) detects an event such as a drop in received signal power, the reporting delay when the terminal device attempts to report the event using reporting resources allocated by a base station has become non-negligible. Therefore, there is a demand for reducing such reporting delay.

[0005] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a communication system, a base station, a terminal device, and a communication method that can report an event detected by a terminal device to a base station without delay.

[0006] (1) One aspect of the present invention is a communication system including a base station and a terminal device, wherein the base station transmits information regarding allocation of different physical resource blocks for each event to the terminal device and transmits a reference signal, and when the terminal device detects an event as a result of receiving the reference signal, notifies the base station of the type of the detected event using the resource blocks allocated by the base station. (2) Another aspect of the present invention is the communication system of (1) above, wherein the base station allocates resources for a beam report to the terminal device according to the type of event notified by the terminal device, and the terminal device transmits a beam report regarding details of the detected event using the resources allocated by the base station. (3) Another aspect of the present invention is the communication system of (1) or (2) above, wherein the events for which the base station allocates different physical resource blocks include at least an event related to received signal power of a reference signal, and the base station allocates different physical resource blocks for each of a plurality of different events due to differences in the level of the received signal power. (4) In another aspect of the present invention, in the communication system of (3) above, the event in which the base station allocates different physical resource blocks includes an event in which, as a result of reception of a reference signal by the terminal device, there is a beam of better quality than the currently used beam, and an event in which there is one beam of better quality than the currently used beam and an event in which there are multiple beams of better quality than the currently used beam are detected as different events. (5) In another aspect of the present invention, in the communication system of any of (1) to (4) above, the physical resource blocks are allocated as resource blocks of different frequencies. (6) In another aspect of the present invention, in the communication system of any of (1) to (5) above, the physical resource blocks are allocated as resource blocks of different times.(7) According to another aspect of the present invention, in the communication system of any one of (1) to (6) above, the physical resource blocks are allocated as resource blocks that differ from each other in both frequency and time. (8) According to another aspect of the present invention, in the communication system of (1) above, the base station allocates to the terminal device in advance beam report resources according to a type of event notified by the terminal device, the terminal device transmits a beam report regarding details of the detected event using the resources allocated by the base station, and when the terminal device does not notify that an event has been detected, the base station diverts the pre-allocated beam report resources to a use other than the beam report. (9) According to another aspect of the present invention, a base station that communicates information with a terminal device transmits to the terminal device information regarding allocation of different physical resource blocks for each event and transmits a reference signal, and when the terminal device detects an event as a result of receiving the reference signal and is notified of the type of the event according to the allocated physical resource blocks, allocates beam report resources to the terminal device according to the notified type of event. (10) Another aspect of the present invention is a terminal device that communicates information with a base station, receives a reference signal transmitted from the base station, and when an event is detected as a result of receiving the reference signal, notifies the base station of the type of the detected event using physical resource blocks that are allocated by the base station and are different for each event, and transmits a beam report regarding details of the detected event using resources for beam reports that are allocated by the base station according to the type of event that has been notified.(11) Another aspect of the present invention is a communication method between a base station and a terminal device, comprising the steps of: transmitting, by the base station, information regarding the allocation of physical resource blocks that differ for each event to the terminal device; transmitting, by the base station, a reference signal; and, when the terminal device detects an event as a result of receiving the reference signal, notifying the base station of the type of the detected event using the resource blocks allocated by the base station.

[0007] According to the present invention, it is possible to provide a communication system, a base station, a terminal device, and a communication method that can report an event detected by a terminal device to a base station without delay.

[0008] FIG. 1 is a diagram for explaining a communication system according to an embodiment. FIG. 2 is a diagram for explaining timing for reporting observation results by the communication system according to the embodiment. FIG. 3 is a sequence diagram showing an example of a series of flows of a communication method performed by the communication system according to the embodiment. FIG. 4 is a block diagram showing an example of physical resource blocks allocated for each event by a base station according to the embodiment. FIG. 5 is a block diagram showing an example of the internal configuration of a base station or a terminal device according to the embodiment.

[0009] [Embodiments] Preferred embodiments of a communication system, a base station, a terminal device, and a communication method according to aspects of the present invention will be described in detail below with reference to the accompanying drawings. Note that aspects of the present invention are not limited to these embodiments and include various modifications or improvements. In other words, the components described below include those that can be easily imagined by a person skilled in the art or that are substantially identical, and the components described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the present invention. Furthermore, in the drawings below, the scale and number of components may differ from the scale and number of the actual components to make each configuration easier to understand.

[0010] In the following description, for convenience of explanation, terms and names defined in the 3GPP (registered trademark) LTE (3rd Generation Partnership Project Long Term Evolution) standard may be used. However, the present embodiment is not limited by such terms and names and may be applied to systems based on other standards.

[0011] 1 is a diagram illustrating a communication system according to an embodiment. The communication system 1 includes at least one base station 10 and at least one terminal device 30. In the illustrated example, the communication system 1 includes the base station 10, and terminal devices 30-1, 30-2, and 30-3.

[0012] The base station 10 communicates information with the terminal device 30. The base station 10 may also be called, for example, a next generation Node B (gNodeB or gNB), en-gNB, Next Generation-Radio Access Network (NG-RAN) node, eNB, low-power node, CU, DU, RU, gNB-DU, Remote Radio Head (RRH), Integrated Access and Backhaul / Backhauling (IAB) node, or the like.

[0013] The base station 10 is not limited to a single node, but may be configured with multiple nodes, such as a combination of lower nodes such as RUs (Radio Units) and DUs (Distributed Units) in an open radio access network (O-RAN) architecture and upper nodes such as CUs (Central Units).

[0014] The terminal device 30 is used by a user. Specific examples of the terminal device 30 include a smartphone, a tablet terminal device, a wearable device, etc. The terminal device 30 may also be called a user device, User Equipment (UE), etc.

[0015] The communication system 1 according to this embodiment performs beamforming using MIMO (Multiple Input Multiple Output) technology. Specifically, the base station 10 transmits a reference signal, and the terminal device 30 measures the received signal power of the reference signal. Based on the magnitude of the received signal power, the terminal device 30 detects an event, such as a decrease in received signal power. The terminal device 30 transmits the type and details of the detected event to the base station 10.

[0016] 2 is a diagram for explaining the timing of reporting observation results by the communication system according to this embodiment. With reference to the diagram, an example of the timing of reporting observation results by the communication system 1 will be explained in comparison with the conventional technique. The horizontal axis of the diagram indicates time.

[0017] First, at time t1, the terminal device 30 starts observing the beam transmitted from the base station 10. The base station 10 is equipped with, for example, a MIMO system having n antennas (n is a natural number equal to or greater than 1), and directional radio waves are transmitted in sequence from each of the n antennas. The terminal device 30 measures the received signal power of each of the n transmitted signals. The magnitude of the received signal power depends on the relative positional relationship between the base station 10 and the terminal device 30, etc.

[0018] Here, the received signal power may change due to factors such as a change in the relative positional relationship between the base station 10 and the user terminal device 30, the presence or absence of interference, etc. In the following description, a change detected as a result of beam observation performed at time t1 may be referred to as an event. An example of an event may be a sudden drop in received signal power. Other examples of events may include the observation of a beam of better quality than the beam in use, the quality of the beam in use falling below a predetermined threshold, or the observation of a beam of better quality than a candidate beam for use (activated). Note that the types of events targeted by the communication system 1 according to this embodiment are not limited to these examples.

[0019] In the past, when an event was detected at time t2, a report would be made using the original reporting resources as shown at time t4. However, waiting for the timing of the original reporting resources would result in a reporting delay. Therefore, according to this embodiment, the detection of an event at time t2 is used as a trigger to notify the base station 10 of the occurrence of an event, and a request for reporting resources corresponding to the event is made from the terminal device 30.

[0020] At time t3, the terminal device 30 uses the resources allocated as a result of the request to report the observation results.

[0021] According to this embodiment, there are multiple types of events detected as a result of beam observation. For example, when the terminal device 30 notifies the base station 10 of the occurrence of an event at time t2, the base station 10 allocates resources to the terminal device 30 for reporting the observation results at time t3. However, when the occurrence of an event is notified using one bit, the base station 10 cannot identify the type of event, and therefore needs to allocate resources sufficient to handle all events that may be reported. In other words, a problem arises in which the base station 10 must allocate excessive resources. More specifically, even if an event requires notification of only the identification information of one beam, there is a possibility that sufficient resources must be allocated to notify the radio wave intensities of multiple beams.

[0022] In other words, the conventional technology has a problem that when there are multiple possible events, it is not possible to identify which event is occurring. Also, since a report from the terminal device 30 to the base station 10 is generated only when an event occurs, blind decoding may be required.

[0023] In order to solve this problem, it is conceivable to use multi-bit notification of the occurrence of an event from the terminal device 30 to the base station 10. However, when using multi-bit notification, a problem arises in that the load becomes large.

[0024] Therefore, in this embodiment, the occurrence of an event is notified using a different resource for each event. The terminal device 30 notifies the occurrence of an event using a different resource for each event, which allows the base station 10 to identify the event that has occurred from the transmitted resource. By notifying the occurrence of an event using a different resource for each event, each notification is 1 bit, which has the effect of facilitating blind decoding.

[0025] 3 is a sequence diagram showing an example of a series of steps in a communication method performed by the communication system 1 according to this embodiment. Hereinafter, the series of steps in a communication method performed by the communication system 1 according to this embodiment will be described with reference to the same diagram.

[0026] (Step S11) First, the base station 10 sets an event. Specifically, the base station 10 sets an individual indication resource. More specifically, the base station 10 allocates a different physical resource block (PRB) for each event so that the terminal device 30 can perform notification with one bit. It can also be said that the base station 10 transmits information regarding the allocation of different physical resource blocks for each event to the terminal device 30.

[0027] The events targeted by the communication system 1 according to this embodiment include at least events related to the received signal power of a reference signal. The base station 10 may divide the level of the received signal power into multiple stages and assign each stage as a different event. In other words, the base station 10 assigns different physical resource blocks to each of multiple different events based on different levels of received signal power.

[0028] Furthermore, the events targeted by the communication system 1 according to this embodiment may include an event in which, as a result of receiving a reference signal by the terminal device 30, there is a beam of better quality than the currently used beam. In this case, the base station 10 may assign each of the beams to be reported as a different event. Specifically, the case in which there is one beam of better quality than the currently used beam and the case in which there are multiple beams of better quality may be detected as different events.

[0029] (Step S12) Next, the base station 10 transmits a reference signal. The reference signal may be transmitted by a known method used when performing beamforming in MIMO.

[0030] (Step S13) Next, the terminal device 30 observes the transmitted reference signal. Specifically, it measures the power strength of the received signal. The terminal device 30 detects an event based on the measured received signal power strength. If an event is detected, the following processing continues. However, there are cases where an event is not detected, such as when there is no external change between the previous reference signal transmission and the current reference signal transmission, or when the power strength of the received signal is sufficient. If an event is not detected, the following processing may not be performed and the processing may end.

[0031] (Step S14) When an event is detected, the terminal device 30 notifies the base station 10 of the occurrence of the event using resources corresponding to the detected event. Here, since a physical resource block PRB for notification is allocated for each event, the terminal device 30 can also be said to notify the type of the detected event. In other words, when the terminal device 30 detects an event as a result of receiving a reference signal, it can also be said that the terminal device 30 notifies the base station of the type of the detected event using the resource block allocated by the base station 10.

[0032] In step S14, the allocated 1-bit resource is used to notify only the occurrence of an event, without notifying details of the event. The 1-bit resource may be allocated to a PUCCH (Physical Uplink Control Channel). The PUCCH is a channel used to transmit A / N responses to downlink data, channel quality reports, and uplink bandwidth allocation requests.

[0033] Here, depending on the situation, it is assumed that multiple events occur simultaneously. For example, it is assumed that an event indicating that the received signal power has decreased and an event indicating that a beam with a higher received signal power than the currently used beam has been found may occur simultaneously. In such a case, the terminal device 30 can notify the base station 10 that multiple events are occurring simultaneously by using multiple resources allocated for each event.

[0034] (Step S15) Next, the base station 10 identifies an event from the resources sent from the terminal device 30. The base station 10 determines a resource for reporting according to the identified event. Note that the event type and the resource for reporting may be associated in advance. In this case, the base station 10 may refer to a table in which the associations have been made in advance and search for a resource for reporting according to the identified event.

[0035] (Step S16) Furthermore, the base station 10 allocates the determined report resources. The base station 10 can also allocate beam report resources to the terminal device 30 according to the type of event notified by the terminal device 30.

[0036] (Step S17) Next, the terminal device 30 transmits a beam report regarding details of the detected event using the resources allocated to the base station 10. Here, according to the present embodiment, since suitable resources are allocated depending on the type of event detected by the terminal device 30, the terminal device 30 can preferably report the event.

[0037] A specific example of an event may be an event indicating that the received signal power is equal to or less than XX [dB]. In such a case, the urgency may be high and the amount of reports may be small. Another specific example of an event may be an event indicating that a beam of better quality than the designated beam has been observed. In such a case, the urgency may be low and the amount of reports may be large. According to this embodiment, since suitable resources are allocated according to the type of event detected by the terminal device 30, the terminal device 30 can preferably report the event.

[0038] Note that the example shown in the figure describes an example in which the base station 10 allocates resources for beam reports in response to a detected event. However, this embodiment is not limited to this example. For example, the base station 10 may be configured to allocate resources for beam reports in advance, and if there is no notification from the terminal device 30, divert the resources for beam reports to a purpose other than beam reports. That is, the base station 10 may allocate resources for beam reports to the terminal device 30 in advance according to the type of event notified by the terminal device 30, and if there is no notification from the terminal device 30 that an event has been detected, divert the previously allocated resources for beam reports to a purpose other than beam reports.

[0039] 4 is a block diagram showing an example of physical resource blocks allocated for each event by the base station according to this embodiment. An example of the physical resource blocks allocated in step S11 will be described with reference to the figure. The horizontal axis of the figure represents the time axis, and the vertical axis represents the frequency axis.

[0040] As shown in the figure, physical resource blocks PRB according to this embodiment are allocated as resource blocks with different frequencies. Specifically, in the example shown in the figure, physical resource blocks PRB1, PRB2, and PRB3 are allocated. That is, by allocating as shown in the figure, three types of events can be identified. Note that the number of events is not limited to the example of three shown in the figure, and may be two or more.

[0041] In addition, the allocation method of physical resource blocks PRB according to this embodiment is not limited to the example of different frequencies as shown in the figure, but may be different in time. For example, physical resource blocks PRB1 to PRB3 may be allocated as different resources in the time direction. Physical resource blocks PRB that differ in the time direction can also be said to be different symbols.

[0042] In addition, as an example of a method of allocating physical resource blocks PRB according to this embodiment, both frequency and time may be varied. For example, when the number of events to be distinguished from each other increases, it may be possible to distinguish which event has occurred by varying both frequency and time.

[0043] The terminal device 30 notifies the occurrence of an event by using a resource corresponding to the event that has occurred among the allocated physical resource blocks PRB. Specifically, the terminal device 30 notifies the occurrence of the event by transmitting FirstPUCCH using the physical resource block PRB that corresponds to the event that has occurred. If no event has occurred, the allocated resource is not used.

[0044] [Internal Configuration] FIG. 5 is a block diagram showing an example of the internal configuration of a base station or terminal device according to this embodiment. At least some of the functions of the base station 10 or terminal device 30 can be implemented using a computer. As shown in the figure, the computer includes a central processing unit (processor) 901, a RAM 902, an input / output port 903, input / output devices 904 and 905, and a bus 906. The computer itself can be implemented using existing technology. The central processing unit 901 executes instructions contained in a program read from the RAM 902 or the like. In accordance with each instruction, the central processing unit 901 writes data to the RAM 902, reads data from the RAM 902, and performs arithmetic and logical operations. The RAM 902 stores data and programs. Each element included in the RAM 902 has an address and can be accessed using the address. Note that RAM is an abbreviation for "random access memory." The input / output port 903 is a port through which the central processing unit 901 exchanges data with external input / output devices, etc. The input / output devices 904 and 905 are input / output devices. The input / output devices 904 and 905 exchange data with the central processing unit 901 via the input / output port 903. The bus 906 is a common communication path used within the computer. For example, the central processing unit 901 reads and writes data from the RAM 902 via the bus 906. Also, for example, the central processing unit 901 accesses the input / output port via the bus 906. Furthermore, all or part of the functional units provided in the base station 10 or the terminal device 30 may be realized using hardware such as an ASIC, a PLD, or an FPGA. Furthermore, all or part of the functional units may be realized by a combination of software and hardware.

[0045] [Summary of the Embodiment] According to the embodiment described above, the communication system 1 includes a base station 10 and a terminal device 30. The base station 10 transmits information regarding the allocation of physical resource blocks (PRBs) that differ for each event to the terminal device 30, and transmits a reference signal. When the terminal device 30 detects an event as a result of receiving the reference signal, it notifies the base station of the type of the detected event using the resource blocks allocated by the base station 10. By adopting such a configuration, the communication system 1 can quickly notify the base station 10 of the type of event that has occurred in the terminal device 30. According to the present embodiment, when an event is detected by the terminal device 30, the type of the event that has occurred is notified from the terminal device 30 to the base station 10 without waiting for the original reporting resource. Therefore, according to the present embodiment, the type of the event that has occurred can be reported to the base station 10 without delay.

[0046] Furthermore, according to this embodiment, the base station 10 allocates beam report resources to the terminal device 30 according to the type of event notified by the terminal device 30. Furthermore, the terminal device 30 transmits a beam report regarding details of the detected event using the resources allocated by the base station 10. By adopting such a configuration, the terminal device 30 can provide a detailed beam report to the base station 10 while using the minimum necessary resources. In other words, according to this embodiment, details of the event that has occurred can be reported to the base station 10 without delay, without waiting for the original reporting resources.

[0047] Furthermore, according to this embodiment, the types of events also include differences in degree. In other words, when the degree of received signal power, etc., is different, they are allocated as different events. That is, events for which the base station 10 allocates different physical resource blocks (PRBs) include at least events related to the received signal power of a reference signal, and the base station 10 allocates different physical resource blocks (PRBs) for each of a plurality of different events due to different degrees of received signal power. By adopting such a configuration, when a 1-bit report is sent from the terminal device 30 to the base station 10, the base station 10 can obtain information regarding the degree, such as the level of received signal power. Therefore, according to this embodiment, detailed information about an event that has occurred, such as received signal power, can be reported to the base station 10 without delay, without waiting for the original reporting resource.

[0048] Furthermore, according to this embodiment, when the number of target beams differs, they are allocated as different events. In other words, the event in which the base station 10 allocates different physical resource blocks PRBs includes an event in which, as a result of receiving a reference signal by the terminal device 30, there is a beam of better quality than the currently used beam, and the cases in which there is one beam of better quality than the currently used beam and the cases in which there are multiple beams of better quality than the currently used beam are detected as different events. By adopting such a configuration, when the terminal device 30 reports 1 bit to the base station 10, the base station 10 can obtain information such as how many beams of better quality exist than the currently used beam. Therefore, according to this embodiment, the base station 10 can allocate appropriate resources required for the beam report.

[0049] Furthermore, according to this embodiment, the physical resource blocks PRB are allocated as resource blocks having different frequencies. By adopting such a configuration, it is possible to suppress the occurrence of delays.

[0050] Furthermore, according to this embodiment, the base station 10 allocates to the terminal device 30 in advance beam report resources according to the type of event notified by the terminal device 30, the terminal device 30 transmits a beam report relating to details of the detected event using the resources allocated by the base station 10, and if the base station 10 has not received notification that an event has been detected by the terminal device 30, it diverts the pre-allocated beam report resources to a use other than the beam report. According to this embodiment, even if beam report resources are allocated in advance, by diverting the resources to another use, it is possible to improve resource utilization efficiency and speed up communication.

[0051] Furthermore, according to this embodiment, the base station 10 communicates information with the terminal device 30. The base station 10 transmits information regarding the allocation of different physical resource blocks for each event to the terminal device 30, transmits a reference signal, and when an event is detected as a result of the terminal device 30 receiving the reference signal and the type of the event is notified according to the allocated physical resource block PRB, the base station 10 allocates beam report resources to the terminal device 30 according to the notified type of event. By adopting such a configuration, the base station 10 can know the type of the event that has occurred. According to this embodiment, when an event is detected by the terminal device 30, the base station 10 is notified of the type of the event that has occurred without waiting for the original reporting resource. Therefore, according to this embodiment, the base station 10 can know the type of the event that has occurred without delay.

[0052] Furthermore, according to this embodiment, the terminal device 30 communicates information with the base station 10. The terminal device 30 receives a reference signal transmitted from the base station 10, and when an event is detected as a result of receiving the reference signal, the terminal device 30 notifies the base station 10 of the type of the detected event using physical resource blocks (PRBs) allocated by the base station 10, which differ for each event, and transmits a beam report regarding details of the detected event using beam report resources allocated by the base station 10 according to the notified type of event. By adopting such a configuration, the terminal device 30 is able to transmit the type of the event that has occurred. According to this embodiment, when an event is detected, the terminal device 30 notifies the type of the event that has occurred without waiting for the original reporting resources. Therefore, according to this embodiment, the terminal device 30 is able to transmit the type of the event that has occurred without delay.

[0053] Furthermore, with the above-described embodiment, for example, "when an event is detected by a terminal device, it is reported to a base station without delay," which makes it possible to contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which is to "build resilient infrastructure, promote sustainable industrialization, and foster innovation."

[0054] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present invention.

[0055] Furthermore, a computer program for implementing the functions of each of the above-described devices may be recorded on a computer-readable recording medium, and the program may be read and executed by a computer system. The term "computer system" may also include hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a DVD (Digital Versatile Disc), or a storage device such as a hard disk built into a computer system.

[0056] Furthermore, the term "computer-readable recording medium" also includes a storage medium that stores a program for a certain period of time, such as a volatile memory (e.g., DRAM (Dynamic Random Access Memory)) within a computer system that serves as a server or client when the program is transmitted via a network such as the Internet or a communication line such as a telephone line. The program may also be transmitted from a computer system that stores the program in a storage device or the like to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has the function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may also be a program that realizes part of the aforementioned functions. Furthermore, the program may be a so-called differential file (differential program) that can realize the aforementioned functions in combination with a program already recorded in the computer system.

[0057] According to the present invention, when an event is detected by a terminal device, it can be reported to a base station without delay.

[0058] 1... communication system, 10... base station, 30... terminal device 30, PRB... physical resource block

Claims

1. A communication system including a base station and a terminal device, wherein the base station transmits to the terminal device information regarding allocation of different physical resource blocks for each event and transmits a reference signal, and when the terminal device detects an event as a result of receiving the reference signal, the terminal device notifies the base station of the type of the detected event using the resource blocks allocated by the base station.

2. The communication system of claim 1, wherein the base station allocates resources for beam reports to the terminal device according to the type of event notified by the terminal device, and the terminal device transmits a beam report regarding details of the detected event using the resources allocated by the base station.

3. The communication system according to claim 1 or 2, wherein the events for which the base station allocates different physical resource blocks include at least an event related to the received signal power of a reference signal, and the base station allocates different physical resource blocks for each of a plurality of different events due to differences in the level of the received signal power.

4. The communication system of claim 3, wherein the event in which the base station allocates different physical resource blocks includes an event in which, as a result of reception of a reference signal by the terminal device, there is a beam of better quality than the beam currently being used, and the cases in which there is one beam of better quality than the beam currently being used and the cases in which there are multiple beams of better quality than the beam currently being used are detected as different events.

5. The communication system according to claim 1 or 2, wherein the physical resource blocks are allocated as resource blocks having different frequencies.

6. The communication system according to claim 1 or 2, wherein the physical resource blocks are allocated as resource blocks that are different in time from each other.

7. The communication system according to claim 1 or 2, wherein the physical resource blocks are allocated as resource blocks that differ from each other in both frequency and time.

8. The communication system of claim 1, wherein the base station allocates to the terminal device in advance beam report resources according to the type of event notified by the terminal device, the terminal device transmits a beam report regarding details of the detected event using the resources allocated by the base station, and if the terminal device does not notify the base station that an event has been detected, the base station converts the pre-allocated beam report resources to a purpose other than beam reporting.

9. A base station that communicates information with a terminal device, which transmits information to the terminal device regarding the allocation of different physical resource blocks for each event, transmits a reference signal, and when an event is detected as a result of the terminal device receiving the reference signal and the type of the event is notified according to the allocated physical resource block, allocates resources for beam reports to the terminal device according to the notified type of event.

10. A terminal device that communicates information with a base station, receiving a reference signal transmitted from the base station, and when an event is detected as a result of receiving the reference signal, notifying the base station of the type of the detected event using physical resource blocks that are allocated by the base station and that differ for each event, and transmitting a beam report regarding details of the detected event using beam report resources that are allocated by the base station according to the notified type of event.

11. A communication method between a base station and a terminal device, comprising: a step of transmitting, by the base station, to the terminal device, information regarding the allocation of physical resource blocks that differ for each event; a step of transmitting a reference signal by the base station; and a step of notifying the base station of the type of the detected event by the terminal device, when the terminal device detects an event as a result of receiving the reference signal, using the resource blocks allocated by the base station.

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