Base station device, control method, program, and terminal device configured to be capable of performing high-speed beam control

Abstract

This terminal device measures the radio quality of a signal transmitted from each of a plurality of first beams, from among a plurality of beams formed by a connected base station device, that have been enabled for communication between the base station device and the terminal device and each of second beams, from among the plurality of beams, that constitute at least a portion of the beams not included in the first beams, and the terminal device transmits a prescribed report to the base station device on the basis of the result of the measurement of the radio quality. On the basis of the prescribed report, the base station device designates a third beam from among the first beams and designates a fourth beam from among the second beams. The terminal device receives, from the base station device, downlink control information (DCI) including first information that indicates that the third beam is to be disabled and the fourth beam is to be enabled and second information that designates a beam to be used by the base station device during the communication between the base station device and the terminal device.

Description

Terminal device, base station device, control method, and program configured to perform high-speed beam control

[0001] The present invention relates to a wireless communication technology that enables and uses some of multiple beams.

[0002] The fifth generation (5G) standard of the Third Generation Partnership Project (3GPP (registered trademark)) defines the concept of a Transmission Configuration Indicator (TCI). A different reference signal resource is associated with each of a plurality of beams, and a TCI state is associated with the resource. As a result, a separate TCI state is associated with each of a large number of beams formed by a base station device, for example. When communicating with a terminal device using one of the beams, the base station device notifies the terminal device of information specifying the TCI state corresponding to that beam, allowing the terminal device to perform signal reception and transmission processing appropriate for that beam.

[0003] A base station device indicates the TCI state corresponding to the beam to be used using three bits in downlink control information (DCI). However, three bits of information can only represent eight different types of information, which is generally fewer than the number of beams formed by the base station device. Therefore, among the TCI states corresponding to each beam formed by the base station device, the number of TCI states to be enabled is limited to eight (or less) in advance. The base station device notifies the terminal device of information specifying the eight enabled TCI states, for example, using a message in the radio resource control (RRC) layer or medium access control (MAC) layer. Then, in subsequent communications, the base station device can specify one of the eight TCI states using DCI.

[0004] As described above, the number of enabled TCI states is limited to eight or less, and the setting is performed by transmitting, for example, a message of the RRC layer or MAC layer from the base station device to the terminal device. Therefore, in order to be able to use other beams associated with TCI states other than the eight or less enabled TCI states, it is necessary to transmit and receive RRC messages again, and this change requires a certain amount of time. Therefore, when the environment of the terminal device changes rapidly, it is not easy to quickly adapt the enabled TCI state to the change.

[0005] The present invention provides a technique that enables adaptively setting a set of beams to be activated even in an environment where the communication environment changes rapidly.

[0006] A terminal device according to one aspect of the present invention has: a measurement means for measuring the wireless quality of signals transmitted from each of a plurality of first beams, among a plurality of beams formed by a base station device currently connected, that are enabled for communication between the base station device and the terminal device, and each of a plurality of second beams that are at least a portion of the beams not included in the first beams; a transmission means for transmitting a predetermined notification to the base station device based on the results of the wireless quality measurement; a reception means for receiving from the base station device, based on the predetermined notification, downlink control information (DCI) including first information indicating that a third beam is designated from among the first beams and a fourth beam is designated from among the second beams, thereby disabling the third beam and enabling the fourth beam, and second information specifying a beam to be used at the base station device in communication between the base station device and the terminal device; an update means for updating the first beam by removing the third beam from the first beams and adding the fourth beam; and a communication means for communicating with the base station device using settings corresponding to the beam designated by the second information from among the updated first beams.

[0007] A base station device according to one aspect of the present invention comprises: a transmitting means for forming a plurality of beams including a plurality of first beams that are enabled for communication between the base station device and a terminal device and transmitting signals; a receiving means for receiving a predetermined notification from the terminal device based on results of measuring the radio quality of signals transmitted from each of the first beams and each of second beams that are at least some of the beams not included in the first beams among the plurality of beams; a notifying means for notifying the terminal device, based on the predetermined notification, using downlink control information (DCI), of first information indicating that a third beam is designated from among the first beams and a fourth beam is designated from among the second beams, the third beam is disabled, and the fourth beam is enabled, and second information specifying a beam to be used in the base station device in communication between the base station device and the terminal device; and a communication means for communicating with the terminal device using settings corresponding to the beam designated by the second information from among the first beams updated by removing the third beam from the first beams and adding the fourth beam.

[0008] According to the present invention, it is possible to adaptively set a group of beams to be activated even in an environment where the communication environment changes rapidly.

[0009] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals.

[0010] The accompanying drawings are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention, and are used, together with the description, to explain the principles of the present invention. FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system. FIG. 2 is a diagram illustrating an example of conventional beam selection control processing. FIG. 3 is a diagram illustrating an example of beam selection control processing according to this embodiment. FIG. 4A is a diagram illustrating processing for enabling and disabling a beam. FIG. 4B is a diagram illustrating processing for enabling and disabling a beam. FIG. 4C is a diagram illustrating processing for enabling and disabling a beam. FIG. 5 is a diagram illustrating another example of beam selection control processing according to this embodiment. FIG. 6 is a diagram illustrating an example of the hardware configuration of a base station device and a terminal device. FIG. 7 is a diagram illustrating an example of the functional configuration of a terminal device. FIG. 8 is a diagram illustrating an example of the functional configuration of a base station device.

[0011] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. Furthermore, the same reference numerals are used to designate identical or similar components, and redundant descriptions will be omitted.

[0012] 1 shows an example of the configuration of a wireless communication system according to this embodiment. This wireless communication system is, for example, a cellular communication system conforming to the 5th generation (5G) cellular communication standard of the 3rd Generation Partnership Project (3GPP (registered trademark)) or its successor standard. However, this is just an example, and the present invention can be applied to other wireless communication systems having similar functions.

[0013] This wireless communication system includes, for example, a base station device 101 and a terminal device 102. The base station device 101 is capable of forming multiple beams 111 and is configured to use one of the multiple beams 111 to communicate with the terminal device 102. If the base station device 101 can always use all of the multiple beams 111, the number of bits of information specifying the beam when selecting one beam to actually use from the multiple beams 111 will be large. For example, to select one of 64 beams, 6 bits of information are required. For this reason, in a 5G system, for example, only 8 or fewer beams are available, such as the first beam 112 of the multiple beams 111 shown in FIG. 1 , and the beam to actually use among them can be expressed with 3 bits. At this time, the eight or fewer first beams 112 that are made available (enabled) are notified to the terminal device 102 by, for example, a Beam Activation Command transmitted from the base station device 101 via a message of the radio resource control (RRC) layer or medium access control (MAC) layer. The terminal device 102 activates the eight or fewer first beams 112 specified by the command and disables beams other than the first beams 112 among the multiple beams 111. Here, codepoints for identifying each of the eight or fewer beams are assigned. Then, the terminal device 102 receives downlink control information (DCI) from the base station device 101, in which the beams to be used in subsequent communications are specified by the codepoints. As a result, the terminal device 102 can communicate with the base station device 101 using the beams corresponding to the codepoints specified by the DCI. An example of the flow of this process is shown in FIG. 2. It should be noted that FIG. 2 is intended to provide an overview of the processing executed between the base station device 101 and the terminal device 102, and does not necessarily show all of the processing.

[0014] 2, first, the terminal device 102 observes a reference signal (e.g., a channel state information-reference signal (CSI-RS), a synchronization signal (SS) / physical broadcast channel (PBCH) block (SSB), etc.) transmitted from the base station device 101 and measures radio quality (S201). Then, the terminal device 102 reports the measurement results to the base station device 101 (S202). Based on the measurement results, the base station device 101 determines to activate a predetermined number of first beams 112 from among the multiple beams 111, for example, from those with better radio quality (S203). Furthermore, the base station device 101 determines to disable beams from among the multiple beams 111 that are not included in the first beams 112. Then, the base station device 101 notifies the terminal device 102 of the first beam 112 to be activated and the beam to be deactivated, for example, by a Beam Activation Command included in a message of the RRC layer or MAC layer (S204). Then, the terminal device 102 transmits an acknowledgement (HARQ (composite automatic repeat request)-ACK) to the base station device 101 in response to successfully receiving the notification. As a result, the base station device 101 confirms that the first beam 112 of the multiple beams 111 has been activated in the terminal device 102, and can then specify one beam from the first beam 112 by DCI to perform communication. Meanwhile, the other beams of the multiple beams 111 are deactivated, and cannot be specified by DCI. Then, when performing downlink or uplink communication, the base station device 101 selects a beam to use from the first beam 112, transmits a DCI including a codepoint value specifying that beam to the terminal device 102 (S206), and performs communication using that beam (S207).

[0015] As shown in Fig. 2 , in the conventional method, a beam cannot be designated by DCI until the processes from S201 to S204 have been performed. Furthermore, the beam that can be designated by DCI is limited to only the first beam 112 designated as the beam to be activated in S204. For this reason, for example, even if the radio quality of any beam other than the first beam 112 among the multiple beams 111 in the terminal device 102 is better than the radio quality of the first beam 112, in order to use that beam, the processes from S201 to S204 must be repeated, and it may be assumed that an appropriate beam cannot be used in a timely manner.

[0016] In view of the above circumstances, the present embodiment provides a process for quickly completing the setting of the beams to be enabled / disabled.

[0017] In one example of this embodiment, the terminal device 102 performs wireless quality measurements on each of the first beams 112 currently enabled among the multiple beams 111 of the base station device 101, and on second beams that are at least a portion of the beams other than the first beams 112. Then, based on the wireless quality measurement results, the terminal device 102 transmits a report to the base station device 101 specifying the third and fourth beams in order to disable a predetermined number of third beams that are part of the current first beams 112 and enable a fourth beam that is equal to or less than the predetermined number of fourth beams among the second beams. Upon receiving this information, the base station device 101 disables the third beam from among the beams included in the first beams 112, and newly enables the fourth beam and adds it to the first beams 112. According to this, the procedure in which the measurement results are notified to the base station device 101, information on the beam to be enabled / disabled is notified from the base station device 101 to the terminal device 102, and HARQ-ACK is transmitted from the terminal device 102 to the base station device 101 is shortened to a procedure in which only a report is made from the terminal device 102. As a result, the beam enabling / disabling process can be completed in a short period of time, and an appropriate beam can be used at the appropriate time.

[0018] 3 shows an example of the processing flow in this case. First, the terminal device 102 transmits capability information indicating whether or not the terminal device 102 has the capability to set a beam to be enabled / disabled on its side (i.e., the capability described below) (S301). The terminal device 102 may notify this capability information, for example, when connecting to the base station device 101. The capability information may be transmitted from the terminal device 102 to the base station device 101 in response to a predetermined request transmitted by the base station device 101 to the terminal device 102. The terminal device 102 may notify this capability information before the first beam 112 is initially set, or may notify this capability information after the first beam 112 is set. If the terminal device 102 naturally has the capability to perform the processing described below, or if the base station device 101 has been notified of its capability by another method, the notification of this capability information may be omitted.

[0019] The base station device 101 transmits configuration information for the terminal device 102 (S302). In one example, the base station device 101 determines in advance a predetermined number indicating the number of beams to be disabled (and enabled) and notifies the terminal device 102 of the configuration information. This configuration information may be notified to the terminal device 102 together with general configuration information such as a measurement report, or may be notified to the terminal device 102 when the terminal device 102 initiates a beam activation process. The predetermined number may also be determined by the terminal device 102, in which case the process of S302 may be omitted. Thereafter, the base station device 101 transmits a reference signal in each of the many beams 111. The terminal device 102 observes the reference signal for each of the enabled first beams 112 and each of the second beams that are at least a part of the non-enabled beams, and acquires radio quality (S303).

[0020] Based on the wireless quality, the terminal device 102 determines a predetermined number of third beams to be disabled from among the currently enabled first beams 112, and determines a fourth beam to be enabled from among the second beams that are not currently enabled (S304). For example, when the base station device 101 notifies the terminal device 102 of the predetermined number, the terminal device 102 identifies the predetermined number (e.g., "one") of the enabled first beams 112 in descending order of wireless quality as the third beams. Furthermore, the terminal device 102 extracts a predetermined number of beams or less in descending order of wireless quality from among the second beams that are not included in the first beams 112 and that have been measured, and identifies these beams as the fourth beams. Note that if the number of enabled beams does not reach an upper limit, such as eight, a number of beams exceeding the predetermined number may be identified as the fourth beams. Then, the terminal device 102 transmits to the base station device 101 a report specifying the extracted third beam and fourth beam, the report specifying the purpose of disabling the third beam and enabling the fourth beam (S305). As a result, the enabled first beam 112 among the multiple beams 111 is updated between the base station device 101 and the terminal device 102. That is, the set of beams obtained by removing the third beam from the first beam 112 used before the time of S305 and adding the fourth beam becomes the updated first beam 112. Note that, if the base station device 101 successfully receives the report from the terminal device 102, it may transmit an acknowledgement (HARQ-ACK) to the terminal device 102. At this point, the updating of the first beam 112 is completed, and the base station device 101 selects a beam to be used in subsequent communications from the updated first beam 112 and transmits information specifying the selected beam in DCI (S306). Then, communication is carried out between the base station device 101 and the terminal device 102 using the designated beam (S307).

[0021] Here, the update of the first beam 112 will be described using Figures 4A to 4C. Figure 4A shows an example of the first beam 112 set in the period up to S304, for example. The first beam 112 is a group of eight enabled beams, each of which is assigned a different codepoint value to enable specification by DCI. In the example of Figure 4A, the base station device 101 is configured to be able to form a large number of beams 111, such as beam #1 to beam #64, of which beam #1, beam #5, beam #16, beam #17, beam #32, beam #43, beam #52, and beam #53 are enabled as the first beam 112, and are assigned codepoints = 1 to 8. In this state, the terminal device 102 transmits a report to the base station device 101, specifying beams #1, #32, and #43 as third beams and beams #8, #14, and #49 as fourth beams, as shown in FIG. 4B . Here, the list of third beams and the list of fourth beams are concatenated, and information on six beams can be reported. If the base station device 101 recognizes the predetermined number, it can identify whether each of the six beams is a third beam or a fourth beam. That is, in the example of FIG. 4B , since the predetermined number is "3," the base station device 101 can identify that the first three beams are third beams and the other beams are fourth beams. Note that, although the example of FIG. 4B shows a case where the fourth beam is listed after the third beam, the fourth beam may be listed first. Furthermore, the base station device 101 may, for example, compare the beam identification information with the identification information of the beam included in the first beam 112, and identify that the beam included in the first beam 112 among the reported beams is the third beam. The third beam may also be specified using a codepoint value. That is, in the examples of FIGS. 4A and 4B, codepoints = 1, 5, and 6 may be notified as information indicating the third beam. In this way, the base station device 101 identifies the third beam and the fourth beam from the received report. Then, for example, the third beam and the fourth beam are swapped in the order in which they were reported.That is, in the example of FIG. 4B , the third beam is specified in the order of beam #1, beam #32, and beam #43, and the fourth beam is specified in the order of beam #8, beam #14, and beam #49. Therefore, beam #1 is swapped with beam #8, beam #32 with beam #14, and beam #43 with beam #49. For beams other than the third beam among the first beams 112, the correspondence with the codepoints can be maintained. This makes it possible to obtain an updated first beam 112 as shown in FIG. 4C . Note that this is just an example, and each time an update is performed, the codepoint values ​​may be reassigned by sorting in the order of the beam identification information. Note that the rule for changing the correspondence between codepoints and beams is shared between the base station device 101 and the terminal device 102. As a result, the base station device 101 and the terminal device 102 always share knowledge of the beams included in the first beam 112 and the correspondence between these beams and codepoints.

[0022] The terminal device 102 may transmit the report of S305, for example, on the condition that the wireless quality of a predetermined number of beams notified by the base station device 101 or a predetermined number of beams among the configured first beams 112 falls below a predetermined level. That is, for example, if the wireless quality of all of the first beams 112 exceeds a predetermined level, there is no need to update the first beam 112, and therefore the above-mentioned report may not be made. For example, if the predetermined number is "3," the terminal device 102 may transmit the report of S305 in response to the number of beams among the first beams 112 whose wireless quality as a measurement result falls below a predetermined level. Note that a condition similar to a measurement report event may be set as this condition. For example, in addition to the radio quality of a predetermined number of beams included in the first beam 112 being below a predetermined level, other conditions may be set, such as the radio quality of one or more beams among the second beams exceeding a second predetermined level, or there being one or more beams among the second beams having better radio quality than the predetermined number of beams included in the first beam 112.

[0023] Furthermore, the terminal device 102 may determine the number of beams to be reported to the base station device 101 as third beams from among the configured first beams 112 without receiving an instruction from the base station device 101. In this case, the terminal device 102 may transmit information that enables distinction between the third beams and the fourth beams, by including it in the report. For example, the terminal device 102 may transmit information that indicates the number of third beams (i.e., the above-mentioned predetermined number), by including it in the report. In this way, when the base station device 101 receives a list in which a list of third beams and a list of fourth beams are linked, it becomes possible to identify whether each beam included in the list is a third beam or a fourth beam. Note that, as described above, the base station device 101 may identify whether each reported beam is included in the current first beam 112 based on beam identification information. Furthermore, the third beam may be notified by a codepoint value. In this way, the base station device 101 can distinguish between the third beam and the fourth beam in various ways, and the terminal device 102 can generate a report corresponding to which method of sending the report will be used and transmit the report to the base station device 101.

[0024] Furthermore, the terminal device 102 may report only the fourth beam to be added to the base station device 101. In this case, the base station device 101 may determine third beams, the number of which is equal to or greater than the number of fourth beams, based on, for example, radio quality. That is, the base station device 101 may determine the third beam rather than the terminal device 102. In this case, for example, the base station device 101 may transmit information indicating the third beam to the terminal device 102, for example, by DCI. Alternatively, the terminal device 102 may determine the third beam, and the base station device 101 may determine the fourth beam. In this case as well, the base station device 101 may transmit information indicating the fourth beam to the terminal device 102, for example, by DCI.

[0025] In this way, in this embodiment, the terminal device 102 can determine a beam to be activated from among the multiple beams 111 formed by the base station device 101. This makes it possible to timely activate and use a beam that is appropriate for the situation in which the terminal device 102 is placed. Note that even when the terminal device 102 initially sets the first beam 112 after connecting to the base station device 101, the terminal device 102 may determine a beam to be activated and report it to the base station device 101.

[0026] In the above example, an example was described in which the terminal device 102 independently updates the first beam 112. This allows a beam suitable for the communication of the terminal device 102 to be selected and activated, thereby enabling high-quality communication of the terminal device 102. On the other hand, in order for the base station device 101 to adjust communications with all of the terminal devices subordinate thereto, it may be more appropriate for the base station device 101 to determine the beam to be activated. Therefore, in another example of this embodiment, the base station device 101 notifies the beam to be activated / deactivated by DCI, thereby shortening the time required for processing to activate / deactivate the beam. This processing will be described using FIG. 5. Note that in FIG. 5, processing similar to that in FIG. 3 is assigned the same reference numerals, and description thereof will be omitted.

[0027] Based on the wireless quality measured in S303, the terminal device 102 transmits a predetermined notification to the base station device 101 indicating that the activated beam should be changed (S501). This predetermined notification may include, for example, information requesting the base station device 101 to update the first beam 112. This predetermined notification may also include measurement results for the activated first beam 112 and second beams, which are at least some of the non-activated beams for which wireless quality measurements have been performed. In this case, based on the measurement results, the base station device 101 selects a third beam to be deleted from the first beams 112 and a fourth beam to be activated from the second beams. The base station device 101 may then update the first beam 112 by deleting the third beam from the first beams 112 and adding the fourth beam. In one example, the base station device 101 may select a predetermined number of beams from the first beams 112 in ascending order of wireless quality as third beams, and select a predetermined number or less of beams from the second beams in ascending order of wireless quality as fourth beams. Note that if the number of enabled beams does not reach an upper limit, such as eight, a number of beams exceeding the predetermined number may be selected as fourth beams. Note that this is merely an example, and the base station device 101 may, for example, preferentially select a beam whose frequency of use within a certain period is below a predetermined value as the third beam to be disabled. Furthermore, the base station device 101 may, for example, select a beam whose wireless quality is relatively low in relation to beams used for communication with other terminal devices as the fourth beam. In this way, the base station device 101 may select a beam to be enabled or disabled taking into consideration factors other than wireless quality. Furthermore, the above-mentioned predetermined notification may include information indicating which of the first beams should be selected as the third beam. The base station device 101 may then determine the beam indicated by the predetermined notification as the third beam. In this case, the base station device 101 may select from the second beams a number of beams equal to or less than the number of beams indicated by the predetermined notification and determine them as the fourth beams.That is, the third beam may be designated by the terminal device 102, and the fourth beam may be selected by the base station device 101. Furthermore, the above-mentioned predetermined notification may include information indicating which of the second beams should be selected as the fourth beam. That is, the base station device 101 may receive a predetermined notification designating both the third beam and the fourth beam from the terminal device 102, and approve the enabling / disabling of the beams indicated by the predetermined notification. In this case, the base station device 101 may refuse to enable / disable at least some of the designated beams. Furthermore, in this case, the base station device 101 may independently select the beams to be enabled / disabled instead.

[0028] As described above, the base station device 101 selects or determines a third beam and a fourth beam based on receiving a predetermined notification from the terminal device 102, and transmits DCI including first information (Activated Beams) indicating that the third beam and the fourth beam are to be designated and that the fourth beam is to be disabled and enabled, to the terminal device 102 (S502). In one example, the first information may designate the third beam by, for example, a bitmap (e.g., 8 bits) in which one bit corresponds to each of the first beams 112. For example, in the bitmap, beams to be deleted are set to "1" and beams that should not be deleted are set to "0", or the former are set to "0" and the latter are set to "1". Note that this is just an example, and information in another format may be used. At this time, the base station device 101 may also transmit second information (Beam Indication) that specifies the beam to be used in communication using the frequency / time resources specified by the DCI, by including it in the DCI.

[0029] Upon receiving the DCI, the terminal device 102 deletes the third beam from the information on the first beam 112 it holds, adds the fourth beam, and updates the first beam 112. When the base station device 101 receives a predetermined notification from the terminal device 102 including a designation of the third beam or the fourth beam, the base station device 101 may include, in the DCI, one-bit information indicating whether or not to accept the designation. When the designation is accepted, the terminal device 102 deletes the third beam designated in the predetermined notification from the first beam 112. When the terminal device 102 designates the fourth beam in the predetermined notification and the designation is accepted by the base station device 101, the terminal device 102 adds the fourth beam to the first beam 112. The base station device 101 may transmit a DCI including information indicating that only either the third beam or the fourth beam has been accepted, and information designating an independently selected beam for the other beam. In this case, if the third beam is accepted, the terminal device 102 deletes the third beam specified in the predetermined notification from the first beam 112, and adds the fourth beam specified by the base station device 101 to the first beam 112. Furthermore, if the fourth beam is accepted, the terminal device 102 adds the fourth beam specified in the predetermined notification to the first beam 112, and deletes the beam specified by the base station device 101 from the first beam 112. Furthermore, the base station device 101 may be notified of information indicating that the first beam 112 should be maintained without being updated. In this way, the first beam 112 is updated between the base station device 101 and the terminal device 102. Then, the terminal device 102 communicates with the base station device 101 using configuration information for when the beam specified by the above-mentioned second information is used in the base station device 101 from the updated first beam 112 (S307).

[0030] 5, in response to receiving a predetermined notification, the base station device 101 updates the first beam 112 and notifies the terminal device 102 of the information by DCI. At this time, the base station device 101 updates the beam that is enabled by signaling of the physical (PHY) layer, rather than updating the beam that is enabled by signaling of the RRC layer or MAC layer as in the conventional case. This enables high-speed switching of the enabled beam, making it possible to timely enable and use a beam that is suitable for the situation in which the terminal device 102 is placed.

[0031] FIG. 6 shows an example of the hardware configuration of the base station device 101 and the terminal device 102 according to this embodiment. In one example, the base station device 101 and the terminal device 102 are configured to include a processor 601, a ROM 602, a RAM 603, a storage device 604, and a communication circuit 605. The processor 601 is a computer configured to include one or more processing circuits, such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit), and performs the overall processing of the device and each of the above-mentioned processes by reading and executing programs stored in the ROM 602 or the storage device 604. The ROM 602 is a read-only memory that stores information such as programs and various parameters related to the processing executed by the base station device 101 and the terminal device 102. The RAM 603 functions as a workspace when the processor 601 executes a program and is also a random access memory that stores temporary information. The storage device 604 is configured, for example, by a removable external storage device. The communication circuit 605 is configured, for example, by a circuit for wireless communication of 5G or a successor standard. Although one communication circuit 605 is illustrated in FIG. 6 , the base station device 101 and the terminal device 102 may have multiple communication circuits. For example, the base station device 101 and the terminal device 102 may have wireless communication circuits for 5G and a successor standard, respectively, and a common antenna for these circuits. The base station device 101 and the terminal device 102 may also have separate antennas suitable for each standard. The base station device 101 may also have a wired communication circuit used when communicating with other base station devices or nodes in the core network. The terminal device 102 may also have a communication circuit compliant with a wireless communication standard other than a cellular communication standard, such as a wireless local area network (LAN) or Bluetooth (registered trademark). The base station device 101 and the terminal device 102 may have separate communication circuits 605 for each of the multiple available frequency bands, or may have a common communication circuit 605 for at least some of the frequency bands.

[0032] FIG. 7 shows an example of the functional configuration of the terminal device 102. The terminal device 102 includes, for example, a measurement unit 701, a setting reception unit 702, an effective beam update unit 703, an information notification unit 704, and a communication unit 705. Note that FIG. 7 only shows functions particularly related to this embodiment, and various other functions that the terminal device 102 may have are omitted from the illustration. For example, the terminal device 102 naturally has other functions that terminal devices compliant with 5G or subsequent standards generally have. The functional blocks in FIG. 7 are shown schematically, and the respective functional blocks may be integrated or further subdivided. Furthermore, each function in FIG. 7 may be realized, for example, by the processor 601 executing a program stored in the ROM 602 or the storage device 604, or may be realized, for example, by a processor within the communication circuit 605 executing predetermined software. Since the details of the processing performed by each functional unit are as described above, only the general functions of the terminal device 102 will be outlined here.

[0033] The measurement unit 701 measures radio quality by observing reference signals transmitted from a first beam 112 and a second beam, which is at least a portion of the beams not included in the first beam 112, among the multiple beams 111 formed in the base station device 101. The setting receiver 702 receives various setting information from the base station device 101. For example, when the terminal device 102 takes the initiative in updating the first beam 112, the setting receiver 702 can receive setting information such as the predetermined number of pieces of information described above. When the terminal device 102 takes the initiative in updating the first beam 112, the effective beam update unit 703 determines the third beam and fourth beam described above based on the measurement results by the measurement unit 701, and updates the first beam 112 by deleting the third beam from the first beam 112 and adding the fourth beam. In addition, when the effective beam update unit 703 receives information specifying the third beam and the fourth beam from the base station device 101, it deletes the specified third beam from the first beam 112 that it holds and adds the fourth beam to the first beam 112.

[0034] When the first beam 112 is updated under the initiative of the terminal device 102, the information notification unit 704 transmits to the base station device 101 a report specifying the third beam and the fourth beam determined by the terminal device 102. When the base station device 101 determines the third beam and the fourth beam, the information notification unit 704 transmits to the base station device 101 a predetermined notification including a request to update the first beam 112 and information specifying at least the third beam and, in some cases, also the fourth beam. When the base station device 101 updates the first beam 112 under the initiative of the base station device 101, the information notification unit 704 may notify the base station device 101 of measurement results of the wireless quality for each of the first beam 112 and each of the second beam. Note that the information notification unit 704 may, for example, associate wireless quality information with beam identification information and notify the base station device 101 only for beams whose wireless quality exceeds a predetermined level. Furthermore, the information notification unit 704 may notify the base station device 101 of the wireless quality only for each of the third beam and the fourth beam, or may additionally notify the base station device 101 of the wireless quality and beam identification information for some beams, such as beams for which a predetermined level of wireless quality has been obtained, rather than for all beams. Furthermore, the information notification unit 704 may notify the base station device 101 of capability information indicating whether or not the terminal device 102 supports each of the processes described in this embodiment, for example.

[0035] The communication unit 705 communicates with the base station device 101 using settings corresponding to any one of the first beams 112 updated by the valid beam update unit 703 (or notified to the base station device 101 by the information notification unit 704, when the terminal device 102 takes the initiative in updating the first beam 112). The communication unit 705 receives DCI from the base station device 101 specifying which of the first beams 112 to use, and communicates with the base station device 101 using settings corresponding to the specified beam. Note that the terminal device 102, for example, receives information on reference signals transmitted from each of the multiple beams 111 in advance from the base station device 101, and can measure the reference signals transmitted from each beam based on the information and prepare and store reception settings corresponding to each beam in advance. The communication unit 705 can then receive downlink signals transmitted from the base station device 101 using the reception settings for the beam specified in the DCI. Furthermore, the terminal device 102 can transmit a reference signal (e.g., a sounding reference signal (SRS)) using, for example, multiple beams that the terminal device can form, and can store in advance configuration information based on measurement results of the reference signal in the base station device 101. For example, when communication is performed using each of a large number of beams 111 according to the measurement results, the base station device 101 can determine the configuration to be used for signal transmission by the terminal device 102 and notify the terminal device 102 of the configuration information in advance. The terminal device 102 then receives and stores the configuration information, and the communication unit 705 can extract the configuration information corresponding to the beam specified in the DCI and transmit a signal using the configuration information.

[0036] FIG. 8 shows an example of the functional configuration of the base station device 101. The base station device 101 includes, for example, a reference signal transmitter 801, a setting notification unit 802, a report receiver 803, an effective beam update unit 804, and a communication unit 805. Note that FIG. 8 only shows functions particularly related to this embodiment, and various other functions that the base station device 101 may have are omitted from the illustration. For example, the base station device 101 naturally has other functions that are generally possessed by base station devices compliant with 5G and subsequent standards. The functional blocks in FIG. 8 are shown schematically, and each functional block may be realized by being integrated or further subdivided. Furthermore, each function in FIG. 8 may be realized, for example, by the processor 601 executing a program stored in the ROM 602 or the storage device 604, or by a processor within the communication circuit 605 executing predetermined software. Since the details of the processing performed by each functional unit are as described above, only the general functions of the base station device 101 will be outlined here.

[0037] The reference signal transmitting unit 801 transmits reference signals (e.g., CSI-RS or SSB) using each of the multiple beams 111. The setting notifying unit 802 notifies the terminal device 102 of various setting information, such as settings for executing the above-mentioned processing. The report receiving unit 803 receives from the terminal device 102, for example, a report specifying the third beam and the fourth beam when the terminal device 102 takes the initiative in updating the first beam 112, and receives the above-mentioned predetermined notification when the base station device 101 takes the initiative in updating the first beam 112.

[0038] When the terminal device 102 takes the initiative in updating the first beam 112, the effective beam updating unit 804 deletes the third beam specified by the report from the first beam 112 and adds the fourth beam to the first beam 112. Also, when the base station device 101 takes the initiative in updating the first beam 112, the effective beam updating unit 804 selects the third beam and the fourth beam. Note that, for example, when the terminal device 102 specifies the third beam, the effective beam updating unit 804 can determine whether or not to agree to deleting the third beam from the first beam 112. Also, when the terminal device 102 specifies the fourth beam, the effective beam updating unit 804 can determine whether or not to agree to add the fourth beam to the first beam 112. In addition, when the valid beam update unit 804 does not receive a designation of a third beam or a fourth beam from the terminal device 102 or when it rejects such a designation, it independently selects a third beam to be deleted from the first beam 112 and a fourth beam to be added to the first beam 112. For example, the valid beam update unit 804 may determine the frequency with which each beam included in the first beam 112 was actually used during a predetermined period, and identify a beam with a lower frequency (for example, lower than a predetermined value) as the third beam. The valid beam update unit 804 may also identify a predetermined number of beams with the lowest frequency as the third beam. Furthermore, when the terminal device 102 notifies the valid beam update unit 804 of the wireless quality of each of the first beams 112, the valid beam update unit 804 may identify a beam with a wireless quality lower than a predetermined value as the third beam. Furthermore, the valid beam update unit 804 may also identify a predetermined number of beams with the lowest wireless quality as the third beam. Furthermore, the effective beam updating unit 804 selects fourth beams that are equal to or less than the number of beams selected as the third beams. For example, the effective beam updating unit 804 may determine as the fourth beams a beam that is equal to or less than the number of the third beams and that has the best wireless quality notified by the terminal device 102. Furthermore, the effective beam updating unit 804 may, for example, preferentially select as the fourth beam a beam that is not being used in communications with other terminal devices.In addition, if the number of beams included in the first beam 112 does not reach the maximum number that can be included in the first beam 112, the effective beam update unit 804 may select a number of fourth beams that exceeds the number of third beams, as long as the number does not exceed the maximum number of first beams 112.

[0039] The communication unit 805 determines a beam to be used for communication with the terminal device 102 from the updated first beams 112, and notifies the terminal device 102 using DCI that communication will be performed using that beam. Then, the communication unit 805 communicates with the terminal device 102 using the communication setting corresponding to that beam.

[0040] As described above, in this embodiment, it is possible to quickly update the first beam 112, which is enabled for use between the base station device 101 and the terminal device 102, among the multiple beams 111 formed by the base station device 101. This makes it possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, which is to "build resilient infrastructure, promote sustainable industrialization, and foster innovation."

[0041] This application claims priority based on Japanese Patent Application No. 2024-049212, filed March 26, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A terminal device comprising: a measurement means for measuring wireless quality of signals transmitted from each of a plurality of first beams, among a plurality of beams formed by a base station device currently connected, that are enabled for communication between the base station device and the terminal device, and each of a plurality of second beams that are at least a portion of the beams not included in the first beams; a transmission means for transmitting a predetermined notification to the base station device based on the results of the wireless quality measurement; a reception means for receiving from the base station device, based on the predetermined notification, downlink control information (DCI) including first information indicating that a third beam is designated from among the first beams and a fourth beam is designated from among the second beams, thereby disabling the third beam and enabling the fourth beam, and second information specifying a beam to be used by the base station device in communication between the base station device and the terminal device; an update means for updating the first beam by removing the third beam from the first beams and adding the fourth beam; and a communication means for communicating with the base station device using settings corresponding to the beam designated by the second information from the updated first beams.

2. The terminal device according to claim 1, wherein the predetermined notification includes information requesting the base station device to update the first beam.

3. The terminal device according to claim 2, wherein the predetermined notification includes the result of the measurement for at least one of the first beam and the second beam.

4. The terminal device according to claim 2, wherein the predetermined notification includes information indicating which of the first beams should be the third beam.

5. The terminal device according to claim 4, wherein the predetermined notification includes information indicating which of the second beams should be the fourth beam.

6. A base station device comprising: a transmitting means for forming a plurality of beams including a plurality of first beams enabled for communication between the base station device and a terminal device and transmitting signals; a receiving means for receiving from the terminal device a predetermined notification based on a result of measuring the radio quality of signals transmitted from each of the first beams and each of second beams that are at least a portion of the beams not included in the first beams among the plurality of beams; a notifying means for notifying the terminal device, based on the predetermined notification, using downlink control information (DCI), of first information indicating that a third beam is designated from among the first beams and a fourth beam is designated from among the second beams, the third beam is disabled, and the fourth beam is enabled, and second information specifying a beam to be used by the base station device in communication between the base station device and the terminal device; and a communication means for communicating with the terminal device using settings corresponding to the beam designated by the second information from among the first beams updated by removing the third beam from the first beams and adding the fourth beam.

7. The base station device according to claim 6, wherein the predetermined notification includes information requesting the base station device to update the first beam.

8. The base station device of claim 7, wherein the predetermined notification includes a result of measuring the radio quality for at least one of the first beam and the second beam, and the base station device further has a selection means for selecting the third beam and the fourth beam based on the result of the measurement.

9. The base station device according to claim 8, wherein the selection means selects a predetermined number of beams from the first beams in descending order of the radio quality as the third beams, and selects beams from the second beams that are equal to or less than the predetermined number as the fourth beams.

10. A base station device as described in claim 6, wherein the predetermined notification includes information indicating which of the first beams should be the third beam, and the notification means notifies the terminal device of the first information specifying the beam indicated by the predetermined notification as the third beam.

11. A base station device as described in claim 10, further comprising a selection means for selecting the fourth beams from among the second beams, the number of which is equal to or less than the number of beams indicated by the predetermined notification, and the notification means notifies the terminal device of the first information specifying the fourth beams selected by the selection means.

12. The base station device according to claim 10, wherein the predetermined notification further includes information indicating which of the second beams should be the fourth beam, and the notification means notifies the terminal device of the first information specifying the beam to be the fourth beam indicated by the predetermined notification as the fourth beam.

13. A control method executed by a terminal device, comprising: measuring wireless quality of signals transmitted from each of a plurality of first beams, among a plurality of beams formed by a connected base station device, that are enabled for communication between the base station device and the terminal device, and each of a plurality of second beams that are at least a portion of the beams not included in the first beams; transmitting a predetermined notification to the base station device based on the results of the wireless quality measurement; receiving downlink control information (DCI) from the base station device based on the predetermined notification, the DCI including first information indicating that a third beam is designated from among the first beams and a fourth beam is designated from among the second beams, the third beam is disabled, and the fourth beam is enabled, and second information specifying a beam to be used by the base station device in communication between the base station device and the terminal device; updating the first beam by removing the third beam from the first beams and adding the fourth beam; and communicating with the base station device using settings corresponding to the beam designated by the second information from among the updated first beams.

14. A control method executed by a base station device, comprising: forming a plurality of beams including a plurality of first beams enabled for communication between the base station device and a terminal device and transmitting signals; receiving from the terminal device a predetermined notification based on results of measuring the radio quality of signals transmitted from each of the first beams and each of second beams that are at least a portion of the beams not included in the first beams among the plurality of beams; notifying the terminal device, based on the predetermined notification, using downlink control information (DCI), of first information indicating that a third beam is designated from among the first beams and a fourth beam is designated from among the second beams, the third beam is disabled, and the fourth beam is enabled, and second information specifying a beam to be used by the base station device in communication between the base station device and the terminal device; and communicating with the terminal device using settings corresponding to the beam designated by the second information from among the first beams updated by removing the third beam from the first beams and adding the fourth beam.

15. A program for causing a computer installed in a terminal device to execute the control method according to claim 13.

16. A program for causing a computer installed in a base station device to execute the control method set forth in claim 14.

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