Terminal device, base station device, control method, and program for highly accurate measurement of sounding reference signal

Abstract

To allow appropriate communication control to be executed for a terminal device having a large number of antennas.SOLUTION: A terminal device having a plurality of antennas obtains a first configuration related to a sounding reference signal (SRS) for a first group including four or fewer antennas among the plurality of antennas and a second configuration related to the SRS that is different from the first configuration for a second group including four or fewer antennas that do not belong to the first group among the plurality of antennas, and transmits the SRS using the first configuration on the antennas belonging to the first group, and transmits the SRS using the second configuration on the antennas belonging to the second group. The second configuration includes a configuration that specifies that the SRS is transmitted using a different resource element from the first configuration.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control technique for transmitting reference signals by a terminal device having multiple antennas. [Background technology]

[0002] The Third Generation Partnership Project (3GPP) specifies that a terminal device transmits a sounding reference signal (SRS) to a base station device. Based on the observation results of the SRS, the terminal device can perform beam setting control when transmitting an uplink signal. Note that SRS transmission setting is performed for each terminal device, and the terminal device notifies the base station device of the number of antennas it has, and the base station device notifies the terminal device of the SRS setting corresponding to the number of antennas. Summary of the Invention [Problem to be solved by the invention]

[0003] Conventionally, SRS settings can only support up to four antennas. However, as terminal devices become more sophisticated, it is expected that the number of antennas will increase to five or more. Therefore, it is not possible to properly control communications based on SRS for terminal devices with five or more antennas. [Means for solving the problem]

[0004] The present invention provides a technique that enables appropriate communication control for a terminal device having multiple antennas.

[0005] A terminal device according to one aspect of the present invention is a terminal device having a plurality of antennas, a grouping means for allocating the plurality of antennas to a plurality of groups including a first group and a second group, the grouping means including: four or fewer antennas of the plurality of antennas a grouping unit that assigns four or less antennas of the plurality of antennas that are not assigned to the first group to the second group; a notification unit that notifies a base station device of information specifying the antennas that are assigned to each of the plurality of groups by the grouping unit; and a notification unit that notifies a base station device of information specifying the antennas that are assigned to the first group based on the notification. a first setting for a sounding reference signal (SRS) for The aforementioned a second setting for the SRS different from the first setting for the second group; The setting regarding the SRS for each of the plurality of groups including And, The second setting isA configuration specifying that the SRS is transmitted using a resource element different from that of the first configuration is included. The above settings of, The aforementioned The SRS transmission device includes an acquisition means for acquiring the SRS from a base station device, and a transmission means for transmitting the SRS using the first setting from an antenna belonging to the first group and using the second setting from an antenna belonging to the second group.

[0006] A base station device according to one aspect of the present invention comprises: Information specifying antennas assigned to a plurality of groups by a terminal device, the information specifying the antennas assigned to a plurality of groups by the terminal device No more than four antennas but First group and acquiring the information indicating that four or less antennas not assigned to the first group among the plurality of antennas are assigned to a second group; A first setting for a sounding reference signal (SRS) for a first group and a previous setting for a second group. Note a second setting for the SRS different from the first setting for the second group; The setting regarding the SRS for each of the plurality of groups including And, The second setting is A configuration specifying that the SRS is transmitted using a resource element different from that of the first configuration is included. The above settings a notification means for notifying the terminal device of the SRS transmitted by the antennas belonging to the first group using the first setting, and a measurement means for measuring the SRS transmitted by the antennas belonging to the second group using the second setting. [Effects of the Invention]

[0007] According to the present invention, it is possible to perform appropriate communication control for a terminal device having multiple antennas. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 illustrates an example of a system configuration. [Figure 2] FIG. 2 illustrates an example of a hardware configuration of the apparatus. [Figure 3] FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal device. [Figure 4] FIG. 2 is a diagram illustrating an example of a functional configuration of a base station device. [Figure 5]FIG. 10 is a diagram illustrating an example of a flow of processing executed in the system. [Figure 6] FIG. 10 is a diagram illustrating an example of a flow of processing executed in the system. [Figure 7] FIG. 10 is a diagram illustrating an example of a flow of processing executed in the system. DETAILED DESCRIPTION OF THE INVENTION

[0009] 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.

[0010] (System Configuration) FIG. 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) wireless communication standard of the 3rd Generation Partnership Project (3GPP). Note that this is just one example, and the system may be, for example, a Long Term Evolution (LTE) or 5G or later cellular communication system, or a wireless communication system other than a cellular system. This wireless communication system includes, for example, a base station device 101 and a terminal device 111. Note that, for simplicity of explanation, only one base station device 101 and one terminal device 111 are shown in FIG. 1, but naturally, there may be many base station devices and many terminal devices.

[0011] In this embodiment, the terminal device 111 has multiple antennas. Fig. 1 shows an example in which the terminal device 111 has eight antennas 121 to 128. Naturally, the base station device 101 may also have multiple antennas, but this is not relevant to this embodiment and is not shown in Fig. 1. Furthermore, although the term "antenna" is used below, this term may also be read as "antenna port."

[0012] The terminal device 111 transmits a sounding reference signal (SRS) using each of multiple antennas. The base station device 101 notifies the terminal device 111 of settings for transmitting the SRS and measures the subsequently transmitted SRS using the settings. The settings may include, for example, information specifying which resource element to use to transmit the SRS. Note that a resource element is a radio resource equivalent to one subcarrier having a predetermined frequency bandwidth and one OFDM (Orthogonal Frequency Division Multiplexing) symbol having a predetermined time width. The base station device 101 may then perform transmission channel estimation between the multiple antennas of the terminal device 111 and its own antenna based on, for example, the measurement results, and determine the settings of a beam to be used by the terminal device 111 in the uplink. By notifying the terminal device 111 of the beam settings, the base station device 101 can perform uplink communications efficiently. Note that the SRS may be used not only for uplink beamforming but also for, for example, antenna switching and positioning based on uplink signals.

[0013] A single piece of setting information for the SRS setting is notified to the terminal device 111. The terminal device 111 notifies the base station device 101 of the number of antennas, and the base station device 101 determines the SRS setting according to that number. A single piece of SRS setting information notifies the terminal device 111 of the SRS setting for up to four antennas. At this time, the resource elements for transmitting the SRS specified by the SRS setting information are common, and up to four antennas transmit the SRS using the same resource elements. Note that the symbol sequence transmitted from up to four antennas is a single symbol sequence that has been phase-shifted, and the SRS transmitted from up to four antennas using the same resource elements is multiplexed depending on the amount of phase shift.

[0014] Here, when considering an SRS setting method when the number of antennas included in the terminal device 111 is more than four as shown in Fig. 1, the simplest approach would be to apply a phase shift amount different from the phase shift amount applied to each of the four antennas to the fifth and subsequent antennas. However, in this case, it is possible that the accuracy of channel estimation in the base station device 101 cannot be sufficiently improved due to the large number of multiplexed sequences, which makes accurate separation impossible in the base station device 101, and the transmission power of the SRS per antenna is limited by transmitting SRS simultaneously using the same resource element from multiple antennas.

[0015] In this embodiment, in consideration of such circumstances, when the terminal device 111 has more than four antennas, the base station device 101 may notify the terminal device 111 of multiple SRS configurations. For example, the base station device 101 may generate a first SRS configuration for antennas 121 to 124 of the terminal device 111's antennas 121 to 128 and a second SRS configuration for antennas 125 to 128, and notify the terminal device 111 of these configurations. At this time, different resource elements are configured to be used among the multiple configurations. This prevents SRS from being transmitted using the same resource elements for, for example, five or more antennas. This facilitates separation in the base station device 101 compared to when multiplexing is performed using the amount of phase shift, enabling highly accurate channel estimation. Furthermore, it may be specified that different resource elements in the time domain should be used for SRS transmission in each of the multiple configurations. This makes it possible to limit the number of SRSs transmitted in the same time resource, thereby ensuring that the power of the SRSs transmitted from each antenna is sufficiently high, and enabling the base station device 101 to perform highly accurate transmission path estimation.

[0016] Note that, by limiting the number of antennas associated with one setting to four or less, conventional SRS settings can be reused, but one setting may also be configured for a predetermined number of antennas equal to or greater than five. In this case, for terminal device 111 having more than the predetermined number of antennas, the smallest integer equal to or greater than the result of dividing the total number of antennas by the predetermined number is identified, and that integer number of settings can be applied to terminal device 111. For example, if the predetermined number is five, a first setting for antennas 121 to 125 and a second setting for antennas 126 to 128 can be notified to terminal device 111 and applied.

[0017] As described above, in this embodiment, the multiple antennas possessed by the terminal device 111 are grouped into multiple groups, each including a predetermined number (for example, four) or less of antennas, and a separate SRS configuration for each of the multiple groups is notified to the terminal device 111 from the base station device 101. The terminal device 111 then transmits SRS from each of the multiple antennas by applying the configuration for the group to which the antenna belongs. That is, for example, if the terminal device 111 acquires a first SRS configuration for the antennas 121 to 124 and a second SRS configuration for the antennas 125 to 128, the terminal device 111 transmits SRS from the antennas 121 to 124 using the first configuration and from the antennas 125 to 128 using the second configuration. The base station device 101 measures the SRS transmitted from each of the antennas 121 to 124 based on the first configuration, and measures the SRS transmitted from each of the antennas 125 to 128 based on the second configuration. According to this, when the terminal device 111 has five or more antennas, it is possible to ensure a sufficiently high accuracy of the channel estimation using the SRS transmitted from each of the five or more antennas.

[0018] The grouping of the multiple antennas that the terminal device 111 has may be performed by the terminal device 111 or by the base station device 101.

[0019] A case where the terminal device 111 groups antennas will be described. The terminal device 111 groups antennas based on the number of antennas the terminal device 111 has. For example, when SRS configuration for a maximum of four antennas is performed in one configuration as in the conventional case, the terminal device 111 determines ceil(N / 4) as the number of groups, where N is the number of antennas the terminal device 111 has. Note that ceil(x) is a ceiling function, which is a variable that returns the smallest integer greater than the argument x. In one example, when the terminal device 111 has eight antennas, ceil(8 / 4)=2, so it is decided to allocate antennas to two groups. Furthermore, when the terminal device 111 has ten antennas, ceil(10 / 4)=3, so it is decided to allocate antennas to three groups. When SRS is configured for a maximum of M antennas (for example, M>4) in one configuration, terminal device 111 determines ceil(N / M) as the number of groups, where N is the number of antennas owned by terminal device 111. Terminal device 111 then allocates the multiple antennas owned by itself to one of the multiple groups. As an example, terminal device 111 allocates eight antennas 121 to 128 to two groups: a first group including antennas 121 to 124, and a second group including antennas 125 to 128.

[0020] The terminal device 111 notifies the base station device 101 of information about the multiple groups obtained by grouping. Then, the base station device 101 acquires a notification including information about the multiple groups to which the terminal device 111 assigns multiple antennas, and determines an SRS configuration for each group based on the notification and notifies the terminal device 111. For example, the terminal device 111 may notify the base station device 101 that two groups will be formed, and the base station device 111 may determine a first SRS configuration for the first group and a second SRS configuration for the second group, and notify the terminal device 111 of the determined first and second configurations. The terminal device 111 may also notify the base station device 101 of the number of antennas assigned to each of the multiple groups as information about the multiple groups. Then, the base station device 101 may determine a configuration for each group depending on the number of antennas belonging to that group, and notify the terminal device 111 of multiple configurations corresponding to each of the multiple groups. Furthermore, the terminal device 111 may notify the base station device 101 of information capable of identifying an antenna assigned to each of the multiple groups as information about the multiple groups. The information capable of identifying an antenna may be, for example, a port number corresponding to the antenna. In this case, the base station device 101 may notify the terminal device 111 of setting information to be used when transmitting SRS from each antenna as setting related to each group.

[0021] Next, another process in which the terminal device 111 groups antennas will be described. The terminal device 111, for example, notifies the base station device 101 of the number of antennas it has. Then, based on the number of antennas, the base station device 101 determines the number of groups to which each of the antennas in the terminal device 111 will be assigned, and determines SRS configurations for that number. For example, if the terminal device 111 has eight antennas, the terminal device 111 notifies the base station device 101 of the number of antennas, "8." Here, if SRS configurations for a maximum of four antennas are performed in one configuration as in the conventional case, the base station device 101 determines that antennas will be assigned to two groups because ceil(8 / 4)=2. Then, the base station device 101 determines two SRS configurations corresponding to the two groups, and notifies the terminal device 111. Note that the base station device 101 may flexibly determine the number of antennas included in each SRS configuration, for example. For example, the base station device 101 may determine four SRS configurations, each corresponding to two antennas, and notify the terminal device 111. The base station device 101 may include information specifying the number of antennas corresponding to each configuration in the configuration and notify the terminal device 111. When the terminal device 111 receives multiple SRS configurations, it groups the number of antennas corresponding to the configuration as the antennas corresponding to the configuration. For example, when the terminal device 111 receives two SRS configurations, each corresponding to four antennas, it may group its antennas 121 to 128 into a first group to which antennas 121 to 124 belong and a second group to which antennas 125 to 128 belong. For example, when terminal device 111 receives setting information indicating that the first group has four antennas, the second group has two antennas, and the third group has two antennas, terminal device 111 can group antennas 121 to 128 into a first group to which antennas 121 to 124 belong, a second group to which antennas 125 and 126 belong, and a third group to which antennas 127 and 128 belong. Terminal device 111 then transmits SRS from each antenna based on the setting of the group to which that antenna belongs.In addition, the number of antennas in each group may be determined based on a predetermined rule, in which case the base station device 101 does not need to notify the terminal device 111 of information specifying the number of antennas corresponding to the setting of each group.

[0022] Next, a case where the base station device 101 groups antennas will be described. The terminal device 111 notifies the base station device 101 of information indicating the number of antennas the terminal device 111 has and information that allows each of the antennas to be identified. Note that the terminal device 111 may notify the base station device 101 of information that allows each of the antennas to be identified, but may not notify the base station device 101 of the information indicating the number of antennas. The base station device 101 groups the antennas based on the received information that allows the antennas to be identified. The base station device 101 may determine the group to which each antenna belongs based on any predetermined rule or randomly. For example, the base station device 101 may receive information that allows each of antennas 121 to 128 to be identified from the terminal device 111. Note that at this time, the base station device 101 may further receive information that indicates that the number of antennas owned by the terminal device 111 is eight. In this case, the base station device 101 may group the antennas 121 to 128 into two groups: a first group including the antennas 121 to 124, and a second group including the antennas 125 to 128. In another example, the base station device 101 may group the antennas 121 to 128 into three groups: a first group to which the antennas 121 to 124 belong, a second group to which the antennas 125 to 126 belong, and a third group to which the antennas 127 to 128 belong. The base station device 101 then determines the SRS configuration for each group, and notifies the terminal device 111 of information that can identify the antennas included in each group and the SRS configuration for that group, for each of the multiple groups. Based on the notification, the terminal device 111 identifies which group the multiple antennas belong to, and transmits SRS from each of the multiple antennas using the configuration of the corresponding group.

[0023] (Device configuration) Next, the configurations of the base station device 101 and the terminal device 111 that execute the above-described processes will be described. FIG. 2 is a diagram illustrating an example of the hardware configuration of the base station device 101 and the terminal device 111. In one example, the base station device 101 and the terminal device 111 are configured to include a processor 201, a ROM 202, a RAM 203, a storage device 204, and a communication circuit 205. The processor 201 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 executes the overall processing of the device and each of the above-described processes by reading and executing programs stored in the ROM 202 or the storage device 204. The ROM 202 is a read-only memory that stores information such as programs and various parameters related to the processes executed by the base station device 101 and the terminal device 111. The RAM 203 functions as a workspace when the processor 201 executes a program, and is also a random access memory that stores temporary information. The storage device 204 is configured, for example, by a removable external storage device. The communication circuit 205 is configured to include, for example, a circuit for communicating with other devices. Although one communication circuit 205 is illustrated in Fig. 2, the base station device 101 and the terminal device 111 may have multiple communication circuits. The terminal device 111 of this embodiment may be configured to include multiple antennas, and the multiple antennas may be connected to one communication circuit 205, or one or more of the multiple antennas may be connected to one communication circuit 205 and other antennas may be connected to another communication circuit 205.

[0024] FIG. 3 is a diagram illustrating an example of the functional configuration of the terminal device 111. The terminal device 111 includes, for example, an antenna information notification unit 301, a setting information acquisition unit 302, and an SRS transmission processing unit 303. The functions illustrated in FIG. 3 can be realized, for example, by the processor 201 executing a program stored in the ROM 202 or the storage device 204. Note that this is just one example, and some or all of the functions illustrated in FIG. 3 may be realized by dedicated hardware. Furthermore, FIG. 3 illustrates only functions related to the present embodiment among the functions possessed by the terminal device 111, and the terminal device 111 may naturally have functions other than those illustrated in FIG. 3, such as functions naturally possessed by a terminal device in a cellular communication system.

[0025] The antenna information notification unit 301 notifies the base station device 101 of information related to the multiple antennas of the terminal device 111. The setting information acquisition unit 302 receives, from the base station device 101, SRS setting information for each of multiple groups into which multiple antennas are grouped, in accordance with the information notified by the antenna information notification unit 301. The SRS transmission processing unit 303 applies, to each of the multiple antennas, the SRS setting related to the group to which that antenna belongs, based on the setting information acquired by the setting information acquisition unit 302, and transmits the SRS from each of the multiple antennas.

[0026] In one example, the antenna information notification unit 301 assigns multiple antennas of the terminal device 111 to multiple groups and notifies the base station device 101 of information about the multiple groups. Note that the information about the multiple groups may include additional information such as the total number of antennas, information indicating the number of antennas belonging to a group, and information that identifies the antennas belonging to a group. In this case, the setting information acquisition unit 302 acquires SRS setting information for each of the multiple groups from the base station device 101 based on the information about the multiple groups. Based on this setting information, the SRS transmission processing unit 303 applies the SRS setting for the group to which each antenna assigned to each group by the antenna information notification unit 301 belongs, and transmits the SRS. This setting information may be generated, for example, according to the number of antennas belonging to each group. Note that the number of antennas belonging to each group may be uniquely determined according to a predetermined rule based on the total number of antennas. In this case, the total number of antennas is notified to the base station device 101, so that the number of antennas belonging to each group does not need to be notified. Furthermore, when information that can identify antennas that belong to each group is notified, the total number of antennas or the number of antennas that belong to each group does not need to be notified. Note that when information that can identify antennas that belong to each group is notified, SRS setting information for each group, including individual settings for each antenna, may be notified to the terminal device 111. Furthermore, settings may be determined and notified on the assumption that each group includes the maximum number of antennas that can be configured with SRS, and in this case, it is sufficient that information that can identify the number of groups is notified to the base station device 101.

[0027] In another example, the antenna information notification unit 301 notifies the base station device 101 of the total number of antennas owned by the terminal device 111. Then, the setting information acquisition unit 302 acquires from the base station device 101 setting information for SRSs in a number corresponding to the number of groups to which the multiple antennas should be assigned by the base station device 101. The setting information here includes the number of antennas belonging to a group and the SRS settings to be used in that group. The SRS transmission processing unit 303 assigns the multiple antennas owned by the terminal device 111 to each group according to the number of antennas belonging to each group, and applies to each of the multiple antennas the SRS setting related to the group to which that antenna belongs. Then, the SRS transmission processing unit 303 transmits SRS from the multiple antennas using the settings applied to each of the multiple antennas.

[0028] In another example, the antenna information notification unit 301 notifies the base station device 101 of information capable of identifying each of the multiple antennas possessed by the terminal device 111 (and, if necessary, information on the total number of antennas). In this case, the multiple antennas are grouped by the base station device 101. The setting information acquisition unit 302 then acquires, from the base station device 101, setting information related to the SRS of the multiple groups and information indicating which of the multiple antennas is assigned to each of the multiple groups. Based on the acquired setting information, the SRS transmission processing unit 303 applies, to each of the antennas assigned to each group, the SRS setting related to the group to which that antenna belongs, and transmits the SRS.

[0029] FIG. 4 is a diagram illustrating an example of the functional configuration of the base station device 101. The base station device 101 includes, for example, an antenna information acquisition unit 401, a setting information notification unit 402, and an SRS measurement unit 403. The functions illustrated in FIG. 4 can be implemented, for example, by the processor 201 executing a program stored in the ROM 202 or the storage device 204. Note that this is just one example, and some or all of the functions illustrated in FIG. 4 may be implemented by dedicated hardware. Furthermore, FIG. 4 illustrates only functions related to the present embodiment among the functions possessed by the base station device 101, and the base station device 101 may naturally have functions other than those illustrated in FIG. 4, such as functions naturally possessed by a base station device in a cellular communication system.

[0030] The antenna information acquisition unit 401 acquires information about the multiple antennas that the terminal device 111 has from the terminal device 111. The setting information notification unit 402 generates SRS setting information for each of multiple groups into which multiple antennas are grouped, based on the information acquired by the antenna information acquisition unit 401, and notifies the terminal device 111. The SRS measurement unit 403 uses the setting information notified by the setting information notification unit 402 to measure the SRS transmitted from each of the multiple antennas of the terminal device 111, and performs processing such as transmission channel estimation.

[0031] In one example, the antenna information acquisition unit 401 acquires, from the terminal device 111, information about a plurality of groups to which a plurality of antennas owned by the terminal device 111 are respectively assigned. The setting information notification unit 402 generates SRS setting information for each of the plurality of groups based on the information about the plurality of groups, and notifies the terminal device 111. The SRS measurement unit 403 uses this setting information to measure the SRS transmitted from each of the plurality of antennas of the terminal device 111. Note that the setting information notification unit 402 can generate setting information according to, for example, the number of antennas belonging to each group.

[0032] In another example, the antenna information acquisition unit 401 acquires from the terminal device 111 the total number of multiple antennas that the terminal device 111 has. Then, the setting information notification unit 402 generates setting information for SRSs in a number corresponding to the number of groups to which the multiple antennas should be assigned, and notifies the terminal device 111 of the same. Note that the setting information notification unit 402 may, for example, determine the number of groups from the total number of multiple antennas that the terminal device 111 has in accordance with a predetermined rule, generate setting information related to SRSs for that number, and notify the terminal device 111 of the same. The setting information here includes the number of antennas that belong to a group and the setting of the SRS used in that group. The SRS measurement unit 403 uses this setting information to measure the SRS transmitted from each of the multiple antennas of the terminal device 111.

[0033] In another example, the antenna information acquisition unit 401 acquires, from the terminal device 111, information capable of identifying each of the multiple antennas possessed by the terminal device 111 (and, if necessary, information on the total number of antennas). The setting information notification unit 402 groups the multiple antennas, for example, according to a predetermined rule. The setting information notification unit 402 then generates setting information related to SRS for each of the multiple groups obtained by grouping the multiple antennas, and notifies the terminal device 111 of this information together with information indicating which of the multiple antennas is assigned to each of the multiple groups. The SRS measurement unit 403 uses this setting information to measure the SRS transmitted from each of the multiple antennas of the terminal device 111.

[0034] (Processing flow) Next, a description will be given of an example of the flow of processing executed between the base station device 101 and the terminal device 111. Note that the following processing example is just an example, and the grouping of antennas possessed by the terminal device 111 and the setting of SRS for the groups may be performed by procedures other than these.

[0035] 5 is a diagram showing a first processing example. In this processing example, the terminal device 111 groups a plurality of antennas that the terminal device 111 has (S501). Here, it is assumed that the terminal device 111 has eight antennas, antennas 1 to 8, and has grouped antennas 1 to 8 into a first group including antennas 1 to 4 and a second group including antennas 5 to 8. The terminal device 111 then notifies the base station device 101 of information related to the groups (S502). In this processing example, it is assumed that the terminal device 111 has notified the base station device 101 of information that can identify, for example, that antennas 1 to 4 belong to group 1 and that antennas 5 to 8 belong to group 2. The base station device 101 determines the SRS configuration for each group based on this information (S503). Here, it is assumed that the resource elements to be used for transmitting SRS between setting A for the first group and setting B for the second group differ in at least either the time domain or the frequency domain, and that at least the resource elements used in the time domain differ. The base station device 101 notifies the terminal device 111 of setting information including the determined setting (S504). Here, since the base station device 101 has been notified of the antennas belonging to each group, the base station device 101 can notify the terminal device 111 of the SRS-related setting for each group, including the individual antenna setting. Thereafter, the terminal device 111 applies the setting corresponding to each group to the antennas belonging to that group, and transmits the SRS (S505, S506).

[0036] 6 is a diagram showing a second processing example. In this processing example, first, the terminal device 111 notifies the base station device 101 of information indicating the total number of antennas that the terminal device 111 has (S601). Upon acquiring the information indicating the total number of antennas, the base station device 101 determines the number of groups to which the antennas are assigned in order to configure SRS for each of the antennas, and determines SRS-related configuration for each of the groups (S602). The base station device 101 then notifies the terminal device 111 of the number of antennas to belong to each group and configuration information related to SRS (S603). For example, if the terminal device 111 has a total of eight antennas, the base station device 101 defines two groups, each with four antennas, determines SRS-related configuration for each of the two groups, and notifies the terminal device 111. In FIG. 6, the terminal device 111 is notified that the number of antennas to belong to both the first group and the second group is four, and that SRS setting A for the first group and SRS setting B for the second group are different. In this processing example, it is assumed that setting A for the first group and setting B for the second group differ in resource elements used at least in the time domain. Based on this notification, the terminal device 111 groups the multiple antennas it owns (S604). That is, the terminal device 111 selects antennas from the multiple antennas equal to the number of antennas specified for each group and assigns the selected antennas to the group. For example, in FIG. 6, it is assumed that the number of antennas for both the first group and the second group is four, and therefore the terminal device 111 assigns antennas 1 to 4 to the first group and antennas 5 to 8 to the second group. As a result, the terminal device 111 transmits SRS using SRS setting A for the first group from antennas 1 to 4 (S605), and transmits SRS using SRS setting B for the second group from antennas 5 to 8 (S605).

[0037] FIG. 7 is a diagram showing a third processing example. In this processing example, the terminal device 111 notifies the base station device 101 of information that can identify each of the multiple antennas that the terminal device 111 has (S701). That is, the terminal device 111 notifies the base station device 101 of information that can identify each of antennas 1 to 8. The base station device 101 then groups the multiple antennas (S702). For example, the base station device 101 groups antennas 1 to 4 into a first group and antennas 5 to 8 into a second group. The base station device 101 then determines SRS-related settings for each group obtained by grouping (S703) and notifies the terminal device 111 of the information (S704). Here, because the base station device 101 has determined the antennas that belong to each group, the base station device 101 can notify the terminal device 111 of the SRS-related settings for each group, including individual antenna settings. In this processing example, it is also assumed that the resource elements used in at least the time domain are different between setting A for the first group and setting B for the second group. After that, the terminal device 111 applies the setting corresponding to each group to the antenna belonging to that group and transmits the SRS (S705, S706).

[0038] In this way, multiple antennas possessed by the terminal device 111 are grouped, and settings are prepared for each group so that SRS is transmitted in separate resource elements in each group. As a result, when the terminal device 111 has multiple antennas, it becomes possible to transmit SRS from each of the multiple antennas, and to perform highly accurate transmission channel estimation based on the SRS in 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 "Develop resilient infrastructure, promote sustainable industrialization, and foster innovation."

[0039] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

Claims

1. A terminal device having a plurality of antennas, a grouping means for allocating the plurality of antennas to a plurality of groups including a first group and a second group, the grouping means allocating four or less antennas of the plurality of antennas to the first group and four or less antennas of the plurality of antennas that are not allocated to the first group to the second group; a notification means for notifying a base station device of information designating antennas assigned to each of the plurality of groups by the grouping means; an acquisition means for acquiring, from the base station device, a configuration related to a sounding reference signal (SRS) for each of the plurality of groups, the configuration including a first configuration related to the SRS for the first group and a second configuration related to the SRS for the second group that is different from the first configuration, the second configuration including a configuration specifying that the SRS is to be transmitted using a resource element different from the first configuration; a transmitting means for transmitting an SRS from an antenna belonging to the first group using the first setting and transmitting an SRS from an antenna belonging to the second group using the second setting; A terminal device comprising:

2. The first setting includes information that specifies a resource element that is different in the time domain from a resource element from which the SRS specified in the second setting should be transmitted as a resource element from which the SRS should be transmitted. The terminal device according to claim 1,

3. 2. The terminal device according to claim 1, wherein the notification means further notifies the terminal device of the number of antennas included in the plurality of antennas that the terminal device has.

4. A base station device, an acquiring means for acquiring information specifying antennas respectively assigned to a plurality of groups by a terminal device, the information indicating that four or less antennas among a plurality of antennas possessed by the terminal device are assigned to a first group, and four or less antennas among the plurality of antennas that are not assigned to the first group are assigned to a second group; a notification means for notifying the terminal device of a setting related to a sounding reference signal (SRS) for each of the plurality of groups, the setting including a first setting related to the SRS for the first group and a second setting related to the SRS for the second group that is different from the first setting, the second setting including a setting specifying that the SRS is to be transmitted using a resource element different from the first setting; a measurement means for measuring an SRS transmitted from an antenna belonging to the first group using the first setting and for measuring an SRS transmitted from an antenna belonging to the second group using the second setting; A base station device comprising:

5. The base station apparatus according to claim 4, characterized in that the first setting includes information that specifies, as the resource element to be transmitted, a resource element that is different in the time domain from the resource element to be transmitted by the SRS specified in the second setting.

6. The base station device according to claim 4 , wherein the acquisition means further acquires the number of antennas included in the plurality of antennas that the terminal device has.

7. A control method executed by a terminal device having multiple antennas, comprising: assigning the plurality of antennas to a plurality of groups including a first group and a second group, wherein four or less antennas of the plurality of antennas are assigned to the first group, and four or less antennas of the plurality of antennas that are not assigned to the first group are assigned to the second group; notifying a base station device of information designating antennas assigned to each of the plurality of groups; acquiring, from the base station device, configurations for a sounding reference signal (SRS) for each of the plurality of groups, including a first configuration for the SRS for the first group based on the notification and a second configuration for the SRS that is different from the first configuration for the second group, the second configuration including a configuration specifying that the SRS is to be transmitted using a resource element different from that of the first configuration; Transmitting an SRS using the first configuration from antennas belonging to the first group and transmitting an SRS using the second configuration from antennas belonging to the second group; A control method comprising:

8. A control method executed by a base station device, acquiring information specifying antennas respectively assigned to a plurality of groups by a terminal device, the information indicating that four or less antennas among a plurality of antennas possessed by the terminal device are assigned to a first group, and four or less antennas among the plurality of antennas that are not assigned to the first group are assigned to a second group; notifying the terminal device of a configuration related to a sounding reference signal (SRS) for each of the plurality of groups, the configuration including a first configuration related to the SRS for the first group and a second configuration related to the SRS for the second group that is different from the first configuration, the second configuration including a configuration specifying that the SRS is to be transmitted using a resource element different from the first configuration; measuring an SRS transmitted by an antenna belonging to the first group using the first configuration and measuring an SRS transmitted by an antenna belonging to the second group using the second configuration; A control method comprising:

9. A program for causing a computer to function as the terminal device according to any one of claims 1 to 3.

10. A program for causing a computer to function as the base station device according to any one of claims 4 to 6.

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