Terminal device for efficient communication using a plurality of component carriers, base station device, control method, and program

Abstract

According to the present invention, in dual connectivity or carrier aggregation, for each combination of component carriers (CCs) used in the dual connectivity or carrier aggregation, a terminal device reports, to a connection-destination base station device, capability information including: information indicating a combination of the number of layers of Multi-Input Multi-Output (MIMO) in each of a plurality of CCs that can be used by the terminal device; and information about performance requirements including at least one of the reception timing difference and the reception power difference to be satisfied by a reception signal at the terminal device for each of the plurality of CCs in order to enable the terminal device to receive signals of the plurality of CCs with a prescribed quality if the number of MIMO layers indicated by the combination is used in each of the plurality of CCs.

Description

Terminal device, base station device, control method, and program for efficient communication using multiple component carriers

[0001] The present invention relates to a technique for effectively utilizing a plurality of component carriers in a cellular communication system.

[0002] The cellular communication standard of the Third Generation Partnership Project (3GPP (registered trademark)) specifies technologies for communication using multiple component carriers (CCs, carrier waves), known as dual connectivity (DC) and carrier aggregation (CA). It is expected that communication performance using such multiple CCs will be significantly degraded if the difference in received power between the CCs is large, particularly when a single communication circuit in a terminal device processes communication of the multiple CCs. Patent Document 1 indicates that when a single communication circuit is used in a terminal device, the degradation in communication performance is significant, while when two communication circuits are used, a relatively large difference in received power between the two CCs is acceptable.

[0003] Japanese Patent Application Laid-Open No. 2023-117931

[0004] As the communication performed in each CC becomes more sophisticated, it is expected that the quality of communication using multiple CCs will be significantly deteriorated even if the terminal device simply has two communication circuits. Also, even if the terminal device has only one communication circuit, it is expected that the reception performance of the terminal device will be improved so that the reception processing of signals via multiple CCs with large transmission power differences will be performed with sufficiently high quality.

[0005] The present invention provides a technique that enables communication using a plurality of component carriers in an appropriate configuration according to the processing capacity of a terminal device.

[0006] A terminal device according to one aspect of the present invention includes capability information of the terminal device, the capability information including, for each combination of component carriers (CCs) used in dual connectivity or carrier aggregation, information indicating a combination of the number of layers of Multi-Input Multi-Output (MIMO) for each of a plurality of CCs that the terminal device can use in dual connectivity or carrier aggregation, and information on performance requirements including at least one of a reception timing difference and a reception power difference that a received signal for each of the plurality of CCs must satisfy in order to enable the terminal device to receive signals of the plurality of CCs with a predetermined quality when MIMO with the number of layers indicated by the combination is used for each of the plurality of CCs; and notification means for receiving control information from the base station device including information on the number of layers of MIMO used in the plurality of CCs, and controlling reception processing of signals in the plurality of CCs based on the control information.

[0007] A base station apparatus according to one aspect of the present invention includes: receiving means for receiving, from a terminal apparatus, capability information of a connected terminal apparatus, the capability information including, for each combination of component carriers (CCs) used in dual connectivity or carrier aggregation, information indicating a combination of the number of layers of Multi-Input Multi-Output (MIMO) in each of a plurality of CCs that the terminal apparatus can use, and information on performance requirements including at least one of a reception timing difference and a reception power difference that a received signal in the terminal apparatus must satisfy for each of the plurality of CCs, in order to enable the terminal apparatus to receive signals of the plurality of CCs with a predetermined quality when MIMO with the number of layers indicated by the combination is used in each of the plurality of CCs; determining means for determining a configuration of the number of layers of MIMO to be used in the plurality of CCs based on the capability information; and notifying means for notifying the terminal apparatus of control information including the determined configuration.

[0008] According to the present invention, it is possible to perform communication using a plurality of component carriers in an appropriate configuration according to the processing capacity of the terminal device.

[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 into and constitute a part of the specification, illustrate embodiments of the present invention, and together with the description, are used to explain the principles of the present invention. FIG. 1 is a diagram showing an example of the configuration of a wireless communication system. FIG. 2 is a diagram showing an example of the configuration of a receiver of a terminal device. FIG. 3 is a diagram showing an example of the configuration of a receiver of a terminal device. FIG. 4 is a diagram showing an example of the configuration of a receiver of a terminal device. FIG. 5A is a diagram showing an example of information notified from a terminal device to a base station device. FIG. 5B is a diagram showing an example of information notified from a terminal device to a base station device. FIG. 5C is a diagram showing an example of information notified from a terminal device to a base station device. FIG. 6A is a diagram showing an example of information notified from a terminal device to a base station device. FIG. 6B is a diagram showing an example of information notified from a terminal device to a base station device. FIG. 6C is a diagram showing an example of information notified from a terminal device to a base station device. FIG. 7 is a diagram showing an example of classification of terminal device types. FIG. 8A is a diagram showing an example of information notified from a terminal device to a base station device. FIG. 8B is a diagram showing an example of information notified from a terminal device to a base station device. FIG. 8C is a diagram showing an example of information notified from a terminal device to a base station device. Fig. 9A is a diagram showing an example of information notified from a terminal device to a base station device. Fig. 9B is a diagram showing an example of information notified from a terminal device to a base station device. Fig. 9C is a diagram showing an example of information notified from a terminal device to a base station device. Fig. 10A is a diagram showing an example of information notified from a terminal device to a base station device. Fig. 10B is a diagram showing an example of information notified from a terminal device to a base station device. Fig. 11 is a diagram showing an example of the hardware configuration of a terminal device and a base station device. Fig. 12 is a diagram showing an example of the functional configuration of a terminal device. Fig. 13 is a diagram showing an example of the functional configuration of a base station device. Fig. 14 is a diagram showing an example of the flow of processing executed in a wireless communication system.

[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] FIG. 1 shows an example of the configuration of a wireless communication system according to the present embodiment. This wireless communication system conforms to the cellular communication standard of the Third Generation Partnership Project (3GPP (registered trademark)) and includes a base station device 101 and a terminal device 102. The cellular communication standard may be, for example, at least one of Long Term Evolution (LTE), New Radio (NR) for the fifth generation (5G), or a successor standard thereof. The terminal device 102 is configured to establish a connection with the base station device 101 and perform wireless communication. In this embodiment, the terminal device 102 is configured to perform communication using multiple carriers using dual connectivity (DC) or carrier aggregation (AC). For example, in FIG. 1, the terminal device 102 is configured to be able to communicate with the base station device 101 using a first carrier 111 and a second carrier 112. The first carrier 111 and the second carrier 112 are also referred to as component carriers (CCs). Hereinafter, the first carrier 111 may be referred to as the first CC, and the second carrier 112 may be referred to as the second CC. Two or more CCs may be included in a common frequency band (any one of the 800 MHz band, the 2 GHz band, the 3.5 GHz band, etc.), or each CC may be included in a different frequency band. Furthermore, the terminal device 102 may be connected to one base station device 101, or may be connected to multiple base station devices 101. For example, the terminal device 102 may be connected to a first base station device that provides a communication service using the first CC, while also being connected to a second base station device that provides a communication service using the second CC.

[0013] In order to enhance communication in each of the multiple CCs, it is assumed that multi-input multi-output (MIMO) communication will be performed. In MIMO communication, communication is performed using multiple antennas provided in the base station device 101 and multiple antennas provided in the terminal device 102. In this embodiment, MIMO communication using N antennas in the base station device 101 and M antennas in the terminal device 102 may be referred to as N × M MIMO. In this embodiment, as shown in FIG. 1, one or more base station devices 101 communicate with the terminal device 102 using up to four antennas in the first CC, and also communicate with the terminal device 102 using up to four antennas in the second CC. In this case, for example, if the terminal device 102 has eight antennas and corresponding communication processing circuits, four antennas can be used for communication in each CC, and 4 × 4 MIMO communication can be performed for each CC. On the other hand, the terminal device 102 may be required to reduce the number of antennas and circuit size, and it is expected that it may not be able to have eight antennas and circuits. Furthermore, for example, if communication services using the first CC and the second CC are provided by separate base station devices, the received power difference and received timing difference at the terminal device 102 of signals transmitted on those CCs may vary significantly. Furthermore, depending on whether the terminal device 102 can process signals of multiple CCs using separate circuits, the allowable received power difference and received timing difference (which can sufficiently suppress the effects of interference between signals) may vary significantly. For this reason, if the base station device 101 does not have sufficient knowledge about the configuration of the terminal device 102, it may set a MIMO configuration that prevents the terminal device 102 from communicating with sufficient quality. Furthermore, if the base station device 101 does not have sufficient knowledge, it may unnecessarily suppress the use of MIMO communication, even if the terminal device 102 can tolerate a sufficiently large received power difference and received timing difference, thereby reducing communication efficiency.

[0014] In this embodiment, in consideration of such circumstances, the terminal device 102 notifies the connected base station device 101 (network) of information on reception capabilities when MIMO communication is used in multiple CCs. Then, the base station device 101 controls the communication configuration based on the information. As a result, the base station device 101, for example, can identify a configuration that allows the terminal device 102 to receive signals via multiple CCs and specify that configuration to perform communication.

[0015] Here, several configuration examples of the receiver that the terminal device 102 may have will be described using Figures 2 to 4. Note that Figures 2 to 4 show the configuration of the receiver of the terminal device 102 merely as an example, and a receiver having a configuration that is a modification of the configurations in Figures 2 to 4 may be used, or a receiver having a configuration that is completely different from the configurations in Figures 2 to 4 may be used.

[0016] FIG. 2 shows an example in which the terminal device 102 has eight independent receiving circuits. As shown in FIG. 2, one receiving circuit includes an antenna, a diplexer, a low-noise amplifier (LNA), an internal LNA (iLNA), a mixer, a filter, and an analog-to-digital converter (ADC). A signal received via the antenna passes through the diplexer to form a signal of one frequency band, which is amplified by the LNA / iLNA, the mixer converts the signal's frequency band to a baseband band, and the ADC digitizes the input analog signal and outputs it to a digital baseband circuit (not shown). In the example of FIG. 2, there are eight such receiving circuit systems, each configured to operate independently. When the terminal device 102 has such a configuration, each system can perform receiving processing by focusing only on the signal of the CC to be processed. Therefore, for example, by using up to four systems for the first CC and up to four systems for the second CC, sufficient reception performance can be obtained even if the difference in reception timing or reception power between the received signal in the first CC and the received signal in the second CC is relatively large.

[0017] 3 shows a configuration example in which an antenna, diplexer, and LNA are shared by two systems. In this example, for example, a combination of an iLNA, a mixer, a filter, and an ADC that handles signals of two CCs respectively shares one set of antenna, diplexer, and LNA. When such sharing is performed, it is assumed that sufficient reception performance cannot be obtained unless the difference in reception timing and reception power between the received signals received in the two CCs is sufficiently small. Note that in the configuration of FIG. 3, for example, when 2×2 MIMO communication is performed in each of the two CCs, one set of iLNA, mixer, filter, and ADC that share one set of antenna, diplexer, and LNA does not need to be used. Therefore, in this case, sufficient reception performance can be obtained even if the difference in reception timing and reception power between the received signal in the first CC and the received signal in the second CC is relatively large. On the other hand, when 2x2 MIMO communication is performed in each of the two CCs, four receiving circuits can be used, each consisting of two sets of antennas, diplexers, and LNAs, and two sets of iLNAs, mixers, filters, and ADCs that share the same combination. In this case, it is possible to avoid using the remaining four receiving circuits, each consisting of the two sets of antennas, diplexers, and LNAs, and two sets of iLNAs, mixers, filters, and ADCs that share the same combination. As a result, it is required that the differences in reception timing and reception power between the received signal in the first CC and the received signal in the second CC be relatively small, and by performing communication within this required range, power consumption in the terminal device 102 can be reduced.

[0018] Figure 4 shows a configuration intermediate between Figures 2 and 3, in which two sets of antennas, diplexers, and LNAs are each shared by two systems, and two other sets of antennas, diplexers, and LNAs are used in only one system. When this configuration is used, there are only six combinations of iLNAs, mixers, filters, and ADCs, so, for example, 4x4 MIMO communication cannot be performed in each of the two CCs. In this case, 4x4 MIMO and 2x2 MIMO communication can be performed in each of the two CCs. Here, because two sets of antennas, diplexers, and LNAs are each shared by two systems, it is expected that sufficient reception performance cannot be obtained unless the difference in reception timing or reception power between the received signals received in the two CCs is sufficiently small. On the other hand, when 2x2 MIMO communication is performed in each of the two CCs, one set of iLNAs, mixers, filters, and ADCs that share one set of antennas, diplexers, and LNAs does not need to be used. Therefore, in this case, sufficient reception performance can be obtained even if the difference in reception timing or reception power between the received signal in the first CC and the received signal in the second CC is relatively large. On the other hand, when 2x2 MIMO communication is performed in each of the two CCs, four receiving circuits consisting of two sets of antennas, diplexers, and LNAs and two sets of iLNAs, mixers, filters, and ADCs that share these combinations can also be used. In this case, the remaining two sets (the lower two systems) of antennas, diplexers, LNAs, iLNAs, mixers, filters, and ADC receiving circuits can be omitted. As a result, it is required that the difference in reception timing and reception power between the received signal in the first CC and the received signal in the second CC be relatively small, and by carrying out communication within this required range, power consumption in the terminal device 102 can be reduced.

[0019] In the following, a receiving circuit in which an antenna, a diplexer, and an LNA are shared and used by multiple systems is referred to as a shared circuit. Furthermore, a receiving circuit in which an antenna, a diplexer, and an LNA are used by only one system is referred to as a separate circuit, in consideration of the separation of each system. For example, the configuration of FIG. 2 is called a separate circuit because, regardless of the type of communication performed between multiple CCs, the signals handled in each system are associated with only one CC. The configurations of FIGS. 3 and 4 are called shared circuits because, for example, when 4×4 MIMO communication is performed in at least one of two CCs, at least one combination of an antenna, a diplexer, and an LNA is shared by multiple systems. On the other hand, when 2×2 MIMO communication is performed in each of two CCs, the configurations of FIGS. 3 and 4 can be either a shared circuit or a separate circuit depending on the form of the circuit used.

[0020] For example, the terminal device 102 can notify the connected base station device 101 of information indicating whether communication using a separate circuit or a shared circuit is possible in communication of multiple CCs. For example, as shown in Figures 5A to 5C, when either 4x4 MIMO or 2x2 MIMO is used in each of two CCs, the terminal device 102 can notify the base station device 101 of whether communication can be performed using the shared circuit or the separate circuit.

[0021] FIG. 5A shows an example of information that a terminal device 102 having the configuration of FIG. 2 notifies a base station device 101, for example. As shown in FIG. 5A, when the terminal device 102 has the configuration of FIG. 2, it can perform both 4×4 MIMO and 2×2 MIMO communications using a separation circuit in each of the two CCs. On the other hand, when the terminal device 102 has the configuration of FIG. 2, it cannot perform communications using a shared circuit. FIG. 5B shows an example of information that a terminal device 102 having the configuration of FIG. 3 notifies a base station device 101, for example. As shown in FIG. 5B, when the terminal device 102 has the configuration of FIG. 3, it can perform 4×4 MIMO communications in each of the two CCs, and can perform 4×4 MIMO communications in one CC while performing 2×2 MIMO communications in the other CC using a shared circuit, but it cannot perform these communications using a separation circuit. Furthermore, when the terminal device 102 has the configuration of Figure 3, when performing 2x2 MIMO communication in each of the two CCs, the communication can be performed using either a separation circuit or a shared circuit. Figure 5C shows an example of information that a terminal device 102 having the configuration of Figure 4 notifies the base station device 101. As shown in Figure 5C, when the terminal device 102 has the configuration of Figure 4, it cannot perform 4x4 MIMO communication in each of the two CCs even if it uses a shared circuit. On the other hand, other cases are the same as those in the configuration of Figure 3.

[0022] When the base station device 101 receives information such as those shown in FIGS. 5A to 5C from the terminal device 102, it can determine the configuration in which the terminal device 102 can perform communications. As an example, assume that the base station device 101 receives information such as that shown in FIG. 5C from the terminal device 102. In this case, the base station device 101 may determine that 4×4 MIMO communication is not possible on both two CCs (the first CC and the second CC). Furthermore, the base station device 101 may determine that 4×4 MIMO communication is possible on one of the first CC and the second CC, and 2×2 MIMO communication is possible on the other, provided that a shared circuit is used in the terminal device 102. Furthermore, the base station device 101 may determine that 2×2 MIMO communication is possible on both the first CC and the second CC, regardless of whether a shared circuit or a separate circuit is used in the terminal device 102.

[0023] Here, for example, assume that one base station device 101 communicates with a terminal device 102. In this case, if signals are transmitted at the same timing using similar power in the first CC and the second CC, it is assumed that the difference in reception timing and reception power between the received signal in the first CC and the received signal in the second CC will be sufficiently small in the terminal device 102. That is, in this case, it is assumed that the terminal device 102 can receive signals of the first CC and the second CC with sufficient quality even if it uses a shared circuit. Therefore, in such a case, the base station device 101 assumes that the shared circuit can be applied to the terminal device 102, and can communicate with the terminal device 102 by selecting either a configuration in which only one of the first CC and the second CC uses 4x4 MIMO and the other uses 2x2 MIMO, or a configuration in which both the first CC and the second CC use 2x2 MIMO, which are communication possible using the shared circuit. In addition, when the base station device 101 decides to use a configuration using 2x2 MIMO in both the first CC and the second CC, it can further decide whether to have the terminal device 102 use a shared circuit or a separate circuit.

[0024] On the other hand, for example, when communication on the first CC and communication on the second CC are provided by separate base station devices 101, it is expected that the difference in reception timing and reception power between the received signal on the first CC and the received signal on the second CC will be large in the terminal device 102. In this case, if cooperative operation can be performed between multiple base station devices 101 to sufficiently reduce the difference in reception timing and reception power, it is expected that the terminal device 102 will be able to communicate with sufficiently high quality even if it uses a shared circuit. On the other hand, if such cooperative operation cannot be performed between multiple base station devices 101, communication quality may be degraded if the terminal device 102 uses a shared circuit. For this reason, the base station device 101 (e.g., a master base station) providing communication on one of the CCs may decide to have the terminal device 102 use a separate circuit, and may decide, for example, to use a configuration using 2×2 MIMO in both the first CC and the second CC.

[0025] In this way, the terminal device 102 can notify the base station device 101 of information indicating whether a separation circuit or a shared circuit can be used when performing MIMO communication using multiple CCs. This allows the base station device 101 to determine the number of MIMO layers (4x4, 2x2, etc.) to be used in each of multiple CCs, taking into account the receiver configuration of the terminal device 102. While the above example describes the case where two CCs are used, three or more CCs may also be considered. For example, as shown in Figures 6A to 6C, when either 4x4 MIMO or 2x2 MIMO is used in each of three CCs, the terminal device 102 can notify the base station device 101 of whether communication can be performed using a shared circuit or a separation circuit. In one example, Figure 6A corresponds to the configuration of Figure 2, Figure 6B corresponds to the configuration of Figure 3, and Figure 6C corresponds to the configuration of Figure 4. When three CCs are used, the configurations of Figures 2 to 4 only allow for signal processing of up to eight systems. Therefore, configurations in which the total number of streams exceeds eight, such as a configuration in which 4x4 MIMO is used in two or more of the three CCs, are not shown. Note that the terminal device 102 can naturally have a receiving circuit capable of processing more than eight streams. Depending on the configuration, information regarding the availability of 4x4 MIMO for each of the three or more CCs may be notified to the base station device 101. Note that Figures 5A to 5C and 6A to 6C only show the number of MIMO layers for each CC and whether communication is possible with that number of layers, but this is not limited to this. For example, information such as the fact that a specific combination of CCs can be processed using a shared circuit, but other combinations cannot be processed even using a shared circuit, may be notified from the terminal device 102 to the base station device 101. For example, at least one of information indicating a combination of CCs that can be processed using a shared circuit and information indicating a combination of CCs that cannot be processed using a shared circuit may be notified from the terminal device 102 to the base station device 101.

[0026] 2 to 4, the type of the terminal device 102 may be defined in advance, and the terminal device 102 may notify the base station device 101 of the type of receiver configuration of the terminal device 102. FIG. 7 shows an example of information indicating the receiver type of the terminal device 102. In FIG. 7, UE Type = 1 corresponds to a configuration in which four receiving circuits (a total of eight) are available for each of two CCs, and the receiving circuits share not only antennas and LNAs but also mixers. UE Type = 2 corresponds to a configuration in which two receiving circuits (a total of four) are provided for each CC, each having a separate antenna. In other words, UE Type = 2 corresponds to a configuration in which the number of systems is four in the configuration as shown in FIG. 2. Similarly, UE Type = 3a corresponds to the configuration of FIG. 4, UE Type = 3b corresponds to the configuration of FIG. 3, UE Type = 4a corresponds to a configuration in which the number of systems is four in the configuration of FIG. 2, and UE Type = 4b corresponds to the configuration of FIG. 2. The terminal device 102 can notify the base station device 101 of the UE Type 1 to 4b of the receiver configuration of its own device. Note that the configurations and UE Types shown in FIGS. 2 to 4 are merely examples. For example, in the above example, one diplexer and one LNA are associated with one antenna, but this configuration is not limited thereto. For example, two or more diplexers or LNAs and subsequent circuits may be associated with one antenna, or one diplexer or LNA and subsequent circuits may be associated with two antennas. Furthermore, for example, a plurality of digital baseband processing circuits may be provided and connected downstream of the configurations shown in Figures 2 to 4. Here, one digital baseband processing circuit may process only one CC, or may process multiple CCs. Furthermore, multiple digital baseband processing circuits may be configured to process one CC. In this case, whether the above-mentioned shared circuit can be used may be determined by considering whether the digital baseband processing circuit can be shared for communication processing of multiple CCs.

[0027] In addition, even when the terminal device 102 uses a shared circuit, for example, even when the reception timing difference or reception power difference of the received signals from each of the multiple CCs is relatively large due to, for example, the signal processing capability, it may be possible to perform reception processing with sufficiently high quality. In this case, if the UE Type information as described above is simply notified to the base station device 101, the base station device 101 may select a configuration that is conservative compared to the actual capabilities of the terminal device 102 (i.e., relatively inefficient compared to the capabilities of the terminal device 102). For this reason, the terminal device 102 may notify the base station device 101 of performance requirement information, which indicates what requirements must be met in each CC to enable signals to be received with sufficient quality, regardless of the receiver configuration.

[0028] For example, the performance requirements may be specified by the Maximum Receive Timing Difference (MRTD), which indicates the maximum value of the receive timing difference between CCs, or the maximum value of the receive power difference (Power Imbalance) between CCs. As an example, a performance requirement in which the allowable MRTD is 33 microseconds (μs) and the allowable receive power difference is 25 dB is referred to as performance requirement A. Furthermore, a performance requirement in which the allowable MRTD is 3 μs and the allowable receive power difference is 6 dB is referred to as performance requirement B. Performance requirement B is a performance requirement that is expected to be achieved, for example, when the same base station device provides communications using multiple CCs, or when multiple base station devices located in the same location each provide communications using separate CCs, and performance requirement A is a performance requirement that is expected to be achieved even when multiple base station devices located in different locations each provide communications using separate CCs. In addition to performance requirement A and performance requirement B, another requirement may be provided, for example, that the MRTD is greater than 3 μs and less than 33 μs, or that the maximum value of the received power difference is greater than 6 dB and less than 25 dB. Another requirement may be provided, for example, that the MRTD is less than 3 μs or greater than 33 μs, or that the maximum value of the received power difference is less than 6 dB or more than 25 dB. Values ​​such as 3 μs, 33 μs, 6 dB, and 25 dB are merely examples, and values ​​other than these may be used to define the performance requirements. Furthermore, MRTD can be used as a performance requirement in the case of downlink dual connectivity or carrier aggregation, but in the case of uplink dual connectivity or carrier aggregation, maximum uplink transmission timing difference (MTTD) may be used as a performance requirement instead of MRTD.

[0029] The terminal device 102 can notify the base station device 101 of information indicating which performance requirement must be satisfied to enable communications with sufficient quality for a combination of the number of MIMO layers in each CC. FIGS. 8A to 8C show examples of the performance requirement information notified in this case. Note that FIG. 8A corresponds to the configuration of FIG. 2, FIG. 8B corresponds to the configuration of FIG. 3, and FIG. 8C corresponds to the configuration of FIG. 4. Note that in the examples of FIGS. 8A to 8C, performance requirement A is satisfied when communications can be performed using a separation circuit, and performance requirement B is satisfied when communications cannot be performed using a separation circuit but can be performed using a shared circuit. The terminal device 102 having the configuration of FIG. 2 can communicate using a separation circuit for each combination of the number of MIMO layers in a CC, and can communicate with sufficient quality if "performance requirement A" is satisfied for each configuration. For this reason, such a terminal device 102 notifies the base station device 101 of information indicating "performance requirement A" as information on the performance requirement corresponding to each combination, as shown in FIG. 8A. Furthermore, the terminal device 102 having the configuration of FIG. 3 can perform communication using a shared circuit for each combination of the number of MIMO layers in the CC, and can also perform communication using a separate circuit when 2×2 MIMO communication is performed in both the first CC and the second CC. That is, if "performance requirement A" is satisfied for a combination in which both the first CC and the second CC use 2×2 MIMO, communication can be performed with sufficient quality, and if "performance requirement B" is satisfied for other combinations, communication can be performed with sufficient quality. For this reason, such a terminal device 102 notifies the base station device 101 of information on the performance requirements corresponding to each combination, as shown in FIG. 8B. Furthermore, the terminal device 102 having the configuration of FIG. 4 cannot perform communication when 4×4 MIMO is used in two CCs, but can perform processing similar to that of the terminal device 102 having the configuration of FIG. 3 in other configurations. Therefore, such a terminal device 102 notifies the base station device 101 of information on performance requirements corresponding to each combination, as shown in FIG. 8C.

[0030] Note that the relationship between the configuration of the terminal device 102 and the performance requirements that enable communication with sufficient quality in the above description is merely an example. That is, even if the terminal device 102 has a configuration such as that shown in FIG. 2, communication using a shared circuit can be configured to be possible by using a common digital baseband processing circuit for received signals of multiple CCs. Even if a shared circuit is used, a terminal device 102 that enables communication with sufficient quality under requirements (e.g., performance requirement A) that are more relaxed than performance requirement B due to the sophistication of the circuit may be used. Regardless of the configurations such as those shown in FIGS. 2 to 4, the terminal device 102 can notify the base station device 101 of information on performance requirements (e.g., at least one of a reception timing difference and a reception power difference) that must be satisfied for communication using that combination to be possible at a predetermined communication quality for each combination of the number of MIMO layers in each of multiple CCs.

[0031] 8A to 8C show performance requirements that must be met when the terminal device 102 communicates, and when those performance requirements are met or when stricter requirements are met, the terminal device 102 can communicate at a predetermined quality. That is, when the terminal device 102 is capable of communication at a predetermined quality when performance requirement A is met for a combination of a predetermined number of MIMO layers in each of a plurality of CCs, it is also capable of communication at a predetermined quality when performance requirement B is met. For this reason, when the base station device 101 receives information such as that shown in FIG. 8A, it does not recognize whether a separate circuit or a shared circuit is used in the terminal device 102, but it can recognize that the terminal device 102 can receive signals at a predetermined quality if performance requirement A or a stricter requirement is met.

[0032] For example, instead of the information shown in Figures 8A to 8C, information on performance requirements for enabling signals to be received with a predetermined quality in communications using a separated circuit and a shared circuit, respectively, may be notified from terminal device 102 to base station device 101, as shown in Figures 9A to 9C.

[0033] 8A to 8C and 9A to 9C show examples in which information about two CCs is notified, but similar information can also be notified when three or more CCs are available. For example, as shown in FIGS. 6A to 6C, combinations of the number of MIMO layers in three CCs are defined, and performance requirements that enable communication with a predetermined quality when the combinations are used can be notified. For example, in the information corresponding to FIG. 6B, if 4×4 MIMO is used in one of the first to third CCs and 2×2 MIMO is used in the other CCs, a shared circuit will be used, and performance requirement B will be notified for these combinations. On the other hand, if 2×2 MIMO is used in each of the first to third CCs, it is assumed that a shared circuit will be used for two of these three CCs and a separate circuit will be used for the remaining CC. For this reason, for example, information such as performance requirement B for the first CC and the second CC and performance requirement A for the third CC can be notified from the terminal device 102 to the base station device 101. Note that different information may be notified depending on which of the first CC to the third CC a separation circuit is used for. For example, FeatureSetsPerBands (described later) may be notified for three patterns: when a separation circuit is used for the first CC, when a separation circuit is used for the second CC, and when a separation circuit is used for the third CC. Also, for example, when three CCs are used, five patterns can be considered: a pattern in which the received signals of the three CCs are all processed by a common shared circuit (pattern 1); a pattern in which the first and second CCs are processed by a shared circuit and the third CC is processed by a separation circuit (pattern 2); a pattern in which the first and third CCs are processed by a shared circuit and the second CC is processed by a separation circuit (pattern 3); a pattern in which the second and third CCs are processed by a shared circuit and the first CC is processed by a separation circuit (pattern 4); and a pattern in which the first to third CCs are each processed by a separation circuit (pattern 5).Here, for each combination of the number of MIMO layers used in multiple CCs, information on performance requirements for each of these five patterns may be notified from the terminal device 102 to the base station device 101. For example, for each pattern, information on performance requirements between two of the three CCs may be notified. That is, three performance requirements may be notified for each pattern: the performance requirement between the first CC and the second CC, the performance requirement between the first CC and the third CC, and the performance requirement between the second CC and the third CC. Furthermore, for each combination of the number of MIMO layers used in multiple CCs, a bitmap indicating whether each of these five patterns is usable may be notified. That is, whether communication is possible using patterns 1 to 5 may be indicated by five bits of information. In one example, a bitmap of "11110" may indicate that communication is possible using patterns 1 to 4, but that communication is not possible using pattern 5. Such a bitmap may be notified for each combination of the number of MIMO layers used in multiple CCs. A first bitmap indicating a pattern in which communication is possible when performance requirement A is satisfied and a second bitmap indicating a pattern in which communication is possible when performance requirement B is satisfied may be notified to the base station device 101. When three or more CCs are used, the terminal device 102 may notify the base station device 101 of only the combinations of CCs that can satisfy performance requirement A. When, for example, one system such as an antenna / diplexer / LNA is branched into three or more systems and three or more CCs included in a signal received from one antenna are configured to be processed, information on the requirements for collectively processing the signals of these three or more CCs may be notified from the terminal device 102 to the base station device 101.

[0034] The above information may be notified from the terminal device 102 to the base station device 101 using, for example, UE Capability (capability information) defined in a cellular communication standard. In one example, the above information may be notified using FeatureSetsPerBands, which is an element of information related to Band Combination included in UE Capability. For example, when information such as that shown in FIGS. 5A to 5C or 6A to 6C is notified, FeatureSetsPerBands may be configured to include, for example, information on the number of layers of each CC for each combination of CCs used in dual connectivity or carrier aggregation, and information indicating whether a separate circuit can be used and whether a shared circuit can be used. FIG. 10A shows an example of information that may be included in FeatureSetsPerBands when information such as that shown in FIG. 5B is notified. 8A to 8C or 9A to 9C is notified, FeatureSetsPerBands can be configured to include, for example, information on the number of layers of each CC for each combination of CCs and the performance requirements (P / R) required when performing communication for that combination of layer numbers (for each separated circuit / shared circuit in the case of FIGS. 9A to 9C). Figure 10B shows an example of information to be included in FeatureSetsPerBands when information such as that of FIG. 8B is notified. Note that for a combination of the number of MIMO layers for which communication is not possible, information indicating that communication is not possible may be notified, or notification of information regarding that combination may be omitted.

[0035] The predetermined quality to be obtained when the performance requirement is satisfied may be defined, for example, by a throughput value. For example, the performance requirement may be defined by a throughput value (e.g., 80% of the theoretical value) to be satisfied when the reception power difference is a predetermined value (e.g., 6 dB or 25 dB). Furthermore, the performance requirement may be defined by a throughput value (e.g., 80% of the theoretical value) to be satisfied when the reception timing difference is a predetermined value (e.g., 3 μs or 33 μs).

[0036] When the base station device 101 receives the above-described information, it can determine, based on that information, the MIMO configuration to be used for each CC in communication with the terminal device 102. In one example, the base station device 101 receives from the terminal device 102 information on the received power and reception timing at the terminal device 102 for signals (e.g., reference signals such as synchronization signals and channel state information-reference signals) transmitted from each CC to be used in communication with the terminal device 102. This allows the base station device 101 to identify the received power difference and reception timing difference at the terminal device 102 for signals transmitted using each CC. The base station device 101 can then determine the MIMO configuration to be used in communication with the terminal device 102 according to the received power difference and reception timing difference. For example, if the received power difference or reception timing difference exceeds a predetermined value (e.g., 6 dB or 3 μs), the base station device 101 can determine to use a MIMO configuration that enables communication using a separation circuit. Furthermore, if the difference in received power or received timing does not exceed a predetermined value, it may be determined to use either a separate circuit or a shared circuit. Note that, for a specific CC combination, if the difference in received power or received timing exceeds a second predetermined value (e.g., 25 dB or 33 μs), the base station device 101 may determine not to use that CC combination. Note that, when three or more CCs are used, the above-mentioned determination may be made based on the maximum value of the difference in received power or received timing.

[0037] The base station device 101 may, for example, measure signals transmitted from the terminal device 102 on each CC to estimate the received power difference or the received timing difference between CCs at the terminal device 102, or may determine the received timing difference between CCs at the terminal device 102 based on, for example, timing advance values ​​for each CC set for the terminal device 102. Furthermore, when multiple CCs are provided by a single base station device 101 or by multiple base station devices 101 located at the same location (or within a predetermined distance range where they can be treated as being at the same location), the base station device 101 may estimate that the received power difference or the received timing difference will be equal to or less than a predetermined value, regardless of the actual measured values ​​of signals at the terminal device 102, etc. On the other hand, when multiple CCs are provided by multiple base station devices 101 located at different locations (outside a predetermined distance range where they cannot be treated as being at the same location), the base station device 101 may estimate that the received power difference or the received timing difference will be equal to or greater than a predetermined value, regardless of the actual measured values ​​of signals at the terminal device 102, etc.

[0038] In addition to the MIMO configuration for each CC, the base station device 101 may determine whether the terminal device 102 should use a demultiplexing circuit or a shared circuit. For example, if only one of the demultiplexing circuit and the shared circuit can be used for communication in the determined MIMO configuration, which of these circuits should be used is uniquely determined. On the other hand, if both the demultiplexing circuit and the shared circuit can be used for communication in the determined MIMO configuration, the base station device 101 may determine which of them to use. For example, when a demultiplexing circuit is used, more circuit parts must be operated in the terminal device 102 than when a shared circuit is used, resulting in higher power consumption. For this reason, the base station device 101 may determine to have the terminal device 102 use the shared circuit when the terminal device 102 should operate in a more power-saving state. On the other hand, when a demultiplexing circuit is used, communication reliability can be improved, for example, by maintaining communication even when the reception timing difference or reception power difference becomes large due to a change in the situation. Therefore, when communication reliability needs to be improved, the base station device 101 may decide to have the terminal device 102 use a separate circuit, and the base station device 101 may notify the terminal device 102 of information indicating whether to use a separate circuit or a shared circuit.

[0039] 10A from the terminal device 102, the base station device 101 determines to use 4×4 MIMO in both the first CC and the second CC. In this case, the base station device 101 can notify the terminal device 102 of information specifying the number of MIMO layers (maxMIMO-Layers) of the first CC = 4, the number of MIMO layers of the second CC = 4, and the reception method = shared circuit. In this case, the information on the reception method = shared circuit can be uniquely determined by the number of MIMO layers, and therefore the information does not need to be notified to the terminal device 102. Furthermore, when the base station device 101 determines to use 2×2 MIMO for both the first CC and the second CC, and determines to use a separation circuit, the base station device 101 can notify the terminal device 102 of information specifying the number of MIMO layers for the first CC=2, the number of MIMO layers for the second CC=2, and the reception method=separation circuit. Furthermore, when the base station device 101 determines to use a shared circuit, the base station device 101 can notify the terminal device 102 of information specifying the number of MIMO layers for the first CC=2, the number of MIMO layers for the second CC=2, and the reception method=shared circuit.

[0040] The base station device 101 may not determine or notify whether the separate circuit or the shared circuit should be used, and the terminal device 102 may instead determine whether the separate circuit or the shared circuit should be used. For example, as described above, the terminal device 102 may determine whether to use the separate circuit or the shared circuit based on criteria such as power consumption and communication reliability requirements, without relying on instructions from the base station device 101. Furthermore, if the terminal device 102 does not receive information specifying whether to use the separate circuit or the shared circuit, it may determine which circuit to use based on a pre-setting.

[0041] The terminal device 102 may notify the base station device 101 as capability information whether it has the capability to accept designation of whether a separate circuit or a shared circuit should be used. If the terminal device 102 has that capability, the base station device 101 may notify the terminal device 102 of information designating which circuit should be used. In another example, the terminal device 102 may notify the base station device 101 as capability information whether it has the capability to determine whether a separate circuit or a shared circuit should be used. If the terminal device 102 does not have that capability, the base station device 101 may notify the terminal device 102 of information designating which circuit should be used.

[0042] Furthermore, in the above example, an example in which two CCs are used has been described. However, when three or more CCs are used, information on the number of MIMO layers for each CC and information indicating the reception method can be similarly notified from the base station device 101 to the terminal device 102. In this case, too, if the reception method of the terminal device 102 is uniquely determined by the combination of the number of MIMO layers, information on the reception method does not need to be notified. Note that the base station device 101 may use the above-mentioned pattern information as information indicating the reception method. That is, for example, when pattern 1 is specified, it indicates that the received signals of all three CCs should be processed by a common shared circuit. Furthermore, when pattern 5 is specified, it indicates that the first to third CCs should each be processed by a separate circuit.

[0043] Furthermore, the base station device 101 may specify information indicating performance requirements that are expected to be satisfied in each CC and notify the terminal device 102. For example, when the base station device 101 communicates with the terminal device 102 using multiple CCs, the base station device 101 may notify the terminal device 102 of information indicating that signals are transmitted so that the above-mentioned performance requirement B is satisfied. Furthermore, when the base station device 101 communicates with the terminal device 102 using separate CCs with other base station devices that are located at different positions from the base station device 101 (at least located outside a predetermined distance range from the base station device 101), the base station device 101 may notify the terminal device 102 of information indicating that signals are transmitted so that the above-mentioned performance requirement A is satisfied. Also, in one example, when the base station device 101 provides a communication service by a first CC by a first Transmission and Reception Point (TRP) and provides a communication service by a second CC by a second TRP, the base station device 101 can notify the terminal device 102 of information indicating that signals are transmitted so as to satisfy the above-mentioned performance requirement A. That is, when the distance between the antennas of the signal transmitters in each CC is equal to or greater than a predetermined distance, the base station device 101 can notify the terminal device 102 of information indicating that signals are transmitted so as to satisfy performance requirement A, and when the distance is not greater than the predetermined distance, the base station device 101 can notify the terminal device 102 of information indicating that signals are transmitted so as to satisfy performance requirement B.

[0044] When the terminal device 102 is notified of such performance requirement information, it selectively uses either a demultiplexing circuit or a shared circuit so as to be able to communicate with sufficient quality when communication is performed under those performance requirements. For example, when the terminal device 102 receives notification that signals are transmitted so as to satisfy the above-mentioned performance requirement A, it receives signals using a configuration that can tolerate the magnitude of the reception timing difference, reception power difference, etc. between CCs defined as the performance requirement. For example, the terminal device 102 receives signals transmitted on each CC under performance requirement A by using a demultiplexing circuit or a signal processing circuit that makes communication under the performance requirement acceptable. Furthermore, when the terminal device 102 receives notification that signals are transmitted so as to satisfy the above-mentioned performance requirement B, it can determine that the differences in the reception timing difference, reception power difference, etc. between signals transmitted from each of the multiple CCs are small. For this reason, the terminal device 102 can communicate using, for example, a shared circuit. In addition, when a separate circuit is available, the terminal device 102 may decide to use a shared circuit when it is important to reduce power consumption and prioritize it, and to use a separate circuit when it is prioritized to execute communication for each CC with higher accuracy.

[0045] Assume that the base station device 101 provides communication services using both the first CC and the second CC and receives information such as that shown in FIG. 10B from the terminal device 102. In this case, the base station device 101 can assume that the reception timing difference and reception power difference between the signals of the two CCs at the terminal device 102 are sufficiently small, and therefore can assume that performance requirement B is met. Therefore, the base station device 101 can determine, for example, to use 4×4 MIMO for both the first CC and the second CC. In this case, the base station device 101 can notify the terminal device 102 of information specifying the number of MIMO layers for the first CC (maxMIMO-Layers) = 4, the number of MIMO layers for the second CC = 4, and performance requirement = B (performance requirement B). Furthermore, when the base station device 101 determines to use 2×2 MIMO for both the first CC and the second CC under the same conditions, it can notify the terminal device 102 of information specifying that the number of MIMO layers for the first CC is 2, the number of MIMO layers for the second CC is 2, and performance requirement B. In other words, since performance requirement B is satisfied regardless of the number of MIMO layers, this information can be notified to the terminal device 102. In this case, the terminal device 102 can independently determine whether to use a separation circuit capable of receiving processing even under performance requirement A, or a shared circuit capable of receiving processing under performance requirement B. Note that the base station device 101 may not notify information about the performance requirement when allowing the terminal device 102 to independently determine whether to use a separation circuit or a shared circuit.

[0046] 9A to 9C from the terminal device 102, the base station device 101 may use information on performance requirements for specifying whether the terminal device 102 should use a demultiplexing circuit or a shared circuit. For example, when the base station device 101 receives information such as that shown in FIG. 9B from the terminal device 102, the base station device 101 may notify the terminal device 102 that a demultiplexing circuit should be used by transmitting to the terminal device 102 information specifying that the number of MIMO layers of the first CC is 2, the number of MIMO layers of the second CC is 2, and performance requirement is A. Furthermore, when the base station device 101 receives information such as that shown in FIG. 9B from the terminal device 102, the base station device 101 may notify the terminal device 102 that a shared circuit should be used by transmitting to the terminal device 102 information specifying that the number of MIMO layers of the first CC is 2, the number of MIMO layers of the second CC is 2, and performance requirement is B.

[0047] On the other hand, when the base station device 101 provides a communication service using a first CC and another base station device provides a communication service using a second CC, it can be assumed that the difference in reception timing and reception power between the signals of the two CCs will be large at the terminal device 102. For this reason, it can be assumed that the base station device 101 will be able to communicate within the range of performance requirement A, without satisfying performance requirement B. In this case, the base station device 101 may determine, for example, to use 2×2 MIMO in both the first CC and the second CC. Then, the base station device 101 may notify the terminal device 102 of information specifying the number of MIMO layers for the first CC = 2, the number of MIMO layers for the second CC = 2, and performance requirement = A. In these cases, if the reception configuration of the terminal device 102 is uniquely determined solely by the number of MIMO layers in each CC, information on the performance requirements does not need to be notified to the terminal device 102. For example, when 4x4 MIMO is used in both the first CC and the second CC, the base station device 101 recognizes that performance requirement B must be met, and by specifying such a MIMO configuration, it is estimated that performance requirement B is met.

[0048] In the above example, an example in which two CCs are used has been described. However, when three or more CCs (carriers) are used, information on the number of MIMO layers for each CC and information indicating the performance requirements can be similarly notified from the base station device 101 to the terminal device 102. For example, when all three CCs are provided from the same base station device, it is expected that the reception timing difference and reception power difference between the signals of the three CCs will be sufficiently small. Therefore, the base station device 101 can instruct the terminal device 102 to process all signals received from the three CCs using a common shared circuit. In this case, the base station device 101 may notify the terminal device of information indicating that signals will be transmitted so that all signals of the three CCs satisfy performance requirement B. Furthermore, when the first CC and the second CC are provided from the same base station device and the third CC is provided from another base station device located in a different location, it is assumed that the difference in reception timing and reception power between the first CC and the second CC signals will be sufficiently small, and that the difference in reception timing and reception power between the third CC and the first CC and the third CC and the second CC signals will be large. Therefore, the base station device 101 may instruct the terminal device 102 to process the first CC and the second CC using a shared circuit and process the third CC using a separate circuit. In this case, the base station device 101 may notify the terminal device 102 of information indicating that the signals from the first CC and the second CC are transmitted so as to satisfy performance requirement B, and the signals from the third CC are transmitted so as to satisfy performance requirement A. Furthermore, when the first CC and the third CC are provided from the same base station device and the second CC is provided from another base station device located in a different location, it is assumed that the difference in reception timing and reception power between the signals of the first CC and the third CC will be sufficiently small, and that the difference in reception timing and reception power between the signals of the second CC and the first CC, and between the signals of the second CC and the third CC, will be large. For this reason, the base station device 101 can instruct the terminal device 102 to process the first CC and the third CC using a shared circuit and to process the second CC using a separate circuit.In this case, the base station device 101 may notify the terminal device 102 of information indicating that the signals from the first CC and the third CC are transmitted so that they satisfy performance requirement B, and the signals from the second CC are transmitted so that they satisfy performance requirement A. Furthermore, when the second CC and the third CC are provided from the same base station device and the first CC is provided from another base station device located in a different location, it is expected that the reception timing difference and reception power difference between the signals of the second CC and the third CC will be sufficiently small, and that the reception timing difference and reception power difference between the signals of the first CC and the second CC, and the first CC and the third CC, will be large. For this reason, the base station device 101 may instruct the terminal device 102 to process the second CC and the third CC using a shared circuit and to process the first CC using a separate circuit. In this case, information indicating that the signals from the second CC and the third CC are transmitted so that performance requirement B is satisfied, and that the signal from the first CC is transmitted so that performance requirement A is satisfied, can be notified from the base station device 101 to the terminal device 102. Furthermore, if the first CC to the third CC are all provided from different base station devices located in different locations, it is expected that the differences in reception timing and reception power of all signals will become large. For this reason, the base station device 101 can instruct the terminal device 102 to process the first CC to the third CC using respective separation circuits. In this case, information indicating that the signals from the first CC to the third CC are transmitted so that performance requirement A is satisfied for each other can be notified from the base station device 101 to the terminal device 102.

[0049] Furthermore, information on the performance requirements satisfied by the first CC to the third CC may be defined as a pattern, and information on which pattern should be used may be notified from the base station device 101 to the terminal device 102. In the above example, a pattern (pattern 1) in which all three CC signals are transmitted so as to satisfy performance requirement B, a pattern (pattern 2) in which the third CC signal is transmitted so as to satisfy performance requirement A so that the first CC and second CC signals satisfy performance requirement B, a pattern (pattern 3) in which the second CC signal is transmitted so as to satisfy performance requirement A so that the first CC and third CC signals satisfy performance requirement B, a pattern (pattern 4) in which the first CC signal is transmitted so as to satisfy performance requirement A so that the second CC and third CC signals satisfy performance requirement B, and a pattern (pattern 5) in which the first CC to third CC signals are transmitted so as to satisfy performance requirement A in all combinations may be defined. The base station device 101 can then notify the terminal device 102 of information on the pattern in which the signal will be transmitted (how the terminal device 102 should perform reception processing).

[0050] In this case, too, when the reception configuration of the terminal device 102 is uniquely determined by the combination of the number of MIMO layers, information regarding the performance requirements does not need to be notified. Also, here, an example has been described in which each CC is treated equally when three CCs are used, but some combinations of CCs may be treated differently from other CCs. For example, different treatment may be performed depending on the Radio Access Technology (RAT) used for each CC. For example, when three frequency band CCs, B42 (LTE: 3.5 GHz band), n77L (NR: 3.8 GHz-4.1 GHz), and n77H (NR: 3.9 GHz-4.2 GHz), are used, n77L and n77H are assumed to transmit signals from a single NR base station device (same location) due to NR carrier aggregation, and therefore, communication between them may always be treated as satisfying performance requirement B. On the other hand, since B42 is a carrier wave used by LTE base station devices, signals transmitted by that carrier wave may be transmitted from a different location than NR base station devices, and it may not be appropriate to treat it as always satisfying performance requirement B. For this reason, the base station device 101 does not transmit any special instructions for n77L and n77H, but may transmit information to the terminal device 102 that can identify whether a shared circuit or a separate circuit should be used for B42. The terminal device 102 then always performs reception processing of signals on CCs n77L and n77H using the shared circuit, and for reception processing of signals on CC B42, it may selectively use either the shared circuit or the separate circuit according to instructions from the base station device 101.

[0051] For example, when starting dual connectivity or carrier aggregation, the base station device 101 transmits an RRC Reconfiguration message to the terminal device 102. Note that RRC is an abbreviation for Radio Resource Control. The base station device 101 receives the above-mentioned UE Capability information and, based on that information, can notify the terminal device 102 of the configuration of CCs to be used by the terminal device 102 (information such as the number of MIMO layers) using this RRC Reconfiguration message. The terminal device 102 receives SpCellConfig and SCellConfig from the base station device 101, which include information on CCs to be used for dual connectivity or carrier aggregation. That is, SpCellConfig is received for CCs on which uplink signals are transmitted, and SCellConfig is received for CCs on which uplink signals are not transmitted. SpCellConfig and SCellConfig each include the maximum number of MIMO layers (maxMIMO-Layers) and information on the carrier frequency of the CC (frequencyInfoDL). In this embodiment, in addition to these two pieces of information, information on performance requirements for signals received in the terminal device 102 between CCs used in dual connectivity or carrier aggregation, and information such as the circuit configuration to be used can be specified. For example, when the base station device 101 determines that two CCs should be processed by a shared circuit, SpCellConfig and SCellConfig including frequencyInfoDL specifying the respective frequencies of these two CCs, maxMIMO-Layers specifying the maximum number of MIMO layers for each CC, and information specifying whether a shared circuit or a separate circuit should be used when these CCs are used can be notified from the base station device 101 to the terminal device 102. Note that the information specifying whether a shared circuit or a separate circuit should be used when multiple CCs are used may be specified by an information element separate from SpCellConfig and SCellConfig.Furthermore, as described above, instead of information specifying whether a shared circuit or a separate circuit should be used when multiple CCs are used, information on performance requirements may be included in the RRC Reconfiguration message and transmitted.

[0052] FIG. 11 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 1101, a ROM 1102, a RAM 1103, a storage device 1104, and a communication circuit 1105. The processor 1101 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 control processing of the device and the above-mentioned processes by reading and executing programs stored in the ROM 1102 or the storage device 1104. The ROM 1102 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 102. The RAM 1103 functions as a workspace when the processor 1101 executes a program and is also a random access memory that stores temporary information. The storage device 1104 is configured, for example, by a removable external storage device. The communication circuit 1105 is configured, for example, with circuits for wireless communication of LTE, 5G, and successor standards. While FIG. 11 illustrates one communication circuit 1105, 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 LTE, 5G, and successor standards, 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 1105 for each of a plurality of usable frequency bands, or may have a common communication circuit 1105 for at least some of these frequency bands. The communication circuit 1105 of the terminal device 102 includes the configurations shown in Figures 2 to 4.

[0053] FIG. 12 shows an example of the functional configuration of the terminal device 102. The terminal device 102 includes, for example, a capability information notification unit 1201 and a communication control unit 1202. Note that FIG. 12 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 102 compliant with LTE, 5G, and subsequent standards generally have. The functional blocks in FIG. 12 are shown only schematically, and the respective functional blocks may be integrated or further subdivided. Each function in FIG. 12 may be realized, for example, by the processor 1101 executing a program stored in the ROM 1102 or the storage device 1104, or may be realized, for example, by a processor within the communication circuit 1105 executing predetermined software. A storage medium storing a program for implementing this function may also be provided. 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.

[0054] The capability information notifying unit 1201 notifies the base station device 101 of information on combinations of the number of MIMO layers for multiple CCs that the terminal device 102 can use, as described above, and information indicating the configuration to be used in the terminal device 102 or the performance requirements that processable signals should satisfy when the number of MIMO layers indicated by the combination is used in each of the multiple CCs. The capability information notifying unit 1201 notifies the base station device 101, for example, of UE Capability including the above-mentioned FeatureSetsPerBands. Based on the information notified to the base station device 101 by the capability information notifying unit 1201, the communication control unit 1202 receives, from the base station device 101, control information on the configuration of the CCs to be used for communication (such as the number of MIMO layers and information that can specify whether a separation circuit or a shared circuit should be used in the communication). The communication control unit 1202 can receive the control information, for example, by the above-mentioned RRC Reconfiguration message, etc. The communication control unit 1202 performs reception processing of signals transmitted in multiple CCs in accordance with the control information.

[0055] FIG. 13 shows an example of the functional configuration of the base station device 101. The base station device 101 includes, for example, a capability information receiving unit 1301, a configuration determining unit 1302, and a configuration notifying unit 1303. Note that FIG. 13 only shows functions particularly related to this embodiment, and omits other functions that the base station device 101 may have. For example, the base station device 101 naturally has other functions that are generally possessed by base station devices 101 that comply with LTE, 5G, and subsequent standards. The functional blocks in FIG. 13 are shown schematically, and the respective functional blocks may be integrated or further subdivided. Each function in FIG. 13 may be realized, for example, by the processor 1101 executing a program stored in the ROM 1102 or the storage device 1104, or by a processor within the communication circuit 1105 executing predetermined software. A storage medium storing a program for implementing the function may also be provided. Since the details of the processes executed by each functional unit have been described above, only the general functions of the base station device 101 will be outlined here.

[0056] The capability information receiving unit 1301 receives capability information transmitted from the capability information notifying unit 1201 of the terminal device 102. The configuration determining unit 1302 determines a combination of the number of MIMO layers to be used in each CC in communication with the terminal device 102 based on the information received by the capability information receiving unit 1301. Furthermore, the configuration determining unit 1302 may determine whether the terminal device 102 should use a separation circuit or a shared circuit in communication with a combination of the number of MIMO layers to be used in each CC, or may specify performance requirements when signals of each CC are received by the terminal device 102. The configuration determining unit 1302 may specify the circuit to be used and the performance requirements depending on, for example, whether each CC is provided only by its own device or by its own device and another base station device, or may perform such specification based on measurement results in the terminal device 102 of signals from each CC. Furthermore, the configuration determination unit 1302 may identify the circuit to be used and performance requirements according to the measurement results using the antenna of the transmission source of each CC of the signal transmitted from the terminal device 102, the setting value of the timing advance value, etc. The configuration notification unit 1303 notifies the terminal device 102 of the configuration determined by the configuration determination unit 1302.

[0057] An example of the flow of processing executed in a wireless communication system is shown in Fig. 14. Note that, since the details of each process are as described above, only an overview of the processing flow will be given here, and detailed description will not be repeated.

[0058] In this processing example, first, the terminal device 102 transmits capability information (UE Capability) to the base station device 101, the capability information including information on combinations of the number of MIMO layers that the terminal device 102 can use for a plurality of CCs, as described above, and information indicating the configuration to be used in the terminal device 102 or the performance requirements that must be satisfied for processable signals when the number of MIMO layers indicated by the combinations is used in each of the plurality of CCs (S1401). The base station device 101 determines the combination of the number of MIMO layers to be used in each CC in communication with the terminal device 102 based on the capability information (S1402). Note that, in S1402, the base station device 101 may optionally specify whether the terminal device 102 should use a separation circuit or a shared circuit in communication with the combination of the number of MIMO layers to be used in each CC, or the performance requirements when the signal of each CC is received by the terminal device 102. Then, the base station device 101 transmits to the terminal device 102 an RRC Reconfiguration message including information on performance requirements related to the received signals at the terminal device 102 between CCs used in dual connectivity or carrier aggregation determined in S1402, and information on configurations such as the circuit configuration to be used (S1403). The terminal device 102 starts reception processing with a combination of the number of MIMO layers to be used in multiple CCs based on the notified configuration information (S1404). Here, the terminal device 102 may perform reception processing using, for example, a circuit configuration (separate circuit or shared circuit) specified by the base station device 101, or may perform reception processing using a circuit configuration determined by the combination of the number of MIMO layers. Furthermore, when both a separate circuit and a shared circuit are available, the terminal device 102 may select and use either one.

[0059] As described above, in this embodiment, the number of MIMO layers to be used in each CC in dual connectivity or carrier aggregation can be specified according to the configuration and performance of the receiving circuit of the terminal device 102. As a result, the base station device 101 can perform communication by appropriately selecting the MIMO configuration of each CC according to the capability of the terminal device 102. This makes it possible to contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which is to "build resilient infrastructure, promote sustainable industrialization, and foster innovation."

[0060] 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.

[0061] This application claims priority based on Japanese Patent Application No. 2024-126122, filed August 1, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A terminal device comprising: notification means for notifying a base station device to which it is connected of capability information of the terminal device, the capability information including: information indicating, for each combination of component carriers (CCs) used in dual connectivity or carrier aggregation, a combination of the number of layers of multi-input multi-output (MIMO) for each of a plurality of CCs that the terminal device can use, for each combination of CCs used in dual connectivity or carrier aggregation; and information on performance requirements including at least one of a reception timing difference and a reception power difference that must be satisfied by a received signal at the terminal device for each of the plurality of CCs, in order to enable the terminal device to receive signals of the plurality of CCs with a predetermined quality when MIMO with the number of layers indicated by the combination is used for each of the plurality of CCs; and control means for receiving from the base station device control information including information on the number of layers of MIMO used in the plurality of CCs, and controlling reception processing of signals in the plurality of CCs based on the control information.

2. The terminal device according to claim 1, wherein the information on the performance requirement is information indicating at least one of the reception timing difference and the reception power difference that can obtain a predetermined throughput value as the predetermined quality.

3. The terminal device of claim 1, wherein the information on performance requirements includes information on the performance requirements when receiving processing for each signal of the multiple CCs is performed using a shared circuit that shares some of the circuits, and information on the performance requirements when receiving processing for each signal of the multiple CCs is performed using separate circuits that are different circuits.

4. The terminal device according to claim 1, wherein the notification means notifies the base station device of the information on the performance requirements using FeatureSetsPerBands in UE Capability.

5. The terminal device of claim 1, wherein the control information further includes information indicating whether the terminal device should perform reception processing for each signal of the multiple CCs using a shared circuit that shares some of the circuitry, or whether the reception processing should be performed using separate circuits that are different circuits.

6. The terminal device according to claim 1, wherein the control information further includes information regarding requirements to be satisfied by at least one of the reception timing difference and reception power difference of the received signals at the terminal device for each signal of the plurality of CCs.

7. The terminal device according to claim 1, wherein the control means receives the control information by an RRC Reconfiguration message.

8. A base station apparatus comprising: a receiving means for receiving from the terminal apparatus capability information of a connected terminal apparatus, the capability information including: information indicating, for each combination of component carriers (CCs) used in dual connectivity or carrier aggregation, a combination of the number of multi-input multi-output (MIMO) layers in each of a plurality of CCs that the terminal apparatus can use, for each combination of CCs used in dual connectivity or carrier aggregation; and information on performance requirements including at least one of a reception timing difference and a reception power difference that must be satisfied by a received signal in the terminal apparatus for each of the plurality of CCs, in order to enable the terminal apparatus to receive signals of the plurality of CCs with a predetermined quality when MIMO with the number of layers indicated by the combination is used in each of the plurality of CCs; a determining means for determining a configuration of the number of MIMO layers to be used in the plurality of CCs based on the capability information; and a notifying means for notifying the terminal apparatus of control information including the determined configuration.

9. The base station device according to claim 8, wherein the information on the performance requirement is information indicating at least one of the reception timing difference and the reception power difference that can obtain a predetermined throughput value as the predetermined quality.

10. The base station device of claim 8, wherein the information on performance requirements includes information on the performance requirements when receiving processing for each signal of the multiple CCs is performed using a shared circuit that shares some of the circuits, and information on the performance requirements when receiving processing for each signal of the multiple CCs is performed using separate circuits that are different circuits.

11. The base station apparatus according to claim 8, wherein said receiving means receives information about said performance requirements included in FeatureSetsPerBands in UE Capability.

12. The base station device of claim 8, wherein the control information further includes information indicating whether the terminal device should perform reception processing for each signal of the plurality of CCs using a shared circuit that shares some of the circuitry, or whether the reception processing should be performed using separate circuits that are different circuits.

13. The base station device according to claim 8, wherein the control information further includes information on requirements to be satisfied by at least one of the reception timing difference and reception power difference of the received signals at the terminal device for each signal of the plurality of CCs.

14. The base station device according to claim 8, wherein the determination means determines the number of MIMO layers to be used in the plurality of CCs based on whether or not each of the signals of the plurality of CCs is transmitted from a different antenna located at a position that is at least a predetermined distance apart.

15. The base station device according to claim 8, wherein the determining means determines the number of MIMO layers to be used in the plurality of CCs based on measurement results of the signals of the plurality of CCs in the terminal device.

16. The base station device according to claim 8, wherein the determination means determines the number of MIMO layers to be used in the plurality of CCs based on measurement results of signals transmitted from the terminal device at antennas from which the plurality of CCs are transmitted.

17. The base station apparatus according to claim 8, wherein the notification means notifies the terminal apparatus of the control information by an RRC Reconfiguration message.

18. A control method executed by a terminal device, comprising: notifying a base station device to which the terminal device is connected of capability information of the terminal device, the capability information including: information indicating, for each combination of component carriers (CCs) used in dual connectivity or carrier aggregation, a combination of the number of multi-input multi-output (MIMO) layers for each of a plurality of CCs that the terminal device can use, for each combination of CCs used in dual connectivity or carrier aggregation; and information on performance requirements including at least one of a reception timing difference and a reception power difference that must be satisfied by received signals for each of the plurality of CCs in the terminal device, in order to enable the terminal device to receive signals of the plurality of CCs with a predetermined quality when MIMO with the number of layers indicated by the combination is used for each of the plurality of CCs; and receiving control information from the base station device including information on the number of MIMO layers used in the plurality of CCs, and controlling reception processing of signals in the plurality of CCs based on the control information.

19. A control method executed by a base station device, comprising: receiving capability information of a connected terminal device, the capability information including: information indicating, for each combination of component carriers (CCs) used in dual connectivity or carrier aggregation, a combination of the number of multi-input multi-output (MIMO) layers for each of a plurality of CCs that the terminal device can use, and performance requirement information including at least one of a reception timing difference and a reception power difference that must be satisfied by received signals for each of the plurality of CCs, in order to enable the terminal device to receive signals of the plurality of CCs with a predetermined quality when MIMO with the number of layers indicated by the combination is used for each of the plurality of CCs; determining a configuration of the number of MIMO layers to be used for the plurality of CCs based on the capability information; and notifying the terminal device of control information including the determined configuration.

20. A program for causing a computer to function as each of the means possessed by the terminal device according to any one of claims 1 to 7.

21. A program for causing a computer to function as each of the means possessed by the base station device according to any one of claims 8 to 17.

Images