Terminal and communication method

Abstract

Provided is a terminal that can appropriately execute uplink transmission switching. This terminal comprises: a reception unit that receives, from a base station, configuration information related to switching in a switching scheme in which three or more bands to be used for transmission can be configured and two ports can be switched between the bands; and a control unit that, when only two bands are configured to be used in the configuration information, determines whether to perform transmission switching for switching between transmission using one of the two bands at only one of the two ports and transmission using the other of the two bands at only the other of the two ports, or not to perform the transmission switching.

Description

Terminal and communication method

[0001] The present disclosure relates to a terminal and a communication method.

[0002] For NR (New Radio) (also known as "5G"), the successor system to LTE (Long Term Evolution), technologies are being considered that meet the requirements of a large-capacity system, high-speed data transmission speed, low latency, simultaneous connection of a large number of terminals, low cost, and low power consumption.

[0003] Furthermore, in Release 18 (Rel-18) of 3GPP (registered trademark), it is possible to set three or four bands as bands that can be used for UL transmission, and a scheme is being considered in which the band for transmission is dynamically switched from among these bands to support simultaneous transmission using up to two bands (UL Tx switching schemes across up to three or four bands with restriction of up to two Tx simultaneous) (for example, Non-Patent Documents 1, 2, and 3).

[0004] “New WID on Multi-carrier enhancements”, RP-213577, 3GPP TSG RAN Meeting #94e, 3GPP, December 2021 “Summary#4 of discussion on Multi-carrier UL Tx switching scheme”, R1-2310677, 3GPP TSG RAN WG1 #114bis, 3GPP, October 2023 “Maintenance on Multi-carrier UL Tx switching scheme”, R1-2309503, 3GPP TSG RAN WG1 #114bis, 3GPP, October 2023

[0005] In the case where the number of bands available for UL transmission is two, if one port transmission (single-port transmission) is instructed in one of the bands, there may be two possible band combinations (ambiguous state issue).To solve this problem, a parameter (uplinkTxSwitching-DualUL-TxState) is introduced to specify whether one transmission (1Tx) is assumed for each band or two transmissions (2Tx) are assumed in the band where transmission is performed.

[0006] However, when the number of bands available for UL transmission increases to three or four, the number of band combinations to be used for UL transmission also increases. Therefore, even if the above-mentioned parameter (uplinkTxSwitching-DualUL-TxState) is used, an ambiguous state issue is expected in which there are still two or more candidate band combinations.

[0007] In this way, it is possible to set three or four bands as bands that can be used for UL transmission, but cases are also envisaged in which UL Tx switching (UL transmission switching) is performed between two bands.

[0008] However, when three or four (or more) bands can be set as bands that can be used for UL transmission, there has been insufficient consideration of how to perform UL Tx switching between two bands. Unless the operation of such UL Tx switching is clarified, there is a risk that communication cannot be performed appropriately due to performance degradation, etc.

[0009] One aspect of the present disclosure provides a terminal and a communication method capable of appropriately performing UL transmission switching.

[0010] A terminal according to one aspect of the present disclosure includes a receiver that receives, from a base station, configuration information regarding switching in a switching method in which two ports can be switched between a maximum of three or more settable bands to be used for transmission, and a controller that, when only two bands are set as bands to be used in the configuration information, performs transmission switching that switches between transmission using one of the two bands using only one of the two ports and transmission using the other of the two bands using only the other of the two ports, or determines not to perform the transmission switching.

[0011] 1 is a diagram illustrating an example of a wireless communication system according to an embodiment of the present disclosure. FIG. 1 is a diagram illustrating an example of a frequency range used in the wireless communication system according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating example configurations of radio frames, subframes, and slots used in the wireless communication system according to an embodiment of the present disclosure. FIG. 3 is a diagram illustrating Case 1 and Case 2 in UL Tx switching. FIG. 4 is a diagram illustrating example configurations of antenna ports used for transmission in each case of UL Tx switching. FIG. 5 is a diagram illustrating an example of UE capability. FIG. 6 is a diagram illustrating an example of an RRC configuration. FIG. 7 is a diagram illustrating an example of a switching period. FIG. 8 is a diagram illustrating an example of a switching period. FIG. 9 is a diagram illustrating an example of a length of a DL interruption. FIG. 10 is a diagram illustrating Cases 1 to 3 in UL Tx switching. FIG. 11 is a diagram illustrating example configurations of antenna ports used for transmission in each case of UL Tx switching. FIG. 12 is a diagram illustrating an example of an RRC configuration. FIG. 13 is a diagram illustrating an example of a UL Tx switching case where one band includes multiple carriers. FIG. 14 is a diagram illustrating example configurations of antenna ports used for transmission in each case of UL Tx switching. FIG. 15 is a diagram illustrating an example configuration when switching is performed across four bands. FIG. 16 is a diagram illustrating an example configuration of antenna ports used for transmission when switching is performed across four bands. FIG. 1 is a diagram showing an example of switching when switching is performed across four bands. FIG. 2 is a diagram showing an example of switching when switching is performed across four bands. FIG. 3 is a diagram showing an example of switching when switching is performed across four bands according to the present embodiment. FIG. 4 is a diagram showing an example of modification of specifications according to the present embodiment. FIG. 5 is a diagram showing an example of modification of specifications according to the present embodiment. FIG. 6 is a diagram showing an example of switching when switching is performed across four bands according to the present embodiment.FIG. 1 is a diagram illustrating a modified example of specifications according to the present embodiment. FIG. 2 is a diagram illustrating a modified example of specifications according to the present embodiment. FIG. 3 is a flowchart illustrating an example of an operation of a terminal according to the present embodiment. FIG. 4 is a block diagram illustrating an example of a configuration of a base station according to the present embodiment. FIG. 5 is a block diagram illustrating an example of a configuration of a terminal according to the present embodiment. FIG. 6 is a diagram illustrating an example of a hardware configuration of a base station and a terminal according to an embodiment of the present disclosure. FIG. 7 is a diagram illustrating an example of a configuration of a vehicle in an embodiment of the present disclosure.

[0012] Hereinafter, an embodiment according to one aspect of the present disclosure will be described with reference to the drawings.

[0013] 1 is a diagram illustrating an example of a wireless communication system 1 according to an embodiment of the present disclosure. The wireless communication system 1 is a wireless communication system conforming to 5G NR, and includes a Next Generation-Radio Access Network 2 (hereinafter, NG-RAN 2) and a terminal 20 (hereinafter, also referred to as UE (User Equipment) 20).

[0014] The wireless communication system 10 may be a wireless communication system conforming to a system called Beyond 5G, 5G Evolution, or 6G.

[0015] The NG-RAN2 includes a base station 10A (hereinafter also referred to as gNB 10A) and a base station 10B (hereinafter also referred to as gNB 10B). When it is not necessary to distinguish between the gNB 10A, the gNB 10B, etc., they are collectively referred to as gNBs or base stations 10. Furthermore, the number of gNBs and UEs is not limited to the example shown in FIG. 1.

[0016] NG-RAN2 actually includes multiple NG-RAN nodes, specifically, gNBs (or ng-eNBs), and is connected to a 5G core network (5GC, not shown). NG-RAN2 and 5GC may simply be referred to as "networks." In the following, gNB may be replaced with network (NW).

[0017] As an example, the gNB 10A and the gNB 10B are base stations conforming to 5G, and perform 5G wireless communication with the UE 20. The gNB 10A, the gNB 10B, and the UE 20 may support MIMO (Multiple-Input Multiple-Output), which generates a more directional beam BM by controlling radio signals transmitted from multiple antenna elements, carrier aggregation (CA), which uses a bundle of multiple component carriers (CC), and dual connectivity (DC), which performs communication between the UE and each of two NG-RAN nodes.

[0018] Furthermore, the wireless communication system 1 may be compatible with a plurality of frequency ranges (FR). Fig. 2 is a diagram showing an example of FRs used in the wireless communication system 1. As shown in Fig. 2, the wireless communication system 1 may be compatible with FR1 and FR2. The frequency bands of each FR are, for example, as follows: FR1: 410 MHz to 7.125 GHz FR2: 24.25 GHz to 52.6 GHz

[0019] FR1 may use a sub-carrier spacing (SCS) of 15 kHz, 30 kHz, or 60 kHz, and a bandwidth (BW) of 5 to 100 MHz. FR2 is a higher frequency than FR1, and may use an SCS of 60 kHz or 120 kHz (including 240 kHz), and a bandwidth (BW) of 50 to 400 MHz.

[0020] Note that SCS may be interpreted as numerology, which is defined in 3GPP TS 38.300 and corresponds to one subcarrier spacing in the frequency domain.

[0021] Furthermore, the wireless communication system 1 may support a frequency band higher than the FR2 frequency band. Specifically, the wireless communication system 1 may support a frequency band exceeding 52.6 GHz up to 114.25 GHz. For convenience, such a high frequency band may be referred to as "FR2x." When using a frequency band exceeding 52.6 GHz, CP-OFDM (Cyclic Prefix-Orthogonal Frequency Division Multiplexing) / DFT-S-OFDM (Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing) with a larger SCS may be applied.

[0022] 3 is a diagram showing an example of the configuration of a radio frame, subframe, and slot used in the radio communication system 1. As shown in FIG. 3, one slot is composed of 14 symbols, and the larger (wider) the SCS, the shorter the symbol period (and slot period). However, the SCS is not limited to the interval (frequency) shown in FIG. 3. For example, 480 kHz, 960 kHz, etc. may be used as the SCS.

[0023] Furthermore, the number of symbols constituting one slot does not necessarily have to be 14 (for example, it may be 28 or 56 symbols, etc.) Furthermore, the number of slots per subframe may differ depending on the SCS.

[0024] 3 may be called a time domain, a symbol period, a symbol time, etc. The frequency direction may be called a frequency domain, a resource block, a subcarrier, a bandwidth part (BWP), etc.

[0025] gNB10 transmits control information, setting information, etc. to UE20 as a downlink (DL) signal.

[0026] Furthermore, for example, gNB10 receives control information, data signals, information regarding the processing capabilities of UE20 (terminal capabilities (information); for example, UE capability), etc. from UE20 as uplink (UL) signals.

[0027] Channels used for transmitting DL signals include, for example, data channels and control channels. For example, the data channel may include a physical downlink shared channel (PDSCH), and the control channel may include a physical downlink control channel (PDCCH). For example, the gNB 10 transmits control information to the UE 20 using the PDCCH, and transmits DL data signals using the PDSCH. Note that the PDSCH is an example of a downlink shared channel, and the PDCCH is an example of a downlink control channel. Note that the PDCCH may be interpreted as downlink control information (DCI), control information, etc. transmitted in the PDCCH.

[0028] The reference signal included in the DL signal may include, for example, at least one of a DMRS (Demodulation Reference Signal), a PTRS (Phase Tracking Reference Signal), a CSI-RS (Channel State Information - Reference Signal), an SRS (Sounding Reference Signal), and a PRS (Positioning Reference Signal) for position information. For example, reference signals such as the DMRS and PTRS are used to demodulate the DL data signal and are transmitted using the PDSCH.

[0029] The UE 20 is a communication device equipped with a wireless communication function, such as a smartphone, a mobile phone, a tablet, a wearable device, or an M2M (Machine-to-Machine) communication module.

[0030] UE 20 receives control signals or data signals from gNB 10 in DL and transmits control signals or data signals to gNB 10 in UL, thereby utilizing various communication services provided by wireless communication system 1. UE 20 also receives various reference signals transmitted from gNB 10 and performs measurement of propagation path quality based on the reception results of the reference signals.

[0031] For example, UE20 receives control information, configuration information, etc. from gNB10 as a DL signal.

[0032] Also, for example, UE20 transmits control information, data signals, terminal capability information of UE20, etc. to gNB10 as UL signals.

[0033] Channels used for transmitting UL signals include, for example, data channels and control channels. For example, the data channel may include a Physical Uplink Shared Channel (PUSCH), and the control channel may include a Physical Uplink Control Channel (PUCCH). For example, the UE 20 transmits control information using the PUCCH and transmits UL data signals using the PUSCH. Note that the PUSCH is an example of an uplink shared channel, and the PUCCH is an example of an uplink control channel. Note that the PUSCH or the PUCCH may be interpreted as uplink control information (UCI), control information, etc. transmitted in the PUSCH or the PUCCH.

[0034] The reference signal included in the UL signal may include, for example, at least one of a DMRS, a PTRS, a CSI-RS, an SRSRS, and a PRS for location information. For example, the reference signal such as the DMRS or the PTRS is used for demodulating the UL data signal and is transmitted using the PUSCH.

[0035] In the conventional technologies (Rel-16 and Rel-17), a UL Tx switching function (uplink transmission switching function) that can switch UL transmission between two bands (two carriers) is supported in the terminal 20. Even in a terminal 20 that has only two transmission chains, by using the UL Tx switching function, it is possible to perform operations such as transmitting using two antenna ports for one carrier, or transmitting using one antenna port for one carrier and another antenna port for another carrier by switching over time.

[0036] The transmission chain is a physical function for transmission in the terminal 20, regardless of whether actual transmission is performed or not. Transmission can be performed using one carrier using one transmission chain. By switching the carrier used by the transmission chain (the transmission function unit corresponding to the carrier), the carrier that can be transmitted using the transmission chain can be switched.

[0037] An antenna port is an antenna that can actually transmit using a transmit chain. The terms transmit chain and antenna port are sometimes used synonymously. Also, an "antenna port" may be referred to as a "port."

[0038] In the following description, unless otherwise specified, one band has one carrier. Therefore, "band" may be replaced with "carrier" and "carrier" may be replaced with "band". However, having one carrier in one band is an example, and one band may have multiple carriers. When one band has multiple carriers, the number and relationship of the carriers may be limited, for example, to two carriers that are consecutive in frequency. Multiple carriers in one band may be treated the same as one UL band (carrier) in the following description.

[0039] 3GPP is considering "UL Tx switching schemes across up to 3 or 4 bands with restriction of up to 2 Tx simultaneous transmission for FR1 UEs" (a function that enables a terminal that supports up to two simultaneous transmissions in FR1 to dynamically switch the band in which UL transmission is performed across three or four bands). For convenience, this function may be called "Rel-18 UL Tx switching."

[0040] The above function enables a terminal that cannot perform UL CA (Carrier Aggregation) or can perform only up to two UL CAs to set three or four UL bands (carriers) and dynamically instruct the base station 10 to transmit in one or two of the UL bands (carriers).

[0041] This function makes it possible to instruct terminal 20 to perform UL transmission using a UL band (carrier) suitable for use in each time resource, taking into consideration the traffic conditions and TDD configuration among multiple UL bands (carriers), thereby improving frequency utilization efficiency and UL throughput.

[0042] Rel-16 and Rel-17 specify UL Tx switching between two bands. However, in Rel-18 UL Tx switching, it is not clear how to set the UL band (carrier) that is a candidate for switching to the terminal 20.

[0043] Conventionally, a terminal 20 supporting UL CA can configure multiple DL / UL carriers as serving cells with the number of CCs of the UL CA supported by the terminal 20, and dynamically specify the UL CC to be used for transmission. However, Rel-18 UL Tx switching requires configuring a number of UL carriers greater than the number of CCs of the UL CA supported by the UL CA. However, the conventional technology does not anticipate configuring a number of UL CCs greater than the supported number.

[0044] Another existing technology is supplemental uplink (SUL). The SUL framework supports linking with and dynamic switching to normal uplink (NUL), but the SUL framework is not intended to be extended.

[0045] In the following, we will first explain UL Tx switching for Rel-16 and Rel-17. Then, we will explain the proposal for Rel-18 UL Tx switching. Note that the Capabilities and configuration information specified for UL Tx switching for Rel-16 and Rel-17 may also be applied to Rel-18 UL Tx switching.

[0046] In addition, the UL Tx switching for Rel-16 and Rel-17 will be explained. Regarding power boosting, switching period, DL interruption, etc., the operation of these elements is basically the same in Rel-18 UL Tx switching as in Rel-16 and Rel-17.

[0047] (Rel-16 UL Tx switching) In Rel-16, the terminal 20 supports two carriers and has two transmission chains. One transmission chain is fixed to one carrier, but the other transmission chain can be linked to either of the two carriers using a switch. Therefore, for example, simultaneous transmission using two antenna ports on one carrier is possible. Also, each antenna port can transmit using one carrier and one antenna port. These methods can be dynamically switched. UL Tx switching in Rel-16 is called Rel-16 1Tx-2Tx switching.

[0048] As shown in FIG. 4, a configuration in which each transmission chain is linked to one carrier is called Case 1, and a configuration in which two transmission chains are linked to one carrier is called Case 2.

[0049] Fig. 5 shows the configuration of the transmission chains used for transmission in the SUL in Case 1 and Case 2. For example, 1T+1T in Case 1 means that, in the example of Fig. 4, carrier 2 is connected to transmission chain 1 and carrier 1 is connected to transmission chain 2.

[0050] Also, 1P+0P in the 1T+1T state means that transmission is performed using carrier 2 on antenna port 2, but no transmission is performed on antenna port 1. In SUL, two carriers cannot be configured simultaneously, so 1P+1P does not exist. Also, in SUL, transmission of only NUL (carrier 2) is not expected in case 1, so 0P+1P does not exist.

[0051] In addition, "0P+2P, 0P+1P" in case 2 means that transmission is performed using carrier 2 on antenna port 1 and antenna port 2, or transmission is performed using carrier 2 on antenna port 1 only.

[0052] Rel-16 1Tx-2Tx switching in inter-band CA / EN-DC has two options: Option 1, which does not allow two carriers to be used simultaneously, and Option 2, which allows two carriers to be used simultaneously. The transmission chain configuration used for transmission in Option 1 is the same as that shown in Figure 5. The transmission chain configuration used for transmission in Option 2 is as shown in Figure 6.

[0053] Fig. 7 shows an example of UE capability that is defined in accordance with Rel-16 1Tx-2Tx switching and that is reported from the terminal 20 to the base station 10. Fig. 8 shows an example of CellGroupConfig and ServingCellConfig that are defined in accordance with Rel-16 1Tx-2Tx switching and that are set in the terminal 20 by the base station 10.

[0054] The uplinkTxSwitchingPeriodLocation-r16 in the ServingCellConfig indicates whether a UL Tx switching period is configured in the target cell (carrier). Examples of operation related to the UL Tx switching period are shown in Figures 9 and 10. Figure 9 shows an example in which a UL Tx switching period is configured to occur in carrier 1. In this case, a UL Tx switching period occurs in carrier 1 in both cases of switching from carrier 1 to carrier 2 and switching from carrier 2 to carrier 1. For example, in the case of Figure 9, if the terminal 20 receives an instruction to switch to carrier 2 while transmitting on carrier 1, it will transmit on carrier 2 after the switching time on carrier 1. Figure 10 shows an example in which a UL Tx switching period is configured to occur in carrier 2.

[0055] When dynamically switching between the two carriers, the terminal 20 is allowed a DL interruption of a predetermined length in the DL carrier that overlaps with the UL switching period, the length of which (X OFDM symbols) is defined as shown in Figure 11.

[0056] Rel-16 UL Tx switching can be summarized as follows: Based on PUSCH scheduling (scheduling command, rank adaptation) from the base station 10, the terminal 20 can dynamically switch between "single-port transmission on carrier 1," "single-port transmission on carrier 2," "single-port transmission on carrier 1 + one-port transmission on carrier 2" (applicable only when option 2 is supported in interband CA), and "two-port transmission on carrier 2 (with or without 3 dB power boosting)."

[0057] A switching period occurs when the carrier connected to the transmission port is switched, and during the switching period, UL transmission is not performed on either carrier. Also, there are cases where a DL interruption occurs during the switching period.

[0058] (Rel-17 UL Tx switching) Next, Rel-17 UL Tx switching will be described. In Rel-17, each of two transmit chains can support two carriers, resulting in 2Tx-2Tx UL Tx switching. Since two-port transmission is also possible with carrier 1, compared to Rel-16, case 3 is added to cases 1 and 2 as connection patterns between transmit chains and carriers, as shown in FIG. 12 . Therefore, it is necessary for the terminal 20 and the base station 10 to distinguish between Rel-17 (2Tx-2Tx UL Tx switching) and Rel-16 (1Tx-2Tx UL 1Tx-2Tx switching).

[0059] In Rel-17 (2Tx-2Tx UL Tx switching), the pattern of the number of transmit ports in each case is as shown in Figure 13. Figure 13 shows the pattern of the number of transmit ports for each case and each option (whether simultaneous transmission of two carriers is possible or not).

[0060] Here, for example, when 1P+0P is instructed in case 2 for terminal 20 performing UL CA option 2, or when 0P+1P is instructed in case 3, terminal 20 must decide which of the remaining two cases to switch to.

[0061] Fig. 14 shows an example of RRC settings in Rel-17. In Fig. 13, uplinkTxSwitching-2T-Mode-r17 indicates a setting to switch to 2Tx-2Tx UL Tx switching mode, and uplinkTxSwitching-DualUL-TxState-r17 is information for setting which case to switch to when there are multiple candidates for which case to switch to at the time of switching, as described above.

[0062] In addition, in Rel-17 UL Tx switching, there are two bands, and one of the bands supports the use of two consecutive carriers, as shown in Figure 15. Examples of transmit port configurations for each case in the example of Figure 14 are shown in Figures 16 and 17.

[0063] The functions, setting values, specified values, etc. of Rel-16 and Rel-17 described above may be applied to Rel-18 UL Tx switching.

[0064] (Rel-18 UL Tx switching) Possible cases for Rel-18 UL Tx switching and the configuration of ports where transmission takes place in each case are shown in Figures 18 and 19. Here, as an example, the bands that can be used for UL Tx switching are four bands, Band A to Band D.

[0065] As shown in Figure 18, there are two transmit chains (two antenna ports), each of which can be switched to any of bands A to D. This is referred to as "2Tx-2Tx (-2Tx-2Tx) switching." Assuming that one carrier is available for each band, the maximum number of cases is 10, as shown in Figure 19 (assuming CA option 2).

[0066] In addition to the above assumptions, a case of 1Tx-2Tx (-1Tx-1Tx) switching, in which the band (carrier) that one port can use is fixed, can also be considered.

[0067] Furthermore, as shown in FIG. 15, there may be cases where there are two consecutive carriers in some bands (a total of five or more carriers).

[0068] Rel-18 UL Tx switching may also be referred to as a switching scheme in which two ports can switch between three or more bands (or across three or more bands) for transmissions in which two or fewer bands are used.

[0069] Rel-18 UL Tx switching also includes the case of 11T-1T (UL Tx) switching (also called 1Tx-1Tx (UL Tx) switching), which was not covered in Rel-16 and Rel-17. 1T-1T switching is a case where two carriers (bands) only support transmission from one port.

[0070] 1T-1T switching can be understood as switching between some of the configured bands when three or four bands (carriers) are configured. On the other hand, 1T-1T switching, which can be considered a subset of 1T-2T switching (1Tx-2Tx switching) and 2T-2T switching (2Tx-2Tx switching) in Rel-16 / Rel-17, is inherently possible, and it can also be understood that 1T-1T switching when configuring UL Tx switching of two bands using Rel-18 settings is not a problem.

[0071] Regarding 1T-1T switching, the following is being discussed in 3GPP, for example.

[0072] For example, it has been agreed in RAN2 that signaling in Rel-18 may configure dual-band UL Tx switching for band pairs supported by the terminal 20 in accordance with the Rel-18 band pair list terminal capability information (UE capability), and in this case, the NW and the terminal 20 assume that the terminal capability (information) reported for Rel-18 UL Tx switching is used (see R1-2400007).

[0073] Furthermore, for example, if signaling in Rel-18 allows configuring two bands for UL Tx switching, it is proposed that Rel-18 basically supports 1T-1T UL Tx switching between two bands (UL transmission at one port is configured for each band), and terminal 20 may perform this UL Tx switching using one transmission chain (see R1-2400500).

[0074] Furthermore, for example, as an exception to the agreement in RAN2, it has been agreed that discussions will continue regarding the case where Rel-18 UL Tx switching is configured for the band combination {A, B} for a terminal 20 that reports support for UL Tx switching for the band combination {A, B, C} / {A, B, C, D}, but UL MIMO is not supported in band A and band B (see R1-2401639).

[0075] <About the Issue> As described above, in Rel-18 UL Tx switching, the operation of a wireless communication system for UL Tx switching, including 1T-1T switching between two bands, has not been clarified. If this operation is not clarified, there is a risk of performance degradation due to misunderstandings between the terminal 20 and the base station 10 or unnecessary switching.

[0076] Therefore, the following describes proposals (Proposals 1 to 3) that clarify the operations related to UL Tx switching between two bands (for example, in Rel-18 UL Tx switching).

[0077] (Proposal 1) In Proposal 1, we propose to not allow a configuration that results in 1Tx-1Tx UL Tx switching between two bands, so that the Rel-18 UL Tx switching configuration can be used for both bands as is.

[0078] Therefore, the terminal 20 does not need to assume that a setting that results in 1Tx-1Tx UL Tx switching between two bands is made, and such a case (a setting that results in 1Tx-1Tx UL Tx switching between two bands) may be defined in the specifications as an error case.

[0079] As more specific examples of Proposal 1, the following Examples 1-1 and 1-2 are considered.

[0080] [Example 1-1] The RRC configuration for UL Tx switching of Rel-18 (uplinkTxSwitchingBandList-r18 in uplinkTxSwitchingMoreBands-r18) may be configured for only two UL bands only when the terminal 20 supports UL MIMO (transmission via two or more ports) in at least one of the two UL bands. The RRC configuration for UL Tx switching of Rel-18 may also be referred to as configuration information related to switching in a switching method in which two ports can be switched among a maximum of three or more settable bands used for transmission.

[0081] [Example 1-2] If the terminal 20 reports support for Rel-18 UL Tx switching for BCs of three or four UL bands, and two or more of these UL bands do not support UL MIMO (transmission over two or more ports), the terminal 20 does not (may not) support UL Tx switching that is set between only such two UL bands.

[0082] According to Proposal 1, even in a network that only supports the Rel-18 configuration, UL Tx switching between two bands can be configured.

[0083] (Proposal 2) In Proposal 2, we propose to allow a specific terminal 20 to have a setting that results in 1Tx-1Tx UL Tx switching between the two bands, so that the Rel-18 UL Tx switching setting can be used as is for the two bands.

[0084] For this purpose, the terminal 20 may define whether or not it supports the setting of 1Tx-1Tx UL Tx switching between the two bands as terminal capability (information) (UE capability), and may report the UE capability.

[0085] As a more specific example of Proposal 2, the following Example 2-1 can be considered.

[0086] [Example 2-1] The RRC setting for UL Tx switching of Rel-18 (uplinkTxSwitchingBandList-r18 in uplinkTxSwitchingMoreBands-r18) may be configured for only two UL bands when the terminal 20 supports UL MIMO (transmission with two or more ports) in at least one of the two UL bands, or when the terminal 20 does not support UL MIMO (transmission with two or more ports) in both of the two UL bands but supports a specific capability.

[0087] Here, a specific capability may have at least one of the following characteristics:

[0088] - Report compatibility for each band combination, band, or device.

[0089] - Rel-18 UL Tx switching must be supported, and the contents reported in the Capability indicating support for Rel-18 UL Tx switching, such as the switching period, will also apply to 1Tx-1Tx UL Tx switching between two UL bands.

[0090] - In a capability that is independent (different) from Rel-18 UL Tx switching, the switching period etc. that needs to be reported for UL Tx switching is reported. (In this case, Rel-18 UL Tx switching (three bands or four bands) may be supported, or Rel-18 UL Tx switching may not be supported.)

[0091] Supports at least some of the functions supported by terminals with RedCap or eRedCap capabilities. (This capability may be considered (positioned or interpreted) as giving RedCap terminals the UL Tx switching function. Also, this capability may be reported only when the supported bands, number of antennas, etc. meet the restrictions for RedCap terminals.)

[0092] According to Proposal 2, even in a network that only supports the Rel-18 configuration, UL Tx switching between two bands can be configured.

[0093] (Proposal 3) In Proposal 3, we propose to allow the configuration of 1Tx-1Tx UL Tx switching between the two bands, so that the Rel-18 UL Tx switching configuration can be used as is for the two bands.

[0094] To that end, the terminal 20 may take certain actions and / or assumptions when configured for 1Tx-1Tx UL Tx switching between the two bands.

[0095] As a more specific example of Proposal 3, the following Example 3-1 can be considered.

[0096] [Example 3-1] When the RRC configuration for Rel-18 UL Tx switching (uplinkTxSwitchingBandList-r18 in uplinkTxSwitchingMoreBands-r18) is configured for only two UL bands, the terminal 20 may perform and / or assume different operations than for 1Tx-1Tx UL Tx switching between two bands when three or four bands are configured.

[0097] The above settings may be applied only to terminals 20 that have a specific capability (see, for example, Proposal 1 or Proposal 2).

[0098] The terminal 20 may apply a specific value (e.g., 0 μs or a specific value defined in the specifications) as the switching period (different from a value that can be set in the RRC configuration) (may perform switching according to the specific value), and therefore may not apply the value reported in the Rel-18 UL Tx switching Capability.

[0099] According to Proposal 3, even in a network that only supports the Rel-18 configuration, UL Tx switching between two bands can be configured.

[0100] Regarding Rel-18 UL Tx switching, UL Tx switching (UL transmission switching) for cases where a terminal cannot perform UL transmission in a configured cell has also been studied (e.g., Non-Patent Documents 2 and 3), but due to the increase in the number of band combinations, there is a risk of performance degradation during such UL transmission switching. This will be explained in more detail below.

[0101] As mentioned above, an RRC parameter (uplinkTxSwitching-DualUL-TxState) is introduced to specify whether one transmission (1Tx) is assumed for each band or two transmissions (2Tx) are assumed in the bands where transmission is performed. The former is specified by oneT and the latter is specified by twoT via uplinkTxSwitching-DualUL-TxState.

[0102] In the case of dual UL, uplinkTxSwitching-DualUL-TxState is used to solve the ambiguous state issue where there are two or more band combination candidates, at least for the following cases 1 and 2.

[0103] Case 1: If two transmit chains are currently bound to one band (band A) and the next transmission is a 1-port transmission on another band (band B), there are several possible switching cases in which 1-port transmission on band B (1P on band B) is supported:

[0104] (1) If twoT is set, two transmission chains are switched to band B.

[0105] (2) When oneT is configured, one transmission chain is switched to band B, and the other transmission chain remains in band A. Figure 20 shows an example of switching in switching case (2).

[0106] Case 2: If two transmit chains are currently associated with two different bands (Band A and Band B) and the next transmission is a 1-port transmission on another band (Band C), there are several possible switching cases in which 1-port transmission on Band C (1P on Band C) is supported:

[0107] (3) If twoT is set, two transmission chains are switched to band C.

[0108] (4) When oneT is configured, one transmission chain is switched to band C, and if there is a band (associated band; also referred to as a tied band) tied to band C, the other transmission chain is switched to the tied band. FIG. 21 shows a switching example of switching case (4), in which band D is tied to band C. Regarding the tied band, a tied band may be set for each of one or more bands among the three or four bands. For example, it is assumed that two bands that support simultaneous transmission are tied to each other, and conversely, it is assumed that two bands that do not support simultaneous transmission are not tied to each other. The tied band may be set, for example, by an RRC parameter (AssociatedBand). Note that a pair of a certain band and a band tied to this band may be referred to as a band pair, etc.

[0109] The above can be summarized as follows: - When twoT is set: When one-port transmission is instructed in a certain band, the terminal 20 switches both of its transmission chains to that band. - When oneT is set: (Scenario 1) When one-port transmission is instructed in a certain band and dual UL between that band and another band is not set, the terminal 20 switches both of its transmission chains to that band, as in the case of twoT. (Scenario 2) When the terminal 20 is in a state of two-port transmission in a certain band (e.g., 2P on band A) and is instructed to transmit one port in another band (e.g., 1P on band B), the terminal 20 switches one of its transmission chains to another band (band B) and leaves the other transmission chain in that band (band A) without switching it (see FIG. 20). (Scenario 3) When terminal 20 is in a state of one-port transmission on one band (e.g., 1P on band A) and one-port transmission on another band (e.g., 1P on band B), and is instructed to transmit one-port on yet another band (e.g., 1P on band C), it switches one transmission chain to yet another band (band C) and switches the other transmission chain to a band (band D) linked to yet another band (see Figure 21).

[0110] In scenarios 1 and 2, the operation of the terminal 20 is clear. On the other hand, in scenario 3, there are cases in which the terminal 20 cannot perform UL transmission in a cell configured in a tied band. In such cases, if the handling of the tied band is not clarified, a misunderstanding may occur between the terminal 20 and the base station 10 regarding the state of the transmission chain during Tx switching (e.g., the linking between the band and the antenna port) and the length of the required switching time, which may result in performance degradation. For example, a secondary cell (Scell) may be activated / deactivated, and if the configured Scell ​​is deactivated, the terminal 20 cannot perform UL transmission in the Scell. Note that "activated" may also be referred to as "active (state)" or "enabled (state)," and "deactivated" may also be referred to as "inactive (state)," "deactivated (state)," "disabled (state)," and the like. As another example, the terminal 20 cannot perform UL transmission in the Scell ​​even when the Scell ​​is released or when the Scell ​​is in a dormancy state. Below, this additional proposal will be described using the example of a case where the Scell ​​is deactivated, but as described above, the case where the terminal 20 cannot perform UL transmission is not limited to a case where the Scell ​​is deactivated.

[0111] A proposal for a simple operation to deal with the case where a cell is deactivated in this way is described in, for example, Non-Patent Document 3.

[0112] A simplified example of switching according to this proposal is shown in Figure 22. As shown in Figure 22, in this example, all cells in band D are deactivated, and band D is deactivated.

[0113] 22 , when the terminal 20 is in a state of one-port transmission in band A and one-port transmission in band B and is instructed to perform one-port transmission in band C, the terminal 20 switches one transmission chain to band C and switches the other transmission chain to band D tied to band C. In other words, the settings related to the tied bands remain valid, and the terminal 20 switches from band A (or band B) to band C and from band B (or band A) to band D, even if the tied band D has been deactivated.

[0114] However, since band D is deactivated, no transmissions will be made on band D, and therefore switching to band D would be a waste.

[0115] Furthermore, following this proposal may result in a longer switching time. For example, if the switching time from band B (or band C) to band D is longer than the switching time from band A (or band B) to band C, the actual switching time will be adjusted to the longer switching time, resulting in a longer switching time. Also, as shown in Figure 22, if one-port transmission on band C is instructed and then two-port transmission on band C is instructed, a switch from band D to band C will occur, resulting in a longer switching time.

[0116] Therefore, although this proposal can avoid misunderstandings between the terminal 20 and the base station 10, there is still a risk of performance degradation due to unnecessary switching.

[0117] In view of the above, in order to prevent or suppress performance degradation due to misunderstandings between a terminal and a base station, the following describes an additional proposal to clarify the operation, etc., when at least one band among bands for which Rel-18 UL Tx switching is set is deactivated.

[0118] In this embodiment, "UL Tx switching schemes across up to 3 or 4 bands with the restriction of up to 2 Tx simultaneous transmission" is assumed, but this is just an example. The maximum number of bands within which transmission switching is performed may be greater than 4. Furthermore, the number of antenna ports used for transmission may be greater than 2. In other words, there may be cases where simultaneous transmission occurs at three or more antenna ports.

[0119] Furthermore, in this embodiment, the expression "simultaneous transmission of band X and band Y is not supported" or similar expressions may be read as "band X and band Y are not configured as dual UL" or "band X is not linked to band Y" or similar expressions.

[0120] <Outline of Additional Proposal> Next, an outline of an additional proposal will be described. According to this additional proposal, in a switching scheme in which two ports can switch between three or more bands as the band used for transmission using two or less bands, if the next transmission after transmission using one of the two ports and a first band (e.g., band A) and the other of the two ports and a second band (e.g., band B) different from the first band is a one-port transmission using a third band (e.g., band C) different from the first band and the second band, and transmission using a fourth band (e.g., band D) linked to the third band is not executable (e.g., the fourth band is deactivated), the terminal 20 may determine, based on a decision rule, to use at least the third band as one of the two or less bands to be used for the next transmission, without using the fourth band that cannot be switched from either the first band or the second band. Furthermore, the terminal 20 may execute the next transmission using at least the third band and one of the two ports, without using the fourth band.

[0121] <Details of Additional Proposals> Next, details of additional proposals will be described. In dual UL, when oneT is configured via uplinkTxSwitching-DualUL-TxState and all serving cells (i.e., band D) in a band (band D) configured as a tied band for a certain band (band C) are deactivated, and switching to another band C (single-port transmission) occurs, the following Alt. 1 to Alt. 3 may be specified. Note that transmission such as single-port transmission or dual-port transmission may be PUSCH transmission, etc.

[0122] Alt. 1: Perform the same operation as when twoT is set via uplinkTxSwitching-DualUL-TxState. Alt. 2: Switch from one of band A and band B to band C, and leave the other of band A and band B as is (retain, do not switch). 2-1: Determine the band to be switched (or the band not to be switched) based on rules specified by the specifications. 2-2: Determine the band to be switched (or the band not to be switched) based on parameters set by the base station. Alt. 3: Determine whether to perform the operation of Alt. 1 or Alt. 2 based on rules specified by the specifications and / or the settings of the base station.

[0123] Alt. 1 to Alt. 3 will be described in detail below.

[0124] (Alt. 1) The terminal 20 may perform the same operation as when twoT is configured via uplinkTxSwitching-DualUL-TxState. That is, the terminal 20 may switch from one band (Band A) to a specified band (Band C) and from the other band (Band B) to the specified band (Band C), and may perform UL transmission using the specified band (Band C) and one port. Alternatively, the terminal 20 may assume that it switches from one band (Band A) to a specified band (Band C) and from the other band (Band B) to the specified band (Band C), and may assume that it performs UL transmission using the specified band (Band C) and one port.

[0125] 23 shows an example of band switching using Alt. 1. As shown in FIG. 23, when one-port transmission in band C is instructed, the terminal 20 may switch from band A to band C and from band B to band C, and perform one-port transmission in band C.

[0126] The base station 10 may assume that the terminal 20 switches from one band (band A) to the specified band (band C) and from the other band (band B) to the specified band (band C), and may assume that the terminal 20 performs UL transmission using the specified band (band C) and one port.

[0127] In the case of Alt. 1, the specification (TS 38.214 Section 6.1.6.2.2) may be changed as shown in FIG. 24 as an example (the underlined parts may be added).

[0128] As shown in FIG. 24 , (in Rel-18 UL Tx switching) after transmission is performed using one of two ports and a first band (Band A) and the other of the two ports and a second band (Band B) different from the first band, if the next transmission is a one-port transmission using a third band (Band C) different from the first band and the second band, and if there is at least one active serving cell in the band (fourth band) linked to the third band (if transmission using the fourth band is executable), the terminal 20 may assume that the next (single-port) transmission will be performed using the third band and the fourth band; otherwise, it may assume that two-port transmission (using the third band) will be performed.

[0129] According to Alt. 1, unnecessary switching to a band not used for transmission (e.g., band D) can be avoided. It may also be possible to omit switching for the next transmission. For example, as shown in FIG. 23 , if one-port transmission on band C is instructed and then two-port transmission on band C is instructed (occurs), band switching is unnecessary (no switching time occurs). Furthermore, since the specification simply specifies the rule that the destination band for both bands is the instructed band, no additional signaling is required.

[0130] In addition, in the above-mentioned scenario 2, if simultaneous transmission using the band (band A) and another band (band B) is not supported and another band (for example, band C) is linked to another band (band B) (referred to as scenario 2'), a problem similar to the above problem may also occur. To solve this problem, the specifications may be modified as shown in FIG. 25. The terminal 20 may assume that the next (single-port) transmission after a transmission using both two ports and the first band (Band A) is a single-port transmission using a second band (Band B) different from the first band (in Rel-18 UL Tx switching), if the band pair of the first band and the second band is not configured as dual UL, at least one band pair (Band B and Band C) with the second band in the band combination is configured as dual UL, and there is at least one active serving cell in the bands (third band, Band C) linked to the second band (when transmission using the third band is executable), or if not, assume that a two-port transmission (using the second band) is executed. Alternatively, in Scenario 2′, modifications identical to or similar to those described in FIG. 28 (related to Alt. 2-1) described later may be applied.

[0131] (Alt. 2) The terminal 20 may switch from one of two bands (Band A and Band B) to a specified band (Band C) and leave the other of the two bands (Band A and Band B) as is, or may perform UL transmission using the specified band (Band C) and one port. In this case, because there are multiple candidate bands to switch to, it is necessary to identify or determine a band that is not to be switched to, i.e., a band that is to be left as is or retained (or a band to be switched to). Therefore, the terminal 20 may identify or determine a band that is not to be switched to (or a band to be switched to) based on 2-1 and 2-2 below, and then switch from one of Band A and Band B that is to be switched to Band C, and leave the other of Band A and Band B that is not to be switched to as is.

[0132] [2-1] The terminal 20 may identify or determine a band that is not subject to switching (or a band that is subject to switching) based on a rule defined by the specifications. Such a rule may be referred to as a specific rule or a determination rule. When the specific rule or the determination rule is a rule defined by the specifications, it may be interpreted as a predefined rule. The specific rule or the determination rule may be, for example, the rules shown in 2-1-1 to 2-1-3 below.

[0133] 2-1-1: Leave the band with the smaller (or larger) band index as it is

[0134] 2-1-2: Leave the band with the higher (or lower) band priority as is. Note that the band priority may be set to determine the band for which a switching time is set (i.e., the transmission time is shortened).

[0135] 2-1-3: Leave the band with the shorter (or longer) switching time as is. Leaving the band with the shorter switching time as is allows for more efficient transmission, while leaving the band with the longer switching time as is allows for safer transmission.

[0136] The band index, band priority, switching time, etc. may also be referred to as configuration information (or parameters or information) for determining the band to be switched, configuration information (or parameters or information) regarding the decision rule, configuration information (or parameters or information) regarding UL transmission switching, etc.

[0137] The terminal 20 may keep the band (Band A) having the larger (or smaller) parameter value as it is, switch from the band (Band B) having the smaller (or larger) parameter value to the designated band (Band C), and perform UL transmission using the designated band (Band C) and one port. Alternatively, the terminal 20 may keep the band (Band A) having the larger (or smaller) parameter value as it is, switch from the band (Band B) having the smaller (or larger) parameter value to the designated band (Band C), and perform UL transmission using the designated band (Band C) and one port.

[0138] 26 shows an example of band switching by 2-1 of Alt. 2. As shown in FIG. 26, when terminal 20 is instructed to perform single-port transmission in band C, it may switch from band B to band C while leaving band A as is, and perform single-port transmission in band C, in accordance with the rules shown in 2-1-1 to 2-1-3 above.

[0139] The base station 10 may assume that the terminal 20 will leave the band (band A) having the larger (or smaller) parameter value as is and switch from the band (band B) having the smaller (or larger) parameter value to the indicated band (band C), and may assume that the terminal 20 will perform UL transmission using the indicated band (band C) and one port.

[0140] In the case of Alt. 2-1, the specification (TS 38.214 Section 6.1.6.2.2) may be changed as shown in FIG. 27 (the underlined parts may be added), for example.

[0141] As shown in FIG. 27 , the terminal 20 may assume that (in Rel-18 UL Tx switching) after a transmission is performed using one of the two ports (band A) and the first band and the other of the two ports and a second band (band B) different from the first band, the next transmission is a one-port transmission using a third band (band C) different from the first band and the second band, and if there is at least one active serving cell in the band (fourth band) linked to the third band (if transmission using the fourth band is executable), the next (one-port) transmission will be performed using the third band and the fourth band. The terminal 20 may assume that (in Rel-18 UL Tx switching) after transmission using one of the two ports (Band A) and the first band and the other of the two ports and a second band (Band B) different from the first band, the next transmission is a single-port transmission using a third band (Band C) different from the first and second bands, and if there is an active serving cell in the band (Fourth band) linked to the Third band (when transmission using the Fourth band is not possible), the next (single-port) transmission will be performed using the Third band and either the First band or the Second band having the larger (or smaller) parameter value. In other cases, the terminal 20 may assume that two-port transmission (using the Third band) will be performed.

[0142] [Variation of 2-1] Alternatively or additionally, the terminal 20 may determine which bands to switch to or not switch to, taking into account whether simultaneous transmission with band C is supported. For example, if simultaneous transmission between bands A and C and between bands B and C are not supported, the terminal 20 may switch from band A to band C and from band B to band C, as in Alt. 1.

[0143] According to Alt. 2-2-1, unnecessary switching to a band not used for transmission (e.g., band D) can be avoided. Furthermore, since only one transmission chain needs to be switched, it may be possible to shorten the switching time and omit switching for the next transmission. For example, as shown in FIG. 26, if one-port transmission on band C is instructed, and then one-port transmission on band A and one-port transmission on band C are instructed (occur), band switching is unnecessary (no switching time occurs). Furthermore, since bands not to be switched (and therefore bands to be switched) are specified by the specifications, additional signaling is unnecessary.

[0144] In addition, in the above-described scenario 2′, the specifications may be modified as shown in FIG. 28 . In the following cases, after a transmission using both two ports and the first band (Band A) is performed (in Rel-18 UL Tx switching), the next transmission is a single-port transmission using a second band (Band B) different from the first band; the band pair of the first band and the second band is not configured as dual UL; at least one band pair (Band B and Band C) with the second band in the band combination is configured as dual UL; and there is at least one active serving cell in the bands (third band, Band C) linked to the second band (when transmission using the third band is executable), the terminal 20 may assume that the next (single-port) transmission is performed using the second band and the third band; otherwise, the terminal 20 may assume that a two-port transmission (using the second band) is performed. Alternatively, in scenario 2′, modifications identical to or similar to the modification of the specifications described in the above-described FIG. 25 (related to Alt.) may be applied.

[0145] [2-2] The terminal 20 may identify a band that is not subject to switching (or a band that is subject to switching) based on parameters set by the base station 10. For example, the base station 10 may set parameters indicating which rule to apply among the rules shown in 2-1-1 to 2-1-3 above (e.g., information identifying the rule (ID, index, etc.)) (and, for example, a parameter indicating whether to keep the band with the smaller band index or the band with the larger band index), and transmit the set parameters to the terminal 20. The terminal 20 may identify the rule to apply and the band that is not subject to switching (or a band that is subject to switching) based on the parameters set by the base station 10, switch from one of the two bands (Band A and Band B) to the designated band (Band C), and leave the other of the two bands (Band A and Band B) as is. The parameters set by the base station 10 may be referred to as setting information (or parameters or information) related to the decision rule, setting information (or parameters or information) related to UL transmission switching, etc.

[0146] According to Alt. 2-2, unnecessary switching to a band not used for transmission (e.g., band D) can be avoided. Furthermore, since only one transmission chain needs to be switched, it may be possible to shorten the switching time and omit switching for the next transmission. For example, similar to Alt. 2-1, if one-port transmission on band C is instructed, and then one-port transmission on band A and one-port transmission on band C are instructed (occur), band switching is unnecessary (no switching time occurs). Furthermore, the base station can flexibly set the rules to be applied.

[0147] (Alt. 3) The terminal 20 may determine whether to perform the operation of Alt. 1 or the operation of Alt. 2 based on rules defined by specifications and / or settings of the base station 10.

[0148] For example, a rule may be defined in the specifications such that the operation of Alt. 1 (or Alt. 2) is performed in the case of scenario 3, and the operation of Alt. 2 (or Alt. 1) is performed in the case of scenario 2′, and the operation when the tying band is deactivated may be different between the case of scenario 3 and the case of scenario 2′.

[0149] Furthermore, for example, the base station 10 may change the operation when the tying band is deactivated by setting a parameter indicating that the operation of Alt. 1 is to be performed in some cases and a parameter indicating that the operation of Alt. 2 is to be performed in other cases.

[0150] <Operation Example> Next, an operation example of the terminal 20 will be described with reference to FIG.

[0151] In step S11, in a switching method in which two ports can switch between three or more bands as the bands used for transmission using two or less bands, if the next transmission after transmission using one of the two ports and the first band and the other of the two ports and a second band different from the first band is a one-port transmission using a third band different from the first band and the second band, and transmission using a fourth band linked to the third band is not possible, the terminal 20 decides, based on a decision rule, to use at least the third band as one of the two or less bands to be used for the next transmission, rather than the fourth band which cannot be switched from either the first band or the second band.

[0152] In step S12, the terminal 20 performs the next transmission using at least the third band and one of the two ports, without using the fourth band.

[0153] Next, the configurations of the base station 10 and the terminal 20 will be described. Note that the configurations of the base station 10 and the terminal 20 described below are examples of functions related to this embodiment. The base station 10 and the terminal 20 may have functions not shown. Furthermore, the names of the functional divisions and / or functional units are not limited as long as they are functions that perform operations related to this embodiment.

[0154] <Configuration of Base Station> Fig. 30 is a block diagram showing an example of the configuration of base station 10 according to this embodiment. Base station 10 includes, for example, a transmitting unit 101, a receiving unit 102, and a control unit 103. Base station 10 communicates with terminal 20 (see Fig. 31) wirelessly.

[0155] The transmitter 101 transmits a downlink (DL) signal to the terminal 20. For example, the transmitter 101 transmits the DL signal under the control of the controller 103.

[0156] The DL signal may include, for example, a downlink data signal and control information (e.g., Downlink Control Information (DCI)). The DL signal may also include information indicating scheduling related to signal transmission of the terminal 20 (e.g., an UL grant). The DL signal may also include control information of higher layers (e.g., control information of Radio Resource Control (RRC)). The DL signal may also include a reference signal.

[0157] The channels used for transmitting DL signals include, for example, a downlink data channel and a downlink control channel. For example, the downlink data channel may include a PDSCH (Physical Downlink Shared Channel), and the downlink control channel may include a PDCCH (Physical Downlink Control Channel). For example, the base station 10 transmits downlink control information to the terminal 20 using the PDCCH and transmits downlink data signals using the PDSCH.

[0158] The reference signal included in the DL signal may include at least one of a demodulation reference signal (Demodulation Reference Signal (DMRS)), a Phase Tracking Reference Signal (PTRS), a Channel State Information-Reference Signal (CSI-RS), a Sounding Reference Signal (SRS), and a Positioning Reference Signal (PRS) for position information. For example, reference signals such as DMRS and PTRS are used for demodulating downlink data signals and are transmitted using the PDSCH.

[0159] The receiving unit 102 receives an uplink (UL) signal transmitted from the terminal 20. For example, the receiving unit 102 receives the UL signal under the control of the control unit 103.

[0160] The transmitting unit 101 and the receiving unit 102 may be collectively referred to as a communication unit.

[0161] The control unit 103 controls the communication operations of the base station 10 , including the transmission processing of the transmission unit 101 and the reception processing of the reception unit 102 .

[0162] For example, the control unit 103 acquires information such as data and control information from the upper layer and outputs it to the transmitting unit 101. The control unit 103 also outputs the data, control information, etc. received from the receiving unit 102 to the upper layer.

[0163] For example, the control unit 103 allocates resources (or channels) used for transmitting and receiving DL signals and / or resources used for transmitting and receiving UL signals based on signals (e.g., data and control information, etc.) received from the terminal 20 and / or data and control information, etc. acquired from a higher layer. Information about the allocated resources may be included in control information transmitted to the terminal 20. For example, the control unit 103 may be assumed as described in this proposal.

[0164] 31 is a block diagram showing an example of the configuration of terminal 20 according to this embodiment. Terminal 20 includes, for example, a receiving unit 201, a transmitting unit 202, and a control unit 203. Terminal 20 communicates with base station 10, for example, wirelessly.

[0165] The receiving unit 201 receives a DL signal transmitted from the base station 10. For example, the receiving unit 201 receives the DL signal under the control of the control unit 203.

[0166] For example, the receiving unit 201 may receive from the base station 10 setting information regarding the decision rule, setting information regarding UL transmission switching, setting information for determining the band to be switched, and an instruction for transmission (such as one-port transmission).

[0167] The transmitting unit 202 transmits the UL signal to the base station 10. For example, the transmitting unit 202 transmits the UL signal under the control of the control unit 203.

[0168] For example, the transmitter 202 may perform the next transmission using at least the third band and one of the two ports, without using the fourth band.

[0169] The UL signal may include, for example, an uplink data signal and control information (e.g., UCI). For example, information related to the processing capability of the terminal 20 (e.g., UE capability) may be included. The UL signal may also include a reference signal.

[0170] Channels used for transmitting UL signals include, for example, an uplink data channel and an uplink control channel. For example, the uplink data channel includes a PUSCH (Physical Uplink Shared Channel), and the uplink control channel includes a PUCCH (Physical Uplink Control Channel). For example, the terminal 20 transmits uplink control information to the base station 10 using the PUCCH and transmits uplink data signals using the PUSCH.

[0171] The reference signals included in the UL signal may include, for example, at least one of DMRS, PTRS, CSI-RS, SRS, and PRS. For example, the reference signals such as DMRS and PTRS are used for demodulating the uplink data signal and are transmitted using an uplink channel (for example, PUSCH).

[0172] The receiving unit 201 and the transmitting unit 202 may be collectively referred to as a communication unit.

[0173] The control unit 203 controls the communication operations of the terminal 20 , including the reception processing in the receiving unit 201 and the transmission processing in the transmitting unit 202 .

[0174] For example, the control unit 203 acquires information such as data and control information from the upper layer and outputs it to the transmitting unit 202. Also, the control unit 203 outputs, for example, the data and control information received from the receiving unit 201 to the upper layer.

[0175] For example, the control unit 203 controls transmission of information to be fed back to the base station 10. The information to be fed back to the base station 10 may include, for example, HARQ-ACK, Channel State Information (CSI), or a Scheduling Request (SR). The information to be fed back to the base station 10 may be included in UCI.

[0176] For example, the receiver 201 may receive from the base station 10 configuration information regarding switching in a switching scheme in which two ports can be switched between a maximum of three or more bands to be used for transmission. When only two bands are set as bands to be used in the configuration information, the controller 203 may determine to perform transmission switching between transmission using one of the two bands using only one of the two ports and transmission using the other of the two bands using only the other of the two ports, or to not perform the transmission switching. Furthermore, for example, the controller 203 may determine not to perform transmission switching by not assuming that transmission switching will be set in the configuration information. Furthermore, for example, the transmitter 202 may transmit to the base station 10 information indicating that the terminal 20 supports transmission switching set in the configuration information. When transmission switching is set in the configuration information, the controller 203 may determine to perform transmission switching. Furthermore, for example, the information may indicate that the terminal 20 supports uplink MIMO (Multi-Input Multi-Output) using two ports. Also, for example, the control unit 203 may decide to switch transmission in accordance with a value different from the value that can be set in the setting information.

[0177] For example, in a switching scheme in which two ports can switch between three or more bands as the bands used in a transmission using two or less bands, if a next transmission after a transmission using one of the two ports and a first band and the other of the two ports and a second band different from the first band is a one-port transmission using a third band different from the first band and the second band, and a transmission using a fourth band linked to the third band is not executable, the control unit 203 may determine, based on a determination rule, to use at least the third band as one of the two or less bands to be used in the next transmission, without using the fourth band that cannot be switched from either the first band or the second band. For example, the control unit 203 may determine to use the third band that can be switched from both the first band and the second band as one of the two or less bands to be used in the next transmission. For example, the control unit 203 may determine to use the third band that can be switched from one of the first band and the second band, and the other of the first band and the second band that cannot be switched, as the two or less bands to be used in the next transmission. For example, the control unit 203 may determine the third band and the other of the first band and the second band as the two or fewer bands to be used for the next transmission based on a predefined decision rule or based on received setting information regarding the decision rule.

[0178] Note that the channel used for transmitting the DL signal and the channel used for transmitting the UL signal are not limited to the above-mentioned example. For example, the channel used for transmitting the DL signal and the channel used for transmitting the UL signal may include a Random Access Channel (RACH) and a Physical Broadcast Channel (PBCH). The RACH may be used to transmit Downlink Control Information (DCI) including a Random Access Radio Network Temporary Identifier (RA-RNTI), for example.

[0179] The above configuration can reduce the impact of scheduling restrictions on measurements.

[0180] <Summary of embodiment> As described above, according to one aspect of the present disclosure, there is provided a terminal including: a receiver that receives, from a base station, setting information related to switching in a switching method in which two ports can be switched between a maximum of three or more settable bands used for transmission; and a controller that, when only two bands are set as the bands to be used in the setting information, performs transmission switching that switches between transmission using one of the two bands at only one of the two ports and transmission using the other of the two bands at only the other of the two ports, or determines not to perform the transmission switching.

[0181] In one example, the control unit determines not to perform the transmission switching by not assuming that the transmission switching will be set in the setting information.

[0182] In one example, the terminal further includes a transmitting unit that transmits information to the base station indicating that the terminal is capable of setting the transmission switching in the setting information, and the control unit decides to perform the transmission switching if the transmission switching is set in the setting information.

[0183] In one example, the information indicates that the terminal supports uplink multi-input multi-output (MIMO) using the two ports.

[0184] In one example, the control unit determines to perform the transmission switching according to a value different from a value that can be set in the setting information.

[0185] According to one aspect of the present disclosure, a communication method is provided in which a terminal receives configuration information from a base station regarding switching in a switching method in which two ports can be switched between a maximum of three or more bands that can be set as bands to be used for transmission, and when only two bands are set as bands to be used in the configuration information, the terminal performs transmission switching to switch between transmission using one of the two bands using only one of the two ports and transmission using the other of the two bands using only the other of the two ports, or determines not to perform the transmission switching.

[0186] The above configuration clarifies how to perform UL Tx switching between two bands, so that UL transmission switching can be performed appropriately.

[0187] Furthermore, as described above, according to one aspect of the present disclosure, in a switching method in which two ports can switch between three or more bands as the bands used for transmission in which two or less bands are used, if a next transmission after a transmission using one of the two ports and a first band and the other of the two ports and a second band different from the first band is a one-port transmission using a third band different from the first band and the second band, and a transmission using a fourth band linked to the third band is not executable, a terminal is provided that includes: a control unit that determines, based on a decision rule, to use at least the third band as one of the two or less bands to be used for the next transmission, without using the fourth band that cannot be switched from either the first band or the second band; and a transmitting unit that performs the next transmission without using the fourth band, but using at least the third band and one of the two ports.

[0188] With the above configuration, two or less bands to be used for the next transmission can be determined based on the decision rule, so that UL transmission switching can be performed appropriately while preventing or suppressing performance degradation during UL transmission switching.

[0189] In one example, the control unit determines to use the third band, which can be switched from both the first band and the second band, as one of the two or less bands to be used for the next transmission.

[0190] With the above configuration, no additional signaling is required.

[0191] In one example, the control unit determines that the two or fewer bands to be used for the next transmission will be the third band, which can be switched from one of the first band and the second band, and the other of the first band and the second band, which cannot be switched.

[0192] The above configuration may enable the switching time to be shortened, the switching for the next transmission to be omitted, etc.

[0193] In one example, the decision rule is a predefined rule.

[0194] With the above configuration, no additional signaling is required.

[0195] In one example, the terminal further includes a receiving unit that receives configuration information regarding the decision rule from a base station, and the control unit determines, based on the configuration information, the third band and the other of the first band and the second band as the two or fewer bands to be used for the next transmission.

[0196] The above configuration allows flexible setting of decision rules, etc.

[0197] According to one aspect of the present disclosure, in a switching method in which a terminal can switch two ports between three or more bands as the band to be used for transmission using two or less bands, if a next transmission after a transmission using one of the two ports and a first band and the other of the two ports and a second band different from the first band is a one-port transmission using a third band different from the first band and the second band, and a transmission using a fourth band linked to the third band is not executable, a communication method is provided in which, based on a decision rule, it is decided to use at least the third band as one of the two or less bands to be used for the next transmission, rather than the fourth band that cannot be switched from either the first band or the second band, and the next transmission is executed without using the fourth band, but using at least the third band and one of the two ports.

[0198] With the above configuration, two or less bands to be used for the next transmission can be determined based on the decision rule, so that UL transmission switching can be performed appropriately while preventing or suppressing performance degradation during UL transmission switching.

[0199] <Hardware Configuration, etc.> The block diagrams used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may also be realized by combining software with the single device or the multiple devices.

[0200] Functions include, but are not limited to, judgment, determination, assessment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how these functions are implemented.

[0201] For example, a base station, a terminal, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the communication method of the present disclosure. Fig. 32 is a diagram illustrating an example of the hardware configuration of a base station and a terminal according to an embodiment of the present disclosure. The above-described base station 10 and terminal 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0202] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the base station 10 and the terminal 20 may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0203] Each function in the base station 10 and the terminal 20 is realized by loading specified software (programs) onto hardware such as the processor 1001 and the memory 1002, causing the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of reading and writing data in the memory 1002 and the storage 1003.

[0204] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured by a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control unit 103 and control unit 203 may be realized by the processor 1001.

[0205] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 203 of the terminal 20 may be implemented by a control program stored in the memory 1002 and running on the processor 1001, and similar implementations may be made for other functional blocks. While the above-described various processes have been described as being executed by one processor 1001, they may also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may also be transmitted from a network via a telecommunications line.

[0206] The memory 1002 is a computer-readable recording medium and may be configured by, for example, at least one of a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 can store executable programs (program codes), software modules, etc. for implementing a communication method according to an embodiment of the present disclosure.

[0207] Storage 1003 is a computer-readable recording medium, and may be composed of at least one of, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned storage medium may be, for example, a database, a server, or other appropriate medium including at least one of memory 1002 and storage 1003.

[0208] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the above-mentioned transmitter 101, receiver 102, receiver 201, transmitter 202, etc. may be realized by the communication device 1004.

[0209] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0210] Furthermore, each device, such as the processor 1001 and the memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0211] Furthermore, the base station 10 and the terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0212] (Supplementary Notes on the Embodiments) Although the embodiments of the present disclosure have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present disclosure; matters described in two or more items may be used in combination as needed, and matters described in one item may apply to matters described in another item (unless inconsistent). Boundaries between functional units or processing units in functional block diagrams do not necessarily correspond to boundaries between physical components. The operations of multiple functional units may be performed by a single physical component, or the operations of a single functional unit may be performed by multiple physical components. The order of processing procedures described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, base stations and terminals have been described using functional block diagrams, but such devices may be implemented in hardware, software, or a combination thereof. The software operated by the processor of a base station in accordance with an embodiment of the present disclosure, and the software operated by the processor of a terminal in accordance with an embodiment of the present disclosure may each be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or any other suitable storage medium.

[0213] <Notification of Information, Signaling> Notification of information is not limited to the embodiments described in the present disclosure and may be performed using other methods. For example, notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI) and Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB) and System Information Block (SIB))), other signals, or a combination thereof. Furthermore, RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0214] <Applicable Systems> The embodiments described in the present disclosure are applicable to LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (x is, for example, an integer or a decimal)), FRA (Future Radio Access), NR (new Radio), New radio access (NX), Future generation radio access (FX), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.17 (WiMAX (registered trademark)), IEEE 802.19 (WiMAX (registered trademark)), IEEE 802.20 (WiMAX (registered trademark)), IEEE 802.21 (Wi-Fi (registered trademark)), IEEE 802.22 (WiMAX (registered trademark)), IEEE 802.23 (WiMAX (registered trademark)), IEEE 802.24 (WiMAX (registered trademark)), IEEE 802.25 (WiMAX (registered trademark)), IEEE 802.26 (WiMAX (registered trademark)), IEEE 802.27 (WiMAX (registered trademark)), IEEE 802.28 (WiMAX (registered trademark)), IEEE 802.29 (WiMAX (registered trademark)), IEEE 802.30 (WiMAX (registered trademark)), IEEE 802.31 (Wi-Fi (registered trademark)), IEEE 802.32 (WiMAX (registered trademark)), IEEE 802.33 (WiMAX (registered trademark)), IEEE 802.34 (WiMAX (registered trademark The present invention may be applied to at least one of systems using 802.20, UWB (Ultra-Wide Band), Bluetooth (registered trademark), or other suitable systems, and next-generation systems that are extended, modified, created, or defined based on these systems. The present invention may also be applied to a combination of multiple systems (e.g., a combination of LTE and / or LTE-A with 5G).

[0215] <Processing Procedures, etc.> The processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be rearranged unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0216] <Operation of Base Station> In the present disclosure, specific operations described as being performed by a base station may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal may be performed by at least one of the base station and another network node other than the base station (for example, an MME or an S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, a combination of multiple other network nodes (for example, an MME and an S-GW) may also be used.

[0217] <Direction of Input / Output> Information, etc. (see <Information, Signal>) can be output from a higher layer (or a lower layer) to a lower layer (or a higher layer). It may also be input / output via multiple network nodes.

[0218] <Handling of Input / Output Information, etc.> Input / output information, etc. may be stored in a specific location (for example, memory) or may be managed using a management table. Input / output information, etc. may be overwritten, updated, or added. Output information, etc. may be deleted. Input information, etc. may be sent to another device.

[0219] <Determination method> The determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0220] <Variations of Aspects, etc.> Each aspect / embodiment described in the present disclosure may be used alone, in combination, or switched depending on the implementation. In addition, notification of predetermined information (e.g., notification that "X is true") is not limited to being done explicitly, but may be done implicitly (e.g., by not notifying the predetermined information).

[0221] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0222] <Software> Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0223] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0224] Information, Signals, etc., described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc., which may be referred to throughout the above description, may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0225] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0226] <System, Network> As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0227] <Parameter and Channel Names> Furthermore, the information, parameters, and the like described in the present disclosure may be expressed using absolute values, relative values ​​from a predetermined value, or other corresponding information. For example, a radio resource may be indicated by an index.

[0228] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0229] <Base Station> In the present disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. A base station may also be referred to by terms such as a macrocell, a small cell, a femtocell, and a picocell.

[0230] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be partitioned into multiple smaller areas, and each smaller area can also be provided with communication services by a base station subsystem (e.g., a remote radio head (RRH)). The terms "cell" or "sector" refer to part or the entire coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0231] In the present disclosure, the base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control or operate based on the information.

[0232] Mobile Station In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," and the like may be used interchangeably.

[0233] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0234] <Base Station / Mobile Station> At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, etc. The mobile object refers to a movable object, and may move at any speed. Naturally, this also includes cases where the mobile object is stationary. Examples of the mobile object include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcars, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and objects mounted thereon. The mobile object may also be a mobile object that moves autonomously based on an operational command. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may be a device that does not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0235] Furthermore, a base station in the present disclosure may be read as a terminal. For example, the embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a terminal is replaced with communication between multiple terminals (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). In this case, the terminal may be configured to have the functions of the base station described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to communication between terminals (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0236] Similarly, the term "terminal" in the present disclosure may be read as "base station." In this case, the base station may be configured to have the functions of the terminal described above.

[0237] Fig. 33 shows a configuration example of a vehicle 2001. As shown in Fig. 33, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. Each aspect / embodiment described in the present disclosure may be applied to a communication device mounted on the vehicle 2001, and may be applied to the communication module 2013, for example.

[0238] The drive unit 2002 is configured, for example, by an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user.

[0239] The electronic control unit 2010 is composed of a microprocessor 2031, a memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals are input to the electronic control unit 2010 from various sensors 2021 to 2029 provided in the vehicle 2001. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0240] The signals from the various sensors 2021 to 2029 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0241] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing (outputting) various types of information, such as driving information, traffic information, and entertainment information, and one or more ECUs that control these devices. The information service unit 2012 provides various types of multimedia information and multimedia services to the occupants of the vehicle 2001 by using information acquired from external devices via the communication module 2013, etc.

[0242] The information service unit 2012 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

[0243] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driving burden on the driver, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS, etc.), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. In addition, the driving assistance system unit 2030 transmits and receives various information via the communication module 2013 to realize the driving assistance function or the autonomous driving function.

[0244] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 2029, which are provided in the vehicle 2001.

[0245] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

[0246] The communication module 2013 may transmit at least one of signals from the above-mentioned various sensors 2021 to 2029 input to the electronic control unit 2010, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 2012 to an external device via wireless communication. The electronic control unit 2010, the various sensors 2021 to 2029, the information service unit 2012, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above-mentioned input.

[0247] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on an information service unit 2012 provided in the vehicle 2001. The information service unit 2012 may be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores the various information received from external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021 to 2029, and the like provided in the vehicle 2001.

[0248] <Meaning and Interpretation of Terms> As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching a table, database, or other data structure), ascertaining something that is considered to be a "judging" or "determining," and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like that are considered to be a "judging" or "determining." Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0249] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0250] <Reference Signal> A reference signal can also be abbreviated as RS (Reference Signal), and may also be called a pilot depending on the applicable standard.

[0251] <Meaning of "based on"> As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0252] "First," "Second" Any reference to an element using designations such as "first," "second," etc., used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must precede the second element in some way.

[0253] <Means> The "means" in the configuration of each device above may be replaced with "section," "circuit," "device," etc.

[0254] Open Format: When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0255] <Time Units such as TTI, Frequency Units such as RB, and Radio Frame Configuration> A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0256] Numerology may be a communication parameter that applies to the transmission and / or reception of a signal or channel, and may indicate, for example, at least one of subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0257] A slot may be composed of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol). A slot may be a time unit based on numerology.

[0258] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0259] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0260] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc. instead of a subframe.

[0261] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) to each user terminal in TTI units. Note that the definition of TTI is not limited to this.

[0262] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0263] When one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0264] A TTI having a time length of 1 ms may be called a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0265] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and greater than or equal to 1 ms.

[0266] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may be determined based on numerology.

[0267] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0268] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0269] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0270] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a Common Reference Point of the carrier. PRBs may be defined in a BWP and numbered within the BWP.

[0271] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0272] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0273] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples, and various changes may be made to the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc.

[0274] <Maximum Transmit Power> The "maximum transmit power" in the present disclosure may refer to the maximum value of transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0275] Articles In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0276] <"Different"> In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." Note that the term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0277] This patent application claims priority based on Japanese Patent Application No. 2024-031284, filed on March 1, 2024, the entire contents of which are incorporated herein by reference.

[0278] One aspect of the present disclosure is useful in wireless communication systems.

[0279] 10 Base station 20 Terminal 101, 202 Transmitter 102, 201 Receiver 103, 203 Controller

Claims

1. A terminal comprising: a receiver that receives from a base station configuration information regarding switching in a switching method in which two ports can be switched between a maximum of three or more bands that can be set as bands to be used for transmission; and a controller that, when only two bands are set as bands to be used in the configuration information, performs transmission switching between transmission using one of the two bands using only one of the two ports and transmission using the other of the two bands using only the other of the two ports, or determines not to perform the transmission switching.

2. The terminal according to claim 1, wherein the control unit determines not to perform the transmission switching by not assuming that the transmission switching will be set in the setting information.

3. The terminal according to claim 1, further comprising a transmitting unit that transmits to the base station information indicating that the terminal is compatible with the transmission switching being set in the setting information, wherein the control unit decides to perform the transmission switching when the transmission switching is set in the setting information.

4. The terminal according to claim 3, wherein the information indicates that the terminal supports uplink MIMO (Multi-Input Multi-Output) using the two ports.

5. The terminal according to claim 1, wherein the control unit determines to perform the transmission switching in accordance with a value different from a value that can be set in the setting information.

6. A communications method in which a terminal receives from a base station configuration information regarding switching in a switching method in which two ports can switch between a maximum of three or more bands that can be set as bands to be used for transmission, and when only two bands are set as bands to be used in the configuration information, the terminal performs transmission switching between transmitting using one of the two bands using only one of the two ports and transmitting using the other of the two bands using only the other of the two ports, or decides not to perform the transmission switching.

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