Terminal and communication method

Abstract

To reduce synchronization processing related to QCL (Quasi-Co-Location) in a wireless communication system.SOLUTION: A terminal includes a receiving unit that receives first DCI (Downlink Control Information) and second DCI, and a control unit that applies a TCI (Transmission Configuration Indicator) state notified by the first DCI to reception of a data channel scheduled by the second DCI.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a terminal and a communication method in a wireless communication system. [Background technology]

[0002] For NR (New Radio) (also known as "5G"), the successor system to LTE (Long Term Evolution), technologies that satisfy requirements such as 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 are being considered (for example, Non-Patent Document 1).

[0003] NR uses higher frequency bands than LTE. Because propagation loss increases in higher frequency bands, studies are being conducted to improve received power by applying narrow beamforming to radio signals to compensate for this propagation loss (e.g., Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.300 V15.6.0(2019-06) [Non-patent document 2] 3GPP TS 38.211 V15.6.0(2019-06) Summary of the Invention [Problem to be solved by the invention]

[0005] In an NR wireless communication system, when a base station switches a transmission beam, the terminal needs to switch Quasi-co-location (QCL) information associated with a synchronization signal or a reference signal. When switching QCL information, the terminal needs to perform, for example, synchronization processing or learning of a transmit / receive beam pair.

[0006] The present invention has been made in view of the above points, and has an object to reduce synchronization processing related to QCL (Quasi-co-location) in a wireless communication system. [Means for solving the problem]

[0007] According to the disclosed technology, a mobile station includes a receiver that receives first DCI (Downlink Control Information) and second DCI, and a controller that applies a TCI (Transmission configuration indicator) state notified by the first DCI to reception of a data channel scheduled by the second DCI. and when the second DCI is received after a certain period has elapsed since the first DCI was received, the control unit applies the TCI state to the reception of the second DCI. A terminal is provided. [Effects of the Invention]

[0008] According to the disclosed technology, it is possible to reduce synchronization processing related to Quasi-co-location (QCL) in a wireless communication system. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a wireless communication system. [Figure 2] FIG. 10 is a sequence diagram illustrating an example in which a TCI state is set. [Figure 3] FIG. 10 is a diagram for explaining an example of beam management. [Figure 4] FIG. 1 is a diagram illustrating an example of a QCL. [Figure 5] FIG. 10 is a diagram showing an example (1) of switching QCL information in an embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing an example (2) of switching QCL information in the embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing an example (1) of a notification by DCI in an embodiment of the present invention. [Figure 8]FIG. 10 is a diagram showing an example (2) of a notification by DCI in the embodiment of the present invention. [Figure 9] FIG. 2 is a diagram illustrating an example (1) of setting a PDCCH according to an embodiment of the present invention. [Figure 10] FIG. 10 is a diagram illustrating an example (2) of configuring a PDCCH according to an embodiment of the present invention. [Figure 11] 2 is a diagram illustrating an example of a functional configuration of a base station 10 according to an embodiment of the present invention. [Figure 12] FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal 20 according to the embodiment of the present invention. [Figure 13] 2 is a diagram illustrating an example of a hardware configuration of a base station 10 or a terminal 20 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0011] In the operation of the wireless communication system according to the embodiment of the present invention, existing technologies are used as appropriate. However, the existing technologies are, for example, but not limited to, the existing LTE. Furthermore, the term "LTE" used in this specification has a broad meaning including LTE-Advanced and systems subsequent to LTE-Advanced (e.g., NR) unless otherwise specified.

[0012] Furthermore, in the embodiments of the present invention described below, terms used in existing LTE, such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel), are used. This is for convenience of description, and similar signals, functions, etc. may be referred to by other names. Furthermore, the above-mentioned terms in NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, NR-PDCCH, NR-PDSCH, NR-PUCCH, NR-PUSCH, etc. However, even signals used in NR are not necessarily designated as "NR-."

[0013] Furthermore, in the embodiments of the present invention, the duplex method may be a TDD (Time Division Duplex) method, an FDD (Frequency Division Duplex) method, or other methods (for example, Flexible Duplex, etc.).

[0014] In the following description, the method of transmitting a signal using a transmit beam may be digital beamforming, which transmits a signal multiplied by a precoding vector (precoded with the precoding vector), or analog beamforming, which realizes beamforming using a variable phase shifter in an RF (Radio Frequency) circuit. Similarly, the method of receiving a signal using a receive beam may be digital beamforming, which multiplies a received signal by a predetermined weight vector, or analog beamforming, which realizes beamforming using a variable phase shifter in an RF circuit. Hybrid beamforming, which combines digital beamforming and analog beamforming, may also be applied. Furthermore, transmitting a signal using a transmit beam may mean transmitting the signal from a specific antenna port. Similarly, receiving a signal using a receive beam may mean receiving the signal from a specific antenna port. An antenna port refers to a logical antenna port or a physical antenna port defined in the 3GPP (registered trademark) standard.

[0015] The method of forming the transmission beam and the reception beam is not limited to the above method. For example, in a base station 10 or a terminal 20 equipped with multiple antennas, a method of changing the angle of each antenna may be used, a method of combining a method of using a precoding vector and a method of changing the antenna angle may be used, a method of switching between different antenna panels may be used, a method of combining a method of using multiple antenna panels together may be used, or other methods may be used. Also, for example, in a high frequency band, multiple different transmission beams may be used. The use of multiple transmission beams is called multi-beam operation, and the use of one transmission beam is called single-beam operation.

[0016] Furthermore, in the embodiments of the present invention, when radio parameters and the like are "configured," it may mean that predetermined values ​​are pre-configured, or that radio parameters notified from the base station 10 or the terminal 20 are set.

[0017] Fig. 1 is a diagram showing an example of the configuration of a wireless communication system. As shown in Fig. 1, the wireless communication system according to the embodiment of the present invention includes a base station 10 and a terminal 20. Although Fig. 1 shows one base station 10 and one terminal 20, this is an example, and there may be a plurality of each.

[0018] The base station 10 is a communication device that provides one or more cells and performs wireless communication with the terminal 20. The physical resources of a wireless signal are defined in the time domain and the frequency domain. The time domain may be defined by the number of OFDM symbols, and the frequency domain may be defined by the number of subcarriers or the number of resource blocks. The base station 10 transmits a synchronization signal and system information to the terminal 20. The synchronization signal is, for example, NR-PSS and NR-SSS. Part of the system information is transmitted, for example, via the NR-PBCH and is also referred to as broadcast information. The synchronization signal and broadcast information may be periodically transmitted as an SSB (SS / PBCH block) consisting of a predetermined number of OFDM symbols. For example, the base station 10 transmits a control signal or data to the terminal 20 via DL (Downlink) and receives a control signal or data from the terminal 20 via UL (Uplink). Both the base station 10 and the terminal 20 are capable of transmitting and receiving signals by performing beamforming. For example, as shown in FIG. 1, the reference signal transmitted from the base station 10 includes a CSI-RS (Channel State Information Reference Signal), and the channels transmitted from the base station 10 include a PDCCH (Physical Downlink Control Channel) and a PDSCH (Physical Downlink Shared Channel).

[0019] The terminal 20 is a communication device equipped with a wireless communication function, such as a smartphone, a mobile phone, a tablet, a wearable terminal, or an M2M (Machine-to-Machine) communication module. The terminal 20 receives control signals or data from the base station 10 via DL and transmits control signals or data to the base station 10 via UL, thereby utilizing various communication services provided by the wireless communication system. For example, as shown in Fig. 1, channels transmitted from the terminal 20 include a PUCCH (Physical Uplink Control Channel) and a PUSCH (Physical Uplink Shared Channel).

[0020] In NR, an antenna port is defined as a channel through which a certain symbol is transmitted at an antenna port that can be estimated from a channel through which another symbol is transmitted at the antenna port. Two antenna ports are quasi-colocated (QCL) when the propagation path characteristics of one antenna port can be estimated from the propagation path characteristics of the other antenna port, including, for example, delay spread, Doppler spread, Doppler shift, average gain, average delay, or spatial reception parameters.

[0021] Several types of QCLs are defined. QCL Type A relates to Doppler shift, Doppler spread, mean delay, and delay velocity. QCL Type B relates to Doppler shift and Doppler spread. QCL Type C relates to Doppler shift and mean delay. QCL Type D relates to spatial Rx parameters. Therefore, QCL Type A, B, or C is QCL information related to time or frequency synchronization processing, and QCL Type D is QCL information related to beam control.

[0022] Here, for example, if a certain SSB and a certain CSI-RS are QCL type D, terminal 20 can receive the SSB and the CSI-RS by applying the same receive beamforming, assuming that they are transmitted from base station 10 using the same DL beam. In the following explanation, "QCL type D" will be mainly described, but this may be replaced with QCL type A, B, or C as appropriate.

[0023] FIG. 2 is a sequence diagram illustrating an example in which a TCI state is set. In NR, TCI (Transmission configuration indicator) states are defined. A TCI state indicates the QCL relationship of a DL reference signal, and one or more TCI states are included in RRC (Radio Resource Control) signaling that sets a control resource set (CORESET). A DL reference signal is SSB or CSI-RS. That is, one of the TCI states is applied depending on a certain control resource set, and a DL reference signal corresponding to the TCI state is determined. Note that in the embodiments of the present invention, a "reference signal" may be replaced with a "synchronization signal."

[0024] In step S1, the base station 10 transmits a PDCCH-Config to the terminal 20 via RRC signaling. The PDCCH-Config includes information for the terminal 20 to receive the PDCCH, and may be notified to the terminal 20 as broadcast information or may be notified to the terminal 20 by other RRC signaling. The PDCCH-Config includes information for determining a control resource set and information for determining a search space.

[0025] In step S2, terminal 20 determines a control resource set, a search space, and a TCI state to use based on the PDCCH-Config received in step S1. Terminal 20 monitors control information in the determined search space.

[0026] In step S3, if the PDCCH-Config includes information indicating that the TCI state is notified by DCI, the base station 10 can dynamically notify the terminal 20 of the TCI state by DCI, which is PHY layer signaling. Subsequently, the terminal 20 changes to the notified TCI state (S4). Steps S3 and S4 may or may not be executed. For example, after step S4, the base station 10 and the terminal 20 execute a random access procedure. The terminal 20 estimates a QCL based on the SSB or CSI-RS selected for transmitting the PRACH, and monitors the control information.

[0027] FIG. 3 is a diagram for explaining an example of beam management. NR employs beam management as shown in FIG. 3. In beam management, beams are formed in at least one of the base station 10 and the terminal 20 to improve transmission quality. FIG. 3 shows an example of beam management in a system capable of configuring four beams on the Tx side and two beams on the Rx side. In this system, beam sweeping is performed on both the transmitting and receiving sides as shown in FIG. 3, and an appropriate beam pair is selected from a total of eight candidate patterns of transmitting and receiving beam pairs. Note that different levels of beam control, such as a rough beam and a fine beam, may also be performed.

[0028] FIG. 4 is a diagram for explaining an example of a QCL. As described above, a QCL is defined as a QCL when two signals are formed and radio parameters between the signals can be considered to be identical. FIG. 4 shows an example of a QCL association. In the QCL association, a parent-child relationship exists between a source and a destination. For example, as shown in FIG. 4, the source of QCL types C and D is an SSB, and the destination is a Tracking Reference Signal (TRS) or CSI-RS for tracking. Furthermore, the source of QCL types A and D is a TRS, and the destinations are a CSI-RS, a PDCCH DM-RS (Demodulation reference signal), and a PDSCH DM-RS.

[0029] In the existing technology, information indicating the source signal of a QCL is transmitted to a certain signal. For example, the base station 10 notifies the terminal 20 that the destination TRS is QCL type C or D, which uses SSB as the source. The signaling to transmit information about the QCL may be performed by the TCI described in FIG. 2.

[0030] When switching TCI states, if measurements have not been performed immediately before in the target TCI state, the terminal 20 cannot determine in advance the receiving beam for receiving the PDCCH or PDSCH transmitted in the target TCI state. Therefore, a "Known condition" has been defined that indicates whether measurements have been performed in a certain TCI state.

[0031] If it is a "Known condition", it indicates that a beam report or RS resource for measurement in the target TCI state has been transmitted within X ms before the TCI state switch is triggered. Otherwise, it is defined as an "Unknown condition". A suitable value for X ms is currently under consideration.

[0032] The delay when switching to a Known TCI state due to DCI is the number of symbols (timeDurationForQCL) notified in the UE capability. Note that when the TCI state is switched due to DCI, the target TCI state is already enabled in the MAC (Media Access Control) layer and monitored by the terminal 20, so the DCI will not switch to an Unknown TCI state.

[0033] The delay in switching to a known TCI state via MAC signaling is calculated using the following formula: T HARQ +3ms+TO k *(T first-SSB +T SSB-proc ) however, T HARQ : HARQ processing delay 3ms: MAC-CE decoding delay TO k : 1 if not included in the active TCI state list of PDSCH, 0 if included T first-SSB : Time until first SSB transmission after UE receives TCI status command T SSB-proc :2ms

[0034] As shown in the above equation, the delay to switch to the Known TCI state by MAC signaling is the MAC activation delay (MAC CE decoding + HARQ process delay) specified in the specification, plus one SSB transmission opportunity required to correctly set the time domain.

[0035] The delay in switching to the Unknown TCI state via MAC signaling is calculated using the following formula: T HARQ +3ms+T L1-RSRP +TO uk *(T first-SSB +T SSB-proc ) however, TL1-RSRP : L1-RSRP measurement delay for correct setting of receive beam, equivalent to L1-RSRP measurement period in one sample TO uk : 1 for CSI-RS-based L1-RSRP measurement, 0 for SSB-based L1-RSRP measurement

[0036] During the delay of switching to another TCI state via MAC signaling, the terminal 20 receives in the TCI state before the switch.

[0037] The delay in switching to a known TCI state by RRC (Radio Resource Control) signaling is calculated by the following formula. T RRC_processing +TO k *(T first-SSB +T SSB-proc ) however, T RRC_processing : RRC processing delay, i.e. 10ms

[0038] As shown in the above formula, the delay in switching to a known TCI state by RRC signaling is the RRC processing delay specified in the specifications, plus one SSB transmission opportunity required to correctly set the time domain.

[0039] The delay in switching to an unknown TCI state by RRC signaling is calculated using the following formula: T RRC_processing +T L1-RSRP +TO k *(T first-SSB +T SSB-proc )

[0040] During the delay of switching the TCI state via RRC signaling, scheduling is restricted.

[0041] The TCI state list based on MAC signaling is used when switching the active TCI state of the PDSCH by MAC signaling, and is specified in the same manner as when switching the TCI state based on MAC signaling.

[0042] Here, for example, when the base station 10 switches the transmission beam, it is necessary to switch the QCL information. For example, when the QCL information is switched, the measurement delay increases. When the QCL information is switched, the terminal 20 needs to perform time synchronization and frequency synchronization again and to re-learn the transmission / reception beam pair.

[0043] Therefore, in the embodiments of the present invention, a method for reducing the processing delay or signaling overhead associated with switching of QCL information is proposed. For example, the embodiments of the present invention reduce the processing time or number of processing steps required for synchronization of terminals 20 and the processing time or number of processing steps required for beam control.

[0044] For example, in an embodiment of the present invention, conditions are defined that do not require a QCL source, enabling synchronization directly using a QCL destination. For example, in an embodiment of the present invention, processing delays and signaling overhead can be reduced by limiting the timing of switching QCL information. Note that in an embodiment of the present invention, the QCL definition is not limited to existing QCL definitions. For example, a newly defined QCL type may be used.

[0045] For example, if the terminal 20 can synchronize solely with the reference signal that serves as the QCL destination, the terminal 20 does not need to set or refer to the reference signal that serves as the QCL source. That is, the terminal 20 may synchronize with the reference signal that serves as the QCL destination and receive a channel without referring to the reference signal that serves as the QCL source.

[0046] For example, if the density at which reference signals are multiplexed is equal to or greater than a certain value, terminal 20 does not need to configure a QCL source. The density at which reference signals are multiplexed may be the density in the time domain, the density in the frequency domain, or the CSI-RS configuration parameter density(ρ).

[0047] Furthermore, for example, if the number of resource elements on which reference signals are allocated is equal to or greater than a certain number, terminal 20 may not configure a QCL source. The number of resource elements on which reference signals are allocated may be specified by the number of resource elements per antenna port. Furthermore, for example, if the transmission bandwidth of the reference signal or the transmission bandwidth of a channel received using the reference signal is equal to or greater than a certain value, terminal 20 may not configure a QCL source. Furthermore, for example, if the number of measurement samples of the reference signal is equal to or greater than a certain number, terminal 20 may not configure a QCL source. The number of measurement samples may be specified, for example, by how many times the CSI-RS specified in the CSI-RS resource configuration can be measured within a measurement period.

[0048] The above describes conditions under which the terminal 20 does not require a QCL source. However, a condition that negates the condition under which a QCL source is not required may be defined as a condition under which a QCL source is required. For example, if the multiplexing density of the reference signal is less than a certain value, the terminal 20 may require a QCL source. For example, if the number of resource elements to which the reference signal is allocated is less than a certain number, the terminal 20 may require a QCL source. For example, if the transmission bandwidth of the reference signal or the transmission bandwidth of a channel received using the reference signal is less than a certain value, the terminal 20 may require a QCL source. For example, if the number of measurement samples of the reference signal is less than a certain number, the terminal 20 may not require a QCL source.

[0049] Furthermore, although the conditions under which terminal 20 does not require a QCL source have been described above, the conditions under which a QCL source is not required may also be defined as conditions under which a terminal can become a QCL source. For example, if the multiplexing density of a reference signal is equal to or greater than a certain value, the reference signal may be configurable as a QCL source. For example, if the number of resource elements to which a reference signal is allocated is equal to or greater than a certain number, the reference signal may be configurable as a QCL source. For example, if the transmission bandwidth of the reference signal or the transmission bandwidth of a channel received using the reference signal is equal to or greater than a certain value, the reference signal may be configurable as a QCL source. For example, if the number of measurement samples of the reference signal is equal to or greater than a certain number, the reference signal may be configurable as a QCL source.

[0050] Furthermore, although the conditions under which the terminal 20 does not require a QCL source have been described above, conditions that negate the conditions under which a QCL source is not required may also be specified as conditions under which a terminal 20 cannot become a QCL source. For example, if the multiplexing density of a reference signal is less than a certain value, the reference signal may not be configured as a QCL source. For example, if the number of resource elements to which a reference signal is allocated is less than a certain number, the reference signal may not be configured as a QCL source. For example, if the transmission bandwidth of the reference signal or the transmission bandwidth of a channel received using the reference signal is less than a certain value, the reference signal may not be configured as a QCL source. For example, if the number of measurement samples of the reference signal is less than a certain number, the reference signal may not be configured as a QCL source.

[0051] If a QCL source is set even when the above conditions for not requiring a QCL source are met, the terminal 20 may synchronize using both the reference signal serving as the QCL destination and the reference signal serving as the QCL source, or may select one of the reference signals to synchronize. For example, the terminal 20 may synchronize using the reference signal serving as the QCL source, the reference signal serving as the QCL destination, a reference signal with a high multiplexing density, or determine the reference signal to be applied depending on the signal type. For example, if the reference signal includes a TRS, the terminal 20 may synchronize by preferentially using the TRS.

[0052] A QCL relationship in the time domain may be defined, a QCL relationship with a previously transmitted signal may be defined, or the QCL relationship may be signaled.

[0053] For example, the signal in slot #n and the signal in slot #nk may be defined as having a QCL relationship. The value of k may be used to switch between having a QCL relationship or not. For example, if k<5, there may be a QCL relationship, and if k≧5, there may be no QCL relationship. A QCL relationship may also be present when the signals are of the same type (for example, DM-RS, CSI-RS, or SS). Furthermore, for example, the QCL relationship may be defined as the relationship between the signal in slot #n and the latest signal received before slot #n. The method of assuming a continuous QCL in the time domain is particularly effective in cases where beam switching is performed continuously.

[0054] 5 is a diagram showing an example (1) of switching QCL information in an embodiment of the present invention. Beam-related information (e.g., CRI (CSI-RS Resource Indicator)) notified from terminal 20 may be periodic or partial. Therefore, it is assumed that QCL switching by base station 10 may also be periodic or partial. For example, when CRI is fed back once every 10 slots, the period for switching QCL information by base station 10 may be 10 slots. By specifying the timing for switching QCL information, it is possible to reduce signaling related to the QCL.

[0055] 5, the switch timing of the QCL information may be set in the time domain. The switch timing may be notified from the base station 10 to the terminal 20. That is, it may be assumed that a signal in the same QCL duration is a QCL, and that a signal spanning the switch timing is not a QCL.

[0056] 5, the timing for switching the QCL information may be set periodically. The period and offset of the timing for switching the QCL information may be notified from the base station 10 to the terminal 20. For example, the timing for switching the QCL information may be set once every five slots. The periodic timing for switching the QCL information may be, for example, in units of 10 ms radio frames, or may be notified from the base station 10 to the terminal 20 by RRC signaling or MAC signaling.

[0057] FIG. 6 is a diagram illustrating an example (2) of switching QCL information according to an embodiment of the present invention. As illustrated in FIG. 6, the timing of switching QCL information may be set aperiodically. Whether or not to switch QCL information may be notified from base station 10 to terminal 20. For example, whether or not to switch QCL information may be notified by MAC-CE or DCI. Furthermore, the timing (e.g., a specific slot) at which QCL information is to be switched may be specified by MAC-CE or DCI. In other words, it may be notified that the signals before and after the timing at which QCL information is to be switched are not QCL. Furthermore, information related to switching QCL information may be notified only at certain times. TCI information may be notified by only certain DCIs. For example, TCI information may be notified once every 10 slots. QCL information does not need to be multiplexed in slots other than those in which TCI information is notified, and other information may be multiplexed in the payload.

[0058] FIG. 7 is a diagram showing an example (1) of notification by DCI in an embodiment of the present invention. When different TCIs are applied to a PDCCH and a PDSCH, the PDCCH and the PDSCH need to be separated in time. The time separation value is defined according to UE capabilities. For example, if there are at least 14 symbols between the scheduling DCI and the scheduled PDSCH (when SCS (Subcarrier spacing) = 120 kHz), the TCI state indicated by the scheduling DCI can be applied to the scheduled PDSCH. Since there is a time separation between the PDCCH and the PDSCH, flexible scheduling becomes difficult, for example, when a priority packet interrupts between the PDCCH and the PDSCH. On the other hand, if the time separation between the PDCCH and the PDSCH is equal to or less than a certain value, the QCL or TCI state of the CORESET (PDCCH) with the smallest ID in the latest slot is applied to the PDSCH.

[0059] Therefore, the TCI state setting and data scheduling may be performed independently. For example, as shown in Fig. 7, different DCIs may be used for the TCI state setting and data scheduling. After a control delay has elapsed since DCI #1 including TCI is received, the TCI may be applied to a PDSCH by DCI #2 including scheduling. Here, the TCI included in DCI #2 may be ignored when receiving a PDSCH by DCI #2.

[0060] When terminal 20 fails to decode DCI including TCI, it may reuse the TCI that was applied immediately before, or may apply the QCL or TCI state of the CORESET (PDCCH) with the smallest ID.

[0061] Fig. 8 is a diagram showing an example (2) of notification by DCI in an embodiment of the present invention. DCI may be signaled independently for TCI. As in Case 1 shown in Fig. 8, different TCI may be assumed for PDSCH symbols after the control delay time to which TCI is applied. In other words, TCI may be switched within a certain slot.

[0062] Also, a different TCI may be assumed for the PDSCH after the control delay time for applying the TCI, as in Case 2 shown in Fig. 8. That is, the TCI may be switched from the beginning of a certain slot.

[0063] 9 is a diagram showing an example (1) of configuring a PDCCH according to an embodiment of the present invention. When the TCI state of a PDSCH is indicated by DCI and the TCI state of a PDCCH is indicated by MAC-CE, there is a possibility that the PDSCH can reflect the latest TCI state more effectively than the PDCCH.

[0064] Therefore, as shown in FIG. 9, the TCI state of the PDCCH of DCI #2 including scheduling may be set by DCI #1 including TCI. That is, when the TCI state is indicated by DCI #1, DCI #2 detected after the control delay may assume the TCI state indicated by DCI #1. However, the method of setting the TCI state may be limited to a UE specific CORESET that is specific to terminal 20 as shown in FIG. 9. Also, similar to Case 1 shown in FIG. 8, a different TCI may be assumed for PDCCH symbols after the control delay time for applying TCI. That is, the TCI may be switched within a certain slot. Also, similar to Case 2 shown in FIG. 8, a different TCI may be assumed for PDCCH symbols after the control delay time for applying TCI. That is, the TCI may be switched from the beginning of a certain slot.

[0065] Fig. 10 is a diagram showing an example (2) of configuring a PDCCH according to an embodiment of the present invention. The TCI state configuration method shown in Fig. 9 does not need to be applied to the common CORESET shown in Fig. 10. This is because the PDCCH monitoring opportunity for the Common CORESET, i.e., the position of the time domain search space, differs depending on the TCI state. Therefore, if DCI #1 indicating a TCI is erroneously detected, the assumed TCI state changes, making it impossible to receive the time domain search space corresponding to the correct TCI state. In the case of a UE-specific CORESET, the time domain search space does not change depending on the TCI state, so the TCI state configuration method shown in Fig. 9 may be applied.

[0066] The embodiments of the present invention are applicable regardless of whether the uplink or downlink is transmitted or received. In this case, the uplink signal or channel and the downlink signal or channel can be interchanged. Furthermore, the uplink feedback information and the downlink control signaling can be interchanged.

[0067] Although the present disclosure has been described mainly on the assumption of NR channels and signaling schemes, the embodiments of the present invention can be applied to channels and signaling schemes having similar functions to NR, such as LTE / LTE-A or other RATs (Radio Access Technologies).

[0068] In this disclosure, various signaling examples have been shown, but they are not limited to explicit methods, and may be notified implicitly, or may not be signaled and may be uniquely defined by specifications.

[0069] Although various signaling examples are shown in the present disclosure, the embodiments are not limited to those shown. For example, the signaling may use signaling of different layers such as RRC, MAC-CE, and DCI, or may use MIB (Master Information Block) or SIB (System Information Block), etc.

[0070] In the present disclosure, expressions such as beam or BF (Beam forming) RS are used, but whether or not the physical signal or channel is beamformed may be transparent to the base station 10 or the terminal 20. Also, a beam may be formed in units of antenna ports. Similarly, beam selection can be rephrased as resource selection, etc., and beam index can be rephrased as resource index, antenna port index, etc.

[0071] In the present disclosure, RBs (Resource Blocks) and subcarriers can be interchanged, and similarly, slots and symbols can be interchanged.

[0072] The above-described examples and variants can be combined with each other, and the features shown in these examples can be combined with each other in various combinations. The embodiments of the present invention are not limited to the specific combinations disclosed herein.

[0073] According to the above-described embodiment, the terminal 20 can reduce processing delays and signaling associated with switching of QCL information by defining conditions that do not require a QCL source and performing synchronization that directly uses a QCL destination. Furthermore, the terminal 20 can reduce signaling by limiting the timing of QCL switching. Furthermore, the terminal 20 enables scheduling with flexible TCI state settings by independently scheduling the TCI state and data. Furthermore, the terminal 20 can reduce the delay until the TCI state is applied by applying the TCI state setting by DCI to the PDCCH.

[0074] That is, in a wireless communication system, it is possible to reduce synchronization processing related to Quasi-co-location (QCL).

[0075] (Device configuration) Next, a description will be given of an example of the functional configuration of the base station 10 and the terminal 20 that execute the processes and operations described above. The base station 10 and the terminal 20 include functions for implementing the above-described embodiments. However, the base station 10 and the terminal 20 may each include only a part of the functions of the embodiments.

[0076] <Base station 10> Fig. 11 is a diagram showing an example of the functional configuration of base station 10 in the embodiment of the present invention. As shown in Fig. 11, base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Fig. 11 is merely an example. The functional divisions and names of the functional units may be any names as long as they can perform the operations related to the embodiment of the present invention.

[0077] The transmitter 110 has a function of generating a signal to be transmitted to the terminal 20 side and transmitting the signal wirelessly. The transmitter 110 also transmits inter-network node messages to other network nodes. The receiver 120 has a function of receiving various signals transmitted from the terminal 20 wirelessly and acquiring, for example, information of higher layers from the received signals. The transmitter 110 also has a function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, etc. to the terminal 20. The receiver 120 also receives inter-network node messages from other network nodes.

[0078] The setting unit 130 stores in a storage device setting information that is set in advance and various setting information to be transmitted to the terminal 20, and reads out from the storage device as needed. The setting information includes, for example, control information for the terminal 20 and information related to the QCL.

[0079] As described in the embodiment, the control unit 140 performs processing to generate control information to be transmitted to the terminal 20. The control unit 140 also performs communication control to apply transmit beamforming based on information related to the QCL. A functional unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and a functional unit related to signal reception in the control unit 140 may be included in the receiving unit 120.

[0080] <Terminal 20> Fig. 12 is a diagram showing an example of the functional configuration of terminal 20 in the embodiment of the present invention. As shown in Fig. 12, terminal 20 has transmitting unit 210, receiving unit 220, setting unit 230, and control unit 240. The functional configuration shown in Fig. 12 is merely an example. The names of the functional divisions and functional units may be any as long as they can execute the operations related to the embodiment of the present invention.

[0081] The transmitter 210 has a function of creating a transmission signal from transmission data and transmitting the transmission signal wirelessly. The receiver 220 receives various signals wirelessly and acquires a higher layer signal from the received physical layer signal. The receiver 220 also has a function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL / SL control signals, and the like transmitted from the base station 10. For example, the transmitter 210 transmits a PSCCH (Physical Sidelink Control Channel), a PSSCH (Physical Sidelink Shared Channel), a PSDCH (Physical Sidelink Discovery Channel), a PSBCH (Physical Sidelink Broadcast Channel), and the like to another terminal 20 as D2D communication, and the receiver 120 receives the PSCCH, the PSSCH, the PSDCH, the PSBCH, and the like from the other terminal 20.

[0082] The setting unit 230 stores various setting information received from the base station 10 or the terminal 20 by the receiving unit 220 in a storage device, and reads it out from the storage device as needed. The setting unit 230 also stores setting information that is set in advance. The content of the setting information includes, for example, control information for the terminal 20 and information related to QCL.

[0083] As described in the embodiments, the control unit 240 applies receive beamforming and performs synchronization processing based on the control information and QCL information acquired from the base station 10. The control unit 240 may also control a random access procedure with the base station 10. A functional unit related to signal transmission in the control unit 240 may be included in the transmitting unit 210, and a functional unit related to signal reception in the control unit 240 may be included in the receiving unit 220.

[0084] (Hardware configuration) The block diagrams (FIGS. 11 and 12) 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 connected directly or indirectly (for example, by wire, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining the single device or the multiple devices with software.

[0085] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocation, 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.

[0086] For example, the base station 10, the terminal 20, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 13 is a diagram illustrating an example of the hardware configuration of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. The base station 10 and the terminal 20 described above may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0087] In the following description, the term "apparatus" can be read 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.

[0088] Each function in the base station 10 and the terminal 20 is realized by loading predetermined software (programs) onto hardware such as the processor 1001, the memory device 1002, etc., so that the processor 1001 performs calculations, controls communication by the communication device 1004, and controls at least one of reading and writing data in the memory device 1002 and the auxiliary memory device 1003.

[0089] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured as 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 140, control unit 240, etc. may be realized by the processor 1001.

[0090] Furthermore, the processor 1001 reads programs (program codes), software modules, data, etc. from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002, and executes various processes in accordance with the programs. 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 140 of the base station 10 shown in FIG. 11 may be implemented by a control program stored in the storage device 1002 and running on the processor 1001. Furthermore, for example, the control unit 240 of the terminal 20 shown in FIG. 12 may be implemented by a control program stored in the storage device 1002 and running on the processor 1001. 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 be transmitted from a network via a telecommunications line.

[0091] The storage device 1002 is a computer-readable recording medium and may be configured, for example, by 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 storage device 1002 may also be called a register, a cache, a main memory, etc. The storage device 1002 can store executable programs (program codes), software modules, etc. for implementing a communication method according to an embodiment of the present disclosure.

[0092] The secondary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of 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® disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. The above-mentioned recording medium may be, for example, a database, a server, or other suitable medium including at least one of the storage device 1002 and the secondary storage device 1003.

[0093] 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, or a communication module. 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, a transmission / reception antenna, an amplifier unit, a transmission / reception unit, a transmission path interface, etc. may be realized by the communication device 1004. The transmission / reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated.

[0094] The input device 1005 is an input device (for example, 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 (for example, a display, a speaker, an LED lamp, etc.) that performs output to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0095] Furthermore, each device such as the processor 1001 and the storage device 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.

[0096] Furthermore, base station 10 and 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, processor 1001 may be implemented using at least one of these pieces of hardware.

[0097] (Summary of the embodiment) As described above, according to an embodiment of the present invention, there is provided a terminal having a control unit that performs synchronization using a reference signal associated with a channel without referring to a Quasi-co-location (QCL) source of the reference signal when the reference signal satisfies a condition, and a receiving unit that receives the channel after the control unit has synchronized using the reference signal.

[0098] With the above configuration, the terminal 20 can reduce processing delays and signaling associated with switching of QCL information by performing synchronization directly using the QCL destination under conditions that do not require the QCL source. That is, the synchronization process related to Quasi-co-location (QCL) can be reduced in the wireless communication system.

[0099] The condition may be that the density at which the reference signal is multiplexed is equal to or greater than a certain value, that the number of resource elements to which the reference signal is allocated is equal to or greater than a certain value, or that the number of measurement samples of the reference signal is equal to or greater than a certain value. With this configuration, the terminal 20 can reduce processing delays and signaling associated with switching of QCL information by defining a condition that does not require a QCL source and performing synchronization that directly uses a QCL destination.

[0100] The control unit may perform synchronization by assuming that a signal received at a certain time point and a signal received before the certain time point are QCLs. With this configuration, the terminal 20 can reduce signaling associated with QCL switching.

[0101] The control unit may perform synchronization on the assumption that the QCL information is switched periodically. With this configuration, the terminal 20 can reduce signaling by limiting the timing of QCL switching.

[0102] The control unit may perform synchronization based on control information including the QCL information, which is received in a time domain different from control information for scheduling a channel to which the QCL information is applied. With this configuration, the terminal 20 performs scheduling of the TCI state and data independently, thereby enabling scheduling with flexibly set TCI states.

[0103] Furthermore, according to an embodiment of the present invention, there is provided a communication method in which, if a reference signal associated with a channel satisfies a condition, a control procedure is performed to perform synchronization using the reference signal without referring to a Quasi-co-location (QCL) source of the reference signal, and a reception procedure is performed in which a terminal receives the channel after synchronizing using the reference signal through the control procedure.

[0104] With the above configuration, the terminal 20 can reduce processing delays and signaling associated with switching of QCL information by performing synchronization directly using the QCL destination under conditions that do not require the QCL source. That is, the synchronization process related to Quasi-co-location (QCL) can be reduced in the wireless communication system.

[0105] (Supplementary explanation of the embodiment) Although the embodiments of the present invention 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 invention; two or more items may be combined as needed, and items described in one item may apply to items described in another item (unless inconsistent). The boundaries between functional units or processing units in the functional block diagram do not necessarily correspond to the 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 the processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, the base station 10 and terminal 20 have been described using functional block diagrams. However, such devices may be implemented using hardware, software, or a combination thereof. The software operated by the processor of the base station 10 in accordance with an embodiment of the present invention and the software operated by the processor of the terminal 20 in accordance with an embodiment of the present invention may each be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server or any other suitable storage medium.

[0106] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), 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), System Information Block (SIB)), other signals, or a combination thereof. Furthermore, the 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.

[0107] Each aspect / embodiment described in the present disclosure may be applied to at least one of systems using LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (New Radio), 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 802.20, UWB (Ultra-Wideband), Bluetooth (registered trademark), or other appropriate systems, and next-generation systems extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G, etc.) may also be applied.

[0108] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described herein may be changed unless it is consistent. 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.

[0109] In this specification, a specific operation that is described as being performed by the base station 10 may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having the base station 10, it is clear that various operations performed for communication with the terminal 20 may be performed by at least one of the base station 10 and another network node other than the base station 10 (such as, but not limited to, an MME or an S-GW). Although the above example illustrates a case where there is one other network node other than the base station 10, the other network node may be a combination of multiple other network nodes (such as an MME and an S-GW).

[0110] The information or signals described in the present disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input / output via multiple network nodes.

[0111] Input and output information may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information may be overwritten, updated, or added to. Output information may be deleted. Input information may be sent to another device.

[0112] In the present disclosure, the determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0113] 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.

[0114] 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.

[0115] The 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. that 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.

[0116] Note that terms explained 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.

[0117] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0118] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0119] 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.

[0120] In the present disclosure, terms such as "base station (BS)," "radio base station," "base station device," "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. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0121] 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 divided into multiple smaller areas, and each smaller area can be provided with communication service by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head)). The term "cell" or "sector" refers to a part or the entire coverage area of ​​a base station and / or base station subsystem that provides communication service within this coverage.

[0122] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0123] 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.

[0124] At least one of the base station and the mobile station may be called 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 body, or the mobile body itself. The mobile body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (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 also include devices that do 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.

[0125] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between a plurality of terminals 20 (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). In this case, the terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0126] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station may be configured to have the functions of the user terminal described above.

[0127] 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 in a table, database, or other data structure), ascertaining, 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. 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.

[0128] 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.

[0129] The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0130] 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."

[0131] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. 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 in some way precede the second element.

[0132] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0133] When used in this disclosure, the terms "include," "including," and variations thereof are intended to be inclusive, similar to the term "comprising." Furthermore, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0134] 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.

[0135] Numerology may be communication parameters that apply to at least one of transmission and reception of a signal or channel, such as 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.

[0136] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol) in the time domain. A slot may be a time unit based on numerology.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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 wireless resources (such as frequency bandwidth and transmission power that can be used by each terminal 20) to each terminal 20 in TTI units. Note that the definition of TTI is not limited to this.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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 equal to or greater than 1 ms.

[0145] A resource block (RB) is a resource allocation unit in the time domain and 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 also be determined based on numerology.

[0146] 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.

[0147] 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, or the like.

[0148] 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.

[0149] 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 given BWP and numbered within that BWP.

[0150] 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.

[0151] 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."

[0152] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, 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. may be changed in various ways.

[0153] 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.

[0154] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." 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."

[0155] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, 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).

[0156] In the present disclosure, the PDSCH or the PDCCH is an example of a channel, and the DCI is an example of control information.

[0157] 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.

[0158] <Additional Notes> The above-described embodiment can be further described as follows.

[0159] (Appendix 1) a control unit that performs synchronization using a reference signal associated with a channel if the reference signal satisfies a condition without reference to a Quasi-co-location (QCL) source of the reference signal; A terminal having a receiver that receives the channel after the controller is synchronized using the reference signal.

[0160] (Appendix 2) The terminal according to Supplementary Note 1, wherein the condition is that the density at which the reference signal is multiplexed is greater than or equal to a certain value, the number of resource elements to which the reference signal is allocated is greater than or equal to a certain value, or the number of measurement samples of the reference signal is greater than or equal to a certain value.

[0161] (Appendix 3) 2. The terminal according to claim 1, wherein the control unit performs synchronization by assuming that a signal received at a certain point in time and a signal received before the certain point in time are QCL.

[0162] (Appendix 4) 2. The terminal according to claim 1, wherein the control unit performs synchronization assuming that QCL information is switched periodically.

[0163] (Appendix 5) 2. The terminal according to claim 1, wherein the control unit performs synchronization based on control information including the QCL information that is received in a different time domain from control information that schedules a channel to which the QCL information is applied.

[0164] (Appendix 6) a control procedure for performing synchronization using a reference signal associated with a channel if the reference signal satisfies the condition, without reference to a Quasi-co-location (QCL) source of the reference signal; A communication method in which a terminal executes a receiving procedure to receive the channel after synchronization using the reference signal by the control procedure. [Explanation of symbols]

[0165] 10 base station 110 Transmitter 120 Receiver 130 Setting section 140 Control Unit 20 terminals 210 Transmitter 220 Receiving unit 230 Setting Section 240 Control Unit 1001 processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication equipment 1005 Input Device 1006 Output Device

Claims

1. a receiving unit that receives first DCI (Downlink Control Information) and second DCI; a control unit that applies a TCI (Transmission configuration indicator) state notified by the first DCI to reception of a data channel scheduled by the second DCI; The terminal, wherein the control unit applies the TCI state to reception of the second DCI when the second DCI is received after a certain period of time has elapsed since receiving the first DCI.

2. The terminal according to claim 1 , wherein the control unit applies the TCI state to reception of the data channel when the data channel is received after a certain period of time has elapsed since receiving the first DCI.

3. The terminal according to claim 1 , wherein the control unit does not apply the TCI state notified by the second DCI to reception of the data channel.

4. The terminal according to claim 1 , wherein the control unit switches the TCI state applied to reception of the data channel from the beginning of a slot to the TCI state notified by the first DCI.

5. A terminal as described in claim 1, wherein the receiving unit receives the second DCI in a terminal-specific CORESET (Control resource set).

6. receiving a first DCI (Downlink Control Information) and a second DCI; applying a transmission configuration indicator (TCI) state indicated by the first DCI to reception of a data channel scheduled by the second DCI; and a procedure of applying the TCI state to reception of the second DCI when the second DCI is received after a certain period of time has elapsed since reception of the first DCI.

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