Base station, communication method, and integrated circuit

Abstract

The present invention improves transmission efficiency in unlicensed bands. This base station comprises: a control circuit for determining a cyclic prefix (CP) length coordinated between a terminal and the base station; and a transmission circuit for transmitting control information regarding the determined CP length to the terminal.

Description

Technical Field

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

Background Art

[0002] In the 3rd Generation Partnership Project (3GPP), as an enhancement of the 5th Generation mobile communication systems (5G), the specification of the physical layer of Release 16 NR (New Radio access technology) has been completed. In NR, in addition to the advancement of mobile broadband (eMBB: enhanced Mobile Broadband) to meet requirements such as high speed and large capacity, a function to realize Ultra Reliable and Low Latency Communication (URLLC) is supported (see, for example, Non-Patent Documents 1-5).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Summary of the Invention

[0004] However, there is room for study on the communication method in the unlicensed band.

[0005] Non-limiting embodiments of the present disclosure contribute to providing a base station, a terminal, and a communication method capable of improving the transmission efficiency in the unlicensed band.

[0006] A base station according to an embodiment of the present disclosure includes a control circuit that determines a cyclic prefix (CP) length coordinated between a terminal and the base station, and a transmission circuit that transmits control information regarding the determined CP length to the terminal.

[0007] These general or specific aspects may be implemented in a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be implemented in any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0008] According to an embodiment of the present disclosure, the transmission efficiency in the unlicensed band can be improved.

[0009] Further advantages and effects in an embodiment of the present disclosure will be clarified from the specification and the drawings. Such advantages and / or effects are provided by some embodiments and the features described in the specification and the drawings, respectively, but it is not necessarily required that all of them be provided to obtain one or more identical features.

Brief Description of the Drawings

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Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0012] [Unlicensed Frequency Band] In Release 16 NR, for example, the introduction of NR-Unlicensed (also referred to as NR-U), which performs communication based on the radio access method of NR in an unlicensed frequency band (or also referred to as an unlicensed band), is considered.

[0013] In an unlicensed frequency band, for example, each device performs carrier sense (also referred to as Listen Before Talk (LBT)), which checks whether another system, terminal, etc. is using the radio channel before transmission.

[0014] Also, in Release 17 NR, in the unlicensed frequency band, for example, extensions for operating ultra-reliable and low-latency communications (URLLC) services are considered. One of the extensions is, for example, in Frame based equipment (FBE), which is one of the channel access methods, the operation for a terminal (also called User Equipment (UE) for example) to obtain the channel occupancy time (for example, COT: Channel Occupancy Time) (for example, UE-initiated COT) is considered. Note that FBE is also called semi-static channel occupancy for example.

[0015] However, the scheduling method in UE-initiated COT has not been fully studied.

[0016] FIG. 1 is a diagram showing an example of channel access by FBE. In the FBE of Release 16 NR-U, for example, as shown in FIG. 1, a base station (also called gNB for example) may obtain the COT by performing LBT (for example, Category 2 LBT) at the beginning of a period called Fixed frame period (FFP). The terminal may obtain the COT by performing Category 2 or Category 1 LBT within the COT of the base station (also called gNB COT for example).

[0017] In Load Based Equipment (LBE), which is another channel access method different from FBE, for example, it is possible to attempt to obtain the COT at any timing. On the other hand, in LBE, for example, Category 4 LBT with a longer LBT period may be performed compared to Category 1 or Category 2.

[0018] Thus, FBE can acquire COT in a short LBT period compared to, for example, LBE. On the other hand, in FBE, for example, as shown in FIG. 1, an "Idle period" is provided, which is a period during which both the base station and the terminal cannot transmit (for example, a period during which COT cannot be acquired).

[0019] [Configured grant transmission] The Configured grant transmission supported in Release 15 NR (for example, Configured grant transmission in a licensed frequency band) will be described.

[0020] The Configured grant transmission of uplink data (for example, PUSCH: Physical Uplink Shared Channel) includes, for example, "Configured grant type 1 transmission" and "Configured grant type 2 transmission".

[0021] In Configured grant type 1 transmission, for example, information such as the coding and modulation scheme (MCS: Modulation and Coding Scheme), radio resource allocation (for example, allocation of at least one of time resource and frequency resource), transmission timing, and the number of Hybrid Automatic Repeat Request (HARQ) processes (for example, called Configured grant setting information or CG setting information) may be set (in other words, notified or instructed) to the terminal by a higher layer signal specific to the terminal. For example, when uplink data occurs, the terminal may transmit uplink data (for example, PUSCH) based on CG setting information such as a preset MCS and radio resources without a UL grant (for example, scheduling information for dynamic uplink data) from the base station via a downlink control channel (for example, PDCCH: Physical Downlink Control Channel).

[0022] Note that the upper layer signal may also be referred to as, for example, a Radio Resource Control (RRC) signal, higher layer signaling, or higher layer parameter.

[0023] Also, in Configured grant type 2 transmission, for example, the Configured grant transmission is activated or released by a PDCCH from a base station. In Configured grant type 2 transmission, information such as transmission timing and the number of HARQ processes may be set by a terminal-specific upper layer signal in the same manner as in Configured grant type 1 transmission. On the other hand, in Configured grant type 2 transmission, information such as MCS and radio resource allocation information may be set by downlink control information (DCI) for activation. When uplink data is generated, for example, the terminal may semi-permanently (in other words, statically or semi-statically) use CG setting information such as MCS and radio resources set by the upper layer signal and the DCI for activation (in other words, without a UL grant or UL grant free) to transmit uplink data (for example, PUSCH).

[0024] Also, in Release 15 NR, for example, a UL grant is used for retransmission control of Configured grant transmission. For example, the MCS and radio resource allocation information for retransmission uplink data may be controlled by the UL grant.

[0025] Also, the HARQ process number (or HARQ process ID) used in Configured grant transmission may be uniquely determined, as a non-limiting example, from the slot number for transmitting PUSCH (in other words, the transmission timing of PUSCH). For example, the PUSCH transmitted in Configured grant transmission may be treated in the same way as the signal transmitted for the first time, and the Redundancy Version (RV) may be 0.

[0026] [Configured grant transmission in unlicensed frequency band] In Configured grant transmission in NR-U (NR in unlicensed frequency band), for example, some of the parameters used for decoding PUSCH (such as parameters related to retransmission control), such as the HARQ process number, New Data Indicator (NDI), and RV, may be notified from the terminal to the base station by the uplink control information for Configured grant transmission (for example, called CG-UCI: Configured grant Uplink Control Information).

[0027] CG-UCI may be transmitted at the same transmission timing (for example, the same slot) as PUSCH, using, for example, a part of the radio resources allocated to PUSCH (which may also be called CG-PUSCH). In other words, CG-UCI may be multiplexed with CG-PUSCH.

[0028] Here, in NR-U, the reason for explicitly notifying the HARQ process number using CG-UCI is as follows. For example, in NR-U, depending on the result of LBT, PUSCH may not be transmitted. Therefore, for example, in a method of determining the HARQ process number associated with the transmission timing of PUSCH such as in a licensed frequency band, the HARQ process may not be utilized flexibly depending on whether the PUSCH is actually transmitted. Thus, the HARQ process number can be notified using, for example, CG-UCI transmitted together with CG-PUSCH.

[0029] Also, in NR-U, for example, the operation of the terminal retransmitting using the radio resources configured for Configured grant without a UL grant is supported due to, for example, receiving a NACK or timer expiration. Therefore, for example, information indicating the state of the first transmission or retransmission (e.g., NDI), and the RV applied to the PUSCH at the time of retransmission may be transmitted by CG-UCI.

[0030] In NR-U, for example, the HARQ-ACK feedback for CG-PUSCH may be explicitly notified from the base station to the terminal by information called Downlink Feedback Indicator (DFI). For CG-PUSCH, for example, the HARQ process number is notified by CG-UCI. Therefore, for example, if the base station fails to receive CG-UCI, the base station may not be able to identify which HARQ process the data was transmitted for, and may not be able to instruct the retransmission of PUSCH by specifying the HARQ process. Thus, the base station may, for example, notify (in other words, feedback) the HARQ-ACK feedback information for all HARQ processes. Also, the base station can reduce the overhead due to LBT and improve the efficiency of retransmission control by, for example, collectively feedbacking the HARQ-ACK feedback information for a plurality of PUSCHs to the terminal.

[0031] In the retransmission control by DFI, the MCS and radio resource allocation of the PUSCH for retransmission may be the same as those at the first transmission. Also, the DFI may be transmitted, for example, in the PDCCH. Further, the DFI may include other parameters such as a transmission power control (TPC) command in addition to, for example, HARQ-ACK.

[0032] [CP extension in CG-PUSCH] In CG-PUSCH transmission, for example, even if transmission resources are allocated to the terminal, if the terminal does not have transmission data, PUSCH transmission is not performed. When PUSCH transmission is not performed, the resources allocated to the terminal are not used, so the resource utilization efficiency may decrease.

[0033] Therefore, for example, a method of allocating a plurality of terminals to the same CG resource and sharing the resources has been studied. In resource sharing by a plurality of terminals, for example, if a plurality of terminals transmit simultaneously on the shared resource, a collision may occur and there is a possibility that the signals of each terminal cannot be correctly received at the base station. Therefore, as a mechanism for avoiding collisions, for example, a mechanism for setting different transmission start timings for each terminal using "CP extension" has been introduced.

[0034] Note that hereinafter, the CP extension used in the mechanism for setting different transmission start timings for each terminal is referred to as "CP extension for multiple transmission timings".

[0035] Figure 2 shows an example of CP extension for multiple transmission timings. In the example shown in Figure 2, it shows the CP extension when starting the transmission of PUSCH (for example, useful symbol) at Symbol N. Also, in Figure 2, as an example, the subcarrier spacing (SCS) is 15 kHz, and T shown in Figure 2 may correspond to 1 symbol. As shown in Figure 2, by setting different CP extension amounts (or also referred to as extension amount, CP extension length, CP length) such as "T - 16us", "T - 25us",... "T - 61us" or "0 us" for each terminal, the transmission start timing may be different among terminals.

[0036] For example, a case will be described where there is another terminal (for example, terminal B) whose transmission start timing (for example, an extension amount less than that of terminal A) is set later than the transmission start timing of a certain terminal (for example, terminal A). In this case, if terminal A starts transmission earlier than terminal B, terminal B will perform carrier sense (for example, LBT), and as a result, the channel will be busy and it will not start transmission.

[0037] In this way, with CP extension for multiple transmission timings, by setting different CP extension amounts among terminals, it is possible to suppress collisions (in other words, the occurrence of interference) in transmission among terminals.

[0038] [CP extension in Dynamic Grant (DG)-PUSCH] In channel access in an unlicensed band, depending on the type of LBT (for example, category), the gap from the previous transmission (for example, the period when no transmission is performed) may be set to a specified length (or less than the specified length). For example, the gap from the previous transmission may be set to 16us or 25us.

[0039] Therefore, in DG-PUSCH, for example, a CP extension amount for adjusting the gap with the previous transmission may be set using a UL grant.

[0040] Note that hereinafter, the CP extension used for gap adjustment with the previous transmission is referred to as "CP extension for gap adjustment".

[0041] In the CP extension for gap adjustment, the CP extension amount may be set (e.g., jointly encoded) together with the Channel Access Type (or also referred to as LBT Type) and the Channel access priority type (CAPC) in, for example, DCI format 0_1.

[0042] FIG. 3 is a diagram showing an example of the CP extension amount (or candidate CP extension amount) that can be set for the CP extension for gap adjustment. In FIG. 3, C1 is a value set based on the subcarrier spacing (SCS), and C2 and C3 are values set by higher layer signaling. Also, TA indicates Timing alignment. Since the transmission timing of PUSCH at the terminal is adjusted to match the transmission and reception timing of the base station, it may be set earlier by TA with respect to the reception timing of the terminal. On the other hand, since gap adjustment is performed based on the transmission and reception timing of the terminal (e.g., to adjust the period from when the terminal receives to when it transmits), TA may be included in the CP extension for gap adjustment for the purpose of subtracting the influence of TA. Thus, the CP extension for gap adjustment may include a candidate CP extension amount with the influence of TA subtracted (in other words, a CP extension amount calculated based on TA). However, for example, when transmitting following an uplink transmission, TA is not subtracted during gap adjustment, so not all candidate CP extension amounts need to be calculated based on TA.

[0043] For example, before transmitting PUSCH, the terminal may perform a CP extension in response to the notification of the CP extension for gap adjustment.

[0044] [Scheduling of UE-initiated COT] When semi-statically scheduling UE-initiated COT (in other words, when the FFP for the terminal to acquire COT is semi-statically allocated), the transmission delay time of the base station (or the terminal) may increase. For example, if COT acquisition (in other words, transmission start) is set at the beginning of a certain FFP for terminal A and terminal A has no transmission data, even if another terminal B (or the base station) has transmission data (however, if terminal B does not have COT acquisition set in the said FFP), terminal A can transmit while terminal B cannot transmit, so the delay time of terminal B may increase.

[0045] Also, in FBE, COT acquisition is possible at the beginning of the FFP, and the COT acquisition timing may not be set at a timing different from the beginning of the FFP (see, for example, ETSI EN 301 893). Therefore, even if there is no transmission data at the beginning of the FFP, if transmission can occur from the middle of the FFP in the terminal, it is assumed that COT acquisition is performed at the beginning of the FFP.

[0046] Thus, based on the fact that the COT acquisition timing is at the beginning of the FFP (for example, the constraint of COT acquisition), a UE-initiated COT scheduling method for a terminal having data to acquire COT is expected.

[0047] Therefore, in one embodiment of the present disclosure, a method for improving transmission efficiency when UE-initiated COT scheduling is performed in an unlicensed frequency band will be described.

[0048] (Embodiment 1) [Overview of the communication system] A communication system according to an aspect of the present disclosure may include, for example, a base station 100 (e.g., gNB) shown in FIGS. 4 and 6, and a terminal 200 (e.g., UE) shown in FIGS. 5 and 7. A plurality of base stations 100 and terminals 200 may exist in the communication system, respectively.

[0049] FIG. 4 is a block diagram showing a partial configuration example of the base station 100 according to an aspect of the present disclosure. In the base station 100 shown in FIG. 4, a scheduling unit 104 (e.g., corresponding to a control circuit) determines a coordinated CP length (e.g., CP extension amount) between the terminal 200 and the base station 100. A transmission unit 109 (e.g., corresponding to a transmission circuit) transmits control information (e.g., CP extension setting information) regarding the determined CP length to the terminal 200.

[0050] FIG. 5 is a block diagram showing a partial configuration example of the terminal 200 according to an aspect of the present disclosure. In the terminal 200 shown in FIG. 5, a reception unit 201 (e.g., corresponding to a reception circuit) receives control information (e.g., CP extension setting information) regarding a coordinated CP length between the terminal 200 and the base station 100. A transmission control unit 204 (e.g., corresponding to a control circuit) controls uplink transmission (e.g., COT acquisition timing or transmission start timing) based on the CP length.

[0051] [Configuration of Base Station] FIG. 6 is a block diagram showing a configuration example of the base station 100 according to an aspect of the present disclosure. In FIG. 6, the base station 100 includes a reception unit 101, a demodulation / decoding unit 102, a carrier sense unit 103, a scheduling unit 104, a control information holding unit 105, a data / control information generation unit 106, an encoding / modulation unit 107, a Cyclic Prefix (CP) addition unit 108, and a transmission unit 109.

[0052] The receiving unit 101 performs reception processing such as down-conversion or A / D conversion on the received signal received via an antenna, for example, and outputs the received signal after the reception processing to the demodulation / de-coding unit 102 and the carrier sense unit 103. The received signal may include, for example, a signal transmitted from the terminal 200 (for example, an uplink signal), or a signal of another system.

[0053] The demodulation / de-coding unit 102 demodulates and de-codes, for example, the received signal (for example, an uplink signal) input from the receiving unit 101, and outputs the de-coding result to the scheduling unit 104.

[0054] The carrier sense unit 103 may perform carrier sense (for example, LBT) based on the received signal input from the receiving unit 101, for example. For example, the carrier sense unit 103 may determine whether the channel state is "busy" or "idle" (in other words, whether the channel is available) based on the received signal input from the receiving unit 101. The carrier sense unit 103 outputs information indicating the determined channel state to the scheduling unit 104.

[0055] The scheduling unit 104 determines, for example, the CP extension setting information (which may include, for example, the CP extension amount), the Configured grant (CG) setting information, or the FBE setting information (which may include, for example, the FFP period or timing) for the terminal 200, and outputs the determined CP extension setting information, CG setting information, or FBE setting information to the control information holding unit 105.

[0056] Further, the scheduling unit 104 may, for example, instruct the data / control information generation unit 106 to generate data or control information based on the decoding result input from the demodulation / de - coding unit 102. Also, when transmitting signaling information including, for example, CP extension setting information, CG setting information, or FBE setting information, the scheduling unit 104 may instruct the data / control information generation unit 106 to generate the signaling information. Further, the scheduling unit 104 may, for example, output information regarding the CP extension amount during downlink transmission to the CP addition unit 108. Also, the scheduling unit 104 may, for example, determine whether to perform transmission based on the information indicating the channel state input from the carrier sense unit 103, and output a transmission instruction to the transmission unit 109 based on the determination result.

[0057] The control information holding unit 105 holds control information such as CP extension setting information or CG setting information for each terminal 200. The control information holding unit 105 may, for example, output the held information to each component of the base station 100 (for example, the scheduling unit 104) as necessary.

[0058] The data / control information generation unit 106 generates data or control information according to an instruction from the scheduling unit 104, and outputs a signal including the generated data or control information to the encoding / modulation unit 107. For example, the data / control information generation unit 106 may generate data including signaling information based on the generation instruction of the signaling information input from the scheduling unit 104, and output the generated data to the encoding / modulation unit 107.

[0059] The encoding / modulation unit 107 encodes and modulates the signal input from the data / control information generation unit 106, and outputs the modulated transmission signal (for example, a signal in the time domain) to the CP addition unit 108.

[0060] The CP addition unit 108 adds CP to the time-domain signal input from the encoding / modulation unit 107 based on, for example, the CP extension amount input from the scheduling unit 104, and outputs the signal after CP addition to the transmission unit 109.

[0061] The transmission unit 109 performs transmission processing such as D / A conversion, up-conversion, or amplification on the signal input from the CP addition unit 108, for example. Also, the transmission unit 109 transmits the radio signal obtained by the transmission processing from the antenna to the terminal 200 based on, for example, the transmission instruction from the scheduling unit 104.

[0062] [Configuration of the terminal] FIG. 7 is a block diagram showing a configuration example of a terminal 200 according to an aspect of the present disclosure. In FIG. 7, the terminal 200 includes a reception unit 201, a demodulation / decoding unit 202, a carrier sense unit 203, a transmission control unit 204, a control information holding unit 205, a data / control information generation unit 206, an encoding / modulation unit 207, a CP addition unit 208, and a transmission unit 209.

[0063] The reception unit 201 performs reception processing such as down-conversion or A / D conversion on the reception signal received via the antenna, for example, and outputs the reception signal after reception processing to the demodulation / decoding unit 202 and the carrier sense unit 203. The reception signal may include, for example, a signal transmitted from the base station 100 (e.g., a downlink signal), or a signal of another system.

[0064] The demodulation / decoding unit 202 demodulates and decodes the reception signal (e.g., a downlink signal) input from the reception unit 201, for example, and outputs the decoding result to the transmission control unit 204. The decoding result may include, for example, downlink control information (e.g., UL grant, Slot format information, or COT information).

[0065] The carrier sense unit 203 may perform carrier sense (or LBT) based on, for example, the received signal input from the receiving unit 201. For example, the carrier sense unit 203 may determine whether the channel state is "busy" or "idle" (in other words, whether the channel is available) based on the received signal input from the receiving unit 201. The carrier sense unit 203 outputs information indicating the determined channel state to the transmission control unit 204.

[0066] The transmission control unit 204 outputs, for example, the signaling information (e.g., CP extension setting information, CG setting information, or FBE setting information) included in the decoding result input from the demodulation / decoding unit 202 to the control information holding unit 205. Also, the transmission control unit 204 may instruct the data / control information generation unit 206 to generate data or control information based on, for example, the control information such as CG setting information input from the control information holding unit 205 or the downlink control information input from the demodulation / decoding unit 202. Further, the transmission control unit 204 may determine the CP extension amount during uplink transmission based on, for example, the CP extension setting information and output information regarding the CP extension amount to the CP addition unit 208. Also, the transmission control unit 204 may determine whether to perform transmission based on the information indicating the channel state input from the carrier sense unit 203 and output a transmission instruction to the transmission unit 209 based on the determination result.

[0067] The control information holding unit 205 holds control information such as the signaling information (e.g., CP extension setting information or CG setting information) input from the transmission control unit 204 and outputs the held information to each component (e.g., the transmission control unit 204) as necessary.

[0068] The data / control information generation unit 206 generates data or control information according to an instruction from the transmission control unit 204, for example, and outputs a signal including the generated data or control information to the encoding / modulation unit 207.

[0069] The symbolization / modulation unit 207 encodes and modulates, for example, the signal input from the data / control information generation unit 206, and outputs the modulated transmission signal (for example, a signal in the time domain) to the CP addition unit 208.

[0070] The CP addition unit 208 adds CP to the time-domain signal input from the symbolization / modulation unit 207 based on, for example, the CP extension amount input from the transmission control unit 204, and outputs the signal after CP addition to the transmission unit 209.

[0071] The transmission unit 209 performs transmission processing such as D / A conversion, up-conversion, or amplification on the signal input from the CP addition unit 208. Also, the transmission unit 209 transmits, for example, the radio signal obtained by the transmission processing from the antenna to the base station 100 based on the transmission instruction from the transmission control unit 204.

[0072] [Operations of Base Station 100 and Terminal 200] An operation example in the base station 100 and terminal 200 having the above configuration will be described.

[0073] FIG. 6 is a sequence diagram showing an operation example of the base station 100 and the terminal 200.

[0074] The base station 100 determines, for example, a CP extension setting for the terminal 200 (S101). The CP extension setting may include information regarding, for example, the CP extension amount (for example, CP length) to be set for the terminal 200.

[0075] The base station 100 transmits control information to the terminal 200 (S102). The control information may include, for example, at least CP extension setting information. The CP extension setting information may be notified to the terminal 200 by at least one of a higher layer signal (e.g., RRC signal) and DCI. For example, the CP extension setting information may be set to the terminal 200 by a higher layer signal and may be dynamically notified to the terminal 200 by DCI. Or, the CP extension setting information may be such that, for example, a plurality of candidate CP extension amounts are set to the terminal 200 by a higher layer signal, and DCI including a control value (or index) corresponding to any one of the candidate CP extension amounts may be notified to the terminal 200.

[0076] The terminal 200 may perform, for example, carrier sense (e.g., LBT) (S103). The terminal 200 may set a CP extension for an uplink signal based on, for example, the CP extension setting information. Then, the terminal 200 may perform carrier sense at a transmission start timing corresponding to the CP extension.

[0077] The terminal 200 may transmit an uplink signal, for example, when the result of carrier sense for a channel is idle (S104).

[0078] [COT Acquisition Control Method] An example of a method for controlling COT acquisition in the base station 100 (e.g., the scheduling unit 104) will be described. The terminal 200 (e.g., the transmission control unit 204) may control COT acquisition and uplink transmission (e.g., PUSCH transmission) based on the control by the base station 100, for example.

[0079] In this embodiment, for example, the period and duration of the FFP may be common between the base station 100 and the terminal 200. Also, in this embodiment, for example, a period during which CP extension is possible may be set before the start of the FFP (for example, immediately before the start of the FFP). Note that the period during which CP extension can be set is not limited to the period before the start of the FFP, and may be, for example, a period after the start of the FFP (for example, immediately after the start of the FFP), or a period including the start of the FFP (for example, a period spanning multiple FFPs).

[0080] FIG. 9 is a diagram showing an example in which a period during which CP extension can be set is set immediately before the start of the FFP. Note that the Idle period may be set to be, for example, longer than a specified length (for example, 5% or more of the FFP, or 100 us or more) when the above-described period during which CP extension can be set is set.

[0081] The base station 100 may, for example, set the CP extension amount for each terminal 200 that may transmit during the period during which CP extension can be set, and notify the terminal 200 of the CP extension setting information indicating the CP extension amount. The transmission start timing of each terminal 200 may be determined according to the CP extension amount set by the base station 100.

[0082] When transmitting, the terminal 200 may, for example, wait until the transmission start timing based on the CP extension amount instructed by the base station 100, and start transmission when the channel is idle as a result of carrier sensing. For example, the terminal 200 that starts transmission may be the terminal that has acquired the COT in each FFP (for example, the terminal that has acquired the COT first). Note that when multi-transmission in the frequency domain or the spatial domain is possible, a plurality of terminals 200 may start transmission within the FFP. In other words, there may be a plurality of terminals 200 that acquire the COT in each FFP.

[0083] Also, in a certain FFP, after the transmission of the terminal 200 is completed, if there is remaining time available for transmission within the FFP excluding the idle period, the base station 100 may perform downlink transmission after the transmission of the terminal 200.

[0084] Also, for example, when the base station 100 performs COT acquisition and downlink transmission at the beginning of the FFP, the CP extension amount and the transmission start timing may be determined based on the priority of the transmission of the base station 100 compared to the transmission of the terminal 200, or the transmission status of the terminal 200.

[0085] For example, when giving priority to the transmission of the base station 100 over the terminal 200, the base station 100 may set a larger CP extension amount for the base station 100 than for the terminal 200. By setting this CP extension amount, for example, by advancing the transmission start timing of the base station 100 compared to the terminal 200, it becomes easier for the base station 100 to acquire COT, enabling transmission with a higher priority than the terminal 200.

[0086] Also, for example, at the beginning of a certain FFP, if none of the terminals 200 perform transmission (or if transmission does not start even for the terminal 200 with the shortest CP extension among the terminals 200 that can transmit in the FFP), the base station 100 may start transmission and acquire COT. Thereby, for example, it is possible to suppress the occurrence of a situation where neither any of the terminals 200 nor the base station 100 perform transmission in the FFP (in other words, a situation where the FFP is not utilized), and improve the transmission efficiency of the unlicensed frequency band.

[0087] In this way, the base station 100 may determine a coordinated CP extension amount (for example, a CP extension amount for multiple transmission timings) between the terminal 200 and the base station 100. Also, the terminal 200 may control uplink transmission based on, for example, the CP extension setting information (for example, the CP extension amount for multiple transmission timings) notified from the base station 100.

[0088] For example, by setting the CP extension amount to prioritize the COT acquisition of the terminal 200 or the base station 100, the terminal 200 (or the base station 100) with a higher priority can more easily acquire the COT, so that the transmission delay can be reduced. For example, the base station 100 can set a higher priority for the transmission of the base station 100 than the transmission of the terminal 200 by setting the CP extension amount. Therefore, the base station 100 can dynamically perform COT acquisition and downlink transmission based on, for example, the priorities of the transmission of the base station 100 and the transmission of the terminal 200, so that the flexibility of scheduling can be improved.

[0089] In addition, for example, based on the transmission status of the terminal 200, when none of the terminals 200 transmit in a certain FFP, the base station 100 can determine its own transmission (in other words, acquire the COT), thereby suppressing the occurrence of a situation where the FFP is not utilized. Also, for example, even when data is generated at a timing during the FFP (in other words, a timing different from the timing at the start of the FFP) in the base station 100 and the terminal 200, transmission becomes possible, so that the transmission delay time can be reduced.

[0090] In this way, for example, even when a UE-initiated COT is performed when the COT acquisition timing is at the start of the FFP, the scheduling efficiency for the base station 100 and the terminal 200 can be improved. Therefore, according to the present embodiment, the transmission efficiency can be improved when UE-initiated COT scheduling is performed in an unlicensed frequency band.

[0091] Note that a plurality of CP extension amounts may be set for one terminal 200. For example, different CP extension amounts may be set between FFP (for example, the CP extension amount is periodically changed). By setting this CP extension amount, for example, in a certain FFP, a larger CP extension amount may be set, and in other FFP, a smaller CP extension amount may be set. In this way, since the priority of COT acquisition for each terminal 200 is different between FFP, the fairness of the priority for COT acquisition between a plurality of terminals 200 can be improved. Also, for example, a plurality of candidates for the CP extension amount may be set for one terminal 200 in the same FFP, and an operation of selecting (for example, randomly selecting) from among the plurality of candidates may be performed. By this operation, for example, the priority of COT acquisition in one terminal 200 can be changed, and the fairness of the priority for COT acquisition between terminals 200 can be improved.

[0092] In addition, the base station 100 may perform prioritization for COT acquisition between terminals 200 (or between the terminal 200 and the base station 100) by setting the transmission timing of data, for example, not limited to the setting of the CP extension amount. For example, the base station 100 may set the transmission timing of the data to be set for the terminal 200 or the base station 100 with a higher priority earlier. For example, the base station 100 may set the transmission timing of the terminal 200 with a higher priority one symbol earlier than that of other terminals 200. By this setting, the terminal 200 or the base station with a higher priority can perform transmission with a higher priority than other terminals.

[0093] (Embodiment 2) The configuration example of the base station and the terminal according to this embodiment may be the same as that of Embodiment 1 for other functions, for example, except that some functions are different from those of Embodiment 1.

[0094] As described above, for example, the CP extension in DG-PUSCH is the CP extension for gap adjustment used for adjusting the gap length. Also, for example, the control method of Embodiment 1 (e.g., the method of controlling the transmission priority of the terminal 200 or the base station 100 by setting a plurality of transmission start timings at the head of the FFP) may be applied to DG-PUSCH. In other words, multiple transmission timing CP extensions may be supported for DG-PUSCH.

[0095] However, when transmitting PUSCH within the COT of the base station 100 (e.g., gNB COT), the CP extension for gap adjustment may be supported.

[0096] Therefore, in this embodiment, for example, a method of setting both the multiple transmission timing CP extension and the CP extension for gap adjustment for DG-PUSCH will be described. Note that in this embodiment, PUSCH is not limited to DG-PUSCH and may also be CG-PUSCH.

[0097] In the base station 100 (Fig. 6), when determining the CP extension setting information (e.g., CP extension amount) for each terminal 200, for example, the scheduling unit 104 may separately set the CP extension setting information to be applied within the COT (e.g., gNB COT) acquired by the base station 100 and the CP extension setting information to be applied during a period different from the COT of the base station 100 (e.g., the head of the FFP). The scheduling unit 104 outputs the determined CP extension setting information to the control information holding unit 105, for example. Also, the scheduling unit 104 may perform signaling information transmission and scheduling of PUSCH transmission of the terminal 200 using the CP extension setting information, for example.

[0098] In the terminal 200 (Fig. 7), the transmission control unit 204 may determine whether the PUSCH to be transmitted is within the COT (e.g., gNB COT) of the base station 100 based on, for example, control information such as Configured grant setting information and FBE setting information input from the control information holding unit 205, or the decoding result input from the demodulation / decoding unit 202. The transmission control unit 204 may determine the amount of CP extension to be applied to the PUSCH based on the determination result and the CP extension setting information, and output information regarding the determined amount of CP extension to the CP addition unit 208.

[0099] [Operation examples of base station 100 and terminal 200] An operation example in the base station 100 and terminal 200 having the above configuration will be described.

[0100] In the present embodiment, for example, the combination of a plurality of candidate CP extension amounts (e.g., candidate CP lengths) that can be notified by the CP extension setting information may be different for each type of COT. For example, the base station 100 may include any one of a plurality of combinations of different candidate CP lengths for each type of COT in the control information. Further, the terminal 200 may determine one CP extension amount from among the plurality of candidate CP lengths of the combination corresponding to the type of COT based on, for example, the control information notified from the base station 100.

[0101] The type of COT may include, for example, gNB COT and a period different from gNB COT.

[0102] For example, examples of the COT acquisition control method in the case where the PUSCH transmitted by the terminal 200 is "DG-PUSCH", the case of "type 1 CG PUSCH", and the case of "type 2 CG PUSCH" will be described. The terminal 200 may perform COT acquisition and PUSCH transmission based on, for example, control information from the base station 100.

[0103] [Case of DG-PUSCH] For example, two types of tables may be set: a table for setting the CP extension amount applied within the COT (gNB COT) of the base station 100 (for example, an example of the association between an index and the CP extension amount for gap adjustment), and a table for setting the CP extension amount applied during a period different from the COT of the base station 100 (for example, an example of the association between an index and the CP extension amount for multiple transmission timings).

[0104] The table applied within the gNB COT (for example, referred to as "Table 1") may be used, for example, for notifying the CP extension for gap adjustment. Also, the table applied during a period different from the gNB COT (for example, referred to as "Table 2") may be used, for example, for notifying the CP extension for multiple transmission timings.

[0105] For example, Table 1 may or may not include other parameters such as channel access type and CAPC in addition to the CP extension amount for gap adjustment. Also, for example, Table 2 may or may not include parameters different from the CP extension amount for multiple transmission timings. For example, in Table 2, the size of the table can be reduced by reducing the candidate settings of the parameters.

[0106] Also, for example, a common index may be set in Table 1 and Table 2. In other words, the base station 100 and the terminal 200 may determine the table to be applied (or referred to) in COT acquisition and PUSCH transmission from among Table 1 and Table 2 according to the type of COT (or transmission timing).

[0107] For example, the terminal 200 may determine the table to be referred to based on whether the timing of transmitting PUSCH is within the COT (gNB COT) of the base station 100. The terminal 200 may determine whether it is the gNB COT, for example, based on the FBE configuration information and the COT information (e.g., COT duration) included in the downlink control information (e.g., DCI format 2_0). For example, when the terminal 200 is instructed to transmit at the beginning of the FFP based on the FBE configuration information, for example, it may determine that it is a period different from the gNB COT and select Table 2. Also, for example, the terminal 200 may determine the duration of the COT based on the COT information, and if the timing of being instructed to transmit is within the duration of the COT, it may determine that it is within the gNB COT and select Table 1.

[0108] The index to be referred to in the table may be notified from the base station 100 to the terminal 200, for example. The index may be notified to the terminal 200 using, for example, the UL grant. For example, the terminal 200 may set any one of a plurality of candidate CP extension amounts in the selected table according to the index included in the control information (e.g., CP extension configuration information) notified from the base station 100.

[0109] FIG. 10 is a diagram showing an example of Table 1 and Table 2 for setting the CP extension.

[0110] Table 1 shown in FIG. 10 is, for example, a table applied within the COT of the base station 100, and the CP extension for gap adjustment may be set. In the example shown in FIG. 10, although the CP extension amount is included in Table 1, it is not limited thereto. For example, an index of another table (e.g., the index of Table 5.3.1-1 in Non-Patent Document 1) that defines the CP extension amount for gap adjustment may be included.

[0111] Also, in Table 1 shown in FIG. 10, for example, in addition to the CP extension amount, Channel Access Type and CAPC may be included. As an example, the CP extension amount may be set (e.g., joint encoding) together with Channel Access Type and CAPC in DCI format 0_1. Note that Table 1 may not include at least one of Channel Access Type and CAPC, and may include other parameters.

[0112] Table 2 shown in FIG. 10 is a table applied during a period different from the COT of base station 100, and a CP extension for multiple transmission timings may be set. Note that in the example shown in FIG. 10, Table 2 includes a CP extension amount, but is not limited thereto. For example, an index of another table that defines the CP extension amount for multiple transmission timings (e.g., the index of Table 5.3.1-2 in Non-Patent Document 1) may be included.

[0113] Also, in Table 2 shown in FIG. 10, for example, in addition to the CP extension amount, CAPC may be included. As an example, the CP extension amount may be set (e.g., joint encoding) together with CAPC. Note that Table 2 may not include CAPC, and may include other parameters.

[0114] For example, at least one candidate CP extension amount included in Table 1 (e.g., combination of candidate CPs) corresponding to the COT of base station 100 (e.g., the first type) may be based on Timing alignment (TA) and Channel Access Type (or category of LBT). On the other hand, the candidate CP extension amount length included in Table 2 corresponding to a period different from the COT of base station 100 (e.g., the second type) may not be based on TA and Channel Access Type. Also, for example, the granularity of the CP extension amount included in Table 2 may be finer than the granularity of the CP extension amount included in Table 1.

[0115] In this way, for DG-PUSCH, in addition to the CP extension for gap adjustment, multiple transmission timing CP extensions can be set. Thereby, for example, in COT acquisition at the FFP start (e.g., a period different from the gNB COT), base station 100 can set the transmissions of both CG-PUSCH and DG-PUSCH (e.g., multiple transmission timing CP extensions), so the degree of freedom in scheduling at base station 100 can be improved.

[0116] Also, for example, even when CG-PUSCH and DG-PUSCH are mixed, base station 100 may set priorities (e.g., different CP extension amounts) for CG-PUSCH and DG-PUSCH and perform scheduling. Thereby, base station 100 can prioritize PUSCH transmissions with shorter delay settings regardless of, for example, CG-PUSCH and DG-PUSCH, so the delay time can be reduced.

[0117] Also, for example, regarding the setting of the CP extension amount for gap adjustment CP extension and CP extension for multiple transmission timings, as shown in FIG. 10, when using two tables compared to using one table, the size of each table (in other words, the number of indexes) can be reduced, so the signaling overhead when notifying the index can be reduced.

[0118] Note that, for example, it is not limited to two tables according to the COT type as shown in FIG. 10, and a setting in which the CP extension amount for gap adjustment and the CP extension amount for multiple transmission timings are mixed in one table may be used. In this case, for example, when referring to the index of another table that defines the CP extension amount, it may be explicitly set (or defined) which CP extension (in other words, which other table) it is. FIG. 11 is a diagram showing an example including the CP extension amount for gap adjustment and the CP extension amount for multiple transmission timings in one table. In FIG. 11, for example, indexes in a plurality of tables (for example, Table 1 and Table 2) may be set.

[0119] Also, for example, the tables (or combinations of CP extensions for multiple transmission timings) applied in periods different from the gNB COT are not limited to one, and a plurality of them may be set. For example, the granularity of the CP extension amount for multiple transmission timings in each of the plurality of tables applied in periods different from the gNB COT may be different.

[0120] <In the case of type 1 CG PUSCH> In type 1 CG, for example, the CP extension applied within the COT of base station 100 (e.g., gNB COT), such as the CP extension for gap adjustment, and the CP extension applied during a period different from the COT of base station 100 (e.g., CP extension for multiple transmission timings) may be set semi-statically and individually for terminal 200.

[0121] Terminal 200 may determine the CP extension to be applied to type 1 CG PUSCH, for example, based on whether it is within the COT of base station 100.

[0122] In this way, different types of CP extensions can be set for type 1 CG-PUSCH. Thereby, for example, base station 100 can switch and use different CP extensions inside and outside the gNB COT in type 1 CG, so that the freedom of scheduling in base station 100 can be improved.

[0123] Note that when CG transmission is performed during a period different from the COT of base station 100 (for example, at the beginning of FFP), in other words, when CG transmission is not performed within the COT of base station 100, if the CP extension is not used separately, one type of CP extension amount may be set.

[0124] <In the case of type 2 CG PUSCH> In type 2 CG, for example, since activation is performed by PDCCH (or DCI), a method using two tables corresponding to the COT type (e.g., Figure 10), similar to DG-PUSCH, may be applied.

[0125] For example, a table to be applied within the COT of base station 100 (e.g., table 1 shown in Figure 10) and a table to be applied during a period different from the COT of base station 100 (e.g., table 2 shown in Figure 10) may be set.

[0126] The terminal 200 may determine the table to be referred to based on, for example, whether the timing of transmitting the CG-PUSCH is within the COT (gNB COT) of the base station 100. Also, the index corresponding to the table determined by the terminal 200 may be set (or notified) to the terminal 200 by, for example, the activation PDCCH. Further, for example, the index set for the terminal 200 may be used until the transmission of the CG-PUSCH is stopped by de-activation or until it is re-activated.

[0127] In this way, different types of CP extensions can be set for type 2 CG-PUSCH. Thereby, for example, the base station 100 can switch and use the CP extension inside and outside the gNB COT in type 2 CG. Also, the base station 100 can dynamically set the amount of CP extension for each terminal 200 by, for example, the activation PDCCH. Therefore, the degree of freedom in scheduling at the base station 100 for type 2 CG-PUSCH can be improved.

[0128] Note that in Type 2 CG, similar to type 1 CG, different types of CP extensions may be set semi-statically. Also, for example, when CG transmission is performed during a period different from the COT of the base station 100 (for example, at the beginning of the FFP) (in other words, when CG transmission is not performed in the COT of the base station 100), if the CP extension is not used properly, one type of CP extension amount may be set.

[0129] The example of the COT acquisition control method has been described above.

[0130] As described above, in this embodiment, combinations (e.g., tables) of a plurality of candidate CP extension amounts with respect to the CP extension amount notified by the CP extension setting information may differ for each type of COT. The base station 100 can control, for example, the CP extensions for multiple transmission timings for both the DG-PUSCH and the CG-PUSCH. Thereby, the base station 100 can reduce the delay of PUSCH transmission in the terminal 200 by setting the CP extension amount according to the type of each PUSCH transmission (e.g., service type or delay requirement) for both the DG-PUSCH and the CG-PUSCH.

[0131] Note that, as the method for controlling COT acquisition in this embodiment, the method for controlling COT acquisition in Embodiment 1 (e.g., the method of controlling the transmission priority of the terminal 200 or the base station 100 by setting a plurality of transmission start timings at the head of the FFP) may be applied, or other control methods may be applied.

[0132] (Embodiment 3) The configuration example of the base station and the terminal according to this embodiment may be different in some functions from Embodiment 1, and other functions may be the same as those in Embodiment 1.

[0133] [Time-domain Scheduling] When performing time-domain scheduling in the DG-PUSCH, the transmission timing of the PUSCH starting from the timing when the UL grant is received may be indicated to the terminal 200.

[0134] For example, compared with the scheduling within the FFP, when the DG-PUSCH at the head of the next FFP is indicated (or scheduled) to the terminal, it may result in a more temporally distant scheduling. For example, the period of the FFP may be at most 10 ms.

[0135] To cover temporally separated scheduling, for example, there are methods such as increasing the number of bits of parameters for scheduling in the time domain (for example, the field of Time domain resource assignment (TDRA) in the UL grant), or methods of reducing the degree of freedom of scheduling. Methods of reducing the degree of freedom of scheduling include, for example, a method of increasing candidates for temporally distant scheduling instead of reducing candidates for temporally closer scheduling.

[0136] [Operation when COT acquisition fails] In the terminal 200, for example, for DG-PUSCH transmission, even if an attempt is made to acquire COT at the head of the FFP, there is a possibility that the COT cannot be acquired due to interference or the like. As described above, in FBE, since the COT is not acquired at a timing different from the head of the FFP, when the terminal 200 fails to acquire the COT at the head of the FFP, it waits for rescheduling from the base station 100 until at least the next FFP, so the delay time may increase.

[0137] Therefore, in the present embodiment, for example, a method of suppressing an increase in the delay time in PUSCH transmission will be described.

[0138] In the base station 100 (FIG. 6), the scheduling unit 104 may set COT acquisition setting information, for example, when determining CP extension setting information (for example, the amount of CP extension) for each terminal 200.

[0139] The COT acquisition setting information may include, for example, information related to scheduling in the time domain (for example, information different from the amount of CP extension). The information related to scheduling in the time domain may include at least one of, for example, information indicating the start timing of scheduling for the terminal 200 (corresponding to "Next FFP" described later), and information indicating candidate timings of COT for the terminal 200 (or re-attempt timings of COT acquisition) (corresponding to "Re-attempt" described later).

[0140] The scheduling unit 104 outputs, for example, the determined CP extension setting information and COT acquisition setting information to the control information holding unit 105. Further, the scheduling unit 104 may perform scheduling of the transmission of signaling information and the PUSCH transmission of the terminal 200, for example, using the CP extension setting information and the COT acquisition setting information.

[0141] In the terminal 200 (FIG. 7), the transmission control unit 204 determines, for example, the transmission timing of the PUSCH based on control information such as Configured grant setting information and FBE setting information input from the control information holding unit 205, or downlink control information (for example, CP extension setting information) and COT acquisition setting information input from the demodulation and decoding unit 202, and may instruct the data / control information generation unit 206 to generate data or control information.

[0142] [Operation examples of the base station 100 and the terminal 200] Operation examples of the base station 100 and the terminal 200 having the above configuration will be described.

[0143] For example, an example of a COT acquisition control method in the base station 100 (for example, the scheduling unit 104) will be described. The terminal 200 (for example, the transmission control unit 204) may control COT acquisition and uplink transmission (for example, PUSCH transmission) based on the control by the base station 100, for example.

[0144] <Control method 1> In Control method 1, for example, as an example of the COT acquisition setting information, signaling for notifying information (for example, "Next FFP") indicating the start timing of time domain scheduling for the terminal 200 may be added.

[0145] For example, in the time domain scheduling of DG-PUSCH, the timing at which the UL grant is received can be the starting point. On the other hand, in Control Method 1, for example, when "Next FFP" is notified to the terminal 200, the base station 100 may perform time domain scheduling of DG-PUSCH starting from the beginning of the FFP corresponding to Next FFP (for example, the FFP after the timing at which the UL grant is received).

[0146] For example, the FFP corresponding to Next FFP may be the FFP next to the current FFP. Note that the current FFP is, for example, the FFP at the timing of receiving the UL grant, and the next FFP may be the FFP in the next cycle with respect to the current FFP.

[0147] Hereinafter, an example of notifying Next FFP will be described. Example 1: For example, "Next FFP" may be notified to the terminal 200 by a 1-bit flag.

[0148] For example, the starting point of time domain scheduling may be set for the terminal 200 by a 1-bit flag corresponding to Next FFP. As an example, Next FFP = "0" may mean starting from the UL grant, and Next FFP = "1" may mean starting from the beginning of the FFP next to the timing of receiving the UL grant.

[0149] Next FFP (1-bit flag) may be notified (joint encoding) to the terminal 200 together with, for example, the CP extension amount (for example, CP extension setting information), or may be notified to the terminal 200 individually in the field of the UL grant.

[0150] FIG. 12 shows, as an example, an example in which Next FFP is notified together with the CP extension amount (and CAPC). For example, the table shown in FIG. 12 (for example, an example of the association between an index, the CP extension amount, CAPC, and Next FFP) may be preset from the base station 100 to the terminal 200. Note that the table shown in FIG. 12 is an example, and for example, the parameters included in the table may not include CAPC, or may include other parameters different from CAPC.

[0151] In this way, by notifying the "Next FFP" to the terminal 200, the base station 100 can schedule, for example, starting from the next FFP start of the FFP at the timing when the UL grant is received. The parameters for time domain scheduling for the terminal 200 (for example, TDRA) may be the same as the parameters starting from the timing when the UL grant is received. Therefore, the signaling overhead of the parameters for time domain scheduling (for example, TDRA) can be reduced, and the degree of freedom of scheduling in the time domain can be improved.

[0152] Note that the start point of time domain scheduling notified to the terminal 200 by Next FFP is not limited to the next FFP of the FFP that received the UL grant, and may be any FFP after the FFP that received the UL grant.

[0153] Example 2: For example, "Next FFP" may be notified to the terminal 200 by an M-bit field.

[0154] For example, a time-domain scheduling start point may be set for the terminal 200 by an M-bit field corresponding to Next FFP. For example, Next FFP may notify how many FFP ahead from the timing of receiving the UL grant is set as the start point of time-domain scheduling. For example, Next FFP = "0" may mean starting from the UL grant, and Next FFP = "m" may mean starting from the head of the FFP m times ahead from the timing of receiving the UL grant. Note that m may represent a value notified in an M-bit field, for example.

[0155] Next FFP (for example, an M-bit field) may be notified jointly with, for example, the CP extension amount (for example, CP extension setting information), or may be notified individually in the UL grant field. For example, when Next FFP is notified jointly with the CP extension amount, for example, similar to Example 1, the table shown in FIG. 12 may be preset from the base station 100 to the terminal 200.

[0156] In this way, by notifying the "Next FFP" to the terminal 200 in the M-bit field, for example, the base station 100 can perform scheduling starting from the head of a more advanced FFP or more FFPs compared to Example 1. Also, the parameters for time-domain scheduling for the terminal 200 (for example, TDRA) may be the same as the parameters starting from the timing of receiving the UL grant. Therefore, the signaling overhead of the parameters for time-domain scheduling (for example, TDRA) can be reduced, and the degree of freedom of scheduling can be improved.

[0157] <Control Method 2> In Control Method 2, for example, as an example of the COT acquisition setting information, signaling for notifying information indicating re-attempt of COT acquisition (for example, "Re-attempt") when the terminal 200 fails to acquire COT may be added.

[0158] For example, when the terminal 200 is instructed to re-attempt and fails to obtain the COT in the scheduled FFP, it may re-attempt to obtain the COT in the FFP corresponding to "Re-attempt".

[0159] For example, the FFP corresponding to Re-attempt may be the next FFP of the current FFP. Note that the current FFP is, for example, the FFP at the timing of receiving the UL grant, and the next FFP may be the FFP of the next cycle with respect to the current FFP.

[0160] Hereinafter, an example of notification of Re-attempt will be described.

[0161] Example 1: For example, re-attempt of COT acquisition may be notified to the terminal 200 by a 1-bit flag.

[0162] For example, the terminal 200 may be instructed whether to re-attempt COT acquisition when COT acquisition fails by a 1-bit flag corresponding to Re-attempt. As an example, Re-attempt = "0" may mean not to re-attempt even if COT acquisition fails, and Re-attempt = "1" may mean to re-attempt COT acquisition in the next FFP when COT acquisition fails.

[0163] Also, for example, when COT acquisition fails during re-attempt in the next FFP, whether to further re-attempt COT acquisition or the number of re-attempts may be preset or defined. For example, the number of re-attempts may be once or multiple times.

[0164] Also, the CP extension amount may be changed during the re - attempt to obtain COT. For example, during the re - attempt, by increasing the CP extension amount, the transmission priority for terminal 200 may be set higher. By increasing the priority, the possibility of obtaining COT can be increased, thus reducing the delay time. Or, for example, during the re - attempt, by decreasing the CP extension amount, the transmission priority for terminal 200 may be set lower. By decreasing the priority, for example, among multiple terminals 200 (or base stations), the directly scheduled transmission may be prioritized over the re - attempted transmission by Re - attempt. Note that the change in the CP extension amount during the re - attempt may be preset or defined in advance.

[0165] Re - attempt (a 1 - bit flag) may be notified (joint encoding) to terminal 200 together with, for example, the CP extension amount (e.g., CP extension setting information), or may be individually notified to terminal 200 in the field of UL grant.

[0166] FIG. 13 shows, as an example, an example in which Re - attempt is notified together with the CP extension amount (and CAPC). For example, the table shown in FIG. 13 (e.g., the association between the index, CP extension amount, CAPC, and Re - attempt) may be preset from base station 100 to terminal 200. Note that the table shown in FIG. 13 is just an example, and for example, the parameters included in the table may not include CAPC, or may include other parameters different from CAPC.

[0167] In this way, by notifying terminal 200 of the instruction (Re - attempt) regarding the re - attempt to obtain COT, even if terminal 200 fails to obtain COT of the FFP scheduled by base station 100, for example, through the re - attempt to obtain COT in the next FFP, there is a possibility that terminal 200 can perform uplink transmission without waiting for the scheduling from base station 100, thus reducing the delay time.

[0168] Note that the re - attempt timing of COT acquisition notified to the terminal 200 by Re - attempt is not limited to the next FFP after the FFP that received the UL grant, and may be any FFP after the FFP that received the UL grant.

[0169] Example 2: For example, an instruction regarding re - attempt of COT acquisition (e.g., Re - attempt) may be notified to the terminal 200 by an M - bit field.

[0170] For example, the conditions for re - attempting COT acquisition when COT acquisition fails may be instructed to the terminal 200 by an M - bit field corresponding to Re - attempt.

[0171] For example, the number of re - attempts may be instructed to the terminal 200 by an M - bit field. With the instruction of the number of re - attempts, the base station 100 can dynamically set (e.g., change) the number of re - attempts based on, for example, the state of the terminal 200 in the cell (e.g., the presence or absence of a terminal 200 having high - priority data), thereby realizing reduction of delay time and improvement of scheduling freedom.

[0172] Also, for example, the conditions for re - attempt such as "re - attempt if it is a UL symbol" or "re - attempt if it is either a UL symbol or a Flexible symbol" may be instructed (or specified) to the terminal 200 by an M bit field. With the instruction of the conditions for re - attempt, the base station 100 can, for example, instruct the terminal 200 to re - attempt COT acquisition at a timing that satisfies the conditions (e.g., the type of symbol), so that the scheduling freedom of the base station 100 can be improved.

[0173] Also, for example, an M-bit field may also notify the setting (e.g., increase or decrease) of the CP extension amount during re-attempt. Thereby, for example, the CP extension amount in the attempt to obtain COT (including re-attempt) can be dynamically set, so that the reduction of the delay time and the improvement of the scheduling freedom of the base station 100 can be realized.

[0174] Also, Re-attempt (M-bit field) may be notified (joint encoding) to the terminal 200 together with, for example, the CP extension amount (e.g., CP extension setting information), and may be individually notified to the terminal 200 in the field of the UL grant. For example, when Re-attempt is notified together with the CP extension amount, for example, similar to Example 1, the table shown in FIG. 13 may be preset from the base station 100 to the terminal 200.

[0175] In this way, when "Re-attempt" is notified to the terminal 200 in the M-bit field, the re-attempt of COT acquisition can be conditionally instructed. Therefore, in addition to the effects of Example 1, the scheduling freedom of the base station 100 can be improved.

[0176] The control method 1 and the control method 2 have been described above.

[0177] Note that the control method 1 and the control method 2 may be applied in combination. For example, when the terminal 200 fails to obtain COT in the FFP transmitted by "Next FFP", it can be instructed by "Re-attempt" whether to re-attempt to obtain COT in the next FFP. Thereby, the reduction of the delay time and the improvement of the scheduling freedom can be achieved.

[0178] Note that, as the method for controlling COT acquisition in the present embodiment, the method for controlling COT acquisition in Embodiment 1 (for example, the method for controlling the transmission priority of the terminal 200 or the base station 100 by setting a plurality of transmission start timings at the head of the FFP) may be applied, or other control methods may be applied.

[0179] (Embodiment 4) [Priority setting in Release 16 URLLC] As an extension to the Release 16 URLLC function, a function for defining or setting the priority for terminal transmission by "priority (High or Low)" is supported. This function may be used to determine (or judge) the prioritized transmission when a plurality of transmissions are triggered in the terminal. For example, the priority of the PUSCH may be set dynamically by the UL grant or semi-statically.

[0180] In the present embodiment, for example, a method for controlling the CP extension setting based on the priority of terminal transmission (or data, channel, or service type) will be described.

[0181] The configuration examples of the base station and the terminal according to the present embodiment may be the same as those in Embodiment 1 for some functions, for example, while being different from those in Embodiment 1 for other functions.

[0182] In the base station 100 (Fig. 6), when determining the CP extension setting information (for example, the CP extension amount) for each terminal 200, the scheduling unit 104 may set a plurality of CP extension setting information corresponding to a plurality of priorities respectively. The scheduling unit 104 may output the determined CP extension setting information to the control information holding unit 105, for example. Further, the scheduling unit 104 may perform signaling information transmission and PUSCH transmission scheduling of the terminal 200 using these CP extension setting information, for example.

[0183] In the terminal 200 (Fig. 7), the transmission control unit 204 may refer to the CP extension setting information corresponding to the priority of the PUSCH to be transmitted based on, for example, the Configured grant setting information input from the control information holding unit 205 or the decoding result input from the demodulation and decoding unit 202, and determine the amount of CP extension to be applied to the PUSCH. For example, the transmission control unit 204 outputs information regarding the determined amount of CP extension to the CP addition unit 208.

[0184] [Operation examples of the base station 100 and the terminal 200] The operation examples in the base station 100 and the terminal 200 having the above configuration will be described.

[0185] In the present embodiment, for example, the combinations of a plurality of candidate CP extension amounts (e.g., candidate CP lengths) that can be notified by the CP extension setting information may be different for each priority (priority level) of the transmission of the terminal 200.

[0186] For example, the base station 100 may include any one of a plurality of combinations of different candidate CP lengths for each priority of the transmission of the terminal 200 in the control information. Further, the terminal 200 may determine one CP extension amount from among the plurality of candidate CP lengths in the combination corresponding to the priority of the transmission of the terminal 200 based on, for example, the control information notified from the base station 100.

[0187] The priority of the transmission of the terminal 200 may include, for example, "high" and "low". Note that the priority of the transmission of the terminal 200 is not limited to two types and may be three or more types.

[0188] For example, examples of the COT acquisition control method in the case where the PUSCH transmitted by the terminal 200 is "DG-PUSCH", the case of "type 1 CG PUSCH", and the case of "type 2 CG PUSCH" will be described. The terminal 200 may perform COT acquisition and PUSCH transmission based on, for example, the control information from the base station 100.

[0189] <In the case of DG-PUSCH> For example, a table for notifying a plurality of CP extension amounts based on priority may be set. The table for notifying the CP extension amount based on priority may be set by the base station 100 in advance for the terminal 200, or may be defined in the standard.

[0190] Here, for high-priority transmissions, it is assumed that, for example, a larger CP extension amount is set to facilitate obtaining the COT. Therefore, for example, the table corresponding to a high priority may be set to include candidates with a larger CP extension amount compared to the table corresponding to a low priority.

[0191] For example, the terminal 200 may determine the table to be referred to during PUSCH transmission based on the priority notified by the UL grant. Also, the terminal 200 may implicitly determine the table to be referred to during PUSCH transmission based on other parameters that can determine the priority even when there is no priority notification. Other parameters that can determine the priority include, for example, the DCI format or an identifier used by the terminal 200 (e.g., Radio Network Temporary Identifier (RNTI)).

[0192] For example, when there are two types of priorities, high and low, two types of tables for setting the CP extension amount may be set. The terminal 200 may determine the table to be referred to during PUSCH transmission based on the notification of the UL grant (e.g., priority) instructing PUSCH transmission.

[0193] FIG. 14 is a diagram showing an example of a table (for example, an example of an association between an index and a CP extension amount) that sets CP extension amounts corresponding to each of low priority and high priority.

[0194] The high-priority table shown in FIG. 14 may include, for example, a larger CP extension amount (for example, "T-16us", "T-25us", or "T-341us") compared to the CP extension amount of the low-priority table (for example, "T-43us", "T-52us", or "T-61us").

[0195] Note that the CP extension amounts included in the high-priority table and the low-priority table are not limited to the example shown in FIG. 14, and in the high-priority table and the low-priority table, some CP extension amounts may be included in duplicate. Also, the table shown in FIG. 14 includes, for example, Channel Access Type and CAPC in addition to the CP extension amount, but is not limited thereto. For example, at least one of Channel Access Type and CAPC may not be included, and other parameters may be included.

[0196] In this way, for DG-PUSCH, by setting or defining a plurality of tables corresponding to the transmission priority of the terminal 200 and switching the table referred to by the terminal 200 according to the priority, the terminal 200 can transmit PUSCH (for example, obtain COT) with a CP extension amount corresponding to the priority of the DG-PUSCH transmission.

[0197] Also, for example, compared with the case where the CP extension amounts corresponding to a plurality of priorities are set in one table, since the CP extension amounts are set in a plurality of tables corresponding to a plurality of priorities, the number of candidates for the CP extension amount (in other words, the number of indexes) included in each table can be reduced, and the signaling overhead for notifying the indexes can be reduced.

[0198] <In the case of type 1 CG-PUSCH> In type 1 CG, the transmission priority of the terminal 200 may be set semi-statically, for example. Also, for example, the priorities of the upper layer data included in the physical layer data (e.g., the priorities of the logical channels) may dynamically vary.

[0199] Therefore, for example, a plurality of tables corresponding to the priorities of the logical channels may be set for the CP extension amount. The terminal 200 may determine the table to be referred to based on any of the priorities of the upper layer data included in the physical layer data, for example. For example, the terminal 200 may dynamically switch the CP extension by determining the table to be referred to based on the most prioritized logical channel. Note that the determination of the table reference is not limited to the highest priority and may be other priorities.

[0200] In this way, for type 1 CG-PUSCH, by switching the CP extension according to the priority of the logical channel, it becomes possible to support dynamic control of the priority even in type 1 CG operating by semi-static setting, and the delay time of the data to be transmitted with higher priority can be reduced.

[0201] <In the case of type 2 CG-PUSCH> In type 2 CG, for example, the priority may be set for each activation using the priority field included in the activation PDCCH.

[0202] Therefore, for example, similar to DG-PUSCH, multiple tables corresponding to multiple priorities may be set for the CP extension amount.

[0203] The terminal 200 may determine, for example, the table to be referred to during CG-PUSCH transmission and the CP extension amount corresponding to the notified index in the table based on the priority and the table index notified by the activation PDCCH.

[0204] In this way, for type 2 CG-PUSCH, the terminal 200 can flexibly set the CP extension amount (for each activation or re-activation) by determining the CP extension amount based on the priority and index notified by the activation PDCCH, as compared with the case of semi-statically determining the CP extension.

[0205] Also, for example, compared with the case where the CP extension amounts corresponding to multiple priorities are set in one table, since the CP extension amounts are set in multiple tables corresponding to multiple priorities, the number of candidates for the CP extension amount (in other words, the number of indexes) included in each table can be reduced, and the signaling overhead for notifying the index can be reduced.

[0206] The example of the COT acquisition control method has been described above.

[0207] As described above, in this embodiment, combinations (e.g., tables) of a plurality of candidate CP extension amounts with respect to the CP extension amount notified by the CP extension setting information may differ for each transmission priority of the terminal 200. The base station 100 can reduce the delay of PUSCH transmission in the terminal 200, for example, by setting a plurality of transmission timing CP extensions for both the DG-PUSCH and the CG-PUSCH based on the PUSCH transmission priority.

[0208] Note that in this embodiment, for example, the transmission priority in the terminal 200 has been described, but it is not limited thereto, and the priority may be, for example, the priority among a plurality of terminals 200 (or the base station 100).

[0209] In addition, for the method of controlling COT acquisition in this embodiment, the method of controlling COT acquisition in Embodiment 1 (for example, the method of controlling the transmission priority of the terminal 200 or the base station 100 by setting a plurality of transmission start timings at the head of the FFP) may be applied, or other control methods may be applied.

[0210] The above describes an example of the present disclosure.

[0211] (Other Embodiments) Also, each of the above embodiments may be applied in combination.

[0212] In the above-described embodiments, the uplink signal is not limited to an uplink data channel such as PUSCH, DG-PUSCH, or CG-PUSCH, and may be other signals or channels. For example, it may be applied to a Physical Uplink Control Channel (PUCCH) or a Sounding Reference Signal (SRS). For example, since PUCCH or SRS may be instructed to be transmitted by a DL assignment (e.g., dynamic downlink data scheduling information) instead of a UL grant, the UL grant in the above-described embodiments may be replaced with a DL assignment and applied.

[0213] (Control signal) In an embodiment of the present disclosure, the downlink control signal (or downlink control information) may be, for example, a signal (or information) transmitted in a Physical Downlink Control Channel (PDCCH) of the physical layer, or a signal (or information) transmitted in a Medium Access Control (MAC) or Radio Resource Control (RRC) of a higher layer. Further, the signal (or information) is not limited to the case notified by the downlink control signal, and may be predefined in a specification (or standard), or may be preset in a base station and a terminal.

[0214] In an embodiment of the present disclosure, the uplink control signal (or uplink control information) may be, for example, a signal (or information) transmitted in a PDCCH of the physical layer, or a signal (or information) transmitted in a MAC or RRC of a higher layer. Further, the signal (or information) is not limited to the case notified by the uplink control signal, and may be predefined in a specification (or standard), or may be preset in a base station and a terminal. Further, the uplink control signal may be replaced with, for example, uplink control information (UCI), 1st stage sidelink control information (SCI), or 2nd stage SCI.

[0215] (Base station) In one embodiment of the present disclosure, the base station may be a Transmission Reception Point (TRP), a cluster head, an access point, a Remote Radio Head (RRH), an eNodeB (eNB), a gNodeB (gNB), a Base Station (BS), a Base Transceiver Station (BTS), a master unit, a gateway, or the like. Also, in sidelink communication, it may be a terminal instead of the base station. Further, instead of the base station, it may be a relay device that relays communication between a higher node and a terminal.

[0216] (Uplink / Downlink / Sidelink) One embodiment of the present disclosure may be applied to, for example, any of an uplink, a downlink, and a sidelink. For example, one embodiment of the present disclosure may be applied to a Physical Uplink Shared Channel (PUSCH), a Physical Uplink Control Channel (PUCCH), a Physical Random Access Channel (PRACH) in the uplink, a Physical Downlink Shared Channel (PDSCH), a PDCCH, a Physical Broadcast Channel (PBCH) in the downlink, or a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Broadcast Channel (PSBCH) in the sidelink.

[0217] Note that each of PDCCH, PDSCH, PUSCH, and PUCCH is an example of a downlink control channel, a downlink data channel, an uplink data channel, and an uplink control channel. Also, PSCCH and PSSCH are examples of a sidelink control channel and a sidelink data channel. Further, PBCH and PSBCH are notification (broadcast) channels, and PRACH is an example of a random access channel.

[0218] (Data Channel / Control Channel) One embodiment of the present disclosure may be applied to, for example, either a data channel or a control channel. For example, the channel in one embodiment of the present disclosure may be replaced with any one of PDSCH, PUSCH, PSSCH of the data channel, or PDCCH, PUCCH, PBCH, PSCCH, PSBCH of the control channel.

[0219] (Reference Signal) In one embodiment of the present disclosure, the reference signal is, for example, a signal known to both a base station and a mobile station, and may also be called a Reference Signal (RS) or a pilot signal. The reference signal may be any one of Demodulation Reference Signal (DMRS), Channel State Information - Reference Signal (CSI-RS), Tracking Reference Signal (TRS), Phase Tracking Reference Signal (PTRS), Cell-specific Reference Signal (CRS), or Sounding Reference Signal (SRS).

[0220] (Time Interval) In one embodiment of the present disclosure, the unit of time resource is not limited to one or a combination of a slot and a symbol. For example, it may be a time resource unit such as a frame, a superframe, a subframe, a slot, a time slot subslot, a mini-slot, or a symbol, an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier - Frequency Division Multiplexing (SC-FDMA) symbol, or other time resource units. Also, the number of symbols included in one slot is not limited to the number of symbols exemplified in the above-described embodiments, and other numbers of symbols may be used.

[0221] (Frequency band) One embodiment of the present disclosure may be applied to either a licensed band or an unlicensed band.

[0222] (Communication) One embodiment of the present disclosure may be applied to any of communication between a base station and a terminal, communication between terminals (Sidelink communication, Uu link communication), and Vehicle to Everything (V2X) communication. For example, the channel in one embodiment of the present disclosure may be replaced with any of PSCCH, PSSCH, Physical Sidelink Feedback Channel (PSFCH), PSBCH, PDCCH, PUCCH, PDSCH, PUSCH, or PBCH.

[0223] Also, one embodiment of the present disclosure may be applied to any of a terrestrial network, a satellite, or a non-terrestrial network (NTN: Non-Terrestrial Network) using a high altitude pseudo satellite (HAPS: High Altitude Pseudo Satellite). Also, one embodiment of the present disclosure may be applied to a terrestrial network with a large cell size or a very wideband transmission network where the transmission delay is large compared to the symbol length and slot length.

[0224] (Antenna port) In one embodiment of the present disclosure, an antenna port refers to a logical antenna (antenna group) composed of one or more physical antennas. For example, an antenna port does not necessarily refer to a single physical antenna, and may refer to an array antenna composed of multiple antennas. For example, it is not specified how many physical antennas an antenna port is composed of, and it may be defined as the minimum unit capable of transmitting a reference signal by a terminal station. Also, an antenna port may be defined as the minimum unit for multiplying the weighting of a precoding vector.

[0225] <5G NR System Architecture and Protocol Stack> 3GPP continues to work towards the next release of the 5th generation mobile phone technology (also simply referred to as "5G"), including the development of a new radio access technology (NR) operating in the frequency range up to 100 GHz. The first version of the 5G standard was completed at the end of 2017, enabling the prototype production and commercial deployment of terminals (e.g., smartphones) compliant with the 5G NR standard.

[0226] For example, the system architecture as a whole assumes an NG-RAN (Next Generation - Radio Access Network) with a gNB. The gNB provides the UE-side termination of the protocols of the user plane (SDAP / PDCP / RLC / MAC / PHY) and the control plane (RRC) of the NG radio access. The gNBs are connected to each other by the Xn interface. Also, the gNB is connected to the NGC (Next Generation Core) by the Next Generation (NG) interface, more specifically, to the AMF (Access and Mobility Management Function) (for example, a specific core entity performing the AMF) by the NG-C interface, and also to the UPF (User Plane Function) (for example, a specific core entity performing the UPF) by the NG-U interface. The NG-RAN architecture is shown in FIG. 15 (see, for example, 3GPP TS 38.300 v15.6.0, section 4).

[0227] The protocol stack of the user plane of NR (see, for example, 3GPP TS 38.300, section 4.4.1) includes the PDCP (Packet Data Convergence Protocol, see section 6.4 of TS 38.300) sublayer, the RLC (Radio Link Control, see section 6.3 of TS 38.300) sublayer, and the MAC (Medium Access Control, see section 6.2 of TS 38.300) sublayer, which are terminated on the network side at the gNB. Also, a new sublayer of the access stratum (AS), the SDAP (Service Data Adaptation Protocol), is introduced above the PDCP (see, for example, section 6.5 of 3GPP TS 38.300). Also, a protocol stack for the control plane is defined for NR (see, for example, TS 38.300, section 4.4.2). An overview of the layer 2 functions is described in section 6 of TS 38.300. The functions of the PDCP sublayer, the RLC sublayer, and the MAC sublayer are listed in sections 6.4, 6.3, and 6.2 of TS 38.300, respectively. The functions of the RRC layer are listed in section 7 of TS 38.300.

[0228] For example, the Medium-Access-Control layer handles the multiplexing of logical channels and scheduling and scheduling-related functions, including handling various numerologies.

[0229] For example, the physical layer (PHY) is responsible for functions such as encoding, PHY HARQ processing, modulation, multi-antenna processing, and mapping of signals to appropriate physical time-frequency resources. Also, the physical layer handles the mapping of transport channels to physical channels. The physical layer provides services to the MAC layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used for the transmission of a specific transport channel, and each transport channel is mapped to the corresponding physical channel. For example, the physical channels include, as uplink physical channels, PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), PUCCH (Physical Uplink Control Channel), and as downlink physical channels, PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), PBCH (Physical Broadcast Channel).

[0230] The use cases / deployment scenarios of NR may include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine type communication (mMTC), which have diverse requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps in the downlink and 10 Gbps in the uplink) and effective (user-experienced) data rates about three times those provided by IMT-Advanced. On the other hand, in the case of URLLC, more stringent requirements are imposed for ultra-low latency (0.5 ms each for UL and DL in terms of user plane latency) and high reliability (1 - 10-5 within 1 ms). Finally, for mMTC, a high connection density (1,000,000 devices / km2 in urban environments), wide coverage in harsh environments, and extremely long-lived batteries (15 years) for low-cost devices may be required.

[0231] Therefore, the new numerology of OFDM (e.g., subcarrier spacing, OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) suitable for one use case may not be effective for other use cases. For example, in a low-latency service, preferably, the symbol length is shorter (and thus the subcarrier spacing is larger) and / or the number of symbols per scheduling interval (also referred to as TTI) is smaller than that of mMTC services. Further, in a deployment scenario with a large channel delay spread, preferably, the CP length is longer than that in a scenario with a short delay spread. The subcarrier spacing may be optimized according to the situation so that a similar CP overhead is maintained. The value of the subcarrier spacing supported by NR may be one or more. Correspondingly, currently, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz... are considered. The symbol length Tu and the subcarrier spacing Δf are directly related by the formula Δf = 1 / Tu. Similar to the LTE system, the term "resource element" can be used to mean the smallest resource unit composed of one subcarrier for the length of one OFDM / SC-FDMA symbol.

[0232] In the new radio system 5G-NR, for each numerology and each carrier, a resource grid of subcarriers and OFDM symbols is defined for each of the uplink and downlink. Each element of the resource grid is called a resource element and is identified based on the frequency index in the frequency domain and the symbol position in the time domain (see 3GPP TS 38.211 v15.6.0).

[0233] <Functional Separation between NG-RAN and 5GC in 5G NR> Figure 16 shows the functional separation between NG-RAN and 5GC. The logical nodes of NG-RAN are gNB or ng-eNB. 5GC has logical nodes AMF, UPF, and SMF.

[0234] For example, gNB and ng-eNB host the following main functions: - Functions of radio resource management such as radio bearer control, radio admission control, connection mobility control, and dynamic allocation (scheduling) of resources to the UE in both the uplink and downlink; - IP header compression, encryption, and integrity protection of data; - Selection of the AMF at the time of UE attachment when the routing to the AMF cannot be determined from the information provided by the UE; - Routing of user plane data towards the UPF; - Routing of control plane information towards the AMF; - Setup and release of connections; - Scheduling and transmission of paging messages; - Scheduling and transmission of system information messages (with the AMF or the operation, administration, and maintenance function (OAM) as the source); - Configuration of measurements and measurement reports for mobility and scheduling; - Transport level packet marking in the uplink; - Session management; - Support for network slicing; - Management of QoS flows and mapping to data radio bearers; - Support for UEs in the RRC_INACTIVE state; - Delivery function of NAS messages; - Sharing of the radio access network; - Dual connectivity; - Tight cooperation between NR and E-UTRA.

[0235] The Access and Mobility Management Function (AMF) hosts the following main functions: - Function to terminate Non-Access Stratum (NAS) signaling; - Security of NAS signaling; - Access Stratum (AS) security control; - Core Network (CN) node - to - node signaling for mobility between 3GPP access networks; - Reachability of idle - mode UEs (including control and execution of paging re - transmission); - Management of the registration area; - Support for in - system mobility and inter - system mobility; - Access authentication; - Access authorization including checking of roaming rights; - Mobility management control (subscription and policy); - Support for network slicing; - Selection of the Session Management Function (SMF).

[0236] Furthermore, the User Plane Function (UPF) hosts the following main functions: - Anchor point for intra - RAT mobility / inter - RAT mobility (where applicable); - External PDU (Protocol Data Unit) session point for interconnection with data networks; - Packet routing and forwarding; - Packet inspection and enforcement of policy rules for the user plane part; - Reporting of traffic usage; - Uplink classifier to support routing of traffic flows to data networks - Branching Point for supporting multi-homed PDU sessions; - QoS processing for the user plane (e.g., packet filtering, gating, UL / DL rate enforcement); - Verification of uplink traffic (mapping to the QoS flow of the SDF); - Downlink packet buffering and triggering function for downlink data notification.

[0237] Finally, the Session Management Function (SMF) hosts the following main functions: - Session management; - IP address allocation and management for the UE; - Selection and control of the UPF; - Traffic steering setting function in the User Plane Function (UPF) for routing traffic to the appropriate destination; - Enforcement of control part policies and QoS; - Notification of downlink data.

[0238] <Procedures for RRC connection setup and reconfiguration> Figure 17 shows some of the interactions between the UE, gNB, and AMF (5GC entity) in the NAS part when the UE transitions from RRC_IDLE to RRC_CONNECTED (see TS 38.300 v15.6.0).

[0239] RRC is the upper layer signaling (protocol) used for the configuration of the UE and gNB. With this transition, the AMF prepares UE context data (which includes, for example, PDU session context, security keys, UE Radio Capability, UE Security Capabilities, etc.) and sends it to the gNB together with an INITIAL CONTEXT SETUP REQUEST. Then, the gNB activates AS security with the UE. This is done by the gNB sending a SecurityModeCommand message to the UE and the UE responding to the gNB with a SecurityModeComplete message. After that, the gNB sends an RRCReconfiguration message to the UE, and upon receiving the RRCReconfigurationComplete from the UE, performs reconfiguration to set up Signaling Radio Bearer 2 (SRB2) and Data Radio Bearer (DRB). For signaling-only connections, since SRB2 and DRB are not set up, the steps related to RRCReconfiguration are skipped. Finally, the gNB notifies the AMF in an INITIAL CONTEXT SETUP RESPONSE that the setup procedure is complete.

[0240] Therefore, in the present disclosure, there is provided an entity (e.g., AMF, SMF, etc.) of a 5th Generation Core (5GC) including a control circuit that establishes a Next Generation (NG) connection with a gNodeB during operation, and a transmission unit that transmits an initial context setup message to the gNodeB via the NG connection during operation so that a signaling radio bearer between the gNodeB and a user equipment (UE) is set up. Specifically, the gNodeB transmits Radio Resource Control (RRC) signaling including a resource allocation setting information element (IE) to the UE via the signaling radio bearer. Then, the UE performs transmission on the uplink or reception on the downlink based on the resource allocation setting.

[0241] <IMT Usage Scenarios After 2020> FIG. 18 shows some of the use cases for 5G NR. In the 3rd generation partnership project new radio (3GPP NR), three use cases envisioned by IMT-2020 to support a wide variety of services and applications are being considered. The formulation of the first-phase specifications for enhanced mobile-broadband (eMBB) has been completed. Current and future work includes standardization for ultra-reliable and low-latency communications (URLLC) and massive machine-type communications (mMTC) in addition to expanding the support for eMBB. FIG. 18 shows some examples of the envisioned usage scenarios of IMT after 2020 (see, for example, ITU-R M.2083, FIG. 2).

[0242] URLLC use cases have strict requirements for performance such as throughput, latency (delay), and availability. URLLC use cases are envisioned as one of the enabling technologies to realize these future applications such as wireless control of industrial production processes or manufacturing processes, remote medical surgery, automation of power transmission and distribution in smart grids, and traffic safety. The ultra-high reliability of URLLC is supported by identifying technologies that meet the requirements set by TR 38.913. In NR URLLC in Release 15, as an important requirement, the target user plane latency is 0.5 ms in UL (uplink) and 0.5 ms in DL (downlink). The general URLLC requirement for a single packet transmission is that the block error rate (BLER) is 1E-5 for a packet size of 32 bytes when the user plane latency is 1 ms.

[0243] From the perspective of the physical layer, reliability can be improved in many possible ways. The current room for reliability improvement includes defining a separate CQI table for URLLC, a more compact DCI format, repetition of PDCCH, etc. However, this room can expand for the realization of ultra-high reliability as NR becomes more stable and more developed (regarding the important requirements of NR URLLC). Specific use cases of NR URLLC in Release 15 include extended reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0244] In addition, the technical enhancements targeted by NR URLLC aim to improve latency and reliability. Technical enhancements for latency improvement include configurable numerology, non-slot-based scheduling by flexible mapping, grant-free uplink (with preconfigured grants), slot-level repetition in the data channel, and pre-emption in the downlink. Pre-emption means that a transmission for which resources have already been allocated is stopped, and the already allocated resources are used for another transmission with lower latency / higher priority requirements requested later. Therefore, an already permitted transmission is replaced by a later transmission. Pre-emption is applicable regardless of the specific service type. For example, a transmission of service type A (URLLC) may be replaced by a transmission of service type B (such as eMBB). Technical enhancements for reliability improvement include a dedicated CQI / MCS table for a target BLER of 1E-5.

[0245] The characteristics of the use cases of mMTC (massive machine type communication) typically lie in the extremely large number of connected devices that transmit relatively small amounts of data and are typically not affected by latency. The devices are required to be low-cost and have a very long battery life. From the perspective of NR, using a very narrow bandwidth part is one solution that can save power as seen from the UE and enable a long battery life.

[0246] As described above, it is predicted that the scope of reliability improvement in NR will become broader. One of the important requirements for all cases, for example, the important requirements for URLLC and mMTC are high reliability or ultra-high reliability. Several mechanisms can improve reliability from the wireless perspective and the network perspective. Generally, there are two to three important areas that may contribute to reliability improvement. These areas include compact control channel information, repetition of data channels / control channels, and diversity regarding the frequency domain, time domain, and / or spatial domain. These areas are generally applicable to reliability improvement regardless of the specific communication scenario.

[0247] Regarding NR URLLC, further use cases with more stringent requirements, such as factory automation, transportation, and power distribution, are envisioned. The stringent requirements are high reliability (reliability up to the 10-6 level), high availability, packet size up to 256 bytes, time synchronization up to about several μs (depending on the use case, the value can be 1 μs or several μs according to the frequency range and short latency of about 0.5 ms to 1 ms, for example, 0.5 ms latency in the target user plane), and short latency of about 0.5 ms to 1 ms (for example, 0.5 ms latency in the target user plane).

[0248] Furthermore, for NR URLLC, several technical enhancements may be possible from the perspective of the physical layer. These technical enhancements include enhancements to the PDCCH (Physical Downlink Control Channel) related to compact DCI, repetition of the PDCCH, and increased monitoring of the PDCCH. Also, the enhancement of UCI (Uplink Control Information) is related to the enhancement of enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback. In addition, there may be enhancements to the PUSCH related to mini-slot level hopping, and enhancements to retransmission / repetition. The term "mini-slot" refers to a Transmission Time Interval (TTI) that contains fewer symbols than a slot (a slot has 14 symbols).

[0249] <QoS Control> The QoS (Quality of Service) model of 5G is based on QoS flows and supports both QoS flows that require a guaranteed flow bit rate (GBR: Guaranteed Bit Rate QoS flows) and QoS flows that do not require a guaranteed flow bit rate (non-GBR QoS flows). Therefore, at the NAS level, a QoS flow is the finest-grained QoS differentiation in a PDU session. A QoS flow is identified within a PDU session by a QoS Flow ID (QFI) that is carried in an encapsulation header via the NG-U interface.

[0250] For each UE, the 5GC establishes one or more PDU sessions. For each UE, the NG-RAN establishes at least one Data Radio Bearer (DRB) according to the PDU session, as shown above with reference to, for example, Figure 17. Also, additional DRBs for the QoS flows of that PDU session can be set later (it depends on the NG-RAN when to set). The NG-RAN maps packets belonging to different PDU sessions to different DRBs. While NAS-level packet filters in the UE and 5GC associate UL packets and DL packets with QoS flows, AS-level mapping rules in the UE and NG-RAN associate UL QoS flows and DL QoS flows with DRBs.

[0251] Figure 19 shows the 5G NR non-roaming reference architecture (see TS 23.501 v16.1.0, section 4.23). The Application Function (AF) (for example, an external application server hosting 5G services as illustrated in Figure 18) communicates with the 3GPP core network to provide services. For example, accessing the Network Exposure Function (NEF) or communicating with the policy framework for policy control (e.g., QoS control) (see Policy Control Function (PCF)) to support applications that affect traffic routing. Based on operator deployment, Application Functions considered trusted by the operator can communicate directly with the relevant Network Functions. Application Functions not permitted by the operator to directly access Network Functions communicate with the relevant Network Functions using the external exposure framework via the NEF.

[0252] Figure 19 further shows additional functional units of the 5G architecture, namely, Network Slice Selection Function (NSSF), Network Repository Function (NRF), Unified Data Management (UDM), Authentication Server Function (AUSF), Access and Mobility Management Function (AMF), Session Management Function (SMF), and Data Network (DN, e.g., operator services, Internet access, or third-party services). All or part of the core network functions and application services may be deployed and operate in a cloud computing environment.

[0253] Therefore, in the present disclosure, in order to establish a PDU session including a radio bearer between a gNodeB and a UE according to QoS requirements, during operation, a request including QoS requirements for at least one of URLLC services, eMMB services, and mMTC services is transmitted to at least one of the functions of the 5GC (e.g., NEF, AMF, SMF, PCF, UPF, etc.), and during operation, a control circuit that provides services using the established PDU session is provided. An application server (e.g., AF of the 5G architecture) is provided.

[0254] The present disclosure can be implemented by software, hardware, or software in cooperation with hardware. Each functional block used in the description of the above embodiments is realized, partially or entirely, as an LSI which is an integrated circuit, and each process described in the above embodiments may be controlled, partially or entirely, by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip so as to include part or all of the functional blocks. The LSI may be provided with data input and output. Depending on the degree of integration, the LSI may also be referred to as an IC, a system LSI, a super LSI, or an ultra LSI.

[0255] The method of integrating into an integrated circuit is not limited to LSI, and it may be realized by an application specific circuit, a general-purpose processor, or a dedicated processor. Further, after manufacturing the LSI, an FPGA (Field Programmable Gate Array) that can be programmed, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing.

[0256] Furthermore, if an integrated circuit technology that replaces the LSI appears due to the progress of semiconductor technology or other derived technologies, naturally, the technology may be used to integrate the functional blocks. The application of biotechnology, etc. may be possible.

[0257] The present disclosure can be implemented in any type of device, apparatus, system having a communication function (collectively referred to as a communication device). The communication device may include a wireless transceiver (transceiver) and a processing / control circuit. The wireless transceiver may include a receiving unit and a transmitting unit, or may include them as functions. The wireless transceiver (transmitting unit, receiving unit) may include an RF (Radio Frequency) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or the like. Non-limiting examples of communication devices include telephones (mobile phones, smartphones, etc.), tablets, personal computers (PCs) (laptops, desktops, notebooks, etc.), cameras (digital still / video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smartwatches, tracking devices, etc.), game consoles, digital book readers, telehealth / telemedicine (remote healthcare / medical prescription) devices, vehicles or mobile transportation means with communication functions (automobiles, airplanes, ships, etc.), and combinations of the above various devices.

[0258] The communication device is not limited to portable or movable ones, and includes any type of device, apparatus, system that is not portable or is fixed, such as smart home devices (household appliances, lighting devices, smart meters or measuring devices, control panels, etc.), vending machines, and any "Things" that can exist on other IoT (Internet of Things) networks.

[0259] Communication includes data communication by cellular systems, wireless LAN systems, communication satellite systems, etc., as well as data communication by combinations thereof.

[0260] In addition, the communication device also includes devices such as a controller and a sensor that are connected or coupled to a communication device that executes the communication function described in the present disclosure. For example, a controller and a sensor that generate control signals and data signals used by the communication device that executes the communication function of the communication device are included.

[0261] In addition, the communication device includes infrastructure facilities such as base stations, access points, and any other devices, apparatuses, and systems that communicate with or control the above-described various non-limiting devices.

[0262] A terminal according to an embodiment of the present disclosure includes a control circuit that determines a cyclic prefix (CP) length coordinated between the terminal and a base station, and a transmission circuit that transmits control information regarding the determined CP length to the terminal.

[0263] In an embodiment of the present disclosure, the control circuit includes any one of a plurality of candidate CP lengths in one of different combinations for each type of channel occupancy time in the control information.

[0264] In an embodiment of the present disclosure, at least one of the candidate CP lengths included in the combination corresponding to the first type is based on Timing alignment (TA), and the candidate CP lengths included in the combination corresponding to the second type are not based on the TA.

[0265] In an embodiment of the present disclosure, at least one of the candidate CP lengths included in the combination corresponding to the first type is based on the category of carrier sense, and the candidate CP lengths included in the combination corresponding to the second type are not based on the category.

[0266] In an embodiment of the present disclosure, the transmission circuit transmits other information regarding scheduling in the time domain that is different from the CP length.

[0267] In one embodiment of the present disclosure, the other information includes information indicating the start timing of the scheduling for the terminal.

[0268] In one embodiment of the present disclosure, the other information includes information indicating candidate timings of channel occupancy time for the terminal.

[0269] In one embodiment of the present disclosure, the control circuit includes any one of a plurality of candidate CP lengths of different combinations for each priority for the terminal or the channel in the control information.

[0270] A terminal according to one embodiment of the present disclosure includes a receiving circuit that receives control information regarding a cyclic prefix (CP) length coordinated between the terminal and a base station, and a control circuit that controls uplink transmission based on the CP length.

[0271] In a communication method according to one embodiment of the present disclosure, a base station determines a cyclic prefix (CP) length coordinated between the terminal and the base station, and transmits control information regarding the determined CP length to the terminal.

[0272] In a communication method according to one embodiment of the present disclosure, a terminal receives control information regarding a cyclic prefix (CP) length coordinated between the terminal and a base station, and controls uplink transmission based on the CP length.

[0273] The disclosures of the specification, drawings, and abstracts included in Japanese Patent Application No. 2020-134799 filed on August 7, 2020 are all incorporated herein by reference.

Industrial Applicability

[0274] One embodiment of the present disclosure is useful for a wireless communication system.

Description of Signs

[0275] 100 Base station 101, 201 Receiver 102,202 Demodulation and Decoding Unit 103,203 Carrier Sense Unit 104 Scheduling Unit 105,205 Control Information Holding Unit 106,206 Data and Control Information Generation Unit 107,207 Encoding and Modulation Unit 108,208 CP Addition Unit 109,209 Transmission Unit 200 Terminal 204 Transmission Control Unit

Claims

1. A control circuit that determines the length of a cyclic prefix (CP), A transmission circuit that transmits control information regarding the determined CP length to a terminal, Comprising, The CP length is made different depending on whether the information indicating the channel occupancy time for the terminal is a first value or a second value different from the first value, Base station.

2. The control circuit sets information regarding different CP lengths for each type of channel occupancy time, The base station according to Claim 1.

3. The CP length corresponding to the first type is based on Timing alignment (TA), The CP length corresponding to the second type is not based on the TA, The base station according to Claim 2.

4. The CP length corresponding to the first type is based on the category of carrier sense, The CP length corresponding to the second type is not based on the category, The base station according to Claim 2.

5. The transmission circuit transmits an index related to a table used to set the CP length, The base station according to Claim 1.

6. The transmission circuit transmits information indicating the start timing of scheduling for the terminal, The base station according to Claim 1.

7. The transmission circuit transmits information indicating candidate timings of the channel occupancy time for the terminal, The base station according to Claim 1.

8. The control circuit sets information regarding different CP lengths for each priority level for the transmission of the terminal, The base station according to Claim 1.

9. The control information is notified in Radio Resource Control (RRC), The base station according to Claim 1.

10. The control information is notified for each terminal, The base station according to Claim 1.

11. The CP length is made different depending on whether the channel occupancy time for the terminal is a first length or a second length different from the first length, The base station according to Claim 1.

12. The CP length is different based on the subcarrier spacing, The base station according to Claim 1.

13. The same CP length can be set depending on whether the channel occupancy time for the terminal is a first length or a second length different from the first length, The base station according to Claim 1.

14. The transmission of the terminal is sidelink transmission, The base station according to Claim 1.

15. The base station is, Determine the cyclic prefix (CP) length, transmit control information regarding the determined CP length to a terminal, and vary the CP length depending on whether information indicating the channel occupancy time for the terminal is a first value or a second value different from the first value, communication method.

16. a control circuit that determines the cyclic prefix (CP) length, a transmission circuit that transmits control information regarding the determined CP length to a terminal, comprising, and varying the CP length depending on whether information indicating the channel occupancy time for the terminal is a first value or a second value different from the first value, integrated circuit.

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