Terminal, base station and communication method

Abstract

The present invention improves reference signal transmission efficiency. A terminal is equipped with: a reception circuit for receiving information indicating some of a plurality of candidate unit-time resources for non-periodic transmission of reference signals; and a control circuit for, on the basis of the information, controlling the allocation of time resources to be used in the transmission of reference signals.

Description

[Technical field]

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

[0002] In Release 17 (hereinafter referred to as "Rel. 17") of the 3rd Generation Partnership Project (3GPP), improvements to the coverage performance or capacity performance of a Sounding Reference Signal (SRS) were discussed in order to expand the functionality of Multiple-Input Multiple Output (MIMO) applied to New Radio access technology (NR) (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] RP-192436, “WID proposal for Rel.17 enhancements on MIMO for NR”, Samsung, December 2019 Summary of the Invention

[0004] However, there is room for improvement in the efficiency of transmitting reference signals.

[0005] Non-limiting embodiments of the present disclosure contribute to providing a terminal, a base station, and a communication method that improve the transmission efficiency of a reference signal.

[0006] A terminal according to one embodiment of the present disclosure includes a receiving circuit that receives information indicating a portion of a plurality of candidate unit time resources for transmitting a non-periodic reference signal, and a control circuit that controls allocation of time resources to be used for transmitting the reference signal based on the information.

[0007] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as 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, it is possible to improve the transmission efficiency of a reference signal.

[0009] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief description of the drawings]

[0010] [Figure 1] A diagram showing an example of 1T4R Antenna switching [Diagram 2] A diagram showing an example of triggering Aperiodic SRS transmission for a 1T4R terminal. [Diagram 3] A diagram showing an example of triggering Aperiodic SRS transmission to a 1T8R terminal. [Figure 4] A diagram showing an example of re-triggering Aperiodic SRS transmission for a 1T8R terminal. [Diagram 5] A block diagram showing an example of the configuration of a portion of a base station. [Figure 6] Block diagram showing an example of a partial configuration of a terminal [Figure 7] Block diagram showing an example of the configuration of a base station [Figure 8] Block diagram showing an example of a terminal configuration [Figure 9] A sequence diagram showing an example of the operation of a base station and a terminal. [Figure 10] A diagram showing an example of an SRS resource set [Figure 11] FIG. 13 is a diagram showing an example of trigger information. [Figure 12]A diagram showing an example of triggering Aperiodic SRS transmission to a 1T8R terminal. [Figure 13] A diagram showing an example of re-triggering Aperiodic SRS transmission for a 1T8R terminal. [Figure 14] A diagram showing an example of re-triggering Aperiodic SRS transmission for a 1T8R terminal. [Figure 15] FIG. 1 is an example architecture diagram of a 3GPP NR system. [Figure 16] Schematic diagram showing the functional separation between NG-RAN (Next Generation - Radio Access Network) and 5GC (5th Generation Core) [Figure 17] Sequence diagram of Radio Resource Control (RRC) connection setup / reconfiguration procedure [Figure 18] A schematic diagram showing the usage scenarios of enhanced Mobile BroadBand (eMBB), massive Machine Type Communications (mMTC), and Ultra Reliable and Low Latency Communications (URLLC). [Figure 19] Block diagram illustrating an example 5G system architecture for a non-roaming scenario DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0012] [SRS] For SRS used in NR (e.g., referred to as "NR SRS"), for example, a base station (e.g., also referred to as "eNB" or "gNB") may notify (or set) information on the setting of SRS (hereinafter referred to as "SRS setting information") to a terminal (e.g., also referred to as "User Equipment (UE)"). In the SRS setting information, for example, an "SRS resource set" which is a parameter set used for each SRS resource such as an SRS transmission timing, an SRS transmission frequency band, a sequence number for generating a reference signal, and a cyclic shift amount may be defined. The SRS setting information may be set by higher layer signaling such as a Radio Resource Control (RRC) layer. In addition, the SRS setting information may be called, for example, "SRS-Config" set in the RRC layer.

[0013] In addition, in the NR SRS, the use case of the SRS, such as downlink channel quality estimation for downlink MIMO transmission (e.g., also referred to as "Antenna switching"), uplink channel quality estimation for uplink MIMO transmission (e.g., also referred to as "Code book" or "Non-code book"), or beam control (e.g., also referred to as "beam management"), may be set in the SRS resource set. For example, the terminal may transmit the SRS according to the use case set in the SRS resource set.

[0014] In addition, the NR SRS may support three types of time domain SRS behaviors, for example, Periodic SRS, Semi-persistent SRS, and Aperiodic SRS. For example, any of the three types of time domain behaviors may be configured in the SRS resource set.

[0015] For example, Periodic SRS and Semi-persistent SRS are SRSs that are periodically transmitted. In Periodic SRS and Semi-persistent SRS, for example, a transmission slot period and a transmission slot offset are set in an SRS resource set, and ON / OFF of transmission may be instructed by at least one of an RRC layer and a Medium Access Control (MAC) layer.

[0016] Also, for example, the aperiodic SRS is an SRS that is transmitted non-periodically. In the aperiodic SRS, for example, the transmission timing may be indicated by trigger information (for example, "SRS resource indicator (SRI)") included in a downlink control channel of the physical layer (for example, Physical Downlink Control Channel (PDCCH)). For example, a terminal may transmit the aperiodic SRS when aperiodic SRS transmission is requested by trigger information. For example, the terminal may transmit the aperiodic SRS at a timing after a slot offset set in the SRS resource set by the RRC layer from the slot in which the trigger information is received. The base station becomes able to dynamically (or instantly) instruct the terminal to transmit the aperiodic SRS, for example, at the timing of performing channel estimation using a predetermined band or transmission beam.

[0017] [Antenna port] The NR SRS supports, for example, a function called antenna switching. In antenna switching, for example, a terminal that has a different number of transmit antenna ports and a different number of receive antenna ports that can be simultaneously processed (for example, the number of transmit antenna ports is smaller) may perform downlink channel quality estimation for downlink MIMO transmission.

[0018] FIG. 1 is a diagram showing an example of antenna switching in a terminal (also called a "1T4R" terminal) that can simultaneously process one transmitting antenna port (sometimes expressed as one transmission (1Tx)) and four receiving antenna ports (sometimes expressed as four receptions (4Rx)).

[0019] As shown in FIG. 1, a terminal having fewer transmitting antenna ports than receiving antenna ports, for example, switches the antenna port (for example, TX antenna) that transmits SRS over time. This allows the base station to estimate the quality of all spatial channels in an environment where reversibility of channel characteristics can be assumed between downlink (DL) and uplink (UL), such as Time Division Duplexing (TDD). The base station can improve DL MIMO performance by, for example, calculating the transmission weight in DL MIMO transmission using SRS.

[0020] For example, in the specifications for the NR licensed band, the symbol in which the SRS is placed (hereinafter also referred to as the "SRS symbol") can be placed in the last six symbols of the slot.

[0021] In this case, for example, 1T4R antenna switching may be set using two slots (for example, two SRS resource sets). For example, FIG. 2 is a diagram showing an example of transmission of SRS (for example, aperiodic SRS) in 1T4R antenna switching. As shown in FIG. 2, for example, in SRS resource set number 0 (for example, SRS resource set 0) and SRS resource set number 1 (for example, SRS resource set 1) set by the RRC layer, transmission slot timings of slot offset=1 and slot offset=2 may be set. Also, the same trigger number (for example, trigger number=1) may be set in SRS resource set number 0 and SRS resource set number 1. Also, for example, SRS resource for three symbols (for example, SRS resource numbers 0, 1, 2) may be set in SRS resource set number 0, and SRS resource for one symbol (for example, SRS resource number 3) may be set in SRS resource set number 1. In addition, in FIG. 2, the "GAP" between SRS symbols may be, for example, a time set for a terminal to physically switch a transmitting antenna port.

[0022] As in the example shown in Fig. 2, the base station may instruct a 1T4R terminal to transmit aperiodic SRS using two slots (or two SRS resource sets) for antenna switching by using trigger information (trigger number = 1 in Fig. 2). The terminal may transmit aperiodic SRS by switching the transmitting antenna port by antenna switching in the two slots based on the trigger information, for example.

[0023] In Rel. 17, for example, in order to expand the functionality of MIMO in NR, it was considered to increase the upper limit of the number of transmitting antenna ports for SRS from 4 to 8, and to support 1T8R terminals (for example, see Non-Patent Document 1).

[0024] However, a method for triggering aperiodic SRS transmission for antenna switching purposes to 1T8R terminals has not been fully studied.

[0025] Fig. 3 is a diagram showing an example in which a base station triggers aperiodic SRS transmission for a 1T8R terminal in the use of antenna switching. Fig. 3 shows an example in which a triggering method for a 1T4R terminal (for example, Fig. 2) is extended. As shown in Fig. 3, a base station may trigger SRS transmission using three different slots (or three different SRS resource sets) for a 1T8R terminal.

[0026] Here, in NR, the slot format can be dynamically updated by the base station using downlink control information (e.g., DCI: Downlink Control Information) (e.g., DCI format 2-0). On the other hand, the slot offset of the SRS resource set set by the RRC layer is not dynamically changed. For this reason, in the terminal, a case may occur in which an uplink signal including an SRS is not transmitted in a slot that is an SRS transmission timing due to a change in the slot format. In this case, since the terminal does not transmit an SRS in a slot (e.g., a downlink slot) where an uplink signal cannot be transmitted, the base station may re-trigger the terminal to transmit an aperiodic SRS using, for example, three slots.

[0027] Fig. 4 is a diagram showing an example of SRS transmission when the slot format is changed at the SRS transmission timing of a terminal. Note that SRS port 0-2 shown in Fig. 4 means that SRS symbols set by SRS resource numbers 0 to 2 are transmitted using antenna ports 0 to 2.

[0028] In the example shown in Fig. 4, of the three slots instructed to transmit SRS by the PDCCH (e.g., DCI), the second and third slots are changed from uplink slots to downlink slots. In this case, the terminal transmits the SRS in the first slot, but does not transmit (in other words, drops) the SRS in the second and third slots. In this case, as shown in Fig. 4, the base station may re-trigger the transmission of SRS in all three slots, including the SRS in the first slot that the terminal has already transmitted.

[0029] As described above, with regard to triggering aperiodic SRS transmission using multiple slots, a method of triggering SRS transmission of some slots (or SRS resource sets or SRS transmitting antenna ports) has not been considered. Therefore, as described above, if SRS transmission is not performed in some slots among the multiple slots used for SRS transmission, SRS transmission using multiple slots including the slot in which SRS transmission was performed (in other words, the slot that does not need to be triggered again) will be triggered again, which may reduce the SRS transmission efficiency. For example, an increase in overhead due to SRS transmission may degrade system performance in the uplink.

[0030] Therefore, in one embodiment of the present disclosure, a method for improving the transmission efficiency of an SRS by enabling flexible scheduling of an aperiodic SRS for a terminal will be described.

[0031] Note that cases where SRS transmission of some slots (or antenna ports) is triggered are not limited to cases where SRS transmission is triggered by dynamic change of slot format as described above. For example, when a terminal prioritizes data transmission from some antenna ports over SRS transmission, there may be cases where SRS transmission of some slots (or antenna ports) is triggered in order to prioritize improving channel estimation accuracy by the SRS transmitted from the some antenna ports.

[0032] [Communication system overview] A communication system according to one embodiment of the present disclosure may include, for example, a base station 100 (e.g., a gNB or an eNB) and a terminal 200 (e.g., a UE).

[0033] For example, base station 100 may be a base station for NR, and terminal 200 may be a terminal for NR. Base station 100 may trigger, for example, terminal 200 to transmit at least a portion of an Aperiodic SRS using multiple slots, and receive the corresponding Aperiodic SRS. Furthermore, terminal 200 may transmit at least a portion of an Aperiodic SRS using multiple slots, for example, based on trigger information from base station 100.

[0034] Fig. 5 is a block diagram showing a configuration example of a part of base station 100 according to an embodiment of the present disclosure. In base station 100 shown in Fig. 5, transmission unit 104 transmits information (e.g., trigger information) indicating a part of a plurality of candidate unit time resources (e.g., slots) for transmitting a non-periodic reference signal (e.g., Aperiodic SRS) by terminal 200. Control unit 101 controls allocation of time resources used for receiving reference signals based on, for example, the above information.

[0035] Fig. 6 is a block diagram showing a configuration example of a part of terminal 200 according to an embodiment of the present disclosure. In terminal 200 shown in Fig. 6, receiving unit 201 receives information (e.g., trigger information) indicating a part of a plurality of candidate unit time resources (e.g., slots) for transmitting a non-periodic reference signal (e.g., Aperiodic SRS). Control unit 203 controls allocation of time resources used for transmitting the reference signal based on the information.

[0036] [Base station configuration] Fig. 7 is a block diagram showing a configuration example of a base station 100 according to an embodiment of the present disclosure. In Fig. 7, the base station 100 may include, for example, a control unit 101, a coding and modulation unit 102, a transmission processing unit 103, a transmission unit 104, a reception unit 105, a reception processing unit 106, a data signal reception unit 107, and a reference signal reception unit 108.

[0037] The control unit 101 may control, for example, the scheduling of the SRS. For example, the control unit 101 may generate SRS setting information or downlink control information (for example, DCI) used for a transmission request of the aperiodic SRS for the terminal 200 that is to trigger the transmission of the aperiodic SRS.

[0038] The SRS resource set of the SRS setting information may include parameters such as the transmission frequency band of each SRS resource (e.g., including the number of transmission Combs), the transmission symbol position, the number of SRS ports or port numbers, the sequence number for generating a reference signal, the amount of cyclic shift (e.g., cyclic shift value), frequency hopping, or sequence hopping.

[0039] For example, multiple SRS resource sets can be set in the SRS configuration information. Also, for example, one or multiple trigger numbers that can be notified by trigger information may be set in each SRS resource set for aperiodic SRS. Terminal 200 may apply the SRS resource set associated with the trigger number notified by the trigger information.

[0040] DCI may include, for example, several bits of trigger information (for example, an SRI field) of the aperiodic SRS. For example, trigger numbers of the aperiodic SRS (for example, an SRS resource set for the aperiodic SRS), the number of which corresponds to the number of bits of the trigger information (for example, the number of values ​​that can be expressed by the bits of the trigger information), may be associated with the values ​​that can be expressed by the bits of the trigger information. For example, when the trigger information is two bits (for example, four values ​​that can be expressed), "No SRS transmission request (or No Trigger)" and three trigger numbers of the aperiodic SRS may be associated with the trigger information. When the trigger information is two bits, base station 100 may trigger terminal 200 to transmit aperiodic SRS, each associated with, for example, three different trigger numbers.

[0041] Note that multiple SRS resource sets may be associated with one trigger number. This association makes it possible to trigger aperiodic SRS transmission using multiple slots, for example, by one piece of trigger information. For example, base station 100 may instruct a 1T4R terminal or a 1T8R terminal to transmit aperiodic SRS for the purpose of antenna switching, based on the association between trigger information and SRS resource sets.

[0042] Also, for example, a plurality of trigger numbers may be associated with an SRS resource set set for each slot. For example, the number of trigger numbers associated with an SRS resource set may differ between different SRS resource sets. With this association, for example, base station 100 can trigger SRS transmission for an SRS resource set set in some slots among a plurality of slots.

[0043] The control unit 101 may output control information including the SRS setting information generated as described above to the coding and modulation unit 102. The SRS setting information may be transmitted to the target terminal 200 after transmission processing is performed in the coding and modulation unit 102, the transmission processing unit 103, and the transmission unit 104 as control information of the RRC layer (in other words, higher layer signaling or RRC signaling), for example.

[0044] Furthermore, control unit 101 may output DCI including trigger information for aperiodic SRS transmission, generated as described above, to coding and modulation unit 102. The DCI may be transmitted to target terminal 200 after transmission processing is performed in coding and modulation unit 102, transmission processing unit 103, and transmission unit 104 as layer 1 or layer 2 control information, for example.

[0045] As described above, the SRS setting information may be notified from base station 100 to terminal 200 by, for example, higher layer signaling, while DCI including trigger information may be notified from base station 100 to terminal 200 by PDCCH. For example, since the reporting interval (or transmission interval) of DCI is shorter than that of SRS setting information, base station 100 can dynamically (or instantaneously) notify trigger information according to the communication status of each terminal 200.

[0046] Furthermore, the control unit 101 may control reception of the Aperiodic SRS based on, for example, the SRS setting information and the trigger information. For example, the control unit 101 may output the SRS setting information and the trigger information to the reception processing unit 106 and the reference signal receiving unit 108.

[0047] In addition to the trigger information of the Aperiodic SRS, the DCI may include other information such as allocation information of frequency resources (e.g., Resource Blocks (RBs)) for uplink data or downlink data, and data coding and modulation method (e.g., Modulation and Coding Scheme (MCS)) information. The control unit 101 may output, for example, the allocation information of radio resources for downlink data transmission to the transmission processing unit 103.

[0048] Furthermore, for example, when the base station 100 changes the slot format, the control unit 101 may generate information about the slot format. For example, the control unit 101 may output DCI including the information about the slot format to the coding and modulation unit 102.

[0049] The coding and modulation unit 102 may, for example, code and modulate the SRS setting information or DCI input from the control unit 101 and output the obtained modulated signal to the transmission processing unit 103. The coding and modulation unit 102 may also code and modulate an input data signal (or transmission data) and output the obtained modulated signal to the transmission processing unit 103.

[0050] The transmission processing unit 103 may form a transmission signal by, for example, mapping the modulated signal input from the coding and modulation unit 102 to a frequency band in accordance with allocation information of radio resources for downlink data transmission input from the control unit 101. For example, when the transmission signal is an Orthogonal Frequency Division Multiplexing (OFDM) signal, the transmission processing unit 103 may form an OFDM signal by mapping the modulated signal to a frequency resource, converting it into a time waveform by performing an Inverse Fast Fourier Transform (IFFT) process, and adding a CP (Cyclic Prefix).

[0051] The transmitting unit 104 may, for example, perform transmission radio processing such as up-conversion and digital-to-analog (D / A) conversion on the transmission signal input from the transmission processing unit 103, and transmit the transmission signal after transmission radio processing via an antenna.

[0052] The receiving unit 105 may perform reception radio processing such as down-conversion and analog-to-digital (A / D) conversion on a radio signal received via an antenna, and output the received signal after reception radio processing to the reception processing unit 106.

[0053] The reception processing unit 106 may, for example, based on information input from the control unit 101, identify the resource to which the uplink data signal is mapped, and extract the signal component mapped to the identified resource from the received signal.

[0054] Furthermore, reception processing unit 106 may identify a resource to which the Aperiodic SRS is mapped, based on the SRS setting information and DCI (e.g., trigger information) input from control unit 101, and extract a signal component mapped to the identified resource from the received signal. For example, reception processing unit 106 may receive the Aperiodic SRS at a slot timing obtained by adding a slot offset set in the SRS resource set(s) associated with the trigger number of the Aperiodic SRS indicated by the trigger information to the slot at which the DCI was transmitted.

[0055] The reception processing unit 106 may specify the resource to which the Aperiodic SRS is mapped, for example, based on the slot format. For example, even if the slot timing to which the Aperiodic SRS can be mapped is not an uplink slot (for example, a downlink slot), the reception processing unit 106 may not need to perform reception processing of the SRS.

[0056] The reception processing unit 106 outputs, for example, the extracted uplink data signal to a data signal receiving unit 107 and outputs the Aperiodic SRS signal to a reference signal receiving unit 108.

[0057] The data signal receiving unit 107 may, for example, decode the signal input from the reception processing unit 106 and output the upstream data (or the received data).

[0058] Reference signal receiving unit 108 may measure the reception quality of each frequency resource based on, for example, the Aperiodic SRS signal input from reception processing unit 106 and parameter information of the SRS resource set input from control unit 101, and output information related to the reception quality. Here, reference signal receiving unit 108 may perform channel quality measurement using a desired Aperiodic SRS by identifying the antenna port applied to the Aperiodic SRS transmitted from target terminal 200 and the symbol position within the slot based on, for example, SRS setting information and DCI (e.g., trigger information) input from control unit 101.

[0059] [Device configuration] Fig. 8 is a block diagram showing a configuration example of terminal 200 according to an embodiment of the present disclosure. In Fig. 8, terminal 200 may include, for example, receiving unit 201, receiving processing unit 202, control unit 203, reference signal generating unit 204, data signal generating unit 205, transmission processing unit 206, and transmitting unit 207.

[0060] The receiving unit 201 may perform reception radio processing such as down-conversion and analog-to-digital (A / D) conversion on a radio signal received via an antenna, and output the received signal after reception radio processing to the reception processing unit 202.

[0061] The reception processing unit 202 may, for example, extract SRS setting information and DCI included in the received signal input from the reception unit 201, and output the extracted information to the control unit 203. The reception processing unit 202 may also, for example, decode a downlink data signal included in the received signal, and output the decoded downlink data signal (or received data). Note that, when the received signal is an OFDM signal, the reception processing unit 202 may, for example, perform CP removal processing and Fast Fourier Transform (FFT) processing.

[0062] The control unit 203 may control the transmission of the Aperiodic SRS based on, for example, the SRS setting information and DCI (e.g., trigger information) input from the reception processing unit 202. For example, when the control unit 203 detects an instruction from the base station 100 regarding the Aperiodic SRS transmission from the trigger information, the control unit 203 identifies an SRS resource set to be used for transmitting the Aperiodic SRS based on the SRS setting information and the trigger information. Then, the control unit 203 may extract SRS resource information (e.g., frequency resource information and reference signal information, etc.) to be applied to the Aperiodic SRS based on, for example, the identified SRS resource set, and output (or instruct or set) the SRS resource information to the reference signal generating unit 204.

[0063] For example, when terminal 200 is a 1T8R terminal and aperiodic SRS transmission for antenna switching is triggered, terminal 200 may switch the transmitting antenna port from eight antenna ports one symbol at a time to transmit the SRS. Terminal 200 may transmit the aperiodic SRS using up to three SRS resource sets (in other words, three slots) when, for example, the number of SRS resources included in one SRS resource set is up to three (in other words, when the SRS that can be transmitted in one slot is three symbols). Under this condition, for example, each of the three SRS resource sets (for example, SRS transmission using one to three slots) may be associated with one or more trigger numbers. Terminal 200 may, for example, identify an SRS resource set associated with a trigger number and transmit an SRS corresponding to the identified SRS resource set. For example, when the number of trigger numbers associated with the above-mentioned three SRS resource sets is different, the number of slots to be used for SRS transmission instructed to terminal 200 can be variably set according to the trigger number notified from base station 100. Note that the maximum number of SRS resources included in one SRS resource set is not limited to three.

[0064] In addition, the control unit 203 may, for example, identify frequency resource information and MCS to which the uplink data signal is mapped based on the DCI input from the reception processing unit 202, output the frequency resource information to the transmission processing unit 206, and output the MCS information to the data signal generation unit 205.

[0065] Furthermore, control unit 203 may, for example, identify an SRS resource set used for aperiodic SRS, and output information indicating an antenna port number for SRS transmission using the SRS resource set to transmission unit 207. Furthermore, control unit 203 may, for example, extract an antenna port number for transmitting data from DCI, and output information indicating the antenna port number to transmission unit 207.

[0066] For example, when the reference signal generating unit 204 receives an instruction to generate a reference signal from the control unit 203, the reference signal generating unit 204 may generate a reference signal (e.g., an aperiodic SRS) based on the SRS resource information input from the control unit 203, and output the reference signal to the transmission processing unit 206.

[0067] The data signal generating unit 205 may generate a data signal by, for example, encoding and modulating the input transmission data (or an uplink data signal) based on the MCS information input from the control unit 203. The data signal generating unit 205 may output the generated data signal to the transmission processing unit 206, for example.

[0068] For example, the transmission processing unit 206 may map the Aperiodic SRS input from the reference signal generating unit 204 to a frequency resource instructed by the control unit 203. Also, for example, the transmission processing unit 206 may map the data signal input from the data signal generating unit 205 to a frequency resource instructed by the control unit 203. In this way, a transmission signal is formed. Note that, when the transmission signal is an OFDM signal, the transmission processing unit 206 may, for example, perform IFFT processing on the signal after mapping to the frequency resource, and add a CP.

[0069] The transmitting unit 207 may perform transmission radio processing such as up-conversion and digital-to-analog (D / A) conversion on the transmission signal formed in the transmission processing unit 206, and transmit the signal after the transmission radio processing via an antenna. When transmitting an SRS, for example, the transmitting unit 207 may switch the antenna port for transmitting the SRS based on information on the antenna port number for each SRS symbol input from the control unit 203. When transmitting a data signal, for example, the transmitting unit 207 may switch the antenna port for transmitting the data signal based on information on the antenna port number input from the control unit 203.

[0070] [Operation of base station 100 and terminal 200] An example of the operation of base station 100 and terminal 200 having the above configuration will be described.

[0071] FIG. 9 is a sequence diagram showing an example of the operation of base station 100 and terminal 200. In FIG.

[0072] Base station 100 performs, for example, configuration related to an aperiodic SRS transmission instruction for terminal 200 (S101). For example, base station 100 may generate SRS configuration information including an SRS resource set (or a slot) used for aperiodic SRS transmission.

[0073] Base station 100 transmits (or sets or notifies) SRS configuration information to terminal 200 by, for example, higher layer signaling (for example, an RRC layer signal) (S102).

[0074] Furthermore, for example, at the time of an SRS transmission request, base station 100 transmits to terminal 200 downlink control information (for example, DCI) including trigger information indicating any of the SRS setting information (for example, SRS resource set) configured in terminal 200 (S103).

[0075] Terminal 200 generates an Aperiodic SRS based on, for example, the SRS setting information and trigger information transmitted from base station 100 (S104). Terminal 200 transmits, for example, the generated Aperiodic SRS to base station 100 (S105). For example, terminal 200 may determine an antenna port (or a slot) for transmitting the Aperiodic SRS based on the SRS setting information and the trigger information. Base station 100 receives the Aperiodic SRS from terminal 200 based on, for example, the SRS setting information and the trigger information transmitted to terminal 200.

[0076] [How to generate trigger information for Aperiodic SRS] An example of a method for generating trigger information for an Aperiodic SRS in base station 100 (for example, control unit 101) will be described.

[0077] For example, base station 100 may generate trigger information capable of instructing SRS transmission of some slots in aperiodic SRS transmission using multiple slots such as for antenna switching. In other words, base station 100 may generate information instructing some of multiple slots for transmission of aperiodic SRS by terminal 200.

[0078] Fig. 10 is a diagram showing an example of an SRS resource set (for example, SRS resource information for each slot set in terminal 200). Fig. 11 is a diagram showing an example of trigger information. The SRS resource set may be set in terminal 200 by, for example, the RRC layer. The trigger information may be reported to terminal 200 by, for example, DCI.

[0079] As shown in FIG. 10, at least one of "purpose", "resource type", and "SRS resource" may be set in the SRS resource set.

[0080] In "purpose", for example, the purpose of the SRS, such as antenna switching or beam management, may be set. Terminal 200 may perform an operation according to the purpose set in the SRS resource set. For example, when the purpose is antenna switching, terminal 200 may switch the antenna port to transmit for each SRS resource.

[0081] In "Resource type," for example, any one of the types of time domain SRS behavior, such as aperiodic transmission, semi-persistent transmission, or periodic transmission, may be set. For example, when the resource type is aperiodic transmission, a trigger number and a slot offset may be set for terminal 200 as shown in FIG.

[0082] As shown in Fig. 10, one or more trigger numbers (e.g., also referred to as "aperiodicSRS-ResourceTrigger") may be associated with each SRS resource set. In Fig. 10, one of a plurality of values ​​(trigger numbers = 0 to 3 in Fig. 11) represented by bits of trigger information (two bits in Fig. 11) may be associated with an SRS resource set corresponding to each of a plurality of slots (e.g., slot offset = any one of 1 to 3) used for aperiodic SRS transmission.

[0083] Also, for example, the number of trigger information values ​​(e.g., trigger numbers) associated with different SRS resource sets (in other words, different slots) is different. In the example shown in Fig. 10, trigger number = 1 (in other words, 1 value) is associated with SRS resource set #0, trigger numbers = 1 and 2 (in other words, 2 values) are associated with SRS resource set #1, and trigger numbers = 1, 2, and 3 (in other words, 3 values) are associated with SRS resource set #2.

[0084] In other words, in the example shown in Fig. 10, for example, information (e.g., SRS resource set) relating to each of three slots (slot offsets = 1 to 3) is associated with trigger number = 1 (e.g., the same value) among multiple values ​​represented by bits of trigger information. Similarly, in the example shown in Fig. 10, for example, SRS resource sets relating to each of two slots (slot offsets = 2 and 3) are associated with trigger number = 2 (e.g., the same value) among multiple values ​​represented by bits of trigger information.

[0085] "SRS resource" may include, for example, SRS resource information in a slot. SRS resource information may include, for example, parameters such as the number of transmitting antenna ports (or port number), transmitting symbol position, or sequence information. For example, in FIG. 10, a combination of a transmitting antenna port number (e.g., any one of #0 to #7) and a transmitting symbol position (e.g., any one of the 9th symbol, 11th symbol, or 13th symbol in a slot) may be set in each of SRS resources #0 to #7 set in each SRS resource set.

[0086] Also, as shown in Fig. 11, possible values ​​of trigger information included in DCI depending on the number of bits may be associated with trigger numbers. In the example shown in Fig. 11, since the trigger information is two bits (e.g., four values ​​from 0 to 3), one value (e.g., trigger information = 0) may be associated with "no Aperiodic SRS transmission (No trigger)," and three values ​​(e.g., trigger information = 1 to 3) may be associated with different trigger numbers.

[0087] For example, when the SRS resource set shown in FIG. 10 is configured for terminal 200, base station 100 can trigger terminal 200 to transmit aperiodic SRS using 3 slots, 2 slots, and 1 slot by instructing trigger information=1, 2, and 3, respectively, as shown in FIG. 11.

[0088] FIG. 12 is a diagram showing an example of triggering aperiodic SRS transmission to terminal 200 of 1T8R.

[0089] In the example shown in FIG. 12, base station 100 notifies terminal 200 of trigger information=2 by DCI. For example, in FIG. 11, trigger information=2 is associated with trigger number=2. Also, for example, in FIG. 10, trigger number=2 is associated with SRS resource set numbers=1 and 2. Therefore, in FIG. 12, base station 100 can instruct terminal 200 to transmit aperiodic SRS using the SRS resource of the second slot (or slot offset=2) corresponding to SRS resource set number=1 (for example, antenna port numbers=3 to 5 and transmission symbol positions=9, 11th and 13th symbols) and the SRS resource of the third slot (or slot offset=3) corresponding to SRS resource set number=2 (for example, antenna port numbers=6 to 7 and transmission symbol positions=9th and 11th symbols).

[0090] 12, for example, terminal 200 transmits an aperiodic SRS using the SRS resources of the second and third slots from the slot in which the trigger information (or PDCCH) is received, based on trigger number 2 indicated in the trigger information. In other words, in Fig. 12, terminal 200 does not need to transmit an aperiodic SRS using the SRS resource of the first slot (e.g., slot offset = 1) from the slot in which the trigger information is received.

[0091] In this way, base station 100 can trigger SRS transmission in some slots (e.g., slot offsets = 2 and 3) when triggering aperiodic SRS transmission using, for example, the three slots (e.g., slot offsets = 1 to 3) shown in Fig. 12. In other words, base station 100 does not need to trigger SRS transmission in the slot corresponding to slot offset = 1 among the three slots shown in Fig. 12.

[0092] For example, base station 100 may transmit to terminal 200 a trigger number (trigger number=2 in FIG. 2) that is associated with SRS resource sets corresponding to some slots (e.g., slot offset=2 and 3) among the SRS resource sets shown in FIG. 10 and is not associated with an SRS resource set corresponding to other slots (e.g., slot offset=1).

[0093] Fig. 13 is a diagram showing an example of triggering aperiodic SRS transmission using three slots. In Fig. 13, for example, of the three slots used for aperiodic SRS transmission, the second slot (e.g., SRS port #3-5) and the third slot (e.g., SRS port #6-7) are changed from uplink slots to downlink slots, and terminal 200 does not transmit aperiodic SRS (for example, drops it).

[0094] In this case, base station 100 may re-trigger aperiodic SRS transmission to terminal 200. When re-triggering aperiodic SRS transmission, in Fig. 13, for example, base station 100 can trigger SRS transmission in the second and third slots by trigger information=2 shown in Fig. 11. In other words, base station 100 does not trigger SRS transmission in the first slot in which aperiodic SRS is transmitted from terminal 200.

[0095] As described above, in this embodiment, base station 100 transmits trigger information indicating some of a plurality of slots (e.g., candidate unit time resources) for transmitting an aperiodic SRS by terminal 200, and terminal 200 receives the trigger information. In this way, in aperiodic SRS transmission using a plurality of slots, base station 100 can dynamically instruct terminal 200 to transmit SRS in some of the slots.

[0096] Therefore, for example, even if SRS transmission is not performed in some slots out of a plurality of slots used for SRS transmission, there is no need to re-trigger SRS transmission using the slots in which SRS transmission has been performed (in other words, slots that do not need to be re-triggered), thereby improving SRS transmission efficiency. As described above, according to the present embodiment, base station 100 can flexibly schedule aperiodic SRS transmission for terminal 200, and can, for example, suppress an increase in overhead due to SRS transmission and improve system performance in the uplink.

[0097] An embodiment of the present disclosure has been described above.

[0098] In this embodiment, the use of SRS is not limited to "antenna switching" in which terminal 200 switches the antenna port for transmitting the aperiodic SRS for each of a number of slots. For example, this embodiment may be applied to aperiodic SRS transmission in which the antenna port is switched over a number of slots, such as beam management that controls an uplink transmission antenna port.

[0099] In addition, in the present embodiment, for example, as shown in FIG. 10, a case has been described in which the transmitting antenna port number is explicitly set in the SRS resource in the SRS resource set, but the transmitting antenna port number does not have to be explicitly set in the SRS resource. For example, the antenna port number corresponding to the SRS resource may be implicitly recognized between the base station 100 and the terminal 200. For example, when an aperiodic SRS for antenna switching is set for the 1T8R terminal 200, eight SRS resources may be set by multiple SRS resource sets. In this case, the terminal 200 may determine the transmitting antenna port number in order from the SRS symbol for which the transmission resource is set earliest, based on, for example, the set slot offset and the transmission symbol position. Alternatively, the transmitting antenna port number may be explicitly included in the SRS resource. As a result, for example, the relationship between the SRS resource and the antenna port number as shown in FIG. 10 can be recognized between the base station 100 and the terminal 200.

[0100] Furthermore, for example, when terminal 200 drops SRS transmission of some slots among a plurality of slots in which aperiodic SRS transmission is triggered (in other words, when stopping transmission), terminal 200 does not need to change the antenna port used for SRS transmission of each slot (in other words, the association between slots and antenna ports). For example, a plurality of slots in which aperiodic SRS transmission is triggered may be associated with an SRS transmission antenna port. Base station 100 and terminal 200 may determine an antenna port to be used for SRS transmission in each of some slots based on, for example, the association between each of a plurality of slots and a transmission antenna port.

[0101] FIG. 14 is a diagram showing an example of triggering aperiodic SRS transmission to terminal 200 of 1T8R. In FIG. 14, terminal 200 drops the SRS in the second slot and transmits SRS in the first and third slots. In this case, in the SRS transmission in the third slot, terminal 200 may transmit SRS in order from antenna port number 6 associated with the SRS resource in the third slot, rather than transmitting SRS in order from antenna port number 3 corresponding to the dropped SRS. For example, base station 100 has difficulty in grasping a reception error (or reception miss) of PDCCH (or DCI) in terminal 200. As described above, by previously associating each slot used by terminal 200 for SRS transmission with an antenna port number used in each slot, base station 100 can suppress occurrence of a recognition error of antenna port number between base station 100 and terminal 20 even when SRS transmission in the second slot is triggered again in FIG. 14, for example.

[0102] In addition, the above-mentioned dropping rule (the rule that the antenna port used for SRS transmission of each slot should not be changed even if some slots are dropped) is not limited to Aperiodic SRS, but may also be applied when transmitting by switching antenna ports across multiple slots in Semi-Persistent SRS or Periodic SRS.

[0103] In addition, in the above-mentioned embodiment, the terminal is described as being 1T4R or 1T8R, but the number of transmit antenna ports and the number of receive antenna ports that can be processed simultaneously are not limited to these. Also, the symbol position where the SRS is arranged is not limited to the above-mentioned example.

[0104] In addition, in an embodiment of the present disclosure, the target of resource information such as a transmitting antenna port or a transmitting symbol position is not limited to a reference signal such as an SRS, and may be other signals (or information). For example, an embodiment of the present disclosure may be applied to a response signal to data (e.g., also called an ACK / NACK or HARQ-ACK) instead of an SRS.

[0105] In addition, in one embodiment of the present disclosure, a case has been described in which the SRS configuration information is configured in terminal 200 by higher layer signaling (e.g., RRC layer signaling), but the configuration of the SRS configuration information is not limited to higher layer signaling and may be other signaling (e.g., physical layer signaling). In addition, a case has been described in which the trigger information is notified to terminal 200 by DCI, but the trigger information may be notified to terminal 200 by a signal (or information) different from DCI.

[0106] (Control signal) In one 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) in the physical layer, or a signal (or information) transmitted in a Medium Access Control (MAC) or Radio Resource Control (RRC) in a higher layer. In addition, the signal (or information) is not limited to being notified by a downlink control signal, and may be predefined in a specification (or standard), or may be preconfigured in the base station and the terminal.

[0107] In one 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 a physical layer, or a signal (or information) transmitted in a MAC or RRC of a higher layer. Furthermore, the signal (or information) is not limited to being notified by an uplink control signal, and may be predefined in a specification (or standard), or may be preconfigured in a base station and a terminal. Furthermore, the uplink control signal may be replaced with, for example, uplink control information (UCI), 1st stage sidelink control information (SCI), or 2nd stage SCI.

[0108] (base station) In an 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 parent device, a gateway, etc. In addition, in sidelink communication, a terminal may be used instead of the base station. In addition, a relay device that relays communication between an upper node and a terminal may be used instead of the base station.

[0109] (Uplink / Downlink / Sidelink) An embodiment of the present disclosure may be applied to, for example, any of an uplink, a downlink, and a sidelink. For example, an 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) of an uplink, a Physical Downlink Shared Channel (PDSCH), a PDCCH, a Physical Broadcast Channel (PBCH) of a downlink, or a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Broadcast Channel (PSBCH) of a sidelink.

[0110] The PDCCH, PDSCH, PUSCH, and PUCCH are examples of a downlink control channel, a downlink data channel, an uplink data channel, and an uplink control channel, respectively. The PSCCH and PSSCH are examples of a sidelink control channel and a sidelink data channel, respectively. The PBCH and PSBCH are examples of a broadcast channel, and the PRACH is an example of a random access channel.

[0111] (Data Channel / Control Channel) An embodiment of the present disclosure may be applied to, for example, any of a data channel and a control channel. For example, the channel in an embodiment of the present disclosure may be replaced with any of the data channels PDSCH, PUSCH, and PSSCH, or the control channels PDCCH, PUCCH, PBCH, PSCCH, and PSBCH.

[0112] (reference signal) In one embodiment of the present disclosure, the reference signal is, for example, a signal known by both the base station and the mobile station, and may be called a Reference Signal (RS) or a pilot signal. The reference signal may be any of a Demodulation Reference Signal (DMRS), a Channel State Information - Reference Signal (CSI-RS), a Tracking Reference Signal (TRS), a Phase Tracking Reference Signal (PTRS), a Cell-specific Reference Signal (CRS), or a Sounding Reference Signal (SRS).

[0113] (Time Interval) In an embodiment of the present disclosure, the unit of time resource is not limited to one or a combination of slots and symbols, but may be, for example, a time resource unit such as a frame, a superframe, a subframe, a slot, a time slot subslot, a minislot, or a symbol, an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier-Frequency Division Multiplexing (SC-FDMA) symbol, or another time resource unit. Also, the number of symbols included in one slot is not limited to the number of symbols exemplified in the above embodiment, and may be another number of symbols.

[0114] (Frequency band) An embodiment of the present disclosure may be applied to either a licensed band or an unlicensed band.

[0115] (communication) An 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 an embodiment of the present disclosure may be replaced with any of PSCCH, PSSCH, Physical Sidelink Feedback Channel (PSFCH), PSBCH, PDCCH, PUCCH, PDSCH, PUSCH, and PBCH.

[0116] Moreover, an embodiment of the present disclosure may be applied to any of terrestrial networks, non-terrestrial networks (NTNs) using satellites or High Altitude Pseudo Satellites (HAPSs), etc. Furthermore, an embodiment of the present disclosure may be applied to terrestrial networks in which the transmission delay is large compared to the symbol length or slot length, such as networks with large cell sizes and ultra-wideband transmission networks.

[0117] (Antenna port) In one embodiment of the present disclosure, an antenna port refers to a logical antenna (antenna group) consisting of one or more physical antennas. For example, an antenna port does not necessarily refer to one physical antenna, but may refer to an array antenna consisting of multiple antennas. For example, the number of physical antennas that an antenna port is composed of is not specified, and the antenna port may be specified as the minimum unit by which a terminal station can transmit a reference signal. In addition, an antenna port may be specified as the minimum unit for multiplying a weight of a precoding vector.

[0118] <5G NR system architecture and protocol stack> 3GPP continues to work on the next release of the fifth generation of mobile phone technology (also known simply as "5G"), which includes the development of a new radio access technology (NR) that will operate in the frequency range up to 100 GHz. The first version of the 5G standard was completed at the end of 2017, which will allow for the prototyping and commercial deployment of 5G NR compliant devices (e.g. smartphones).

[0119] For example, the system architecture generally assumes a Next Generation - Radio Access Network (NG-RAN) with gNBs. The gNBs provide UE-side termination of NG radio access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocols. The gNBs are connected to each other by an Xn interface. The gNBs are also connected to a Next Generation Core (NGC) by a Next Generation (NG) interface, more specifically to an Access and Mobility Management Function (AMF) (e.g., a specific core entity performing AMF) by an NG-C interface, and to a User Plane Function (UPF) (e.g., a specific core entity performing UPF) by an NG-U interface. The NG-RAN architecture is shown in Figure 15 (see, e.g., 3GPP TS 38.300 v15.6.0, section 4).

[0120] The NR user plane protocol stack (see, for example, 3GPP TS 38.300, section 4.4.1) includes the Packet Data Convergence Protocol (PDCP) (see section 6.4 of TS 38.300), Radio Link Control (RLC) (see section 6.3 of TS 38.300), and Medium Access Control (MAC) (see section 6.2 of TS 38.300) sublayers, which are terminated on the network side at the gNB. A new Access Stratum (AS) sublayer (Service Data Adaptation Protocol (SDAP)) is also introduced on top of PDCP (see, for example, 3GPP TS 38.300, section 6.5). A control plane protocol stack is also defined for NR (see, for example, TS 38.300, section 4.4.2). An overview of Layer 2 functions is given in section 6 of TS 38.300. The functions of the PDCP, RLC and MAC sublayers are listed in clauses 6.4, 6.3 and 6.2 of TS 38.300, respectively. The functions of the RRC layer are listed in clause 7 of TS 38.300.

[0121] For example, the Medium-Access-Control layer handles logical channel multiplexing and scheduling and scheduling-related functions, including handling various numerologies.

[0122] For example, the physical layer (PHY) is responsible for coding, PHY HARQ processing, modulation, multi-antenna processing, and mapping of signals to appropriate physical time-frequency resources. The physical layer also handles 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 particular transport channel, and each transport channel is mapped to a corresponding physical channel. For example, the physical channels include the PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel) as uplink physical channels, and the PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), and PBCH (Physical Broadcast Channel) as downlink physical channels.

[0123] NR use cases / deployment scenarios 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 rates, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps in downlink and 10 Gbps in uplink) and effective (user-experienced) data rates that are about three times higher than those offered by IMT-Advanced. On the other hand, for URLLC, more stringent requirements are imposed on ultra-low latency (0.5 ms for user plane latency in UL and DL, respectively) and high reliability (1-10-5 within 1 ms). Finally, mMTC may require preferably high connection density (1,000,000 devices / km2 in urban environments), wide coverage in adverse environments, and extremely long battery life (15 years) for low-cost devices.

[0124] Therefore, OFDM numerology (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 valid for other use cases. For example, low latency services may preferably require a shorter symbol length (and therefore a larger subcarrier spacing) and / or fewer symbols per scheduling interval (also called TTI) than mMTC services. Furthermore, deployment scenarios with large channel delay spreads may preferably require a longer CP length than scenarios with small delay spreads. Subcarrier spacing may be optimized accordingly to maintain similar CP overhead. NR may support one or more subcarrier spacing values. Correspondingly, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz... are currently considered. The symbol length Tu and subcarrier spacing Δf are directly related by the formula Δf=1 / Tu. Similar to LTE systems, the term "resource element" can be used to mean the smallest resource unit consisting of one subcarrier for the length of one OFDM / SC-FDMA symbol.

[0125] In the new radio system 5G-NR, for each numerology and each carrier, a resource grid of subcarriers and OFDM symbols is defined for the uplink and downlink, respectively. Each element of the resource grid is called a resource element and is specified based on a frequency index in the frequency domain and a symbol position in the time domain (see 3GPP TS 38.211 v15.6.0).

[0126] <Functional separation between NG-RAN and 5GC in 5G NR> Figure 16 shows the functional separation between NG-RAN and 5GC. The logical node of NG-RAN is gNB or ng-eNB. 5GC has logical nodes AMF, UPF, and SMF.

[0127] For example, the gNB and ng-eNB host the following main functions: - Radio Resource Management functions such as Radio Bearer Control, Radio Admission Control, Connection Mobility Control, dynamic allocation (scheduling) of resources to UEs in both uplink and downlink; - IP header compression, encryption, and integrity protection of data; - Selection of the AMF at UE attach time if routing to the AMF cannot be determined from information provided by the UE; - Routing of user plane data towards the UPF; - Routing of control plane information towards AMF; - Setting up and tearing down connections; - Scheduling and sending paging messages; - Scheduling and transmission of system broadcast information (AMF or Operation, Admission, Maintenance (OAM) origin); - Configuration of measurements and measurement reporting for mobility and scheduling; - Transport level packet marking in the uplink; - Session management; - Support for network slicing; - Management of QoS flows and their mapping to data radio bearers; - Support for UEs in RRC_INACTIVE state; - NAS message delivery function; - Sharing of radio access networks; - Dual connectivity; - Close cooperation between NR and E-UTRA.

[0128] The Access and Mobility Management Function (AMF) hosts the following main functions: - Ability to terminate Non-Access Stratum (NAS) signalling; - NAS signaling security; - Access Stratum (AS) security control; - 3GPP Core Network (CN) inter-node signalling for mobility between access networks; - Reachability to idle mode UEs (including control and execution of paging retransmissions); - Managing the registration area; - Support for intra-system and inter-system mobility; - Access authentication; - Access authorization including roaming privilege checks; - Mobility management control (subscription and policies); - Support for network slicing; - Select the Session Management Function (SMF).

[0129] Additionally, the User Plane Function (UPF) hosts the following main functions: - anchor points for intra-RAT mobility / inter-RAT mobility (if applicable); - External PDU (Protocol Data Unit) Session Points for interconnection with data networks; - Packet routing and forwarding; - Packet inspection and policy rule enforcement for the user plane part; - Traffic usage reporting; - uplink classifier to support routing of traffic flows to the data network; - Branching Point for supporting multi-homed PDU session; - 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.

[0130] 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.

[0131] <RRC connection setup and reconfiguration procedures> Figure 17 shows some of the interactions between the UE, gNB, and AMF (5GC entity) in the NAS part when the UE moves from RRC_IDLE to RRC_CONNECTED (see TS 38.300 v15.6.0).

[0132] RRC is a higher layer signaling (protocol) used for UE and gNB configuration. 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 with an INITIAL CONTEXT SETUP REQUEST. The gNB then activates AS security together with the UE. This is done by the gNB sending a SecurityModeCommand message to the UE, and the UE responding with a SecurityModeComplete message to the gNB. The gNB then reconfigures to set up Signaling Radio Bearer 2 (SRB2) and Data Radio Bearer (DRB) by sending an RRCReconfiguration message to the UE and receiving an RRCReconfigurationComplete from the UE. For signaling-only connections, the steps related to RRCReconfiguration are omitted since SRB2 and DRB are not set up. Finally, the gNB informs the AMF that the setup procedure is complete with an INITIAL CONTEXT SETUP RESPONSE.

[0133] Therefore, the present disclosure provides an entity (e.g., AMF, SMF, etc.) of a 5th Generation Core (5GC), comprising: a control circuit that operatively establishes a Next Generation (NG) connection with a gNodeB; and a transmitter that operatively transmits an initial context setup message to the gNodeB via the NG connection 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 configuration information element (IE) to the UE via the signaling radio bearer. Then, the UE transmits in uplink or receives in downlink based on the resource allocation configuration.

[0134] <IMT usage scenarios after 2020> Figure 18 shows some use cases for 5G NR. The 3rd generation partnership project new radio (3GPP NR) considers three use cases that were envisioned by IMT-2020 to support a wide variety of services and applications. The first phase of 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 support for eMBB. Figure 18 shows some examples of envisioned usage scenarios for IMT beyond 2020 (see e.g. ITU-R M.2083 Figure 2).

[0135] URLLC use cases have stringent requirements for performance such as throughput, latency, and availability. URLLC use cases are envisioned as one of the enabling technologies for future applications such as wireless control of industrial production or manufacturing processes, remote medical surgery, automation of power transmission and distribution in smart grids, and road safety. URLLC's ultra-high reliability is supported by identifying technologies that meet the requirements set by TR 38.913. Key requirements for NR URLLC in Release 15 include a target user plane latency of 0.5 ms on the UL (uplink) and 0.5 ms on the DL (downlink). The overall URLLC requirement for a single packet transmission is a block error rate (BLER) of 1E-5 for a packet size of 32 bytes with a user plane latency of 1 ms.

[0136] From a physical layer perspective, reliability can be improved in many possible ways. Current room for reliability improvement includes defining a separate CQI table for URLLC, more compact DCI formats, PDCCH repetition, etc. However, this room can be expanded to achieve ultra-high reliability as NR (with respect to the key requirements of NR URLLC) becomes more stable and more developed. Specific use cases for NR URLLC in Release 15 include augmented reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0137] Also, technology enhancements targeted by NR URLLC aim at improving latency and improving reliability. Technology enhancements for improving latency include configurable numerology, non-slot-based scheduling with flexible mapping, grant-free (configured grant) uplink, slot-level repetition in data channel, and pre-emption in downlink. Pre-emption means that a transmission with already allocated resources is stopped and the already allocated resources are used for other transmissions with lower latency / higher priority requirements that are requested later. Thus, a transmission that was already allowed is preempted 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 preempted by a transmission of service type B (eMBB, etc.). Technology enhancements for improving reliability include dedicated CQI / MCS tables for a target BLER of 1E-5.

[0138] The use case of mMTC (massive machine type communication) is characterized by a very large number of connected devices transmitting relatively small amounts of data that are typically not sensitive to delays. The devices are required to be low-cost and have a very long battery life. From an NR perspective, the use of very narrow bandwidth portions is one solution that allows UEs to save power and extend battery life.

[0139] As mentioned above, the scope of reliability improvement in NR is expected to be broader. One of the key requirements for all cases, e.g. for URLLC and mMTC, is high or ultra-high reliability. Several mechanisms can improve reliability from a radio perspective and a network perspective. In general, there are two to three key areas that can help improve reliability. These areas include compact control channel information, data channel / control channel repetition, and diversity with respect to frequency, time, and / or spatial domains. These areas are generally applicable to reliability improvement regardless of the specific communication scenario.

[0140] Further use cases with more stringent requirements are envisaged for NR URLLC, such as factory automation, transportation and power distribution, such as high reliability (up to 10-6 level of reliability), high availability, packet size up to 256 bytes, time synchronization up to a few μs (depending on the use case, the value can be 1 μs or a few μs depending on the frequency range and low latency in the order of 0.5 ms to 1 ms (e.g. 0.5 ms latency in the targeted user plane)).

[0141] Furthermore, for NR URLLC, several technical enhancements may be available 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. Additionally, 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).

[0142] <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.

[0143] 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) for the PDU session, e.g. as shown above with reference to Fig. 17. Additional DRBs for the QoS flows of that PDU session can be configured later (when it is up to the NG-RAN). The NG-RAN maps packets belonging to different PDU sessions to different DRBs. The NAS level packet filters in the UE and 5GC associate UL and DL packets with QoS flows, whereas the AS level mapping rules in the UE and NG-RAN associate UL and DL QoS flows with DRBs.

[0144] Figure 19 shows the non-roaming reference architecture for 5G NR (see TS 23.501 v16.1.0, section 4.23). An Application Function (AF) (e.g., an external application server hosting 5G services as illustrated in Figure 18) interacts with the 3GPP core network to provide services. For example, it may access a Network Exposure Function (NEF) to support applications that affect traffic routing, or it may interact with a policy framework for policy control (e.g., QoS control) (see Policy Control Function (PCF)). Based on the operator's deployment, an Application Function that is considered trusted by the operator may interact directly with the relevant Network Function. An Application Function that is not allowed by the operator to directly access a Network Function interacts with the relevant Network Function using an exposure framework for the outside world via the NEF.

[0145] Figure 19 further illustrates further 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-provided services, Internet access, or third-party services). All or part of the core network functions and application services may be deployed and run in a cloud computing environment.

[0146] Therefore, the present disclosure provides an application server (e.g., an AF in a 5G architecture) comprising: a transmitter that, when operated, sends a request including QoS requirements for at least one of a URLLC service, an eMMB service, and an mMTC service to at least one of the 5GC functions (e.g., NEF, AMF, SMF, PCF, UPF, etc.) to establish a PDU session including a radio bearer between a gNodeB and a UE according to the QoS requirements; and a control circuit that, when operated, performs a service using the established PDU session.

[0147] The present disclosure can be realized by software, hardware, or software in cooperation with hardware. Each functional block used in the description of the above embodiment may be realized partially or entirely as an LSI, which is an integrated circuit, and each process described in the above embodiment 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 some or all of the functional blocks. The LSI may have input and output of data. Depending on the degree of integration, the LSI may be called an IC, a system LSI, a super LSI, or an ultra LSI.

[0148] The method of integration is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, after LSI manufacturing, a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing.

[0149] Furthermore, if a new integrated circuit technology that can replace LSI appears due to the progress of semiconductor technology or a derivative technology, it is possible to integrate the functional blocks using that technology. The application of biotechnology is also a possibility.

[0150] The present disclosure may be implemented in any type of apparatus, device, or system having a communication function (collectively referred to as a communication apparatus). The communication apparatus may include a radio transceiver and processing / control circuitry. The radio transceiver may include a receiver and a transmitter, or both as functions. The radio transceiver (transmitter and receiver) may include a radio frequency (RF) 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 (e.g., cell phones, smartphones, etc.), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks, etc.), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices, etc.), game consoles, digital book readers, telehealth and telemedicine devices, communication-enabled vehicles or mobile conveyances (e.g., cars, airplanes, boats, etc.), and combinations of the above devices.

[0151] Communications Equipment includes, but is not limited to portable or mobile equipment, non-portable or fixed equipment, devices and systems of any kind, such as smart home devices (appliances, lighting equipment, smart meters or metering devices, control panels, etc.), vending machines and any other "Things" that may exist on an Internet of Things (IoT) network.

[0152] Communications include data communications via cellular systems, wireless LAN systems, communications satellite systems, etc., as well as data communications via combinations of these.

[0153] A communications apparatus also includes devices, such as controllers and sensors, connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications apparatus.

[0154] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these.

[0155] A terminal according to one embodiment of the present disclosure includes a receiving circuit that receives first information regarding a transmission instruction for some unit time intervals among a plurality of unit time intervals for a reference signal configured to be transmitted in the plurality of unit time intervals, and a control circuit that controls transmission of the reference signal based on the first information.

[0156] In one embodiment of the present disclosure, the receiving circuit receives second information including resource information for each of the plurality of unit time intervals, and the resource information corresponding to each of the some of the unit time intervals is assigned an identical value among multiple values ​​represented by bits of the first information.

[0157] In one embodiment of the present disclosure, the receiving circuit receives second information including resource information corresponding to each of the plurality of unit time intervals, and the resource information for each of the plurality of unit time intervals is associated with one of a plurality of values ​​represented by bits of the first information, and the number of values ​​associated with the resource information differs between the first unit time interval and the second unit time interval among the plurality of unit time intervals.

[0158] In one embodiment of the present disclosure, the reference signal is used for antenna switching in the plurality of unit time periods.

[0159] In an embodiment of the present disclosure, the control circuit determines an antenna port to be used for transmitting the reference signal in each of the some unit time intervals based on the association between each of the plurality of unit time intervals and an antenna port.

[0160] A base station according to one embodiment of the present disclosure includes a transmission circuit that transmits information regarding a transmission instruction for some unit time intervals among a plurality of unit time intervals for a reference signal configured for transmission by a terminal in the plurality of unit time intervals, and a control circuit that controls reception of the reference signal based on the information.

[0161] In a communication method relating to one embodiment of the present disclosure, a terminal receives information regarding a transmission instruction for some of a plurality of unit time intervals for a reference signal set to be transmitted in the plurality of unit time intervals, and controls the transmission of the reference signal based on the information.

[0162] In a communication method relating to one embodiment of the present disclosure, a base station transmits information regarding a transmission instruction for some unit time intervals among a plurality of unit time intervals for a reference signal that is set to be transmitted by a terminal in the plurality of unit time intervals, and controls reception of the reference signal based on the information.

[0163] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2020-121432, filed on July 15, 2020, are incorporated herein by reference in their entirety. [Industrial Applicability]

[0164] One embodiment of the present disclosure is useful in wireless communication systems. [Explanation of symbols]

[0165] 100 base stations 101,203 Control section 102 Encoding and modulation section 103,206 Transmission processing unit 104,207 Transmitter 105,201 Receiver 106,202 Receiving processing section 107 Data signal receiving unit 108 Reference signal receiver 200 terminals 204 Reference signal generation section 205 Data signal generator

Claims

1. a receiving circuit for receiving first information indicating a portion of a plurality of candidate unit time resources for transmitting a non-periodic reference signal and second information regarding each of the plurality of candidate unit time resources; a control circuit that controls allocation of time resources used for transmitting the reference signal based on the first information and the second information; Equipped with The second information is associated with any one of a plurality of values ​​represented by bits of the first information; the number of values ​​associated with information on a first candidate unit time resource and information on a second candidate unit time resource different from the first candidate unit time resource are different from each other among the plurality of candidate unit time resources; Terminal.

2. The information regarding each of the part of the candidate unit time resources is associated with the same value among a plurality of values ​​represented by bits of the first information. The terminal according to claim 1.

3. The control circuit switches an antenna port for transmitting the reference signal for each of the plurality of candidate unit time resources. The terminal according to claim 1.

4. the control circuit determines an antenna port to be used for transmitting the reference signal in each of the part of the candidate unit time resources based on an association between each of the plurality of candidate unit time resources and an antenna port. The terminal according to claim 1.

5. the control circuit does not change the association when dropping the reference signal in at least one candidate unit time resource among the plurality of candidate unit time resources. The terminal according to claim 4.

6. a transmission circuit configured to transmit first information indicating a portion of a plurality of candidate unit time resources for a terminal to transmit a non-periodic reference signal and second information regarding each of the plurality of candidate unit time resources; a control circuit that controls allocation of time resources used for receiving the reference signal based on the first information and the second information; Equipped with The second information is associated with any one of a plurality of values ​​represented by bits of the first information; the number of values ​​associated with information on a first candidate unit time resource and information on a second candidate unit time resource different from the first candidate unit time resource are different from each other among the plurality of candidate unit time resources; Base station.

7. The terminal is receiving first information indicating a portion of a plurality of candidate unit time resources for transmitting a non-periodic reference signal and second information regarding each of the plurality of candidate unit time resources; Controlling allocation of time resources used for transmitting the reference signal based on the first information and the second information; The second information is associated with any one of a plurality of values ​​represented by bits of the first information; the number of values ​​associated with information on a first candidate unit time resource and information on a second candidate unit time resource different from the first candidate unit time resource are different from each other among the plurality of candidate unit time resources; Communication methods.

8. The base station is Transmitting first information indicating a portion of a plurality of candidate unit time resources for transmitting a non-periodic reference signal by a terminal and second information regarding each of the plurality of candidate unit time resources; Controlling allocation of time resources used for receiving the reference signal based on the first information and the second information; The second information is associated with any one of a plurality of values ​​represented by bits of the first information; the number of values ​​associated with information on a first candidate unit time resource and information on a second candidate unit time resource different from the first candidate unit time resource are different from each other among the plurality of candidate unit time resources; Communication methods.

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