Terminals, base stations, and communication methods

Abstract

A terminal is provided with a control circuit for setting a reception frequency resource of a second control signal received after receiving a first control signal in a first frequency resource to a second frequency resource including a frequency resource different from the first frequency resource, and a receiving circuit for receiving a second control signal in the second frequency resource.

Description

Technical Field

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

Background Art

[0002] A communication system called the 5th generation mobile communication system (5G) is under consideration. In the 3rd Generation Partnership Project (3GPP), which is an international standardization organization, the enhancement of the LTE / LTE-Advanced system and a new method called New Radio Access Technology (also called New RAT or NR), which is not necessarily backward compatible with the LTE / LTE-Advanced system (see, for example, Non-Patent Document 1), are being considered for the enhancement of the 5G communication system.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

[0004] However, there is room for consideration regarding a method for improving the utilization efficiency of time resources in a terminal.

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

[0006] A terminal according to one embodiment of the present disclosure comprises a control circuit that sets the receiving frequency resource for a second control signal received after receiving a first control signal in a first frequency resource to a second frequency resource that includes a frequency resource different from the first frequency resource, and a receiving circuit that receives the second control signal in the second frequency resource.

[0007] These comprehensive or specific embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or recording media, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media.

[0008] According to one embodiment of this disclosure, the efficiency of time resource utilization in a terminal can be improved.

[0009] Further advantages and effects of one embodiment of this disclosure will be made apparent from the specification and drawings. Such advantages and / or effects are provided by several embodiments and features described in the specification and drawings, but not all of them are necessarily provided in order to obtain one or more identical features. [Brief explanation of the drawing]

[0010] [Figure 1] A diagram showing an example of frequency switching. [Figure 2] Block diagram showing some example configurations of base stations. [Figure 3] Block diagram showing some example configurations of the terminal. [Figure 4] Block diagram showing an example of a base station configuration. [Figure 5] Block diagram showing an example of terminal configuration [Figure 6] Sequence diagram showing an example of operation of the base station and terminal related to Operation Example 1. [Figure 7] A diagram showing an example of frequency switching related to Operation Example 1. [Figure 8] Sequence diagram showing the operation example of the base station and terminal related to Operation Example 2. [Figure 9] A diagram showing an example of frequency switching related to Operation Example 2. [Figure 10] Diagram showing other examples of frequency switching. [Figure 11] Diagram showing other examples of frequency switching. [Figure 12] Diagram of a representative architecture of a 3GPP NR system [Figure 13] Schematic diagram showing the functional separation between NG-RAN and 5GC. [Figure 14] Sequence diagram of the setup / reconfiguration procedure for Radio Resource Control (RRC) connection. [Figure 15] This schematic diagram illustrates usage scenarios for high-capacity, high-speed communication (eMBB: enhanced Mobile Broadband), massive machine type communications (mMTC: massive machine type communications), and highly reliable, ultra-low-latency communications (URLLC: Ultra Reliable and Low Latency Communications). [Figure 16] Block diagram illustrating an exemplary 5G system architecture for a non-roaming scenario. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described in detail below with reference to the drawings.

[0012] In the following description, for example, a wireless frame, a slot, and a symbol are each a unit of a physical resource in the time domain. For example, the length of one frame may be 10 milliseconds. For example, one frame may be composed of a plurality (e.g., 10, 20, or other values) of slots. Also, for example, depending on the slot length, the number of slots constituting one frame may be variable. Also, one slot may be composed of, for example, a plurality (e.g., 14 or 12) of symbols. For example, one symbol is the smallest physical resource unit in the time domain, and the symbol length may vary depending on the subcarrier spacing (SCS).

[0013] Also, a subcarrier and a resource block (RB) are each a unit of a physical resource in the frequency domain. For example, one resource block may be composed of 12 subcarriers. For example, one subcarrier may be the smallest physical resource unit in the frequency domain. The subcarrier spacing is variable and may be, for example, 15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz, or other values.

[0014] [Regarding Bandwidth Part (BWP)] In NR, for example, one or more BWPs (e.g., bandwidth parts) may be set for a terminal (e.g., also referred to as a mobile station or User Equipment (UE)). For example, one or more of the plurality of BWPs set for the terminal may be activated. The terminal may transmit and receive a wireless signal according to the parameters set for the BWP activated at a certain time.

[0015] The parameters for setting the BWP may include, for example, at least one of frequency position, bandwidth, SCS (subcarrier spacing), CORESET, and TCI state. For example, when a plurality of BWPs are set for a terminal, different values may be set individually for each BWP with respect to the above-described parameters of the BWP.

[0016] Note that CORESET is, for example, a parameter indicating a resource where a downlink control channel (e.g., Physical Downlink Control Channel (PDCCH)) is transmitted. For example, one or more CORESETs may be set per BWP. For example, one of the plurality of CORESETs set for the BWP may be used during transmission and reception. Also, the bandwidth of the CORESET may be set, for example, to be less than or equal to the bandwidth supported by the terminal.

[0017] Also, TCI state is, for example, a parameter that can be set to one or more per BWP. For example, one of the plurality of TCI states set for the BWP may be used during transmission and reception. Here, for example, for transmission and reception where the TCI state is common, the propagation path characteristics may be considered to be similar (in other words, Quasi-Colocation (QCL)).

[0018] [Regarding Reduced Capability NR Devices] In Release 17 (hereinafter referred to as Rel-17 NR), for example, compared with Release 15 or 16 (hereinafter referred to as Rel-15 / 16 NR) (e.g., the initial release of NR), specifications (e.g., Reduced Capability (RedCap)) are expected to be formulated to reduce power consumption or cost by restricting some functions or performance and to realize terminals (e.g., NR terminals) that support various use cases (see, for example, Non-Patent Document 2).

[0019] These devices are sometimes referred to as Reduced Capability NR Devices, RedCap, RedCap devices, NR-Lite, or NR-Light.

[0020] To reduce power consumption or costs, for example, reducing the computational load on the terminal is considered. One way to reduce the computational load on the terminal is to set the bandwidth supported by the terminal to be narrower than the bandwidth supported by existing terminals. For example, the maximum frequency bandwidth supported by the terminal may be 20 MHz or 40 MHz in FR1 (Frequency range 1) and 50 MHz or 100 MHz in FR2 (Frequency range 2).

[0021] For RedCap terminals, a BWP (Bandwidth Programming) occupying a wider bandwidth than the bandwidth supported by the terminal may be assigned. For example, a RedCap terminal supporting 20MHz may be assigned a BWP occupying an 80MHz bandwidth. In this case, the base station (also known as a gNB) can assign a signal to any frequency resource within the 80MHz BWP. On the other hand, the frequency resources that a RedCap terminal can simultaneously transmit and receive are any 20MHz within the 80MHz BWP. For example, if a terminal needs to transmit or receive on a different frequency resource than the 20MHz resource it is currently using, the terminal will perform a frequency switch at the receiver. During the frequency switch at the receiver, the terminal may be unable to transmit or receive signals.

[0022] Figure 1 shows an example of switching the receiving frequency in a terminal.

[0023] For example, a base station places a first PDCCH on a certain frequency resource (e.g., a 20MHz frequency resource) based on a CORESET within the BWP (e.g., a bandwidth wider than 20MHz) assigned to a terminal. At this time, the data channel (e.g., Physical Downlink Shared Channel (PDSCH)) assigned by the first PDCCH may be placed on a different frequency resource than the frequency resource of the first PDCCH. For example, as shown in Figure 1, if the frequency resource of the PDSCH is outside the frequency range that the terminal can receive when receiving the first PDCCH, the terminal switches its receiving frequency after receiving the first PDCCH in order to receive the PDSCH (e.g., this is called Radio Frequency (RF) retuning). Also, as shown in Figure 1, after receiving the PDSCH, the terminal switches its receiving frequency again based on the CORESET in order to receive the second PDCCH.

[0024] During frequency switching in such terminals, no signals are transmitted or received, resulting in periods of no transmission, which reduces the efficiency of resource utilization (e.g., time resources).

[0025] Therefore, in one embodiment of this disclosure, a method for improving resource utilization efficiency in a terminal to which RedCap is applied will be described.

[0026] For example, in one embodiment of the present disclosure, a terminal (e.g., a RedCap terminal) may receive a second control signal (e.g., PDCCH) on a different frequency resource than the first control signal (e.g., PDCCH) after receiving a data signal (e.g., PDSCH) assigned by a first control signal (e.g., PDCCH). In one embodiment of the present disclosure, this reduces the frequency switching time (or number of frequency switching cycles) in the terminal and improves the efficiency of time resource utilization.

[0027] In the following explanation, for example, "first control signal (or first PDCCH)" may refer to a control signal (e.g., PDCCH) received by the terminal before the terminal's frequency switching. Also, "second control signal (or second PDCCH)" may refer to a control signal (e.g., PDCCH) received by the terminal after the terminal's frequency switching. For example, the second PDCCH may also be a control signal received by the terminal after the data signal (e.g., PDSCH) assigned by the first PDCCH.

[0028] [Overview of the communication system] The communication system according to this embodiment includes a base station 100 and a terminal 200.

[0029] Figure 2 is a block diagram showing a partial configuration example of a base station 100 according to this embodiment. In the base station 100 shown in Figure 2, the control unit 101 (corresponding to a control circuit, for example) sets the frequency resource of the second control signal received by the terminal 200 after it has received the first control signal in the first frequency resource to a second frequency resource that includes a different frequency resource from the first frequency resource. The transmitting unit 106 (corresponding to a transmitting circuit, for example) transmits the second control signal in the second frequency resource.

[0030] Figure 3 is a block diagram showing a partial configuration example of the terminal 200 according to this embodiment. In the terminal 200 shown in Figure 3, the control unit 206 (corresponding to a control circuit, for example) sets the receiving frequency resource for the second control signal (e.g., second PDCCH) to be received after receiving the first control signal (e.g., first PDCCH) in the first frequency resource to a second frequency resource that includes a different frequency resource from the first frequency resource. The receiving unit 202 (corresponding to a receiving circuit, for example) receives the second control signal in the second frequency resource.

[0031] [Base station configuration] Figure 4 is a block diagram showing an example configuration of a base station 100 according to this embodiment. In Figure 4, the base station 100 includes a control unit 101, a DCI (Downlink Control Information) generation unit 102, a higher layer signal generation unit 103, an encoding / modulation unit 104, a signal arrangement unit 105, a transmission unit 106, an antenna 107, a receiving unit 108, and a demodulation / decoding unit 109.

[0032] The control unit 101 may, for example, determine parameters related to the BWP to be set on the terminal 200. The control unit 101 may also determine, for example, at least one of the resources of multiple subbands obtained by dividing the BWP, the resources of the control channel (e.g., PDCCH), and the resources of the data channel (e.g., PDSCH). Based on the determined parameters, the control unit 101 may instruct the DCI generation unit 102 to generate downlink control information (e.g., DCI), or instruct the upper layer signal generation unit 103 to generate upper layer signals (e.g., upper layer parameters or upper layer signaling).

[0033] The DCI generation unit 102 may, for example, generate DCI based on instructions from the control unit 101 and output the generated DCI to the signal arrangement unit 105.

[0034] The upper layer signal generation unit 103 may, for example, generate an upper layer signal based on instructions from the control unit 101 and output the generated upper layer signal to the encoding / modulation unit 104.

[0035] The encoding and modulation unit 104 may, for example, error-corrected encode and modulate the downlink data (e.g., PDSCH) and the upper layer signal input from the upper layer signal generation unit 103, and output the modulated signal to the signal arrangement unit 105.

[0036] The signal placement unit 105 may, for example, place the DCI input from the DCI generation unit 102 and the signals input from the encoding / modulation unit 104 into resources. For example, the signal placement unit 105 may place the signals input from the encoding / modulation unit 104 into a PDSCH resource and the DCI into a PDCCH resource. The signal placement unit 105 outputs the signals placed into each resource to the transmission unit 106.

[0037] The transmitting unit 106 performs wireless transmission processing, including frequency conversion using a carrier wave (e.g., upconversion), on the signal input from the signal arrangement unit 105, and outputs the signal after wireless transmission processing to the antenna 107.

[0038] Antenna 107 radiates, for example, a signal input from the transmitter 106 (for example, a downlink signal) toward the terminal 200. Antenna 107 also receives, for example, an uplink signal transmitted from the terminal 200 and outputs it to the receiver 108.

[0039] The uplink signal may be, for example, a signal from an uplink data channel (e.g., Physical Uplink Shared Channel (PUSCH)), an uplink control channel (e.g., Physical Uplink Control Channel (PUCCH)), or a random access channel (e.g., Physical Random Access Channel (PRACH)).

[0040] The receiving unit 108 performs wireless reception processing, including frequency conversion (e.g., down-conversion), on the signal input from the antenna 107, and outputs the processed signal to the demodulation / decoding unit 109.

[0041] The demodulation / decoding unit 109 demodulates and decodes the signal input from the receiving unit 108, for example, and outputs an uplink signal.

[0042] [Device Configuration] Figure 5 is a block diagram showing an example configuration of terminal 200 according to this embodiment.

[0043] In Figure 5, the terminal 200 includes an antenna 201, a receiving unit 202, a signal separation unit 203, a DCI detection unit 204, a demodulation / decoding unit 205, a control unit 206, an encoding / modulation unit 207, and a transmitting unit 208.

[0044] Antenna 201, for example, receives downlink signals transmitted by base station 100 and outputs them to receiving unit 202. Antenna 201 also radiates uplink signals input from transmitting unit 208 to base station 100.

[0045] The receiving unit 202 performs wireless reception processing, including frequency conversion (e.g., down-conversion), on the signal input from the antenna 201, and outputs the processed signal to the signal separation unit 203. For example, the receiving unit 202 may switch the receiving frequency according to a frequency switching instruction input from the control unit 206. For example, the receiving unit 202 may adjust the receiving frequency to enable reception of a data channel (e.g., PDSCH) by switching the receiving frequency.

[0046] The signal separation unit 203 may identify the resources for each channel or signal based, for example, on pre-defined or pre-configured information and at least one of resource-related instructions input from the control unit 206. The signal separation unit 203 extracts (in other words, separates) the signals placed on the identified PDCCH resources and outputs them to the DCI detection unit 204. The signal separation unit 203 also outputs the signals placed on the identified PDSCH resources to the demodulation / decoding unit 205.

[0047] The DCI detection unit 204 may, for example, detect DCI from the signal input from the signal separation unit 203 (for example, the signal on the PDCCH resource). The DCI detection unit 204 may, for example, output the detected DCI to the control unit 206.

[0048] The demodulation / decoding unit 205 demodulates and error-corrects the signal input from the signal separation unit 203 (for example, a signal on the PDSCH resource) to obtain at least one of the downlink data and the upper layer signal. The demodulation / decoding unit 205 may output the upper layer signal obtained by decoding to the control unit 206.

[0049] The control unit 206 may, for example, identify a PDSCH resource based on the DCI input from the DCI detection unit 204 and output (in other words, instruct) information regarding the identified PDSCH resource to the signal separation unit 203. For example, if the frequency resource of the PDSCH is outside the range of frequency resources currently receivable by the receiving unit 202, the control unit 206 may output (in other words, instruct) information regarding frequency switching to the receiving unit 202.

[0050] Furthermore, the control unit 206 may, for example, identify the BWP parameters or subband resources to be set in the terminal 200 based on the DCI input from the DCI detection unit 204 and at least one of the upper layer signals input from the demodulation / decoding unit 205, and set the BWP or subband.

[0051] The encoding and modulation unit 207 may, for example, encode and modulate the uplink signal (e.g., PUSCH, PUCCH, or PRACH) and output the modulated signal to the transmission unit 208.

[0052] The transmitting unit 208 performs wireless transmission processing, including frequency conversion (e.g., upconversion), on the signal input from the encoding / modulation unit 207, and outputs the signal after wireless transmission processing to the antenna 201.

[0053] [Example of operation of base station 100 and terminal 200] Next, we will describe an example of the operation of the base station 100 and terminal 200 mentioned above.

[0054] <Example of operation 1> In example 1, for instance, the base station 100 and the terminal 200 may determine the receiving frequency resource for the second control signal based on the frequency resource to which the data signal allocated by the first control signal is allocated.

[0055] Figure 6 is a sequence diagram showing an example of processing at the base station 100 and terminal 200.

[0056] (S101) The base station 100 may, for example, determine the values ​​of one or more parameters related to the BWP to be assigned to the terminal 200. The parameters related to the BWP may include, for example, at least the BWP bandwidth. The BWP bandwidth may be, for example, wider than the bandwidth supported by the terminal 200. The bandwidth supported by the terminal 200 may be reported to the base station 100 in advance by the terminal 200.

[0057] For example, base station 100 may assign a BWP with a bandwidth of "80 MHz" to terminal 200 that has previously reported that its supported bandwidth is "20 MHz". Note that the bandwidth supported by terminal 200 and the bandwidth of the BWP are not limited to these values ​​and may be other values. Also, the BWP may be set to a bandwidth less than or equal to the bandwidth supported by terminal 200.

[0058] The base station 100 may transmit a control signal to the terminal 200 that includes information about the determined BWP parameters. The control signal may also include information about an instruction to activate a BWP (for example, a BWP that occupies a wider bandwidth than the bandwidth supported by the terminal 200).

[0059] Terminal 200 may, for example, receive a control signal from base station 100, identify the BWP parameters based on the received control signal, and configure the BWP based on the identified parameters. Alternatively, terminal 200 may, for example, activate a BWP (for example, a BWP that occupies a wider bandwidth than the bandwidth supported by terminal 200) based on the control signal from base station 100.

[0060] (S102) The base station 100 may, for example, place a DCI on the first PDCCH and transmit the first PDCCH. The DCI may include, for example, PDSCH allocation information. For example, the base station 100 may allocate the PDSCH frequency resource outside the range of frequencies that the terminal 200 can receive when receiving the first PDCCH (for example, the frequency resource used to transmit the first PDCCH).

[0061] Terminal 200 may, for example, receive a first PDCCH transmitted from base station 100 and acquire (or extract, detect) the DCI contained in the first PDCCH.

[0062] The base station 100 and terminal 200 may determine or identify the frequency resources of the PDCCH based, for example, on the CORESET associated with the BWP. Alternatively, the base station 100 and terminal 200 may determine or identify the frequency resources of the PDCCH based, for example, on a signal (e.g., PDCCH or PDSCH) transmitted at a time prior to the transmission time of the first PDCCH.

[0063] (S103) For example, if the frequency resource of the PDSCH allocated by DCI is outside the range of receivable frequency resources at the time of receiving the first PDCCH, terminal 200 may switch the frequency of the receiving unit 202 of terminal 200.

[0064] For example, if the PDSCH frequency resource is included within the active BWP, terminal 200 does not need to switch the active BWP. In other words, if the PDSCH frequency resource is included within the active BWP, terminal 200 may switch the receiver frequency without switching the BWP.

[0065] (S104) The base station 100 may, for example, place a signal on the PDSCH based on the PDSCH allocation information and transmit the PDSCH. The terminal 200 may, for example, receive a signal on the PDSCH based on the PDSCH allocation information.

[0066] (S105) The base station 100 may, for example, determine the frequency resources of a second PDCCH. For example, the base station 100 may determine the frequency resources of a second PDCCH to be transmitted after the first PDCCH based on the frequency resources of the PDSCH allocated by the first PDCCH. For example, the base station 100 may determine the second PDCCH frequency resource to be any of the frequency resources within the frequency range that the terminal 200 can receive when receiving the PDSCH. For example, the frequency resources of the second PDCCH may be different from the frequency resources of the first PDCCH.

[0067] (S106) Terminal 200 may identify (or determine) the frequency resources of the second PDCCH, for example, in the same manner as the base station 100 in S105. For example, terminal 200 may determine the frequency resources of the second PDCCH to be received after the first PDCCH based on the frequency resources of the PDSCH allocated by the first PDCCH.

[0068] Figure 7 shows an example of frequency switching of the receiving unit 202 in terminal 200.

[0069] In Figure 7, for example, base station 100 places the first PDCCH in a frequency resource (e.g., a 20MHz frequency resource) within the BWP (e.g., a bandwidth wider than 20MHz) allocated to terminal 200. Also in Figure 7, base station 100 places the PDSCH allocated by the first PDCCH in a different frequency resource than the frequency resource of the first PDCCH.

[0070] In this case, as shown in Figure 7, terminal 200, for example, after receiving the first PDCCH, switches the frequency of its receiving unit 202 to receive the PDSCH (for example, RF retuning).

[0071] Furthermore, in the processes S105 and S106 of Figure 6, the base station 100 and the terminal 200 may determine or identify the frequency resources (e.g., frequency location) of the second PDCCH based on the frequency resources (or frequency location) of the PDSCH.

[0072] For example, the base station 100 and terminal 200 may set the center frequency of the PDSCH's frequency resources (e.g., the central resource block (RB)) to be the same as the center frequency of the second PDCCH's frequency resources (e.g., the central RB). Note that the frequency position (e.g., reference) used to determine the frequency resources of the second PDCCH is not limited to the central RB, but may be the minimum, middle, or maximum value among the indices of the RB or subcarriers occupied by the PDSCH.

[0073] Alternatively, the base station 100 and terminal 200 may determine or identify the frequency position of the second PDCCH based on the frequency position obtained by shifting the CORESET associated with the BWP in the frequency direction. Alternatively, the base station 100 and terminal 200 may determine or identify the frequency position of the second PDCCH based on the frequency position obtained by shifting the frequency position of the first PDCCH. For example, the base station 100 and terminal 200 may determine the frequency position of the second PDCCH based on the frequency resources of the PDSCH as described above, and determine the settings in the second PDCCH (parameters different from the frequency position, such as aggregation level) based on the CORESET associated with the BWP or the settings in the first PDCCH.

[0074] Alternatively, the frequency resource of the second PDCCH may be determined, for example, by the base station 100, and information regarding the determined frequency resource may be notified to the terminal 200 in advance by a control signal.

[0075] (S107) In Figure 6, the base station 100 may, for example, place a DCI in a second PDCCH and transmit the second PDCCH based on the determined frequency resource. The terminal 200 may, for example, receive the second PDCCH transmitted from the base station 100 based on the identified frequency resource and acquire (or extract, detect) the DCI contained in the second PDCCH.

[0076] For example, as shown in Figure 7, terminal 200 may receive a second PDCCH within the range of the frequency resource that received the PDSCH. In other words, terminal 200 may receive a second PDCCH without switching to the frequency on which the PDSCH was received.

[0077] Thus, in Operation Example 1, terminal 200 does not need to switch the frequency of the receiving unit 202 between receiving the first PDSCH and receiving the second PDCCH. Therefore, according to Operation Example 1, the number of frequency switches of the receiving unit 202 in terminal 200 can be reduced, thereby reducing the non-transmission period that occurs due to the frequency switching of the receiving unit 202 and improving the efficiency of time resource utilization.

[0078] Furthermore, in Operation Example 1, for example, terminal 200 can identify the frequency resources of the second PDCCH based on the frequency resources of the PDSCH, thereby suppressing the notification of control signals related to the frequency resources of the second PDCCH and reducing the overhead of control signals.

[0079] <Example of operation 2> In example 2, for instance, the BWP may be divided into multiple subbands, and control signals may be transmitted and received in at least two of these subbands (for example, the first subband and the second subband).

[0080] Figure 8 is a sequence diagram showing an example of processing at the base station 100 and terminal 200.

[0081] (S201) The base station 100 may, for example, determine the values ​​of one or more parameters related to the BWP to be assigned to the terminal 200. The parameters related to the BWP may include, for example, at least the BWP bandwidth. The BWP bandwidth may be, for example, wider than the bandwidth supported by the terminal 200. The bandwidth supported by the terminal 200 may be reported to the base station 100 in advance by the terminal 200.

[0082] For example, base station 100 may assign a BWP with a bandwidth of "80 MHz" to terminal 200 that has previously reported that its supported bandwidth is "20 MHz". Note that the bandwidth supported by terminal 200 and the bandwidth of the BWP are not limited to these values ​​and may be other values. Also, the BWP may be set to a bandwidth less than or equal to the bandwidth supported by terminal 200.

[0083] Furthermore, the base station 100 may determine, for example, multiple subbands related to the BWP to be allocated to the terminal 200. Here, the frequency resources of each subband may, for example, be located inside the BWP (in other words, they do not have to be located outside the BWP). Also, the bandwidth of each subband may be, for example, less than or equal to the bandwidth supported by the terminal 200. Also, for example, the bandwidths between multiple subbands may be common or different.

[0084] Figure 9 shows an example of the BWP and subbands set for terminal 200. In Figure 9, for example, base station 100 sets at least a first subband (sub-band #1) and a second subband (sub-band #2) within the BWP (e.g., a bandwidth wider than 20 MHz) allocated to terminal 200.

[0085] (S202) The base station 100 may transmit a control signal to the terminal 200 that includes information about the determined BWP parameters. The control signal may also include information about an instruction to activate a BWP (for example, a BWP that occupies a wider bandwidth than the bandwidth supported by the terminal 200). The control signal may also include information about subbands.

[0086] Terminal 200 receives, for example, a control signal from base station 100.

[0087] (S203) Terminal 200 may, for example, identify the BWP parameters based on the received control signal and set the BWP based on the identified parameters. Alternatively, terminal 200 may, for example, identify the settings for the subbands into which the BWP is divided based on the received control signal.

[0088] Furthermore, terminal 200 may, for example, activate a BWP (for example, a BWP that occupies a wider bandwidth than the bandwidth supported by terminal 200) based on the received control signal.

[0089] (S204) The base station 100 may, for example, place a DCI in the first PDCCH and transmit the first PDCCH. For example, the base station 100 may set up the first PDCCH resource in a first subband and a second subband among a plurality of subbands. For example, the first subband may be a resource within the range of frequencies that the terminal 200 can currently receive, and the second subband may be a resource outside the range of frequencies that the terminal can currently receive.

[0090] Furthermore, the DCI placed in the first PDCCH may include, for example, PDSCH allocation information. The resources to which the PDSCH is allocated may be, for example, resources within the second subband.

[0091] Terminal 200 may, for example, receive a first PDCCH transmitted from base station 100 and acquire (or extract, detect) the DCI contained in the first PDCCH. In the example shown in Figure 9, terminal 200 receives the first PDCCH in, for example, a first subband.

[0092] (S205) Terminal 200 may switch the frequency of its receiver 202 if, for example, the frequency resource of the PDSCH allocated by DCI is outside the range of frequency resources that terminal 200 can receive at the time of receiving the first PDCCH. In the example shown in Figure 9, terminal 200, for example, after receiving the first PDCCH in the first subband, switches the frequency of its receiver 202 from the first subband to the second subband in order to receive the PDSCH (for example, RF retuning).

[0093] For example, if the PDSCH frequency resource is included within the active BWP, terminal 200 does not need to switch the active BWP. In other words, if the PDSCH frequency resource is included within the active BWP, terminal 200 may switch the receiver frequency without switching the BWP.

[0094] Furthermore, terminal 200 does not need to perform frequency switching if, for example, it fails to receive the first PDCCH.

[0095] (S206) The base station 100 may, for example, place a signal on the PDSCH based on the PDSCH allocation information and transmit the PDSCH. The terminal 200 may, for example, receive a signal on the PDSCH based on the PDSCH allocation information.

[0096] (S207) The base station 100 may, for example, place a DCI in the second PDCCH and transmit the second PDCCH. For example, the base station 100 may set up the second PDCCH resource in the first subband and the second subband among multiple subbands.

[0097] Terminal 200 may receive the second PDCCH transmitted from base station 100 in either the first subband or the second subband among several subbands. For example, if terminal 200 performs frequency switching (for example, switching from the first subband to the second subband) in processing S205, it may receive the second PDCCH in the second subband. On the other hand, if terminal 200 does not perform frequency switching (for example, switching from the first subband to the second subband) in processing S205, it may receive the second PDCCH in the first subband.

[0098] In the example shown in Figure 9, terminal 200 performs frequency switching (RF retuning) from the first subband to the second subband when receiving the PDSCH, and receives the second PDCCH in the second subband after the switch.

[0099] Thus, in Operation Example 2, since the PDCCH is mapped to multiple subbands within the BWP, terminal 200 can receive the PDCCH in a subband within the frequency range that terminal 200 can receive, regardless of whether or not frequency switching occurs. Therefore, for example, after receiving a PDSCH, terminal 200 can receive a second PDCCH in a subband within the same frequency range as the resource of the PDSCH, thus eliminating the need to switch the frequency of the receiving unit 202 until the second PDCCH is received. Thus, according to Operation Example 2, the number of frequency switches of the receiving unit 202 in terminal 200 can be reduced, thereby reducing the non-transmission period that occurs due to frequency switching of the receiving unit 202 and improving the efficiency of time resource utilization.

[0100] Furthermore, in Operation Example 2, for example, if terminal 200 fails to receive the first PDCCH in the first subband and the second subband, it may decide to receive the second PDCCH in the subband corresponding to the allocated bandwidth of the first PDCCH, and if it succeeds in receiving the first PDCCH, it may decide to receive the second PDCCH in a subband different from the subband corresponding to the allocated bandwidth of the first PDCCH. With this reception control, terminal 200 can receive the second PDCCH in the reception bandwidth of the first PDCCH, even if it fails to receive the first PDCCH. Therefore, according to Operation Example 2, for example, compared to Operation Example 1, terminal 200 is more likely to receive the control signal, thus enabling more stable operation.

[0101] In operation example 2, the PDCCHs set in multiple subbands may be channels obtained by shifting the frequency domain of a PDCCH placed in one of the subbands. Also, the information contained in the DCIs placed in each of the multiple subband PDCCHs may be the same or different between the subbands.

[0102] Furthermore, in Operation Example 2, the frequency resources occupied by the subbands may be set so as not to overlap with each other. This suppresses collisions between PDCCHs in each subband and reduces the probability of PDCCH decoding failure at terminal 200 (in other words, it improves the probability of successful PDCCH decoding).

[0103] Furthermore, while Operation Example 2 described the case where PDSCH is transmitted on one subband, it is not limited to this, and PDSCH may be transmitted on multiple subbands.

[0104] Furthermore, while Operation Example 2 described a case where the first PDCCH is assigned to multiple subbands as an example, it is not limited to this. The frequency resource to which the first PDCCH is assigned may be set to at least one of the multiple subbands (for example, the first subband in Figure 9), and the frequency resource to which the second PDCCH is assigned may be set to multiple subbands (for example, the first subband and the second subband).

[0105] Furthermore, in Operation Example 2, the resources (e.g., subbands) to which the first PDCCH and the second PDCCH are mapped may differ periodically.

[0106] Furthermore, the number of subbands described in Operation Example 2 is just an example and is not limited to that. Also, a PDCCH (for example, at least one of the first and second PDCCHs) may be mapped to some of the subbands among the multiple subbands set up on terminal 200, and not necessarily to the remaining subbands. Alternatively, a PDCCH (for example, at least one of the first and second PDCCHs) may be mapped to all of the set up subbands.

[0107] The above describes examples of the operation of the base station 100 and terminal 200.

[0108] As described above, in this embodiment, the base station 100 and the terminal 200 set the receiving frequency resource for the second PDCCH that the terminal 200 receives after receiving the first PDCCH in the first frequency resource to a second frequency resource that includes a different frequency resource from the first frequency resource. For example, in operation example 1, the frequency resource for the second PDCCH may be set based on the frequency resource to which the data signal is assigned. Also, for example, in operation example 2, the frequency resource for the second PDCCH may be set to multiple subbands.

[0109] As a result, terminal 200 can receive, for example, the first PDCCH and the second PDCCH on different frequency resources. Therefore, for example, terminal 200 is less likely to have to perform frequency switching (RF retuning) to receive the second PDCCH after receiving the data signal assigned by the first PDCCH. Thus, according to this embodiment, terminal 200 can reduce the number of frequency switching (RF retuning) operations of the receiving unit 202, thereby suppressing the occurrence of non-transmission periods due to frequency switching and improving the efficiency of time resource utilization.

[0110] The embodiments of this disclosure have been described above.

[0111] [Other embodiments] (Combination of Operation Example 1 and Operation Example 2) Operation Example 1 and Operation Example 2 may be combined. For example, the base station 100 and terminal 200 may, for some frequency resources within the BWP set for terminal 200, set the receiving frequency resource of the second PDCCH based on the frequency resource of the PDSCH allocated by the first PDCCH, as in Operation Example 1. Alternatively, for other frequency resources within the BWP set for terminal 200, the base station 100 and terminal 200 may, as in Operation Example 2, set the frequency resources of the PDCCH (e.g., the first PDCCH and the second PDCCH) in multiple subbands.

[0112] By combining Operation Example 1 and Operation Example 2, the flexibility of PDCCH and PDSCH assignment in BWP can be improved.

[0113] (Conflict between PDCCH and PDSCH) In the above embodiment, as shown in Figures 10 and 11, the base station 100 may, for example, assign the PDSCH allocated by the first PDCCH to the second PDCCH at the same time (or the same transmission / reception timing). Figure 10 shows an example where the frequency resource to which the first PDCCH is mapped and the frequency resource to which the second PDCCH is mapped are the same, and Figure 11 shows an example where the frequency resource to which the first PDCCH is mapped and the frequency resource to which the second PDCCH is mapped are different.

[0114] In this case, terminal 200 may be able to receive either the second PDCCH or the PDSCH. For example, terminal 200 may decide to switch the receiving frequency from the frequency resource that received the first PDCCH to either the frequency resource allocated to the second PDCCH or the frequency resource allocated to the PDSCH.

[0115] For example, in Figure 10, terminal 200 may decide which signal to receive (in other words, which signal to prioritize, or whether or not to perform RF retuning) based on any of the following (1), (2), and (3). (1) Terminal 200 may receive a second PDCCH. (2) Terminal 200 may receive PDSCH. (3) Terminal 200 may choose to receive a second PDCCH or PDSCH according to certain conditions. For example, terminal 200 may receive a PDSCH when no rate-matching is notified, and receive a second PDCCH when rate-matching is notified. Alternatively, terminal 200 may receive a second PDCCH if the second PDCCH is included in the Common Search Space (CSS), and receive a PDSCH if the second PDCCH is included in the UE-specific Search Space (USS).

[0116] In other words, if the reception timing of the PDSCH assigned by the first PDCCH and the second PDCCH are the same, the terminal 200 may decide to switch the reception frequency from the reception frequency resource of the first PDCCH to either the PDSCH's assigned frequency resource or the second PDCCH's assigned frequency resource, based on at least one of the signal type (e.g., data signal and control signal, or search space type) and the processing of the signal (e.g., whether rate-matching is appropriate).

[0117] For example, in Figure 10, terminal 200 does not switch the receiving frequency when it decides to receive the second PDCCH, but switches the receiving frequency when it decides to receive the PDSCH. Also, for example, in Figure 11, terminal 200 switches the receiving frequency to the frequency resource corresponding to the received signal (either the second PDCCH or the PDSCH) in both cases: when it decides to receive the second PDCCH and when it decides to receive the PDSCH.

[0118] (Default subband) In the above embodiment, one of the multiple subbands may be set as the "default subband". For example, when certain conditions such as the passage of a certain amount of time are met, the terminal 200 may switch the frequency of the receiving unit 202 from another subband to the default subband (or fall back) in order to enable reception of signals on the default subband.

[0119] For example, the PDCCH CSS signal may be transmitted in the default subband. This increases the likelihood that terminal 200 will receive the PDCCH CSS signal, enabling more stable operation.

[0120] Furthermore, for example, a synchronization signal or reference signal such as SSB (Synchronization Signal Block) may be transmitted in the default subband. This increases the likelihood that terminal 200 can receive the synchronization signal or reference signal, enabling more stable operation.

[0121] (BWP switching) In the above embodiment, terminal 200 may activate a different BWP from the active BWP, for example, in accordance with instructions from base station 100. In other words, terminal 200 may switch the active BWP. This BWP switching (also called retuning or switching, for example) may be a switch between simple BWPs, or a switch between a simple BWP and a normal BWP.

[0122] Furthermore, during BWP switching, the time resources before and after the switching timing may be set to a guard period (the name is just an example), and the transmission and reception of signals assigned to those resources may be omitted (e.g., omitted). For example, in the case of switching from BWP#1 to BWP#2, the transmission and reception of signals in the number of symbols or slots immediately before the switch in BWP#1 may be omitted, and the transmission and reception of signals in the number of symbols or slots immediately after the switch in BWP#2 may be omitted. Alternatively, signals in both the time resources immediately before the switch in BWP#1 and the time resources immediately after the switch in BWP#2 may be omitted.

[0123] In the BWP switching described above, the signals to be omitted (for example, the BWP in which the signal is omitted) may be determined according to some criteria. For example, the transmission and reception of signals that satisfy at least one of the following criteria may be omitted. (1) A data signal, a control signal (for example, a signal for the common search space or UE-specific search space), or a reference signal. (2) It is a down-line signal or an up-line signal. (3) Orthogonal sequences (e.g., Orthogonal Cover Code (OCC)) are not applicable.

[0124] For example, if the signals before and after BWP switching are a downlink control signal and a downlink data signal, the transmission and reception of the downlink data signal may be omitted if the control signal is in the Common search space, and the transmission and reception of the downlink control signal may be omitted if the control signal is in the UE-specific search space. This allows for the transmission and reception of higher-priority signals without omission. Note that the examples of setting importance (or priority) between signal types (e.g., data signals, control signals, or reference signals) are not limited to the above examples.

[0125] Furthermore, during BWP switching, for example, control signals and data signals may be assigned to time resources different from the guard period described above. In this case, rate-matching may be applied to the control signals and data signals. Also, for example, the application of rate-matching may be notified to terminal 200. Furthermore, for example, base station 100 may configure the search space to assign downlink control signals to time resources different from the guard period, or terminal 200 may determine that the time resource to which the control signals are assigned has shifted.

[0126] (Device type, identification) The above embodiment may be applied to, for example, a “RedCap terminal” or a non-RedCap terminal.

[0127] Furthermore, a RedCap terminal may be a terminal having at least one of the following characteristics (in other words, traits, attributes, or capabilities): (1) A terminal that notifies (e.g., reports) to base station 100 that it is a "terminal subject to coverage extension", a "terminal that receives repeatedly transmitted signals", or a "RedCap terminal". For example, uplink channels such as PRACH and PUSCH, or uplink signals such as Sounding Reference Signal (SRS) may be used for the above notification (report). (2) A terminal that meets at least one of the following capabilities, or a terminal that reports at least one of the following capabilities to base station 100. The above report may use, for example, uplink channels such as PRACH and PUSCH, or uplink signals such as UCI or SRS. - Terminals with a supported frequency bandwidth below a certain threshold (e.g., 20MHz, 40MHz, or 100MHz) - A terminal in which the number of implemented receiving antennas is below a threshold (for example, threshold = 1). - A terminal whose number of supported downlink ports (e.g., number of receiving antenna ports) is below a threshold (e.g., threshold = 2). - Terminals whose supported transmission rank count (e.g., maximum number of Multiple-Input Multiple-Output (MIMO) layers (or rank count)) is below a threshold (e.g., threshold = 2). - A terminal capable of transmitting and receiving signals in a frequency band above a threshold (for example, Frequency Range 2 (FR2) or a band of 52 GHz or higher). - Terminals whose processing time exceeds the threshold. - Terminals where the available transport block size (TBS) is below the threshold. - Terminals with a number of available transmission ranks (e.g., MIMO transmission layers) below a certain threshold. - Terminals with available modulation order below the threshold. - Terminals with a number of available Hybrid Automatic Repeat Request (HARQ) processes below the threshold. - Devices that support Rel-17 or later. (3) A terminal that receives parameters corresponding to a RedCap mobile station from base station 100. The parameters corresponding to a RedCap mobile station may include, for example, a Subscriber Profile ID for RAT / Frequency Priority (SPID).

[0128] Furthermore, "non-RedCap terminals" may also mean, for example, terminals that support Rel-15 / 16 (for example, terminals that do not support Rel-17), or terminals that support Rel-17 but do not have the above characteristics.

[0129] (Type of BWP) In the embodiment described above, the case in which the BWP bandwidth is wider than the bandwidth supported by terminal 200 was explained, but the invention is not limited to this, and the BWP bandwidth may be less than or equal to the bandwidth supported by terminal 200.

[0130] (Signal / channel type) In the above embodiment, the channels and signals of the downlink (e.g., PDCCH and PDSCH) were described, but the above embodiment may also be applied to the channels and signals of the uplink (e.g., any of PUCCH, PUSCH, and PRACH). For example, an example in which a downlink data signal (e.g., PDSCH) is assigned by PDCCH was described, but an uplink data signal (e.g., PUSCH) may also be assigned by PDCCH.

[0131] Furthermore, although the above embodiment describes a case where the resources of data signals (e.g., PDSCH or PUSCH) are allocated to the terminal 200 by PDCCH (e.g., downlink control information), it is not limited to this, and may be set by, for example, higher layer signals.

[0132] Furthermore, PDCCH may be transmitted in either the Common Search Space (CSS) or the UE Specific Search Space (USS), for example.

[0133] Furthermore, the notation "...part" in each of the embodiments described above may be replaced with other notations such as "...circuitry," "...device," "...unit," or "...module."

[0134] (supplement) Information indicating whether or not the terminal 200 supports the functions, operations, or processes described in the above-described embodiment may be transmitted (or notified) from the terminal 200 to the base station 100, for example, as capability information or capability parameters of the terminal 200.

[0135] The capability information may include an information element (IE) that individually indicates whether the terminal 200 supports at least one of the functions, operations, or processes shown in the embodiments described above. Alternatively, the capability information may include an information element that indicates whether the terminal 200 supports any two or more combinations of the functions, operations, or processes shown in each of the embodiments, each modification, and each supplement described above.

[0136] The base station 100 may, for example, determine (or decide or assume) which functions, operations, or processes the source terminal 200 supports (or does not support) based on capability information received from the terminal 200. The base station 100 may perform operations, processes, or controls in accordance with the determination result based on the capability information. For example, the base station 100 may control the allocation (in other words, scheduling) of at least one downlink resource such as PDCCH or PDSCH, and an uplink resource such as PUCCH or PUSCH, based on capability information received from the terminal 200.

[0137] Furthermore, the fact that terminal 200 does not support some of the functions, operations, or processes shown in the embodiments described above may be interpreted as the terminal 200 having restrictions on such some functions, operations, or processes. For example, information or requests regarding such restrictions may be notified to base station 100.

[0138] Information regarding the capabilities or limitations of terminal 200 may be defined, for example, in a standard, or it may be implicitly communicated to base station 100 in association with information known at base station 100 or information transmitted to base station 100.

[0139] (Control signal) In this disclosure, the downlink control signal (or downlink control information) related to one embodiment of this disclosure may be, for example, a signal (or information) transmitted in a Physical Downlink Control Channel (PDCCH) at the physical layer, or a signal (or information) transmitted in a Medium Access Control Control Element (MAC CE) or Radio Resource Control (RRC) at a higher layer. Furthermore, the signal (or information) is not limited to being notified by the downlink control signal, but may be predetermined in a specification (or standard), or may be pre-configured in the base station and terminal.

[0140] In this disclosure, the uplink control signal (or uplink control information) related to one embodiment of this disclosure may be, for example, a signal (or information) transmitted in the physical layer PUCCH, or a signal (or information) transmitted in the upper layer MAC CE or RRC. Furthermore, the signal (or information) is not limited to being notified by the uplink control signal, but may be predetermined in the specification (or standard), or may be pre-configured in the base station and terminal. In addition, the uplink control signal may be replaced with, for example, uplink control information (UCI), 1st stage sidelink control information (SCI), or 2nd stage SCI.

[0141] (base station) In one embodiment of this disclosure, the base station may be a Transmission Reception Point (TRP), cluster head, access point, Remote Radio Head (RRH), eNodeB (eNB), gNodeB (gNB), Base Station (BS), Base Transceiver Station (BTS), master unit, gateway, etc. In side-link communication, the terminal may also assume the role of a base station. Alternatively, instead of a base station, a relay device that relays communication between a higher-level node and a terminal may be used. It may also be a roadside unit.

[0142] (Uphill rink / Downhill rink / Side rink) One embodiment of the present disclosure may be applied to, for example, an uplink, a downlink, or a sidelink. For example, one embodiment of the present disclosure may be applied to the Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), Physical Random Access Channel (PRACH) of an uplink, the Physical Downlink Shared Channel (PDSCH), PDCCH, Physical Broadcast Channel (PBCH) of a downlink, or the Physical Sidelink Shared Channel (PSSCH), Physical Sidelink Control Channel (PSCCH), Physical Sidelink This may also be applied to Broadcast Channel (PSBCH).

[0143] PDCCH, PDSCH, PUSCH, and PUCCH are examples of downlink control channels, downlink data channels, uplink data channels, and uplink control channels, respectively. PSCCH and PSSCH are examples of sidelink control channels and sidelink data channels. PBCH and PSBCH are examples of broadcast channels, and PRACH is an example of a random access channel.

[0144] (Data channel / Control channel) One embodiment of the present disclosure may be applied to either a data channel or a control channel, for example. For example, the channel in one embodiment of the present disclosure may be replaced with any of the data channels PDSCH, PUSCH, PSSCH, or the control channels PDCCH, PUCCH, PBCH, PSCCH, PSBCH.

[0145] (reference signal) In one embodiment of the present disclosure, the reference signal is, for example, a signal known to both the base station and the mobile station, and may be called a Reference Signal (RS) or pilot signal. The reference signal may be any of the following: 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).

[0146] (Time interval) In one embodiment of the present disclosure, the unit of time resource is not limited to one or a combination of slots and symbols, but may also be a time resource unit such as a frame, superframe, subframe, slot, time slot subslot, minislot, or symbol, Orthogonal Frequency Division Multiplexing (OFDM) symbol, Single Carrier - Frequency Division Multiplexing (SC-FDMA) symbol, or any other time resource unit. Furthermore, the number of symbols contained in one slot is not limited to the number of symbols exemplified in the above embodiment, but may be any other number of symbols.

[0147] (Frequency band) One embodiment of this disclosure may be applied to either a licensed band or an unlicensed band. A channel access procedure (Listen Before Talk (LBT), carrier sense, Channel Clear Assessment (CCA)) may be performed before the transmission of each signal.

[0148] (communication) One embodiment of the present disclosure may be applied to communication between a base station and a terminal (Uu-link communication), communication between terminals (Sidelink communication), or 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.

[0149] Furthermore, one embodiment of this disclosure may be applied to any of the following: a terrestrial network, a satellite, or a non-terrestrial network (NTN) using a high-altitude pseudo-satellite (HAPS). Also, one embodiment of this disclosure may be applied to terrestrial networks with large cell sizes, ultra-wideband transmission networks, and other networks where transmission delay is large relative to symbol length or slot length.

[0150] (Antenna port) In one embodiment of this 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, but may refer to an array antenna composed of multiple antennas. For example, the number of physical antennas that make up an antenna port is not specified, and it may be defined as the smallest unit on which a terminal station can transmit a reference signal. Alternatively, an antenna port may be defined as the smallest unit on which the weighting of a precoding vector is multiplied.

[0151] <5G NR System Architecture and Protocol Stack> 3GPP is continuing work on the next release of fifth-generation mobile phone technology (also simply called "5G"), which includes the development of new radio access technologies (NR) operating in the frequency range up to 100 GHz. The initial version of the 5G standard was completed at the end of 2017, which will enable the prototyping and commercial deployment of devices (e.g., smartphones) that comply with the 5G NR standard.

[0152] For example, the system architecture as a whole assumes an NG-RAN (Next Generation - Radio Access Network) with gNBs. The gNBs provide the UE-side termination for the user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocols of the NG radio access. The gNBs are connected to each other by Xn interfaces. Furthermore, the gNBs are connected to the NGC (Next Generation Core) by Next Generation (NG) interfaces, more specifically to the AMF (Access and Mobility Management Function) (e.g., a specific core entity performing AMF) by NG-C interfaces, and to the UPF (User Plane Function) (e.g., a specific core entity performing UPF) by NG-U interfaces. The NG-RAN architecture is shown in Figure 12 (see, for example, 3GPP TS 38.300 v15.6.0, section 4).

[0153] The NR user plane protocol stack (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, RLC (Radio Link Control (see section 6.3 of TS 38.300)) sublayer, and MAC (Medium Access Control (see section 6.2 of TS 38.300)) sublayer, which are terminated on the network side in gNB. Additionally, a new Access Stratum (AS) sublayer (SDAP: Service Data Adaptation Protocol) is introduced on top of PDCP (see, for example, 3GPP TS 38.300, section 6.5). Furthermore, a control plane protocol stack is defined for NR (see, for example, TS 38.300, section 4.4.2). An overview of Layer 2 functionality is described in section 6 of TS 38.300. The functions of the PDCP sublayer, RLC sublayer, and 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.

[0154] For example, the Medium-Access-Control layer handles scheduling and scheduling-related functions, including the multiplexing of logical channels and the handling of various neural networks.

[0155] For example, the Physical Layer (PHY) is responsible for coding, PHY HARQ processing, modulation, multi-antenna processing, and mapping signals to appropriate physical time-frequency resources. The Physical Layer also 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 transmitting a particular transport channel, and each transport channel is mapped to a corresponding physical channel. For example, physical channels include uplink physical channels such as PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel), and downlink physical channels such as PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), and PBCH (Physical Broadcast Channel).

[0156] NR use cases / deployment scenarios may include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine type communications (mMTC), each with diverse requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps on the downlink and 10 Gbps on the uplink) and effective (user-experienced) data rates approximately three times that of IMT-Advanced. URLLC, on the other hand, imposes more stringent requirements for ultra-low latency (0.5 ms for both UL and DL for user plane latency) and high reliability (1-10⁻⁵ within 1 ms). Finally, mMTC preferably has a high connectivity density (1,000,000 devices / km² in urban environments). 2 ), wide coverage in harsh environments, and extremely long-lasting batteries (15 years) for low-cost devices may be required.

[0157] Therefore, an OFDM neurology suitable for one use case (e.g., subcarrier spacing, OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) may not be effective for other use cases. For example, low-latency services may preferably require a shorter symbol length (and thus a larger subcarrier spacing) and / or fewer symbols per scheduling interval (also known as TTI) than mMTC services. Furthermore, deployment scenarios with large channel delay spreads may preferably require a longer CP length than scenarios with short delay spreads. The subcarrier spacing may be optimized on a case-by-case basis to maintain similar CP overhead. There may be one or more subcarrier spacing values ​​supported by NR. Accordingly, subcarrier spacings of 15kHz, 30kHz, 60kHz, etc. are currently being considered. The symbol length Tu and subcarrier spacing Δf are directly related by the equation 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.

[0158] In the new 5G-NR wireless system, resource grids for subcarriers and OFDM symbols are defined for each neurology and each carrier, for both 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).

[0159] <Functional separation between NG-RAN and 5GC in 5G NR> Figure 13 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.

[0160] For example, gNB and ng-eNB host the following main functions: - Radio resource management functions such as radio bearer control, radio admission control, connection mobility control, and dynamic allocation (scheduling) of resources to UEs on both uplink and downlink; - Compression, encryption, and integrity protection of the IP header of the data; - Selection of the AMF when the UE attaches if routing to the AMF cannot be determined from the information provided by the UE; - Routing of user plane data toward UPF; - Routing of control plane information to AMF; - Setting up and disconnecting connections; - Scheduling and sending paging messages; - Scheduling and transmission of system notification information (originating from AMF or Operation, Admission, Maintenance functions (OAM)); - Setting up measurements and measurement reporting for mobility and scheduling; - Transport-level packet marking on 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; - NAS message delivery function; - Sharing of wireless access network; Dual connectivity; - Close cooperation between NR and E-UTRA.

[0161] The Access and Mobility Management Function (AMF) hosts the following main functions: - A function to terminate Non-Access Stratum (NAS) signaling; - Security of NAS signaling; - Security control of Access Stratum (AS); - Core Network (CN) node-to-node signaling for mobility between 3GPP access networks; - Reachability of the UE in idle mode (including control and execution of paging retransmissions); - Management of registration areas; - Support for intra-system and inter-system mobility; - Access authentication; - Access authorization including roaming permission checks; - Mobility management and control (enrollment and policies); - Support for network slicing; - Selection of Session Management Function (SMF).

[0162] Furthermore, the User Plane Function (UPF) hosts the following main functions: - Anchor points for intra-RAT mobility / inter-RAT mobility (where applicable); - External PDU (Protocol Data Unit) session points for interconnection with data networks; - Routing and forwarding of packets; - Packet inspection and enforcement of policy rules in the user plane. - Reporting traffic usage; - Uplink classifier to support routing of traffic flow to data networks; - 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 SDF); - Downlink packet buffering and triggering function for downlink data notification.

[0163] 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 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.

[0164] <Procedures for RRC connection setup and reconfiguration> Figure 14 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).

[0165] RRC is a higher-layer signaling protocol used for configuring UEs and gNBs. During this transition, the AMF prepares UE context data (including, for example, PDU session context, security key, UE Radio Capability, UE Security Capabilities, etc.) and sends it to the gNB along 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, to which the UE responds with a SecurityModeComplete message. Subsequently, the gNB sends an RRCReconfiguration message to the UE, and upon receiving an RRCReconfigurationComplete from the UE, the gNB reconfigures itself to set up the Signaling Radio Bearer 2 (SRB2) and Data Radio Bearer (DRB). For signaling-only connections, the RRCReconfiguration step is omitted because SRB2 and DRB are not set up. Finally, gNB notifies AMF that the setup procedure is complete with an Initial Context Setup Response.

[0166] Accordingly, this disclosure provides a 5th Generation Core (5GC) entity (e.g., AMF, SMF, etc.) comprising a control circuit that establishes a Next Generation (NG) connection with a gNodeB during operation, and a transmission unit that sends an initial context setup message to the gNodeB via the NG connection during operation so that a signaling radio bearer between the gNodeB and the user equipment (UE) is set up. Specifically, the gNodeB transmits Radio Resource Control (RRC) signaling, including an Information Element (IE), to the UE via the signaling radio bearer. The UE then transmits on the uplink or receives on the downlink based on the resource allocation setting.

[0167] <IMT Usage Scenarios from 2020 Onward> Figure 15 shows some use cases for 5G NR. The 3rd generation partnership project for new radio (3GPP NR) is considering three use cases envisioned by IMT-2020 to support a wide variety of services and applications. The first phase of specification development for enhanced mobile-broadband (eMBB) has been completed. Current and future work will include expanding eMBB support, as well as standardization for ultra-reliable and low-latency communications (URLLC) and massive machine-type communications (mMTC). Figure 15 shows some examples of conceptual use scenarios for IMT beyond 2020 (see, for example, ITU-R M.2083 Figure 2).

[0168] URLLC use cases have stringent performance requirements, such as throughput, latency, and availability. URLLC use cases are envisioned as one of the key technologies to enable future applications such as wireless control of industrial production or manufacturing processes, telemedicine 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, a key requirement is that the target user plane latency is 0.5 ms for UL (uplink) and 0.5 ms for DL ​​(downlink). The general URLLC requirement for a single packet transmission is a block error rate (BLER) of 1E-5 for a 32-byte packet size when the user plane latency is 1 ms.

[0169] From a physical layer perspective, reliability can be improved in many ways. Current room for reliability improvement includes defining a separate CQI table for URLLC, a more compact DCI format, and PDCCH iterations. However, this room for improvement may expand towards achieving ultra-high reliability as NR becomes more stable and developed (in terms of critical requirements for NR URLLC). Specific use cases for NR URLLC in Release 15 include augmented reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0170] Furthermore, the technical enhancements targeted by NR URLLC aim to improve latency and reliability. Technical enhancements for latency improvement include configurable neurology, non-slot-based scheduling with flexible mapping, grant-free (configured grant) uplink, slot-level iteration on data channels, and preemption on downlink. Preemption means that a transmission for which a resource has already been allocated is stopped, and that allocated resource is used for other transmissions with lower latency / higher priority requirements that are requested later. Thus, transmissions that were already permitted are replaced by later transmissions. Preemption 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 (eMBB, etc.). Technical enhancements for reliability improvement include a dedicated CQI / MCS table for the 1E-5 target BLER.

[0171] A key characteristic of mMTC (massive machine type communication) use cases is the extremely large number of connected devices that typically transmit relatively small amounts of data that are less susceptible to latency. These devices require low cost and very long battery life. From a noise reduction (NR) perspective, utilizing a very narrow bandwidth is one solution that saves power from the user interface (UE) and extends battery life.

[0172] As mentioned above, the scope of reliability improvements in NR is expected to broaden. High reliability or very high reliability is a critical requirement in all cases, for example, for URLLC and mMTC. Several mechanisms can improve reliability from both a radio and network perspective. Generally, 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 in the frequency, time, and / or spatial domains. These areas are generally applicable to reliability improvements regardless of the specific communication scenario.

[0173] Regarding NR URLLC, further use cases with more stringent requirements are envisioned, such as factory automation, transportation, and power distribution. These stringent requirements include high reliability (up to 10⁻⁶ levels), high availability, packet size up to 256 bytes, and time synchronization down to a few microseconds (depending on the use case, the value can be 1 microsecond or a few microseconds depending on the frequency range and short latency of approximately 0.5 ms to 1 ms (e.g., 0.5 ms latency in the target user plane)).

[0174] Furthermore, for NR URLLC, several technical enhancements may be possible from the perspective of the physical layer. These technical enhancements include enhancements to the Physical Downlink Control Channel (PDCCH) related to compact DCI, repetition of the PDCCH, and increased monitoring of the PDCCH. Also, the enhancement of Uplink Control Information (UCI) is related to the enhancement of enhanced Hybrid Automatic Repeat Request (HARQ) and CSI feedback. Additionally, enhancements to the Physical Uplink Shared Channel (PUSCH) related to mini-slot level hopping, and enhancements to retransmission / repetition may be possible. The term "mini-slot" refers to a Transmission Time Interval (TTI) that contains fewer symbols than a slot (a slot has 14 symbols).

[0175] <QoS Control> The Quality of Service (QoS) model of 5G is based on QoS flows and supports both QoS flows that require a guaranteed flow bit rate (Guaranteed Bit Rate QoS flows, GBR) 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 granularity of QoS differentiation within 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.

[0176] For each UE, the 5GC establishes one or more PDU sessions. For each UE, the NG-RAN establishes at least one Data Radio Bearers (DRB) in accordance with the PDU session, as shown above, for example, referring to Figure 14. Additional DRBs for the QoS flow of that PDU session can be configured later (when this is done is up to the NG-RAN). The NG-RAN maps packets belonging to various PDU sessions to various DRBs. NAS-level packet filters in the UE and 5GC associate UL and DL packets with QoS flows, while AS-level mapping rules in the UE and NG-RAN associate UL and DL QoS flows with DRBs.

[0177] Figure 16 shows the non-roaming reference architecture for 5G NR (see TS 23.501 v16.1.0, section 4.23). An Application Function (AF) (for example, an external application server hosting 5G services, as illustrated in Figure 15) interacts with the 3GPP core network to provide services. This may involve accessing the Network Exposure Function (NEF) to support applications that affect traffic routing, or interacting with the policy framework for policy control (e.g., QoS control) (see Policy Control Function (PCF)). Based on operator deployment, Application Functions considered trusted by the operator can interact directly with the relevant Network Functions. Application Functions not authorized by the operator to directly access the Network Functions interact with the relevant Network Functions using an external exposure framework via the NEF.

[0178] Figure 16 further illustrates the functional units of the 5G architecture, namely the 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.

[0179] Accordingly, the Disclosure provides an application server (e.g., AF in a 5G architecture) comprising: a transmitter that, in operation, transmits a request to at least one of the 5GC functions (e.g., NEF, AMF, SMF, PCF, UPF, etc.) that includes QoS requirements for at least one of the URLLC service, eMMB service, and mMTC service, in order to establish a PDU session including a radio bearer between the gNodeB and UE in accordance with QoS requirements; and a control circuit that, in operation, performs the service using the established PDU session.

[0180] This disclosure can be implemented as software, hardware, or software in conjunction with hardware. Each functional block used in the description of the above embodiments may be implemented partially or entirely as an integrated circuit (LSI), and each process described in the above embodiments may be controlled partially or entirely by a single LSI or a combination of LSIs. An LSI may consist of individual chips, or it may consist of a single chip that includes some or all of the functional blocks. An LSI may have data inputs and outputs. Depending on the degree of integration, LSIs may be referred to as ICs, system LSIs, super LSIs, or ultra LSIs. The method of integrated circuit implementation is not limited to LSIs, and may also be implemented with dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, an FPGA (Field Programmable Gate Array) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. This disclosure may be implemented as digital processing or analog processing. Furthermore, if advancements in semiconductor technology or other derived technologies lead to the emergence of integrated circuit technologies that replace LSIs, then naturally, it would be possible to use those technologies to integrate functional blocks. The application of biotechnology, for example, is a possibility.

[0181] This disclosure is applicable to all types of devices, systems, and equipment having communication capabilities (collectively referred to as communication equipment). Communication equipment may include a radio transceiver and a processing / control circuit. A radio transceiver may include a receiver and a transmitter, or both as functions. A radio transceiver (transmitter, receiver) may include an RF (Radio Frequency) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or similar. Non-exclusive 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 devices, vehicles or mobile transport with communication capabilities (cars, airplanes, ships, etc.), and combinations of the above-mentioned devices.

[0182] Communication devices are not limited to portable or movable devices, but also include all kinds of non-portable or fixed devices, devices, and systems, such as smart home devices (appliances, lighting equipment, smart meters or measuring instruments, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0183] Communication includes data communication via cellular systems, wireless LAN systems, and communication satellite systems, as well as data communication using combinations of these.

[0184] Furthermore, the communication device also includes devices such as controllers and sensors that are connected to or linked to a communication device that performs the communication functions described in this disclosure. For example, this includes controllers and sensors that generate control signals and data signals used by the communication device that performs the communication functions of the communication device.

[0185] Furthermore, communication equipment includes infrastructure facilities such as base stations, access points, and any other devices, devices, and systems that communicate with or control the aforementioned non-limited types of equipment.

[0186] A terminal according to one embodiment of the present disclosure comprises a control circuit that sets the receiving frequency resource for a second control signal received after receiving a first control signal in a first frequency resource to a second frequency resource that includes a frequency resource different from the first frequency resource, and a receiving circuit that receives the second control signal in the second frequency resource.

[0187] In one embodiment of the present disclosure, the control circuit sets the second frequency resource based on the third frequency resource of the data signal assigned by the first control signal.

[0188] In one embodiment of the present disclosure, the control circuit determines the setting of the second frequency resource based on the setting of the resource associated with the bandwidth portion allocated to the terminal.

[0189] In one embodiment of the present disclosure, the control circuit determines the setting of the second frequency resource based on the setting of the first frequency resource.

[0190] In one embodiment of the present disclosure, the control circuit sets the first frequency resource in at least one of the first subband and the second subband, and sets the second frequency resource in the first subband and the second subband.

[0191] In one embodiment of the present disclosure, the control circuit, if it fails to receive the first control signal in the first subband and the second subband, decides to receive the second control signal in the subband corresponding to the first frequency resource, and if it succeeds in receiving the first control signal, decides to receive the second control signal in a subband different from the subband corresponding to the first frequency resource.

[0192] In one embodiment of the present disclosure, if the timing of receiving the data signal assigned by the first control signal and the second control signal are the same, the control circuit determines, based on the signal type and at least one of the processing of the signal, to switch the receiving frequency from the first frequency resource to either the second frequency resource or the third frequency resource to which the data signal is assigned.

[0193] A base station according to one embodiment of the present disclosure includes a control circuit that sets the frequency resource of a second control signal received by a terminal after it has received a first control signal in a first frequency resource to a second frequency resource that includes a frequency resource different from the first frequency resource, and a receiving circuit that transmits the second control signal in the second frequency resource.

[0194] In a communication method according to one embodiment of the present disclosure, the terminal sets the receiving frequency resource for the second control signal to be received after receiving the first control signal in the first frequency resource to a second frequency resource that includes a frequency resource different from the first frequency resource, and receives the second control signal in the second frequency resource.

[0195] In a communication method according to one embodiment of the present disclosure, the base station sets the frequency resource for a second control signal received by a terminal after it has received a first control signal in a first frequency resource to a second frequency resource that includes a different frequency resource from the first frequency resource, and transmits the second control signal in the second frequency resource.

[0196] All disclosures in the specification, drawings, and abstract contained in the Japanese application 2021-053461, filed on March 26, 2021, are incorporated herein by reference. [Industrial applicability]

[0197] One embodiment of this disclosure is useful for wireless communication systems. [Explanation of Symbols]

[0198] 100 base stations 101,206 Control Unit 102 DCI generation section 103 Upper Layer Signal Generation Unit 104,207 Encoding and Modulation Section 105 Signal arrangement section 106,208 Transmitter 107,201 antennas 108,202 Receiving Unit 109,205 Demodulation / Decoding Unit 200 terminals 203 Signal separation section 204 DCI detection unit

Claims

1. A control circuit sets the receiving frequency resource for a second control signal received after receiving a data signal allocated by a first control signal in a first frequency resource to a second frequency resource that includes a frequency resource different from the first frequency resource, A receiving circuit that receives the second control signal in the second frequency resource, It is equipped with, The control circuit sets one of the frequency resources within the range of the third frequency resource of the data signal assigned by the first control signal to the second frequency resource. Terminal.

2. The control circuit determines the setting of the second frequency resource based on the setting of the resource associated with the bandwidth portion allocated to the terminal. The terminal according to claim 1.

3. The control circuit determines the setting in the second frequency resource based on the setting in the first frequency resource. The terminal according to claim 1.

4. The control circuit sets the second frequency resource in both the first subband corresponding to the first frequency resource and the second subband corresponding to the third frequency resource. The terminal according to claim 1.

5. The control circuit determines to receive the second control signal in the second subband when a frequency switch is performed from the first subband to the second subband, and determines to receive the second control signal in the first subband when the frequency switch is not performed. The terminal according to claim 4.

6. If the data signal assigned by the first control signal and the reception timing of the second control signal are the same, The control circuit determines, based on at least one of the signal type and the processing of the signal, to switch the receiving frequency from the first frequency resource to either the second frequency resource or the third frequency resource to which the data signal is assigned. The terminal according to claim 1.

7. A control circuit sets the frequency resource of a second control signal received by a terminal after it has received a data signal assigned by a first control signal in a first frequency resource to a second frequency resource that includes a frequency resource different from the first frequency resource. A transmitting circuit that transmits the second control signal in the second frequency resource, It is equipped with, The control circuit sets one of the frequency resources within the range of the third frequency resource of the data signal assigned by the first control signal to the second frequency resource. Base station.

8. The device is, The receiving frequency resource for the second control signal, which is received after receiving the data signal assigned by the first control signal in the first frequency resource, is set to a second frequency resource that includes a frequency resource different from the first frequency resource. The second frequency resource receives the second control signal, The second frequency resource is set to any of the frequency resources within the range of the third frequency resource of the data signal allocated by the first control signal. Communication method.

9. The base station is, The frequency resource of the second control signal received by the terminal after it has received a data signal assigned by the first control signal in the first frequency resource is set to a second frequency resource that includes a different frequency resource from the first frequency resource. The second control signal is transmitted in the second frequency resource. The second frequency resource is set to any of the frequency resources within the range of the third frequency resource of the data signal allocated by the first control signal. Communication method.

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