Terminal, base station, communication method and integrated circuit

Abstract

The present invention uses reference signals to improve channel estimation accuracy. A terminal includes: a control circuit configured to set a first upper limit value of a frequency interval for configuring a first reference signal in a first bandwidth to be smaller than a second upper limit value of a frequency interval for configuring a second reference signal in a second bandwidth, the second bandwidth being wider than the first bandwidth; and a transmission circuit configured to transmit the first reference signal based on the first upper limit value.

Description

Technical Field

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

[0002] In Release 17 (hereinafter referred to as "Rel. 17") of the 3rd Generation Partnership Project (3GPP), in order to achieve functional expansion of Multiple-Input Multiple Output (MIMO) applied to the new radio access technology (NR), improvements in the coverage performance or capacity performance of the sounding reference signal (SRS) were studied (for example, refer to non-patent document 1).

[0003] Prior art literature

[0004] Non-patent literature

[0005] Non-Patent Document 1: RP-192436, “WID proposal for Rel.17 enhancements on MIMO for NR”, Samsung, December 2019

[0006] Non-Patent Document 2: 3GPP TS 38.211 V16.1.0, "NR; Physical channels and modulation (Release 16)," 2020-03 Summary of the Invention

[0007] However, there is still room for research on methods of using reference signals to improve channel estimation accuracy.

[0008] Non-limiting embodiments of the present disclosure contribute to providing a terminal, a base station, and a communication method that improve the accuracy of channel estimation using a reference signal.

[0009] A terminal according to one embodiment of the present disclosure includes: a control circuit configured to set a first upper limit value of a frequency interval for configuring a first reference signal in a first bandwidth to be smaller than a second upper limit value of a frequency interval for configuring a second reference signal in a second bandwidth, where the second bandwidth is wider than the first bandwidth; and a transmitting circuit configured to transmit the first reference signal based on the first upper limit value.

[0010] It should be noted that these general or specific aspects may be implemented by a system, device, method, integrated circuit, computer program or recording medium, or by any combination of systems, devices, methods, integrated circuits, computer programs and recording media.

[0011] According to one embodiment of the present disclosure, the accuracy of channel estimation using a reference signal can be improved.

[0012] Further advantages and effects of an embodiment of the present disclosure will be clarified through the description and drawings. These advantages and / or effects are provided by several embodiments and the features described in the description and drawings, but not all of them need to be provided in order to obtain one or more of the same features. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing an example of transmission of a narrowband sounding reference signal (SRS: Sounding Reference Signal).

[0014] Figure 2 This is a diagram showing an example of the relationship between the SRS transmission bandwidth, the number of transmission combs, and the SRS generation sequence length.

[0015] Figure 3 This is a block diagram showing a configuration example of a portion of a base station.

[0016] Figure 4 This is a block diagram showing a configuration example of a part of a terminal.

[0017] Figure 5 This is a block diagram showing a configuration example of a base station.

[0018] Figure 6 This is a block diagram showing a structural example of a terminal.

[0019] Figure 7 This is a sequence diagram showing an example of operations of a base station and a terminal.

[0020] Figure 8 This is a diagram showing an example of the relationship between the SRS transmission bandwidth and the number of transmission combs in the first embodiment.

[0021] Figure 9 This is a diagram showing an example of the relationship among the SRS transmission bandwidth, the number of transmission combs, and the SRS generation sequence length according to the first embodiment.

[0022] Figure 10 This is a diagram showing another example of the relationship between the SRS transmission bandwidth and the number of transmission combs in the first embodiment.

[0023] Figure 11This is a diagram showing another example of the relationship among the SRS transmission bandwidth, the number of transmission combs, and the SRS generation sequence length according to the first embodiment.

[0024] Figure 12 This is a diagram showing an example of SRS frequency hopping.

[0025] Figure 13 This is a diagram showing an example of SRS frequency hopping according to the second embodiment.

[0026] Figure 14 This is a diagram showing an example of SRS frequency hopping according to the second embodiment.

[0027] Figure 15 This is a diagram showing an example of SRS frequency hopping according to the second embodiment.

[0028] Figure 16 is a diagram of an exemplary architecture of a 3GPP NR system.

[0029] Figure 17 This diagram shows the functional separation between NG-RAN (Next Generation-Radio Access Network) and 5GC (5th Generation Core).

[0030] Figure 18 This is a sequence diagram of the process of setting up / resetting an RRC (Radio Resource Control) connection.

[0031] Figure 19 This diagram illustrates the use cases for enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable and low-latency communications (URLLC).

[0032] Figure 20 is a block diagram representing an exemplary 5G system architecture for a non-roaming scenario. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0034] Regarding the SRS used in NR (for example, referred to as "NR SRS"), for example, a base station (for example, sometimes also referred to as "eNB" or "gNB") can notify (or set) information related to the setting of the SRS (hereinafter referred to as "SRS setting information") to a terminal (for example, sometimes also referred to as "user equipment (UE)"). In the SRS setting information, for example, the parameter group for each SRS resource, namely, an "SRS resource set (resource set)", such as the transmission timing of the SRS, the transmission frequency band of the SRS, the sequence number for reference signal generation, the number of transmission combs (or the number of transmission subcarriers), and the cyclic shift amount can be defined. For example, the SRS setting information can be set using higher-layer signaling such as the radio resource control (RRC) layer. In addition, the SRS setting information is sometimes referred to as "SRS-Config" set in the RRC layer.

[0035] As an example of a method for transmitting NR SRS in a frequency band, a "wideband SRS transmission method" and a "narrowband SRS transmission method" can be cited. The wideband can be, for example, a frequency band corresponding to a frequency band in which SRS can be transmitted (for example, called a "sounding bandwidth" or a "frequency band in which a channel can be estimated"). In addition, the narrowband can be, for example, a frequency band narrower than the sounding band (or wideband). In the wideband SRS transmission method, for example, SRS can be transmitted in a transmission bandwidth equivalent to a bandwidth part (BWP: Bandwidth part), and wideband channel estimation can be performed at one time. In addition, in the narrowband SRS transmission method, for example, SRS can be transmitted in a narrowband while changing the transmission band over time (in other words, performing frequency hopping), and wideband channel estimation can be performed using multiple narrowband SRSs.

[0036] For example, the path loss of a terminal located near a cell border is greater than that of a terminal located near the center of a cell. In addition, there is an upper limit to the maximum transmission power of a terminal. Therefore, for example, if an SRS is transmitted in a wide band by a terminal located near a cell border, the received power per unit frequency in the base station is likely to decrease. Therefore, if an SRS is transmitted in a wide band by a terminal located near a cell border, for example, the reception quality (for example, the signal to interference and noise ratio (SINR)) is reduced, and the channel estimation accuracy is degraded. Therefore, for example, the following narrowband SRS transmission method can be applied to a terminal located near a cell border, which concentrates the allocation of transmission power on a narrowband frequency band narrower than the wideband (in other words, increases the transmission power density) and transmits.

[0037] On the other hand, for example, a terminal near the center of a cell experiences less path loss than a terminal near a cell boundary. Therefore, even if a terminal near the center of a cell transmits SRS in a wideband, the base station can maintain sufficient received power per unit frequency for channel estimation, enabling the application of a wideband SRS transmission method.

[0038] Furthermore, for example, for NR SRS, whether it is wideband SRS or narrowband SRS, the sounding band can be set uniformly across terminals. In this case, for example, the transmission bandwidth of the wideband SRS can be set to N times (N is an integer) the transmission bandwidth of the narrowband SRS. For example, when a terminal transmits a narrowband SRS, by applying N frequency hopping, the channel quality of the same frequency band as the wideband SRS can be estimated.

[0039] For example, for NR SRS, the minimum transmission bandwidth of SRS can be 4 resource blocks (RBs), and the transmission bandwidth of SRS (for example, the number of RBs) can be a multiple of 4 (for example, refer to non-patent document 2).

[0040] Figure 1 This is a diagram showing an example of transmitting narrowband SRS in NR SRS.

[0041] exist Figure 1 In , the detection bandwidth is, for example, 16 RB. Figure 1 In the embodiment, the terminal can perform four frequency hopping on an SRS with a transmission bandwidth of 4 RB (eg, a narrowband SRS).

[0042] 3GPP Rel. 17, for example, envisions a method for increasing the SRS transmission power density during narrowband SRS transmission. Increasing the SRS transmission power density can improve channel estimation accuracy for terminals with high path loss, such as those near cell boundaries, and thus improve SRS coverage performance.

[0043] Methods for increasing the SRS transmission power density include, for example, reducing the SRS transmission bandwidth or increasing the number of transmission combs (in other words, widening the transmission subcarrier spacing). Alternatively, frequency hopping can be applied to narrowband SRS transmissions, and channel estimation can be performed over a wideband.

[0044] However, as the SRS transmission bandwidth is reduced or the number of transmitted combs is increased, the length of the SRS generation sequence decreases. For example, as the length of the SRS generation sequence decreases, the cross-correlation (or interference) between SRSs using different sequences increases, degrading channel estimation accuracy.

[0045] Furthermore, the shorter the sequence length of the SRS generation sequence, the fewer sequences with good peak-to-average power ratio (PAPR) or cross-correlation characteristics (e.g., constant envelope zero autocorrelation (CAZAC) characteristics). For example, in NR, an SRS generation sequence can be used every 30 sequences in each transmission bandwidth. By transmitting SRSs generated using different sequences in adjacent cells, interference between adjacent cells can be reduced. For example, the shorter the sequence length of the SRS generation sequence, the greater the cross-correlation (or interference), which degrades channel estimation accuracy.

[0046] For example, the sequence length "M" of the SRS generation sequence sc,b SRS " can be calculated based on formula (1) (for example, refer to non-patent document 2).

[0047] [Formula 1]

[0048]

[0049] In formula (1), m SRS,b Indicates the transmission bandwidth of SRS [RB], N sc RB Indicates the number of subcarriers (sc) per RB [sc / RB], K TC Indicates the number of sent combs (comb interval) [sc].

[0050] In NR, for example, N sc RB =12 (fixed value). In this case, for example, the SRS transmission bandwidth (m SRS,b ), send Comb number (K TC ) and sequence length (M sc,b SRS ) is in Figure 2 For example, Figure 2 As shown, when the SRS transmission bandwidth is less than 2 RB, the sequence length may sometimes fall below a certain threshold (e.g., 3 [sc]) depending on the number of transmitted combs. For example, if the sequence length falls below a certain threshold (e.g., 3 [sc]), the cross-correlation (interference) between SRSs increases, potentially degrading the accuracy of SRS-based channel estimation.

[0051] Therefore, in one embodiment of the present disclosure, a method of improving the accuracy of channel estimation using SRS is described.

[0052] (Implementation 1)

[0053] [Overview of the Communication System]

[0054] 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).

[0055] For example, the base station 100 may be a base station for NR, and the terminal 200 may be a terminal for NR. The base station 100 may, for example, set SRS configuration information related to SRS transmission for the terminal 200, and receive the SRS from the terminal 200. In addition, the terminal 200 may, for example, transmit the SRS in a predetermined (or configured) transmission frequency band, with a certain bandwidth and number of transmission combs, based on the SRS configuration information from the base station 100.

[0056] Figure 3 This is a block diagram showing a configuration example of a portion of a base station 100 according to one embodiment of the present disclosure. Figure 3 In the illustrated base station 100, a control unit 101 (e.g., corresponding to a control circuit) sets a first upper limit value of a frequency interval (e.g., the number of transmission combs) for allocating a first reference signal (e.g., SRS) in a first bandwidth to be lower than a second upper limit value of a frequency interval for allocating a second reference signal (e.g., SRS) in a second bandwidth wider than the first bandwidth. A receiving unit 105 (e.g., corresponding to a receiving circuit) receives the first reference signal based on the first upper limit value.

[0057] Figure 4 1 is a block diagram showing a configuration example of a portion of the terminal 200 according to one embodiment of the present disclosure. Figure 4 In the illustrated terminal 200, the control unit 203 (e.g., corresponding to a control circuit) sets a first upper limit value of the frequency interval (e.g., the number of transmission combs) for configuring a first reference signal (e.g., SRS) in a first bandwidth to be lower than a second upper limit value of the frequency interval for configuring a second reference signal (e.g., SRS) in a second bandwidth wider than the first bandwidth. The transmitting unit 206 (e.g., corresponding to a transmitting circuit) transmits the first reference signal based on the first upper limit value.

[0058] [Structure of base station]

[0059] Figure 5 1 is a block diagram showing a configuration example of a base station 100 according to one embodiment of the present disclosure. Figure 4 In the embodiment, the base station 100 may include, for example, a control unit 101, a coding / modulation unit 102, a transmission processing unit 103, a transmission unit 104, a reception unit 105, a reception processing unit 106, and a reference signal reception unit 107.

[0060] The control unit 101 may control, for example, SRS scheduling. For example, the control unit 101 may generate SRS setting information for the target terminal 200 .

[0061] The SRS resource set of the SRS setting information may include, for example, parameters such as the transmission band of each SRS resource (for example, including the transmission bandwidth, the number of transmission combs or the hopping mode), the transmission code element position, the number of SRS ports, the sequence number for generating the reference signal, the cyclic shift amount (for example, the cyclic shift value) or the sequence hopping.

[0062] The control unit 101 may output control information including the generated SRS setting information to the coding / modulation unit 102, for example. After undergoing transmission processing in the coding / modulation unit 102, the transmission processing unit 103, and the transmission unit 104, the SRS setting information may be transmitted to the target terminal 200 as, for example, RRC layer control information (in other words, higher layer signaling or RRC signaling).

[0063] Furthermore, the control unit 101 may control the reception of the SRS based on the SRS setting information. For example, the control unit 101 may output the SRS setting information to the reception processing unit 106.

[0064] Furthermore, the control unit 101 may generate, for example, allocation information of frequency resources (eg, RBs) for downlink data, and output, for example, allocation information of radio resources for downlink data transmission to the transmission processing unit 103 .

[0065] The coding / modulation unit 102 may encode and modulate the SRS configuration information input from the control unit 101 , for example, and output the obtained modulated signal to the transmission processing unit 103 .

[0066] For example, the transmission processing unit 103 may map the modulated signal input from the coding / modulation unit 102 to a frequency band based on the allocation information of the wireless resources for downlink data transmission input from the control unit 101, thereby forming a transmission signal. For example, if the transmission signal is an orthogonal frequency division multiplexing (OFDM) signal, the transmission processing unit 103 may map the modulated signal to the frequency resources, perform an inverse fast Fourier transform (IFFT) to convert it into a time waveform, and add a cyclic prefix (CP) to form an OFDM signal.

[0067] The transmission unit 104 may perform transmission wireless 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 processed transmission signal via an antenna.

[0068] The receiving unit 105 may perform reception wireless processing such as down-conversion and analog-to-digital (A / D) conversion on a wireless signal received via an antenna, and output the received signal after the reception wireless processing to the reception processing unit 106 .

[0069] The reception processing unit 106 can, for example, determine the resources mapped with the SRS based on the SRS setting information input from the control unit 101, and extract the signal components mapped to the determined resources from the received signal. For example, in the case of aperiodic SRS transmission, the reception processing unit 106 can receive the SRS in a time slot obtained by adding the time slot offset set in the SRS resource set (resource set(s)) to the DCI transmission timing. In addition, for example, in the case of semi-persistent SRS transmission or periodic SRS transmission, the reception processing unit 106 can periodically receive the SRS in a time slot determined by the transmission period and time slot offset set in the SRS resource set. In addition, the reception processing unit 106 can, for example, determine the frequency resource of the SRS based on the information on the transmission frequency band of the SRS resource contained in the SRS setting information.

[0070] The reception processing unit 106 may output the SRS to the reference signal receiving unit 107 , for example.

[0071] The reference signal receiving unit 107 may measure (or estimate) the reception quality (eg, channel quality) of each frequency resource based on the SRS input from the reception processing unit 106, for example, and output information related to the reception quality.

[0072] [Structure of the terminal]

[0073] Figure 6 1 is a block diagram showing a configuration example of a terminal 200 according to one embodiment of the present disclosure. Figure 6 In the embodiment, the terminal 200 may include, for example, a receiving unit 201, a receiving processing unit 202, a controlling unit 203, a reference signal generating unit 204, a transmitting processing unit 205, and a transmitting unit 206.

[0074] The receiving unit 201 may perform reception wireless processing such as down-conversion and analog-to-digital (A / D) conversion on a wireless signal received via an antenna, and output the received signal after the reception wireless processing to the reception processing unit 202 .

[0075] The reception processing unit 202 may, for example, extract SRS configuration information included in the received signal input from the reception unit 201 and output it to the control unit 203. Furthermore, when the received signal is an OFDM signal, the reception processing unit 202 may, for example, perform CP removal processing and Fourier transform (FFT) processing.

[0076] The control unit 203 can, for example, control the transmission of the SRS based on the SRS setting information input from the reception processing unit 202. For example, when the SRS transmission timing is detected from the SRS setting information, the control unit 203 determines the SRS resource set used to transmit the SRS based on the SRS setting information. Then, the control unit 203 can, for example, extract the SRS resource information applied to the SRS (for example, including the transmission bandwidth, the number of transmission combs, and the frequency hopping mode) based on the determined SRS resource set, and output (or instruct or set) it to the reference signal generation unit 204 and the transmission processing unit 205. In addition, in the case of non-periodic SRS transmission, the control unit 203 can, for example, detect the SRS transmission timing based on the SRS setting information and DCI (for example, trigger information).

[0077] For example, upon receiving a reference signal generation instruction from the control unit 203 , the reference signal generation unit 204 may generate a reference signal (eg, SRS) based on the SRS resource information input from the control unit 203 and output the reference signal to the transmission processing unit 205 .

[0078] The transmission processing unit 205 may, for example, map the SRS input from the reference signal generation unit 204 to the frequency resource indicated by the control unit 203. This forms a transmission signal. Furthermore, if the transmission signal is an OFDM signal, the transmission processing unit 205 may, for example, perform IFFT processing on the signal mapped to the frequency resource and add a CP.

[0079] The transmission unit 206 may perform transmission radio processing such as up-conversion and digital-to-analog (D / A) conversion on the transmission signal generated in the transmission processing unit 205, and transmit the signal after the transmission radio processing via an antenna.

[0080] [Operations of Base Station 100 and Terminal 200]

[0081] An operation example of the base station 100 and the terminal 200 having the above configuration will be described.

[0082] Figure 7 This is a sequence diagram showing an operation example of the base station 100 and the terminal 200 .

[0083] The base station 100 performs, for example, SRS-related configuration for the terminal 200 ( S101 ). For example, the base station 100 may generate SRS configuration information related to SRS configuration.

[0084] The base station 100 may, for example, use higher layer signaling (e.g., RRC layer signaling) to transmit (or set or notify) SRS configuration information to the terminal 200 (S102). In addition, for example, in the case of aperiodic SRS transmission, the base station 100 may also use DCI to transmit trigger information (not shown) to the terminal 200.

[0085] Terminal 200 generates an SRS based on the SRS setting information transmitted from base station 100 (S103), and transmits the generated SRS to base station 100 (S104). Base station 100 receives the SRS from terminal 200 based on the SRS setting information transmitted to terminal 200, for example.

[0086] [How to set the SRS transmission frequency band]

[0087] An example of a method for setting the transmission band of the SRS resources included in the SRS setting information (for example, an SRS resource set) in the base station 100 (for example, the control unit 101 ) will be described.

[0088] In this embodiment, for example, the upper limit of the number of transmission combs that can be set for an SRS (in other words, the frequency interval at which the SRS is configured) in a certain transmission bandwidth (e.g., a transmission bandwidth less than a threshold (e.g., 4 RBs)) can be set to be lower than the upper limit of the number of transmission combs that can be set for an SRS in a transmission bandwidth wider than the certain transmission bandwidth (e.g., a transmission bandwidth greater than the threshold). In other words, for an SRS (e.g., a narrowband SRS) configured in a transmission bandwidth less than a certain threshold (e.g., 4 RBs), the upper limit of the number of transmission combs that can be set (or used) for each transmission bandwidth can be limited.

[0089] Figure 8 This is a diagram showing a setting example of the number of available transmission combs per SRS transmission bandwidth.

[0090] exist Figure 8 For example, for an SRS with an SRS transmission bandwidth of 4 RB or more, the number of transmission combs may be any one of 2, 4, and 8 (for example, the upper limit of the number of transmission combs is 8).

[0091] On the other hand, Figure 8For example, for an SRS with an SRS transmission bandwidth less than 4 RB, the upper limit of the number of available transmission combs can be set (in other words, limited) to a value smaller than that for an SRS with an SRS transmission bandwidth greater than 4 RB. For example, the upper limit of the number of available transmission combs for an SRS with an SRS transmission bandwidth less than 4 RB can be set based on the SRS transmission bandwidth.

[0092] For example, in Figure 8 In the case where the transmission bandwidth of SRS is 2 RB, the number of transmission combs can be either 2 or 4 (for example, the upper limit of the number of transmission combs is 4). Figure 8 In the case where the transmission bandwidth of SRS is 1 RB, the number of Combs to be transmitted = 2 (for example, the upper limit of the number of Combs to be transmitted: 2) can be used. For example, Figure 8 As shown, the narrower the SRS transmission bandwidth is, the smaller the upper limit of the number of available transmission combs is.

[0093] For example, Figure 2 Or as shown in formula (1), for each SRS transmission bandwidth, the greater the number of sent combs, the shorter the sequence length of the SRS generation sequence. Figure 8 As shown, the narrower the SRS transmission bandwidth, the smaller the upper limit of the number of available transmission combs is set. This can suppress the decrease in the lower limit of the sequence length of the SRS generation sequence. This can prevent the sequence length from falling below a certain threshold, even when the SRS transmission bandwidth is less than a threshold. In other words, even when the SRS transmission bandwidth is less than a threshold, the lower limit of the sequence length can be maintained above a certain threshold.

[0094] Figure 9 This is a diagram showing an example of the relationship between the SRS transmission bandwidth, the number of transmission combs, and the sequence length. Figure 9 As an example, the SRS transmission bandwidth and the number of transmission combs can have the same Figure 8 The same relationship as shown in Figure 9 As shown in FIG, the lower limit of the SRS generation sequence length corresponding to the SRS transmission bandwidth of 2RB or 1RB less than the threshold value (for example, 4RB) is 6[sc]. In other words, Figure 9 In the embodiment, even if the SRS transmission bandwidth is smaller than a threshold value (e.g., 4RB) such as 2RB or 1RB, the lower limit value of the sequence length for SRS generation (e.g., 6[sc]) can be maintained the same as that of the SRS transmission bandwidth is greater than the threshold value such as 4RB.

[0095] This can, for example, suppress the increase in cross-correlation (or interference) between SRSs caused by the sequence length of the SRS generation sequence (in other words, the number of sequences that can be generated), and suppress the degradation of SRS channel estimation accuracy. In other words, by maintaining the lower limit of the sequence length above a certain threshold, for example, more sequences with good PAPR characteristics or cross-correlation characteristics can be generated. Therefore, according to this embodiment, for example, by increasing the number of transmitted combs for the SRS, it is possible to suppress the degradation of channel estimation accuracy using the SRS and increase the SRS transmission power density, thereby improving SRS coverage performance.

[0096] In addition, in this embodiment, although Figure 8 and Figure 9 The example in which the lower limit of the sequence length for SRS generation is set to 6 [sc] is described, but the lower limit of the sequence length is not limited to 6 [sc]. For example, the upper limit of the number of transmitted combs is not limited to Figure 8 or Figure 9 The value shown. Figure 10 and Figure 11 This is a diagram showing another example of the relationship between the SRS transmission bandwidth, the number of transmission combs, and the sequence length. Figure 10 For example, for an SRS transmission bandwidth less than 4 RB, the upper limit of the number of available transmission combs can be set to Figure 8 Thus, for example, Figure 11 As shown, the lower limit of the sequence length for SRS generation is set to (in other words, maintained at) Figure 9 More 12[sc]. Thus, in Figure 10 and Figure 11 For example, Figure 8 and Figure 9 Compared with the case of , it is easier to use SRS with a long sequence length, so the channel estimation accuracy based on SRS can be improved.

[0097] In addition, in this embodiment, although Figures 8 to 10 The number of subcarriers per RB in formula (1) is 12 (N sc RB =12), but the number of subcarriers per RB is not limited to 12 [sc / RB]. For example, when the number of subcarriers per RB is 6 [sc / RB], the sequence length is Figure 9 、 Figure 11 The upper limit of the number of available send combs is 1 / 2 of the sequence length shown. Figure 8 、 Figure 10 Halved.

[0098] (Implementation Method 2)

[0099] In this embodiment, an example of frequency hopping of an SRS (for example, a narrowband SRS) arranged in a transmission bandwidth smaller than a certain threshold (for example, 4 RBs) will be described.

[0100] [Frequency Hopping of Narrowband SRS]

[0101] As described above, for example, the minimum transmission bandwidth of NR SRS may be 4 RB, and the transmission bandwidth of SRS may be a multiple of 4. In addition, by performing N (N is an integer) frequency hopping on the narrowband SRS, the narrowband SRS may be transmitted in a detection band that is N times the transmission bandwidth.

[0102] For example, it is also conceivable that future NRs support SRS transmission with a bandwidth less than 4 RB (e.g., 2 RB or 1 RB). In this case, if a frequency hopping pattern with a granularity of 2 RB or 1 RB is applied, a conflict between the SRS and the frequency hopping pattern with a granularity of 4 RB will occur.

[0103] Figure 12 is a diagram showing an example of a frequency hopping pattern. Figure 12 As an example, a frequency hopping pattern with a granularity of 2RB (in other words, in units of 2RB) is set for the SRS sent by UE#0, and a frequency hopping pattern with a granularity of 4RB (in other words, in units of 4RB) is set for the SRS sent by UE#1. Figure 12 For example, there is a case where a collision occurs between the SRSs transmitted from UE#0 and UE#1 at at least a portion of their respective SRS transmission timings.

[0104] Due to the collision of SRSs, interference between SRSs occurs, and thus the accuracy of channel estimation based on SRSs deteriorates.

[0105] Therefore, in this embodiment, a setting example of the frequency hopping pattern of the narrowband SRS will be described.

[0106] The configuration examples of the base station and the terminal in this embodiment may differ from those in the first embodiment in some functions, but may be the same as those in the first embodiment in other functions.

[0107] [Structure of base station]

[0108] In the base station 100 of this embodiment, the control unit 101 can, for example, set the frequency hopping pattern for the SRS allocated to each transmission bandwidth. For example, the control unit 101 can set a frequency hopping pattern that prevents frequency resource conflicts between the frequency hopping pattern applied to an SRS with a transmission bandwidth less than a threshold (e.g., a narrowband SRS) and the frequency hopping pattern applied to an SRS with a transmission bandwidth greater than the threshold (e.g., a narrowband SRS). The control unit 101 can, for example, output SRS configuration information including the set frequency hopping pattern to the coding / modulation unit 102 and the reception processing unit 106.

[0109] The receiving processing unit 106 can, for example, determine the resources mapped with the SRS based on the SRS setting information (for example, including the frequency hopping mode) input from the control unit 101, and extract the signal component (for example, SRS) mapped to the determined resource from the received signal input from the receiving unit 105.

[0110] Other processes in base station 100 may be the same as those in embodiment 1.

[0111] [Structure of the terminal]

[0112] The terminal 200 of this embodiment can, for example, map the SRS to the resources instructed to transmit the SRS based on the SRS setting information (for example, including the frequency hopping pattern) from the base station 100 and transmit the SRS.

[0113] [Example of Setting the Frequency Hopping Pattern of Narrowband SRS]

[0114] A description will be given of a setting example of a frequency hopping pattern applied to SRS resources included in SRS setting information (for example, an SRS resource set) generated in the base station 100 (for example, the control unit 101 ).

[0115] In this embodiment, for example, in a frequency hopping mode of a narrowband SRS configured in a transmission bandwidth smaller than a threshold value (e.g., 4 RB), the SRS can be transmitted in a portion of the transmission band set according to the frequency hopping mode of the SRS configured in the transmission bandwidth smaller than a threshold value (e.g., 4 RB).

[0116] For example, the base station 100 and the terminal 200 may control the frequency hopping of the SRS having a transmission bandwidth smaller than the threshold value in units of the transmission band (eg, 4 RB) of the SRS having a transmission bandwidth as the threshold value configured in each time slot.

[0117] Hereinafter, examples 1 and 2 of frequency hopping pattern setting will be described.

[0118] <Example 1>

[0119] Figure 13 and Figure 14 This is a diagram showing an example of setting a frequency hopping pattern of a narrow-band SRS.

[0120] exist Figure 13 and Figure 14 In the present invention, the base station 100 and the terminal 200 can, for example, control the frequency hopping (for example, frequency hopping between time slots) of a narrow-band SRS (for example, the SRS of UE#0) having a transmission bandwidth smaller than a threshold value (for example, 4RB) by taking the transmission band of the SRS configured in the transmission bandwidth corresponding to the threshold as a unit (for example, in units of 4RB).

[0121] In addition, Figure 13 and Figure 14 For example, in a frequency hopping mode of a narrowband SRS with a transmission bandwidth less than a threshold (for example, 4RB) (for example, a frequency hopping mode set for UE#0), the base station 100 and the terminal 200 can control the frequency hopping between multiple SRS code elements configured in the SRS within the time slot.

[0122] For example, in Figure 13 In the example, a frequency hopping pattern with a granularity of 2 RB (in other words, a transmission bandwidth less than a threshold) is set for the SRS sent by UE#0, and a frequency hopping pattern with a granularity of 4 RB (in other words, a transmission bandwidth greater than a threshold) is set for the SRS sent by UE#1. Figure 13 For example, a narrowband SRS of 2 RB can be configured in 2 symbols in a time slot and frequency hopped in a 4 RB band in the time slot. Figure 13 As shown, the SRS allocated in the two symbols in each time slot can be frequency-hopped between time slots in units of 4 RBs.

[0123] In addition, for example, Figure 14 In the example, a frequency hopping pattern with a granularity of 1 RB (in other words, a transmission bandwidth less than a threshold) is set for the SRS sent by UE#0, and a frequency hopping pattern with a granularity of 4 RB (in other words, a transmission bandwidth greater than a threshold) is set for the SRS sent by UE#1. Figure 14 For example, a narrowband SRS of 1 RB can be configured in 4 symbols in a time slot and frequency hopped in the 4 RB frequency band in the time slot. Figure 14 As shown, the SRS in the 4 symbols allocated in each time slot can be frequency-hopped between time slots in units of 4 RBs.

[0124] exist Figure 13 and Figure 14 In the example, the 4RB frequency band for frequency hopping within a time slot (in other words, the frequency hopping unit for frequency hopping between time slots) may be one of the frequency bands determined based on the frequency hopping pattern of the NR SRS (or the SRS with a transmission bandwidth corresponding to the threshold). Figure 13 and Figure 14As shown, the total transmission bandwidth (e.g., 4 RB) of multiple SRSs configured for frequency hopping between symbols in a time slot of UE#0 is the same as the transmission bandwidth (e.g., 4 RB) of SRSs configured in each time slot of UE#1. Figure 13 and Figure 14 As shown, in each time slot, the transmission frequency band in which the SRS of UE#0 is allocated may be different from the transmission frequency band in which the SRS of UE#1 is allocated.

[0125] By setting this frequency hopping pattern, for example, the frequency hopping pattern for narrowband SRS with a transmission bandwidth less than a threshold (e.g., 4 RBs) and the frequency hopping pattern for narrowband SRS with a transmission bandwidth greater than the threshold (e.g., 4 RBs) are orthogonally multiplexed in the frequency domain. Therefore, even when frequency hopping patterns with different granularities are applied to different terminals 200, SRS collisions can be suppressed.

[0126] In addition, for example, for a narrowband SRS with a transmission bandwidth smaller than a threshold (e.g., 4 RB), frequency hopping is applied between symbols within a time slot, thereby reducing the frequency hopping period (or frequency hopping cycle). Figure 13 and Figure 14 In the example, the frequency hopping period of the SRS with a transmission bandwidth less than the threshold is 4 time slots.

[0127] In addition, Figure 13 and Figure 14 In the embodiment, the following pattern is described as an example of frequency hopping between symbols within a time slot, where the SRS of a later symbol in the time domain is allocated to a higher frequency band in the frequency domain. However, the frequency hopping pattern between symbols within a time slot is not limited to this.

[0128] <Example 2>

[0129] Figure 15 This is a diagram showing an example of setting a frequency hopping pattern of a narrow-band SRS.

[0130] exist Figure 15 In the example, the base station 100 and the terminal 200 control the frequency hopping of the narrowband SRS (for example, the SRS of UE#0) having a transmission bandwidth smaller than the threshold (for example, 4 RB) according to the frequency hopping period (for example, by time slot) of the SRS having a transmission bandwidth corresponding to the threshold (for example, 4 RB). In addition, Figure 15 As shown, in the frequency hopping mode of a narrow-band SRS with a transmission bandwidth less than a threshold (e.g., 4RB) (e.g., the frequency hopping mode for UE#0), the SRS can be frequency-hopped in units of the transmission band of the SRS with a transmission bandwidth corresponding to the threshold (e.g., the SRS of UE#1) (e.g., in units of 4RB).

[0131] For example, in Figure 15In the example, a frequency hopping pattern with a granularity of 2 RB (in other words, a transmission bandwidth less than a threshold) is set for the SRS sent by UE#0, and a frequency hopping pattern with a granularity of 4 RB (in other words, a transmission bandwidth greater than a threshold) is set for the SRS sent by UE#1. Figure 15 For example, a narrowband SRS of 2 RB can be configured in 1 symbol within a time slot and frequency-hopped between time slots in units of 4 RB (for example, in units of the same transmission frequency band as the SRS of UE#1).

[0132] like Figure 15 As shown, the frequency hopping period (or frequency hopping cycle) of the 2RB narrowband SRS is 8 time slots.

[0133] Furthermore, for example, a frequency hopping pattern can be similarly set for an SRS (not shown) having a transmission bandwidth of 1 RB. The frequency hopping period of the narrowband SRS of 1 RB is, for example, 16 slots.

[0134] exist Figure 15 In the example, the 4RB frequency band (in other words, the frequency hopping unit of the frequency hopping between time slots) for frequency hopping of the SRS with a transmission bandwidth smaller than the threshold value may be one of the frequency bands determined based on the frequency hopping pattern of the NR SRS (or the SRS with a transmission bandwidth corresponding to the threshold value). Figure 15 As shown, in each time slot, the transmission frequency band in which the SRS of UE#0 is allocated may be different from the transmission frequency band in which the SRS of UE#1 is allocated.

[0135] By setting this frequency hopping pattern, for example, the frequency hopping pattern for narrowband SRS with a transmission bandwidth less than a threshold (e.g., 4 RBs) and the frequency hopping pattern for narrowband SRS with a transmission bandwidth greater than the threshold (e.g., 4 RBs) are orthogonally multiplexed in the frequency domain. Therefore, even when frequency hopping patterns with different granularities are applied to different terminals 200, SRS collisions can be suppressed.

[0136] For example, compare Example 1 with Example 2.

[0137] In Example 1, the frequency hopping period of the SRS having a transmission bandwidth smaller than the threshold may be set shorter than Ratio 2. In other words, in Example 1, the same frequency hopping period as that of the SRS having a transmission bandwidth greater than the threshold may be maintained.

[0138] On the other hand, in Example 2, the amount of SRS resources allocated in each time slot can be reduced compared to Example 1.

[0139] An example of setting the frequency hopping pattern of the narrow-band SRS has been described above.

[0140] In this embodiment, in the frequency hopping pattern for a narrowband SRS with a transmission bandwidth less than a threshold (e.g., 4 RBs), the SRS is transmitted within at least a portion of the transmission bandwidth configured based on the frequency hopping pattern for the SRS with a transmission bandwidth corresponding to the threshold (e.g., 4 RBs). In other words, the frequency hopping pattern for the narrowband SRS with a transmission bandwidth less than the threshold can reuse the settings (in other words, the mechanism, e.g., the frequency hopping unit) of the frequency hopping pattern for the SRS with a transmission bandwidth corresponding to the threshold.

[0141] Thus, in this embodiment, the frequency hopping pattern for narrowband SRSs with a transmission bandwidth less than a threshold and the frequency hopping pattern for narrowband SRSs with a transmission bandwidth greater than the threshold enable orthogonal multiplexing of SRSs in the frequency domain, thereby suppressing the occurrence of collisions between SRSs. Thus, according to this embodiment, interference between SRSs can be suppressed, and the accuracy of channel estimation based on SRSs can be improved.

[0142] In the above, one embodiment of the present disclosure has been described.

[0143] In addition, in one embodiment of the present disclosure, although the case of setting SRS setting information for the terminal 200 using high-layer signaling (for example, RRC layer signaling) is described, the setting of the SRS setting information is not limited to high-layer signaling, and can also be other signaling (for example, physical layer signaling).

[0144] In addition, in one embodiment of the present disclosure, the object for notifying resources such as transmission bandwidth and the number of transmission combs is not limited to reference signals such as SRS, but may also be other signals (or information). For example, instead of SRS, one embodiment of the present disclosure may also be applied to response signals to data (e.g., also known as "ACK (Acknowledgement) / NACK (Negative Acknowledgement)" or "HARQ-ACK (Hybrid Automatic Repeat reQuest-Acknowledgement)").

[0145] In addition, in one embodiment of the present disclosure, parameters such as candidate SRS resources (e.g., a combination of transmission bandwidth, number of transmission combs, and sequence length), a threshold (e.g., 4RB), an upper limit value of the number of transmission combs, or a granularity of frequency hopping (e.g., 1RB, 2RB, or 4RB), and the number of subcarriers per RB are not limited to the above examples and may also be other values.

[0146] (Control Signal)

[0147] In one embodiment of the present disclosure, a downlink control signal (or downlink control information) may be, for example, a signal (or information) transmitted via the physical downlink control channel (PDCCH) at the physical layer, or a signal (or information) transmitted via the media access control (MAC) or radio resource control (RRC) at a higher layer. Furthermore, the signal (or information) is not limited to being notified via a downlink control signal and may be pre-defined in a specification (or standard) or pre-configured in a base station or terminal.

[0148] 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 the PDCCH of the physical layer, or a signal (or information) transmitted in the MAC or RRC of a higher layer. Furthermore, the signal (or information) is not limited to being notified by the uplink control signal, and may be pre-specified in the specification (or standard), or may be pre-set in the base station and the terminal. Furthermore, the uplink control signal may be, for example, replaced with uplink control information (UCI), first stage sidelink control information (SCI), or second stage SCI.

[0149] (Base Station)

[0150] In one embodiment of the present disclosure, a base station may also be a Transmission Reception Point (TRP), a cluster head, an access point, a Remote Radio Head (RRH), an eNodeB (eNB), a gNodeB (gNB), a Base Station (BS), a Base Transceiver Station (BTS), a master station, a gateway, or the like. Furthermore, in sidelink communications, a terminal may replace the base station. Furthermore, a relay device that relays communications between the terminal and a higher-level node may replace the base station.

[0151] (Uplink / Downlink / Sidelink)

[0152] An embodiment of the present disclosure can be applied to any link in the uplink, downlink, and sidelink. For example, an embodiment of the present disclosure can also be applied to the physical uplink shared channel (PUSCH), physical uplink control channel (PUCCH), physical random access channel (PRACH) of the uplink, the physical downlink shared channel (PDSCH), PDCCH, physical broadcast channel (PBCH) of the downlink, or the physical sidelink shared channel (PSSCH), physical sidelink control channel (PSCCH), physical sidelink broadcast channel (PSBCH) of the sidelink.

[0153] In addition, PDCCH, PDSCH, PUSCH, and PUCCH are examples of downlink control channels, downlink data channels, uplink data channels, and uplink control channels, respectively. In addition, PSCCH and PSSCH are examples of sidelink control channels and sidelink data channels, respectively. In addition, PBCH and PSBCH are examples of broadcast channels, and PRACH is an example of a random access channel.

[0154] (Data channel / Control channel)

[0155] An embodiment of the present disclosure can be applied to any of the data channels and control channels. For example, the channel in an embodiment of the present disclosure can be replaced with one of the data channels PDSCH, PUSCH, PSSCH, or the control channels PDCCH, PUCCH, PBCH, PSCCH, and PSBCH.

[0156] (Reference signal)

[0157] In one embodiment of the present disclosure, a reference signal is a signal known to both the base station and the mobile station, and is sometimes referred to as a "Reference Signal (RS)" or "pilot signal." The reference signal can be any of the following: 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).

[0158] (Time interval)

[0159] In one embodiment of the present disclosure, the unit of time resources is not limited to one of a time slot and a symbol, or a combination thereof. For example, a time resource unit such as a frame, a superframe, a subframe, a time 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 other time resource units may be used. In addition, the number of symbols contained in one time slot is not limited to the number of symbols exemplified in the above embodiment, and may be other numbers of symbols.

[0160] (frequency band)

[0161] An embodiment of the present disclosure may be applied to any one of a licensed band and an unlicensed band.

[0162] (communication)

[0163] An embodiment of the present disclosure can be applied to any communication between a base station and a terminal, between terminals (sidelink communication, Uu link communication), or in vehicle-to-everything (V2X) wireless communication. For example, the channel in an embodiment of the present disclosure can be replaced with one of the following channels: PSCCH, PSSCH, Physical Sidelink Feedback Channel (PSFCH), PSBCH, PDCCH, PUCCH, PDSCH, PUSCH, or PBCH.

[0164] Furthermore, an embodiment of the present disclosure can be applied to any network, including terrestrial networks and non-terrestrial networks (NTNs) using satellites or high-altitude pseudo-satellites (HAPSs). Furthermore, an embodiment of the present disclosure can be applied to terrestrial networks with large cell sizes and transmission delays greater than the symbol length or slot length, such as ultra-wideband transmission networks.

[0165] (Antenna port)

[0166] In one embodiment of the present disclosure, an antenna port refers to a logical antenna (antenna group) composed of one or more physical antennas. For example, an antenna port does not necessarily refer to a single physical antenna, but may refer to an array antenna composed of multiple antennas. For example, an antenna port may not be defined as consisting of a number of physical antennas, but may be defined as the minimum unit by which a terminal can transmit a reference signal (reference signal). In addition, an antenna port is sometimes defined as the minimum unit by which a weighted precoding vector is multiplied.

[0167] 5G NR System Architecture and Protocol Stack

[0168] 3GPP continues to work on the next version of fifth-generation mobile technology (also known as "5G"), including the development of new radio access technology (NR) operating in the frequency range up to 100 GHz. The first version of the 5G standard was completed in late 2017, enabling the transition to trial production and commercial deployment of devices (e.g., smartphones) compliant with the 5G NR standard.

[0169] For example, the overall system architecture envisions an NG-RAN (Next Generation Radio Access Network) consisting of gNBs. The gNBs provide UE-side termination of the user plane (SDAP (Service Data Adaptation Protocol) / PDCP (Packet Data Convergence Protocol) / RLC (Radio Link Control) / MAC / PHY (Physical Layer)) and control plane (RRC) protocols of the NG radio access. gNBs are connected to each other via the Xn interface. Furthermore, gNBs are connected to the Next Generation Core (NGC) via the Next Generation (NG) interface, more specifically, to the Access and Mobility Management Function (AMF) (e.g., a core entity that implements the AMF) via the NG-C interface, and to the User Plane Function (UPF) (e.g., a core entity that implements the UPF) via the NG-U interface. Figure 16 Represents the NG-RAN architecture (for example, refer to 3GPP TS 38.300 v15.6.0, section 4).

[0170] The NR user plane protocol stack (e.g., see 3GPP TS 38.300, Section 4.4.1) includes the PDCP (Packet Data Convergence Protocol) sublayer (see Section 6.4 of TS 38.300), the RLC (Radio Link Control) sublayer (see Section 6.3 of TS 38.300), and the MAC (Media Access Control) sublayer (see Section 6.2 of TS 38.300), which terminates on the network side in the gNB. Furthermore, a new access stratum (AS) sublayer (SDAP: Service Data Adaptation Protocol) has been introduced on top of PDCP (e.g., see Section 6.5 of 3GPP TS 38.300). Furthermore, a control plane protocol stack has been defined for NR (e.g., see Section 4.4.2 of TS 38.300). An overview of Layer 2 functionality is provided 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.

[0171] For example, the media access control layer handles multiplexing of logical channels, scheduling including processing of various parameter sets, and various functions associated with the scheduling.

[0172] For example, the physical layer (PHY) is responsible for coding, PHY HARQ (Physical Layer Hybrid Automatic Repeat Request) processing, modulation, multi-antenna processing, and mapping signals to appropriate physical time-frequency resources. In addition, the physical layer handles the mapping of transport channels to physical channels. The physical layer provides services to the MAC layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used to send a specific transport channel, and each transport channel is mapped to a corresponding physical channel. For example, among physical channels, uplink physical channels include PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel), and downlink physical channels include PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), and PBCH (Physical Broadcast Channel).

[0173] NR use cases and extension scenarios include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), all of which have various requirements for data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps in the downlink and 10 Gbps in the uplink) and effective (user-experienced) data rates that are approximately three times higher than those provided by IMT-Advanced (International Mobile Telecommunications-Advanced). Meanwhile, URLLC imposes stricter requirements for ultra-low latency (0.5 ms for the user plane in both the UL and DL) and high reliability (1-10-5 within 1 ms). Finally, in mMTC, preferably high connection density (1,000,000 devices / km2 in urban environments), large coverage in harsh environments, and very long battery life (15 years) for cheap devices are required.

[0174] Therefore, sometimes the OFDM parameter set (e.g., subcarrier spacing (SCS), OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) that is suitable for one use case is not valid for other use cases. For example, in low-latency services, it is preferred that the symbol length is shorter than that of mMTC services (therefore, the subcarrier spacing is larger) and / or the number of symbols per scheduling interval (also known as "TTI (Transmission Time Interval)") is smaller. Moreover, in extended scenarios where the channel delay spread is large, it is preferred that the CP length is longer than that in scenarios where the delay spread is short. The subcarrier spacing can also be optimized according to the situation to maintain the same CP overhead. The subcarrier spacing supported by NR can have more than one value. Correspondingly, subcarrier spacings of 15kHz, 30kHz, 60kHz... are currently considered. The symbol length Tu and the subcarrier spacing Δf are directly related according to the formula Δf=1 / Tu. Similar to the LTE system, the term “resource element” can be used to represent the minimum resource unit consisting of one subcarrier with a length of one OFDM / SC-FDMA (Single-Carrier Frequency Division Multiple Access) symbol.

[0175] In the new wireless system 5G-NR, a resource grid of subcarriers and OFDM symbols is defined for each numerology set and each carrier in both the uplink and downlink. Each element of the resource grid is called a "resource element" and is identified by a frequency index in the frequency domain and a symbol position in the time domain (see 3GPP TS 38.211 v15.6.0).

[0176] Functional separation between NG-RAN and 5GC in 5G NR

[0177] Figure 17 This indicates the functional separation between NG-RAN and 5GC. The logical node of NG-RAN is the gNB or ng-eNB. The 5GC has the logical nodes AMF, UPF, and SMF (Session Management Function).

[0178] For example, gNB and ng-eNB host the following key functions:

[0179] - Radio bearer control (RBC), radio admission control (RAC), connection mobility control (CMC), and radio resource management (RRM) functions, such as dynamically allocating (scheduling) resources to UEs in both uplink and downlink;

[0180] - IP (Internet Protocol) header compression, encryption, and integrity protection of data;

[0181] - Selection of the AMF upon attaching the UE in case the routing towards the AMF cannot be decided based on the information provided by the UE;

[0182] - Routing of user plane data towards the UPF;

[0183] - Routing of control plane information towards the AMF;

[0184] -Setting up and disconnecting connections;

[0185] - Scheduling and sending of paging messages;

[0186] - Scheduling and sending of system broadcast information (AMF or Operation, Admission, Maintenance (OAM) function as the originator);

[0187] - Settings for measurements and measurement reports for mobility and scheduling;

[0188] - Packet marking of transmission class in uplink;

[0189] -Session management;

[0190] - Network slicing support;

[0191] -QoS (Quality of Service) flow management and mapping to data radio bearers;

[0192] - Support for UEs in RRC_INACTIVE (RRC inactive) state;

[0193] -NAS (Non Access Stratum) message distribution function;

[0194] -Sharing of wireless access networks;

[0195] -Dual connection;

[0196] -Close collaboration between NR and E-UTRA (Evolved Universal Terrestrial Radio Access).

[0197] The Access and Mobility Management Function (AMF) hosts the following main functions:

[0198] - Functionality to terminate Non-Access Stratum (NAS) signaling;

[0199] -Security of NAS signaling;

[0200] -Security control of the access layer (AS);

[0201] -Core Network (CN) inter-node signaling for mobility between 3GPP access networks;

[0202] - the possibility of reaching the UE in idle mode (including the control and execution of paging retransmission);

[0203] - Management of the registration area;

[0204] -Support for intra-system and inter-system mobility;

[0205] -Access authentication;

[0206] - Access permission including roaming permission check;

[0207] -Mobility management control (subscription and policy);

[0208] - Network slicing support;

[0209] - Selection of Session Management Function (SMF).

[0210] In addition, the User Plane Function (UPF) hosts the following main functions:

[0211] - Anchor point for intra-RAT (Radio Access Technology) mobility / inter-RAT (Inter-RAT) mobility (where applicable);

[0212] - External PDU (Protocol Data Unit) session point for interconnection with data networks;

[0213] -Packet routing and forwarding;

[0214] - Packet inspection and policy rule enforcement in the user plane;

[0215] - Business usage reports;

[0216] - Uplink classifier for supporting routing of traffic towards the data network;

[0217] -BranchingPoint used to support multi-homed PDU session;

[0218] - QoS processing for the user plane (e.g., packet filtering, gating, UL / DL rate enforcement);

[0219] - Verification of uplink services (mapping of SDF (Service Data Flow) to QoS flows);

[0220] - Downlink packet buffering and downlink data notification triggering function.

[0221] Finally, the Session Management Function (SMF) hosts the following main functions:

[0222] -Session management;

[0223] -Allocation and management of UE IP addresses;

[0224] - UPF selection and control;

[0225] - Traffic steering configuration function in the user plane function (UPF) for directing traffic to the appropriate destination;

[0226] - Enforcement of policies and QoS in the control part;

[0227] -Notification of downlink data.

[0228] <RRC connection setup and re-setup process>

[0229] Figure 18 Represents several interactions between the UE, gNB and AMF (5GC entity) when the NAS part of the UE transitions from RRC_IDLE (RRC Idle) to RRC_CONNECTED (RRC Connected) (refer to TS 38.300v15.6.0).

[0230] RRC is a high-layer signaling (protocol) used for the configuration of the UE and gNB. Through this transition, the AMF prepares UE context data (including, for example, PDU session context, security keys, UE radio capabilities, UE security capabilities, etc.) and sends it to the gNB along with the initial context setup request (INITIAL CONTEXT SETUP REQUEST). Next, the gNB and the UE activate AS security. The gNB sends a SecurityModeCommand message to the UE, and the UE responds to the gNB with a SecurityModeComplete message, thereby activating AS security. The gNB then sends an RRCReconfiguration message to the UE, and the gNB receives an RRCReconfigurationComplete message from the UE in response to the RRCReconfiguration message, thereby reconfiguring the Signaling Radio Bearer 2 (SRB2) and Data Radio Bearer (DRB). For signaling-only connections, since SRB2 and DRB are not configured, the steps related to RRC reconfiguration can be omitted. Finally, the gNB notifies the AMF of the completion of the setup process using the Initial Context Setup Response (INITIAL CONTEXT SETUP RESPONSE).

[0231] Therefore, the present disclosure provides the following fifth-generation core network (5GC) entity (e.g., AMF, SMF, etc.), which includes: a control circuit that, when operating, establishes a next-generation (NG) connection with a gNodeB; and a transmitter that, when operating, sends an initial context setup message to the gNodeB via the NG connection to set up a signaling radio bearer between the gNodeB and a user equipment (UE). Specifically, the gNodeB sends radio resource control (RRC) signaling including a resource allocation setup information element (IE) to the UE via the signaling radio bearer. The UE then transmits in the uplink or receives in the downlink based on the resource allocation setup.

[0232] IMT Utilization Scenarios After 2020

[0233] Figure 19Indicates several use cases for 5G NR. In the 3rd Generation Partnership Project New Radio (3GPP NR), three use cases supporting a wide range of services and applications, as envisioned by IMT-2020, have been studied. The first phase of specification development for high-capacity, high-speed communications (eMBB: enhanced mobile broadband) has been completed. Current and future work includes the gradual expansion of support for eMBB and the standardization of ultra-reliable and low-latency communications (URLLC: ultra-reliable and low-latency communications) and multi-machine-type communications (mMTC: massive machine-type communications). Figure 19 Several examples of conceptual use cases for IMT after 2020 (for example, see ITU-R M.2083) Figure 2 ).

[0234] The use cases of URLLC have strict requirements related to performance such as throughput, latency (delay) and availability. The use cases of URLLC are conceived as an element technology for realizing future applications such as wireless control of industrial production processes or manufacturing processes, remote medical surgery, automation of power transmission and distribution in smart grids, and traffic safety. The ultra-high reliability of URLLC is supported by determining technologies that meet the requirements set by TR38.913. In the NR URLLC version 15, as an important requirement, the requirement that the target user plane latency is 0.5ms in UL (uplink) and 0.5ms in DL (downlink) is included. The overall URLLC requirement for a packet transmission is a block error rate (BLER) of 1E-5 for a packet size of 32 bytes with a user plane latency of 1ms.

[0235] Considering the physical layer, there are a number of possible approaches to improve reliability. Current scope for improving reliability includes defining additional CQI (Channel Quality Indicator) tables for URLLC, more compact DCI formats, PDCCH iteration, etc. However, as NR (an important prerequisite for NR URLLC) becomes more stable and receives further development, this scope can be expanded to achieve ultra-high reliability. Specific use cases for NR URLLC in Release 15 include augmented reality / virtual reality (AR / VR), e-health, e-safety, and critical applications.

[0236] In addition, the technical enhancements to the goals of NR URLLC are aimed at improving latency and increasing reliability. Technical enhancements for improving latency include configurable parameter sets, non-slot-based scheduling with flexible mapping, unauthorized (authorized) uplinks, slot-level repetitions in data channels, and preemption in downlinks. Preemption means stopping the transmission of allocated resources and using the allocated resources for other transmissions that are requested later and must meet the necessary conditions for lower latency / higher priority. Therefore, the transmission that has been allowed will be replaced by the subsequent transmission. Preemption can be applied regardless of the specific service type. For example, the transmission of service type A (URLLC) can also be replaced by the transmission of service type B (eMBB, etc.). Technical enhancements related to improving reliability include a dedicated CQI / MCS table for a target BLER of 1E-5.

[0237] The use case for mMTC (Massive Machine Type Communications) is characterized by a typically large number of connected devices transmitting relatively small amounts of data that are less susceptible to latency. Devices are required to be low-priced and have very long battery life. From the perspective of NR, utilizing very narrow bandwidth segments is one approach to conserving UE power and extending battery life.

[0238] As mentioned above, it is predicted that the room for reliability improvement in NR will be further expanded. It is one of the important requirements for all situations. For example, the important requirement related to URLLC and mMTC is high reliability or ultra-high reliability. From the perspective of wireless and the perspective of the network, reliability can be improved in several mechanisms. In general, there are two to three important areas that may help improve reliability. These areas include compact control channel information, repetition of data channels / control channels, and diversity related to frequency domain, time domain and / or spatial domain. These areas can be used universally to improve reliability regardless of the specific communication scenario.

[0239] NR URLLC envisions further use cases with stricter requirements, such as factory automation, transportation, and power transmission. These strict requirements include high reliability (up to 10-6 reliability), high availability, packet sizes up to 256 bytes, and time synchronization of several microseconds (μs). This can be set to 1 μs or several microseconds depending on the frequency range and short latency of around 0.5 ms to 1 ms (e.g., a target latency of 0.5 ms in the user plane), depending on the use case.

[0240] Moreover, regarding NR URLLC, from the perspective of the physical layer, there may be several technical enhancements. These technical enhancements include the enhancement of PDCCH (Physical Downlink Control Channel) related to compact DCI, repetition of PDCCH, and increased monitoring of PDCCH. In addition, the enhancement of UCI (Uplink Control Information) is related to the enhancement of enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback. In addition, there may be enhancement of PUSCH related to frequency hopping at the micro-slot level and enhancement of retransmission / repetition. The term "micro-slot" refers to a transmission time interval (TTI) that contains fewer code elements than a time slot (a time slot has 14 code elements).

[0241] QoS Control

[0242] The 5G QoS (Quality of Service) model is based on QoS flows, supporting both QoS flows that require guaranteed bit rates (GBR: Guaranteed Bit Rate QoS flows) and QoS flows that do not (non-GBR QoS flows). Therefore, at the NAS level, a QoS flow is the most granular QoS division within a PDU session. A QoS flow is identified within a PDU session by the QoS Flow ID (QFI: QoS Flow ID) transmitted in the encapsulation header via the NG-U interface.

[0243] For each UE, 5GC establishes one or more PDU sessions. For each UE, in conjunction with the PDU session, NG-RAN, for example, as described in the previous reference Figure 18 As described, at least one data radio bearer (DRB) is established. Additionally, DRBs added to the QoS flows of this PDU session may be configured later (when this is configured depends on 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 are used to associate UL and DL packets with QoS flows, and AS-level mapping rules in the UE and NG-RAN associate UL and DL QoS flows with DRBs.

[0244] Figure 20 Indicates the non-roaming reference architecture of 5G NR (refer to TS23.501v16.1.0, section 4.23). Application Function (AF) (e.g., host Figure 19The external application server of the 5G service illustrated in the example interacts with the 3GPP core network to provide services. For example, the network exposure function (NEF) is accessed to support applications that affect the routing of the service, or the policy framework is interacted with for policy control (for example, QoS control) (see Policy Control Function (PCF)). Based on the operator's deployment, the operator considers that the application function that is trusted can interact directly with the associated network function (Network Function). Application functions that are not allowed by the operator to directly access the network function interact with the associated network function via the NEF using a release framework for the outside.

[0245] Figure 20 It also represents further functional units of the 5G architecture, namely, the Network Slice Selection Function (NSSF), the Network Repository Function (NRF), the Unified Data Management (UDM), the Authentication Server Function (AUSF), the Access and Mobility Management Function (AMF), the Session Management Function (SMF), and the Data Network (DN, e.g., services provided by an operator, Internet access, or services provided by a third party). All or part of the core network functions and application services may also be deployed and operated in a cloud computing environment.

[0246] Therefore, the present disclosure provides the following application server (for example, AF of 5G architecture), which includes: a sending unit, which, in action, sends a request containing QoS requirements for at least one of URLLC service, eMMB service and mMTC service to at least one function of 5GC (for example, NEF, AMF, SMF, PCF, UPF, etc.) in order to establish a PDU session of wireless bearer between g-node B and UE corresponding to QoS requirements; and a control circuit, which, in action, uses the established PDU session to provide service.

[0247] The present disclosure can be implemented by software, hardware, or software in collaboration with hardware. The functional blocks used in the description of the above embodiments are partially or entirely implemented as LSIs (Large Scale Integration) as integrated circuits, and the various processes described in the above embodiments may also be partially or entirely controlled by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip in a manner that includes part or all of the functional blocks. The LSI may also include data input and output. Depending on the degree of integration, the LSI may also be referred to as an "IC (Integrated Circuit)", "System LSI", "Super LSI", or "Ultra LSI".

[0248] Integrated circuit implementation is not limited to LSIs and can also be implemented using dedicated circuits, general-purpose processors, or dedicated processors. Alternatively, an FPGA (Field Programmable Gate Array) that can be programmed after LSI fabrication, or a reconfigurable processor that can reconfigure the connections and settings of circuit blocks within the LSI, can be utilized. The present disclosure can also be implemented as digital processing or analog processing.

[0249] Furthermore, if semiconductor technology advances or other technologies evolve and a technology for integrated circuits emerges that replaces LSIs, it would be possible to use this technology to integrate functional blocks. There is also the possibility of applying biotechnology, etc.

[0250] The present disclosure can be implemented in all kinds of devices, equipment, and systems (collectively referred to as "communication devices") with communication functions. The communication device may also include a wireless transceiver and a processing / control circuit. The wireless transceiver may also include a receiving unit and a transmitting unit, or perform the functions of these parts. The wireless transceiver (transmitting unit, receiving unit) may also include an RF (Radio Frequency) module and one or more antennas. The RF module may also include an amplifier, an RF modulator / demodulator, or devices similar to these. Non-limiting examples of communication devices include: telephones (mobile phones, smartphones, etc.), tablet computers, personal computers (PCs) (laptops, desktops, notebook computers, etc.), cameras (digital cameras, digital video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smart watches, tracking devices, etc.), game consoles, e-book readers, telehealth / telemedicine (telehealth / medical prescription) equipment, vehicles with communication functions or transportation vehicles (cars, airplanes, ships, etc.), and combinations of the above devices.

[0251] Communication devices are not limited to portable or mobile devices. They also include all types of devices, equipment, and systems that cannot be portable or fixed. Examples include smart home devices (appliances, lighting, smart meters or meters, control panels, etc.), vending machines, and all other "things" that can exist on an IoT (Internet of Things) network.

[0252] The communication includes data communication performed by a cellular system, a wireless LAN (Local Area Network) system, a communication satellite system, etc., and also includes data communication performed by a combination of these systems.

[0253] Furthermore, the communication device also includes devices such as controllers and sensors that are connected or coupled to the communication equipment performing the communication functions described in this disclosure. For example, the communication device may include a controller or sensor that generates control signals or data signals used by the communication equipment performing the communication functions of the communication device.

[0254] In addition, the communication device includes infrastructure equipment that communicates with or controls the above-mentioned non-limiting various devices, such as base stations, access points, and all other devices, equipment, and systems.

[0255] A terminal according to one embodiment of the present disclosure includes: a control circuit configured to set a first upper limit value of a frequency interval for configuring a first reference signal in a first bandwidth to be smaller than a second upper limit value of a frequency interval for configuring a second reference signal in a second bandwidth, where the second bandwidth is wider than the first bandwidth; and a transmitting circuit configured to transmit the first reference signal based on the first upper limit value.

[0256] In one embodiment of the present disclosure, the control circuit controls the frequency hopping of the first reference signal in units of configuring a transmission frequency band of the second reference signal in each unit time interval.

[0257] In one embodiment of the present disclosure, the control circuit controls frequency hopping of the first reference signal between a plurality of symbols configuring a plurality of the first reference signals within the unit time interval.

[0258] In one embodiment of the present disclosure, the control circuit controls the frequency hopping of the first reference signal according to a frequency hopping period of the second reference signal.

[0259] In one embodiment of the present disclosure, the first bandwidth is less than a threshold, the second bandwidth is greater than the threshold, and the threshold is 4 resource blocks.

[0260] In one embodiment of the present disclosure, when the first bandwidth is 2 resource blocks, the first upper limit value is less than 4 subcarriers.

[0261] In one embodiment of the present disclosure, when the first bandwidth is 1 resource block, the first upper limit value is less than 2 subcarriers.

[0262] A base station in one embodiment of the present disclosure includes: a control circuit that sets a first upper limit value of a frequency interval for configuring a first reference signal in a first bandwidth to be smaller than a second upper limit value of a frequency interval for configuring a second reference signal in a second bandwidth, where the second bandwidth is wider than the first bandwidth; and a receiving circuit that receives the first reference signal based on the first upper limit value.

[0263] In a communication method of one embodiment of the present disclosure, a terminal sets a first upper limit value of a frequency interval for configuring a first reference signal in a first bandwidth to be smaller than a second upper limit value of a frequency interval for configuring a second reference signal in a second bandwidth, and sends the first reference signal based on the first upper limit value, where the second bandwidth is wider than the first bandwidth.

[0264] In a communication method of one embodiment of the present disclosure, a base station sets a first upper limit value of a frequency interval for configuring a first reference signal in a first bandwidth to be smaller than a second upper limit value of a frequency interval for configuring a second reference signal in a second bandwidth, and receives the first reference signal based on the first upper limit value, wherein the second bandwidth is wider than the first bandwidth.

[0265] The disclosure of Japanese Patent Application No. 2020-121431 filed on July 15, 2020, including the specification, drawings, and abstract, is incorporated herein by reference in its entirety.

[0266] Industrial Applicability

[0267] One embodiment of the present disclosure is useful for a wireless communication system.

[0268] Description of Reference Numerals

[0269] 100 base stations

[0270] 101, 203 Control Department

[0271] 102 Coding / Modulation Unit

[0272] 103, 205 Sending Processing Unit

[0273] 104, 206 Sending Department

[0274] 105, 201 Receiving Department

[0275] 106, 202 receiving and processing unit

[0276] 107 Reference signal receiving unit

[0277] 200 Terminal

[0278] 204 is a reference signal generating unit.

Claims

1. A terminal, characterized in that: include: A control circuit determines a sequence length of a reference signal based on the number of sent combs; as well as a transmitter, transmitting the reference signal, The bandwidth of the reference signal is selected from a plurality of bandwidths including a first bandwidth and a second bandwidth, A first lower limit value of the sequence length in the first bandwidth is the same as a second lower limit value of the sequence length in the second bandwidth, A first upper limit value of the number of sent combs in the first bandwidth is smaller than a second upper limit value of the number of sent combs in the second bandwidth.

2. The terminal according to claim 1, wherein: The first bandwidth is smaller than the second bandwidth.

3. The terminal according to claim 1, wherein: The larger the number of sent combs is, the smaller the sequence length is. The terminal according to claim 1 , wherein: The first bandwidth is less than 4 resource blocks, and the second bandwidth is greater than or equal to 4 resource blocks. The terminal according to claim 1 , wherein: When the first bandwidth is 2 resource blocks and the second bandwidth is 4 resource blocks, the first upper limit value is 4 and the second upper limit value is 8. The terminal according to claim 1 , wherein: sending the reference signal based on a first frequency hopping for the first bandwidth or a second frequency hopping for the second bandwidth, A period of the first frequency hopping is longer than a period of the second frequency hopping.

7. The terminal according to claim 1, wherein: sending the reference signal based on a first frequency hopping for the first bandwidth or a second frequency hopping for the second bandwidth, The first frequency hop is composed of the second frequency hop and an additional frequency hop associated with a starting position on the second bandwidth.

8. The terminal according to claim 1, wherein: sending the reference signal based on a first frequency hopping for the first bandwidth or a second frequency hopping for the second bandwidth, In a period of the second frequency hopping, an amount of each frequency hopping in the first frequency hopping is the same as an amount of each frequency hopping in the second frequency hopping.

9. A communication method, characterized in that: The following steps are involved: Determine the sequence length of the reference signal based on the number of transmitted combs; and sending the reference signal, The bandwidth of the reference signal is selected from a plurality of bandwidths including a first bandwidth and a second bandwidth, A first lower limit value of the sequence length in the first bandwidth is the same as a second lower limit value of the sequence length in the second bandwidth, A first upper limit value of the number of sent combs in the first bandwidth is smaller than a second upper limit value of the number of sent combs in the second bandwidth.

10. A base station, characterized in that: include: The transmitter sends control information indicating the number of combs to be sent; as well as The receiver receives a reference signal using a sequence length determined based on the number of transmitted combs. The bandwidth of the reference signal is selected from a plurality of bandwidths including a first bandwidth and a second bandwidth, A first lower limit value of the sequence length in the first bandwidth is the same as a second lower limit value of the sequence length in the second bandwidth, A first upper limit value of the number of sent combs in the first bandwidth is smaller than a second upper limit value of the number of sent combs in the second bandwidth.

11. The base station according to claim 10, wherein: The first bandwidth is smaller than the second bandwidth.

12. The base station according to claim 10, wherein: The larger the number of sent combs is, the smaller the sequence length is.

13. The base station according to claim 10, wherein: The first bandwidth is less than 4 resource blocks, and the second bandwidth is greater than or equal to 4 resource blocks.

14. The base station according to claim 10, wherein: When the first bandwidth is 2 resource blocks and the second bandwidth is 4 resource blocks, the first upper limit value is 4 and the second upper limit value is 8.

15. The base station according to claim 10, wherein: sending the reference signal based on a first frequency hopping for the first bandwidth or a second frequency hopping for the second bandwidth, A period of the first frequency hopping is longer than a period of the second frequency hopping.

16. The base station according to claim 10, wherein: sending the reference signal based on a first frequency hopping for the first bandwidth or a second frequency hopping for the second bandwidth, The first frequency hop is composed of the second frequency hop and an additional frequency hop associated with a starting position on the second bandwidth.

17. The base station according to claim 10, wherein: sending the reference signal based on a first frequency hopping for the first bandwidth or a second frequency hopping for the second bandwidth, In a period of the second frequency hopping, an amount of each frequency hopping in the first frequency hopping is the same as an amount of each frequency hopping in the second frequency hopping.

18. A communication method, characterized in that: The following steps are involved: Sending control information indicating the number of Combs to be sent; and A reference signal is received using a sequence length determined based on the number of transmitted combs. The bandwidth of the reference signal is selected from a plurality of bandwidths including a first bandwidth and a second bandwidth, A first lower limit value of the sequence length in the first bandwidth is the same as a second lower limit value of the sequence length in the second bandwidth, A first upper limit value of the number of sent combs in the first bandwidth is smaller than a second upper limit value of the number of sent combs in the second bandwidth.

19. An integrated circuit, characterized in that: include: A control circuit controls a decision of a sequence length of a reference signal based on a number of transmitted combs; as well as a sending circuit, which controls the sending of the reference signal, The bandwidth of the reference signal is selected from a plurality of bandwidths including a first bandwidth and a second bandwidth, A first lower limit value of the sequence length in the first bandwidth is the same as a second lower limit value of the sequence length in the second bandwidth, A first upper limit value of the number of sent combs in the first bandwidth is smaller than a second upper limit value of the number of sent combs in the second bandwidth.

20. An integrated circuit, characterized in that: include: A sending circuit controls the sending of control information indicating the number of Combs to be sent; as well as A receiving circuit controls reception of a reference signal, wherein the reference signal is received using a sequence length determined based on the number of transmitted combs. The bandwidth of the reference signal is selected from a plurality of bandwidths including a first bandwidth and a second bandwidth, A first lower limit value of the sequence length in the first bandwidth is the same as a second lower limit value of the sequence length in the second bandwidth, A first upper limit value of the number of sent combs in the first bandwidth is smaller than a second upper limit value of the number of sent combs in the second bandwidth.

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