Terminal, base station, and communication method

Abstract

This terminal includes a receiving circuit for receiving a synchronization signal, and a control circuit for determining a correspondence relationship between a synchronization signal block transmission position and a synchronization signal block index, wherein the control circuit changes the correspondence relationship between the synchronization signal block transmission position and the synchronization signal block at a first reception timing of the synchronization signal block and a second reception timing thereof.

Description

[Technical Field]

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

[0002] The Third Generation Partnership Project (3GPP) supports the use of unlicensed bands to expand frequency bands. 3GPP is also studying SSB operation in unlicensed bands in the 52.6 GHz-71 GHz band. Note that SSB stands for SS / PBCH Block, SS stands for Synchronization Signal, and PBCH stands for Physical Broadcast Channel. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] R1-2102238, 3GPP TSG-RAN WG1 Meeting#104e [Non-patent document 2] R1-2007926, 3GPP TSG-RAN WG1 Meeting#103e [Non-patent document 3] 3GPP TS 38.213 V16.3.0 (2020-09) Summary of the Invention

[0004] In unlicensed bands, for example, a base station performs a Listen Before Talk (LBT) procedure before transmitting a signal. In the LBT procedure, the base station checks whether the signal transmission band is being used by other wireless stations before transmitting the signal.

[0005] However, in the current study, there are cases where the terminal is unable to receive the SSB index due to an LBT failure.

[0006] Non-limiting examples of the present disclosure contribute to providing a terminal, a base station, and a communication method that can receive an index of a synchronization signal block even if an LBT failure occurs.

[0007] A terminal according to one embodiment of the present disclosure has a receiving circuit that receives a synchronization signal, and a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block, and the control circuit changes the correspondence between a first reception timing and a second reception timing of the synchronization signal block.

[0008] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0009] According to one embodiment of the present disclosure, even if an LBT failure occurs, the terminal can receive the index of the synchronization signal block.

[0010] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief explanation of the drawings]

[0011] [Figure 1] A diagram showing an example of an SSB transmission interval and transmission period. [Figure 2] An example of cyclic transmission of SSB index [Figure 3] An example of when SSB index cannot be transmitted cyclically [Figure 4] Figure showing an example of cyclic transmission when the number of SSB indexes to be transmitted is reduced [Figure 5] FIG. 10 is a diagram showing an example in which the relationship between the SSB transmission position and the SSB index is changed between SS burst sets according to the first embodiment. [Figure 6] Block diagram showing an example of the configuration of a base station [Figure 7] Block diagram showing another example of the configuration of a base station [Figure 8] Block diagram showing an example of a terminal configuration [Figure 9] A diagram showing an example of operations from cell search to random access procedures between a base station and a terminal. [Figure 10] FIG. 10 is a block diagram showing a configuration example of a base station according to a second embodiment; [Figure 11] FIG. 10 is a block diagram showing a configuration example of a terminal according to a second embodiment; [Figure 12] A diagram showing an example of operations from cell search to random access procedures between a base station and a terminal. [Figure 13] FIG. 10 is a diagram showing an example of operation up to signal quality measurement by SSB between a base station and a terminal and reporting of measurement information according to the third embodiment. [Figure 14] Diagram of an example architecture of a 3GPP NR system [Figure 15] Schematic diagram showing functional separation between NG-RAN and 5GC [Figure 16] Sequence diagram of RRC connection setup / reconfiguration procedure [Figure 17] Schematic diagram showing usage scenarios for enhanced Mobile BroadBand (eMBB), massive Machine Type Communications (mMTC), and Ultra Reliable and Low Latency Communications (URLLC). [Figure 18] Block diagram illustrating an exemplary 5G system architecture for a non-roaming scenario DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or redundant explanation of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0013] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0014] (First embodiment) In the 5G standardization effort, 3GPP is currently discussing a new radio access technology (NR: New Radio), which is not necessarily backward compatible with LTE / LTE-Advanced. NR Release 17 considers operation in the 52.6GHz-71GHz band as a new frequency band. In the 52.6GHz-71GHz band, SSB transmission methods by base stations are being considered to enable initial connection and quality measurement in NR Standalone, which allows NR operation alone. LTE stands for Long Term Evolution.

[0015] The SSB consists of a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), a PBCH, and a PBCH-DMRS (De-Modulate Reference Signal). The PSS / SSS are synchronization signals that terminals use to synchronize with the carrier frequency.

[0016] The PCID (Physical Cell ID) of the cell is decoded from the PSS / SSS. The PBCH and PBCH-DMRS are allocated to the symbols before and after the PSS / SSS. The PBCH contains some of the broadcast information, and the terminal can obtain information such as the SFN (System Frame Number) indicating the number of the 10-ms time frame in which the SSB is transmitted, the half frame bit that determines whether the 5-ms time frame is the first or second half, the downlink control signal for initial connection, and the allocated resources for the downlink data signal.

[0017] Figure 1 shows an example of an SSB transmission interval and transmission cycle. In Release 16 NR, for example, as shown in Figure 1, SSBs are transmitted individually or as a set of multiple SSBs within a transmission interval called an SS burst set. SS burst sets are transmitted at intervals of {5 / 10 / 20 / 40 / 80 / 160} ms. SS burst sets are set as transmission intervals within 5 ms from the beginning of a 10 ms time frame or the beginning of a time frame plus a half frame (5 ms).

[0018] Each SSB in an SS burst set is transmitted as a signal with a different SSB index. The SSB index indicates the SSB transmission position within the SS burst set, and the terminal identifies the start of the time frame by decoding the SSB index.

[0019] The maximum number of SSB indexes in an SS burst set is determined for each band. In Release 17 NR, as in Release 16, it was agreed that the maximum number of SSB indexes for bands above 6 GHz is 64. SSB indexes are uniquely associated with PBCH and PBCH-DMRS sequences and reported to the terminal.

[0020] In high frequency bands, it is considered that base stations will apply transmit beamforming to ensure the communication distance and coverage area between the base station and terminal. NR therefore introduces a beam management function using SSB. Different SSB indexes within an SS burst set are transmitted using different downlink transmit beams, enabling beam-sweeping, which sequentially switches the beam direction for transmission. Note that the beam may also be an analog beam.

[0021] The terminal measures the downlink reception quality for each SSB in the SS burst set and determines the optimal downlink transmission beam. When the base station applies downlink transmission beamforming to an SSB, it applies an equivalent uplink reception beam to receive random access from the terminal that received that SSB. Therefore, the terminal transmits a PRACH (Physical Random Access Channel) using an RO (Rach Occasion), which is a resource associated with the detected SSB. By performing random access using the RO associated with the SSB index, the terminal can form the optimal downlink transmission and reception beam between the base station and the terminal.

[0022] NR-U, which is NR operation in unlicensed bands specified in Release 16, introduces the Discovery Burst Transmission Window (DBTW) as a method for transmitting SS burst sets. In unlicensed bands, the Listen Before Talk (LBT) procedure is performed before transmission.

[0023] In the LBT procedure, a signal is transmitted after checking whether the signal transmission band is not being used by another radio station (channel busy). Since signal transmission is not possible if an LBT failure occurs, the timing to start transmission of an SS burst set in NR-U does not necessarily start from the beginning of the time frame or the beginning of the time frame plus a half frame (5 ms). Therefore, it is possible that the SSB cannot be transmitted at the first SSB transmission position within the SS burst set. Therefore, DBTW allows cyclic transmission of the SSB index at different SSB transmission positions within the transmission interval. Note that an LBT failure may also be referred to as a channel busy or an LBT busy.

[0024] Figure 2 shows an example of cyclic transmission of SSB indexes. The terminal is notified of the SSB transmission position. The terminal calculates the SSB index using a predetermined formula from the decoded SSB transmission position. Because the SSB index is associated with a downlink transmission beam, the terminal can measure the downlink reception quality assuming that the propagation characteristics are the same even for different SSB transmission positions. Therefore, the base station can use DBTW to avoid the inability to transmit specific SSBs even when an LBT failure occurs.

[0025] In the 52.6 GHz to 71 GHz band, operation in unlicensed bands is also anticipated, and the introduction of DBTW is being considered (see, for example, Non-Patent Document 1).

[0026] In the 52.6 GHz-71 GHz band, the maximum number of SSB indexes supported in unlicensed bands is greater than the maximum number of SSB indexes supported conventionally (in the FR1 band). Therefore, when DBTW is operated in unlicensed bands, the number of SSB indexes to be transmitted and the number of SSB transmission positions that can be notified will be approximately the same. In this case, there will be SSB indexes that cannot be transmitted due to LBT failure, which will cause a problem of performance degradation for certain terminals. Note that FR1 stands for Frequency Range 1.

[0027] In NR-U specified in Release 16, the maximum number of SSB indexes and the number of SSB transmission positions that can be notified to a terminal are based on the subcarrier spacing (SCS: Sub-Carrier Space).

[0028] For example, when the SCS is 15 kHz, the maximum number of SSB indices is 4, and the number of SSB transmission positions that can be notified to the terminal is 10. Also, when the SCS is 30 kHz, the maximum number of SSB indices is 8, and the number of SSB transmission positions that can be notified to the terminal is 20. Therefore, when an LBT failure occurs within a DBTW, the number of cycle transmissions that can be performed at different SSB transmission positions is 2 or more for any SSB index.

[0029] On the other hand, in the 52.6 GHz-71 GHz band, it has been agreed that the maximum number of SSB indexes should be 64 in order to obtain a larger beamforming gain. Also, assuming that the number of notifiable SSB transmission positions is 64, as specified in FR2 (6 GHz-52.6 GHz band) in Release 15, cyclic transmission of SSB indexes at different SSB transmission positions by DBTW is not possible.

[0030] Figure 3 shows an example of a case where the SSB index cannot be cyclically transmitted. As shown in Figure 3, when an LBT failure occurs, the SSB index associated with the first SSB transmission position of the DBTW cannot be transmitted, and the performance of the terminal for which the transmission beam corresponding to that SSB index is optimal is degraded.

[0031] Note that Figure 3 shows an example assuming an SCS of 120 kHz, 64 SSB transmission positions, and two SSB transmission positions per slot. The interval including all SSB transmission positions is shorter than the 5 ms DBTW.

[0032] In order to address this issue, a measure has been proposed to reduce the number of SSB indexes to be transmitted and to achieve cyclic transmission (for example, Non-Patent Document 2).

[0033] 4 shows an example of cyclic transmission when the number of SSB indexes to be transmitted is reduced. Non-Patent Document 2 assumes, for example, that SSB index {0,...,47} is transmitted at SSB transmission position {0,...,47} and SSB index {0,...,15} is cyclically transmitted at SSB transmission position {48,...,63}. However, even in this case, if LBT failures occur up to SSB transmission position {0,...,19}, SSB index {16,...,19} cannot be transmitted.

[0034] As mentioned above, SSB indexes that become untransmittable due to an LBT failure tend to be biased toward SSB indexes associated with the beginning or first half of the SSB transmission position. Therefore, the performance degradation caused by an LBT failure is biased toward specific terminals for which a transmission beam corresponding to a specific SSB index is optimal. This results in a significant degradation in the performance of specific terminals.

[0035] Therefore, in the first embodiment, the relationship between the SSB transmission position and the SSB index is changed between the base station and the terminal, thereby preventing the impact of performance degradation due to an LBT failure from being concentrated on a specific terminal.

[0036] 5 is a diagram showing an example in which the relationship between the SSB transmission position and the SSB index is changed between SS burst sets according to the first embodiment. As shown in FIG. 5, changing the relationship between the SSB transmission position and the SSB index between SS burst sets prevents a bias in the SSB index that the base station cannot transmit due to an LBT failure.

[0037] For example, in the example in Figure 5, in a certain SS burst set, SSB index {#0, ..., #19} associated with SSB transmission position {#0, ..., #19} becomes untransmittable due to an LBT failure. However, in a different SS burst set, by associating SSB index {#0, ..., #19} with the latter SSB transmission position {#32, ..., #51}, SSB index {#0, ..., #19} becomes transmittable even if an LBT failure occurs at SSB transmission position {#0, ..., #19} in the same section.

[0038] However, the correspondence between the SSB transmission position and the SSB index must be recognized in agreement between the base station and the terminal. If the recognition of the correspondence does not match, the optimal downlink transmitting and receiving beams cannot be formed between the base station and the terminal.

[0039] Below, we will explain how the relationship between the SSB transmission position and the SSB index is changed between the base station and the terminal, and how the terminal performs initial connection using the SSB and performs quality measurement. We will also explain how the base station and the terminal determine the relationship between the SSB transmission position and the SSB index based on a signal periodically transmitted by the base station. Note that "determining" can also be referred to as "calculating."

[0040] 6 is a block diagram showing an example of the configuration of base station 10. Control unit 11 performs tasks such as setting the cycle of SS burst sets and updating the SFN. Control unit 11 also performs tasks such as scheduling control signals and data signals for initial connection.

[0041] In accordance with the SSB transmission timing, the control unit 11 outputs the SSB transmission position within the SS burst set to the SSB generation unit 13 and the SSB index determination unit 12. The control unit 11 outputs information to the SSB index determination unit 12 for determining the relationship between the SSB transmission position and the SSB index.

[0042] Information for determining the relationship between the SSB transmission position and the SSB index includes, for example, the SFN, half frame bit, and PCID. Hereinafter, information for determining the relationship between the SSB transmission position and the SSB index will be referred to as information on the relationship between the SSB transmission position and the SSB index.

[0043] The SSB index determination unit 12 determines the SSB index based on the SSB transmission position and the relationship information between the transmission position and the SSB index, and outputs the determined SSB index to the transmission beam control unit 15. The method of change in the SSB index determination unit 12 will be described in detail later.

[0044] The SSB generation unit 13 generates signal sequences for the PSS / SSS, PBCH, and PBCH-DMRS based on the input SSB transmission positions and outputs them to the transmission processing unit 14. The PSS / SSS is generated using a correlation sequence based on the PCID of the base station 10. The PBCH-DMRS is generated using a DMRS sequence based on the SSB transmission positions. The PBCH is generated by encoding and modulating PBCH information including the SSB transmission positions. The PBCH information includes information such as the SSB transmission positions, SFN, half frame bit, control signals for initial connection, and allocated resources for data signals. Note that in the present disclosure, the allocated resources for the control signals and data signals for initial connection may be determined based on either the SSB transmission positions or the SSB index.

[0045] The transmission processing unit 14 maps the SSB signal sequence input from the SSB generation unit 13 to the respective resources, performs processing such as OFDM modulation, and generates a transmission signal. The transmission processing unit 14 also checks the usage status of the transmission signal band from the LBT determination unit 18, and outputs the transmission signal to the transmission RF unit 16 when the LBT is completed.

[0046] The transmission beam control unit 15 outputs the downlink transmission beam direction corresponding to the SSB index input from the SSB index determination unit 12 to the transmission RF unit 16 .

[0047] The transmission RF unit 16 generates a radio signal by performing processes such as D / A conversion, up-conversion, and amplification on the transmission signal input from the transmission processing unit 14, and outputs the signal to the antenna 17. The transmission RF unit 16 also adjusts the phase and amplitude of the antenna elements of the antenna 17 so that the signal is directed in the beam direction output from the transmission beam control unit 15.

[0048] The antenna 17 forms a transmission beam controlled by the transmission RF unit 16 based on the radio signal input from the transmission RF unit 16 and radiates the beam to the terminal. The antenna 17 also forms a reception beam to receive radio signals from the terminal or other radio stations at a timing controlled by the reception RF unit 20. The antenna 17 outputs the received radio signal to the reception RF unit 20.

[0049] The LBT determination unit 18 performs LBT by monitoring the wireless usage status of the frequency band used from the received wave input by the RF reception unit 20. When the base station 10 starts signal transmission, the LBT determination unit 18 outputs the LBT result to the transmission processing unit 14.

[0050] The receiving beam control unit 19 outputs to the receiving RF unit 20 the uplink receiving beam direction in the RO corresponding to the SSB transmission position.

[0051] The receiving RF unit 20 performs receiving processes such as A / D conversion, down-conversion, and amplification on the radio signal input from the antenna 17, and outputs the signal to the receiving processing unit 21. At this time, the phase and amplitude of the antenna elements of the antenna 17 are adjusted so that the signal is directed in the direction of the beam output by the receiving beam control unit 19.

[0052] The reception processing unit 21 decodes the PRACH from the received signal input from the reception RF unit 20, and identifies the RO selected by the terminal.

[0053] Figure 7 is a block diagram showing another example configuration of base station 10. In Figure 7, the same components as in Figure 6 are assigned the same reference numerals. In Figure 7, the SSB transmission position of control unit 11 is output to reception beam control unit 19.

[0054] In the base station 10 of Fig. 6, RO is associated with the SSB transmission position. In the base station 10 shown in Fig. 7, RO is associated with the SSB index. When the reception beam of the base station 10 for RO is associated with the SSB transmission position as in Fig. 6, the timing of the beam direction is fixed, and reception beam control is simplified. When the reception beam of the base station 10 for RO is associated with the SSB index as in Fig. 7, the timing of the beam direction is randomized, making it possible to avoid periodic interference from other wireless stations.

[0055] The periods of the RO and the SS burst set do not necessarily have to match. Therefore, the SSB transmission position or SSB index referenced by the RO may refer to the relationship in a predetermined (e.g., immediately preceding) SS burst set. Alternatively, the SSB transmission position or SSB index referenced by the RO may be calculated separately by the RO.

[0056] 8 is a block diagram showing an example configuration of terminal 50. RF unit 51 performs reception processing such as down-conversion and A / D conversion on a radio signal received from base station 10 or another radio station via an antenna, and outputs the received signal to reception processing unit 52 and LBT determination unit 57. RF unit 51 also performs transmission processing such as D / A conversion, up-conversion, and amplification on a transmission signal input from transmission processing unit 58, and transmits the obtained radio signal from the antenna to base station 10.

[0057] The reception processing unit 52 detects the PSS / SSS of the received signal input from the RF unit 51 by performing correlation processing or the like, identifies the SSB resource, and outputs it to the SSB decoding unit 53.

[0058] The SSB decoding unit 53 detects the PCID from the PSS / SSS. The SSB decoding unit 53 detects the sequence number from the PBCH-DMRS. The SSB decoding unit 53 demodulates and decodes the PBCH information from the PBCH. The SSB decoding unit 53 identifies the SSB transmission position from the PBCH-DMRS sequence number and the PBCH information. The SSB decoding unit 53 also obtains relationship information between the SSB transmission position and the SSB index from the PBCH information. The SSB decoding unit 53 outputs the SSB transmission position and the relationship information between the SSB transmission position and the SSB index to the SSB index determination unit 54. The SSB decoding unit 53 measures the received signal quality of the SSB and outputs the result to the SSB selection unit 55.

[0059] The SSB index determination unit 54 determines an SSB index based on the SSB transmission position input from the SSB decoding unit 53 and information on the relationship between the SSB transmission position and the SSB index, and outputs the determined SSB index to the SSB selection unit 55. The method for changing the SSB index will be described in detail later, but the operation is similar to that of the SSB index determination unit 12 included in the base station 10.

[0060] The SSB selector 55 associates the received signal quality measured from the SSB with the SSB index, and determines the SSB index with the best received quality within the SS burst set. The SSB selector 55 outputs the determined SSB index to the preamble resource determiner 56.

[0061] The preamble resource determination unit 56 selects the RO associated with the input SSB index and outputs it to the transmission processing unit 58.

[0062] Furthermore, the recognition of the transmission and reception timing of the RO is made consistent between the base station 10 and the terminal 50. Therefore, whether the RO is associated with the reception timing of the SSB transmission position or the reception timing of the SSB index may be notified to the terminal 50 from the notification information. Alternatively, whether the RO is associated with the reception timing of the SSB transmission position or the reception timing of the SSB index may be known in the base station 10 and the terminal 50 from the common information described in the specification.

[0063] The LBT determination unit 57 performs LBT by monitoring the radio utilization status of the utilization frequency band based on the received wave input by the RF unit 51. When the signal transmission is started from the terminal 50, the LBT determination unit 57 outputs the LBT result to the transmission processing unit 58.

[0064] The transmission processing unit 58 generates a PRACH transmission signal using the RO input from the Preamble resource determination unit 56. The generated PRACH transmission signal is output to the RF unit 51. Also, the transmission processing unit 58 checks the usage status of the transmission signal band from the LBT determination unit 57, and outputs the transmission signal to the RF unit 51 when the LBT is completed.

[0065] <Initial connection operations of the base station and the terminal when the SSB transmission position and the SSB index are different> The initial connection operations of the base station and the terminal when the SSB transmission position and the SSB index are different are described. In the initial connection, the terminal acquires the time frame and resources for the initial connection even when there is no relationship information between the SSB transmission position and the SSB index.

[0066] FIG. 9 is a diagram showing an operation example from cell search to random access procedure between the base station and the terminal. The base station determines the notification information based on the SSB transmission position (S1). The base station calculates the SSB index at the SSB transmission position (S2). The base station performs LBT (S3). The base station radiates the beam associated with the SSB index at each SSB transmission position (S4). The base station transmits the synchronization signal and the notification signal to the terminal (S5).

[0067] The terminal detects the SSB transmission position from the broadcast information transmitted in S5 (S6). The terminal calculates the SSB index from the broadcast information and the SSB transmission position (S7). The terminal calculates the SSB index from the SSB transmission position or the SSB The allocation resources for the control signal and the data signal are calculated from the index (S8).

[0068] The terminal refers to the allocated resources calculated in S8 and receives a control signal and a data signal (SIB1: System Information Block Type 1) from the base station (S9). The terminal determines the resources (e.g., RO) to be used in the random access procedure from the SSB measurement results (SSB transmission position or SSB index) (S10). The terminal starts the random access procedure using the resources determined in S10 (S11).

[0069] During initial connection, the terminal synchronizes with the PSS / SSS to identify the PBCH-DMRS and PBCH in a specific resource. At this time, the terminal can obtain the SSB transmission position from the SSB broadcast information, and therefore can identify the start point of the time frame.

[0070] After detecting the SSB, the terminal detects the data signal broadcast by SIB1 and the control signal notifying the resource of the data signal. SIB1 includes broadcast information used in the random access procedure. The data signal and control signal for SIB1 are common signals in the cell. The resource allocated to the common signal for SIB1 is calculated as an offset value from the resource of the SSB. In addition, to reduce the amount of information to be notified, the MIB (Master Information Block) of the SSB broadcast information describes parameters for calculating the resource allocated to SIB1. Conventionally, the SSB transmission position is input into the formula for calculating the resource allocated to SIB1.

[0071] In FIG. 9, the base station and the terminal can calculate the SSB index at the time of the processing of S2 and S7. Therefore, when the terminal detects the allocation resource of the common signal for SIB1 (for example, at the time of the processing of S10), both the SSB transmission position and the SSB index can be used. For this reason, the input value of the calculation formula for the allocation resource of the common signal for SIB1 in the terminal may be either the SSB transmission position or the SSB index. If the SSB transmission position is used as the input value as in the conventional case, the change in the specification will be less. If the SSB index is used as the input value, similar to the reception beam of the RO, in the transmission of SIB1, the timing of the direction of the transmission beam from the base station is randomized, and the terminal can avoid periodic interference from other radio stations.

[0072] <Operation of calculating the SSB index from the SSB transmission position> Next, the details of the process of calculating the SSB index from the SSB transmission position, which is performed in the SSB index determination unit of the base station and the terminal, will be described. In the following description, the operation on the terminal side will be described. The base station calculates in the same operation as the terminal.

[0073] The details of calculation processes 1 and 2 are shown below. The calculation formula used in the calculation process here is the system common information defined in the specification. By changing the relationship between the SSB transmission position and the SSB index in the base station, the bias of the SSB index that cannot be transmitted by the base station due to LBT failure is suppressed. Also, by specifying the method (determination method) of changing calculation processes 1 and 2 in the specification, the terminal can calculate the SSB index from the SSB transmission position without additional signaling from the base station side.

[0074] · Calculation process 1 The base station changes the relationship between the SSB transmission position and the SSB index based on signals (information) that change periodically, such as the SFN and half frame bit included in the PBCH notified to the terminal.

[0075] The terminal calculates the SSB index from the SSB transmission position based on periodically changed signals such as the SFN and half frame bit included in the PBCH notified by the base station.

[0076] The SFN is divided into information included in the PBCH additional bit, which has a short change period, and information notified from the MIB, which has a long change period, among the PBCH information, but it is not necessary to refer to all SFNs.If the information included in the PBCH additional bit is referred to, the first embodiment can be applied even to a method of using an SSB that does not include an MIB.

[0077] -Calculation example 1-1 The base station shifts the SSB index for the SSB transmission position by a fixed amount based on periodically changing signals (information) such as the SFN and half frame bit included in the PBCH notified to the terminal.

[0078] The terminal identifies (determines) the relationship between the SSB transmission position and the SSB index by shifting the SSB index by a fixed amount from the SSB transmission position based on periodically changing signals such as the SFN and half frame bit contained in the PBCH notified by the base station.

[0079] By using a fixed amount of shift, the transmit beam direction set by the base station's transmit beam controller only needs to add a fixed time offset to the relationship between the SSB transmission position and the SSB index. This means that the transmit beam controller does not need to have multiple transmit beam control patterns according to the relationship between the SSB transmission position and the SSB index, and can be easily implemented.

[0080] The SSB index is calculated using, for example, the following equation (1).

[0081]

number

[0082] Here, SSB pos is the SSB transmission position. L is the maximum number of SSB indexes to be transmitted. N is the fixed shift amount. Note that N may be a different value for multiple different Ls or multiple different SCSs.

[0083] -Relationship Example 1-1 The SSB index at the SSB transmission position based on calculation example 1-1 is shown below. Table 1 shows an example of the relationship between the SSB transmission position and the SSB index when L=64, N=11, the SS burst set period is 10 ms (1 radio frame), and half frame bit = 0.

[0084] [Table 1]

[0085] -Calculation example 1-2 The base station shifts the SSB index for the SSB transmission position by a predetermined variable amount based on periodically changing signals (information) such as the SFN and half frame bit included in the PBCH notified to the terminal.

[0086] The terminal determines the relationship between the SSB transmission position and the SSB index by shifting the SSB index by a predetermined variable amount from the SSB transmission position based on periodically changed signals such as the SFN and half frame bit included in the PBCH notified by the base station. The variable amount may be a periodically changing amount.

[0087] The SSB index is calculated using, for example, the following equation (2).

[0088]

number

[0089] Here, SSB posis the SSB transmission position. L is the maximum number of SSB indexes transmitted. M is a shift-related quantity. If M is a relatively prime value (e.g., {3, 5, 7}) to the "SS burst set periodic frame" (i.e., {0.5, 1, 2, 4, 8, 16}), then the relationship between the original SSB transmission position and SSB index is established for M "SS burst sets."

[0090] Furthermore, if M is a relatively prime value, even if the "periodic frame of the SS burst set" is different (for example, periodic frame {1, 2}), the SSB index is shifted to a different SSB transmission position between each "SS burst set." Note that M may have different values ​​for multiple Ls or multiple SCSs.

[0091] Even if the shift is made variable, it is possible to obtain the same effect as in Calculation Example 1-1. Furthermore, by using Equation (2), it is possible to obtain the relationship between the SSB transmission position and the SSB index, which differs between SS burst sets, regardless of the number of SSB indexes and the "periodic frame of the SS burst set."

[0092] For example, in calculation example 1-1, when L=64 and N=16, the relationship between the SSB transmission position and the SSB index does not change depending on the "periodic frame of the SS burst set" (for example, when the periodic frame is 2). On the other hand, in calculation example 1-2, since M is a prime number for the "periodic frame of the SS burst set," the relationship between the SSB transmission position and the SSB index always changes.

[0093] The SSB index may be calculated using the SFN without using the half frame bit.

[0094] -Relationship Example 1-2 The SSB index at the SSB transmission position based on calculation example 1-2 is shown below. Table 2 shows an example of the relationship between the SSB transmission position and SSB index when L = 64, M = 3, the SS burst set period is 10 ms (1 radio frame), and half frame bit = 0. When SFN = 3, the relationship between the SSB transmission position and SSB index is the same as when SFN = 0.

[0095] [Table 2]

[0096] -Calculation example 1-3 The base station reverses the order of the SSB indexes for the SSB transmission positions based on periodically changing signals (information) such as the SFN and half frame bit included in the PBCH notified to the terminal.

[0097] The terminal determines whether the SSB transmission positions and SSB indexes are in forward or reverse order based on periodically changed signals such as the SFN and half frame bit included in the PBCH notified by the base station.

[0098] By reversing the order and switching in this way, the first SSB index, which is more likely to become untransmittable due to LBT failure, is swapped to the latter when switching, thereby leveling out the probability that each SSB index will become untransmittable.

[0099] -Relationship Example 1-3 The SSB index at the SSB transmission position based on calculation example 1-3 is shown below.

[0100] [Table 3]

[0101] -Calculation example 1-4 The base station changes the relationship between the SSB index and the SSB transmission position based on periodically changing signals (information) such as the SFN and half frame bit included in the PBCH notified to the terminal, and a pseudo-random number formula or table described in the specifications, etc.

[0102] The terminal determines the relationship between the SSB transmission position and the SSB index based on periodically changing signals such as the SFN and half frame bit included in the PBCH notified by the base station, and a pseudo-random number formula or table described in the specifications, etc. By basing the relationship between the SSB transmission order and the SSB index on a pseudo-random number formula or table described in advance in the specifications, etc., the SSB index can be further randomized between "SS burst sets."

[0103] -Relationship Example 1-4 The SSB index at the SSB transmission position based on calculation examples 1-4 is shown below. The specifications include a pseudo-random number formula or table that changes the relationship between the SSB transmission position and the SSB index according to the SFN and SSB transmission position, as shown in Table 4, and the base station and terminal change the relationship between the SSB transmission position and the SSB index according to the SFN. In this case, the SSB index does not need to be ordered.

[0104] [Table 4]

[0105] -Calculation example 1-5 The calculation examples listed above may be combined, and by combining them, the effects of each calculation example can be obtained.

[0106] For example, by combining calculation example 1-2 and calculation example 1-3, the relationship between the SSB transmission position and the SSB index may be changed as shown in relationship example 1-5 below. In calculation example 1-3, depending on the "periodic frame of the SS burst set," the relationship between the SSB transmission position and the SSB index may not change between SS burst sets (for example, when SFN=0 and SFN=2). On the other hand, by combining them as in setting example 1-5 below, it is possible to change the relationship between the SSB transmission position and the SSB index between SS burst sets.

[0107] -Relationship Example 1-5 [Table 5]

[0108] Calculation process 2 The base station changes the relationship between the SSB transmission position and the SSB index based on periodically changing signals (information) such as the SFN and half frame bit included in the PBCH notified to the terminal, and the PCID of the base station itself.

[0109] The terminal assumes that the relationship between the SSB transmission position and the SSB index has changed based on periodically changing signals such as the SFN and half frame bit included in the PBCH notified by the base station, and broadcast information such as the PCID.

[0110] As shown in the following calculation example, by changing the relationship information taking into account the PCID, the combination of interfering beams between cells is changed over time, thereby randomizing the interference between cells.

[0111] -Calculation example 2-1 The base station shifts the SSB index for the SSB transmission position by a predetermined fixed amount based on periodically changing signals (information) such as the SFN and half frame bit included in the PBCH notified to the terminal and the PCID of the base station itself.

[0112] The terminal identifies (determines) the relationship between the SSB transmission position and the SSB index by shifting the SSB index by a fixed amount from the SSB transmission position based on periodically changing signals such as the SFN and half frame bit included in the PBCH notified by the base station, and broadcast information such as the PCID.

[0113] The SSB index is calculated, for example, using the following equation (3).

[0114]

number

[0115] Here, SSB pos is the SSB transmission position. L is the maximum number of SSB indexes to be transmitted. N is the fixed shift amount. K PCID is a fixed coefficient based on the PCID. Note that N may have different values ​​for multiple different Ls or multiple different SCSs.

[0116] In the above description, the fixed shift amount N in Calculation Example 1-1 is changed according to the PCID, but M described in Calculation Example 1-2 may be changed according to the PCID. In this way, it is possible to achieve the randomization of inter-cell interference while obtaining the effects of Calculation Example 1-1 or Calculation Example 1-2.

[0117] -Relationship Example 2-1 The SSB index at the SSB transmission position based on calculation example 2-1 is shown below. Table 6 shows an example of the relationship between the SSB transmission position and the SSB index when L=64, N=11, the SS burst set period is 10 ms (1 radio frame), and half frame bit = 0. Table 6 also shows the relationship between the SSB transmission position and the SSB index when L=64, N=11, the SS burst set period is 10 ms (1 radio frame), and half frame bit = 0. PCID =1(if PCID mod 2==0), and K PCID= 2 (if PCID mod 2 = 1), the relationship between the SSB transmission position and the SSB index can be changed for each PCID.

[0118] [Table 6]

[0119] -Calculation example 2-2 The base station switches the method of changing the SSB index relative to the SSB transmission position (the method of changing the relationship between the SSB transmission position and the SSB index) based on periodically changing signals (information) such as the SFN and half frame bit included in the PBCH notified to the terminal and the PCID of the base station itself.

[0120] The terminal changes the method for changing the relationship between the SSB transmission position and the SSB index based on periodically changed signals such as the SFN and half frame bit included in the PBCH notified by the base station, and broadcast information such as the PCID.

[0121] By changing the change method depending on the PCID in this way, it is possible to achieve randomization of inter-cell interference while obtaining the effects of calculation examples 1-1 to 1-5.

[0122] -Relationship Example 2-2 Table 7 shows an example of switching the change method depending on the PCID. In the example of Table 7, if (PCID mod 2==0), calculation example 1-2 is applied, and if (PCID mod 2==1), calculation example 1-3 is applied.

[0123] [Table 7]

[0124] As described above, the base station determines the correspondence between SSB transmission positions and SSB indexes based on the broadcast signal it transmits. The base station changes this correspondence between the first SS burst set and the second SS burst set in the broadcast signal. Furthermore, the terminal determines the correspondence between SSB transmission positions and SSB indexes based on the broadcast signal it receives. The terminal changes this correspondence between the first SS burst set and the second SS burst set in the broadcast signal.

[0125] In this way, the base station and terminal change the correspondence between SSB transmission positions and SSB indexes based on the broadcast signal, so the correspondence between SSB transmission positions and SSB indexes between the base station and terminal matches. Furthermore, even if an LBT failure occurs in the first SS burst set and the second SS burst set, the base station and terminal can receive different SSB indexes in the first SS burst set and the second SS burst set because the correspondence between SSB transmission positions and SSB indexes between the first SS burst set and the second SS burst set has been changed. This allows the terminal to receive all SSB indexes even if an LBT failure occurs.

[0126] (Second embodiment) In the second embodiment, the base station and the terminal calculate the relationship between the SSB transmission position and the SSB index based on the signal periodically transmitted by the base station and the signaling information of SIB1 to which information on the relationship between the SSB transmission position and the SSB index is added.

[0127] Fig. 10 is a block diagram showing an example of the configuration of a base station 10 according to the second embodiment. In Fig. 10, the same components as in Fig. 6 are denoted by the same reference numerals.

[0128] The control unit 11 outputs relationship information between the SSB transmission position and the SSB index to the SSB index determination unit 12 and the common signal generation unit 22. The control unit 11 also changes the relationship information between the SSB transmission position and the SSB index in accordance with control from the upper network. When the relationship between the SSB transmission position and the SSB index is changed, updated information is output to the common signal generation unit 22. Other operations are the same as those in the first embodiment.

[0129] The common signal generator 22 generates a data signal that broadcasts SIB1 for initial connection and a control signal that notifies the allocated resources of the data signal, and outputs them to the transmission processor 14. The signaling information included in SIB1 includes relationship information between the SSB transmission position and the SSB index input from the controller 11. If the relationship information between the SSB transmission position and the SSB index is changed, it is notified from the base station to the terminal via SIB1.

[0130] In Figure 10, the SSB transmission position is input to the receiving beam control unit 19, as in Figure 6, and RO is associated with the SSB transmission position, but as in Figure 7, the SSB index may be input to the receiving beam control unit 19, and RO may be associated with the SSB index.

[0131] Fig. 11 is a block diagram showing an example of the configuration of a terminal 50 according to the second embodiment. In Fig. 11, the same components as those in Fig. 8 are denoted by the same reference numerals.

[0132] The reception processing unit 52 identifies the SSB resource as in FIG. 8 and outputs it to the SSB decoding unit 53. Then, the reception processing unit 52 acquires the SSB transmission position from the SSB decoding unit 53. The reception processing unit 52 identifies the allocation resource for the control signal of the common signal from the SSB transmission position. The reception processing unit 52 acquires the data series of the common signal and outputs it to the common signal decoding unit 59.

[0133] The common signal decoding unit 59 decodes a control signal for notifying the allocated resources of the data signal for initial connection, and decodes SIB1 from the data signal. It obtains the relationship information between the SSB transmission position and the SSB index from the signaling information included in SIB1, and outputs it to the SSB index determination unit 54.

[0134] Based on the relationship information between the SSB transmission position and the SSB index input from the SSB decoding unit 53 and the common signal decoding unit 59, the SSB index determination unit 54 determines the SSB index from the SSB transmission position and outputs it to the SSB selection unit.

[0135] <Initial connection operations of the base station and the terminal when the SSB transmission position and the SSB index are different> FIG. 12 is a diagram showing an operation example from cell search to random access procedure between the base station and the terminal according to the second embodiment. In FIG. 12, the same processes as those in FIG. 9 are denoted by the same reference numerals. Hereinafter, the processing parts different from those in FIG. 9 will be described.

[0136] In the operation of FIG. 12, after detecting the SSB transmission position at S6, the terminal calculates the allocated resources of the control signal and the data signal from the SSB transmission position (S21). The terminal refers to the allocated resources calculated at S21 and receives the control signal and the data signal (SIB1) from the base station (S9). SIB1 includes information for changing the relationship between the SSB transmission position and the SSB index (for example, information for changing the shift amount).

[0137] The terminal calculates the SSB index based on the notification information, the SSB transmission position detected at S6, and the information included in SIB1 (S22). The terminal determines the resources (for example, RO) to be used in the random access procedure from the SSB measurement result (SSB transmission position or SSB index) (S23).

[0138] The difference between the process of FIG. 12 and the process of FIG. 8 is that the terminal cannot calculate the SSB index until it decodes SIB1. Therefore, the terminal calculates the allocation resource of the common signal for SIB1 from the SSB transmission position (S21).

[0139] Note that at the time of the random access procedure, the terminal has identified both the SSB transmission position and the SSB index. Therefore, the base station and the terminal may associate the RO with either the SSB transmission position or the SSB index. Also, the base station may switch which of the SSB transmission position and the SSB index the RO is associated with and notify the terminal by SIB1.

[0140] <Operation of calculating SSB index from SSB transmission position> Next, the details of the process of calculating the SSB index from the SSB transmission position, which is performed in the SSB index determination units of the base station and the terminal, will be described. In the following description, the operation on the terminal side will be described. The base station calculates in the same operation as the terminal.

[0141] The details of calculation process 3 are shown below. Here, the calculation formula used in the calculation process may be system common information defined in the specification or signaling information given from the base station.

[0142] ·Calculation process 3 The base station changes the relationship between the SSB transmission position and the SSB index based on the signal (information) that changes periodically such as the SFN and half frame bit included in the PBCH notified to the terminal and the signaling information given to SIB1.

[0143] The terminal calculates the SSB index from the SSB transmission position based on the signal that changes periodically such as the SFN and half frame bit included in the PBCH notified from the base station and the signaling information notified by SIB1 from the base station.

[0144] Since the relationship between the SSB transmission position and the SSB index can be changed by SIB1 signaling information from the base station, the base station can perform adaptive control, for example, by switching the change method depending on the interference situation in its own cell.

[0145] -Calculation example 3-1 The base station shifts the SSB index for the SSB transmission position by a predetermined amount based on periodically changing signals (information) such as the SFN and half frame bit included in the PBCH notified to the terminal, and the signaling information of SIB1.

[0146] The terminal determines the relationship between the SSB transmission position and the SSB index by shifting the SSB index by a predetermined amount from the SSB transmission position based on periodically changed signals such as the SFN and half frame bit contained in the PBCH notified by the base station, and SIB1 signaling information.

[0147] The SSB index is calculated using, for example, the following equation (4).

[0148]

number

[0149] Here, SSB pos is the SSB transmission position. L is the maximum number of SSB indexes to be transmitted. N sig is the shift amount for each cell notified by SIB1. sig may be different values ​​for multiple different L's and multiple different SCS's.

[0150] In the above explanation, the fixed shift amount N in calculation example 1-1 is N sig The M in Calculation Example 1-2 has been changed to M sig It may be changed as:

[0151] By changing the shift amount based on the SIB1 signaling information, the shift amount can be adjusted for each cell, and more flexible randomization of inter-cell interference can be achieved than in Calculation Example 1-1, Calculation Example 1-2, or Calculation Example 2-1.

[0152] -Calculation example 3-2 The base station switches the method of changing the SSB index for the SSB transmission position based on the SIB1 signaling information. The base station changes the SSB index for the SSB transmission position based on periodically changing signals (information) such as SFN and half frame bit included in the PBCH notified to the terminal, and broadcast information such as PCID.

[0153] The terminal changes the method of changing the SSB index relative to the SSB transmission position based on the SIB1 signaling information. The terminal identifies the SSB index from the SSB transmission position based on periodically changed signals such as SFN and half frame bit included in the PBCH notified by the base station, and broadcast information such as PCID.

[0154] The change method at this time may be any of the methods in Calculation Examples 1-1 to 1-5. Also, by including the PCID, the change method may be any of the methods in Calculation Examples 2-5 to 2-3.

[0155] In this way, by switching the change method based on SIB1 signaling information, it is possible to adaptively control the randomization of inter-cell interference while obtaining the effects of Calculation Examples 1-1 to 1-5 or Calculation Examples 2-1 to 2-3.

[0156] -Calculation example 3-3 The base station controls whether to apply a change to the SSB index change method for the SSB transmission position based on the on / off flag included in the SIB1 signaling information. The base station switches the method for changing the SSB index for the SSB transmission position based on periodically changing signals (information) such as SFN and half frame bit included in the PBCH notified to the terminal, and broadcast information such as PCID.

[0157] The terminal determines whether a change in the SSB index change method for the SSB transmission position is applied based on the on / off flag included in the SIB1 signaling information. If a change in the change method is applied, the terminal identifies the SSB index from the SSB transmission position based on periodically changed signals such as the SFN and half frame bit included in the PBCH notified by the base station, and broadcast information such as the PCID.

[0158] The change method at this time may be any of the methods in Calculation Examples 1-1 to 1-5 or Calculation Examples 2-1 to 2-3.

[0159] As with calculation processes 1 and 2, the change method is changed according to the SFN and half frame bit contained in the PBCH, and the PCID, etc., and by switching the SIB1 signaling information using an on / off flag, the amount of information to be included in the SIB1 signaling information only needs to be 1 bit, minimizing the amount of information to be added.

[0160] As described above, the terminal and base station change the shift amount of the correspondence relationship between the SSB transmission position and the SSB index based on the information included in SIB1. The terminal and base station also switch the method of changing the correspondence relationship between the SSB transmission position and the SSB index based on the information included in SIB1. This also allows the terminal to receive the SSB index even if an LBT failure occurs.

[0161] (Third embodiment) In the third embodiment, based on the signals transmitted by the base station aperiodically, the base station and the terminal calculate the relationship between the SSB transmission position and the SSB index.

[0162] <SSB measurement operations of the base station and the terminal when the SSB transmission position and the SSB index are different> FIG. 13 is a diagram showing an operation example from the signal quality measurement by SSB between the base station and the terminal according to the third embodiment to the reporting of the measurement information. The base station transmits a control signal or a data signal (S31). The control signal or the data signal is transmitted aperiodically (arbitrarily). Note that the control signal may be a PDCCH (Physical Downlink Control CHannel). The data signal may be a PDSCH (Physical Downlink Shared CHannel).

[0163] Based on the control signal or the data signal received in S31, the terminal recognizes (determines) the relationship between the SSB transmission position and the SSB index (S32).

[0164] The base station determines the notification information based on the SSB transmission position (S33). The base station calculates the SSB index at the SSB transmission position (S34). The base station performs LBT (S35). If the base station is not LBT busy, it radiates the beam associated with the SSB index at each SSB transmission position (S36) and transmits the synchronization signal and the notification signal (S37).

[0165] The terminal detects the SSB transmission position from the notification information of the notification signal received in S37 (S38). Using the SSB transmission position detected in S38, the terminal refers to the relationship between the SSB transmission position and the SSB index determined in S32 and calculates the SSB index (S39). The terminal measures the signal quality of the beam signal at the SSB index calculated in S39 and transmits the measured information to the base station (S40).

[0166] In Fig. 13, the relationship information between the SSB transmission position and the SSB index is changed based on the non-periodically transmitted signal, so the terminal cannot acquire the time frame and resources for the initial connection from the SSB without the relationship information. Therefore, the relationship information between the SSB transmission position and the SSB index is notified to the terminal in advance from the base station. That is, the third embodiment assumes the operation of the SSB in a non-initial connection state.

[0167] For example, in a secondary cell, an SSB for channel quality measurement may be transmitted using resources or a frequency band different from those of an SSB for synchronization during initial connection. Therefore, the processing according to the third embodiment may be restricted to be applied to the SSB for measurement but not to the SSB for initial connection.

[0168] 13, the base station and terminal recognize the relationship between the SSB transmission position and the SSB index before transmitting the SS burst set, and can therefore calculate the SSB index at the time of processing, for example, S32, S34, or S39.

[0169] Calculation process 4 The base station changes the relationship between the SSB transmission position and the SSB index based on signaling information included in the data signal sent to the terminal.

[0170] The terminal calculates the SSB index from the SSB transmission position based on the signaling information included in the data signal notified from the base station.

[0171] Since the relationship between the SSB transmission position and the SSB index can be changed by signaling information from the base station, similar to calculation process 3, the base station can perform adaptive control, for example, by switching the change method depending on the interference situation in its own cell.

[0172] Calculation process 5 The base station changes the relationship between the SSB transmission position and the SSB index based on, for example, DCI (Downlink Control Information) included in a control signal sent to the terminal.

[0173] The terminal calculates the SSB index from the SSB transmission position based on the DCI included in the control signal notified from the base station.

[0174] Since the relationship between the SSB transmission position and the SSB index can be changed by DCI from the base station, the base station can perform adaptive control, for example, by switching the change method depending on the interference situation in its own cell, as in calculation process 3. Furthermore, since the relationship information can be changed by DCI, dynamic switching is possible.

[0175] As described above, the base station and the terminal determine the relationship between the SSB transmission position and the SSB index based on the signal transmitted aperiodically by the base station. This also allows the terminal to receive the SSB index even if an LBT failure occurs.

[0176] The embodiments of the present disclosure have been described.

[0177] Although the above embodiments have been described using the 52.6 GHz-71 GHz band as an example, the present disclosure is not limited to this and may be used in bands lower than 52.6 GHz and higher than 71 GHz. The present disclosure can also achieve similar effects when the number of SSBs to be transmitted is large or when there are limitations on the number of SSBs that can be notified or the transmission duration of DBTW.

[0178] Although the above embodiments have been described using examples of application to unlicensed bands, the present disclosure is not limited to this and may also be used in licensed bands. When applied to licensed bands, it is possible to obtain effects such as randomizing inter-cell interference by randomizing the transmission beam direction of base stations and reducing the cost of wireless devices by standardizing the operation method between licensed and unlicensed bands.

[0179] The above embodiments may be limited to be applied when the total number of SSB indexes is equal to or greater than X. For example, when the number of SSB transmission positions that can be notified is 64, X may be set to 32. In other words, they may be applied when the number of SSB indexes exceeds half the number of SSB transmission positions, and there are SSBs that cannot be transmitted cyclically.

[0180] The application of each of the above embodiments may be switched based on capability information of the terminal. For example, when it is known that the base station operates in an optional band based on the capability information of the terminal, each of the above embodiments may be applied.

[0181] In the specifications (see, for example, Non-Patent Document 3), the term "SSB transmission position" in this disclosure may be read as "candidate SS / PBCH block index" or "SSB candidate position." The term "SSB index" may be read as "SS / PBCH block index" or "SSB candidate index."

[0182] In the above embodiments, examples have been described in which the relationship between the SSB transmission position and the SSB index is changed, but the correspondence between the RO resource number and the SSB index may also be changed in a similar manner. This provides the same effects as those shown in the embodiments regarding random access. For example, as shown in Table 8, the RO resource number and the corresponding SSB index are changed according to the SFN. This makes it possible to randomize uplink interference related to random access from a terminal.

[0183] [Table 8]

[0184] In the above, the terminal may be referred to as, for example, user equipment (UE) or a mobile station, and the base station may be referred to as, for example, a gNB.

[0185] The notation "··· part" in each of the above-mentioned embodiments may be replaced with other notations such as "··· circuitry," "··· device," "··· unit," or "··· module."

[0186] (supplement) Information indicating whether the terminal supports the functions, operations, or processes described in each of the above-mentioned embodiments may be transmitted (or notified) from the terminal to the base station, for example, as capability information or capability parameters of the terminal.

[0187] The capability information may include an information element (IE) that individually indicates whether the terminal supports at least one of the functions, operations, or processes described in each of the above-described embodiments, or may include an information element that indicates whether the terminal supports a combination of any two or more of the functions, operations, or processes described in each of the above-described embodiments.

[0188] For example, the base station may determine (or decide or assume) functions, operations, or processes that the terminal that transmitted the capability information supports (or does not support) based on the capability information received from the terminal. The base station may perform operations, processes, or controls according to the determination result based on the capability information. For example, the base station may control allocation (in other words, scheduling) of at least one of downlink resources such as PDCCH or PDSCH and uplink resources such as PUCCH or PUSCH based on the capability information received from the terminal.

[0189] Note that the fact that a terminal does not support some of the functions, operations, or processes described in the above-described embodiments may be interpreted as meaning that such some of the functions, operations, or processes are restricted in the terminal. For example, information or a request regarding such restrictions may be notified to the base station.

[0190] Information regarding the capabilities or limitations of the terminal may, for example, be defined in a standard, or may be implicitly notified to the base station in association with information known at the base station or information transmitted to the base station.

[0191] (control signal) In the present disclosure, a downlink control signal (or downlink control information) related to an embodiment of the present disclosure may be, for example, a signal (or information) transmitted in a Physical Downlink Control Channel (PDCCH) of a physical layer, or a signal (or information) transmitted in a Medium Access Control Control Element (MAC CE) or Radio Resource Control (RRC) of a higher layer. Furthermore, the signal (or information) is not limited to being notified by a downlink control signal, but may be predefined in a specification (or standard) or preconfigured in a base station and a terminal.

[0192] In the present disclosure, an uplink control signal (or uplink control information) related to an embodiment of the present disclosure may be, for example, a signal (or information) transmitted in a PUCCH of a physical layer, or a signal (or information) transmitted in a MAC CE or RRC of a higher layer. Furthermore, the signal (or information) is not limited to being notified by an uplink control signal, but may be predefined in a specification (or standard), or may be preconfigured in a base station and a terminal. Furthermore, the uplink control signal may be replaced with, for example, uplink control information (UCI), 1st stage sidelink control information (SCI), or 2nd stage SCI.

[0193] (base station) In an embodiment of the present disclosure, the base station may be a Transmission Reception Point (TRP), a cluster head, an access point, a Remote Radio Head (RRH), an eNodeB (eNB), a gNodeB (gNB), a Base Station (BS), a Base Transceiver Station (BTS), a parent device, a gateway, or the like. Furthermore, in sidelink communication, a terminal may play the role of a base station. Instead of a base station, a relay device that relays communication between an upper node and a terminal may be used. Alternatively, a roadside unit may be used.

[0194] (Uplink / Downlink / Sidelink) An embodiment of the present disclosure may be applied to, for example, any of an uplink, a downlink, and a sidelink. For example, an embodiment of the present disclosure may be applied to a Physical Uplink Shared Channel (PUSCH), a Physical Uplink Control Channel (PUCCH), or a Physical Random Access Channel (PRACH) in the uplink, a Physical Downlink Shared Channel (PDSCH), a PDCCH, or a Physical Broadcast Channel (PBCH) in the downlink, or a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Control Channel (PSCCH), or a Physical Sidelink Broadcast Channel (PSBCH) in the sidelink.

[0195] The PDCCH, PDSCH, PUSCH, and PUCCH are examples of a downlink control channel, a downlink data channel, an uplink data channel, and an uplink control channel, respectively. The PSCCH and PSSCH are examples of a sidelink control channel and a sidelink data channel. The PBCH and PSBCH are examples of a broadcast channel, and the PRACH is an example of a random access channel.

[0196] (Data channel / Control channel) An embodiment of the present disclosure may be applied to, for example, either a data channel or a control channel. For example, the channel in an embodiment of the present disclosure may be replaced with any of the data channels PDSCH, PUSCH, and PSSCH, or the control channels PDCCH, PUCCH, PBCH, PSCCH, and PSBCH.

[0197] (reference signal) In one embodiment of the present disclosure, the reference signal is a signal known to both the base station and the mobile station, and may be called a Reference Signal (RS) or a pilot signal. The reference signal may be a Demodulation Reference Signal (DMRS), a Channel State Information - Reference The reference signal may be any of a Cell Signal Indicator-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).

[0198] (time interval) In an embodiment of the present disclosure, the unit of time resource is not limited to one or a combination of slots and symbols, but may be, for example, a time resource unit such as a frame, a superframe, a subframe, a slot, a time slot subslot, a minislot, or a symbol, an Orthogonal Frequency Division Multiplexing (OFDM) symbol, or a Single Carrier-Frequency Division Multiplexing (SC-FDMA) symbol, or another time resource unit. Furthermore, the number of symbols included in one slot is not limited to the number of symbols exemplified in the above-mentioned embodiment, and may be another number of symbols.

[0199] (frequency band) An embodiment of the present disclosure may be applied to either a licensed band or an unlicensed band.

[0200] (communication) An embodiment of the present disclosure may be applied to any of communication between a base station and a terminal (Uu link communication), communication between terminals (Sidelink communication), and Vehicle to Everything (V2X) communication. For example, the channel in an embodiment of the present disclosure may be replaced with any of PSCCH, PSSCH, Physical Sidelink Feedback Channel (PSFCH), PSBCH, PDCCH, PUCCH, PDSCH, PUSCH, and PBCH.

[0201] An embodiment of the present disclosure may be applied to a terrestrial network, a non-terrestrial network (NTN) using a satellite or a high altitude pseudo satellite (HAPS), or a terrestrial network in which transmission delay is large compared to the symbol length or slot length, such as a network with a large cell size or an ultra-wideband transmission network.

[0202] (antenna port) In one embodiment of the present disclosure, an antenna port refers to a logical antenna (antenna group) consisting of one or more physical antennas. For example, an antenna port does not necessarily refer to a single physical antenna, but may refer to an array antenna consisting of multiple antennas. For example, the number of physical antennas that an antenna port is composed of is not specified, and the antenna port may be specified as the smallest unit by which a terminal station can transmit a reference signal. Furthermore, an antenna port may also be specified as the smallest unit for multiplying a weighting factor of a precoding vector.

[0203] <5G NR system architecture and protocol stack> 3GPP is working on the next release of fifth-generation cellular technology (also known as 5G), which includes 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 at the end of 2017, allowing for the prototyping and commercial deployment of 5G NR compliant devices (e.g., smartphones).

[0204] For example, the system architecture assumes a Next Generation - Radio Access Network (NG-RAN) with gNBs. The gNBs provide UE-side termination of NG radio access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocols. The gNBs are connected to each other via an Xn interface. The gNBs are also connected to a Next Generation Core (NGC) via a Next Generation (NG) interface, more specifically to an Access and Mobility Management Function (AMF) (e.g., a specific core entity that performs AMF) via an NG-C interface, and to a User Plane Function (UPF) (e.g., a specific core entity that performs UPF) via an NG-U interface. The NG-RAN architecture is shown in Figure 14 (see, for example, 3GPP TS 38.300 v15.6.0, section 4).

[0205] The NR user plane protocol stack (see, for example, 3GPP TS 38.300, section 4.4.1) includes the Packet Data Convergence Protocol (PDCP) sublayer (see, for example, TS 38.300, section 6.4), the Radio Link Control (RLC) sublayer (see, for example, TS 38.300, section 6.3), and the Medium Access Control (MAC) sublayer (see, for example, TS 38.300, section 6.2), which are terminated on the network side at the gNB. A new Access Stratum (AS) sublayer (Service Data Adaptation Protocol (SDAP)) has also been introduced on top of PDCP (see, for example, 3GPP TS 38.300, section 6.5). A control plane protocol stack has also been defined for NR (see, for example, TS 38.300, section 4.4.2). An overview of Layer 2 functions is given in Section 6 of TS 38.300. The functions of the PDCP sublayer, RLC sublayer, and MAC sublayer are listed in clauses 6.4, 6.3, and 6.2 of TS 38.300, respectively. The functions of the RRC layer are listed in clause 7 of TS 38.300.

[0206] For example, the Medium-Access-Control layer handles logical channel multiplexing and scheduling and scheduling-related functions, including handling various numerologies.

[0207] For example, the physical layer (PHY) is responsible for coding, PHY HARQ processing, modulation, multi-antenna processing, and mapping of signals to appropriate physical time-frequency resources. The physical layer also handles mapping of transport channels to physical channels. The physical layer provides services to the MAC layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used for transmitting a specific transport channel, and each transport channel is mapped to a corresponding physical channel. For example, physical channels include the Physical Random Access Channel (PRACH), the Physical Uplink Shared Channel (PUSCH), and the Physical Uplink Control Channel (PUCCH) as uplink physical channels, and the Physical Downlink Shared Channel (PDSCH), the Physical Downlink Control Channel (PDCCH), and the Physical Broadcast Channel (PBCH) as downlink physical channels.

[0208] NR use cases / deployment scenarios may include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), which have diverse requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps in the downlink and 10 Gbps in the uplink) and effective (user-experienced) data rates approximately three times higher than those offered by IMT-Advanced. Meanwhile, URLLC imposes stricter requirements for ultra-low latency (0.5 ms user-plane latency for both UL and DL) and high reliability (1-10-5 within 1 ms). Finally, mMTC may require preferably high connection density (1,000,000 devices / km2 in urban environments), wide coverage in adverse environments, and extremely long battery life (15 years) for low-cost devices.

[0209] Therefore, OFDM numerology (e.g., subcarrier spacing, OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) suitable for one use case may not be valid for another use case. For example, low-latency services may preferably require a shorter symbol length (and therefore a larger subcarrier spacing) and / or fewer symbols per scheduling interval (also referred to as TTI) than mMTC services. Furthermore, deployment scenarios with large channel delay spreads may preferably require a longer CP length than scenarios with small delay spreads. Subcarrier spacing may be optimized accordingly to maintain similar CP overhead. NR may support one or more subcarrier spacing values. Correspondingly, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, etc. are currently 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.

[0210] In the new radio system 5G-NR, a resource grid of subcarriers and OFDM symbols is defined for each numerology and each carrier in the uplink and downlink. Each element of the resource grid is called a resource element and is specified based on a frequency index in the frequency domain and a symbol position in the time domain (see 3GPP TS 38.211 v15.6.0).

[0211] <Functional separation between NG-RAN and 5GC in 5G NR> Figure 15 shows the functional separation between NG-RAN and 5GC. The logical node of NG-RAN is gNB or ng-eNB. 5GC has logical nodes AMF, UPF, and SMF.

[0212] For example, the gNB and ng-eNB host the following main functions: - Radio Resource Management functions such as Radio Bearer Control, Radio Admission Control, Connection Mobility Control, dynamic allocation (scheduling) of resources to UEs in both uplink and downlink; - IP header compression, encryption, and integrity protection of data; - AMF selection at UE attach time if routing to the AMF cannot be determined from the information provided by the UE; - Routing of user plane data towards UPF; - Routing of control plane information towards AMF; - Setting up and tearing down connections; - scheduling and sending of paging messages; - Scheduling and transmission of system broadcast information (originating from AMF or Operation, Admission, Maintenance (OAM) Function); - Configuring measurements and measurement reporting for mobility and scheduling; - Transport level packet marking in the uplink; - Session management; - Network slicing support; - QoS flow management and mapping to data radio bearers; - Support for UEs in RRC_INACTIVE state; - NAS message delivery function; - Sharing of radio access networks; - Dual connectivity; - Close cooperation between NR and E-UTRA.

[0213] The Access and Mobility Management Function (AMF) hosts the following main functions: - Ability to terminate Non-Access Stratum (NAS) signaling; - NAS signaling security; - Access Stratum (AS) security control; - Core Network (CN) inter-node signaling for mobility between 3GPP access networks; - Reachability to idle mode UEs (including control and execution of paging retransmissions); - Managing the registration area; - Support for intra-system and inter-system mobility; - Access authentication; - Access authorization, including checking roaming privileges; - Mobility management control (subscription and policy); - Network slicing support; - Selection of Session Management Function (SMF).

[0214] Additionally, the User Plane Function (UPF) hosts the following main functions: - Anchor points for intra-RAT / inter-RAT mobility (if applicable); - External PDU (Protocol Data Unit) session points for interconnection with data networks; - Packet routing and forwarding; - Packet inspection and policy rule enforcement for the user plane part; - Traffic usage reporting; - uplink classifier to support routing of traffic flows to the data network; - Branching Point for supporting multi-homed PDU sessions; - QoS processing for the user plane (e.g., packet filtering, gating, UL / DL rate enforcement); - Verification of uplink traffic (mapping for QoS flows of SDFs); - Downlink packet buffering and triggering function for downlink data notification.

[0215] Finally, the Session Management Function (SMF) hosts the following main functions: - Session management; - IP address allocation and management for the UE; - Selection and control of the UPF; - Traffic steering setting function in the User Plane Function (UPF) for routing traffic to the appropriate destination; - Enforcement of control plane policies and QoS; - Notification of downlink data.

[0216] <Procedures for RRC connection setup and reconfiguration> Figure 16 shows some of the interactions between the UE, gNB, and AMF (5GC entity) in the NAS part when the UE moves from RRC_IDLE to RRC_CONNECTED (see TS 38.300 v15.6.0).

[0217] RRC is a higher layer signaling protocol used to configure the UE and the gNB. With this transition, the AMF prepares UE context data (including, for example, PDU session context, security keys, UE radio capabilities, and UE security capabilities) and sends it to the gNB with an INITIAL CONTEXT SETUP REQUEST. The gNB then activates AS security together with the UE. This is done by the gNB sending a SecurityModeCommand message to the UE, and the UE responding with a SecurityModeComplete message. The gNB then sends an RRCReconfiguration message to the UE, and upon receiving an RRCReconfigurationComplete from the UE, the gNB reconfigures the UE to set up a Signaling Radio Bearer 2 (SRB2) and a Data Radio Bearer (DRB). For signaling-only connections, the RRCReconfiguration steps are omitted because SRB2 and DRB are not set up. Finally, the gNB notifies the AMF that the setup procedure is complete with an INITIAL CONTEXT SETUP RESPONSE.

[0218] Therefore, the present disclosure provides a 5th Generation Core (5GC) entity (e.g., AMF, SMF, etc.) that includes: control circuitry that, in operation, establishes a Next Generation (NG) connection with a gNodeB; and a transmitter that, in operation, transmits an initial context setup message to the gNodeB via the NG connection so that a signaling radio bearer between the gNodeB and a user equipment (UE) is set up. Specifically, the gNodeB transmits Radio Resource Control (RRC) signaling that includes a resource allocation configuration information element (IE) to the UE via the signaling radio bearer. Then, the UE performs uplink transmission or downlink reception based on the resource allocation configuration.

[0219] <IMT usage scenarios from 2020 onwards> Figure 17 shows some use cases for 5G NR. The 3rd Generation Partnership Project 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 specifications for enhanced mobile broadband (eMBB) has been completed. Current and future work includes standardization for ultra-reliable and low-latency communications (URLLC) and massive machine-type communications (mMTC), in addition to expanding support for eMBB. Figure 17 shows some example use scenarios envisioned for IMT beyond 2020 (see, for example, ITU-R M.2083 Figure 2).

[0220] URLLC use cases have stringent performance requirements, such as throughput, latency, and availability. URLLC use cases are envisioned as one of the enabling technologies for future applications, such as wireless control of industrial production or manufacturing processes, remote medical surgery, automated power transmission and distribution in smart grids, and road safety. URLLC's ultra-high reliability is supported by identifying technologies that meet the requirements set by TR 38.913. Key requirements for NR URLLC in Release 15 include a target user plane latency of 0.5 ms on the uplink (UL) and 0.5 ms on the downlink (DL). The overall URLLC requirement for a single packet transmission is a block error rate (BLER) of 1E-5 for a 32-byte packet size at a user plane latency of 1 ms.

[0221] From a physical layer perspective, reliability can be improved in many possible ways. Current reliability improvement room includes defining a separate CQI table for URLLC, more compact DCI formats, PDCCH repetition, etc. However, this room can be expanded to achieve ultra-high reliability as NR (with respect to the key requirements of NR URLLC) becomes more stable and developed. Specific use cases for NR URLLC in Release 15 include augmented reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0222] Additionally, technology enhancements targeted by NR URLLC aim to improve latency and reliability. Technology enhancements for latency improvement include configurable numerology, non-slot-based scheduling with flexible mapping, grant-free (configured grant) uplink, slot-level repetition in the data channel, and preemption in the downlink. Preemption means that a transmission with previously allocated resources is stopped and the allocated resources are used for another transmission with a later requested lower latency / higher priority requirement. Thus, a previously allowed transmission is preempted by a later transmission. Preemption is applicable regardless of the specific service type. For example, a transmission of service type A (URLLC) may be preempted by a transmission of service type B (eMBB, etc.). Technology enhancements for reliability improvement include dedicated CQI / MCS tables for a target BLER of 1E-5.

[0223] The use case for massive machine-type communication (mMTC) is characterized by a very large number of connected devices that typically transmit relatively small amounts of data that are not sensitive to latency. These devices are required to be low cost and have very long battery life. From an NR perspective, using very narrow bandwidth portions is one solution that saves power and allows for long battery life from the UE perspective.

[0224] As mentioned above, the scope of reliability improvement in NR is expected to be broader. One of the key requirements for all cases, for example for URLLC and mMTC, is high or ultra-high reliability. Several mechanisms can improve reliability from a radio perspective and a 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 improvement regardless of the specific communication scenario.

[0225] For NR URLLC, further use cases with more stringent requirements are envisioned, such as factory automation, transportation, and power distribution: high reliability (up to 10-6 level), high availability, packet sizes up to 256 bytes, and time synchronization down to a few μs (depending on the use case, the value can be 1 μs or a few μs depending on the frequency range and low latency in the 0.5 ms to 1 ms range (e.g., 0.5 ms latency on the targeted user plane)).

[0226] Furthermore, for NR URLLC, several technical enhancements may be available from the perspective of the physical layer. These technical enhancements include enhancements to the PDCCH (Physical Downlink Control Channel) related to compact DCI, repetition of the PDCCH, and increased monitoring of the PDCCH. Also, the enhancement of UCI (Uplink Control Information) is related to the enhancement of enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback. Additionally, enhancements to the PUSCH related to mini-slot level hopping, and enhancements to retransmission / repetition may be available. The term "mini-slot" refers to a Transmission Time Interval (TTI) that contains fewer symbols than a slot (a slot has 14 symbols).[[ID=!]]

[0227] <QoS Control> The QoS (Quality of Service) model of 5G is based on QoS flows and supports both QoS flows that require a guaranteed flow bit rate (GBR: Guaranteed Bit Rate QoS flows) and QoS flows that do not require a guaranteed flow bit rate (non-GBR QoS flows). Therefore, at the NAS level, a QoS flow is the finest granularity QoS differentiation in a PDU session. A QoS flow is identified within a PDU session by a QoS Flow ID (QFI: QoS Flow ID) that is carried in an encapsulation header via the NG-U interface.

[0228] For each UE, the 5GC establishes one or more PDU sessions. For each UE, the NG-RAN establishes at least one Data Radio Bearer (DRB) for each PDU session, e.g., as shown above with reference to Figure 16. Additional DRBs for the QoS flows of that PDU session can be configured later (when this is up to the NG-RAN). The NG-RAN maps packets belonging to different PDU sessions to different DRBs. NAS-level packet filters in the UE and the 5GC associate UL packets and DL packets with QoS flows, while AS-level mapping rules in the UE and the NG-RAN associate UL QoS flows and DL QoS flows with DRBs.

[0229] Figure 18 shows the non-roaming reference architecture for 5G NR (see TS 23.501 v16.1.0, section 4.23). An Application Function (AF) (e.g., an external application server hosting 5G services, as illustrated in Figure 17) interacts with the 3GPP core network to provide services. For example, it accesses a Network Exposure Function (NEF) to support applications that affect traffic routing, or interacts with a policy framework (see Policy Control Function (PCF)) for policy control (e.g., QoS control). Based on the operator's deployment, Application Functions that are considered trusted by the operator can interact directly with the relevant Network Functions. Application Functions that are not authorized by the operator to directly access Network Functions interact with the relevant Network Functions using an external exposure framework via the NEF.

[0230] Figure 18 further illustrates further functional units of the 5G architecture, namely, Network Slice Selection Function (NSSF), Network Repository Function (NRF), Unified Data Management (UDM), Authentication Server Function (AUSF), Access and Mobility Management Function (AMF), Session Management Function (SMF), and Data Network (DN, e.g., operator-provided services, Internet access, or third-party services). All or part of the core network functions and application services may be deployed and run in a cloud computing environment.

[0231] Therefore, the present disclosure provides an application server (e.g., an AF in a 5G architecture) comprising: a transmitter that, in operation, sends a request including QoS requirements for at least one of a URLLC service, an eMMB service, and an mMTC service to at least one of 5GC functions (e.g., an NEF, an AMF, an SMF, a PCF, an UPF, etc.) to establish a PDU session including a radio bearer between a gNodeB and a UE according to the QoS requirements; and a control circuit that, in operation, performs a service using the established PDU session.

[0232] The present disclosure can be realized by software, hardware, or software linked to hardware. Each functional block used in the description of the above embodiments may be partially or entirely realized as an LSI, which is an integrated circuit, and each process described in the above embodiments may be partially or entirely controlled by a single LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. The LSI may have data input and output. Depending on the degree of integration, the LSI may be called an IC, system LSI, super LSI, or ultra LSI.

[0233] The integrated circuit method is not limited to LSI, but may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. Also, a field programmable gate array (FPGA) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells within the LSI, may be used. The present disclosure may be realized as digital processing or analog processing.

[0234] Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, it is natural that such technology can be used to integrate functional blocks. The application of biotechnology is also a possibility.

[0235] The present disclosure may be implemented in any type of apparatus, device, or system (collectively referred to as a communications apparatus) that has a communications function. The communications apparatus may include a wireless transceiver and processing / control circuitry. The wireless transceiver may include a receiver and a transmitter, or both functions. The wireless transceiver (transmitter and receiver) may include a radio frequency (RF) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or the like. Non-limiting examples of communication devices include telephones (e.g., cell phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine devices, communication-enabled vehicles or mobile transportation (e.g., cars, airplanes, ships), and combinations of the above devices.

[0236] Communications equipment is not limited to portable or mobile equipment, but also includes non-portable or fixed equipment, devices, and systems of any kind, such as smart home devices (such as appliances, lighting equipment, smart meters or metering devices, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0237] Communications include data communications via cellular systems, wireless LAN systems, communications satellite systems, etc., as well as data communications via combinations of these.

[0238] A communications apparatus also includes devices such as controllers and sensors connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications apparatus.

[0239] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these.

[0240] A terminal according to one embodiment of the present disclosure has a receiving circuit that receives a synchronization signal, and a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block, and the control circuit changes the correspondence between a first reception timing and a second reception timing of the synchronization signal block.

[0241] In one embodiment of the present disclosure, the control circuit shifts the index of the synchronization signal block relative to the transmission position of the synchronization signal block by a fixed amount to change the correspondence.

[0242] In one embodiment of the present disclosure, the control circuit shifts the index of the synchronization signal block relative to the transmission position of the synchronization signal block according to a system frame number, thereby changing the correspondence.

[0243] In one embodiment of the present disclosure, the control circuit reverses the correspondence relationship between the index of the synchronization signal block and the transmission position of the synchronization signal block between the first reception timing and the second reception timing.

[0244] In one embodiment of the present disclosure, the control circuit inputs the system frame number into a pseudo-random number formula to change the correspondence.

[0245] In one embodiment of the present disclosure, the control circuit uses the system frame number to refer to a table showing the correspondence relationship for each system frame number, and changes the correspondence relationship.

[0246] In one embodiment of the present disclosure, the control circuit changes the correspondence using a cell identifier.

[0247] In one embodiment of the present disclosure, the control circuit switches the method of changing the correspondence relationship using a cell identifier or information included in a System Information Block (SIB).

[0248] In one embodiment of the present disclosure, the control circuit changes the amount of the fixed amount shift based on information included in the SIB.

[0249] In one embodiment of the present disclosure, the control circuit changes the shift amount of the shift based on information included in the SIB.

[0250] In one embodiment of the present disclosure, the control circuit further changes the correspondence based on a physical downlink control channel (PDCCH) or a physical downlink shared channel (PDSCH).

[0251] A base station according to one embodiment of the present disclosure includes a transmission circuit that transmits a synchronization signal, and a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block, and the control circuit changes the correspondence between a first transmission timing and a second transmission timing of the synchronization signal block.

[0252] In a communication method according to one embodiment of the present disclosure, a terminal receives a synchronization signal, determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block, and changes the correspondence between a first reception timing and a second reception timing of the synchronization signal block.

[0253] In a communication method according to one embodiment of the present disclosure, a base station transmits a synchronization signal, determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block, and changes the correspondence between a first transmission timing and a second transmission timing of the synchronization signal block.

[0254] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2021-056210, filed on March 29, 2021, are incorporated herein by reference in their entirety. [Industrial Applicability]

[0255] One aspect of the present disclosure is useful in wireless communication systems. [Explanation of symbols]

[0256] 10 base station 11 Control section 12 SSB index determination section 13 SSB generation section 14 Transmission processing unit 15 Transmission beam control unit 16 Transmit RF section 17 Antenna 18 LBT judgment section 19 Receiving beam control section 20 Receiving RF section 21 Receiving processing unit 22 Common signal generation section 50 devices 51 RF section 52 Receiving processing unit 53 SSB decoding section 54 SSB index determination unit 55 SSB selection section 56 Preamble resource determination section 57 LBT judgment section 58 Transmission processing unit 59 Common signal decoding unit

Claims

1. a receiving circuit for receiving a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first reception timing and the second reception timing of the synchronization signal block; the control circuit inputs the system frame number into a pseudo-random number formula to change the correspondence; Terminal.

2. A receiving circuit for receiving a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first reception timing and the second reception timing of the synchronization signal block; the control circuit changes the correspondence relationship using a cell identifier. Terminal.

3. A receiving circuit for receiving a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first reception timing and the second reception timing of the synchronization signal block; The control circuit switches the method of changing the correspondence relationship using a cell identifier or information included in a System Information Block (SIB). Terminal.

4. A receiving circuit for receiving a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first reception timing and the second reception timing of the synchronization signal block; the control circuit shifts an index of the synchronization signal block relative to a transmission position of the synchronization signal block by a fixed amount to change the correspondence; The control circuit changes the amount of the fixed amount shift based on information included in the SIB. Terminal.

5. A receiving circuit for receiving a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first reception timing and the second reception timing of the synchronization signal block; the control circuit shifts an index of the synchronization signal block relative to a transmission position of the synchronization signal block according to a system frame number, thereby changing the correspondence; The control circuit changes the shift amount of the shift based on information included in the SIB. Terminal.

6. A receiving circuit for receiving a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first reception timing and the second reception timing of the synchronization signal block; The control circuit further changes the correspondence based on a physical downlink control channel (PDCCH) or a physical downlink shared channel (PDSCH). Terminal.

7. A transmission circuit for transmitting a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first transmission timing and the second transmission timing of the synchronization signal block; the control circuit inputs the system frame number into a pseudo-random number formula to change the correspondence; Base station.

8. A transmission circuit for transmitting a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first transmission timing and the second transmission timing of the synchronization signal block; the control circuit changes the correspondence relationship using a cell identifier. Base station.

9. A transmission circuit for transmitting a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first transmission timing and the second transmission timing of the synchronization signal block; The control circuit switches the method of changing the correspondence relationship using a cell identifier or information included in a System Information Block (SIB). Base station.

10. A transmission circuit for transmitting a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first transmission timing and the second transmission timing of the synchronization signal block; the control circuit shifts an index of the synchronization signal block relative to a transmission position of the synchronization signal block by a fixed amount to change the correspondence; The control circuit changes the amount of the fixed amount shift based on information included in the SIB. Base station.

11. A transmitter circuit for transmitting a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first transmission timing and the second transmission timing of the synchronization signal block; the control circuit shifts an index of the synchronization signal block relative to a transmission position of the synchronization signal block according to a system frame number, thereby changing the correspondence; The control circuit changes the shift amount of the shift based on information included in the SIB. Base station.

12. A transmitter circuit for transmitting a synchronization signal; a control circuit that determines a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; and the control circuit changes the correspondence between the first transmission timing and the second transmission timing of the synchronization signal block; The control circuit further changes the correspondence based on a physical downlink control channel (PDCCH) or a physical downlink shared channel (PDSCH). Base station.

13. The terminal is Receives a synchronization signal, determining a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; changing the correspondence between the first reception timing and the second reception timing of the synchronization signal block; inputting the system frame number into a pseudo-random number formula to change the correspondence; Communication method.

14. The base station is Sends a synchronization signal, determining a correspondence between a transmission position of a synchronization signal block and an index of the synchronization signal block; changing the correspondence between the first transmission timing and the second transmission timing of the synchronization signal block; inputting the system frame number into a pseudo-random number formula to change the correspondence; Communication method.

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