Terminal, communication method and integrated circuit

Abstract

The purpose of the present invention is to improve the reception quality of a synchronization signal in a terminal. The terminal is equipped with: a reception circuit that receives a first synchronization signal block and a second synchronization signal block that is different from the first synchronization signal block in at least one of the sequence and the signal position; and a control circuit that performs a cell search on the basis of the first synchronization signal block and the second synchronization signal block.

Description

[Technical Field]

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

[0002] A communication system called the fifth-generation mobile communication system (5G) is currently under consideration. The 3rd Generation Partnership Project (3GPP), an international standardization organization, is studying the advancement of the 5G communication system from the perspectives of both the advancement of the LTE / LTE-Advanced system and New Radio Access Technology (also referred to as New RAT or NR), a new method that is not necessarily backward compatible with the LTE / LTE-Advanced system (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] RP-181726, "Revised WID on New Radio Access Technology", NTT DOCOMO, September 2018 [Non-patent document 2] RP-193240, "New SID on NR coverage enhancement", China Telecom, December 2019 [Non-patent document 3] RP-193238, "New SID on Support of Reduced Capability NR Devices", Ericsson, December 2019 Summary of the Invention

[0004] However, there is room for further study on methods for improving the reception quality of synchronization signals at terminals.

[0005] Non-limiting examples of the present disclosure contribute to providing a terminal, a base station, and a communication method that can improve the reception quality of a synchronization signal in a terminal.

[0006] A terminal according to one embodiment of the present disclosure includes a receiving circuit that receives a first synchronization signal block and a second synchronization signal block that differs from the first synchronization signal block in at least one of a sequence and a signal arrangement, and a control circuit that performs a cell search based on the first synchronization signal block and the second synchronization signal block.

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

[0008] According to an embodiment of the present disclosure, the reception quality of a synchronization signal at a terminal can be improved.

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

[0010] [Figure 1] Diagram showing an example of the configuration of Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) Block (SSB) [Figure 2] An example of beam sweeping [Figure 3] An example of beam sweeping [Figure 4] A diagram showing an example of a legacy SSB and an additional SSB [Figure 5]Block diagram showing an example of the configuration of a portion of a base station [Figure 6] Block diagram showing an example of the configuration of a part of a terminal [Figure 7] Block diagram showing an example of the configuration of a base station [Figure 8] Block diagram showing an example of a terminal configuration [Figure 9] Flowchart showing an example of the operation of a base station and a terminal [Figure 10] FIG. 1 shows an example of a legacy SSB and an additional SSB according to operation example 1. [Figure 11] FIG. 10 shows an example of a legacy SSB and an additional SSB according to operation example 2. [Figure 12] FIG. 10 shows an example of a legacy SSB and an additional SSB according to operation example 2. [Figure 13] FIG. 10 shows an example of a legacy SSB and an additional SSB according to operation example 3. [Figure 14] FIG. 10 shows an example of a legacy SSB and an additional SSB according to operation example 4. [Figure 15] FIG. 10 shows an example of a legacy SSB and an additional SSB according to operation example 4. [Figure 16] FIG. 10 shows an example of a legacy SSB and an additional SSB according to operation example 4. [Figure 17] A diagram showing an example of multiplexing an additional SSB and a Type 0 Physical Downlink Control Channel (PDCCH). [Figure 18] FIG. 1 shows an example of multiplexing an additional SSB and a Type 0 PDCCH. [Figure 19] A diagram showing an example of legacy SSB and additional SSB settings [Figure 20] A diagram showing an example of legacy SSB and additional SSB settings [Figure 21] A diagram showing an example of legacy SSB and additional SSB settings [Figure 22] A diagram showing an example of legacy SSB and additional SSB configuration in unlicensed bands [Figure 23] Diagram of an example architecture of a 3GPP NR system [Figure 24] Schematic diagram showing functional separation between NG-RAN and 5GC [Figure 25] Sequence diagram of the Radio Resource Control (RRC) connection setup / reconfiguration procedure [Figure 26] Schematic diagram showing usage scenarios for enhanced Mobile BroadBand (eMBB), massive Machine Type Communications (mMTC), and Ultra Reliable and Low Latency Communications (URLLC). [Figure 27] Block diagram illustrating an exemplary 5G system architecture for a non-roaming scenario DETAILED DESCRIPTION OF THE INVENTION

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

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

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

[0014] [Reduced Capability NR Devices] For example, in Release 17 (hereinafter referred to as Rel-17 NR), specifications are expected to be formulated to realize terminals (e.g., also referred to as NR terminals) (or CE: Coverage Enhancement) with a wider communication area (or coverage) than terminals (e.g., mobile stations or User Equipment (UE)) that support Release 15 or 16 (hereinafter referred to as Rel-15 / 16NR) (see, for example, Non-Patent Document 2).

[0015] Furthermore, in Rel-17, specifications are expected to be formulated to realize terminals (e.g., NR terminals) that support a variety of use cases by reducing power consumption or costs by limiting some functions or performance compared to Rel-15 / 16NR (see, for example, Non-Patent Document 3). Note that such terminals are sometimes called, for example, Reduced Capability NR Devices, RedCap, RedCap terminals, NR-Lite, or NR-Light.

[0016] [Cell search by device] A terminal that is not connected to a cell (e.g., also referred to as an RRC_IDLE mode terminal) may find a cell by using, for example, a synchronization signal block (SS / PBCH: Synchronization Signal (SS) Block) transmitted from a base station. For example, the procedure for finding a cell is called a cell search.

[0017] In the cell search, the terminal may perform, for example, symbol synchronization, identification of a cell ID (for example, PCI: Physical-layer Cell Identities), identification of a slot number, and identification of a frame number.

[0018] FIG. 1 is a diagram showing an example of the configuration of an SSB. As shown in FIG. 1, an SSB may be a set of signals (or a signal block) including a primary synchronization signal (PSS: Primary SS or referred to as a first synchronization signal), a secondary synchronization signal (SSS: Secondary SS or referred to as a second synchronization signal), a broadcast channel (PBCH or referred to as a broadcast signal), and a reference signal for the PBCH (e.g., a Demodulation Reference Signal (DMRS)). For example, as shown in FIG. 1, the PSS may be located at the beginning of the SSB (e.g., the 0th symbol), the SSS may be located in the second symbol of the SSB, and the PBCH may be located in the first to third symbols of the SSB. Furthermore, the DMRS for the PBCH may be located, for example, in the PBCH region of the first to third symbols of the SSB.

[0019] For example, the SSB may be transmitted from the base station at a certain time timing (for example, at a specified time interval). The terminal may detect and decode the PSS, SSS, DMRS for PBCH, and PBCH in this order.

[0020] An example of cell search processing using SSB in a terminal will be described below.

[0021] (1) PSS detection The terminal may, for example, attempt to detect the PSS. As an example, the PSS may be transmitted using one of three types of sequences (e.g., length 127) known to the terminal. The terminal, for example, does not know the timing at which the PSS is transmitted. The terminal may, for example, calculate the correlation value between a received signal in a certain time resource (e.g., symbol) and a replica of a known sequence for the PSS. The terminal may determine that symbol synchronization has been achieved, for example, when it detects a symbol with a high correlation value with any of the replicas (e.g., a symbol with a correlation value equal to or greater than a threshold). Furthermore, the terminal may, for example, determine a parameter (e.g., N ID (2) ) value may be specified.

[0022] (2) SSS detection The terminal may, for example, attempt to detect the SSS. As an example, the SSS may be transmitted in the symbol (for example, the second symbol of the SSB) two symbols after the symbol (for example, the 0th symbol of the SSB) in which the PSS detected by the terminal is located, using one of 336 types of sequences (for example, of length 127) known to the terminal. The terminal may, for example, calculate the correlation value between the received signal in the symbol in which the SSS may be transmitted and a replica of the known sequence for the SSS. The terminal may, for example, determine that a sequence with a high correlation value (for example, a sequence with a correlation value equal to or greater than a threshold) is the SSS sequence. Furthermore, the terminal may, for example, determine a parameter (N ID(1) ) value may be specified.

[0023] The terminal may then identify a cell ID (for example, PCI) based on the identified PSS sequence and SSS sequence. ID(1) + N ID(2) " may be calculated as follows.

[0024] (3) PBCH DMRS detection The terminal may, for example, attempt to detect the PBCH DMRS. The PBCH DMRS may, for example, be allocated to any of the symbols (e.g., the first to third symbols of an SSB) from the symbol (e.g., the second symbol of an SSB) in which the detected SSS is allocated to to the symbol (e.g., the first to third symbols of an SSB). The PBCH DMRS sequence may differ, for example, depending on part or all of a bit string indicating an SSB index that can identify a slot number. Furthermore, the PBCH DMRS sequence may differ, for example, depending on a half frame bit (e.g., information indicating that the received SSB is allocated to the first half (e.g., first half frame) or second half (e.g., second half frame) of a radio frame).

[0025] The terminal may, for example, calculate a correlation value between a received DMRS signal in a symbol in which the PBCH DMRS may be transmitted and a replica that differs depending on the slot number, and determine a sequence with a high correlation value (for example, a sequence with a correlation value equal to or greater than a threshold) as a DMRS sequence. The terminal may, for example, obtain a part or all of a bit string indicating an SSB index based on the detected DMRS sequence. The terminal may also, for example, obtain a half frame bit based on the detected DMRS sequence. The terminal may also, for example, estimate a channel (propagation path characteristics) using the detected PBCH DMRS.

[0026] (4) PBCH decoding The terminal may decode the PBCH arranged in the same symbol as the PBCH DMRS, for example, based on the channel estimate. The terminal may also obtain, for example, a half frame bit and a radio frame number (e.g., SFN: System Frame Number) included in the PBCH. The terminal may also obtain a portion of the bits indicating the SSB index. The terminal may then identify the time position (e.g., symbol, slot, or frame) of the received SSB based on, for example, the values ​​of the SSB index, SFN, and half frame bit.

[0027] An example of the cell search process has been described above.

[0028] [beam sweeping] A base station can transmit multiple SSBs with different indexes at different times. For example, the base station may set different SSB indexes (e.g., SSB index = 0 to 3 in FIG. 2) for SSBs transmitted at different times and transmit the SSBs using different beams for each SSB index. This process is also called beam sweeping.

[0029] A set of multiple SSBs including SSBs with different SSB indices is also called an “SSB burst set (or SSB burst, SS burst).” The SSB burst set may be transmitted, for example, within a certain half frame (e.g., the first or second half of a frame).

[0030] For example, a terminal may report to a base station the SSB index of one SSB with high reception strength (or reception quality) among the detected SSBs (e.g., one SSB with the highest reception strength). FIG. 3 is a diagram showing an example of beam sweeping. For example, one or more terminals on the left side of FIG. 3 may select SSB index 1 and transmit a preamble to the base station on a resource associated with SSB index 1 (e.g., a Physical Random Access Channel (PRACH) resource). Similarly, one or more terminals on the right side of FIG. 3 may select SSB index 2 and transmit a preamble to the base station on a PRACH resource associated with SSB index 2.

[0031] [Coverage Extension] According to Non-Patent Document 2, the specification of a technology (CE: Coverage Enhancement) that will achieve wider coverage than the initial release of NR is being considered.

[0032] Furthermore, according to Non-Patent Document 3, for example, the specification of a technology (e.g., Reduced Capability) that will realize a terminal at a lower cost than the initial release of NR is being considered. One example of a cost-saving technology is, for example, reducing (in other words, limiting) the number of antennas equipped in a terminal or the bandwidth it supports.

[0033] However, these technologies may reduce coverage. Therefore, in the future, technologies to compensate for coverage may be considered. For example, SSB coverage extension technologies may be considered to realize terminals with coverage enhancement or reduced capability.

[0034] One technique for extending SSB coverage is, for example, duplicating (or repetition) an SSB (or SSB burst set) specified in Rel-15 / 16 and transmitting additional SSBs (or SSB burst sets) in different time or frequency resources, as shown in Figure 4. This method allows, for example, a terminal that supports Rel-17 or later (e.g., a terminal to which RedCap or CE is applied) to receive more SSBs than a terminal that supports Rel-15 / 16 (e.g., referred to as a Rel-15 / 16 terminal).

[0035] However, other terminals (e.g., Rel-15 / 16 terminals) that are different from terminals to which the above-mentioned CE or RedCap is applied may receive (or detect) the PSS of the SSB specified in Rel-15 / 16 without distinguishing between the PSS of the additional SSB before connecting to a cell. For example, other terminals may mistakenly detect the additional SSB as an SSB specified in Rel-15 / 16, resulting in a synchronization failure.

[0036] In one embodiment of the present disclosure, for example, a method is described for extending SSB coverage for terminals to which CE or RedCap is applied, and suppressing synchronization failures in Rel-15 / 16 terminals or terminals from Rel-17 onwards to which CE or RedCap is not applied.

[0037] For example, in one embodiment of the present disclosure, a terminal to which coverage extension (CE) technology can be applied (e.g., a terminal of Rel-17 or later to which CE or RedCap specification technology is applied) may receive additional SSBs in addition to SSBs defined in the Rel-15 / 16 specifications (e.g., referred to as "legacy SSBs") when receiving SSBs.

[0038] In one embodiment of the present disclosure, the additional SSB may include at least one signal selected from the PSS, SSS, PBCH, and DMRS for PBCH. The additional SSB may be allocated to resources that are different from the legacy SSB in terms of at least one of time resources and frequency resources. Furthermore, the additional SSB may be allocated to resources that are different from the legacy SSB in terms of at least one of sequence and signal allocation.

[0039] As a result, in one embodiment of the present disclosure, for example, the number of times that a terminal to which CE can be applied can receive SSBs can be increased, thereby expanding the receivable coverage. Also, in one embodiment of the present disclosure, for example, terminals other than terminals to which CE can be applied (for example, Rel-15 / 16 terminals, or terminals in Rel-17 or later that do not apply CE or technology established in the RedCap specifications) are less likely to erroneously detect additional SSBs, thereby reducing synchronization failures.

[0040] In the following description, for convenience, when simply referring to a "terminal" or "terminal 200" described later, it means a terminal to which CE can be applied. Also, in the following description, for convenience, when referring to an "other terminal," it means, for example, a Rel-15 / 16 terminal or a terminal that is Rel-17 or later and to which the technology established in the CE or RedCap specifications is not applied.

[0041] Furthermore, in the following description, the "signal arrangement" in an SSB may mean, for example, at least one of the order of signals included in the SSB and the presence or absence of a signal.

[0042] [Communication System Overview] The communication system according to this embodiment includes base station 100 and terminal 200.

[0043] Fig. 5 is a block diagram showing an example of the configuration of a portion of base station 100 according to this embodiment. In base station 100 shown in Fig. 5, control unit 101 (e.g., corresponding to a control circuit) controls the generation of a first synchronization signal block (e.g., a legacy SSB) and a second synchronization signal block (e.g., an additional SSB) that differs from the first synchronization signal block in at least one of the sequence and signal allocation. Transmitting unit 105 (e.g., corresponding to a transmitting circuit) transmits the first synchronization signal block and the second synchronization signal block.

[0044] Fig. 6 is a block diagram showing an example configuration of a portion of terminal 200 according to this embodiment. In terminal 200 shown in Fig. 6, receiver 202 (e.g., equivalent to a receiver circuit) receives a first synchronization signal block (e.g., legacy SSB) and a second synchronization signal block (e.g., additional SSB) that differs from the first synchronization signal block in at least one of sequence and signal allocation. Controller 208 (e.g., equivalent to a control circuit) performs a cell search based on the first synchronization signal block and the second synchronization signal block.

[0045] [Base station configuration] Fig. 7 is a block diagram showing an example configuration of base station 100 according to this embodiment. In Fig. 7, base station 100 has control unit 101, signal generation unit 102, coding and modulation unit 103, signal mapping unit 104, transmission unit 105, antenna 106, reception unit 107, and demodulation and decoding unit 108.

[0046] The control unit 101 may determine, for example, at least one of the signals included in the legacy SSBs and additional SSBs (for example, DMRS for PSS, SSS, or PBCH) or the DMRS sequences included in the downlink data (for example, PDSCH: Physical Downlink Shared Channel), and the signal mapping (for example, time resources and frequency resources). The control unit 101 may, for example, output information (or instructions) related to the determined sequence of each signal to the signal generation unit 102, and output information (or instructions) related to the determined mapping resources of each signal to the signal mapping unit 104.

[0047] The signal generating section 102 may generate a PSS, an SSS, and a DMRS based on information about sequences input from the control section 101, and output the generated signals to the signal mapping section 104, for example.

[0048] The encoding and modulation section 103 may, for example, perform error correction encoding and modulation on the downlink data and broadcast information, and output the modulated signals to the signal mapping section 104 .

[0049] The signal mapping unit 104 may identify resources for each channel or signal based on, for example, pre-defined or pre-configured information. The signal mapping unit 104 may map the signals (e.g., PSS, SSS, and DMRS) input from the signal generation unit 102 and the signals input from the coding and modulation unit 103 to resources based on, for example, the identified resources and information on resources input from the control unit 101.

[0050] For example, the signal mapping unit 104 may map the PSS to the PSS resource, map the SSS to the SSS resource, map the DMRS to the DMRS resource in the PDSCH and PBCH, map the downlink data to the PDSCH resource, and map the broadcast information to the PBCH resource.

[0051] The signal mapping unit 104 outputs the signals mapped to each resource to the transmitting unit 105 .

[0052] For example, the transmitting unit 105 performs radio transmission processing such as frequency conversion using a carrier wave on the signal input from the signal mapping unit 104, and outputs the signal after radio transmission processing to the antenna .

[0053] Antenna 106 radiates the signal input from transmitter 105 (in other words, the downlink signal) toward terminal 200. Antenna 106 also receives the uplink signal transmitted from terminal 200 and outputs it to receiver 107.

[0054] The uplink signal may be, for example, a signal of a channel such as an uplink data channel (e.g., a Physical Uplink Shared Channel (PUSCH)), an uplink control channel (e.g., a Physical Uplink Control Channel (PUCCH)), or a random access channel (e.g., a Physical Random Access Channel (PRACH)).

[0055] Receiving section 107 performs radio reception processing such as frequency conversion on the signal input from antenna 106, and outputs the signal after radio reception processing to demodulation and decoding section 108.

[0056] The demodulation / decoding unit 108 demodulates and decodes the signal input from the receiving unit 107, for example, and outputs an uplink signal.

[0057] [Device configuration] FIG. 8 is a block diagram showing an example of the configuration of terminal 200 according to this embodiment.

[0058] In FIG. 8 , terminal 200 includes antenna 201, receiving unit 202, signal separating unit 203, signal detecting unit 204, channel estimating unit 205, demodulating and decoding unit 206, broadcast information receiving unit 207, control unit 208, coding and modulating unit 209, and transmitting unit 210.

[0059] The antenna 201 receives a downlink signal transmitted by the base station 100 and outputs the signal to the receiving unit 202. The antenna 201 also radiates an uplink signal input from the transmitting unit 210 to the base station 100.

[0060] Receiving section 202 performs radio reception processing such as frequency conversion on the signal input from antenna 201 , and outputs the signal after radio reception processing to signal separating section 203 .

[0061] Signal separation unit 203 may identify resources for each channel or signal, for example, based on pre-defined or pre-configured information. Based on the identified resources and an instruction from control unit 208, signal separation unit 203 extracts (in other words, separates) signals allocated to PDSCH resources and PBCH resources from the signals input from receiving unit 202, outputs the extracted signals to demodulation and decoding unit 206, and outputs the signals allocated to PSS resources and SSS resources and the signals allocated to DMRS resources in the PDSCH and PBCH to signal detection unit 204.

[0062] Signal detection section 204 may detect a PSS, SSS, or DMRS sequence from the signal input from signal separation section 203, for example, in accordance with an instruction from control section 208. For example, signal detection section 204 may perform correlation detection between sequence information (e.g., sequence replicas) input from control section 208 and the signal on each resource (e.g., any one of PSS, SSS, and DMRS resources) input from signal separation section 203. Signal detection section 204 may output, for example, information on sequences and timings having high correlation (e.g., a correlation value equal to or greater than a threshold) in the correlation detection to control section 208. Furthermore, signal detection section 204 may output the detected DMRS to channel estimation section 205, for example.

[0063] The channel estimation unit 205 may perform channel estimation for the PDSCH or PBCH using the DMRS input from the signal detection unit 204 , for example, and output the channel estimation value to the demodulation and decoding unit 206 .

[0064] The demodulation and decoding unit 206 obtains downlink data or broadcast information by demodulating and error-correcting decoding the signal input from the signal separation unit 203 (e.g., a signal on a PDSCH or PBCH resource) based on, for example, the channel estimation value input from the channel estimation unit 205. The demodulation and decoding unit 206 outputs the broadcast information obtained by decoding to the broadcast information receiving unit 207, for example.

[0065] The broadcast information receiving unit 207 extracts information included in the broadcast information input from the demodulation and decoding unit 206 (for example, information relating to the timing of each SSB signal), and outputs the extracted information to the control unit 208 .

[0066] The control unit 208 may perform control related to, for example, cell search. For example, the control unit 208 may instruct the signal separation unit 203 and the signal detection unit 204 on information related to signals to be separated or detected. For example, the control unit 208 may output information related to the resources of each signal including SSB to the signal separation unit 203 and output information related to detectable sequences to the signal detection unit 204 based on pre-defined or pre-configured information.

[0067] Furthermore, for example, the control unit 208 may identify a cell ID (e.g., PCI) based on information relating to the PSS or SSS sequence input from the signal detection unit 204. Furthermore, for example, the control unit 208 may identify the time position of the received SSB based on information relating to the timing and sequence of each detected signal input from the signal detection unit 204 and information relating to timing input from the broadcast information reception unit 207.

[0068] The coding and modulation unit 209 may, for example, perform coding and modulation on an uplink signal (for example, PUSCH, PUCCH or PRACH) and output the modulated signal to the transmission unit 210.

[0069] The transmitting unit 210 performs transmission processing such as frequency conversion on the signal input from the encoding and modulation unit 209 , and outputs the signal after the transmission processing to the antenna 201 .

[0070] [Example of Operation of Base Station 100 and Terminal 200] Next, an example of the operation of base station 100 and terminal 200 described above will be described.

[0071] <Example 1> In the first operational example, for example, at least one signal sequence among the PSS, SSS, and DMRS for PBCH allocated to the legacy SSB and the additional SSB may be different from each other.

[0072] FIG. 9 is a flowchart showing an example of processing by the base station 100 and the terminal 200.

[0073] (S101) Terminal 200 may determine sequences and resources (eg, time resources and frequency resources) for legacy SSBs and additional SSBs based on predefined or configured information, for example.

[0074] (S102) Base station 100 may transmit, for example, legacy SSBs and additional SSBs to terminal 200. For example, base station 100 may transmit the legacy SSBs and additional SSBs in at least one of different time resources and frequency resources. Furthermore, base station 100 may set different sequences for the legacy SSBs and additional SSBs in at least one of the PSS, SSS, and PBCH.

[0075] Fig. 10 is a diagram showing an example of a legacy SSB and an additional SSB according to Operation Example 1. As shown in Fig. 10, the legacy SSB (for example, an SSB burst set) and the additional SSB (for example, an SSB burst set) may have different sequences in at least one of the PSS, SSS, and DMRS for PBCH.

[0076] (S103) Terminal 200 may, for example, attempt to detect a PSS. For example, terminal 200 may attempt correlation detection based on a sequence (e.g., a sequence replica) related to the detection of a PSS of a legacy SSB and a sequence (e.g., a sequence replica) related to the detection of a PSS of an additional SSB. For example, terminal 200 may identify the timing and sequence of any PSS included in the legacy SSB burst set or the additional SSB burst set.

[0077] (S104) Terminal 200 may, for example, attempt to detect an SSS. For example, if the PSS detected in the process of S103 is a legacy SSB, terminal 200 may attempt correlation detection based on a sequence (e.g., a sequence replica) that can be used for the SSS of the legacy SSB. On the other hand, for example, if the PSS detected in the process of S103 is an additional SSB, terminal 200 may attempt correlation detection based on a sequence (e.g., a sequence replica) that can be used for the SSS of the additional SSB. In this way, terminal 200 may identify any SSS included in the legacy SSB burst set or the additional SSB burst set.

[0078] For example, if an SSS is not detected, terminal 200 may return to the process of S103. For example, if an SSS is detected, terminal 200 may calculate a cell ID (for example, PCI) based on the identified PSS and SSS sequences. Note that hereinafter, "calculate" may be read as "determine" or "identify."

[0079] (S105) For example, if the PSS detected in the process of S103 is a legacy SSB, terminal 200 may attempt to detect the PBCH DMRS based on a sequence (e.g., a sequence replica) that can be used for the PBCH DMRS of the legacy SSB. Furthermore, for example, if the PSS detected in the process of S103 is an additional SSB, terminal 200 may attempt correlation detection based on a sequence (e.g., a sequence replica) that can be used for the PBCH DMRS of the additional SSB. In this way, terminal 200 may identify any PBCH DMRS sequence included in the legacy SSB burst set or the additional SSB burst set.

[0080] For example, if a DMRS is not detected, terminal 200 may return to the process of S103 or S104. For example, if a DMRS is detected, terminal 200 may calculate the SSB index (or part of the bits indicating the SSB index) based on the identified DMRS sequence for the PBCH. Furthermore, terminal 200 may estimate the channel using the detected DMRS for the PBCH.

[0081] (S106) Terminal 200 may decode the PBCH based on the channel estimation value obtained in the process of S105, for example. Terminal 200 may also obtain a half frame bit and a radio frame number (e.g., SFN) included in the PBCH, for example. Terminal 200 may also obtain a part of the bits indicating the SSB index, for example.

[0082] The terminal 200 may identify the time position of the received SSB based on, for example, the values ​​of the SSB index, SFN, and half frame bit.

[0083] (S107) Terminal 200 may transmit a preamble (e.g., a PRACH preamble) in a PRACH resource associated with the SSB index obtained in the processes of S105 and S106. In this case, if terminal 200 detects SSBs at multiple timings within the SSB burst set, terminal 200 may transmit the preamble based on the SSB index of an SSB with higher reception strength or reception quality among the multiple SSBs (e.g., the SSB with the highest reception strength or reception quality).

[0084] An example of the processing of base station 100 and terminal 200 has been described above.

[0085] In this way, terminal 200 that has learned the sequence of the additional SSB in the process of S101 can receive the additional SSB in addition to the legacy SSB, thereby improving the reception quality of the SSB and expanding the receivable coverage.

[0086] On the other hand, other terminals that do not know the sequence of the additional SSB will have difficulty detecting the sequence of the additional SSB, thereby reducing the possibility of false detection of the additional SSB.

[0087] Next, an example of generating an additional SSB in the first operational example will be described.

[0088] For example, the sequence for the additional SSB may be a sequence obtained by rearranging the sequence (eg, elements of the sequence) for the legacy SSB.

[0089] (Generation example 1) The base station 100 and the terminal 200 use, for example, a sequence d PSS The order of elements of (n) is reversed (in other words, inverted) to obtain a sequence d of length 127 in the PSS of the additional SSB. PSS_Add For example, the PSS sequence d of the additional SSB may be generated. PSS_Add (n) is the PSS sequence d for legacy SSB according to the following equation (1). PSS It can be a sequence in which the order of the elements in (n) is reversed.

number

[0090] (Generation example 2) The base station 100 and the terminal 200 use, for example, a sequence d PSS The elements of (n) are cyclically shifted (i.e., cyclically shifted) to obtain a sequence d of length 127 in the PSS of the additional SSB. PSS_Add For example, the PSS sequence d of the additional SSB may be generated. PSS_Add (n) is the PSS sequence d for legacy SSB according to the following equation (2). PSS It can be a sequence of elements (n) cyclically.

number

[0091] (Generation example 3) The base station 100 and the terminal 200 use, for example, a sequence d PSS The elements of (n) are interleaved to form a sequence d of length 127 in the PSS of the additional SSB. PSS_Add (n) may be generated.

[0092] For example, the PSS sequence of additional SSBs, d PSS_Add (n) is d PSS (n) is divided into a number (for example, 2), and each part is d PSS_Add For example, the PSS sequence d of the additional SSB may be arranged at equal intervals. PSS_Add (n) is the PSS sequence d for legacy SSB according to the following equation (3). PSS It can be a sequence in which elements (n) are interleaved.

number

[0093] The method of interleaving and shuffling the sequence in Generation Example 3 is not limited to the method based on Equation (3), and other methods may be used.

[0094] In each of the formulas (1) to (3), n and Δ may be integers.

[0095] According to generation examples 1 to 3, the additional SSB is generated based on a sequence specified for the legacy SSB, so that when generating the additional SSB, it is not necessary to generate a new sequence different from the sequence specified for the legacy SSB, thereby reducing the processing load on the base station 100 and the terminal 200.

[0096] In Generation Examples 1 to 3, a method for generating a PSS for an additional SSB has been described as an example, but an SSS or PBCH DMRS for an additional SSB may be generated using a method similar to that for a PSS. For example, each of Generation Examples 1 to 3 may be applied to sequence generation of an SSS or PBCH DMRS included in an additional SSB, not limited to a PSS. For example, the signal to which a different sequence is applied in an additional SSB than in a legacy SSB may be at least one of an SSS and a PBCH DMRS.

[0097] For example, in an additional SSB, the PSS sequence may be different from the PSS sequence of a legacy SSB, and the SSS and PBCH DMRS sequence may be common to the SSS and PBCH DMRS sequence of the legacy SSB. This makes it difficult for terminals other than terminal 200 to detect the PSS of the additional SSB when detecting the PSS, and therefore eliminates the need to detect the SSS and PBCH DMRS of the additional SSB, thereby reducing power consumption in the other terminals. Furthermore, by setting the SSS and PBCH DMRS sequence of the additional SSB to be common to the legacy SSB, it is possible to suppress changes from standards such as Rel-15 / 16.

[0098] Furthermore, for example, in an additional SSB, the PSS and SSS sequences may be different from the PSS and SSS sequences of a legacy SSB, and the PBCH DMRS sequence may be common to the PBCH DMRS sequence of the legacy SSB. This makes it difficult for terminals other than terminal 200 to detect the PSS or SSS of the additional SSB when detecting the PSS or SSS, and therefore eliminates the need to perform detection processing for the PBCH DMRS of the additional SSB, thereby reducing power consumption in the other terminals. Furthermore, by setting the PBCH DMRS sequence in the additional SSB to be common to the legacy SSB, it is possible to suppress changes from standards such as Rel-15 / 16.

[0099] Furthermore, for example, in an additional SSB, the PSS, SSS, and PBCH DMRS sequences may be different from the PSS, SSS, and PBCH DMRS sequences of a legacy SSB. This can reduce false detection of an additional SSB in terminals other than terminal 200, for example.

[0100] Furthermore, the additional SSB is not limited to cases where a signal to which a sequence different from that of the legacy SSB is applied includes a PSS; for example, a sequence different from that of the legacy SSB may be applied to any one or more combinations of the PSS, SSS, and DMRS for PBCH included in the additional SSB.

[0101] Furthermore, for example, among the PSS, SSS, and DMRS for PBCH included in the additional SSB, signals to which different sequences are applied may be dynamically switched with respect to the legacy SSB.

[0102] In addition, in Generation Examples 1 to 3, the case where the sequence for the additional SSB is generated based on the sequence for the legacy SSB has been described, but this is not limiting. For example, the sequence for one of the legacy SSB and the additional SSB may be a sequence obtained by rearranging elements of the sequence for the other of the legacy SSB and the additional SSB. For example, the sequence for the legacy SSB may be generated based on the sequence for the additional SSB.

[0103] <Example 2> In operation example 2, for example, the signal arrangement (e.g., signal arrangement order) of the PSS, SSS, and PBCH may be different between the legacy SSB and the additional SSB. For example, the position of at least one of the SSS and the PBCH (or the DMRS for the PBCH) relative to the position of the PSS within the additional SSB resource may be different from that of the legacy SSB.

[0104] The processing of base station 100 and terminal 200 may be similar to the processing shown in FIG. 9, for example.

[0105] (S101) Terminal 200 may determine sequences and resources (e.g., time resources and frequency resources) for legacy SSBs and additional SSBs based on predefined or configured information. Note that, for example, sequences common to sequences for legacy SSBs may be used for sequences for additional SSBs.

[0106] (S102) Base station 100 may transmit, for example, a legacy SSB and an additional SSB to terminal 200. For example, base station 100 may transmit the legacy SSB burst set and the additional SSB burst set using at least one of different time resources and frequency resources. Base station 100 may also set the position of at least one of the SSS and the PBCH relative to the PSS to a different position for the legacy SSB and the additional SSB. An example of signal allocation within the additional SSB in operation example 2 will be described later.

[0107] (S103) Terminal 200 may, for example, attempt to detect a PSS. For example, terminal 200 may attempt correlation detection based on a sequence (e.g., a sequence replica) related to the detection of a PSS of a legacy SSB. For example, terminal 200 may identify the timing and sequence of any PSS included in the legacy SSB burst set or the additional SSB burst set.

[0108] (S104) Terminal 200 may, for example, attempt to detect an SSS. For example, terminal 200 may attempt correlation detection by assuming (or estimating) the locations of SSB resources when the PSS detected in the process of S103 is a legacy SSB and when it is an additional SSB. In this way, terminal 200 may identify, for example, any SSS sequence included in the legacy SSB burst set or the additional SSB burst set.

[0109] For example, if an SSS is not detected, terminal 200 may return to the process of S103. For example, if an SSS is detected, terminal 200 may determine (for example, calculate) a cell ID (for example, PCI) based on the identified PSS and SSS sequences.

[0110] (S105) Terminal 200 may, for example, attempt to detect a DMRS for the PBCH. For example, terminal 200 may attempt correlation detection by assuming (or assuming) the locations of PBCH resources of both legacy SSBs and additional SSBs. In this way, terminal 200 may identify any DMRS sequence for the PBCH included in the legacy SSB burst set or the additional SSB burst set.

[0111] For example, if a DMRS is not detected, terminal 200 may return to the process of S103 or S104. For example, if a DMRS is detected, terminal 200 may calculate the SSB index (or part of the bits indicating the SSB index) based on the identified DMRS sequence for the PBCH. Furthermore, terminal 200 may estimate the channel using the detected DMRS for the PBCH.

[0112] (S106) Terminal 200 may decode the PBCH based on, for example, the PBCH resource and channel estimation value obtained in the process of S105. Terminal 200 may also obtain, for example, a half frame bit and a radio frame number (e.g., SFN) included in the PBCH. Terminal 200 may also obtain, for example, a part of the bits indicating the SSB index.

[0113] The terminal 200 may identify the time position of the received SSB based on, for example, the values ​​of the SSB index, SFN, and half frame bit.

[0114] (S107) As in operation example 1, terminal 200 may transmit a PRACH preamble in a PRACH resource associated with the SSB index obtained in the processes of S105 and S106. In this case, if terminal 200 detects SSBs at multiple timings within the SSB burst set, terminal 200 may transmit a preamble based on the SSB index of an SSB with higher reception strength or reception quality among the multiple SSBs (e.g., the SSB with the highest reception strength or reception quality).

[0115] An example of the processing of base station 100 and terminal 200 has been described above.

[0116] In this way, terminal 200 that has learned the sequence of the additional SSB in the process of S101 can receive the additional SSB in addition to the legacy SSB, thereby improving the reception quality of the SSB and expanding the receivable coverage.

[0117] On the other hand, other terminals that do not know the sequence of the additional SSB will have difficulty detecting the sequence of the additional SSB, thereby reducing the possibility of false detection of the additional SSB.

[0118] Next, an example of a signal arrangement in an additional SSB in the second operational example will be described.

[0119] (Layout example 1) FIG. 11 is a diagram showing an example of the configuration of a legacy SSB and an additional SSB in arrangement example 1. In FIG.

[0120] As shown in Figure 11, an example of the relative positions of the PSS, SSS, and PBCH within the additional SSB resource is that the SSS is placed in the 0th symbol of the additional SSB, and the PSS is placed in the 2nd symbol. Note that the first symbol of each SSB within the additional SSB (e.g., an SSB burst set) is designated as the 0th symbol.

[0121] In this way, in allocation example 1, for example, the signal allocation orders of PSS and SSS are reversed between the legacy SSB and the additional SSB. In other words, the positions where PSS and SSS are allocated are interchanged between the legacy SSB and the additional SSB.

[0122] As a result, for example, as shown in FIG. 11, since the signals allocated to the 0th symbol and the 2nd symbol are different for the legacy SSB and the additional SSB, it becomes possible to distinguish between the legacy SSB and the additional SSB. Also, for example, the sequence for the additional SSB may be set to be the same as the sequence for the legacy SSB. This makes it possible to suppress changes from standards such as Rel-15 / 16. Furthermore, the sequence common to the legacy SSB and the additional SSB enables in-phase combining (e.g., soft-combining) of the SSBs in terminal 200.

[0123] (Layout example 2) FIG. 12 is a diagram showing an example of the configuration of a legacy SSB and an additional SSB in arrangement example 2.

[0124] 12, for example, the SSS may be placed in the first symbol of the additional SSB, the PSS may be placed in the third symbol, and the PBCH may be placed in symbols 0 to 2. Note that the first symbol of each SSB in the additional SSB (for example, an SSB burst set) is designated as the 0th symbol.

[0125] In this way, in allocation example 2, for example, the signal allocation orders of PSS, SSS, and PBCH are reversed between legacy SSB and additional SSB.

[0126] As a result, as shown in FIG. 12, the signals allocated to the 0th symbol and the 2nd symbol are different for the legacy SSB and the additional SSB, making it possible to distinguish between the legacy SSB and the additional SSB. Also, for example, the sequence for the additional SSB may be set to be the same as the sequence for the legacy SSB. This makes it possible to suppress changes from standards such as Rel-15 / 16. Furthermore, the sequence common to the legacy SSB and the additional SSB enables in-phase combining (e.g., soft combining) of the SSBs in terminal 200.

[0127] Furthermore, in operation example 2, the additional SSBs are also arranged surrounded by PBCHs, just like the legacy SSBs, so interference with the SSSs can be suppressed and SSS decoding performance can be improved.

[0128] Arrangement example 1 and arrangement example 2 have been described above.

[0129] The relative positions of the signals in the additional SSB are not limited to those in Arrangement Examples 1 and 2, but may be different from the relative positions of the signals in the legacy SSB (for example, the arrangement in at least one of the time resources and the frequency resources).

[0130] This eliminates the need to generate a new sequence that differs from the sequence defined for the legacy SSB when generating an additional SSB, thereby reducing the processing load on base station 100 and terminal 200.

[0131] In addition, the sequence set for at least one of the signals included in the additional SSB is not limited to being common to the sequence of the signals included in the legacy SSB, and as in operation example 1, a sequence different from the sequence of the legacy SSB may be set.

[0132] <Example 3> In operation example 3, for example, the additional SSB may include some signals of the PSS, SSS, and PBCH. For example, in the additional SSB, of the PSS, SSS, and PBCH, the PBCH may be arranged (or transmitted), and the PSS and SSS may not be arranged (or transmitted). In other words, in operation example 3, the signal arrangement (or signal configuration) of the additional SSB may differ from the signal arrangement of the legacy SSB.

[0133] The processing of base station 100 and terminal 200 may be similar to the processing shown in FIG. 9, for example.

[0134] (S101) As in operation example 2, terminal 200 may determine sequences and resources (e.g., time resources and frequency resources) for legacy SSBs and additional SSBs based on predefined or configured information. Note that, for example, sequences common to sequences for legacy SSBs may be used for sequences for additional SSBs.

[0135] (S102) Base station 100 may transmit, for example, a legacy SSB and an additional SSB to terminal 200. For example, base station 100 may transmit the legacy SSB burst set and the additional SSB burst set in at least one of different time resources and frequency resources. Furthermore, base station 100 may transmit, for example, a PBCH in the additional SSB, but may not transmit a PSS or SSS.

[0136] Fig. 13 is a diagram showing an example of a legacy SSB and an additional SSB according to Operation Example 3. As shown in Fig. 13, a PSS, SSS, and PBCH may be transmitted in a legacy SSB (for example, an SSB burst set). On the other hand, as shown in Fig. 13, a PBCH may be transmitted in an additional SSB (for example, an SSB burst set), and a PSS and SSS may not be transmitted. In other words, the signal arrangement of the SSB (for example, whether or not a signal is arranged) may differ between the legacy SSB and the additional SSB.

[0137] (S103) Terminal 200 may, for example, attempt to detect a PSS. For example, terminal 200 may attempt correlation detection based on a sequence (e.g., a sequence replica) related to the detection of a PSS of a legacy SSB. For example, terminal 200 may identify the timing and sequence of any PSS included in the legacy SSB burst set.

[0138] (S104) Terminal 200 may, for example, attempt to detect an SSS, thereby identifying, for example, any SSS sequence included in the legacy SSB burst set.

[0139] For example, if an SSS is not detected, terminal 200 may return to the process of S103. For example, if an SSS is detected, terminal 200 may calculate a cell ID (for example, PCI) based on the identified PSS and SSS sequences.

[0140] (S105) Terminal 200 may, for example, attempt to detect a DMRS for the PBCH. For example, terminal 200 may attempt correlation detection by assuming (or assuming) the locations of PBCH resources of both legacy SSBs and additional SSBs. In this way, terminal 200 may identify any DMRS sequence for the PBCH included in the legacy SSB burst set or the additional SSB burst set.

[0141] For example, if a DMRS is not detected, terminal 200 may return to the process of S103 or S104. For example, if a DMRS is detected, terminal 200 may calculate the SSB index (or part of the bits indicating the SSB index) based on the identified DMRS sequence for the PBCH. Furthermore, terminal 200 may estimate the channel using the detected DMRS for the PBCH.

[0142] (S106) Terminal 200 may decode the PBCH based on, for example, the PBCH resources of one or both of the legacy SSB and the additional SSB and the channel estimate obtained in the process of S105. Terminal 200 may also obtain, for example, a half frame bit and a radio frame number (e.g., SFN) included in the PBCH. Terminal 200 may also obtain, for example, a part of the bits indicating the SSB index.

[0143] The terminal 200 may identify the time position of the received SSB based on, for example, the values ​​of the SSB index, SFN, and half frame bit.

[0144] (S107) As in the first operational example, terminal 200 may transmit a preamble (for example, a PRACH preamble) in the PRACH resource associated with the SSB index obtained in the processes of S105 and S106, for example.

[0145] In this way, terminal 200 that has learned the signal configuration of the additional SSB in the process of S101 can receive the additional SSB in addition to the legacy SSB, thereby improving the reception quality of the SSB (for example, PBCH) and expanding the receivable coverage.

[0146] On the other hand, other terminals that do not know the signal configuration of the additional SSB will not detect the PSS and SSS of the additional SSB, thereby reducing the possibility of false detection of the additional SSB.

[0147] Furthermore, according to the third operational example, the base station 100 and the terminal 200 do not perform the process of generating or detecting the PSS and SSS for the additional SSB, and therefore, an increase in the processing load can be suppressed.

[0148] Furthermore, according to the third operational example, for example, a PSS and an SSS are not allocated to the additional SSB, so that the resource overhead due to the additional SSB can be reduced.

[0149] In addition, the sequence set for the DMRS for PBCH included in the additional SSB is not limited to being common to the DMRS for PBCH included in the legacy SSB, and as in operation example 1, a sequence different from the sequence for the legacy SSB may be set.

[0150] <Example 4> In Operation Example 4, for example, the additional SSB may include some signals of the PSS, SSS, and PBCH. For example, in the additional SSB, of the PSS, SSS, and PBCH, the PSS may be arranged (or transmitted), and the SSS and PBCH may not be arranged (or transmitted). In other words, in Operation Example 4, the signal arrangement (or signal configuration) of the additional SSB may differ from the signal arrangement of the legacy SSB.

[0151] The processing of base station 100 and terminal 200 may be similar to the processing shown in FIG. 9, for example.

[0152] (S101) As in operation example 2, terminal 200 may determine sequences and resources (e.g., time resources and frequency resources) for legacy SSBs and additional SSBs based on predefined or configured information. Note that, for example, sequences common to sequences for legacy SSBs may be used for sequences for additional SSBs.

[0153] (S102) Base station 100 may transmit, for example, a legacy SSB and an additional SSB to terminal 200. For example, base station 100 may transmit the legacy SSB burst set and the additional SSB burst set in at least one of different time resources and frequency resources. Furthermore, base station 100 may transmit, for example, a PSS in the additional SSB, but may not transmit an SSS or a PBCH.

[0154] Fig. 14 is a diagram showing an example of a legacy SSB and an additional SSB according to operation example 4. As shown in Fig. 14, a PSS, SSS, and PBCH may be transmitted in a legacy SSB (for example, an SSB burst set). On the other hand, as shown in Fig. 14, a PSS may be transmitted in an additional SSB (for example, an SSB burst set), but an SSS and a PBCH may not be transmitted. In other words, the signal arrangement of the SSB (for example, whether or not a signal is arranged) may differ between the legacy SSB and the additional SSB.

[0155] (S103) Terminal 200 may, for example, attempt to detect a PSS. For example, terminal 200 may attempt correlation detection based on a sequence (e.g., a sequence replica) related to the detection of a PSS of a legacy SSB. For example, terminal 200 may identify the timing and sequence of any PSS included in a legacy SSB burst set or an additional SSB.

[0156] (S104) Terminal 200 may, for example, attempt to detect an SSS. For example, terminal 200 may attempt correlation detection by assuming (or estimating) the location of an SSS resource for both cases where the PSS detected in the process of S103 is a legacy SSB and an additional SSB. In this way, terminal 200 may, for example, identify any SSS sequence included in the legacy SSB burst set.

[0157] For example, if an SSS is not detected, terminal 200 may return to the process of S103. For example, if an SSS is detected, terminal 200 may calculate a cell ID (for example, PCI) based on the identified PSS and SSS sequences.

[0158] (S105) Terminal 200 may, for example, attempt to detect a DMRS for PBCH. For example, terminal 200 may attempt correlation detection by assuming (or assuming) the location of the PBCH resource of the legacy SSB. In this way, terminal 200 may identify any sequence of the DMRS for PBCH included in the legacy SSB burst set.

[0159] For example, if a DMRS is not detected, terminal 200 may return to the process of S103 or S104. For example, if a DMRS is detected, terminal 200 may calculate the SSB index (or part of the bits indicating the SSB index) based on the identified DMRS sequence for the PBCH. Furthermore, terminal 200 may estimate the channel using the detected DMRS for the PBCH.

[0160] (S106) Terminal 200 may decode the PBCH based on, for example, the PBCH resource of the legacy SSB and the channel estimate value obtained in the process of S105. Terminal 200 may also obtain, for example, a half frame bit and a radio frame number (e.g., SFN) included in the PBCH. Terminal 200 may also obtain, for example, a part of the bits indicating the SSB index.

[0161] The terminal 200 may identify the time position of the received SSB based on, for example, the values ​​of the SSB index, SFN, and half frame bit.

[0162] (S107) As in the first operational example, terminal 200 may transmit a preamble (for example, a PRACH preamble) in the PRACH resource associated with the SSB index obtained in the processes of S105 and S106, for example.

[0163] In this way, terminal 200 that has learned the signal configuration of the additional SSB in the process of S101 can receive the additional SSB in addition to the legacy SSB, thereby improving the reception quality of the SSB (for example, PSS) and expanding the receivable coverage.

[0164] On the other hand, other terminals that do not know the signal configuration of the additional SSB will not detect the SSS and PBCH of the additional SSB, thereby reducing the possibility of false detection of the additional SSB.

[0165] Furthermore, according to the fourth operational example, base station 100 and terminal 200 do not perform the process of generating or detecting the SSS and PBCH for the additional SSB, and therefore, an increase in the processing load can be suppressed.

[0166] Furthermore, according to operation example 4, for example, SSS and PBCH are not allocated to the additional SSB, so that the resource overhead due to the additional SSB can be reduced. Furthermore, terminal 200 only needs to buffer PSS for in-phase combining (e.g., soft-combining) of the legacy SSB and the additional SSB, and does not need to buffer SSS and PBCH, so that the memory size can be reduced.

[0167] Note that the sequence set in the PSS included in the additional SSB is not limited to being common to the PSS included in the legacy SSB, and similar to the first operational example, a sequence different from the sequence of the legacy SSB may be set.

[0168] Next, an example of the arrangement of PSSs in additional SSBs will be described.

[0169] (Layout example 1) FIG. 15 is a diagram showing an example of the arrangement of legacy SSBs and additional SSBs in arrangement example 1. In FIG.

[0170] As shown in FIG. 15, the PSS of the additional SSB may be arranged in a resource that is close in time to the PSS of the legacy SSB (for example, in the previous symbol).

[0171] As a result, terminal 200 can reduce the time required to complete PSS detection even when performing reception processing using a combination of legacy SSBs and additional SSBs.

[0172] Note that the time resource (e.g., symbol) in which the PSS of the additional SSB is allocated is not limited to, for example, one symbol before the symbol in which the PSS of the legacy SSB is allocated. For example, the closer the allocation symbol of the PSS of the additional SSB is to the allocation symbol of the PSS of the legacy SSB, the shorter the time until PSS detection is completed. For example, the allocation position of the PSS in the additional SSB may be a time resource within a threshold number of symbols from the time resource in which the PSS of the legacy SSB is allocated. The threshold number of symbols may be determined based on a parameter set in terminal 200, such as an allowable delay, or may be determined based on a value notified by base station 100, or may be defined in advance.

[0173] (Layout example 2) FIG. 16 is a diagram showing an example of the arrangement of legacy SSBs and additional SSBs in arrangement example 2. In FIG.

[0174] 16, the PSS of the additional SSB may be allocated to a time resource (e.g., the same symbol) as the PSS of the legacy SSB and to a frequency resource different from the PSS of the legacy SSB. In other words, the PSS of the additional SSB may be frequency-division multiplexed (FDM) in the same time resource as the PSS of the legacy SSB.

[0175] This allows terminal 200 to reduce the time required to complete PSS detection even when performing reception processing using a combination of legacy SSBs and additional SSBs. For example, in the example shown in Fig. 16, the PSSs for the legacy SSBs and additional SSBs are allocated to the same symbol, so the time required to complete PSS detection can be reduced compared to allocation example 1.

[0176] Furthermore, for example, in a symbol in which the PSS of the additional SSB and the PSS of the legacy SSB are FDM-multiplexed, non-transmission of a signal different from the PSS may be configured in frequency resources within a threshold number of subcarriers from the frequency resource in which the PSS of the additional SSB is allocated. For example, a resource (e.g., a guard resource or additional guard resource) to which a signal different from the PSS is not assigned may be configured in the frequency resource near the PSS of the additional SSB. This can mitigate interference in PSS reception.

[0177] The PSS of the additional SSB is not limited to being allocated to two frequency resources as shown in Figure 16, but may be allocated to three or more frequency resources. Furthermore, the PSS of the additional SSB is not limited to being allocated to frequency resources on both ends of the PSS of the legacy SSB as shown in Figure 16, but may be allocated to one frequency resource of the PSS of the legacy SSB.

[0178] The above describes an example of PSS placement in an additional SSB.

[0179] It is also possible to combine Arrangement Example 1 and Arrangement Example 2. For example, the PSS in the additional SSB may be arranged in resources that are different in both time and frequency from the PSS of the legacy SSB.

[0180] Furthermore, in operation example 4, the allocation of PSS in the additional SSB has been described, but the signal transmitted in the additional SSB is not limited to PSS, and may be at least one of PSS, SSS, PBCH, and DMRS for PBCH. For example, in the additional SSB, SSS may be transmitted, but PSS and PBCH may not be transmitted. The above-described PSS allocation may be applied to the allocation of SSS in the additional SSB. This allows the reception coverage of the SSS to be expanded.

[0181] <Example 5> An example of allocation resources for additional SSBs will be described in Operation Example 5. Note that Operation Example 5 may be combined with any of Operation Examples 1 to 4, for example.

[0182] [Variations in placement of additional SSB] Below, we will explain variations in how to arrange additional SSBs.

[0183] (Variation 1) The additional SSB may be arranged, for example, in a time resource different from the time resource in which the legacy SSB is arranged.

[0184] With this arrangement, base station 100 transmits the legacy SSB and the additional SSB using different time resources, so that it can set higher transmission power to be allocated to each SSB in each time resource compared to, for example, a method in which the legacy SSB and the additional SSB are FDM-multiplexed, thereby improving the reception quality of each SSB at terminal 200.

[0185] (Variation 2) The additional SSBs may be arranged, for example, in frequency resources different from the frequency resources in which the legacy SSBs are arranged.

[0186] For example, legacy SSBs in a primary cell (Pcell) may be transmitted on subcarriers indicated by a defined synchronization raster (SS raster), while additional SSBs may be transmitted on subcarriers different from those indicated by the SS raster. Alternatively, a raster for additional SSBs may be defined, and the additional SSBs may be transmitted on subcarriers indicated by the raster for additional SSBs.

[0187] This reduces the possibility that a terminal other than terminal 200 (for example, a Rel-15 / 16 terminal) will erroneously detect an additional SSB, for example.

[0188] (Variation 3) The additional SSBs may be time-division multiplexed (TDM) in a frequency resource that is common (e.g., the same) as the frequency resource in which the legacy SSBs are allocated. This allocation eliminates the need for terminal 200 to monitor multiple frequency bands when detecting the legacy SSBs and the additional SSBs, thereby reducing the processing load.

[0189] Furthermore, the additional SSB may be frequency-multiplexed in a time resource common (e.g., the same) to the time resource in which the legacy SSB is arranged. This arrangement allows terminal 200 to reduce the time required to detect the legacy SSB and the additional SSB, for example.

[0190] Variations 1 to 3 have been described above.

[0191] It is also possible to combine, for example, Variation 1 and Variation 2. For example, the additional SSB may be allocated to time resources and frequency resources that are different from both the time resources and frequency resources in which the legacy SSB is allocated.

[0192] [Multiplexing with Type 0 PDCCH] The additional SSB may be, for example, TDM or FDMed with either or both of the resources of a Type 0 PDCCH (also called CORESET 0 (CONTROL REsource SET 0) or Search Space 0) or the resources of a PDSCH allocated by the Type 0 PDCCH.

[0193] For example, when base station 100 sets the value of "SS / PBCH block and CORESET multiplexing pattern" to 2 or 3, i.e., when the frequency resources of the Type-0 PDCCH or PDSCH are different from the frequency resources of the legacy SSBs, the additional SSBs may be TDM'd in the frequency resources common to the Type-0 PDCCH or PDSCH. This allows terminal 200 to receive the additional SSBs, Type-0 PDCCH, and PDSCH within a relatively narrow frequency band.

[0194] Fig. 17 shows an example in which the value of the SS / PBCH block and CORESET multiplexing pattern is set to 2. In the example shown in Fig. 17, the additional SSB is TDM-modulated in the frequency resources common to the Type 0 PDCCH and the PDSCH allocated by the Type 0 PDCCH.

[0195] Furthermore, for example, when base station 100 sets the value of SS / PBCH block and CORESET multiplexing pattern to 1, that is, when the time resource of the Type-0 PDCCH or PDSCH is different from the time resource of the legacy SSB, the additional SSB may be FDM-modulated in the time resource common to the Type-0 PDCCH or PDSCH. This allows terminal 200 to receive the additional SSB, Type-0 PDCCH, and PDSCH within a relatively short time.

[0196] Fig. 18 shows an example in which the values ​​of the SS / PBCH block and CORESET multiplexing pattern are set to 1. In the example shown in Fig. 18, the additional SSB is FDM-modulated in the time resource shared with the PDSCH allocated by the Type 0 PDCCH, but this is not limiting, and for example, the additional SSB may be FDM-modulated in the time resource shared with the Type 0 PDCCH.

[0197] In addition, the multiplexing method for the additional SSB and the Type 0 PDCCH may be determined and applied regardless of the values ​​of the SS / PBCH block and CORESET multiplexing pattern.

[0198] The values ​​of the SS / PBCH block and CORESET multiplexing pattern may be specified in association with, for example, values ​​notified as controlResourceSetZero, searchSpaceZero, or pdcch-ConfigSIB1, which are upper layer parameters included in a Master Information Block (MIB) transmitted by the PBCH. Furthermore, the above-mentioned PDSCH may transmit, for example, Remaining System Information (RMSI) or System Information Block Type 1 (SIB1).

[0199] [Identifying and notifying how additional SSBs will be deployed] In the processing of S101 in each of the above-described operation examples, the method by which terminal 200 identifies information regarding legacy SSBs and additional SSBs (e.g., information regarding sequences and resource allocation methods) is not limited to, for example, pre-defined or pre-configured information.

[0200] For example, the method by which terminal 200 identifies information regarding legacy SSBs and additional SSBs may be based on an explicit or implicit instruction (e.g., an indication or configuration) from base station 100. Note that the instruction may be notified to terminal 200 by at least one of DCI and higher layer signaling, for example.

[0201] Furthermore, the information regarding the resource (e.g., at least one of time resource and frequency resource) where the additional SSB is located may be, for example, information indicating an absolute position or information indicating a relative position (e.g., offset) from the legacy SSB. For example, the time offset may be expressed in units of time resources such as frames, subframes, slots, or symbols. Furthermore, the frequency offset may be expressed in units of frequency resources such as resource blocks or subcarriers.

[0202] Furthermore, for example, when a legacy SSB burst set is allocated to one of the first half of a frame (e.g., the first half frame) and the second half of a frame (e.g., the second half frame) (but not to the other), an additional SSB burst set may be allocated to the other. In this case, the resource allocation of SSBs within the half frame may be common (e.g., the same) for the legacy SSB and the additional SSB.

[0203] 19 is a diagram showing an example of the allocation of legacy SSBs and additional SSBs. In FIG. 19, for example, legacy SSBs are allocated in the first half frame, and additional SSBs are allocated in the second half frame. Also, for example, as shown in FIG. 19, if legacy SSBs are allocated in the 4th, 8th, 16th, and 20th symbols of one half frame, terminal 200 may determine that additional SSBs are allocated in the 4th, 8th, 16th, and 20th symbols of the other half frame.

[0204] This method allows terminal 200 to identify the location of additional SSBs based on, for example, information about the location of legacy SSBs, thereby reducing notifications about additional SSBs.

[0205] [Relationship with SSB burst set] The number of SSBs (or SSB candidates) transmitted in the legacy SSB burst set and the number of SSBs transmitted in the additional SSB burst set may be the same or different.

[0206] FIG. 20 is a diagram showing an example of a legacy SSB burst set and an additional SSB burst set. In FIG. 20, for example, the number of SSBs in the legacy SSB burst set is four, and the number of SSBs in the additional SSB burst set is two. In the example of FIG. 20, for example, the resource overhead of the additional SSBs can be reduced. Furthermore, since the processing related to the additional SSBs can be reduced, power consumption in base station 100 and terminal 200 can be reduced.

[0207] The number of SSBs in the legacy SSB burst set and the additional SSB burst set is not limited to the example shown in FIG. 20, and may be other numbers.

[0208] Furthermore, the number of SSB burst sets transmitted as additional SSBs may be the same as or different from the number of legacy SSB burst sets. For example, the number of SSB burst sets transmitted as additional SSBs may be an integer multiple of the number of legacy SSB burst sets.

[0209] Fig. 21 shows an example of a legacy SSB burst set and an additional SSB burst set. In Fig. 21, for example, the number of SSB burst sets transmitted as additional SSBs (e.g., three sets) is set to three times the number of legacy SSB burst sets (e.g., one set). Note that the number of SSB burst sets set as additional SSBs is not limited to the example shown in Fig. 21, and may be other numbers.

[0210] For example, the more SSBs transmitted as additional SSBs, the greater the SSB reception coverage can be extended.

[0211] Furthermore, when multiple additional SSB burst sets are transmitted, the number of SSBs in each additional SSB burst set may be different. For example, the number of SSBs in one additional SSB burst set may be less than the number of SSBs in another additional SSB burst set. This reduces the resource overhead of the additional SSBs.

[0212] Furthermore, when multiple additional SSB burst sets are transmitted, at least one of the sequences and signal constellations set for each additional SSB burst set may be common, for example. This makes it possible to prevent the complexity of the additional SSB decoding process in terminal 200.

[0213] When multiple additional SSB burst sets are transmitted, at least one of the sequences and signal constellations set for each additional SSB burst set may be different.

[0214] [Unlicensed band] Each of the above-described operation examples may be applied to, for example, communication in an unlicensed band (also called, for example, an unlicensed spectrum or a shared spectrum).

[0215] At this time, among the SSB candidates (for example, SSB candidates), the N SSB QCL Legacy SSBs are transmitted in N SSB candidates, SSB QCL Additional SSBs may be transmitted in SSB candidates after N SSBs. SSB QCL may be a value notified to terminal 200 by a higher layer or DCI.

[0216] FIG. 22 shows an example of N SSBQCL 22 is a diagram showing an example of SSB configuration when SSB candidate index=4 and the number of SSB candidates is 10 (for example, SSB candidate index 0 to 9). In FIG. 22, for example, after completion of LBT, legacy SSBs are transmitted in four SSB candidates with SSB candidate index=1 to 4, and additional SSBs are transmitted in the other five SSB candidates with SSB candidate index=5 to 9.

[0217] An example of the operation of base station 100 and terminal 200 has been described above.

[0218] Note that parameters such as the sequence length and type of DMRS for PSS, SSS and PBCH, signal arrangement in SSB, and configuration of each SSB burst set (e.g., the number of SSBs in a burst set or the number of burst sets) are not limited to the above examples.

[0219] As described above, in this embodiment, terminal 200 receives, for example, legacy SSBs and additional SSBs that differ from the legacy SSBs in at least one of the sequence and signal arrangement, and performs a cell search based on the legacy SSBs and the additional SSBs.

[0220] As a result, for example, terminal 200 to which CE or RedCap is applied can expand the coverage over which SSB can be received. Therefore, according to this embodiment, it is possible to improve the reception quality of SSB in terminal 200. Furthermore, for example, in a Rel-15 / 16 terminal or other terminals that are Rel-17 or later and do not apply the technology established in the CE or RedCap specifications, it is possible to suppress false detection of additional SSBs and suppress synchronization failures.

[0221] The embodiments of the present disclosure have been described above.

[0222] [Other embodiments] (Additional SSB series) In the additional SSB, for example, a sequence different from the sequence of the legacy SSB may be applied to the PSS, and a sequence common to the sequence of the legacy SSB may be applied to other signals (for example, SSS and DMRS for PBCH). This allows terminal 200 to, for example, attempt detection assuming both the legacy SSB and the additional SSB when detecting (or searching for) the PSS, and to attempt detection assuming the legacy SSB when detecting other signals (for example, SSS and DMRS for PBCH), thereby reducing the processing load on terminal 200.

[0223] Furthermore, for additional SSBs, sequences different from those of legacy SSBs may be applied to PSS and SSS, and sequences common to those of legacy SSBs may be applied to other signals (e.g., DMRS for PBCH). This allows terminal 200 to, for example, attempt detection assuming both legacy SSBs and additional SSBs when detecting (or searching for) PSS and SSS, and to attempt detection assuming legacy SSBs when detecting other signals (e.g., DMRS for PBCH), thereby reducing the processing load on terminal 200.

[0224] Furthermore, in the additional SSB, sequences different from the sequences of legacy SSBs may be applied to the PSS, SSS, and DMRS for PBCH, which reduces the possibility that terminals other than terminal 200 (e.g., Rel-15 / 16 terminals, or terminals in Rel-17 or later that do not apply technology established in the CE or RedCap specifications) will erroneously detect the additional SSB.

[0225] Note that a sequence different from that of the legacy SSB may be applied to any one or a combination of multiple PSSs, SSSs, and DMRSs for PBCH included in the additional SSBs.

[0226] (Transmission power) In the above-described embodiments, the additional SSBs may be transmitted at a higher power than the legacy SSBs, thereby extending the coverage over which the additional SSBs can be received.

[0227] (Information carried by PBCH) In the above-described embodiment, the information carried by the PBCH of the additional SSB may be common (for example, identical) to the information carried by the PBCH of the legacy SSB. This enables terminal 200 to perform combined reception of the PBCH of the legacy SSB and the PBCH of the additional SSB, for example, thereby improving reception accuracy.

[0228] Alternatively, the information carried by the PBCH of the additional SSB may be different from the information carried by the PBCH of the legacy SSB. For example, the PBCH of the additional SSB may explicitly or implicitly notify terminal 200 that the SSB corresponding to the PBCH is an "additional SSB." This can reduce the possibility that terminals other than terminal 200 will erroneously detect the additional SSB, for example.

[0229] (Reception process by terminal 200) Terminal 200 may, for example, receive and decode the legacy SSB and the additional SSB separately. In other words, terminal 200 may, for example, receive and decode the legacy SSB and the additional SSB without in-phase combining (for example, soft-combining). This allows terminal 200 to receive each SSB even if the legacy SSB and the additional SSB have different sequence or signal configurations (for example, signal sequences).

[0230] Terminal 200 may also perform reception and decoding processing based on, for example, a combination of legacy SSBs and additional SSBs. For example, terminal 200 may receive legacy SSBs and additional SSBs by soft-combining, or may detect a single sequence that combines a legacy SSB sequence and an additional SSB sequence. This can improve the reception accuracy of SSBs in terminal 200. Regarding soft-combining, terminal 200 may also combine SSBs with the same SSB index, for example.

[0231] Furthermore, terminal 200 may receive additional SSBs and not receive legacy SSBs, for example. This allows power consumption for reception processing in terminal 200 to be reduced.

[0232] (Radio Resource Management (RRM) and Radio Link Monitoring (RLM) measurements) For example, terminal 200 and other terminals different from terminal 200 may perform RRM measurements and RLM measurements using legacy SSBs or additional SSBs. At this time, information about additional SSBs transmitted in the current cell or nearby cells may be reported to terminal 200. This enables RRM or RLM measurements using the additional SSBs, thereby improving measurement accuracy.

[0233] (Device type, identification) The terminal 200 may be, for example, a “RedCap terminal” or a “CE terminal.” Furthermore, the terminal 200 may be, for example, a terminal having at least one of the following characteristics (in other words, properties, attributes, or capabilities): (1) A terminal that notifies (for example, reports) the base station 100 that it is a "terminal subject to coverage extension," a "terminal that receives a repeatedly transmitted signal," a "RedCap terminal," or a "CE terminal." (2) A terminal that meets at least one of the following capabilities, or a terminal that reports at least one of the following capabilities to the base station 100: -A terminal with the number of implemented receive antennas below a threshold (for example, threshold = 1). A terminal whose number of supportable receive antenna ports is equal to or less than a threshold (for example, threshold = 2). A terminal whose maximum number of Multiple-Input Multiple-Output (MIMO) layers (or ranks) that can be supported is less than or equal to a threshold (e.g., threshold = 2). - A terminal that can receive SSB in a frequency band above a threshold (e.g., Frequency Range 2 (FR2)). -Devices with processing times exceeding the threshold. -A terminal whose available transport block size (TBS) is below a threshold. -A terminal with the number of available MIMO transmission layers below a threshold. -Terminals whose available modulation order is below a threshold. -A terminal whose number of available Hybrid Automatic Repeat request (HARQ) processes is below a threshold. -Devices that support Rel-17 and later.

[0234] (RRC state) In the above-described embodiment, the mode set in terminal 200 (e.g., the state of terminal 200) may be, for example, RRC_IDLE mode, RRC_INACTIVE mode, or RRC_CONNECTED mode. In other words, the mode may be set before or after RRC configuration in terminal 200.

[0235] (numerology) The bandwidth of the SSB may vary depending on the set numerology or subcarrier spacing.

[0236] (control signal) In the above embodiment, the control signal may be a PDCCH that transmits DCI in the physical layer, or may be MAC or RRC in a higher layer.

[0237] (base station) In the above-described embodiments, the base station may be a TRP (Transmission Reception Point), a cluster head, an access point, an RRH (Remote Radio Head), an eNodeB (eNB), a gNodeB (gNB), a BS (Base Station), a BTS (Base Transceiver Station), a parent device, a gateway, etc. In addition, in sidelink communication, a terminal may act in place of a base station.

[0238] (uplink / downlink) In the above embodiment, a synchronization signal or PBCH, which is a downlink signal, has been described as an example, but the present invention is not limited to these and can also be applied to an uplink signal, for example, a PUSCH or a PRACH.

[0239] (broadcast channel / data channel / control channel) In the above embodiment, the PBCH used for cell search has been described as an example, but the present invention is not limited to this and may be applied to the PDSCH used for data transmission and the PDCCH used for transmission of control information.

[0240] (reference signal) In the above embodiments, the reference signal is a signal known to both the base station and the terminal, and may also be called an RS (Reference Signal), a reference signal, or a pilot signal. The reference signal may be a DMRS, a CSI-RS (Channel State Information - Reference Signal), a TRS (Tracking Reference Signal), a PTRS (Phase Tracking Reference Signal), an SRS (Sounding Reference Signal), or a CRS (Cell-specific Reference Signal).

[0241] (time interval) In the above embodiments, 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 OFDM (Orthogonal Frequency Division Multiplexing) symbol, or an SC-FDMA (Single Carrier-Frequency Division Multiplexing) 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 embodiments, and may be another number of symbols.

[0242] (Applicable to side links) The above-described embodiment may also be applied to communication using a sidelink used for V2X (Vehicle to Everything) or terminal-to-terminal communication. In this case, the PDCCH may be a PSCCH (Physical Sidelink Control Channel), the PUSCH / PDSCH may be a PSSCH (Physical Sidelink Shared Channel), and the PUCCH may be a PSFCH (Physical Sidelink Feedback Channel).

[0243] <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).

[0244] For example, the system architecture assumes a Next Generation - Radio Access Network (NG-RAN) with gNBs as a whole. 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 23 (see, for example, 3GPP TS 38.300 v15.6.0, section 4).

[0245] 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.

[0246] For example, the Medium-Access-Control layer handles logical channel multiplexing and scheduling and scheduling-related functions, including handling various numerologies.

[0247] 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.

[0248] 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 that are approximately three times higher than those offered by IMT-Advanced. On the other hand, URLLC imposes stricter requirements for ultra-low latency (0.5 ms user-plane latency for UL and DL, respectively) and high reliability (1-10-5 within 1 ms). Finally, mMTC preferably requires high connection density (1,000,000 devices / km in urban environments). 2 ), wide coverage in adverse environments, and extremely long battery life (15 years) for low-cost devices may be desired.

[0249] 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.

[0250] 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).

[0251] <Functional separation between NG-RAN and 5GC in 5G NR> Figure 24 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.

[0252] 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.

[0253] 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; - 3GPP Core Network (CN) inter-node signaling for mobility between access networks; - Reachability to idle mode UEs (including control and execution of paging retransmissions); - Managing the registration area; - Support for intra-system and inter-system mobility; - Access authentication; - Access authorization, including checking roaming privileges; - Mobility management control (subscription and policy); - Network slicing support; - Selection of Session Management Function (SMF).

[0254] 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 the QoS flow of SDF); - Downlink packet buffering and triggering function for downlink data notification.

[0255] Finally, the Session Management Function (SMF) hosts the following main functions: - Session management; - IP address allocation and management for the UE; - Selection and control of the UPF; - Traffic steering setting function in the User Plane Function (UPF) for routing traffic to the appropriate destination; - Enforcement of control part policies and QoS; - Notification of downlink data.

[0256] <Procedures for RRC connection setup and reconfiguration> Figure 25 shows some of the interactions between the UE, gNB, and AMF (5GC entity) in the NAS part when the UE transitions from RRC_IDLE to RRC_CONNECTED (see TS 38.300 v15.6.0).

[0257] 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 to the gNB. The gNB then sends an RRCReconfiguration message to the UE, and upon receiving an RRCReconfigurationComplete message 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.

[0258] 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.

[0259] <IMT usage scenarios from 2020 onwards> Figure 26 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 26 shows some example use scenarios envisioned for IMT beyond 2020 (see, for example, ITU-R M.2083 Figure 2).

[0260] 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.

[0261] 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.

[0262] 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.

[0263] 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.

[0264] 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.

[0265] 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)).

[0266] 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. In addition, the enhancement of UCI (Uplink Control Information) is related to the enhancement of enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback. Also, there may be enhancements to the PUSCH related to mini-slot level hopping, and enhancements to retransmission / repetition. The term "mini-slot" refers to a Transmission Time Interval (TTI) that contains fewer symbols than a slot (a slot has 14 symbols).

[0267] <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 flow) and QoS flows that do not require a guaranteed flow bit rate (non-GBR QoS flow). 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.

[0268] 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 25. 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 and DL packets with QoS flows, while AS-level mapping rules in the UE and the NG-RAN associate UL and DL QoS flows with DRBs.

[0269] Figure 27 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 26) 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.

[0270] Figure 27 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.

[0271] 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.

[0272] The present disclosure can be realized by software, hardware, or software in conjunction with hardware. Each functional block described in the above embodiments may be partially or entirely realized as an LSI, which is an integrated circuit. Each process described in the above embodiments may be partially or entirely controlled by a single LSI or a combination of LSIs. An LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. An LSI may have data inputs and outputs. Depending on the level of integration, an LSI may be referred to as an IC, system LSI, super LSI, or ultra LSI. The integration method is not limited to LSIs; it may also be realized by dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, a field programmable gate array (FPGA), which can be programmed after LSI fabrication, or a reconfigurable processor, which allows the connections and settings of circuit cells within an LSI to be reconfigured, may also be used. The present disclosure may be realized as digital or analog processing. 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.

[0273] 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.

[0274] 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.

[0275] Communications include data communications via cellular systems, wireless LAN systems, communications satellite systems, etc., as well as data communications via combinations of these.

[0276] 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.

[0277] 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.

[0278] A terminal according to one embodiment of the present disclosure includes a receiving circuit that receives a first synchronization signal block and a second synchronization signal block that differs from the first synchronization signal block in at least one of a sequence and a signal arrangement, and a control circuit that performs a cell search based on the first synchronization signal block and the second synchronization signal block.

[0279] In one embodiment of the present disclosure, the sequences of at least one signal among the first synchronization signal, the second synchronization signal, and the reference signal placed in each synchronization signal block are different between the first synchronization signal block and the second synchronization signal block.

[0280] In one embodiment of the present disclosure, the sequence for one of the first synchronization signal block and the second synchronization signal block is a sequence obtained by rearranging elements of the sequence for the other of the first synchronization signal block and the second synchronization signal block.

[0281] In one embodiment of the present disclosure, the sequence for one of the two is a sequence in which the order of elements of the sequence for the other of the two is reversed.

[0282] In one embodiment of the present disclosure, the sequence for one of the two is a sequence obtained by cyclically rotating elements of the sequence for the other of the two.

[0283] In one embodiment of the present disclosure, the sequence for one of the signals is a sequence in which elements of the sequence for the other signal are interleaved.

[0284] In one embodiment of the present disclosure, the signal arrangement orders of the first synchronization signal, the second synchronization signal, and the broadcast signal are different between the first synchronization signal block and the second synchronization signal block.

[0285] In one embodiment of the present disclosure, the signal arrangement orders of the first synchronization signal and the second synchronization signal are reversed between the first synchronization signal block and the second synchronization signal block.

[0286] In one embodiment of the present disclosure, the signal arrangement orders of the first synchronization signal, the second synchronization signal, and the broadcast signal are reversed between the first synchronization signal block and the second synchronization signal block.

[0287] In one embodiment of the present disclosure, the first synchronization signal block includes a first synchronization signal, a second synchronization signal, and a broadcast signal, and the second synchronization signal block includes some of the first synchronization signal, the second synchronization signal, and the broadcast signal.

[0288] In one embodiment of the present disclosure, the second synchronization signal block includes a broadcast signal and does not include the first synchronization signal and the second synchronization signal.

[0289] In one embodiment of the present disclosure, the secondary synchronization signal block includes the primary synchronization signal, but does not include the secondary synchronization signal and the broadcast signal.

[0290] In one embodiment of the present disclosure, the arrangement position of the first synchronization signal in the second synchronization signal block is a time resource within a threshold number of symbols from the time resource in which the first synchronization signal is arranged in the first synchronization signal block.

[0291] In one embodiment of the present disclosure, the placement position of the first synchronization signal in the second synchronization signal block is a time resource common to the first synchronization signal in the first synchronization signal block and a frequency resource different from the first synchronization signal in the first synchronization signal block.

[0292] In one embodiment of the present disclosure, non-transmission of a signal different from the first synchronization signal is set in frequency resources within a threshold number of subcarriers from the frequency resource in which the first synchronization signal of the second synchronization signal block is allocated.

[0293] A base station according to one embodiment of the present disclosure includes a control circuit that generates a first synchronization signal block and a second synchronization signal block that differs from the first synchronization signal block in at least one of a sequence and a signal arrangement, and a transmission circuit that transmits the first synchronization signal block and the second synchronization signal block.

[0294] In a communication method according to one embodiment of the present disclosure, a terminal receives a first synchronization signal block and a second synchronization signal block that differs from the first synchronization signal block in at least one of a sequence and a signal arrangement, and performs a cell search based on the first synchronization signal block and the second synchronization signal block.

[0295] In a communication method according to one embodiment of the present disclosure, a base station generates a first synchronization signal block and a second synchronization signal block that differs from the first synchronization signal block in at least one of a sequence and a signal arrangement, and transmits the first synchronization signal block and the second synchronization signal block.

[0296] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2020-133006, filed on August 5, 2020, are incorporated herein by reference in their entirety. [Industrial Applicability]

[0297] One embodiment of the present disclosure is useful in wireless communication systems. [Explanation of symbols]

[0298] 100 base stations 101,208 Control unit 102 signal generation unit 103,209 Encoding and modulation section 104 Signal arrangement section 105,210 Transmitter 106,201 antennas 107,202 Receiver 108,206 Demodulation and Decoding Unit 200 devices 203 Signal separation section 204 Signal detection unit 205 Channel Estimation Unit 207 Notification information receiving unit

Claims

1. a receiving circuit for receiving a second synchronization signal block allocated to a resource different from that of the first synchronization signal block; a control circuit for identifying resources of the second synchronization signal block; the time resources in the second synchronization signal block are indicated by an offset relative to the time resources in the first synchronization signal block; the number of the secondary synchronization signal blocks is less than the number of the primary synchronization signal blocks in the time domain; Terminal.

2. The frequency resource of the second synchronization signal block is different from the frequency resource of the first synchronization signal block. The terminal according to claim 1 .

3. The information regarding the resource of the first synchronization signal block and the information regarding the resource of the second synchronization signal block are notified by an upper layer. The terminal according to claim 1 .

4. the first synchronization signal block and the second synchronization signal block are frequency-multiplexed in the same time resource; The terminal according to claim 1 .

5. The second synchronization signal block is frequency-multiplexed with a Physical Downlink Control Channel (PDCCH); The terminal according to claim 1 .

6. The first synchronization signal block is used by a non-RedCap terminal, and the second synchronization signal block is used by a RedCap terminal. The terminal according to claim 1 .

7. receiving a second synchronization signal block arranged in a resource different from that of the first synchronization signal block; Identifying resources for the secondary synchronization signal block; the time resources in the second synchronization signal block are indicated by an offset relative to the time resources in the first synchronization signal block; the number of the secondary synchronization signal blocks is less than the number of the primary synchronization signal blocks in the time domain; Communication method.

8. The frequency resource of the second synchronization signal block is different from the frequency resource of the first synchronization signal block. The communication method according to claim 7.

9. The information regarding the resource of the first synchronization signal block and the information regarding the resource of the second synchronization signal block are notified by an upper layer. The communication method according to claim 7.

10. the first synchronization signal block and the second synchronization signal block are frequency-multiplexed in the same time resource; The communication method according to claim 7.

11. The second synchronization signal block is frequency-multiplexed with a Physical Downlink Control Channel (PDCCH); The communication method according to claim 7.

12. The first synchronization signal block is used by a non-RedCap terminal, and the second synchronization signal block is used by a RedCap terminal. The communication method according to claim 7.

13. receiving a second synchronization signal block arranged in a resource different from that of the first synchronization signal block; a process of identifying resources for the secondary synchronization signal block; the time resources in the second synchronization signal block are indicated by an offset relative to the time resources in the first synchronization signal block; the number of the secondary synchronization signal blocks is less than the number of the primary synchronization signal blocks in the time domain; Integrated circuit.

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