Base stations, communication methods, and integrated circuits

Abstract

To improve the reception quality of synchronization signals at the terminal. [Solution] The base station comprises a control circuit that identifies resources different from those of the first synchronization signal block as resources for the second synchronization signal block, and a transmission circuit that transmits the second synchronization signal block located in the resources of the second synchronization signal block, wherein 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, and the number of second synchronization signal blocks is less than the number of first synchronization signal blocks in the time domain.

Description

[Technical Field]

[0001] This disclosure relates to terminals, base stations, and communication methods. [Background technology]

[0002] A communication system called the fifth-generation mobile communication system (5G) is being considered. The 3rd Generation Partnership Project (3GPP), an international standardization organization, is considering the advancement of 5G communication systems from two perspectives: the advancement of the LTE / LTE-Advanced system and the development of a new method called New Radio Access Technology (also called New RAT or NR) (see, for example, Non-Patent Document 1), which is not necessarily backward compatible with the LTE / LTE-Advanced system. [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 [Overview of the project]

[0004] However, there is room for consideration regarding methods to improve the reception quality of synchronization signals at the terminal.

[0005] Non-limiting embodiments of this disclosure contribute to the provision of terminals, base stations, and communication methods that can improve the reception quality of synchronization signals at terminals.

[0006] A terminal according to one embodiment of the present disclosure comprises a receiving circuit that receives a first synchronization signal block and a second synchronization signal block in which at least one of the sequence and signal arrangement differs from that of the first synchronization signal block, 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 embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or recording media, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media.

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

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

[0010] [Figure 1] This diagram shows an example configuration of a Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) Block (SSB). [Figure 2] Figure showing an example of beam sweeping. [Figure 3] Figure showing an example of beam sweeping. [Figure 4] Figure showing an example of legacy SSB and additional SSB. [Figure 5]Block diagram showing a partial configuration example of a base station [Figure 6] Block diagram showing a partial configuration example of a terminal [Figure 7] Block diagram showing a configuration example of a base station [Figure 8] Block diagram showing a configuration example of a terminal [Figure 9] Flowchart showing operation examples of a base station and a terminal [Figure 10] Diagram showing an example of a legacy SSB and an additional SSB according to operation example 1 [Figure 11] Diagram showing an example of a legacy SSB and an additional SSB according to operation example 2 [Figure 12] Diagram showing an example of a legacy SSB and an additional SSB according to operation example 2 [Figure 13] Diagram showing an example of a legacy SSB and an additional SSB according to operation example 3 [Figure 14] Diagram showing an example of a legacy SSB and an additional SSB according to operation example 4 [Figure 15] Diagram showing an example of a legacy SSB and an additional SSB according to operation example 4 [Figure 16] Diagram showing an example of a legacy SSB and an additional SSB according to operation example 4 [Figure 17] Diagram showing an example of multiplexing between an additional SSB and a type 0 Physical Downlink Control Channel (PDCCH) [Figure 18] Diagram showing an example of multiplexing between an additional SSB and a type 0 PDCCH [Figure 19] Diagram showing a setting example of a legacy SSB and an additional SSB [Figure 20] Diagram showing a setting example of a legacy SSB and an additional SSB [Figure 21] Diagram showing a setting example of a legacy SSB and an additional SSB [Figure 22] Diagram showing a setting example of a legacy SSB and an additional SSB in an unlicensed band [Figure 23] Diagram of an exemplary architecture of a 3GPP NR system [Figure 24] Schematic diagram showing the functional separation between NG-RAN and 5GC. [Figure 25] Sequence diagram of the setup / reconfiguration procedure for Radio Resource Control (RRC) connection. [Figure 26] This schematic diagram illustrates usage scenarios for high-capacity, high-speed communication (eMBB: enhanced Mobile Broadband), massive machine type communications (mMTC: massive machine type communications), and highly reliable, ultra-low-latency communications (URLLC: Ultra Reliable and Low Latency Communications). [Figure 27] Block diagram illustrating an exemplary 5G system architecture for a non-roaming scenario. [Modes for carrying out the invention]

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

[0012] In the following explanation, for example, a wireless frame, slot, and symbol are units of physical resources in the time domain. For example, the length of one frame may be 10 milliseconds. For example, one frame may consist of multiple slots (e.g., 10, 20, or other values). Also, for example, the number of slots that make up one frame may vary depending on the slot length. Also, one slot may consist of multiple symbols (e.g., 14 or 12). For example, one symbol is the smallest unit of physical resources 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, 15kHz, 30kHz, 60kHz, 120kHz, 240kHz, 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 (for example, also called NR terminals) (or CE: Coverage Enhancement) with a wider communication area (or coverage) compared to terminals (for example, mobile stations or also called User Equipment (UE)) corresponding to Release 15 or 16 (hereinafter referred to as Rel-15 / 16NR) (see, for example, Non-Patent Document 2).

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

[0016] [Cell search by device] Terminals that are not connected to a cell (for example, terminals in RRC_IDLE mode) may discover a cell using, for example, a synchronization signal block (SSB: Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) Block) transmitted from a base station. For example, the procedure for discovering a cell is called a cell search.

[0017] During cell search, the terminal may perform, for example, symbol synchronization, identification of cell IDs (e.g., PCI: Physical-layer Cell Identities), identification of slot numbers, and identification of frame numbers.

[0018] Figure 1 shows an example of an SSB configuration. As shown in Figure 1, an SSB may be a set of signals (or signal block) including a primary synchronization signal (PSS: Primary SS, or first synchronization signal), a secondary synchronization signal (SSS: Secondary SS, or second synchronization signal), a broadcast channel (PBCH, or broadcast signal), and a reference signal for the PBCH (e.g., DMRS: Demodulation Reference Signal). For example, as shown in Figure 1, the PSS may be placed at the beginning of the SSB (e.g., the 0th symbol), the SSS may be placed at the 2nd symbol of the SSB, and the PBCH may be placed at the 1st to 3rd symbols of the SSB. Also, the DMRS for the PBCH may be placed, for example, within the PBCH area of ​​the 1st to 3rd symbols of the SSB.

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

[0020] The following describes an example of cell search processing using SSB on a terminal.

[0021] (1) PSS detection The terminal may, for example, attempt to detect the PSS. For example, the PSS may be transmitted to the terminal using one of three known sequences (e.g., length 127). The terminal does not know, for example, when the PSS is transmitted. The terminal may, for example, calculate the correlation between the received signal at a certain time resource (e.g., a symbol) and a replica of a known sequence for the PSS. The terminal may, for example, determine that symbol synchronization has been achieved if it detects a symbol with a high correlation value with any of the replicas (e.g., a symbol with a correlation value above a threshold). The terminal may also, for example, use the sequence of the PSS at the time of symbol synchronization to determine (e.g., calculate) the cell ID (e.g., PCI) described later, a parameter (e.g., N ID (2) You may specify the value of ).

[0022] (2) SSS detection The terminal may, for example, attempt to detect an SSS. For example, the SSS may be transmitted using one of 336 known sequences (e.g., length 127) at the symbol two positions after the symbol where the PSS detected by the terminal is placed (e.g., the 0th symbol of the SSB) (e.g., the 2nd symbol of the SSB). The terminal may, for example, calculate the correlation between the received signal at the symbol where the SSS may be transmitted and the known sequence replica for the SSS. The terminal may, for example, determine a sequence with a high correlation value (e.g., a sequence with a correlation value above a threshold) to be an SSS sequence. The terminal may also, for example, determine a parameter (N) based on the identified SSS sequence. ID(1) You may specify the value of ).

[0023] The terminal may then identify the cell ID (e.g., PCI) based on the identified PSS and SSS series. The terminal may, for example, identify PCI as "3N ID(1) + N ID(2) It may be calculated by "[ ]".

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

[0025] The terminal may, for example, calculate the correlation between the received DMRS signal in a symbol that can transmit PBCH DMRS and a replica that differs depending on the slot number, and determine that a sequence with a high correlation value (for example, a sequence with a correlation value above a threshold) is a DMRS sequence. The terminal may, for example, obtain part or all of the bit sequence indicating the SSB index based on the detected DMRS sequence. The terminal may also, for example, obtain half frame bits based on the detected DMRS sequence. Furthermore, the terminal may, for example, estimate the channel (propagation path characteristics) using the detected PBCH DMRS.

[0026] (4) PBCH Decoding The terminal may, for example, decode a PBCH that is placed in the same symbol as the DMRS for the PBCH, based on a channel estimate. The terminal may also obtain, for example, the half frame bit and the radio frame number (e.g., SFN: System Frame Number) contained in the PBCH. The terminal may also obtain a portion of the bits indicating the SSB index. The terminal may then determine the temporal 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] The above explains an example of cell search processing.

[0028] [Beam sweeping] A base station can, for example, transmit multiple SSBs with different indices at different times. For instance, a base station may set different SSB indices (for example, SSB index = 0 to 3 in Figure 2) for SSBs transmitted at different times, and transmit the SSBs using different beams for each SSB index. This process is also known as beam sweeping.

[0029] Furthermore, a set of multiple SSBs containing SSBs with different SSB indices is also called an "SSB burst set" (or SSB burst, SS burst). An SSB burst set may be transmitted, for example, within a half-frame (e.g., the first or second half of a frame).

[0030] A terminal may, for example, report to the base station the SSB index of one SSB with the highest received strength (or received quality) among the detected SSBs (e.g., the SSB with the highest received strength). Figure 3 shows an example of beam sweeping. For example, one or more terminals on the left side of Figure 3 may select SSB index 1 and send a preamble to the base station for the 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 Figure 3 may select SSB index 2 and send a preamble to the base station for the PRACH resource associated with SSB index 2.

[0031] [Coverage Expansion] 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 enables terminals with lower costs than the initial release of NR is being considered. One example of a cost-reducing technology is to reduce (in other words, limit) the number of antennas or the bandwidth supported by the terminal.

[0033] However, these technologies may reduce coverage. Therefore, technologies to compensate for coverage may be considered in the future. 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 to duplicate (or repeat) the SSB (or SSB burst set) specified in Rel-15 / 16, as shown in Figure 4, and transmit additional SSB (or SSB burst set) at different times or on different frequency resources. This method allows terminals compatible with Rel-17 and later (e.g., terminals to which RedCap or CE applies) to receive more SSB than terminals compatible with Rel-15 / 16 (e.g., referred to as Rel-15 / 16 terminals).

[0035] However, other terminals (e.g., Rel-15 / 16 terminals) that do not use the CE or RedCap mentioned above may receive (or detect) the PSS of the SSB specified in Rel-15 / 16 and the PSS of the additional SSB before cell connection. For example, other terminals may mistakenly detect the additional SSB as the SSB specified in Rel-15 / 16 and fail to synchronize.

[0036] One embodiment of this disclosure describes, for example, a method for extending SSB coverage to terminals to which CE or RedCap is applied, thereby suppressing synchronization failures in Rel-15 / 16 terminals or Rel-17 and later terminals 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 may be applied (e.g., a Rel-17 or later terminal to which CE or RedCap specification technology may be applied) may receive additional SSBs in addition to the SSBs defined in the Rel-15 / 16 specification (e.g., referred to as "legacy SSBs") when receiving SSBs.

[0038] In one embodiment of the present disclosure, the additional SSB may include, for example, at least one of PSS, SSS, PBCH, and DMRS for PBCH. The additional SSB may be located on resources that differ from the legacy SSB, for example, at least one of the time resources and frequency resources. The additional SSB may also differ from the legacy SSB, for example, at least one of the sequence and signal arrangement.

[0039] As a result, in one embodiment of the present disclosure, for example, the number of SSB receptions in a terminal to which CE may apply can be increased, and the receivable coverage can be expanded. Also, in one embodiment of the present disclosure, for example, other terminals different from those to which CE may apply (e.g., Rel-15 / 16 terminals, or Rel-17 or later terminals to which technologies defined in the CE or RedCap specifications do not apply) are less likely to falsely detect additional SSBs, and synchronization failures can be suppressed.

[0040] For convenience, in the following explanation, when we refer to a terminal simply as "terminal" or "terminal 200" (described later), we mean a terminal to which CE may apply. Also, for convenience, when we refer to other terminals, we mean, for example, Rel-15 / 16 terminals, or Rel-17 or later terminals to which technologies defined in CE or RedCap specifications do not apply.

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

[0042] [Overview of the communication system] The communication system according to this embodiment includes a base station 100 and a terminal 200.

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

[0044] Figure 6 is a block diagram showing a partial configuration example of terminal 200 according to this embodiment. In terminal 200 shown in Figure 6, the receiving unit 202 (corresponding to, for example, a receiving circuit) receives a first synchronization signal block (e.g., legacy SSB) and a second synchronization signal block (e.g., additional SSB) in which at least one of the sequence and signal arrangement differs from that of the first synchronization signal block. The control unit 208 (corresponding to, for example, a control circuit) performs a cell search based on the first synchronization signal block and the second synchronization signal block.

[0045] [Base station configuration] Figure 7 is a block diagram showing an example configuration of a base station 100 according to this embodiment. In Figure 7, the base station 100 includes a control unit 101, a signal generation unit 102, an encoding / modulation unit 103, a signal arrangement unit 104, a transmission unit 105, an antenna 106, a receiving unit 107, and a demodulation / decoding unit 108.

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

[0047] The signal generation unit 102 may, for example, generate PSS, SSS, and DMRS based on information about the sequence input from the control unit 101, and output the generated signals to the signal arrangement unit 104.

[0048] The encoding and modulation unit 103 may, for example, error-correct encoding and modulation of the downstream data and broadcast information, and output the modulated signal to the signal arrangement unit 104.

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

[0050] For example, the signal placement unit 104 may place PSS in the PSS resource, SSS in the SSS resource, DMRS in the DMRS resources within the PDSCH and PBCH, downlink data in the PDSCH resource, and broadcast information in the PBCH resource.

[0051] The signal placement unit 104 outputs the signals assigned to each resource to the transmission unit 105.

[0052] The transmitting unit 105 performs wireless transmission processing, such as frequency conversion using a carrier wave, on the signal input from the signal arrangement unit 104, and outputs the processed signal to the antenna 106.

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

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

[0055] The receiving unit 107 performs wireless reception processing, such as frequency conversion, on the signal input from the antenna 106, and outputs the processed signal to the demodulation / decoding unit 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] Figure 8 is a block diagram showing an example configuration of terminal 200 according to this embodiment.

[0058] In Figure 8, the terminal 200 includes an antenna 201, a receiving unit 202, a signal separation unit 203, a signal detection unit 204, a channel estimation unit 205, a demodulation / decoding unit 206, a broadcast information receiving unit 207, a control unit 208, an encoding / modulation unit 209, and a transmitting unit 210.

[0059] Antenna 201 receives downlink signals transmitted by base station 100 and outputs them to receiving unit 202. Antenna 201 also radiates uplink signals input from transmitting unit 210 to base station 100.

[0060] The receiving unit 202 performs wireless reception processing, such as frequency conversion, on the signal input from the antenna 201, and outputs the processed signal to the signal separation unit 203.

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

[0062] The signal detection unit 204 may, for example, detect a PSS, SSS, or DMRS sequence from the signal input from the signal separation unit 203, in accordance with instructions from the control unit 208. For example, the signal detection unit 204 may perform correlation detection between sequence information (e.g., a replica of the sequence) input from the control unit 208 and the signals on each resource (e.g., any of the PSS, SSS, and DMRS resources) input from the signal separation unit 203. The signal detection unit 204 may, for example, output to the control unit 208 information regarding sequences and timings that have a high correlation (e.g., a correlation value above a threshold) in the correlation detection. The signal detection unit 204 may also, for example, output the detected DMRS to the channel estimation unit 205.

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

[0064] The demodulation / decoding unit 206 demodulates and error-corrects the signal input from the signal separation unit 203 (for example, a signal on a PDSCH or PBCH resource) based on the channel estimate input from the channel estimation unit 205 to obtain downstream data or broadcast information. The demodulation / decoding unit 206 outputs the broadcast information obtained by decoding to the broadcast information receiving unit 207.

[0065] The notification information receiving unit 207 extracts information contained in the notification information input from the demodulation / decoding unit 206 (for example, information regarding the timing of each SSB signal) and outputs it to the control unit 208.

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

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

[0068] The encoding and modulation unit 209 may, for example, encode and modulate an uplink signal (e.g., 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 / modulation unit 209, and outputs the processed signal to the antenna 201.

[0070] [Example of operation of base station 100 and terminal 200] Next, we will describe an example of the operation of the base station 100 and terminal 200 mentioned above.

[0071] <Example of operation 1> In example 1, for instance, at least one of the signal sequences among the PSS, SSS, and PBCH DMRS placed on each SSB may be different between the legacy SSB and the additional SSB.

[0072] Figure 9 is a flowchart showing an example of processing at base station 100 and terminal 200.

[0073] (S101) Terminal 200 may determine the series and resources (e.g., time resources and frequency resources) for legacy SSB and additional SSB based on predefined or configured information.

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

[0075] Figure 10 shows an example of legacy SSB and additional SSB related to Operation Example 1. As shown in Figure 10, the legacy SSB (e.g., SSB burst set) and the additional SSB (e.g., SSB burst set) may have different series in at least one of the PSS, SSS, and PBCH DMRS.

[0076] (S103) Terminal 200 may, for example, attempt to detect PSS. For example, terminal 200 may attempt correlation detection based on the PSS detection sequence of the legacy SSB (e.g., a replica of the sequence) and the PSS detection sequence of the additional SSB (e.g., a replica of the sequence). 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 processing S103 is a legacy SSB, terminal 200 may attempt correlation detection based on a sequence that can be used for the legacy SSB's SSS (e.g., a replica of the sequence). On the other hand, if the PSS detected in processing S103 is an additional SSB, terminal 200 may attempt correlation detection based on a sequence that can be used for the additional SSB's SSS (e.g., a replica of the sequence). This allows terminal 200 to identify an SSS included in either the legacy SSB burst set or the additional SSB burst set.

[0078] Terminal 200 may, for example, return to processing S103 if no SSS is detected. If terminal 200 detects an SSS, for example, it may calculate a cell ID (e.g., PCI) based on the identified PSS and SSS series. Hereafter, "calculation" may be read as "determination" or "identification".

[0079] (S105) For example, if the PSS detected in processing S103 is a legacy SSB, terminal 200 may attempt to detect a PBCH DMRS based on a sequence (e.g., a replica of the sequence) that can be used for the legacy SSB's PBCH DMRS. Also, if the PSS detected in processing S103 is an additional SSB, terminal 200 may attempt to detect a correlation based on a sequence (e.g., a replica of the sequence) that can be used for the additional SSB's PBCH DMRS. This allows terminal 200 to identify a sequence of PBCH DMRS included in either the legacy SSB burst set or the additional SSB burst set.

[0080] Terminal 200 may, for example, return to processing S103 or S104 if no DMRS is detected. If terminal 200 detects a DMRS, for example, it may calculate an SSB index (or a portion of the bits indicating the SSB index) based on the identified PBCH DMRS sequence. Terminal 200 may also estimate the channel using the detected PBCH DMRS.

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

[0082] Terminal 200 may determine the temporal position of the received SSB based, for example, on the values ​​of the SSB index, SFN, and half frame bit.

[0083] (S107) The 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, for example. At this time, when the terminal 200 detects SSBs at multiple timings within an SSB burst set, for example, it may transmit the preamble based on the SSB index of the SSB with higher reception intensity or reception quality among the multiple SSBs (e.g., the SSB with the highest reception intensity or reception quality).

[0084] Above, an example of the processes of the base station 100 and the terminal 200 has been described.

[0085] In this way, the terminal 200 that grasps the series of additional SSBs in the process of S101 can receive additional SSBs in addition to legacy SSBs, so the reception quality of SSBs is improved and the receivable coverage can be extended.

[0086] On the other hand, other terminals that do not grasp the series of additional SSBs are less likely to detect the series of additional SSBs, so the possibility of misdetecting additional SSBs can be reduced.

[0087] Next, an example of generating additional SSBs in Operation Example 1 will be described.

[0088] For example, the series for additional SSBs may be, for example, a series obtained by rearranging the series (e.g., elements of the series) for legacy SSBs.

[0089] (Generation Example 1) The base station 100 and the terminal 200 may, for example, reverse (in other words, invert) the order of the elements of the length-127 sequence d PSS (n) in the PSS of the legacy SSB to generate the length-127 sequence d PSS_Add (n) in the PSS of the additional SSB. For example, the sequence d PSS_Add (n) of the PSS of the additional SSB may be a sequence obtained by reversing the order of the elements of the PSS sequence d PSS (n) for the legacy SSB according to the following formula (1).

number

[0090] (Generation example 2) The base station 100 and terminal 200 are, for example, a sequence d of length 127 in the PSS of a legacy SSB. PSS The elements of (n) are cyclically shifted (in other words, cyclic-shifted) to obtain a sequence d of length 127 in the PSS of the additional SSB. PSS_Add (n) may be generated. For example, the sequence d of the PSS of the additional SSB. PSS_Add (n) is the PSS sequence d for legacy SSB according to equation (2) below. PSS A sequence obtained by cycling through the elements of (n) is acceptable.

number

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

[0092] For example, the PSS sequence d of the additional SSB PSS_Add (n) is d PSS (n) is divided into a certain number (for example, 2), and each part is d PSS_Add (n) may be arranged at equal intervals. For example, the sequence d of the PSS of the additional SSB PSS_Add (n) is the PSS sequence d for legacy SSB according to equation (3) below. PSS A sequence obtained by interleaving the elements of (n) is acceptable.

number

[0093] Furthermore, the method of interlacing and overlapping the sequence order in Generation Example 3 is not limited to the method based on equation (3), but may be done by other methods as well.

[0094] Furthermore, in each of equations (1) to (3), n and Δ may be integers.

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

[0096] In Generation Examples 1-3, the method for generating the PSS of an additional SSB was explained as an example, but the SSS of an additional SSB or the DMRS for PBCH may be generated using the same method as for the PSS. For example, each of Generation Examples 1-3 may be applied not only to the PSS, but also to the generation of sequences of the SSS or DMRS for PBCH included in the additional SSB. For example, the signal to which a different sequence is applied between the additional SSB and the legacy SSB may be at least one of the SSS and the DMRS for PBCH.

[0097] For example, in an additional SSB, the PSS sequence may differ from that of the legacy SSB, while the SSS and PBCH DMRS sequences may be the same as those of the legacy SSB. This makes it more difficult for other terminals, such as terminal 200, to detect the additional SSB's PSS during PSS detection, thus eliminating the need to perform detection processing for the additional SSB's SSS and PBCH DMRS, and thus reducing power consumption in other terminals. Furthermore, by setting the SSS and PBCHDMRS sequences in the additional SSB to be the same as those of the legacy SSB, changes from standards such as Rel-15 / 16 can be suppressed.

[0098] Furthermore, for example, in an additional SSB, the PSS and SSS sequences may differ from those of the legacy SSB, while the PBCH DMRS sequence may be the same as that of the legacy SSB. This makes it more difficult for other terminals, such as terminal 200, to detect the PSS or SSS of the additional SSB during PSS or SSS detection, thus eliminating the need to perform the PBCH DMRS detection process for the additional SSB and reducing power consumption in other terminals. Additionally, by setting the PBCHDMRS sequence in the additional SSB to be the same as that of the legacy SSB, changes from standards such as Rel-15 / 16 can be suppressed.

[0099] Furthermore, for example, in an additional SSB, the PSS, SSS, and PBCH DMRS sequences may differ from those of the legacy SSB. This reduces, for example, false detection of the additional SSB in terminals other than terminal 200.

[0100] Furthermore, in the case of the additional SSB, it is not limited to cases where a different sequence from the legacy SSB is applied to the signal that includes the PSS; for example, a different sequence from 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 between the legacy SSB and other signals may be dynamically switched.

[0102] Furthermore, while examples 1-3 described cases where the sequence for the additional SSB is generated based on the sequence for the legacy SSB, the model is not limited to these cases. For example, the sequence for one of the legacy SSB and the additional SSB may be a sequence obtained by rearranging the 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 of operation 2> In example 2, for instance, the signal arrangement (e.g., signal arrangement order) of the PSS, SSS, and PBCH may differ between the legacy SSB and the additional SSB. For example, the position of at least one of the SSS and PBCH (or DMRS for PBCH) relative to the position of the PSS within the additional SSB resource may differ from that of the legacy SSB.

[0104] The processing at the base station 100 and terminal 200 may be the same as the processing shown in Figure 9, for example.

[0105] (S101) Terminal 200 may determine the series and resources (e.g., time resources and frequency resources) for legacy SSB and additional SSB based on predefined or configured information. For example, the series for additional SSB may be the same as the series for legacy SSB.

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

[0107] (S103) Terminal 200 may, for example, attempt to detect PSS. For example, terminal 200 may attempt correlation detection based on a sequence of PSS detections for legacy SSBs (e.g., a replica of the sequence). 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 assuming) the location of the SSB resource when the PSS detected in processing S103 is a legacy SSB or an additional SSB. By doing so, terminal 200 may, for example, identify a series of SSSs included in either the legacy SSB burst set or the additional SSB burst set.

[0109] Terminal 200 may, for example, return to processing S103 if no SSS is detected. If terminal 200 detects an SSS, for example, it may determine (e.g., calculate) a cell ID (e.g., PCI) based on the identified PSS and SSS sequences.

[0110] (S105) Terminal 200 may, for example, attempt to detect DMRS for PBCH. For example, terminal 200 may attempt correlation detection by assuming (or assuming) the location of both legacy SSB and additional SSB PBCH resources. This will allow terminal 200 to identify any series of DMRS for PBCH included in the legacy SSB burst set or the additional SSB burst set.

[0111] Terminal 200 may, for example, return to processing S103 or S104 if no DMRS is detected. If terminal 200 detects a DMRS, for example, it may calculate an SSB index (or a portion of the bits indicating the SSB index) based on the identified PBCH DMRS sequence. Terminal 200 may also estimate the channel using the detected PBCH DMRS.

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

[0113] Terminal 200 may determine the temporal position of the received SSB based, for example, on the values ​​of the SSB index, SFN, and half frame bit.

[0114] (S107) Similar to Operation Example 1, terminal 200 may, for example, send a PRACH preamble in the PRACH resource associated with the SSB index obtained in processing S105 and S106. In this case, if terminal 200 has detected SSBs at multiple timings within the SSB burst set, it may, for example, send a preamble based on the SSB index of the SSB with the higher received strength or received quality among the multiple SSBs (e.g., the SSB with the highest received strength or received quality).

[0115] The above describes an example of the processing performed by the base station 100 and the terminal 200.

[0116] Thus, terminal 200, having identified the additional SSB sequence during processing in S101, can receive the additional SSB in addition to the legacy SSB, thereby improving the SSB reception quality and expanding the receivable coverage.

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

[0118] Next, we will describe an example of signal arrangement in the additional SSB in Operation Example 2.

[0119] (Layout example 1) Figure 11 shows an example configuration of the legacy SSB and additional SSB in Configuration Example 1.

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

[0121] Thus, in arrangement example 1, for example, the signal placement order of PSS and SSS is reversed between the legacy SSB and the additional SSB. In other words, the positions where PSS and SSS are placed are swapped between the legacy SSB and the additional SSB.

[0122] As a result, for example, as shown in Figure 11, the signals placed in the 0th and 2nd symbols are different in 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 of the additional SSB may be set to be common with the sequence of the legacy SSB. This makes it possible to suppress changes from standards such as Rel-15 / 16. Furthermore, the common sequence for the legacy SSB and the additional SSB enables in-phase SSB synthesis (e.g., soft-combining) at terminal 200.

[0123] (Layout example 2) Figure 12 shows an example configuration of the legacy SSB and additional SSB in configuration example 2.

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

[0125] Thus, in arrangement example 2, for example, the signal placement order of PSS, SSS, and PBCH between the legacy SSB and the additional SSB is reversed.

[0126] As a result, as shown in Figure 12, the signals placed in the 0th and 2nd symbols are different in the legacy SSB and the additional SSB, making it possible to distinguish between them. Furthermore, for example, the sequence of the additional SSB may be set to be common with the sequence of the legacy SSB. This helps to suppress changes from standards such as Rel-15 / 16. Additionally, the common sequence between the legacy SSB and the additional SSB enables in-phase SSB synthesis (e.g., soft combining) at terminal 200.

[0127] Furthermore, in Operation Example 2, even with the additional SSB, the SSS is arranged surrounded by the PBCH, similar to the legacy SSB, which suppresses interference to the SSS and improves the performance of SSS decoding.

[0128] The above describes the layout examples 1 and 2.

[0129] Furthermore, the relative positions of each signal in the additional SSB are not limited to arrangement example 1 and arrangement example 2, and only need to differ from the relative positions of each signal in legacy SSB (for example, the arrangement in at least one of the time resources and frequency resources).

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

[0131] Furthermore, the sequence set for at least one of the signals included in the additional SSB is not limited to being the same as the sequence of signals included in the legacy SSB; as in Operation Example 1, a different sequence from that of the legacy SSB may be set.

[0132] <Example of operation 3> In Operation Example 3, for example, the additional SSB may include some of the signals from PSS, SSS, and PBCH. For example, in the additional SSB, PBCH may be included (or transmitted), while PSS and SSS may not be included (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 at the base station 100 and terminal 200 may be the same as the processing shown in Figure 9, for example.

[0134] (S101) Similar to Operation Example 2, terminal 200 may determine the series and resources (e.g., time resources and frequency resources) for the legacy SSB and additional SSB based on predefined or configured information. For example, the series for the additional SSB may be the same as the series for the legacy SSB.

[0135] (S102) Base station 100 may, for example, transmit legacy SSB and additional SSB to terminal 200. For example, base station 100 may transmit legacy SSB burst set and additional SSB burst set using at least one different time resource and frequency resource. Also, base station 100 may, for example, transmit PBCH in additional SSB, but not transmit PSS and SSS.

[0136] Figure 13 shows an example of legacy SSB and additional SSB related to Operation Example 3. As shown in Figure 13, in legacy SSB (e.g., SSB burst set), PSS, SSS, and PBCH may be transmitted. On the other hand, as shown in Figure 13, in additional SSB (e.g., SSB burst set), PBCH may be transmitted, and PSS and SSS may not be transmitted. In other words, the signal arrangement of the SSB (e.g., presence or absence of signals) may differ between legacy SSB and additional SSB.

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

[0139] Terminal 200 may, for example, return to processing S103 if no SSS is detected. If terminal 200 detects an SSS, for example, it may calculate a cell ID (e.g., PCI) based on the identified PSS and SSS sequences.

[0140] (S105) Terminal 200 may, for example, attempt to detect DMRS for PBCH. For example, terminal 200 may attempt correlation detection by assuming (or assuming) the location of both legacy SSB and additional SSB PBCH resources. This will allow terminal 200 to identify any series of DMRS for PBCH included in the legacy SSB burst set or the additional SSB burst set.

[0141] Terminal 200 may, for example, return to processing S103 or S104 if no DMRS is detected. If terminal 200 detects a DMRS, for example, it may calculate an SSB index (or a portion of the bits indicating the SSB index) based on the identified PBCH DMRS sequence. Terminal 200 may also estimate the channel using the detected PBCH DMRS.

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

[0143] Terminal 200 may determine the temporal position of the received SSB based, for example, on the values ​​of the SSB index, SFN, and half frame bit.

[0144] (S107) Similar to Operation Example 1, terminal 200 may, for example, send a preamble (e.g., a PRACH preamble) in the PRACH resource associated with the SSB index obtained in processing S105 and S106.

[0145] Thus, in processing S101, terminal 200, having grasped the signal configuration of the additional SSB, can receive the additional SSB in addition to the legacy SSB, thereby improving the reception quality of SSB (e.g., PBCH) and expanding the receivable coverage.

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

[0147] Furthermore, according to Operation Example 3, the base station 100 and terminal 200 do not perform PSS and SSS generation or detection processing for additional SSBs, thus suppressing an increase in processing load.

[0148] Furthermore, according to Operation Example 3, for example, since PSS and SSS are not placed on the additional SSB, the resource overhead caused by the additional SSB can be reduced.

[0149] Furthermore, the series set for the PBCH DMRS included in the additional SSB is not limited to being the same as the PBCH DMRS included in the legacy SSB; as in Operation Example 1, a different series from that of the legacy SSB may be set.

[0150] <Example of operation 4> In Operation Example 4, for example, the additional SSB may include some of the signals from PSS, SSS, and PBCH. For example, in the additional SSB, PSS may be included (or transmitted), while SSS and PBCH may not be included (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 at the base station 100 and terminal 200 may be the same as the processing shown in Figure 9, for example.

[0152] (S101) Similar to Operation Example 2, terminal 200 may determine the series and resources (e.g., time resources and frequency resources) for the legacy SSB and additional SSB based on predefined or configured information. For example, the series for the additional SSB may be the same as the series for the legacy SSB.

[0153] (S102) Base station 100 may, for example, transmit legacy SSB and additional SSB to terminal 200. For example, base station 100 may transmit legacy SSB burst set and additional SSB burst set using at least one different time resource and frequency resource. Also, base station 100 may, for example, transmit PSS in additional SSB, but not SSS and PBCH.

[0154] Figure 14 shows an example of legacy SSB and additional SSB related to Operation Example 4. As shown in Figure 14, in legacy SSB (e.g., SSB burst set), PSS, SSS, and PBCH may be transmitted. On the other hand, as shown in Figure 14, in additional SSB (e.g., SSB burst set), PSS may be transmitted, but SSS and PBCH may not be transmitted. In other words, the signal arrangement of the SSB (e.g., presence or absence of signals) may differ between legacy SSB and additional SSB.

[0155] (S103) Terminal 200 may, for example, attempt to detect PSS. For example, terminal 200 may attempt correlation detection based on a sequence of PSS detections for the legacy SSB (e.g., a replica of the sequence). For example, terminal 200 may identify the timing and sequence of any PSS included in the legacy SSB burst set or the 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 assuming) the location of the SSS resource for both cases in processing S103, where the PSS detected is a legacy SSB and where it is an additional SSB. By doing so, terminal 200 may, for example, identify a series of SSS included in the legacy SSB burst set.

[0157] Terminal 200 may, for example, return to processing S103 if no SSS is detected. If terminal 200 detects an SSS, for example, it may calculate a cell ID (e.g., PCI) based on the identified PSS and SSS sequences.

[0158] (S105) Terminal 200 may, for example, attempt to detect DMRS for PBCH. For example, terminal 200 may attempt correlation detection by assuming (or assuming) the location of the legacy SSB's PBCH resources. This allows terminal 200 to identify any series of DMRS for PBCH included in the legacy SSB burst set.

[0159] Terminal 200 may, for example, return to processing S103 or S104 if no DMRS is detected. If terminal 200 detects a DMRS, for example, it may calculate an SSB index (or a portion of the bits indicating the SSB index) based on the identified PBCH DMRS sequence. Terminal 200 may also estimate the channel using the detected PBCH DMRS.

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

[0161] Terminal 200 may determine the temporal position of the received SSB based, for example, on the values ​​of the SSB index, SFN, and half frame bit.

[0162] (S107) Similar to Operation Example 1, terminal 200 may, for example, send a preamble (e.g., a PRACH preamble) in the PRACH resource associated with the SSB index obtained in processing S105 and S106.

[0163] Thus, in processing S101, terminal 200, having grasped the signal configuration of the additional SSB, can receive the additional SSB in addition to the legacy SSB, thereby improving the reception quality of SSB (e.g., PSS) and expanding the receivable coverage.

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

[0165] Furthermore, according to Operation Example 4, the base station 100 and terminal 200 do not perform generation or detection processing of SSS and PBCH for the additional SSB, thus suppressing an increase in processing load.

[0166] Furthermore, according to Operation Example 4, for example, since the SSS and PBCH are not placed in the additional SSB, the resource overhead of the additional SSB can be reduced. Also, terminal 200 only needs to buffer the PSS for in-phase synthesis (e.g., soft-combining) of the legacy SSB and the additional SSB, and does not need to buffer the SSS and PBCH, thus reducing the memory size.

[0167] Furthermore, the series set in the PSS included in the additional SSB is not limited to being the same as the PSS included in the legacy SSB; as in Operation Example 1, a different series from the legacy SSB series may be set.

[0168] Next, we will explain an example of PSS placement in an additional SSB.

[0169] (Layout example 1) Figure 15 shows an example of the arrangement of legacy SSB and additional SSB in arrangement example 1.

[0170] As shown in Figure 15, the PSS of an additional SSB may be placed in a resource that is temporally close to the PSS of a legacy SSB (for example, the symbol immediately preceding it).

[0171] This allows terminal 200 to shorten the time it takes to complete PSS detection, even when using a combination of legacy SSB and additional SSB for reception processing.

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

[0173] (Layout example 2) Figure 16 shows an example of the arrangement of legacy SSB and additional SSB in arrangement example 2.

[0174] As shown in Figure 16, the PSS of the additional SSB may be located on time resources (e.g., symbols) that are common (e.g., identical) to the PSS of the legacy SSB, and on frequency resources that are different from the PSS of the legacy SSB. In other words, the PSS of the additional SSB may be frequency-division multiplexed (FDM) on the same time resources as the PSS of the legacy SSB.

[0175] This allows terminal 200 to shorten the time it takes to complete PSS detection, even when using a combination of legacy SSB and additional SSB for reception processing. For example, in the example shown in Figure 16, the PSS of legacy SSB and additional SSB are placed on the same symbol, so the time it takes to complete PSS detection is shorter than in arrangement example 1.

[0176] Furthermore, for example, in a symbol where the PSS of an additional SSB and the PSS of a legacy SSB are FDM-decoded, the non-transmission of signals different from the PSS may be set for frequency resources within a threshold subcarrier of the frequency resource where the PSS of the additional SSB is located. For example, resources that are not assigned signals different from the PSS (e.g., called guard resources or additional guard resources) may be set for frequency resources near the PSS of the additional SSB. This can mitigate interference in PSS reception.

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

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

[0179] Furthermore, configuration examples 1 and 2 may be combined. For example, the PSS in the additional SSB may be placed on resources that differ from the PSS in the legacy SSB in terms of both time resources and frequency resources.

[0180] Furthermore, while Operation Example 4 described the placement of PSS in an additional SSB, the signals transmitted in an additional SSB are not limited to PSS; they may be at least one of PSS, SSS, PBCH, and DMRS for PBCH. For example, in an additional SSB, SSS may be transmitted, but PSS and PBCH may not be. The PSS placement described above may be applied to the SSS placement in the additional SSB. This allows for extended SSS reception coverage.

[0181] <Example of operation 5> Example 5 describes an example of the deployment resources for an additional SSB. Note that Example 5 may be combined with any of Examples 1 to 4, for example.

[0182] [Variations in the placement of additional SSBs] The following describes variations in the placement of additional SSBs.

[0183] (Variation 1) The additional SSB may be deployed to a different time resource than the one where the legacy SSB is deployed.

[0184] This configuration allows base station 100 to transmit legacy SSB and additional SSB using different time resources. For example, compared to a method where legacy SSB and additional SSB are FDM-transmitted, the transmit power allocated to each SSB in each time resource can be set higher. Therefore, the reception quality of each SSB at terminal 200 can be improved.

[0185] (Variation 2) The additional SSB may be deployed on a different frequency resource than the one where the legacy SSB is deployed.

[0186] For example, legacy SSBs in a primary cell (Pcell) may be transmitted on subcarriers indicated by a defined synchronization raster (SS raster). On the other hand, 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 additional SSB raster.

[0187] This reduces the possibility, for example, that other terminals different from terminal 200 (e.g., Rel-15 / 16 terminals) may falsely detect additional SSBs.

[0188] (Variation 3) The additional SSB may be time-division multiplexed (TDM) on a frequency resource common to (e.g., identical to) the frequency resource where the legacy SSB is deployed. This configuration reduces the processing load on terminal 200, as it does not need to monitor multiple frequency bands when detecting the legacy SSB and the additional SSB.

[0189] Furthermore, the additional SSB may be deployed using FDM in a time resource shared with (e.g., identical to) the time resource where the legacy SSB is deployed. This deployment allows terminal 200 to reduce the time required to detect both the legacy SSB and the additional SSB.

[0190] The above explains variations 1 through 3.

[0191] For example, Variation 1 and Variation 2 may be combined. For example, the additional SSB may be placed in time and frequency resources that are different from both the time and frequency resources where the legacy SSB is placed.

[0192] [Multiplexing with Type 0 PDCCH] The additional SSB may, for example, TDM or FDM with either or both of the resources of a Type 0 PDCCH (also known as Type0-PDCCH, CORESET 0 (CONtrol REsource SET 0), or Search Space 0), or the resources of a PDSCH allocated by the said Type 0 PDCCH.

[0193] For example, if the base station 100 sets the value of "SS / PBCH block and CORESET multiplexing pattern" to 2 or 3, that is, if the frequency resources of the above-mentioned type 0 PDCCH or PDSCH are different from the frequency resources of the legacy SSB, the additional SSB may be TDM in the same frequency resources as the above-mentioned type 0 PDCCH or PDSCH. This allows the terminal 200 to receive the additional SSB, type 0 PDCCH and PDSCH within a relatively narrow frequency band.

[0194] Figure 17 shows an example where the value for the SS / PBCH block and CORESET multiplexing pattern is set to 2. In the example shown in Figure 17, the additional SSB is TDM'd on a frequency resource shared with the type 0 PDCCH and the PDSCH allocated by the type 0 PDCCH.

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

[0196] Figure 18 shows an example where the value for the SS / PBCH block and CORESET multiplexing pattern is set to 1. In the example shown in Figure 18, the additional SSB is FDMed using a time resource shared with the PDSCH allocated by the type 0 PDCCH, but this is not limited to this example; for example, it may be FDMed using a time resource shared with the type 0 PDCCH.

[0197] Furthermore, the method for multiplexing additional SSBs with type 0 PDCCHs may be determined and applied regardless of the values ​​of the SS / PBCH block and CORESET multiplexing pattern.

[0198] Furthermore, the values ​​of the SS / PBCH block and CORESET multiplexing pattern may be identified by associating them with values ​​notified as controlResourceSetZero, searchSpaceZero, or pdcch-ConfigSIB1, which are higher-layer parameters included in the Master Information Block (MIB) transmitted by the PBCH. In addition, the aforementioned PDSCH may transmit, for example, RMSI (ReMaining System Information) or SIB1 (System Information Block Type 1).

[0199] [Identification and notification of the deployment method for additional SSBs] In the processing of S101 in each of the above-described operation examples, the method by which terminal 200 identifies information regarding legacy SSB and additional SSB (for example, information regarding the series and resource placement method) 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 SSB and additional SSB may be based on explicit or implicit instructions (e.g., indication or configuration) from base station 100. These instructions may be communicated to terminal 200 by, for example, at least one of DCI and higher-layer signals.

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

[0202] Furthermore, if a legacy SSB burst set is placed in either the first half of a frame (e.g., the first half frame) or the second half of a frame (e.g., the second half frame) (and not in the other half), an additional SSB burst set may be placed in the other half. In this case, the SSB resource placement within the half frame may be common (e.g., identical) for both the legacy SSB and the additional SSB.

[0203] Figure 19 shows an example of the placement of legacy SSB and additional SSB. In Figure 19, for example, the legacy SSB is placed in the first half frame and the additional SSB is placed in the second half frame. Also, for example, as shown in Figure 19, if the legacy SSB is placed in symbols 4, 8, 16, and 20 of one half frame, terminal 200 may determine that the additional SSB is placed in symbols 4, 8, 16, and 20 of the other half frame.

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

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

[0206] Figure 20 shows an example of a legacy SSB burst set and an additional SSB burst set. In Figure 20, for example, the legacy SSB burst set contains 4 SSBs, and the additional SSB burst set contains 2 SSBs. In the example in Figure 20, for example, the resource overhead of the additional SSB can be reduced. Also, since the processing related to the additional SSB can be reduced, power consumption at the base station 100 and terminal 200 can be reduced.

[0207] Note that the number of SSBs in the legacy SSB burst set and the additional SSB burst set is not limited to the example shown in Figure 20, and other numbers are also acceptable.

[0208] Furthermore, the number of SSB burst sets sent 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 sent as additional SSBs may be an integer multiple of the number of legacy SSB burst sets.

[0209] Figure 21 shows an example of a legacy SSB burst set and an additional SSB burst set. In Figure 21, for example, the number of SSB burst sets sent as an additional SSB (e.g., 3 sets) is set to three times the number of legacy SSB burst sets (e.g., 1 set). Note that the number of SSB burst sets set as an additional SSB is not limited to the example shown in Figure 21 and may be any other number.

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

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

[0212] Furthermore, when multiple additional SSB burst sets are transmitted, at least one of the sequence and signal configurations set in each additional SSB burst set may be common. This helps to reduce the complexity of the decoding process for the additional SSBs at terminal 200.

[0213] Furthermore, if multiple additional SSB burst sets are transmitted, at least one of the sequences and signal configurations set in each additional SSB burst set may be different.

[0214] [Unlicensed Band] Each of the above operational examples may be applied, for example, to communications in unlicensed bands (also known as unlicensed spectrum or shared spectrum).

[0215] At this time, among the SSB candidates (for example, SSB candidates), the first to be sent after completing the career sense (also called Listen Before Talk (LBT) or Channel Clear Assessment (CCA)) is N SSB QCL In N SSB candidates, legacy SSB is transmitted, SSB QCL Additional SSBs may be transmitted in SSB candidates that follow this SSB. SSB QCL This may also be a value notified to terminal 200 by a higher layer or DCI.

[0216] Figure 22 shows, as an example, N SSBQCL Figure 22 shows an example of SSB configuration when =4 and there are 10 SSB candidates (for example, SSB candidate index 0-9). In Figure 22, for example, legacy SSB is sent to 4 SSB candidates with SSB candidate index=1-4 after LBT is completed, and additional SSB is sent to 5 other SSB candidates with SSB candidate index=5-9.

[0217] The above describes examples of the operation of the base station 100 and terminal 200.

[0218] Furthermore, parameters such as the sequence length and type of DMRS for PSS, SSS, and PBCH, the arrangement of signals in SSB, and the 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 examples described above.

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

[0220] This allows terminal 200, to which CE or RedCap is applied, to extend the receivable SSB coverage. Therefore, according to this embodiment, the SSB reception quality at terminal 200 can be improved. Furthermore, for example, Rel-15 / 16 terminals, or other terminals that are Rel-17 or later and to which the technologies defined in the CE or RedCap specifications are not applied, false detection of additional SSBs can be suppressed, and synchronization failures can be reduced.

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

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

[0223] Furthermore, in the additional SSB, a different sequence from the legacy SSB sequence may be applied to the PSS and SSS, while a sequence common to the legacy SSB sequence may be applied to other signals (e.g., 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 SSS, and attempt detection assuming the legacy SSB when detecting other signals (e.g., DMRS for PBCH), thereby reducing the processing burden on terminal 200.

[0224] Furthermore, in the additional SSB, a different series from the legacy SSB series may be applied to the PSS, SSS, and PBCH DMRS. This reduces the possibility of other terminals (for example, Rel-15 / 16 terminals, or Rel-17 or later terminals to which technologies defined in CE or RedCap specifications do not apply) falsely detecting the additional SSB.

[0225] Furthermore, a different series from the legacy SSB may be applied to any one or more combinations of the PSS, SSS, and PBCH DMRS included in the additional SSB.

[0226] (Transmission power) In the embodiments described above, the additional SSB may be transmitted at a higher power than, for example, the legacy SSB. This expands the coverage over which the additional SSB can be received.

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

[0228] Alternatively, the information carried by the PBCH of the additional SSB may differ 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 that PBCH is an "additional SSB". This reduces the possibility, for example, that other terminals different from terminal 200 may mistakenly detect the additional SSB.

[0229] (Reception processing by terminal 200) Terminal 200 may, for example, receive and decode legacy SSB and additional SSB individually. In other words, terminal 200 may, for example, receive and decode legacy SSB and additional SSB without common-mode combining (e.g., soft-combining). This allows terminal 200 to receive each SSB even if the sequence or signal configuration (e.g., the order of signals) of legacy SSB and additional SSB is different.

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

[0231] Furthermore, terminal 200 does not need to receive legacy SSBs, for example, by receiving additional SSBs. This reduces the power consumption of the receiving process in terminal 200.

[0232] (Measurement of Radio Resource Management (RRM) and Radio Link Monitoring (RLM)) For example, terminal 200 and other terminals different from terminal 200 may perform RRM measurement and RLM measurement using legacy SSB or additional SSB. In this case, information regarding the additional SSB transmitted in the current cell or a nearby cell may be notified to terminal 200. This enables RRM or RLM measurement using the additional SSB, thereby improving measurement accuracy.

[0233] (Device type, identification) Terminal 200 may be, for example, a “RedCap terminal” or a “CE terminal.” Alternatively, terminal 200 may be a terminal having at least one of the following characteristics (in other words, traits, attributes, or capabilities): (1) A terminal that notifies (e.g., reports) to base station 100 that it is a terminal subject to coverage extension, a terminal that receives repeatedly transmitted signals, 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 in which the number of implemented receiving antennas is below a threshold (for example, threshold = 1). - Terminals with a number of supported receiving antenna ports below a certain threshold (e.g., threshold = 2). - A terminal whose maximum number of supported Multiple-Input Multiple-Output (MIMO) layers (or rank) is below a threshold (e.g., threshold = 2). - A terminal capable of receiving SSB in a frequency band above a certain threshold (e.g., Frequency Range 2 (FR2)). - A terminal with a processing time equal to or greater than a threshold value. - A terminal with an available transport block size (TBS) equal to or less than a threshold value. - A terminal with an available number of MIMO transmission layers equal to or less than a threshold value. - A terminal with an available modulation order equal to or less than a threshold value. - A terminal with an available number of Hybrid Automatic Repeat request (HARQ) processes equal to or less than a threshold value. - A terminal that supports Rel-17 and later.

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

[0235] (numerology) The bandwidth of the SSB may change according to the set numerology or subcarrier spacing.

[0236] (Control signal) In the above-described embodiment, the control signal may be a PDCCH that transmits DCI of the physical layer, or may be MAC or RRC of the upper layer.

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

[0238] (Uphill rink / Downhill rink) In the above embodiment, a synchronization signal or PBCH, which is a downlink signal, was described as an example, but the method is not limited to these and can also be applied to uplink signals, such as PUSCH or PRACH.

[0239] (Notification channel / Data channel / Control channel) In the above embodiment, a PBCH used for cell search was described as an example, but the invention is not limited to these and may also be applied to a PDSCH used for data transmission or a PDCCH used for transmitting control information.

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

[0241] (Time interval) In the above embodiment, the unit of time resource is not limited to one or a combination of slots and symbols, but may also be a time resource unit such as a frame, superframe, subframe, slot, time slot subslot, minislot, or symbol, OFDM (Orthogonal Frequency Division Multiplexing) symbol, SC-FDMA (Single Carrier - Frequency Division Multiplexing) symbol, or any other time resource unit. Furthermore, the number of symbols contained in one slot is not limited to the number of symbols exemplified in the above embodiment, but may be any other number of symbols.

[0242] (Application to side links) The above embodiment may also be applied to V2X (Vehicle to Everything) or Sidelink communication used for terminal-to-terminal communication. In that case, PDCCH may be replaced with PSCCH (Physical Sidelink Control Channel), PUSCH / PDSCH with PSSCH (Physical Sidelink Shared Channel), and PUCCH with PSFCH (Physical Sidelink Feedback Channel).

[0243] <5G NR System Architecture and Protocol Stack> 3GPP is continuing work on the next release of fifth-generation mobile phone technology (also simply called "5G"), which includes the development of new radio access technologies (NR) operating in the frequency range up to 100 GHz. The initial version of the 5G standard was completed at the end of 2017, which will enable the prototyping and commercial deployment of devices (e.g., smartphones) that comply with the 5G NR standard.

[0244] For example, the system architecture as a whole assumes an NG-RAN (Next Generation - Radio Access Network) with gNBs. The gNBs provide the UE-side termination for the user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocols of the NG radio access. The gNBs are connected to each other by Xn interfaces. Furthermore, the gNBs are connected to the NGC (Next Generation Core) by Next Generation (NG) interfaces, more specifically to the AMF (Access and Mobility Management Function) (e.g., a specific core entity performing AMF) by NG-C interfaces, and to the UPF (User Plane Function) (e.g., a specific core entity performing UPF) by NG-U interfaces. The NG-RAN architecture is shown in Figure 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 PDCP (Packet Data Convergence Protocol (see section 6.4 of TS 38.300)) sublayer, RLC (Radio Link Control (see section 6.3 of TS 38.300)) sublayer, and MAC (Medium Access Control (see section 6.2 of TS 38.300)) sublayer, which are terminated on the network side in gNB. Additionally, a new Access Stratum (AS) sublayer (SDAP: Service Data Adaptation Protocol) is introduced on top of PDCP (see, for example, 3GPP TS 38.300, section 6.5). Furthermore, a control plane protocol stack is defined for NR (see, for example, TS 38.300, section 4.4.2). An overview of Layer 2 functionality is described in section 6 of TS 38.300. The functions of the PDCP sublayer, RLC sublayer, and MAC sublayer are listed in sections 6.4, 6.3, and 6.2 of TS 38.300, respectively. The functions of the RRC layer are listed in section 7 of TS 38.300.

[0246] For example, the Medium-Access-Control layer handles scheduling and scheduling-related functions, including the multiplexing of logical channels and the handling of various neural networks.

[0247] For example, the Physical Layer (PHY) is responsible for coding, PHY HARQ processing, modulation, multi-antenna processing, and mapping signals to appropriate physical time-frequency resources. The Physical Layer also handles the mapping of transport channels to physical channels. The Physical Layer provides services to the MAC layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used for transmitting a particular transport channel, and each transport channel is mapped to a corresponding physical channel. For example, physical channels include uplink physical channels such as PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel), and downlink physical channels such as PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), and PBCH (Physical Broadcast Channel).

[0248] NR use cases / deployment scenarios may include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine type communications (mMTC), each with diverse requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps on the downlink and 10 Gbps on the uplink) and effective (user-experienced) data rates approximately three times that of IMT-Advanced. URLLC, on the other hand, imposes more stringent requirements for ultra-low latency (0.5 ms for both UL and DL for user plane latency) and high reliability (1-10⁻⁵ within 1 ms). Finally, mMTC preferably has a high connectivity density (1,000,000 devices / km² in urban environments). 2 ), wide coverage in harsh environments, and extremely long-lasting batteries (15 years) for low-cost devices may be required.

[0249] Therefore, an OFDM neurology suitable for one use case (e.g., subcarrier spacing, OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) may not be effective for other use cases. For example, low-latency services may preferably require a shorter symbol length (and thus a larger subcarrier spacing) and / or fewer symbols per scheduling interval (also known as TTI) than mMTC services. Furthermore, deployment scenarios with large channel delay spreads may preferably require a longer CP length than scenarios with short delay spreads. The subcarrier spacing may be optimized on a case-by-case basis to maintain similar CP overhead. There may be one or more subcarrier spacing values ​​supported by NR. Accordingly, subcarrier spacings of 15kHz, 30kHz, 60kHz, etc. are currently being considered. The symbol length Tu and subcarrier spacing Δf are directly related by the equation Δf = 1 / Tu. Similar to LTE systems, the term “resource element” can be used to mean the smallest resource unit consisting of one subcarrier for the length of one OFDM / SC-FDMA symbol.

[0250] In the new 5G-NR wireless system, resource grids for subcarriers and OFDM symbols are defined for each neurology and each carrier, for both the uplink and downlink. Each element of the resource grid is called a resource element and is identified based on the frequency index in the frequency domain and the symbol position in the time domain (see 3GPP TS 38.211 v15.6.0).

[0251] <Functional separation between NG-RAN and 5GC in 5G NR> Figure 24 shows the functional separation between NG-RAN and 5GC. The logical nodes of NG-RAN are gNB or ng-eNB. 5GC has logical nodes AMF, UPF, and SMF.

[0252] For example, gNB and ng-eNB host the following main functions: - Functions of radio resource management such as radio bearer control, radio admission control, connection mobility control, and dynamic allocation (scheduling) of resources to the UE in both the uplink and downlink; - IP header compression, encryption, and integrity protection of data; - Selection of the AMF during UE attachment when it is not possible to determine the routing to the AMF from the information provided by the UE; - Routing of user plane data towards the UPF; - Routing of control plane information towards the AMF; - Setup and release of connections; - Scheduling and transmission of paging messages; - Scheduling and transmission of system information messages (source: AMF or operation, admission, maintenance function (OAM)); - Configuration of measurements and measurement reports for mobility and scheduling; - Transport level packet marking in the uplink; - Session management; - Support for network slicing; - Management of QoS flows and mapping to data radio bearers; - Support for UEs in the RRC_INACTIVE state; - Delivery function of NAS messages; - Sharing of the radio access network; - Dual connectivity; - Tight cooperation between NR and E-UTRA.

[0253] The Access and Mobility Management Function (AMF) hosts the following main functions: - A function to terminate Non-Access Stratum (NAS) signaling; - Security of NAS signaling; - Security control of Access Stratum (AS); - Core Network (CN) node-to-node signaling for mobility between 3GPP access networks; - Reachability of the UE in idle mode (including control and execution of paging retransmissions); - Management of registration areas; - Support for intra-system and inter-system mobility; - Access authentication; - Access authorization including roaming permission checks; - Mobility management and control (enrollment and policies); - Support for network slicing; - Selection of Session Management Function (SMF).

[0254] Furthermore, the User Plane Function (UPF) hosts the following main functions: - Anchor points for intra-RAT mobility / inter-RAT mobility (where applicable); - External PDU (Protocol Data Unit) session points for interconnection with data networks; - Routing and forwarding of packets; - Packet inspection and enforcement of policy rules in the user plane; - Reporting traffic usage; - Uplink classifier to support routing of traffic flow to data networks; - Branching Point for supporting multi-homed PDU sessions; - QoS processing for the user plane (e.g., packet filtering, gating, UL / DL rate enforcement); - Verification of uplink traffic (mapping to the QoS flow of the SDF); - Downlink packet buffering and trigger 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 for configuring UEs and gNBs. During this transition, the AMF prepares UE context data (including, for example, PDU session context, security key, UE Radio Capability, UE Security Capabilities, etc.) and sends it to the gNB along with an Initial Context Setup Request. The gNB then activates AS security together with the UE. This is done by the gNB sending a SecurityModeCommand message to the UE, to which the UE responds with a SecurityModeComplete message. Subsequently, the gNB sends an RRCReconfiguration message to the UE, and upon receiving an RRCReconfigurationComplete from the UE, the gNB reconfigures itself to set up the Signaling Radio Bearer 2 (SRB2) and Data Radio Bearer (DRB). For signaling-only connections, the RRCReconfiguration step is omitted because SRB2 and DRB are not set up. Finally, gNB notifies AMF that the setup procedure is complete with an Initial Context Setup Response.

[0258] Accordingly, this disclosure provides a 5th Generation Core (5GC) entity (e.g., AMF, SMF, etc.) comprising a control circuit that establishes a Next Generation (NG) connection with a gNodeB during operation, and a transmission unit that sends an initial context setup message to the gNodeB via the NG connection during operation so that a signaling radio bearer between the gNodeB and the user equipment (UE) is set up. Specifically, the gNodeB transmits Radio Resource Control (RRC) signaling, including an Information Element (IE), to the UE via the signaling radio bearer. The UE then transmits on the uplink or receives on the downlink based on the resource allocation setting.

[0259] <IMT Usage Scenarios from 2020 Onward> Figure 26 shows some use cases for 5G NR. The 3rd generation partnership project for new radio (3GPP NR) is considering three use cases envisioned by IMT-2020 to support a wide variety of services and applications. The first phase of specification development for enhanced mobile-broadband (eMBB) has been completed. Current and future work will include expanding eMBB support, as well as standardization for ultra-reliable and low-latency communications (URLLC) and massive machine-type communications (mMTC). Figure 26 shows some examples of conceptual use scenarios for IMT beyond 2020 (see, e.g., 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 key technologies to enable future applications such as wireless control of industrial production or manufacturing processes, telemedicine surgery, automation of power transmission and distribution in smart grids, and traffic safety. The ultra-high reliability of URLLC is supported by identifying technologies that meet the requirements set by TR 38.913. In NR URLLC in Release 15, a key requirement is that the target user plane latency is 0.5 ms for UL (uplink) and 0.5 ms for DL ​​(downlink). The general URLLC requirement for a single packet transmission is a block error rate (BLER) of 1E-5 for a 32-byte packet size when the user plane latency is 1 ms.

[0261] From a physical layer perspective, reliability can be improved in many ways. Current room for reliability improvement includes defining a separate CQI table for URLLC, a more compact DCI format, and PDCCH iterations. However, this room for improvement may expand towards achieving ultra-high reliability as NR becomes more stable and developed (in terms of critical requirements for NR URLLC). Specific use cases for NR URLLC in Release 15 include augmented reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0262] Furthermore, the technical enhancements targeted by NR URLLC aim to improve latency and reliability. Technical enhancements for latency improvement include configurable neurology, non-slot-based scheduling with flexible mapping, grant-free (configured grant) uplink, slot-level iteration on data channels, and preemption on downlink. Preemption means that a transmission for which a resource has already been allocated is stopped, and that allocated resource is used for other transmissions with lower latency / higher priority requirements that are requested later. Thus, transmissions that were already permitted are replaced by later transmissions. Preemption is applicable regardless of the specific service type. For example, a transmission of service type A (URLLC) may be replaced by a transmission of service type B (eMBB, etc.). Technical enhancements for reliability improvement include a dedicated CQI / MCS table for the 1E-5 target BLER.

[0263] A key characteristic of mMTC (massive machine type communication) use cases is the extremely large number of connected devices that typically transmit relatively small amounts of data that are less susceptible to latency. These devices require low cost and very long battery life. From a noise reduction (NR) perspective, utilizing a very narrow bandwidth is one solution that saves power from the user interface (UE) and extends battery life.

[0264] As mentioned above, the scope of reliability improvements in NR is expected to broaden. High reliability or very high reliability is a critical requirement in all cases, for example, for URLLC and mMTC. Several mechanisms can improve reliability from both a radio and network perspective. Generally, there are two to three key areas that can help improve reliability. These areas include compact control channel information, data channel / control channel repetition, and diversity in the frequency, time, and / or spatial domains. These areas are generally applicable to reliability improvements regardless of the specific communication scenario.

[0265] Regarding NR URLLC, further use cases with more stringent requirements are envisioned, such as factory automation, transportation, and power distribution. These stringent requirements include high reliability (up to 10⁻⁶ levels), high availability, packet size up to 256 bytes, and time synchronization down to a few microseconds (depending on the use case, the value can be 1 microsecond or a few microseconds depending on the frequency range and short latency of approximately 0.5 ms to 1 ms (e.g., 0.5 ms latency in the target user plane)).

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

[0267] <QoS Control> The 5G Quality of Service (QoS) model is based on QoS flows and supports both QoS flows that require a guaranteed flow bit rate (GBR: Guaranteed Bit Rate QoS flows) and QoS flows that do not require a guaranteed flow bit rate (non-GBR QoS flows). Therefore, at the NAS level, a QoS flow is the finest granularity of QoS differentiation within a PDU session. A QoS flow is identified within a PDU session by a QoS Flow ID (QFI) that is carried in an encapsulation header via the NG-U interface.

[0268] For each UE, the 5GC establishes one or more PDU sessions. For each UE, the NG-RAN establishes at least one Data Radio Bearers (DRB) in accordance with the PDU session, as shown above, for example, referring to Figure 25. Additional DRBs for the QoS flow of that PDU session can be configured later (when this is done is up to the NG-RAN). The NG-RAN maps packets belonging to various PDU sessions to various DRBs. NAS-level packet filters in the UE and 5GC associate UL and DL packets with QoS flows, while AS-level mapping rules in the UE and NG-RAN associate UL and DL QoS flows with DRBs.

[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) (for example, an external application server hosting 5G services, as illustrated in Figure 26) interacts with the 3GPP core network to provide services. This may involve accessing the Network Exposure Function (NEF) to support applications that affect traffic routing, or interacting with the policy framework for policy control (e.g., QoS control) (see Policy Control Function (PCF)). Based on operator deployment, Application Functions considered trusted by the operator can interact directly with the relevant Network Functions. Application Functions not authorized by the operator to directly access the Network Functions interact with the relevant Network Functions using an external exposure framework via the NEF.

[0270] Figure 27 further illustrates the functional units of the 5G architecture, namely the Network Slice Selection Function (NSSF), Network Repository Function (NRF), Unified Data Management (UDM), Authentication Server Function (AUSF), Access and Mobility Management Function (AMF), Session Management Function (SMF), and Data Network (DN, e.g., operator services, internet access, or third-party services). All or part of the core network functions and application services may be deployed and operate in a cloud computing environment.

[0271] Accordingly, the Disclosure provides an application server (e.g., AF in a 5G architecture) comprising: a transmitter that, in operation, transmits a request to at least one of the 5GC functions (e.g., NEF, AMF, SMF, PCF, UPF, etc.) that includes QoS requirements for at least one of the URLLC service, eMMB service, and mMTC service, in order to establish a PDU session including a radio bearer between the gNodeB and UE in accordance with QoS requirements; and a control circuit that, in operation, performs the service using the established PDU session.

[0272] This disclosure can be implemented as software, hardware, or software in conjunction with hardware. Each functional block used in the description of the above embodiments may be implemented partially or entirely as an integrated circuit (LSI), and each process described in the above embodiments may be controlled partially or entirely by a single LSI or a combination of LSIs. An LSI may consist of individual chips, or it may consist of a single chip that includes some or all of the functional blocks. An LSI may have data inputs and outputs. Depending on the degree of integration, LSIs may be referred to as ICs, system LSIs, super LSIs, or ultra LSIs. The method of integrated circuit implementation is not limited to LSIs, and may also be implemented with dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, an FPGA (Field Programmable Gate Array) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. This disclosure may be implemented as digital processing or analog processing. Furthermore, if advancements in semiconductor technology or other derived technologies lead to the emergence of integrated circuit technologies that replace LSIs, then naturally, it would be possible to use those technologies to integrate functional blocks. The application of biotechnology, for example, is a possibility.

[0273] This disclosure is applicable to all types of devices, systems, and equipment having communication capabilities (collectively referred to as communication equipment). Communication equipment may include a radio transceiver and a processing / control circuit. A radio transceiver may include a receiver and a transmitter, or both as functions. A radio transceiver (transmitter, receiver) may include an RF (Radio Frequency) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or similar. Non-exclusive examples of communication devices include telephones (mobile phones, smartphones, etc.), tablets, personal computers (PCs) (laptops, desktops, notebooks, etc.), cameras (digital still / video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smartwatches, tracking devices, etc.), game consoles, digital book readers, telehealth / telemedicine devices, vehicles or mobile transport with communication capabilities (cars, airplanes, ships, etc.), and combinations of the above-mentioned devices.

[0274] Communication devices are not limited to portable or movable devices, but also include all kinds of non-portable or fixed devices, devices, and systems, such as smart home devices (appliances, lighting equipment, smart meters or measuring instruments, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0275] Communication includes data communication via cellular systems, wireless LAN systems, and communication satellite systems, as well as data communication using combinations of these.

[0276] Furthermore, the communication device also includes devices such as controllers and sensors that are connected to or linked to a communication device that performs the communication functions described in this disclosure. For example, this includes controllers and sensors that generate control signals and data signals used by the communication device that performs the communication functions of the communication device.

[0277] Furthermore, communication equipment includes infrastructure facilities such as base stations, access points, and any other devices, devices, and systems that communicate with or control the aforementioned non-limited types of equipment.

[0278] A terminal according to one embodiment of the present disclosure comprises a receiving circuit that receives a first synchronization signal block and a second synchronization signal block in which at least one of the sequence and signal arrangement differs from that of the first synchronization signal block, 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 sequence of at least one signal among the first synchronization signal, the second synchronization signal, and the reference signal arranged in each synchronization signal block is different from that of 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 the 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 is a sequence obtained by reversing the order of the elements of the sequence for the other.

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

[0283] In one embodiment of the present disclosure, the sequence for one is a sequence obtained by interleaving elements of the sequence for the other.

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

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

[0286] In one embodiment of the present disclosure, the signal arrangement order of the first synchronization signal, the second synchronization signal, and the broadcast signal is 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 signals from 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 but does not include the first synchronization signal and the second synchronization signal.

[0289] In one embodiment of the present disclosure, the second synchronization signal block includes the first synchronization signal but does not include the second synchronization signal or the broadcast signal.

[0290] 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 within a threshold symbol from the time resource in which the first synchronization signal is placed in the first synchronization signal block.

[0291] In one embodiment of the present disclosure, the placement of the first synchronization signal in the second synchronization signal block is such that it shares a time resource with 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, for frequency resources within a threshold subcarrier of the frequency resource where the first synchronization signal of the second synchronization signal block is located, the transmission of a signal different from the first synchronization signal is set to be disabled.

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

[0296] All disclosures in the specification, drawings, and abstract contained in the Japanese application 2020-133006, filed on August 5, 2020, are incorporated herein by reference. [Industrial applicability]

[0297] One embodiment of this disclosure is useful for 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 Receiving Unit 108,206 Demodulation / Decoding Section 200 terminals 203 Signal separation section 204 Signal detection unit 205 Channel Estimation Unit 207 Information Receiving Unit

Claims

1. A control circuit that identifies resources different from those in the first synchronization signal block as resources for the second synchronization signal block, The system comprises a transmitting circuit that transmits the second synchronization signal block located in the resources of the second synchronization signal block, The time resource in the second synchronization signal block is indicated by an offset relative to the time resource in the first synchronization signal block. The number of the second synchronization signal blocks is less in the time domain than the number of the first synchronization signal blocks. Base station.

2. The frequency resources in the second synchronization signal block are different from the frequency resources in the first synchronization signal block. The base station according to claim 1.

3. Information regarding the resources of the first synchronization signal block and information regarding the resources of the second synchronization signal block are notified by the upper layer. The base station according to claim 1.

4. The first synchronization signal block and the second synchronization signal block are frequency multiplexed within the same time resource. The base station according to claim 1.

5. The second synchronization signal block is frequency multiplexed with the Physical Downlink Control Channel (PDCCH). The base station according to claim 1.

6. The aforementioned second synchronization signal block is used by the RedCap terminal. The base station according to claim 1.

7. Identify resources different from those in the first synchronization signal block as resources for the second synchronization signal block. The second synchronization signal block placed in the resource of the second synchronization signal block is transmitted, The time resource in the second synchronization signal block is indicated by an offset relative to the time resource in the first synchronization signal block. The number of the second synchronization signal blocks is less in the time domain than the number of the first synchronization signal blocks. Communication method.

8. The frequency resources in the second synchronization signal block are different from the frequency resources in the first synchronization signal block. The communication method according to claim 7.

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

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

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

12. The aforementioned second synchronization signal block is used by the RedCap terminal. The communication method according to claim 7.

13. A process to identify resources different from those in the first synchronization signal block as resources for the second synchronization signal block, The process of transmitting the second synchronization signal block located in the resource of the second synchronization signal block is controlled, The time resource in the second synchronization signal block is indicated by an offset relative to the time resource in the first synchronization signal block. The number of the second synchronization signal blocks is less in the time domain than the number of the first synchronization signal blocks. Integrated circuit.

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