Terminal, wireless communication system, and wireless communication method

Abstract

This invention provides a terminal, a wireless communication system, and a wireless communication method that enable more accurate measurement of channel status even before wireless resource control layer (RRC) connection. [Solution] The terminal (UE) receives a first downlink reference signal (DL-RS#1) and a second downlink reference signal (DL-RS#2). When the first downlink reference signal is received while a connection at a specific layer has not been established, it is assumed that the first downlink reference signal is in a pseudo-collocation with the second downlink reference signal.

Description

Technical Field

[0001] The present disclosure relates to a terminal that receives a downlink reference signal, a wireless communication system, and a wireless communication method.

Background Art

[0002] The 3rd Generation Partnership Project (3GPP) is standardizing the 5th generation mobile communication system (also called 5G, New Radio (NR), or Next Generation (NG)), and is also proceeding with the standardization of the next generation, called Beyond 5G, 5G Evolution, or 6G.

[0003] In Releases 15 and 16 of 3GPP, a Transmission Configuration Indication (TCI) state is indicated from the network to the User Equipment (UE) so that the UE can receive physical downlink channels, specifically, the Physical Downlink Shared Channel (PDSCH) and the Physical Downlink Control Channel (PDCCH).

[0004] The TCI state can explicitly indicate the Quasi-Colocation (QCL) relationship between a predetermined downlink reference signal (DL-RS) and the PDSCH / PDCCH. The type of QCL is defined by parameters such as the Doppler shift and the average delay that indicate the channel state (channel condition) (Non-Patent Document 1).

[0005] Before establishing a Radio Resource Control Layer (RRC) connection (which may include idle or inactive states), the UE may assume that the PDSCH / PDCCH consists of a synchronization signal block (SSB (Synchronization Signal) / PBCH (Physical Broadcast Channel) Block) and a QCL. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] 3GPP TS 38.214 V16.5.0, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Physical layer procedures for data (Release 16), 3GPP, March 2021 [Overview of the project]

[0007] As mentioned above, before RRC connection, it can be assumed that the PDSCH / PDCCH, specifically the Demodulation Reference Signal (DMRS) of the PDSCH / PDCCH, is SSB and QCL, but there is room for improvement in the UE's DMRS reception characteristics.

[0008] Specifically, even before establishing an RRC connection, if a Tracking Reference Signal (TRS) or Channel State Information-Reference Signal (CSI-RS), which has a larger resource element (RE) and transmission bandwidth than SSB, can be used, more accurate measurement of the channel state can be expected.

[0009] However, since the TCI state can only be specified after the RRC connection is established, it is not possible to specify QCL relationships using the TCI state before the RRC connection is established. Therefore, the UE has no way of recognizing TRS / CSI-RS and DMRS, which is QCL, before the RRC connection is established.

[0010] Therefore, the following disclosure is made in light of these circumstances and aims to provide a terminal, wireless communication system, and wireless communication method that can achieve more accurate measurement of channel status even before RRC connection.

[0011] One aspect of the present disclosure is a terminal (UE200) comprising a receiving unit (control signal / reference signal processing unit 240) that receives a first downlink reference signal and a second downlink reference signal, and a control unit (control unit 270) that, when receiving the first downlink reference signal in a state where a connection at a specific layer has not been established, assumes that the first downlink reference signal is a pseudo-collocation with the second downlink reference signal.

[0012] One aspect of the present disclosure is a wireless communication system including a wireless base station and a terminal, wherein the wireless base station includes a transmitting unit that transmits a first downlink reference signal and a second downlink reference signal, and the terminal includes a receiving unit that receives the first downlink reference signal and the second downlink reference signal, and a control unit that, when receiving the first downlink reference signal in a state where a connection at a specific layer has not been established, assumes that the first downlink reference signal is a pseudo-collocation with the second downlink reference signal.

[0013] One aspect of the present disclosure is a wireless communication method comprising the steps of: a terminal receiving a first downlink reference signal and a second downlink reference signal; and, if the terminal receives the first downlink reference signal while a connection at a specific layer has not been established, assuming that the first downlink reference signal is a pseudo-collocation with the second downlink reference signal. [Brief explanation of the drawing]

[0014] [Figure 1]Figure 1 is a schematic diagram of the overall configuration of the wireless communication system 10. [Figure 2] Figure 2 shows an example of the configuration of wireless frames, subframes, and slots used in the wireless communication system 10. [Figure 3] Figure 3 shows an example of the TCI state field settings for DCI format 1_1 / 1_2. [Figure 4] Figure 4 shows the functional block diagrams of the gNB100 and UE200. [Figure 5] Figure 5 shows an example sequence of initial access procedures as defined by 3GPP Release 15, 16. [Figure 6] Figure 6 shows an example configuration of SSB and RACH Occasion (RO) / RAR windows (with beam correspondence). [Figure 7] Figure 7 shows an example configuration of SSB and RACH Occasion (RO) / RAR windows (regardless of beam correspondence). [Figure 8] Figure 8 shows an example of the beam determination process before RRC connection. [Figure 9] Figure 9 shows an example of beam determination operation after RRC connection. [Figure 10] Figure 10 shows an example of the DL-RS transmission sequence related to Operation Example 1. [Figure 11] Figure 11 shows an example of the beam determination operation related to Operation Example 2-1. [Figure 12] Figure 12 shows an example of the beam determination operation related to Operation Example 2-2. [Figure 13] Figure 13 shows an example of the beam determination operation related to Operation Example 3. [Figure 14] Figure 14 shows an example of the correspondence between SSB / TRS and MBS PDSCH / PDCCH Occasions related to Operation Example 3. [Figure 15] Figure 15 shows an example of the TCI state / QCL information instruction related to Operation Example 4. [Figure 16] FIG. 16 is a diagram showing an example of resource candidates according to Operation Example 4. [Figure 17] FIG. 17 is a diagram showing an example of the hardware configuration of gNB 100 and UE 200.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments will be described based on the drawings. Note that the same or similar reference numerals are assigned to the same functions and configurations, and the description thereof will be omitted as appropriate.

[0016] (1) Overall Schematic Configuration of Wireless Communication System (1.1) System Configuration Example FIG. 1 is an overall schematic configuration diagram of a wireless communication system 10 according to the present embodiment. The wireless communication system 10 is a wireless communication system according to 5G New Radio (NR), and includes a Next Generation-Radio Access Network 20 (hereinafter, NG-RAN 20) and a plurality of terminals 200 (User Equipment 200, hereinafter, UE 200).

[0017] <明 Note that the wireless communication system 10 may also be a wireless communication system according to a scheme called Beyond 5G, 5G Evolution, or 6G.

[0018] NG-RAN 20 includes a radio base station 100 (hereinafter, gNB 100). Note that the specific configuration of the wireless communication system 10 including the number of gNBs and UEs is not limited to the example shown in FIG. 1.

[0019] NG-RAN 20 actually includes a plurality of NG-RAN Nodes, specifically, gNBs (or ng-eNBs), and is connected to a 5G-compliant core network (5GC, not shown). Note that NG-RAN 20 and 5GC may simply be expressed as "network".

[0020] The gNB100 is a radio base station compliant with NR standards and performs NR-compliant wireless communication with the UE200. The gNB100 and UE200 can support Massive MIMO, which generates a more directional beamband by controlling radio signals transmitted from multiple antenna elements; carrier aggregation (CA), which uses multiple component carriers (CCs) bundled together; and dual connectivity (DC), which enables simultaneous communication between the UE and multiple NG-RAN nodes.

[0021] The wireless communication system 10 corresponds to FR1 and FR2. The frequency bands for each FR (Frequency Range) are as follows:

[0022] • FR1: 410 MHz ~ 7.125 GHz • FR2: 24.25 GHz ~ 52.6 GHz In FR1, a Sub-Carrier Spacing (SCS) of 15, 30, or 60 kHz may be used, and a bandwidth (BW) of 5 to 100 MHz may be used. FR2 is a higher frequency than FR1, and a 60 or 120 kHz (240 kHz may be included) SCS may be used, and a bandwidth (BW) of 50 to 400 MHz may be used.

[0023] Furthermore, the wireless communication system 10 may also support higher frequency bands than the FR2 frequency band. Specifically, the wireless communication system 10 may support frequency bands exceeding 52.6 GHz and up to 114.25 GHz. In addition, the wireless communication system 10 may support frequency bands between FR1 and FR2.

[0024] Alternatively, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) / Discrete Fourier Transform-Spread (DFT-S-OFDM) with a larger Sub-Carrier Spacing (SCS) may be applied. Furthermore, DFT-S-OFDM may be applied not only to the uplink (UL) but also to the downlink (DL).

[0025] Figure 2 shows an example of the configuration of wireless frames, subframes, and slots used in the wireless communication system 10.

[0026] As shown in Figure 2, one slot consists of 14 symbols, and the larger (wider) the SCS, the shorter the symbol duration (and slot duration). Note that the number of symbols constituting one slot does not necessarily have to be 14 (for example, 28 or 56 symbols). Also, the number of slots per subframe may differ depending on the SCS. Furthermore, the SCS may be wider than 240 kHz (for example, 480 kHz or 960 kHz, as shown in Figure 2).

[0027] The time direction (t) shown in Figure 2 may also be called the time domain, symbol period, or symbol time. The frequency direction may also be called the frequency domain, resource block, resource block group, subcarrier, BWP (Bandwidth part), subchannel, common frequency resource, etc.

[0028] (1.2) QCL / TCI state Quasi-colocation (QCL) is a method where, for example, if the characteristics of the channel carrying symbols on one antenna port can be inferred from the channel carrying symbols on the other antenna port, then the two antenna ports are considered to be in the same location.

[0029] Furthermore, it can be interpreted that QCLs are assumed to be between SSBs (Synchronization Signal / Physical Broadcast Channel blocks) with the same SSB index, while QCLs should not be assumed between other SSBs (i.e., those with different SSB indices). QCLs may also be called quasi-collocations.

[0030] For receiving PDSCH (Physical Downlink Shared Channel) or PDCCH (Physical Downlink Control Channel) (specifically the demodulation reference signal (DMRS)), the NR sets the TCI (Transmission Configuration Indication) state (if not set, the SSB index and QCL relationship from the most recent PRACH (Physical Random Access Channel) transmission may be used).

[0031] The TCI state may mean that it is explicitly set by a control element (MAC CE) of the Radio Resource Control Layer (RRC) or the Media Access Control Layer (MAC). The QCL relationship may include both cases where it is explicitly set by the TCI state and cases where the TCI state is not set. QCL / TCI state / beam may be interpreted as mutually interchangeable.

[0032] For example, when a PDCCH (Physical Downlink Control Channel) is described as being QCLed (quickly collocated) with SSB, it can be interpreted that the PDCCH passed through a channel state (channel condition) similar to that of SSB. In other words, when a PDCCH (or its DMRS) and SSB (and other RSs) are QCLed, it can be interpreted that both the PDCCH and SSB signals reached the receiver through fairly similar channel states. Therefore, channel estimation information used to detect SSB is also useful for detecting PDCCH.

[0033] Here, the channel state may be defined by the following parameters:

[0034] Doppler shift Doppler spread • Average delay • Delayed spread • Spatial Rx parameters Furthermore, QCL types may be defined using such parameters. Specifically, QCL types are defined in Chapter 5.1.5 of 3GPP TS38.214 as follows:

[0035] ·QCL-Type A: {Doppler shift, Doppler spread, average delay, delay spread} ·QCL-Type B: {Doppler shift, Doppler spread} ·QCL-Type C: {Doppler shift, average delay} ·QCL-Type D: {Spatial Rx parameter} For PDCCH / PDSCH DMRS, Type A must be set as the TCI state, and Type D may also be set (especially in the case of FR2).

[0036] Type A RS (CSI (Channel State Information)-RS) is used for long-term channel state measurement and can be used, for example, for channel estimation of DMRS. Measuring DMRS only provides instantaneous measurements, so Doppler information cannot be obtained. The UE200 obtains QCL-Type A (Doppler shift, Doppler spread, average delay, delay spread) information by measuring a periodic RS (e.g., TRS (Tracking Reference Signal)) that has been set as QCL Type A RS in advance, and uses this information to receive PDCCH / PDSCH.

[0037] Type D RS is used to notify the base station's transmitting spatial domain filter (essentially the analog beam). The UE200 measures the RS (e.g., TRS) that has been pre-configured as Type D RS to select the appropriate UE-side receiving spatial domain filter, and when PDCCH / PDSCH is received, it uses that receiving spatial domain filter to receive the PDCCH / PDSCH.

[0038] The TCI state of a PDSCH may be notified by the RRC and / or MAC CE. Up to eight TCI states of a PDSCH may be notified by the RRC / MAC CE and may be indicated by Downlink Control Information (DCI), specifically a TCI state field of up to 3 bits in DCI format 1_1 / 1_2 (present if the RRC's tciPresentInDCI is set).

[0039] If the time from DCI to PDSCH is shorter than timeDurationForQCL (details will be described later), the TCI state of PDSCH may be determined by a predetermined method. If DCI format is 1_1 / 1_2 and tciPresentInDCI is not set, there is no TCI state field, so the TCI state of PDSCH may be determined by a predetermined method.

[0040] Figure 3 shows an example of setting the TCI state field for DCI format 1_1 / 1_2. As shown in Figure 3, a 3-bit TCI state field may be assigned. The value of the TCI state field may be associated with a predetermined TCI state for a PDSCH.

[0041] In DCI format 1_0, there is no TCI state field, so the TCI state of the PDSCH may be determined by a predetermined method. This predetermined method may be called the Default TCI state.

[0042] In multicast PDSCH (MBS PDSCH) scheduling, the use of DCI format 1_0 is particularly expected.

[0043] Furthermore, the QCL of PDCCH(DCI) that scheduled PDSCH can be assumed to be the QCL of PDSCH.

[0044] (1.3) Provision by MBS The wireless communication system 10 may provide multicast and broadcast services (MBS).

[0045] For example, in stadiums and halls, it is conceivable that numerous UE200s are located within a certain geographical area and that many UE200s receive the same data simultaneously. In such cases, using MBS (Mobile-Based Broadcasting) is more effective than unicast.

[0046] Unicast can be interpreted as one-to-one communication between a specific UE200 (which may also be specified by its unique identifier) ​​and the network.

[0047] Multicast can be interpreted as communication between a network and multiple specific UE200 devices (multicast identification information may also be specified). Note that the number of UE200 devices receiving incoming multicast data may ultimately be just one.

[0048] Broadcasting can be interpreted as communication between the network and an unspecified number of devices, directed at all UE200s. Multicast / broadcast data may be identical copies, but some content, such as the header, may differ. Multicast / broadcast data may be transmitted (distributed) simultaneously, but strict simultaneity is not necessarily required, and propagation delays and / or processing delays within RAN nodes may be included.

[0049] The UE200 in question may have a Wireless Resource Control Layer (RRC) in any of the following states: idle, connected, or inactive. The inactive state can be interpreted as a state in which some RRC settings are maintained.

[0050] In MBS, three methods are envisioned for scheduling multicast / broadcast PDSCH, specifically for scheduling MBS packets (which can be interpreted as data). Note that RRC connected UE may be interpreted as RRC idle UE or RRC inactive UE.

[0051] ·PTM transmission method 1 (PTM-1): • For the MBS group of the RRC connected UE, schedule a group-common PDSCH using a group-common PDCCH.

[0052] The PDCCH's CRC (Cyclic Redundancy Checksum) and PDSCH are scrambled using the group-common RNTI (Radio Network Temporary Identifier).

[0053] ·PTM transmission method 2 (PTM-2): • For the MBS group of an RRC-connected UE, a group-common PDSCH is scheduled using a terminal-specific PDCCH.

[0054] • CRCs in PDCCH are scrambled using UE-specific RNTIs.

[0055] PDSCH is scrambled by group-common RNTI.

[0056] ·PTP transmission method: • For RRC-connected UEs, schedule UE-specific PDSCHs using UE-specific PDCCHs.

[0057] The CRC and PDSCH of PDCCH are scrambled by a UE-specific RNTI. This means that MBS packets are transmitted via unicast.

[0058] Furthermore, in order to improve the reliability of MBS, two feedback methods are envisioned for HARQ (Hybrid Automatic Repeat Request) feedback, specifically for HARQ feedback to multicast / broadcast PDSCH.

[0059] Option 1: Both ACK and NACK feedback (ACK / NACK feedback) • If the UE successfully receives and decodes the PDSCH signal, it sends an ACK. If the UE fails to receive and decode the PDSCH signal, it will send a NACK. • PUCCH (Physical Uplink Control Channel) resource settings: Allows you to configure PUCCH-Config for multicast. PUCCH Resources: Shared / orthogonal between UEs depends on the network settings. • HARQ-ACK CB (codebook): Supports type-1 and type-2 (CB decision algorithm (specified in 3GPP TS38.213)) • Multiplexing: Unicast or multicast can be applied. Option 2: NACK-only feedback A UE that successfully receives and decodes PDSCH does not send an ACK (no response). If the UE fails to receive and decode the PDSCH signal, it will send a NACK. • In a given UE, PUCCH resource settings can be configured separately via unicast or groupcast (multicast). Note that ACK may also be called a positive acknowledgement, and NACK may be called a negative acknowledgement. HARQ may also be called an automatic retransmission request.

[0060] Enabling or disabling Option 1 or Option 2 may be done by either of the following:

[0061] • RRC and Downlink Control Information (DCI) RRC only Furthermore, the following is envisioned for Semi-persistent Scheduling (SPS) of multicast / broadcast PDSCH.

[0062] • Uses SPS group-common PDSCH • As a UE capability, multiple SPS group-common PDSCHs can be configured. • HARQ feedback is available for SPS group-common PDSCH. • At least group-common PDCCH activation / deactivation is possible. Note that "deactivation" may be replaced with other synonymous terms such as "release." For example, "activation" may be replaced with "start," "start," or "trigger," and "deactivation" may be replaced with "end," "stop," or "stop."

[0063] SPS is a scheduling method used in contrast to dynamic scheduling, and may also be called semi-fixed, semi-persistent, or semi-permanent scheduling, and may be interpreted as Configured Scheduling (CS).

[0064] Scheduling can be interpreted as the process of allocating resources for transmitting data. Dynamic scheduling can be interpreted as a mechanism in which all PDSCHs are scheduled by DCI (e.g., DCI 1_0, DCI 1_1, or DCI 1_2). SPS can be interpreted as a mechanism in which PDSCH transmissions are scheduled by higher-layer signaling such as RRC messages.

[0065] Furthermore, regarding the physical layer, there may be scheduling categories for time-domain scheduling and frequency-domain scheduling.

[0066] Furthermore, multicast, groupcast, broadcast, and MBS may be interpreted interchangeably. Multicast PDSCH (which may include group-common PDSCH and SPS group-common PDSCH) and PDSCH scrambled by group-common RNTI (which may be called G-RNTI) may also be interpreted interchangeably.

[0067] Furthermore, the terms data and packet may be interpreted interchangeably and may be considered synonymous with terms such as signal and data unit. Also, transmission, reception, transmission, and distribution may be interpreted interchangeably.

[0068] (2) Functional block configuration of the wireless communication system Next, the functional block configuration of the wireless communication system 10 will be described. Specifically, the functional block configurations of gNB100 and UE200 will be described.

[0069] Figure 4 is a functional block diagram of the gNB100 and UE200. The UE200 will be described below. As shown in Figure 4, the UE200 comprises a wireless signal transmission / reception unit 210, an amplifier unit 220, a modulation / demodulation unit 230, a control signal / reference signal processing unit 240, an encoding / decoding unit 250, a data transmission / reception unit 260, and a control unit 270.

[0070] Note that Figure 4 only shows the main functional blocks relevant to the description of the embodiment, and the UE200 has other functional blocks (e.g., a power supply unit). Also, Figure 4 shows the functional block configuration of the UE200 (gNB100), but please refer to Figure 17 for the hardware configuration.

[0071] The wireless signal transceiver unit 210 transmits and receives wireless signals in accordance with NR. The wireless signal transceiver unit 210 supports Massive MIMO, CA which uses multiple CCs bundled together, and DC which communicates simultaneously between the UE and each of the two NG-RAN Nodes.

[0072] Furthermore, the wireless signal transceiver 210 is compatible with MBS and can receive downlink channels that are common to the terminal group when distributing data to multiple UE200s.

[0073] The wireless signal transceiver 210 can receive a common downlink data channel (PDSCH) for the terminal group, specifically a group-common PDSCH (which may include an SPS group-common PDSCH). The wireless signal transceiver 210 can also receive a common downlink control channel for the terminal group, specifically a group-common PDCCH.

[0074] The amplifier section 220 consists of components such as a PA (Power Amplifier) ​​and an LNA (Low Noise Amplifier). The amplifier section 220 amplifies the signal output from the modulation / demodulation section 230 to a predetermined power level. The amplifier section 220 also amplifies the RF signal output from the wireless signal transmission / reception section 210.

[0075] The modulation / demodulation unit 230 performs data modulation / demodulation, transmit power setting, and resource block allocation for each predetermined communication destination (such as gNB100). The modulation / demodulation unit 230 may apply Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) / Discrete Fourier Transform - Spread (DFT-S-OFDM). Furthermore, DFT-S-OFDM may be used not only for the uplink (UL) but also for the downlink (DL).

[0076] The control signal / reference signal processing unit 240 performs processing related to various control signals transmitted and received by the UE200, and processing related to various reference signals transmitted and received by the UE200.

[0077] Specifically, the control signal / reference signal processing unit 240 receives various control signals transmitted from the gNB100 via a predetermined control channel, such as control signals for the radio resource control layer (RRC). The control signal / reference signal processing unit 240 also transmits various control signals to the gNB100 via a predetermined control channel.

[0078] The control signal / reference signal processing unit 240 performs processing using reference signals (RS) such as Demodulation Reference Signal (DMRS), CSI-RS (Channel State Information-Reference Signal), and Tracking Reference Signal (TRS).

[0079] DMRS is a terminal-specific base station-to-terminal known reference signal (pilot signal) used to estimate the fading channel used for data demodulation. CSI-RS is a periodic reference signal used to estimate channel state information (CSI).

[0080] TRS is a periodic reference signal, similar to CSI-RS, and may correspond to NZP (Non-Zero Power) CSI-RS. In this embodiment, TRS may be interpreted as synonymous with CSI-RS, or they may be interchangeable.

[0081] Furthermore, the RS in the downlink (DL) direction may be called DL-RS. DL-RS may include at least one of DMRS (for PDSCH / PDCCH), CSI-RS, or TRS. In a broader sense, DL-RS may also include SSB.

[0082] The control signal / reference signal processing unit 240 may receive multiple such DL-RS signals. For example, the control signal / reference signal processing unit 240 may receive a first downlink reference signal (DL-RS #1) and a second downlink reference signal (DL-RS #2). In this embodiment, the control signal / reference signal processing unit 240 may constitute a receiving unit.

[0083] Furthermore, the control signal / reference signal processing unit 240 may receive more DL-RS signals than DL-RS #1 and DL-RS #2. The control signal / reference signal processing unit 240 may receive the DL-RS signals before the RRC connection is established (before RRC connection), or after the RRC connection is established (after RRC connection). Alternatively, the control signal / reference signal processing unit 240 may receive the DL-RS signals before or after the RRC connection is established.

[0084] The control signal / reference signal processing unit 240 may receive information indicating at least one of the DL-RS #1 and DL-RS #2 resources when a connection at a specific layer, such as RRC, has not been established. Specifically, the control signal / reference signal processing unit 240 may receive at least one of the DL-RS #1 and DL-RS #2 resource candidates. Reception of resource candidates may be achieved by RRC signaling or lower-layer signaling (e.g., DCI).

[0085] Resource candidates are radio resources (frequency, time, or space) that are candidates for DL-RS (e.g., TRS), and multiple candidates (e.g., 64) may be set / defined. Resource candidates may also be set / defined in correspondence with SSB.

[0086] Alternatively, the control signal / reference signal processing unit 240 may receive specific radio resources and / or QCL information, rather than resource candidates. For example, the control signal / reference signal processing unit 240 may receive information indicating a DL-RS (e.g., TRS) resource selected by the network (gNB100). The control signal / reference signal processing unit 240 may also receive DL-RS QCL information, such as TCI state or beam BM information (identification information, etc.).

[0087] Such QCL information may be included in system information broadcast from the network (gNB100). Specifically, QCL information may be included in the Master Information Block (MIB) and / or System Information Block (SIB). The control signal / reference signal processing unit 240 may receive system information that includes such QCL information.

[0088] In addition to the RS mentioned above, other terminal-specific reference signals such as the Phase Tracking Reference Signal (PTRS), Sounding Reference Signal (SRS), and Positioning Reference Signal (PRS) for location information may also be used as RS. These are intended for estimating phase noise, which is a problem in the high-frequency band.

[0089] Furthermore, channels include control channels and data channels. Control channels may include PDCCH, PUCCH (Physical Uplink Control Channel), RACH (Random Access Channel, Downlink Control Information (DCI) including Random Access Radio Network Temporary Identifier (RA-RNTI)), and Physical Broadcast Channel (PBCH), among others.

[0090] Data channels also include PDSCH and PUSCH (Physical Uplink Shared Channel). "Data" can refer to data transmitted through a data channel.

[0091] The encoding / decoding unit 250 performs data splitting / concatenation and channel coding / decoding for each predetermined communication destination (gNB100 or other gNB).

[0092] Specifically, the encoding / decoding unit 250 divides the data output from the data transmission / reception unit 260 into predetermined sizes and performs channel coding on the divided data. The encoding / decoding unit 250 also decodes the data output from the modulation / demodulation unit 230 and concatenates the decoded data.

[0093] The data transmission / reception unit 260 performs the transmission and reception of Protocol Data Units (PDUs) and Service Data Units (SDUs). Specifically, the data transmission / reception unit 260 performs assembly / decomposition of PDUs / SDUs at multiple layers (such as the Media Access Control Layer (MAC), Radio Link Control Layer (RLC), and Packet Data Convergence Protocol Layer (PDCP)). In addition, the data transmission / reception unit 260 performs error correction and retransmission control of data based on Hybrid ARQ (Hybrid automatic repeat request).

[0094] The control unit 270 controls each functional block that constitutes the UE200. In particular, in this embodiment, the control unit 270 performs control related to pseudo-collocation (QCL), such as the DL-RS reference signal and the synchronous signal block (SSB).

[0095] Specifically, the control unit 270 can perform control over QCLs for multiple types of DL-RS. As mentioned above, DL-RS may include DMRS (for PDSCH / PDCCH), CSI-RS, and TRS, and the control unit 270 may assume that these multiple types of DL-RS QCLs received at the same time are received according to predetermined conditions (criteria).

[0096] For example, the control unit 270 may perform such a QCL assumption when a connection has not been established at a specific layer, such as RRC. The state in which a connection has not been established at that layer may include the state before a connection is established (configured), or the state in which a connection has been established but is inactive except for some settings.

[0097] In the case of RRC, this may include the RRC idle state or the RRC inactive state. RRC inactive can be interpreted as a state where not all RRC settings are released, as in RRC idle, but some settings are maintained. Furthermore, it is not necessarily limited to RRC; the presence or absence of settings in other layers such as connections, channels, and bearers may also be used as a criterion.

[0098] When the control unit 270 receives a DL-RS, for example DL-RS #1 (first downlink reference signal), in a state where a connection at a specific layer has not been established, it may assume that DL-RS #1 is QCL with another DL-RS, for example DL-RS #2 (second downlink reference signal).

[0099] Here, DL-RS #1 can be, for example, a DMRS for PDSCH / PDCCH or a TRS / CSI-RS, and DL-RS #2 can be a DL-RS other than SSB (such as TRS / CSI-RS).

[0100] The control unit 270 may attempt to receive DL-RS #1 (or vice versa) using QCL information (such as the TCI state) obtained by measuring DL-RS #2.

[0101] Furthermore, the control unit 270 may also perform control related to the DL-RS QCL when distributing data to MBS, that is, to multiple UE200s.

[0102] For example, the control unit 270 may assume that in the MBS of the UE200 in the RRC idle state, the gNB100 repeatedly transmits multiple PDSCH / PDCCH signals. Specifically, the control unit 270 may assume that in multiple PDSCH / PDCCH occasions (transmission opportunities), the PDSCH / PDCCH signals are transmitted multiple times.

[0103] The gNB100 may transmit (notify) SSB and also transmit PDSCH / PDCCH for MBS (MBS PDSCH / PDCCH), but the UE200 only needs to recognize a TRS / CSI-RS (hereinafter abbreviated as TRS) resource that corresponds to a good quality SSB, so the UE200 only needs to be notified of at least one of the following:

[0104] (i) Correspondence between SSB / TRS and MBS PDSCH / PDCCH occasions (ii) A correspondence between any two of the following: SSB, TRS, and MBS PDSCH / PDCCH Note that " / " can be interpreted as meaning "or" (the same applies below).

[0105] The control unit 270 may, in this manner, configure the reception of the physical downlink channel (MBS PDSCH / PDCCH) in the MBS based on the correspondence between the physical downlink channel for the MBS and the synchronization signal block (SSB) or a specific downlink reference signal (TRS, etc.). More specific details regarding QCL-related operations in the MBS will be described later.

[0106] Furthermore, the gNB100 can perform control related to the transmission of DL-RS as described above. Specifically, the control signal / reference signal processing unit 240 of the gNB100 can transmit multiple DL-RS signals, for example, DL-RS #1 and DL-RS #2. The control signal / reference signal processing unit 240 of the gNB100 may constitute a transmission unit.

[0107] (3) Operation of the wireless communication system Next, the operation of the wireless communication system 10 will be described. Specifically, the operation of the QCL using TRS / CSI-RS before the RRC connection is established (before RRC connection) will be described.

[0108] (3.1) Premise (3.1.1) Initial Access Procedure Figure 5 shows an example sequence of an initial access procedure as defined by 3GPP Releases 15 and 16. Specifically, Figure 5 shows an example sequence following a so-called four-step random access (RA) procedure. A two-step RA procedure may also be applied.

[0109] As shown in Figure 5, messages 1 to 4 may be sent and received between gNB100 and UE200. UE200 may have received SSB and RMSI (Remaining Minimum System Information) before sending Msg.1 (PRACH).

[0110] RMSI may be interpreted as meaning System Information Block 1 (SIB1). RMSI may consist of system information that a device (UE200) needs to know before accessing the system. SIB1 may always be broadcast periodically throughout the cell. SIB1 can provide the information that UE200 needs to perform the initial random access (RA).

[0111] Once the gNB100 has finished sending Msg.2 (RA Response (RAR)) and Msg.4 (PDSCH), the RRC connection is established and the device enters the RRC connected state.

[0112] Figure 6 shows an example configuration of SSB and RACH Occasion (RO) / RAR windows (with beam correspondence). Figure 7 shows an example configuration of SSB and RACH Occasion (RO) / RAR windows (without beam correspondence).

[0113] As shown in Figure 6, UE200 may transmit Msg.1(PRACH) using a specific beam associated with the RO associated with the received SSB. This allows gNB100 to recognize the beam that UE200 can receive and transmit RAR using that beam.

[0114] Alternatively, as shown in Figure 7, UE200 may transmit Msg.1 using the received SSB and the corresponding beam, according to the PRACH format of multiple RACH OFDM symbols.

[0115] (3.1.2) Beam determination method (before RRC connection) Before RRC connection (which may include the RRC idle or RRC inactive state, and may also be called the RRC non-connected state), 3GPP TS38.214 and other standards specify that DMRS (for PDSCH / PDCCH, etc.) is SSB and QCL.

[0116] Figure 8 shows an example of beam determination operation before RRC connection. The UE200 can receive multiple SSBs and select the SSB with the highest received power (corresponding to the best beam). Here, the choice of which SSB to select is left to the implementation of the UE200 (i.e., it is not necessary to select the SSB with the highest received power).

[0117] UE200 may transmit PRACH in the PRACH Occasion corresponding to the "best" SSB. gNB100 can also recognize which SSB UE200 has determined to be the best (achieving a common beam understanding between UE and gNB).

[0118] The UE200 receives DMRS such as PDSCH / PDCCH, which are defined as SSB and QCL, using QCL information obtained from measuring the SSB with the highest received power. The gNB100 also transmits DMRS such as PDSCH / PDCCH using the same beam / QCL as the SSB that the UE200 has determined to be the best.

[0119] In other words, gNB100 does not instruct UE200 which beam to use; rather, UE200 makes the decision.

[0120] (3.1.3) Beam determination method (after RRC connection) After RRC connection (RRC connected state), when receiving DMRS such as PDSCH / PDCCH, it is stipulated that the TCI state instructed by RRC, MAC CE, or DCI should be followed.

[0121] Figure 9 shows an example of beam determination operation after RRC connection. When receiving SSB / TRS / CSI-RS signals, the UE200 measures RSRP (Reference Signal Received Power) and / or SINR (Signal-to-Interference plus Noise power Ratio) and reports the best (highest) beam to the gNB100 (L1-RSRP beam reporting).

[0122] Based on the report, gNB100 determines which beam to assign to UE200 and notifies UE200 of the TCI state. The selection of which beam to use is left to the implementation of gNB100. The UE200 uses the QCL information of the configured TCI state to transmit DMRS such as PDSCH / PDCCH. The gNB100 also uses the QCL information of the configured TCI state to transmit DMRS such as PDSCH / PDCCH.

[0123] In other words, the gNB100 instructs the UE200 which beam to use.

[0124] (3.1.4) Issues Regarding the above assumptions about QCL, if TRS / CSI-RS (hereinafter abbreviated as TRS as appropriate) can be used before RRC connection (for UEs in RRC idle or RRC inactive state), an improvement in the DMRS reception characteristics of the UE200 can be expected.

[0125] This is because TRSs with a higher resource element (RE) density and transmission bandwidth in the time / frequency domain can measure channel conditions more accurately.

[0126] Generally, both SSB and TRS are transmitted at the same frequency (e.g., 20 ms), although TRS can also be transmitted at a shorter frequency than SSB.

[0127] However, since the TCI state is determined by the RRC configuration at the earliest, it is not possible to receive (recognize) the DMRS, which is the TRS and QCL, before the RRC connection is established.

[0128] (3.2) Example of operation The following operational example describes how to solve the problems mentioned above, enable more accurate channel status measurement even before RRC connection, and improve the DL-RS receiving characteristics of the UE200, such as DMRS.

[0129] (3.2.1) Example of operation 1 In this example, before RRC connection is established (including RRC idle or RRC inactive states, the same applies hereafter), DL-RS #2 may be used as the QCL source when DL-RS #1 is received.

[0130] Figure 10 shows an example of the DL-RS transmission sequence related to Operation Example 1. As shown in Figure 10, the UE200 may repeatedly receive multiple types of DL-RS (DL-RS #1, #2) before RRC connection (in this case, RRC idle state).

[0131] When the UE200 receives DL-RS #1, it may use DL-RS #2 as the QCL source. In other words, it can be assumed that DL-RS #1 is QCLed with DL-RS #2.

[0132] Here, DL-RS #1 may include at least one DMRS such as PDSCH / PDCCH, or DL-RS such as TRS / CSI-RS. In particular, it is preferable that a DMRS such as PDSCH / PDCCH for UEs in the RRC idle or RRC inactive state be QCL with TRS, etc. DL-RS #2 may be any DL-RS other than SSB, for example, TRS / CSI-RS.

[0133] Furthermore, UE200 may receive DL-RS #1 using the QCL information obtained from the DL-RS #2 measurement.

[0134] (3.2.2) Example of operation 2 In this example, resource candidates for DL-RS #2 (e.g., TRS / CSI-RS), or specific resource / QCL information for DL-RS #2, may be notified to the UE200 from the network (gNB100).

[0135] (3.2.2.1) Example of operation 2-1 In this example, specific resource / QCL information for DL-RS #2 (e.g., TRS / CSI-RS) does not need to be notified.

[0136] Figure 11 shows an example of beam determination operation related to Operation Example 2-1. The gNB100 may notify the DL-RS #2 resource candidates (e.g., 64 types). For example, the gNB100 may notify the UE200 of multiple candidate TRS resources (e.g., 64), and the UE200 may select a TRS resource based on a predetermined method (or by the UE implementation).

[0137] TRS resources may include TRS / CSI-RS resources (such as time / frequency resources), as specified in 3GPP TS38.331, for example.

[0138] Furthermore, UE200 may notify gNB100 of information that identifies the selected TRS resource. For example, candidate TRS resources may correspond one-to-one with SSBs, and UE200 may notify gNB100 of the TRS resource it has selected by sending a PRACH on the PRACH occasion corresponding to the SSB.

[0139] (3.2.2.2) Example of operation 2-2 In this example, specific resource / QCL information from DL-RS #2 (e.g., TRS / CSI-RS) may be notified to the UE200 from the network (gNB100).

[0140] Figure 12 shows an example of beam determination operation related to Operation Example 2-2. The gNB100 may select a TRS resource and notify the UE200 of the selected TRS resource.

[0141] The TRS resources may include TRS / CSI-RS resources (such as time / frequency resources), as specified in example 2-1, for example, 3GPP TS38.331.

[0142] Furthermore, the information to be notified may be the QCL information of DL-RS #2 as the TCI state (in existing 3GPP regulations, the TRS / CSI-RS resource ID is set within the TCI state).

[0143] Alternatively, TRS / CSI-RS resources (such as time / frequency resources) may be notified not as TCI state, but for example, as "QCL RS information".

[0144] Furthermore, a beam report may refer to the transmission of PRACH as in Msg.1 (see Figure 5) (i.e., an implicit report). Alternatively, a new beam report may be defined and explicitly reported to the gNB100, for example, as part of Msg.3 using MAC CE or the like.

[0145] (3.2.3) Example of operation 3 This example concerns the assumption of QCL in MBS. 3GPP is considering the distribution of downlink data via MBS to UE200s in an RRC idle or RRC inactive state. In such an MBS, the assumption of QCL using TRS / CSI-RS may be applied to multiple UE200s before RRC connection, i.e., in an RRC idle or RRC inactive state.

[0146] Here, "before RRC connection" more precisely refers to (i) before PRACH transmission, or (ii) from PRACH transmission to completion of initial access (RA procedure), and may be limited to (i), or may include both (i) and (ii), or may be limited to (ii).

[0147] Figure 13 shows an example of beam determination operation related to Operation Example 3. For an MBS directed to a UE in the RRC idle state, the gNB100 may transmit (or repeatedly transmit) PDSCH / PDCCH during multiple PDSCH / PDCCH Occasions.

[0148] Furthermore, in the case of MBS, the gNB100 does not necessarily need to recognize the SSB / beam with good reception on the UE200.

[0149] The gNB100 may broadcast SSB and also broadcast PDSCH / PDCCH for MBS. In this case, only the UE200 needs to be aware of the TRS resource corresponding to the "good" SSB. Therefore, the UE200 only needs to be notified of at least one of the following:

[0150] (i) Correspondence between SSB / TRS and MBS PDSCH / PDCCH occasions (ii) A correspondence between any two of the following: SSB, TRS, and MBS PDSCH / PDCCH If (i) or (ii) is notified to the UE200, the TRS can be used as a QCL source even before the PRACH transmission in Operation Example 2-1.

[0151] The UE200 may determine the best SSB / TRS resource by measuring SSB / TRS and receive PDSCH / PDCCH for the MBS using that resource as QCL information.

[0152] The correspondence described in (i) or (ii) above may be communicated, for example, by system information (which may be an MBS-specific SIB) or as part of such system information (see Operation Example 4).

[0153] Furthermore, this correspondence may be communicated as part of the information communicated for PDSCH / PDCCH of an MBS for a UE in an RRC idle or RRC inactive state.

[0154] Figure 14 shows an example of the correspondence between SSB / TRS and MBS PDSCH / PDCCH Occasions related to Operation Example 3.

[0155] The SSB / TRS IDs corresponding to each MBS PDSCH / PDCCH Occasion shown in Figure 14 may be interpreted as either the QCL source corresponding to each MBS PDSCH / PDCCH Occasion or the TCI state corresponding to each MBS PDSCH / PDCCH Occasion.

[0156] In this case, the TCI state ID is notified, and the SSB / TRS ID that will be the QCL source within the TCI state may also be notified. The TRS may be a TRS used for receiving MTCH (Multicast Traffic Channel), or it may be a periodic TRS.

[0157] The UE200 may operate in the following order: SSB reception, SSB and QCL PDSCH (as described above, SIB (MCCH (Multicast Control Channel)) reception), and TRS-based PDSCH (MTCH) reception.

[0158] MTCH and MCCH may be interpreted as types of logical channels for MBS. Control information for MTCH reception may be transmitted via MCCH. If the control information for MCCH is changed, an MCCH change notification is sent (for example, by using an RNTI that scrambles the CRC of DCI, or by using a field included in DCI that schedules MCCH), and the UE200 can recognize the change in control information by receiving the MCCH change notification.

[0159] When UE200 receives an MTCH, it may choose not to use the information based on the TRS received before the MCCH change notification, but instead receive the MTCH based on the QCL with the TRS received after the MCCH change notification, or it may receive the MTCH assuming it is SSB and QCL. At the physical layer, it can be interpreted that the QCL is assumed in this way for the MBS PDSCH to which the MTCH is assigned and the PDCCH that schedules the MBS PDSCH.

[0160] Furthermore, the UE200 may perform such actions regardless of whether the TRS settings have been changed, or it may perform them only if the TRS settings have been changed.

[0161] The UE capability for TRS reception in MBS (e.g., MTCH) may be at least one of the following:

[0162] • Capability related to the usability of TRS • Capability related to TRS reception capability • The same capability exists between the RRC idle / inactive state and the RRC connected state. Furthermore, a UE200 that is capable of using or receiving TRS (which can be rephrased as supporting reception or reporting such capability) may receive MBS PDSCH / PDCCH (e.g., MTCH) based on TRS.

[0163] On the other hand, a UE200 that cannot use or receive TRS may receive an MBS PDSCH / PDCCH (e.g., MTCH) based on the SSB which is the QCL. Alternatively, the UE200 does not have to receive an MBS PDSCH / PDCCH. Such reception may be limited to cases where TRS-related information is notified by MCCH.

[0164] (3.2.4) Example of operation 4 In this example, TCI state / QCL information may be instructed to the UE200. Specifically, the TCI state / QCL information described in Example 2 may be instructed to the UE200 as follows.

[0165] Figure 15 shows an example of specifying TCI state / QCL information related to Operation Example 4. As shown in Figure 15, for MBS for UEs in the RRC idle or RRC inactive state, TCI state / QCL information may be specified by including it in the MIB / SIB (which may also be MBS specific).

[0166] Furthermore, the TCI state / QCL information may be included in Msg.2 (see Figure 5) or RAR UL grant (schedule information in Msg.3). Also, the correspondence between SSB / TRS and MBS PDSCH / PDCCH occasions, as explained in Operation Example 3, may be indicated to the UE200 using a similar mechanism.

[0167] Figure 16 shows an example of resource candidates related to Operation Example 4. The resource candidate information shown in Figure 16 may be communicated via broadcast information (or multicast / broadcast transmission to multiple UEs) to notify TRS / CSI-RS resource candidates, and one of the resource candidates may be selected based on individual UE information.

[0168] Specifically, as shown in Figure 16, individual UE resources may be specified from resource candidates by individual notifications to UE200 (for example, information such as "resource ID #1" may be notified to a specific UE200).

[0169] (4) Action and Effects According to the embodiment described above, the following effects can be obtained. Specifically, when UE200 receives a DL-RS, for example DL-RS #1 (first downlink reference signal), in a state where a connection at a specific layer such as RRC has not been established, it may be assumed that DL-RS #1 is QCL with another DL-RS, for example DL-RS #2 (second downlink reference signal).

[0170] Since DL-RS can include TRS / CSI-RS, the UE200 can achieve more accurate channel status measurements even before RRC connection. This is expected to improve the DL-RS, and especially the DMRS, reception characteristics of the UE200.

[0171] In this embodiment, the UE200 may receive information indicating at least one of the DL-RS #1 and DL-RS #2 resources even when a connection at a specific layer such as RRC has not been established. Therefore, even before an RRC connection is established, it is possible to measure the channel status more accurately based on this resource information.

[0172] In this embodiment, the UE200 may configure the reception of a physical downlink channel (MBS PDSCH / PDCCH) in the MBS based on the correspondence between the physical downlink channel for the MBS and a synchronization signal block (SSB) or a specific downlink reference signal (such as a TRS). Therefore, in the MBS, even before the RRC connection is established, more accurate channel status measurement can be achieved based on this correspondence.

[0173] In this embodiment, the UE200 may receive system information including QCL information. Therefore, even before RRC connection, it is possible to measure the channel status more accurately based on this system information.

[0174] (5) Other embodiments Although embodiments have been described above, it will be obvious to those skilled in the art that the invention is not limited to those embodiments described and that various modifications and improvements are possible.

[0175] For example, in the embodiment described above, terms such as DL-RS were used for the DL reference signal (RS), but other names for signals (control signals, pilot signals, etc.) may be used as long as they are signals in the DL direction and applicable to QCL assumptions.

[0176] Furthermore, while the above-described embodiment uses Operation Example 3 for MBS, this does not necessarily negate the applicability of the other operation examples to MBS. Moreover, the above-described operation examples may be combined and applied in combination, as long as no contradictions arise.

[0177] In the above description, configure, activate, update, indicate, enable, specify, and select may be interpreted as interchangeable. Similarly, link, associate, correspond, and map may be interpreted as interchangeable, and allocate, assign, monitor, and map may also be interpreted as interchangeable.

[0178] Furthermore, "specific," "dedicated," "UE specific," and "UE individual" may be interpreted interchangeably. Similarly, "common," "shared," "group-common," "UE common," and "UE shared" may be interpreted interchangeably.

[0179] In this disclosure, terms such as "precoding," "precoder," "weight (precoding weight)," "quasi-co-location (QCL)," "transmission configuration indication state (TCI state)," "spatial relation," "spatial domain filter," "transmit power," "phase rotation," "antenna port," "antenna port group," "layer," "number of layers," "rank," "resource," "resource set," "resource group," "beam," "beam width," "beam angle," "antenna," "antenna element," and "panel" may be used interchangeably.

[0180] Furthermore, the block diagram (Figure 4) used in the description of the embodiments above shows functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Moreover, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically coupled, or it may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired or wireless connections). A functional block may also be realized by combining the above one device or the above multiple devices with software.

[0181] Functions include, but are not limited to, judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, assumption, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), and assigning. For example, a functional block (configuration part) that enables transmission is called a transmitting unit or transmitter. In any case, as mentioned above, the method of implementation is not particularly limited.

[0182] Furthermore, the gNB100 and UE200 described above may function as computers that process the wireless communication method of this disclosure. Figure 17 shows an example of the hardware configuration of the device. As shown in Figure 17, the device may be configured as a computer device including a processor 1001, memory 1002, storage 1003, communication device 1004, input device 1005, output device 1006, and bus 1007.

[0183] In the following explanation, the term "device" can be replaced with "circuit," "device," "unit," etc. The hardware configuration of the device may include one or more of the devices shown in the diagram, or it may be configured to omit some of the devices.

[0184] Each functional block of the device (see Figure 4) is implemented by any hardware element of the computer device, or a combination of such hardware elements.

[0185] Furthermore, each function in the device is realized by loading predetermined software (programs) onto hardware such as the processor 1001 and memory 1002, which allows the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of data reading and writing in the memory 1002 and storage 1003.

[0186] The processor 1001 controls the entire computer, for example, by running an operating system. The processor 1001 may consist of a central processing unit (CPU) that includes interfaces with peripheral devices, control units, arithmetic units, registers, and so on.

[0187] Furthermore, the processor 1001 reads programs (program code), software modules, data, etc., from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes accordingly. The program used is one that causes the computer to execute at least a part of the operations described in the above embodiment. Moreover, the above-mentioned various processes may be executed by one processor 1001, or by two or more processors 1001 simultaneously or sequentially. The processor 1001 may be implemented by one or more chips. The program may be transmitted from a network via a telecommunications line.

[0188] Memory 1002 is a computer-readable recording medium and may consist of at least one of the following: Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), Random Access Memory (RAM), etc. Memory 1002 may also be called a register, cache, main memory, etc. Memory 1002 can store a program (program code), software modules, etc., that can execute a method according to one embodiment of this disclosure.

[0189] Storage 1003 is a computer-readable recording medium and may consist of at least one of the following: an optical disc such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disc, a digital multipurpose disc, a Blu-ray® disc), a smart card, flash memory (e.g., a card, a stick, a key drive), a floppy® disk, a magnetic strip, etc. Storage 1003 may also be called an auxiliary storage device. The recording medium described above may also be, for example, a database, server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0190] The communication device 1004 is hardware (transceiver / receiver device) for communicating between computers via at least one of a wired network and a wireless network, and is also called a network device, network controller, network card, communication module, etc.

[0191] The communication device 1004 may be configured to include, for example, a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD).

[0192] The input device 1005 is an input device that accepts input from an external source (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to an external source (e.g., a display, speaker, LED lamp, etc.). The input device 1005 and the output device 1006 may be configured as an integrated unit (e.g., a touch panel).

[0193] Furthermore, each device, such as the processor 1001 and the memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device.

[0194] Furthermore, the device may include hardware such as a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), and a field-programmable gate array (FPGA), and some or all of each functional block may be implemented by such hardware. For example, processor 1001 may be implemented using at least one of these hardware components.

[0195] Furthermore, notification of information is not limited to the embodiments / models described herein and may be carried out by other means. For example, notification of information may be carried out by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), upper layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or combinations thereof. RRC signaling may also be called RRC messages, and may be, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc.

[0196] Each aspect / embodiment described herein may be applied to at least one of the following: Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), Future Radio Access (FRA), New Radio (NR), W-CDMA®, GSM®, CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi®), IEEE 802.16 (WiMAX®), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth®, and other appropriate systems, as well as next-generation systems extended based thereon. Furthermore, multiple systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A with 5G).

[0197] The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described herein may be reordered, provided they are consistent with each other. For example, the methods described herein present various step elements in an exemplary order and are not limited to that specific order.

[0198] The specific operations described in this disclosure as being performed by a base station may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal can be performed by the base station and at least one other network node (for example, an MME or S-GW, but not limited to these). Although the above example illustrates the case where there is one other network node besides the base station, it may also be a combination of multiple other network nodes (for example, an MME and an S-GW).

[0199] Information and signals (such as data) can be output from a higher layer (or lower layer) to a lower layer (or higher layer). Input and output may occur via multiple network nodes.

[0200] Input and output information may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information may be overwritten, updated, or appended to. Output information may be deleted. Input information may be sent to other devices.

[0201] The determination may be made by a value represented by 1 bit (0 or 1), by a boolean value (true or false), or by a numerical comparison (for example, a comparison with a predetermined value).

[0202] Each aspect / embodiment described herein may be used individually, in combination, or switched between as needed during implementation. Furthermore, notification of specific information (e.g., notification that "X is") is not limited to explicit notification, but may also be implicit (e.g., by not providing such notification).

[0203] Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on, whether they are called software, firmware, middleware, microcode, hardware description languages, or by any other name.

[0204] Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technology (such as coaxial cable, fiber optic cable, twisted pair, or Digital Subscriber Line (DSL)) and wireless technology (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium.

[0205] The information, signals, etc. described in this disclosure may be represented using any of the various different technologies. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0206] In addition, terms used in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of the channel and symbol may be a signal (signaling). Also, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, cell, frequency carrier, etc.

[0207] The terms “system” and “network” as used in this disclosure are interchangeable.

[0208] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or other corresponding information. For example, wireless resources may be indicated by an index.

[0209] The names used for the parameters described above are not restrictive in any way. Furthermore, the formulas and other expressions using these parameters may differ from those expressly disclosed in this disclosure. Since various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, the various names assigned to these various channels and information elements are not restrictive in any way.

[0210] In this disclosure, terms such as "Base Station (BS)," "wireless base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0211] A base station can house one or more (e.g., three) cells (also called sectors). If a base station houses multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, each of which can also be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0212] The terms "cell" or "sector" refer to a portion or all of the coverage area of ​​at least one of the base stations and base station subsystems that provide communication services in this coverage.

[0213] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0214] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other appropriate term.

[0215] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile body, the mobile body itself, etc. The mobile body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may be a device that does not necessarily move during communication operation. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0216] Furthermore, the term "base station" in this disclosure may be interpreted as "mobile station" (user terminal, hereinafter the same). For example, the various aspects / embodiments of this disclosure may be applied to a configuration in which communication between a base station and a mobile station is replaced with communication between multiple mobile stations (which may be called, for example, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.). In this case, the mobile station may have the functions that a base station has. Also, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, uplink channel, downlink channel, etc. may be interpreted as side channel (or side link).

[0217] Similarly, the term "mobile station" in this disclosure may be interpreted as "base station." In this case, the base station may be configured to have the functions that a mobile station has. A wireless frame may consist of one or more frames in the time domain. Each of these one or more frames in the time domain may be called a subframe. A subframe may further consist of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0218] Numerology may be communication parameters applied to at least one of the transmission and reception of a signal or channel. Numerology may include, for example, at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame configuration, specific filtering processes performed by the transceiver in the frequency domain, and specific windowing processes performed by the transceiver in the time domain.

[0219] A slot may consist of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol). A slot may also be a time unit based on neurology.

[0220] A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. Minislots may also be called subslots. Minislots may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called a PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called a PDSCH (or PUSCH) mapping type B.

[0221] Wireless frames, subframes, slots, minislots, and symbols all represent units of time when transmitting a signal. Different names may be used for each of these terms.

[0222] For example, one subframe may be called a Transmit Time Interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. In other words, at least one of a subframe and a TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0223] Here, TTI refers to, for example, the smallest unit of time for scheduling in wireless communication. For example, in an LTE system, the base station schedules each user terminal to allocate wireless resources (such as the frequency bandwidth and transmission power available to each user terminal) in TTI units. However, the definition of TTI is not limited to this.

[0224] TTI may be a transmission time unit for channel-encoded data packets (transport blocks), code blocks, code words, etc., or it may be a processing unit for scheduling, link adaptation, etc. Given a TTI, the actual time interval (e.g., number of symbols) to which the transport block, code block, code word, etc. are mapped may be shorter than the given TTI.

[0225] Furthermore, if one slot or one mini-slot is referred to as TTI, then one or more TTIs (i.e., one or more slots or one or more mini-slots) may constitute the minimum time unit of scheduling. In addition, the number of slots (number of mini-slots) that constitute this minimum time unit of scheduling may be controlled.

[0226] A TTI with a time length of 1ms may also be called a normal TTI, long TTI, normal subframe, long subframe, slot, etc. A TTI shorter than a normal TTI may also be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, mini slot, sub slot, slot, etc.

[0227] Furthermore, long TTIs (e.g., normal TTIs, subframes, etc.) may be interpreted as TTIs with a time length exceeding 1 ms, and short TTIs (e.g., shortened TTIs, etc.) may be interpreted as TTIs with a TTI length less than that of a long TTI but 1 ms or more.

[0228] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and in the frequency domain, it may contain one or more consecutive subcarriers. The number of subcarriers in an RB may be the same regardless of the neurology, for example, 12. The number of subcarriers in an RB may be determined based on the neurology.

[0229] Furthermore, the time domain of the RB may contain one or more symbols and may be the length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc., may each consist of one or more resource blocks.

[0230] One or more RBs may also be called a Physical RB (PRB), Sub-Carrier Group (SCG), Resource Element Group (REG), PRB pair, RB pair, etc.

[0231] Furthermore, a resource block may consist of one or more resource elements (REs). For example, one RE may be a radio resource area comprising one subcarrier and one symbol.

[0232] A Bandwidth Part (BWP), also known as a partial bandwidth, may represent a subset of consecutive common resource blocks (RBs) for a given neurology on a given carrier. Here, the common RBs may be identified by an index of the RBs relative to the carrier's common reference point. PRBs may be defined and numbered within a BWP.

[0233] A BWP may include BWPs for UL (UL BWP) and BWPs for DL ​​(DL BWP). One or more BWPs may be set within a single carrier for a UE.

[0234] At least one of the configured BWPs may be active, and the UE does not need to assume that it will send or receive a given signal / channel outside of the active BWP. In this disclosure, terms such as "cell" and "carrier" may be read as "BWP".

[0235] The structures described above, such as wireless frames, subframes, slots, minislots, and symbols, are merely illustrative. For example, the number of subframes included in a wireless frame, the number of slots per subframe or wireless frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, and the number of symbols, symbol length, and cyclic prefix (CP) length within the TTI can be varied in various ways.

[0236] The terms “connected,” “coupled,” or any variation thereof, mean any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are “connected” or “coupled” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be reinterpreted as “access.” As used in this disclosure, two elements may be considered to be “connected” or “coupled” with each other using at least one of one or more wires, cables, and printed electrical connections, and, in some non-limiting and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain.

[0237] The reference signal can also be abbreviated as Reference Signal (RS), and may be called a pilot depending on the applicable standard.

[0238] In this disclosure, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on."

[0239] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0240] Any reference to elements using designations such as “First,” “Second,” etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Accordingly, references to the First and Second elements do not imply that only two elements may be employed therein, or that the First element must precede the Second element in any way.

[0241] Where the terms “include,” “including,” and variations thereof are used in this disclosure, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to mean exclusive OR.

[0242] In this disclosure, if articles are added through translation, such as a, an, and the in English, this disclosure may include the fact that the noun following these articles is plural.

[0243] As used in this disclosure, the terms “determining” and “determining” may encompass a wide variety of actions. “Determining” may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiry (e.g., searching in a table, database, or other data structure), and ascertaining. “Determining” may also include, for example, receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, and accessing (e.g., accessing data in memory). Furthermore, "judgment" and "decision" can include considering something as having been "judged" or "decided" after resolving, selecting, choosing, establishing, comparing, etc. In other words, "judgment" and "decision" can include considering something as having been "judged" or "decided" after some action. Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering."

[0244] In this disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "combine" may be interpreted similarly to "different."

[0245] Although the present disclosure has been described in detail above, it will be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure may be implemented in modified and altered forms without departing from the intent and scope of the present disclosure as defined by the claims. Accordingly, the descriptions in the present disclosure are for illustrative purposes only and are not intended to be restrictive in any way. [Explanation of symbols]

[0246] 10 Wireless communication systems 20 NG-RAN 100 gNB 200 UE 210 Wireless signal transmission and reception unit 220 Amplifier section 230 Modulation / Demodulation Section 240 Control signal / reference signal processing unit 250 Encoding / Decoding Unit 260 Data transmission / reception unit 270 Control Unit 1001 Processor 1002 memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus

Claims

1. A receiving unit that receives system information including pseudo-collocation information of a TRS, which is a periodic downlink reference signal, and information indicating the resource of the TRS, A terminal comprising a control unit that determines the pseudo-collocation of the TRS when a multicast PDSCH is scheduled while a connection at the RRC layer has not been established.

2. The terminal according to claim 1, wherein the control unit assumes that the PDSCH is a synchronization signal block and a QCL, and receives the PDSCH.

3. The terminal according to claim 1, wherein the UE capability related to TRS reception is the same in the state where the connection at the RRC layer is not established and in the RRC connected state.

4. The terminal according to claim 1, wherein the receiving unit receives system information including the correspondence between the transmission opportunity of the multicast PDSCH and the synchronization signal block.

5. The terminal according to claim 1, which, in the state in which a connection at the RRC layer has not been established, repeatedly receives a PDCCH that schedules the multicast PDSCH.

6. The system receives system information including pseudo-collocation information of a TRS, which is a periodic downlink reference signal, and information indicating the resources of the TRS. A terminal communication method for determining pseudo-collocation of a TRS when a multicast PDSCH is scheduled while a connection at the RRC layer has not been established.

7. A wireless communication system including a wireless base station and a terminal, The aforementioned wireless base station is The system includes a transmission unit that transmits system information including pseudo-collocation information of a TRS, which is a periodic downlink reference signal, and information indicating the resources of the TRS. The aforementioned terminal is A receiving unit that receives the aforementioned system information, A wireless communication system comprising a control unit that determines the pseudo-collocation of the TRS when a multicast PDSCH is scheduled while a connection at the RRC layer has not been established.

8. A control unit that schedules multicast PDSCHs for multiple terminals, The system includes a transmission unit that transmits system information including pseudo-collocation information of a TRS, which is a periodic downlink reference signal, and information indicating the resources of the TRS. A wireless base station that causes the terminal, in a state where a connection at the RRC layer has not been established, to determine the pseudo-collocation of the TRS.

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