Terminal

Abstract

This terminal comprises: a reception unit that receives, from a base station, an instruction to perform a transition of lower layer control to a distributed device of the base station or another base station; and a control unit that, in response to the instruction, performs communication with the distributed device or the other base station by bundling a first carrier, which provides a first cell for which a connection is first established during the transition, with a second carrier that provides a second cell other than the first cell. The reception unit receives the instruction, which includes first setting information related to the first cell and second setting information related to the second cell.

Description

Terminal

[0001] The present disclosure relates to a terminal that supports Lower layer Triggered Mobility (LTM).

[0002] The 3rd Generation Partnership Project (3GPP (registered trademark)) 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 mobile communication system called Beyond 5G, 5G Evolution or 6G.

[0003] In 3GPP Release 19, an extension of Lower layer Triggered Mobility (LTM) that triggers handover (HO) to transition a terminal to another cell in the lower layer (L1 / L2) has been discussed (Non-Patent Document 1).

[0004] “New WID: NR mobility enhancements Phase 4”, RP-234036, 3GPP TSG RAN Meeting #102, 3GPP, December 11-15, 2023

[0005] By the way, as a technology to improve throughput, carrier aggregation (CA) that communicates by integrating multiple cells is known. However, how to implement LTM when a terminal executes CA has not been sufficiently studied.

[0006] Therefore, an object of the present disclosure is to provide a terminal that can implement LTM suitable for CA. Note that the technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those having ordinary knowledge in the technical field to which the present disclosure belongs from the description of this specification.

[0007] One aspect of the disclosure is a terminal comprising: a receiving unit (radio signal transmitting / receiving unit 210) that receives instructions from a base station to perform a transition of lower-layer control to a distributed device of the base station or another base station; and a control unit (control unit 270) that, in response to the instructions, communicates with a first carrier that provides a first cell with which a connection is first established in the transition, and a second carrier that provides a second cell other than the first cell, wherein the receiving unit receives the instructions which include first setting information relating to the first cell and second setting information relating to the second cell.

[0008] Figure 1 is an overall schematic diagram of the wireless communication system. Figure 2 is a diagram showing the frequency range used in the wireless communication system. Figure 3 is a diagram showing an example of the configuration of wireless frames, subframes, slots, and symbols used in the wireless communication system. Figure 4 is a functional block diagram of a terminal. Figure 5 is a functional block diagram of a base station. Figure 6 is a diagram showing an example of MAC CE including configuration information related to SCell. Figure 7 is a diagram showing part of the sequence of Intra-CU LTM. Figure 8 is a diagram showing part of the sequence of Inter-CU LTM. Figure 9 is a diagram showing part of the sequence of NG LTM. Figure 10 is a diagram showing an example of the hardware configuration of a base station and a terminal. Figure 11 is a diagram showing an example of the configuration of a vehicle.

[0009] The embodiments will be described below with reference to the drawings. Note that identical or similar reference numerals are used to denote the same functions and components, and their descriptions will be omitted as appropriate.

[0010] (1) Wireless communication system configuration The wireless communication system 10 shown in Diagram 1 is a wireless communication system that follows a method called 5G. On the other hand, wireless communication system 10 may also be a wireless communication system that follows a method called Beyond 5G, 5G Evolution, or 6G.

[0011] The wireless communication system 10 can support Massive Multiple-Input Multiple-Output (Massive MIMO), which generates a more directional beam by controlling the wireless 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 with two base stations.

[0012] As shown in Figure 1, the wireless communication system 10 includes a base station (hereinafter also referred to as gNB) 100 that constitutes the Next Generation-Radio Access Network (NG-RAN) 20, and a terminal (hereinafter also referred to as user equipment (UE)) 200 that communicates wirelessly with the gNB 100. NG-RAN 20 may be read as gNB 100.

[0013] NG-RAN20 is connected to the core network (CN) 30. CN30 consists of multiple network functions (NFs). These NFs include, for example, the Access and Mobility Management Function (AMF) 300 and the Network Data Analytics Function (NWDAF) 400. The AMF 300 registers the UE200 and manages the mobility of the UE200. The NWDAF 400 optimizes CN30. Note that the specific configuration of the wireless communication system 10, such as the number of gNB100s and UE200s, is not limited to the example shown in Figure 1. Furthermore, NG-RAN20 and CN30 may simply be referred to as the "network (NW)".

[0014] The gNB100 may consist of distributed units (DUs) that form cells to which the UE200 is connected, and a central unit (CU) that controls the DUs. The CU may consist of a CU-CP that controls the control plane (CP) and a CU-UP that controls the user plane (UP). In other words, the gNB100 may consist of DUs, CU-CPs, and CU-UPs.

[0015] The gNB100 in this embodiment can perform a handover (HO) to transfer the UE200 to another cell. The gNB100 can also perform Lower Layer Triggered Mobility (LTM), which triggers HO at a lower layer. The lower layer may refer to L1 or L2. That is, the lower layer may be understood as a layer lower than the conventional L3 (RRC layer) that controls HO.

[0016] HO may be a conditional HO in which UE200 autonomously executes a transition based on pre-set conditions (events). Similarly, LTM may be a conditional LTM in which UE200 autonomously executes a transition based on pre-set conditions (events).

[0017] LTM may be interpreted as a change in the cell (or beam) to which the UE200 is connected. Alternatively, LTM may be interpreted as control by the gNB100 to change the cell (or beam) to which the UE200 is connected.

[0018] During LTM execution, the UE200 measures cell quality and sends the measurement results to the gNB100 as a measurement report. Based on these measurement results, configuration information, including information about the target cell to which the UE200 will transition, is sent and received between DUs controlled by the same gNB100 or between different gNB100s, and then configured in the UE200. This sequence will be described in detail in the operation example.

[0019] LTM may refer to the entire LTM sequence or to a part of the LTM sequence. For example, LTM may refer to the gNB100 setting the target cell to which UE200 will transition after receiving an L3 measurement report from UE200. Alternatively, LTM may refer to the gNB100 sending a cell switch command to UE200 after receiving an L1 measurement report from UE200.

[0020] An LTM that transitions the UE200 between multiple DUs (cells formed by them) controlled by the same gNB100 (CU) may be called an Intra-CU LTM. Similarly, an LTM that transitions the UE200 between different gNB100s (cells controlled by them) may be called an Inter-CU LTM. An Inter-CU LTM may also be called an NG LTM if the gNB100s are not connected via an Xn interface.

[0021] As shown in Figure 2, the wireless communication system 10 may support multiple frequency ranges (FRs). Specifically, it may support the following FRs: • FR1: 410 MHz to 7.125 GHz • FR2-1: 24.25 GHz to 52.6 GHz • FR2-2: Over 52.6 GHz to 71 GHz

[0022] In FR1, a subcarrier spacing (SCS) of 15, 30, or 60 kHz and a bandwidth (BW) of 5 to 100 MHz may be used. In FR2-1, an SCS of 60 or 120 kHz (or 240 kHz) and a BW of 50 to 400 MHz may be used.

[0023] In FR2-2, to avoid an increase in phase noise, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) or Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) with a larger SCS may be used.

[0024] As shown in Figure 3, one slot in the wireless communication system 10 consists of 14 symbols. If this configuration is maintained, the larger (wider) the SCS becomes, the shorter the symbol period (and slot period). Note that the SCS is not limited to the frequencies shown in Figure 3, and may be other frequencies such as 480 kHz or 960 kHz.

[0025] Furthermore, the number of symbols constituting one slot does not necessarily have to be 14; for example, it could be 28 or 56 symbols. In addition, the number of slots per subframe may vary depending on the SCS.

[0026] (2) Functional block configuration of the wireless communication system (2.1) Functional block configuration of the terminal 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.

[0027] The wireless signal transceiver 210 transmits and receives wireless signals to and from the gNB 100. The wireless signal transceiver 210 may consist of a transmitting unit that transmits wireless signals to the gNB 100 and a receiving unit that receives wireless signals from the gNB 100. The wireless signals may include control signals (reference signals) or data, or may be interpreted as control signals (reference signals) or data. Transmission may be interpreted as reporting, notification, etc. Reception may be interpreted as setting, instructing, notification, etc. Setting may be implemented by setting information (information elements (IE)) of the radio resource control (RRC) layer. Instructions may be implemented by control elements (CE) of the media access control (MAC) layer, or by downlink control information (DCI).

[0028] The wireless signal transceiver 210 of this embodiment can receive an instruction from the source gNB100 (gNB100A) of the UE200 to perform a lower-layer control transition to a Target DU or other gNB100 (gNB100B) controlled by gNB100A. Note that the source gNB100A may be read as the Source DU controlled by gNB100A. Furthermore, the instruction to perform a lower-layer control transition may be understood as an instruction to perform an LTM, and may be understood as corresponding to (including) the cell switch command in the operation example. Note that in this disclosure, the terms "source / destination" may mean "the cell formed by the source / destination DU or gNB100".

[0029] An instruction to perform a transition in lower-layer control may include setting information for the primary cell (PCell) and setting information for the secondary cell (SCell). That is, the wireless signal transmission / reception unit 210 of the embodiment can receive an instruction to perform a transition in lower-layer control that includes setting information for PCell and setting information for SCell. PCell may be referred to as the first cell and SCell as the second cell.

[0030] In this disclosure, the phrase "PCell configuration information" may mean an LTM candidate config that configures information about the PCell that will be the target cell via an RRC message. The phrase "PCell configuration information" may also mean a Target config ID that, via the MAC CE shown in Figure 6, causes the cell switch to apply the contents of the LTM candidate config, specifically the contents related to the PCell, to the UE200. Furthermore, the phrase "PCell configuration information" may also mean an ID that identifies the PCell.

[0031] In this disclosure, the phrase "SCell configuration information" may mean the SCell config, which configures information about the target cell SCell via an RRC message. The SCell config may or may not be included in the LTM candidate config described above. Furthermore, the phrase "SCell configuration information" may mean the SCell config ID, which causes the cell switch to apply the contents of the SCell config to the UE200 via the MAC CE shown in Figure 6. Furthermore, the phrase "SCell configuration information" may mean the ID that identifies the SCell (SCell ID).

[0032] Furthermore, the phrase "SCell configuration information" may refer to SCell config info transmitted or received within or between gNB100 units. SCell config info may include SCell status and SCell beam status in addition to the SCell config ID and SCell config mentioned above. SCell status and SCell beam status indicate whether the SCell / SCell beam is active or inactive.

[0033] Instructions for transitioning lower-layer control may be understood as instructions in RACH-less LTM, and may be understood as corresponding to (including) the PDCCH order in the example operation.

[0034] The wireless signal transmission / reception unit 210 of this embodiment may receive instructions to perform a transition of lower-layer control via the control element (MAC CE) of the media access control layer.

[0035] The wireless signal transceiver 210 of the embodiment may transmit the cell quality of the SCell to the gNB100. The cell quality may be, for example, the Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), or Signal to Interference plus Noise Ratio (SINR) of the synchronization signal or reference signal. The synchronization signal may be an SS / PBCH block (SSB). The reference signal may be a channel status information reference signal (CSI-RS). The cell quality may be transmitted as a measurement report. The measurement report may be understood to correspond to the L3 / L1 measurement reporting in the operating example.

[0036] The wireless signal transmission / reception unit 210 of this embodiment may receive setting information including a first condition relating to the cell quality of PCell and the cell quality of SCell, and a second condition relating only to the cell quality of SCell. The first and second conditions may be understood to correspond to the two LTM execution conditions described in the operation example. This setting information may also be set from gNB100 via the RRC layer.

[0037] The amplifier section 220 consists of a Power Amplifier (PA) and a Low Noise Amplifier (LNA), among other components. The amplifier section 220 amplifies the wireless signal output from the wireless signal transmission / reception unit 210. The amplifier section 220 also amplifies the wireless signal output from the modulation / demodulation unit 230.

[0038] The modulation / demodulation unit 230 performs data modulation / demodulation, transmit power setting, and resource block allocation for each predetermined communication destination (gNB100 or other gNB100). CP-OFDM / DFT-S-OFDM may be applied in the modulation / demodulation unit 230. Furthermore, DFT-S-OFDM may be used not only for the uplink (UL) but also for the downlink (DL).

[0039] The control signal / reference signal processing unit 240 performs processing related to control signals transmitted to and from the gNB100, such as radio resource control (RRC) signaling.

[0040] The control signal / reference signal processing unit 240 performs processing on reference signals transmitted to and from the gNB100, such as the Demodulation Reference Signal (DMRS), Phase Tracking Reference Signal (PTRS), Channel State Information-Reference Signal (CSI-RS), Sounding Reference Signal (SRS), and Positioning Reference Signal (PRS).

[0041] Note that the channels include a control channel and a data channel. The control channel includes a Physical Uplink Control Channel (PUCCH), a Physical Downlink Control Channel (PDCCH), a Physical Random Access Channel (PRACH), a Physical Broadcast Channel (PBCH), etc. The data channel includes a Physical Uplink Shared Channel (PUSCH), a Physical Downlink Shared Channel (PDSCH), etc.

[0042] The encoding / decoding unit 250 performs operations such as segmentation / concatenation and coding / decoding of data included in a radio signal for each predetermined communication destination (gNB100 or another gNB100).

[0043] Specifically, the encoding / decoding unit 250 decodes the data output from the modulation / demodulation unit 230 and concatenates the decoded data. Also, the encoding / decoding unit 250 segments the data output from the data transceiver unit 260 into a predetermined size and performs coding on the segmented data.

[0044] The data transceiver unit 260 performs operations such as assembly / disassembly of data units (Protocol Data Unit (PDU) / Service Data Unit (SDU)) that constitute data between each layer. The plurality of layers include a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, a Packet Data Convergence Protocol (PDCP) layer, etc. Also, the data transceiver unit 260 performs error correction and retransmission control of data based on Hybrid Automatic Repeat Request (HARQ).

[0045] The control unit 270 controls the UE200. The control unit 270 controls, for example, the transmission and reception of radio signals by the radio signal transceiver unit 210, the amplification by the amplifier unit 220, the data modulation / demodulation by the modulation / demodulation unit 230, the signal processing by the control signal / reference signal processing unit 240, the coding / decoding by the encoding / decoding unit 250, and the assembly / disassembly of data units by the data transceiver unit 260.

[0046] The control unit 270 of the embodiment can transition to a PCell and an SCell formed by the Target DU or gNB100B, which is the destination of the UE200, in response to an instruction to perform a transition of the lower layer control described above. A PCell may be understood as, for example, the cell to which the connection is first established with the gNB100 or the cell to which the RRC connection is set. An SCell may be understood as a cell other than a PCell in a cell group that includes multiple cells. Note that there may be one SCell or two or more SCells. Furthermore, the control unit 270 of the embodiment can communicate with a first carrier that provides a PCell and a second carrier that provides an SCell in a bundle at the destination. The first carrier may be called a Primary Component Carrier (PCC). The second carrier may be called a Secondary Component Carrier (SCC). Communicating with a first carrier that provides a first cell and a second carrier that provides a second cell in a bundle can be rephrased as simply performing carrier aggregation (CA) between the first cell and one or more second cells.

[0047] In other words, the control unit 270 of the embodiment can communicate with the Target DU or gNB100B, the destination of the UE200, by bundling together a PCC that provides the PCell that is first connected in the transition of lower layer control, and an SCC that provides SCells other than PCells. This communication bundling multiple CCs may be called a CA. CA may be understood as a technique that improves throughput by allowing the UE200 to connect not only to PCells but also to SCells.

[0048] The control unit 270 of the embodiment may omit the initial access procedure in the transition of the above-described lower layer control. The transition of the lower layer control that omits the initial access procedure may be understood to correspond to RACH-less LTM in the operation example. In this case, the timing advance (TA) values of the PCell and SCell may be transmitted from the target DU or gNB100B of the transition destination to the gNB100A of the transition source. Note that the gNB100A of the transition source may be understood to be the CU of the gNB100A.

[0049] The control unit 270 of the embodiment may bundle and communicate the PCC that provides the PCell and the SCC that provides the SCell other than the PCell when both the above-described first condition and the second condition are satisfied.

[0050] As shown in the functional block diagram of the terminal in (2.2), FIG. 5, the gNB100 includes a radio signal transceiver unit 110 and a control unit 120.

[0051] The gNB100 of the embodiment may be reconfigured as the source base station (gNB) 100A that controls the cell of the transition source of the UE200 or the target base station (gNB) 100B that controls the cell of the transition destination of the UE200 in the above-described HO or LTM. Note that HO may be understood as a higher concept of LTM.

[0052] The gNB100 of the embodiment can transmit and receive the information described in the operation example between the DU and CU that constitute the gNB100. Also, the gNB100 of the embodiment can transmit and receive the information described in the operation example with other gNB100s.

[0053] The wireless signal transceiver 110 transmits and receives wireless signals to and from the UE 200. The wireless signal transceiver 110 may consist of a transmitting unit that transmits wireless signals to the UE 200 and a receiving unit that receives wireless signals from the UE 200. The wireless signals may include control signals (reference signals) or data, or may be interpreted as control signals (reference signals) or data. Transmission may be interpreted as setting, instruction, notification, etc. Reception may be interpreted as reporting, notification, etc. Setting may be implemented by setting information (information elements (IE)) of the Radio Resource Control (RRC) layer, and instruction may be implemented by control elements (CE) or downlink control information (DCI) of the Media Access Control (MAC) layer.

[0054] Furthermore, the wireless signal transmission / reception unit 110 can transmit and receive information as described in the operation example.

[0055] The control unit 120 controls the gNB100. The control unit 120 controls, for example, the transmission and reception of wireless signals by the wireless signal transmission / reception unit 110. The control unit 120 also anticipates the operation of the UE200. The control unit 120 can control the gNB100 by anticipating the operation of the UE200.

[0056] The control unit 120 of this embodiment can execute transitions of the UE200 between cells controlled by the gNB100. That is, the control unit 120 of this embodiment can execute HO and LTM. Note that HO and LTM may be reinterpreted as terms such as cell transition, cell change, and beam change.

[0057] The control unit 120 of this embodiment can anticipate the operation of other gNBs 100s. For example, the control unit 120 of this embodiment can anticipate that the control unit 120 of another gNB 100 executes LTM.

[0058] (3) Operation of the wireless communication system (3.1) Challenges There was a request to perform carrier aggregation (CA) at the LTM transition destination. Therefore, it is being considered that secondary cells (SCells) other than primary cells can be set as the target cell of the LTM, in addition to primary cells (PCells). However, it has not been sufficiently considered which specific sequence of the complex sequence that realizes the LTM it is desirable to receive information about SCells. For example, the sequence differs depending on whether RACH is performed or omitted in the LTM. Therefore, the instruction to include information about SCells cannot be just any instruction; it needs to be selected.

[0059] (3.2) Operation Examples 1 to 3 of the embodiment will be described with reference to Figures 6 to 9. Operation Example 1 describes the LTM between DUs (Source DU, Target DU) controlled by the same gNB100. Operation Examples 2 and 3 describe the LTM between different gNB100s (gNB100A, gNB100B). In Operation Examples 2 and 3, gNB100A is assumed to be the Source gNB (CU) and gNB100B is assumed to be the Target gNB (CU).

[0060] In this disclosure, operation examples 1 to 3 of the embodiments mainly describe "configuration information related to SCell," but the "configuration information related to PCell" described above is also transmitted and received within the gNB100, between gNB100s, or between the gNB100 and the UE200, similar to the configuration information related to SCell. That is, "configuration information related to SCell" in operation examples 1 to 3 of the embodiments may be read as "configuration information related to PCell and configuration information related to SCell."

[0061] Figure 6 shows an example of a MAC CE common to operation examples 1 to 3. This MAC CE is an extension of the LTM Cell Switch Command MAC CE shown in TS 38.321, Figure 6.1.3.75-1. That is, the MAC CE shown in Figure 6 includes not only the Target Config ID, which is the configuration information for the PCell to transition to, but also the SCell Config ID, which is the configuration information for the SCell to transition to. This MAC CE may be understood to correspond to the Cell switch command in Figures 7 to 9.

[0062] (3.2.1) Operation Example 1 Figure 7 is a sequence diagram of the LTM between DUs (Source DU, Target DU) controlled by the same gNB100. In Figure 7, the gNB100 is assumed to consist of a Source DU and a Target DU, and a CU (gNB-CU in the figure) that controls these DUs.

[0063] First, the UE200 measures the cell quality of adjacent PCells and SCells and transmits the measurement results to the gNB100 (step S01). This transmission of measurement results may be called L3 measurement reporting. Next, the CU of the gNB100 determines the target cells (PCells and SCells) to be targeted for LTM (step S02) and requests the Target DU to configure the UE context, such as a wireless bearer (step S03). This request may include LTM information setup, which requests the configuration of LTM information.

[0064] The Target DU responds to the CU with a permission / denial of the request to configure the UE context (step S04). This response may include configuration information about the LTM (LTM config). The LTM config may include information such as SSB info containing information about SSBs, a complete candidate config indicator showing information about candidate cell configuration, and LTM CFRA resource config and LTM CFRA resource config for SUL which configure Contention Free Random Access (CFRA) resources in the LTM. Furthermore, the LTM config in this example may also include the SCell config info mentioned above. Note that, in this example, the request to configure the UE context is assumed to be permitted.

[0065] The CU sends and receives messages with the Source DU requesting the above-mentioned change to the UE context, and reply messages to those messages (steps S05, S06). These messages may include LTM information modify, which requests / permits changes to the LTM information. LTM information modify may include not only the SCell config info mentioned above, but also the LTM indicator, the CSI resource config which sets up the CSI-RS resources, and the list of the LTM CFRA resource config mentioned above. Here as well, the request to change the UE context is assumed to be permitted.

[0066] The CU sends and receives messages with the Target DU requesting the aforementioned change to the UE context, and a reply message to that message (steps S07, S08). The content of these messages is the same as the content of the messages sent and received in steps S05 and S06, so we will omit the explanation.

[0067] The CU sends an RRCReconfiguration message to the UE200 via the Source DU (steps S09, S10). The RRCReconfiguration message may include the SCell config described above. Note that the DL RRC message transfer message shown in S09 shall include the RRCReconfiguration message.

[0068] The UE200 sends an RRCReconfigurationComplete message to the CU via the Source DU (steps S11, S12). The UL RRC message transfer message shown in S11 includes the RRCReconfiguration message.

[0069] The steps S13 to S16 described below are a sequence related to early TA acquisition, assuming RACH-less LTM. In other words, steps S13 to S16 are an arbitrary sequence, and in the case of RACH-based LTM, the process may proceed to step S17 after step S12. It should also be understood that early TA acquisition is a sequence in which the Source DU acquires the timing advance (TA) value of the target cell to which the UE200 will transition in advance.

[0070] First, the Source DU sends a PDCCH order to the UE200 that triggers random access (step S13). The PDCCH order may include the ID of the target cell (SCell ID). Next, the UE200 sends a preamble to the Target DU (step S14).

[0071] The Target DU sends a DU-CU TA information transfer message to the CU (step S15). The DU-CU TA information transfer message includes information such as the SCell ID. For example, the DU-CU TA information transfer message may include not only the SCell ID, but also the TA value of the SCell, the preamble index, the identifier used in random access (RA-RNTI), the Source DU identifier (Source gNB DU ID), and a pointer to the Timing Advance Group (TAG) identifier (Tag ID pointer). The CU transfers the contents of the DU-CU TA information transfer message to the Source DU (step S16). This allows the Source DU to obtain the TA value of the SCell that will be the destination of the UE200 transition.

[0072] The UE200 measures the cell quality of the SCell set in step S10 and transmits the measurement results to the Source DU (step S17). This transmission of measurement results may be called L1 measurement reporting. The measurement results may include the ID of the SCell being measured (SCell ID or SCell beam ID), the resource indicator (SSBRI) of the SCell's SSB, and the cell quality of the SCell. The SCell's cell quality may be the SCell's SSB or the RSRP / RSRQ / SINR of the CSI-RS. Note that the SCell's cell quality may be interpreted as the SCell's beam quality.

[0073] The Source DU determines the LTM (Longest Time Measuring Time) based on the cell quality of the SCell included in the L1 measurement reporting described above (step S18) and sends a cell switch command to the UE200 (step S19).

[0074] The cell switch command may include, in addition to the SCell config ID mentioned above, the SCell's TA value used when performing LTM on the SCell in RACH-less mode, and the RACH resource used when performing LTM on the SCell in RACH-based mode. The RACH resource may include, for example, the preamble index, the SSB index, the PRACH mask index, the number of preamble iterations, and the S / U indicator. The S / U indicator is an indicator that shows the UL carrier when sending the preamble (PRACH) with the CFRA's RACH resource.

[0075] The cell switch command may include the SCell activation / deactivation field or the SCell activated / deactivated field. Note that the SCell activation / deactivation field or SCell activated / deactivated field may be interpreted as the SCell beam activation / deactivation field or SCell beam activated / deactivated field. Furthermore, the cell switch command may include the SCell's TCI state ID or UL TCI state ID. Note that TCI may mean Transmission Configuration Indication.

[0076] It may be understood that the transmission of the cell switch command executes a transition (LTM) of UE200. In this case, the entity executing the LTM of UE200 may be understood as gNB100, UE200, or both gNB100 and UE200. Furthermore, through the LTM in this example, UE200 can transition not only to PCells but also to SCells among the cells formed by the Target DU.

[0077] After the Source DU sends a cell switch command to the UE200, it sends a cell switch notification to the Target DU via the CU (steps S20, S21). The cell switch notification includes information such as the SCell ID to which the UE200 transitions. For example, the cell switch notification may include not only the SCell ID, but also the TA value, TCI state ID, and Tag ID pointer of that SCell.

[0078] Finally, UE200 sends an RRCReconfigurationComplete message to Target DU indicating the completion of the LTM (step S22).

[0079] In this example, the Intra-CU LTM allows the UE200 to transition not only to PCells but also to SCells among the cells formed by the Target DU. In other words, the UE200 in this example can perform CA on both PCells and SCells formed by the Target DU using the Intra-CU LTM.

[0080] (3.2.2) Operation Example 2 Figure 8 is a sequence diagram of LTM between different gNB100s (gNB100A, gNB100B).

[0081] First, the UE200 measures the cell quality of adjacent PCells and SCells and transmits the measurement results to the gNB100A (step S31). This transmission of measurement results may be called L3 measurement reporting. Next, the gNB100A sends an LTM request message to the gNB100B requesting LTM (step S32). This LTM request message may include an LTM information setup requesting the configuration of LTM information.

[0082] If gNB100B approves the LTM request, it sends an LTM request Ack message to gNB100A (step S33). The LTM request Ack message may include configuration information about the LTM (LTM config). The LTM config may include existing information such as SSB info containing information about SSBs, a complete candidate config indicator showing information about the configuration of candidate cells, and an LTM CFRA resource config and an LTM CFRA resource config for SUL that configure Contention Free Random Access (CFRA) resources in the LTM. This information is described in specifications such as 3GPP TS 38.473 and TS 38.331. Furthermore, the LTM config in this example may include the SCell config info mentioned above.

[0083] gNB100A sends an RRCReconfiguration message to UE200 (step S34). The RRCReconfiguration message may include the SCell config described above. UE200 sends an RRCReconfigurationComplete message to gNB100B (step S35).

[0084] The steps S36 to S38 described below are a sequence related to early TA acquisition based on RACH-less LTM. That is, steps S36 to S38 are an arbitrary sequence, and in the case of RACH-based LTM, the process may proceed to step S39 after step S35. It should also be understood that early TA acquisition is a sequence in which gNB100A acquires the timing advance (TA) value of the target cell to which UE200 will transition in advance.

[0085] First, gNB100A sends a PDCCH order to UE200 that triggers random access (step S36). The PDCCH order may include the ID of the target cell (SCell ID). Next, UE200 sends a preamble to gNB100B (step S37).

[0086] gNB100B sends a TA information transfer message to gNB100A (step S38). The TA information transfer message includes information such as the SCell ID. For example, the TA information transfer message may include not only the SCell ID, but also the TA value of the SCell, the preamble index, the identifier used in random access (RA-RNTI), the Source gNB identifier (Source CU ID), the identifier of the DU controlled by the Source gNB (Source gNB DU ID), and a pointer to the Timing Advance Group (TAG) identifier (Tag ID pointer). This allows gNB100A to obtain the TA value of the SCell to which UE200 will transition.

[0087] The UE200 measures the cell quality of the SCell set in step S34 and transmits the measurement result to the gNB100A (step S39). This transmission of the measurement result may be called L1 measurement reporting. The measurement result may include the ID of the SCell being measured (SCell ID or SCell beam ID), the resource indicator (SSBRI) of the SCell's SS / PBCH block (SSB), and the cell quality of the SCell. The SCell's cell quality may be the SCell's SSB or the RSRP / RSRQ / SINR of the CSI-RS. Note that the SCell's cell quality may be interpreted as the SCell's beam quality.

[0088] Based on the cell quality of the SCell included in the L1 measurement reporting described above, the gNB100A determines the LTM (step S40) and sends a cell switch command to the UE200 (step S41).

[0089] The cell switch command may include, in addition to the SCell config ID mentioned above, the SCell's TA value used when performing LTM on the SCell in RACH-less mode, and the RACH resource used when performing LTM on the SCell in RACH-based mode. The RACH resource may include, for example, the index of the random access preamble, the index of the SSB, the mask index of the PRACH, the number of preamble iterations, and the S / U indicator. The S / U indicator is an indicator that shows the UL carrier when sending the preamble (PRACH) with the CFRA's RACH resource.

[0090] The cell switch command may include the SCell activation / deactivation field or the SCell activated / deactivated field. Note that the SCell activation / deactivation field or SCell activated / deactivated field may be interpreted as the SCell beam activation / deactivation field or SCell beam activated / deactivated field. Furthermore, the cell switch command may include the SCell's TCI state ID or UL TCI state ID. Note that TCI may mean Transmission Configuration Indication.

[0091] It may be understood that the transmission of the cell switch command executes a transition (LTM) of UE200. In this case, the entity executing the LTM of UE200 may be understood as gNB100, UE200, or both gNB100 and UE200. Furthermore, through the LTM in this example, UE200 can transition not only to PCells but also to SCells among the cells formed by the Target DU.

[0092] After sending a cell switch command to UE200, gNB100A sends a cell switch notification to gNB100B (step S42). The cell switch notification includes information such as the SCell ID to which UE200 is transitioning. For example, the cell switch notification may include not only the SCell ID, but also the TA value, TCI state ID, and Tag ID pointer of the SCell. gNB100B sends an Access success message to gNB100A (step S43).

[0093] Finally, UE200 sends an RRCReconfigurationComplete message to gNB100B indicating the completion of the LTM (step S44).

[0094] In this example, Inter-CU LTM allows UE200 to transition not only to PCells but also to SCells among the cells formed by gNB100B. In other words, in this example, UE200 can perform CA on both PCells and SCells formed by gNB100B using Inter-CU LTM.

[0095] (3.2.3) Operation Example 3 Figure 9 is a sequence diagram of LTM between gNB100s where an Xn interface is not provided. Since such an LTM transmits and receives the information necessary for LTM between gNB100s via CN30, it may also be called NG LTM, after the NG interface that connects CN30 and gNB100. In other words, Figure 9 is a sequence diagram of NG LTM.

[0096] First, UE200 measures the cell quality of adjacent PCells and SCells and sends the measurement results to gNB100A (step S51). This transmission of measurement results may be called L3 measurement reporting. Next, gNB100A sends an HO required message to AMF300 requesting LTM (step S52). The HO required message may also include LTM information setup, which requests the configuration of LTM information. Note that LTM information setup may be included in the Source NG-RAN to Target NG-RAN Node Transparent Container within the HO required message.

[0097] AMF300 forwards the information contained in the HO required message to gNB100B, including it in the HO request message (step S53). Note that the forwarded information may also be included in the Source NG-RAN to Target NG-RAN Node Transparent Container within the HO request message.

[0098] If gNB100B approves the LTM request, it sends an HO request Ack message to AMF300 (step S54). The HO required Ack message may include configuration information about the LTM (LTM config). The LTM config may include existing information such as SSB info containing information about SSBs, a complete candidate config indicator showing information about the configuration of candidate cells, and LTM CFRA resource config and LTM CFRA resource config for SUL which configure Contention Free Random Access (CFRA) resources in the LTM. This information is described in specifications such as 3GPP TS 38.473 and TS 38.331. Furthermore, the LTM config in this example may also include the SCell config info mentioned above. This information may also be included in the Target NG-RAN Node to Source NG-RAN Node Transparent Container within the HO required Ack message.

[0099] The AMF300 forwards the information contained in the HO required Ack message to the gNB100A, including it in the HO command (step S55). The forwarded information may also be included in the Target NG-RAN Node to Source NG-RAN Node Transparent Container within the HO command.

[0100] The gNB100A sends an RRCReconfiguration message to the UE200 (step S56). The RRCReconfiguration message may include the SCell config described above.

[0101] The steps S57 to S60 described below are sequences related to early TA acquisition based on RACH-less LTM. In other words, steps S57 to S60 are arbitrary sequences, and in the case of RACH-based LTM, the process may proceed from step S56 to step S61. It should also be understood that early TA acquisition is a sequence in which gNB100A acquires the timing advance (TA) value of the target cell to which UE200 will transition in advance.

[0102] First, gNB100A sends a PDCCH order to UE200 that triggers random access (step S57). The PDCCH order may include the ID of the target cell (SCell ID). Next, UE200 sends a preamble to gNB100B (step S58).

[0103] gNB100B sends a TA information transfer message to AMF300 (step S59). The TA information transfer message includes information such as the SCell ID. For example, the TA information transfer message may include not only the SCell ID, but also the TA value of the SCell, the preamble index, the identifier used in random access (RA-RNTI), the Source gNB identifier (Source CU ID), the identifier of the DU controlled by the Source gNB (Source gNB DU ID), and a pointer to the Timing Advance Group (TAG) identifier (Tag ID pointer). AMF300 transfers the contents of the TA information transfer message to gNB100A (step S60). This allows gNB100A to obtain the TA value of the SCell that will be the destination of the UE200 transition.

[0104] The UE200 measures the cell quality of the SCell set in step S56 and transmits the measurement result to the gNB100A (step S61). This transmission of the measurement result may be called L1 measurement reporting. The measurement result may include the ID of the SCell being measured (SCell ID or SCell beam ID), the resource indicator (SSBRI) of the SCell's SS / PBCH block (SSB), and the cell quality of the SCell. The SCell's cell quality may be the SCell's SSB or the RSRP / RSRQ / SINR of the CSI-RS. Note that the SCell's cell quality may be interpreted as the SCell's beam quality.

[0105] Based on the cell quality of the SCell included in the L1 measurement reporting described above, the gNB100A determines the transition of the UE200 and sends a cell switch command to the UE200 (step S62).

[0106] The cell switch command may include, in addition to the SCell config ID mentioned above, the SCell's TA value used when performing LTM on the SCell in RACH-less mode, and the RACH resource used when performing LTM on the SCell in RACH-based mode. The RACH resource may include, for example, the index of the random access preamble, the index of the SSB, the mask index of the PRACH, the number of preamble iterations, and the S / U indicator. The S / U indicator is an indicator that shows the UL carrier when sending the preamble (PRACH) with the CFRA's RACH resource.

[0107] The cell switch command may include the SCell activation / deactivation field or the SCell activated / deactivated field. Note that the SCell activation / deactivation field or SCell activated / deactivated field may be interpreted as the SCell beam activation / deactivation field or SCell beam activated / deactivated field. Furthermore, the cell switch command may include the SCell's TCI state ID or UL TCI state ID. Note that TCI may mean Transmission Configuration Indication.

[0108] It may be understood that the transmission of the cell switch command executes a transition (LTM) of UE200. In this case, the entity executing the LTM of UE200 may be understood as gNB100, UE200, or both gNB100 and UE200. Furthermore, through the LTM in this example, UE200 can transition not only to PCells but also to SCells among the cells formed by the Target DU.

[0109] After sending a cell switch command to UE200, gNB100A sends a cell switch notification to gNB100B (step S63). The cell switch notification includes information such as the SCell ID to which UE200 will transition. For example, the cell switch notification may include not only the SCell ID, but also the TA value, TCI state ID, and Tag ID pointer of the SCell. gNB100B forwards the cell switch notification to gNB100A (step S64).

[0110] Finally, UE200 sends an RRCReconfigurationComplete message to gNB100B indicating the completion of LTM (step S65).

[0111] In this example, NG LTM allows UE200 to transition not only to PCells but also to SCells among the cells formed by gNB100B. In other words, in this example, UE200 can perform CA on both PCells and SCells formed by gNB100B using NG LTM.

[0112] (3.2.4) Settings applicable to Operation Examples 1-3 The settings applicable to Operation Examples 1-3 will be described. First, the settings related to the measurement report of cell quality by UE200 will be described. Next, the settings when LTM is the conditional LTM described above will be described.

[0113] (3.2.4.1) Settings for Cell Quality Measurement Reporting The UE200 may transmit the L1 beam quality of the target cell (or candidate cell) to the gNB100 via PUCCH. Alternatively, the UE200 may transmit the L1 beam quality of the target cell (or candidate cell) to the gNB100 via MAC CE. Note that the L1 beam quality may be understood as the RSRP / RSRQ / SINR of the SSB or CSI-RS as described above.

[0114] The UE200 may transmit the quality of the L1 beam of the target cell (or candidate cell) on a periodic basis, or based on the occurrence of an event. The event may be either Event LTM2 or Event LTM4, as shown below. Note that the events are as specified in 3GPP TS 38.300. ・Event LTM2: The serving cell's beam falls below an absolute value. ・Event LTM3: The candidate cell's beam has a greater offset than the serving cell's beam. ・Event LTM4: The candidate cell's beam exceeds an absolute value. ・Event LTM5: The serving cell's beam falls below a certain absolute value, and the candidate cell's beam exceeds another absolute value.

[0115] (3.2.4.2) Settings for Conditional LTM In the case of Conditional LTM, the UE200 may simultaneously receive two LTM execution conditions from the gNB100. The LTM execution conditions may also be called execution conditions and may be understood as conditions under which the UE200 autonomously performs cell switching depending on the cell quality of the target cell. The UE200 may also monitor both LTM execution conditions.

[0116] UE200 may cell switch to both PCell and SCell, which are target cells, if both of the two LTM execution conditions are satisfied. The two LTM execution conditions may be condEvent LTM3 and condEvent LTM4, or condEvent LTM5 and condEvent LTM4, from among those shown below. Note that the LTM execution conditions may be understood to be the same as the events that trigger the measurement report described above. ・condEvent LTM2: The beam of the serving cell falls below an absolute value. ・condEvent LTM3: The beam of the candidate cell has a larger offset than the beam of the serving cell. ・condEvent LTM4: The beam of the candidate cell exceeds an absolute value. ・condEvent LTM5: The beam of the serving cell falls below a certain absolute value, and the beam of the candidate cell exceeds another absolute value.

[0117] (4) Operation and Effects According to the embodiment described above, by including setting information related to SCell in the cell switch command (MAC CE), regardless of whether the LTM is RACH-less or RACH-based, it is possible to transition to SCell as well as PCell in the LTM and realize CA at the destination.

[0118] According to the embodiment described above, the cell quality of the SCell can be transmitted to the gNB100, so that a transition to the SCell can be made based on the cell quality, similar to the transition to the PCell.

[0119] According to the embodiment described above, when the LTM is RACH-less, the PDCCH order can include configuration information related to SCell. This allows the UE200 to be configured with SCell configuration information by utilizing the sequence of the RACH-less LTM.

[0120] According to the embodiment described above, even if the LTM is a Conditional LTM, it is possible to transition not only to PCell but also to SCell, and to realize CA at the destination.

[0121] (5) Other Embodiments Although the contents of the present invention have been described above in accordance with the embodiments, it will be obvious to those skilled in the art that the present invention is not limited to these descriptions and that various modifications and improvements are possible.

[0122] In the embodiments described above, the term "candidate cell" was used to mean "a cell that is a candidate for the target cell (the cell to which UE200 transitions)," but it may be replaced with "target cell" as long as it does not create a contradiction. Furthermore, "target cell" may also be replaced with "candidate cell."

[0123] The embodiments described above may be applied to Dual Connectivity (DC) that connects multiple gNB100s simultaneously. That is, the embodiments described above may be applied to primary secondary cells (PSCell) and SCells formed by secondary nodes (SNs) in a DC. That is, the embodiments described above may be applied to LTMs that change SNs in a DC. Thus, the first cell may be a primary cell (PCell) in a master cell group (MCG) formed by a master node (MN), a primary secondary cell (PSCell) in a secondary cell group (SCG) formed by secondary nodes (SNs), or a Special cell (SPCell). The second cell may be a secondary cell (SCell) in an MCG or SCG. That is, the embodiments described above are applicable to LTMs of CAs in MCGs and CAs in SCGs in a DC.

[0124] The examples of operation described above may be combined and applied in combination, as long as no inconsistencies arise.

[0125] The block diagrams used in the description of the above embodiments show functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, 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 software with the one or more of the above devices.

[0126] 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 all cases, as mentioned above, the method of implementation is not particularly limited.

[0127] For example, the base station 100 and terminal 200 in one embodiment of the present disclosure may function as computers that process the wireless communication method of the present disclosure. Figure 10 is a diagram showing an example of the hardware configuration of the base station 100 and terminal 200 according to one embodiment of the present disclosure. The above-mentioned base station 100 and terminal 200 may be physically configured as computer devices including a processor 1001, memory 1002, storage 1003, communication device 1004, input device 1005, output device 1006, bus 1007, etc.

[0128] In the following explanation, the term "device" can be replaced with "circuit," "device," "unit," etc. The hardware configuration of the base station 100 and terminal 200 may include one or more of the devices shown in the figure, or it may be configured to omit some of the devices.

[0129] Each function in the base station 100 and terminal 200 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 the reading and writing of data in the memory 1002 and storage 1003.

[0130] 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.

[0131] 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. Furthermore, although it has been explained that the above processes are executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may also be transmitted from a network via a telecommunications line.

[0132] 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 executable programs (program code), software modules, etc., for carrying out a wireless communication method according to one embodiment of the present disclosure.

[0133] The 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., Compact Disc, Digital Multipurpose Disc, Blu-ray® Disc), a smart card, flash memory (e.g., a card, stick, key drive), a floppy® disk, a magnetic strip, etc. The storage 1003 may also be called an auxiliary storage device. The above-mentioned storage medium may be, for example, a database, server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0134] 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 referred to as a network device, network controller, network card, communication module, etc. The communication device 1004 may be configured to include, for example, a high-frequency switch, duplexer, filter, frequency synthesizer, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD).

[0135] 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).

[0136] Furthermore, each device, such as the processor 1001 and 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.

[0137] Furthermore, the base station 100 and terminal 200 may be configured to 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 realized by such hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0138] Information notification is not limited to the embodiments described herein and may be carried out by other means. For example, information notification may be carried out by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), upper layer signaling (e.g., Radio Resource Control (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.

[0139] Each aspect / embodiment described herein may apply to systems utilizing Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (where x is, for example, an integer or decimal), Future Radio Access (FRA), New Radio (NR), New radio access (NX), Future generation radio access (FX), 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 at least one of the next-generation systems that are extended, modified, created, or defined 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).

[0140] The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described in this disclosure may be reordered, provided they do not contradict each other. For example, the methods described in this disclosure present various step elements using exemplary order and are not limited to the specific order presented.

[0141] 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).

[0142] 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.

[0143] 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 transmitted to other devices.

[0144] The determination may be made by a value represented by one bit (0 or 1), by a boolean value (true or false), or by a numerical comparison (for example, by comparing with a predetermined value).

[0145] Each aspect / embodiment described in this disclosure 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).

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] The terms “system” and “network” as used in this disclosure are interchangeable.

[0151] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or corresponding other information. For example, wireless resources may be indicated by an index.

[0152] 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. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, and therefore, the various names assigned to these various channels and information elements are not restrictive in any way.

[0153] 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.

[0154] 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 may be provided with communication services by a base station subsystem (e.g., a Remote Radio Head, RRH). The terms "cell" or "sector" refer to part or all of the coverage area of ​​at least one of the base station and / or base station subsystems providing communication services in that coverage.

[0155] In this disclosure, the transmission of information by a base station to a terminal may be interpreted as the base station instructing the terminal to perform control or operation based on the information.

[0156] In this disclosure, terms such as “terminal,” “user terminal,” “Mobile Station (MS),” and “User Equipment (UE)” may be used interchangeably.

[0157] 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 several other appropriate terms.

[0158] 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 also be a device mounted on a mobile body, the mobile body itself, etc. The mobile body refers to a movable object, and its speed of movement is arbitrary. This also includes the case when the mobile body is stationary. The mobile body includes, but is not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcarts, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and items mounted on them. The mobile body may also be a mobile body that moves autonomously based on operation commands. It 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). Furthermore, at least one of the base station and the mobile station may include devices that do not necessarily move during communication operations. 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.

[0159] Furthermore, the term "base station" in this disclosure may be interpreted as "terminal." For example, the various aspects / embodiments of this disclosure may be applied to a configuration in which communication between a base station and a terminal is replaced with communication between multiple terminals (which may be called, for example, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.). In this case, the terminal 200 may have the functions that the base station 100 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.

[0160] Similarly, the term "terminal" in this disclosure may be replaced with "base station." In this case, the base station 100 may be configured to have the same functions as the terminal 200 described above.

[0161] Figure 11 shows an example of the configuration of vehicle 2001. As shown in Figure 11, vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013.

[0162] The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor.

[0163] The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel, which is operated by the user.

[0164] The electronic control unit 2010 consists of a microprocessor 2031, memory (ROM, RAM) 2032, and communication ports (IO ports) 2033. Signals from various sensors 2021 to 2027 installed in the vehicle are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an Electronic Control Unit (ECU).

[0165] Signals from various sensors 2021 to 2029 include current signals from the current sensor 2021 that senses motor current, front and rear wheel rotation speed signals obtained by the rotation speed sensor 2022, front and rear wheel air pressure signals obtained by the air pressure sensor 2023, vehicle speed signals obtained by the vehicle speed sensor 2024, acceleration signals obtained by the acceleration sensor 2025, accelerator pedal depression signals obtained by the accelerator pedal sensor 2029, brake pedal depression signals obtained by the brake pedal sensor 2026, shift lever operation signals obtained by the shift lever sensor 2027, and detection signals obtained by the object detection sensor 2028 for detecting obstacles, vehicles, pedestrians, etc.

[0166] The Information Services Unit 2012 consists of various devices for providing (outputting) various types of information such as driving information, traffic information, and entertainment information, including car navigation systems, audio systems, speakers, televisions, and radios, and one or more ECUs that control these devices. The Information Services Unit 2012 uses information acquired from external devices via communication modules 2013, etc., to provide various multimedia information and multimedia services to the occupants of the vehicle 2001.

[0167] The Information Services Unit 2012 may include input devices that accept input from external sources (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) and output devices that output to external sources (e.g., displays, speakers, LED lamps, touch panels, etc.).

[0168] The driver assistance system unit 2030 consists of various devices that provide functions to prevent accidents or reduce the driver's workload, such as millimeter-wave radar, Light Detection and Ranging (LiDAR), cameras, positioning locators (e.g., GNSS), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps), gyro systems (e.g., Inertial Measurement Unit (IMU), Inertial Navigation System (INS)), Artificial Intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. The driver assistance system unit 2030 also sends and receives various information via the communication module 2013 to realize driver assistance functions or autonomous driving functions.

[0169] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via its communication port. For example, the communication module 2013 sends and receives data via the communication port 2033 between the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axle 2009, the microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 2029 provided in the vehicle 2001.

[0170] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with external devices. For example, it can send and receive various types of information to and from external devices via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station or a mobile station.

[0171] The communication module 2013 may transmit at least one of the following to an external device via wireless communication: signals from the various sensors 2021 to 2029 input to the electronic control unit 2010, information obtained based on said signals, and information based on input from an external source (user) obtained via the information service unit 2012. The electronic control unit 2010, the various sensors 2021 to 2029, the information service unit 2012, etc., may also be called input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above input.

[0172] The communication module 2013 receives various information (traffic information, signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on the information service unit 2012 installed in the vehicle. The information service unit 2012 may also be called an output unit, which outputs information (for example, it outputs information to devices such as displays and speakers based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013).

[0173] Furthermore, the communication module 2013 stores various information received from external devices in memory 2032, which is available to the microprocessor 2031. Based on the information stored in memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axles 2009, sensors 2021 to 2029, etc., which are provided in the vehicle 2001.

[0174] 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, or inquiring (e.g., searching in a table, database, or other data structure), or ascertaining. “Determining” may also include receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, or accessing (e.g., accessing data in memory). Furthermore, “determining” may include resolving, selecting, choosing, establishing, or comparing. In other words, "judgment" and "decision" can include considering that some action has been "judged" or "decided." Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering."

[0175] The terms “connected,” “coupled,” and any variations 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.

[0176] The reference signal may also be abbreviated as RS, and may be called Pilot depending on the applicable standard.

[0177] 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."

[0178] Any reference to elements using the designations “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, or that the first element must precede the second element in any way.

[0179] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0180] 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.

[0181] A wireless frame may consist of one or more frames in the time domain. Each of these 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.

[0182] 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.

[0183] A slot may consist of one or more symbols in the time domain (such as Orthogonal Frequency Division Multiplexing (OFDM) symbols or Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols). A slot may also be a time unit based on neurology.

[0184] A slot may include multiple mini-slots. Each mini-slot may consist of one or more symbols in the time domain. Mini-slots may also be called sub-slots. Mini-slots may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a mini-slot may be called a PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may be called a PDSCH (or PUSCH) mapping type B.

[0185] 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.

[0186] For example, one subframe may be called a transmission 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 to 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.

[0187] 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 terminal to allocate radio resources (such as the frequency bandwidth and transmission power available to each terminal) in TTI units. However, the definition of TTI is not limited to this.

[0188] 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. Note that when a TTI is given, the actual time interval (e.g., number of symbols) in which the transport block, code block, code word, etc. are mapped may be shorter than the given TTI.

[0189] 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 the minimum time unit of scheduling may be controlled.

[0190] A TTI with a time length of 1 ms may also be called a normal TTI (TTI in LTE Rel. 8-12), a long TTI, a normal subframe, a long subframe, or a slot. A TTI shorter than a normal TTI may also be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a mini slot, a subslot, or a slot.

[0191] 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.

[0192] 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.

[0193] Furthermore, the time domain of 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.

[0194] One or more RBs may also be called Physical RBs (PRBs), Sub-Carrier Groups (SCGs), Resource Element Groups (REGs), PRB pairs, RB pairs, etc.

[0195] Furthermore, a resource block may consist of one or more resource elements (REs). For example, one RE may be a radio resource area of ​​one subcarrier and one symbol. A bandwidth part (BWP) (also called a partial bandwidth, etc.) may represent a subset of consecutive common resource blocks (RBs) for a given neurology in a given carrier. Here, the common RBs may be identified by an index of the RBs relative to the common reference point of the carrier. PRBs may be defined in a BWP and numbered within that BWP.

[0196] A BWP may include BWPs for UL (UL BWP) and BWPs for DL ​​(DL BWP). One or more BWPs may be configured within a single carrier for a UE.

[0197] 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".

[0198] 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 a TTI can be varied in various ways.

[0199] The term "maximum transmit power" as used in this disclosure may mean the maximum transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0200] 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.

[0201] 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."

[0202] 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 can be implemented in modified and altered forms without departing from the intent and scope of the present disclosure as defined by the claims. Therefore, the descriptions in the present disclosure are illustrative and not intended to be restrictive in any way.

[0203] (Note) The disclosure described above may also be expressed as follows:

[0204] The first feature is that the device comprises a receiving unit that receives instructions from a base station to perform a transition of lower-layer control to a distributed device of the base station or another base station, and a control unit that, in response to the instructions, communicates with a first carrier that provides a first cell with which a connection is first established in the transition, and a second carrier that provides a second cell other than the first cell, wherein the receiving unit is a terminal that receives the instructions which include first setting information relating to the first cell and second setting information relating to the second cell.

[0205] The second feature is that, in the first feature, the receiving unit may be a terminal that receives the instruction via a control element of the media access control layer.

[0206] A third feature is that, in the first or second feature, the base station may be equipped with a transmitting unit that transmits the cell quality of the second cell.

[0207] A fourth feature is that, in any of the first to third features, the timing advance value of the second cell is transmitted from the distributed device or the other base station to the base station, and the control unit may be a terminal that omits the initial access procedure in the transition.

[0208] A fifth feature is that, in any of the first to fourth features, the control unit may be a terminal that performs the communication when both the first condition relating to the cell quality of the first cell and the cell quality of the second cell, and the second condition relating only to the cell quality of the second cell, are met.

[0209] The sixth feature is that, in the fifth feature, the receiving unit may be a terminal that receives third setting information, including the first condition and the second condition, from the base station.

[0210] 10 Wireless communication system 20 NG-RAN 30 CN 100 Base station 110 Wireless signal transmission / reception unit 120 Control unit 200 Terminal 210 Wireless signal transmission / reception unit 220 Amplifier unit 230 Modulation / demodulation unit 240 Control signal / reference signal processing unit 250 Encoding / decoding unit 260 Data transmission / reception unit 270 Control unit 300 AMF 400 NWDAF 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Left and right front wheels 2008 Left and right rear wheels 2009 Axle 2010 Electronic Control Unit 2012 Information Services Unit 2013 Communication Module 2021 Current Sensor 2022 Rotation Speed ​​Sensor 2023 Air Pressure Sensor 2024 Vehicle Speed ​​Sensor 2025 Acceleration Sensor 2026 Brake Pedal Sensor 2027 Shift Lever Sensor 2028 Object Detection Sensor 2029 Accelerator Pedal Sensor 2030 Driving Assistance System Unit 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication Port (IO Port)

Claims

1. A terminal comprising: a receiving unit that receives instructions from a base station to perform a transition of lower-layer control to a distributed device of the base station or another base station; and a control unit that, in response to the instructions, communicates with a first carrier that provides a first cell with which a connection is first established in the transition, and a second carrier that provides a second cell other than the first cell, wherein the receiving unit receives the instructions which include first setting information relating to the first cell and second setting information relating to the second cell.

2. The terminal according to claim 1, wherein the receiving unit receives the instruction via a control element of the media access control layer.

3. The terminal according to claim 1, wherein the base station is equipped with a transmitting unit for transmitting the cell quality of the second cell.

4. The terminal according to claim 1, wherein the timing advance value of the second cell is transmitted to the base station from the distributed device or the other base station, and the control unit omits the initial access procedure in the transition.

5. The terminal according to claim 1, wherein the control unit performs the communication when both the first condition relating to the cell quality of the first cell and the cell quality of the second cell and the second condition relating only to the cell quality of the second cell are met.

6. The terminal according to claim 5, wherein the receiving unit receives from the base station a third setting information including the first condition and the second condition.

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