Terminal

Abstract

A terminal according to the present invention comprises: a reception unit that receives information about a second cell that is formed by a second carrier that has a higher frequency band than a first carrier from a first cell that is formed by the first carrier; and a control unit that executes a transition from the first cell to the second cell on the basis of the information about the second cell.

Description

Terminal

[0001] The present disclosure relates to a terminal that transitions to a target cell.

[0002] The 3rd Generation Partnership Project (3GPP (registered trademark)) standardizes the 5th generation mobile communication system (also referred to as 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] A terminal connected to a cell formed by a base station can transition to another cell, for example, according to the communication quality of the cell. Such cell transition is also called mobility (Non-Patent Document 1).

[0004] 3GPP TS 38.300 V18.4.0, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; NR and NG-RAN Overall Description; Stage 2 (Release 18), 3GPP, December 2024

[0005] By the way, in the 6G mobile communication system, not only data carriers mainly used for user data communication, but also the introduction of p-carrying carriers for the purpose of, for example, a terminal waiting (camp on) in preparation for user data communication is being considered. Also, instead of introducing p-carrying carriers, the function of p-carrying carriers is being considered to be borne by anchor carriers mainly used for control data communication. Thus, when a plurality of carriers with different uses are introduced, the problem of what kind of mobility control is suitable has not been fully considered.

[0006] Therefore, an object of the present disclosure is to provide a terminal that can realize suitable mobility when a plurality of carriers with different uses are introduced.

[0007] One aspect of the disclosure is a terminal comprising: a receiving unit (wireless signal transmitting / receiving unit 210) that receives information from a first cell formed by a first carrier about a second cell formed by a second carrier having a higher frequency band than the first carrier; and a control unit (control unit 270) that performs a transition from the first cell to the second cell based on the information about the second cell.

[0008] Figure 1 is a schematic diagram of the overall configuration of a 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 a perch carrier. Figure 7 is a diagram showing an example of information transmitted in a perch carrier and a data carrier. Figure 8 is a diagram showing the sequence of HO. Figure 9 is a diagram showing the sequence of Xn HO. Figure 10 is a diagram showing the sequence of NG HO. Figure 11 is a diagram showing the sequence of Intra-CU LTM. Figure 12 is a diagram showing the sequence of Xn LTM. Figure 13 is a diagram showing the sequence of NG LTM. Figure 14 is a diagram showing an example of the hardware configuration of a base station and a terminal. Figure 15 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 100 (hereinafter also referred to as BS100) that constitutes the Next Generation-Radio Access Network (NG-RAN) 20, and a terminal 200 (hereinafter also referred to as user equipment (UE) 200) that communicates wirelessly with BS100. BS100 may also be called a RAN node.

[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. AMF300 performs, for example, the registration of UE200. NWDAF400 performs, for example, the optimization of CN30. Note that the specific configuration of the wireless communication system 10, such as the number of BS100 and UE200, 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] BS100 may consist of distributed units (DUs) that form cells to which 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, BS100 may consist of DUs, CU-CPs, and CU-UPs.

[0015] Furthermore, the wireless communication system 10 may support multiple frequency ranges (FRs). That is, as shown in Figure 2, 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

[0016] 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.

[0017] 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 applied.

[0018] Furthermore, 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.

[0019] 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.

[0020] (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.

[0021] The wireless signal transceiver 210 transmits and receives wireless signals to and from BS100. The wireless signal transceiver 210 may consist of a transmitting unit that transmits wireless signals to BS100 and a receiving unit that receives wireless signals from BS100. The wireless signals may include various types of information, or may be interpreted as various types of information. Transmission may be interpreted as reporting, notifying, etc. Reception may be interpreted as setting, instructing, notifying, etc. Setting may be implemented by setting information (information element (IE)) of the wireless 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).

[0022] The wireless signal transmitting and receiving unit 210 of this embodiment can receive information from a first cell formed by a first carrier about a second cell formed by a second carrier having a higher frequency band than the first carrier. The first carrier may be understood to correspond to a perch carrier (or anchor carrier) as described later. The second carrier may be understood to correspond to a data carrier as described later. The data carrier may also be called a non-anchor carrier.

[0023] The wireless signal transceiver 210 of this embodiment may receive a cell transition command that includes information about the second cell. The cell transition command may be understood to correspond to RRCReconfiguration or Cell switch command in the operation example (see Figures 8 to 13). The information about the second cell may be understood to mean information that the UE200 uses to access (perform initial access to) the second cell.

[0024] The wireless signal transceiver 210 of the embodiment may receive system information relating to the second cell as information relating to the second cell. The system information may be, for example, a master information block (MIB) or a system information block (SIB). The MIB may be transmitted via a physical broadcast channel (PBCH), and the SIB may be transmitted via a physical downlink sharing channel (PDSCH).

[0025] The wireless signal transceiver 210 of the embodiment may receive a physical broadcast channel demodulation reference signal (PBCH DMRS) relating to the second cell as information about the second cell. The physical broadcast channel demodulation reference signal (PBCH DMRS) is a reference signal (RS) for demodulating the PBCH.

[0026] 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.

[0027] The modulation / demodulation unit 230 performs data modulation / demodulation, transmission power setting, and resource block allocation for each predetermined communication destination (BS100 or other BS100). 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).

[0028] The control signal / reference signal processing unit 240 performs processing related to control signals transmitted to and from the BS100, such as radio resource control (RRC) signaling.

[0029] The control signal / reference signal processing unit 240 performs processing related to reference signals transmitted to and from the BS100, 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).

[0030] Channels include control channels and data channels. Control channels include physical uplink control channels (PUCCH), physical downlink control channels (PDCCH), physical random access channels (PRACH), and physical broadcast channels (PBCH). Data channels include physical uplink sharing channels (PUSCH) and physical downlink sharing channels (PDSCH).

[0031] The encoding / decoding unit 250 performs data splitting / concatenation and coding / decoding for each predetermined communication destination (BS100 or other BS100).

[0032] Specifically, the encoding / decoding unit 250 decodes the data output from the modulation / demodulation unit 230 and concatenates the decoded data. The encoding / decoding unit 250 also divides the data output from the data transmission / reception unit 260 into predetermined sizes and performs coding on the divided data.

[0033] The data transmission / reception unit 260 performs assembly / decomposition of data units (Protocol Data Units (PDUs) / Service Data Units (SDUs)) that constitute the data between each layer. The multiple layers include the Media Access Control (MAC) layer, the Radio Link Control (RLC) layer, and the Packet Data Convergence Protocol (PDCP) layer. The data transmission / reception unit 260 also performs error correction and retransmission control of the data based on the Hybrid Automatic Repeat Request (HARQ).

[0034] The control unit 270 controls the UE200. For example, the control unit 270 controls the transmission and reception of wireless signals by the wireless signal transmission / reception unit 210, amplification by the amplifier unit 220, data modulation / demodulation by the modulation / demodulation unit 230, signal processing by the control signal / reference signal processing unit 240, coding / decoding by the encoding / decoding unit 250, and assembly / disassembly of data units by the data transmission / reception unit 260.

[0035] The control unit 270 of the embodiment can perform a transition from the first cell to the second cell based on the information about the second cell described above. In this case, the first cell may be called a source cell, and the second cell may be called a target cell. In this disclosure, "cell" may be read as "beam".

[0036] The control unit 270 of the embodiment may perform a transition from the first cell to the second cell by controlling the radio resource control (RRC) layer. Such a transition between cells may be called a handover (HO) or L3 mobility.

[0037] The control unit 270 of the embodiment may perform the transition from the first cell to the second cell by controlling a layer lower than the radio resource control (RRC) layer. Such a cell transition may be called Lower layer triggered mobility (LTM) or L1 / L2 mobility. The layer lower than the RRC layer may be the media access control (MAC) layer or the physical (PHY) layer. Note that LTM or L1 / L2 mobility may be understood as a type of HO.

[0038] HO may be understood as a concept that includes conditional HO (CHO). CHO may be understood as an HO in which the UE200 monitors execution conditions set in advance by an RRC message (e.g., RRCReconfiguration) (e.g., the quality of the destination cell exceeds a threshold), and when those execution conditions are met, the UE200 autonomously transitions to the destination cell.

[0039] (2.2) As shown in the functional block diagram 5 of the base station, the BS100 comprises a radio signal transmitting and receiving unit 110 and a control unit 120. Note that each component of the BS100 may be understood as a distributed unit (DU) located on the UE200 side, or as a central unit (CU) located on the network side.

[0040] 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 various types of information, or may be interpreted as various types of information. 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 element (IE)) of the wireless 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).

[0041] The wireless signal transmitting / receiving unit 110 can receive the information transmitted by the wireless signal transmitting / receiving unit 210 described above. Furthermore, the wireless signal transmitting / receiving unit 110 can transmit the information received by the wireless signal transmitting / receiving unit 210 described above.

[0042] The control unit 120 controls the BS100. 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 BS100 by anticipating the operation of the UE200.

[0043] The control unit 120 can control the HO or LTM of the UE200. HO or LTM may be understood as a transition from the BS100 to which the UE200 is connected to another BS100. Alternatively, HO or LTM may be understood as a transition from the cell to which the UE200 is connected to another cell. The source and destination cells of the UE200 transition may be provided by one BS100 or by different BS100s. Note that HO or LTM may be reinterpreted as cell transition, cell change, beam change, or other terms.

[0044] (3) Parachanger Referring to FIGS. 6 and 7, the parachanger will be described. One of the purposes of the parachanger is to enable on-demand data communication in the data carrier as required. That is, the terminal can access the data carrier when data is generated, and access the parachanger otherwise. Thereby, Network Energy Saving (NES) can be realized. Note that the term "access" may be read interchangeably with terms such as "cell transition", "cell selection", and "cell reselection".

[0045] The parachanger may be understood as a carrier having at least one of the following characteristics.

[0046] - It is a carrier in a lower frequency band (e.g., 700 MHz band, 800 MHz band) compared to the data carrier (Band C shown in FIG. 6) used for transmitting and receiving user data or the anchor carrier (Band A or Band B shown in FIG. 6) used for transmitting and receiving control data. Note that control data may be transmitted and received using the data carrier, or user data may be transmitted and received using the anchor carrier.

[0047] - It is a carrier that can be accessed regardless of the presence or absence of data communication (a carrier not assuming data communication). Data communication may be understood as the transmission and reception of user data (traffic data) processed in the user plane (UP). On the other hand, data communication may be understood as the transmission and reception of control data accompanying the transmission and reception of user data.

[0048] - It is a carrier for transmitting and receiving synchronization signals (SS) and / or system information. SS may include, for example, a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). System information may include, for example, a master information block (MIB) mapped to a physical broadcast channel (PBCH) and a system information block (SIB) mapped to a physical downlink shared channel (PDSCH). Note that the signal including SS and PBCH may also be called an SS / PBCH block (SSB). Also, SIB may be, for example, SIB1.

[0049] - It is a carrier that can be accessed regardless of the type or usage environment of the terminal (however, some terminals that do not meet the conditions different from the type or usage environment may be set to be inaccessible). The type of the terminal is, for example, an enhanced Mobile BroadBand (eMBB) terminal, a Reduced Capability (RedCap) terminal, an Unmanned Aerial Vehicle (UAV) terminal, an XR terminal, an NTN terminal, an IoT terminal, an Industrial IoT terminal, a NarrowBand IoT (NB-IoT) terminal, a Low-Power Wake-Up Signal (LPWUS) terminal, a Small Data Transmission (SDT) terminal. The usage environment of the terminal is, for example, an access type (e.g., 3GPP, non-3GPP), a use case (e.g., Immersive Communication, Ubiquitous Connectivity), a service type (e.g., Ultra-Reliable and Low Latency Communications (URLLC), Vehicle to X (V2X), Multicast and Broadcast Service (MBS), Broadcast Service).

[0050] - It is a carrier that can be accessed by all terminals.

[0051] As shown in Figure 7, the system information transmitted and received on the perch carrier (the 800 MHz ellipse in the figure) may include not only system information related to the perch carrier, but also system information related to other carriers (e.g., the data carrier, the 7 GHz ellipse in the figure). In this case, only SS may be transmitted and received on the other carrier. The system information related to other carriers may be used, for example, for a UE200 that is on standby (camp on) on the perch carrier to select another carrier (to perform initial access to another carrier).

[0052] As shown in Figure 7, the SS transmitted and received on the perch carrier (the 800 MHz ellipse in the figure) may include not only SS related to the perch carrier, but also SS related to other carriers (e.g., the data carrier, the 7 GHz ellipse in the figure).

[0053] A perch carrier may also be called a perch cell or perch band. Furthermore, a perch carrier may also be called an anchor carrier or anchor band. In this case, the data carrier may be called a non-anchor carrier or non-anchor band. Note that the terms "carrier," "cell," and "band" may be used interchangeably.

[0054] A perch carrier may be recognizable by the terminal by default, or it may be configured by the network or BS100. A perch carrier may be understood as a perch carrier group consisting of multiple perch carriers.

[0055] Instead of introducing a perch carrier, the anchor carrier described above may be made to perform the function of a perch carrier. For example, Band A or Band B shown in Figure 6 may function as a perch carrier.

[0056] (4) Operation of the wireless communication system. An example of the operation of the embodiment will be described with reference to Figures 8 to 13. Figures 8 to 10 show the sequence of L3 mobility controlled by the RRC layer, and Figures 11 to 13 show the sequence of LTM controlled by a layer lower than the RRC layer. Both L3 mobility and LTM may also be called HO.

[0057] In the operation examples 1 to 3 described below, it may be assumed that the source cell of UE200 is formed by the perch carrier (or anchor carrier) described above, and the destination cell of UE200 is formed by the data carrier (or non-anchor carrier) described above. It may also be assumed that the data carrier (or non-anchor carrier) has a higher frequency band than the perch carrier (or anchor carrier). This statement does not preclude the possibility that the source cell of UE200 is formed by a perch carrier (or anchor carrier) and the destination cell of UE200 is formed by a data carrier (or non-anchor carrier). Similarly, it does not preclude the possibility that the data carrier (or non-anchor carrier) has a lower frequency band than the perch carrier (or anchor carrier), or that the frequency bands of both carriers are the same.

[0058] (4.1) Operation Example 1 An operation example of the embodiment will be described with reference to Figures 8 to 10. Figure 8 shows the sequence of HO (L3 mobility) between BS100.

[0059] Figure 8 shows the L3 mobility sequence from the source BS100A (the cell it forms) to the destination BS100B (the cell it forms). First, UE200 sends a measurement report to BS100A, including the quality of BS100B's cell (measurement report in the figure). Based on the measurement report, BS100A requests BS100B to perform a cell transition for UE200 (Handover request in the figure).

[0060] BS100B sends a message to BS100A acknowledging the cell transition of UE200 (Handover request Ack in the figure). In this embodiment, BS100B may include information about the cell formed by BS100B in the Handover request Ack (PBCH info in the figure). The cell information may include, for example, system information about the cell (e.g., MIB) and / or PBCH DMRS about the cell. Note that "system information about the cell (and / or PBCH DMRS)" may be interpreted as system information (and / or PBCH DMRS) that UE200 uses to access the cell.

[0061] BS100A sends an RRCReconfiguration to UE200 (RRCReconfiguration in the figure). RRCReconfiguration is a message from the RRC layer and may be understood as a cell transition command controlled by the RRC layer. In this embodiment, BS100A may include cell information in RRCReconfiguration (PBCH info in the figure).

[0062] Finally, upon receiving the RRCReconfiguration, UE200 transitions to the cell formed by BS100B based on the information about the cell (RRCReconfigurationComplete in the diagram).

[0063] The cell transition may also be the CHO described above. In this case, UE200, upon receiving RRCReconfiguration, monitors the execution conditions included in RRCReconfiguration (for example, that the quality of the cells formed by BS100B exceeds a threshold), and applies RRCReconfiguration if the execution conditions are met. Then, based on the information about the cells, UE200 transitions to the cells formed by BS100B.

[0064] Figure 9 shows the sequence of HO (L3 mobility) between BS100s when BS100 is composed of DU and CU. The HO shown in Figure 9 may also be called Xn HO. Figure 10 shows the sequence of HO (L3 mobility) between BS100s when BS100 is composed of DU and CU and the Xn interface has not been established. The HO shown in Figure 10 may also be called NG HO. Note that the BS100 (DU and CU) shown in Figures 9 and 10 are assumed to be applicable to NarrowBand IoT (NB-IoT), but are not limited to this.

[0065] In the Xn HO shown in Figure 9, information regarding the cells formed by BS100B may be transmitted and received, similar to Figure 8. That is, in the Xn HO, information regarding the cells may be included in the Handover request Ack transmitted from the DU of the destination BS100B to the DU of the source BS100A. Similarly, information regarding the cells may be included in the RRCReconfiguration transmitted from the DU of the source BS100A to the UE200. Note that other sequences have already been explained or are well known by referring to Figure 8, so their explanation will be omitted.

[0066] In the NG HO shown in Figure 10, information regarding the cells formed by BS100B may be transmitted and received, similar to Figure 9. That is, in the NG HO, information regarding the cells may also be included in the Handover request Ack (and HO command) transmitted from the DU of the destination BS100B to the DU of the source BS100A. The difference from Figure 9 is that the information regarding the cells is transmitted and received via AMF300. Similarly, information regarding the cells may also be included in the RRCReconfiguration transmitted from the DU of the source BS100A to UE200. Note that other sequences have already been explained or are well known with reference to Figure 8, so their explanation will be omitted.

[0067] (4.2) Operation Example 2 An operation example of the embodiment will be described with reference to Figures 11 to 13. Figure 11 shows the sequence of LTM (Intra-CU LTM) between DUs provided by BS100. The DU from which the transition begins is also called the source DU, and the DU to which the transition ends is also called the target DU. For details of the messages shown in Figure 11, please refer to, for example, TS 38.401 section 8.2.1.

[0068] Figure 11 shows the LTM sequence from the source DU (the cell it forms) to the target DU (the cell it forms) provided by BS100. As a prerequisite, UE200 transmits measurement reports to BS100, including the quality of the cells formed by the target DU (L3 measurement control and reports in the figure). Based on these measurement reports, the CU in BS100 decides to initiate the LTM configuration (LTM configuration decision in the figure).

[0069] The CU sends a UE context setup request to the target DU and receives a UE context setup response from the target DU. Here, the target DU in this embodiment may include information about the cell formed by the target DU in the UE context setup response (PBCH info in the figure). The cell information may include, for example, system information about the cell (e.g., MIB) and / or PBCH DMRS about the cell. Note that "system information about the cell (and / or PBCH DMRS)" may be interpreted as system information (and / or PBCH DMRS) that the UE200 uses to access the cell.

[0070] The CU sends a UE context modification request to the source DU and receives a UE context modification response from the source DU.

[0071] The CU sends a UE context modification request to the target DU and receives a UE context modification response from the target DU. In this embodiment, the target DU may include information about the cell in the UE context modification response (PBCH info in the figure).

[0072] The CU sends a DL RRC message transfer to the target DU, and the target DU sends an RRCReconfiguration to the UE200. Here, the target DU of this embodiment may include cell information in the UE context modification response (PBCH info in the figure). Similarly, the source DU of this embodiment may include cell information in the RRCReconfiguration (PBCH info in the figure). Unlike in operation example 1, the RRCReconfiguration in operation example 2 does not necessarily have to be understood as a cell transition command.

[0073] Upon receiving an RRCReconfiguration, UE200 sends RRCReconfigurationComplete to CU via the source DU. When the source DU receives the L1 measurement report from UE200, it determines the cell transition and sends a cell switch command to UE200. The cell switch command is a MAC layer control element (MAC CE) and may be understood as a cell transition command controlled by a lower layer than the RRC layer. In this embodiment, the source DU may include the cell information described above in the cell switch command (PBCH info in the figure). The source DU notifies the target DU of the cell change via the CU (DU CU cell switch notification and CU DU cell switch notification in the figure).

[0074] Finally, upon receiving the cell switch command, the UE200 transitions to the cell formed by the target DU based on the information about the cell (RRCReconfigurationComplete in the diagram). If the RRCReconfiguration contains multiple pieces of information about the cell (i.e., there are multiple candidate cells that could be the destination cell), the UE200 can identify the information about the destination cell from among the information about the multiple cells based on the config ID of the destination cell (target config ID) included in the cell switch command, and then transition to that cell.

[0075] Figure 12 shows the sequence of LTMs (Inter-CU LTMs) between BS100s (BS100A, BS100B). The Inter-CU LTMs shown in Figure 12 may also be called Xn LTMs. Figure 13 shows the sequence of LTMs (Inter-CU LTMs) between BS100s (BS100A, BS100B) where the Xn interface has not been established. The Inter-CU LTMs shown in Figure 13 may also be called NG LTMs. Note that the BS100s (DU and CU) shown in Figures 12 and 13 are assumed to be applicable to NarrowBand IoT (NB-IoT), but are not limited to this.

[0076] In the Xn LTM shown in Figure 12, information regarding the cells formed by BS100B may be transmitted and received, similar to Figure 11. That is, in the Xn LTM, information regarding the cells may be included in the Handover request Ack (or LTM request Ack) sent from the DU of the destination BS100B to the DU of the source BS100A. Similarly, information regarding the cells may be included in the RRCReconfiguration sent from the DU of the source BS100A to the UE200. Also, similar to Figure 11, information regarding the cells may be included in the cell switch command sent from the DU of the source BS100A to the UE200. Note that other sequences have already been explained or are well known by referring to Figure 11, so their explanation will be omitted.

[0077] In the NG LTM shown in Figure 13, information regarding the cells formed by BS100B may be transmitted and received, similar to Figure 12. That is, in the NG LTM as well, information regarding the cells may be included in the Handover request Ack (and HO command) transmitted from the DU of the destination BS100B to the DU of the source BS100A. The difference from Figure 12 is that information regarding the cells is transmitted and received via AMF300. Similarly, information regarding the cells may be included in the RRCReconfiguration transmitted from the DU of the source BS100A to the UE200. Also, similar to Figure 12, information regarding the cells may be included in the cell switch command transmitted from the DU of the source BS100A to the UE200. Note that other sequences have already been explained or are well known by referring to Figure 11, so their explanation will be omitted.

[0078] (4.3) Operation Example 3 Operation Example 3 is a modification of Operation Example 2. Therefore, Operation Example 3 will be explained with reference to Figure 11. In Figure 11, UE200 may transition from the source cell to a cell that transmits information about the cell formed by BS100B (hereinafter referred to as a parchment cell for convenience of explanation) before receiving the cell switch command. UE200 may then transition to a cell formed by BS100B after receiving information about the cell in the parchment cell.

[0079] Thus, in operation example 3, UE200 can receive information about the cell via a parchment cell instead of going through the source BS100A (and the cell it forms).

[0080] (5) Effects and Functions According to the embodiments described above, even in situations where no information about the destination cell (for example, a cell formed by a data carrier) is transmitted or received in the destination cell, the UE200 can obtain information about the destination cell from the source cell (for example, a cell formed by a parch carrier), and thus can perform cell transitions as before.

[0081] (6) 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.

[0082] The examples of operation described above may be combined and applied in combination, as long as no inconsistencies arise.

[0083] 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.

[0084] 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.

[0085] 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 14 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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).

[0093] 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).

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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).

[0098] 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.

[0099] 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).

[0100] 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.

[0101] 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.

[0102] 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, a comparison with a predetermined value).

[0103] 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).

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] The terms “system” and “network” as used in this disclosure are interchangeable.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] In this disclosure, terms such as “terminal,” “user terminal,” “Mobile Station (MS),” and “User Equipment (UE)” may be used interchangeably.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] Figure 15 shows an example of the configuration of vehicle 2001. As shown in Figure 15, 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.

[0120] The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor.

[0121] 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.

[0122] 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).

[0123] 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.

[0124] 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.

[0125] 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.).

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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).

[0131] 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.

[0132] 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."

[0133] 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.

[0134] The reference signal may also be abbreviated as RS, and may be called Pilot depending on the applicable standard.

[0135] 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."

[0136] 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.

[0137] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] One or more RBs may also be called Physical RBs (PRBs), Sub-Carrier Groups (SCGs), Resource Element Groups (REGs), PRB pairs, RB pairs, etc.

[0153] 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.

[0154] 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.

[0155] 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".

[0156] 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.

[0157] 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.

[0158] 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.

[0159] 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."

[0160] 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.

[0161] (Note) The disclosure described above may also be expressed as follows:

[0162] The first feature is that the terminal may include a receiving unit that receives information from a first cell formed by a first carrier about a second cell formed by a second carrier having a higher frequency band than the first carrier, and a control unit that performs a transition from the first cell to the second cell based on the information about the second cell.

[0163] The second feature is that, in the first feature, the receiving unit may be a terminal that receives a cell transition command containing information about the second cell.

[0164] A third feature is that, in the first or second feature, the control unit may be a terminal that performs the transition from the first cell to the second cell by controlling the wireless resource control layer.

[0165] A fourth feature is that, in the first or second feature, the control unit may be a terminal that performs the transition from the first cell to the second cell by controlling a layer lower than the wireless resource control layer.

[0166] A fifth feature is that, in any of the first to fourth features, the receiving unit may be a terminal that receives system information relating to the second cell as information relating to the second cell.

[0167] The sixth feature is that, in any of the first to fifth features, the receiving unit may be a terminal that receives a physical broadcast channel demodulation reference signal relating to the second cell as information relating to the second cell.

[0168] 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 information from a first cell formed by a first carrier about a second cell formed by a second carrier having a higher frequency band than the first carrier; and a control unit that performs a transition from the first cell to the second cell based on the information about the second cell.

2. The terminal according to claim 1, wherein the receiving unit receives a cell transition command that includes information relating to the second cell.

3. The terminal according to claim 1, wherein the control unit performs a transition from the first cell to the second cell by controlling the wireless resource control layer.

4. The terminal according to claim 1, wherein the control unit performs the transition from the first cell to the second cell by controlling a layer lower than the wireless resource control layer.

5. The terminal according to claim 1, wherein the receiving unit receives system information relating to the second cell as information relating to the second cell.

6. The terminal according to claim 1, wherein the receiving unit receives a physical broadcast channel demodulation reference signal relating to the second cell as information relating to the second cell.

Images