Terminal device, base station device, and communication system
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-06
- Publication Date
- 2026-08-13
Smart Images
Figure JP2025003948_13082026_PF_FP_ABST
Abstract
Description
Terminal equipment, base station equipment, and communication systems
[0001] This disclosure relates to terminal equipment, base station equipment, and communication systems.
[0002] Currently, mobile device traffic (smartphones and feature phones) accounts for the majority of network resources. Furthermore, mobile device traffic is expected to continue expanding. Beyond mobile device traffic, IoT (Internet of Things) services (e.g., transportation systems, smart meters, and monitoring systems for equipment) are also being deployed. Therefore, networks are required to accommodate services with diverse requirements. To accommodate such diverse services, the communication standards for fifth-generation mobile communications (5G or NR (New Radio)) (for example, Non-Patent Documents 1-14) are formulated to support many use cases classified as eMBB (Enhanced Mobile Broadband), Massive MTC (Machine Type Communication), and URLLC (Ultra Reliable and Low Latency Communication), in addition to the standard technologies of 4G (fourth-generation mobile communications).
[0003] Furthermore, extensions to the above communication standards are still being considered and standardized in the working group of the Third Generation Partnership Project (3GPP), an international standardization project.
[0004] For example, the 3GPP working group considered LTM (Low-layer Triggered Mobility) technology, and LTM was introduced in Release 18.
[0005] 3GPP TS 37.324 V18.0.03GPP TS 37.340 V18.4.03GPP TS 38.201 V18.0.03GPP TS 38.202 V18.4.03GPP TS 38.211 V18.5.03GPP TS 38.212 V18.5.03GPP TS 38.213 V18.5.03GPP TS 38.214 V18.5.03GPP TS 38.215 V18.4.03GPP TS 38.300 V18.4.03GPP TS 38.321 V18.4.03GPP TS 38.322 V18.2.03GPP TS 38.323 V18.4.03GPP TS 38.331 V18.4.0
[0006] The LTM introduced in Release 18, for example, triggers a cell switch at the physical layer of the terminal device. Furthermore, for the LTM introduced in Release 18, the terminal device performs channel measurements of candidate cells for cell switching using SSB (Synchronization Signal / PBCH block). However, channel measurements using SSB have a wider beam width than channel measurements using CSI-RS (Channel State Information - Reference Signal). Therefore, the terminal device cannot recognize the CSI after a Cell Switch has been performed in response to the SSB channel measurement. If the CSI cannot be recognized, the terminal device may not be able to correctly configure settings such as MCS (Modular Code Scheme) or MIMO (Multi-input Multi-output), which is likely to reduce throughput. Therefore, throughput after Cell Switch may decrease in LTM.
[0007] The disclosed technology, made in view of the above, provides a method for enabling channel measurement in LTM that can reduce the possibility of throughput degradation after Cell Switch.
[0008] One aspect provides a terminal device comprising: a receiving unit that receives a first signal via a first cell containing configuration information for measuring a second signal transmitted from a second cell different from the first cell, and receives a fourth signal via the first cell instructing a switch from the first cell to the second cell; and a control unit that, if it has received a third signal containing instruction information instructing the transmission of measurement information, controls the device to transmit the measurement information via the second cell after receiving the fourth signal.
[0009] In LTM, it becomes possible to provide terminal equipment, base station equipment, and communication systems that can reduce the possibility of throughput degradation after Cell Switch.
[0010] Figure 1 shows an example of a wireless communication system in Embodiment 1. Figure 2 shows an example of a functional configuration diagram of a base station device. Figure 3 shows an example of a functional configuration diagram of a terminal device. Figure 4 shows an example of a slot configuration. Figure 5 shows an example of the relationship between value μ, slot, frame, and subframe. Figure 6 shows an example of LTM Cell Switch processing in the MAC layer of terminal device 200. Figure 7 shows an example of a cell switching procedure in an embodiment. Figure 8 shows an example of a CSI acquisition method in Embodiment 1. Figure 9 shows an example of a CSI acquisition method in Embodiment 2. Figure 10 shows an example of a hardware configuration of a base station device. Figure 11 shows an example of a hardware configuration of a terminal device.
[0011] Hereinafter, this embodiment will be described in detail with reference to the drawings. The problems and embodiments described herein are examples and do not limit the scope of the rights of this application. In particular, even if the wording of the description is different, if it is technically equivalent, the technology of this application can be applied even with different wording and does not limit the scope of the rights. Furthermore, each embodiment can be combined as appropriate, as long as the processing content is not contradictory.
[0012] Furthermore, the terminology and technical content used in this specification may be appropriately adapted from the terminology and technical content described in specifications and contributions of communication standards such as 3GPP. Examples of such specifications are those described in Non-Patent Documents 1 to 14.
[0013] The embodiments of the base station equipment, terminal, and communication system (wireless communication system) disclosed in this application will be described in detail below with reference to the drawings. The following embodiments are not intended to limit the disclosed technology. Embodiment 1
[0014] Figure 1 shows an example of a wireless communication system 1 in Embodiment 1. The wireless communication system 1 includes a base station device 100A, a base station device 100B, a terminal device 200A, a terminal device 200B, and a terminal device 200C. Base station device 100A forms cell C10. Base station device 100B forms cell C11. The terminal devices 200 are located within the coverage of at least one base station device 100. Hereinafter, when base station device 100A and base station device 100B are not distinguished, they will simply be referred to as base station device 100. Similarly, when terminal devices 200A, terminal device 200B, and terminal device 200C are not distinguished, they will simply be referred to as terminal device 200.
[0015] Cell C10 may be referred to as the coverage of base station equipment 100A. Similarly, cell C11 may be referred to as the coverage of base station equipment 100B.
[0016] Furthermore, the base station device 100 may be a small wireless base station device (including micro wireless base station devices and femto wireless base station devices, etc.), such as a macro wireless base station device or a pico wireless base station device, or a wireless base station device of various sizes, and may be described as a wireless communication device, a communication device, a transmitting device, etc. Also, the terminal device 200 may be a wireless terminal such as a mobile phone, a smartphone, a PDA (Personal Digital Assistant), a personal computer, or various devices and equipment (sensor devices, etc.) with wireless communication functions, such as a vehicle, and may be described as a wireless communication device, a communication device, a receiving device, a mobile station, etc.
[0017] The base station device 100 is connected to the network via a wired connection with network devices (higher-level devices and other base station devices) not shown in the diagram. Alternatively, the base station device 100 may be connected to the network devices wirelessly instead of via a wired connection.
[0018] The base station device 100 may separate its wireless communication function with the terminal device 200 from its digital signal processing and control functions into separate devices. In this case, the device with wireless communication functionality can be called an RRH (Remote Radio Head), and the device with digital signal processing and control functions can be called a BBU (Base Band Unit). The RRH may be installed extending from the BBU, and these devices may be connected by a wired connection such as an optical fiber, or by a wireless connection. Furthermore, the base station device 100 may not only be separated as described above as the RRH and BBU, but may also be separated into, for example, a CU (Central Unit), a DU (Distributed Unit), and a RU (Radio Unit). The CU may include, for example, the functions of the RRC (Radio Resource Control) layer. Furthermore, the CU includes, for example, the functionality of the PDCP (Packet Data Convergence Protocol) layer. The CU also includes, for example, the functionality of the SDAP (Service Data Adaptation Protocol) layer. The DU includes, for example, the functionality of the MAC (Media Access Control) layer. The DU may also include, for example, the functionality of the RLC (Radio Link Control) layer. The RU includes at least an RF radio circuit. The DU and RU may be configured as an integrated unit.
[0019] Meanwhile, the terminal device 200 communicates with the base station device 100 via wireless communication.
[0020] Furthermore, if an RRC (Radio Resource Control) connection has not been established between the base station device 100 and the terminal device 200, the base station device 100 will perform a process to establish an RRC connection. The process to establish an RRC connection may include a random access procedure.
[0021] Next, the base station device 100 will be described. Figure 2 is a diagram showing an example of the functional configuration of the base station device 100 in this embodiment. The base station device 100 includes a wireless communication unit 110, a control unit 120, a storage unit 130, and a communication unit 140.
[0022] The wireless communication unit 110 consists of a transmitting unit 111 and a receiving unit 112, and communicates wirelessly with the terminal device 200. Specifically, the transmitting unit 111 transmits data signals and control signals wirelessly via an antenna. The antenna may be the same for both transmitting and receiving. The transmitting unit 111 transmits downlink signals to the terminal device 200, such as random access procedure signals, downlink physical signals, RRC layer signals, downlink data signals, and downlink control signals.
[0023] Furthermore, the receiving unit 112 can receive uplink signals transmitted from the terminal device 200, such as random access procedure signals, RRC layer signals, uplink data signals, and uplink control signals.
[0024] The control unit 120 controls the base station device 100. Specifically, the control unit 120 can control the establishment of an RRC connection with the terminal device 200, signal processing of signals received by the receiving unit 212, creation of transmission blocks (TB: Transport Block), and mapping of transmission blocks to radio resources. The control unit 120 can also perform LTM-related controls. For example, the control unit 120 controls the transmission of a signal instructing the measurement of the measurement signal for the cell switching destination via the transmission unit 111.
[0025] The memory unit 130 can store, for example, downlink data signals.
[0026] The communication unit 140 connects to a network device (for example, a host device or another base station device) via wired or wireless connection and performs communication. Data signals received by the communication unit 140 for the terminal device 200 can be stored in the storage unit 130.
[0027] Next, the terminal device 200 will be described. FIG. 3 is a diagram showing an example of the functional configuration of the terminal device 200 in the present embodiment. As shown in FIG. 3, the terminal device 200 includes a communication unit 210, a control unit 220, and a storage unit 230. These components are connected so that signals and data can be input and output in one direction or two directions. Note that the communication unit 210 can be described separately as a transmission unit 211 and a reception unit 212.
[0028] The transmission unit 211 transmits data signals and control signals by wireless communication via an antenna. Note that the antenna may be common for transmission and reception. The transmission unit 211 transmits, for example, signals of an uplink such as a random access procedure signal, an RRC layer signal, an uplink data signal, and an uplink control signal.
[0029] The reception unit 212 receives downlink signals such as, for example, a random access procedure signal, a downlink data signal, and a downlink control signal transmitted from the base station device 100. Further, the received signal may include a reference signal used for, for example, channel estimation and demodulation.
[0030] The control unit 220 controls the terminal device 200. Specifically, the control unit 220 can control the establishment of an RRC connection with the base station device 100, signal processing of the signal received by the reception unit 212, creation of a transmission block (TB), and mapping of the transmission block to radio resources. Further, the control unit 220 controls so as to perform control related to LTM. For example, the control unit 220 measures a measurement signal transmitted from the base station device 100B of the cell switching destination and controls to report the measurement result to the base station device 100A.
[0031] The storage unit 230 can store, for example, an uplink data signal. Further, the storage unit 230 can store configuration information (or setting information) related to wireless communication transmitted from the base station device 100. Note that the configuration information is, for example, CSI-RS resource or report configuration information, and information related to LTM.
[0032] Note that the communication unit 110 of the base station apparatus 100 and the communication unit 210 of the terminal apparatus 200 may be configured to include antenna ports.
[0033] The uplink may be referred to as an uplink (UpLink). The downlink may be referred to as a downlink (DownLink). The uplink may be a communication link (Communication Link) through which the terminal apparatus 200 transmits to the base station apparatus 100. The downlink may be a communication link through which the base station apparatus 100 transmits to the terminal apparatus 200.
[0034] The uplink channel may include some or all of PUSCH (Physical Uplink Shared Channel), PUSCH (Physical Uplink Control Channel), PRACH (Physical Random Access Channel), and SRS (Sounding Reference Signal).
[0035] The uplink signal may be a signal transmitted via PUSCH, PUCCH, PRACH, and SRS.
[0036] The downlink channel may include some or all of PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), PBCH (Physical Broadcast Channel), SSB (Synchronization Signal Block), and CSI-RS (Channel State Information - Reference Signal).
[0037] The downlink signal may be a signal transmitted via PDSCH, PDCCH, and PBCH. The downlink signal may include a downlink reference signal (Downlink Reference Signal). SSB may be an SS (Synchronization Signal) / PBCH block.
[0038] The higher-level parameters may include some or all of the parameters of the RRC parameters, MAC CE (Media Access Control Control Element), SIB (System Information Block), and MIB (Master Information Block).
[0039] Here, we will describe an example of slots for the base station device 100 and terminal device 200 to perform wireless communication.
[0040] Figure 4 shows an example of the slot configuration in this embodiment. The radio frame shown in Figure 4 may be, for example, 10 milliseconds (msec). The radio frame may also be referred to as a frame. Furthermore, the radio frame may also be referred to as a system frame. In addition, the radio frame is composed of, for example, 10 subframes.
[0041] In the wireless frame shown in Figure 4, for example, the length of the time axis of the wireless frame is determined according to the subcarrier spacing (SCS). For example, the subcarrier spacing is SCS = 15 × 2 μ It is determined by the relationship (kHz). In other words, μ = 0 means that the subcarrier spacing is 15 kHz. In the following, μ may be referred to as the value μ or the value μ that determines the subcarrier spacing.
[0042] In 15 kHz subcarrier spacing, a single frame may contain 10 slots. Each slot may contain, for example, 14 OFDM symbols. An OFDM symbol may consist of, for example, multiple physical resource blocks. Each physical resource block may consist of, for example, 12 subcarriers.
[0043] Note that the slot is defined, for example, using subcarrier spacing μ, n ｓμ is numbered. n ｓ μ For example, in one subframe, it is numbered in ascending order within the range of {0, 1, 2, ···, N ｓｌｏｔ subframe, μ - 1}. n ｓ μ For example, in one frame, it is numbered in ascending order (Increasing order) within the range of {0, 1, 2, ···, N ｓｌｏｔ ｆｒａｍｅ、μ - 1}. One slot may include N ｓｙｍｂ ｓｌｏｔ OFDM symbols. N ｓｙｍｂ ｓｌｏｔ may have different values depending on the length of the Cyclic Prefix (CP: Cyclic Prefix).
[0044] Fig. 5 is a diagram showing an example of the relationship between the value μ, slot, frame, and subframe in the present embodiment. Note that Normal CP may be adopted for all values of μ. Also, at μ = 2, Extended CP may be adopted. The length of the CP in the time domain may be shorter for Normal CP than for Extended CP. Fig. 5 also shows an example of the number of slots N included in one radio frame for the value μ ｓｌｏｔ ｆｒａｍｅ、μ and an example of the number of slots included in one subframe for the value μ. In the case of Normal CP, for example, one slot includes 14 OFDM symbols. In the case of Extended CP, for example, one slot includes 12 OFDM symbols. In the present embodiment, unless otherwise specified, it is assumed to be Normal CP. Note that the technology in the present embodiment can be applied to Normal CP and Extended CP.
[0045] Note that the subcarrier spacing may be called Numerology. Different Numerology may mean different subcarrier spacings.
[0046] A time resource may be one or more OFDM symbols. A time resource may be one or more slots. A time resource may be one or more system frames.
[0047] The frequency resource may be one or more subcarriers. The frequency resource may be one or more PRBs.
[0048] The channel on which a symbol is transmitted on a given antenna port may be defined as being able to infer the channels on which other symbols are transmitted on the same antenna port. In other words, multiple symbols transmitted on the same antenna port at different time instances can be considered to have been transmitted on the same channel.
[0049] If the Large Scale property of a channel on one antenna port from which a certain symbol is transmitted allows for the inference of a channel on the other antenna port from which a different symbol is transmitted, then the two antenna ports may be said to be a QCL (Quasi Co-Location). The Large Scale property may include one or more delay spreads, Doppler spreads, Doppler shifts, average gains, average delays, and some or all of the spatial reception parameters.
[0050] In each Numerology and carrier, the resource grid is N ｇｒｉｄ，ｘ ｓｉｚｅ，μ ×N ｓｃ ＲＢ Individual subcarriers and N ｓｙｍｂ The subframe may be defined by μ OFDM symbols. ｓｃ ＲＢ It may be 12.
[0051] FR1 (Frequency Range 1) may have a carrier frequency of less than 6 GHz. FR2 may have a carrier frequency of 6 GHz or higher.
[0052] TDD (Time Division Duplex) may also be referred to as unpaired spectrum.
[0053] A random access preamble sequence supports one or more different lengths. The lengths of a random access preamble sequence may include 139, 571, 839, or 1151.
[0054] A random access preamble sequence of length 839 may be applied to part or all of a 1.25 kHz and / or 5 kHz SCS. A random access preamble sequence of length 139 may be applied to SCSs of 15 kHz, 30 kHz, 60 kHz, 120 kHz, 480 kHz, and 960 kHz. A random access preamble sequence of length 571 may be applied to part or all of a 30 kHz and / or 120 kHz and / or 480 kHz SCS. A random access preamble sequence of length 1151 may be applied to part or all of a 15 kHz and / or 120 kHz SCS.
[0055] Next, TDD will be described. In TDD, the base station device 100 may determine the slot format. In TDD, the base station device 100 may transmit slot format configuration information to the terminal device 200. The terminal device 200 may determine the slot format based on the slot format configuration information. The base station device 100 may store the slot formats of the terminal devices 200 in the cell included in the base station device 100. The slot format configuration information may consist of one or more upper-layer parameters or one or more physical layer signals.
[0056] In a downlink slot and / or downlink symbol, the terminal device 200 may receive downlink channels and / or downlink signals. For example, the terminal device 200 may receive PDSCH, PDCCH, PBCH, CSI-RS, or SSB in a downlink slot and / or downlink symbol. In an uplink slot and / or uplink symbol, the terminal device 200 may receive uplink channels and / or uplink signals. For example, the terminal device 200 may transmit PUSCH, PUCCH, PRACH, or SRS in an uplink slot and / or uplink symbol. In a flexible slot and / or flexible symbol, the terminal device 200 may receive downlink channels or downlink signals scheduled in DCI format. In a flexible slot and / or flexible symbol, the terminal device 200 may transmit uplink channels or uplink signals scheduled in DCI format. In the flexible slot and / or flexible symbol, the terminal device 200 may transmit PRACH.
[0057] In a set of symbols for a slot that is indicated to be flexible by tdd-UL-DL-ConfigurationCommon and / or tdd-UL-DL-ConfigurationDedicated, if the terminal device 200 is not configured to monitor PDCCH in DCI format 2_0, or if tdd-UL-DL-ConfigurationCommon and / or tdd-UL-DL-ConfigurationDedicated is not provided to the terminal device 200, if the terminal device 200 receives a corresponding instruction in DCI format, the terminal device 200 may receive PDSCH or CSI-RS in the set of symbols for the slot.
[0058] A terminal device 200 configured to operate on a serving cell's Bandwidth Part (BWP) may have up to four sets of BWPs configured by the higher layer of the serving cell. These sets of BWPs may include uplink BWPs (UL BWPs) and downlink BWPs (DL BWPs). DL BWPs may be used by the terminal device 200 for reception in the downlink bandwidth. DL BWP may be configured based on the upper layer parameter BWP-Downlink, or based on the upper layer parameter initialDownlinkBWP using a set of parameters configured by the upper layer parameters tdd-UL-DL-ConfigurationCommon and / or tdd-UL-DL-ConfigurationDedicated. UL BWP may be used by the terminal device 200 for transmission in the uplink bandwidth. UL BWP may be configured based on the upper layer parameter BWP-Uplink, or it may be configured based on the upper layer parameter initialUplinkBWP, which uses a set of parameters consisting of the upper layer parameters BWP-UplinkCommon and / or BWP-UplinkDedicated.
[0059] The terminal device 200 may transmit the uplink channel and / or uplink signal in UL BWP. The terminal device 200 may receive the downlink channel and / or downlink signal in DL BWP.
[0060] The serving cell may be the cell to which the terminal device 200 is connected. The candidate cell may be a cell that could potentially be the cell to which the terminal device 200 switches. In addition, one or more candidate cells may be set in the terminal device 200. The target cell may be a cell included in the cell switching instruction. The target cell may also be the cell to which the terminal device 200 switches. Cell switching may be referred to as LTM cell switch.
[0061] Here, we will explain the LTM processing flow.
[0062] The terminal device 200 may be indicated by the upper-layer parameter LTM-Config to specify one or more candidate cells and one or more SSBs for each of those candidate cells. The SSBs may be indicated for the terminal device 200 to acquire synchronization and / or to measure some or all of the one or more L1-RSRPs and / or L1-SINRs corresponding to the SSBs. The terminal device 200 may also be indicated by the upper-layer parameter LTM-Config to specify one or more candidate cells and one or more CSI-RSs for each of those candidate cells. The CSI-RSs may be indicated for the terminal device 200 to acquire synchronization and / or to measure some or all of the one or more L1-RSRPs and / or L1-SINRs using the CSI-RSs.
[0063] The LTM Cell Switch Command MAC CE may be a command that instructs the terminal device 200 to switch cells. The LTM Cell Switch Command MAC CE may also be referred to as CSC (Cell Switch Command). The Serving cell may transmit the CSC to the terminal device 200. When the terminal device 200 receives the CSC, the terminal device 200 may perform a cell switch based on the information contained in the CSC.
[0064] L1-RSRP (Layer1-Reference Signal Received Power) may be the received power of the reference signal received by the terminal device 200. L1-RSRP may also be a value indicating radio wave strength. L1-SINR (Layer1-Signal to Interference plus Noise power ratio) may be the ratio of the power of the desired signal to the power of signals other than the desired signal.
[0065] The TCI state activation / deactivation MAC CE command for a candidate cell may activate and / or deactivate the TCI state provided by the higher-level parameters Candidate-TCI-State-r18 and / or Candidate-TCI-UL-State-r18 in the candidate cell. The TCI state may be associated with the SSB or TRS of the corresponding candidate cell.
[0066] If a candidate cell's TCI state activation or deactivation MAC CE command activates one or more TCI states, the LTM Cell Switch Command MAC CE may instruct one TCI state from among the activated one or more TCI states. If a candidate cell's TCI state activation or deactivation MAC CE command does not activate one or more TCI states, the LTM Cell Switch Command MAC CE may instruct to activate one TCI state from among the one or more TCI states provided by the higher-level parameters Candidate-TCI-State-r18 and / or Candidate-TCI-UL-State-r18.
[0067] After receiving an LTM Cell Switch Command MAC CE from the base station device 100, the terminal device 200 may deactivate TCI states other than the TCI state instructed by the LTM Cell Switch Command MAC CE.
[0068] The terminal device 200 may provide report configuration information for reporting L1-RSRP measurement results via the upper-layer parameter LTM-CSI-ReportConfigToAddModList. The report configuration information may include the number of candidate cells and the number of SSBs and / or CSI-RSs for each candidate cell contained within the candidate cells.
[0069] If, in one candidate cell, the upper layer parameter ltm-UE-MeasuredTA-ID and / or the upper layer parameter ltm-ServingCellUE-MeasuredTA-ID of the serving cell are provided to the terminal device 200, and the two upper layer parameters have the same value, the terminal device 200 may estimate a Timing Advance to apply to the first transmission on the candidate cell after receiving an LTM Cell Switch Command MAC CE instructing a cell switch to the candidate cell, provided that predetermined conditions are met.
[0070] The terminal device 200 may be provided with parameters for PRACH transmission in one or more candidate cells by the upper-layer parameter EarlyUL-SyncConfig. The terminal device 200 may be triggered by a PDCCH Order to perform PRACH transmission in a candidate cell. The terminal device 200 may receive the PDCCH Order from the serving cell. The PDCCH Order may also include an indication of which candidate cell will perform the PRACH transmission.
[0071] The PDCCH Order may also be an instruction from the base station device 100 to the terminal device 200 to transmit a PRACH using a PDCCH that includes a DCI. The DCI may include information about candidate cells to which the PRACH is to be transmitted.
[0072] If the serving cell and the candidate cell are operating in the same frequency band, and the terminal device 200 performs uplink transmissions that overlap in time to both cells, and the terminal device 200 does not support uplink transmissions that overlap in time, the terminal device 200 does not need to transmit on the serving cell.
[0073] If the serving cell and the candidate cell are operating in the same frequency band, and the terminal device 200 performs uplink transmissions that overlap in time to both cells, and the terminal device 200 supports uplink transmissions that overlap in time, the terminal device 200 may prioritize the power allocation of PRACH transmissions on the candidate cell.
[0074] If the serving cell and the candidate cell are operating in the same frequency band, and the terminal device 200 makes uplink transmissions that overlap in time to both cells, and the gap between the uplink transmissions of the candidate cell and the serving cell is less than N symbols, then the terminal device 200 does not need to transmit on the serving cell. The gap may be the number of symbols between the last symbol of the uplink transmission in the serving cell and the first symbol of the PRACH transmission in the candidate cell. The gap may also be the number of symbols between the last symbol of the PRACH transmission in the candidate cell and the first symbol of the uplink transmission in the serving cell.
[0075] If the serving cell and the candidate cell are operating in the same frequency band, and the terminal device 200 performs uplink transmissions that overlap in time with both cells, and the interval between the uplink transmissions of the candidate cell and the serving cell is less than N symbols, and the total transmission power of the terminal device 200 in the frequency band in which the uplink transmissions are performed exceeds the upper limit, the terminal device 200 may prioritize the power allocation for PRACH transmissions on the candidate cell.
[0076] The terminal device 200 may transmit PRAC to the candidate cell with a predetermined transmission power.
[0077] The terminal device 200 may, in a serving cell, be provided by the CSC included in the PDSCH reception with the upper layer parameter CandidateTCI-State, which is included in the upper layer parameter ltm-DL-OrJointTCI-StateToAddModList, and / or the upper layer parameter CandidateTCI-UL-State, which is included in the upper layer parameter ltm-UL-TCI-StateToAddModList. The upper layer parameter CandidateTCI-State, and / or CandidateTCI-UL-State, may indicate a TCI state applicable to uplink transmission and / or downlink reception in one candidate cell from among one or more candidate cells. The one candidate cell may be determined by the CSC. The one candidate cell may be indicated by the CSC. The single candidate cell may be referred to as the Target cell.
[0078] The terminal device 200 may assume that one or more DMRS antenna ports for PDCCH reception and PDSCH reception are SSB, TRS, and / or CSI-RS and QCL included in the TCI state. The QCL may have attributes of type A and / or type D.
[0079] The terminal device 200 does not need to expect QCL Type A to be notified when the SSB is configured as the source reference signal for the TCI state.
[0080] When CandidateTCI-State and / or CandidateTCI-UL-State are provided to terminal device 200 by CSC, terminal device 200 transmits a HARQ-ACK corresponding to the PDSCH reception containing CSC, starting from the last symbol of PUCCH or PUSCH, T ＬＴＭ－ＲＲＣ－ｐｒｏｃｅｓｓｉｎｇ +T ＬＴＭ－ｐｒｏｃｅｓｓｉｎｇ +T ｆｉｒｓｔ－ＲＳ +TＲＳ－ｐｒｏｃ CandidateTCI-State and / or CandidateTCI-UL-State may be applied within +3 msec. Here, T ＬＴＭ－ＲＲＣ－ｐｒｏｃｅｓｓｉｎｇ This may be the time required for decoding the RRC configuration information of the LTM target cell as instructed by the CSC and for validity and / or compliance checks. ＬＴＭ－ｐｒｏｃｅｓｓｉｎｇ This may be the processing time on the terminal device side, consisting of applying target cell parameters and L1 / L2 changes. ｆｉｒｓｔ－ＲＳ This is the time for fine-time tracking and obtaining complete timing information for the target cell. ＲＳ－ｐｒｏｃ msec may be the SSB processing time. msec may be 1 / 1000 of a second. For example, 3 msec in this case is 3 / 1000 of a second.
[0081] In the case of RACH-based LTM, the terminal device 200 may apply CandidateTCI-State to reception on the candidate cell and apply a spatial domain filter corresponding to CandidateTCI-State or CandidateTCI-UL-State to transmission on the candidate cell from the completion of the random access procedure related to PRACH transmission on the candidate cell until a new TCI state is instructed for the candidate cell.
[0082] In the case of RACH-less LTM, the terminal device 200 may apply CandidateTCI-State to receptions on candidate cells and apply a spatial filter corresponding to CandidateTCI-State or CandidateTCI-UL-State to transmissions on candidate cells until a new TCI state is instructed for the candidate cell.
[0083] The base station device 100 may also notify the terminal device 200 that it will execute the LTM cell switch procedure by transmitting a CSC. This notification may be made by a MAC entity.
[0084] Figure 6 shows an example of LTM cell switch processing in the MAC layer of terminal device 200. The serving cell is assumed to belong to base station device 100. The MAC layer may also include a MAC entity that performs processing in the MAC layer. The lower layer, MAC layer, and / or upper layer may be included in part or all of the terminal device 200. The lower layer may be the physical layer. The upper layer and / or MAC layer may be included in the upper layer. The lower layer, MAC layer, and upper layer may be included in terminal device 200. The lower layer, MAC layer, and upper layer may be included in base station device 100. The lower layer, MAC layer, and upper layer shown in Figure 6 may be implemented, for example, according to the control of the control unit 220.
[0085] The lower layer of the terminal device 200 receives the CSC included in the PDSCH transmitted via the serving cell (step S10). The lower layer of the terminal device 200 then notifies the MAC layer of the received CSC (step S11).
[0086] When the MAC layer of terminal device 200 receives the CSC, it instructs or notifies the upper layer of terminal device 200 that a cell switch has been triggered and provides the Target Configuration ID contained in the CSC (step S12). The Target Configuration ID may include the cell index that is the target of the cell switch.
[0087] The MAC layer of terminal device 200 receives instructions or notifications regarding MAC processing from the upper layers of terminal device 200 (step S13). The MAC layer of terminal device 200 performs a first processing, which is MAC layer processing, in response to the instructions or notifications regarding MAC processing (step S14). The first processing is, for example, the execution of the received Timing advance command if a MAC reset is performed and the value of Timing advance command included in CSC is not FFF. The Timing advance command is, for example, processing that assumes RACH-less LTM cell switch is being performed. Furthermore, if the first process is associated with an SCG (Secondary Cell Group), the MAC layer may notify or indicate to the upper layer that it will skip the random access procedure for switching cells (step S15).
[0088] Furthermore, the first process includes, for example, the processing of the measured timing advance command if a MAC reset is performed, the timing advance measurement is configured, and the terminal device 200 has succeeded in measuring the timing advance for the specified LTM target. The processing of the timing advance command is, for example, a process that considers that a RACH-less LTM cell switch is being performed. If the first process is associated with the SCG, the MAC layer may notify or indicate to the upper layer that it will skip the random access procedure for the cell switching (step S15).
[0089] Furthermore, the first process may include the process of assuming in the RACH-less LTM cell switch that the SSB associated with the TCI state indicated by the TCI state ID included in the CSC is the SSB used to select the configured uplink grant for the first uplink transmission to the candidate cell.
[0090] The MAC layer notifies or instructs lower layers regarding information about the TCI state information included in the CSC (step S16).
[0091] Here, we will explain the parameters for channel measurement.
[0092] In CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), CRI (CSI-RS Resource Indicator), SSBRI (SS / PBCH Resource Block Indicator), LI (Layer Indicator), RI (Rank Indicator), L1-RSRP, L1-SINR, Capability Index, and TDCP (Time Domain Channel Properties), the terminal device 200 sets one or more upper-layer parameters CSI-ReportConfig report settings (reporting) according to the upper layer. A list of one or more trigger states may be configured, provided by one or more upper-layer parameters LTM-CSI-ReportConfig report settings, one or more upper-layer parameters CSI-ReportConfig resource settings, one or more upper-layer parameters LTM-CSI-ReportConfig resource settings, upper-layer parameters CSI-AperiodicTriggerStateList, and / or some or all of CSI-SemiPersistentOnPUSCH-TriggerStateList.
[0093] Each trigger state included in the upper-layer parameter CSI-AperiodicTriggerStateList may include a list of upper-layer parameters CSI-ReportConfig or LTM-CSI-ReportConfig that indicate resource set IDs for channel measurements and / or resource set IDs for interference measurements. The IDs may be indices. Resource sets for interference measurements may only exist in the report configuration provided by the upper-layer parameter CSI-ReportConfig. If the associated CSI-ReportConfig consists of a list of sub-configurations, a trigger state may further include one or more upper-layer parameter csi-ReportSubConfigIDs.
[0094] Each trigger state included in the higher-level parameter CSI-SemiPersistentOnPUSCH-TriggerStateList may include one associated CSI-ReportConfig or LTM-CSI-ReportConfig. If the associated CSI-ReportConfig consists of a list of sub-configurations, a trigger state may further include one or more higher-level parameters csi-ReportSubConfigID.
[0095] Each report setting in the upper layer parameter LTM-CSI-ReportConfig is associated with the upper layer parameter LTM-CSI-ReportConfig for channel measurement and may include parameters for time-domain operation provided by the upper layer parameter ltm-ReportConfigType, the number of candidate cells provided by the upper layer parameter nrOfReportedCells, and / or the number of reference signals per candidate cell provided by nrOfReportedRS-PerCell. If the upper layer parameter spCellInclusion is set, each report setting in the upper layer parameter LTM-CSI-ReportConfig may include L1 (Layer 1) measurement results associated with the current SpCell.
[0096] The time-domain operation of the terminal device 200, as defined by the upper-layer parameter LTM-CSI-ReportConfig, is indicated by the upper-layer parameter ltm-ReportConfigType and may be set to any of the following values: upper-layer parameter periodic, upper-layer parameter semiPersistentOnPUCCH, upper-layer parameter semiPersistentOnPUSCH, or upper-layer parameter periodic. When the upper-layer parameter periodic is set, the terminal device 200 may periodically transmit a CSI report to the base station device 100 (serving cell). The CSI report may include measurement results. If the upper layer parameter semiPersistentOnPUCCH is set, the terminal device 200 may periodically transmit CSI reports to the base station device 100 (serving cell) using PUCCH from the time it receives an instruction from the base station device 100 to start transmitting CSI reports until it receives an instruction from the base station device 100 to stop transmitting CSI reports. In the CSI report for the upper-layer parameters periodic, semiPersistentOnPUCCH, and semiPersistentOnPUSCH, the set period and set slot offset may be applied to the Numerology of the UL BWP to which the CSI report is configured to be sent. In the CSI report for the upper-layer parameters periodic, semiPersistentOnPUCCH, and semiPersistentOnPUSCH, the report period and slot offset may be derived based on the Numerology of the UL BWP to which the CSI report is sent.
[0097] In a terminal device 200 in which the upper layer parameter LTM-CSI-ReportConfig is set, for L1-RSRP measurement, one or all of the aperiodic, semi-permanent, or periodic CSIs may be associated with one resource setting specified by the upper layer parameter ltm-ResourceForChannelMeasurement.
[0098] Figure 7 shows an example of a cell switching procedure. The first cell is, for example, a cell belonging to the base station equipment 100. The first cell may also be a serving cell. This procedure may also be applied when there are multiple candidate cells. The terminal device 200 receives first information from the first cell, which includes information about the second cell, a candidate cell (step S20). This first information is, for example, configuration information necessary for uplink transmission and / or downlink reception in the second cell. The first information may also be the upper layer parameter CSI-MeasConfig in the second cell and the upper layer parameter linked to the upper layer parameter CSI-MeasConfig. Based on the first information received in S20, the terminal device 200 may receive the SSB and / or CSI-RS transmitted from the second cell and perform channel measurement (step S21). The terminal device 200 may transmit the measurement results performed in step S21 to the first cell (step S22). The first cell may transmit a PDCCH Order to the terminal device 200 (step S23) and instruct the second cell to transmit a PRACH. Here, the configuration information necessary for the PRACH transmission may be set based on the first information. The terminal device 200 may transmit a PRACH to the second cell based on the first information (step S24). The RACH Occasion used for the PRACH transmission may be a RACH Occasion linked to an SSB index included in the PDCCH Order. In step S24, the transmission of a PRACH by the terminal device 200 may be referred to as a RACH-based LTM. In step S24, the terminal device 200 does not have to transmit a PRACH, and the failure to transmit the PRACH before receiving the CSC may be referred to as RACH-less LTM. In the case of RACH-based LTM, the second cell may receive the PRACH transmitted by the terminal device 200 in step S24, measure the timing advance information, and transmit information about the timing advance to the first cell. The timing advance command may be derived from the timing advance information.Furthermore, information regarding timing advance may include timing advance information and / or timing advance command. The first cell may activate a TCI state to the terminal device 200 (step S26). Step S26 is optional. The first cell may transmit a CSC to the terminal device 200 and instruct it to switch to the second cell (step S27). The terminal device 200 may transmit a PRACH to the second cell (step S28). If the terminal device 200 transmitted a PRACH in step S24, the terminal device 200 does not need to transmit a PRACH in step S28. Furthermore, if the value of timing advance command included in CSC is other than FFF, the terminal device 200 does not need to transmit PRACH in step S28. The terminal device 200 may start uplink transmission to the second cell (step S29). The second cell may also instruct the terminal device 200 to measure the beam using CSI-RS (step S30). The first cell may also be described as the base station device 100 that forms the first cell. The second cell may also be described as the base station device 100 that forms the second cell.
[0099] In the cell switching procedure shown in Figure 7, after step S30, a beam measurement using CSI-RS is instructed, and then the beam measurement using CSI-RS is performed. The terminal device 200 may transmit the acquired channel information (CSI: Channel State Information) from the beam measurement to the target cell. The base station device 100 can perform high-throughput communication by setting transmission parameters for the downlink based on the CSI. The transmission parameters may also be MCS. However, between the time the terminal device 200 receives the CSC, measures the beam, and pairs the optimal beam, a decrease in cell switching performance, such as a decrease in throughput, may occur.
[0100] Therefore, the terminal device 200 can reduce the probability of performance degradation due to cell switching by performing CSI acquisition before or after receiving the CSC. Whether the CSI is acquired before or after receiving the CSC may depend on the capability of the terminal device 200. For example, the terminal device 200 may have a first capability that allows it to acquire (or measure) the CSI before receiving the CSC, or a second capability that does not allow it to acquire (or measure) the CSI before receiving the CSC. In other words, the terminal device 200 with the first capability can perform control regarding CSI acquisition before receiving the CSC, while the terminal device 200 with the second capability cannot perform control regarding CSI acquisition before receiving the CSC.
[0101] In the following explanation, the terminal device 200 having the first capability will be referred to as terminal device 200A, and the terminal device 200 having the second capability will be referred to as terminal device 200B. Furthermore, when terminal device 200A and terminal device 200B are not distinguished, they will be referred to simply as terminal device 200.
[0102] Here, we will explain a method by which the terminal device 200 performs CSI acquisition before and after receiving the CSC.
[0103] Figure 8 shows an example of a CSI acquisition method in the first example. Parts similar to those described in Figure 7 are denoted by the same reference numerals and their explanations are omitted. The CSI acquisition method may also be described as the CSI acquisition process. The first cell may also be described as the base station equipment 100 forming the first cell. The second cell may also be described as the base station equipment 100 forming the second cell. The first cell makes a cell switching decision based, for example, on the measurement results of L1-RSRP and / or L1-SINR transmitted from the terminal device 200. If the first cell decides to switch the terminal device 200 to the second cell, the first cell may, in step S31, transmit a CSI acquisition instruction to the terminal device 200. The CSI acquisition instruction may include CSI-RS configuration information transmitted by the second cell. The terminal device 200, upon receiving a CSI acquisition instruction, may perform CSI acquisition at the Target cell. The Target cell is, for example, the cell after cell switching, and is, for example, the second cell. The CSI acquisition instruction may also be described as a trigger that causes the terminal device 200 to start CSI acquisition. The first cell may be instructed to measure one or more CSI-RS from one or more CSI-RS configuration information contained in the first information of the second cell held by the terminal device 200. The CSI-RS configuration information may be a higher layer parameter CSI-MeasConfig and a higher layer parameter linked to the higher layer parameter CSI-MeasConfig. Furthermore, the CSI-RS configuration information may be part or all of the CSI resource set configuration, CSI resource configuration, and / or CSI report configuration. For example, in step S20, a signal containing one or more CSI-RS configuration information is transmitted, and when instructing the measurement information in step S31, the configuration information of the CSI-RS to be used for measurement is specified from among the one or more CSI-RS configuration information. For example, the CSI-RS configuration information is indicated using an index number corresponding to the CSI-RS configuration information.Step S31 may be performed at any time before the reception of the CSC (before step S27). For example, step S31 may be performed immediately after step S22. Alternatively, for example, step S31 may be performed immediately after step S26. The CSI acquisition instruction may be transmitted before the reception of the CSC. Note that the configuration information of one or more CSI-RSs may be included in the first information, for example.
[0104] In step S31, the terminal device 200A, upon receiving a CSI acquisition instruction, may perform CSI acquisition. The CSI-RS used by the terminal device 200A for CSI acquisition may be pre-set by higher-level parameters. One or more CSI-RSs may be pre-set by higher-level parameters and selected by the parameters included in the CSI acquisition instruction. Alternatively, the CSI-RS used by the terminal device 200A for CSI acquisition may be the CSI-RS associated with the Beam with the highest L1-RSRP and / or L1-SINR among the measurement results reported in step S22. The CSI-RS used for CSI acquisition may be a CSI-RS Resource Set or a CSI-RS Resource. A CSI-RS Resource Set may contain one or more CSI-RS Resources.
[0105] The cells in which terminal device 200A performs CSI acquisition may be determined based on parameters included in the CSI acquisition instruction. These parameters may be cell indexes. These parameters may be cells linked to some or all of the SSBRI and / or CRI.
[0106] The cell in which terminal device 200A performs CSI acquisition may be the cell indicated by the PDCCH Order in step S23. The cell in which terminal device 200A performs CSI acquisition may be the cell that receives the PDCCH Order in step S23 and is the target of PRACH transmission in step S24. If the cell in which terminal device 200A performs CSI acquisition is the cell indicated by the PDCCH Order in step S23, for example, step S31, which issues a CSI acquisition instruction, may be performed before step S23, which receives the PDCCH Order. If terminal device 200A receives a CSI acquisition instruction in step S31 and fails to receive the PDCCH Order within a predetermined time, terminal device 200A does not need to perform CSI acquisition. If terminal device 200A receives a CSI acquisition instruction in step S31 and fails to receive a PDCCH Order within a predetermined time, terminal device 200A may perform CSI acquisition on the cell with the highest RSRP among the measurement results reported in S22. If the cell on which terminal device 200A performs CSI acquisition is the cell indicated by the PDCCH Order in step S23, for example, step S31, which issues the CSI acquisition instruction, may be performed after step S23, which receives the PDCCH Order. If step S31 is performed after step S23, which receives the PDCCH Order, and terminal device 200A receives the CSI acquisition instruction in step S31 before receiving the PDCCH Order, terminal device 200A does not need to perform CSI acquisition. If step S31 is performed after step S23, which receives the PDCCH Order, and if the terminal device 200A receives the CSI acquisition instruction in step S31 before receiving the PDCCH Order, the terminal device 200A may perform CSI acquisition at the cell with the highest RSRP among the measurement results reported in S22.
[0107] The cell in which terminal device 200A performs CSI acquisition may be a cell included in the TCI state activation / deactivation MAC CE in step S26. If the cell in which terminal device 200A performs CSI acquisition is a cell included in the TCI state activation / deactivation MAC CE in step S26, step S31, which issues the CSI acquisition instruction, may be performed before step S26. If terminal device 200A receives the CSI acquisition instruction in step S31 and fails to receive the TCI state activation / deactivation MAC CE within a predetermined time, terminal device 200A does not need to perform CSI acquisition. If terminal device 200A receives a CSI acquisition instruction in step S31 and fails to receive a TCI state activation / deactivation MAC CE within a predetermined time, terminal device 200A may perform CSI acquisition on the cell with the highest RSRP among the measurement results reported in S22. If the cell on which terminal device 200A performs CSI acquisition is included in the TCI state activation / deactivation MAC CE of step S23, for example, step S31, which issues the CSI acquisition instruction, may be performed after step S23, which receives the TCI state activation / deactivation MAC CE. If step S31 is performed after step S26, which receives the TCI state activation / deactivation MAC CE, and the terminal device 200A receives the CSI acquisition instruction in step S31 before receiving the TCI state activation / deactivation MAC CE, the terminal device 200A does not need to perform CSI acquisition.If step S31 is performed after step S26, which receives the TCI state activation / deactivation MAC CE, and if terminal device 200A receives the CSI acquisition instruction in step S31 before receiving the TCI state activation / deactivation MAC CE, terminal device 200A may perform CSI acquisition at the cell with the highest RSRP among the measurement results reported in S22.
[0108] The CSI acquisition instruction may include information regarding the CSI-RS period for CSI acquisition. For example, the CSI acquisition instruction specifies part or all of the Periodic and / or Semi-persistent and / or Aperiodic, which are the CSI-RS transmission periods. Alternatively, the CSI-RS transmission period may be the period set in the CSI-RS Resource Set selected by the CSI acquisition instruction. The CSI acquisition instruction may also indicate an index of the upper-layer parameter CSI-ResourceConfig. The upper-layer parameter CSI-ResourceConfig may include one or more CSI-RS Resource Sets. Furthermore, the upper-layer parameter CSI-ResourceConfig may include a parameter that determines the transmission period of the CSI-RS Resource Set. For example, if a CSI acquisition instruction notifies the terminal device 200 of the index of CSI-ResourceConfig and the index of the CSI-RS Resource Set, the terminal device 200 may expect that the CSI-RS indicated by the CSI acquisition instruction will be transmitted at the transmission period set in CSI-ResourceConfig indicated by the CSI acquisition instruction.
[0109] If the transmission period of CSI-RS is semi-persistent, a CSI acquisition instruction may trigger a semi-persistent CSI-RS transmission. For example, if the transmission period of CSI-RS is semi-persistent, a semi-persistent CSI-RS may be transmitted a predetermined time after receiving a CSI acquisition instruction. If the transmission period of CSI-RS is semi-persistent, the RNTI scrambled to the PDCCH that schedules the CSI acquisition instruction may be a dedicated RNTI. This dedicated RNTI may be an RNTI for semi-persistent CSI-RS transmission for CSI acquisition that does not overlap with other RNTIs. The cessation of semi-persistent CSI-RS transmission may be performed when the base station device 100 receives a report of the CSI acquisition result from the terminal device 200.
[0110] If the CSI-RS transmission cycle is aperiodic, a CSI acquisition instruction may trigger an aperiodic CSI-RS transmission. For example, if the CSI-RS transmission cycle is aperiodic, an aperiodic CSI-RS is transmitted a predetermined time after receiving a CSI acquisition instruction. If the CSI-RS transmission cycle is aperiodic, the RNTI scrambled to the PDCCH that schedules the CSI acquisition instruction may be a dedicated RNTI. This dedicated RNTI may be an RNTI for aperiodic CSI-RS transmission for CSI acquisition that does not overlap with other RNTIs. The RNTI for aperiodic CSI-RS transmission may have the same value as the RNTI for semi-persistent CSI-RS transmission.
[0111] Furthermore, if terminal device 200B receives a CSI acquisition instruction, terminal device 200B may perform CSI acquisition after receiving CSC. If terminal device 200B does not receive a CSI acquisition instruction, terminal device 200B does not need to perform CSI acquisition after receiving CSC.
[0112] When terminal device 200B performs CSI acquisition, the measurement may be performed using the earliest CSI-RS transmitted a predetermined time after receiving the CSC. This predetermined time may take into account the processing time of the CSC by terminal device 200B. When terminal device 200B performs CSI acquisition, the measurement may be performed using the latest CSI-RS transmitted a predetermined time before the timing of reporting the CSI measurement results. This predetermined time may take into account the processing time of the CSI-RS measurement by terminal device 200B. When terminal device 200B performs CSI acquisition, the CSI may be acquired based on the received CSI acquisition instruction.
[0113] As described above, in Embodiment 1, the base station device 100 forming the first cell transmits a first signal containing configuration information for measuring a second signal transmitted from a second cell different from the first cell. Furthermore, when the base station device 100 forming the first cell transmits a fourth signal to the terminal device 200 to instruct it to switch from the first cell to the second cell, it controls the terminal device to transmit a third signal containing instruction information instructing it to transmit measurement information via the second cell after receiving the fourth signal. If the terminal device 200 has received the third signal containing instruction information to transmit measurement information, it transmits the measurement information via the second cell after receiving the fourth signal. In this way, measurement information can be transmitted after Cell Switch in LTM. Therefore, the base station device 100 forming the second cell can receive the CSI after Cell Switch by LTM. Furthermore, since the base station equipment 100 forming the second cell can recognize the CSI, it becomes possible to configure, for example, MCS (Modular Code Scheme) or MIMO (Multi-input Multi-output). This reduces the possibility of throughput degradation after Cell Switch by LTM. Embodiment 2
[0114] In Embodiment 1, an example was described in which a base station device 100 forming a first cell transmits a third signal containing instruction information to a terminal device 200 instructing it to transmit measurement information via a second cell after receiving a fourth signal, and then transmits a CSI to the terminal device 200 after a Cell Switch. Embodiment 2 describes an example in which multiple CSI acquisition instructions are received. In Embodiment 2, the terminal device, base station device, and communication system (wireless communication system) are the same as in Embodiment 1, so their description is omitted.
[0115] Figure 9 shows an example of a CSI acquisition method in Embodiment 2. Parts similar to those described in Figures 7 and 8 are denoted by the same reference numerals and their descriptions are omitted. Terminal device 200 may receive multiple CSI acquisition instructions. For example, after receiving a CSI acquisition instruction in step S31, terminal device 200 may receive another CSI acquisition instruction in step S32. If terminal device 200A receives multiple CSI acquisition instructions, terminal device 200A may complete the already triggered CSI acquisition measurements and start newly triggered CSI acquisition measurements. Terminal device 200A may save each measurement result and, when switching cells, report the CSI acquisition measurement results for the cell specified by the CSC to the second cell. If terminal device 200B receives multiple CSI acquisition instructions, terminal device 200B may perform CSI acquisition after receiving the CSC based on the last received CSI acquisition instruction.
[0116] Furthermore, if the terminal device 200 receives multiple CSI acquisition instructions, it may cancel or discard any CSI measurements already performed or in progress for CSI acquisition, and then perform a CSI measurement for CSI acquisition according to the last received CSI acquisition instruction. For example, if the terminal device 200A receives a CSI acquisition instruction in step S31 and is performing a CSI measurement, and then receives a new CSI acquisition instruction in step S32, it will cancel the CSI measurement corresponding to the CSI acquisition instruction received in step S31 and perform a CSI measurement corresponding to the CSI acquisition instruction received in step S32.
[0117] Furthermore, the terminal device 200B does not perform the CSI measurement instructed to acquire CSI in step S31, but instead performs the CSI measurement in accordance with the CSI acquisition instruction received in step S32.
[0118] As described above, in Embodiment 2, even when multiple CSI acquisition instructions are transmitted from the base station device 100 to the terminal device 200, the terminal device 200 can acquire CSI according to the situation. Therefore, the base station device 100 forming the second cell can receive the CSI after Cell Switching by LTM. Furthermore, since the base station device 100 forming the second cell can recognize the CSI, it becomes possible to configure, for example, MCS (Modular Code Scheme) or MIMO (Multi-input Multi-output). Therefore, the possibility of throughput degradation after Cell Switching by LTM can be reduced.
[0119] Embodiment 1 describes an example in which a base station device 100 forming a first cell transmits a third signal containing instruction information to a terminal device 200 instructing it to transmit measurement information via a second cell after receiving a fourth signal, and then transmits a CSI to the terminal device 200 after a Cell Switch. Embodiment 2 describes an example in which multiple CSI acquisition instructions are received. Embodiment 3 describes an example in which the cell in which the terminal device 200 performed CSI acquisition is different from the cell instructed by the CSC. In Embodiment 3, the terminal device, base station device, and communication system (wireless communication system) are the same as in Embodiments 1 and 2, so their description is omitted.
[0120] For example, in Figure 8, if the cell from which the CSI is to be acquired, as indicated by the CSI acquisition instruction transmitted in step S31, is different from the cell indicated in step S27, the terminal device 200 does not need to report the CSI acquisition result. For example, if the target cell included in the received CSC is different from the cell from which the CSI measurement for CSI acquisition was performed, the terminal device 200 does not need to transmit the measurement result of the CSI measurement to the base station device 100. Also, if the target cell included in the CSC received by the terminal device 200A is different from the cell from which the CSI measurement for CSI acquisition was performed, the terminal device 200A may receive the CSC and then perform CSI acquisition at the target cell included in the CSC. For example, if one or more cells whose CSI was measured in step S31 in Figure 8, or in step S31 and / or step S32 in Figure 9, are not instructed by the CSC in step S27, the terminal device 200A may perform CSI measurement for CSI acquisition at the cell to which the cell switching destination is instructed by the CSC.
[0121] The terminal device 200 may periodically report the CSI measurement results to the base station device 100. For example, CSI measurement and / or reporting may be performed after cell switching is completed. Alternatively, the terminal device 200 may report the CSI measurement results to the base station device 100 semi-periodically. The reporting may be stopped at the instruction of the base station device 100. The reporting may also be stopped when the terminal device 200 completes cell switching. The reporting may also be stopped when the terminal device 200 performs the first uplink transmission to the cell to which it switched. This first uplink transmission may include the RRC Establishment completion message.
[0122] As described above, in Embodiment 3, if the cell in which the CSI measurement for CSI acquisition was performed is different from the switching target cell included in the CSC, the transmission of the measurement results of the CSI measurement can be restricted. Furthermore, if any of the cells corresponding to one or more acquired CSIs are the same as the cell indicated by the CSC, the base station device 100 forming the second cell can recognize the CSI by using the method described in Embodiments 1 and 2. Therefore, for example, it becomes possible to configure MCS (Modularino Code Scheme) or MIMO (Multi-input Multi-output). Consequently, the possibility of throughput degradation after Cell Switch by LTM can be reduced.
[0123] [Hardware Configuration of Each Device in Each Embodiment] Based on Figures 10 and 11, the hardware configuration of each device in the wireless communication system of each embodiment will be described.
[0124] Figure 10 shows an example of the hardware configuration of the base station device 100 in this embodiment. As shown in Figure 11, the base station device 100 has, as hardware components, an RF (Radio Frequency) circuit 320 equipped with an antenna 310, a CPU (Central Processing Unit) 330, a DSP (Digital Signal Processor) 340, a memory 350, and a network IF (Interface) 360. The CPU is connected via a bus to enable input and output of various signals and data signals. The memory 350 includes, for example, at least one of RAM (Random Access Memory) such as SDRAM (Synchronous Dynamic Random Access Memory), ROM (Read Only Memory), and flash memory, and stores programs, control information, and data signals.
[0125] The correspondence between the functional configuration of the base station device 100 shown in Figure 2 and the hardware configuration of the base station device 100 shown in Figure 10 will be explained. The transmitting unit 111 and the receiving unit 112 (or communication unit 140) are realized by, for example, an RF circuit 320, or an antenna 310 and an RF circuit 320. The control unit 120 is realized by, for example, a CPU 330, a DSP 340, a memory 350, and a digital electronic circuit (not shown). Examples of digital electronic circuits include ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), and LSI (Large Scale Integration).
[0126] Furthermore, the base station device 100 can generate multiple data signals to be transmitted in multiple subbands, but the filters that generate these signals may be configured independently for each subband.
[0127] Figure 11 shows an example of the hardware configuration of the terminal device 200 in this embodiment. As shown in Figure 11, the terminal device 200 has, as hardware components, an RF circuit 420 equipped with an antenna 410, a CPU 430, and a memory 440. Furthermore, the terminal device 200 may have a display device such as an LCD (Liquid Crystal Display) connected to the CPU 430. The memory 440 includes, for example, RAM such as SDRAM, ROM, and flash memory, and stores programs, control information, and data signals.
[0128] The correspondence between the functional configuration of the terminal device 200 shown in Figure 3 and the hardware configuration of the terminal device 200 shown in Figure 11 will be explained. The transmitting unit 211 and the receiving unit 212 (or communication unit 210) are realized by, for example, an RF circuit 420, or an antenna 410 and an RF circuit 420. The control unit 220 is realized by, for example, a CPU 430, a DSP 440, a memory 450, and a digital electronic circuit (not shown). Examples of digital electronic circuits include ASICs, FPGAs, LSIs, etc.
[0129] In each embodiment, cell switching, Cell Switch, and LTM Cell Switch may have the same meaning. Performing CSI acquisition may be equivalent to performing measurements for CSI acquisition. CSI measurement may be equivalent to CSI acquisition. Reporting may be equivalent to transmitting.
[0130] Although each embodiment describes an example of a base station device, terminal, and repeater, the disclosed technology is not limited to these examples and can be applied to various devices such as electronic equipment mounted on automobiles, trains, airplanes, satellites, electronic equipment transported by drones, robots, AV equipment, home appliances, office equipment, vending machines, and other everyday devices.
[0131] Furthermore, although each embodiment was explained using fifth-generation mobile communication as an example, the disclosed technology is not limited to these. Each embodiment may also apply the disclosed technology to mobile communication of a different generation, such as sixth-generation or seventh-generation.
[0132] 1 Wireless Communication System 100A Base Station Equipment 100B Base Station Equipment C10 Cell C11 Cell 110 Wireless Communication Unit 111 Transmitter Unit 112 Receiver Unit 120 Control Unit 130 Memory Unit 140 Communication Unit 200 Terminal 210 Communication Unit 211 Transmitter Unit 212 Receiver Unit 220 Control Unit 310 Antenna 320 RF Circuit 330 CPU 340 DSP 350 Memory 360 Network IF 410 Antenna 420 RF Circuit 430 CPU 440 DSP 450 Memory
Claims
1. A terminal device comprising: a receiving unit that receives a first signal via a first cell containing configuration information for measuring a second signal transmitted from a second cell different from the first cell, and receives a fourth signal via the first cell instructing a switch from the first cell to the second cell; and a control unit that, when it has received a third signal containing instruction information instructing the transmission of measurement information, controls the device to transmit the measurement information via the second cell after receiving the fourth signal.
2. The terminal device according to claim 1, wherein the instruction information includes information instructing the measurement of the second signal, and the control unit controls the device to start measuring the second signal before receiving the fourth signal, in accordance with the instruction information.
3. The terminal device according to claim 1, wherein the instruction information includes information instructing the measurement of the second signal, and the control unit controls the device to start measuring the second signal after receiving the fourth signal, in accordance with the instruction information.
4. The terminal device according to claim 1, wherein the control unit controls the receiving unit to transmit, when it receives a plurality of instruction pieces of information, the first measurement piece obtained in accordance with the first instruction piece among the plurality of instruction pieces of information as the measurement piece of information.
5. The terminal device according to claim 4, wherein the first instruction information is the instruction information that was received last among the plurality of instruction information.
6. The terminal device according to claim 4, wherein the control unit cancels the CSI acquisition process in accordance with a second instruction information that is different from the first instruction information among the plurality of instruction information.
7. The terminal device according to claim 1, wherein when the receiving unit receives a plurality of instruction information, the control unit acquires a plurality of measurement information corresponding to the instruction information contained in each of the plurality of third signals, and the control unit controls the first measurement information from the plurality of measurement information that corresponds to the second cell instructed by the fourth signal to be transmitted as the measurement information.
8. The terminal device according to claim 1, wherein the control unit controls the transmission of the measurement information measured in accordance with the instruction information if the cell corresponding to the instruction information is different from the second cell.
9. A base station device comprising: a transmitting unit that transmits a first signal including configuration information for measuring a second signal transmitted from a second cell different from the first cell via a first cell in which a terminal device is located; and a control unit that, before transmitting a fourth signal to the terminal device to instruct it to switch from the first cell to the second cell, transmits a third signal including instruction information instructing the terminal device to transmit measurement information via the second cell after receiving the fourth signal.
10. A communication system comprising: a base station device that receives a first signal via a first cell containing configuration information for measuring a second signal transmitted from a second cell different from the first cell, and transmits a fourth signal via the first cell instructing a switch from the first cell to the second cell; and a terminal device that receives the first signal and the fourth signal, wherein the terminal device, upon receiving a third signal containing instruction information instructing the transmission of measurement information, is controlled to transmit the measurement information via the second cell after receiving the fourth signal.