JP2020137087A - Base station device, terminal device, and communication method - Google Patents

Abstract

To provide a base station device, a terminal device, and a communication method that can suppress an overhead involved in feedback from the terminal device when the base station device acquires highly accurate CSI and thereby improve frequency utilization efficiency or throughput.SOLUTION: A base station device according to one aspect of the present invention includes a transmission unit for transmitting at least one NZP CSI-RS and a reception unit for receiving a signal including at least one CSI. The CSI includes at least RI and PMI. The CSI further includes information indicating bases to be applied to a matrix having the PMI arranged in a predetermined dimension. The transmission unit signals a value indicating the number of the PMI arranged in the predetermined dimension and sets information in which the number of the PMI arranged in the predetermined dimension, a predetermined number, and the RI are associated with each other to the terminal device.SELECTED DRAWING: Figure 3

Description

The present invention relates to a base station device, a terminal device and a communication method.

Aiming to start commercial services around 2020, research and development activities related to the 5th generation mobile wireless communication system (5G system) are being actively carried out. Recently, the International Telecommunication Union Radiocommunication Sector (ITU-R), an international standardization organization, has issued a vision recommendation regarding the standard system (International mobile telecommunication --2020 and beyond: IMT-2020) for 5G systems. Reported (see Non-Patent Document 1).

Securing frequency resources is an important issue for communication systems to cope with the rapid increase in data traffic. Therefore, in 5G, one of the targets is to realize ultra-large capacity communication by using a frequency band higher than the frequency band (frequency band) used in LTE (Long term evolution).

It is important to utilize spatial resources to improve throughput. Even in 5G systems, multiple-inputs that use multiple antennas for transmission and reception
Utilization of Multiple-output: MIMO) technology is expected (see Non-Patent Document 2). Further, if the base station apparatus can grasp the channel state information (CSI) to and from the terminal apparatus, the efficiency of MIMO technology will be further enhanced.

As a method for the base station device to acquire the CSI, it is conceivable to feed back the CSI measured by the terminal device to the base station device. For example, the base station device and the terminal device share a codebook having a plurality of vectors indicating the state of the propagation path in advance, select the vector closest to the CSI measured by the terminal device from the codebook, and select the base station. By feeding back to the device, the base station device can grasp the state of the propagation path. In this case, the accuracy of the CSI that can be grasped by the base station apparatus depends on the accuracy of the codebook, and in simple terms, the accuracy of the CSI increases in proportion to the number of vectors described in the codebook.

Further, in order to realize high-speed transmission, widening the bandwidth of the transmission signal is indispensable, but widening the bandwidth of the transmission signal is nothing but shortening the time length (symbol length) of the transmission signal. Therefore, the intersymbol interference caused by the delayed wave cannot be ignored. This means that the transmitted signal propagates in a propagation path having frequency selectivity. Therefore, the CSI that the base station apparatus should grasp means that information considering frequency fluctuation is required in addition to spatial information.

“IMT Vision --Framework and overall objectives of the future development of IMT for 2020 and beyond,” Recommendation ITU-R M.2083-0, Sept. 2015. 3GPP RP-181453, “Enhancement on MIMO for NR,” June 2018.

As described above, the accuracy of the CSI that can be acquired by the base station device largely depends on the accuracy of the codebook referenced by the terminal device. Further, it is indispensable for the base station apparatus to acquire the CSI in consideration of the frequency selectivity of the propagation path in order to improve the efficiency of wideband transmission. However, this means that the overhead related to the feedback from the terminal device increases in order for the base station device to acquire the highly accurate CSI. In addition, the propagation environment changes from moment to moment due to the movement of the terminal device and changes in the surrounding environment, but when the delay related to feedback increases, the CSI acquired by the base station device becomes the propagation environment. There is a problem that cannot keep up with change.

The present invention has been made in view of such circumstances, and an object of the present invention is to suppress the overhead related to feedback from a terminal device when a base station device acquires a highly accurate CSI, thereby performing frequency utilization efficiency. Alternatively, it is an object of the present invention to provide a base station device, a terminal device, and a communication method capable of improving throughput.

The configuration of the base station device, the terminal device, and the communication method according to one aspect of the present invention for solving the above-mentioned problems is as follows.

(1) That is, the base station device according to one aspect of the present invention is a base station device that communicates with the terminal device, and includes a transmission unit that transmits at least one NZP CSI-RS and a signal including at least one CSI. The CSI includes at least RI and PMI, the CSI further contains information indicating a basis for applying the PMI to a matrix arranged in a predetermined dimension, and the transmitter includes said. A value indicating the number of the PMIs arranged in a predetermined dimension is signaled, and information in which the number of the PMIs arranged in the predetermined dimension, the number of bases, and the RI are associated with each other is set in the terminal device. ..

(2) Further, the base station apparatus according to one aspect of the present invention is described in (1) above, and the base station apparatus is set by the terminal apparatus when the terminal apparatus notifies RI larger than a predetermined value. Signal information indicating numbers.

(3) Further, the terminal device according to one aspect of the present invention is a terminal device that communicates with the base station device, and transmits a signal including at least one CSI and a receiving unit that receives at least one NZP CSI-RS. The CSI includes at least RI and PMI, the CSI further contains information indicating a basis for applying the PMI to a matrix arranged in a predetermined dimension, and the receiver includes the predetermined receiver. A value indicating the number of the PMIs arranged in the dimension is acquired, the value indicating the number of the PMIs arranged in the predetermined dimension exceeds the first predetermined value, and the RI value is the second predetermined value. If it exceeds, the number of vectors indicated by the PMI is set to a third predetermined value.

(4) Further, the communication method according to one aspect of the present invention is a communication method of a base station device that communicates with a terminal device, and includes a step of transmitting at least one NZP CSI-RS and at least one CSI. The CSI comprises at least RI and a PMI, comprising a step of receiving a signal, the CSI further comprising information indicating a basis for applying the PMI to a matrix arranged in a predetermined dimension, and further comprising the predetermined dimension. A step of signaling a value indicating the number of the PMIs arranged in the terminal device, a step of setting information associated with the number of the PMIs arranged in the predetermined dimension, the number of bases, and the RI in the terminal device. And.

According to the present invention, it is possible to suppress the overhead related to the feedback from the terminal device when the base station device acquires the highly accurate CSI, so that the frequency utilization efficiency or the throughput can be improved.

It is a figure which shows the example of the communication system which concerns on this embodiment. It is a block diagram which shows the structural example of the base station apparatus which concerns on this embodiment. It is a block diagram which shows the structural example of the terminal apparatus which concerns on this embodiment. It is a figure which shows the example of the communication system which concerns on this embodiment. It is a figure which shows the example of the communication system which concerns on this embodiment.

The communication system in the present embodiment includes a base station device (transmission device, cell, transmission point, transmission antenna group, transmission antenna port group, component carrier, eNodeB, transmission point, transmission / reception point, transmission panel, access point) and a terminal device (transmission device, cell, transmission point, transmission antenna group, transmission antenna port group). It includes a terminal, a mobile terminal, a receiving point, a receiving terminal, a receiving device, a receiving antenna group, a receiving antenna port group, a UE, a receiving point, a receiving panel, and a station). A base station device connected to a terminal device (establishing a wireless link) is called a serving cell.

The base station device and the terminal device in the present embodiment are also generally referred to as communication devices. At least a part of the communication methods implemented by the base station apparatus in the present embodiment can also be implemented by the terminal apparatus. Similarly, at least a part of the communication methods implemented by the terminal device in the present embodiment can also be implemented by the base station device.

The base station device and the terminal device in the present embodiment can communicate in a licensed frequency band (license band) and / or a license-free frequency band (unlicensed band).

In this embodiment, "X / Y" includes the meaning of "X or Y". In this embodiment, "X / Y" includes the meaning of "X and Y". In this embodiment, "X / Y" includes the meaning of "X and / or Y".

[1. First Embodiment]
FIG. 1 is a diagram showing an example of a communication system according to the present embodiment. As shown in FIG. 1, the communication system in this embodiment includes a base station device 1A and a terminal device 2A. Further, the coverage 1-1 is a range (communication area) in which the base station device 1A can be connected to the terminal device. Further, the base station device 1A is also simply referred to as a base station device. Further, the terminal device 2A is also simply referred to as a terminal device.

In FIG. 1, the following uplink physical channels are used in the uplink wireless communication from the terminal device 2A to the base station device 1A. The uplink physical channel is used to transmit the information output from the upper layer.
・ PUCCH (Physical Uplink Control Channel)
・ PUSCH (Physical Uplink Shared Channel)
・ PRACH (Physical Random Access Channel)

PUCCH is used to transmit Uplink Control Information (UCI). Here, the uplink control information is ACK (a positive acknowledgement) or NACK (a negative acknowledgement) (ACK / NACK) for downlink data (downlink transport block, Downlink-Shared Channel: DL-SCH).
)including. ACK / NACK for downlink data is also referred to as HARQ-ACK or HARQ feedback.

In addition, the uplink control information is the channel state information (Channel State) for the downlink.
Information: CSI) is included. In addition, the uplink control information includes a scheduling request (SR) used for requesting resources of the uplink-Shared Channel (UL-SCH). The channel state information includes a rank index RI (Rank Indicator) that specifies a suitable spatial multiplexing number, a precoding matrix index PMI (Precoding Matrix Indicator) that specifies a suitable precoder, and a channel quality index CQI that specifies a suitable transmission rate. (Channel Quality Indicator), CSI-RS (Reference Signal) resource indicator indicating suitable CSI-RS resource Measured by CRI (CSI-RS Resource Indicator), CSI-RS or SS (Synchronization Signal) RSRP (Reference Signal Received Power) is applicable.

The channel quality index CQI (hereinafter, CQI value) may be a suitable modulation method (for example, QPSK, 16QAM, 64QAM, 256QAM, etc.) in a predetermined band (details will be described later), and a coding rate. it can. The CQI value can be an index (CQI Index) determined by the change method or the coding rate. The CQI value can be set in advance by the system.

The CRI indicates a CSI-RS resource having a suitable reception power / reception quality from a plurality of CSI-RS resources.

The rank index and the recording quality index may be determined in advance by the system. The rank index and the pre-recording matrix index can be an index determined by spatial multiples and pre-recording matrix information. The CQI value, PMI value, RI value, and a part or all of the CRI value are also collectively referred to as a CSI value.

The PUSCH is used to transmit uplink data (uplink transport block, UL-SCH). The PUSCH may also be used to transmit ACK / NACK and / or channel state information along with uplink data. Further, PUSCH may be used to transmit only uplink control information.

PUSCH is also used to transmit RRC messages. RRC messages are information / information processed in the Radio Resource Control (RRC) layer.
It is a signal. In addition, PUSCH is used to transmit MAC CE (Control Element). Here, the MAC CE is information / signal processed (transmitted) in the medium access control (MAC) layer.

For example, power headroom may be included in the MAC CE and reported via PUSCH. That is, the MAC CE field may be used to indicate the level of power headroom.

PRACH is used to transmit a random access preamble.

Further, in uplink wireless communication, an uplink reference signal (UL RS) is used as an uplink physical signal. The uplink physical signal is not used to transmit the information output from the upper layer, but is used by the physical layer. Here, the uplink reference signal includes DMRS (Demodulation Reference Signal), SRS (Sounding Reference Signal), and PT-RS (Phase-Tracking reference signal).

DMRS is associated with the transmission of PUSCH or PUCCH. For example, the base station apparatus 1A uses DMRS to perform the propagation path correction of PUSCH or PUCCH. For example, base station apparatus 1A uses SRS to measure uplink channel status.
SRS is also used for uplink observation (sounding). PT-RS is also used to compensate for phase noise. The uplink DMRS is also referred to as an uplink DMRS.

In FIG. 1, the following downlink physical channels are used in the downlink wireless communication from the base station device 1A to the terminal device 2A. The downlink physical channel is used to transmit the information output from the upper layer.
・ PBCH (Physical Broadcast Channel)
・ PCFICH (Physical Control Format Indicator Channel)
・ PHICH (Physical Hybrid automatic repeat request Indicator Channel; HARQ indicator channel)
・ PDCCH (Physical Downlink Control Channel)
・ EPDCCH (Enhanced Physical Downlink Control Channel)
・ PDSCH (Physical Downlink Shared Channel)

PBCH is used to notify a master information block (MIB, Broadcast Channel: BCH) commonly used in terminal devices.
PCFICH is used to transmit information indicating a region used for PDCCH transmission (for example, the number of OFDM (Orthogonal Frequency Division Multiplexing) symbols). The MIB is also called the minimum system information.

PHICH is used to transmit ACK / NACK for uplink data (transport block, codeword) received by the base station apparatus 1A. That is, PHICH is used to transmit a HARQ indicator (HARQ feedback) indicating ACK / NACK for uplink data. ACK / NACK is also referred to as HARQ-ACK. The terminal device 2A notifies the upper layer of the received ACK / NACK. ACK / NACK is ACK indicating that the data was correctly received, NACK indicating that the data was not received correctly, and DTX indicating that there was no corresponding data. Further, when PHICH for the uplink data does not exist, the terminal device 2A notifies the upper layer of ACK.

PDCCH and EPDCCH are used to transmit Downlink Control Information (DCI). Here, a plurality of DCI formats are defined for the transmission of downlink control information. That is, the fields for downlink control information are defined in DCI format and mapped to information bits.

For example, as the DCI format for the downlink, the DCI format 1A used for scheduling one PDSCH (transmission of one downlink transport block) in one cell is defined.

For example, the DCI format for the downlink includes information regarding the resource allocation of the PDSCH, information regarding the MCS (Modulation and Coding Scheme) for the PDSCH, and downlink control information such as a TPC command for the PUCCH. Here, the DCI format for the downlink is also referred to as a downlink grant (or downlink assignment).

Also, for example, as a DCI format for uplink, 1 in one cell
DCI format 0 used for scheduling one PUSCH (transmission of one uplink transport block) is defined.

For example, the DCI format for the uplink includes uplink control information such as information on the resource allocation of the PUSCH, information on the MCS for the PUSCH, and TPC commands for the PUSCH. The DCI format for the uplink is also referred to as an uplink grant (or uplink assignment).

Further, the DCI format for the uplink can be used to request (CSI request) the channel state information (CSI; Channel State Information; also referred to as reception quality information) of the downlink.

The DCI format for the uplink can also be used to indicate the uplink resource that maps the channel state information report (CSI feedback report) that the terminal device feeds back to the base station device. For example, channel state information reporting can be used to indicate an uplink resource that periodically reports channel state information (Periodic CSI). The channel status information report can be used for setting a mode (CSI report mode) in which channel status information is reported periodically.

For example, channel state information reporting can be used to indicate an uplink resource that reports irregular channel state information (Aperiodic CSI). The channel status information report can be used for setting a mode (CSI report mode) in which channel status information is reported irregularly.

For example, channel state information reporting can be used to set up an uplink resource that reports semi-persistent CSI. The channel state information report can be used for the mode setting (CSI report mode) in which the channel state information is reported semipermanently. The semi-permanent CSI report is a periodic CSI report during the period of activation and deactivation with the signal of the upper layer or the downlink control information.

Further, the DCI format for the uplink can be used for setting indicating the type of channel state information report that the terminal device feeds back to the base station device. Types of channel state information reporting include wideband CSI (eg Wideband CQI) and narrowband CSI (eg Subband CQI).

When the PDSCH resource is scheduled using the downlink assignment, the terminal device receives the downlink data on the scheduled PDSCH. In addition, when the PUSCH resource is scheduled by using the uplink grant, the terminal device transmits uplink data and / or uplink control information by the scheduled PUSCH.

The PDSCH is used to transmit downlink data (downlink transport block, DL-SCH). The PDSCH is also used to transmit system information block type 1 messages. The system information block type 1 message is cell-specific (cell-specific) information.

The PDSCH is also used to send system information messages. The system information message includes a system information block X other than the system information block type 1. System information messages are cell-specific (cell-specific) information.

The PDSCH is also used to transmit RRC messages. Here, the RRC message transmitted from the base station device may be common to a plurality of terminal devices in the cell. Further, the RRC message transmitted from the base station device 1A may be a message dedicated to a certain terminal device 2A (also referred to as dedicated signaling). That is, user device specific (user device specific) information is transmitted to a certain terminal device using a dedicated message. The PDSCH is also used to transmit the MAC CE.

Here, the RRC message and / or MAC CE is also referred to as a higher layer signaling.

The PDSCH can also be used to request downlink channel state information. The PDSCH can also be used to transmit an uplink resource that maps a channel state information report (CSI feedback report) that the terminal device feeds back to the base station device. For example, channel state information reports regularly include channel state information (Periodic).
It can be used to set up an uplink resource that reports CSI). Channel status information report is a mode setting that periodically reports channel status information (CSI report mode).
Can be used for.

There are two types of downlink channel state information reporting: wideband CSI (eg Wideband CSI) and narrowband CSI (eg Subband CSI). Broadband CSI calculates one channel state information for the system bandwidth of the cell. The narrowband CSI divides the system band into predetermined units and calculates one channel state information for the division.

Further, in downlink wireless communication, a synchronization signal (SS) and a downlink reference signal (DL RS) are used as downlink physical signals. The downlink physical signal is not used to transmit the information output from the upper layer, but is used by the physical layer. The synchronization signals include a primary synchronization signal (PSS) and a secondary synchronization signal (SSS).

The synchronization signal is used by the terminal device to synchronize the downlink frequency domain and time domain. Synchronous signals are also used to measure received power, reception quality, or signal-to-interference and noise power ratio (SINR). The received power measured by the synchronization signal is SS-RSRP (Synchronization Signal --Reference Signal Received Power), the reception quality measured by the synchronization signal is SS-RSRQ (Reference Signal Received Quality), and the SINR measured by the synchronization signal is SS-. Also called SINR. SS-RSRQ is the ratio of SS-RSRP and RSSI. RSSI (Received Signal Strength Indicator) is the total average received power in a certain observation period. Further, the synchronization signal / downlink reference signal is used by the terminal device to correct the propagation path of the downlink physical channel. For example, the sync signal / downlink reference signal is used by the terminal device to calculate downlink channel state information.

Here, the downlink reference signals include DMRS (Demodulation Reference Signal), NZP CSI-RS (Non-Zero Power Channel State Information --Reference Signal), and ZP CSI-RS (Zero Power Channel State Information --Reference). Signal), PT-RS, and TRS (Tracking Reference Signal) are included. The downlink DMRS is also referred to as a downlink DMRS. In the following embodiments, the term CSI-RS includes NZP CSI-RS and / or ZP CSI-RS.

The DMRS is transmitted in the subframes and bands used to transmit the PDSCH / PBCH / PDCCH / EPDCCH associated with the DMRS and is used to demodulate the PDSCH / PBCH / PDCCH / EPDCCH associated with the DMRS.

The resources of the NZP CSI-RS are set by the base station apparatus 1A. For example, the terminal device 2A uses NZP CSI-RS to measure signals (measurement of channels) or measurement of interference. Further, NZP CSI-RS is used for beam scanning for searching a suitable beam direction, beam recovery for recovering when the received power / reception quality in the beam direction deteriorates, and the like. The resources of ZP CSI-RS are set by the base station apparatus 1A. The base station apparatus 1A transmits the ZP CSI-RS with zero output. For example, the terminal device 2A measures the interference at the resource corresponding to the ZP CSI-RS. The resource for interference measurement corresponding to ZP CSI-RS is also called CSI-IM (Interference Measurement) resource.

The base station apparatus 1A transmits (sets) the NZP CSI-RS resource setting for the resource of the NZP CSI-RS. The NZP CSI-RS resource configuration includes one or more NZP CSI-RS resource mappings, a CSI-RS resource configuration ID for each NZP CSI-RS resource, and some or all of the number of antenna ports. The CSI-RS resource mapping is information (for example, a resource element) indicating an OFDM symbol and a subcarrier in the slot in which the CSI-RS resource is arranged. The CSI-RS resource configuration ID is used to identify the NZP CSI-RS resource.

The base station apparatus 1A transmits (sets) the CSI-IM resource setting. The CSI-IM resource configuration includes one or more CSI-IM resource mappings, a CSI-IM resource configuration ID for each CSI-IM resource. The CSI-IM resource mapping is information (for example, a resource element) indicating an OFDM symbol and a subcarrier in the slot in which the CSI-IM resource is arranged. The CSI-IM resource setting ID is used to identify the CSI-IM setting resource.

CSI-RS is also used to measure received power, received quality, or SINR. The received power measured by CSI-RS is also called CSI-RSRP, the reception quality measured by CSI-RS is called CSI-RSRQ, and the SINR measured by CSI-RS is also called CSI-SINR. CSI-RSRQ is the ratio of CSI-RSRP to RSSI.

CSI-RS is also transmitted periodically / irregularly / semi-permanently.

Regarding CSI, the terminal device is set in the upper layer. For example, there are a report setting which is a CSI report setting, a resource setting which is a resource setting for measuring CSI, and a measurement link setting which links a report setting and a resource setting for CSI measurement. In addition, one or more report settings, resource settings, and measurement link settings are set.

Report settings include report setting ID, report setting type, codebook setting, CSI report amount, CQI table, group-based beam reporting, number of CQIs per report, and some or all of the number of CQIs per report in the lower ranks. The report setting ID is used to identify the report setting. The report configuration type indicates a periodic / non-regular / semi-permanent CSI report. The CSI reporting amount indicates the amount (value, type) to be reported, eg, part or all of CRI, RI, PMI, CQI, or RSRP. C
The QI table indicates the CQI table when calculating CQI. Group-based beam reporting is set to ON / OFF (enabled / disabled). The number of CQIs per report indicates the maximum number of CSIs per CSI report. Shows the maximum number of CQIs per report when RI is 4 or less. The number of CQIs for each report in the low rank may be applied when the number of CQIs for each report is 2. Codebook settings include the codebook type and its codebook settings. The codebook type indicates a type 1 codebook or a type 2 codebook. In addition, the codebook setting includes the setting of the type 1 codebook or the type 2 codebook.

The resource settings include a resource setting ID, a synchronous signal block resource measurement list, a resource setting type, and some or all of one or more resource set settings. The resource setting ID is used to specify the resource setting. The synchronization signal block resource setting list is a list of resources for which measurement is performed using the synchronization signal. The resource setting type indicates whether CSI-RS is transmitted periodically, irregularly, or semi-permanently. In the case of setting to transmit CSI-RS semipermanently, CSI-RS is periodically transmitted during the period from activation by the signal of the upper layer or downlink control information to deactivation. ..

The resource set configuration includes a resource set configuration ID, resource repetition, and some or all of the information indicating one or more CSI-RS resources. The resource set setting ID is used to specify the resource set setting. Resource repetition indicates ON / OFF of resource repetition in the resource set. When resource repetition is ON, it means that the base station apparatus uses a fixed (same) transmission beam for each of the plurality of CSI-RS resources in the resource set. In other words, when resource repetition is ON, the terminal equipment assumes that the base station equipment uses a fixed (same) transmission beam for each of the plurality of CSI-RS resources in the resource set. When resource repetition is OFF, it means that the base station apparatus does not use a fixed (same) transmission beam for each of the plurality of CSI-RS resources in the resource set. In other words, when resource repetition is OFF, the terminal equipment assumes that the base station equipment does not use a fixed (same) transmit beam for each of the plurality of CSI-RS resources in the resource set. The information indicating the CSI-RS resource includes one or more CSI-RS resource setting IDs and one or more CSI-IM resource setting IDs.

The measurement link setting includes a part or all of the measurement link setting ID, the report setting ID, and the resource setting ID, and the report setting and the resource setting are linked. The measurement link setting ID is used to specify the measurement link setting.

MBSFN (Multimedia Broadcast multicast service Single Frequency Network)
The RS is transmitted over the entire band of the subframe used to transmit the PMCH. MBSFN
RS is used to demodulate the PMCH. The PMCH is transmitted at the antenna port used to transmit the MBSFN RS.

Here, the downlink physical channel and the downlink physical signal are generically also referred to as a downlink physical signal. In addition, the uplink physical channel and the uplink physical signal are generically also referred to as an uplink signal. In addition, the downlink physical channel and the uplink physical channel are collectively referred to as a physical channel. Further, the downlink physical signal and the uplink physical signal are generically also referred to as a physical signal.

BCH, UL-SCH and DL-SCH are transport channels. The channel used in the MAC layer is called a transport channel. In addition, the unit of the transport channel used in the MAC layer is the transport block (Transport Bloc).
It is also called k: TB) or MAC PDU (Protocol Data Unit). A transport block is a unit of data that the MAC layer delivers to the physical layer. In the physical layer, the transport block is mapped to a codeword, and coding processing is performed for each codeword.

Further, for a terminal device that supports carrier aggregation (CA), the base station device can integrate and communicate with a plurality of component carriers (CC) for wider bandwidth transmission. .. In carrier aggregation, one primary cell (PCell; Primary Cell) and one or more secondary cells (SCell; Secondary Cell) are set as a set of serving cells.

In dual connectivity (DC), a master cell group (MCG) and a secondary cell group (SCG) are set as serving cell groups. The MCG consists of a PCell and optionally one or more SCells. The SCG is composed of a primary SCell (PSCell) and optionally one or more SCells.

The base station device can communicate using a wireless frame. A wireless frame is composed of a plurality of subframes (subsections). When the frame length is expressed in time, for example, the radio frame length can be 10 milliseconds (ms) and the subframe length can be 1 ms. In this example, the radio frame is composed of 10 subframes.

The slot is composed of 14 OFDM symbols. Since the OFDM symbol length can change depending on the subcarrier interval, the slot length can also be changed at the subcarrier interval. Mini slots also consist of fewer OFDM symbols than slots. Slots / minislots can be scheduling units. In the terminal device, slot-based scheduling / mini-slot-based scheduling can be known from the position (arrangement) of the first downlink DMRS. In slot-based scheduling, the first downlink DMRS is placed on the third or fourth symbol of the slot. In minislot-based scheduling, the first downlink DMRS is placed on the first symbol of the scheduled data (resource, PDSCH).

A resource block is defined by 12 consecutive subcarriers. The resource element is defined by a frequency domain index (eg, subcarrier index) and a time domain index (eg, OFDM symbol index). Resource elements are classified as uplink resource elements, downlink elements, flexible resource elements, and reserved resource elements. In the reserved resource element, the terminal device does not transmit the uplink signal and does not receive the downlink signal.

It also supports multiple Subcarrier spacings (SCSs). For example, the SCS is 15/30/60/120/240/480 kHz.

Base station equipment / terminal equipment can communicate in a licensed band or an unlicensed band. The base station device / terminal device has a license band of PCell and can communicate with at least one SCell operating in the unlicensed band by carrier aggregation. Further, the base station device / terminal device can communicate in dual connectivity, in which the master cell group communicates in the license band and the secondary cell group communicates in the unlicensed band. Further, the base station device / terminal device can communicate only with the PCell in the unlicensed band. Further, the base station device / terminal device can communicate by CA or DC only in the unlicensed band. It should be noted that the license band becomes PCell, and the cells (SCell, PSCell) of the unlicensed band are assisted and communicated by, for example, CA or DC, which is also called LAA (Licensed-Assisted Access). Further, the communication between the base station device / terminal device only in the unlicensed band is also called unlicensed-standalone access (ULSA). Further, the communication between the base station device / terminal device only in the license band is also referred to as licensed access (LA).

FIG. 2 is a schematic block diagram showing the configuration of the base station apparatus according to the present embodiment. As shown in FIG. 2, the base station apparatus includes an upper layer processing unit (upper layer processing step) 101, a control unit (control step) 102, a transmission unit (transmission step) 103, a reception unit (reception step) 104, and a transmission / reception antenna. It includes 105 and a measuring unit (measurement step) 106. Further, the upper layer processing unit 101 includes a radio resource control unit (radio resource control step) 1011 and a scheduling unit (scheduling step) 1012. Further, the transmission unit 103 includes a coding unit (coding step) 1031, a modulation unit (modulation step) 1032, a downlink reference signal generation unit (downlink reference signal generation step) 1033, a multiplexing unit (multiplexing step) 1034, and a radio. It is configured to include a transmission unit (radio transmission step) 1035. Further, the receiving unit 104 includes a wireless receiving unit (radio receiving step) 1041, a multiple separation unit (multiple separation step) 1042, a demodulation unit (demodulation step) 1043, and a decoding unit (decoding step) 1044.

The upper layer processing unit 101 includes a medium access control (MAC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a radio resource control (Radio). Resource Control: RRC) Performs layer processing. Further, the upper layer processing unit 101 generates information necessary for controlling the transmission unit 103 and the reception unit 104, and outputs the information to the control unit 102.

The upper layer processing unit 101 receives information about the terminal device, such as the function of the terminal device (UE capability), from the terminal device. In other words, the terminal device transmits its function to the base station device as an upper layer signal.

In the following description, the information about the terminal device includes information indicating whether or not the terminal device supports a predetermined function, or information indicating that the terminal device has been introduced and tested for the predetermined function. In the following description, whether or not to support a predetermined function includes whether or not the introduction and testing of the predetermined function have been completed.

For example, when the terminal device supports a predetermined function, the terminal device transmits information (parameter) indicating whether or not the predetermined function is supported. If the terminal does not support a given function, the terminal does not send information (parameters) indicating whether it supports the given function. That is, whether or not to support the predetermined function is notified by whether or not to transmit information (parameter) indicating whether or not to support the predetermined function. Information (parameter) indicating whether or not to support a predetermined function may be notified by using 1 bit of 1 or 0.

The radio resource control unit 1011 generates downlink data (transport block), system information, RRC message, MAC CE, etc. arranged in the downlink PDSCH, or acquires them from an upper node. The radio resource control unit 1011 outputs downlink data to the transmission unit 103, and outputs other information to the control unit 102. In addition, the wireless resource control unit 1011 manages various setting information of the terminal device.

The scheduling unit 1012 determines the frequency and subframe to which the physical channels (PDSCH and PUSCH) are assigned, the coding rate of the physical channels (PDSCH and PUSCH), the modulation method (or MCS), the transmission power, and the like. The scheduling unit 1012 outputs the determined information to the control unit 102.

The scheduling unit 1012 generates information used for scheduling physical channels (PDSCH and PUSCH) based on the scheduling result. The scheduling unit 1012 outputs the generated information to the control unit 102.

The control unit 102 generates a control signal for controlling the transmission unit 103 and the reception unit 104 based on the information input from the upper layer processing unit 101. The control unit 102 generates downlink control information based on the information input from the upper layer processing unit 101, and outputs the downlink control information to the transmission unit 103.

The transmission unit 103 generates a downlink reference signal according to the control signal input from the control unit 102, and encodes the HARQ indicator, the downlink control information, and the downlink data input from the upper layer processing unit 101. And modulated, the PHICH, PDCCH, EPDCCH, PDSCH, and downlink reference signals are multiplexed and transmitted to the terminal device 2A via the transmit / receive antenna 105.

The coding unit 1031 uses block coding, convolutional coding, turbo coding, and LDPC (low density parity check: Low density) for the HARQ indicator, downlink control information, and downlink data input from the upper layer processing unit 101. parity check) Coding is performed using a predetermined coding method such as coding or Polar coding, or coding is performed using a coding method determined by the radio resource control unit 1011. The modulation unit 1032 uses predetermined coding bits input from the coding unit 1031 such as BPSK (Binary Phase Shift Keying), QPSK (quadrature Phase Shift Keying), 16QAM (quadrature amplitude modulation), 64QAM, and 256QAM. Alternatively, modulation is performed by the modulation method determined by the radio resource control unit 1011.

The downlink reference signal generation unit 1033 refers to a sequence known to the terminal device 2A, which is obtained by a predetermined rule based on a physical cell identifier (PCI, cell ID) for identifying the base station device 1A. Generate as a signal.

The multiplexing unit 1034 multiplexes the modulated symbol of each modulated channel, the generated downlink reference signal, and the downlink control information. That is, the multiplexing unit 1034 arranges the modulated symbol of each modulated channel, the generated downlink reference signal, and the downlink control information in the resource element.

The radio transmitter 1035 generates an OFDM symbol by performing an inverse fast Fourier transform (IFFT) on a multiplexed modulation symbol or the like, and adds a cyclic prefix (CP) to the OFDM symbol as a base. Generates a band digital signal, converts the baseband digital signal into an analog signal, removes excess frequency components by filtering, upconverts to the carrier frequency, amplifies the power, outputs it to the transmit / receive antenna 105, and transmits it. .. The transmission power at this time is based on the information set via the control unit 102.

The receiving unit 104 separates, demodulates, and decodes the received signal received from the terminal device 2A via the transmission / reception antenna 105 according to the control signal input from the control unit 102, and outputs the decoded information to the upper layer processing unit 101. .. The receiving unit 104 also has a function (step) for performing carrier sense.

The radio receiver 1041 converts the uplink signal received via the transmission / reception antenna 105 into a baseband signal by down-conversion, removes unnecessary frequency components, and amplifies the signal level so as to be properly maintained. The level is controlled, and based on the in-phase component and the quadrature component of the received signal, quadrature demodulation is performed, and the quadrature demodulated analog signal is converted into a digital signal.

The radio receiving unit 1041 removes a portion corresponding to the CP from the converted digital signal. The radio reception unit 1041 performs a fast Fourier transform (FFT) on the signal from which the CP has been removed, extracts a signal in the frequency domain, and outputs the signal to the multiplex separation unit 1042.

The multiplex separation unit 1042 separates the signal input from the wireless reception unit 1041 into signals such as PUCCH, PUSCH, and uplink reference signals. Note that this separation is performed based on the radio resource allocation information included in the uplink grant that the base station device 1A determines in advance by the radio resource control unit 1011 and notifies each terminal device 2A.

Further, the multiplex separation unit 1042 compensates for the propagation paths of PUCCH and PUSCH. Further, the multiplex separation unit 1042 separates the uplink reference signal.

The demodulation unit 1043 performs Inverse Discrete Fourier Transform (IDFT) on PUSCH to acquire modulation symbols, and for each of the modulation symbols of PUCCH and PUSCH, BPSK, QPSK, 16QAM, 64QAM, 256QAM, etc. The received signal is demodulated by using the modulation method that is determined or that the own device notifies the terminal device 2A in advance by the uplink grant.

The decoding unit 1044 sets the demodulated PUCCH and PUSCH coding bits at a predetermined coding method, or at a coding rate that the own device notifies the terminal device 2A in advance by an uplink grant. Decryption is performed, and the decoded uplink data and uplink control information are output to the upper layer processing unit 101. When the PUSCH is retransmitted, the decoding unit 1044 performs decoding using the coding bits held in the HARQ buffer input from the upper layer processing unit 101 and the demodulated coding bits.

The measuring unit 106 observes the received signal and obtains various measured values such as RSRP / RSRQ / RSSI. Further, the measuring unit 106 obtains the received power, the reception quality, and the suitable SRS resource index from the SRS transmitted from the terminal device.

FIG. 3 is a schematic block diagram showing the configuration of the terminal device according to the present embodiment. As shown in FIG. 3, the terminal device includes an upper layer processing unit (upper layer processing step) 201, a control unit (control step) 202, a transmission unit (transmission step) 203, a reception unit (reception step) 204, and a measurement unit ( Measurement step) 205 and transmission / reception antenna 206 are included. Further, the upper layer processing unit 201 includes a radio resource control unit (radio resource control step) 2011 and a scheduling information interpretation unit (scheduling information interpretation step) 2012. Further, the transmission unit 203 includes a coding unit (coding step) 2031, a modulation unit (modulation step) 2032, an uplink reference signal generation unit (uplink reference signal generation step) 2033, a multiplexing unit (multiplexing step) 2034, and a radio. It is configured to include a transmission unit (radio transmission step) 2035. Further, the receiving unit 204 includes a wireless receiving unit (radio receiving step) 2041, a multiplex separation unit (multiplex separation step) 2042, and a signal detection unit (signal detection step) 2043.

The upper layer processing unit 201 outputs the uplink data (transport block) generated by the user's operation or the like to the transmission unit 203. In addition, the upper layer processing unit 201 includes a medium access control (MAC) layer and a packet data integration protocol (Packet).
Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC)
Layers and radio resource control (RRC) layer processing is performed.

The upper layer processing unit 201 outputs information indicating the function of the terminal device supported by the own terminal device to the transmission unit 203.

The wireless resource control unit 2011 manages various setting information of the own terminal device. Further, the radio resource control unit 2011 generates information arranged in each channel of the uplink and outputs the information to the transmission unit 203.

The radio resource control unit 2011 acquires the setting information transmitted from the base station device and outputs it to the control unit 202.

The scheduling information interpretation unit 2012 interprets the downlink control information received via the reception unit 204 and determines the scheduling information. Further, the scheduling information interpretation unit 2012 generates control information for controlling the receiving unit 204 and the transmitting unit 203 based on the scheduling information, and outputs the control information to the control unit 202.

The control unit 202 generates a control signal for controlling the receiving unit 204, the measuring unit 205, and the transmitting unit 203 based on the information input from the upper layer processing unit 201. The control unit 202 outputs the generated control signal to the reception unit 204, the measurement unit 205, and the transmission unit 203 to control the reception unit 204 and the transmission unit 203.

The control unit 202 controls the transmission unit 203 so as to transmit the CSI / RSRP / RSRQ / RSSI generated by the measurement unit 205 to the base station apparatus.

The receiving unit 204 separates, demodulates, and decodes the received signal received from the base station apparatus via the transmission / reception antenna 206 according to the control signal input from the control unit 202, and outputs the decoded information to the upper layer processing unit 201. To do. The receiving unit 204 also has a function (step) for executing carrier sense.

The radio receiver 2041 converts the downlink signal received via the transmission / reception antenna 206 into a baseband signal by down-conversion, removes unnecessary frequency components, and amplifies the signal level so that the signal level is properly maintained. Is quadrature demodulated based on the in-phase component and the quadrature component of the received signal, and the quadrature demodulated analog signal is converted into a digital signal.

Further, the radio reception unit 2041 removes a portion corresponding to the CP from the converted digital signal, performs a fast Fourier transform on the signal from which the CP has been removed, and extracts a signal in the frequency domain.

The multiplex separator 2042 separates the extracted signal into PHICH, PDCCH, EPDCCH, PDSCH, and downlink reference signals, respectively. Further, the multiplex separation unit 2042 compensates the channels of PHICH, PDCCH, and EPDCCH based on the estimated value of the channel of the desired signal obtained from the channel measurement, detects the downlink control information, and causes the control unit 202. Output. Further, the control unit 202 outputs the PDSCH and the channel estimation value of the desired signal to the signal detection unit 2043.

The signal detection unit 2043 detects a signal using the PDSCH and the channel estimation value, and outputs the signal to the upper layer processing unit 201.

The measuring unit 205 performs various measurements such as CSI measurement, RRM (Radio Resource Management) measurement, and RLM (Radio Link Monitoring) measurement, and obtains CSI / RSRP / RSRQ / RSSI and the like.

The transmission unit 203 generates an uplink reference signal according to the control signal input from the control unit 202, encodes and modulates the uplink data (transport block) input from the upper layer processing unit 201, and performs PUCCH, The PUSCH and the generated uplink reference signal are multiplexed and transmitted to the base station apparatus via the transmission / reception antenna 206.

The coding unit 2031 performs coding such as convolutional coding, block coding, turbo coding, LDPC coding, and Polar coding on the uplink control information or uplink data input from the upper layer processing unit 201.

The modulation unit 2032 modulates the coding bits input from the coding unit 2031 by a modulation method notified by downlink control information such as BPSK, QPSK, 16QAM, 64QAM, or a modulation method predetermined for each channel. ..

The uplink reference signal generator 2033 uses a physical cell identifier (referred to as PCI, Cell ID, etc.) for identifying the base station device, a bandwidth for arranging the uplink reference signal, and an uplink grant. A series obtained by a predetermined rule (expression) is generated based on the notified cyclic shift, the value of the parameter for the generation of the DMRS sequence, and the like.

The multiplexing unit 2034 multiplexes the PUCCH and PUSCH signals and the generated uplink reference signal for each transmitting antenna port. That is, the multiplexing unit 2034 arranges the PUCCH and PUSCH signals and the generated uplink reference signal in the resource element for each transmission antenna port.

The radio transmitter 2035 converts the multiplexed signal into an inverse fast Fourier transform.
Transform: IFFT) to perform OFDM modulation, generate an OFDMA symbol, add CP to the generated OFDMA symbol, generate a baseband digital signal, and convert the baseband digital signal to an analog signal. Then, the excess frequency component is removed, the frequency is converted to the carrier frequency by up-conversion, the power is amplified, and the signal is output to the transmission / reception antenna 206 for transmission.

The terminal device is not limited to the OFDMA system, and can perform modulation by the SC-FDMA system.

When ultra-large capacity communication such as ultra-high-definition video transmission is required, ultra-wideband transmission utilizing high frequency bands is desired. For transmission in the high frequency band, it is necessary to compensate for path loss, and beamforming is important. Further, in an environment where a plurality of terminal devices exist in a limited area, when ultra-large capacity communication is required for each terminal device, an ultra-dense network in which base station devices are arranged at high density (Ultra-dense) network) is valid. However, when the base station equipment is arranged at high density, SNR (Signal to noise ratio: Signal to noise)
Although the power ratio) is greatly improved, there is a possibility that strong interference due to beamforming will come. Therefore, in order to realize ultra-large capacity communication for all terminal devices in a limited area, interference control (avoidance, suppression, elimination) in consideration of beamforming and / or coordinated communication of a plurality of base stations is performed. You will need it.

FIG. 4 shows an example of a downlink communication system according to the present embodiment. The communication system shown in FIG. 4 includes a base station device 3A, a base station device 5A, and a terminal device 4A. The terminal device 4A can use the base station device 3A and / or the base station device 5A as a serving cell. When the base station device 3A or the base station device 5A is provided with a large number of antennas, the large number of antennas can be divided into a plurality of sub-arrays (panels, sub-panels), and transmission / reception beamforming can be applied to each sub-array. In this case, each sub-array may be provided with a communication device, and the configuration of the communication device is the same as the base station device configuration shown in FIG. 2 unless otherwise specified. Further, when the terminal device 4A includes a plurality of antennas, the terminal device 4A can transmit or receive by beamforming. Further, when the terminal device 4A is provided with a large number of antennas, the large number of antennas can be divided into a plurality of sub-arrays (panels, sub-panels), and different transmission / reception beamforming can be applied to each sub-array. Each sub-array can be provided with a communication device, and the configuration of the communication device is the same as the terminal device configuration shown in FIG. 3 unless otherwise specified. The base station device 3A and the base station device 5A are also simply referred to as base station devices. The terminal device 4A is also simply referred to as a terminal device.

Synchronous signals are used to determine a suitable transmit beam for a base station device and a suitable receive beam for a terminal device. The base station apparatus transmits a synchronization signal block (SS block, SSB) composed of PSS, PBCH, and SSS. Within the synchronization signal block burst set cycle set by the base station apparatus, one or more synchronization signal blocks are transmitted in the time domain, and a time index is set for each synchronization signal block. The terminal device has the same time index sync signal block within the sync signal block burst set cycle, delay spread, Doppler spread, Doppler shift, average gain, average delay, spatial receive parameters, and / or spatial transmit parameters. Can be considered to have been sent from the same location (quasi co-located: QCL) to some extent so that they can be considered the same. The spatial reception parameters are, for example, the spatial correlation of the channel, the angle of arrival, and the like. The spatial transmission parameters are, for example, the spatial correlation of the channel, the transmission angle (Angle of Departure), and the like. That is, the terminal can assume that within the synchronous signal block burst set cycle, synchronous signal blocks with the same time index are transmitted with the same transmission beam, and synchronous signal blocks with different time indexes are transmitted with different beams. Therefore, if the terminal device reports to the base station device information indicating a time index of a suitable synchronous signal block within the synchronous signal block burst set cycle, the base station device can know a transmission beam suitable for the terminal device. Further, the terminal device can obtain a reception beam suitable for the terminal device by using the synchronization signal blocks having the same time index in different synchronization signal block burst set cycles. Therefore, the terminal device can associate the time index of the synchronization signal block with the receive beam direction and / or subarray. When the terminal device includes a plurality of sub-arrays, different sub-arrays may be used when connecting to different cells.

In addition, CSI-RS can be used to determine the transmit beam of a suitable base station device and the receive beam of a suitable terminal device. The base station device can set the setting information by the signal of the upper layer. For example, configuration information includes some or all of resource settings, reporting settings.

Resource settings include a resource setting ID, a resource setting type, and / or one or more CSI-RS resource set settings. The resource setting ID is used to specify the resource setting. The resource setting type indicates the behavior of the resource setting in the time domain. Specifically, the resource setting is a setting to send CSI-RS aperiodically, a setting to send CSI-RS periodically (periodic), or a semi-persistent CS.
Indicates whether the setting is to transmit I-RS. The CSI-RS resource set configuration includes a CSI-RS resource set configuration ID and / or one or more CSI-RS resource settings. The CSI-RS resource set setting ID is used to identify the CSI-RS resource set setting. The CSI-RS resource configuration includes a CSI-RS resource configuration ID, a resource configuration type, the number of antenna ports, a CSI-RS resource mapping, and some or all of the CSI-RS and PDSCH power offsets. The CSI-RS resource setting ID is used to identify the CSI-RS resource setting, and the CSI-RS resource setting ID is associated with the CSI-RS resource. The CSI-RS resource mapping indicates a resource element (OFDM symbol, subcarrier) in which the CSI-RS in the slot is placed.

Resource settings are used for CSI or RRM measurements. The terminal device receives the CSI-RS with the set resource, calculates the CSI from the CSI-RS, and reports it to the base station device. Further, when the CSI-RS resource set setting includes a plurality of CSI-RS resource settings, the terminal device receives the CSI-RS with the same reception beam in each CSI-RS resource and calculates the CRI. For example, if the CSI-RS resource set setting includes K (K is an integer greater than or equal to 2) CSI-RS resource settings, the CRI indicates from K CSI-RS resources to N suitable CSI-RS resources. .. However, N is a positive integer less than K. Also, if the CRI indicates multiple CSI-RS resources, the terminal device should report the CSI-RSRP measured with each CSI-RS resource to the base station device to indicate which CSI-RS resource is of good quality. Can be done. If the base station device beamforms (precodes) CSI-RS in different beam directions with a plurality of set CSI-RS resources and transmits the CSI-RS, the base station device suitable for the terminal device is based on the CRI reported from the terminal device. You can know the transmission beam direction of. On the other hand, the reception beam direction of a suitable terminal device can be determined by using a CSI-RS resource in which the transmission beam of the base station device is fixed. For example, the base station apparatus transmits to a CSI-RS resource information indicating whether or not the transmission beam of the base station apparatus is fixed, and / or a period during which the transmission beam is fixed. The terminal device can obtain a suitable reception beam direction from the CSI-RS received in different reception beam directions in the CSI-RS resource in which the transmission beam is fixed. The terminal device may report CSI-RSRP after determining a suitable reception beam direction. When the terminal device includes a plurality of sub-arrays, the terminal device can select a suitable sub-array when determining a suitable reception beam direction. The preferred receiving beam direction of the terminal device may be associated with CRI. Also, if the terminal equipment reports multiple CRIs, the base station equipment can fix the transmit beam with the CSI-RS resource associated with each CRI. At this time, the terminal device can determine a suitable reception beam direction for each CRI. For example, the base station apparatus can transmit the downlink signal / channel in association with the CRI. At this time, the terminal device must receive with the receiving beam associated with the CRI. In addition, different base station devices can transmit CSI-RS in a plurality of set CSI-RS resources. In this case, the network side can know from which base station device the communication quality is good by CRI. Further, when the terminal device includes a plurality of sub-arrays, it is possible to receive in a plurality of sub-arrays at the same timing. Therefore, if the base station device transmits a CRI in association with each of a plurality of layers (codeword, transport block) by downlink control information or the like, the terminal device uses the sub-array and reception beam corresponding to each CRI. Can receive multiple layers. However, when using an analog beam, when one sub-array uses one receiving beam direction at the same timing and two CRIs corresponding to one sub-array of the terminal device are set at the same time, the terminal device is used. It may not be possible to receive with multiple receiving beams. In order to avoid this problem, for example, the base station apparatus groups a plurality of set CSI-RS resources, and within the group, the same sub-array is used to obtain CRI. Further, if different sub-arrays are used between the groups, the base station apparatus can know a plurality of CRIs that can be set at the same timing. The group of CSI-RS resources may be a CSI-RS resource set. The CRI that can be set at the same timing may be a QCL. At this time, the terminal device can transmit the CRI in association with the QCL information. For example, if the terminal device reports the CRI that is QCL and the CRI that is not QCL separately, the base station device does not set the CRI that is QCL at the same timing, and the CRI that is not QCL is set at the same timing. Can be done. Further, the base station device may request a CSI for each sub-array of the terminal device. In this case, the terminal device reports the CSI for each subarray. When the terminal device reports a plurality of CRIs to the base station device, it may report only the CRIs that are not QCLs.

The reporting settings are settings for CSI reporting and include the reporting setting ID, the reporting setting type, and / or the reported value (quantity). The report setting ID is used to identify the report setting. The reported value (quantity) is the CSI value (quantity) to be reported. The reporting setting type is a setting in which the reporting setting reports the CSI value (quantity) aperiodically, a setting in which the CSI value (quantity) is reported periodically, or a semi-persistent. ) Is set to report the CSI value (quantity).

When reporting a CSI aperiodically or semi-permanently, the base station device transmits a trigger (trigger information) to start reporting the CSI to the terminal device. The trigger can be DCI or higher layer signaling.

Further, in order to determine a suitable transmission beam of a base station apparatus, a codebook in which candidates for a predetermined precoding (beamforming) matrix (vector) are defined is used. The base station device transmits CSI-RS, and the terminal device obtains a suitable precoding (beamforming) matrix from the codebook and reports it to the base station device as PMI. As a result, the base station apparatus can know the transmission beam direction suitable for the terminal apparatus. The codebook has a precoding (beamforming) matrix for synthesizing antenna ports and a precoding (beamforming) matrix for selecting antenna ports. When using a codebook for selecting antenna ports, the base station apparatus can use different transmission beam directions for each antenna port. Therefore, if the terminal device reports a suitable antenna port as the PMI, the base station device can know the suitable transmission beam direction. The suitable reception beam of the terminal device may be the reception beam direction associated with the CRI, or the suitable reception beam direction may be determined again. When using a codebook that selects an antenna port, if the preferred receive beam direction of the terminal device is the receive beam direction associated with the CRI, then the receive beam direction that receives the CSI-RS is the receive beam associated with the CRI. It is desirable to receive in the direction. The terminal device can associate the PMI with the received beam direction even when the received beam direction associated with the CRI is used. Further, when a codebook for selecting an antenna port is used, each antenna port may be transmitted from a different base station device (cell). In this case, if the terminal device reports the PMI, the base station device can know which base station device (cell) is suitable for communication quality. In this case, it can be said that the antenna ports of different base station devices (cells) are not QCLs.

If the PUSCH reports a CSI, or if the PUCCH reports a subband CSI, the CSI is reported in two parts. In addition, CSI reports include Type 1 CSI reports and Type 2 CSI reports. In the Type 1 CSI report, a CSI based on the Type 1 Codebook (also referred to as a Type 1 CSI) is reported. In the Type 2 CSI report, a CSI based on the Type 2 Codebook (also referred to as a Type 2 CSI) is reported. The two parts are also referred to as a first part (part 1, CSI part 1) and a second part (part 2, CSI part 2). The first part has a higher priority for CSI reporting than the second part. For example, if the RI is 4 or less, the first part is the sum of the first RI and the second RI (or the second RI), the second CRI, the first CRI and the CQI based on the second CRI. Includes part or all of (or second CQI). The second part includes a part or all of the first CRI, the first RI, the first CQI, the first PMI, the second PMI. If the RI is greater than 4, the first part includes the sum of the first RI and the second RI (or the second RI), the second CRI, and some or all of the second CQI. The second part includes a part or all of the first CRI, the first RI, the first CQI, the first PMI, the second PMI. The CSI may be divided into three. The third part is also called the third part (part 3, CSI part 3). The third part has a lower priority than the second part. At this time, the first part is the sum of the first RI and the second RI (or the second RI), the second CRI, the first CRI and the CQI based on the second CRI (or the second CQI). ) Including part or all. The second part includes a part or all of the first CRI, the first RI, and the first CQI. The third part includes a first PMI, a part or all of the second PMI.

The terminal device may be divided into two parts for each of the CSI based on the first CRI and the CSI based on the second CRI and reported. The two parts of CSI based on the first CRI are also referred to as the first part 1 and the first part 2. Further, the two parts of CSI based on the second CRI are also referred to as the second part 1 and the second part 2. The first part 1 includes a part or all of the first CRI, the first RI, and the first CQI. The first part 2 also includes a first PMI. The second part 1 also includes a part or all of the second CRI, the second RI, and the second CQI. The second part 2 also includes a second PMI. The priority of CSI can be set higher in the order of the second part 1, the first part 1, the second part 2, and the first part 2. At this time, the terminal device will report a long-period (small change) CSI in the second CRI and the first CRI, and the base station device and the terminal device will report the minimum regarding the first CRI and the second CRI. Communication can be performed using the parameters of the limit. Further, the priority of CSI can be set higher in the order of the second part 1, the second part 2, the first part 1, and the first part 2. At this time, the terminal device preferentially reports the complete CSI in the second CRI, so that the base station device and the terminal device can communicate using detailed parameters related to the second CRI.

The terminal device 4A may receive an interference signal (adjacent cell interference) from an adjacent cell in addition to the serving cell. The interference signal is a PDSCH, PDCCH, or reference signal of an adjacent cell. In this case, the removal or suppression of the interference signal in the terminal device is effective. E-MMSE (Enhanced-Minimum Mean Square Error) that estimates the channel of the interference signal and suppresses it with linear weights, an interference canceller that creates a replica of the interference signal and removes it, and a desired signal as a method of removing or suppressing the interference signal. MLD (Maximum Likelihood Detection) that searches all the transmission signal candidates of the interference signal and detects the desired signal, R-MLD (Reduced complexity --MLD) that reduces the transmission signal candidates and makes the calculation amount lower than MLD Applicable. In order to apply these methods, it is necessary to estimate the channel of the interference signal, demodulate the interference signal, or decode the interference signal. Therefore, in order to efficiently remove or suppress the interference signal, the terminal device needs to know the parameters of the interference signal (adjacent cell). Therefore, the base station device can transmit (set) assist information including the parameters of the interference signal (adjacent cell) to the terminal device in order to support the removal or suppression of the interference signal by the terminal device. One or more assist information is set. Assist information includes, for example, physical cell ID, virtual cell ID, power ratio of reference signal to PDSCH (power offset), scrambling identity of reference signal, QCL information (quasi co-location information), CSI-RS resource setting, CSI. -R
One of S antenna port number, subcarrier interval, resource allocation particle size, resource allocation information, DMRS setting, DMRS antenna port number, number of layers, TDD DL / UL configuration, PMI, RI, modulation method, MCS (Modulation and coding scheme) Includes part or all. The virtual cell ID is an ID virtually assigned to the cell, and there may be cells having the same physical cell ID but different virtual cell IDs. QCL information is information about a QCL for a given antenna port, a given signal, or a given channel. In two antenna ports, if the long interval characteristic of the channel carrying the symbol on one antenna port can be inferred from the channel carrying the symbol on the other antenna port, then those antenna ports are QCLs. Is called. Long interval characteristics include delay spreads, Doppler spreads, Doppler shifts, average gains, average delays, spatial receive parameters, and / or spatial transmit parameters. That is, if the two antenna ports are QCLs, the terminal device can be considered to have the same long section characteristics at those antenna ports. The subcarrier spacing indicates a candidate for the subcarrier spacing of the interfering signal, or a subcarrier spacing that may be used in that band. If the subcarrier interval included in the assist information and the subcarrier interval used for communication with the serving cell are different, the terminal device does not have to remove or suppress the interference signal. Candidates for subcarrier spacing that may be used in that band may indicate commonly used subcarrier spacing. For example, the normally used subcarrier interval does not have to include the low frequency subcarrier interval used for high reliability and low delay communication (emergency communication). The resource allocation particle size indicates the number of resource blocks for which precoding (beamforming) does not change. The DMRS settings indicate the PDSCH mapping type, additional placement of DMRS. DMRS resource allocation varies depending on the PDSCH mapping type. For example, in PDSCH mapping type A, DMRS is mapped to the third symbol of the slot. Also, for example, PDSCH mapping type B is mapped to the first OFDM symbol of the allocated PDSCH resource. The additional arrangement of DMRS indicates whether or not there is an additional DMRS arrangement, or the arrangement to be added. Note that some or all parameters included in the assist information are transmitted (set) by signals of the upper layer. In addition, some or all parameters included in the assist information are transmitted as downlink control information. Further, when each parameter included in the assist information indicates a plurality of candidates, the terminal device blindly detects a suitable one from the candidates. Further, the terminal device blindly detects the parameters not included in the assist information.

When the terminal device communicates using a plurality of reception beam directions, the surrounding interference situation changes greatly depending on the reception beam direction. For example, an interference signal that was strong in one receiving beam direction may be weakened in another receiving beam direction. The assist information of the cell, which is unlikely to cause strong interference, is not only meaningless, but also may cause unnecessary calculation when determining whether or not a strong interference signal is received. Therefore, it is desirable that the assist information is set for each reception beam direction. However, since the base station device does not necessarily know the reception direction of the terminal device, it is sufficient to associate the information related to the reception beam direction with the assist information. For example, since the terminal device can associate the CRI with the reception beam direction, the base station device can transmit (set) one or more assist information for each CRI. Further, since the terminal device can associate the time index of the synchronization signal block with the reception beam direction, the base station device can transmit (set) one or more assist information for each time index of the synchronization signal block. .. Further, since the terminal device can associate the PMI (antenna port number) with the reception beam direction, the base station device can transmit (set) one or more assist information for each PMI (antenna port number). .. Further, when the terminal device includes a plurality of sub-arrays, the receiving beam direction is likely to change for each sub-array, so that the base station device transmits (sets) one or more assist information for each index related to the sub-array of the terminal device. )can do. Further, when a plurality of base station devices (transmission / reception points) and a terminal device communicate with each other, the terminal device is likely to communicate in a reception beam direction different from that of each base station device (transmission / reception point). Therefore, the base station apparatus transmits (sets) one or a plurality of assist information for each information indicating the base station apparatus (transmission / reception point). The information indicating the base station device (transmission / reception point) may be a physical cell ID or a virtual cell ID. When different DMRS antenna port numbers are used for the base station device (transmission / reception point), the information indicating the DMRS antenna port number and the DMRS antenna group becomes the information indicating the base station device (transmission / reception point).

The number of assist information set by the base station apparatus for each CRI can be the same. Here, the number of assist information refers to the type of assist information, the number of elements of each assist information (for example, the number of cell ID candidates), and the like. Further, a maximum value is set for the number of assist information set by the base station apparatus for each CRI, and the base station apparatus can set the assist information in each CRI within the range of the maximum value.

If the receiving beam direction of the terminal device changes, it is highly possible that the transmitting antenna is not a QCL. Therefore, the assist information can be associated with the QCL information. For example, when the base station apparatus transmits (sets) assist information of a plurality of cells, a cell that is a QCL (or a cell that is not a QCL) can be instructed to the terminal apparatus.

The terminal device removes or suppresses the interference signal by using the assist information associated with the CRI used for communication with the serving cell.

Further, the base station apparatus has assist information associated with the reception beam direction (CRI / synchronous signal block time index / PMI / antenna port number / sub-array) and the reception beam direction (CRI / synchronous signal block time index / PMI / Assist information that is not associated with the antenna port number / sub array) may be set. Further, the assist information associated with the reception beam direction and the assist information not associated with the reception beam direction may be selectively used in the capabilities and categories of the terminal device. The capabilities and categories of the terminal device may indicate whether the terminal device supports receive beamforming. Further, the assist information associated with the reception beam direction and the assist information not associated with the reception beam direction may be selectively used in the frequency band. For example, the base station apparatus does not set the assist information associated with the received beam direction at frequencies lower than 6 GHz. Further, for example, the base station apparatus sets the assist information associated with the reception beam direction only at a frequency higher than 6 GHz.

The CRI may be associated with the CSI resource set setting ID. When instructing the terminal device to CRI, the base station apparatus may instruct CRI together with the CSI resource set setting ID. When the CSI resource set setting ID is associated with one CRI or one reception beam direction, the base station apparatus may set assist information for each CSI resource set setting ID.

The base station device requests the terminal device to measure the adjacent cell in order to know the adjacent cell related to the reception beam direction of the terminal device. The adjacent cell measurement request includes information related to the reception beam direction of the terminal device and the cell ID. When the terminal device receives the adjacent cell measurement request, it measures RSRP / RSRQ / RSSI of the adjacent cell and reports it to the base station device together with the information related to the reception beam direction of the terminal device. The information related to the reception beam direction of the terminal device is information indicating the CRI, the time index of the synchronization signal block, the sub-array of the terminal device, or the base station device (transmission / reception point).

In addition, when the terminal device moves, the surrounding environment may change from moment to moment. Therefore, it is desirable that the terminal device observes the surrounding channel status, interference status, etc. at a predetermined timing and reports it to the base station device. Report results will be reported in regular or event reports. In the case of periodic reporting, the terminal device periodically measures and reports the synchronization signal or RSRP / RSRQ by CSI-RS. In the case of reporting by event, the event ID and the condition related to the report are associated. The event ID includes, for example, the following, and a threshold value (threshold value 1, threshold value 2 if necessary) and an offset value required for calculating the condition are also set.
Event A1: When the measurement result of the serving cell becomes better than the set threshold value.
Event A2: When the measurement result of the serving cell becomes worse than the set threshold value.
Event A3: When the measurement result of the adjacent cell becomes better than the set offset value than the measurement result of PCell / PSCell.
Event A4: When the measurement result of the adjacent cell becomes better than the set threshold value.
Event A5: When the measurement result of PCell / PSCell becomes worse than the set threshold value 1 and the measurement result of the adjacent cell becomes better than the set threshold value 2.
Event A6: When the measurement result of the adjacent cell becomes better than the set offset value than the measurement result of SCell.
Event C1: When the measurement result with the CSI-RS resource becomes better than the set threshold value.
Event C2: When the measurement result of the CSI-RS resource is better than the measurement result of the set reference CSI-RS resource by an offset amount or more.
Event D1: When the measurement result of a CSI-RS resource different from CRI becomes better than the set threshold.
Event D2: When the measurement result of the CSI-RS resource associated with CRI becomes worse than the set threshold value.
Event D3: When the measurement result of the reception beam direction not related to CRI becomes better than the set threshold value.
Event D4: When the measurement result of the SS block index used for synchronization becomes worse than the set threshold value.
Event D5: When the measurement result of the SS block index not used for synchronization becomes worse than the set threshold value.
Event E1: When the time elapsed since the base station device determines the beam exceeds the threshold value. Event E2: When the time elapsed since the terminal device determines the beam exceeds the threshold value.

When reporting based on the reporting settings, the terminal device reports SS-RSRP / SS-RSRQ / CSI-RSRP / CSI-RSRQ / RSSI as the measurement result.

FIG. 5 shows an example of an uplink communication system according to the present embodiment. The communication system shown in FIG. 5 includes a base station device 7A, a base station device 9A, and a terminal device 6A. The terminal device 6A can use the base station device 7A and / or the base station device 9A as a serving cell. When the base station device 7A or the base station device 9A is provided with a large number of antennas, the large number of antennas can be divided into a plurality of sub-arrays (panels, sub-panels), and transmission / reception beamforming can be applied to each sub-array. In this case, each sub-array may be provided with a communication device, and the configuration of the communication device is the same as the base station device configuration shown in FIG. 2 unless otherwise specified. Further, when the terminal device 6A includes a plurality of antennas, the terminal device 6A can transmit or receive by beamforming. Further, when the terminal device 6A includes a large number of antennas, the large number of antennas can be divided into a plurality of sub-arrays (panels, sub-panels), and different transmission / reception beamforming can be applied to each sub-array. Each sub-array can be provided with a communication device, and the configuration of the communication device is the same as the terminal device configuration shown in FIG. 3 unless otherwise specified. The base station device 7A and the base station device 9A are also simply referred to as a base station device. The terminal device 6A is also simply referred to as a terminal device.

In the uplink, SRS is used to determine the suitable transmit beam for the terminal equipment and the suitable receive beam for the base station equipment. The base station device can transmit (set) setting information related to SRS by a signal of an upper layer. The configuration information includes one or more SRS resource set settings. The SRS resource set setting includes an SRS resource set setting ID and / or one or more SRS resource settings. The SRS resource set setting ID is used to specify the SRS resource set setting. SRS resource settings include SRS resource setting ID, number of SRS antenna ports, SRS transmission comb, SRS resource mapping, SRS frequency hopping, SRS resource setting type. The SRS resource setting ID is used to specify the SRS resource setting. The SRS transmit comb indicates the frequency spacing of the comb tooth spectrum and the position (offset) within the frequency spacing. The SRS resource mapping indicates the OFDM symbol position and the number of OFDM symbols in which the SRS is placed in the slot. The SRS frequency hopping is information indicating the frequency hopping of the SRS. The SRS resource setting type indicates the operation of the SRS resource setting in the time domain. Specifically, the SRS resource setting is a setting to send SRS aperiodically, a setting to send SRS periodically (periodic), or a setting to send SRS semi-persistently. Indicates if there is.

When a plurality of SRS resources are set, the terminal device can determine a suitable SRS resource by transmitting each SRS resource in a different transmission beam direction. If the base station device transmits (instructs) the SRS resource indicator (SRI), which is information indicating the SRS resource, to the terminal device, the terminal device is preferably in the direction of the transmission beam transmitted by the SRS resource. Can be known. The base station apparatus can request the terminal apparatus to transmit the same transmission beam for a predetermined period in order to obtain a suitable reception beam for the base station apparatus. The terminal device transmits in the same transmission beam direction as that transmitted by the instructed SRI with the instructed SRS resource for the instructed period in accordance with the request from the base station apparatus.

When the terminal device includes a plurality of sub-arrays, the terminal device can communicate with a plurality of base station devices (transmission / reception points). In the example of FIG. 5, the terminal device 6A can use the base station device 7A and the base station device 9A as serving cells. In this case, for the terminal device 6A, there is a high possibility that the transmission beam direction suitable for communication with the base station device 7A and the transmission beam direction suitable for communication with the base station device 9A are different. Therefore, if the terminal device 6A transmits in different sub-arrays in different transmission beam directions, the base station device 7A and the base station device 9A can communicate with each other at the same timing.

When transmitting SRS through a plurality of antenna ports in a certain SRS resource, the terminal device can use different transmission beam directions for each antenna port. In this case, if the base station device instructs the terminal device to transmit at a suitable antenna port number, the terminal device can know the suitable transmission beam direction. The base station device can also instruct the terminal device to transmit PMI (TPMI) by using a codebook for selecting an antenna port. The base station device can instruct the terminal device which codebook to refer to. The terminal device can refer to the indicated codebook and use the transmit beam direction corresponding to the antenna port number indicated by TPMI.

When the terminal device includes a plurality of sub-arrays and can transmit at the same timing in the plurality of sub-arrays, different antenna port numbers can be assigned to the sub-arrays. At this time, if the terminal device transmits SRS using the transmission beam from antenna ports having different sub-arrays and receives TPMI from the base station device, the terminal device can know the suitable sub-array and transmission beam direction. Therefore, the terminal device can associate the TPMI with the sub-array and the transmission beam direction.

When the terminal device communicates with a plurality of base station devices (transmission / reception points), the same signal (data) can be transmitted to each base station device (transmission / reception point), and different signals (data) can be transmitted. Can be sent. When the terminal device communicates with multiple base station devices (transmission / reception points) using the same signal (data), the signals received by the multiple base station devices (transmission / reception points) should be combined to improve the reception quality. Therefore, it is desirable that a plurality of base station devices (transmission / reception points) cooperate to perform reception processing.

The base station apparatus can use DCI for scheduling PUSCH. When the terminal device communicates with a plurality of base station devices, each base station device can transmit a DCI for scheduling PUSCH. The DCI includes SRI and / or TPMI, and the terminal device can know the transmission beam suitable for the base station device. Further, when the terminal device communicates with a plurality of base station devices, PUSCH can be transmitted to the plurality of base station devices by DCI from one base station device. For example, when DCI contains control information for a plurality of layers (codeword, transport block) and SRI and / or TPMI is instructed (set) for each layer, each layer is a base station apparatus. It is transmitted with a transmission beam suitable for. As a result, when one DCI is received, the terminal device can transmit different signals (data) to a plurality of base station devices. Further, when DCI includes control information of one layer and a plurality of SRIs and / or TPMIs are instructed (set) for one layer, the terminal device uses different transmission beams for one layer (same). Data) is sent. As a result, when one DCI is received, the terminal device can transmit the same signal (data) to a plurality of base station devices.

When the terminal device transmits to a plurality of base station devices at the same timing, it is desirable that each base station device knows the communication quality with the terminal device at the same timing. Therefore, the base station apparatus can instruct (trigger) a plurality of SRIs and SRS resources corresponding to each SRI with one DCI. That is, if the terminal device transmits the SRS in the transmission beam direction corresponding to each SRI at the same timing, each base station device can know the communication quality with the terminal device at the same timing.

When the sub-array provided in the terminal device uses only one transmission beam direction at the same timing, transmission is performed to a plurality of base station devices at the same timing with different sub-arrays. At this time, when two SRIs are instructed (set) by one DCI from the base station device, if the two SRIs are associated with the same sub-array, the terminal device transmits the transmission corresponding to the two SRIs at the same timing. It may not be possible to execute. In order to avoid this problem, for example, the base station apparatus can set a plurality of SRS resources by grouping them, and within the group, the terminal apparatus can be requested to transmit the SRS using the same sub-array. Further, if different sub-arrays are used between groups, the base station apparatus can know a plurality of SRIs that can be set at the same timing. The group of SRS resources may be an SRS resource set. The SRS (SRS resource) that can be set at the same timing may not be a QCL. At this time, the terminal device can transmit the SRS in association with the QCL information. For example, if the terminal device transmits the SRS that is the QCL and the SRS that is not the QCL separately, the base station device does not set the SRI that is the QCL at the same timing, and the SRI that is not the QCL is set at the same timing. Can be done. Further, the base station device may request SRS for each sub-array of the terminal device. In this case, the terminal device transmits SRS for each sub array.

When two SRIs that the terminal device cannot transmit at the same timing are instructed by the base station device, the terminal device performs a beam recovery procedure for selecting the transmission beam again for the base station device. Can be requested. The beam recovery procedure is a procedure performed when the transmission / reception beam is out of tracking between the terminal device and the base station device and the communication quality is significantly deteriorated. The terminal device is connected to a new connection destination (base) in advance. It is necessary to acquire the transmission beam of the station equipment). In the terminal device according to the present embodiment, the transmission beam itself is secured, but the beam recovery procedure is performed in order to eliminate the state in which two SRIs that cannot be transmitted at the same timing are set. Can be used.

The terminal device according to the present embodiment can include a plurality of antennas (antenna panels) in which independent beamforming is set. The terminal device according to the present embodiment can use a plurality of antenna panels. Of course, the terminal device can be used by switching the plurality of antenna panels, but if the antenna panels are not properly selected, the transmission quality is significantly deteriorated, especially in high frequency transmission. Therefore, the terminal device can perform beam scanning (exploration) with the base station device in order to select the beamforming set on the antenna. The terminal device according to this embodiment can transmit SRS to perform the beam scanning.

The base station apparatus according to the present embodiment can notify the terminal apparatus of information indicating duality (relationship, reciprocity) regarding the propagation (channel) characteristics of the downlink and the uplink. As information regarding the propagation characteristics, the base station apparatus can notify the terminal apparatus of information indicating beam correspondence (Beam Correspondence, spatial relation, spatial relation information, reception parameter). Here, the beam correspondence includes the reception beam forming (spatial area reception filter, reception weight, reception parameter, reception space parameter) used when the terminal device receives the downlink signal, and the transmission used when transmitting the uplink signal. Contains information indicating the relevance to beam forming (spatial region transmit filters, transmit weights, transmit parameters, transmit spatial parameters).

The base station device can set beam correspondence for each signal transmitted by the terminal device. For example, the base station device can notify the terminal device of information indicating the beam correspondence to the SRS transmitted by the terminal device. The base station device can notify the terminal device of SRS space-related information (SRS-SpatialRelationInfo). When the SRS space-related information indicates a predetermined signal (value, state), the terminal device can transmit the SRS by using the beamforming associated with the predetermined signal. For example, when the SRS space-related information specifies a sync signal (SSB and PBCH), the terminal device can transmit the SRS using the receive beamforming used to receive the sync signal. Similarly, the base station device has spatially related information about other signals transmitted by the terminal device (eg, PUCCH / PUSCH / RS / RACH, etc.) and other signals received by the terminal device (eg, PDCCH / PDSCH / RS). Can be notified. That is, the base station device can notify the terminal device of the space-related information of the first signal and the second signal. When the terminal device receives the space-related information of the first signal and the second signal, and recognizes that the space-related information guarantees the space-related relationship between the first signal and the second signal. , The reception parameter that received the first signal (or the transmission parameter that transmitted the first signal) can be used to transmit (or receive the second signal) the second signal.

The QCL includes at least the following four types, each of which has different parameters that can be regarded as the same. The base station device and the terminal device can set any one of the following QCL types between the antenna ports (or the signal associated with the antenna port), or can set a plurality of QCL types at the same time. it can.
QCL type A: Doppler shift, Doppler spread, average delay, delay spread
QCL type B: Doppler shift, Doppler spread
QCL type C: Doppler shift, average delay
QCL type D: Spatial Rx

The terminal device can set receive beamforming to receive the PDSCH when the PDSCH resource is scheduled using the downlink assignment. At this time, the terminal device can acquire the information associated with the received beamforming from the DCI in which the downlink assignment is described. For example, the terminal device can obtain a transmission configuration indication (TCI) from the DCI. The TCI indicates the information associated with the QCL associated with the antenna port to which the PDSCH was transmitted. The terminal device can set the receive beamforming for receiving the PDSCH (or DMRS associated with the PDSCH) by reading the TCI. For example, when the DMRS associated with the SSB and PDSCH is set to QCL with respect to the reception parameter in TCI, the terminal device receives the receive beam used when receiving the SSB of the index fed back to the base station device, and receives the PDSCH. Can be used for. If the DCI is not acquired in time before the terminal device starts receiving the PDSCH (before the frame including the PDSCH is received by the terminal device), the scheduling offset value indicating the time difference between the scheduling information and the PDSCH is (If it is less than a predetermined value), the terminal device can receive the PDSCH according to the default setting of TCI default. In addition, TCI-defoult is one of eight TCIs set. Further, when receiving PDCCH, the terminal device can set the received beamforming based on the setting of TCI default.

Further, in order to determine a suitable transmission beam of a base station apparatus, a codebook in which candidates for a predetermined precoding (beamforming) matrix (vector) are defined is used. The base station device transmits CSI-RS, and the terminal device obtains a suitable precoding (beamforming) matrix from the codebook and reports it to the base station device as PMI. As a result, the base station apparatus can know the transmission beam direction suitable for the terminal apparatus. The codebook has a precoding (beamforming) matrix for synthesizing antenna ports and a precoding (beamforming) matrix for selecting antenna ports. When using a codebook for selecting antenna ports, the base station apparatus can use different transmission beam directions for each antenna port. Therefore, if the terminal device reports a suitable antenna port as the PMI, the base station device can know the suitable transmission beam direction. The suitable reception beam of the terminal device may be the reception beam direction associated with the CRI, or the suitable reception beam direction may be determined again. When using a codebook that selects an antenna port, if the preferred receive beam direction of the terminal device is the receive beam direction associated with the CRI, then the receive beam direction that receives the CSI-RS is the receive beam associated with the CRI. It is desirable to receive in the direction. The terminal device can associate the PMI with the received beam direction even when the received beam direction associated with the CRI is used. Further, when a codebook for selecting an antenna port is used, each antenna port may be transmitted from a different base station device (cell). In this case, if the terminal device reports the PMI, the base station device can know which base station device (cell) is suitable for communication quality. In this case, it can be said that the antenna ports of different base station devices (cells) are not QCLs.

The terminal device according to the present embodiment notifies the base station device of a plurality of PMIs. The terminal device according to the present embodiment can notify the base station device of PMI1 which is the first PMI and PMI2 which is the second PMI.

The PMI1 can be a PMI11 which is an eleventh PMI, a PMI12 which is a twelfth PMI, a PMI13 which is a thirteenth PMI, and a PMI14 which is a fourteenth PMI.

The PMI 11 can be further composed of q1 (111th PMI, PMI111) which is an element related to the first dimension and q2 (112th PMI, PMI112) which is an element related to the second dimension. q1 can indicate an orthogonal matrix referenced by v, which is a vector of the first dimension. The orthogonal matrix referred to by v is a DFT matrix given by the number N1 of CSI-RS ports of the first dimension provided in the base station apparatus, and the base station apparatus has the DFT matrix with respect to the first dimension. Oversampling can be performed by the number of oversamplings O1. This means that there is only one O1 orthogonal matrix referred to by v, so q1 is an index indicating the orthogonal matrix referred to by v among the O1 orthogonal matrices. On the other hand, q2 is an index related to the orthogonal matrix referred to by u, which is a vector of the second dimension. The base station apparatus can oversample the DFT matrix given by the number N2 of CSI-RS ports in the second dimension by the number of oversamplings O2 for the second dimension. q2 is an index indicating the orthogonal matrix referred to by v among the O2 orthogonal matrices. When the terminal device provides feedback assuming a plurality of layers, the orthogonal matrix indicated by the PMI 11 can be shared among the layers. The terminal device according to the present embodiment can also notify the PMI 11 for each layer.

The PMI 12 can be an index indicating at least one of a plurality of vectors included in the matrix selected by the PMI 11. The terminal device can notify the base station device of a vector given by the Kronecker product of v, which is a vector of the first dimension, and u, which is a vector of the second dimension. Since u and v are vectors selected from DFT matrices of size N1 and size N2, respectively, there are only N1 × N2 vector candidates given by the Kronecker product of v and u. Further, the terminal device according to the present embodiment can feed back a plurality of vectors given by the Kronecker product of v and u to the base station device. The number of vectors that can be fed back by the terminal device is set by the base station device by L1 (L1, first value) indicating the number of first vectors. L1 can be notified to the terminal device by signaling in the upper layer. Therefore, the candidate vector combinations that the terminal device feeds back to the base station device are C (N1N1) when C (x, y) is a combination function that indicates the number of combinations when only y are selected from the population x. , L) only exists. The PMI 12 can be an index indicating any one of the vector combination candidates existing only in C (N1N1, L). The base station apparatus according to the present embodiment may be provided with a polarized antenna, but the vector selected by the PMI 12 can be common. Further, as with PMI 11, the terminal device can be shared between layers for PMI 12. The terminal device can also notify the PMI 12 between layers.

The base station apparatus can set the value of L1 based on the number of ports of CSI-RS. As will be described later, the base station apparatus can also set the value of L1 based on information other than the number of CSI-RS ports.

The PMI 13 can be an index indicating the strongest vector for the terminal device among the L1 vectors notified by the PMI 12. Further, when the base station apparatus is provided with a polarization antenna, it is an index indicating the strongest vector among the 2 × L1 vectors including the polarization interval. The terminal device can notify the base station device of the PMI 13 layer by layer. The terminal device according to the present embodiment can also select one layer and notify the strongest vector in the layer. In this case, the terminal device can also notify the base station device of the selected layer. The terminal device can also always notify the strongest vector in layer 1.

The PMI 14 is an index indicating an amplitude coefficient that can be multiplied by one L1 vector specified by the PMI 12. Since the PMI 14 can also calculate the amplitude coefficient for each polarization, in this case, the PMI 14 is an index indicating the amplitude coefficient to be multiplied by (2 × L1) vectors.

The amplitude coefficient can be a divided value of a predetermined particle size between 0 and 1. For example, the terminal device according to this embodiment uses 3-bit information to be 0, 64-1 ^/2 , 32-1 ^{/ 2} ,
16 ^{-1/2, 8 -1/2,} 4 ^{-1/2, 2 -1/2,} either 1, as an amplitude coefficient for (2 × L1) number of vectors indicated PMI12, the base station apparatus You can notify. The terminal device can notify the PMI 14 for each layer. Further, the terminal device according to the present embodiment can notify the PMI 14 as a common value among the layers. The PMI 14 has (2L-1) elements (k ⁽¹⁾ ₀ (14 (0) PMI, PMI 14 (0)), k ⁽¹⁾ ₁ (14th ⁾ indicating the amplitude coefficient of each vector indicated by the PMI 12. It can be composed of PMI of (1), PMI14 (1), ..., k ⁽¹⁾ _2L-1 (PMI of 14th (2L-1), PMI14 (2L-1)). Each element can be defined for each layer.

The PMI 21 can indicate the phase coefficients for the (2 × L1) vectors indicated by the PMI 12. The phase coefficient can be an angle obtained by dividing an angle of 360 ° into a predetermined particle size. For example, when 360 ° is divided into four, the terminal device can notify the base station device of any one of the phase coefficients indicating the four angles of 0 °, 90 °, 180 °, and 270 ° as the phase coefficient. .. The base station device can notify the terminal device of the NPSK as a value indicating the particle size of the phase coefficient. The base station apparatus can notify any one of 2, 4 and 8 as NPSK. The terminal device can notify the base station device of the PMI 21 layer by layer. Further, the terminal device can notify the base station device of a value common to the layers of the PMI 21.

The PMI 22 can represent the amplitude coefficients for the (2 × L1) vectors indicated by the PMI 12. The PMI 14 can also show the amplitude coefficient, but the PMI 22 can show the amplitude coefficient for each subband. Therefore, the terminal device can feed back the PMI 22 when the base station device requests feedback of the CSI for each subband. The terminal device can notify the base station device of the PMI 22 layer by layer. Further, the terminal device can notify the base station device of a value common to the layers of the PMI 22. The PMI 22 has (2L-1) elements (k ⁽²⁾ ₀ (PMI of the 22nd (0), PMI 22 (0)), k ⁽²⁾ ₁ (22nd ⁾ indicating the phase coefficient of each vector indicated by the PMI 12. The PMI of (1), PMI22 (1), ..., k ⁽¹⁾ _2L-1 (PMI of 22nd (2L-1), PMI22 (2L-1)) can be composed of PMI22. Each constituent element can be defined for each layer.

The terminal device according to the present embodiment can notify the base station device of a rank index (RI) indicating a desirable number of layers for the own device as a CSI. The terminal device according to the present embodiment can change the feedback of the PMI based on the value of RI notified to the base station device.

The terminal device notifies RI / CQI / PMI suitable for its own device based on a reference signal such as NZP-CSI-RS. When the terminal device feeds back the RI for which RI> 1, the terminal device feeds back the PMI corresponding to the number of RIs to the base station device. If the PMI is not fed back, the PMI does not have to be fed back even when RI> 1. The feedback of RI such that RI> 1 by the terminal device to the base station device suggests that the propagation environment is an environment in which high throughput can be expected, but at the same time, the overhead related to the feedback of PMI and CQI increases. It means that there is a possibility that it will end up.

The terminal device can feed back the above-mentioned PMI and CQI for each subband. Since the terminal device feeds back PMI and CQI for each subband, the base station device can acquire highly accurate propagation path state information even in a propagation path environment having frequency selectivity. However, when the number of subbands is N3, it means that the amount of information fed back by the terminal device is simply N3 times. In particular, PMI has a large amount of information to be fed back as described above, and an increase in the amount of feedback information due to feedback for each subband cannot be ignored.

Therefore, in the terminal device according to the present embodiment, it is possible to compress the PMI in the frequency domain and feed it back by utilizing the fact that the channel having the frequency selection has a certain degree of frequency correlation. The terminal device applies an inverse discrete Fourier transform to the propagation path response estimated in the frequency domain, so that the propagation path response is converted into an impulse response of the propagation path. Since the impulse response of the propagation path is less than the maximum delay time of the delayed wave, the amount of feedback information is compressed by feeding back the impulse response in question rather than feeding back the propagation path response estimated in the frequency domain as it is. Can be done. Hereinafter, compressing the amount of information by performing a predetermined conversion on the frequency response of the propagation path is also described as frequency domain compression (FD compression).

The following examples can be considered as a method of performing FD compression on the above-mentioned PMI. The terminal device multiplies the PMI calculated for each of the N3 subbands by an orthogonal basis of size N3. The orthogonal basis assumed here is not limited to anything, but the case where the discrete Fourier transform matrix (DFT) matrix Wf is used will be described below as an example. As a matter of course, if it is a matrix composed of information agreed between the base station device and the terminal device, the Wf assumed by the present embodiment can be used. For example, a DCT matrix or a Walsh matrix can be used.

In the following description, compression in the frequency domain is assumed, but the dimension in which the PMIs are arranged is not limited to the frequency direction. The terminal device according to the present embodiment also holds the method of the present embodiment by applying an orthogonal basis to a matrix generated by arranging PMIs in dimensions in the temporal direction or the spatial direction, for example.

Now, W calculated by the terminal device by W1 and W2 is a vector of 2N1N2 rows and 1 column, assuming that the number of ranks is 1. The terminal device feeds back the PMI1 and PMI2 described above in order to feed W to the base station device. When the terminal device calculates W for N3 subbands and arranges them in the column direction, it naturally becomes a matrix Wa of 2N1N2 rows and N3 columns. Here, the terminal device multiplies Wa by Wf. Then, of course, WaWf becomes a matrix of 2N1N2 rows and N3 columns. However, the amount of feedback information is not compressed if the terminal device simply feeds back WaWf. However, as described above, the frequency response of the propagation path has a certain degree of frequency correlation. Moreover, since the frequency correlation is determined by the delay profile of the propagation path, it is common among the antenna ports. This means that the power of WaWf does not spread over the entire response of WaWf, but is concentrated in a part of it. Therefore, the terminal device efficiently feeds back the information contained in Wa while compressing the amount of Fordback information by feeding back only M (<N3) responses of WaWf to the base station device. be able to. The terminal device notifies the basis of Wf (that is, M vectors) corresponding to the feedback M responses, so that the base station apparatus can acquire Wa from the fed back WaWf.

However, when the rank number RI of the CSI fed back by the terminal device increases, the amount of feedback information increases even if FD compression is performed. Therefore, the base station device and the terminal device according to the present embodiment can control the information related to the feedback based on the RI fed back by the terminal device.

The accuracy of CSI that can be grasped by the base station device depends on the size of M. Of course, if the size of M is large, the base station apparatus can grasp the CSI with high accuracy, but the amount of feedback information increases. Therefore, the base station device and the terminal device according to the present embodiment control RI by the size of M (also referred to as FD unit size).

The base station device can notify the terminal device of the size of M by signaling of the upper layer (for example, RRC signaling) or downlink control information (for example, DCI or aperiodic CSI trigger). .. The FDunit size set by the base station apparatus in this way is also referred to as M1. When the acquired size of M1 exceeds a predetermined value or matches a predetermined predetermined value, the terminal device sets the feedback RI to a predetermined value or less or a predetermined value. be able to.

Further, in the terminal device according to the present embodiment, even if there is a value of M1 set by the base station device, the value of M can be changed by the RI fed back by the terminal device. For example, the base station device can be set in the terminal device as M1 and FD unit size as shown above, but the terminal device is quasi-static when the feedback RI exceeds a predetermined value. Alternatively, instead of the dynamically set M1, the value M0 which is fixedly agreed with the base station device in advance can be used. However, when the number of ranks of the terminal device exceeds a predetermined value, it is preferable to reduce the value of M. Therefore, the terminal device is quasi-statically or dynamically set from the preset value M0 from the base station device. When M1 is small, the terminal device can use M1 as the FD unit size instead of M0. By controlling in this way, it is possible to prevent the amount of feedback information from increasing when the terminal device performs high-rank CSI feedback.

The base station apparatus according to the present embodiment can limit the number of ranks to be considered when the terminal apparatus gives feedback to the terminal apparatus. The base station device can limit the number of ranks considered by the terminal device by signaling in the upper layer (for example, typeII-RI Restriction (hereinafter, also referred to as RI restriction or RI restriction information)). On the other hand, the base station apparatus can notify the terminal apparatus of L1 by signaling of an upper layer such as RRC.

Therefore, in the base station apparatus according to the present embodiment, when the codebook setting indicates a type 2 codebook, the value of L1 can be set according to the upper limit of the number of ranks considered by the terminal apparatus. That is, the upper limit of the value of L1 that can be notified by the base station device changes depending on whether or not the number of ranks considered by the terminal device exceeds a predetermined value. For example, if the base station device sets the upper limit of the number of ranks considered by the terminal device to 2 by signaling of the upper layer (for example, codebook setting), the base station device may set the upper limit of the value of L1 to 4. You can. When the base station device sets the upper limit of the number of ranks considered by the terminal device to 4 by signaling (codebook setting) of the upper layer, the base station device can set the upper limit of the value of L1 to 2.

Further, the terminal device can acquire (determine) the value of L1 from the base station device by signaling in the upper layer. The terminal device according to the present embodiment can read the value of L1 according to the value of RI to be fed back. That is, the terminal device uses the value itself notified by the base station device or is notified by the base station device for the value of L1 to be considered based on whether or not the value of RI to be fed back exceeds a predetermined value. It is possible to decide whether to use a value smaller than the value (second L value, second value). For example, consider a case where the terminal device is set to 4 as the value of L1 from the base station device. Then, when the predetermined value is 2, when the terminal device feeds back a value such that RI <3 as RI, the other feedback values are calculated with reference to the value of L1, but the terminal device performs RI. When feeding back a value such that RI> 2, other feedback values can be calculated as a second L value (that is, a value smaller than the L1 value notified from the base station apparatus).

Whether or not the method of limiting the value of L by the value of RI is set by the maximum value of RI or the maximum value of L1 can be selected. Hereinafter, the same can be applied to any of the methods described in the present embodiment.

By feeding back the PMI 11, the terminal device can notify the base station device of the information referred to by the terminal device. For example, the PMI 11 can notify the base station apparatus of a matrix composed of a plurality of vectors. The base station apparatus can limit the information referred to by the PMI 11 by signaling in the upper layer. For example, when there are four patterns of PMI 111 candidates (that is, matrix candidates) constituting PMI 11, the base station apparatus bitmaps the terminal apparatus with candidates that do not need to be considered among the four patterns. Can be notified by.

The base station apparatus according to the present embodiment can further limit the information itself notified by the PMI 11. For example, when the PMI 11 indicates a matrix composed of a plurality of vectors, the base station apparatus uses signaling (or a control signal such as DCI) of an upper layer to form a matrix of the plurality of vectors. Among them, candidates that the terminal device does not need to consider can be notified by a bitmap. For example, when the information indicated by the PMI 11 indicates four vectors, the base station apparatus can notify the terminal apparatus of the vector candidates that do not need to be considered among the four vectors by the bitmap. .. Needless to say, when a vector that the terminal device does not need to consider occurs, the amount of information fed back by the terminal device can be reduced based on the vector.

Whether or not the above-mentioned method for limiting the amount of information of PMI 11 is set according to the value of RI fed back by the terminal device or the upper limit value of RI that can be fed back notified by the base station device to the terminal device. May be determined, or may be set for each RI. For example, the terminal device considers the limitation of the amount of information when the limitation relating to PMI 11 is set by the base station apparatus and the RI value notified by the terminal apparatus exceeds a predetermined value (for example, 2). The PMI 11 can be fed back. Further, when the base station apparatus sets the RI limit, when the maximum value of RI set by the RI limit exceeds a predetermined value, the PMI 11 can be fed back in consideration of the limitation of the amount of information. it can.

In addition, the base station apparatus can also limit the candidates for PMI 14 by signaling in the upper layer. The PMI 14 can indicate a coefficient (amplitude coefficient, amplitude weight) to be set for each vector selected by the PMI 12, and the base station apparatus can set the maximum value of the coefficient by signaling in the upper layer.

The terminal device according to the present embodiment can change the maximum value of the coefficient depending on the value of RI to be notified. For example, when the maximum value of the coefficient is set to 1 by signaling from the base station device to the upper layer, the terminal device sets the maximum value of the coefficient to 1 when the value of RI to be notified exceeds a predetermined value. The PMI 14 can be calculated as a smaller value (eg 2- ^(1/2) ) and can be fed back to the base station apparatus.

Further, the base station device can limit the candidate value of the amplitude coefficient that can be fed back by the terminal device, instead of limiting the maximum value of the amplitude coefficient. For example, when eight candidate amplitude coefficients that can be fed back by the terminal device are set, the base station device can limit the candidate values of the amplitude coefficient that the terminal device considers by using an 8-bit bitmap.

Candidate phase factor assistance is feedback PMI21 is determined by the N _PSK the base station apparatus notifies. The base station apparatus as a candidate for _{N PSK,} can be considered {2,4,8}. Depending on the value of N _PSK , the phase difference (angle difference) between the candidate values of the phase coefficient fed back by the terminal device changes, and 360 ° / N _PSK becomes the phase difference.

The base station apparatus can limit the candidates for the phase coefficient considered in the PMI 21. The base station apparatus according to this embodiment, the RI restriction, if the upper limit value of the terminal device is considered RI is above a predetermined value, it is possible to limit the value of N _PSK. For example, the base station apparatus can set the _NPSK value to 4 or less when the RI limit is greater than 2. Further, the terminal device can change the value of _NPSK to be considered when the value of RI to be fed back exceeds a predetermined value. For example, when the value of _NPSK notified by RRC from the base station device is 8, and the value of RI fed back by the terminal device exceeds a predetermined value (for example, 2) (for example, 3). , the value of _{N PSK} as 4 (i.e. less than the value that is notified by RRC), can be calculated and fed back PMI21.

Further, the base station apparatus can also limit the candidates for the phase coefficient considered in the PMI 21 by the bitmap. For example, when the base station device is a N _{PSK = 8,} the 8-bit bitmap, it may be the terminal device to limit the consideration phase coefficients PMI21.

Further, the sub-band that feeds back the phase coefficient may be limited. For example, the base station apparatus can set the frequency density for feeding back the phase coefficient by signaling in the upper layer (for example, a codebook setting). For example, the frequency densities are 1, 2, and 3. When the frequency density is 1, the terminal device feeds back the phase coefficient in all subbands. When the frequency density is 2, the phase coefficient is fed back at a rate of 1 in 2 subbands. When the frequency density is 3, the phase coefficient is fed back at a rate of 1 in 3 subbands. Therefore, if the number of subbands to be fed back is reduced by the frequency density, the amount of feedback information is reduced.

The terminal device can notify the amplitude coefficient for each subband (also referred to as the subband amplitude coefficient) by the PMI 22. However, since the feedback is for each subband, the overhead related to the feedback is extremely large. Therefore, in the base station apparatus according to the present embodiment, it is possible to set whether or not to allow feedback for each subband according to the value of RI notified by the terminal apparatus. That is, the base station apparatus can allow the terminal apparatus to notify the amplitude coefficient for each subband only when the RI value notified by the terminal apparatus is equal to or less than a predetermined value.

Further, the sub-band that feeds back the sub-band amplitude coefficient may be limited. For example, the base station apparatus can set the frequency density for feeding back the subband amplitude coefficient by signaling in the upper layer (for example, a codebook setting). For example, the frequency densities are 1, 2, and 3. When the frequency density is 1, the terminal device feeds back the amplitude coefficient in all subbands. When the frequency density is 2, the amplitude coefficient is fed back at a rate of 1 in 2 subbands. When the frequency density is 3, the amplitude coefficient is fed back at a rate of 1 in 3 subbands. Therefore, if the number of subbands to be fed back is reduced by the frequency density, the amount of feedback information is reduced. The frequency densities of the above-mentioned phase coefficient and subband amplitude coefficient may be the same or different. The frequency density of the subband amplitude coefficient is used when the subband amplitude coefficient is ON in the signaling of the upper layer (for example, codebook setting). When the subband amplitude coefficient is OFF, the amplitude coefficient is not considered in all subbands.

Further, in order to reduce the amount of information, the amplitude coefficient (wideband amplitude coefficient or subband amplitude coefficient) may be common among the spatial layers. For example, if the base station device sets information that makes the amplitude coefficient common between the spatial layers in the signaling of the upper layer (for example, the codebook setting), the terminal device makes one CSI report (however, CSI part 1, CSI part 1, CSI Part 2 includes) reports one amplitude factor.

The information amount reduction method described above is basically set by the base station device quasi-statically by signaling in the upper layer, or is set in advance with the terminal device, that is, is fixedly set. can do. The base station device according to the present embodiment can dynamically notify the terminal device of the information related to the information amount reduction method.

The base station device according to the present embodiment can describe the information related to the information amount reduction method in the trigger that requests the CSI feedback from the terminal device. That is, information related to the information amount reduction method can be described in the DCI that is the trigger for requesting CSI feedback. In addition, the base station device sets a plurality of information amount reduction methods in advance for the terminal device, and sets a plurality of preset information amount reduction methods for the DCI that is a trigger for requesting CSI feedback. Information can be provided that indicates which of these is considered in the relevant CSI feedback.

The base station apparatus according to the present embodiment can notify the terminal apparatus of the elements required for CSI feedback. For example, the base station apparatus can notify the terminal apparatus of information indicating which of the first PMI and each PMI constituting the second PMI is included in the CSI feedback by DCI or higher layer signaling. ..

Regarding the information amount reduction method described above, the base station device can be set in common among the layers for the terminal device, or can be set for each layer. That is, when the terminal device performs CSI feedback with RI = 3, the information amount reduction method is not performed on the PMI corresponding to layer 1 and layer 2, and the information amount reduction method is performed on the PMI corresponding to layer 3. It can be set. The base station device can set whether or not to set the information amount reduction method for each layer for the terminal device, and notifies the terminal device of the maximum number of layers to start considering the information amount reduction method. be able to. When the maximum number of layers for starting consideration of the information amount reduction method is set to, for example, 3, the terminal device does not perform the information amount reduction method for the PMI corresponding to the layer 1 and the layer 2, and the PMI corresponding to the layer 3 is performed. It is possible to set the information amount reduction method.

The base station device can notify the terminal device of L1. Since a large value of L1 means that the number of vectors that can be synthesized increases, it is possible to provide highly accurate CSI feedback, but of course, the overhead related to CSI feedback also increases. Therefore, the base station apparatus according to the present embodiment can set the value of L1 in association with the value associated with other CSI feedback. For example, the base station apparatus can set the value of L1 according to the value of O ₁ (O ₂ ) considered in PMI 111 (PMI 112) and the values of N ₁ and N ₂ considered in PMI 12. For example, the base station apparatus can determine the maximum value of L1 that can be set based on whether or not either or both of N ₁ and N ₂ exceeds a predetermined value.

Incidentally, the number of candidates of selectable vector PMI12 is because would be given by the product of N ₁ and N _2, the value of L1 may be equal to or less than the value of the product of N ₁ and N _2. The base station apparatus according to this embodiment, as the value of L1, can be a value exceeding the value of the product of N ₁ and N _2. This means that the terminal device can select the same vector by PMI12. By setting in this way, the terminal device can flexibly change the amplitude coefficient that can be set for the vector selected by PMI 12 even when the candidate value of the amplitude coefficient fed back by PMI 14 is small (simply think). , Selecting the same vector and simply adding it corresponds to multiplying the vector by the amplitude factor 2). Therefore, even if the feedback amount of the PMI 14 is reduced (for example, the candidate value is reduced by the bitmap), the decrease in the feedback accuracy can be minimized.

Further, the subband size (number of subbands) for which the terminal device calculates PMI can be a value different from the subband size (number of subbands) for which the terminal device calculates CQI. In the base station device, when the number of subbands for which the terminal device calculates CQI is N4, the number of subbands N3 for which the terminal device calculates PMI can be set as N3 = N4 / R. R can be notified to the terminal device. The base station device can be set to R = 2 and the terminal device, in which case the particle size of the frequency at which the terminal device calculates the PMI can be reduced. On the other hand, the value of M considered by the terminal device can also be changed according to the particle size of the frequency at which the terminal device calculates the PMI. For example, the base station apparatus can increase the value of M in proportion to R.

On the other hand, as already described, when the value of M is increased, the amount of information fed back by the terminal device increases. In particular, when the RI is large, the effect is even greater. Therefore, in the terminal device according to the present embodiment, when R is set to a value larger than a predetermined value (for example, R = 1) (for example, R = 2), RI (for example, RI> 2) larger than the predetermined value. It can be set not to give CSI feedback. This is because when the terminal device performs high-rank CSI feedback, it is preferable to set M small in order to suppress the amount of feedback information. When M is made small, even if the frequency particle size of PMI is made small, the efficiency of frequency domain compression is not improved. Therefore, when R is set to a value larger than a predetermined value, the terminal device has a high rank. It is preferable not to provide CSI feedback. The base station device can preset the maximum RI (for example, RI = 2) that the terminal device can feed back when the terminal device is set to R (for example, R = 2) larger than a predetermined value.

Further, the terminal device is different from R0 set by the base station device when the RI of a value larger than the predetermined value is fed back when the predetermined value R0 is set as R by the base station device. The value R1 can be set to R to calculate the CSI feedback. Here, R0 set by the base station device refers to a value set in the terminal device by the signaling of the base station device in the upper layer or the signaling of the physical layer. It is preferable that R1 set by the terminal device has a value smaller than R0. For example, when R0 set by the base station device is 2, and the terminal device feeds back an RI larger than a predetermined value, the terminal device sets R1 smaller than R0 (for example, R1 = 1) to R. The CSI can be calculated. The base station device can set the value of RI for calculating the CSI by the terminal device using R1 in advance with respect to the terminal device.

Further, the terminal device can set R as R = C × 1 / RI. Here, C is a constant, which may be predetermined or may be set from the base station apparatus. By setting in this way, the terminal device can set a small R when feeding back a large RI. The above equation can be set only when notifying an RI larger than a predetermined value. That is, when the terminal device feeds back an RI larger than a predetermined value, the above equation is set, and when the RI is fed back below a predetermined value, the CSI is calculated using R0 set by the base station device. can do.

Further, when the base station device feeds back an RI larger than a predetermined value to the terminal device, the number of subbands for calculating PMI is set so that only the same number of subbands for calculating CQI is assumed. be able to.

Further, when the terminal device assumes a predetermined number or more of RIs, FD compression can be assumed regardless of the presence or absence of signaling from the base station device. In this case, the parameters related to FD compression (for example, the value of M) can be shared with the base station apparatus in advance. Further, when assuming a predetermined signal processing, the terminal device can assume FD compression regardless of the presence or absence of signaling from the base station device. For example, when the terminal device notifies the base station device that it supports predetermined signal processing (for example, signal demodulation considering modulo calculation, signal demodulation considering compressed sensing or turbo equalization), the terminal The device can take FD compression into account when feeding back the CSI.

Further, the terminal device can assume FD compression when a predetermined signal processing is predetermined at the time of feedback of CSI. For example, the terminal device can assume FD compression when feeding back CSI assuming spatial multiplexing with other terminal devices (for example, when feeding back CQI and PMI in consideration of inter-user interference).

Further, in the base station device and the terminal device according to the present embodiment, when the terminal device feeds back an RI larger than a predetermined value, the feedback information is equivalent to (or equal to or less than) the case where the RI smaller than the predetermined value is fed back. In order to achieve the quantity, the value of M can limit the feedback of the first PMI and the second PMI.

The base station device can set the value of M and the value of L when the terminal device feeds back an RI larger than a predetermined value to the terminal device. At this time, the value of L set by the base station device with respect to the terminal device is preferably not more than or equal to the value of L set when the terminal device feeds back RI of a predetermined value or less.

Further, the terminal device can be set in advance with a value of L according to the value of M from the base station device. At this time, when feeding back an RI larger than a predetermined value, the terminal device can set a value (as L) different from L according to the value of M set by the base station device. As the value set by the terminal device, it is preferable to set a value smaller than L set by the base station device as L.

The base station device and the terminal device can limit the number of candidates to be considered as the second PMI when M larger than a predetermined value is set and when the terminal device feeds back an RI larger than a predetermined value. .. For example, candidates for the phase factor assistance is feedback PMI21 is determined by the N _PSK the base station apparatus notifies. The base station apparatus as a candidate for _{N PSK,} can be considered {2,4,8}. Depending on the value of N _PSK , the phase difference (angle difference) between the candidate values of the phase coefficient fed back by the terminal device changes, and 360 ° / N _PSK becomes the phase difference. The base station apparatus, the value of N _PSK, can be set in the terminal apparatus, base station apparatus, when a predetermined value is set greater than M to the terminal device, the value of N _PSK than a predetermined value It can be made smaller. Similarly, the terminal apparatus, if the predetermined value is greater than M is set, it is possible to set the value of N _PSK, the value set smaller value than the base station apparatus as N _PSK.

The base station apparatus can define at least a table showing the relationship between M, R, and RI. That is, by referring to the table, the terminal device can acquire an RI that the terminal device can feed back by M or R notified from the base station device. Further, the terminal device can acquire M and R to be set when calculating the CSI according to the feedback RI. The base station apparatus can define a table showing the relationship between M and R for each RI (number of ranks, number of layers). The base station apparatus can define at least a plurality of tables showing the relationship between M, R, and RI. The terminal device can set the table to be referred to from the base station device. The terminal device identifies the table to be referred to by the signaling of the upper layer notified from the base station device, the signaling of the physical layer (DCI or CSI trigger), or the scramble ID used when demodulating the downlink control signal. be able to.

In addition, the terminal device can be notified of information indicating an assumed base from the base station device. In this case, the terminal device can calculate W1 and W2 based on the notified basis. In particular, when the base station device requests CSI feedback in consideration of inter-user interference from other terminal devices, the terminal device can provide CSI feedback based on the set basis. The terminal device chooses whether to use a preset basis or to set the rules based on channel estimates estimated based on CSI-RS, based on whether inter-user interference is taken into account. Can be done.

When the terminal device provides CSI feedback using a preset base during FD compression, the terminal device may notify the base station device of information indicating the base. In addition, the terminal device may notify the base station device of the base by using a predetermined signature. The signature defined here is, for example, a predetermined bit string described in a predetermined bit field of control information.

The base station device can be set in the terminal device to assume only a predetermined number of ranks for FD compression. In this case, the terminal device can usually describe different information in the bit field indicating RI when feeding back the CSI that performs FD compression. Here, the other information can be information indicating a regulation assumed by the terminal device. Further, the terminal device can notify the base station device that the terminal device assumes FD compression by describing a predetermined bit sequence in the bit field indicating RI.

The base station device can preset a combination of basis vectors to be considered when calculating the CSI for the terminal device. When calculating the first PMI and the second PMI, the terminal device searches for a suitable combination as CSI feedback from the candidate vectors and coefficients, and feeds back the index to the base station device. Therefore, the larger the number of candidate vectors and coefficients, the higher the accuracy of the CSI that can be fed back, but the enormous amount of calculation required for the terminal device. Therefore, the base station apparatus according to the present embodiment has any of a combination of a vector (first PMI), a coefficient (second PMI), and a basis to be considered when calculating the CSI for the terminal apparatus in advance. Alternatively, a plurality of combinations (subsets) thereof can be set in advance. The terminal device can notify the base station device of an index indicating the combination that can most accurately notify the propagation path information between the terminal device and the base station device among the preset combinations. By setting in this way, the terminal device can avoid an increase in the amount of calculation due to the calculation of CSI. Further, when the number of subsets is K0, the amount of information related to feedback can also be controlled by controlling K0.

In the terminal device according to the present embodiment, the value of RI to be fed back can be limited according to the value of K0 set by the base station device. For example, when the value of K0 set by the base station device is larger than a predetermined value, the terminal device can feed back an RI of a predetermined value or less. Further, when the feedback RI is larger than a predetermined value, the terminal device can set K0 to a value different from K0 notified by the base station device. That is, the terminal device considers a number of subsets when the feedback RI is greater than a predetermined value than when the feedback RI is less than or equal to a predetermined value.

Further, the base station apparatus according to the present embodiment can set K0 that can be fed back for each RI. That is, a table showing the relationship between RI and K0 can be defined. The terminal device can recognize the RI that can be fed back by the terminal device by referring to K0 notified from the base station device and the table concerned. In addition, the terminal device can acquire K0 from the table based on the feedback RI.

Further, in the terminal device according to the present embodiment, a combination of one subset can be set. That is, the terminal device is set with K0 subsets set by the combination of the plurality of vectors, and the terminal device selects an appropriate subset from the K0 subsets. Here, the base station apparatus can notify in advance which of the plurality of vectors constituting the subset itself does not need to be considered by the terminal apparatus. Similarly, the base station apparatus can notify in advance a subset of the K0 subsets that the terminal apparatus does not need to consider. The base station device can associate the limits of the plurality of vectors that make up the subset itself, and the limits of the subset itself, with the RI of the terminal device. That is, the base station device gives the terminal device a vector or the subset itself that constitutes a subset that the terminal device does not have to consider when the terminal device feeds back an RI larger than a predetermined value to the terminal device. You can notify.

The terminal device can feed back any one of the subsets for each layer when feeding back an RI larger than a predetermined value. Further, the terminal device does not select a subset for each layer, but feeds back one subset to the base station device, and the base station device recognizes that the subset can be applied in common to all layers. , Precoding can be done. When feeding back an RI larger than a predetermined value, the terminal device does not need to feed back an index indicating a subset to layers having a predetermined value or more.

When the terminal device feeds back an RI larger than a predetermined value, the terminal device may feed back only the number of considered basis vectors, not an index indicating the basis vector selected during FD compression. it can. In this case, the base station device and the terminal device can determine in advance the order of the vectors considered by the terminal device among the N3 base vectors. Therefore, the terminal device feeds back only the number of vectors considered to the base station device, so that the base station device can correctly demodulate the FD-compressed information.

Further, when feeding back an RI larger than a predetermined value, the terminal device can feed back information indicating another layer as an index indicating a subset for layers having a predetermined value or more. In this case, the base station apparatus can precode the layer having a predetermined value or more based on the information of the subset fed back to the layer indicated by the information indicated by the other layers.

Further, the base station apparatus can preset a vector or a coefficient that does not need to be considered among the candidates of the first PMI and the second PMI for the terminal apparatus. When the base station device includes the first PMI and the second PMI candidates previously restricted by the base station device among the vectors and coefficients constituting the subset set for the terminal device, the terminal The device can calculate the CSI even in the subset notified by the base station device without considering the relevant vector or coefficient. On the other hand, if the terminal device includes a previously restricted vector or coefficient in the subset notified by the base station device, the terminal device shall calculate the CSI in consideration of the restricted vector or coefficient. Can be done.

The terminal device sets the Vectors and coefficients that do not need to be considered among the candidates of the first PMI and the second PMI in advance, and the CodebookSubsetRetrytion (first).
(Limitation) and Subset Selection (second limitation) for FD compression are not considered to be set at the same time. When the first limit and the second limit are set at the same time, the terminal device can give priority to any one and set one.

Also, assuming that signals are transmitted from different transmission points to the terminal device, FD
It is not desirable that the number of units, the number of subsets, and their combinations be common among layers. This is because different transmission points mean that the delay profiles of the propagation paths are different. Therefore, the FD unit size, the number of subsets, and their combinations can be made common among layers because the CSI-RSs referred to when calculating the CSI are guaranteed by the QCL for at least the reception parameters. Will be the case.

If the base station device may transmit a CSI-RS whose QCL is not guaranteed, the CSI-RS configuration information should include at least one of the FD unit size, the number of subsets, and a combination thereof. Can be done. By controlling in this way, the terminal device can correctly estimate the CSI for the channel to which the CSI-RS referred to when calculating the CSI has propagated.

According to the method described above, it is possible to avoid an increase in the amount of feedback information generated when the terminal device feeds back an RI larger than a predetermined value, and the frequency utilization efficiency is improved.
[2. Common to all embodiments]

The program that operates in the apparatus according to the present invention may be a program that controls the Central Processing Unit (CPU) or the like to operate the computer so as to realize the functions of the embodiments according to the present invention. The program or the information handled by the program is temporarily stored in a volatile memory such as Random Access Memory (RAM), a non-volatile memory such as a flash memory, a Hard Disk Drive (HDD), or other storage device system.

The program for realizing the function of the embodiment according to the present invention may be recorded on a computer-readable recording medium. It may be realized by loading the program recorded on this recording medium into a computer system and executing it. The "computer system" as used herein is a computer system built into a device, and includes hardware such as an operating system and peripheral devices. Further, the "computer-readable recording medium" is a semiconductor recording medium, an optical recording medium, a magnetic recording medium, a medium that dynamically holds a program for a short time, or another recording medium that can be read by a computer. Is also good.

Also, each functional block, or feature, of the device used in the embodiments described above may be implemented or implemented in an electrical circuit, such as an integrated circuit or a plurality of integrated circuits. Electrical circuits designed to perform the functions described herein are general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or others. Programmable logic devices, discrete gate or transistor logic, discrete hardware components, or a combination thereof may be included. The general purpose processor may be a microprocessor, a conventional processor, a controller, a microcontroller, or a state machine. The electric circuit described above may be composed of a digital circuit or an analog circuit. In addition, when an integrated circuit technology that replaces the current integrated circuit appears due to advances in semiconductor technology, one or more aspects of the present invention can also use a new integrated circuit according to the technology.

The invention of the present application is not limited to the above-described embodiment. Although an example of the device has been described in the embodiment, the present invention is not limited to this, and the present invention is not limited to this, and the stationary or non-movable electronic device installed indoors or outdoors, for example, an AV device, a kitchen device, and the like. It can be applied to terminal devices or communication devices such as cleaning / washing equipment, air conditioning equipment, office equipment, vending machines, and other living equipment.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within a range not deviating from the gist of the present invention are also included. Further, the present invention can be variously modified within the scope of the claims, and the technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is done. In addition, the elements described in each of the above-described embodiments include a configuration in which elements having the same effect are replaced with each other.

The present invention is suitable for use in base station equipment, terminal equipment and communication methods.

1A, 3A, 5A, 7A, 9A Base station device 2A, 4A, 6A Terminal device 101 Upper layer processing unit 102 Control unit 103 Transmission unit 104 Reception unit 105 Transmission / reception antenna 106 Measurement unit 1011 Wireless resource control unit 1012 Scheduling unit 1031 Coding Unit 1032 Modulation unit 1033 Downlink reference signal generation unit 1034 Multiplexing unit 1035 Wireless transmitting unit 1041 Wireless receiving unit 1042 Multiplexing unit 1043 Demodizing unit 1044 Decoding unit 201 Upper layer processing unit 202 Control unit 203 Transmitting unit 204 Receiver 205 Measuring unit 206 Transmission / reception antenna 2011 Wireless resource control unit 2012 Scheduling information interpretation unit 2031 Coding unit 2032 Modulation unit 2033 Uplink reference signal generation unit 2034 Multiplexing unit 2035 Wireless transmitting unit 2041 Wireless receiving unit 2042 Multiplexing unit 2043 Signal detection unit

Claims (4)

A base station device that communicates with a terminal device
A transmitter that transmits at least one NZP CSI-RS,
A receiver that receives a signal containing at least one CSI.
The CSI includes at least RI and PMI
The CSI further contains information indicating the basis for applying the PMI to a matrix arranged in a predetermined dimension.
The transmitter signals a value indicating the number of PMIs arranged in the predetermined dimension.
A base station device that sets information associated with the number of PMIs arranged in the predetermined dimension, the number of bases, and the RI in the terminal device. The base station device according to claim 1, wherein when the terminal device notifies an RI larger than a predetermined value, the terminal device signals information indicating the number of bases set by the terminal device. There is a terminal device that communicates with the base station device,
A receiver that receives at least one NZP CSI-RS,
A transmitter that transmits a signal containing at least one CSI.
The CSI includes at least RI and PMI
The CSI further contains information indicating the basis for applying the PMI to a matrix arranged in a predetermined dimension.
The receiving unit acquires a value indicating the number of the PMIs arranged in the predetermined dimension, and obtains a value indicating the number of the PMIs.
When the value indicating the number of the PMIs arranged in the predetermined dimension exceeds the first predetermined value and the value of the RI exceeds the second predetermined value, the number of vectors indicated by the PMI is the third. A terminal device that is set to a predetermined value. It is a communication method of the base station device that communicates with the terminal device.
With the step of transmitting at least one NZP CSI-RS,
With a step of receiving a signal containing at least one CSI,
The CSI includes at least RI and PMI
The CSI further contains information indicating the basis for applying the PMI to a matrix arranged in a predetermined dimension.
Further, a step of signaling a value indicating the number of the PMIs arranged in the predetermined dimension,
A communication method comprising a step of setting information associated with the number of PMIs arranged in the predetermined dimension, the number of bases, and the RI in the terminal device.

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