WO2021145409A1 - Communication device and communication method - Google Patents

Abstract

The present invention is provided with a transmission/reception unit for receiving an uplink reference signal and transmitting multi-layer signals, and a channel estimation unit for estimating the estimated channel value of a downlink channel from the uplink reference signal. The uplink reference signal is transmitted from a communication partner using a plurality of antennas, and the phases and amplitudes of the multi-layer signals are controlled using the estimated channel value, each of the multi-layer signals being transmitted in association with each of the plurality of antennas.

Description

Communication device and communication method

The present invention relates to a communication device and a communication method.
The present application claims priority with respect to Japanese Patent Application No. 2020-006001 filed in Japan on January 17, 2020, the contents of which are incorporated herein by reference.

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), which is an international standardization organization, has issued a vision recommendation regarding the standard method (International mobile telecommunication-2020 and beyond: IMT-2020) of 5G systems. Reported (see Non-Patent Document 1).

Wireless communication will become more and more important in the future, and the number of communication devices is expected to increase further. Security can be an issue at this time. Security is one of the most important technologies in communication systems. In general, for security, secure communication by encryption at a layer higher than the physical layer is often used. However, since wireless communication is transmitted over a wide area, an eavesdropper may be able to receive unencrypted control information or the like. There is physical layer security as a technique for secure communication in such a physical layer. As a physical layer security technique, for example, there is a technique of adding null artificial noise to a transmission signal and transmitting it to a legitimate user. Artificial noise is a technology that enables secure communication using a wireless channel between the transmitting side and a legitimate user as a key. Non-Patent Document 2 describes a physical layer security technique using artificial noise.

Since the method described in Non-Patent Document 2 uses a wireless channel as a key, a downlink channel estimate is required on the transmitting side. When an error occurs in the channel estimate, if transmission control is performed using the channel estimate including the error, the legitimate user may not be able to correctly receive the desired signal.

One aspect of the present invention has been made in view of such circumstances, and an object of the present invention is to provide a communication device and a communication method capable of safely communicating even when the channel estimated value includes an error. To provide.

The configuration of the communication device and the communication method according to one aspect of the present invention in order to solve the above-mentioned problems is as follows.

The communication device according to one aspect of the present invention includes a transmission / reception unit that receives an uplink reference signal and transmits signals of a plurality of layers, and a channel estimation unit that estimates a downlink channel channel estimation value from the uplink reference signal. , The uplink reference signal is transmitted from a communication partner using a plurality of antennas, and the signals of the plurality of layers are phase-controlled and amplitude-controlled using the channel estimates, and the signals of the plurality of layers are subjected to phase control and amplitude control. Each is associated with and transmitted to each of the plurality of antennas.

Further, in the communication device according to one aspect of the present invention, the transmission / reception unit transmits a reference signal (CSI-RS) for measuring channel state information (CSI), and the number of resources of the CSI-RS is plurality. , Each of the plurality of CSI-RS resources is for measuring CSI for different ranks, each of the plurality of CSI-RS resources is set with a mapping to one resource element, and the resource element is , One Orthogonal Frequency Division Multiplexing (OFDM) symbol in a slot and one subcarrier in a resource block.

Further, in the communication device according to one aspect of the present invention, the channel quality index (CQI) in each of the plurality of CSI-RS resources is received.

Further, in the communication device according to one aspect of the present invention, the CSI-RS resource index indicating one of the plurality of CSI-RS resources and the channel quality index (CQI) measured by the CSI-RS resource are received. ..

Further, the communication device according to one aspect of the present invention uses a plurality of antennas to transmit an uplink reference signal and to receive a plurality of layer signals, and to detect a desired signal from the received signals of the plurality of layers. Each of the plurality of layers and each of the plurality of antennas are associated with each other.

Further, in the communication device according to one aspect of the present invention, each of the signals of the plurality of layers is obtained based on one of the plurality of antennas.

Further, in the communication device according to one aspect of the present invention, the transmission / reception unit receives a reference signal (CSI-RS) for measuring channel state information (CSI), and the number of resources of the CSI-RS is plurality. , Each of the plurality of CSI-RS resources is for measuring CSI for different ranks, each of the plurality of CSI-RS resources is set with a mapping to one resource element, and the resource element is , One Orthogonal Frequency Division Multiplexing (OFDM) symbol in a slot and one subcarrier in a resource block.

Further, in the communication device according to one aspect of the present invention, the channel quality index (CQI) in each of the plurality of CSI-RS resources is measured, and the CSI-RS resource and the CQI are reported in association with each other.

Further, in the communication device according to one aspect of the present invention, one is selected from the plurality of CSI-RS resources, and the selected CSI-RS resource index and the channel quality index (CQI) measured by the CSI-RS resource are used. Report.

Further, the communication method according to one aspect of the present invention includes a step of receiving an uplink reference signal and transmitting a signal of a plurality of layers, and a step of estimating a downlink channel estimated value from the uplink reference signal. The uplink reference signal is transmitted from a communication partner using a plurality of antennas, the signals of the plurality of layers are phase-controlled and amplitude-controlled using the channel estimates, and each of the signals of the plurality of layers is controlled. Is transmitted in association with each of the plurality of antennas.

According to one aspect of the present invention, since diversity synthesis is performed on the receiving side, secure communication is possible even when the channel estimated value contains an error.

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 configuration example of the base station apparatus and the terminal apparatus 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, gNodeB, transmission point, transmission / reception point, transmission panel, access point, sub-array, etc. It includes a communication device) and a terminal device (terminal, mobile terminal, receiving point, receiving terminal, receiving device, receiving antenna group, receiving antenna port group, UE, receiving point, receiving panel, station, sub-array, communication device). A base station device connected to a terminal device (establishing a wireless link) is called a serving cell. In the following embodiments, the term "communication device" refers to a base station device or a terminal device.

The base station device and the terminal device in this embodiment can communicate in a frequency band that requires a license (license band) and / or a frequency band that does not require a license (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".

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, 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 includes ACK (a positive acknowledgment) or NACK (a negative acknowledgement) (ACK / NACK) for downlink data (downlink transport block, Downlink-Shared Channel: DL-SCH). ACK / NACK for downlink data is also referred to as HARQ-ACK or HARQ feedback.

In addition, the uplink control information includes channel state information (Channel State Information: CSI) for the downlink. In addition, the uplink control information includes a scheduling request (Scheduling Request: SR) used for requesting a resource of the uplink shared channel (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, reference signal) resource index indicating suitable CSI-RS resource Measured by CRI (CSI-RS Resource Indicator), CSI-RS or SS (Synchronization Signal; synchronization signal) RSRP (Reference Signal Received Power) etc. are 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. can. The CQI value can be an index (CQIIndex) 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 can be determined in advance by the system. The rank index and the pre-recording matrix index can be an index determined by the spatial multiples and the 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.

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 send RRC messages. The RRC message is information / signal processed in the radio resource control (RRC) layer. In addition, PUSCH is used to transmit MAC CE (Control Element). Here, MAC CE is information / signal processed (transmitted) in the medium access control (MAC) layer.

For example, the 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 send a random access preamble.

Also, in uplink wireless communication, an uplink reference signal (Uplink Reference Signal: ULRS) 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 related to the transmission of PUSCH or PUCCH. For example, base station apparatus 1A uses DMRS to perform PUSCH or PUCCH propagation path correction. 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)
-PDCCH (Physical Downlink Control Channel)
・ EPDCCH (Enhanced Physical Downlink Control Channel)
・ PDSCH (Physical Downlink Shared Channel)

PBCH is used to notify the master information block (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, code word) received by 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 an ACK indicating that the data was correctly received, an NACK indicating that the data was not received correctly, and a 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 downlink includes information on PDSCH resource allocation, information on MCS (Modulation and Coding Scheme) for PDSCH, and downlink control information such as TPC command for PUCCH. Here, the DCI format for the downlink is also referred to as a downlink grant (or downlink assignment).

Further, for example, as the DCI format for the uplink, the DCI format 0 used for scheduling one PUSCH (transmission of one uplink transport block) in one cell 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 a TPC command 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 mode setting (CSI report mode) for periodically reporting channel status information.

For example, the channel state information report can be used for setting 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, the channel state information report can be used to set an uplink resource for reporting semi-persistent CSI. The channel status information report can be used for setting a mode (CSI report mode) for semi-permanently reporting channel status information. The semi-permanent CSI report is a periodic CSI report during the period of activation and deactivation by 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. Further, when the PUSCH resource is scheduled by using the uplink grant, the terminal device transmits the uplink data and / or the uplink control information by the scheduled PUSCH.

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.

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 information.

Also, PDSCH is used to send 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. In addition, PDSCH is used to transmit MAC CE.

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

Also, PDSCH can 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 reporting can be used to indicate an uplink resource that periodically reports channel state information (PeriodicCSI). The channel status information report can be used for mode setting (CSI report mode) for periodically reporting channel status information.

There are two types of downlink channel status information reporting: wideband CSI (for example, Wideband CSI) and narrowband CSI (for example, 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.

In downlink wireless communication, a synchronization signal (Synchronization signal: SS) and a downlink reference signal (Downlink Reference Signal: DLRS) 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 signal includes a primary synchronization signal (PrimarySynchronizationSignal: PSS) and a secondary synchronization signal (SecondarySynchronizationSignal: SSS).

The synchronization signal is used by the terminal device to synchronize the frequency domain and the time domain of the downlink. In addition, the synchronization signal is used to measure the 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 signal includes DMRS (Demodulation Reference Signal; 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.

DMRS is transmitted in the subframes and bands used to transmit DMRS-related PDSCH / PBCH / PDCCH / EPDCCH, and is used to demodulate DMRS-related PDSCH / PBCH / PDCCH / EPDCCH.

Here, the downlink physical channel and the downlink physical signal are collectively referred to as a downlink physical signal. Further, 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.

Also, BCH, UL-SCH and DL-SCH are transport channels. The channel used in the MAC layer is called a transport channel. Further, the unit of the transport channel used in the MAC layer is also referred to as a transport block (Transport Block: TB) or a 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 code word, and coding processing or the like is performed for each code word.

In addition, the base station device can integrate and communicate with a plurality of component carriers (CC; Component Carrier) for wider band transmission with respect to the terminal device that supports carrier aggregation (CA). .. 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; Dual Connectivity), a master cell group (MCG; Master Cell Group) and a secondary cell group (SCG; Secondary Cell Group) 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. Also, minislots are composed 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).

Also, a resource block is defined by 12 consecutive subcarriers. The resource element is defined by an index in the frequency domain (for example, a subcarrier index) and an index in the time domain (for example, an 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.

Also, multiple subcarrier intervals (Subcarrier spacing: SCS) are supported. For example, the SCS is 15/30/60/120/240/480 kHz.

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 a transmission / reception unit (transmission / reception step) 100, an upper layer processing unit (upper layer processing step) 101, a control unit (control step) 102, and a transmission / reception antenna 105. The transmission / reception unit 100 includes a transmission unit (transmission step) 103, a reception unit (reception step) 104, and a measurement 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 (wireless 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 integration protocol (Packet Data Convergence Protocol: PDCP) layer, a radio link control (Radio Link Control: RLC) layer, and a radio resource control (Radio). ResourceControl: RRC) Layer processing is performed. 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 (UE capability) of the terminal device from the terminal device. In other words, the terminal device transmits its function to the base station device by a signal of the upper layer.

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 a predetermined function is supported may be notified 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 slot to which the physical channels (PDSCH and PUSCH) are allocated, 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 sets the coding bits input from the coding unit 1031 to BPSK (Binary Phase Shift Keying), QPSK (quadrature Phase Shift Keying), 16QAM (quadrature amplification modulation), 64QAM, 256QAM, or the like. 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 transmission unit 1035 generates an OFDM symbol by performing an inverse fast Fourier transformation (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 to 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 receiving unit 104 separates, demodulates, and decodes the received signal received from the terminal device 2A via the transmitting / receiving 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 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 wireless receiver 1041 removes the 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. 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 multiple 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 transformation (Inverse Discrete Fourier Transform: IDFT) on PUSCH, acquires modulation symbols, and for each of the modulation symbols of PUCCH and PUSCH, BPSK, QPSK, 16QAM, 64QAM, 256QAM, etc. in advance. 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. Decoding 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 a transmission / reception unit (transmission / reception step) 200, an upper layer processing unit (upper layer processing step) 201, a control unit (control step) 202, and a transmission / reception antenna 206. Further, the transmission / reception unit 200 includes a transmission unit (transmission step) 203, a reception unit (reception step) 204, and a measurement unit (measurement step) 205. 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 (wireless transmission step) 2035. Further, the receiving unit 204 includes a wireless receiving unit (radio receiving step) 2041, a multiple separation unit (multiple 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, a packet data integration protocol (PacketData Convergence Protocol: PDCP) layer, a wireless link control (RadioLink Control: RLC) layer, and a wireless resource control (RadioLink Control: RLC) layer. RadioResourceControl: 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 wireless 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 transmitting / receiving 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. do.

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 wireless receiver 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 separation unit 2042 separates the extracted signal into PHICH, PDCCH, EPDCCH, PDSCH, and downlink reference signal, 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 estimated value of the desired signal to the signal detection unit 2043.

The signal detection unit 2043 demodulates and decodes using the PDSCH and the channel estimated value, and outputs the data to the upper layer processing unit 201.

The measurement 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 of 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 generation unit 2033 is 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. Based on the notified cyclic shift, the value of the parameter for the generation of the DMRS sequence, etc., a series obtained by a predetermined rule (expression) is generated.

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 transmission unit 2035 performs inverse fast Fourier transform (IFFT) on the multiplexed signal, performs OFDM modulation, generates an OFDMA symbol, adds CP to the generated OFDMA symbol, and bases it. Generates a band digital signal, converts the baseband digital signal to an analog signal, removes excess frequency components, converts it to a carrier frequency by up-conversion, amplifies the power, outputs it to the transmit / receive antenna 206, and transmits it. ..

Note that the terminal device is not limited to the OFDMA system, and can perform modulation of the SC-FDMA (DFT-sprad-OFDMA) system.

Especially in a wireless communication system, it is one of the most important things to communicate safely with a communication partner without leaking information to anyone other than a legitimate user (legitimate terminal device). In order to maintain secure communication, encryption by an upper layer is common. In order to further enhance safety, it is desirable to take security measures at the physical layer as well.

In wireless communication, since the transmitted signal reaches a wide range, it is possible for an eavesdropper (non-genuine user, non-genuine terminal device) to receive the wireless signal. If unencrypted control information is leaked, the probability that the eavesdropper can demodulate / decrypt it increases. Therefore, in the physical layer, secure communication is possible by making demodulation / decoding difficult by an eavesdropper.

In addition, the base station device can transmit the desired signal with a random phase and amplitude from each of the plurality of transmitting antennas so that the legitimate user can correctly receive the desired signal and the non-regular user cannot correctly receive the desired signal. Can be done (also called random phase method). Further, if the amplitude is obtained so that the transmission power becomes small, safe communication becomes possible while suppressing the transmission power. The random phase method requires that the sender knows the channel to and from the legitimate user. In the present embodiment, secure communication from the base station device to the regular terminal device will be described, but one aspect of the present invention is not limited to this. For example, one aspect of the present invention is also included in the case of secure communication from a legitimate terminal device to a base station device.

The above-mentioned random phase method estimates the channel in order to know the channel in the base station apparatus. Since the channel estimates include errors, the legitimate terminal device may not be able to receive the desired signal accurately. Therefore, on the receiving side, the desired signal is extracted by diversity synthesis using a plurality of receiving antennas. To increase safety, the legitimate terminal device estimates by blind estimation without training signals.

In addition, since the legitimate terminal device is provided with a plurality of receiving antennas, high-speed transmission with high safety is performed if the transmitting side transmits the signals of a plurality of layers (streams) by spatially multiplexing and transmitting by the MIMO (Multiple Input Multiple Output) method. Is possible.

The details of the random phase method will be described. _{The modulated signal bk} (n) of the kth subcarrier of the tth transmitting antenna can be expressed by Eq. (1).

However, θ _{t and k} represent the phases randomly set by the base station apparatus. Further, a t _(k) is the amplitude of the t transmit antennas, the modulation signal of the k subcarrier. Further, a t _(k) is allowed to receive the desired signal correctly, and is determined so as to suppress the transmission power. _{Incidentally, a} t (k) is a real number, may take a negative value. _{Further, it is desirable that the desired signal dr} (k) of the r-th layer and the k-th subcarrier to be correctly received by the regular terminal device is as shown in the equation (2).

However, _NT is the number of transmitting antennas, and H _{q, t} (k) is the channel between the qth receiving antenna and the t transmitting antenna. That is, the desired signal of the rth layer is transmitted so as to be received by the qth receiving antenna. At this _{time, a} t (k) is obtained as equation (3).

However, H ^ _{q, t} (k) represents the channel estimate _{of H q, t (k).} The superscript T represents the transposed matrix, Re (x) represents the real part of the complex number x, and Im (x) represents the imaginary part of the complex number x.

If the channel estimate contains an error, the legitimate terminal may not be able to receive the desired signal correctly. Therefore, the regular terminal device obtains a desired signal by diversity synthesis. The diversity composite weight can be obtained from the training signal or the reference signal, but it is obtained by a blind algorithm that does not use the training signal or the reference signal in order to improve safety. When the received signal of the kth subcarrier and the iOFDM symbol in the regular terminal device is _{Yk (i), the desired signal d ^ r} (k) of the rth layer and the kth subcarrier obtained by the regular terminal device is the first. the equation (8) using a diversity combining weights W _r of r layer.

However, the superscript H represents the complex conjugate transposed matrix, and λ is the forgetting coefficient. Also, δ is a very small positive number. The C _r is N _{R-dimensional} vector, elements for each layer to obtain different. For example, when receiving a desired signal of the r layer in the q receive antennas, C _r in the q element 1, other elements are zero.

The base station equipment needs to know the downlink channel. In this embodiment, the channel reciprocity of TDD (Time Division Duplex) is assumed, and the downlink channel is estimated using the uplink signal (for example, SRS, uplink DMRS). In the case of multi-layer transmission, transmission is performed from a plurality of transmitting antennas. For example, as shown in FIG. 4, the base station apparatus 401 is provided with _{N T} antennas 402-1 ~ _{402-N T,} normal terminal device 403 is provided with _{N R} antennas 404-1 ~ _{404-N R} And. For example, the legitimate terminal device 403 _{transmits SRS from the N R} antenna port, and the base station device 401 _{receives SRS with NT} antennas to estimate the downlink channel. At this time, the base station apparatus 401 can transmit spatially multiplexed signals up to N _R layer. As described above, the base station apparatus 401 uses the channel estimates to transmit the desired signal so that the signal of each layer is received by the receiving antenna of the regular terminal apparatus 403. In order for the legitimate terminal device 403 to correctly receive the desired signal, the channel must not change significantly. Therefore, it is desirable that the regular terminal device 403 receives the desired signal by using the antenna (or the antenna at the same position) used for transmitting the SRS. Further, since the regular terminal device 403 obtains the diversity composite weight for each receiving antenna and obtains the desired signal of the corresponding layer, it is necessary to associate each layer transmitted by the base station device 401 with the receiving antenna of the regular terminal device 403. .. Here the regular terminal device 403 antenna port number of SRS (or DMRS) and 1 ~ _{N R} using. For example, the layer 1 is associated with the SRS antenna port 1, the layer 2 is associated with the SRS antenna port 2, and so on, and the layer index and the SRS antenna port number are associated with each other on a one-to-one basis. At this time, the regular terminal device receives the layer 1 signal at the same antenna as the SRS antenna port 1, and receives the layer 2 signal at the SRS antenna port 2. Further, when the base station apparatus 401 transmits a signal of L (<N _R) layer, it is also possible to select a good channel state receiving antenna. At this time, the base station apparatus 401 instructs the regular terminal apparatus 403 of the correspondence between the layer index and the SRS antenna port number by the control information. Further, the base station apparatus 401 can indicate the antenna to be received by each layer as QCL (Quantum Collaboration) information. For example, when SRS antenna port number 1 is set as QCL information for layer 1, the regular terminal device 403 receives the layer 1 signal with an antenna having the same channel as when it is received at SRS antenna port number 1. Means you have to.

In the present embodiment, since the base station device estimates the downlink channel, the precoding, rank (number of layers), and MCS suitable for the regular terminal device can be determined using the downlink channel estimated value. On the other hand, if there is a deterioration factor such as cell-to-cell interference that cannot be estimated by the base station device, it is desirable to have the regular terminal device report the CSI. The base station equipment transmits CSI-RS, and the regular terminal equipment obtains and reports a suitable rank index and channel quality index from CSI-RS. In the present embodiment, since the regular terminal device estimates the diversity composite weight by the blind algorithm, the channel estimation using CSI-RS is not performed. Therefore, CSI-RS can measure CSI with one resource element regardless of the number of ranks. In this case, even if a plurality of CSI-RS antenna ports are set in the regular terminal device, the CSI-RS resource may refer to the resource element of one port. For example, the regular terminal device refers to the resource element of the CSI-RS antenna port 1 when the number of ranks is 1, and refers to the resource element of the CSI-RS antenna port 2 when the number of ranks is 2. Note that a maximum of several resource elements are required for rank adaptation. For example, in the case of a maximum of 4 ranks, 4 resource elements are required: a resource element for rank 1, a resource element for rank 2, a resource element for rank 3, and a resource element for rank 4. .. In the resource element for the rank number r, r CSI-RSs are transmitted as CSI-RS. The r CSI-RSs are associated with the r CSI-RS antenna port numbers. For example, r CSI-RSs are the same as CSI-RSs transmitted by CSI-RS antenna port numbers 1 to r. The legitimate receiver measures the CSI using the blindly estimated quality of the CSI-RS. At this time, the regular terminal device can measure the CSI at each resource element and report a suitable rank number, CQI, or RSRP (Reference Signal Received Power) to the base station device. The legitimate terminal device can report a suitable resource index instead of a suitable number of ranks. The regular terminal device can report CQI and RSRP for one or more ranks. The resource element for each rank number can be a different CSI-RS resource. The CSI-RS resource is set by associating the CSI-RS resource ID (identifier) with the resource element to which the CSI-RS is mapped. The resource element to which the CSI-RS is mapped is indicated by the OFDM symbol in the slot in which the CSI-RS is transmitted and the subcarrier in the resource block. Further, the CSI-RS resource used for the rank measurement may be included in one CSI-RS resource set. For example, the maximum number of ranks to be reported may be the number of CSI-RS resources set in the CSI-RS resource set. Further, since the base station device transmits the CSI-RS based on the downlink channel estimated value as well as the desired signal, it is necessary to indicate the receiving antenna of the legitimate terminal device corresponding to the CSI-RS antenna port. For example, in the legitimate terminal device, each of the CSI-RS antenna ports 1 to R and each of the SRS antenna ports 1 to R are associated with the resource element having the rank number R. Further, the base station apparatus can be set by associating the CSI-RS antenna port and the SRS antenna port as a QCL relationship.

Note that the frequency band used by the communication device (base station device, terminal device) according to the present embodiment is not limited to the license band and unlicensed band described so far. The frequency band targeted by this embodiment is not actually used for the purpose of preventing interference between frequencies, although the use permission for a specific service is given by the country or region. Frequency bands called white bands (for example, frequency bands assigned for television broadcasting but not used in some regions) and, although previously exclusively assigned to specific operators, It also includes a shared frequency band (license sharing band) that is expected to be shared by multiple operators in the future.

The program that operates in the device according to one aspect of the present invention is a program that controls a Central Processing Unit (CPU) or the like to operate a computer so as to realize the functions of the embodiment according to one aspect of the present invention. Is also good. 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 another storage device system.

Note that the program for realizing the function of the embodiment according to one aspect of 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. 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.

Further, each functional block or various features of the device used in the above-described embodiment can be implemented or executed in an electric circuit, for example, 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. 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. In the embodiment, an example of the device has been described, but the present invention is not limited to this, and the present invention is not limited to this, and is a 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.

As described above, the embodiment of the present invention has been described in detail with reference to the drawings, but 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. In addition, one aspect of the present invention can be variously modified within the scope of the claims, and the technical aspects of the present invention are also obtained by appropriately combining the technical means disclosed in the different embodiments. Included in the range. In addition, the elements described in each of the above embodiments include a configuration in which elements having the same effect are replaced with each other.

One aspect of the present invention is suitable for use in communication devices and communication methods.

1A Base station device 2A Terminal device 100 Transmission / reception unit 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 Degrading unit 1044 Decoding unit 200 Transmission / reception unit 201 Upper layer processing unit 202 Control unit 203 Transmission unit 204 Reception unit 205 Measuring unit 206 Transmission / reception antenna 2011 Wireless resource control Part 2012 Scheduling information interpretation part 2031 Coding part 2032 Modulation part 2033 Uplink reference signal generation part 2034 Multiplexing part 2035 Wireless transmitting part 2041 Wireless receiving part 2042 Multiplexing part 2043 Signal detecting part 401 Base station equipment 402-1 to 402-N _T antenna 403 terminal devices 404-1 ~ _{404-N R} antennas

Claims (10)

1. A transmitter / receiver that receives uplink reference signals and transmits signals of multiple layers,
   A channel estimation unit that estimates the channel estimation value of the downlink channel from the uplink reference signal is provided.
   The uplink reference signal is transmitted from a communication partner using a plurality of antennas, and is transmitted.
   The signals of the plurality of layers are phase-controlled and amplitude-controlled using the channel estimates.
   Each of the plurality of layers of signal is transmitted in association with each of the plurality of antennas.
   Communication device.
2. The transmitter / receiver transmits a reference signal (CSI-RS) for channel state information (CSI) measurement.
   The number of resources of the CSI-RS is plural, and each of the plurality of CSI-RS resources is for measuring the CSI for different ranks.
   Each of the plurality of CSI-RS resources is set with a mapping to one resource element.
   The resource element is one orthogonal frequency division multiplexing (OFDM) symbol in the slot and one subcarrier in the resource block.
   The communication device according to claim 1.
3. The communication device according to claim 2, which receives a channel quality index (CQI) in each of the plurality of CSI-RS resources.
4. The communication device according to claim 2, which receives a CSI-RS resource index indicating one of the plurality of CSI-RS resources and a channel quality index (CQI) measured by the CSI-RS resource.
5. A transmitter / receiver that transmits uplink reference signals and receives multiple layer signals using multiple antennas.
   A signal detection unit that detects a desired signal from the received signals of a plurality of layers is provided.
   A communication device in which each of the plurality of layers and each of the plurality of antennas are associated with each other.
6. The communication device according to claim 5, wherein each of the signals of the plurality of layers is obtained based on one of the plurality of antennas.
7. The transmitter / receiver receives a reference signal (CSI-RS) for channel state information (CSI) measurement, and receives the reference signal (CSI-RS).
   The number of resources of the CSI-RS is plural, and each of the plurality of CSI-RS resources is for measuring the CSI for different ranks.
   Each of the plurality of CSI-RS resources is set with a mapping to one resource element.
   The resource element is one orthogonal frequency division multiplexing (OFDM) symbol in the slot and one subcarrier in the resource block.
   The communication device according to claim 5.
8. The channel quality index (CQI) in each of the plurality of CSI-RS resources was measured and
   The communication device according to claim 6, wherein the CSI-RS resource is associated with the CQI and reported.
9. The communication device according to claim 6, wherein one is selected from the plurality of CSI-RS resources, and the selected CSI-RS resource index and the channel quality index (CQI) measured by the CSI-RS resource are reported.
10. The step of receiving the uplink reference signal and transmitting the signal of multiple layers,
    A step of estimating the channel estimate of the downlink channel from the uplink reference signal is provided.
    The uplink reference signal is transmitted from a communication partner using a plurality of antennas, and is transmitted.
    The signals of the plurality of layers are phase-controlled and amplitude-controlled using the channel estimates.
    Each of the plurality of layers of signal is transmitted in association with each of the plurality of antennas.
    Communication method.

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