KR20240071267A - Method and apparatus for MIMO transmission - Google Patents

Abstract

In order to achieve the above object, a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure includes the steps of transmitting a Sounding Reference Signal (SRS) to a base station, and Transmit TPMI (TPMI) indicating a precoding matrix from the base station. Receiving a Precoding Matrix Indicator (RI) indicating a rank value, selecting a precoding matrix based on TPMI and the RI, based on the loss information and precoding matrix of each of a plurality of transmission paths The method includes allocating a gain to each of a plurality of transmission paths and transmitting a Physical Uplink Shared Channel (PUSCH) through the plurality of transmission paths.

Description

Device for multiple antenna transmission and method of operating the device {Method and apparatus for MIMO transmission}

The technical idea of the present disclosure relates to a wireless communication device and a method of operating the same, and more specifically, a wireless communication device that performs multi-antenna transmission by applying an efficient precoding matrix based on the loss information of the transmission path or the frequency of the transmission signal. and a method of operation thereof.

A wireless communication system can employ various techniques to increase throughput. For example, a wireless communication system may employ Multiple-Input and Multiple-Output (MIMO), which increases communication capacity by using multiple antennas. As techniques for increasing transmission volume are adopted, the transmitting side can transmit signals with high complexity, while the receiving side may be required to process signals with high complexity.

The new radio (NR) specification includes a codebook-based transmission mode and a non-codebook-based transmission mode in relation to uplink multiple antenna precoding. In the case of codebook-based transmission mode, the precoder matrix that the terminal can use is determined by the standard. The precoder matrix determined by the standard is independent of the loss information of the terminal's transmission path and is equally applied to the entire frequency range of the transmission signal. In order to increase spectral efficiency, it is required to select a precoding matrix by considering loss information of the terminal's transmission path or the frequency domain of the transmission signal.

The technical idea of the present disclosure is to provide a wireless communication device that performs multi-antenna based transmission and reception by determining a precoding matrix based on the loss information of the transmission path of the terminal or the frequency domain of the transmission signal and a method of operating the same. It is there.

In order to achieve the above object, a method of operating a wireless communication device according to an aspect of the technical idea of the present disclosure includes the steps of transmitting a Sounding Reference Signal (SRS) to a base station, and TPMI (TPMI) indicating a precoding matrix from the base station. Receiving a Transmit Precoding Matrix Indicator (RI) indicating a rank value, selecting a precoding matrix based on TPMI and the RI, and adding information to the loss information and precoding matrix of each of the plurality of transmission paths. It is characterized in that it includes the step of allocating a gain to each of a plurality of transmission paths based on the step of transmitting a PUSCH (Physical Uplink Shared Channel) through the plurality of transmission paths.

In order to achieve the above object, a wireless communication device according to one aspect of the technical idea of the present disclosure transmits a Sounding Reference Signal (SRS) to a base station and transmits a Transmit Precoding Matrix Indicator (TPMI) that indicates a precoding matrix from the base station. ) and a communication circuit that receives an RI (Rank Indicator) indicating a rank value, selects a precoding matrix based on TPMI and RI, calculates a gain allocation matrix based on loss information of each of the plurality of transmission paths, A processor that allocates a gain to each of the plurality of transmission paths based on a gain allocation matrix and a precoding matrix, and transmits a PUSCH (Physical Uplink Shared Channel) to the base station through the plurality of transmission paths to which the gains are assigned. It is characterized by:

In order to achieve the above object, a method of operating a wireless communication device according to an aspect of the technical idea of the present disclosure includes transmitting a Sounding Reference Signal (SRS) to a base station, and transmitting a plurality of Resource Block Groups (RBGs) from the base station. Receiving a Transmit Precoding Matrix Indicator (TPMI) RBG bitmap including information indicating a precoding matrix corresponding to each of the RBG bitmaps, and receiving a different precoding matrix for each of the plurality of RBGs based on the RBG bitmap. It includes transmitting a Physical Uplink Shared Channel (PUSCH) to the base station, wherein each of the plurality of RBGs includes at least one Resource Block (RB).

According to an exemplary embodiment of the present disclosure, a wireless communication device and a method of operating the wireless communication device include, when a wireless communication device transmits a Physical Uplink Shared Channel (PUSCH) in a Multiple-Input and Multiple-Output (MIMO) environment, Spectral efficiency compared to SNR (Signal to Noise Ratio) by applying a precoding matrix that considers the loss information of each of the plurality of transmission paths of the wireless communication device or applying a different precoding matrix depending on the frequency domain of the transmission signal. can increase.

1 illustrates a wireless communication system according to an exemplary embodiment of the present disclosure.
Figure 2 is a block diagram of the base station of Figure 1 according to an exemplary embodiment of the present disclosure.
FIG. 3 is a block diagram of the wireless communication device of FIG. 1 according to an exemplary embodiment of the present disclosure.
FIG. 4 is a detailed block diagram of the communication circuit of FIG. 3 according to an exemplary embodiment of the present disclosure.
Figure 5 is a diagram of signal exchange between a base station and a wireless communication device according to an exemplary embodiment of the present disclosure.
6A and 6B show simulation results according to example embodiments of the present disclosure.
Figure 7 is a flowchart showing a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure.
FIG. 8 is a diagram for explaining a TPMI RBG bitmap according to an exemplary embodiment of the present disclosure.
Figure 9 is a diagram of signal exchange between a base station and a wireless communication device according to an exemplary embodiment of the present disclosure.
Figure 10 shows simulation results according to an exemplary embodiment of the present disclosure.
Figure 11 is a flowchart showing a method of operating a base station according to an exemplary embodiment of the present disclosure.

1 illustrates a wireless communication system according to an exemplary embodiment of the present disclosure.

Referring to FIG. 1, a wireless communication system 10 may include a base station 100 and a wireless communication device 200. The base station 100 is an infrastructure that provides wireless access to the wireless communication device 200. The base station 100 may have coverage defined as a certain geographic area based on the distance over which signals can be transmitted. In addition to the base station, the base station 100 includes an 'access point (AP)', 'eNodeB (eNB)', '5G node (5th generation node)', and 'gNodeB (gNB). )', 'wireless point', or other terms with equivalent technical meaning.

The base station 100 may receive an uplink signal from the wireless communication device 200 based on a multi user (MU)-multiple input multiple output (MIMO) technique. For example, the base station 100 may receive a Physical Uplink Shared Channel (PUSCH) from the wireless communication device 200.

According to the present disclosure, the base station 100 may transmit a control signal indicating scheduling to the wireless communication device 200. The control signal may correspond to an uplink grant signal. The uplink grant may include TPMI, IR, and TPMI RBG bitmaps, which will be described later.

The wireless communication device 200 is a device used by a user and can communicate with the base station 100 through a wireless channel. In addition to a terminal, the wireless communication device 200 includes 'user equipment (UE)', 'mobile station', 'subscriber station', and 'customer premises equipment'. CPE), 'remote terminal' or 'user device' or other terms with equivalent technical meaning.

According to the present disclosure, the wireless communication device 200 may be a wireless communication device set to a codebook-based transmission mode, and the wireless communication device 200 uses at least one antenna port to communicate with the base station 100. An SRS is transmitted, and the base station 100 can receive the SRS and estimate a channel between the transmit antenna port of the wireless communication device 200 and the receive antenna port of the base station 100. The base station 100 may transmit a Transmit Precoding Matrix Indicator (TPMI) and a Rank Indicator (RI) to the wireless communication device 200 based on the channel estimation result. Here, TPMI is information indicating a precoding matrix determined to be appropriate in the rank situation selected by the base station 100, and RI is the rank determined by the base station 100 to be appropriate for wireless communication with the wireless communication device 200, that is, This may be information indicating an appropriate uplink transport layer. The wireless communication device 200 may receive TPMI and RI, select a precoding matrix based on the TPMI and RI, and include the selected precoding matrix and loss information for each of the plurality of transmission paths of the wireless communication device 200. Based on this, a gain can be allocated to each of the plurality of transmission paths.

According to another embodiment of the present disclosure, the wireless communication device 200 transmits an SRS to the base station 100 using at least one antenna port, and the base station 100 receives the SRS to communicate with the wireless communication device 200. The channel between the transmit antenna port of and the receive antenna port of the base station 100 can be estimated. The base station 100 may allocate frequency resources to be used for PUSCH transmission based on the channel estimation result. Here, the frequency resource may include a plurality of RBGs (Resource Block Groups). The base station 100 may generate a TPMI RBG bitmap including information indicating a precoding matrix to be applied to each of the plurality of RBGs and transmit it to the wireless communication device 200. The wireless communication device 200 may transmit a PUSCH to the base station 100 by applying a different precoding matrix to each of the plurality of RBGs based on the TPMI RBG bitmap. PUSCH may be used by the wireless communication device 200 to transmit user data to the base station 100.

Figure 2 is a block diagram of the base station of Figure 1 according to an exemplary embodiment of the present disclosure.

Referring to FIG. 2, the base station 100 of FIG. 1 may include a wireless communication circuit 110, a backhaul communication circuit 120, a memory 130, and a control circuit 140.

The wireless communication circuit 110 may perform functions for transmitting and receiving signals through a wireless channel. According to one embodiment, the wireless communication circuit 110 may perform a conversion function between a baseband signal and a bit string according to the physical layer standard of the system. For example, when transmitting data, the wireless communication circuit 110 may generate modulation symbols by encoding and modulating the transmitted bit string, and when receiving data, the received bit string may be restored by demodulating and decoding the baseband signal. You can. Additionally, the wireless communication circuit 110 may up-convert a baseband signal into a radio frequency (RF) band signal and transmit it through an antenna, or may down-convert an RF band signal received through an antenna into a baseband signal. . To this end, the wireless communication circuit 110 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc.

The wireless communication circuit 110 can transmit and receive signals. For example, the wireless communication circuit 110 may transmit a synchronization signal, reference signal, system information, message, control information, or data. The reference signal may include an uplink sounding reference signal (SRS). For example, the base station 100 may receive an SRS transmitted from a wireless communication device (200 in FIG. 1) through the wireless communication circuit 110. The wireless communication circuit 110 may apply beamforming weights to signals to provide directionality to signals to be transmitted and received. The wireless communication circuit 110 can change the formed beam and transmit signals repeatedly.

The backhaul communication circuit 120 may provide an interface for communicating with other nodes in the network. That is, the backhaul communication circuit 120 converts a bit string transmitted from the base station 100 to another node, for example, another access node, another base station, upper node, core network, etc., into a physical signal, and receives it from the other node. The physical signal can be converted into a bit string.

According to an embodiment of the present disclosure, the base station 100 may allocate frequency resources to be used for receiving PUSCH transmitted by a wireless communication device (200 in FIG. 1), and the allocated frequency resources may include a plurality of RBGs. . The base station 100 may generate a TPMI RBG bitmap including information indicating different precoding matrices to be used for each of a plurality of RBGs and transmit it to the wireless communication device (200 in FIG. 1).

The memory 130 may store data such as basic programs, application programs, and setting information for operation of the base station 100. The memory 130 may be comprised of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. According to an exemplary embodiment of the present disclosure, memory 130 may store channel state information between the wireless communication device (200 in FIG. 1) and base station 100 and/or appropriate precoding matrix information based on frequency band. .

The control circuit 140 may control the operations of the base station 100. For example, the control circuit 140 may transmit and receive signals through the wireless communication circuit 110 or the backhaul communication circuit 120. Additionally, the control circuit 140 can write and read data into the memory 130. For this purpose, the control circuit 140 may include at least one processor.

According to the present disclosure, the control circuit 140 may generate appropriate precoding matrix information based on channel state information and/or frequency band between the wireless communication device (200 in FIG. 1) and the base station 100, and based on this You can create a TPMI RBG bitmap.

According to another embodiment of the present disclosure, the base station 100 may receive a PUSCH transmitted by a wireless communication device (200 in FIG. 1) through a plurality of transmission paths to which gains are allocated based on loss information.

FIG. 3 is a block diagram of the wireless communication device of FIG. 1 according to an exemplary embodiment of the present disclosure.

Referring to FIG. 3, the wireless communication device 200 of FIG. 1 may include a processor 210, a communication circuit 220, and a memory 230.

The processor 210 may control overall operations of the wireless communication device 200. For example, the processor 210 may transmit and receive signals through the communication circuit 220. Additionally, the processor 210 can write data to and read data from the memory 230. To this end, the processor 210 may include at least one processor or microprocessor, or may be part of a processor. When part of the processor, part of the communication circuit 220 and the processor 210 may be referred to as a communication processor (CP).

The communication circuit 220 may perform functions for transmitting and receiving signals with a base station (100 in FIG. 1) through a wireless channel. According to one embodiment, the communication circuit 220 may perform a conversion function between a baseband signal and a bit string according to physical layer standards. For example, when transmitting data, the communication circuit 220 may generate modulation symbols by encoding and modulating the transmission bit stream. For example, when receiving data, the communication circuit 220 may restore the received bit stream by demodulating and decoding the baseband signal. Additionally, the communication circuit 220 may up-convert a baseband signal into an RF band signal and transmit it through an antenna, or may down-convert an RF band signal received through an antenna into a baseband signal. To this end, the communication circuit 220 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC.

The communication circuit 220 can transmit and receive signals. Communication circuitry 220 may receive a downlink signal. The downlink signal may include a synchronization signal (SS), a reference signal (RS), system information, configuration message, control information, or downlink data. Additionally, communication circuitry 220 may transmit uplink signals. The uplink signal may include a random access-related signal or reference signal (e.g., sounding reference signal (SRS), DM-RS), or uplink data. According to the present disclosure, the communication circuit 220 can receive TPMI, RI, and TPMI RBG bitmaps from a base station (100 in FIG. 1).

The memory 230 may store data such as basic programs, application programs, and setting information for operation of the wireless communication device 200. The memory 230 may be comprised of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory.

When the wireless communication device 200 is in a codebook-based transmission mode, the memory 230 may store a precoding matrix set. In addition, when the processor 210 requests a precoding matrix selected based on TPMI and RI among the precoding matrix sets, the memory 230 selects the selected precoding matrix from the precoding matrix set stored in the memory 230 to the processor ( 210). Alternatively, when the processor 210 requests a plurality of precoding matrices applied to each of a plurality of RBGs based on the TPMI RBG bitmap, the plurality of precoding matrices may be provided to the processor 210.

According to the present disclosure, communication circuit 220 may receive TPMI and RI, and processor 210 may request a precoding matrix to be applied to PUSCH transmission from memory 230 based on TPMI and RI. Additionally, the processor 210 may calculate loss information for each of the first to Nth transmission paths 222-1 to 222-N in FIG. 4 . For example, the processor 210 may calculate loss information for each of a plurality of transmission paths through a calibration process of the transmission signal and/or a power difference between signals received through the plurality of transmission paths. The calculated loss information may be stored in memory 230. The processor 210 may calculate a gain allocation matrix based on loss information for each of the plurality of calculated transmission paths. The wireless communication device 200 transmits a precoded PUSCH to the base station (100 in FIG. 1) based on the precoding matrix selected by the TPMI and RI transmitted by the base station 100 and a gain allocation matrix based on loss information. You can. The gain allocation matrix will be described later with reference to FIG. 4.

FIG. 4 is a detailed block diagram of the communication circuit of FIG. 3 according to an exemplary embodiment of the present disclosure.

FIG. 4 can be explained with reference to FIG. 3 .

Referring to FIG. 4, the communication circuit 220 of FIG. 3 may include a precoding unit 221 and a first transmission path 222-1 to an N-th transmission path 222-N.

The encoding and modulation unit (not shown) may generate modulation symbols by performing constellation mapping. The wireless communication device (200 in FIG. 3) may map the modulation symbols to Ns transmission layers based on the RI received from the base station (100 in FIG. 1). Ns may be an integer greater than or equal to 1 and less than or equal to the number of antenna pods of the wireless communication device (200 in FIG. 3).

The precoding unit 221 may map the Ns transport layers to which the modulation symbols are mapped to the transmission antenna port of the wireless communication device (200 in FIG. 3) using a precoding matrix. If the number of transmission antenna ports is Nt, the precoding matrix may be a matrix with Nt rows and Ns columns. According to an exemplary embodiment of the present disclosure, the numbers N and Nt of transmission paths may be equal, and N and Nt may be integers greater than 1.

According to the present disclosure, loss information for each of the first to Nth transmission paths 222-1 to 222-N may be different. Loss information may refer to the degree to which the power of a signal transmitted through the transmission path changes due to the characteristics of the transmission path. For example, each of the plurality of transmission paths may include a switching element, and loss information of each of the plurality of transmission paths may be different depending on the characteristics and/or number of the switching elements. As described above, the processor (210 in FIG. 3) may calculate loss information for each of the plurality of transmission paths by calculating the calibration process and/or the power difference for each path of the received signal.

According to the present disclosure, a wireless communication device (200 in FIG. 3) can transmit a precoded PUSCH to a base station (100 in FIG. 1) based on a precoding matrix and a gain allocation matrix. That is, the wireless communication device (200 in FIG. 3) maps Ns transmission layers to Nt transmission antenna ports through the precoding unit 221 using a precoding matrix and a gain allocation matrix, and maps Nt transmission antenna ports to Nt transmission antenna ports. The PUSCH can be transmitted to the base station (100 in FIG. 1). The gain allocation matrix may be a matrix calculated by the processor (210 in FIG. 3) based on loss information for each of the plurality of transmission paths used for PUSCH transmission, and loss information for each of the plurality of transmission paths based on the gain allocation matrix. A gain corresponding to can be assigned. The gain allocation matrix (G) may be equal to Equation 1.

The gain allocation matrix (G) is a square matrix with Nt rows and Nt columns, and may be a diagonal matrix. Diagonal components of the gain allocation matrix (G) ( inside ) Each is relative loss information of the corresponding transmission path. For example, the relative loss information of the first transmission path 222-1 is , and the relative loss information of the Nt transmission path (222-N) is It can be.

According to the present disclosure, a wireless communication device (200 in FIG. 3) may transmit a precoded PUSCH through a gain allocation matrix (G) and a precoding matrix selected based on TPMI and RI. At this time, the selected precoding matrix may be a matrix with Nt rows and Ns columns. When transmitting the PUSCH to the base station (100 in FIG. 1), the wireless communication device (200 in FIG. 3) applies a matrix obtained by multiplying the selected precoding matrix and the gain allocation matrix (G) to convert the precoded PUSCH into a gain-assigned It can be transmitted to the base station (100 in FIG. 1) through Nt transmission paths (222-1 to 222-N).

Referring to the description of FIG. 3, the processor 210 according to the present disclosure can calculate loss information. For example, the processor 210 may calculate loss information for each of the Nt transmission paths 222-1 to 222-N. The loss information of the first transmission path 222-1 is , the loss information of the Nt transmission path (222-N) is It can be. The processor 210 calculates loss information for each of the Nt transmission paths 222-1 to 222-N, and calculates a gain based on the loss information for each of the Nt transmission paths 222-1 to 222-N. The allocation matrix (G) can be calculated. As described above, the gain allocation matrix G may be a diagonal matrix, and the processor 210 may calculate diagonal components of the gain allocation matrix G according to Equation 2 or Equation 3. That is, the loss information of each of the Nt transmission paths 222-1 to 222-N ( inside ) Based on the relative loss information of each of the Nt transmission paths 222-1 to 222-N ( inside ) can be calculated.

Relative loss information for each of the Nt transmission paths (222-1 to 222-N) calculated according to Equation 2 ( inside The gain allocation matrix (G) based on ) may be referred to as a Maximum Ratio Transmission (MRT)-based gain allocation matrix. When a wireless communication device (200 in FIG. 1) transmits a precoded PUSCH through a plurality of transmission paths with gains assigned based on an MRT gain allocation matrix, Nt transmission paths 222-1 to 222-N. It can be said that the MRT gain is allocated for . Precoding the PUSCH based on the MRT gain allocation matrix means allocating a relatively large gain to a transmission path with relatively small loss when allocating gain to the Nt transmission paths (222-1 to 222-N). it means. That is, in the case of MRT gain allocation, a gain can be allocated to each of the Nt transmission paths 222-1 to 222-N in inverse proportion to relative loss information.

Relative loss information for each of the Nt transmission paths (222-1 to 222-N) calculated according to Equation 3 ( inside ) The gain allocation matrix (G) based on ) may be referred to as the compensation gain allocation matrix. When a wireless communication device (200 in FIG. 1) transmits a precoded PUSCH through a plurality of transmission paths with gains allocated based on a compensation gain allocation matrix, Nt transmission paths 222-1 to 222-N. It can be said that compensation gain is allocated for . Precoding the PUSCH based on a compensation gain allocation matrix is a method of allocating a relatively large gain to a transmission path with relatively large loss when allocating gain to the Nt transmission paths (222-1 to 222-N). means. That is, in the case of compensation gain allocation, a gain can be allocated to each of the Nt transmission paths 222-1 to 222-N in proportion to the relative loss information.

Relative loss information for each of the Nt transmission paths 222-1 to 222-N ( inside ) is the same, the wireless communication device (200 in FIG. 1) can allocate the same gain to the Nt transmission paths (222-1 to 222-N), and the gain allocation matrix (G) is called the same gain allocation matrix. It can be referred to.

According to the present disclosure, the power consumed when transmitting a PUSCH to the base station (100 in FIG. 1) based on the MRT gain allocation matrix or the compensation gain allocation matrix may be the same, and further, the MRT gain allocation matrix or the compensation gain allocation matrix It may be the same as the power consumed when transmitting the PUSCH to the base station by using only the precoding matrix selected by TPMI and RI (for example, the same gain allocation matrix may be applied).

According to the present disclosure, assigning a gain to each of the Nt transmission paths 222-1 to 222-N means increasing the signal output from each of the Nt transmission paths 222-1 to 222-N. can do. For example, the wireless communication device (200 in FIG. 3) is included in a transmission path to which a relatively large gain is assigned by MRT gain allocation or compensation gain allocation among the Nt transmission paths 222-1 to 222-N. The output signal can be increased by increasing the input voltage of the amplifier.

Figure 5 is a diagram of signal exchange between a base station and a wireless communication device according to an exemplary embodiment of the present disclosure.

FIG. 5 can be explained with reference to FIG. 4 .

Referring to FIG. 5, in operation 510, the wireless communication device 200a may transmit a Sounding Reference Signal (SRS) to the base station 100a. The base station 100a may receive an SRS from the wireless communication device 200a and perform channel estimation between the base station 100a and the wireless communication device 200a based on the SRS. That is, the base station 100a can estimate the uplink channel based on SRS. The base station 100a can estimate downlink information based on channel reciprocity and SRS.

In operation 520, the wireless communication device 200a may receive a Transmit Precoding Matrix Indicator (TPMI) from the base station 100a. TPMI may be information that indicates a precoding matrix from the base station 100a based on the uplink channel estimation result described with reference to operation 510. For example, TPMI corresponds to an index of a precoding matrix set and may mean an index for selecting a PUSCH precoding matrix. The base station 100a may transmit RI along with TPMI to the wireless communication device 200a. RI may be information indicating a transmission rank determined to be appropriate by the base station 100a based on the uplink channel estimation result. Here, the transmission rank is the number of transmission layers and is therefore related to the precoder matrix to be used for transmission. The base station 100a may transmit TPMI and RI to the wireless communication device 200a through an uplink scheduling grant.

In operation 530, the wireless communication device 200a selects a precoding matrix based on TPMI and RI, and configures each of the plurality of transmission paths based on loss information and the precoding matrix of each of the plurality of transmission paths. The gain can be allocated to . As described above, the processor 210 of FIG. 4 may calculate loss information for each of a plurality of transmission paths and calculate relative loss information for each of the plurality of transmission paths based on the loss information (Equation 2 and Equation 3). The wireless communication device 200a may generate a gain allocation matrix based on relative loss information, and transmit PUSCH to the base station 100a through a plurality of transmission paths with gains allocated based on the gain allocation matrix and the selected precoding matrix. It can be sent to .

In operation 540, the wireless communication device 200a may transmit a Physical Uplink Shared Channel (PUSCH) to the base station 100a through a plurality of transmission paths to which gains are assigned based on a gain allocation matrix.

6A and 6B show simulation results according to example embodiments of the present disclosure.

FIGS. 6A and 6B can be explained with reference to FIG. 1 .

FIGS. 6A and 6B show a transmission antenna (e.g., the wireless communication device 200 of FIG. 1) when the wireless communication device 200 of FIG. 1 transmits a PUSCH (Physical Uplink Shared Channel) through two transmission paths. )'s transmitting antenna) and receiving antennas (e.g., receiving antennas of the base station 100 in FIG. 1) are each 2, and the relative loss information difference between the two transmitting paths is 3 dB, SNR (Signal to Noise Ratio) Indicates the spectral efficiency according to . In addition to the above conditions, Figure 6a shows the simulation result when the rank value is 1, and Figure 6b shows the simulation result when the rank value is 2.

SNR can represent the ratio of signal to noise. Specifically, a lower SNR may mean that there is more noise in the channel between the wireless communication device (200 in FIG. 1) and the base station (100 in FIG. 1), resulting in lower channel quality.

Spectral efficiency may refer to channel capacity. The higher the spectral efficiency, the better the channel condition between the wireless communication device (200 in FIG. 1) and the base station (100 in FIG. 1), and the wireless communication device (200 in FIG. 1) transmits to the base station (100 in FIG. 1). This may mean that the reliability of a precoded PUSCH signal is high.

Referring to Figure 6a, when the rank value is 1, it can be seen that the spectral efficiency when applying the MRT gain allocation matrix is higher than when applying the same gain allocation matrix and compensation gain allocation matrix in the entire SNR range.

Referring to FIG. 6b, it can be seen that when the rank value is 2, the spectral efficiency when applying the compensation gain allocation matrix is higher than when applying the same gain allocation matrix and the MRT gain allocation matrix in the entire SNR range.

Referring to FIGS. 6A and 6B, it can be seen that the gain allocation method with higher spectral efficiency varies depending on the rank value indicated by the RI received by the wireless communication device (200 in FIG. 1) from the base station (100 in FIG. 1). You can. Accordingly, the wireless communication device (200 in FIG. 1) can determine a more efficient gain allocation matrix for PUSCH transmission based on the RI received from the base station (100 in FIG. 1).

Figure 7 is a flowchart showing a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure.

FIG. 7 can be explained with reference to FIG. 1 .

Referring to FIG. 7, a wireless communication device (200 in FIG. 1) may transmit an SRS to a base station (100 in FIG. 1) (S100). The base station (100 in FIG. 1) may receive the SRS and perform channel estimation between the base station (100 in FIG. 1) and the wireless communication device (200 in FIG. 1).

The wireless communication device (200 in FIG. 1) may receive TPMI indicating a precoding matrix and RI indicating a rank value from a base station (100 in FIG. 1) (S200). The base station (100 in FIG. 1) may transmit RI indicating a rank value determined to be appropriate for communication based on the channel estimation result and TPMI indicating a precoder matrix to the wireless communication device (200 in FIG. 1).

The wireless communication device (200 in FIG. 1) may select a precoding matrix based on TPMI and RI (S300).

The wireless communication device (200 in FIG. 1) may allocate a gain to each of the plurality of transmission paths based on the loss information and precoding matrix of each of the plurality of transmission paths (S400). The wireless communication device (200 in FIG. 1) may calculate relative loss information of each of the plurality of transmission paths based on loss information of each of the plurality of transmission paths, and may calculate relative loss information of each of the plurality of transmission paths based on the relative loss information. Benefits can be allocated. For example, the wireless communication device (200 in FIG. 1) may allocate a gain to each of a plurality of transmission paths in proportion to relative loss information (compensation gain allocation) or in inverse proportion (MRT gain allocation).

According to the present disclosure, the wireless communication device (200 in FIG. 1) compares the difference in loss information of each of the plurality of transmission paths with a preset first threshold, and if the loss information difference is less than or equal to the preset first threshold, the same Benefits can be allocated. For example, referring to FIG. 4, the wireless communication device (200 in FIG. 1) determines that the difference between the loss information of the first transmission path 222-1 and the loss information of the second transmission path 222-2 is a preset threshold. If it is less than or equal to the value, the relative loss information of the first transmission path 222-1 and the second transmission path 222-2 can be calculated in the same way. Accordingly, the same gain may be assigned to the first transmission path 222-1 and the second transmission path 222-2.

According to another embodiment of the present disclosure, a wireless communication device (200 in FIG. 1) calculates the variance (hereinafter, loss variance value) of loss information for each of a plurality of transmission paths, and the loss variance value is preset. When the loss variance value compared to the second threshold is less than or equal to the preset second threshold, the same gain may be assigned to each of the plurality of transmission paths. For example, referring to FIG. 4, when N is 3, the wireless communication device (200 in FIG. 1) may have loss information of 3, 5, and 4 for each of the three transmission paths, and the preset threshold may be It can be 1. At this time, since the loss variance value is 2/3, the wireless communication device (200 in FIG. 1) can allocate the same gain to each of the three transmission paths through equal gain allocation. On the other hand, when the loss information of each of the three transmission paths is 2, 6, and 4, the loss distribution value is 8/3, so the wireless communication device (200 in FIG. 1) uses the above-described MRT gain allocation or compensation gain allocation. A gain can be assigned to each of the three transmission paths.

The preset first threshold and the preset second threshold may be values stored in the memory of FIG. 3, and the memory (230 in FIG. 3) may set the first threshold or the second threshold at the request of the processor (210 in FIG. 3). The threshold may be provided to the processor (210 in FIG. 3).

The wireless communication device (200 in FIG. 1) may transmit a PUSCH to the base station (100 in FIG. 1) through a plurality of transmission paths (S500). Each of the plurality of transmission paths is a path to which a gain is allocated based on a gain allocation matrix and a selected precoding matrix, and the strength of a signal output from a path to which a relatively large gain is allocated may be relatively large.

FIG. 8 is a diagram for explaining a TPMI RBG bitmap according to an exemplary embodiment of the present disclosure.

FIG. 8 can be explained with reference to FIG. 1 .

According to the present disclosure, the base station (100 in FIG. 1) can allocate frequency resources including a plurality of RBGs to be used by the wireless communication device (200 in FIG. 1) for PUSCH transmission, and assign a free frequency to be applied to each of the plurality of RBGs. A Transmit Precoding Matrix Indicator (TPMI) RBG bitmap indicating a coding matrix may be transmitted to a wireless communication device (200 in FIG. 1). Additionally, the base station (100 in FIG. 1) can transmit RI along with the TPMI RBG bitmap to the wireless communication device (200 in FIG. 1).

Referring to FIG. 8, the base station (100 in FIG. 1) transmits PUSCH to the wireless communication device (200 in FIG. 1) in the frequency region corresponding to the 1st RB (Resource Block) (RB0) to the 12th RB (RB11). It can be assigned to a frequency domain for

Each of the first Resource Block Group (RBG) (RBG0) to the third RBG (RBG3) may include at least one RB. For example, the first RBG may include the 1st to 4th RBs, the second RBG may include the 5th to 8th RBs, and the third RBG may include the 9th to 12th RBs. It can be included. That is, a plurality of RBs included in each of a plurality of RBGs may be continuous RBs in the frequency domain. For example, referring to FIG. 9, the first RBG (RBG0) has four consecutive RBs (the first RB (RB0), the second RB (RB1), the third RB (RB2), and the fourth RB in the frequency domain. RB (RB3)) may be included.

Referring to FIG. 8, the TPMI RBG bitmap may include information indicating different precoding matrices for each of the first RBG (RBG0), the second RBG (RBG1), and the third RBG (RBG2). Accordingly, the wireless communication device (200 in FIG. 1) receives the TPMI RBG bitmap and RI from the base station (100 in FIG. 1), and performs different precoding for each of the plurality of RBGs based on the TPMI RBG bitmap and RI. The PUSCH can be transmitted to the base station (100 in FIG. 1) by applying the matrix.

Applying a different precoding matrix to each of a plurality of RBGs may mean applying a different precoding matrix for each frequency band. Since the channel status between the wireless communication device (200 in FIG. 1) and the base station (100 in FIG. 1) may be different for each frequency, the wireless communication device (200 in FIG. 1) uses multiple signals based on the TPMI RBG bitmap and RI. By applying a different precoding matrix to each of the RBGs, the spectral efficiency compared to the SNR of PUSCH transmission to the base station 100 can be increased. The optimal precoding matrix applied to each of the plurality of RBGs to increase spectral efficiency may be determined considering channel status and frequency band.

Figure 9 is a diagram of signal exchange between a base station and a wireless communication device according to an exemplary embodiment of the present disclosure.

Referring to FIG. 9, in operation 910, the wireless communication device 200b may transmit a Sounding Reference Signal (SRS) to the base station 100b. The base station 100b may receive the SRS from the wireless communication device 200b and perform channel estimation between the base station 100b and the wireless communication device 200b based on the SRS. That is, the base station 100b can estimate the uplink channel based on SRS. The base station 100b can estimate downlink information based on channel reciprocity and SRS.

In operation 920, the wireless communication device 200b may receive a Transmit Precoding Matrix Indicator (TPMI) Resource Block Group (RBG) bitmap from the base station 100b. The TPMI RBG bitmap may include information indicating a different precoding matrix for each of a plurality of RBGs. This will be described later with reference to FIG. 9. The base station 100b may transmit an RI (Rank Indicator) along with a TPMI RBG bitmap to the wireless communication device 200b. RI may be information indicating a transmission rank determined by the base station 100b to be appropriate based on the uplink channel estimation result. Here, the transmission rank is the number of transmission layers and is therefore related to the precoder matrix to be used for transmission.

In operation 930, the wireless communication device 200b may transmit a PUSCH to the base station 100b by applying a different precoding matrix to each of the plurality of RBGs based on the TPMI RBG bitmap and RI.

Figure 10 shows simulation results according to an exemplary embodiment of the present disclosure.

FIG. 10 can be explained with reference to FIG. 1 .

FIG. 10 shows the transmission of a transmission antenna (e.g., the wireless communication device 200 in FIG. 1) when the wireless communication device 200 in FIG. 1 transmits a PUSCH (Physical Uplink Shared Channel) through two transmission paths. When the number of antennas) and receiving antennas (e.g., receiving antennas of the base station (100 in FIG. 1) in FIG. 1) are two each, spectral efficiency according to SNR (Signal to Noise Ratio) is indicated.

Referring to FIG. 10, when a wireless communication device (200 in FIG. 1) transmits a PUSCH by applying a different precoding matrix to each of a plurality of RBGs, the same precoding matrix is applied to each of the plurality of RBGs throughout the SNR period. It can be seen that the spectral efficiency is higher than when applied (conventional scheme).

Figure 11 is a flowchart showing a method of operating a base station according to an exemplary embodiment of the present disclosure.

FIG. 11 can be explained with reference to FIG. 1 .

Referring to FIG. 11, a base station (100 in FIG. 1) may receive a Sounding Reference Signal (SRS) from a wireless communication device (200 in FIG. 1) (S600).

The base station (100 in FIG. 1) may perform channel estimation for the wireless communication device (200 in FIG. 1) based on SRS (S700).

The base station (100 in FIG. 1) may allocate frequency resources including a plurality of RBGs based on the channel estimation result (S800). Each of the plurality of RBGs may include at least one RB (Resource Block), and the plurality of RBs included in one RBG may be consecutive RBs in the frequency domain.

The base station (100 in FIG. 1) may generate a TPMI RBG bitmap including information indicating a different precoding matrix for each of a plurality of RBGs (S900). The base station (100 in FIG. 1) provides a different precoding matrix for each of the plurality of RBGs in consideration of the channel state between the wireless communication device (200 in FIG. 1) and the base station (100 in FIG. 1) and/or the frequency band of the RBG. A TPMI RBG bitmap containing information indicating can be created.

The base station (100 in FIG. 1) may transmit the TPMI RBG bitmap to the wireless communication device (200 in FIG. 1) (S1000). The wireless communication device (200 in FIG. 1) receives the TPMI RBG bitmap, applies a different precoding matrix to each of a plurality of RBGs, and transmits a PUSCH to which a different precoding matrix is applied for each RBG to the base station (100 in FIG. 1). It can be sent to.

As above, exemplary embodiments have been disclosed in the drawings and specification. Although embodiments have been described in this specification using specific terms, these are merely used for the purpose of explaining the technical idea of the present disclosure and are not used to limit the meaning or scope of the present disclosure described in the claims. Therefore, those skilled in the art will understand that various modifications and other equivalent embodiments are possible therefrom. Therefore, the true technical protection scope of the present disclosure should be determined by the technical spirit of the attached claims.

Claims (10)

In a method of operating a wireless communication device,
Transmitting a Sounding Reference Signal (SRS) to a base station;
Receiving a Transmit Precoding Matrix Indicator (TPMI) indicating a precoding matrix and a Rank Indicator (RI) indicating a rank value from the base station;
selecting a precoding matrix based on the TPMI and the RI;
Allocating a gain to each of the plurality of transmission paths based on loss information of each of the plurality of transmission paths and the precoding matrix; and
A method of operation, comprising transmitting a Physical Uplink Shared Channel (PUSCH) through the plurality of transmission paths. According to paragraph 1,
The step of allocating the gain is,
generating a loss variance value by calculating the variance of loss information for each of the plurality of transmission paths; and
An operating method comprising allocating a gain to each of the plurality of transmission paths based on a result of comparing the loss variance value with a preset second threshold. According to paragraph 1,
The step of allocating the gain is,
further comprising calculating a gain allocation matrix by calculating relative loss information based on the loss information of each of the plurality of transmission paths,
Allocating a gain to each of the plurality of transmission paths based on the gain allocation matrix and the precoding matrix,
The gain allocation matrix is a square matrix including a plurality of diagonal components, and each of the plurality of diagonal components is corresponding relative loss information of each of the plurality of transmission paths. According to paragraph 1,
The step of allocating the gain is,
A method of operation, characterized in that the gain allocated to each of the plurality of transmission paths is inversely proportional to the relative loss information of each of the plurality of transmission paths. According to paragraph 1,
The step of allocating the gain is,
A method of operation, characterized in that a gain allocated to each of the plurality of transmission paths is proportional to relative loss information of each of the plurality of transmission paths. According to paragraph 1,
Each of the plurality of transmission paths includes a first transmission path and a second transmission path,
The step of allocating the gain is,
When the difference between the loss information of the first transmission path and the loss information of the second transmission path is less than or equal to a preset first threshold, the same gain is assigned to each of the first transmission path and the second transmission path. How to do it. In wireless communication devices (User Equipment),
A communication circuit that transmits a Sounding Reference Signal (SRS) to a base station and receives a Transmit Precoding Matrix Indicator (TPMI) indicating a precoding matrix and a Rank Indicator (RI) indicating a rank value from the base station; and
Selecting a precoding matrix based on the TPMI and the RI, calculating a gain allocation matrix based on loss information of each of the plurality of transmission paths, and based on the gain allocation matrix and the precoding matrix, the plurality of transmission a processor that assigns a gain to each of the paths;
A wireless communication device that transmits a Physical Uplink Shared Channel (PUSCH) to the base station through the plurality of transmission paths to which gains are assigned. In clause 7,
The gain allocation matrix is,
A wireless communication device, characterized in that: a square matrix including a plurality of diagonal components, each of the plurality of diagonal components being relative loss information based on loss information of each of the plurality of transmission paths. In clause 7,
The processor,
Calculating the variance of loss information for each of the plurality of transmission paths to generate a loss variance value, and assigning the same gain to each of the plurality of transmission paths when the loss variance value is less than or equal to a preset second threshold. Characterized by a wireless communication device. In a method of operating a wireless communication device (User Equipment),
Transmitting a Sounding Reference Signal (SRS) to a base station;
Receiving a Transmit Precoding Matrix Indicator (TPMI) RBG bitmap including information indicating a precoding matrix corresponding to each of a plurality of Resource Block Groups (RBGs) from the base station; and
Applying a different precoding matrix to each of the plurality of RBGs based on the RBG bitmap and transmitting a Physical Uplink Shared Channel (PUSCH) to the base station,
Each of the plurality of RBGs includes at least one RB (Resource Block).

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