CN116743218A - Wireless communication device, operation method thereof, and operation method of base station - Google Patents

Wireless communication device, operation method thereof, and operation method of base station Download PDF

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Publication number
CN116743218A
CN116743218A CN202310246481.3A CN202310246481A CN116743218A CN 116743218 A CN116743218 A CN 116743218A CN 202310246481 A CN202310246481 A CN 202310246481A CN 116743218 A CN116743218 A CN 116743218A
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China
Prior art keywords
precoder
base station
reference signal
pdsch
srs
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CN202310246481.3A
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Chinese (zh)
Inventor
尹泓植
吴眕宇
李俊镐
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Samsung Electronics Co Ltd
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Samsung Electronics Co Ltd
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Priority claimed from KR1020220083160A external-priority patent/KR20230133166A/en
Application filed by Samsung Electronics Co Ltd filed Critical Samsung Electronics Co Ltd
Publication of CN116743218A publication Critical patent/CN116743218A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0426—Power distribution
    • H04B7/043—Power distribution using best eigenmode, e.g. beam forming or beam steering
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H04B7/0632—Channel quality parameters, e.g. channel quality indicator [CQI]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Power Engineering (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Provided are a wireless communication device, an operating method thereof, and an operating method of a base station. The operation method of the wireless communication device comprises the following steps: transmitting a Sounding Reference Signal (SRS) to a base station; receiving a first reference signal to which a first precoder is applied from the base station; generating feedback information including at least one of a Rank Indicator (RI) and a Channel Quality Indicator (CQI) based on at least one of: (i) A relationship between the first precoder and a second precoder applied to a first Physical Downlink Shared Channel (PDSCH) by the base station based on the SRS; and (ii) a channel estimated using the first reference signal; transmitting the generated feedback information to the base station; and receiving a second PDSCH to which at least one of the second precoder, the RI, and the CQI is applied.

Description

Wireless communication device, operation method thereof, and operation method of base station
Cross Reference to Related Applications
The present application is based on and claims priority from korean patent application No.10-2022-0030328 filed on 3 months 10 of 2022 and korean patent application No.10-2022-0083160 filed on 7 months 6 of 2022, the disclosures of which are incorporated herein by reference in their entireties.
Technical Field
The present disclosure relates to wireless communication devices that transmit and receive data using Channel State Information (CSI) feedback.
Background
Precoding can be generally understood as a preprocessing method for optimizing single-stream beamforming or multi-stream beamforming and thereby improving data throughput. Precoding may involve measuring a communication channel using a reference signal and thereafter weighting the amplitude and phase of a signal transmitted from each of a plurality of transmit antennas according to the measured channel. For this purpose, a User Equipment (UE) may transmit a Sounding Reference Signal (SRS) to a Base Station (BS). The BS may estimate an uplink channel between the UE and the BS using the received SRS. The BS may design a precoder for the downlink channel using the estimated uplink channel. The precoder may be designed using the reciprocity of the estimated uplink channel and a Time Division Duplex (TDD) channel.
Additionally or alternatively, the BS can transmit a reference signal to the UE to identify channel information between the BS and the UE. For example, the BS may transmit channel state information-reference signals (CSI-RS) to identify channel information between the BS and the UE. The UE may identify a channel between the BS and the UE through the CSI-RS received from the BS. The UE may report feedback information about the identified channel to the BS. The feedback information may include a Precoding Matrix Indicator (PMI), a Rank Indicator (RI), and a Channel Quality Indicator (CQI). The BS may design an SRS-based precoder using the received feedback information and may use the precoder to transmit a Physical Downlink Shared Channel (PDSCH) to the UE.
By using the SRS-based precoder based on CSI feedback, data throughput of PDSCH is improved. Ongoing research continues to explore ways to further improve this PDSCH data throughput.
Disclosure of Invention
Embodiments of the inventive concept provide a wireless communication apparatus to transmit and receive data using CSI feedback and an operating method thereof.
According to one aspect of the inventive concept, there is provided a method of operating a wireless communication device, the method comprising: transmitting a Sounding Reference Signal (SRS) to a base station; receiving a first reference signal to which a first precoder is applied from the base station; generating feedback information including at least one of a Rank Indicator (RI) and a Channel Quality Indicator (CQI) based on at least one of: (i) A relationship between the first precoder and a second precoder applied to a first Physical Downlink Shared Channel (PDSCH) by the base station based on the SRS, and (ii) a channel estimated using the first reference signal; transmitting the generated feedback information to the base station; and receiving a second PDSCH to which at least one of the second precoder, the RI, and the CQI is applied.
According to another aspect of the inventive concept, there is provided a method of operating a base station, the method comprising: receiving a Sounding Reference Signal (SRS) from a wireless communication device; generating a second precoder based on the SRS; transmitting a first reference signal to which a first precoder is applied to the wireless communication apparatus; determining a Precoding Matrix Indicator (PMI) candidate set based on the first precoder and the second precoder; receiving feedback information regarding the first reference signal, the feedback information including at least one of a Rank Indicator (RI) and a Channel Quality Indicator (CQI); and transmitting a Physical Downlink Shared Channel (PDSCH) to which at least one of the first precoder, the RI, and the CQI is applied.
According to another aspect of the inventive concept, there is provided a wireless communication apparatus including: a Radio Frequency Integrated Circuit (RFIC) configured to: transmitting a Sounding Reference Signal (SRS) to a base station, and receiving a first reference signal to which a first precoder is applied from the base station; and a processor configured to generate feedback information including at least one of a Rank Indicator (RI) and a Channel Quality Indicator (CQI) based on at least one of: a relationship between the first precoder and a second precoder applied to a first PDSCH by the base station based on the SRS, and a channel estimated using the first reference signal. The RFIC may transmit the generated feedback information to the base station and receive a second PDSCH to which at least one of the second precoder, the RI, and the CQI is applied.
Drawings
Embodiments of the inventive concept will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which:
fig. 1A and 1B illustrate a wireless communication system according to an embodiment of the inventive concept;
fig. 2 is a flowchart illustrating an operation method of a UE and a base station according to an embodiment of the inventive concept;
Fig. 3 is a flowchart illustrating an operation method of a UE and a base station according to an embodiment of the inventive concept;
fig. 4A is a flowchart illustrating an operation method of a UE and a base station according to an embodiment of the inventive concept;
fig. 4B illustrates an operation method of a UE according to an embodiment of the inventive concept;
fig. 5A illustrates an operation method of a base station according to an embodiment of the inventive concept;
fig. 5B illustrates a quasi co-location (QCL) type suitable for use in embodiments of the inventive concept;
fig. 6 illustrates an operation method of a UE and a base station according to an embodiment of the inventive concept;
fig. 7A, 7B, 7C, and 7D illustrate example beamforming with Transmit and Receive Points (TRPs) according to various embodiments of the inventive concepts;
fig. 7E illustrates a method of operation of a UE and TRP according to an embodiment of the inventive concept;
fig. 8 is a block diagram illustrating a wireless communication device according to an embodiment of the inventive concept; and
fig. 9 is a block diagram illustrating an electronic device according to an embodiment of the inventive concept.
Detailed Description
Hereinafter, embodiments of the inventive concept will be described in detail with reference to the accompanying drawings.
Herein, a Base Station (BS) is a network element that communicates with a wireless communication device and allocates communication network resources to the wireless communication device. A base station is sometimes referred to as a cell, nodeB (NB), eNodB (eNB), next generation radio access network (NG RAN), radio access unit, base station controller, node on the network, gndeb (gNB), transmission and Reception Point (TRP), remote Radio Head (RRH), etc.
A wireless communication apparatus is an apparatus that communicates with a base station or another wireless communication apparatus and may be referred to as a node, a User Equipment (UE), a next generation UE (NG UE), a Mobile Station (MS), a Mobile Equipment (ME), an apparatus, a terminal, or the like.
Some examples of wireless communication devices include smart phones, tablet PCs, mobile phones, image phones, electronic book readers, desktop PCs, laptop PCs, wallets, netbook computers, PDAs, portable Multimedia Players (PMPs), MP3 players, medical devices, cameras, and wearable devices. Other examples include televisions, digital Video Disc (DVD) players, audio players, refrigerators, air conditioners, cleaners, ovens, microwave ovens, washing machines, air cleaners, set top boxes, home automation control panels, security control panels, media boxes (e.g., samsung HomeSync TM Apple TV TM Or google TV TM ) Game machine (e.g. Xbox) TM 、PlayStation TM ) Electronic dictionary, electronic key, video camera (video camera), and electronic photo frame. Yet other examples include at least one of: various medical devices (e.g., various portable medical measuring instruments (blood glucose meter, heart rate)A meter, a sphygmomanometer, or a thermometer), a Magnetic Resonance Angiography (MRA), a Magnetic Resonance Imaging (MRI), a Computed Tomography (CT), a photographic device, or an ultrasound device), a navigation device, a Global Navigation Satellite System (GNSS), an Event Data Recorder (EDR), a Flight Data Recorder (FDR), a vehicle infotainment device, a marine electronics (e.g., a marine navigation device, a gyrocompass, etc.), an avionics device, a security device, a vehicle head unit, an industrial or household robot, an unmanned aerial vehicle, an Automated Teller Machine (ATM) of a financial institution, a point of sale (POS) terminal of a store, or an internet of things device (e.g., a bulb, various sensors, a sprinkler device, a fire alarm, a temperature controller, a street lamp, a toaster, fitness equipment, a hot water tank, a heater, a boiler, etc.). Additional examples include various types of multimedia systems capable of performing communication functions.
Fig. 1A and 1B illustrate a wireless communication system according to an embodiment of the inventive concept. The wireless communication system may include a wireless communication device 120 and a base station 110. Hereinafter, the wireless communication apparatus 120 is referred to as a User Equipment (UE) 120. For ease of description, the wireless communication system is shown and described in the context of one base station 110 and one UE 120, but embodiments may be implemented with two or more base stations and/or UEs.
Base station 110 may connect wirelessly to UE 120 over a wireless channel to provide various communication services. Base station 110 may serve all user traffic over a shared channel and may collect and schedule status information such as buffer status, available transmit power status, and channel status of UE 120. A wireless communication system may support beamforming techniques by using an Orthogonal Frequency Division Multiplexing (OFDM) scheme as a radio access technology. In addition, the wireless communication system may support an Adaptive Modulation and Coding (AMC) scheme that determines a modulation scheme and a channel coding rate according to a channel state of the UE 120.
In an example, a wireless communication system transmits and receives signals using a wide frequency band including the 6GHz band. For example, wireless communication systems may use millimeter wave bands, such as 28GHz band or 60GHz band, to increase data transmission rates. In this case, since the millimeter wave band has a relatively large signal attenuation per distance, the wireless communication system can support directional beam-based transmission and reception generated using a plurality of antennas to secure coverage. The wireless communication system may be a system supporting Multiple Input and Multiple Output (MIMO), and thus, the base station 110 and the UE 120 may support beamforming techniques. Such beamforming techniques may include digital beamforming, analog beamforming, and/or hybrid beamforming.
Referring to fig. 1A, a base station 110 may transmit channel state information-reference signals (CSI-RS) to a UE 120. UE 120 may use CSI-RS to estimate a channel between base station 110 and UE 120. UE 120 may use the estimated channel to generate CSI feedback information including at least one of a Rank Indicator (RI), a Precoding Matrix Indicator (PMI), and Channel Quality Information (CQI). UE 120 may send the generated CSI feedback information to base station 110 in a CSI-RS report.
Referring to fig. 1b, ue 120 may transmit a Sounding Reference Signal (SRS) to base station 110. Base station 110 may estimate a channel between base station 110 and UE 120 using SRS obtained in a Time Division Duplex (TDD) transmission. The base station 110 may design a precoder that maximizes the capacity of the estimated channel. Base station 110 may use a designed precoder to transmit a Physical Downlink Shared Channel (PDSCH) to UE 120.
When the base station 110 transmits PDSCH to the UE 120 using the SRS-based precoder, the base station 110 may additionally schedule PDSCH using CSI feedback information.
For example, the base station 110 may calculate information about a relationship between a precoder of the CSI-RS and an SRS-based precoder and transmit the calculated information to the UE 120 so as to use CSI feedback information when transmitting the PDSCH using the SRS-based precoder. In addition, UE 120 may generate CSI feedback information corresponding to the PDSCH based on the received information.
As another example, UE 120 may measure the beamforming gain of PDSCH and measure the beamforming gain of CSI-RS, thereby predicting the relationship between the precoder of PDSCH and the precoder of CSI-RS. UE 120 may generate CSI feedback information corresponding to the PDSCH by using information on a relationship between a precoder of the PDSCH and a precoder of the CSI-RS. The following examples will describe these concepts in more detail.
Fig. 2 is a flowchart illustrating an operation method of a UE and a base station according to an embodiment of the inventive concept.
Referring to fig. 2, in operation S201, the UE 120 may transmit an SRS to the base station 110, and the base station 110 receives the SRS. Base station 110 may use the received SRS to estimate an uplink channel and a downlink channel between base station 110 and UE 120. In a TDD example, base station 110 may treat an estimated uplink channel between base station 110 and UE 120 as a downlink channel between base station 110 and UE 120 by using "SRS switching" based on reciprocity. In other words, although the uplink transmits the SRS, the base station 110 may design a downlink precoder using the uplink SRS. As described later, the base station may design the first precoder based on the SRS.
In operation S203, the base station 110 may design a first precoder applied to the first PDSCH. For example, the base station 110 may use the SRS to design a first precoder that maximizes the capacity of the estimated channel.
The first precoder may be a precoder that is not codebook-based. For example, the first precoder may comprise a eigenvector of a channel between the base station 110 and the UE 120. The first precoder may have a higher resolution than the codebook-based precoder. Thus, when the first precoder is used for data transmission, the data throughput may be higher than when the codebook-based precoder is used for data transmission. The base station 110 may design a first precoder that maximizes one or more metrics, e.g., average mutual information per coded bit (mean of the mutual information per coded bit, MMIB), by using the estimated channel.
In operation S205, the base station 110 may determine a beamforming gain. The base station 110 may calculate a beamforming gain of a Physical Downlink Shared Channel (PDSCH) to which the SRS-based first precoder is applied. To this end, the base station 110 may calculate a first beamforming gain to be implemented by the UE 120 when the UE 120 receives the PDSCH to which the SRS-based precoder is applied.
Meanwhile, the base station 110 may transmit the CSI-RS to which the second precoder is applied to the UE 120 (S209). The second precoder may be a precoder predetermined by the base station. For example, the second precoder may be a precoder based on CSI-RS reports received by the base station 110 from the UE 120. Base station 110 may calculate a second beamforming gain that may be achieved by UE 120 when UE 120 receives the CSI-RS to which the second precoder is applied. The first precoder may be different from the second precoder.
The base station 110 may calculate a first beamforming gain of a first precoder that maximizes a channel capacity of a channel based on SRS estimation and a second beamforming gain applied to a second precoder of the CSI-RS.
UE 120 may receive beamforming gain information from base station 110 (S207). Base station 110 may transmit first beamforming gain information regarding the SRS-based first precoder to UE 120. In addition, the base station 110 may transmit second beamforming gain information regarding a second precoder applied to the CSI-RS to the UE 120.
The base station 110 may transmit CSI-RS to the UE 120 (S209), and transmit beamforming gain information (S207) including first beamforming gain information of a first precoder based on SRS (e.g., beamforming gain obtained due to the first precoder) and second beamforming gain information of a second precoder applied to the CSI-RS (e.g., beamforming gain obtained due to the second precoder). For example, the base station 110 may transmit information about the ratio of the first beamforming gain to the second beamforming gain to the UE 120. The ratio of the first beamforming gain to the second beamforming gain may be expressed as follows.
[ 1]
In the formula (1) of the present invention,is the ratio (or difference) of the first beamforming gain to the second beamforming gain;is the channel between UE120 and base station 110; />Is a precoder that maximizes the capacity of a channel estimated based on SRS; />A second precoder used when the base station transmits the CSI-RS;the number of layers of data transmitted by the base station; />Is the number of antenna ports of the CSI-RS.
The beamforming gain information comprising the ratio of the first beamforming gain to the second beamforming gain may be referred to as a beamforming gain offset. The beamforming gain offset may be a ratio of a beamforming gain of PDSCH resource elements to a beamforming gain of non-zero power (NZP) CSI-RS resource elements. The beamforming gain offset may have a value in dB.
Base station 110 may transmit beamforming gain information to UE120 using any of the signaling schemes including Radio Resource Control (RRC), medium access control element (MACCE), and Downlink Control Information (DCI). For example, base station 110 may transmit a Radio Resource Control (RRC) signal including beamforming gain information to UE 120. As a specific example, the beamforming gain offset may be included in the NZP-CSI-RS-resource information element.
UE 120 may receive CSI-RS to which the second precoder is applied from base station 110 (S209). UE 120 may use the received CSI-RS to estimate a channel between base station 110 and UE 120.
In operation S211, the UE 120 may generate feedback information based on a relationship between the first precoder and the second precoder. The relationship between the first precoder and the second precoder may refer to a ratio of a first beamforming gain of the first precoder to a second beamforming gain of the second precoder. For example, UE 120 may generate CSI-RS feedback information using the received beamforming gain information.
UE 120 may calculate at least one of a Precoding Matrix Indicator (PMI), a rank, and a Channel Quality Indicator (CQI) using the received beamforming gain information and the estimated channel. For example, UE 120 may calculate a rank and PMI that maximizes capacity C of the estimated channel, where the rank and PMI may be expressed as equation 2:
[ 2]
In the formula (2) of the present invention,is the ratio (or difference) of the first beamforming gain to the second beamforming gain; />Is the rank to be reported by UE 120 using a Rank Indicator (RI); />Is the number of antenna ports of the CSI-RS; />Is a PMI codebook with rank L; and H is described below in conjunction with formula 3 CSI [k]. The channel capacity will be described later along with equation 4.
Regarding equation 2, the received signal of the CSI-RS may be expressed as equation 3:
[ 3]
In the case of the method of 3,is a CSI-RS received signal; />Is the channel between UE120 and base station 110; />Is a precoder used by a base station for CSI-RS transmission;is noise included in the received signal; and H is CSI [k]Is the product of the channel between UE120 and base station 110 and the precoder for CSI-RS transmission. UE120 may not receive +.>And->Thus, UE120 may estimate H CSI [k]Is a value of (2).
When PMI codebook with rank L is appliedWhen the channel capacity C can be expressed as expression 4:
[ 4]
In operation S213, the UE120 may transmit feedback information to the base station 110. For example, UE120 may transmit feedback information including a Rank Indicator (RI) and CQI calculated using beamforming gain information and an estimated channel to base station 110. CSI reporting of embodiments of the inventive concept is described herein based on subband CSI reporting. In other embodiments, CSI reporting is applied to wideband CSI reporting.
In operation S215, the base station 110 may perform scheduling on the second PDSCH. As described above, the base station 110 may perform scheduling on the second PDSCH using at least one of the SRS-based first precoder and feedback information received from the UE 120. For example, the base station 110 may perform scheduling on the second PDSCH using the SRS-based first precoder and at least one of RI and CQI received from the UE 120. The base station 110 may determine a rank for the second PDSCH using the received RI. The base station 110 may use the received CQI to determine a Modulation and Coding Scheme (MCS) for the second PDSCH. Accordingly, the base station 110 may determine at least one of rank and CQI suitable for the UE 120.
In operation S217, the UE 120 may receive a second PDSCH from the base station 110.
Fig. 3 is a flowchart illustrating an operation method of a UE and a base station according to an embodiment of the inventive concept.
Referring to fig. 3, in operation S301, the UE 120 may transmit an SRS to the base station 110. Base station 110 may receive the SRS from UE 120. Base station 110 may use the received SRS to estimate an uplink channel and a downlink channel between base station 110 and UE 120. In a TDD example, base station 110 may treat an estimated uplink channel between base station 110 and UE 120 as a downlink channel by using SRS based on reciprocity. As described later, the base station may design the first precoder based on the SRS.
In operation S303, the base station 110 may design a first precoder applied to a first PDSCH. Specifically, the base station 110 may design a first precoder that maximizes the capacity of the estimated channel using the SRS.
The first precoder may be a precoder that is not codebook-based. For example, the first precoder may comprise a eigenvector of a channel between the base station 110 and the UE 120. The first precoder may have a higher resolution than the codebook-based precoder. Thus, when the first precoder is used for data transmission, the data throughput may be higher relative to a codebook-based precoder implementation. The base station 110 may use the estimated channel to design a first precoder that maximizes at least one metric, such as MMIB.
In operation S305, the UE 120 may receive a first PDSCH from the base station 110. The base station 110 may apply a first precoder to the first PDSCH. The base station 110 may transmit a first PDSCH to which the first precoder is applied to the UE 120.
In operation S307, the UE 120 may measure a beamforming gain of the first precoder. To this end, the UE 120 may measure a beamforming gain of the first PDSCH to which the SRS-based first precoder is applied. For example, UE 120 may measure the beamforming gain of the first PDSCH by measuring the received power of the first PDSCH.
In operation S309, the UE 120 may receive the CSI-RS to which the second precoder is applied from the base station 110. The first precoder may be different from the second precoder. UE 120 may use the received CSI-RS to estimate a channel between base station 110 and UE 120.
In operation S311, the UE 120 may measure a beamforming gain of the second precoder. In particular, UE 120 may measure beamforming gain of CSI-RS to which the second precoder is applied. For example, UE 120 may measure the beamforming gain of the CSI-RS by measuring the received power of the CSI-RS.
UE 120 may estimate a ratio of a beamforming gain of the SRS-based first precoder to a beamforming gain of the second precoder applied to the CSI-RS. In particular, UE 120 may estimate a ratio of beamforming gains using the measured beamforming gain of the first precoder and the measured beamforming gain of the second precoder. The ratio of the beamforming gain may be expressed as in equation 1 above.
In operation S313, the UE 120 may generate feedback information based on a relationship between the first precoder and the second precoder. The relationship between the first precoder and the second precoder may refer to a ratio of a first beamforming gain of the first precoder to a second beamforming gain of the second precoder. For example, UE 120 may generate CSI-RS feedback information using the measured beamforming gain of the first precoder and the measured beamforming gain of the second precoder. In addition, UE 120 may generate CSI-RS feedback information using ratio information of the measured beamforming gain of the first precoder and the measured beamforming gain of the second precoder.
UE 120 may calculate at least one of PMI, RI, and CQI using the measured beamforming gain and the estimated channel. The rank and PMI may be calculated using channel and beamforming gain information estimated by the UE 120, and may be expressed as in equation 2.
In operation S315, the UE 120 may transmit feedback information to the base station 110. For example, UE 120 may transmit feedback information including a Rank Indicator (RI) and CQI calculated using the measured beamforming gain information and the estimated channel to base station 110.
In operation S317, the base station 110 may perform scheduling on the second PDSCH. As described above, the base station 110 may perform scheduling on the second PDSCH using at least one of the SRS-based first precoder and feedback information received from the UE 120. For example, the base station 110 may perform scheduling on the second PDSCH using the SRS-based first precoder and at least one of RI and CQI received from the UE 120. The base station 110 may determine a rank of the second PDSCH using the received RI. The base station 110 may use the received CQI to determine a Modulation and Coding Scheme (MCS) for the second PDSCH. Accordingly, the base station 110 may determine at least one of rank and CQI suitable for the UE 120.
In operation S319, the UE 120 may receive a second PDSCH from the base station 110.
Fig. 4A is a flowchart illustrating an operation method of a UE and a base station according to an embodiment of the inventive concept.
Referring to fig. 4A, in operation S401a, the UE 120 may transmit an SRS to the base station 110. Base station 110 may receive the SRS from UE 120. Base station 110 may use the received SRS to estimate an uplink channel and a downlink channel between base station 110 and UE 120. In a TDD example, base station 110 may treat an estimated uplink channel between base station 110 and UE 120 as a downlink channel between base station 110 and UE 120 by using SRS based on reciprocity. As described later, the base station may design the first precoder based on the SRS.
In operation S403a, the base station 110 may design a first precoder applied to the first PDSCH. Specifically, the base station 110 may design a first precoder that maximizes the capacity of the estimated channel using the SRS.
The first precoder may be a precoder that is not codebook-based. For example, the first precoder may comprise a eigenvector of a channel between the base station 110 and the UE 120. The first precoder may have a higher resolution than the codebook-based precoder. Thus, when the first precoder is used for data transmission, the data throughput may be higher compared to a codebook-based precoder implementation.
The base station 110 may use the estimated channel to design a first precoder that maximizes a metric, such as MMIB. The base station 110 may design a first precoder that maximizes various metrics and is not limited to the above-described embodiments.
In operation S405a, the UE 120 may receive a first PDSCH from the base station 110. The base station 110 may apply a first precoder to the first PDSCH. The base station 110 may transmit a first PDSCH to which the first precoder is applied to the UE 120.
In operation S407a, the UE 120 may measure a beamforming gain of the first precoder. Specifically, UE 120 may measure a beamforming gain of the first PDSCH to which the SRS-based first precoder is applied. For example, UE 120 may measure the beamforming gain of the first PDSCH by measuring the received power of the first PDSCH.
In operation S409a, the UE 120 may receive the CSI-RS to which the second precoder is applied from the base station 110. The first precoder may be different from the second precoder. UE 120 may use the received CSI-RS to estimate a channel between base station 110 and UE 120.
In operation S411a, the UE 120 may measure a beamforming gain of the second precoder. In particular, UE 120 may measure beamforming gain of CSI-RS to which the second precoder is applied. For example, UE 120 may measure the beamforming gain of the CSI-RS by measuring the received power of the CSI-RS.
UE 120 may estimate a ratio of a beamforming gain of the SRS-based first precoder to a beamforming gain of the second precoder applied to the CSI-RS. In particular, UE 120 may estimate a ratio of beamforming gains using the measured beamforming gain of the first precoder and the measured beamforming gain of the second precoder. The ratio of the beamforming gain may be expressed as in equation 1 above.
In operation S413a, the UE 120 may transmit a channel alignment request message to the base station 110. For example, when the measured beamforming gain of the first PDSCH is different from the measured beamforming gain of the CSI-RS, UE 120 may transmit a channel alignment request message to base station 110. UE 120 may request base station 110 to change the precoder of the CSI-RS by sending a channel alignment request message to base station 110. For example, UE 120 may request base station 110 to apply a first precoder of a first PDSCH to CSI-RS by sending a channel alignment request message to base station 110.
When the base station 110 receives the channel alignment request message from the UE 120, the base station 110 may apply a first precoder to the CSI-RS. In addition, when receiving the channel alignment request message from the UE 120, the base station 110 may design a precoder for the PDSCH without using a PMI codebook. The channel alignment request message may be referred to as a non-PMI based feedback request message. UE 120 may send a non-PMI based feedback request message to base station 110 by using any of the signaling schemes including RRC, MAC CE, and DCI. For example, UE 120 may send a UE assistance information message including a non-PMI based feedback request message to base station 110. The UE assistance information may be RRC signaling parameters.
In operation S415a, the base station 110 may determine a beam of the CSI-RS. For example, when receiving the channel alignment request message from the UE 120, the base station 110 may apply a precoder of the first PDSCH transmitted to the UE 120 to the CSI-RS.
In operation S417a, the UE 120 may receive the CSI-RS to which the first precoder is applied from the base station 110. Upon receiving the CSI-RS with the non-PMI set, the UE 120 may determine that the precoder of the CSI-RS and the precoder of the PDSCH are the same.
In operation S419a, the UE 120 may generate feedback information by using the CSI-RS to which the first precoder is applied. For example, UE 120 may estimate a channel between base station 110 and UE 120 by using CSI-RS to which the first precoder is applied. Further, the UE 120 may calculate feedback information including at least one of RI and CQI for maximizing the estimated channel.
In operation S421a, the UE 120 may transmit feedback information to the base station 110. UE 120 may send feedback information including the calculated RI and CQI to base station 110.
In operation S423a, the base station 110 may perform scheduling on the second PDSCH. As described above, the base station 110 may perform scheduling on the second PDSCH using at least one of the SRS-based first precoder and feedback information received from the UE 120. For example, the base station 110 may perform scheduling on the second PDSCH using the SRS-based first precoder and at least one of RI and CQI received from the UE 120. The base station 110 may determine a rank of the second PDSCH using the received RI. The base station 110 may use the received CQI to determine a Modulation and Coding Scheme (MCS) for the second PDSCH. Accordingly, the base station 110 may determine at least one of rank and CQI suitable for the UE 120.
In operation S425a, the UE 120 may receive the second PDSCH from the base station 110.
Fig. 4B illustrates an operation method of a UE according to an embodiment of the inventive concept. Specifically, fig. 4B illustrates an example of an operation method of the UE 120 in the case where the UE 120 measures the beamforming gain of the first precoder and the beamforming gain of the second precoder in fig. 4A.
In operation S401b, the UE 120 may measure a beamforming gain of each of the PDSCH and the CSI-RS. UE 120 may measure the received power of each of the first PDSCH and CSI-RS. UE 120 may calculate the beamforming gain of the first precoder by measuring the received power of the first PDSCH. UE 120 may calculate the beamforming gain of the second precoder by measuring the received power of the CSI-RS.
In operation S403b, the UE 120 may check whether the beamforming gain of the PDSCH is different from that of the CSI-RS.
In operation S405B, when the beamforming gain of the PDSCH is different from that of the CSI-RS (yes in fig. 4B), the UE 120 may transmit a channel alignment request message to the base station 110. UE 120 may request that base station 110 apply a precoder to CSI-RS by sending a channel-alignment request message to base station 110.
In operation S407B, when the beamforming gain of the PDSCH and the beamforming gain of the CSI-RS are the same (no in fig. 4B), the UE 120 may determine RI and CQI based on the received CSI-RS. In this case, it may have been considered that the precoder of the CSI-RS is the same as that of the PDSCH.
Fig. 5A illustrates an operation method of a base station according to an embodiment of the inventive concept.
Referring to fig. 5A, in operation S501, the UE 120 may transmit an SRS to the base station 110. Base station 110 may receive the SRS from UE 120. Base station 110 may use the received SRS to estimate an uplink channel and a downlink channel between base station 110 and UE 120. In a TDD example, base station 110 may treat an estimated uplink channel between base station 110 and UE 120 as a downlink channel between base station 110 and UE 120 by using SRS based on reciprocity. As described later, the base station may design the first precoder based on SRS switching.
In operation S503, the base station 110 may design a first precoder applied to the first PDSCH. Specifically, the base station 110 may design a first precoder that maximizes the capacity of the estimated channel using the SRS. The first precoder may be a precoder that is not codebook-based. For example, the first precoder may comprise a eigenvector of a channel between the base station 110 and the UE 120. The first precoder may have a higher resolution than the codebook-based precoder. Thus, when the first precoder is used for data transmission, the data throughput may be higher than when the codebook-based precoder is used for data transmission. The base station 110 may use the estimated channel to design a first precoder that maximizes at least one metric, such as MMIB.
In operation S505, the base station 110 may determine a beam of the CSI-RS. For example, the base station 110 may apply a first precoder to the CSI-RS. In this case, the base station 110 may inform the UE 120 that the first precoder for PDSCH transmission and the precoder for CSI-RS transmission have the same beamforming gain.
In operation S507, the UE 120 may receive beamforming gain information from the base station 110. For example, UE 120 may receive information from base station 110 that the first precoder for PDSCH transmission and the precoder for CSI-RS transmission have the same beamforming gain. The beamforming gain information may be expressed as in equation 5:
[ 5]
UE 120 may receive such beamforming gain information through higher layer signaling (higher layer signaling) associated with Transmission Configuration Information (TCI) status. For example, UE 120 may receive such beamforming gain information through quasi co-location (QCL) type signaling as a higher layer parameter.
In operation S509, the UE 120 may receive the CSI-RS to which the first precoder is applied from the base station 110. The UE 120 may confirm that the precoder applied to the first PDSCH and the precoder applied to the CSI-RS are the same based on QCL-type information including QCL-type-E received from the base station 110. UE 120 may use the received CSI-RS to estimate a channel between base station 110 and UE 120.
In operation S511, the UE 120 may generate feedback information by using the CSI-RS to which the first precoder is applied. UE 120 may calculate at least one of PMI, RI, and CQI. The rank and PMI may be calculated using channel and beamforming gain information estimated by the UE 120, and may be expressed as in equation 2.
In operation S513, the UE 120 may transmit feedback information to the base station 110. For example, UE 120 may transmit feedback information including a Rank Indicator (RI) and CQI calculated using beamforming gain information and an estimated channel to base station 110.
In operation S515, the base station 110 may perform scheduling on the second PDSCH. As described above, the base station 110 may perform scheduling on the second PDSCH using at least one of the SRS-based first precoder and feedback information received from the UE 120. For example, the base station 110 may perform scheduling on the second PDSCH using the SRS-based first precoder and at least one of RI and CQI received from the UE 120. The base station 110 may determine a rank of the second PDSCH using the received RI. The base station 110 may determine an MCS for the second PDSCH using the received CQI. Accordingly, the base station 110 may determine at least one of rank and CQI suitable for the UE 120.
In operation S517, the UE 120 may receive a second PDSCH from the base station 110.
Fig. 5B illustrates a quasi co-location (QCL) type suitable for use in embodiments of the inventive concept. Fig. 5B specifically illustrates an example of the quasi co-location (QCL) type described above in step S507 of fig. 5A.
Referring to fig. 5b, the channel characteristics of qcl-Type-a include doppler shift, doppler spread, average delay, and delay spread. The channel characteristics of QCL-Type-B include doppler shift and doppler spread. The channel characteristics of QCL-type-C include doppler shift and average delay. The channel characteristics of QCL-type-D include spatial Rx parameters. QCL-Type-D may mean that the wireless communication device shares the spatial Rx parameters acquired from the source signal with the target signal. The source signal may be referred to as a source channel. The target signal may be referred to as a target channel. The channel characteristics of QCL-Type-E may include beamforming gain parameters. The QCL-Type-E may include the identity between the beamforming gain of the reference signal precoder and the beamforming gain of the PDSCH precoder.
Hereinafter, a Transmission Configuration Indication (TCI) will be described. The base station may perform signaling of the TCI state, thereby informing the UE that the base station transmits PDSCH and Physical Downlink Control Channel (PDCCH) to the UE by using the same beam as the reference signal. That is, the base station may inform the UE that the PDSCH and the PDCCH are transmitted based on the same spatial filter as the specific reference signal. The TCI state may include information about the reference signal. For example, the TCI state may include information about at least one of a Synchronization Signal Block (SSB) and a channel state information-reference signal (CSI-RS). The base station may inform the UE of which TCI the PDSCH and PDCCH are related to through TCI status signaling.
Fig. 6 illustrates an operation method of a UE and a base station according to an embodiment of the inventive concept.
Referring to fig. 6, in operation S601, the UE 120 may transmit an SRS to the base station 110. Base station 110 may receive the SRS from UE 120. Base station 110 may use the received SRS to estimate an uplink channel and a downlink channel between base station 110 and UE 120. In a TDD example, base station 110 may treat an estimated uplink channel between base station 110 and UE 120 as a downlink channel between base station 110 and UE 120 by using SRS based on reciprocity. As described later, the base station may design the first precoder based on SRS switching.
In operation S603, the base station 110 may determine a precoder. The base station 110 may design a first precoder applied to the first PDSCH. Specifically, the base station 110 may design a first precoder that maximizes the capacity of the estimated channel using the SRS. The first precoder may be a precoder that is not codebook-based. For example, the first precoder may comprise a eigenvector of a channel between the base station 110 and the UE 120. The first precoder may have a higher resolution than the codebook-based precoder. Thus, when the first precoder is used for data transmission, the data throughput may be higher than when the codebook-based precoder is used for data transmission. The base station 110 may use the estimated channel to design a first precoder that maximizes at least one metric, such as MMIB.
In operation S605, the base station 110 may determine a beam of the CSI-RS. The base station 110 may apply a second precoder, different from the first precoder, to the CSI-RS. For example, the base station 110 may calculate the PMI candidate set. The PMI candidate set may be expressed as equation 6:
[ 6]
Wherein the method comprises the steps ofIs a precoder based on SRS switching for PDSCH transmission; />Is a PMI codebook; and->Is a precoder applied to CSI-RS by a base station. The base station 110 may calculate and identify a value of each of a precoder based on "SRS switching" and a precoder applied to CSI-RS. Referring to equation 6, the base station 110 may calculate a PMI candidate set having a minimum difference between a precoder based on SRS switching and a precoder applied to CSI-RS. The PMI candidate set may have one PMI fixed for each rank.
In addition, the base station 110 may apply a precoder applied to the PDSCH and a second precoder having most similar spatial domain characteristics to the CSI-RS based on any one PMI of the PMI candidate set.
In operation S607, the UE 120 may receive the PMI candidate set. The PMI candidate set may be referred to as a codebook subset restriction. The base station 110 may fix one PMI for each rank by transmitting a PMI candidate set to the UE 120. The base station 110 may omit the PMI by setting all bitmaps to 0.
In operation S609, the UE 120 may receive the CSI-RS to which the second precoder is applied from the base station 110. UE 120 may use the received CSI-RS to estimate a channel between base station 110 and UE 120.
In operation S611, the UE 120 may generate feedback information by using the CSI-RS to which the second precoder is applied. UE 120 may use the received PMI candidate set information to generate CSI-RS feedback information. For example, UE 120 may calculate at least one of RI and CQI using the received PMI candidate set information and the received CSI-RS.
In operation S613, the UE 120 may transmit CSI-RS feedback information to the base station 110. For example, the UE 120 may transmit feedback information including RI and CQI calculated using the PMI codebook to the base station 110.
In operation S615, the base station 110 may perform scheduling on the second PDSCH. As described above, the base station 110 may perform scheduling on the second PDSCH using at least one of the SRS-based first precoder and feedback information received from the UE 120. For example, the base station 110 may perform scheduling on the second PDSCH using the SRS-based first precoder and at least one of RI and CQI received from the UE 120. The base station 110 may determine a rank of the second PDSCH using the received RI. The base station 110 may determine an MCS for the second PDSCH using the received CQI. Accordingly, the base station 110 may determine at least one of rank and CQI suitable for the UE 120.
In operation S617, the UE 120 may receive data from the base station 110.
Fig. 7A to 7D illustrate example beamforming with Transmission and Reception Points (TRP) according to various embodiments of the inventive concepts. Each TRP shown in fig. 7A to 7D is an example of the base station 110.
Referring to fig. 7a, a ue 120 may connect to a network through a single Transmission and Reception Point (TRP) 130 and a single beam. Referring to fig. 7b, the ue 120 may be connected to the network through a plurality of TRPs 130 and 132 and one beam of each TRP. Referring to fig. 7c, the ue 120 may be connected to the network through a single TRP 130 and a plurality of beams formed by the TRP 130. Referring to fig. 7d, the ue 120 may be connected to the network through a plurality of TRPs 130 and 132 and a plurality of beams formed by each TRP.
The first TRP 130 and the second TRP 132 may transmit different PDSCH to the UE 120. Specifically, the first TRP 130 may transmit a first PDSCH to the UE 120, and the first TRP 132 may transmit a second PDSCH to the UE 120. For example, the first TRP 130 may transmit Downlink Control Information (DCI) to the UE 120 through a Physical Downlink Control Channel (PDCCH). In addition, the first PDSCH and the second PDSCH may be scheduled through a PDCCH transmitted by the first TRP 130. As another example, the first TRP 130 may transmit a first PDCCH controlling a first PDSCH to the UE 120, and the second TRP 132 may transmit a second PDCCH controlling a second PDSCH to the UE 120. Embodiments according to the inventive concept may be applied to communications between UE 120 and the plurality of TRPs 130 and 132.
For example, the plurality of TRPs 130 and 132 may transmit CSI-RS to UE 120, and the plurality of TRPs 130 and 132 may transmit the beamforming gain offset described above to UE 120.
In another example, UE 120 may predict a beamforming gain for each of PDSCH and CSI-RS with respect to each of the plurality of TRPs 130 and 132. The ratio of the beamforming gain to the nth TRP may be expressed as equation 7:
[ 7]
Where n is the TRP index.
In another example, UE 120 may send the above-described channel alignment request message to each of the plurality of TRPs 130 and 132. To this end, UE 120 may send a csi-ReportWithoutPMIRequest message for each of the plurality of TRPs 130 and 132.
In another example, UE 120 may signal each of the plurality of TRPs 130 and 132 that the beamforming gain of the precoder for PDSCH transmission is the same (within a predetermined tolerance) as the beamforming gain of the precoder for CSI-RS transmission. Such signaling may be defined as QCL-Type as described above. The equality (equality) of the beamforming gains can be expressed as in equation 8.
[ 8]
Where n is the TRP index. The UE 120 may be confirmed to receive signaling on equality of beamforming gains and obtain the same beamforming gain when CSI-RS and PDSCH are received from the plurality of TRPs 130 and 132. Thus, UE 120 may feed back to each of TRPs 130 and 132 a plurality of pieces of information calculated using the received CSI-RS.
As another example, each of the plurality of TRPs 130 and 132 may transmit a PMI candidate set to UE 120. The plurality of TRPs 130 and 132 may apply a precoder, which is most similar in spatial domain characteristics to a precoder used for PDSCH transmission, to the CSI-RS based on any one PMI of the PMI candidate set. UE 120 may feedback at least one of RI and CQI for each TRP. The PMI candidate set may be expressed as equation 9:
[ 9]
In formula 9, n is a TRP index.
The number of TRP may vary and is not limited to the above embodiments. Embodiments in accordance with the inventive concept may be applied to communications between UE 120 and a plurality of Remote Radio Heads (RRHs).
Fig. 7E illustrates an operation method of a UE and TRP according to an embodiment of the inventive concept.
In operation S701a, the UE 120 may transmit an SRS to the first TRP 130. In operation S701b, the UE 120 may transmit an SRS to the second TRP 132. In operation S703a, the first TRP 130 may determine a precoder. Specifically, the first TRP 130 may use the SRS to determine a precoder applied to the PDSCH. In operation S703b, the second TRP 132 may determine a precoder. In particular, the second TRP 132 may use the SRS to determine a precoder applied to the PDSCH.
In operation S705a, the first TRP 130 may calculate a beamforming gain of the SRS-based precoder and a beamforming gain of the CSI-RS precoder. The first TRP 130 may determine beamforming gain information based on the calculated beamforming gain. In operation S705a, the first TRP 130 may calculate a beamforming gain of the SRS-based precoder and a beamforming gain of the CSI-RS precoder. The second TRP 132 may determine beamforming gain information based on the calculated beamforming gain. In operation S708a, the UE 120 may receive beamforming gain information from the first TRP 130. In operation S707b, the UE 120 may receive beamforming gain information from the second TRP 132. In operation S711, the UE 120 may calculate at least one of RI and CQI for each of the first TRP 130 and the second TRP 132 using CSI-RS received from each of the first TRP 130 and the second TRP 132. UE 120 may generate CSI feedback information for each TRP.
In operation S713a, the UE 120 may transmit a CSI-RS report to the first TRP 130. In operation S713b, the UE 120 may transmit the CSI-RS report to the second TRP 132. In operation S715a, the first TRP 130 may determine at least one of rank and MCS. The first TRP 130 may schedule PDSCH using SRS-based precoders and CSI feedback information received from the UE 120. In operation S715b, the second TRP 132 may determine at least one of rank and MCS. The second TRP 132 may schedule PDSCH using SRS-based precoders and CSI feedback information received from UE 120. In operation S717a, the first TRP 130 may transmit the PDSCH to the UE 120. In operation S717b, the second TRP 132 may transmit the PDSCH to the UE 120. The sequence of operation method for each TRP of UE 120 is not limited to the above embodiments.
Fig. 8 is a block diagram illustrating a wireless communication apparatus according to an embodiment of the inventive concept.
Referring to fig. 8, a wireless communication device 20 (UE 120 of fig. 1) may include at least one processor 210 and at least one RFIC 220. The processor 210 may control the RFIC 220 and may be configured to implement the method of operation and the flow of operation of the wireless communication device 20 of the inventive concept. The wireless communication device 20 may include multiple antennas and the RFIC 220 may transmit and receive wireless signals via one or more antennas. At least some of the plurality of antennas may correspond to transmit antennas. The transmitting antenna may transmit wireless signals to an external device, such as another User Equipment (UE) or a Base Station (BS), instead of the wireless communication device 20. At least some of the remaining plurality of antennas may correspond to receive antennas. The receiving antenna may receive a wireless signal from an external device.
As an example, the wireless communication device 20 may include: an RFIC 220 that transmits a Sounding Reference Signal (SRS) to a base station and receives a first reference signal to which a first precoder is applied from the base station; and a processor 210 that generates feedback information including at least one of RI and CQI based on at least one of: a relationship between a first precoder and a second precoder applied to a first Physical Downlink Shared Channel (PDSCH) by a base station based on SRS, and a channel estimated using a first reference signal. The first reference signal may include at least one of: channel state information-reference signal, synchronization signal block, demodulation-reference signal, and tracking reference signal.
The RFIC 220 may transmit the generated feedback information to the base station and receive a second PDSCH to which at least one of a second precoder, RI, and CQI is applied.
Fig. 9 is a block diagram illustrating an electronic device 1000 according to an embodiment of the inventive concept. Referring to fig. 9, the electronic device 1000 may include a memory 1010, a processor unit 1020, an input/output control unit 1040, a display unit 1050, an input device 1060, and a communication processing unit 1090. Here, the memory 1010 may be provided with a plurality of memory cells.
The memory 1010 may include a program storage unit 1011 that stores a program for controlling the operation of the electronic apparatus and a data storage unit 1012 that stores data generated during the execution of the program. Data storage unit 1012 may store data necessary for the operation of application 1013 and CSI-RS density determining program 1014. Program storage unit 1011 may include application 1013 and CSI-RS density determining program 1014. Here, the program included in the program storage unit 1011 may be expressed as an instruction set or a set of instructions.
The applications 1013 include applications running in electronic devices. That is, the application 1013 may include instructions of an application driven by the processor 1022. According to an embodiment of the inventive concept, the CSI-RS feedback determination procedure 1014 may generate CSI-RS feedback based on a relationship between a precoder of the PDSCH and a precoder of the CSI-RS.
The peripheral interface 1023 may control the connection between the input/output peripheral of the base station and each of the processor 1022 and the memory interface 1021. Processor 1022 controls the base station to provide the corresponding service using at least one software program. In this case, the processor 1022 may run at least one program stored in the memory 1010 to provide a service corresponding to the corresponding program.
The input/output control unit 1040 may provide an interface between an input/output device such as the display unit 1050, the input device 1060, and the peripheral device interface 1023. The display unit 1050 displays status information, input characters, moving pictures, still pictures, and the like. For example, display unit 1050 may display application information driven by processor 1022.
The input device 1060 may provide input data generated by selection of an electronic device to the processor unit 1020 through the input/output control unit 1040. In this case, the input device 1060 may include a keypad having at least one hardware button, a touch pad sensing touch information, and the like. For example, the input device 1060 may provide touch information (such as touches, touch movements, touch releases, etc.) sensed by the touch panel to the processor 1022 through the input/output control unit 1040. The electronic apparatus 1000 may include a communication processing unit 1090 that performs a communication function for voice communication and data communication.
While the present inventive concept has been particularly shown and described with reference to embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the appended claims.

Claims (20)

1. A method of operation of a wireless communication device, the method of operation comprising:
sending SRS (sounding reference signal) to a base station, wherein the SRS is a sounding reference signal;
receiving a first reference signal to which a second precoder is applied from the base station;
feedback information including at least one of RI and CQI is generated based on at least one of: (i) A relationship between the second precoder and a first precoder applied to a first PDSCH by the base station based on the SRS; and (ii) a channel estimated using the first reference signal, the RI being a rank indicator, the CQI being a channel quality indicator, the PDSCH being a physical downlink shared channel;
transmitting the generated feedback information to the base station; and
a second PDSCH to which at least one of the first precoder, the RI, and the CQI is applied is received.
2. The method of operation of claim 1, wherein the first reference signal comprises at least one of: channel state information-reference signal, synchronization signal block, demodulation-reference signal, and tracking reference signal.
3. The method of operation of claim 1, wherein the relationship between the first precoder and the second precoder comprises: a gain ratio of a first beamforming gain of the first precoder to a second beamforming gain of the second precoder.
4. The method of operation of claim 3, further comprising: a beamforming gain offset is received from the base station indicating the gain ratio.
5. The method of operation of claim 3, wherein generating the feedback information comprises:
measuring a first received power of the first PDSCH and a second received power of the first reference signal; and
a ratio of the first received power to the second received power is calculated as the gain ratio.
6. The method of operation of claim 1, wherein the relationship between the first precoder and the second precoder comprises equality between the first precoder and the second precoder, and generating the feedback information comprises: checking whether the first precoder and the second precoder are identical.
7. The method of operation of claim 6, wherein,
Checking whether the first precoder and the second precoder are identical includes:
measuring a first received power of the first PDSCH and a second received power of the first reference signal;
comparing the measured first received power with the measured second received power; and
based on the comparison result, it is determined whether the first precoder and the second precoder are identical.
8. The method of operation of claim 6, wherein checking whether the first precoder and the second precoder are identical comprises: determining whether the first precoder and the second precoder are identical based on QCL information, i.e., quasi co-sited information, received from the base station.
9. The method of operation of claim 8, wherein the QCL information is defined as a type indicating that a first beamforming gain of the first precoder and a second beamforming gain of the second precoder are the same.
10. The method of operation of claim 6, wherein,
generating the feedback information includes:
requesting the base station to transmit a second reference signal to which the first precoder is applied when the first precoder is different from the second precoder;
Receiving the second reference signal from the base station; and
the feedback information is determined based on a channel estimated using the second reference signal.
11. A method of operation of a base station, the method of operation comprising:
receiving an SRS, i.e., a sounding reference signal, from a wireless communication device;
generating a first precoder based on the SRS;
transmitting a first reference signal to which a second precoder is applied to the wireless communication apparatus;
determining a PMI candidate set based on the first precoder and the second precoder, the PMI being a precoding matrix indicator;
receiving feedback information about the first reference signal, the feedback information including at least one of RI, which is a rank indicator, and CQI, which is a channel quality indicator; and
a physical downlink shared channel to which at least one of the second precoder, the RI, and the CQI is applied is transmitted.
12. The method of operation of claim 11 wherein determining the PMI candidate set comprises: one PMI is determined for each rank.
13. The method of operation of claim 12 wherein determining the PMI candidate set comprises: for each rank, a PMI that produces a minimum difference between the first precoder and the second precoder is determined.
14. The method of operation of claim 13, wherein the RI and the CQI are generated by the wireless communication apparatus by using the determined first PMI candidate set.
15. A wireless communication device, the wireless communication device comprising:
an RFIC configured to: transmitting an SRS to a base station, and receiving a first reference signal to which a second precoder is applied from the base station, the RFIC being a radio frequency integrated circuit, the SRS being a sounding reference signal; and
a processor configured to generate feedback information including at least one of RI and CQI based on at least one of: (i) A relationship between the second precoder and a first precoder applied to a first PDSCH by the base station based on the SRS; and (ii) a channel estimated using the first reference signal, the RI being a rank indicator, the CQI being a channel quality indicator, the PDSCH being a physical downlink shared channel;
wherein the RFIC transmits the generated feedback information to the base station and receives a second PDSCH to which at least one of the first precoder, the RI, and the CQI is applied.
16. The wireless communications apparatus of claim 15, wherein the first reference signal comprises at least one of: channel state information-reference signal, synchronization signal block, demodulation-reference signal, and tracking reference signal.
17. The wireless communications apparatus of claim 15, wherein the relationship between the first precoder and the second precoder comprises a gain ratio of a first beamforming gain of the first precoder to a second beamforming gain of the second precoder.
18. The wireless communications apparatus of claim 17, wherein the RFIC receives from the base station a beamforming gain offset that indicates the gain ratio.
19. The wireless communications apparatus of claim 17, wherein generating the feedback information comprises:
measuring, by the RFIC, a first received power of the first PDSCH and a second received power of the first reference signal; and
a ratio of the first received power to the second received power is calculated by the processor as the gain ratio.
20. The wireless communications apparatus of claim 15, wherein the relationship between the first precoder and the second precoder comprises equality between the first precoder and the second precoder, and generating the feedback information comprises: checking, by the processor, whether the first precoder and the second precoder are identical.
CN202310246481.3A 2022-03-10 2023-03-10 Wireless communication device, operation method thereof, and operation method of base station Pending CN116743218A (en)

Applications Claiming Priority (3)

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KR10-2022-0030328 2022-03-10
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