CN110535498B - Channel State Information (CSI) feedback method and equipment - Google Patents
Channel State Information (CSI) feedback method and equipment Download PDFInfo
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- CN110535498B CN110535498B CN201811625788.XA CN201811625788A CN110535498B CN 110535498 B CN110535498 B CN 110535498B CN 201811625788 A CN201811625788 A CN 201811625788A CN 110535498 B CN110535498 B CN 110535498B
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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
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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
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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
- H04B7/06—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
- H04B7/0626—Channel coefficients, e.g. channel state information [CSI]
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Abstract
The embodiment of the invention discloses a method and equipment for feeding back Channel State Information (CSI), wherein one mode comprises the following steps: the terminal feeds back precoding matrix information, wherein the precoding matrix information comprises first base vector information, second base vector information, and amplitude and phase information of a second coefficient; the precoding vectors in the feedback precoding sub-band are linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors. Therefore, the CSI feedback cost can be reduced, and the higher CSI feedback performance is ensured.
Description
Technical Field
The embodiments of the present invention relate to, but not limited to, wireless communication technologies, and in particular, to a method and an apparatus for CSI feedback.
Background
In a MIMO (Multiple-Input Multiple-Output) wireless communication system, the purpose of improving transmission efficiency and reliability can be achieved by precoding or beamforming Multiple transmit antennas. In order to implement high-performance precoding or beamforming, a precoding matrix or a beamforming vector needs to be well matched with a Channel, which requires that a transmitting end can better obtain Channel State Information (CSI). Therefore, CSI feedback is a key technique to achieve high performance precoding or beamforming in MIMO systems. However, when CSI feedback is performed, quantization feedback on a channel matrix may cause relatively large feedback overhead, and especially when CSI feedback with a large bandwidth is supported, the feedback overhead is an important issue for limiting performance improvement
Disclosure of Invention
In view of this, an embodiment of the present invention provides a method for feeding back CSI, including: the terminal feeds back precoding matrix information, wherein the precoding matrix information comprises first base vector information, second base vector information, and amplitude and phase information of a second coefficient;
the precoding vectors in the feedback precoding sub-band are linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
The embodiment of the invention also provides a Channel State Information (CSI) feedback method, which comprises the following steps:
a base station receives precoding matrix information fed back by a terminal, wherein the precoding matrix information comprises first base vector information, second base vector information and amplitude and phase information of a second coefficient;
the precoding vectors in the feedback precoding sub-band are linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
An embodiment of the present invention further provides a terminal, including:
the feedback unit is used for feeding back precoding matrix information, wherein the precoding matrix information comprises first base vector information, second base vector information and amplitude and phase information of a second coefficient;
feeding back a precoding vector in a precoding subband, wherein the precoding vector is linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
An embodiment of the present invention further provides a base station, including:
the terminal comprises a receiving unit, a processing unit and a processing unit, wherein the receiving unit is used for receiving precoding matrix information fed back by the terminal, and the precoding matrix information comprises first base vector information, second base vector information and amplitude and phase information of a second coefficient;
feeding back a precoding vector in a precoding subband, wherein the precoding vector is linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
The embodiment of the present invention further provides a terminal, which includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor, and when the computer program is executed by the processor, the method for channel state information CSI feedback executed by the terminal is implemented.
The embodiment of the invention also provides a base station, which comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor, wherein when the computer program is executed by the processor, the method for the CSI feedback executed by the base station is realized.
An embodiment of the present invention further provides a computer-readable storage medium, where an information processing program is stored on the computer-readable storage medium, and when the information processing program is executed by a processor, the method for implementing any one of the above channel state information CSI feedback is implemented.
Compared with the prior art, the embodiment of the invention provides a Channel State Information (CSI) feedback method and equipment, and the CSI feedback cost can be reduced and higher CSI feedback performance is ensured by feeding back the first base vector information, the second base vector information and the amplitude and phase information of the second coefficient.
Additional features and advantages of the invention will be set forth in the description which follows.
Drawings
Fig. 1 is a schematic flowchart of a CSI feedback method according to a first embodiment of the present invention;
fig. 2 is a schematic flowchart of a CSI feedback method according to a second embodiment of the present invention;
fig. 3 is a schematic flow chart of a CSI feedback method according to an embodiment of the present invention
Fig. 4 is a schematic flowchart of a CSI feedback method according to a second embodiment of the present invention;
fig. 5 is a schematic structural diagram of a terminal according to a third embodiment of the present invention;
fig. 6 is a schematic structural diagram of a base station according to a fourth embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
The steps illustrated in the flow charts of the figures may be performed in a computer system such as a set of computer-executable instructions. Also, while a logical order is shown in the flow diagrams, in some cases, the steps shown or described may be performed in an order different than here.
The CSI quantization feedback technique is an important component of the MIMO technique. In a conventional wireless communication system, a DFT (Discrete Fourier Transform) vector or a variation form of the DFT vector, such as a kronecker product of a plurality of DFT vectors, or a concatenated form of DFT vectors, or a form of performing phase adjustment on the concatenated DFT vectors, is generally used, and a terminal reports precoding indication information in the above form to a base station through quantization feedback. This type of precoding codebook can be classified as a first type of codebook, which has low overhead, but low CSI quantization precision and limited performance. Another codebook is obtained by performing linear weighted combination on DFT vectors or kronecker products of DFT vectors, the weighted combined vectors are called codebook base vectors, and codebook base vector related information, amplitude and phase information of weighting coefficients are fed back to a base station as precoding indication information, such a precoding codebook can be classified as a second type codebook. Specifically, in the second type of codebook technology, the column number of the precoding matrix fed back by the terminal, that is, the channel Rank, is RI (Rank indicator), where the precoding vector of each layer is represented as a linear combination of a group of codebook base vectors, the group of codebook base vectors may be referred to as a first base vector, the terminal calculates a weighting coefficient for the linear combination according to the first base vector, and quantizes amplitude and phase information of the feedback weighting coefficient, and the weighting coefficient may be referred to as a first coefficient. In order to improve the performance of feedback, it is usually necessary to report the amplitude and phase information of the first coefficient by sub-band. The sub-band is a frequency domain granularity, and for all RBs (Resource blocks) included in the CSI feedback bandwidth, a plurality of consecutive RBs form a sub-band.
For the CSI feedback method, the precoding of a certain layer on a subband can be expressed as:
wherein, W 1 Comprising 2L first basis vectors, W 1 Dimension of N t X 2L, of the form:
wherein b is 0 ,b 1 ,…,b L-1 Formed by a set of orthogonal DFT vectors or the kronecker product of DFT vectors, whose dimensions areIs composed of
Wherein N is t The number of ports of a CSI-RS (Channel State Information Reference Signal) is indicated. In the CSI feedback mode, the same DFT vector or the kronecker product of the DFT vector is adopted for the antenna ports with different polarization directions, so W 1 2L first basis vectors are included. In general, W 1 Is wideband fed back, i.e. W is for different subbands in the whole CSI feedback band 1 The information in (1) is the same.
Dimension (2L × 1) represents weighting coefficients of 2L first basis vectors, which are referred to as first coefficients.
Generally, in order to improve the performance of the second type codebook, the terminal needs to feed back the phase and/or amplitude information of the weighting coefficients of the respective codebook base vectors for each subband. Therefore, the second type codebook feedback brings a large CSI feedback overhead when the number of subbands is large. On the other hand, if only the information of the amplitude or phase of the weighting coefficient is fed back over the whole wideband, the high performance gain that can be brought by the second type codebook feedback cannot be sufficiently obtained. Therefore, how to obtain higher feedback performance of the second type codebook through smaller feedback overhead is an unsolved problem in the prior art.
Therefore, the embodiment of the invention provides a new CSI feedback scheme, which can reduce CSI feedback overhead and ensure higher CSI feedback performance.
Implementation mode one
Fig. 1 is a schematic flow chart of a CSI feedback method according to a first embodiment of the present invention, as shown in fig. 1, the method includes:
feeding back a precoding vector in a precoding subband, wherein the precoding vector is linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
Wherein the second basis vectors represent K DFT basis vectors selected from a DFT matrix or an oversampled DFT matrix having an oversampling factor O f The value of (a) is one of the following: 1. 2, 4 and 8.
Before the terminal feeds back the precoding matrix information, the method further comprises the following steps:
receiving a frequency domain range of CSI to be fed back, which is sent by a base station, wherein the frequency domain range of the CSI comprises: a precoding sub-band requiring CSI feedback, or a precoding sub-band requiring CSI comb feedback and sparsity, or a precoding sub-band not requiring CSI feedback;
when the base station comb configures a precoding sub-band which needs to feed back precoding information, the second base vector is corrected by one of the following modes:
the first method is as follows: the base station configures a larger oversampling factor and increases the number of selectable DFT matrixes;
the second method comprises the following steps: the terminal comb-intercepts DFT base vectors according to the pre-coding sub-bands of the pre-coding information needing to be fed back;
or, when the base station configures a part of the sub-bands which do not need to feed back precoding information, cutting off corresponding position elements of the precoding sub-bands which do not need to feed back precoding information in the DFT base vector;
or the base station configures whether to perform phase rotation on the second base vector or not, and takes the configured middle pre-coding sub-band as reference.
The CSI feedback band refers to a frequency domain range in which the base station needs to feed back CSI.
The precoding sub-band is a frequency domain unit, and the number of RBs contained in the precoding sub-band is configured by a base station or fed back by CSIThe number of RBs included in the frequency band and the second number of basis vectors used, i.e. including the number of RBs of
RBNum is the number of RBs contained in the CSI feedback frequency band, and K is the number of second base vectors used by the CSI feedback frequency band.
Wherein the second coefficient is expressed as
Has a dimension of 2L × K,2L represents the matrix W 1 K denotes a matrix W 3 K second basis vectors contained in (a).
Before the terminal feeds back the precoding matrix information, the method further comprises the following steps:
receiving a feedback mode and a feedback subset indication of a second coefficient sent by a base station;
feeding back a second coefficient in the precoding matrix information by one of the following modes:
the first method is as follows: feeding back a second coefficient according to the priority level of the amplitude of the second coefficient;
the second method comprises the following steps: feeding back a second coefficient by taking the first base vector as priority;
the third method comprises the following steps: feeding back a second coefficient by taking the second base vector as priority;
the method four comprises the following steps: dividing the first base vectors into two groups, and dividing the 1 st to Lth first base vectors, namely W 1 As a first group, the L +1 to the 2L first base vectors, i.e., W 1 As a second group, feeding back a second coefficient according to the priority inside the packet;
the fifth mode is as follows: and grouping the second coefficients, and feeding back the second coefficients according to the priority of the grouping.
Wherein, the first mode includes:
sorting the amplitude of the second coefficient, selecting partial coefficients from large to small until the ratio of the sum of the powers of the partial coefficients to the total power of the second coefficient is not less than delta, and feeding back the partial coefficients by the terminal, wherein the delta is a preset threshold;
the coefficients selected are indicated using a 2L · K sized bitmap.
Wherein, the second mode includes:
mode A: selecting l from K weighting coefficients of the optimal first basis vector 0 A coefficient, which is selected from the K weighting coefficients of the first base vectors 1 Coefficient of l 1 ＜l 0 The selected coefficients are indicated using a bitmap of 2L · K size;
alternatively, the mode B: selecting l from K weighting coefficients of the optimal first basis vector 0 A coefficient, and selecting M-l in total from all the weighting coefficients of the rest first base vectors 0 The coefficient is fed back, the value of M is configured by the base station or is
Wherein delta M Is a preset threshold value; feeding back its selected subset using one of the following sub-ways: subformulae B-1: the coefficients selected are indicated using a bitmap of 2L · K size; sub-mode B-2: use of
Indicating the selected optimal first basis vector for reuse
The remaining M-l indicating its selection 0 A coefficient;
alternatively, the mode C: 2L first base vectors are sequenced, and L are respectively selected from the weighting coefficients of the strong first base vectors to the weak first base vectors 0 ,l 0 -1，...,l 0 -M +1 coefficients are fed back, the selected coefficients being indicated using a bitmap of size 2L · K.
Wherein, mode three includes:
mode D, at the optimal second basis vectorSelecting L from 2L weighting coefficients of the quantity 0 A coefficient, and selecting M-l in total from all the weighting coefficients of the rest second base vectors 0 The value of M being configured by the base station or being
Wherein delta M Is a preset threshold value; feeding back its selected subset using one of the following sub-ways: sub-mode D-1: the coefficients it selects are indicated using a bitmap of 2L · K size; sub-mode D-2: use of
Indicating the selected optimal second basis vectors for reuse
The remaining M-l indicating its selection 0 A coefficient;
alternatively, the mode E: sequencing the K second base vectors, and respectively selecting l from the weighting coefficients of the strong second base vectors to the weak second base vectors 0 ,l 0 -1，...,l 0 -M +1 coefficients, the coefficients of which are selected being indicated using a bitmap of 2L · K size.
Wherein, the fourth mode includes:
mode F: in all weighting coefficients of the first basis vector in two groups, each feedback
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold; by means of a bit map or
Indicating the selected coefficients;
alternatively, the mode G: within two groups, the rootFeedback on the priority of the first base vector and indicating its selected coefficients using a 2L · K sized bitmap, comprising: sub-mode G-1: selecting an optimal first base vector in each of the two groups, and selecting l from the weighting coefficients of the two optimal first base vectors 0 Coefficients, each of which is selected among all the weighting coefficients of the remaining first basis vectors in the two groups
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold; or sub-mode G-2: selecting an optimal first base vector in each of the two groups, wherein each of the weighting coefficients of the two optimal first base vectors 0 Coefficients, each of which is selected again from the weighting coefficients of the remaining first basis vectors in the two groups 1 Coefficient of (a) l 1 ＜l 0 ，；
Alternatively, the mode H: within the two packets, the coefficients fed back according to the priority of the second base vector and whose selection is indicated using a bitmap of 2L · K size include: sublevel H-1: selecting an optimal second base vector in each of two groups, and selecting l from weighting coefficients of the optimal second base vector in the 1 st group 0 Coefficient, selecting l from the weighting coefficients of the optimal second basis vector in the 2 nd group 0 Coefficients, each of which is selected among all the weighting coefficients of the remaining second basis vectors in the two groups
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold; or sublay H-2: selecting an optimal second base vector in each of the two groups, and selecting l from the weighting coefficients of the optimal second base vectors in the 1 st group 0 Coefficient, selecting/from weighting coefficients of optimal second base vector in 2 nd group 0 Coefficients, each of which is selected again from the weighting coefficients of the remaining second basis vectors in the two groups 1 Coefficient of (a) l 1 ＜l 0 。
Wherein, mode five includes:
mode I: dividing the second coefficient into group number combinations, and the terminal selects the most suitable combination for feedback
Indicating a selected combination thereof;
alternatively, the mode J: dividing the second coefficients into group number combinations, selecting 1 most suitable combination, and selecting l-1 combinations from the rest, using log 2 GroupNumberbits indicate the most appropriate combination to choose, using
The remaining combinations are indicated.
Before the terminal feeds back the precoding matrix information, the method further comprises the following steps:
receiving a first signaling sent by a base station; the first signaling comprises a first amplitude feedback penalty factor configured by the base station and a first base vector indicating that power limitation needs to be performed, and is used for performing power limitation on a weighting coefficient of the first base vector needing to be performed with power limitation;
after the amplitude of the weighting coefficient of the first base vector needing to be subjected to power limitation fed back by the terminal is quantized, the weighting coefficient cannot exceed a first amplitude feedback penalty factor configured by the base station, or after the amplitude of the weighting coefficient of the first base vector needing to be subjected to power limitation is multiplied by a first amplitude feedback penalty factor configured by the base station, the quantization is carried out;
and/or receiving a second signaling sent by the base station; the second signaling comprises a second amplitude feedback penalty factor configured by the base station and a second base vector indicating that power limitation needs to be performed, and is used for performing power limitation on a weighting coefficient of the second base vector needing power limitation;
and after the amplitude of the weighting coefficient of the second base vector needing to be subjected to power limitation fed back by the terminal is quantized, the weighting coefficient cannot exceed a second amplitude feedback penalty factor configured by the base station, or after the amplitude of the weighting coefficient of the second base vector needing to be subjected to power limitation is multiplied by a second amplitude feedback penalty factor configured by the base station, the second amplitude feedback penalty factor is quantized.
Wherein the feeding back the precoding matrix information includes:
dynamically reducing the number of the fed-back second base vectors when the feedback resources are insufficient and the selected second base vector number K is configured by the terminal;
or when the selected second base vector number K is configured by the base station, if the feedback resources are sufficient, uploading all parameters configured by the base station, otherwise, selecting one of the following modes:
when precoding matrix information is fed back according to the mode one, if feedback resources are insufficient, dynamically notifying the selected coefficients through a bit map based on a certain criterion until the maximum feedback resources are reached;
or when precoding matrix information is fed back according to the mode A or the mode C included in the mode II, if the feedback resource is insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal first base vector, and then the terminal dynamically informs the selected coefficient through a bit map based on a certain criterion until the maximum feedback resource is reached; when the mode B included in the mode II feeds back precoding matrix information and uses the sub-mode B-1 to feed back subset indication, if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal first base vector, and then the terminal dynamically informs the selected coefficient through a bit map based on a certain criterion until the maximum feedback resources are reached; when precoding matrix information is fed back according to the mode B included in the mode II and subset indication is fed back by using the sub-mode B-2, if feedback resources are insufficient, the terminal only feeds back the weighting coefficient of the optimal first base vector;
or when precoding matrix information is fed back according to the mode D included in the mode III and a subset is fed back for indication by using the sub-mode D-1, if the feedback resource is insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal second base vector, and then the terminal dynamically informs the selected coefficient through a bitmap based on a certain criterion until the maximum feedback resource is reached; when precoding matrix information is fed back according to the mode D included in the mode III and subset indication is fed back by using the sub-mode D-2, if feedback resources are insufficient, the terminal only feeds back the weighting coefficient of the optimal second base vector; when precoding matrix information is fed back according to the mode E included in the mode III, if the feedback resource is insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal second base vector, and then the terminal dynamically informs the selected coefficient through a bit map based on a certain criterion until the maximum feedback resource is reached;
or when feeding back precoding matrix information according to the mode F included in the mode four, if the feedback resource is insufficient, dynamically notifying the selected coefficient through a bit map until the maximum feedback resource is reached; when precoding matrix information is fed back according to the sub-mode G-1 or the sub-mode G-2 included in the mode G included in the mode IV, if the feedback resources are insufficient, the weighting coefficient of the optimal first base vector in the first group is fed back preferentially, then the weighting coefficient of the optimal first base vector in the second group is fed back, and then the selected coefficient is informed dynamically through a bitmap until the maximum feedback resources are reached; when precoding matrix information is fed back according to the sub-mode H-1 or the sub-mode H-2 included in the mode H included in the mode IV, if the feedback resources are insufficient, the weighting coefficient of the optimal second base vector in the first group is fed back preferentially, then the weighting coefficient of the optimal second base vector in the second group is fed back, and then the selected coefficient is informed dynamically through a bitmap until the maximum feedback resources are reached;
or when precoding matrix information is fed back according to the mode I included in the mode five and a selected packet is fed back by using a bit map, if the feedback resource is insufficient, the base station is dynamically informed of the selected packet according to the bit map based on a certain criterion until the maximum feedback resource is reached; and when precoding matrix information is fed back according to the mode J included by the mode five, if the feedback resource is insufficient, preferentially feeding back a weighting coefficient corresponding to the optimal grouping.
Second embodiment
Fig. 2 is a schematic flow chart of a CSI feedback method according to a second embodiment of the present invention, as shown in fig. 2, the method includes:
the precoding vectors in the feedback precoding sub-band are linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
Before the base station receives the precoding matrix information fed back by the terminal, the method further comprises the following steps:
and the base station configures a frequency domain range needing to feed back the CSI and sends the frequency domain range to the terminal, so that the terminal determines a precoding sub-band needing to feed back precoding information according to the frequency domain range of the CSI.
Wherein the frequency domain range of the configured CSI comprises: the method comprises the steps that a precoding sub-band needing to feed back CSI, or a precoding sub-band needing to comb-feed back CSI and the sparsity degree, or a precoding sub-band needing not to feed back CSI.
Before the base station receives the precoding matrix information fed back by the terminal, the method further comprises the following steps:
the base station configures a feedback mode and a feedback subset indication of a second coefficient and sends the feedback mode and the feedback subset indication to the terminal, so that the terminal can feed back the second coefficient according to the feedback mode and the feedback subset indication of the second coefficient;
the feedback mode of the second coefficient comprises one of the following modes:
the first method is as follows: feeding back a second coefficient according to the priority level of the amplitude of the second coefficient;
the second method comprises the following steps: feeding back a second coefficient by taking the first base vector as priority;
the third method comprises the following steps: feeding back a second coefficient by taking the second base vector as priority;
the method is as follows: dividing the first base vectors into two groups, and dividing the 1 st to the L th first base vectors, namely W 1 As a first group, the L +1 to 2L first base vectors, i.e., W 1 As a second group, feeding back a second coefficient according to the priority inside the packet;
the fifth mode is as follows: grouping the second coefficients, and feeding back the second coefficients according to the priority of the grouping;
the feedback subset indicates a manner for instructing the terminal to feed back the subset of the second coefficients.
Before the base station receives the precoding matrix information fed back by the terminal, the method further includes:
sending a first signaling and/or a second signaling to a terminal;
the first signaling comprises a first amplitude feedback penalty factor configured by the base station and a first base vector indicating that power limitation needs to be performed, and is used for performing power limitation on a weighting coefficient of the first base vector needing to be performed with the power limitation; the second signaling comprises a second amplitude feedback penalty factor configured by the base station and a second base vector indicating that power limitation needs to be performed, and is used for performing power limitation on the weighting coefficient of the second base vector needing to be performed with the power limitation.
Wherein the content of the first and second substances,
the first amplitude feedback penalty factor is
Or
Or, the second amplitude feedback penalty factor is
Or
The technical solutions provided by the first and second embodiments of the present invention are explained in detail by two specific examples.
Example one
The embodiment of the invention provides a method for compressing the channel coefficients of the space domain and the frequency domain for CSI feedback, namely the precoding of a certain layer on all precoding sub-bands can be represented again in the following form,
for the pre-coding vector of the layer, all the first coefficients of all the pre-coding sub-bands form a matrix W 2 。W 2 Dimension of 2L multiplied by N s ，N s Representing the number of pre-coded sub-bands
And S represents a frequency domain unit of precoding fed back by the terminal, and can be adjusted according to the feedback precision. S is called the precoding sub-band size, and it can consist of 1 or more RBs, N s Called the number of pre-coded sub-bands; the 2L elements of each column thereof, corresponding to a subband, represent coefficients of the linear superposition of the 2L first basis vectors. The CSI feedback frequency band refers to a frequency domain range in which the base station needs to feed back CSI, and the number of RBs included in the frequency domain range is RBNum. The precoding sub-band is a frequency domain unit, and the number of the RBs contained in the precoding sub-band can be determined by the configuration of the base station or the number of the RBs in the feedback sub-band and the used second base vector number, namely the number of the RBs contained in the precoding sub-band is
RBNum is the number of RBs contained in the CSI feedback frequency band, and K is the number of second base vectors used by the CSI feedback frequency band.
W 1 Comprising 2L first basis vectors, W 1 Dimension N t X 2L, of the form:
wherein, b 0 ,b 1 ,…,b L-1 Is composed of a set of orthogonal DFT (Discrete Fourier transform) vectors or the kronecker product of DFT vectors, and the dimension of the kronecker product is
N t Indicating the number of ports of the CSI-RS.
Wherein the frequency domain compression matrix W 3 ＝[w 0 w 1 … w K-1 ]And represents K basis vectors selected from the DFT matrix or the oversampled DFT matrix, which is referred to as a second basis vector. Dimension of DFT matrix is N s ×N s ；
Wherein said L may be one of: 2. 3,4, 5 and 6. The K may be one of: 1. 2, \8230, 8230, N s I.e. the value that Kmax can take is the number N of precoding subbands s 。
Wherein, the column vector of the DFT matrix is,
wherein m = m 0 ,m 0 +O f ,m 0 +2O f ,…,m 0 +(N s -1)O f ；(m 0 ＝1,2,…,O f )，O f The value of the oversampling factor is 1,2, 4, 8, etc.
Wherein the content of the first and second substances,
dimension 2L K, denotes W 2 The matrix after frequency domain compression represents the weighting coefficient of the second base vector, which is called the second coefficient. In this embodiment, the weighting factor of the ith first base vector, except for the mode C-4, refers to
K coefficients for row i; the weighting coefficient of the jth second base vector means
2L coefficients of j columns. In mode C-4, the weighting factor of the jth second basis vector in the first grouping, i.e.
The j th column and the L coefficients from the 1 st row to the L th row; within the second group, the weighting coefficients of the jth second base vector, i.e.
And (3) L coefficients of the jth column and the L +1 to 2L rows.
On the basis of the new subband precoding representation, fig. 3 is a schematic flow chart of a CSI feedback method according to an embodiment of the present invention, and as shown in fig. 3, the method includes:
wherein the configuration information comprises at least one of:
the base station configures a frequency domain range needing to feed back the CSI, a feedback mode and a feedback subset indication of a configured second coefficient, a configured first amplitude feedback penalty factor, a first base vector indicating that power limitation needs to be performed, a configured second amplitude feedback penalty factor, a second base vector indicating that power limitation needs to be performed and other information.
Wherein the frequency domain range of the CSI comprises: the method comprises the steps that a precoding sub-band needing to feed back CSI, or a precoding sub-band needing to comb-feed back CSI and the sparsity degree, or a precoding sub-band needing not to feed back CSI.
Feeding back a precoding vector in a precoding subband, wherein the precoding vector is linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
Wherein the second basis vectors represent K DFT basis vectors selected from a DFT matrix or an oversampled DFT matrix having an oversampling factor O f The value of (a) is one of the following: 1. 2, 4 and 8.
The second base vector is a DFT base vector, and the second base vector may be partially corrected according to actual needs, for example, the second base vector, that is, W 3 The selection of the medium basis vector needs to consider some special cases, and more specifically, includes the following special cases and solutions:
mode A-1: the base station may not need the terminal to upload CSI of all precoded subbands, and the precoded subbands configured by the base station and needing to upload CSI may be discontinuous, so that the DFT base vector needs to be corrected. Specifically, the following sub-modes are improved:
subformulae A-1-1: the base station adopts comb configuration to pre-coding sub-bands needing to upload CSI, namely the base station designates the S < th > S 0 +Δ,S 0 +2Δ,S 0 +3 Δ, \8230; (Δ =1,2,3,4 \8230; indicating the sparsity of the configuration) CSI of the precoded subbands requires feedback, in which case the DFT matrix can be modified in two ways:
sub-mode A-1-1-1: the base station configures a larger oversampling factor by adopting an oversampled DFT matrix, increases the number of selectable DFT matrixes, and essentially increases the phase difference of adjacent elements of a DFT base vector to match the phase offset increase caused by the loss of partial precoding sub-bands;
subformulae A-1-1-2: truncating part of the DFT matrix, i.e. only the S-th basis vector is retained 0 +Δ,S 0 +2Δ,S 0 +3 delta, 8230and elements. At this time, different base vectors of the DFT matrix are still orthogonal, but the phase difference between adjacent elements of the same base vector becomes large, which can match the increase of phase offset caused by the deletion of part of precoding subbands;
sub-mode A-1-2: the base station may only configure a part of subbands and does not need to upload CSI, and a specific example is that the base station configures the sth i Each precoded subband does not need to report CSI. Then, when performing frequency domain compression, the S-th of DFT base vector can be cut off i And (4) elements to adapt to the condition that partial pre-coding sub-bands are missing.
Mode B-1: the DFT base vector is referenced to the first precoded subband, i.e. the first element of the DFT base vector is 1. The accumulated quantization error can be reduced by changing the reference pre-coded sub-band to be located in the middle of all pre-coded sub-bands. Specifically, the phase rotation is performed on the original DFT basis vector as follows,
where another important issue for the frequency domain compression feedback method is the second coefficient, i.e. the
Is sent to the mobile station. According to the magnitude of the second coefficient, the first basis vector, the second basis vector, the priority of grouping the first basis vectors or the combination of the first and second basis vectors,
the 2 L.K elements can be selected to be partial subsets or all feedbacks, and different subsets can also feedback differentTo improve performance. Furthermore, the base station and the terminal need to agree on in what way the terminal-selected subset needs to be informed to the base station, i.e. the feedback subset indication of the second coefficients. The specific feedback mode and the subset indication mode may be one of the following modes:
mode C-1: feeding back a second coefficient according to the priority level of the amplitude of the second coefficient;
wherein, the part with larger amplitude of the second coefficient can reflect the real channel characteristics more usually. In a specific example, the terminal ranks the amplitudes of the second coefficients from large to small, selects a part of coefficients from large to small until the ratio of the sum of the powers of the part of coefficients to the total power of the second coefficients is not less than δ, and feeds back the selected part of coefficients. Where δ is a threshold value, typical values may be 0.90, 0.95, 0.99, etc. The terminal indicates its selected coefficients using a bitmap of 2L · K size.
Mode C-2: selecting coefficients from the first basis vector;
the first base vector corresponds to a beam in space, and usually, the received signals are concentrated in some specific beam directions, so that the priority and the feedback accuracy of the specific beam are improved, and the system performance can be improved. Specifically, the second coefficient is fed back by taking the first base vector as the priority, and one of the following sub-modes can be selected:
sub-mode C-2-1: the terminal selects the optimal first base vector based on a certain criterion (such as the maximum power sum of K coefficients corresponding to a certain first base vector), and then K weighting coefficients (corresponding to the K weighting coefficients) of the optimal first base vector
A certain line of) in the feedback l 0 A coefficient; the quantization accuracy of the weighting coefficients of this first basis vector, such as quantization of the amplitude and phase to (3, 4) bits or (4, 4) bits; selecting l from the K weighting coefficients of the remaining first basis vectors 1 (l 1 ＜l 0 ) The coefficients, magnitude and phase are quantized to (2, 3) bits or (3, 3) bits, where the magnitude can be quantized directly or according to the magnitude of the optimal first basis vectorThe degrees are differentially quantized. The terminal uses the bitmap with the size of 2 L.K to indicate the selected coefficient, the base station can know the feedback subset and the first base vector with the optimal feedback according to the bitmap information fed back by the terminal, and further can calculate the total cost for feeding back the second coefficient according to the configured quantization precision.
Subform C-2-2: the terminal selects an optimal first base vector based on a certain criterion, and then the optimal first base vector feeds back l in K weighting coefficients 0 The quantization precision of the weighting coefficients of the optimal first basis vector can be increased appropriately, such as quantization of the amplitude and phase to (3, 4) bits or (4, 4) bits; the total M-l is selected among all the weighting coefficients of the rest of the first base vectors except the optimal first base vector 0 The value of M may be configured by the base station or be
Wherein delta M Is a preset threshold value; the quantization precision of the amplitude and the phase is (2, 3) bits or (3, 3) bits, wherein the amplitude can be directly quantized or differentially quantized according to the amplitude of the optimal first base vector. The part of the second coefficient that the terminal indicates to feed back may be implemented by one of the following sub-ways:
and in the sub-mode C-2-2-1, the terminal indicates the selected coefficient by using a bitmap with the size of 2 L.K, the base station can know the fed-back subset and the optimal first base vector according to the bitmap information fed back by the terminal, and further can calculate the total overhead of feeding back the second coefficient according to the configured quantization precision. Note that the number of weighting coefficients chosen at the non-optimal first basis vectors must be less than l 0 Otherwise, the base station cannot implicitly know the position of the optimal first base vector through a bit map;
sub-mode C-2-2-2 terminal usage
Indicating the selected optimal first basis vector for reuse
Remaining M-l indicating its selection 0 The base station can further calculate the total cost for feeding back the second coefficient according to the configured quantization precision;
in the sub-mode C-2-3, the terminal sequences the strength of 2L wave beams based on a certain criterion, and the corresponding wave beams from strength to strength are respectively selected to be L 0 ,l 0 -1，...,l 0 And the base station can configure different feedback accuracies according to different intensities of beams of the base station by the M +1 coefficients. The terminal uses the bitmap with the size of 2 L.K to indicate the selected coefficient, the base station can know the sequencing condition of the fed-back subset and the first base vector according to the bitmap information fed back by the terminal, and further can calculate the total overhead of feeding back the second coefficient according to the configured quantization precision.
Mode C-3: from a second base vector perspective;
wherein, a second base vector corresponds to a delay path of the channel, if the feedback precision of a certain strongest delay path is higher, the system performance can be improved. Specifically, the second coefficient is fed back by taking the second base vector as the priority, and one of the following sub-modes can be selected:
sub-mode C-3-1: the terminal selects an optimal second base vector based on a certain criterion (for example, the power sum of 2L coefficients corresponding to a certain second base vector is maximum), and the optimal 2L weighting coefficients of the second base vector ((corresponding to 2L weighting coefficients)
Column of (d)) in the feedback l 0 A coefficient. The quantization precision of the weighting coefficients of the basis vector can be increased appropriately, for example, the quantization precision of the amplitude and phase is (3, 4) bits or (4, 4) bits; of all the weighting coefficients of the remaining second basis vectors, the (M-l) with the largest magnitude coefficient is selected again in total 0 ) The value of M may be configured by the base station or be
Wherein delta M Is a preset threshold; the quantization precision of the amplitude and the phase is (2, 3) bits or (3, 3) bits, wherein the amplitude can be directly quantized or rootedAnd carrying out differential quantization according to the amplitude of the optimal second base vector. The part of the second coefficients that the terminal indicates to feed back may be implemented by one of the following sub-manners:
subformulae C-3-1-1: the terminal uses the bitmap with the size of 2 L.K to indicate the selected coefficient, the base station can know the feedback subset and the optimal second base vector according to the bitmap information fed back by the terminal, and further can calculate the total cost for feeding back the second coefficient according to the configured quantization precision. Note that the number of coefficients chosen at the non-optimal second basis vector must be less than l 0 Otherwise, the base station cannot implicitly know the position of the optimal second base vector through the bitmap;
sub-mode C-3-1-2 terminal usage
Indicating the selected optimal second basis vectors for reuse
The remaining M-l indicating its selection 0 And the base station can further calculate the total cost for feeding back the second coefficient according to the configured quantization precision.
Subform C-3-2: the terminal sequences the strength of the K second base vectors based on a certain criterion, and l are respectively selected from the weighting coefficients of the corresponding second base vectors from strength to strength 0 ,l 0 -1，...,l 0 And M +1 coefficients, and the base station can configure different amplitude and phase quantization precisions according to different strengths of second base vectors. The terminal uses the bitmap with the size of 2 L.K to indicate the selected coefficient, the base station can know the sequencing conditions of the fed-back subset and the second base vector according to the bitmap information fed back by the terminal, and further, the total overhead for feeding back the second coefficient can be calculated according to the configured quantization precision.
Mode C-4: dividing the first base vectors into two groups, and dividing the 1 st to Lth first base vectors, namely W 1 As a first group, the L +1 to 2L first base vectors, i.e., W 1 As a second group, according to the internal advantages of the packetThe first stage feeds back a second coefficient;
wherein the L first basis vectors are pairs 1 to 1
Precoding of one CSI-RS port, and another L first base vectors being pair
To N t Precoding of individual CSI-RS ports. Selected in a group according to a certain rule
And improving the feedback accuracy will improve the system performance. Specifically, at least one of the following sub-modes may be selected:
sub-mode C-4-1: the terminal includes weighting coefficients (i.e. the weighting coefficients of the first basis vectors in the first set) based on a certain criterion (e.g. magnitude ordering of the second coefficients)
1 to L of row) select
The number of the coefficients is such that,
may be configured by the base station or be
Wherein delta M Is a preset threshold value; weighting coefficients of first basis vectors included in the second group (i.e. weighting coefficients of second basis vectors included in the second group)
Lines L +1 to 2L) of (c) a reselection
A coefficient. The terminal uses a bitmap of 2 L.K size or
Indicating the coefficients it selects.
And in the sub-mode C-4-2, the terminal selects an optimal first base vector from the two groups of first base vectors based on a certain criterion. The corresponding coefficients of the two optimal first basis vectors may feed back more elements and increase the quantization accuracy. Specifically, one of the following sub-manners may be taken.
Sub-mode C-4-2-1: the terminal selects an optimal first base vector from the two groups of first base vectors based on a certain criterion. Each feedback l in the weighting coefficients of the two optimal first basis vectors 0 Coefficients that can be quantized with an appropriate increase in quantization accuracy, such as (3, 4) bits or (4, 4) bits in amplitude and phase. Of all the weighting coefficients of the remaining first basis vectors in each group, a total of reselections
The number of the coefficients is such that,
may be configured by the base station or be
Wherein delta M Is a preset threshold value; the quantization precision of the amplitude and the phase is (2, 3) bits or (3, 3) bits, wherein the amplitude can be directly quantized or differentially quantized according to the amplitudes of the two optimal first basis vectors. The terminal uses the bitmap with the size of 2 L.K to indicate the selected coefficient, the base station can know the optimal first base vector in the feedback subset and the two groups according to the bitmap information fed back by the terminal, and further, the total cost for feeding back the second coefficient can be calculated according to the configured quantization precision. Note that the number of coefficients chosen at the non-optimal first basis vector must be less than l 0 Otherwise, the base station cannot implicitly know the position of the optimal first base vector through the bitmap.
Subformulae C-4-2-2: the terminal selects an optimal first base vector from the two groups of first base vectors based on a certain criterion.Each feedback l in the weighting coefficients of the two optimal first basis vectors 0 And coefficients that can be quantized with an appropriate increase in quantization accuracy, such as amplitude and phase quantization to (3, 4) bits or (4, 4) bits. Two groups respectively select l again from the weighting coefficients of the rest first base vectors 1 (l 1 ＜l 0 ) Coefficient (i.e. the
Each row of (1) 1 Coefficients) with an amplitude and phase quantization precision of (2, 3) bits or (3, 3) bits, wherein the amplitude can be quantized directly or quantized differentially according to the amplitudes of the two optimal first basis vectors. The terminal uses the bitmap with the size of 2 L.K to indicate the selected coefficient, the base station can know the feedback subset and the respectively optimal first base vector in the two groups according to the bitmap information fed back by the terminal, and further can calculate the total cost for feeding back the second coefficient according to the configured quantization precision.
And a sub-mode C-4-3 is that the terminal selects an optimal second base vector from the two groups of first base vectors based on a certain criterion. The corresponding coefficients of the two second basis vectors can feed back more elements and increase the quantization accuracy. Specifically, one of the following sub-approaches may be taken:
sub-mode C-4-3-1: the terminal selects an optimal second base vector from the two groups of first base vectors based on a certain criterion. Selecting l from weighting coefficients of optimal second base vectors in 1 st group 0 Coefficient, selecting l from the weighting coefficients of the optimal second basis vector in the 2 nd group 0 And coefficients that can be quantized with an appropriate increase in quantization accuracy, such as amplitude and phase quantization to (3, 4) bits or (4, 4) bits. Of all the weighting factors of the remaining second basis vectors in each group, a total of reselections
The number of the coefficients is such that,
can be configured by the base station or be
Wherein delta M Is a preset threshold value; the quantization precision of the amplitude and the phase is (2, 3) bits or (3, 3) bits, wherein the amplitude can be directly quantized or differentially quantized according to the amplitudes of the two optimal second base vectors. The terminal uses the bitmap with the size of 2 L.K to indicate the selected coefficient, the base station can know the optimal second base vector in the feedback subset and the two groups according to the bitmap information fed back by the terminal, and further, the total cost for feeding back the second coefficient can be calculated according to the configured quantization precision. Note that the number of coefficients chosen at the non-optimal first basis vector must be less than l 0 Otherwise, the base station cannot implicitly know the position of the optimal second base vector through the bitmap.
Subformulae C-4-3-2: the terminal selects an optimal second base vector from the two groups of first base vectors based on a certain criterion. Selecting/from weighting coefficients of optimal second base vectors in 1 st group 0 Coefficient, selecting/from weighting coefficients of optimal second base vector in 2 nd group 0 And coefficients that can be quantized with an appropriate increase in quantization accuracy, such as amplitude and phase quantization to (3, 4) bits or (4, 4) bits. Two groups respectively select l again from the weighting coefficients of the rest second base vectors 1 (l 1 ＜l 0 ) Coefficient (i.e. the
Each column of (1) 1 Coefficients) with a quantization precision of (2, 3) bits or (3, 3) bits, wherein the amplitude can be directly quantized or differentially quantized according to the amplitudes of the two optimal second basis vectors. The terminal uses the bitmap with the size of 2 L.K to indicate the selected coefficient, the base station can know the feedback subset and the respectively optimal second base vector in the two groups according to the bitmap information fed back by the terminal, and further can calculate the total cost for feeding back the second coefficient according to the configured quantization precision.
Mode C-5: grouping the second coefficient, and feeding back according to the priority of the grouping;
the beams and corresponding delays of the received signals are relatively concentrated, as embodied in
The part with larger amplitude of (1) will be distributed in the second coefficient in a concentrated way
A certain position of (a). Thus, can be used for
Grouping is carried out, the terminal feeds back the most appropriate combination, the quantization precision is increased, and the system performance can be improved. Specifically, at least one of the following sub-modes may be selected:
mode C-5-1: grouping according to the size of L and K, dividing into
A combination of wherein L s And K s And respectively representing the grouping granularity of the first base vector and the second base vector, wherein the grouping granularity can be selected according to the values of L and K and the feedback precision. The terminal selects the most suitable combination for feedback based on a certain criterion. Terminal use
Bit map or
And indicating the selected combination, wherein the base station can calculate the total overhead of feeding back the second coefficient according to the combination selected by the terminal and further according to the configured quantization precision.
Mode C-5-2: grouping according to the size of L and K, dividing into
A combination of wherein L s And K s Respectively representing the grouping granularity of the first base vector and the second base vector, wherein the grouping granularity can be carried out according to the values of L and K and the feedback precisionAnd (4) selecting. The terminal selects 1 most suitable combination based on a certain criterion, and the coefficients in the combination can appropriately increase the quantization precision, such as quantization of amplitude and phase to (3, 4) bits or (4, 4) bits. The terminal selects (M-1) combinations, and the quantization precision of the coefficients in the combinations can be (2, 3) bits or (3, 3) bits. Terminal use
Indicates the optimal combination of its choices, and in addition needs
Indicating the selected other combination, further based on the configured quantization precision, the total cost of feeding back the second coefficient may be calculated.
In an actual communication system, the first base vector corresponds to beams in space, and since the beams have directivity, some beams in the signal of one terminal have too large signal strength, which will cause interference to other users. Therefore, the base station typically limits the particular beam, such as limiting the wideband amplitude power of the particular beam. In addition, the base station can limit the unnecessary second base vector according to the reciprocity of the TDD system, and reduce the multipath interference of the signal. Specifically, the following ways may be adopted:
mode D-1: all the optional first base vectors are grouped, namely the base station selects one group, if the beam fed back by the terminal is positioned in the group configured by the base station, the power limitation is carried out on the amplitude of the sub-band, namely the power limitation is carried out on the amplitude of the sub-band
Certain rows of (corresponding to some beams) are power limited. For example, if the ith first base vector fed back by the terminal happens to be the first base vector that the base station needs to perform power limitation, one of the following two sub-modes can be selected:
sub-mode D-1-1:
quantization of the amplitude of the i, i + L th line of (1)The first amplitude feedback penalty factor configured by the base station can not be exceeded later, and the first amplitude feedback penalty factor configured by the base station is
Or alternatively
Subformulae D-1-2:
the integral amplitude of the ith and i + L rows is multiplied by a certain first amplitude feedback penalty factor and then is quantized, and the first amplitude feedback penalty factor can be taken as
Or
Mode D-2: in the TDD system, based on the reciprocity principle, a base station can reciprocity to a downlink channel through an uplink channel estimated by an uplink reference signal. Therefore, the base station can roughly estimate the time delay situation of the downlink channel. And a second base vector essentially reflects a delay path, and the base station can avoid interference caused by some unnecessary delay components by limiting the second base vector selected by the terminal. Specifically, this can be achieved by one of the following sub-ways:
subformulae D-2-1: grouping all the optional second base vectors, selecting a group by the base station through high-layer parameter configuration, and if one second base vector selected by the terminal is overlapped with the group configured by the base station, performing power limitation through the following two sub-modes:
sub-mode D-2-1-1: all the weighting coefficients corresponding to the second base vector cannot exceed a second amplitude feedback penalty factor configured by the base station after amplitude quantization, and the second amplitude feedback penalty factor configurable by the base station is
Or
Sub-mode D-2-1-2: all weighting coefficients of the second base vector are quantized after the amplitude is integrally multiplied by a certain second amplitude feedback penalty factor, and the second amplitude feedback penalty factor can be taken
Or
It is noted that the above-mentioned ways D-1 and D-2 are not mutually exclusive and that both can be used in combination, while avoiding interference and reducing unnecessary feedback of the second basis vectors.
The terminal estimates a downlink Channel by measuring the CSI-RS, estimates interference by using other reference signals, and feeds back RI (Rank indicator), CQI (Channel quality indicator), and PMI (Precoding matrix indicator) according to a base station indicator according to a Channel condition. Because the base station cannot predict the RI fed back by the terminal or the base station triggers multiple CSI reports at the same time, there is a possibility that the resource for transmitting CSI in uplink is insufficient. Therefore, it is necessary to define which part of the resources should be fed back preferentially when the feedback resources are insufficient. Depending on the way of improvement of the second basis vector and the way of feedback of the second coefficient and the various ways of indication of the feedback subset, one of the following ways may be selected:
mode E-1: the selected second base vector number K is fed back by the terminal, and if the fed-back CSI resource is insufficient, the terminal can dynamically reduce the fed-back second base vector number, thereby reducing the feedback overhead.
Mode E-2: the selected second number of basis vectors K is configured by the base station, and if the fed back CSI resource is insufficient, one of the following sub-modes may be specifically selected:
and the sub-mode E-2-1 feeds back the CSI according to the mode C-1, and if the feedback resources are sufficient, the parameters configured by all the base stations are uploaded. If the feedback resources are not sufficient, then the terminal can dynamically inform its selected coefficients through a bitmap based on certain criteria until the maximum feedback resources are reached.
Sub-mode E-2-2: and feeding back CSI in a mode C-2, and uploading all parameters configured by the base station if the feedback resources are sufficient. Specifically, when the CSI is fed back according to the sub-mode C-2-1 and the sub-mode C-2-3, if the feedback resources are insufficient, the terminal preferentially feeds back the coefficient corresponding to the optimal first base vector, and then the terminal can dynamically inform the selected coefficient through a bitmap based on a certain criterion until the maximum feedback resources are reached; feeding back CSI according to the sub-mode C-2-2, and feeding back subset indication according to the sub-mode C-2-2-1, if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient corresponding to the optimal first base vector, and then the terminal can dynamically inform the selected coefficient through a bitmap based on a certain criterion until the maximum feedback resources are reached; and feeding back CSI according to the sub-mode C-2-2, and feeding back the subset indication according to the sub-mode C-2-2, wherein if the feedback resources are insufficient, the terminal only feeds back the weighting coefficient of the optimal first base vector.
Sub-mode E-2-3: and feeding back CSI according to the mode C-3, and uploading all parameters configured by the base station if the feedback resources are sufficient. Specifically, the CSI is fed back according to the sub-mode C-3-1, and the subset is fed back according to the sub-mode C-3-1-1 to indicate, if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal second base vector, and then the terminal can dynamically inform the selected coefficient through a bitmap based on a certain criterion until the maximum feedback resources are reached; feeding back CSI according to the sub-mode C-3-1, feeding back subset indication according to the sub-mode C-3-1-2, and if the feedback resources are insufficient, feeding back the weighting coefficient of the optimal second base vector by the terminal; when the CSI is fed back according to the sub-mode C-3-2, if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal second base vector, and then the terminal may dynamically notify the selected coefficient through a bitmap based on a certain criterion until the maximum feedback resources are reached.
Sub-mode E-2-4: and feeding back CSI according to the mode C-4, and uploading all parameters configured by the base station if the feedback resources are sufficient.
Specifically, CSI is fed back according to the sub-mode C-4-1, the selected coefficient is indicated according to the bit map mode, and if the feedback resources are insufficient, the selected coefficient is dynamically informed through the bit map until the maximum feedback resources are reached; feeding back CSI according to the sub-mode C-4-2-1 and the sub-mode C-4-2-2, if the feedback resources are insufficient, the terminal feeds back the weighting coefficient of the optimal first base vector in the first grouping preferentially, then feeds back the weighting coefficient of the optimal first base vector on the second grouping, and then the terminal can dynamically inform the selected coefficient through a bitmap based on a certain criterion until the maximum feedback resources are reached; and feeding back CSI according to the sub-mode C-4-3-1 and the sub-mode C-4-3-2, if the feedback resources are insufficient, the terminal feeds back the weighting coefficient of the optimal second base vector in the first group preferentially and feeds back the weighting coefficient of the optimal second base vector in the second group secondly, and then the terminal can dynamically inform the selected coefficient through a bitmap based on a certain criterion until the maximum feedback resources are reached.
Sub-mode E-2-5: feeding back CSI in a mode of C-5-1, feeding back a selected packet by using a bit map, and if the feedback resources are insufficient, dynamically informing the base station of the selected packet by the terminal according to the bit map based on a certain criterion until the maximum feedback resources are reached; and feeding back CSI according to the mode C-5-2, and uploading all parameters configured by the base station if the feedback resources are sufficient. And if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient corresponding to the optimal grouping.
It should be noted that the above scheme is applicable to CSI of each layer fed back by the terminal.
Example two
On the basis of the precoding representation of the new subband in the third embodiment, fig. 4 is a schematic flow chart of the CSI feedback method provided in the second embodiment of the present invention, and as shown in fig. 4, the method includes:
wherein the frequency domain range of the configured CSI comprises: the method comprises the steps that a precoding sub-band needing to feed back CSI, or a precoding sub-band needing to comb-feed back CSI and the sparsity degree, or a precoding sub-band needing not to feed back CSI.
wherein the feedback mode of the second coefficient comprises one of the following modes:
the first method is as follows: feeding back a second coefficient according to the amplitude of the second coefficient as the priority;
the second method comprises the following steps: feeding back a second coefficient by taking the first base vector as priority
The third method comprises the following steps: feeding back a second coefficient by taking the second base vector as priority;
the method four comprises the following steps: dividing the first base vectors into two groups, and dividing the 1 st to the L th first base vectors, namely W 1 As a first group, the L +1 to 2L first base vectors, i.e., W 1 As a second group, feeding back a second coefficient according to the priority inside the packet;
the fifth mode is as follows: and grouping the second coefficients, and feeding back the second coefficients according to the priority of the grouping.
Wherein the feedback subset indicates a manner for instructing the terminal to feedback the subset of the second coefficients.
And step 403, the terminal indicates to feed back precoding matrix information according to the frequency domain range of the CSI to be fed back configured by the base station, the feedback mode of the second coefficient, and the feedback subset.
The precoding matrix information comprises first base vector information, second base vector information, and amplitude and phase information of a second coefficient.
The precoding vectors in the feedback precoding sub-band are linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
The CSI feedback band refers to a frequency domain range in which the base station needs to feed back CSI. .
The precoding sub-band is a frequency domain unit, and the number of the RBs contained in the precoding sub-band is determined by the number of the RBs configured by the base station or contained in the CSI feedback frequency band and the number of the second base vectors used, namely the number of the RBs is
RBNum is the number of RBs contained in the CSI feedback band, and K is the number of second base vectors used by the CSI feedback band.
Wherein the second coefficient is represented as
Has a dimension of 2L K,2L representing the matrix W 1 K denotes the matrix W 3 K second basis vectors contained in (a).
The second base vector can be partially corrected according to actual needs, and the method comprises the following three modes;
1. when the base station comb configuration needs to feed back the precoded sub-band, the second base vector can be adjusted by one of the following sub-modes:
the first sub-mode is as follows: configuring a larger oversampling factor and increasing the number of selectable DFT matrixes;
the second sub-method comprises the following steps: the comb intercepts the second base vector.
2. And when the base station configuration part does not need to feed back the precoded sub-band, truncating the second base vector part element.
3. The second configured base vector may be phase rotated with reference to the configured middle most precoded subband.
Wherein, the terminal may feed back a partial subset and indicate its selected subset by feedback. The selected subset and the feedback indication feed back the second coefficient according to one of the following modes appointed by the base station:
the first mode comprises the following steps: sorting the amplitude of the second coefficient, selecting partial coefficients from large to small until the ratio of the sum of the powers of the partial coefficients to the total power of the second coefficient is not less than delta, and feeding back the partial coefficients by the terminal, wherein the delta is a preset threshold;
the coefficients selected are indicated using a 2L · K sized bitmap.
The second mode comprises the following steps: the feedback of the second coefficient by using the first base vector as the priority may specifically use one of the following sub-modes:
mode A: selecting/from K weighting coefficients of the optimal first basis vector 0 And the quantization precision is increased. Selecting l from K weighting coefficients of the other first base vectors 1 (l 1 ＜l 0 ) And (4) the quantization precision is properly reduced by each coefficient. The terminal indicates its selected coefficients using a bitmap of 2L · K size.
Mode B: selecting l from K weighting coefficients of the optimal first basis vector 0 And the quantization precision is increased. In all the weighting coefficients of the remaining first basis vectors, a total of M-l is selected 0 The coefficient is fed back, the value of M can be configured by the base station or is
Wherein delta M In order to preset the threshold, the quantization accuracy is appropriately reduced. The terminal may feed back its selected subset using one of the following sub-approaches.
Sub-mode B-1: the terminal indicates its selected coefficients using a bitmap of 2L · K size.
Sub-mode B-2: terminal use
Indicating the selected optimal first basis vector for reuse
The remaining M-l indicating its selection 0 A coefficient.
Mode C: terminal pair 2LThe first base vectors are sorted, and l is respectively selected from the weighting coefficients of the strong first base vectors to the weak first base vectors 0 ,l 0 -1，...,l 0 -M +1 coefficients for feedback. The terminal indicates its selected coefficients using a bitmap of 2L · K size.
The third method comprises the following steps: the second coefficient is fed back by taking the second base vector as the priority, and specifically, one of the following sub-modes can be used:
mode D: selecting L from 2L weighting coefficients of the optimal second base vector 0 And the quantization precision is increased. In all the weighting coefficients of the remaining second basis vectors, a total of M-l is selected 0 The coefficient is fed back, the value of M is configured by the base station or is
Wherein delta M In order to preset the threshold, the quantization accuracy is appropriately reduced. The terminal may feed back its selected subset using one of the following sub-approaches.
Sub-mode D-1: the terminal indicates its selected coefficients using a bitmap of 2L · K size.
Sub-mode D-2: terminal use
Indicating the selected optimal second basis vectors for reuse
The remaining M-l indicating its selection 0 A coefficient.
Mode E: the terminal sequences the K second base vectors, and selects l from the weighting coefficients of the strong second base vectors to the weak second base vectors 0 ,l 0 -1，...,l 0 -M +1 coefficients. The terminal indicates its selected coefficients using a bitmap of 2L · K size.
The fourth mode comprises the following steps: dividing the first base vectors into two groups, and feeding back the second coefficients according to the priority, wherein one of the following sub-modes can be specifically used:
mode F: in all weighting coefficients of the first basis vector in two groups, each feedback
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold; terminal passing bit map or
Indicating the selected coefficients.
Mode G: within the two packets, feedback is performed according to the priority of the first base vector, and one of the following sub-modes may be used:
sub-mode G-1: an optimal first basis vector is selected for each of the two groups. Selecting l from the weighting coefficients of the two optimal first basis vectors 0 And the quantization precision is increased. In each case a reselection among all weighting coefficients of the remaining first basis vectors in the two groups
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M In order to preset the threshold, the quantization accuracy is appropriately reduced. The terminal indicates its selected coefficients using a bitmap of 2L · K size;
sub-mode G-2: an optimal first basis vector is selected in each of the two groups. Selecting l from the weighting coefficients of the two optimal first basis vectors 0 And the quantization precision is increased. In each case a further selection of l from the weighting factors of the remaining first basis vectors in the two groups 1 (l 1 ＜l 0 ) And (4) coefficients, appropriately reducing quantization precision. Terminal using 2 L.K sizeIndicates the coefficients it selects.
Mode H: within both packets, feedback is performed according to the priority of the second base vector, and specifically one of the following sub-modes can be used:
sub-mode H-1: an optimal second basis vector is selected in each of the two groups. Selecting l from weighting coefficients of optimal second base vectors in 1 st group 0 Coefficient, selecting/from weighting coefficients of optimal second base vector in 2 nd group 0 Coefficient, increasing quantization precision. Reselecting among all the weighting coefficients of the remaining second basis vectors in both groups
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M In order to preset the threshold, the quantization accuracy is appropriately reduced. The terminal indicates its selected coefficients using a bitmap of 2L · K size;
sub-mode H-2: an optimal second basis vector is selected for each of the two groups. Selecting/from weighting coefficients of optimal second base vectors in 1 st group 0 Coefficient, selecting/from weighting coefficients of optimal second base vector in 2 nd group 0 Coefficient, increasing quantization precision. In each case a further selection of l from the weighting factors of the remaining second basis vectors in the two groups 1 (l 1 ＜l 0 ) And (4) coefficients, appropriately reducing quantization precision. The terminal indicates its selected coefficients using a bitmap of 2L · K size.
The fifth mode comprises the following steps: grouping the second coefficient, and feeding back according to the priority of the grouping, specifically, one of the following sub-modes may be used:
mode I: dividing the second coefficient into group number combinations, and selecting the most suitable combination for feedback by the terminal
Indicating a selected combination thereof;
mode J: and dividing the second coefficient into group number combinations, and selecting 1 most suitable combination by the terminal to increase the quantization precision. In the remaining combinations, l-1 combinations are selected, and the quantization precision is appropriately reduced. Log of terminal usage 2 The GroupNumber bits indicate the most appropriate combination to choose, using
The remaining combinations are indicated.
The base station may further limit the selection of the first and second basis vectors, thereby avoiding interference. The following may be specifically adopted:
the method I comprises the following steps: and the base station groups all the selectable first base vectors, informs the terminal of the first base vectors needing to be limited through signaling, and limits the feedback power. Specifically, one of the following sub-modes may be employed:
1. the base station configures power limitation on certain first base vectors, wherein after the amplitude of the weighting coefficients of the first base vectors for power limitation is quantized, the first amplitude feedback penalty factor configured by the base station cannot be exceeded;
2. the base station configuration performs power limitation on certain first base vectors, and the amplitude of the weighting coefficient of the power-limited first base vector is multiplied by a first amplitude feedback penalty factor configured by the base station and then quantized.
The second method comprises the following steps: and the base station groups all the optional second base vectors, informs the terminal of the second base vectors needing to be limited through signaling, and limits the feedback power. Specifically, one of the following sub-modes may be employed:
1. the base station configures power limitation on some second base vectors, wherein after the amplitude of the weighting coefficient of the second base vector for power limitation is quantized, a second amplitude feedback penalty factor configured by the base station cannot be exceeded;
2. and the base station configuration performs power limitation on some second base vectors, and the amplitude of the weighting coefficient of the second base vector for performing power limitation is multiplied by a second amplitude feedback penalty factor configured by the base station and then quantized.
When the resource for feeding back the CSI in the uplink is insufficient, the terminal may discard part of the feedback content according to the priority. Specifically, one of the following ways may be adopted:
the method I comprises the following steps: dynamically reducing the number of the fed-back second base vectors when the feedback resources are insufficient and the selected second base vector number K is configured by the terminal;
in a second mode, when the selected second base vector number K is configured by the base station, if the feedback resource is sufficient, uploading all parameters configured by the base station, otherwise, selecting one of the following sub-modes:
1. when precoding matrix information is fed back according to the mode one, if feedback resources are insufficient, dynamically notifying the selected coefficients through a bit map based on a certain criterion until the maximum feedback resources are reached;
2. when precoding matrix information is fed back according to the mode A or the mode C included in the mode II, if the feedback resource is insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal first base vector, and then the terminal can dynamically inform the selected coefficient through a bitmap based on a certain criterion until the maximum feedback resource is reached; when the mode B included in the mode two feeds back precoding matrix information and uses the sub-mode B-1 to feed back subset indication, if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal first base vector, and then the terminal can dynamically inform the selected coefficient through a bit map based on a certain criterion until the maximum feedback resources are reached; when precoding matrix information is fed back according to the mode B included in the mode II and subset indication is fed back by using the sub-mode B-2, if feedback resources are insufficient, the terminal only feeds back the weighting coefficient of the optimal first base vector;
3. when precoding matrix information is fed back according to the mode D included in the mode III and subset indication is fed back by using the sub-mode D-1, if feedback resources are insufficient, the terminal preferentially feeds back a weighting coefficient of an optimal second base vector, and then the terminal can dynamically inform a selected coefficient through a bit map until the maximum feedback resources are reached based on a certain criterion; when precoding matrix information is fed back according to the mode D included in the mode III and subset indication is fed back by using the sub-mode D-2, if feedback resources are insufficient, the terminal only feeds back the weighting coefficient of the optimal second base vector; when precoding matrix information is fed back according to the mode E included in the mode III, if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal second base vector, and then the terminal can dynamically inform the selected coefficient through a bit map based on a certain criterion until the maximum feedback resources are reached;
4. when precoding matrix information is fed back according to the mode F included in the mode four, if the feedback resources are insufficient, dynamically informing the selected coefficients through a bit map until the maximum feedback resources are reached; when precoding matrix information is fed back according to the sub-mode G-1 or the sub-mode G-2 included in the mode G included in the mode IV, if feedback resources are insufficient, a weighting coefficient of an optimal first base vector in a first group is fed back preferentially, a weighting coefficient of an optimal first base vector in a second group is fed back secondarily, and then a selected coefficient is informed dynamically through a bitmap on the basis of a certain criterion until the maximum feedback resources are reached; when precoding matrix information is fed back according to the sub-mode H-1 or the sub-mode H-2 included in the mode H included in the mode IV, if the feedback resources are insufficient, the weighting coefficient of the optimal second base vector in the first group is fed back preferentially, then the weighting coefficient of the optimal second base vector in the second group is fed back, and then the selected coefficient is informed dynamically through a bitmap until the maximum feedback resources are reached;
5. when precoding matrix information is fed back according to the mode I included in the mode five and a selected packet is fed back by using a bit map, if the feedback resource is insufficient, the base station is dynamically informed of the selected packet according to the bit map based on a certain criterion until the maximum feedback resource is reached; and when precoding matrix information is fed back according to the mode J included by the mode five, if the feedback resource is insufficient, preferentially feeding back a weighting coefficient corresponding to the optimal grouping.
According to the technical scheme provided by the first embodiment and the second embodiment of the invention, the precoding matrix information fed back by the terminal comprises first base vector information, second base vector information, and amplitude and phase information of a second coefficient; the weighting coefficient of the first base vector in one pre-coding sub-band is the first coefficient, and by utilizing the correlation of the pre-coding vectors of different pre-coding sub-bands, a matrix formed by the first coefficients of all the pre-coding sub-bands can be compressed by using the second base vector on the frequency domain, and the weighting coefficient of the second base vector is the second coefficient. Therefore, the CSI feedback cost can be reduced, and the higher CSI feedback performance is ensured.
The configuration operation of the base station does not have a fixed front-back order, and the configuration information can be combined and sent to the terminal.
Third embodiment
Fig. 5 is a schematic structural diagram of a terminal according to a third embodiment of the present invention, and as shown in fig. 5, the terminal includes:
the feedback unit is used for feeding back precoding matrix information, wherein the precoding matrix information comprises first base vector information, second base vector information, and amplitude and phase information of a second coefficient;
feeding back a precoding vector in a precoding subband, wherein the precoding vector is linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
Wherein the second basis vectors represent K DFT basis vectors selected from a DFT matrix or an oversampled DFT matrix having an oversampling factor O f The value of (a) is one of the following: 1. 2, 4 and 8.
Before the feedback unit feeds back the precoding matrix information, the terminal further includes:
the processing unit is used for obtaining precoding matrix information according to the result of channel estimation and the configuration information sent by the base station; the configuration information sent by the base station comprises at least one of the following: the base station is configured with information such as a frequency domain range needing to feed back CSI, a feedback mode and feedback subset indication of a configured second coefficient, a configured first amplitude feedback penalty factor, a first base vector indicating that power limitation needs to be performed, a configured second amplitude feedback penalty factor, a second base vector indicating that power limitation needs to be performed and the like. The specific process is as follows:
wherein, this terminal station still includes:
a receiving unit, configured to receive, before a terminal feeds back precoding matrix information, a frequency domain range of CSI needing to be fed back, where the frequency domain range of CSI includes: the method comprises the steps that a pre-coding sub-band needing to feed back CSI or a pre-coding sub-band needing to comb-feed back CSI and the sparsity degree or a pre-coding sub-band needing not to feed back CSI;
a processing unit, configured to modify the second base vector by one of the following manners when the base station comb configures a subband requiring feedback precoding:
the first method is as follows: the base station configures a larger oversampling factor and increases the number of selectable DFT matrixes;
the second method comprises the following steps: the terminal comb-intercepts DFT base vectors according to the pre-coding sub-bands of the pre-coding information needing to be fed back;
or, when the base station configures a part of the sub-bands which do not need to feed back precoding information, cutting off corresponding position elements of the precoding sub-bands which do not need to feed back precoding information in the DFT base vector;
or the base station configures whether to perform phase rotation on the second base vector or not, and takes the configured middle pre-coding sub-band as reference.
The CSI feedback band refers to a frequency domain range in which the base station needs to feed back CSI.
The precoding sub-band is a frequency domain unit, and the number of the RBs contained in the precoding sub-band is determined by the number of the RBs configured by the base station or contained in the CSI feedback frequency band and the number of the second base vectors used, namely the number of the RBs is
RBNum is the number of RBs contained in the CSI feedback band, K is the CSI inverseA second number of basis vectors used for the feed band.
Wherein the second coefficient is represented as
Has a dimension of 2L × K,2L represents the matrix W 1 K denotes the matrix W 3 K second basis vectors contained in (a).
The receiving unit is further configured to receive a feedback mode and a feedback subset indication of a second coefficient sent by the base station before the terminal feeds back the precoding matrix information;
the processing unit is further configured to select the fed back second coefficient by one of:
the first method is as follows: feeding back a second coefficient according to the amplitude of the second coefficient as the priority;
the second method comprises the following steps: feeding back a second coefficient by taking the first base vector as priority
The third method comprises the following steps: feeding back a second coefficient by taking the second base vector as priority;
the method is as follows: dividing the first base vectors into two groups, and dividing the 1 st to Lth first base vectors, namely W 1 As a first group, the L +1 to 2L first base vectors, i.e., W 1 As a second group, feeding back a second coefficient according to the priority inside the packet;
the fifth mode is as follows: and grouping the second coefficients, and feeding back the second coefficients according to the priority of the grouping.
Wherein, the first mode includes:
sorting the amplitude of the second coefficient, selecting partial coefficients from large to small until the ratio of the sum of the powers of the partial coefficients to the total power of the second coefficient is not less than delta, and feeding back the partial coefficients by the terminal, wherein the delta is a preset threshold;
the coefficients selected are indicated using a 2L · K sized bitmap.
Wherein, the second mode includes:
mode A: selecting l from K weighting coefficients of the optimal first basis vector 0 A coefficient, which is selected from the K weighting coefficients of the first base vectors 1 Coefficient of l 1 ＜l 0 The selected coefficients are indicated using a bitmap of 2L · K size;
alternatively, the mode B: selecting l from K weighting coefficients of the optimal first basis vector 0 A coefficient, and selecting M-l in total from all the weighting coefficients of the rest first base vectors 0 The coefficient is fed back, the value of M is configured by the base station or is
Wherein delta M Is a preset threshold value; feeding back its selected subset using one of the following sub-ways: sub-mode B-1: the coefficients selected are indicated using a bitmap of 2L · K size; subformulae B-2: use of
Indicating the selected optimal first basis vector for reuse
The remaining M-l indicating its selection 0 A coefficient;
alternatively, the mode C: 2L first base vectors are sequenced, and L are respectively selected from the weighting coefficients of the strong first base vectors to the weak first base vectors 0 ,l 0 -1，...,l 0 -M +1 coefficients are fed back, the selected coefficients being indicated using a bitmap of size 2L · K.
Wherein, the third mode includes:
mode D, select L among 2L weighting coefficients of the optimal second basis vector 0 A coefficient, and selecting M-l in total from all the weighting coefficients of the rest second base vectors 0 The value of M being configured by the base station or being
Wherein delta M Is a preset threshold value; feeding back its selected subset using one of the following sub-ways: sub-mode D-1: the coefficients selected are indicated using a bitmap of 2L · K size; sub-mode D-2: use of
Indicating the selected optimal second basis vectors for reuse
The remaining M-l indicating its selection 0 A coefficient;
alternatively, the mode E: sequencing the K second base vectors, and respectively selecting l from the weighting coefficients of the strong second base vectors to the weak second base vectors 0 ,l 0 -1，...,l 0 -M +1 coefficients, whose selected coefficients are indicated using a bitmap of size 2L · K.
Wherein, mode four includes:
mode F: mode F: of all the weighting coefficients of the first basis vector in the two groups, each feedback
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold value; by means of a bit map or
Indicating the selected coefficients;
alternatively, the mode G: within the two packets, the coefficients fed back according to the priority of the first base vector and whose selection is indicated using a bitmap of 2L · K size include: sub-mode G-1: selecting an optimal first base vector in each of the two groups, and selecting l from the weighting coefficients of the two optimal first base vectors 0 Coefficient of the remaining first basis in two groupsReselection of each of all weighting coefficients of the vector
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold value; or sub-mode G-2: selecting an optimal first base vector in each of the two groups, and selecting l from the weighting coefficients of the two optimal first base vectors 0 Coefficients, each of which is selected again from the weighting coefficients of the remaining first basis vectors in the two groups 1 Coefficient of l 1 ＜l 0 ，；
Alternatively, the mode H: within the two packets, the coefficients fed back according to the priority of the second base vector and whose selection is indicated using a bitmap of 2L · K size include: sub-mode H-1: selecting an optimal second base vector in each of two groups, and selecting l from weighting coefficients of the optimal second base vector in the 1 st group 0 Coefficient, selecting/from weighting coefficients of optimal second base vector in 2 nd group 0 Coefficients, each of which is selected among all the weighting coefficients of the remaining second basis vectors in the two groups
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold; or sublay H-2: selecting an optimal second base vector in each of the two groups, and selecting l from the weighting coefficients of the optimal second base vectors in the 1 st group 0 Coefficient, selected from the weighting coefficients of the optimal second basis vectors in the 2 nd groupl 0 Coefficients, each of the weighting coefficients of the remaining second basis vectors in the two groups being selected again by l 1 Coefficient of (a) l 1 ＜l 0 。
Wherein, mode five includes:
mode I: dividing the second coefficient into group number combinations, and selecting the most suitable combination for feedback by the terminal
Indicating a selected combination thereof;
alternatively, the method J: dividing the second coefficients into group number combinations, selecting 1 most suitable combination, selecting l-1 combinations from the remaining combinations, using log 2 GroupNumberbits indicate the most appropriate combination of choices, use
The remaining combinations are indicated.
The receiving unit is further configured to receive a first signaling sent by the base station before the terminal feeds back the precoding matrix information; the first signaling comprises a first amplitude feedback penalty factor configured by the base station and a first base vector indicating that power limitation needs to be performed, and is used for performing power limitation on a weighting coefficient of the first base vector needing to be performed with power limitation;
the processing unit is further configured to limit that the amplitude of the weighted coefficient of the fed-back first base vector needing to be power-limited cannot exceed a first amplitude feedback penalty factor configured by the base station after quantization, or perform quantization after multiplying the amplitude of the weighted coefficient of the first base vector needing to be power-limited by the first amplitude feedback penalty factor configured by the base station;
and/or, the receiving unit is further configured to receive a second signaling sent by the base station before the terminal feeds back the precoding matrix information; the second signaling comprises a second amplitude feedback penalty factor configured by the base station and a second base vector indicating that power limitation needs to be performed, and is used for performing power limitation on a weighting coefficient of the second base vector needing to be performed with the power limitation;
the processing unit is further configured to restrict that the magnitude of the weighting coefficient of the fed-back second base vector that needs to be power-limited cannot exceed a second magnitude feedback penalty factor configured by the base station after quantization, or perform quantization after multiplying the magnitude of the weighting coefficient of the second base vector that needs to be power-limited by the second magnitude feedback penalty factor configured by the base station.
Wherein the processing unit is also used for
Dynamically reducing the number of the fed-back second base vectors when the feedback resources are insufficient and the selected second base vector number K is configured by the terminal;
or when the selected second base vector number K is configured by the base station, if the feedback resources are sufficient, uploading all parameters configured by the base station, otherwise, selecting one of the following modes:
when precoding matrix information is fed back according to the mode one, if feedback resources are insufficient, dynamically notifying the selected coefficients through a bit map based on a certain criterion until the maximum feedback resources are reached;
or when precoding matrix information is fed back according to the mode A or the mode C included in the mode II, if the feedback resource is insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal first base vector, and then the terminal dynamically informs the selected coefficient through a bit map based on a certain criterion until the maximum feedback resource is reached; when the mode B included in the mode II feeds back precoding matrix information and uses the sub-mode B-1 to feed back subset indication, if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal first base vector, and then the terminal dynamically informs the selected coefficient through a bit map based on a certain criterion until the maximum feedback resources are reached; when precoding matrix information is fed back according to the mode B included in the mode II and subset indication is fed back by using the sub-mode B-2, if feedback resources are insufficient, the terminal only feeds back the weighting coefficient of the optimal first base vector;
or when precoding matrix information is fed back according to the mode D included in the mode III and a subset is fed back for indication by using the sub-mode D-1, if the feedback resource is insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal second base vector, and then the terminal dynamically informs the selected coefficient through a bitmap based on a certain criterion until the maximum feedback resource is reached; when precoding matrix information is fed back according to the mode D included in the mode III and subset indication is fed back by using the sub-mode D-2, if feedback resources are insufficient, the terminal only feeds back the weighting coefficient of the optimal second base vector; when precoding matrix information is fed back according to the mode E included in the mode III, if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal second base vector, and then the terminal dynamically informs the selected coefficient through a bit map based on a certain criterion until the maximum feedback resources are reached;
or when feeding back precoding matrix information according to the mode F included in the mode four, if the feedback resource is insufficient, dynamically notifying the selected coefficient through a bitmap until the maximum feedback resource is reached; when precoding matrix information is fed back according to the sub-mode G-1 or the sub-mode G-2 included in the mode G included in the mode IV, if feedback resources are insufficient, a weighting coefficient of an optimal first base vector in a first group is fed back preferentially, a weighting coefficient of an optimal first base vector in a second group is fed back secondarily, and then a selected coefficient is informed dynamically through a bitmap on the basis of a certain criterion until the maximum feedback resources are reached; when precoding matrix information is fed back according to the sub-mode H-1 or the sub-mode H-2 included in the mode H included in the mode IV, if the feedback resources are insufficient, the weighting coefficient of the optimal second base vector in the first group is fed back preferentially, then the weighting coefficient of the optimal second base vector in the second group is fed back, and then the selected coefficient is informed dynamically through a bitmap until the maximum feedback resources are reached;
or, when feeding back precoding matrix information according to the mode I included in the mode five and feeding back a selected packet by using a bit map, if the feedback resource is insufficient, dynamically notifying the base station of the selected packet according to the bit map based on a certain criterion until the maximum feedback resource is reached; and when precoding matrix information is fed back according to the mode J included in the mode five, if the feedback resource is insufficient, preferentially feeding back a weighting coefficient corresponding to the optimal grouping.
Example IV
Fig. 6 is a schematic structural diagram of a base station according to a fourth embodiment of the present invention, and as shown in fig. 6, the base station includes:
the terminal comprises a receiving unit and a processing unit, wherein the receiving unit is used for receiving precoding matrix information fed back by the terminal, and the precoding matrix information comprises first base vector information, second base vector information and amplitude and phase information of a second coefficient;
feeding back a precoding vector in a precoding subband, wherein the precoding vector is linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
Wherein, this base station still includes:
the configuration unit is used for configuring a frequency domain range needing to feed back CSI before the base station receives the precoding matrix information fed back by the terminal;
and the sending unit is used for sending the configured frequency domain range needing to feed back the CSI to the terminal so that the terminal can determine the precoding sub-band needing to feed back the precoding information according to the frequency domain range of the CSI.
Wherein the frequency domain range of the configured CSI comprises: the method comprises the steps that a precoding sub-band needing to feed back CSI, or a precoding sub-band needing to comb-feed back CSI and the sparsity degree, or a precoding sub-band needing not to feed back CSI.
Wherein the content of the first and second substances,
the configuration unit is further configured to configure a feedback mode and a feedback subset indication of the second coefficient before the base station receives the precoding matrix information fed back by the terminal;
the sending unit is further configured to send the configured feedback mode and feedback subset indication of the second coefficient to the terminal, so that the terminal indicates to feed back the second coefficient according to the feedback mode and feedback subset indication of the second coefficient;
the feedback mode of the second coefficient comprises one of the following modes:
the first method is as follows: feeding back a second coefficient according to the amplitude of the second coefficient;
the second method comprises the following steps: feeding back a second coefficient by taking the first base vector as priority
The third method comprises the following steps: feeding back a second coefficient by taking the second base vector as priority;
the method is as follows: dividing the first base vectors into two groups, and dividing the 1 st to the L th first base vectors, namely W 1 As a first group, the L +1 to 2L first base vectors, i.e., W 1 As a second group, feeding back a second coefficient according to the priority inside the packet;
the fifth mode is as follows: grouping the second coefficients, and feeding back the second coefficients according to the priority of the grouping;
the feedback subset indicates a manner for instructing the terminal to feed back the subset of the second coefficients.
Wherein the second coefficient is expressed as
Has a dimension of 2L K,2L representing the matrix W 1 K denotes the matrix W 3 K second basis vectors contained in (a).
Wherein, the mode one includes:
sorting the amplitude of the second coefficient, selecting partial coefficient power from large to small until the ratio of the sum of the partial coefficient power to the total power of the second coefficient is not less than delta, and feeding back the partial coefficient by the terminal, wherein the delta is a preset threshold;
the coefficients selected are indicated using a 2L · K sized bitmap.
Wherein, the second mode includes:
mode A: selecting K coefficients corresponding to the optimal first base vectorl 0 One coefficient, and selecting one coefficient from K coefficients corresponding to the rest first base vectors 1 Coefficient of (a) l 1 ＜l 0 The coefficients it selects are indicated using a bitmap of 2L · K size;
alternatively, the mode B: selecting/from K coefficients corresponding to the optimal first base vector 0 A coefficient, and selecting M-l in total from all coefficients corresponding to the rest first base vectors 0 The coefficient is fed back, the value of M is configured by the base station or is
Wherein delta M Is a preset threshold; feeding back its selected subset using one of the following sub-ways: sub-mode B-1: the coefficients selected are indicated using a bitmap of 2L · K size; sub-mode B-2: use of
Indicating the selected optimal first basis vector, reuse
The remaining M-l indicating its selection 0 A coefficient;
alternatively, the mode C: sequencing 2L first base vectors, and respectively selecting L from coefficients corresponding to strong to weak first base vectors 0 ,l 0 -1，...,l 0 -M +1 coefficients are fed back, the selected coefficients being indicated using a bitmap of size 2L · K.
Wherein, mode three includes:
mode D, select L from the 2L coefficients corresponding to the optimal second basis vector 0 A coefficient, and a total of M-l is selected from all the coefficients corresponding to the rest of the second base vectors 0 A value of M is configured by the base station or is
Wherein delta M Is a preset threshold value; feeding back its selected subset using one of the following sub-ways: sub-mode D-1: using 2 L.K sized bit map to indicate its selected familyCounting; sub-mode D-2: use of
Indicating the selected optimal second basis vectors for reuse
The remaining M-l indicating its selection 0 A coefficient;
alternatively, the mode E: sequencing the K second base vectors, and respectively selecting l from coefficients corresponding to the strong second base vectors to the weak second base vectors 0 ,l 0 -1，...,l 0 -M +1 coefficients, whose selected coefficients are indicated using a bitmap of size 2L · K.
Wherein, mode four includes:
mode F: within two groups, each feeding back
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold value; by means of a bit map or
Indicating the selected coefficients;
alternatively, the mode G: within the two packets, the coefficients fed back according to the priority of the first base vector and whose selection is indicated using a bitmap of 2L · K size include: sub-mode G-1: selecting an optimal first base vector in each of the two groups, and selecting l from corresponding coefficients of the two optimal first base vectors 0 Coefficients, the remaining first basis vectors in the two groups corresponding to each of all coefficients
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold; or sub-mode G-2: selecting an optimal first base vector in each of the two groups, and selecting l from corresponding coefficients of the two optimal first base vectors 0 A coefficient, each of the other coefficients corresponding to the first basis vectors in the two groups is selected 1 Coefficient of l 1 ＜l 0 ，；
Alternatively, the mode H: within the two packets, the coefficients fed back according to the priority of the second base vector and whose selection is indicated using a bitmap of 2L · K size include: sublevel H-1: selecting an optimal second base vector in each of the two groups, and selecting l from the coefficients corresponding to the optimal second base vectors in the 1 st group 0 Coefficient, i is selected from the corresponding coefficients of the optimal second basis vector in the 2 nd group 0 Coefficients, the remaining second basis vectors in the two groups corresponding to each of all coefficients
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold; or sublay H-2: selecting an optimal second base vector in each of the two groups, and selecting l from the corresponding coefficients of the optimal second base vector in the 1 st group 0 Coefficient, i is selected from the corresponding coefficients of the optimal second basis vector in the 2 nd group 0 A coefficient, each of the other coefficients corresponding to the second basis vectors in the two groups is selected to be l 1 Coefficient of (a) l 1 ＜l 0 。
Wherein, mode five includes:
mode I: dividing the second coefficient into group number combinations, and the terminal selects the most suitable combination for feedback
Indicating a selected combination thereof;
alternatively, the method J: dividing the second coefficients into group number combinations, selecting 1 most suitable combination, selecting l-1 combinations from the remaining combinations, using log 2 The GroupNumber bits indicate the most appropriate combination to choose, using
The remaining combinations are indicated.
Wherein the content of the first and second substances,
the configuration unit is further configured to configure a first amplitude feedback penalty factor and a first base vector indicating that power limitation needs to be performed;
the sending unit is further configured to send a first signaling to the terminal before the base station receives the precoding matrix information fed back by the terminal;
the first signaling comprises a first amplitude feedback penalty factor configured by the base station and a first base vector indicating that power limitation needs to be performed, and is used for limiting the power of a coefficient corresponding to the first base vector needing to be performed with the power limitation;
and/or the configuration unit is further configured to configure a second amplitude feedback penalty factor and a second base vector indicating that power limitation needs to be performed;
the sending unit is further configured to send a second signaling to the terminal before the base station receives the precoding matrix information fed back by the terminal;
the second signaling comprises a second amplitude feedback penalty factor configured by the base station and a second base vector indicating that power limitation needs to be performed, and is used for limiting the power of a coefficient corresponding to the second base vector needing to be performed with power limitation.
Wherein the first amplitude feedback penalty factor is
Or
Or the second amplitude feedback penalty factor is
Or
The embodiment of the present invention further provides a terminal, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the computer program is executed by the processor, the method for channel state information CSI feedback executed by any of the above terminals is implemented.
The embodiment of the present invention further provides a base station, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the computer program is executed by the processor, the base station implements the method for channel state information CSI feedback executed by any one of the base stations.
An embodiment of the present invention further provides a computer-readable storage medium, where an information processing program is stored, and when the information processing program is executed by a processor, the information processing program implements any one of the methods for CSI feedback.
It will be understood by those of ordinary skill in the art that all or some of the steps of the methods, systems, functional modules/units in the devices disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. In a hardware implementation, the division between functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be performed by several physical components in cooperation. Some or all of the components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as is well known to those skilled in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can accessed by a computer. In addition, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media as known to those skilled in the art.
Although the embodiments of the present invention have been described above, the above description is only for the purpose of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (25)
1. A Channel State Information (CSI) feedback method comprises the following steps:
receiving a feedback mode and a feedback subset indication of a second coefficient sent by a base station; wherein the feedback subset indicates a manner for instructing the terminal to feed back the subset of the second coefficients;
the terminal feeds back precoding matrix information, wherein the precoding matrix information comprises first base vector information, second base vector information, and amplitude and phase information of a second coefficient;
feeding back a precoding vector in a precoding subband, wherein the precoding vector is linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
2. The method of claim 1, wherein the second basis vectors represent K DFT basis vectors selected from a DFT matrix or an oversampled DFT matrix, the oversampled DFT matrix having an oversampling factor O f Is one of the following: 1. 2, 4 and 8.
3. The method according to claim 2, wherein before the terminal feeds back the precoding matrix information, the method further comprises:
receiving a frequency domain range of CSI to be fed back, which is sent by a base station, wherein the frequency domain range of the CSI comprises: a precoding sub-band requiring CSI feedback, or a precoding sub-band requiring CSI comb feedback and sparsity, or a precoding sub-band not requiring CSI feedback;
when the base station comb configures the precoding sub-band which needs to feed back the precoding information, the second base vector is corrected by one of the following modes:
the first method is as follows: when a base station configures a larger oversampling factor, the number of selectable DFT matrixes is increased;
the second method comprises the following steps: the terminal comb-intercepts DFT base vectors according to the pre-coding sub-bands of the pre-coding information needing to be fed back;
or, when the base station configures a part of the sub-bands which do not need to feed back precoding information, cutting off corresponding position elements of the precoding sub-bands which do not need to feed back precoding information in the DFT base vector;
or the base station configures whether to perform phase rotation on the second base vector, and takes the configured middle pre-coding sub-band as reference.
4. The method of claim 1, wherein the CSI feedback band refers to a frequency domain range where a base station configuration requires CSI feedback.
5. The method of claim 1, wherein the precoding subband is a frequency domain unit and comprises a number of RBs determined by a configuration of the base station or by a number of RBs comprised in the CSI feedback band and a second number of basis vectors used, that is, the number of RBs is
RBNum is the number of RBs contained in the CSI feedback band, and K is the number of second base vectors used by the CSI feedback band.
6. The method of claim 1, wherein the second coefficient is represented as
Has a dimension of 2L × K,2L represents the matrix W 1 K denotes a matrix W 3 K second basis vectors contained in (a).
7. The method of claim 1,
feeding back a second coefficient in the precoding matrix information by one of the following modes:
the method I comprises the following steps: feeding back a second coefficient according to the priority level of the amplitude of the second coefficient;
the second method comprises the following steps: feeding back a second coefficient by taking the first base vector as priority;
the third method comprises the following steps: feeding back a second coefficient by taking the second base vector as priority;
the method four comprises the following steps:dividing the first base vectors into two groups, and dividing the 1 st to Lth first base vectors, namely W 1 As a first group, the L +1 to 2L first base vectors, i.e., W 1 As a second group, feeding back a second coefficient according to the priority inside the packet;
the fifth mode is as follows: and grouping the second coefficients, and feeding back the second coefficients according to the priority of the grouping.
8. The method of claim 7, wherein the first mode comprises:
sorting by the amplitude of the second coefficient, selecting partial coefficients from large to small until the ratio of the sum of the powers of the partial coefficients to the total power of the second coefficient is not less than delta, and feeding back the partial coefficients by the terminal, wherein delta is a preset threshold;
the coefficients selected are indicated using a 2L · K sized bitmap.
9. The method of claim 7, wherein the second mode comprises:
mode A: selecting l from K weighting coefficients of the optimal first basis vector 0 A coefficient, which is selected from the K weighting coefficients of the first base vectors 1 Coefficient of l 1 ＜l 0 The selected coefficients are indicated using a bitmap of 2L · K size;
alternatively, the mode B: selecting/from K weighting coefficients of the optimal first basis vector 0 A coefficient, and selecting M-l in total from all the weighting coefficients of the rest first base vectors 0 The coefficient is fed back, the value of M is configured by the base station or is
Wherein delta M Is a preset threshold value; feeding back its selected subset using one of the following sub-ways: subformulae B-1: the coefficients selected are indicated using a bitmap of 2L · K size; sub-mode B-2: use of
bits indicate the selected optimal first basis vector, which is then used
The remaining M-l indicating its selection 0 A coefficient;
alternatively, the mode C: 2L first base vectors are sequenced, and L are respectively selected from the weighting coefficients of the strong first base vectors to the weak first base vectors 0 ,l 0 -1，...,l 0 -M +1 coefficients are fed back, the selected coefficients being indicated using a bitmap of size 2L · K.
10. The method of claim 7, wherein the third method comprises:
mode D, select L among 2L weighting coefficients of the optimal second basis vector 0 A coefficient, and selecting M-l in total from all the weighting coefficients of the rest second base vectors 0 The value of M being configured by the base station or being
Wherein delta M Is a preset threshold value; feeding back its selected subset using one of the following sub-ways: sub-mode D-1: the coefficients it selects are indicated using a bitmap of 2L · K size; sub-mode D-2: use of
Indicating the selected optimal second basis vectors for reuse
The remaining M-l indicating its selection 0 A coefficient;
alternatively, the mode E: sequencing the K second base vectors, and respectively selecting l from the weighting coefficients of the strong second base vectors to the weak second base vectors 0 ,l 0 -1，...,l 0 -M +1 coefficients, whose selected coefficients are indicated using a bitmap of size 2L · K.
11. The method of claim 7, wherein the fourth mode comprises:
mode F: of all the weighting coefficients of the first basis vector in the two groups, each feedback
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold value; by means of a bit map or
Indicating the selected coefficients;
alternatively, the mode G: within the two packets, the coefficients fed back according to the priority of the first base vector and whose selection is indicated using a bitmap of 2L · K size include: sub-mode G-1: selecting an optimal first base vector in each of the two groups, and selecting l from the weighting coefficients of the two optimal first base vectors 0 Coefficients, each of which is selected among all the weighting coefficients of the remaining first basis vectors in the two groups
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold value; or sub-mode G-2: selecting an optimal first base vector in each of the two groups, and selecting l from the weighting coefficients of the two optimal first base vectors 0 Coefficients, each of which is selected again from the weighting coefficients of the remaining first basis vectors in the two groups 1 Coefficient of l 1 ＜l 0 ，；
Alternatively, the mode H: within the two packets, the coefficients fed back according to the priority of the second base vector and whose selection is indicated using a bitmap of 2L · K size include: sub-mode H-1: selecting an optimal second base vector in each of two groups, and selecting l from weighting coefficients of the optimal second base vector in the 1 st group 0 Coefficient, selecting/from weighting coefficients of optimal second base vector in 2 nd group 0 Coefficients, each of which is selected among all the weighting coefficients of the remaining second basis vectors in the two groups
The number of the coefficients is such that,
is configured by the base station or is
Wherein delta M Is a preset threshold value; or sublay H-2: selecting an optimal second base vector in each of two groups, and selecting l from weighting coefficients of the optimal second base vectors in the 1 st group 0 Coefficient, selecting/from weighting coefficients of optimal second base vector in 2 nd group 0 Coefficients, each of which is selected again from the weighting coefficients of the remaining second basis vectors in the two groups 1 Coefficient of l 1 ＜l 0 。
12. The method of claim 7, wherein the fifth mode comprises:
mode I: dividing the second coefficient into group number combinations, and selecting the most suitable combination for feedback by the terminal
Indicating its selected groupCombining;
alternatively, the method J: dividing the second coefficients into group number combinations, selecting 1 most suitable combination, and selecting l-1 combinations from the rest, using log 2 The GroupNumber bits indicates the most appropriate combination of selections to use
The remaining combinations are indicated.
13. The method of claim 1, wherein before the terminal feeds back the precoding matrix information, the method further comprises:
receiving a first signaling sent by a base station; the first signaling comprises a first amplitude feedback penalty factor configured by the base station and a first base vector indicating that power limitation needs to be performed, and is used for performing power limitation on a weighting coefficient of the first base vector needing to be performed with power limitation;
after the amplitude of the weighting coefficient of the first base vector needing power limitation fed back by the terminal is quantized, the weighting coefficient cannot exceed a first amplitude feedback penalty factor configured by the base station, or after the amplitude of the weighting coefficient of the first base vector needing power limitation is multiplied by the first amplitude feedback penalty factor configured by the base station, the quantization is carried out;
and/or receiving a second signaling sent by the base station; the second signaling comprises a second amplitude feedback penalty factor configured by the base station and a second base vector indicating that power limitation needs to be performed, and is used for performing power limitation on a weighting coefficient of the second base vector needing power limitation;
and after the amplitude of the weighting coefficient of the second base vector needing power limitation fed back by the terminal is quantized, the weighting coefficient cannot exceed a second amplitude feedback penalty factor configured by the base station, or after the amplitude of the weighting coefficient of the second base vector needing power limitation is multiplied by the second amplitude feedback penalty factor configured by the base station, the quantization is carried out.
14. The method according to any of claims 7-12, wherein the feeding back precoding matrix information comprises:
dynamically reducing the number of the fed-back second base vectors when the feedback resources are insufficient and the selected second base vector number K is configured by the terminal;
or when the selected second base vector number K is configured by the base station, uploading all parameters configured by the base station if the feedback resources are sufficient, otherwise, selecting one of the following modes:
when precoding matrix information is fed back according to the mode one, if feedback resources are insufficient, dynamically notifying the selected coefficients through a bit map based on a certain criterion until the maximum feedback resources are reached;
or when precoding matrix information is fed back according to the mode A or the mode C included in the mode II, if the feedback resource is insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal first base vector, and then the terminal dynamically informs the selected coefficient through a bit map based on a certain criterion until the maximum feedback resource is reached; when the mode B included in the mode II feeds back precoding matrix information and uses a sub-mode B-1 to feed back subset indication, if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal first base vector, and then the terminal dynamically informs the selected coefficient through a bitmap based on a certain criterion until the maximum feedback resources are reached; when precoding matrix information is fed back according to the mode B included in the mode II and subset indication is fed back by using the sub-mode B-2, if feedback resources are insufficient, the terminal only feeds back the weighting coefficient of the optimal first base vector;
or when precoding matrix information is fed back according to the mode D included in the mode III and subset indication is fed back by using the sub-mode D-1, if the feedback resource is insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal second base vector, and then the terminal dynamically informs the selected coefficient through a bit map until the maximum feedback resource is reached based on a certain criterion; when precoding matrix information is fed back according to the mode D included in the mode III and subset indication is fed back by using the sub-mode D-2, if feedback resources are insufficient, the terminal only feeds back the weighting coefficient of the optimal second base vector; when precoding matrix information is fed back according to the mode E included in the mode III, if the feedback resources are insufficient, the terminal preferentially feeds back the weighting coefficient of the optimal second base vector, and then the terminal dynamically informs the selected coefficient through a bit map based on a certain criterion until the maximum feedback resources are reached;
or when feeding back precoding matrix information according to the mode F included in the mode four, if the feedback resource is insufficient, dynamically notifying the selected coefficient through a bit map until the maximum feedback resource is reached; when precoding matrix information is fed back according to the sub-mode G-1 or the sub-mode G-2 included in the mode G included in the mode IV, if feedback resources are insufficient, a weighting coefficient of an optimal first base vector in a first group is fed back preferentially, a weighting coefficient of an optimal first base vector in a second group is fed back secondarily, and then a selected coefficient is informed dynamically through a bitmap on the basis of a certain criterion until the maximum feedback resources are reached; when precoding matrix information is fed back according to the sub-mode H-1 or the sub-mode H-2 included in the mode H included in the mode IV, if the feedback resources are insufficient, the weighting coefficient of the optimal second base vector in the first group is fed back preferentially, then the weighting coefficient of the optimal second base vector in the second group is fed back, and then the selected coefficient is informed dynamically through a bitmap until the maximum feedback resources are reached;
or when precoding matrix information is fed back according to the mode I included in the mode five and a selected packet is fed back by using a bit map, if the feedback resource is insufficient, the base station is dynamically informed of the selected packet according to the bit map based on a certain criterion until the maximum feedback resource is reached; and when precoding matrix information is fed back according to the mode J included by the mode five, if the feedback resource is insufficient, preferentially feeding back a weighting coefficient corresponding to the optimal grouping.
15. A Channel State Information (CSI) feedback method comprises the following steps:
the base station configures a feedback mode and a feedback subset indication of a second coefficient and sends the feedback mode and the feedback subset indication to the terminal so that the terminal can conveniently feed back the second coefficient according to the feedback mode and the feedback subset indication of the second coefficient; wherein the feedback subset indicates a manner for instructing the terminal to feed back the subset of the second coefficients;
the base station receives precoding matrix information fed back by the terminal, wherein the precoding matrix information comprises first base vector information, second base vector information and amplitude and phase information of a second coefficient;
the precoding vectors in the feedback precoding sub-band are linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
16. The method of claim 15, wherein before the base station receives the precoding matrix information fed back by the terminal, the method further comprises:
and the base station configures a frequency domain range needing to feed back the CSI and sends the frequency domain range to the terminal so that the terminal can determine a precoding sub-band needing to feed back precoding information according to the frequency domain range of the CSI.
17. The method of claim 16, wherein the configured frequency domain range of CSI comprises: the method comprises the steps that a precoding sub-band needing to feed back CSI, or a precoding sub-band needing to comb-feed back CSI and the sparsity degree, or a precoding sub-band needing not to feed back CSI.
18. The method of claim 15, wherein before the base station receives the precoding matrix information fed back by the terminal, the method further comprises:
the feedback mode of the second coefficient comprises one of the following modes:
the first method is as follows: feeding back a second coefficient according to the amplitude of the second coefficient as the priority;
the second method comprises the following steps: feeding back a second coefficient by taking the first base vector as priority;
the third method comprises the following steps: feeding back a second coefficient by taking the second base vector as priority;
the method is as follows: dividing the first base vectors into two groups, and dividing the 1 st to the L th first base vectors, namely W 1 As a first group, the L +1 to the 2L first base vectors, i.e., W 1 As a second group, feeding back a second coefficient according to the priority inside the packet;
the fifth mode is as follows: grouping the second coefficients, and feeding back the second coefficients according to the priority of the grouping;
the feedback subset indicates a manner for instructing the terminal to feed back the subset of the second coefficients.
19. The method of claim 15, wherein before the base station receives the precoding matrix information fed back by the terminal, the method further comprises:
sending a first signaling and/or a second signaling to a terminal;
the first signaling comprises a first amplitude feedback penalty factor configured by the base station and a first base vector indicating that power limitation needs to be performed, and is used for performing power limitation on a weighting coefficient of the first base vector needing to be performed with power limitation; the second signaling comprises a second amplitude feedback penalty factor configured by the base station and a second base vector indicating that power limitation needs to be performed, and is used for performing power limitation on the weighting coefficient of the second base vector needing to be performed with the power limitation.
20. The method of claim 19,
the first amplitude feedback penalty factor is
Or
Or the second amplitude feedback penalty factor is
Or alternatively
21. A terminal, comprising:
a feedback unit, configured to receive a feedback mode and a feedback subset indication of a second coefficient sent by a base station; wherein the feedback subset indicates a manner for instructing the terminal to feed back the subset of the second coefficients; feeding back precoding matrix information, wherein the precoding matrix information comprises first base vector information, second base vector information, and amplitude and phase information of a second coefficient;
feeding back a precoding vector in a precoding subband, wherein the precoding vector is linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
22. A base station, comprising:
a receiving unit, configured to configure, by a base station, a feedback mode and a feedback subset indication of a second coefficient, and send the feedback mode and the feedback subset indication to a terminal, so that the terminal can feedback the second coefficient according to the feedback mode and the feedback subset indication of the second coefficient; wherein the feedback subset indicates a manner for instructing the terminal to feed back the subset of the second coefficients; receiving precoding matrix information fed back by a terminal, wherein the precoding matrix information comprises first base vector information, second base vector information, and amplitude and phase information of a second coefficient;
the precoding vectors in the feedback precoding sub-band are linear combination of first base vectors, and a weighting coefficient used by the linear combination of the first base vectors is a first coefficient; in frequency domain units included in all CSI feedback bands, a vector formed by the first coefficients corresponding to the same first basis vector is a linear combination of second basis vectors, and the second coefficients are weighting coefficients used for the linear combination of the second basis vectors.
23. A terminal comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, the computer program, when executed by the processor, implementing the CSI feedback method according to any one of claims 1 to 14.
24. A base station comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the computer program, when executed by the processor, implementing the channel state information, CSI, feedback method according to any one of claims 15 to 20.
25. A computer-readable storage medium, having stored thereon an information processing program which, when executed by a processor, implements the channel state information, CSI, feedback method as claimed in any one of claims 1 to 20.
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| CN115037343A (en) * | 2019-03-29 | 2022-09-09 | 中兴通讯股份有限公司 | Information mapping method, information acquisition method and related equipment |
| EP4082144A4 (en) * | 2019-12-27 | 2023-09-06 | Qualcomm Incorporated | Uplink grant downlink control information for frequency domain compressed uplink precoding |
| WO2021155514A1 (en) * | 2020-02-05 | 2021-08-12 | Nokia Shanghai Bell Co., Ltd. | Channel state information (csi) feedback enhancement depicting per-path angle and delay information |
| CN113783589B (en) * | 2020-06-09 | 2023-03-10 | 华为技术有限公司 | Transmission method of channel state information and related device |
| CN117792444A (en) * | 2022-09-21 | 2024-03-29 | 维沃移动通信有限公司 | PMI (PMI) combination coefficient sending method, PMI combination coefficient sending device and terminal |
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| EP3497809B1 (en) * | 2016-08-12 | 2023-03-08 | Telefonaktiebolaget LM Ericsson (publ) | Progressive advanced csi feedback |
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| CN110535498B (en) * | 2018-12-28 | 2022-10-18 | 中兴通讯股份有限公司 | Channel State Information (CSI) feedback method and equipment |
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| CN102396162A (en) * | 2009-06-23 | 2012-03-28 | 上海贝尔股份有限公司 | Method for channel status information feedback and device thereof |
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| CN107888265A (en) * | 2016-09-30 | 2018-04-06 | 中兴通讯股份有限公司 | The feedback method and device of channel information, terminal, base station |
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