WO2012041102A1

WO2012041102A1 - Method and terminal for feeding back channel information

Info

Publication number: WO2012041102A1
Application number: PCT/CN2011/076738
Authority: WO
Inventors: 陈艺戬; 李儒岳; 李书鹏; 张峻峰
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-09-30
Filing date: 2011-06-30
Publication date: 2012-04-05
Also published as: CN101958773B; CN101958773A

Abstract

A method and terminal for feeding back channel information are disclosed in the present invention. The method includes that the terminal feeds back channel state information on a Physical Uplink Shared Channel (PUSCH) or a Physical Uplink Control Channel (PUCCH), wherein the channel state information includes: a Rank Indicator (RI), a fist codebook indicator PMI1, a second codebook indicator PMI2 and a Channel Quality Indication (CQI), and under the circumstance that the total codebook is in the form of a single codebook which is equivalent to a bi-codebook, PMI2 is used for indicating a code word in a codebook, and the codebook consists of partial code words in a group of code words set corresponding to the PMI1 in a codebook, wherein the codebook is a codebook corresponding to the RI in the total codebook; under the circumstance that the total codebook is a bi-codebook, the PMI2 is used for indicating a code word in a codebook, wherein the codebook consists of partial code words in a second codebook corresponding to the RI in the total codebook. With the present invention, the feedback overhead is reduced and the system performance is improved.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a method and a terminal for feeding back channel information. BACKGROUND In a wireless communication system, a transmitting end and a receiving end use a plurality of antennas to obtain a higher rate in a spatial multiplexing manner. Compared with the general spatial multiplexing method, an enhanced technology is that the receiving end feeds back channel information to the transmitting end, and the transmitting end uses the transmitting precoding technology to process and transmit according to the obtained channel information, thereby greatly improving the transmission performance. For single-user multi-input multi-output (MIMO), channel feature vector information can be directly used for precoding. For multi-user MIMO, more accurate channel information is needed. In the Long Term Evolution (LTE) program, the feedback of channel information is mainly based on the feedback method of a simple single codebook, and the performance of MIMO transmit precoding technology depends on the accuracy of the codebook feedback. degree. The basic principle of codebook-based channel information quantization feedback is as follows: Assuming that the limited feedback channel capacity is S bps/Hz, then the number of available codewords is N = 2 ^s . The eigenvector space of the channel matrix is quantized to form the codebook space = { , 7^ 7^}. The transmitting end and the receiving end jointly save or generate the codebook in real time (the codebook saved or generated by the transceiver end is the same). According to the channel matrix H obtained by the receiving end, the receiving end selects a code word F that best matches the channel according to a certain criterion, and feeds back the code word number back to the transmitting end. Here, the codeword sequence number is called a Precoding Matrix Indicator (PMI) „ The transmitting end finds the corresponding precoding codeword ^ according to the sequence number i, thereby obtaining channel information, indicating the feature vector of the channel. The information may be further divided into codebooks corresponding to multiple ranks, and each Rank corresponds to multiple codewords to quantize the precoding matrix formed by the channel feature vectors under the Rank. The number of non-zero feature vectors is equal. Therefore, in general, when the Rank is Ν, the codewords will have a queue. Therefore, the codebook can be divided into multiple subcodebooks according to the difference of Rank, as shown in Table 1. Table 1

The codewords to be stored in the range of Rank>l are in the form of a matrix, wherein the codebook in the LTE protocol is a feedback method of such codebook quantization, in fact, the precoding codebook and the channel information quantization code in LTE are used. The meaning is the same. In the following, for the sake of uniformity, the vector can also be viewed as a matrix of dimension 1. In a specific application, the LTE codebook feedback method specifically includes the following aspects:

(1) Feedback granularity of channel information: In the LTE standard, the minimum feedback unit of channel information is subband (Subband) channel information, and one subband is composed of thousands of resource blocks (RBs, RB for short). The RBs are composed of a plurality of resource elements (Resources, RE for short), and the RE is the smallest unit of time-frequency resources in LTE. The LTE resource representation method is used in LTE-A. Several Subbands can be called Multi-Subbands, and many Subbands can be called Broadbands.

(2) Channel information related feedback content: Channel State Information (CSI) feedback includes Channel Quality Indication (CQI) information, PMI, and Rank Indicator (Rank Indicator, RP for short) ). The CSI content we are most concerned about here is PMI information, but both RI and CQI are also part of the channel status information feedback. among them:

CQI is an indicator to measure the quality of downlink channels. In the 36-213 protocol, CQI is represented by integer values from 0 to 15, representing different CQI levels, and different CQIs correspond to their respective modulation modes and code rate (MCS). The RI is used to describe the number of spatially independent channels, corresponding to the Rank of the channel response matrix. In the open-loop spatial multiplexing and closed-loop spatial multiplexing mode, the UE needs to feed back the RI information. In other modes, the RI information is not required to be fed back. The rank of the channel matrix corresponds to the number of layers.

(3) Mechanisms related to channel information feedback: There are two types of feedback methods for uplink channel information in LTE, which are periodic channel information feedback and physical uplink data on the Physical Uplink Control Channel (PUCCH). Shared channel (Physical Uplink Acyclic channel information feedback on the Shared Channel, referred to as PUSCH. PUCCH is a control channel, and the reliability of feedback is high, but its feedback resources are more valuable, and the feedback overhead is strictly limited. The PUSCH can provide more CSI feedback resources, so it can better support single-user spatial multiplexing (SU-MIMO) and multi-user spatial multiplexing (MU-MIMO), but the reliability cannot be guaranteed, and the data transmission is occupied. Resources, there will be some impact on the transmission of data services. The Long Term Evolution Advanced (LTE-A) system, as an evolution standard for LTE, supports larger system bandwidths (up to 100 MHz) and is backward compatible with existing LTE standards. In order to obtain higher cell average spectral efficiency and improve coverage and throughput of the cell edge, LTE-A can support up to 8 antennas on the basis of the existing LTE system, and proposes some codebook feedback. Feedback enhanced technology to better support MU-MIMO. The technique of feedback enhancement is mainly to enhance the feedback accuracy of the codebook and to utilize the temporal correlation of the channel information and/or the frequency domain correlation compression overhead. This technology can improve the spectrum utilization of the evolved International Mobile Telecommunications-Advance (ΙΜΤ-Advance) system and alleviate the shortage of spectrum resources. At the same time, considering that the main application of the 8 antenna will be the case of dual polarization, the design and enhancement of the codebook also need to fully consider the characteristics of the dual polarization channel. The main idea of the feedback technology of the enhanced codebook is that the feedback of the LTE is increased by the feedback of the LTE, and the feedback of the two PMIs is used to represent the state information of the channel, which mainly includes two implementation modes: implementation manner 1, definition Dual codebook and dual PMI feedback, in this way: 1) The structure of the precoding/feedback of a subband consists of two matrices.

2) Each of the two matrices belongs to a separate codebook. The codebook is known in advance by the base station and the UE. The feedback codewords can vary at different times and on different subbands.

3) One matrix represents the properties of the wideband or long-term channel, and the other matrix represents the properties of the determined frequency band or short-term channel. 4) The matrix codebook used is represented in the form of a finite number of matrix sets, and for the UE and the base station, each matrix is known.

5) One of the matrices can be a fixed matrix without feedback. This is equivalent to degenerating to single codebook feedback (possibly in the case of high rank and low rank uncorrelated channels). It can be seen from the above that the feedback of the channel information proposes a structure based on the dual codebook, which can be further described as follows: For one subband or multiple joint subbands that need feedback channel information, the UE feeds back two PMIs to the base station. Information (in some cases, it is not necessary to pass feedback, it is also possible to predefine a PMI to be a fixed value without feedback), which are PMI1 and PMI2 respectively, where PMI1 corresponds to codeword W1 in one codebook C1, and PMI2 corresponds to another codebook. Code word W2 in C2. The base station has the same information of C1 and C2. After receiving PMI1 and PMI2, the corresponding code words W1 and W2 are found from the corresponding codebooks C1 and C2, and W=F (Wl is calculated according to the agreed function rule F). W2) Obtain channel information W. The above dual codebook design criteria is a specific codebook form in LTE-A. In the specific implementation, only the codebook corresponding to W1 and W2 needs to be defined, but there is actually a virtual W corresponding codebook. In the design, more than four performance considerations are considered based on the codebook corresponding to W. In the second implementation manner, a dual codebook equivalent single codebook and dual PMI feedback are defined. In this manner: For Rank = r, r is an integer, which is different from the previous 4Tx codebook in that the double codebook is used. When the price of the single codebook is fed back, the codeword in the corresponding codebook needs to feed back two pieces of feedback to represent the information. The double codebook equivalent codebook can generally be expressed as shown in Table 2 below. Table 2

Here, ₂ is a codeword jointly indicated by and ₂ , and can usually be written as a function form ^^ _{1 2} ;) Only need to determine and ₂ can be. φ _η = e

For example, when r = 1, the definition is as shown in Table 3.

Shown as follows: table 3

This method is actually equivalent to the dual codebook dual PMI. The only difference is that two codebooks C 1 and C2 are no longer defined in this method. Instead, the W code corresponding to the dual codebook and its functional relationship is defined. This, that is, the virtual codebook in the first implementation is actually defined instead of C 1 C2. In LTE-A, in order to better support the performance of MU-MIMO, the feedback precision enhancement technology is used to make the sum of the overheads required to feed back the information of PMI 1 and PMI 2 (also can be understood as the overhead of the codebook corresponding to W). Compared with the overhead of single codebook in LTE, there is a large increase in overhead. In addition, in order to enhance the granularity of feedback, better support for MU-MIMO, PUSCH or PUCCH requires a new feedback mode to feed back each sub- With channel information and CQI information. Since the accuracy of the feedback codebook and the granularity of the feedback are enhanced, the problem is that the overhead is large and the performance is seriously affected. Since the increase of the feedback overhead affects the transmission of normal data services, this is an urgent problem to be solved in the prior art. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method and terminal for feeding back channel information to at least solve the above problems. An aspect of the present invention provides a method for feeding back channel information, including: a terminal feeding back channel state information on a physical uplink shared channel or a physical uplink control channel, where the channel state information includes: rank indication information RI, first codebook Index PMI 1, second codebook index PMI2 and channel quality indicator CQI, in case the total codebook is a double codebook equivalent single codebook form, PMI2 is used to indicate a code in the codebook C _praOT (r) The codebook C _praOT (r) is composed of a partial codeword in a set of codewords corresponding to PMI 1 in the codebook C(r) corresponding to RI of the total codebook. Another aspect of the present invention provides a method for feeding back channel information, including: a terminal feeding back channel state information on a physical uplink shared channel or a physical uplink control channel, where channel state information The method includes: RI, a first codebook index PMI1, a second codebook index PMI2, and a CQI. In a case where the total codebook is in a dual codebook format, PMI2 is used to indicate one codeword in the codebook C _H ( ), wherein The codebook _{ρ is} composed of a partial codeword in the second codebook C ² (r) corresponding to the RI of the total codebook. A further aspect of the present invention provides a method for feeding back channel information, including: the terminal feeding back channel state information on a physical uplink shared channel or a physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1 The second codebook index PMI2 and CQI, the minimum granularity indicated by PMI2 is different from the minimum granularity indicated by the CQI. A further aspect of the present invention provides a terminal, including: a feedback module, configured to feed back channel state information on a physical uplink shared channel or a physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1 The second codebook index PMI2 and CQI, in the case that the total codebook is a double codebook equivalent single codebook form, PMI2 is used to indicate a codeword in the codebook _Cprart (r), codebook C _WSOT W is composed of a partial codeword in a set of codewords corresponding to PMI1 in the codebook C(r) corresponding to RI of the total codebook. A further aspect of the present invention provides a terminal, including: a feedback module, configured to feed back channel state information on a physical uplink shared channel or a physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1 , PMI2 second codebook index and the CQI, in the case where the total code present in the form of a double codebook, PMI2 for indicating one codeword codebook C (r) in ^ _OT, wherein a codebook C ² ή total The codebook corresponds to a partial codeword in the second codebook C ² (r) of the RI. A further aspect of the present invention provides a terminal, including: a feedback module, configured to feed back channel state information on a physical uplink shared channel or a physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1 The second codebook index PMI2 and CQI, the minimum granularity indicated by PMI2 is different from the minimum granularity indicated by the CQI. With the present invention, on the one hand, the fed back PMI2 is used to indicate one codeword in the compressed codebook. Since the number of codewords included in the codebook is compressed, the overhead of PMI2 is correspondingly reduced. On the other hand, PMI2 and The minimum granularity indicated by the CQI can be different, so that the PMI2 and the CQI do not need to maintain the same feedback granularity, and the feedback is more flexible, so that it is not necessary to feed back PMI2 and CQI for each subband, thereby reducing the overhead of feedback and solving the correlation. The codebook accuracy or granularity enhancement feedback in the technology leads to an increase in overhead, reduces the overhead of feedback, and improves the performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, 1 is a schematic diagram of a method for feeding back channel information according to an embodiment of the present invention; FIG. 2 is a structural block diagram of a terminal according to an embodiment of the present invention; FIG. 3 is a feedback channel of Embodiment 6. Schematic diagram of a method of information; FIG. 4 is a schematic diagram of a method of feeding back channel information of Embodiment 7. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. 1 is a schematic diagram of a method for feeding back channel information according to an embodiment of the present invention. As shown in FIG. 1 , in a method, a terminal feeds back channel state information on a physical uplink shared channel or a physical uplink control channel (specifically, The receiving side terminal feeds back to the transmitting side terminal, where the channel state information includes: RI (hereinafter referred to as RI information), first codebook index PMI1 (hereinafter referred to as first PMI index information), and second codebook index PMI2 ( Hereinafter, the second PMI index information) and the CQI (hereinafter referred to as CQI information) are used, and the PMI 2 is used to indicate one of the compressed codebooks (hereinafter also referred to as subcodebooks) corresponding to the RI. When feeding back on the PUSCH or PUCCH, it is necessary to feed back a wideband PMI1 and multiple subband PMI2, and the subband PMI2 takes up a large overhead. Since the design focus and performance guarantee of the LTE-A codebook use a large overhead, actually reducing the partial codeword does not bring about a significant degradation in performance. Therefore, in the above method, the codebook indicated by PMI2 is set to be a compressed codebook (for example, a valid codeword can be selected to construct a subcodebook), so that a large amount of overhead can be reduced when the PMI2 is fed back. It should be noted that, in order to reduce the modification to the existing codebook, a subcodebook used for some transmission modes in the PUSCH or the PUCCH may be constructed based on the codebook in the LTE-A, thereby reducing the feedback PMI2. s expenses'. Preferably, the minimum granularity indicated by ΡΜΙ2 may be different from the minimum granularity indicated by CQI. In this method, ΡΜΙ2 and CQI do not need to maintain the same feedback granularity, and the feedback is more flexible, so that it is not necessary to feed back ΡΜΙ2 and CQI for each sub-band, thereby further reducing the overhead of feedback. The following describes the case of the dual codebook equivalent single codebook and the double codebook: (1) The total codebook is the equivalent single codebook form of the codebook.

ΡΜΙ2 is used to indicate a codeword in the codebook C _praOT (r), wherein the codebook C _praOT (r) is the one corresponding to the PMI1 in the codebook C (r) corresponding to the RI of the total codebook The partial codewords in the set of group codewords are composed. In order to facilitate the PMI2 to indicate a specific codeword, the number of codewords included in the codebook C _praOT (r) may be 1/2 or 1/4 of the number of codewords included in the codebook C (r), of course, only By _{dividing the} partial codewords into C _PUSCH (r), the indication value of PMI2 can be reduced, thereby reducing the overhead used to deliver PMI2. The following describes the configuration of the _subcodebook in the case where the total codebook is a double codebook equivalent single codebook format, in which the second PMI index indicates the codebook C _praOT corresponding to RI=r. (r), one of the set of codewords corresponding to the first PMI index information, C ή is the codebook C (r) corresponding to RI=r in the total codebook C defined in LTE-A A PMI index information is composed of a part of codewords in a set of codewords. Example 1

The double codebook equivalent single codebook C(r) of Rank ² of LTE-A is shown in Table 4 below: Table 4

^^ is a matrix that requires values determined by m and n, m, n are integers, and m, n is related to the first index ^ and the second index ₂ that require feedback.

(1) Considering that each subband feedback saves lbit overhead, you can select 8 codewords from the 16 codewords of C(r) above to form C _praCT? (r). Preferably, it may be that any four codewords are selected from the codeword matrix with an index of 0~7 in the above table, and four codewords are selected from the codeword matrix with an index of 8-15 in the above table. C _pracff (r;). Preferably, it may be that any of the four codewords in the codeword matrix whose index is 0, 2, 4, 6, 8, 10, 12, 14 in the above table, from the above table, the index is 1, 3, The optional four codewords in the codeword matrix of 5, 7, 9, 11, 13, 15 together form C _praCTi (r). From the above table, select 4 codewords in the codeword matrix with Index 0, 1, 4, 5, 8, 9, 12, 13 from the above table, Index is 2, 3, 6, 7, 10, 11 The optional four codewords in the codeword matrix of 14, 14, together form C _praCT? (r;).

(2) Considering that each subband feedback saves 2 bit overhead, you can select 4 code words from the 16 code words of C(r) above to form C _praCT? (r). Preferably, it may be that any two codewords are selected from the codeword matrix with an index of 0~7 in the above table, and two codewords are selected from the codeword matrix with an index of 8-15 in the above table. C _pracff (r;). Preferably, it may be that any two codewords are selected from the codeword matrix with an index of 0~3 in the above table, and two codewords are selected from the codeword matrix with an index of 4-7 in the above table. C _pracff (r).

C _PUSCH (r ) can be as shown in Table 5 below:

That is, 0^(r) is 8 code words whose indices are 0, 3, 4, 7, 8, 11, 12, 15 in C(r). It is also possible that CH (r ) is the other 8 code words remaining in C(r). For example, CH (r ) can be as shown in Table 6 below: Table 6

That is, C H (r) is 8 code words whose index is 0 - 7 in C(r). Of course, it can also be ς

The other 8 codewords remaining in C(r). Alternatively, C _pracff (r) can be as shown in Table 7 below: Table 7

That is, C _PraOT (^ is 8 codewords whose index is 0, 1, 4, 5, 8, 9, 12, 13 in C(r), and can also be CH (r ) as the remaining in C(r) The other 8 code words. Or, C _pracff (r) can be as shown in Table 8 below: Table 8

That is, 0^(r) is 8 code words whose index is 0, 2, 4, 6, 8, 10, 12, 14 in C(r). Of course, C _P (r ) can also be C(r). The remaining 8 codewords in the rest. Alternatively, C _pracff (r) can be as shown in Table 9 below: Table 9

That is, C _PraCT? W is 4 code words whose index is 0, 2, 4, 6 in C(r). Or 0^(r) can also be as shown in Table 10 below: Table 10

That is, 0^^ is 4 code words whose index is 0, 1, 4, 5 in C(r). Or 0^(r) can be as shown in Table 11 below: Table 11

That is, (: _praOT (r) is 4 code words whose index is 0, 3, 4, 7 in C(r). In the above embodiment, the numbering rule of ₂ corresponding code words can be performed without changing the essence of the codebook. The embodiment of the change, extraction example description is mainly based on the feature extraction of the codeword instead of the number feature extraction. (: (r C _praeff (r) complete codeword for arbitrary column exchange, multiplication by constant coefficient or all codewords common The codebook formed after the transformation of the row exchange is equivalent to the codebook before the transformation.

The double codebook equivalent single codebook C(r) of LTE-A Rank3 is shown in Table 12 below: h

0 1 2 3

4 5 6 7

0 - 7 8 9 10 11

12 13 14 15

VV , V „ VV , V „ where fT( ³ ), ,, = i- = i

m ^mm [7A v -v , -v „ ' ^m ' ^mm 724 VV , -v „ where 0" _Vm = [1 W ^{2 32} g 32 _g 6 32 ] ^T , ψ ^) _m „ is a required m, mm "The value of the determined matrix, these parameters are related to the first index ^ and the second index that need to be fed back. (1) Considering that each subband feedback saves lbit overhead, it can be from the 16 code words of C(r) above Select 8 code words to form C _praCT? (r). Preferably, it can be selected from the code matrix of Index 0~3 in the above table, and the index is 4 ~ 7 from the above table. Any two codewords in the codeword matrix, from the code matrix of the index of 8 ~ 11 in the above table, optionally two codewords, from the code matrix of the index of 12 ~ 15 in the above table, optional 2 The codewords together form 0^ (/).

(2) Considering that each subband feedback saves 2 bit overhead, you can select 8 code words from the 16 code words of C(r) above to form C _praCT? (r). Preferably, it may be any one of the codewords in the codeword matrix whose index is 0~3 in the above table, and one of the codeword matrices with the index of 4-7 in the above table, In the above table, any codeword in the codeword matrix with an index of 8 ~ 11 is selected. From the code matrix of the index of 12 ~ 15 in the above table, any one of the codewords is selected to form C _praCT? (r;) . Can be as shown in Table ¹³ below:

12 j.

l\

0 1 2 3

0 - 7 "4i ₁ +4,4i ₁ ,4i ₁ +4 ^43⁄4+1,43⁄4+1,43⁄4+5 4 +5,4 +1,4 +5 j.

l\

4 5 6 7

0 - 7 "4i ₁ + 2,4i ₁ +2,4i ₁ +6 4^+6,4^+2,4^+6 4 +7,4 +3,4 +7 ie C _PraOT (^ is C (r) 8 code words with index 0, 1, 4, 5, 8, 9, 12, 13, of course, can also be (: _praOT (r) is the remaining 8 code words in C(r) Or C _pmrff (r) is shown in Table 14 below: Table 14

That is, 0^ (including 8 code words whose index is 0 1 6 7 8 9 14, 15 in C(r): Alternatively, v CH (r) is the other 8 code words remaining in C(r). 0^ (r) is 8 code words with index 0, 2, 5, 7, 8, 10, 13, 15 in C(r). Of course, v CH (r) can also be left in C(r) The other 8 code words. Or 0^ (r) is 8 code words with index 0, 2, 4, 6, 8, 10, 12, 14 in C(r), or v CH (r) The other 8 codewords remaining in C(r). Or (^

Four codewords with indices 0, 5, 10, and 15 in C(r) and 4 codewords with indices 0, 4, 8, 12 in C(r). The four codewords with indices of 1, 5, 9, 13 in C(r).

13 The index is 4 code words of 2, 6, 10, 14 in C(r).

Four codewords with indices of 3, 7, 11, 15 in C(r).

The four codewords with indices of 0, 8, 13 in C(r). The f-numbering rule can be changed without changing the essence of the codebook. The implementation method of extracting the instance description is mainly based on the feature extraction of the codeword instead of the numbering feature extraction. The codebook formed by the conversion of (r C _praeff (r) completion codeword by arbitrary column exchange, multiplication by constant coefficient or all codewords for row exchange is equivalent to the codebook before conversion. 3

The double codebook equivalent single codebook C(r) of LTE-A Rank4 is shown in Table 15 below: Table 15

Where _=e /2, _{Vm =} [l _e ee ^J is a matrix that is determined by the value of ',', which is related to the first index i and the second index ₂ that require feedback.

(1) Consider saving lbit overhead:

C _PraOT (for 4 code words of C(r) index 0, 2, 4, 6 or other 4 code words. C _PraOT (for C(r) index of 0, 3, 4, 7 of 4 _Codewords or other 4 codewords C _PraOT (4 codewords with index 0, 1, 4, 5 in C(r) or other 4 codewords. Example 4 The double codebook equivalent single codebook ^C ( ^r ) of LTE-ARankl is shown in Table 16 below: Table 16

Where ^(,πηιβϊ ,T

^ is a matrix that requires values determined by m and η, m, n are integers, and m, n is related to the first index j and the second index ₂ that require feedback.

C _Pracff (^ is any index code of 0, 2, 4, 6, 8, 10, 12, 14 in C(r) and the index is 1, 3, 5, 7, 9, 11, 13 a codebook consisting of any four codewords in 15 . Further, it may be C _praOT (for C(r), any two of the codewords with an index of 0, 4, 8, 12, and an index of 2, 6 Any two codewords of 10, 14 are indexed as any two codewords of 1, 5, 9, 13 and the index is a codebook consisting of any two of the 3, 7, 11, 15 codewords. It may also be a codebook composed of 8 code words indexed by IndexO, 1, 2, 3, 8, 9, 10, 11 in C(r), or a codebook composed of other 8 code words. It can also be (: _praOT (r) is a codebook composed of any four codewords in the index 0 to 7 in C(r) and any four codewords in the index 8 to 15. Further may be ( : _praOT (r) is any codeword of 0 to 3 in C(r), any two codewords in index 4~7, index is any 2 codewords in 8~11 The index is a codebook composed of any two code words of 12 to 15.

(2) The total codebook is in the form of a happy code.

PMI2 is used to indicate a codeword in the codebook C _SOT (r), wherein the codebook C _SOT (r) is represented by a partial codeword in the second codebook C ² (r) corresponding to the RI of the total codebook Composition. Among them, in order to facilitate PMI2 The specific codeword is shown, and the number of codewords included in the codebook ( _r ) may be 1/2 or 1/4 of the number of codewords included in the second codebook C ² (r). Of course, only part of the codewords are selected. C^ _OT (r), you can reduce the indication value of PMI2, thus reducing the overhead of passing PMI2. The following describes the configuration of the _subcodebook in the case where the total codebook is in the dual codebook format, in which the second PMI index indicates the time codebook G _raOT (r) of RI=r in the second codebook. One of the codewords, the C^ _OT (r) is formed by a partial codeword in the codebook C ² (r) corresponding to RI=r in the total codebook C defined in LTE-A. Embodiment 5 The LTE-A Rank2 codebook can also be implemented by the following dual codebooks, represented as two codebooks C ¹ (r) and C ² (r), and PMI1 indicates one codeword in C», PMI2 A code word in C ² (r) is indicated, and the two code words collectively represent channel information, such as a product function, by a prescribed function. (W1 corresponds to the codebook) consists of codewords

r ^a i =l^, is the number of columns of the matrix X ^w , b,. is a vector, such as a typical DFT vector (but not limited to this case), there are a total of N basic vectors b. ~ b _N _ , further description is:

B = [b ₀ b, ... " = 0,1,...,N-1

Where N _te is a parameter related to the dimension of the vector, usually refers to the number of transmitting antennas. Ν is an integer power of 2. N _te = 8, N _b = 4, Ν = 32, C _P ^X _USCH contains 16 code words:

X ⁽⁰⁾ = [b. b, ··· b ₃ ] X ⁽¹⁾ = [b ₂ b ₃ ··· b ₅ ] X ⁽²⁾ = [b ₄ b ₅ ··· b

^{X(14) =} [ ^b 2S ^b 29 ··· ^b 3i] ^X(15) = [ ^b 30 ^b 31 ^b l ^b 2 ]

C ² (r) (the codebook corresponding to W2) is composed of m code words, and Rank 2 contains:

Where ,,. is a vector of ^xl, the i-th element is 1 other elements are 0, actually a column

2

The vector selected, when multiplied by the codeword in (^), can be understood as selecting the column in X ^w to construct the codeword in the codebook corresponding to W. The codebook corresponding to w contains any codeword in the left multiplication The codeword obtained by any codeword has m _x X m ₂ codewords, that is, the double codebook equivalent codebook in Embodiment 1. For this codebook equivalent to Embodiment 1, the terminal The RI information r, the first PMI index information, the second PMI index information _2, and the 〇1 information are fed back on the physical uplink shared channel. The second PMI index indicates the time codebook of the RI= _r in the second codebook c _SOT (r One of the codewords, the C _SOT (r) is formed by a partial codeword in the codebook C ² (r) corresponding to RI=r in the total codebook C defined in LTE-A. G „(r) can be constructed according to the method of construction (: _praOT (r) described in Embodiment 1. For the case of other ranks, the same method can also be used. It should be noted that although the above embodiments are The feedback on the physical uplink shared channel is taken as an example. However, the method is also applicable to feedback on the physical uplink control channel, and the subcodebook can use the above. FIG. 2 is a structural block diagram of a terminal according to an embodiment of the present invention. As shown in FIG. 2, the terminal includes: a feedback module 22, configured to be shared in physical uplink. Feedback channel state information on the channel or the physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1, a second codebook index PMI2, and a CQI, where the PMI2 is used to indicate compression corresponding to the RI One codeword in the following codebook. Wherein, in the case that the total codebook is a double codebook equivalent single codebook form, PMI2 is used to indicate one codeword in the codebook C _PraOT (r), and the codebook C _praOT (r) is from the total codebook Corresponding to the codebook C(r) of the RI, a partial codeword in a set of codewords corresponding to the PMI1 is formed. Wherein, in a case where the total codebook is in the form of a dual codebook, the PMI2 is used to indicate a codebook (a codeword in _puseH (), wherein the codebook C _SOT (r) is corresponding to the RI of the total codebook The second codebook C ² (r) is formed by a partial codeword. The embodiment further provides a method for feeding back channel information, including: the terminal feeding back channel state information on a physical uplink shared channel or a physical uplink control channel. The channel state information includes: RI, a first codebook index PMI1, a second codebook index PMI2, and a CQI, where the minimum granularity indicated by the PMI2 is different from the minimum granularity indicated by the CQI. In the method, the PMI2 and The CQI does not need to maintain the same feedback granularity, and the feedback is more flexible, so that it is not necessary to feed back PMI2 and CQI for each subband, thereby reducing the feedback overhead. Preferably, the minimum granularity indicated by PMI2 is the channel of N RBs. Information, the minimum granularity indicated by the CQI is channel information of M RBs, where N and M are positive integers and smaller than the maximum number of RBs in the current bandwidth, and N/M or M/N is an integer greater than 1. The terminal is in physical Uplink shared channel or The RP information r is fed back on the physical uplink control channel, and the first PMI index information, if there are thousands of second PMI index information ₂ and thousands of CQI information, the number of PMI2 and the number of CQIs that the terminal specifically feeds back may be according to the minimum granularity indicated by each. The present embodiment further provides a terminal, including: a feedback module 22, configured to feed back channel state information on a physical uplink shared channel or a physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1, second codebook index PMI2 and CQI, the minimum granularity indicated by the PMI2 is different from the minimum granularity indicated by the CQI. The feedback method using different feedback granularity for CQI and PMI is described by Embodiment 6-7 below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 6 FIG. 3 is a schematic diagram of a method for feeding back channel information according to Embodiment 6, as shown in FIG. 3, PMI2 is fed back for each Subband, and CQI is for 2 Subbands. Feedback A PMI and CQI are fed back to each subband, which saves overhead. In a scenario where CQI does not change much, performance does not cause a significant drop. Embodiment 7 FIG. 4 is a schematic diagram of a method for feeding back channel information according to Embodiment 7. As shown in FIG. 4, CQI is fed back for each Subband, and PMI2 is fed back for 2 Subbands, relative to each sub- The band feeds back a PMI and CQI, which saves overhead. In a scenario where the PMI does not change much, performance does not cause a significant drop. In summary, the solution provided by the embodiment of the present invention can ensure that the MU-MIMO performance is supported on the PUSCH or the PUCCH with reasonable overhead. It should be noted that the steps shown in the flowchart of the accompanying drawings may be performed in a computer system such as a set of computer executable instructions, and, although the logical order is shown in the flowchart, in some cases, The steps shown or described may be performed in an order different from that herein. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device, or they may be separately fabricated into individual integrated circuit modules, or they may be Multiple modules or steps are made into a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the present invention are intended to be included within the scope of the present invention.

Claims

A method for feeding back channel information, comprising:

The terminal feeds back channel state information on the physical uplink shared channel or the physical uplink control channel, where the channel state information includes: rank indication information RI, a first codebook index PMI1, a second codebook index PMI2, and a channel quality indicator CQI, In the case where the total codebook is a double codebook equivalent single codebook form, the PMI2 is used to indicate one codeword in the codebook _CpraOT (r), and the codebook _Cprat (r) is from the total code The codebook C(r) corresponding to the RI is composed of a partial codeword in a set of codewords corresponding to the PMI1.

The method according to claim 1, wherein the number of codewords included in the codebook (r) is 1/2 or 1/4 of the number of codewords included in the codebook C(r).

The method according to claim 1, wherein, in the case where the RI is 2, the partial codeword is determined by one of the following methods:

From the set of codewords { , , l _3⁄4+ ₁ , , w^ _{i h+u} , ₊₂ , ₀ , ^ _23⁄4+2 , , + ₃ ,. , select ⁴ code words, from the code word set {^3⁄4A. , 3⁄4 3⁄4 ₊ u ' w^ ² l _+7n , w^l ₇ · ₊₇ , , . ₊ , _n , · ,, 23⁄4 +,1,, 23⁄4 +, 3, _n 0, w^ 2l +1, ₇ 2 · +3, , 1 } > Medium ¹ select '4 code words;

From the codeword set {k. , l _3⁄4 ₊₁ , , w^ _2W0 , w^ _{W )} , , l _3⁄4 ₊ , o ' 3⁄4 3⁄4 ₊ 3, ' . Select 4 code words in the }, from the code word set

Select 4 code words; from the code word set {^3⁄4,. , _2!ιΛ , w^ _2W0 , ^ _23⁄4 ₊₂ , , , _{3⁄4 3⁄4} _+u ,

Select 4 code words from the 3⁄4 3⁄4 ₊ 3, ' ^3⁄4 ₊₃ }, from the code word set { _u+1 ,. , W^ _{2 +U} , W f (2) ,

" 2 ⁽ i ² ₁ + ⁾ 3,2i ₁ +3,0 ,' W " 2 ⁽ 3⁄4 ²⁾ +3,23⁄4 +3,1 ,' W 2 ⁽²⁾ +1,2 + 2,0 ,, W " 2 ⁽ 3⁄4 ² + ⁾ , i

l,23⁄4 + 2,l ' ^rr 23⁄4 +1,23⁄4 +3,0 ' w " 2 ⁽ 3⁄4 ² + ⁾ l,23⁄4+3,l >:' Select the codeword set { ,., , ' _+U ,

+ ₂ , ₊₃ ,. , all code words in ₊₃ }; Select the codeword set w^> , w^ _2h+Vi ,

2)

2^,2^+3,1 w, (

All codewords in 23⁄4 +1,2 2^+1,2^+3, }; select the codeword set {^ 23⁄4^, 2^,.,. 0,' ^ 23⁄4^,2^,,1,' ^ 2^ + 2,2^ + 2,0 ' , 2 ⁽ ^ ² L+2,,2^.丄+,2,,1, ' 2 ^ ² ,),2^+1,0, ' w 2^,.2^+1,1

3⁄4 3⁄4 ₊ 3, ' ^ +^ } All codewords; Select codeword set {id 2/ ₁ +1,2/ ₁ +1,0, 2^+1,2^+1. w ^rt 2ί ² 'ι + ⁾ 3,2/i+3,( ^rv 2^+3,2^+3,1 w 2 ⁽ i ^T ₁ + ⁾ l,2/ ₁ + 2,0

^ _!l+2 , ' ₊₃ ,. , all code words in _3⁄4+3 };

Select the codeword set { . , 23⁄4+1,23⁄4+1,0 ,' rr- 2 ⁽ i ² ,+ ⁾ 2,2i,+2,( w ^rv 2 ^{ ; ² ₁ + ⁾ 3,2; ₁ +3,( 2ί _] . 2ί ₁ +1,0

(2)

2; ₁ +l,2; ₁ -l-2, ( 2^,2^+3,0 w, 2 ₁ +1,2 ₁ +3. } All code words; Select code word set {ί^ 2^^,2^,1,,^ 2^+1,2^+1,1 ^rv 2^+3,2^+3,1 w ₇ ⁽² lw?l ₇ . ₊₇ , , , ill ² All codewords in }; from the code set { ' , ^2^21^1 ' +1.2/, +1.0, +1,2^+1,1, 2^2,2^ + 2,0 " 2i, +2,2i,+2,l ' w ^rv 2 ^{ ; ² ₁ + ⁾ 3,2; ₁ +3,( , ^W S\, 2, ₊₃ , } Select ² code words, from the code word set { 2^, 2^ +1, 0

Select 2 code words in w ⁽ - ² W ²⁾ , W ⁽²⁾ , W ⁽²⁾ , IV ' ^ u^ ;

From the codeword set {^3⁄4,. , , W^ _2h+U) , ^ _{u +u} } select 2 code words, from the code word set { , ₁₊₂ , W^ _{X2 +2} , F 3⁄4 , , ₁₊ , o ' ^ ^,} Select 2 code words in the middle;

VV whose towel is the value of the PMI1 ² , mm

, φ =e ^j V

4. The method of claim 3, wherein, in the case where the RI is 2, the partial codeword is one of the following:

w 2 ⁽ ι ^Y _χ ,>2ι _χ β , ' r 'r" Ζ ⁽ ι ² ,+ ⁾ Ι.Ζι,+Ι,Ι ,' w " 2 ⁽ i ² ₁ + 2,2i ₁ + 2,0 , ' w " 2 ^{ 3⁄4 ²⁾ +3.2ι, +3.1 ,' w " 2 ^< 3⁄4 ² ,>23⁄4 +1,0 ,, w " 2 ^{ 3⁄4 ² + ⁾ 1,23⁄4 + 2,1 ,' rr 2(l ² ,, ⁾ 2i, +3,0

y ^y 2^,2^,1 ' ^23⁄4+l, 2^+1,0 ' ^rv 2^+2,2^+2,1 ' ^rv 2^+3,2^+3,0 ' 2^ , 2^+1,1 ' 2^+1,2^ + 2,0 ' 2/ ₁ ,2; ₁ +3,l and ¹ W ^vy 2 ⁽ ; ² ! ⁾ +!, 2^+3,0 ; '

"HO 2i, +1,2;, +1,0 '" 2^+2,2^+2,0 ¹ 2 + W'- ^T > _n , w ₇ ⁽² \ 『 ( ² ) and [ ⁽²⁾

The method according to claim 1, wherein, in the case where the RI is 3, the partial codeword is determined by one of the following methods:

Select 2 code words from the code word set { w^ _{AA +4} w^ _{4 h h+4} w^ _4h+4Ah+4 }, from the code word set {ί" _: ⁽²⁾ ί" ⁽²⁾ , ί "( ² ) ί "( ² ) }

2 code words, from the code word set {^3⁄4 ₊₁ ,. , 3⁄4 _3⁄4+u , W^ _2h+2 U select 2 code words, from the code word set { ₊₃₍ W ⁽² } select 2 code words; from the code word set { w^ _{AA +4} w^ Select 1 codeword from _{4 h h+4} w^ _4h+4Ah+4 } and select from the codeword set { Π }

1 codeword selects 1 codeword from the codeword set { I, and selects 1 from the codeword set { _il+3 , _Q , W - ⁽²⁾ ,; 丄, , w ⁾ , W ⁽²⁾ i Codeword;

Where ^ is the PMI1

φ _η =β

6. The method according to claim 1, wherein, in the case where the RI is 3, the partial codeword is one of the following:

w \ w ⁽ - ³⁾ , w ⁽ⁱ⁾

r

+ ² w^) and rr'( ³ ) w ⁽ - ³ , w ⁽³⁾ w ⁽ - ³⁾ ψ θ) and ^ ( ³ ) ; , i ⁽³⁾ and · x +5

, i ⁽³⁾ and · 4^+4,4^4^+4 ' ^4^+4,4^4^ 4^ ,4 4^ +5 ' ^4 ,4^+5,4^+5

, i ⁽³⁾ and · 4^4^+4 4^4^+4,4^+4 4^ ,4 4^ +5 ' ^4 ,4^+5,4^+5

, i ⁽³⁾ and

, i ⁽³⁾ and · ( ³ ) , W ⁽³⁾ , W ⁽³⁾ and ^ ( ³ ) · ( ³ ) , W ⁽³⁾ , W ⁽³⁾ and if ( ³ )

( ³ ), W ⁽³⁾ , W ⁽³⁾

4 and if ( ³ ) ·

4^+4,4^4^+4 ^4 ,4 , ^4^+7,4 ,4^+7 '

, ίν ³ , ίν ³ and ^ ( ³ ) ·

, ίν ³ , ίν ³ and ^ ( ³ ) · ( ³ ) , W ⁽³⁾ , W ⁽³⁾ and if ( ³ ) the method according to claim 1, wherein the RI is 4 In the case, the partial codeword is one of the following:

W ⁽⁴⁾ w ⁴⁾ , w ⁽⁴⁾ and ( ⁴ ) ; w ⁴⁾ w ⁴⁾ , w ⁽⁴⁾ and ( ⁴ ) ; w ⁴⁾ w ⁴⁾ , w ⁽⁴⁾ and ( ⁴ ) ; w ⁴⁾ w ⁴⁾ , w ⁽⁴⁾ and ( ⁴ ) ; w ⁽⁴⁾ , w ⁽⁴⁾ , w ⁽⁴⁾ and ( ⁴ ) The method according to claim 1, wherein, in the case where the RI is 1, the partial codeword is determined by one of the following methods:

⁴ codewords selected from a set of code words u ''_'3, u ⁴ codewords selected;

Select 2 code words from the code word set W^ _{+ l 0} , ₂ , , }, select 2 code words from the code word set, ), ₂ , U, and select 2 from the code word set u ' ^W ^ ' _Codewords , select ² codewords from the codeword set { ₃ , ',3') ₊₃ , ₃ }; from the codeword set { . , 3⁄4, . , U ''} 4 codewords selected from a set of codewords _{_{{) 2,,) 2,}} ,,) 2, 3 ,, ^, 2, υ ⁴ codewords selected;

Select 2 code words from the code word set 3⁄4, from the code word set

Select 2 code words in { , u, , }, select 2 code words from the code word set { ) ₂ , , W^ _{+ v} , , ₂ , , 3 } , from the code word set { ^3,, ^ , ^3,, } select 2 code words;

9. The method according to claim 8, wherein, in the case that the RI is 1, the partial codeword is one of the following:

"23⁄4,0 '"23⁄4,1'"23⁄4,2'"23⁄4,3'"23⁄4 + 2,0 '"23⁄4+2,l'" 23⁄4 + 2,2 ¹ " 23⁄4 + 2,3 '

" 2^+1,0 '"23⁄4+l,l'"23⁄4+l,2'"23⁄4+l,3'"23⁄4+3,0'"23⁄4+3,l'" 23⁄4+3,2 ¹ "23⁄4+3,3 °

10. The method according to claim 1, wherein the minimum granularity indicated by the PMI2 is different from the minimum granularity indicated by the CQI.

11. A method of feeding back channel information, comprising: The terminal feeds back channel state information on the physical uplink shared channel or the physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1, a second codebook index PMI2, and a CQI, where the total codebook is double In the case of a codebook format, the PMI2 is used to indicate a codeword in the codebook _C ^ _SOT W, where the codebook C _SOT (r) is the second code of the total codebook corresponding to the RI The partial codeword in this C ² ( r ) is composed.

12. The method according to claim 11, wherein the number of codewords included in the codebook C _SOT (r) is 1/2 of the number of codewords included in the second codebook C ² (r) Or 1/4.

13. The method according to claim 11, wherein the minimum granularity indicated by the PMI2 is different from the minimum granularity indicated by the CQI.

14. A method of feeding back channel information, comprising:

The terminal feeds back the channel state information on the physical uplink shared channel or the physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1, a second codebook index PMI2, and a CQI, where the PMI2 indicates The minimum granularity is different from the minimum granularity indicated by the CQI.

The method according to claim 14, wherein the minimum granularity indicated by the PMI2 is channel information of N resource blocks RB, and the minimum granularity indicated by the CQI is channel information of M RBs, where, N And M is a positive integer and is smaller than the maximum number of RBs in the current bandwidth, and N/M or M/N is an integer greater than 1.

16. The method according to claim 14, wherein the number of the PMI2 and the number of the CQIs fed back by the terminal are determined according to respective minimum granularities indicated.

17. A terminal, including:

The feedback module is configured to feed back channel state information on the physical uplink shared channel or the physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1, a second codebook index PMI2, and a CQI, _{Where the} codebook is a double codebook equivalent single codebook form, the PMI2 is used to indicate a codeword in the codebook _CpraOT (r), and the codebook _CpraOT (r) is used by the total codebook Corresponding to the codebook C(r) of the RI, a partial codeword in a set of codewords corresponding to the PMI1 is formed.

18. A terminal, including: The feedback module is configured to feed back channel state information on the physical uplink shared channel or the physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1, a second codebook index PMI2, and a CQI, in total Where the codebook is in the form of a dual codebook, the PMI2 is used to indicate a codeword in the codebook C _SOT (r), wherein the codebook C _SOT (r) is corresponding to the codebook C _SOT (r) The partial codeword in the second codebook C ² ( r ) of the RI is formed. A terminal, comprising:

The feedback module is configured to feed back channel state information on the physical uplink shared channel or the physical uplink control channel, where the channel state information includes: RI, a first codebook index PMI1, a second codebook index PMI2, and a CQI, The minimum granularity indicated by PMI2 is different from the minimum granularity indicated by the CQI.