A rank indication determination method, device, terminal and storage medium

Abstract

The embodiments of the present disclosure provide a method, device, terminal and storage medium for determining a rank indication RI. The method includes: determining a set of candidate precoding codebooks that meet the set broadband characteristics according to channel state information; determining a rank indication RI candidate set according to the candidate precoding codebook set; and performing a joint selection of a rank indication RI and a precoding matrix indication PMI according to the rank indication RI candidate set and the candidate precoding codebook set to determine the rank indication RI. According to the RI determination scheme provided by the embodiments of the present disclosure, the range of the candidate precoding codebook set is narrowed down in combination with the broadband characteristics of the channel, and a small range of RI candidate values ​​is further obtained based on the candidate precoding codebook. The RI-PMI joint selection scheme is performed according to the narrowed candidate precoding codebook set and the small range of RI candidate values. This can effectively reduce the computational complexity of the RI-PMI joint selection scheme and improve system performance while ensuring the accuracy of the PMI.

Description

Technical Field

[0001] The present disclosure relates to, but is not limited to, the field of wireless communications, and in particular to a method, device, terminal, and storage medium for determining a rank indication (RI). Background Art

[0002] In some achievable mobile communication schemes, the UE reports channel state information such as RI / PMI / CQI / PTI to the base station to assist the base station in scheduling the UE. LTE R13 and 5G NR introduce CSI-RS resource indication schemes for massive MIMO. The base station uses different beams on different CSI-RS resources for transmission. Then the UE reports the best CRI to the base station, and the RI is calculated based on the best CRI feedback. PMI / CQI / PTI is calculated based on the RI feedback.

[0003] It can be seen that calculating RI and feeding it back is the basis for affecting subsequent transmission performance; therefore, reducing the computational complexity of selecting RI from the entire optional set is an important part of improving the overall transmission performance. Summary of the invention

[0004] The embodiments of the present disclosure provide a rank indication RI determination method, device, terminal and storage medium, which reduce the range of a candidate precoding codebook set in combination with the broadband characteristics of a channel, and further obtain a small range of RI candidate values ​​based on the candidate precoding codebook. A RI-PMI joint selection scheme is performed according to the reduced range of the candidate precoding codebook set and the small range of RI candidate values. Under the premise of ensuring the accuracy of PMI, the computational complexity of the RI-PMI joint selection scheme can be effectively reduced, thereby improving system performance.

[0005] The present disclosure provides a method for determining a rank indication, including:

[0006] Determine, according to the channel state information, a candidate precoding codebook set that meets the set broadband characteristics;

[0007] Determine a rank indication (RI) candidate set according to the candidate precoding codebook set;

[0008] According to the rank indication RI candidate set and the candidate precoding codebook set, a rank indication RI and a precoding matrix indication PMI are jointly selected to determine the rank indication RI.

[0009] The present disclosure also provides a rank indication determination device, including:

[0010] A candidate codebook determination module is configured to determine a set of candidate precoding codebooks that meet a set broadband characteristic according to channel state information;

[0011] A candidate RI determination module, configured to determine a rank indication RI candidate set according to the candidate precoding codebook set;

[0012] The RI determination module is configured to perform a joint selection of a rank indication RI and a precoding matrix indication PMI according to the rank indication RI candidate set and the candidate precoding codebook set to determine the rank indication RI.

[0013] The present disclosure also provides a mobile terminal, including a communication chip, wherein the communication chip is configured to execute:

[0014] To determine a candidate precoding codebook set that meets a set broadband characteristic according to the channel state information;

[0015] Determine a rank indication (RI) candidate set according to the candidate precoding codebook set;

[0016] According to the rank indication RI candidate set and the candidate precoding codebook set, a rank indication RI and a precoding matrix indication PMI are jointly selected to determine the rank indication RI.

[0017] An embodiment of the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the rank indication determination method as described in any embodiment of the present disclosure.

[0018] Other aspects will be apparent upon reading and understanding the drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the solutions of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0020] Figure 1 This is a flow chart of a method for determining a rank indication in an embodiment of the present disclosure;

[0021] Figure 2 This is a flow chart of another rank indication determination method in an embodiment of the present disclosure;

[0022] Figure 3 The figure is a schematic diagram of the structure of a rank indication determination device in an embodiment of the present disclosure.

[0023] The realization of the purpose, functional features and advantages of the present application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] It should be noted that all directional indications in the embodiments of the present disclosure (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0026] In addition, in the present disclosure, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0027] In the present disclosure, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present application scheme can be understood according to specific circumstances.

[0028] In addition, the technical solutions between the various embodiments of the present disclosure can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0029] Before describing the specific embodiments, the abbreviations of the relevant terms involved in the present disclosure are explained as follows:

[0030]

[0031]

[0032] Some feasible solutions use joint estimation method for RI selection:

[0033] RI and PMI are selected to jointly evaluate mutual information MI, and the optimal RI value is determined by the maximum MI value.

[0034] This solution has the best performance, but the implementation is complex. It needs to calculate the MI value of each RI candidate PMI set and compare all combinations to select the optimal RI value. The specific implementation steps are as follows:

[0035] Step 1: Combine the RRC configuration to obtain the optional set of RIs 1≤r≤r max ;

[0036] Step 2: When the rank is r, get the current PMI set and calculate the MI under each PMI k,r K is the index set of PMI, k is an index in K, and the best MI is obtained by comparing the MI values. r .

[0037] Step 3: Compare MI at different ranks r , and get the corresponding RI / PMI.

[0038] {r best ,PMI best}=argmax(MI r ),0≤r <r max .

[0039] It can be seen that although the joint selection of RI and PMI has better performance, the complexity of PMI estimation for each rank is relatively high, especially when there are more codebooks in NR or LTE TM9 mode, the complexity is even higher.

[0040] In some possible implementations, an independent estimation method is adopted: RI selection is independent of PMI, the RI value is determined first, and then the PMI is selected.

[0041] This solution has low complexity and uses the eigenvalue ratio to determine the channel rank information. This solution heavily relies on the threshold value in different scenarios. The specific implementation steps are as follows:

[0042] Step 1: Get the channel estimation matrix The dimension is Q*P*M, where M is the number of samples, Q is the number of receiving antennas, and P is the number of ports. The noise covariance matrix N of the channel is obtained, with the dimension of Q*Q*M, where M is the number of samples. The channel estimate is whitened to obtain H.

[0043] N(n)=LDL H ,

[0044]

[0045] Among them, L is a lower triangular matrix, D is a diagonal matrix, LH is the transposed matrix of L; sqrt() is the square root calculation function, and inv() is the matrix inversion function.

[0046] Step 2: Calculate the channel wideband cross-correlation matrix R.

[0047]

[0048] r max =min(Q,P)

[0049] Where p is the port index, q is the antenna index, and H q,p,n Represents the channel estimation result of the nth sample point.

[0050] Step 3: Perform eigenvalue decomposition on the channel correlation matrix and determine the final RI value r by the eigenvalue ratio best .

[0051]

[0052]

[0053] Among them, β1 is the eigenvalue threshold, and eig() is the function for finding the eigenvalue / eigenvector.

[0054] It is understandable that for NR / LTE systems, the complexity will be greatly reduced by adopting an independent RI selection scheme. However, the premise of the eigenvalue is that the PMI is ideal, which is different from the actual codebook. Especially when the network configuration codebook is limited, the RI selection method based on the eigenvalue is not good at evaluating the real difference between different ranks, and it is also heavily dependent on the scene. The eigenvalue thresholds of different scenes will vary greatly. If the estimated RI value is inaccurate, it will directly affect the robustness and performance of the transmission system.

[0055] The embodiment of the present disclosure provides a rank indication RI determination solution, which reduces the computational complexity without degrading the performance.

[0056] The present disclosure provides a method for determining a rank indication RI. Figure 1 As shown, including:

[0057] Step 110, determining a candidate precoding codebook set that meets a set broadband characteristic according to the channel state information;

[0058] Step 120, determining a rank indication RI candidate set according to the candidate precoding codebook set;

[0059] Step 130: perform a joint selection of a rank indicator RI and a precoding matrix indicator PMI according to the rank indicator RI candidate set and the candidate precoding codebook set to determine the rank indicator RI.

[0060] In some exemplary embodiments, the candidate precoding codebook set is denoted as W set .

[0061] In some exemplary embodiments, the rank indication RI candidate set is denoted as RI set .

[0062] In some exemplary embodiments, step 110 includes:

[0063] When it is determined according to the channel state information that the precoding codebook is a two-stage codebook, a first set number of precoding codebooks are selected from all optional precoding codebooks according to broadband beam characteristics corresponding to the precoding codebook to form the candidate precoding codebook set;

[0064] When it is determined according to the channel state information that the precoding codebook is a primary codebook, determining a preset primary codebook set as the candidate precoding codebook set;

[0065] When it is determined according to the channel state information that no PMI feedback is required, the candidate precoding codebook set is determined according to a preset D matrix, a U matrix, and a preset codebook set when no PMI feedback is required.

[0066] It can be seen that in some exemplary embodiments, when determining the candidate precoding codebook set, selection schemes are determined separately for the two-stage codebook, the one-stage codebook, and the case where no PMI feedback is required, which effectively reduces the subsequent participation in the calculation of channel capacity and the number of precoding codebooks participating in the RI-PMI joint selection, and significantly reduces the computational complexity.

[0067] In some exemplary embodiments, the method further comprises:

[0068] Step 100, obtaining a channel estimation matrix

[0069] Step 102: channel estimation matrix Perform whitening processing to obtain the processed matrix H;

[0070] Step 103, calculate the wideband channel covariance correlation matrix R wb .

[0071] Among them, the channel estimation matrix The dimension is Q*P*M, where M is the number of samples, Q is the number of receiving antennas, and P is the number of ports;

[0072] The channel estimation matrix is ​​calculated according to the following method To perform whitening:

[0073] N(n)=LDL H ,

[0074]

[0075] Where N is the channel noise covariance matrix, H(n) dimension is Q*P, L is the lower triangular matrix, D is the diagonal matrix, L H is the transposed matrix of L; sqrt() is the square root calculation function, and inv() is the matrix inversion function.

[0076] In some exemplary embodiments, the wideband channel covariance correlation matrix R is calculated according to the following method: wb :

[0077]

[0078] Among them, R wb The dimension is P*P, and M is the number of sample points.

[0079] In some exemplary embodiments, step 100 includes:

[0080] According to the channel state information reference signal CSI-RS, the channel estimation matrix is ​​obtained.

[0081] In some exemplary embodiments, when it is determined that the precoding codebook is a two-stage codebook, a first set number of precoding codebooks are selected from all optional precoding codebooks according to broadband beam characteristics corresponding to the precoding codebook to form the candidate precoding codebook set.

[0082] In some exemplary embodiments, TM9 (8 ports or more) and NR (4 ports or more), PMI is composed of two-level codebooks, and the precoding codebook W defined in the specification is W=W1*W2, where W1 represents the broadband beam characteristic and W2 represents the phase difference of the polarized antenna.

[0083] In some exemplary embodiments,

[0084] The dimension of W1 is 2N1N2*B L , W2 dimension is B L *L, L is the number of layers, B L / 2 is the beam used by the codebook, P = 2N1N2.

[0085] Take NR Layer = 1 as an example:

[0086]

[0087] Take NR Layer=2 as an example:

[0088]

[0089] First, assume that Calculate W 1,tmp The broadband receiving power is based on the combination of l and m in the protocol. Generally speaking, l = i 1,1 =0,1,2,…,N1Q1-1; m=i 1,2 =0,1,2,…,N2Q2-1.

[0090] Wherein, N1 and N2 are the horizontal rows and vertical columns of the antenna, respectively, and O1 and O2 are the oversampling multiples in the horizontal and vertical directions, respectively.

[0091]

[0092]

[0093] trace(W 1,tmp,l,m H ·R wb ·W 1,tmp,l,m )=v l,m H ·R 11 ·v l,m +v l,m H ·R 22 ·v l,m

[0094] The beam power is calculated according to the following formula:

[0095] power idx＝(l,m) = trace(W 1,tmp,l,m H ·R wb ·W 1,tmp,l,m );

[0096] Among them, idx is the precoding codebook index, R wb is the wideband channel covariance correlation matrix.

[0097] In some exemplary embodiments, the calculated beam powers are sorted, and the precoding codebook index idxmax corresponding to the first set number of maximum beam powers is obtained, and i 1,1 and i 1,2 .

[0098] In some exemplary embodiments, determining i 1,1 and i 1,2 In some cases, the values ​​of k1 / k2 or i2 are needed to jointly determine the final codebook W1, and then the final W2 is obtained according to the values ​​of i2 or i3. i2 and i3 reflect the selection of W2 phase. Then according to W = W1 * W2, the candidate precoding codebook set W is finally determined. set.

[0099] For example, in the NR system, when rank = 2 and codebookmode = 2, determine i 1,1 and i 1,2 After that, all precoding sets are obtained by taking the value of i2. 1,1 and i 1,2 Next, W1 has 4 choices and W2 has 4 choices.

[0100] Table 1 - Codebook with rank=2, codebookmode=2

[0101]

[0102] For example, when rank = 2 and codebookmode = 1, the beam power is used to determine i 1,1 and i 1,2 After the combination of i2 and k1 / k2, all precoding sets are obtained. In this case, i2 has two combinations, k1 / k2 has up to 4 combinations, and in a certain set of i 1,1 and i 1,2 There are at most 2*4=8 precoding combinations. set .

[0103] Table 2 - Codebook with rank=2, codebookmode=1

[0104]

[0105] It should be noted that the codebooks shown in Table 1 and Table 2 are the contents recorded in 3GPP TS 38.214, and more examples are not recorded in detail here.

[0106] In some exemplary embodiments, when it is determined that the precoding codebook is a two-stage codebook, a first set number of precoding codebooks are selected from all optional precoding codebooks according to the broadband beam characteristics corresponding to the precoding codebook to form the candidate precoding codebook set, including:

[0107] For each precoding codebook W in all optional precoding codebooks, respectively determine the corresponding broadband beam characteristic W1 and the phase difference W2 of the polarized antenna;

[0108] Calculate the beam power corresponding to each broadband beam characteristic W1, and select the broadband beam characteristics W1 with the largest beam power among a first set number;

[0109] According to the broadband beam characteristics W1 of the first set number of maximum beam powers and the phase difference W2 of the corresponding polarized antenna, it is determined that the first set number of precoding codebooks constitute the candidate precoding codebook set.

[0110] In some exemplary embodiments, according to W=W1*W2, W is determined based on the selected W1 and the corresponding W2, and a candidate precoding codebook set W is formed. set .

[0111] In some exemplary embodiments, when the precoding codebook is determined to be a primary codebook, a preset primary codebook set is determined as the candidate precoding codebook set W. set .

[0112] For example, in LTE TM4, TM8 / 9 (2 / 4 ports), the candidate precoding codebook set W set An optional primary codebook defined for the specification.

[0113] For example, in the case of 2 ports in the LTE system, the candidate precoding codebook set W set The codebook is shown in the following table:

[0114] Table 3 - LTE 2-port codebook

[0115]

[0116] For another example, in the case of 4 ports in the LTE system, the candidate precoding codebook set W set The codebook is shown in the following table:

[0117] Table 4 - LTE 4-port codebook

[0118]

[0119] It should be noted that Table 3 in the above example is the codebook recorded in Table 6.3.4.2.3-1 in 3GPP TS 36.211, and Table 4 is the codebook recorded in Table 6.3.4.2.3-2 in 3GPP TS 36.211. For specific meanings, please refer to the specification definition and will not be discussed in detail here.

[0120] In some exemplary embodiments, the candidate precoding codebook set is determined according to a preset D matrix, a U matrix, and a preset codebook set when no PMI feedback is required.

[0121] When it is determined that no PMI feedback is required, the transmitting end performs codebook preprocessing on different carriers so that the performance of each layer is close, and the equivalent codebook is W(i)D(i)U. It is determined that the equivalent codebook W(i)D(i)U constitutes the candidate precoding codebook set W set, D(i) is the preset D matrix, and W(i) is the codebook set when no PMI feedback is required.

[0122] In some exemplary embodiments, the candidate precoding codebook set is determined according to a preset D(0) matrix, a U matrix, and a preset codebook set when no PMI feedback is required.

[0123] For example, for TM3, the D / U matrix used is as follows:

[0124] Table 5-D / U used by TM3

[0125]

[0126] It should be noted that D / U is a codebook component used in the TM3 mode defined in 3GPP TS 36.211, and both the D matrix and the U matrix are matrices of υ×υ dimensions. Table 5 of the above example is the content recorded in Table 6.3.4.2.2-1 in 3GPP TS 36.211.

[0127] When Rank=1, it is SFBC transmission mode; when Rank>=2, due to the cyclic characteristics of DU product, only the combination of D(0)U and precoding W can be considered when determining the candidate precoding codebook set.

[0128] It should be noted that the effect of D / U causes the equivalent channel to be shifted. The SINR of each layer calculated in this way is also a shifted relationship, so the superposition of the channel capacity of each layer is a comprehensive effect. Only by considering the codebook set {W(0)D(0)U, W(1)D(0)U, W(2)D(0)U, W(3)D(0)U}, the average performance of each layer on all REs (resource elements) can be reflected.

[0129] For example, for r=4, D(0)U=[h1,h2,h3,h4], D(1)U=[h2,h3,h4,h1], D(2)U=[h3,h4,h1,h2], D(3)U=[h4,h1,h2,h3]. hi is a 4*1 column vector.

[0130] W set,r ={W(0)D(0)U, W(1)D(0)U, W(2)D(0)U, W(3)D(0)U}.

[0131] That is, the preset D matrix is ​​D(0), and the codebook set when PMI feedback is not required includes: W(0), W(1), W(2), and W(3).

[0132] It can be understood that according to some achievable RI-PMI joint selection schemes, according to Table 6.3.4.2.3-1 or Table 6.3.4.2.3-2 in 3GPP TS 36.211, all codebooks W(i) and D(i) need to be selected to determine the equivalent codebook W(i)D(i)U. The scheme provided by the embodiment of the present disclosure only needs to consider the codebook set {W(0)D(0)U, W(1)D(0)U, W(2)D(0)U, W(3)D(0)U}, that is, only consider the combination of D(0)U and precoding W, which significantly reduces the number of precoding codebooks included in the candidate precoding codebook set.

[0133] In some exemplary embodiments, step 120 includes:

[0134] For each RI value r in all optional RI sets, the following operations are performed: the channel capacity C of the candidate precoding codebook set under the RI value r is calculated, and each channel capacity C is corrected according to the RI value r and the channel capacity penalty factor to obtain the corrected channel capacity

[0135] According to the total corrected channel capacity A second set number of RI values ​​are selected from the entire RI optional set to form the RI candidate set.

[0136] In some exemplary embodiments, the RI values ​​included in the entire RI optional set are determined according to upper layer configuration information.

[0137] In some exemplary embodiments, the RI value r in the entire optional set of RIs satisfies: 0≤r <r max , r max =min(Q,P), Q is the number of receiving antennas, and P is the number of ports.

[0138] In some exemplary embodiments, the calculating the channel capacity C of the candidate precoding codebook set under the RI value r includes:

[0139] Calculating an equivalent signal to interference and noise ratio SINR value of each candidate precoding codebook in the candidate precoding codebook set under the RI value r;

[0140] The channel capacity C corresponding to the RI value r is determined according to the equivalent SI NR value of each of the candidate precoding codebooks.

[0141] In some exemplary embodiments, the equivalent signal to interference and noise ratio SINR value of the candidate precoding codebook is calculated according to the following formula:

[0142]

[0143] Where i is the layer number, idx is the precoding codebook index, R wb is the wideband channel covariance correlation matrix, W set,r is the candidate precoding codebook set corresponding to the RI value r.

[0144] In some exemplary embodiments, when TM3,r=1,

[0145]

[0146] Among them, i is the layer number, R wb is the wideband channel covariance correlation matrix, and I is the identity matrix.

[0147] In some exemplary embodiments, the channel capacity C corresponding to the RI value r is calculated according to the following formula:

[0148]

[0149] in, It indicates the maximum value of the calculation result in the brackets within the range of all idx that can participate in the calculation.

[0150] In some exemplary embodiments, when TM3,r>=1,

[0151]

[0152] Among them, ∑ idx () means that all idx that can participate in the calculation are substituted and added.

[0153] In some exemplary embodiments, the corrected channel capacity is calculated according to the following formula:

[0154]

[0155] Where r is the RI value, C(r) is the channel capacity of the candidate precoding codebook set under the RI value r, g is the channel capacity penalty factor, r max is the maximum RI value among all optional RI sets, 0 <g<1。

[0156] It should be noted that as the rank increases, the inter-layer interference intensifies. Therefore, if the channel capacity is close, it is usually inclined to choose a low rank to obtain more robust performance. Therefore, the penalty measure of increasing the rank is used. The penalty factor is g, and the penalty increases with the increase of the rank.

[0157] In some exemplary embodiments, the channel capacity after all corrections Selecting a set number of rank indication RI values ​​from all optional sets of the rank indication RI to form the rank indication RI candidate set includes:

[0158] Determine the total corrected channel capacity and a rank indication RI value corresponding to the maximum value;

[0159] Corrected channel capacity corresponding to the adjacent rank indication RI value According to the principle of large value priority, a second set number of consecutive rank indication RI values ​​are selected from all optional sets of the rank indication RI to form the rank indication RI candidate set;

[0160] The rank indication RI candidate set includes the rank indication RI value corresponding to the maximum value, and the adjacent rank indication RI values ​​are rank indication RI values ​​adjacent to the rank indication RI value corresponding to the maximum value.

[0161] In some exemplary embodiments, the second set number is S, and the modified channel capacity is The RI value corresponding to the maximum value in is RIx, then S RI values ​​(including RIx) are selected from the entire optional set of rank indication RI, and these S RI values ​​are continuous; S continuous RI values ​​constitute an RI value sequence. Among them, when S RI values ​​(including RIx) are selected from the entire optional set of rank indication RI, the corrected channel capacity corresponding to the adjacent RI values ​​is The larger value is selected first, that is, when there are multiple possible RI value sequences, the corrected channel capacity corresponding to the RI value close to RIx is selected first. Finally, the selected S RI values ​​(including RIx) constitute the RI candidate set RI set for

[0162] In some exemplary embodiments, the second set number = 3 or 2; or other set numbers.

[0163] For example, the second set number = 2, the total selectable set of RI is {1, 2, 3, 4, 5}, and the total corrected channel capacity is determined as The maximum value in the RI value corresponds to 3, then the RI value sequence including RI value 3 is: 2-3 or 3-4, and the corrected channel capacity corresponding to RI value = 2 The corrected channel capacity is greater than RI value = 4 According to the "corrected channel capacity corresponding to the adjacent rank indication RI value The “large value first principle” determines that the RI candidate set is {2,3}.

[0164] For example, the second set number = 3, the total selectable set of RI is {1, 2, 3, 4, 5}, and the total corrected channel capacity is determined as The maximum RI value in corresponds to 3. The possible continuous RI value sequences are 1-2-3, 2-3-4, or 3-4-5. The RI values ​​adjacent to 3 are 2 and 4. Then, the modified channel capacity corresponding to RI value = 2 is compared. Corrected channel capacity corresponding to RI value = 4 If RI value = 2, the corresponding corrected channel capacity The corrected channel capacity is greater than RI value = 4 Then, we further compare the corrected channel capacity corresponding to RI value = 1 in 1-2-3 and 2-3-4. Corrected channel capacity corresponding to RI value = 4 If the RI value = 1, the corresponding corrected channel capacity The corrected channel capacity is greater than RI value = 4 Then the RI candidate set is determined to be {1, 2, 3}; if the RI value = 1, the corresponding corrected channel capacity is Less than or equal to the corrected channel capacity corresponding to RI value = 4 Then the RI candidate set is determined to be {2, 3, 4}.

[0165] If RI value = 2, the corresponding corrected channel capacity Less than or equal to the corrected channel capacity corresponding to RI value = 4 Then, we further compare the corrected channel capacity corresponding to RI value = 2 in 2-3-4 and 3-4-5. Corrected channel capacity corresponding to RI value = 5 If the RI value = 2, the corresponding corrected channel capacity The corrected channel capacity corresponding to RI value = 5 is greater than Then the RI candidate set is determined to be {2, 3, 4}; if the RI value = 2, the corresponding corrected channel capacity is Less than or equal to the corrected channel capacity corresponding to RI value = 5 Then the RI candidate set is determined to be {3, 4, 5}.

[0166] For example, the second set number = 3, the total selectable set of RI is {1, 2, 3, 4, 5}, and the total corrected channel capacity is determined as The RI value corresponding to the maximum value in is 5, and the possible continuous RI value sequence is 3-4-5, so the RI candidate set is determined to be {3,4,5}.

[0167] It can be understood that the corrected channel capacity corresponding to the adjacent RI value is The principle of large value priority indicates that when determining a continuous RI value sequence including the rank indication RI value corresponding to the maximum value, the corresponding corrected channel capacity is preferentially selected according to the distance of each RI value from the rank indication RI value corresponding to the maximum value, from near to far. The RI value of the rank indication RI value corresponding to the maximum value having a larger numerical value is adjacent to the rank indication RI value.

[0168] In some exemplary embodiments, step 130 includes:

[0169] Under the RI candidate set, based on the candidate precoding codebook set, jointly select RI and PMI to calculate all MI values;

[0170] The RI value corresponding to the largest MI value is selected as the RI, that is, the final RI reporting value.

[0171] That is, in the RI candidate set RI set Next, based on the candidate precoding codebook set W set , calculate the value, k is the candidate precoding codebook set W set The precoding codebook index in the MI value is compared to get the best The final reported RI is determined according to the following method:

[0172]

[0173] It can be understood that under the RI candidate set, the codebook index in the candidate precoding codebook set that meets the set broadband characteristics determined in step 110 is used as the input for the joint selection of the PMI and RI of the subsequent subband, and the joint selection of RI and PMI is performed in the subband domain, and the MI value is calculated to finally determine the RI reporting value.

[0174] The RI determination scheme proposed in the embodiment of the present disclosure takes into account the broadband characteristics of the channel and calculates the channel capacity under broadband in combination with the precoding matrix, obtains a relatively accurate set of candidate RIs, and outputs the precoding codebook index that characterizes the broadband characteristics to the subsequent subband domain for joint selection of PMI and RI, thereby ensuring the accuracy of RI while reducing the computational complexity.

[0175] The present disclosure also provides a method for determining RI. Figure 2 As shown, including:

[0176] Step 210, channel estimation whitening;

[0177] Step 220, calculating the wideband channel covariance matrix;

[0178] Step 230, determining a candidate precoding codebook set that meets the set broadband characteristics;

[0179] Step 240, calculating the equivalent SINR value under the candidate precoding codebook set under each RI value r;

[0180] Step 250, calculating the channel capacity C corresponding to each RI value r;

[0181] Step 260, correct the capacity C of each channel to obtain the corrected channel capacity

[0182] Step 270, corrected channel capacity Sorting, determining the RI candidate set;

[0183] Step 280, performing RI-PMI joint selection: under the RI candidate set, based on the codebook index in the candidate precoding codebook set as the input for the joint selection of PMI and RI of the subsequent subband, perform the joint selection of RI and PMI in the subband domain, and calculate the MI value;

[0184] Step 290: Select the RI value corresponding to the maximum MI value as the final RI reporting value.

[0185] Wherein, step 210 includes:

[0186] Get the channel estimation matrix The dimension is Q*P*M, where M is the number of samples, Q is the number of receiving antennas, and P is the number of ports. The noise covariance matrix N of the channel is obtained, with the dimension of Q*Q*M, where M is the number of samples. The channel estimate is whitened to obtain H.

[0187] N(n)=LDL H ,

[0188]

[0189] In step 220, the wideband channel covariance correlation matrix R is calculated according to the following method: wb :

[0190]

[0191] Step 230 is divided into the following three cases:

[0192] Step 230-1, when it is determined that the precoding codebook is a two-stage codebook, a first set number of precoding codebooks are selected from all optional precoding codebooks according to the broadband beam characteristics corresponding to the precoding codebook to form the candidate precoding codebook set, including:

[0193] For each precoding codebook W in all optional precoding codebooks, respectively determine the corresponding broadband beam characteristic W1 and the phase difference W2 of the polarized antenna;

[0194] Calculate the beam power corresponding to each broadband beam characteristic W1, and select the broadband beam characteristics W1 with the largest beam power among a first set number;

[0195] According to W=W1*W2, based on the broadband beam characteristics W1 with the largest beam power of the first set number and the phase difference W2 of the corresponding polarized antenna, it is determined that the first set number of precoding codebooks constitute the candidate precoding codebook set W set .

[0196] The beam power corresponding to each broadband beam characteristic W1 is calculated according to the following method:

[0197] power idx＝(l,m) = trace(W 1,tmp,l,m H ·R wb ·W 1,tmp,l,m );

[0198] Among them, trace(W 1,tmp,l,m H ·R wb ·W 1,tmp,l,m )=v l,m H ·R 11 ·v l,m +v l,m H ·R 22 ·v l,m ;

[0199]

[0200]

[0201] Step 230-2: When the precoding codebook is determined to be a primary codebook, a preset primary codebook set is determined as the candidate precoding codebook set W. set .

[0202] Step 230-3: When it is determined that PMI feedback is not required, the candidate precoding codebook set is determined according to the preset D(0) matrix, the U matrix, and the preset codebook set when PMI feedback is not required.

[0203] Step 240, respectively calculate the equivalent signal to interference and noise ratio SINR value of each candidate precoding codebook in the candidate precoding codebook set under each RI value r included in the entire RI optional set:

[0204]

[0205] Step 250: Determine the channel capacity C corresponding to the RI value r according to the equivalent SINR value of each candidate precoding codebook:

[0206]

[0207] Step 260, calculate the corrected channel capacity according to the following formula

[0208]

[0209] Where r is the RI value, C(r) is the channel capacity of the candidate precoding codebook set under the RI value r, g is the channel capacity penalty factor, r max is the maximum RI value among all optional RI sets, 0 <g<1。

[0210] In some exemplary embodiments, r max =min(P,Q).

[0211] Step 270, Sort and determine the largest The corresponding RI values ​​are selected including the maximum The second set number S of consecutive RI values ​​corresponding to the RI value constitutes an RI candidate set, and the final selected RI candidate set is defined as

[0212] Step 290: Select the RI value corresponding to the maximum MI value as the final RI reporting value, that is,

[0213]

[0214] Among them, in step 270, the corrected channel capacity corresponding to the adjacent rank indication RI value is According to the principle of large value priority, a second set number S of continuous rank indication RI values ​​are selected from all optional sets of the rank indication RI to form the rank indication RI candidate set.

[0215] The present disclosure also provides a rank indication determination device, such as Figure 3 As shown, including:

[0216] The candidate codebook determination module 310 is configured to determine a set of candidate precoding codebooks that meet the set broadband characteristics according to the channel state information;

[0217] The candidate RI determination module 320 is configured to determine a rank indication RI candidate set according to the candidate precoding codebook set;

[0218] The RI determination module 330 is configured to perform a joint selection of a rank indication RI and a precoding matrix indication PMI according to the rank indication RI candidate set and the candidate precoding codebook set to determine the rank indication RI.

[0219] The present disclosure also provides a mobile terminal, including a communication chip, wherein the communication chip is configured to execute:

[0220] To determine a candidate precoding codebook set that meets a set broadband characteristic according to the channel state information;

[0221] Determine a rank indication (RI) candidate set according to the candidate precoding codebook set;

[0222] According to the rank indication RI candidate set and the candidate precoding codebook set, a rank indication RI and a precoding matrix indication PMI are jointly selected to determine the rank indication RI.

[0223] The present disclosure also provides an electronic device, including:

[0224] one or more processors;

[0225] a storage device for storing one or more programs,

[0226] When the one or more programs are executed by the one or more processors, the one or more processors implement the rank indication determination method as described in any embodiment of the present disclosure.

[0227] An embodiment of the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the rank indication determination method as described in any embodiment of the present disclosure.

[0228] It can be seen that the rank indication determination scheme provided by the embodiment of the present disclosure takes into account the broadband characteristics of the channel and combines the precoding matrix to calculate the channel capacity under broadband, obtains a relatively accurate RI candidate set with a smaller range, and outputs the precoding index representing the broadband characteristics for the subsequent joint selection of RI and PMI, thereby ensuring the accuracy of RI while reducing the computational complexity. In some exemplary embodiments, the candidate precoding codebook sets representing the broadband codebook characteristics are determined respectively according to the codebook characteristics, which improves the overall execution efficiency of the RI selection determination scheme.

[0229] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are 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 tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain 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 may include any information delivery media.

[0230] The above description is only a preferred embodiment of the present application scheme, and does not limit the patent scope of the present application. All equivalent structural changes made based on the concept of the present application scheme and the contents of the present application specification and drawings, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A rank indication determination method, characterized in that: include: Determine, according to the channel state information, a candidate precoding codebook set that meets the set broadband characteristics; Determine a rank indication (RI) candidate set according to the candidate precoding codebook set; According to the rank indication RI candidate set and the candidate precoding codebook set, jointly select a rank indication RI and a precoding matrix indication PMI to determine the rank indication RI; The step of determining, according to the channel state information, a candidate precoding codebook set that meets the set broadband characteristics includes: When it is determined according to the channel state information that the precoding codebook is a two-stage codebook, a first set number of precoding codebooks are selected from all optional precoding codebooks according to broadband beam characteristics corresponding to the precoding codebook to form the candidate precoding codebook set; When it is determined according to the channel state information that the precoding codebook is a primary codebook, determining a preset primary codebook set as the candidate precoding codebook set; When it is determined according to the channel state information that no PMI feedback is required, the candidate precoding codebook set is determined according to a preset D matrix, a U matrix, and a preset codebook set when no PMI feedback is required.

2. The method according to claim 1, characterized in that The selecting a first set number of precoding codebooks from all optional precoding codebooks according to the broadband beam characteristics corresponding to the precoding codebooks includes: For each precoding codebook W in all optional precoding codebooks, respectively determine the corresponding broadband beam characteristic W1 and the phase difference W2 of the polarized antenna; Calculate the beam power corresponding to each broadband beam characteristic W1, and select a first set number of broadband beam characteristics W1 with the largest beam power; According to the broadband beam characteristics W1 of the first set number of maximum beam powers and the phase difference W2 of the corresponding polarized antenna, it is determined that the first set number of precoding codebooks constitute the candidate precoding codebook set.

3. The method according to any one of claims 1 to 2, characterized in that: The determining, according to the candidate precoding codebook set, a rank indication RI candidate set includes: For each rank indication RI value r in all optional sets of rank indication RI, the following operations are performed respectively: the channel capacity C of the candidate precoding codebook set under the rank indication RI value r is calculated, and each channel capacity C is corrected according to the rank indication RI value r and the channel capacity penalty factor to obtain the corrected channel capacity According to the total corrected channel capacity A second set number of rank indication RI values ​​are selected from all optional sets of the rank indication RI to form the rank indication RI candidate set.

4. The method according to claim 3, characterized in that The calculating the channel capacity C of the candidate precoding codebook set under the rank indication RI value r includes: Calculating an equivalent signal to interference and noise ratio SINR value of each candidate precoding codebook in the candidate precoding codebook set under the rank indication RI value r; The channel capacity C corresponding to the rank indication RI value r is determined according to the equivalent SINR value of each candidate precoding codebook.

5. The method according to claim 3, characterized in that The corrected channel capacity is calculated according to the following formula Where r is the rank indicator RI value, C(r) is the channel capacity of the candidate precoding codebook set under the rank indicator RI value r, g is the channel capacity penalty factor, r max is the maximum rank indication RI value among all optional sets of rank indication RI, 0 <g<1。 6. The method according to claim 3, characterized in that The channel capacity according to all corrections Selecting a second set number of rank indication RI values ​​from all optional sets of the rank indication RI to form the rank indication RI candidate set includes: Determine the total corrected channel capacity and a rank indication RI value corresponding to the maximum value; Corrected channel capacity corresponding to the adjacent rank indication RI value According to the principle of large value priority, a second set number of consecutive rank indication RI values ​​are selected from all optional sets of the rank indication RI to form the rank indication RI candidate set; The rank indication RI candidate set includes the rank indication RI value corresponding to the maximum value, and the adjacent rank indication RI values ​​are rank indication RI values ​​adjacent to the rank indication RI value corresponding to the maximum value.

7. A rank indication determination device, characterized in that: include: A candidate codebook determination module is configured to determine a set of candidate precoding codebooks that meet a set broadband characteristic according to channel state information; A candidate RI determination module, configured to determine a rank indication RI candidate set according to the candidate precoding codebook set; An RI determination module is configured to perform a joint selection of a rank indication RI and a precoding matrix indication PMI according to the rank indication RI candidate set and the candidate precoding codebook set to determine the rank indication RI; The candidate codebook determination module determines a set of candidate precoding codebooks that meet the set broadband characteristics according to the channel state information, including: When it is determined according to the channel state information that the precoding codebook is a two-stage codebook, a first set number of precoding codebooks are selected from all optional precoding codebooks according to broadband beam characteristics corresponding to the precoding codebook to form the candidate precoding codebook set; When it is determined according to the channel state information that the precoding codebook is a primary codebook, determining a preset primary codebook set as the candidate precoding codebook set; When it is determined according to the channel state information that no PMI feedback is required, the candidate precoding codebook set is determined according to a preset D matrix, a U matrix, and a preset codebook set when no PMI feedback is required.

8. A mobile terminal, characterized in that: A communication chip is included, wherein the communication chip is configured to perform: Determine, according to the channel state information, a candidate precoding codebook set that meets the set broadband characteristics; Determine a rank indication (RI) candidate set according to the candidate precoding codebook set; According to the rank indication RI candidate set and the candidate precoding codebook set, jointly select a rank indication RI and a precoding matrix indication PMI to determine the rank indication RI; The step of determining, according to the channel state information, a candidate precoding codebook set that meets the set broadband characteristics includes: When it is determined according to the channel state information that the precoding codebook is a two-stage codebook, a first set number of precoding codebooks are selected from all optional precoding codebooks according to broadband beam characteristics corresponding to the precoding codebook to form the candidate precoding codebook set; When it is determined according to the channel state information that the precoding codebook is a primary codebook, determining a preset primary codebook set as the candidate precoding codebook set; When it is determined according to the channel state information that no PMI feedback is required, the candidate precoding codebook set is determined according to a preset D matrix, a U matrix, and a preset codebook set when no PMI feedback is required.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the rank indication determination method according to any one of claims 1 to 6 is implemented.

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