[0023] In order to solve the problem that the codebook shared by the transmitting end and the receiving end in the beam forming system in the prior art may cause the beam used by the transmitting end to be mismatched with the current channel, and the performance of the system deteriorates, the embodiment of the present invention provides a resistance The codebook selection method for feedback error will be described in detail below with reference to the drawings and embodiments.
[0024] According to an embodiment of the present invention, a method for selecting a codebook against feedback errors, the codebook includes: at least two codewords, and a sequence number corresponding to each codeword; the flow of the method is as follows image 3 As shown, specifically including:
[0025] 301. Compile a codebook with at least two correspondences between codewords and serial numbers.
[0026] The codebook includes: at least two codewords, a sequence number equal to the number of codewords, and the corresponding relationship between the codewords and the sequence numbers. One codebook is compiled for a correspondence relationship, and at least two codebooks are compiled.
[0027] 302. Obtain the transmission error parameter value of each codebook.
[0028] In step 302, the transmission error parameter value may include: a selection probability value, an error probability value, and a similarity value;
[0029] The selection probability value is the probability that each codeword is selected by the receiving end; the selection probability value is large, indicating that the probability of the codeword being selected by the receiving end is high; on the contrary, the selection probability value is small, indicating that the codeword is received The chance of end selection is low;
[0030] The error probability value is the probability that the receiving end sends a sequence number corresponding to a codeword, and the sending end obtains the sequence number corresponding to another codeword; the error probability value is large, indicating that the receiving end sends a sequence number corresponding to a codeword, the sending end The probability of obtaining a sequence number corresponding to another codeword is high; on the contrary, the error probability value is small, indicating that the receiving end sends a sequence number corresponding to one codeword, and the sending end has a low probability of obtaining a sequence number corresponding to another codeword;
[0031] The similarity value is the degree of similarity between the two codewords when the receiving end sends a sequence number corresponding to one codeword, and the sending end obtains the sequence number corresponding to another codeword.
[0032] The small similarity value indicates that the similarity between the two codewords is high; on the contrary, the large similarity value indicates that the similarity between the two codewords is low.
[0033] In step 302, the step of calculating the transmission error parameter value of each codebook includes:
[0034] Calculate the product of the selection probability value of each codeword and the error probability value and the similarity value in each codebook, as the transmission error parameter value of the codeword;
[0035] Specifically, the expression formula of the transmission error parameter value is: d c *T*P, where d c Represents the similarity value, T represents the error probability value, and P represents the selection probability value.
[0036] As a preference, d c * T * P = Σ k = 1 K Σ j = 1 K d k，j *T k，j *P k , Where T k，j Indicates the probability that the receiving end sends a sequence number of k and the sending end gets a sequence number of j, d k，j Indicates the degree of similarity between the codeword with sequence number k and the codeword with sequence number j when the receiving end sends sequence number k and the sending end gets sequence number j, P k Indicates the probability of selecting the sequence number k, and K represents the maximum value of the sequence number in the codebook.
[0037] Take the sum of the transmission error parameter values of all codewords as the transmission error parameter value of the codebook:
[0038] Generally, a codebook includes several codewords, and the transmission error parameter value of a codebook is the sum of the transmission error parameter values of all codewords in the codebook.
[0039] 303. Select the codebook with the smallest transmission error parameter value as the codebook shared by the signal sending end and the receiving end.
[0040] In the method for selecting a codebook against feedback errors provided by the embodiment of the present invention, by compiling codebooks with various corresponding relationships between codewords and serial numbers, the transmission error parameter value of each codebook is obtained, and the feedback error resistance of each codebook can be evaluated. Ability; then select the codebook with the smallest transmission error parameter value as the new codebook shared by the signal transmitter and receiver. In this way, the new codebook obtained will be the one with the strongest ability to resist feedback errors among the codebooks. Applying the new codebook on the transmitter and receiver can make the beam used by the transmitter match the current channel as much as possible, ensuring The transmission performance of the system.
[0041] Those skilled in the art can understand that, when implementing the present invention, selecting the codebook with the smallest transmission error parameter value as the codebook shared by the signal transmitting end and the receiving end is only an alternative and optimal solution, and not necessarily Select the codebook with the smallest transmission error parameter value, or select the codebook with the second or smaller transmission error parameter value. Therefore, a suitable codebook can be selected by transmitting error parameter values according to the characteristics of the network system or the actual needs of operators.
[0042] A preferred embodiment of this method is described in detail below:
[0043]As shown in Table 1, suppose the codebook to be used for encoding includes 8 codewords (the first column of Table 1), corresponding to 8 sequence numbers (the second column of Table 1), and each sequence number is transmitted from the receiving end to the sending end. The end needs to occupy 3 bits of resources (the third column of Table 1).
[0044] Codeword
[0045] Table 1
[0046] In this embodiment, the error probability value T is the error propagation probability value of the binary symmetric channel, and the expression formula is: T k，j = P D(k，j) *(1-p) 3-D(k，j) , Where T k，j Represents the probability that the receiving end sends a sequence number of k and the sending end gets a sequence number of j, p is the probability of a 1-bit error (it can be obtained through simulation experiments, actual measurement, or theoretical analysis), D(k,j) represents the sequence number k and the sequence number The Hamming distance between the binary bit values corresponding to j (the number of characters that need to be replaced to change a character string into another character string);
[0047] Similarity value d k，1 Take the chord distance d between code word k and code word j c (c k , C 1 ), the expression formula is: d c ( c k , c j ) = 1 - | c k H c j | 2 . Among them, the letter H indicates that the matrix c k The conjugate transpose operation.
[0048] First, the various correspondences between codewords and serial numbers are exhaustively listed, and the various correspondences of all codewords are respectively compiled into a codebook.
[0049] In this embodiment, because the number of code words is small, even if an exhaustive method is used, the amount of calculation is not too large. For codebooks with more codewords, some sub-optimal algorithms can be used to reduce the amount of calculation, such as binary switching algorithm or simulated annealing algorithm.
[0050] To obtain the transmission error parameter value of each codebook, the following calculation formula can be used:
[0051] d c * T * P = Σ k = 1 K Σ j = 1 K d c ( c k , c j ) * T k , j * P k ;
[0052] among them, d c ( c k , c j ) = 1 - | c k H c j | 2 ;
[0053] T k，j = P D(k，j) *(1-p) 3-D(k，j) , Since p is usually very small in practical applications, the probability of multi-bit errors can be ignored, so the error propagation probability can be approximated as
[0054] T k , j ≈ ( 1 - p ) 3 , D ( k , j ) = 0 , p ( 1 - p ) 2 , D ( k , j ) = 1 , 0 , D ( k , j ) = 2,3 ,
[0055] Through the simulation experiment, it can be known that each codeword is selected by the receiving end with approximately equal probability, so
[0056] P k ≈ 1 8 , k = 1,2 , · · · , 8 .
[0057] In this way, by solving the transmission error parameters for each codeword and its corresponding serial number, and then taking the sum of all codewords and their corresponding serial number transmission error parameters, the transmission error parameter of each codebook can be obtained;
[0058] The codebook with the smallest transmission error parameter value is used as the codebook shared by the signal transmitter and receiver. This codebook is the codebook with the strongest feedback error resistance among the codebooks. The new codebook is shown in Table 2.
[0059] Codeword Code word number c 1 =[-0.3427+j0.9161,0.0498+j0.2019] T 1 c 2 =[0.1049+j0.6820,0.6537+j0.3106] T 2 c 3 =[-0.7457+j0.1181, -0.4553-j0.4719] T 3 c 4 =[-0.0347-j0.2716,0.0935-j0.9572] T 4 c 5 =[-0.7983+j0.3232,0.5000+j0.0906] T 5 c 6 =[-0.2065+j0.3371,0.9166+j0.0600] T 6 c 7 =[0.8393-j0.2939, -0.1677+j0.4256] T 7 c 8 =[0.3478-j0.3351, 0.2584-j0.8366] T 8
[0060] Table 2
[0061] The change of the corresponding relationship between the codewords of the new and old codebooks and serial numbers is shown in Table 3
[0062] Codeword Code word number Serial number after transformation c 1 =[0.8393-j0.2939, -0.1677+j0.4256] T 1 7 c 2 =[-0.3427+j0.9161,0.0498+j0.2019] T 2 1 c 3 =[-0.2065+j0.3371,0.9166+j0.0600] T 3 6 c 4 =[0.3478-j0.3351, 0.2584-j0.8366] T 4 8 c 5 =[0.1049+j0.6820,0.6537+j0.3106] T 5 2 c 6 =[0.0347-j0.2716,0.0935-j0.9572] T 6 4 c 7 =[-0.7457+j0.1181, -0.4553-j0.4719] T 7 3 c 8 =[-0.7983+j0.3232,0.5000+j0.0906] T 8 5
[0063] table 3
[0064] Figure 5 with Figure 6 Is the simulation result of applying the codebook to the transmitter and receiver of the beamforming system, from Figure 5 It can be seen that the signal-to-noise ratio gain curve (the upper curve in the figure) after using the new codebook is significantly better than the signal-to-noise ratio gain curve of the original codebook (the lower curve in the figure). From Figure 6 It can be seen that the bit error rate curve (the lower curve in the figure) after using the new codebook is significantly better than the bit error rate curve of the original codebook (the upper curve in the figure). This simulation result can illustrate the enhancement of the system's ability to resist feedback errors in the embodiment of the present invention.
[0065] In the method for selecting a codebook against feedback errors provided by the embodiment of the present invention, by compiling codebooks with various corresponding relationships between codewords and serial numbers, the transmission error parameter value of each codebook can be obtained, and the feedback error resistance of each codebook can be evaluated. Ability; then select the codebook with the smallest transmission error parameter value as the new codebook shared by the signal transmitter and receiver. In this way, the new codebook obtained will be the one with the strongest ability to resist feedback errors among the codebooks. Applying the new codebook at the transmitting end and the receiving end can make the beam used by the transmitting end match the current channel as much as possible, ensuring The transmission performance of the system.
[0066] In addition, the method for selecting a codebook against feedback errors provided by the embodiment of the present invention belongs to a precoding method, and does not occupy the resources of the transmitting end and the receiving end of the beamforming system; when compiling the codebook corresponding to the codeword and the serial number, the code The various correspondences between words and serial numbers are exhaustively listed, or only part of the correspondences can be listed, so that the workload of the system can be flexibly arranged, which is conducive to making full use of system resources.
[0067] The embodiment of the present invention also provides a codebook selection device that is resistant to feedback errors. The codebook includes: at least two codewords and a sequence number corresponding to each codeword; the device is such as Figure 4 Shown, including:
[0068] The codebook generation module is used to compile codebooks with at least two correspondences between codewords and serial numbers;
[0069] The error acquisition module is used to acquire the transmission error parameter value of each codebook;
[0070] The codebook optimization module is used to select the codebook with the smallest transmission error parameter value as the codebook shared by the signal sending end and the receiving end.
[0071] Wherein, the transmission error parameter value includes: a selection probability value, an error probability value, and a similarity value;
[0072] The selection probability value is the probability that each codeword is selected by the receiving end;
[0073] The error probability is the probability that the receiving end sends a sequence number corresponding to one codeword, and the sending end obtains the sequence number corresponding to another codeword;
[0074] The similarity value is the degree of similarity between the two codewords when the receiving end sends a sequence number corresponding to one codeword, and the sending end obtains the sequence number corresponding to another codeword.
[0075] If the selection probability value is large, it indicates that the probability of the codeword being selected is high; conversely, the selection probability value is small, it indicates that the probability of the codeword being selected is low;
[0076] The error probability value is large, indicating that the receiving end sends a sequence number corresponding to a codeword, and the sending end has a high probability of obtaining a sequence number corresponding to another codeword; conversely, the error probability value is small, indicating that the receiving end sends a code The serial number corresponding to the word, the sending end has a low probability of getting the serial number corresponding to another code word;
[0077] The small similarity value indicates that the similarity between the two codewords is high; on the contrary, the large similarity value indicates that the similarity between the two codewords is low.
[0078] The codebook selection device with anti-feedback error provided by the embodiment of the present invention compiles codebooks with various correspondences between codewords and serial numbers through the codebook generation module; the error acquisition module obtains the transmission error parameter value of each codebook, and can evaluate The ability of each codebook to resist feedback errors; the codebook optimization module then selects the codebook with the smallest transmission error parameter value as the new codebook shared by the signal sending end and the receiving end. In this way, the new codebook obtained will be the one with the strongest ability to resist feedback errors among the codebooks. Applying the new codebook at the transmitting end and the receiving end can make the beam used by the transmitting end match the current channel as much as possible, ensuring The transmission performance of the system.
[0079] Those skilled in the art can understand that when implementing the present invention, the codebook optimization module does not have to select the codebook with the smallest transmission error parameter value, and it can also select the codebook with the second or smaller transmission error parameter value to select the transmission error. The codebook with the smallest parameter value as the codebook shared by the signal transmitter and receiver is only an alternative and optimal solution. Therefore, the codebook optimization module can select a suitable codebook by transmitting the error parameter value according to the characteristics of the network system or the actual needs of the operator.
[0080] The above are only specific implementations of the embodiments of the present invention, but the scope of protection of the embodiments of the present invention is not limited thereto. Any person skilled in the art can easily think of it within the technical scope disclosed in the present invention. All changes or replacements shall be covered by the protection scope of the present invention. Therefore, the protection scope of the embodiments of the present invention should be subject to the protection scope of the claims.
