阅读说明：本技术 一种已知支路信息turbo码删除模式估计方法 (Known branch information turbo code deletion mode estimation method ) 是由 甘露 于雄雄 宫春涛 廖红舒 于 2019-09-27 设计创作，主要内容包括：本发明属于turbo码盲识别技术领域,具体涉及一种已知支路信息turbo码删除模式估计方法。本发明利用支路编码序列和信息位序列长度比值与删除比特个数与删除周期长度比值相等的关系,估计删除周期。然后再通过删除卷积码的识别方法得到生成矩阵,利用估计得到的生成矩阵重新生成支路序列,比对其正确性,从而确定支路的删除模式以及生成矩阵。本发明针对具有复杂删除模式的支路信息已知的turbo码进行识别,能够对具有多个1的复杂删除模式进行有效识别。很好的适应于实际的turbo码识别应用中。(The invention belongs to the technical field of turbo code blind identification, and particularly relates to a known branch information turbo code deletion mode estimation method. The invention estimates the deleting period by utilizing the relation that the ratio of the branch coding sequence to the length of the information bit sequence is equal to the ratio of the number of the deleting bits to the length of the deleting period. Then, a generating matrix is obtained by an identification method of deleting the convolutional codes, the branch sequence is regenerated by using the generating matrix obtained by estimation, and the correctness of the branch sequence is compared, so that the deleting mode of the branch and the generating matrix are determined. The invention identifies the turbo code with known branch information of the complex deleting mode, and can effectively identify the complex deleting mode with a plurality of 1. The method is well suitable for practical turbo code identification application.)

1. A method for estimating an erasure pattern of a known tributary information turbo code, comprising the steps of:

s1, initializing, wherein the information bit sequence is A ═ a₁a₂....a_NN is the length of information bit sequence, and the check output sequence of non-interlaced branch circuit is B ═ B₁b₂...b_MM is the length of the non-interleaved branch check output sequence, and the interleaved branch check output sequence is C ═ C₁c₂...c_LL is the length of the interleaved branch check output sequence; the code length is n, the information bit length is k, and the deletion period upper limit product factor is alpha;

s2, carrying out deletion mode identification on the non-interleaved branch check output sequence, wherein the identification threshold is theta:

s21, initializing the estimation deletion period T_PAnd the number N of 1 s in the deletion mode_P，

S22 deletion of period T_PAnd the number N of 1 s in the deletion mode_PConstruct a set of all possible deletion patterns P:

S23, using the information bit sequence as A ═ a₁a₂....a_NAnd the non-interleaved branch check output sequence is B ═ B₁b₂...b_MConstruct a code rate of T_P/(T_P+1), the output pattern is:

solving by utilizing a binary collision algorithm to obtain a check polynomial matrix of H (x);

s24, making the deletion convolutional code check matrix to be identified as

wherein

a set of possible deletion patterns is constructed,

s25, selecting one generation mode P from S in sequence, and constructing and deleting the convolutional code C_PThe generator polynomial matrix of (a) is:

wherein eta_P＝(η_P(1),η_P(2),...,η_P(i),...,η_P(n₀) Position vector, η) representing the deletion pattern P_P(i) Indicating that the ith 1 in P is positioned at the position of the P column according to the check relation G_P(x)H^T(x) When it is 0, a linear equation set G (α) is obtained₀,α₁,...,α_κ,λ₀,λ₁,...,λ_κ)^T0, where G is one ((n-1) × 2(κ +1)) matrix on F;

s26, solving the equation system obtained by S25 to obtain a non-zero basic solution system omega, and expressing the elements in omega as

s27, checking

s28, selecting all deleting modes

s29, selecting the ith element P in S_iEncoding the information bit sequence using the generator polynomial matrix G estimated in steps S23 to S28 to obtain an encoded output D ═ D₁d₂....d_NAccording to P_iDeleting coded output D to obtain sequence

Step S24 is proceeded to until

s3, carrying out deleting mode P and interleaving depth N on the interleaved branch checking output sequence_SAnd the interleaving relation pi_SIdentification:

s31, known interleaving depth N_SInitializing the estimated deletion period T_PAnd the number N of 1 s in the deletion mode_P，

S32, constructing all possible class generator polynomial matrix sets according to the dimension of the generator polynomial matrix G obtained in S2 because the two branch encoders are similar encoders:

m_G,n_Grepresenting the number of rows and columns of the generator matrix G, the total number of elements of the set being N_G；

S33 deletion of period T_PAnd the number N of 1 s in the deletion mode_PConstruct a set of all possible deletion patterns P:

S34, interleaving depth N_SConstructing an interleaving branch input data matrix X:

initializing i, i to 1;

s35, selecting the ith element P in S_iOutputting the interleaving according to the deleting mode:

zero padding is performed, that is, the interleaved output bit to be deleted is set to 0, and the interleaved output data after zero padding is:

constructing interleaved encoded output matrices

Initializing j, j to 1;

s36, selecting S_GThe j (th) element of (1)

using deletion pattern P_iBy performing erasure replacement on the coded output C ', i.e. in C' according to the erasure pattern P_iAll the parts to be deleted are replaced by 0 to obtain a coding output matrix

Initializing l and interleaving relation pi_S：l＝1，

S37、In that

Judging again

s4, outputting a check bit deleting mode P_iAnd generating a polynomial matrix G and a deletion period T_P；

S5, outputting erasure cycle T obtained by interleaving bit identification_PGenerating a polynomial matrix

And S6, outputting that the recognition result is not obtained.

Technical Field

The invention belongs to the technical field of turbo code blind identification, and particularly relates to a known branch information turbo code deletion mode estimation method.

Background

In the CCSDS protocol, parallel concatenated class (PCCC) Turbo code coding with erasure makes the parity bits and interleaving parity output, and the erasure pattern only exists in one 1 in one erasure period. The same turbo code for the dual input class also has a similar erasure pattern. But in practical applications complex deletion patterns with more than 1's may occur. The estimation of this type of deletion pattern is relatively complex. The code length and information bit position as well as the data sequence of each branch need to be known. The erasure pattern, the code generator matrix and the interleaving mode can be identified on the basis of the known methods.

Disclosure of Invention

The invention provides a method for identifying the complex deletion mode of the turbo code with known branch information, which enlarges the range of the turbo code for identifying the deletion mode and effectively improves the reliability of the blind identification of the turbo code.

The technical scheme of the invention is as follows: a method for identifying a known code length, an information bit position and a data sequence PCCC-turbo complex deletion mode of each branch. And estimating the deletion period by utilizing the relation that the ratio of the branch coding sequence to the length of the information bit sequence is equal to the ratio of the number of the deletion bits to the length of the deletion period. Then, a generating matrix is obtained by an identification method of deleting the convolutional codes, the branch sequence is regenerated by using the generating matrix obtained by estimation, and the correctness of the branch sequence is compared, so that the deleting mode of the branch and the generating matrix are determined; the invention mainly comprises the following steps:

s1, initializing, wherein the information bit sequence is A ═ a₁a₂....a_NN is the length of information bit sequence, and the check output sequence of non-interlaced branch circuit is B ═ B₁b₂...b_MM is the length of the non-interleaved branch check output sequence, and the interleaved branch check output sequence is C ═ C₁c₂...c_LAnd L is the interleaving branch check output sequence length. The code length is n, the information bit length is k, and the upper limit product factor of the deletion period is alpha.

S2, carrying out deletion mode identification on the non-interleaved branch check output sequence, wherein the identification threshold is theta:

s21, initializing the estimation deletion period T_PAnd the number N of 1 s in the deletion mode_P，

gcd (N, M) represents the greatest common divisor of N, M, M ≦ N, when there is a deletion in the branch code, M<N；

S22 deletion of period T_PAnd the number N of 1 s in the deletion mode_PConstruct a set of all possible deletion patterns P:

is a binary finite field T_PDimensional space, total number of collection elements

S23, using the information bit sequence as A ═ a₁a₂....a_NAnd the non-interleaved branch check output sequence is B ═ B₁b₂...b_MConstruct a code rate of T_P/(T_P+1), the output pattern is:

solving by utilizing a binary collision algorithm to obtain a check polynomial matrix of H (x);

s24, making the deletion convolutional code check matrix to be identified asn₀The number of neutron generating polynomials in H (x). The maximum polynomial degree of the check matrix isThe upper limit of the degree of the source generator polynomial is κ ═ n₀-1) (d +1) -1, setting 1/2 rate source code generator polynomial as

α_i，λ_iTo generate coefficients of a polynomial. Construct a code rate of (n)₀-1)/2(n₀-1) generating a polynomial matrix G' (x):

wherein

F (x) represents the entire set of polynomials.

i＝0,1,...,l-1,l＝n₀-1,m＝1,2

A set of possible deletion patterns is constructed,is a binary finite field 2n₀-a 2-dimensional space.

S25, selecting one generation mode P from S in sequence, and constructing and deleting the convolutional code C_PThe generator polynomial matrix of (a) is:

G_P(x)＝[G′(x)]_ηP

wherein eta_P＝(η_P(1),η_P(2),...,η_P(i),...,η_P(n₀) Position vector, η) representing the deletion pattern P_P(i) Indicating that the ith 1 in P is positioned at the position of the P column according to the check relation G_P(x)H^T(x) When it is 0, a linear equation set G (α) is obtained₀,α₁,...,α_κ,λ₀,λ₁,...,λ_κ)^T0, where G is one ((n-1) × 2(κ +1)) matrix on F;

s26, solving the equation system obtained by S25 to obtain a non-zero basic solution system omega, and expressing the elements in omega as

Wherein

Representing a binary finite field k-dimensional space,F^κ(x) Representing a set of k-th order polynomials. Memo

The same process is also performed to select the corresponding in Ω

Recording and storing the solution with the minimum order kappa and the order thereof;

s27, checking

If it is

All possible of

Calculated, proceed to step S28; otherwise, returning to the step S25 to continue calculation;

s28, selecting all deleting modes

Taking the solution with the minimum corresponding order as an estimated value, wherein the solution corresponds to the estimation of a erasure code source code generation polynomial matrix G, and initializing i, i to be 1;

s29, selecting the ith element P in S_iEncoding the information bit sequence using the generator polynomial matrix G estimated in steps S23 to S28 to obtain an encoded output D ═ D₁d₂....d_NAccording to P_iDeleting coded output D to obtain sequence

If it is notProceed to S4; if not, i is i +1, the procedure is repeated until

Establishing, updating the deletion period T_PAnd the number N of 1 s in the deletion mode_P：

Step S24 is proceeded to until

Or

If true, the routine proceeds to step S6;

s3, carrying out deleting mode P and interleaving depth N on the interleaved branch checking output sequence_SAnd the interleaving relation pi_SIdentification:

s31, known interleaving depth N_SInitializing the estimated deletion period T_PAnd the number N of 1 s in the deletion mode_P，

S32, constructing all possible class generator polynomial matrix sets according to the dimension of the generator polynomial matrix G obtained in S2 because the two branch encoders are similar encoders:

m_G,n_Grepresenting the number of rows and columns of the generator matrix G, the total number of elements of the set being N_G；

S33 deletion of period T_PAnd the number N of 1 s in the deletion mode_PConstruct a set of all possible deletion patterns P:

is a binary finite field T_PDimensional space, total number of collection elements

S34, interleaving depth N_SConstructing an interleaving branch input data matrix X:

initializing i, i to 1;

s35, selecting the ith element P in S_iOutputting the interleaving according to the deleting mode:

zero padding is performed, that is, the interleaved output bit to be deleted is set to 0, and the interleaved output data after zero padding is:

constructing interleaved encoded output matrices

Initializing j, j to 1;

s36, selecting S_GThe j (th) element of (1)

By using

Encoding X yields the encoded output as:

using deletion pattern P_iTo coded output CDeletion replacement, i.e. in C' in deletion mode P_iAll the parts to be deleted are replaced by 0 to obtain a coding output matrix

Initializing l and interleaving relation pi_S：l＝1，

In that

Seek to makeColumn vector ofIf present, then pi_S(μ) ═ l, l ═ l +1, and the procedure was repeated until l>N_SProceeding to step S5; if not, j is j +1, and j is judged>N_GIf not, go back to step S36; if so, i is i +1, pairJudging, if it is false, proceeding to step S35, if it is true, updating the deletion period T_PAnd the number N of 1 s in the deletion mode_P:

Judging again

Or

If yes, the process proceeds to step S33, if no, the process proceeds to step S6;

s4, outputting a check bit deleting mode P_iAnd generating a polynomial matrix G and a deletion period T_P；

S5, outputting erasure cycle T obtained by interleaving bit identification_PGenerating a polynomial matrix

Deletion pattern P_iAnd the interleaving relation pi_S；

And S6, outputting that the recognition result is not obtained.

The invention identifies the turbo code with known branch information of the complex deleting mode, and can effectively identify the complex deleting mode with a plurality of 1. The method is well suitable for practical turbo code identification application.

Drawings

FIG. 1 is a flow chart of a parity bit erasure pattern recognition method according to the present invention

FIG. 2 is a flow chart of the interleaved bit erasure pattern and the interleaving identification method of the present invention

FIG. 3 is a graph showing the check bit erasure pattern recognition accuracy varying with the error code in embodiment 1 of the present invention

FIG. 4 is a schematic diagram showing the relationship between the frame length and the bit error rate recognition threshold after the method of the present invention is adopted

Detailed Description

The invention is described in detail below with reference to the figures and examples

Fig. 1 is a flow chart of the method for identifying the erasure pattern of the parity bits according to the present invention, and as shown in the figure, the method for identifying and estimating the erasure pattern of the parity bits according to the present invention comprises the following steps:

s1 is initialized, and the information bit sequence is A ═ a₁a₂....a_NN is the length of information bit sequence, and the check output sequence of non-interlaced branch circuit is B ═ B₁b₂...b_MM is the length of the non-interleaved branch check output sequence, and the interleaved branch check output sequence is C ═ C₁c₂...c_LAnd L is the interleaving branch check output sequence length. The code length is n, the information bit length is k, and the upper limit product factor of the deletion period is alpha.

S2, carrying out deletion mode identification on the non-interleaved branch check output sequence, wherein the identification threshold is theta

S21 initializing the estimated deletion period T_PAnd the number N of 1 s in the deletion mode_P，Where N, M denotes the information bit sequence a ═ a₁a₂...a_NAnd the non-interleaved branch circuit check output sequence is B ═ B₁b₂...b_MLength of (d). gcd (N, M) represents the greatest common divisor of N, M, with M ≦ N. When there is a deletion in the branch encoding, M<N。

S22 deleting the period T_PAnd the number N of 1 s in the deletion mode_PConstruct a set of all possible deletion patterns P:

is a binary finite field T_PDimensional space, total number of collection elements

S23 uses the information bit sequence as a ═ a₁a₂....a_NAnd the non-interleaved branch check output sequence is B ═ B₁b₂...b_MConstruct a code rate of T_P/(T_P+1), the output pattern is:

and solving by using a binary collision algorithm to obtain a check polynomial matrix of H (x).

S29 selecting the ith element P in S_iEncoding the information bit sequence using the generator polynomial matrix G estimated in steps S23 to S28 to obtain an encoded output D ═ D₁d₂....d_NAccording to P_iDeleting coded output D to obtain sequence

If it is not

Proceed to S4. If not, i is i +1, the procedure is repeated until

If the number of the first-time-series terminal,

updating the deletion period T_PAnd the number N of 1 s in the deletion mode_P:

Proceed to S24 until

Or

If it is

Or

The no-identification result is output.

Fig. 2 is a flowchart of the method for deleting interleaved bits and identifying interleaved bits according to S31-S35 of the present invention, and as shown in the figure, the method for deleting interleaved bits and identifying interleaved bits includes the following steps:

s31 initializing the estimated deletion period T_PAnd the number N of 1 s in the deletion mode_P，

S32, because the two branch encoders are similar encoders, we construct all possible sets of class-like generator polynomial matrices according to the dimension of the generator polynomial matrix G obtained in S2:

m_G,n_Grepresenting the number of rows and columns of the generator matrix G, the total number of elements of the set being N_G；

S33 deleting the period T_PAnd the number N of 1 s in the deletion mode_PConstruct a set of all possible deletion patterns P:

is a binary finite field T_PDimensional space, total number of collection elementsInitializing i, i-1

S34 selecting the ith element P in S_iOutputting the interleaving according to the deleting mode:

zero padding is performed, that is, the interleaved output bit to be deleted is set to 0, and the interleaved output data after zero padding is:

from N_SConstructing interleaved encoded output matrices

Initializing j and interleaving relation: j is equal to 1, and j is equal to 1,

S35-S37 selecting S_GThe j (th) element of (1)

By using

Method pair by decoding contrast

And carrying out interleaving identification. If the identification is successful, the process proceeds to S5. If not, j equals j +1, for j>N_GAnd (4) judging, and repeating the step if the judgment result is false. If the judgment result is true, i is equal to i +1, and the judgment is made

If not, the process proceeds to S34, and if so, the deletion period T is updated_PAnd the number N of 1 s in the deletion mode_P:

Judging again

Or

If the judgment result is false, the process goes to S33, and if the judgment result is true, the process goes to S6;