KR101848431B1 - Apparatus and method for estimating intereaving period of signal - Google Patents

Abstract

A method for estimating the interleaving period of a signal according to an aspect of the present invention includes a step of obtaining an analysis target signal having a plurality of codes and being a part of an input signal interleaved in a predetermined cycle, a step of sequentially repeating a process of dividing the analysis target signal and generating a plurality of divided signals including L (L is a natural number) signs, a process of generating a determination matrix, which is a matrix comprising a plurality of selection signals selected from the divided signals as rows, and a process of calculating a difference between a value which is not larger than the number of rows and the number of columns and the value of the rank of the determination matrix, with regard to each of the predetermined plurality of different values of L, and a step of estimating one of the values of L as the interleaving period of the input signal based on the difference value calculated for each of the L values. It is possible to estimate the interleaving period of the signal with high accuracy even in the absence of information on the signal.

Description

[0001] APPARATUS AND METHOD FOR ESTIMATING INTEREAVING PERIOD OF SIGNAL [0002]

The present invention relates to an apparatus and a method for estimating an interleaving period of a signal having a plurality of rows.

Interleaving of a signal refers to changing the positions of all or a part of symbols included in a signal having a sequential form (i.e., the order of appearance in the signal). On the side to transmit a signal including predetermined information, error correction encoding and interleaving are successively performed on the signal before transmitting the signal through a communication channel. Through the interleaving, error can be prevented from being concentrated in a specific part of the signal before interleaving, and the effect of permutation encryption can be achieved.

Such interleaving is generally performed in a predetermined period. For example, suppose that the interleaving period of a signal is 16. Then, in the process of performing the interleaving, the signal is divided into a plurality of signals (hereinafter referred to as "divided signals") each having 16 codes per one, and the positional change of each code, Only within the signal. According to this, position exchange between two codes belonging to different divided signals does not occur.

In order to read the information contained in the signal transmitted through the communication channel, it is necessary to know not only the method of encrypting the signal but also the manner in which the signal is interleaved, and restores the interleaved signal into a signal before interleaving In order to do this, firstly, the interval of the interleaving must be known. In a situation where the receiver and the transmitter can share information about the transmission of signals smoothly, there is little problem in determining the interleaving period. However, in a situation where there is no information about the received signal, such as a situation in which the enemy signal received from the battlefield needs to be decoded, the decision of the interleaving cycle can not but be relied upon.

Patent Document: Korean Patent Laid-Open No. 10-2016-0034031 (published on Mar. 29, 2016)

An object of the present invention is to provide an apparatus and method for estimating an interleaving period of a signal received through a communication channel with high accuracy even in the absence of information on the signal.

It is to be understood, however, that the scope of the present invention is not limited to the above-mentioned objects, and may be embodied from the following description, which may be understood by those skilled in the art to which the present invention belongs. have.

According to an aspect of the present invention, there is provided a method for estimating an interleaving period, the method comprising: acquiring an analysis target signal having a sequence of a plurality of codes, the analysis target signal being a part of an input signal interleaved at predetermined intervals; Generating a plurality of divided signals including L (L is a natural number) code by dividing a plurality of divided signals into a plurality of divided signals; generating a discrimination matrix which is a matrix constituted by a plurality of selected signals selected from the divided signals; A step of calculating a difference between a value of a row of the determination matrix and a value of a rank not greater than the number of rows and a value of rank of the determination matrix is repeated for each of a predetermined plurality of different values of L, Estimating one of the values of L as an interleaving period of the input signal based on the difference value calculated for each of the values of L, It may include the step.

The estimating step may include estimating a value of L having a largest value of the difference among the values of L as an interleaving period of the input signal.

(D + 1) (where d is an integer equal to or greater than 0 and equal to or less than L) among the signs of the analysis target signal, when the number of codes included in the analysis target signal is M, And setting a division target signal composed of consecutive codes of T (T is the largest number of L's not larger than Md) starting from the 1 < th > code, and dividing the division target signal by T / And the like.

It is preferable that the step of repeating includes the step of generating a candidate decision matrix, which is a matrix constituted by a plurality of K divided signals (K is a natural number) selected from the divided signals, And determining a candidate decision matrix having the smallest value of the dimension among the L candidate decision matrices as the decision matrix.

In addition, the step of generating the determination matrix may include: selecting randomly the L divided signals among the divided signals, and generating the square matrix of L x L constituting each of the L divided signals as N (N A step of extracting a square matrix having a difference between a value of dimension and a value of L among the N square matrices equal to or greater than a predetermined threshold difference and a number of times appearing in each row of the extracted square matrix (K is a natural number) divided signals among the divided signals as the selection signal in order of increasing number of the divided signals.

Also, the value of K may be determined to be larger than a largest value among the values of L by a predetermined positive constant.

An apparatus for estimating an interleaving period according to an exemplary embodiment of the present invention includes an input unit that acquires an analysis target signal having a plurality of codes and a part of an input signal interleaved in a predetermined cycle, Generating a plurality of divided signals including L (L is a natural number) code by dividing a plurality of divided signals into a plurality of divided signals; generating a discrimination matrix which is a matrix constituted by a plurality of selected signals selected from the divided signals; A step of calculating a difference between a value of a row of the determination matrix and a value of a rank not greater than the number of rows and a value of rank of the determination matrix is repeated for each of a predetermined plurality of different values of L, Based on the value of the difference calculated for each of the values of L and one of the values of L as the interleaving period of the input signal Determining estimates may include a.

The estimator may estimate a value of L having the largest difference among the L values as the interleaving period of the input signal.

In addition, the operation unit may be configured such that when the number of codes included in the analysis target signal is M, T ((d) is a code sequence starting from a sign of d + 1 (d is an integer of 0 or more and less than L) T is the largest number of L's not larger than Md) consecutive codes, and divides the division target signal by T / L to generate the division signal.

Also, the operation unit may be configured to perform, for each of all the constants that can be the value of d, to generate a candidate decision matrix, which is a matrix constituted by rows of K (K is a natural number) And the candidate determination matrix having the smallest value of the dimension among the L candidate determination matrices can be determined as the determination matrix.

It is also preferable that the calculation unit randomly selects L divided signals among the divided signals and generates L x L square matrixes each constituting a row of the L divided signals by repeating N (N is a natural number) And extracts a square matrix having a difference between a value of dimension and a value of L out of the N square matrix by a predetermined threshold difference or more, And K (K is a natural number) divided signals among the signals can be selected as the selection signal.

Also, the value of K may be determined to be larger than a largest value among the values of L by a predetermined positive constant.

According to an embodiment of the present invention, the linearity of an unknown signal received through a communication channel can be used to estimate an interleaving period for the signal with high accuracy. Further, according to the embodiment of the present invention, since a portion of an unknown signal having a low error rate can be selected and used for estimation of the interleaving period, the accuracy of the estimation can be further increased.

1 is a block diagram of an apparatus for estimating an interleaving period according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating each step of the interleaving cycle estimation method according to an embodiment of the present invention. Referring to FIG.
3 is a diagram for explaining channel encoding, interleaving of a signal, and error occurrence in a channel.
4 to 7 are diagrams for explaining the results of a simulation using the interleaving cycle estimation method according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions in the embodiments of the present invention, which may vary depending on the intention of the user, the intention or the custom of the operator. Therefore, the definition should be based on the contents throughout this specification.

1 is a block diagram of an apparatus for estimating an interleaving period according to an embodiment of the present invention. The interleaving period estimation apparatus 100 of FIG. 1 may include an input unit 110, an operation unit 120, an estimation unit 130, and an output unit 140. However, the interleaving period estimation apparatus 100 of FIG. 1 is only an embodiment of the present invention, and therefore the concept of the present invention is not limited to FIG.

The input unit 110 may receive a signal transmitted through a communication channel, which is an object of interleaving period estimation. The input signal input through the input unit 110 may have a form of a series of a plurality of codes. The input signal is interleaved in a predetermined cycle, and the input unit 110 may obtain a part of the input signal as an analysis target signal for estimating the interleaving period. In order to perform such a function, the input unit 110 may include a receiving device such as an antenna for receiving a signal from a communication channel.

The calculation unit 120 can extract data for estimating the interleaving period of the input signal input through the input unit 110 from the analysis target signal. More specifically, the operation unit 120 may divide the analysis target signal at a predetermined natural number. By the division, the analysis target signal is divided into a plurality of signals (hereinafter, referred to as "divided signals") each including the sign of the arbitrary natural number. The calculation unit 120 obtains a determination matrix, which is a matrix in which rows are formed by a plurality of selection signals selected from the division signals, and determines a maximum rank that the determination matrix can have, The difference between the actual dimensions of the matrix can be calculated.

The operation unit 120 may perform the process of obtaining the difference value as described above while changing the dividing period of the analysis target signal. The difference value calculated for each division period by the operation unit 120 can be used by the estimation unit 130 to estimate the interleaving period of the input signal. The arithmetic unit 120 may be implemented by an arithmetic unit including a microprocessor, which is the same in the estimator 130 described below.

The estimator 130 may estimate one of the values of the dividing periods as the interleaving period of the input signal based on the difference value calculated for each dividing period by the calculating unit 120. [ More specifically, the estimator 130 estimates, as the interleaving cycle of the input signal, the value of the dividing period having the largest difference between the maximum dimension that the determination matrix can have and the actual dimension of the determination matrix, from among the values of each division period .

The operation of the calculating unit 120 and the estimating unit 130 for estimating the interleaving period of the input signal may be performed by the linearity of the input signal, that is, a part of the sign of the input signal may be a linear combination And a more detailed description thereof will be described in detail below with reference to FIG. 2 and other drawings thereafter.

The output unit 140 may output the value of the interleaving period of the input signal estimated by the estimating unit 130 to the outside of the interleaving period estimating apparatus 100. [ The output may be an output of a physical form that can be perceived visually or audibly, or it may be an electronic form of output that may be transmitted over a wired or wireless communication network. Accordingly, the output unit 140 may include a visual output device, such as a display, or an auditory output device such as a speaker, and in some cases, may output data to the outside of the interleaving period estimation device 100 A data bus for transmitting data, a wired / wireless communication module, and the like.

FIG. 2 is a diagram illustrating each step of the interleaving cycle estimation method according to an embodiment of the present invention. Referring to FIG. The interleaving period estimation method of FIG. 2 may be performed by the interleaving period estimation apparatus 100 described with reference to FIG. However, since the method shown in FIG. 2 is only an embodiment of the present invention, the concept of the present invention is not limited to FIG. 2, and each step of the method shown in FIG. And may be performed in a different order of the bar and the order.

First, the input unit 110 can acquire an input signal to be subjected to the interleaving cycle estimation (S101). The transmitting side of the input signal sequentially performs an encryption process, a channel coding process, and an interleaving process on a signal including predetermined information, and then transmits the generated input signal to the communication channel after completing the processes .

Of the above processes, channel coding is a process for preparing for a case where an error occurs in a part of a signal transmitted through a communication channel. The channel encoded signal further includes redundancy in comparison to the original signal, which may be an additional code that was not present in the original signal. The additional code may be a code having a value corresponding to a linear combination of codes existing in the original signal. Accordingly, even if an error occurs in a code existing in the original signal, an additional code is used to restore the error- It is possible.

3 is a diagram for explaining channel encoding, interleaving of a signal, and error occurrence in a channel. The first signal 210 in the form of a sequence generated and encrypted on the receiving side may be a form in which a plurality of messages (or information codes) are combined in a row as shown in FIG. In the four messages 211, 212, 213, and 214, which are part of the message, one message includes four symbols. When channel coding is performed on the first signal 210, a second signal 220 in which redundant data is added to each message is generated. Accordingly, the four codewords 221, 222, 223, and 223 generated from the four messages 211, 212, 213, and 214 of the first signal 210 among the codewords of the second signal 220, 224 each include two additional codes in addition to the original four codes.

In one code word, the four preceding codes are data codes that also existed in the first signal 210, and there is no mutual dependency therebetween. However, the latter two codes are redundant codes generated by the linear combination of some of the preceding four codes, and their values are determined according to the values of the four preceding codes. The fifth code (x ₁ + x ₂ ) is the sum of the first code (x ₁ ) and the second code (x ₂ ), and the sixth code (x ₃ + x ₄ ) is defined as the sum of the third code (x ₃ ) and the fourth code (x ₄ ), respectively. And the values of the fifth code and the sixth code are determined by the same rule in the remaining three code words 222, 223, and 224.

The (n, k) code word c, which is a codeword whose length (including the length of the included code) is n and the number of codes for which the value of the included code is independently determined is k, is expressed by the following Equation 1 Can be expressed as a product of a matrix m having a size of 1 xk and a matrix G having a size of kxn.

Equation (1) may also be used when the second signal 220 is generated in the first signal 210 of FIG. For example, if m is a specific message of the first signal 210 and c is a codeword of the second signal 220 corresponding to the specific message, m will be a 1 x 4 matrix and c 1 x 6 matrix , And G, which is a 4 x 6 matrix, can be expressed as in Equation (2).

When interleaving is performed on the second signal 220, a third signal 230 may be generated. Typically, the period of the interleaving is determined by a multiple of the length of the codeword, where the period of interleaving P is assumed to be twelve times the length 6 of each codeword in the second signal 220. Then, the position of each code changes according to a certain rule in one interleaving cycle.

Here, the first codeword 221 forming one interleaving period in the second signal 220 and the twelve codewords included in the second codeword 222 are rearranged. In the second signal _{(220) x 1, x 2} , x 3, x 4, x 1 + x 2, x 3 + x 4, y 1, y 2, y 3, y 4, y 1 + y 2, y ₃ + y 12 of marks that have been listed in the order of _4, the x _1, x ₁ + x _2, in a third signal (221) y _3, x _2, x ₃ + x _4, y _4, x _3, y ₁ , y ₁ + y ₂ , x ₄ , y ₂ , and y ₃ + y ₄ . The twelve codes of the third code word 223 and the fourth code word 224 forming the next interleaving cycle are also generated by the same rules as in the case of the first code word 221 and the second code word 222 3 < / RTI >

The third signal 230 may be transmitted from the transmitting side to the receiving side via the communication channel. In this case, the third signal 230 may have some errors in the code while passing through the non-ideal communication channel. However, the redundant code added in the channel coding process may overlap the information of the data code existing from the first signal 210 Therefore, the problem caused by such an error can be solved to some extent.

Also, even if errors occur consecutively to several consecutive symbols in the third signal 230, such errors can be distributed to a plurality of code words without being concentrated in one code word. This distribution of errors is an effect of interleaving. For example, assume that an error has occurred in four consecutive codes x ₃ , y ₁ , y ₁ + y ₂ , and x ₄ in the third signal 230. Since the positions of the four codes correspond to the positions of y ₁ , y ₂ , y ₃ , and y ₄ in the second signal 220, if the interleaving is not performed, Codeword 222. < / RTI > However, by virtue of the interleaving, the errors actually occurring in the third signal 230 are the two codes (x ₃ , x ₄ ) and the second code word 222 that belonged to the first code word 221 of the second signal 220, (Y ₁ , y ₁ + y ₂ ) belonging to the same group. That is, it can be said that the burst error is converted into a random error due to the interleaving process.

Return to FIG. 2 again. The input unit 110 acquiring the input signal sets all or a part of the acquired input signal as an analysis target signal, and transmits the signal to the calculation unit 120 (S102). The calculation unit 120 receiving the analysis target signal can set a predetermined number of different natural numbers as interleaving cycle candidates (S103), and perform the following steps S105 to S110 for each of the interleaving cycle candidates.

Before describing the detailed operation of the operation unit 120, the principle of the interleaving cycle estimation method according to an embodiment of the present invention will be described. First, assume that for any arbitrary natural number L, there is a square matrix A with a size of L x L. If L vectors constituting each L rows (or L columns) of A are independent of each other, that is, if none of the L vectors can be represented by the linear combination of the other L-1 vectors, A Is composed of a total of L independent vectors. Therefore, in this case, the rank of A becomes L, the maximum value of the dimension that A can have. However, if there exists a vector that can be represented as a linear combination of other vectors among L vectors, the dimension of A is smaller than L. In general terms, the dimension of A corresponds to the number of independent basis vectors among the L vectors included in A.

Here, each respective total L ² of the elements of A is a one-bit (bit) to 0 and and which can have a value of 1, the probability that the value of any element is the probability and 1 become 0, 0.5 Assume the same. If the probability that the dimension of A is Ls is P (Ls) and the value of s is divergent to infinity (that is, the difference between the maximum value of the dimension A can have and the value of the dimension of the actual A) The relationship between the values of P (Ls) is shown in Table 1 below.

s P (L-s) 0 0.288788 One 0.577576 2 0.128350 3 0.005238 4 4.65669 x 10 ^-5 5 9.69136 x 10 ^-8

Table 1 shows the probability of diverging L to infinity. However, even if the value of L is slightly increased, the value of P (L-s) tends to approach the distribution of Table 1 quickly. Therefore, in the present invention, it is assumed that the value of L is determined within a range in which the distribution of Table 1 can be applied as it is.

As can be seen in Table 1, when each element of A is randomly selected from 0 and 1, the probability that s becomes 3 or more is extremely low at 0.5% level. Even if each element of A is a code having a larger number than one bit, the probability that s becomes 3 or more is very low.

Hereinafter, the description of Table 1 will be applied to the interleaving cycle estimation method according to an embodiment of the present invention. An analysis object signal which is all or a part of an input signal is divided into divided signals each having a length of L (that is, including L codes), and then L divided signals among them are selected to form a row, Suppose that the process of generating a square matrix of x L is repeated a number of times. At this time, if the difference between the dimension of the generated square matrix and the value of L (the value of s in Table 1) is more than a certain level (for example, s? 3) It means that there are many divided signals that can be represented by linear combination of other divided signals.

When the input signal is a channel-encoded and interleaved signal as described with reference to FIG. 3, the value of L and the interleaving period of the input signal coincide with each other, and when one divided signal is a code The difference between the value of the dimension of the generated square matrix and the value of L will always be more than a predetermined constant. Of course, even if the value of L and the interleaving period of the input signal do not coincide with each other, a square matrix having a large difference value may be generated due to the error. However, the probability of the square matrix is extremely low . Accordingly, it is possible to estimate the value of L when the frequency of generation of the square matrix having the large difference value is high, as the interleaving period of the input signal.

However, since the actual channel environment in which the input signal is transmitted is not ideal, an error may occur in the transmission process in some of the signs of the input signal. This error affects the linear dependence of the input signal and consequently degrades the accuracy of the interleaving period estimation using the dimension of the matrix as described above. According to an embodiment of the present invention, a process of extracting a divided signal having a small number of errors among the divided signals having a length of L is performed for different L values (i.e., interleaving cycle candidate values) .

Return to FIG. 2 again. Suppose that the calculation unit 120 sets n total natural numbers of L ₁ , L ₂ , L ₃ , ..., L _n as interleaving cycle candidates through step S103. The operation unit 120 includes a first first interleaving period candidate for L ₁ (S104), the analyte signal to split the signal is generated has a length of as much as L ₁ can be divided from the very beginning (S105). At this time, when the length M of the analysis target signal is not a multiple of L ₁ , some codes at the end of the analysis target signal can be discarded without forming a split signal, and the number of discarded codes is M ₁ It will be equal to the value of the remainder divided.

Next, the operation unit 120 randomly selects L ₁ divided signals among the divided signals, and determines that each of the L ₁ divided signals generates a square matrix of L ₁ x L ₁ constituting a row, and N ( N is a natural number) (S106). Here, the value of N may be set to a sufficiently large value of about 1000. The calculator 120 calculates a square matrix having a difference s between the value of the dimension and the value of L ₁ of the N square matrices generated by the N repetition of the N repetitions by a predetermined threshold difference (for example, 3) A square matrix having a relatively lower dimension than the square matrix can be extracted (S107).

According to the above description, the divided signal constituting the extracted square matrix may be regarded as a divided signal having a relatively small error. On the basis of this, the calculation unit 120 selects K divided signals (K is a natural number) in the order of the number of appearing in each row of the extracted square matrix among the divided signals (S108) A candidate determination matrix, which is a matrix of K x L ₁ , in which rows are constituted by the selection signal, can be generated (S109). The larger the difference between this way the dimension of the generated candidate decision metric value and the candidate decision matrix, the maximum value that can have a value of D (that is, not larger side of the values of K and the value of L _1), L ₁ Is likely to be the interleaving period of the input signal.

However, even if the value of L ₁ actually has the same value as the interleaving period of the input signal, if one divided signal is not composed of only the codes belonging to the same interleaving period in the analysis target signal, the linear dependency between the divided signals is It may not be high. Assuming that the analysis target signal is set such that the input unit 110 receives the third signal 230 of FIG. 3 as an input signal and the _first sign of the analysis target signal is x ₁ + x ₂ instead of x ₁ lets do it.

Even if the length of the divided signal is equal to 12, which is the interleaving period of the third signal 230, the first divided signal is extracted from x ₁ to y ₃ + y ₄ And x ₁ + x ₂ to z ₁ , as a result of which the one divided signal does not consist of only the codes belonging to the same interleaving period in the analysis target signal. This phenomenon occurs because the input unit 110 can not know not only the interleaving period of the input signal but also the starting position of one interleaving period, which causes the linear dependency between the divided signals to deteriorate.

In order to solve such a problem, the process of deriving the candidate decision matrix from the divided signals through steps S105 to S109 for one interleaving cycle candidate can be performed several times while changing the division position.

More specifically, in the interleaving cycle candidate L ₁ , T (T is larger than Md) starting from the sign of d + 1 (d is an integer of 0 or more and less than L ₁ ) code of the analysis target signal having the length of M that is the largest of the multiple of L ₁₎ set the partition object signal consisting of a series of codes, and the divided target signal T / L ₁ equal parts to produce divided signals one the T / L ₁ has a length of L ₁ , And deriving a candidate decision matrix therefrom can be performed for each of all the integers that can be the value of d (i.e., each integer less than or equal to 0 and less than L ₁ ). L ₁ candidate decision matrices can be generated by this process, and the calculation unit 120 can select one of the candidate decision matrices (S110).

The selection of the decision matrix is performed by selecting among the L ₁ candidate decision matrices a candidate decision matrix having the largest difference between the values of the row number and the smallest number (that is, the maximum value of the dimension that can be included) . If the number of rows of each of the candidate decision matrices is equal to K, the candidate decision matrix having the lowest dimension among the L ₁ candidate decision matrices may be simply selected as the decision matrix.

It is noted that the above-described steps S105 to S110 may be performed for all the interleaving cycle candidates, respectively. Accordingly, the operation unit 120 may perform steps S105 to S110, which are performed on the assumption that the interleaving cycle candidate is L ₁ , for the other interleaving cycle candidates L ₂ , L ₃ , ..., L _n , A total of n decision matrices can be calculated for each cycle candidate.

When the calculation of the n judgment matrices is completed (S111 and S112), the estimator 130 determines whether the number of rows and the number of columns among the calculated judgment matrices, which is not the larger one (that is, (S113), and the interleaving cycle candidate corresponding to the selected determination matrix may be estimated as the interleaving cycle of the input signal (S114). That is, the estimator 130 estimates the interleaving cycle candidate having the largest linear dependency between the respective rows of the determination matrix as the interleaving period of the input signal.

On the other hand, the value of K, which is the number of rows of the judgment matrix (that is, the number of selection signals), can be differentiated according to the value of the interleaving cycle candidate. The reason for adjusting the value of K according to the value of the interleaving cycle candidates is that there is a correlation between the value of K and the probability of false alarm, which is a probability that the interleaving cycle estimation is wrong.

(L + q) x L (i.e., a matrix in which the number of rows is L + q and the number of columns is L) when the elements are randomly determined in a natural number L and an integer q equal to or larger than 0 The probability P (L, q) that has no maximum dimension is expressed by the following equation (3). In the following equation (3), the value of the probability P (L, q) largely depends on the value of q, since the (1-2- ^L ) portion of the equation (3) converges rapidly to 1 even if L is slightly increased. The value of P (L, q) becomes small.

The fact that the value of P (L, q) is large means that there is a high possibility that linear dependency happens accidentally between vectors constituting each row of the matrix having the size of (L + q) x L. Accidental occurrence of linear dependency is a factor for increasing the probability of false alarm even in the interleaving cycle estimation method according to an embodiment of the present invention.

Therefore, in the interleaving cycle estimation method according to the embodiment of the present invention, the value of K, which is the number of rows of the determination matrix calculated for each interleaving cycle candidate value, is set to a value larger than a certain level or more than a corresponding interleaving cycle candidate value . For example, the value of K may be set to a value larger than a corresponding interleaving cycle candidate value by a predetermined positive constant q.

As a specific example, assume that the three interleaving cycle candidate values L ₁ , L ₂ , and L ₃ are 7, 8, and 9, respectively. Then, the values of K ₁ , K ₂ , and K ₃ , which are the numbers of rows of the determination matrix corresponding to the _three interleaving cycle candidates, are obtained by adding 20, which is a predetermined positive constant, to the corresponding interleaving cycle candidate values 27 and 28 , And 29, respectively. In this case, the predetermined positive constant 20 corresponds to q in Equation (3), and when q is 20, the value of P (L, q) has a value substantially close to 0 regardless of the value of L will be. As described above, when the value of P (L, q) is small, it means that the probability of false alarm is low. In the above description, the value of K varies according to the value of the interleaving cycle candidate. However, the value of K may be fixed to a value larger by a predetermined positive constant than the largest value of the interleaving cycle candidate values.

In other words, the interleaving period estimation method according to the embodiment of the present invention adjusts the value of K, which is the number of rows of the decision matrix, to be sufficiently larger than the value of L, which is the interleaving cycle candidate value, Can be obtained.

4 to 7 are diagrams for explaining the results of a simulation using the interleaving cycle estimation method according to an embodiment of the present invention. 4, when simulation of the interleaving cycle estimation method according to an embodiment of the present invention is performed on the assumption that a (7, 4) binary Hamming code having an actual interleaving period S of 14 is an input signal, And the error rate of the selection signal with respect to the interleaving cycle candidate value. The value of L is set to a natural number between 7 and 15, the length of the signal to be analyzed is 50000, the number N of generating L x L square matrix N is 1000, and the number K of selection signals is 38.

In FIG. 4, the horizontal axis represents the bit error rate (BER) of the input signal passed through the channel, and the vertical axis represents the gain value related to the error rate of the 38 selection signals with respect to the value of each L. The value of the gain can be calculated by the following equation (4).

In Equation (4), the numerator represents the bit error rate of the input signal, and the denominator represents the bit error rate of the selection signals for the value of L, respectively. According to this, the value of the gain becomes larger as the error rate of the selection signals becomes lower.

4, when the value L of the interleaving cycle candidate is equal to 14, which is the actual interleaving period S of the input signal, the gain value is large. That is, FIG. 4 shows that split signals having fewer errors among the divided signals can be effectively selected when the value of L coincides with the value of S.

5 shows simulation results when only the actual interleaving period of the input signal is changed to 21 under the condition of FIG. 4. In the simulation of FIG. 5, when the value of the interleaving cycle candidate coincides with the actual interleaving period, Lt; / RTI > are effectively selected. However, in the case of L = 21 in FIG. 5, it can be seen that the gain value is generally decreased as compared with the case of L = 14 in FIG. 4. In order to increase the gain value, That is, when extracting a square matrix having a low dimension in the above-described step S107, a method of lowering the upper limit of the dimension of the square matrix to be extracted may be used.

FIGS. 6 and 7 are diagrams illustrating a result of a comparison simulation between a known interleaving cycle estimation method and an interleaving cycle estimation method according to an embodiment of the present invention. In FIGS. 6 and 7, the simulation conditions are as shown in Table 2 below. However, there is a difference that the length of the signal to be analyzed is 5000 for FIG. 6 and 50000 for FIG.

Type of input signal (7,4) Binary Hamming Code Of the input signal Interleaving  Period (S) 14, 21, 28 Interleaving  The cycle candidate value (L) Natural number less than or equal to 7 and less than or equal to S + 1 The number of selection signals (K) L + 24 random Square  Matrix generation repetition number (N) 1000 The length of the signal to be analyzed 5000 or 50000

6 and 7, the horizontal axis represents the bit error rate of the input signal, and the vertical axis represents the detection probability, which is a probability of correctly estimating the interleaving period of the input signal. The dotted line represents the detection probability of the conventional method, And the detection probability of the method according to Eq. Referring to FIGS. 6 and 7, it can be seen that the method according to an embodiment of the present invention exhibits a generally high detection probability in comparison with the conventional method under the condition of low bit error rate (less than 0.4%).

When the bit error rate is increased, the method according to an embodiment of the present invention shows a lower detection probability than the conventional method. However, the method according to an embodiment of the present invention shows higher performance than the prior art in terms of false alarm probability . 6, the method according to one embodiment of the present invention exhibits a false alarm probability of 0.007% and the prior art method 0.07%, respectively. In the simulation condition of FIG. 7, the method according to one embodiment of the present invention is 0.019 %, And the conventional method shows a false alarm probability of 1.13%, respectively.

In general, the detection probability and the false alarm probability are complementary, and if the false alarm probability is lowered, the detection probability may be lowered. However, in the case of the method according to an embodiment of the present invention, the detection probability is slightly reduced compared to the prior art under a high bit error rate condition, and a significant improvement is obtained in the false alarm probability. Accordingly, it can be said that the method according to an embodiment of the present invention exhibits a comprehensive improved performance as compared with the prior art.

As described above, according to the embodiment of the present invention, the interleaving period of the input signal can be estimated with high accuracy by using the linearity between codewords constituting the input signal, and a portion with low error rate of the input signal can be selected, The accuracy of the estimation can be further increased.

Combinations of each step of the flowchart and each block of the block diagrams appended to the present invention may be performed by computer program instructions. These computer program instructions may be loaded into a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus so that the instructions, which may be executed by a processor of a computer or other programmable data processing apparatus, And means for performing the functions described in each step are created. These computer program instructions may also be stored in a computer usable or computer readable memory capable of directing a computer or other programmable data processing apparatus to implement the functionality in a particular manner so that the computer usable or computer readable memory It is also possible for the instructions stored in the block diagram to produce a manufacturing item containing instruction means for performing the functions described in each block or flowchart of the block diagram. Computer program instructions may also be stored on a computer or other programmable data processing equipment so that a series of operating steps may be performed on a computer or other programmable data processing equipment to create a computer- It is also possible that the instructions that perform the processing equipment provide the steps for executing the functions described in each block of the block diagram and at each step of the flowchart.

Also, each block or each step may represent a module, segment, or portion of code that includes one or more executable instructions for executing the specified logical function (s). It should also be noted that in some alternative embodiments, the functions mentioned in the blocks or steps may occur out of order. For example, two blocks or steps shown in succession may in fact be performed substantially concurrently, or the blocks or steps may sometimes be performed in reverse order according to the corresponding function.

The above description is merely illustrative of the technical idea of the present invention, and various modifications and changes may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as falling within the scope of the present invention.

100: Interleaving period estimating device
110: input unit
120:
130:
140:

Claims (14)

Obtaining an analysis target signal which is a part of an input signal which has a plurality of codes and is interleaved in a predetermined cycle;
Generating a plurality of divided signals including L (L is a natural number) codes by dividing the signal to be analyzed; and generating a discrimination matrix, which is a matrix constituted by a plurality of selected signals selected from the divided signals Sequentially calculating a difference between a value of a row of the determination matrix and a value of a rank that is not greater than a row number of the determination matrix and a rank of the determination matrix, Repeating for each; And
Estimating one of the values of L as an interleaving period of the input signal based on the value of the difference calculated for each of the values of L
Interleaving period estimation method. The method according to claim 1,
Wherein the estimating includes estimating a value of L having a largest value of the difference among the values of L as an interleaving cycle of the input signal
Interleaving period estimation method. The method of claim 1, wherein the generating of the plurality of divided signals comprises:
(Where d is an integer equal to or greater than 0 and less than L) code among the codes of the analysis target signal, where T is the number of codes included in the analysis target signal, A maximum number of multiple of L) consecutive codes; And
And dividing the division target signal by T / L to generate the division signal
Interleaving period estimation method. 4. The method of claim 3,
Performing, for each of all the integers which can be the value of d, generating a candidate decision matrix, which is a matrix constituted by rows of K (K is a natural number) divided signals selected from the divided signals; And
Determining a candidate determination matrix having the smallest value of the dimension among the L candidate determination matrixes as the determination matrix
Interleaving period estimation method. 2. The method of claim 1, wherein the generating the decision matrix comprises:
Repeating N (N is a natural number) times of selecting L divided signals among the divided signals at random and generating L x L square matrices each constituting a row of the L divided signals;
Extracting a square matrix having a difference between a value of dimension and a value of L among the N square matrices equal to or greater than a predetermined threshold difference; And
Selecting K divided signals (K is a natural number) of the divided signals as the selection signal in the order of the number of times appearing in each row of the extracted square matrix;
Interleaving period estimation method. 6. The method of claim 5,
The value of K is determined to be larger than a largest value among the values of L by a predetermined positive constant
Interleaving period estimation method. An input unit for acquiring an analysis target signal having a plurality of codes and being a part of an input signal interleaved in a predetermined cycle;
Generating a plurality of divided signals including L (L is a natural number) codes by dividing the signal to be analyzed; and generating a discrimination matrix, which is a matrix constituted by a plurality of selected signals selected from the divided signals Sequentially calculating a difference between a value of a row of the determination matrix and a value of a rank that is not greater than a row number of the determination matrix and a rank of the determination matrix, An arithmetic operation unit for repeating the operation for each; And
And an estimator for estimating one of the values of L as an interleaving period of the input signal based on the value of the difference calculated for each of the values of L
/ RTI > 8. The method of claim 7,
Wherein the estimator estimates a value of L having a largest value of the difference among the values of L as an interleaving period of the input signal
/ RTI > 8. The method of claim 7,
(Where d is an integer equal to or greater than 0 and equal to or less than L) code among the codes of the analysis target signal, when the number of codes included in the analysis target signal is M, Md) of the number of consecutive codes), and generates the division signal by dividing the division target signal by T / L
/ RTI > 10. The method of claim 9,
Wherein the operation unit performs, for each of all the integers that can be the value of d, generating a candidate determination matrix, which is a matrix constituted by rows of K (K is a natural number) divided signals selected from the divided signals, Among the L candidate decision matrices, a candidate determination matrix having the smallest dimension value is determined as the determination matrix
/ RTI > 8. The method of claim 7,
The operation unit repeatedly repeats N (N is a natural number) times to select L divided signals of the divided signals at random and generate L x L square matrixes each constituting a row of the L divided signals, The method includes extracting a square matrix having a difference between a value of dimension and a value of L out of N square matrices by a predetermined threshold difference or more and arranging the squares in the order of the number of times appearing in each row of the extracted square matrix K (K is a natural number) divided signals as the selection signal
/ RTI > 12. The method of claim 11,
The value of K is determined to be larger than a largest value among the values of L by a predetermined positive constant
/ RTI > A program stored in a computer-readable medium for performing the respective steps according to the method of any one of claims 1 to 6. 7. A computer-readable medium having stored thereon instructions for performing the respective steps according to the method of any one of claims 1 to 6.

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