JP2018042035A - Encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable communication that is high in error correction capability and higher in transmission efficiency.SOLUTION: An encoder includes: a data acquisition unit for acquiring transmission object data corresponding to a code alphabet number associated with part of elements of a finite field having an element number of an integer power of a prime number; an encoding unit having recursive structure for executing encoding by convolution calculation using the elements of the finite field as a coefficient. Both of the code alphabet number of output of the encoding unit and the number of states of each memory in the encoding unit are the number of all the elements of the finite field.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an encoding device.

There is a convolutional code as one of error correction codes, and several techniques have been proposed in connection with this convolutional code.
For example, in Non-Patent Document 1, an encoding device that performs a recursive convolutional lattice code (RC) for a code alphabet having a lattice structure is arranged in parallel to obtain a turbo signal code. A technique for performing encoding called (Turbo Signal Code (s)) has been proposed.

  If the technique described in Non-Patent Document 1 is used, communication can be performed relatively easily using quadrature amplitude modulation. Moreover, if the technique described in Non-Patent Document 1 is used, iterative decoding similar to turbo decoding (Turbo Decode (s)) can be performed on the decoding side, and thereby decoding can be performed with relatively high accuracy. . As described above, according to the technique described in Non-Patent Document 1, communication can be performed using quadrature amplitude modulation, and a relatively high error correction capability can be obtained. Road capacity). On the other hand, in the technique described in Non-Patent Document 1, encoding operations are defined on a finite ring. However, in order to obtain higher error correction capability, a finite number in which four arithmetic operations are defined from the property of the set. Calculation on the body is preferable.

Patrick Mitran, and Hideki Ochiai, “Parallel Concatenated Convolutional Lattice Codes With Constrained States”, IEEE Transactions On Communications, April 2015, Vol. 63, No. 4, p. 1081-1090

From the viewpoint of improving the amount of communication, it is desirable that the error correction capability is high and the transmission efficiency is good.
The present invention provides an encoding device capable of communication with high error correction capability and higher transmission efficiency.

  According to the first aspect of the present invention, the encoding device includes a data acquisition unit that acquires transmission target data of a code alphabet number that is associated with a part of a finite field element number of prime integer powers; An encoding unit having a recursive structure and performing encoding by a convolution operation using a coefficient of the element of the finite field, the number of code alphabets output from the encoding unit, and the encoding unit The number of states of each memory is the total number of elements of the finite field.

  The first encoding unit that performs the encoding on the transmission target data acquired by the data acquisition unit, an interleaver that interleaves the transmission target data acquired by the data acquisition unit, and the interleaver interleaved You may make it provide the said 2nd encoding part which performs the said encoding with respect to the said transmission object data.

  A transmission unit may be provided that performs transmission with a codeword of a code alphabet number obtained by multiplying the number of code alphabets output from the first encoding unit by the number of code alphabets output from the second encoding unit. Good.

  According to the present invention, communication with high error correction capability and higher transmission efficiency is possible.

It is a schematic block diagram which shows the example of a function structure of the encoding apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the structural example of the encoding part which concerns on the same embodiment. It is a schematic block diagram which shows the example of a function structure of the encoding apparatus to which puncturing is applied in the embodiment. It is explanatory drawing which shows the 1st specific example of the encoding part which concerns on the same embodiment. It is a graph which shows the 1st example of the simulation result in the embodiment. It is explanatory drawing which shows the 2nd specific example of the encoding part which concerns on the embodiment. It is a graph which shows the 2nd example of the simulation result in the embodiment. It is explanatory drawing which shows the example of the puncturing matrix in the same embodiment. It is a graph which shows the example of the simulation result including the puncturing in the same embodiment.

Hereinafter, although embodiment of this invention is described, the following embodiment does not limit the invention concerning a claim. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.
FIG. 1 is a schematic block diagram illustrating an example of a functional configuration of an encoding device according to an embodiment of the present invention. As illustrated in FIG. 1, the encoding device 100 includes a data acquisition unit 110, an interleaver 120, two encoding units 130, and a transmission unit 140.

The encoding apparatus 100 acquires and encodes transmission target data having a code alphabet number m and transmits the data with a symbol number ^aq . Here, m and q are both positive integers, a is a prime number, and m <a ^q .
The data acquisition unit 110 acquires data to be transmitted. In particular, the data acquisition unit 110 acquires transmission target data having a code alphabet number m. Then, the data acquiring unit 110, the m code alphabetic transmission target data, finite number of elements a ^q (Galois field) is a one-to-one mapping to the m elements of the elements of GF (a ^q). By this mapping, the data acquisition unit 110 acquires transmission target data having m elements as code alphabets among elements of GF (a ^q ). Then, the data acquisition unit 110 outputs the transmission target data having m elements as code alphabets among the elements of GF (a ^q ) to the encoding unit 130 and the interleaver 120.
In this way, the data acquisition unit 110 acquires transmission target data having the number m of code alphabets associated with a part of the elements of the finite field GF (a ^q ).

Here, GF (a ^q ) is represented as {0, 1, α, α ² ,..., Α ^x-2 } with α as a primitive element. However, x = ^2q . The data acquisition unit 110 converts m alphabets of transmission target data into m elements from 0 to α ^m-2 such as {0, 1, α, α ² ,..., Α ^m-2 }. However, the present invention is not limited to this. Elements for which the data acquisition unit 110 maps the m alphabets of the transmission target data on a one-to-one basis are arbitrary m elements among {0, 1, α, α ² ,..., Α ^x-2 }. Good.
Hereinafter, a case will be described as an example in which the encoding unit 130 performs encoding using a finite field GF (2 ^q ) having 2 ^q elements. However, the finite field used for encoding by the encoding unit 130 is not limited to GF (2 ^q ), and may be GF (a ^q ) with a as a prime number as described above.

The interleaver 120 interleaves the transmission target data mapped by the data acquisition unit 110 to the elements of the finite field GF (2 ^q ) in units of symbols. That is, the interleaver 120 rearranges the transmission target data mapped to the elements of the finite field GF (2 ^q ) by the data acquisition unit 110 in symbol units. The interleaving performed by the interleaver 120 is for enabling iterative decoding, similar to the interleaving in the turbo code. As a method of interleaving performed by the interleaver 120, a known method such as S-random interleaving can be used.

The encoding unit 130 has a recursive structure and performs encoding by a convolution operation using an element of the finite field GF (2 ^q ) as a coefficient. The code alphabet input to the encoding unit 130 is a part of the finite field GF (2 ^q ), whereas the code alphabet output from the encoding unit 130 is all of the finite field GF (2 ^q ). Is an element. The memory used by the encoding unit 130 for the convolution operation stores any element of the finite field GF (2 ^q ). Therefore, the number of states of each memory used by the encoding unit 130 for the convolution operation is the total number of elements of the finite field GF (2 ^q ).

In the following, when the two encoding units 130 are distinguished, reference numerals 130-1 and 130-2 are used as shown in FIG. The encoding unit 130-1 encodes the transmission target data acquired by the data acquisition unit 110 (transmission target data that is not interleaved and represented by an element of the finite field GF (2 ^q )). I do. On the other hand, encoding section 130-2 encodes the transmission target data interleaved by interleaver 120. The encoding unit 130-1 corresponds to an example of a first encoding unit. The encoding unit 130-2 corresponds to an example of a second encoding unit.

The transmission unit 140 outputs the output from the encoding unit 130-1 and the output from the encoding unit 130-2 with a codeword of the number of code alphabets that is the square of the number of code alphabets of the output of one encoding unit 130. Send. That is, transmission section 140 performs transmission using codewords having the number of code alphabets obtained by multiplying the number of code alphabets output from encoding section 130-1 and the number of code alphabets output from encoding section 130-2.
For example, the transmission unit 140, the output of the code alphabet number ^{2 q} from the encoding unit 130-1, an output of the code alphabet number ^{2 q} from the encoding unit ^130-1, and transmits at 2 2q -QAM .

FIG. 2 is an explanatory diagram illustrating a configuration example of the encoding unit 130. In the example of FIG. 2, the encoding unit 130 includes a shift register 131, a recursive convolution operation unit 132a, and a non-recursive convolution operation unit 132b. A combination of the recursive convolution operation unit 132a and the non-recursive convolution operation unit 132b is referred to as a convolution operation unit 132.
In the example of FIG. 2, the recursive convolution operation unit 132a includes P multipliers M1 _{1 to} M1 _P and two adders A1 _{1 to} A1 ₂ . The non-recursive convolution operation unit 132b includes P + 1 multipliers M2 _{0 to} M2 _P and one adder A2. The multiplications performed by each of the multipliers M1 _{1 to} M1 _P and M2 _{0 to} M2 _P and the addition performed by the adders A1 _{1 to} A1 ₂ and A22 are all defined on the finite field GF (2 ^q ). . Therefore, all the calculations performed by the convolution calculation unit 132 are closed by the finite field GF (2 ^q ).

The shift register 131 includes P memories R1 _{1 to} R1 _P. Therefore, the constraint length K of the convolution calculation performed by the encoding unit 130 is K = P + 1. Memory _R1 1 _{~R1 P} is a time series of values that the adder A1 ₂ was calculated stores P times. The memory R1 _p stores a value calculated by the adder A12 ₂ p times before. Here, p is a positive integer satisfying 1 ≦ p ≦ P. In FIG. 2, the value of the adder A1 ₂ was calculated before p times denoted as x _i-p.

Multiplier _M1 p (p is a positive integer of 1 ≦ p ≦ P) is multiplied by a coefficient _{h p} of the value of the memory _{R1 p (x i-p)} . Also, the multiplier M2 ₀ is multiplied by a coefficient _{f 0} to the output of the adder A1 _2. A multiplier M2 _p (p is a positive integer satisfying 1 ≦ p ≦ P) multiplies the value (x _i−p ) of the memory R1 _{p by} a coefficient f _p . Any of the coefficients h _{1 to} h _P and f _{0 to} f _P takes the value of any element of the finite field GF (2 ^q ).
With this configuration, the recursive convolution operation unit 132a performs a convolution operation and adds the operation result to the input symbol u _i . Further, non-recursive convolution computation unit 132b outputs the operation result by performing the convolution operation as an output symbol c _i.

The possible values of the input symbol u _i to the encoding unit 130 are m elements of the finite field GF (2 ^q ), whereas the possible values of the output symbol c _i are the finite field GF (2 ^q The values of the coefficients h _{1 to} h _P and f _{0 to} f _P are determined so as to be all elements of For this purpose, at least _one of the coefficients h _{1 to} h _P is set to a value other than zero. In addition, at least one of the coefficients f _{0 to} f _P is set to a value other than zero.

Thus, the possible values of the input symbol u _i to the encoding unit 130 are m elements of the finite field GF (2 ^q ), whereas the possible values of the output symbol c _i are finite fields. All elements of GF (2 ^q ). Thereby, even if the output is one symbol with respect to one input symbol, the redundancy is added and the coding gain can be obtained.

  Here, when the transmission rate r is defined as in Expression (1), the convolutional code by the encoding unit 130 is the transmission rate 1 (r = 1).

If the number of elements of the input symbol is m = ^2p , the number of transmission bits per output symbol is r × p bits. In addition, the number of trellis states necessary for decoding by the encoding unit 130 is (2 ^q ) ^P = 2 ^{q × P.}

  In addition, with the configuration in which the encoding unit 130 illustrated in FIG. 1 is connected in parallel, the encoding gain can be obtained as described above in any of the encoding units 130-1 and 130-2. For this reason, transmission of systematic elements (systematic symbols) as in the case of a general turbo code is unnecessary in the parallel concatenated encoding in the entire parallel connection configuration shown in FIG. The overall rate after the two encoders 130 are connected in parallel is r = 1/2. While the transmission rate in the case of a general turbo code is 1/3, the transmission rate is improved in the encoding device 100.

In addition, you may make it apply puncturing to the structure of the encoding apparatus 100 shown in FIG. Puncturing here is a process of periodically omitting (deleting) output codeword symbols.
FIG. 3 is a schematic block diagram illustrating an example of a functional configuration of an encoding device to which puncturing is applied. As illustrated in FIG. 3, the encoding device 200 includes a data acquisition unit 110, an interleaver 120, two encoding units 130, a deinterleaver 250, a puncturing processing unit 260, and a transmission unit 140. 3 having the same functions corresponding to those in FIG. 1 are denoted by the same reference numerals (110, 120, 130, 130-1, 130-2, 140), and description thereof is omitted. To do.
The configuration of the encoding device 200 shown in FIG. 3 includes a deinterleaver 250 and a puncturing processing unit 260 in addition to the configuration of the encoding device 100 shown in FIG.

The deinterleaver 250 deinterleaves the interleave performed by the interleaver 120. That is, the deinterleaver 250 performs a conversion reverse to the interleaving performed by the interleaver 120.
The puncturing processing unit 260 performs puncturing on one or both of the output from the encoding unit 130-1 and the output from the deinterleaver 250. That is, the puncturing processing unit 260 performs a process of periodically omitting one or both of the codeword symbol output from the encoding unit 130-1 and the codeword symbol output from the deinterleaver 250. Do.

Note that it is not essential to perform deinterleaving before puncturing on the transmission side as in the case of the encoding apparatus 200 in FIG. 3, and deinterleaving may be performed on the reception side. On the other hand, by performing deinterleaving before puncturing on the transmission side, omission of codeword symbols becomes periodic in the state after deinterleaving. As a result, a decrease in the decoding success rate on the receiving side due to deinterleaving can be reduced.
Puncturing performed by the puncturing processing unit 260 is indicated by a puncturing matrix exemplified by Expression (2).

Each row of the puncturing matrix corresponds to one encoding unit. In the example of Expression (2), the upper row of the puncturing matrix P corresponds to the encoding unit 130-1, and the lower row corresponds to the encoding unit 130-2.
The element “0” of the puncturing matrix indicates that the codeword symbol is omitted, and the element “1” indicates that the codeword symbol is not omitted. In the example of Expression (2), since the elements in the upper row are “1” and “1”, the puncturing processing unit 260 transmits all codeword symbols output from the encoding unit 130-1 to the transmission unit. Output to 140. On the other hand, since the elements in the lower row are “1” and “0”, the encoding apparatus 200 outputs every other codeword symbol output from the encoding unit 130-2 to the transmission unit 140. . In this case, the transmission rate is improved from r = 1/2 to r = 2/3 by puncturing.
Note that the number of columns of the puncturing matrix is called a puncturing period and is represented by T. In the case of the puncturing matrix shown in Equation (2), the puncturing cycle is T = 2.

Next, an encoding simulation result will be described. In the simulation, among the elements of the finite field GF (2 ^q ), the first m symbols {0, 1,... Α ^m−2 } are used as the input code alphabet. Here, m = 2 ^p (p is a positive integer). Therefore, each input symbol has p-bit information.
Three pieces of information of symbol lengths 1024, 2048, and 4096 are used as information to be input to the encoding device (encoding device 100 or 200), and a simulation is performed for each of them. Since the encoding apparatus performs encoding at a rate r = 1/2, output symbol lengths are 2048, 4096, and 8192.

Output symbol is a signal point on the Euclidean space of 2 ^q points. In the following, for the sake of simplicity, one-dimensional PAM (Pulse Amplitude Modulation) is used as a transmission method, and therefore, evaluation is performed based on frequency utilization efficiency (information rate) per one dimension. However, the transmission method used by the encoding device is not limited to the one-dimensional PAM, and various transmission methods can be used. For example, frequency efficiency can be doubled by assigning PAM to a two-dimensional plane (complex plane) (that is, using QAM (Quadrature Amplitude Modulation) as a transmission scheme).

For the output symbol lengths of 2048 and 4096, S random interleavers having spread values of 22, 32, and 45 are used as interleavers. Further, the encoding unit 130 has a memory number 1 (P = 1, and therefore a constraint length 2).
For decoding, a BCJR algorithm using a trellis structure of codes is used in the same manner as decoding of ordinary binary turbo codes. However, the calculation of the metric needs to be performed in the finite field GF (2 ^q ). Here, since P = 1, the number of states of the trellis used for decoding is 2 ^q.
For the coefficients used in the multiplier of the encoding unit 130, all possible combinations of coefficients are simulated to search for all solutions, and the combination of coefficients that minimizes the error rate is used.

Trellis termination processing is performed by repeatedly transmitting the final state four times. Therefore, in the configuration in which the encoding units are connected in parallel, termination processing is performed by additionally transmitting 8 symbols in total. By this termination processing, the block length becomes 2056, 4054, 8200.
Hereinafter, puncturing is not performed in the simulation described with reference to FIGS. 4 and 5 and the simulation described with reference to FIGS. 6 and 7. On the other hand, in the simulation described with reference to FIGS. 8 and 9, puncturing is performed.

FIG. 4 is an explanatory diagram illustrating a first specific example of the encoding unit 130. The encoding unit 130 illustrated in FIG. 4 is a specific example of the encoding unit 130 illustrated in FIG. 2, and the same reference numerals (130, 131, 132, 132a, 132b, R1 ₁ , M1 ₁ , M2 ₀ , M2 ₁ , A1 ₂ , A2).

In the example of FIG. 4, the recursive convolution portion 132a, the multiplier M1 ₁ is multiplied by a coefficient alpha ² of the value of the memory R1 _1. The adder A1 ₂ adds an output from the multiplier M1 ₁ to the input symbol _{u i.} Memory R1 ₁ stores the previous value of the output from the adder A1 _2.
In non-recursive convolution unit 132b, a multiplier M2 ₀ is multiplied by a coefficient α ⁰ (= 1) to the output from the adder A1 _2. The multiplier M2 ₁ multiplies the coefficient alpha ³ of the value of the memory R1 _1. The adder A2 adds the output of the multiplier M2 _{0 and} the output of the multiplier M2 ₁ . The output of the multiplier M2 ₁ is an output _{c i} of the encoder 130.

In the example of FIG. 4, the input is a symbol of m = 4 (p = 2 bits), and the input code alphabet is {0, 1, α, α ² }. The encoding unit 130 converts this input symbol into an output symbol (q = 3) on GF (8). The output code alphabet is {0, 1, α, α ² ,..., Α ⁶ }. The encoding apparatus 100 maps the output code alphabet to 8-PAM modulation. Each trellis has 8 states.
The coefficient shown in FIG. 4 is a coefficient that shows the best result in the constraint length 2 when the primitive polynomial g (x) = x ³ + x + 1.
In the example of FIG. 4, the frequency use efficiency per dimension is p / 2 = 1 (bit / dimension) excluding the termination processing symbols.

FIG. 5 is a graph showing a first example of a simulation result. The horizontal axis of FIG. 5 represents a signal-to-noise ratio (SNR) [unit: decibel (dB)]. The vertical axis represents the frame error rate (FER). FIG. 5 shows the relationship between the signal-to-noise ratio and the frame error rate in a communication simulation using the encoding unit 130 configured as shown in FIG.
A line L11 indicates the channel capacity under the signal point constraint when the frequency utilization efficiency is 1 bit / dimension and the 8-PAM signal point arrangement is used. A line L21 indicates a frame error rate at the block length 2048. A line L22 indicates a frame error rate with a block length of 4096. A line L23 indicates a frame error rate at a block length of 8192.

As indicated by line L23, a frame error rate of 10 ⁻² can be achieved with a signal-to-noise ratio 0.75 dB away from the limit (line L11) at block length 8200. In addition, an error floor is observed as in a normal turbo code, but this is below the frame error rate of 10 ⁻² .
Also, as shown by lines L21 and L22, a good frame error rate is obtained even when the input symbol length is relatively short.

FIG. 6 is an explanatory diagram illustrating a second specific example of the encoding unit 130. The encoding unit 130 shown in FIG. 6 has the same configuration as that of FIG. 4, and the coefficient values used by the multipliers are different. In the configuration of FIG. 6, the coefficients of the multipliers M1 ₁ , M2 ₀ and M2 ₁ are set to α ² , α ⁹ and α ⁰ (= 1), respectively.
In the example of FIG. 6, the input is a symbol of m = 8 (p = 3 bits), and the input code alphabet is {0, 1, α, α ² ,..., Α ⁶ }. The encoding unit 130 converts this input symbol into an output symbol (q = 4) on GF (16). The output code alphabet is {0, 1, α, α ² ,..., Α ¹⁴ }. The encoding apparatus 100 maps the output code alphabet to 16-PAM modulation.
The coefficient shown in FIG. 6 is a coefficient that shows the best result in the constraint length 2 when the primitive polynomial g (x) = x ⁴ + x + 1.
In the example of FIG. 6, the frequency utilization efficiency per dimension is p / 2 = 1.5 (bit / dimension) excluding the symbols for termination processing.

FIG. 7 is a graph showing a second example of the simulation result. The horizontal axis of FIG. 7 represents the signal-to-noise ratio [unit: dB]. The vertical axis represents the frame error rate. FIG. 7 shows the relationship between the signal-to-noise ratio and the frame error rate in a communication simulation using the encoding unit 130 configured as shown in FIG.
A line L31 indicates the channel capacity under the signal point constraint when the frequency utilization efficiency is 1.5 bits / dimension and the 16-PAM signal point arrangement is used. A line L41 indicates the frame error rate at the block length 2048. A line L42 indicates the frame error rate at the block length 4096. A line L43 indicates a frame error rate at a block length of 8192.

As indicated by line L43, a frame error rate of 10 ⁻² can be achieved with a signal-to-noise ratio of 0.9 dB away from the limit (line L31) at block length 8200. In addition, an error floor is observed as in a normal turbo code, but this is below the frame error rate of 10 ⁻² .
Also, as shown by lines L41 and L42, a good frame error rate is obtained even when the input symbol length is relatively short.

FIG. 8 is an explanatory diagram illustrating an example of a puncturing matrix. In the simulation described with reference to FIG. 8 and FIG. 9, a simulation including puncturing is performed using the encoding unit 130 having the configuration illustrated in FIG. A simulation was performed for each of the two types of puncturing shown in FIG.
In puncturing (transmission rate 2/3, frequency utilization efficiency 1.3 bits / dimension) shown in row L51 in FIG. 8, the number of transmission symbols is 3072. In the puncturing (transmission rate 4/5, frequency utilization efficiency 1.6 bit / dimension) shown in the row L52, the number of transmission symbols is 2560.

FIG. 9 is a graph illustrating an example of a simulation result including puncturing. The horizontal axis of FIG. 9 represents the signal-to-noise ratio [unit: dB]. The vertical axis represents the frame error rate.
A line L61 indicates the channel capacity under signal point constraint when puncturing is not performed (transmission rate 1, frequency utilization efficiency 1 bit / dimension, 8-PAM). In this case, the number of output symbols is 4096.
A line L62 indicates the channel capacity under signal point constraint in the case of puncturing (transmission rate 2/3, frequency utilization efficiency 1.3 bits / dimension, 8-PAM) in the row L51.
A line L63 indicates the channel capacity under signal point constraint in the case of puncturing (transmission rate 4/5, frequency utilization efficiency 1.6 bit / dimension, 8-PAM) in the row L52.

A line L71 indicates a frame error rate when puncturing is not performed. A line L72 indicates the frame error rate when the puncturing of the row L51 is performed. A line L73 indicates a frame error rate when the puncturing of the row L52 is performed.
In either case, good results have been obtained, and the transmission rate can be easily changed without degrading the error rate characteristics by applying puncturing. In any case, the frame error rate is 10 ⁻² within 1 dB from the limit (lines L61, L62, L63).
As described above, good results were obtained even when puncturing was performed.

As described above, the data acquisition unit 110 acquires the transmission target data of the number of code alphabets associated with a part of the elements of the finite field. The encoding unit 130 has a recursive structure and performs encoding by a convolution operation using the elements of the finite field as coefficients. The number of code alphabets output from the encoding unit 130 and the number of states of each memory of the encoding unit 130 are all the number of elements of a finite field.
Thereby, in the encoding performed by the encoding unit 130, even if the output is one symbol with respect to one input symbol, the redundancy is added and the encoding gain can be obtained. With this coding gain, when the coding unit 130 is used for coding for iterative decoding, systematic transmission of elements is not necessary. In terms of iterative decoding, the error correction capability is high, and transmission efficiency is high in that transmission of systematic elements is unnecessary.
Thus, according to encoding apparatuses 100 and 200, communication with high error correction capability and higher transmission efficiency is possible.

Here, in the previous application (Japanese Patent Application No. 2016-130872), the applicant performs the first encoding using a convolution operation in which a binary symbol is input and an L-ary symbol that is binary or higher is output. An encoding unit; a conversion unit that converts an L-ary symbol sequence output from the first encoding unit into an L-order square matrix element sequence; an interleaver that interleaves an L-order square matrix element sequence; , A second encoding unit that performs a convolution operation that receives an element interleaved by the interleaver as an input and outputs an element of an L-order square matrix and feeds back the output of the convolution operation to the input side of the convolution operation And proposed an encoding device.
In the encoding apparatus according to the previous application, there is room for further improvement in transmission efficiency in that encoding using binary symbols as input is performed.
On the other hand, in the encoding apparatus according to the present embodiment, excellent transmission efficiency can be obtained using non-binary symbols. In the encoding apparatus according to the present embodiment, since the encoding unit has a feedback structure, it is possible to obtain a high error correction capability with a configuration in which the encoding units are connected in parallel.

In addition, binary turbo codes and LDPC codes are powerful error correction codes close to the Shannon limit when a sufficiently long code length is sufficiently long, but error rate characteristics for medium to short code lengths. Is not good. Furthermore, when using a modulation scheme composed of multi-level signal points in order to improve frequency utilization efficiency, the error rate characteristics greatly depend on how binary codes are mapped to multi-level modulation.
On the other hand, the non-binary symbol (multi-ary symbol) used by the encoding apparatus according to the present embodiment is only when the code length (input symbol length) is long as described with reference to FIGS. In addition, even if it is relatively short, the effect of having an excellent error correction capability can be obtained.

In addition, the encoding unit 130-1 performs encoding on the transmission target data acquired by the data acquisition unit 110. The interleaver 120 interleaves the transmission target data acquired by the data acquisition unit 110. Encoding section 130-2 encodes the transmission target data interleaved by interleaver 120.
As a result, iterative decoding can be performed on the decoding side, and no systematic element transmission is required for iterative decoding. In terms of iterative decoding, the error correction capability is high, and transmission efficiency is high in that transmission of systematic elements is unnecessary.
Thus, according to encoding apparatuses 100 and 200, communication with high error correction capability and higher transmission efficiency is possible.

Further, the transmission unit 140 includes a transmission unit that performs transmission with a codeword of the number of code alphabets obtained by multiplying the number of code alphabets output from the encoding unit 130-1 and the number of code alphabets output from the encoding unit 130-2. Prepare.
Thereby, according to the encoding apparatuses 100 and 200, the output from the encoding parts 130-1 and 130-2 can be matched with a transmission symbol comparatively easily.

It should be noted that a program for realizing all or some of the functions and operations performed by the encoding apparatus 100 or 200 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is stored in a computer system. The processing of each unit may be performed by reading and executing. Here, the “computer system” includes an OS and hardware such as peripheral devices.
Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention.

100, 200 Encoder 110 Data acquisition unit 120 Interleaver 130 Encoding unit 140 Transmission unit 250 Deinterleaver 260 Puncturing processing unit

Claims (3)

A data acquisition unit that acquires transmission target data of a code alphabet number that is associated with a part of a finite field element number of prime integer powers;
An encoding unit that has a recursive structure and performs encoding by a convolution operation using coefficients of the elements of the finite field;
With
The encoding device, wherein the number of code alphabets output from the encoding unit and the number of states of each memory of the encoding unit are all the total number of elements of the finite field. A first encoding unit that performs the encoding on the transmission target data acquired by the data acquisition unit;
An interleaver that interleaves the transmission target data acquired by the data acquisition unit;
A second encoding unit that performs the encoding on the transmission target data interleaved by the interleaver;
The encoding device according to claim 1, comprising:   The transmission part which transmits by the code word of the number of code alphabets which multiplied the number of code alphabets of the output of the said 1st encoding part and the number of code alphabets of the output of the said 2nd encoding part is provided. The encoding device described in 1.

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