CN103023512A - Device and method for generating constant coefficient matrix in ATSC system RS coding - Google Patents

Abstract

The invention provides a generation scheme of a constant coefficient matrix in ATSC system RS coding, which is characterized in that a generation device of the constant coefficient matrix mainly comprises six parts, namely a controller, a field element binary representation lookup table, a basis transformation matrix memory, an inverse basis transformation matrix memory, a multiplication operation unit and a storage unit. The invention removes 1120 times of multiplication and 980 times of addition related to the construction of a multiplier matrix, and for each generated polynomial coefficient, only the binary representation of corresponding continuous 8 field elements is taken out from the field element binary representation lookup table to construct the multiplier matrix, thereby generating the constant coefficient matrix. The method has low calculation amount, is easy to realize, and can obviously improve the generation speed of the constant coefficient matrix.

Description

Generating apparatus and the method for constant coefficient matrix in the RS of the ATSC system coding

Technical field

The present invention relates to digital television broadcasting (Advanced Television Systems Committee, ATSC) technology, particularly the generation method of constant coefficient matrix in a kind of ATSC RS of system coding.

Background technology

Reed---Suo Luomen (Reed-Solomon, RS) code is the multi-system BCH code that a class has very strong error correcting capability, and it can correct random error also can correct error burst, is widely used in Modern Communication System.

The ATSC system has adopted cascaded code, and ISN is grid coding (Trellis Coded Modulation, TCM), and outer code is finite field gf (2 ⁸) on (207,187) system Shorten RS code.Fig. 1 has provided the generator polynomial coefficient g of RS (207,187) code _i(0≤i＜20), g _iRepresent with the power representation.

The structure of parallel RS encoder as shown in Figure 2, it mainly is comprised of shift register, finite field adder and Galois field multiplier, its implementation complexity depends on Galois field multiplier to a great extent.Prior art adopts matrix to connect and takes advantage of UV (g _i) W realizes finite field multiplier, wherein matrix U and matrix W depend on and adopt which kind of reciproccal basis, constant multiplier matrix V (g _i) generation be the design key.For finite field gf (2 ⁸), multiplier matrix V (g _i) dimension be 8 * 8, for each generator polynomial coefficient g _i, prior art need to be carried out 1 computing of tabling look-up and be obtained matrix V (g _i) the first row element, then carry out 7 complex calculation and obtain respectively matrix V (g _i) all the other 7 row elements, the average calculating operation amount that each complex calculation comprises is 8 multiplication and 7 sub-additions.The ATSC system has 20 generator polynomial coefficients, and therefore, existing method need to be carried out 20 computings of tabling look-up, 20*7*8=1120 multiplication and 20*7*7=980 sub-addition.As seen the method amount of calculation of existing structure multiplier matrix is large, brings thus the slow shortcoming of constant coefficient matrix formation speed.

Summary of the invention

For the large technical disadvantages of structure multiplier matrix computations amount that the RS of ATSC system coding exists, the invention provides a kind of method of quick generation constant coefficient matrix, effectively reduce the amount of calculation that matrix generates, improve the formation speed of constant coefficient matrix.

As shown in Figure 4, the generating apparatus of constant coefficient matrix mainly is comprised of controller, field element binary representation look-up table, basic transition matrix memory, contrary basic transition matrix memory, multiplying unit, memory cell six parts.The generative process of whole constant coefficient matrix divided for five steps finished: the first step, generate field element binary representation look-up table according to primitive polynomial, the index of look-up table is the power j of field element, wherein, 0≤j＜255, the content of the every row of look-up table are the binary representation of field element; Second step, controller is with l(generator polynomial coefficient g _iThe power representation be α ^l) from field element binary representation look-up table, read continuous 8 field element α for index ^l, α ^L+1..., α ^L+7Binary representation consist of multiplier matrix V (g _i), adopt the circulation reading manner when reading, if l+7〉254, namely capable during to table footline less than 8 row from l, then then read from heading capable (the 0th row), until read the binary representation of 8 field elements; In the 3rd step, controller reads contrary basic transition matrix U, U and V (g _i) finish multiplication UV (g in the multiplying unit _i), gained product T (g _i) write storage unit; In the 4th step, controller reads basic transition matrix W, with the product median T (g in the memory cell _i) finish multiplication T (g in the multiplying unit _i) W, the gained product is multiplier matrix Z (g _i); The 5th step, repeat second and third, four steps, obtain the constant coefficient matrix of all 20 generator polynomial coefficients.

As fully visible, compare with existing solution, 20*7*8=1120 multiplication that the present invention has removed that structure multiplier matrix relates to and 20*7*7=980 sub-addition are for each generator polynomial coefficient g _i, the binary representation that only needs to take out corresponding continuous 8 field elements from field element binary representation look-up table can be constructed its multiplier matrix, and then generates the constant coefficient matrix, and amount of calculation is low, is easy to realize, can obviously improve the formation speed of constant coefficient matrix.

Can be further understood by ensuing detailed description and accompanying drawings about the advantages and spirit of the present invention.

Description of drawings

Fig. 1 has provided generator polynomial coefficient g _i(g _iRepresent with the power representation)

Fig. 2 is the structured flowchart of parallel RS encoder;

Fig. 3 has provided the simplified flow chart that generates the constant coefficient matrix;

Fig. 4 has provided the generating apparatus functional block diagram of constant coefficient matrix;

Fig. 5 has provided the binary representation of part field element;

Fig. 6 has compared the operand of two kinds of constant coefficient matrix generation schemes.

Embodiment

The invention will be further described below in conjunction with the drawings and specific embodiments, but not as a limitation of the invention.

Computing in the RS encoder is all finished in galois field, galois field GF (2 ^m) in arbitrary element Q can with the base 1, α ..., α ^M-1}={ γ ₀, γ ₁..., γ _M-1Represent, we claim this base to be Standardizing Base.Usually with { γ ₀, γ ₁..., _M-1Represent GF (2 ^m) on Standardizing Base.If other one group of base { τ ₀, τ ₁..., τ _M-1Satisfy:

$\mathrm{Tr}\left({\mathrm{\γ}}_i{\mathrm{\τ}}_j\right)=\mathrm{\δ}(i,j)=\left\{\begin{array}{cc}1& i=j\\ 0& i\≠j\end{array}\right.---\left(1\right)$

Wherein:

Be called the Trace function.Then claim base { τ ₀, τ ₁..., τ _M-1Be base { γ ₀, γ ₁..., γ _M-1Reciproccal basis.GF (2 so ^m) in arbitrary element Q can be expressed as:

$Q=\underset{i=0}{\overset{m-1}{\mathrm{\Σ}}}{q}_i{\mathrm{\γ}}_i=\underset{i=0}{\overset{m-1}{\mathrm{\Σ}}}{q}_i^{\mathrm{\τ}}{\mathrm{\τ}}_i---\left(2\right)$

Q wherein _iWith

Be respectively the coordinate of Standardizing Base and reciproccal basis.Reciproccal basis coordinate and Standardizing Base coordinate can be changed mutually, and conversion can be with matrix representation as shown in the formula (3), (4).

The Standardizing Base coordinate turns the reciproccal basis coordinate:

$\left[\begin{array}{c}{\mathrm{<figure-callout\; id="0"\; label="q"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">q</figure-callout>}}_0^{\mathrm{\&tau;}}\\ q_1^{\mathrm{\&tau;}}\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ q_{m-1}^{\mathrm{\&tau;}}\end{array}\right]=\left[\begin{array}{cccccc}{\mathrm{<figure-callout\; id="0"\; label="w"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{0,0}}& {\mathrm{<figure-callout\; id="0"\; label="w"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{0,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& w_{0,m-1}\\ w_{\mathrm{1,0}}& w_{\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& w_{1,m-1}\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ w_{m-\mathrm{1,0}}& w_{m-\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& w_{m-1,m-1}\end{array}\right]\left[\begin{array}{c}{q}_0\\ q_1\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ q_{m-1}\end{array}\right]=W\left[\begin{array}{c}{q}_0\\ q_1\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ q_{m-1}\end{array}\right]---\left(3\right)$

Wherein W is basic transition matrix, is expressed as follows:

$W=\left[\begin{array}{cccccc}{\mathrm{<figure-callout\; id="0"\; label="w"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{0,0}}& {\mathrm{<figure-callout\; id="0"\; label="w"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{0,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& w_{0,m-1}\\ w_{\mathrm{1,0}}& w_{\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& w_{1,m-1}\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ w_{m-\mathrm{1,0}}& w_{m-\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& w_{m-1,m-1}\end{array}\right]$

The reciproccal basis coordinate turns the Standardizing Base coordinate:

$\left[\begin{array}{c}{q}_0\\ q_1\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ q_{m-1}\end{array}\right]=\left[\begin{array}{cccccc}{u}_{\mathrm{0,0}}& u_{\mathrm{0,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& u_{0,m-1}\\ u_{1,0}& u_{\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& u_{1,m-1}\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ u_{m-\mathrm{1,0}}& u_{m-\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& u_{m-1,m-1}\end{array}\right]\left[\begin{array}{c}{\mathrm{<figure-callout\; id="0"\; label="q"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">q</figure-callout>}}_0^{\mathrm{\&tau;}}\\ q_1^{\mathrm{\&tau;}}\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ q_{m-1}^{\mathrm{\&tau;}}\end{array}\right]=\mathrm{<figure-callout\; id="0"\; label="U\; q"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">U</figure-callout>}\left[\begin{array}{c}{q}_{}^{}\end{array}\right]\left[\begin{array}{c}{}_0^{\mathrm{\&tau;}}\\ q_1^{\mathrm{\&tau;}}\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ q_{m-1}^{\mathrm{\&tau;}}\end{array}\right]---\left(4\right)$

Wherein U is contrary basic transition matrix, is expressed as follows:

$U=\left[\begin{array}{cccccc}{u}_{\mathrm{0,0}}& u_{\mathrm{0,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& u_{0,m-1}\\ u_{\mathrm{1,0}}& u_{\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& u_{1,m-1}\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ u_{m-\mathrm{1,0}}& u_{m-\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& u_{m-1,m-1}\end{array}\right]$

For 0≤j≤m-1, we can obtain an important inference:

$\mathrm{Tr}\left({\mathrm{\&alpha;}}^{j}Q\right)=\mathrm{Tr}\left({\mathrm{\&alpha;}}^j\underset{i=0}{\overset{m-1}{\mathrm{\&Sigma;}}}{q}_i^{\mathrm{\&tau;}}{\mathrm{\&tau;}}_i\right)=\underset{i=0}{\overset{m-1}{\mathrm{\&Sigma;}}}{q}_i^{\mathrm{\&tau;}}\mathrm{Tr}\left({\mathrm{\&alpha;}}^j{\mathrm{\&tau;}}_i\right)=q_j^{\mathrm{\&tau;}}---\left(5\right)$

Suppose A, B, C ∈ GF (2 ^m), C=AB, wherein A is expressed as with Standardizing Base B, C are expressed as with reciproccal basis $B=\underset{i=0}{\overset{m-1}{\mathrm{\&Sigma;}}}{b}_i^{\mathrm{\&tau;}}{\mathrm{\&tau;}}_i,$ $C=\underset{i=0}{\overset{m-1}{\mathrm{\&Sigma;}}}{c}_i^{\mathrm{\&tau;}}{\mathrm{\&tau;}}_i.$ Can be got by formula (5):

$b_i^{\mathrm{\&tau;}}=\mathrm{Tr}\left({\mathrm{\&alpha;}}^{i}B\right)---\left(6\right)$

$c_i^{\mathrm{\&tau;}}=\mathrm{Tr}\left({\mathrm{\&alpha;}}^{i}C\right)=\mathrm{Tr}\left({\mathrm{\&alpha;}}^i\mathrm{AB}\right)=\mathrm{Tr}\left(\left({\mathrm{\&alpha;}}^{i}A\right)B\right)---\left(7\right)$

Because A ∈ GF (2 ^m), so α ⁱA ∈ GF (2 ^m), α ⁱA can be expressed as

V wherein _{I, j}(0≤j＜m) is α ⁱA is at GF (2 ^m) on binary representation.Will

Bringing formula (7) into gets:

$c_i^{\mathrm{\&tau;}}=\mathrm{Tr}\left(\left({\mathrm{\&alpha;}}^{i}A\right)B\right)=\mathrm{Tr}\left(\underset{j=0}{\overset{m-1}{\mathrm{\&Sigma;}}}{v}_{i,j}{\mathrm{\&alpha;}}^{j}B\right)$

$=\underset{j=0}{\overset{m-1}{\mathrm{\&Sigma;}}}\mathrm{Tr}\left(v_{i,j}{\mathrm{\&alpha;}}^{j}B\right)=\underset{j=0}{\overset{m-1}{\mathrm{\&Sigma;}}}{v}_{i,j}\mathrm{Tr}\left({\mathrm{\&alpha;}}^{j}B\right)$

$=\underset{j=0}{\overset{m-1}{\mathrm{\&Sigma;}}}{v}_{i,j}{b}_j^{\mathrm{\&tau;}}---\left(8\right)$

$=[v_{i,0}{v}_{i,1}\&CenterDot;\&CenterDot;\&CenterDot;v_{i,m-1}]\left[\begin{array}{c}{\mathrm{<figure-callout\; id="0"\; label="b"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">b</figure-callout>}}_0^{\mathrm{\&tau;}}\\ b_1^{\mathrm{\&tau;}}\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ b_{m-1}^{\mathrm{\&tau;}}\end{array}\right]$

We can get by formula (8):

$\left[\begin{array}{c}{\mathrm{<figure-callout\; id="0"\; label="c"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">c</figure-callout>}}_0^{\mathrm{\&tau;}}\\ c_1^{\mathrm{\&tau;}}\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ c_{m-1}^{\mathrm{\&tau;}}\end{array}\right]=\left[\begin{array}{cccccc}{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">v</figure-callout>}}_{\mathrm{0,0}}& v_{\mathrm{0,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& v_{0,m-1}\\ v_{\mathrm{1,0}}& v_{\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& v_{1,m-1}\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ v_{m-\mathrm{1,0}}& v_{m-\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& v_{m-1,m-1}\end{array}\right]\left[\begin{array}{c}{v}_0^{\mathrm{\&tau;}}\\ b_1^{\mathrm{\&tau;}}\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ b_{m-1}^{\mathrm{\&tau;}}\end{array}\right]=V\left(A\right)\left[\begin{array}{c}{\mathrm{<figure-callout\; id="0"\; label="b"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">b</figure-callout>}}_0^{\mathrm{\&tau;}}\\ b_1^{\mathrm{\&tau;}}\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ b_{m-1}^{\mathrm{\&tau;}}\end{array}\right]---\left(9\right)$

Wherein V (A) is the multiplier matrix, is expressed as follows:

$V\left(A\right)=\left[\begin{array}{cccccc}{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="HDA00002749173200022.png,HDA00002749173200031.png"\; state="\{\{state\}\}">v</figure-callout>}}_{\mathrm{0,0}}& v_{\mathrm{0,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& v_{0,m-1}\\ v_{\mathrm{1,0}}& v_{\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& v_{1,m-1}\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ \&CenterDot;& \&CenterDot;& & \&CenterDot;& & \&CenterDot;\\ v_{m-\mathrm{1,0}}& v_{m-\mathrm{1,1}}& \&CenterDot;& \&CenterDot;& \&CenterDot;& v_{m-1,m-1}\end{array}\right]$

I row element v in the multiplier matrix V (A) _{I, 0}, v _{I, 1}..., v _{I, m-1}α ⁱA is at GF (2 ^m) on binary representation, i+1 row element v _I+1,0, v _I+1,1..., v _{I+1, m-1}α ^I+1A=(α ⁱA) α is at GF (2 ^m) on binary representation.The power representation of supposing multiplier A is α ^l, the m row element of matrix V (A) is respectively α so ^l, α ^L+1..., α ^L+m-1At GF (2 ^m) on binary representation.

For ATSC system, m=8.The former multinomial of RS code book is p (x)=x ⁸+ x ⁴+ x ³+ x ²+ 1.Make p (α)=0, get α ⁸=α ⁴+ α ³+ α ²+ 1.Fig. 5 has provided the binary representation of part field element, and as can be seen from the figure, each element is that a upper element multiply by α.For the coding of RS (207,187) code, the multiplier of multiplication is generator polynomial coefficient g _i(0≤i＜20), for example for the constant term of generator polynomial, multiplier A=g ₀=α ¹⁹⁰=α ¹+ α ²+ α ³+ α ⁵+ α ⁷, we need only and sequentially take out continuous 8 field element α ¹⁹⁰, α ¹⁹¹..., α ¹⁹⁷At GF (2 ⁸) on binary representation can obtain multiplier matrix V (α ¹⁹⁰) as shown in the formula (10).

$V\left({\mathrm{\&alpha;}}^{190}\right)=\left[\begin{array}{cccccccc}0& 1& 1& 1& 0& 1& 0& 1\\ 1& 0& 0& 0& 0& 0& 1& 0\\ 0& 1& 0& 0& 0& 0& 0& 1\\ 1& 0& 0& 1& 1& 0& 0& 0\\ 0& 1& 0& 0& 1& 1& 0& 0\\ 0& 0& 1& 0& 0& 1& 1& 0\\ 0& 0& 0& 1& 0& 0& 1& 1\\ 1& 0& 1& 1& 0& 0& 0& 1\end{array}\right]---\left(10\right)$

Derive and to get by formula (3), (4), (9)

$\left[\begin{array}{c}{c}_0\\ c_1\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ c_{m-1}\end{array}\right]=\mathrm{UV}\left(A\right)W\left[\begin{array}{c}{b}_0\\ b_1\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ b_{m-1}\end{array}\right]=Z\left(A\right)\left[\begin{array}{c}{b}_0\\ b_1\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ b_{m-1}\end{array}\right]---\left(11\right)$

Z (A)=UV (A) W wherein.We just obtain determining constant coefficient g like this _iConstant coefficient matrix Z (g _i).Easily prove constant coefficient matrix Z (g _i) for the coefficient g that determines _iBe unique, that is to say, no matter adopt which kind of reciproccal basis, Z (g _i) all fix, so this method does not need to seek optimum reciproccal basis, we can adopt any one reciproccal basis, such as triangular basis, thereby obtain corresponding basic transition matrix W and contrary basic transition matrix U.

According to formula (11) and multiplier matrix V (g _i) design feature, the present invention designs a kind of generating algorithm of constant coefficient matrix, concrete steps are as follows:

The first step generates field element binary representation look-up table according to primitive polynomial, and the index of look-up table is the power of field element, and the content of the every row of look-up table is the binary representation of field element.

Second step is with l(generator polynomial coefficient g _iThe power representation be α ^l) from field element binary representation look-up table, read continuous 8 field element α for index ^l, α ^L+1..., α ^L+7Binary representation consist of multiplier matrix V (g _i), adopt the circulation reading manner when reading, if l+7〉254, namely capable during to table footline less than 8 row from l, then then read from heading capable (the 0th row), until read the binary representation of 8 field elements.

In the 3rd step, finish matrix and even take advantage of UV (g _i) W, can obtain coefficient g _iConstant coefficient matrix Z (g _i).

Fig. 3 generates constant coefficient matrix Z (g _i) simplified flow chart.

Existing method is identical with the first, the 3rd step of algorithm of the present invention, and the way of second step is first with l(generator polynomial coefficient g _iThe power representation be α ^l) from field element binary representation look-up table, read α for index ^lThereby binary representation obtain multiplier matrix V (g _i) the first row element, then carry out 7 complex calculation and obtain respectively multiplier matrix V (g _i) all the other 7 row elements.As seen existing method will be carried out 7 computings for each coefficient more, and the average calculating operation amount that each complex calculation comprises is 8 multiplication and 7 sub-additions.The ATSC system has 20 generator polynomial coefficients, and therefore, existing method needs carry out 20*7*8=1120 multiplication and 20*7*7=980 sub-addition more, and the operand of two kinds of constant coefficient matrix generation schemes as shown in Figure 6.

According to above-mentioned rigorous derivation, we have drawn multiplier matrix V (g _i) design feature, based on these characteristics, the invention provides a kind of device of quick generation constant coefficient matrix, as shown in Figure 4.This constant coefficient matrix generation device realizes simple, mainly is comprised of controller, field element binary representation look-up table, basic transition matrix memory, contrary basic transition matrix memory, multiplying unit, memory cell six parts.The reading of the reading of controller control look-up table, basic transition matrix, contrary reading with matrix of basic transition matrix connect multiplication.The binary representation of field element binary representation look-up table stores field element, the index of table are the power j of field element, wherein, and 0≤j＜255.Base transition matrix memory stores matrix W.Contrary basic transition matrix memory stores matrix U.Multiplying unit realization matrix connects takes advantage of UV (g _i) W.The cell stores matrix connects the intermediate object program T (g that takes advantage of _i).

The present invention has designed the generation method of constant coefficient matrix in the following RS coding:

The first step generates field element binary representation look-up table according to primitive polynomial, and the index of look-up table is the power j of field element, wherein, 0≤j＜255, the content of the every row of look-up table is the binary representation of field element.

Second step, controller is with l(generator polynomial coefficient g _iThe power representation be α ^l) from field element binary representation look-up table, read continuous 8 field element α for index ^l, α ^L+1..., α ^L+7Binary representation consist of multiplier matrix V (g _i), adopt the circulation reading manner when reading, if l+7〉254, namely capable during to table footline less than 8 row from l, then then read from heading capable (the 0th row), until read the binary representation of 8 field elements.

In the 3rd step, controller reads contrary basic transition matrix U, U and V (g _i) finish multiplication UV (g in the multiplying unit _i), gained product T (g _i) write storage unit.

In the 4th step, controller reads basic transition matrix W, with the product median T (g in the memory cell _i) finish multiplication T (g _i) W, the gained product is constant coefficient matrix Z (g _i).

In the 5th step, repeat second and third, four steps obtained the constant coefficient matrix of all 20 coefficients.

As fully visible, compare with existing solution, 20*7*8=1120 multiplication that the present invention has removed that structure multiplier matrix relates to and 20*7*7=980 sub-addition are for each generator polynomial coefficient g _i, the binary representation that only needs to take out corresponding continuous 8 field elements from field element binary representation look-up table can be constructed its multiplier matrix, and then generates the constant coefficient matrix, and amount of calculation is low, is easy to realize, can obviously improve the formation speed of constant coefficient matrix.

Below through the specific embodiment and the embodiment the present invention is had been described in detail, some distortion that those skilled in the art carries out in the technical solution of the present invention scope and improvement all should be included in protection scope of the present invention.

Claims (4)

1. the generating apparatus of constant coefficient matrix during the RS of ATSC system encodes, constant coefficient matrix Z (g _i)=UV (g _i) W, wherein U is contrary basic transition matrix, W is basic transition matrix, V (g _i) be the multiplier matrix, g _i(0≤i＜20) for generating polynomial coefficient, the ATSC system adopts finite field gf (2 ⁸) on (207,187) system Shorten RS code, the former multinomial of RS code book is p (x)=x ⁸+ x ⁴+ x ³+ x ²+ 1, RS code has 20 generator polynomial coefficients, it is characterized in that, described device comprises with lower member:

Controller, be used for the reading of the reading of control look-up table, basic transition matrix, contrary basic transition matrix read and matrix connects storage that multiplication, matrix connect the intermediate object program of taking advantage of and reads;

Field element binary representation look-up table is for the binary representation of storage field element;

Base transition matrix memory is used for storing basic transition matrix W;

Contrary basic transition matrix memory is used for the contrary basic transition matrix U of storage;

The multiplying unit is used for realization matrix and even takes advantage of UV (g _i) W;

Memory cell is used for storage matrix and connects the intermediate object program T (g that takes advantage of _i)=UV (g _i).

2. constant coefficient matrix generation device as claimed in claim 1 is characterized in that, the index of described field element binary representation look-up table is the power j of field element, wherein, 0≤j＜255, the content that each memory cell is preserved is the binary representation of field element.

3. constant coefficient matrix generation device as claimed in claim 1 is characterized in that, described multiplying unit is used for realization matrix and even takes advantage of UV (g _i) W:

Matrix U multiply by matrix V (g _i), gained product T (g _i) be stored in memory cell;

T (g _i) multiply by matrix W, the gained product is constant coefficient matrix Z (g _i).

4. the generation method of constant coefficient matrix during a parallel RS encodes, constant coefficient matrix Z (g _i)=UV (g _i) W, wherein U is contrary basic transition matrix, W is basic transition matrix, V (g _i) be the multiplier matrix, g _i(0≤i＜20) for generating polynomial coefficient, the ATSC system adopts finite field gf (2 ⁸) on (207,187) system Shorten RS code, the former multinomial of RS code book is p (x)=x ⁸+ x ⁴+ x ³+ x ²+ 1, RS code has 20 generator polynomial coefficients, it is characterized in that, said method comprising the steps of:

(1) generate field element binary representation look-up table according to primitive polynomial, the index of look-up table is the power j of field element, wherein, 0≤j＜255, the content of the every row of look-up table is the binary representation of field element;

(2) controller is with l(generator polynomial coefficient g _iThe power representation be α ^l) from field element binary representation look-up table, read continuous 8 field element α for index ^l, α ^L+1..., α ^L+7Binary representation consist of multiplier matrix V (g _i), adopt the circulation reading manner when reading, if l+7〉254, namely capable during to table footline less than 8 row from l, then then read from heading capable (the 0th row), until read the binary representation of 8 field elements;

(3) controller reads contrary basic transition matrix U, U and V (g _i) finish multiplication UV (g in the multiplying unit _i), gained product T (g _i) write storage unit;

(4) controller reads basic transition matrix W, with the product median T (g in the memory cell _i) finish multiplication T (g in the multiplying unit _i) W, the gained product is constant coefficient matrix Z (g _i);

(5) repeating step (2), (3), (4) obtain the constant coefficient matrix of all 20 coefficients.

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