LDPC Encoder implementation using VHDL

[RAVI30]

Hi...
I implementing LDPC encoder for DVB-T2 as per the DVB-T2 standards....
Plz help me....

specification r as per standard....

 

[TrickyDicky]

WHat do you need help with?

 

[RAVI30]

in that calculation of address of the array and xoring the calculated address location signal to Input data and again it assign to the that location only........ like this i need to calculate around 8 process in one clock cycle only....
i not getting how to do this..... i have tryied but it is not assigning the all 8 value to respected address ... only one value is assigning...

 

[TrickyDicky]

post the code, lets see the problem...

 

[RAVI30]

LDPC is implemented as per the standard:

The LDPC encoder treats the output of the outer encoding, I = ( i0 , i1,...,iKldpc −1) as an information block of size Kldpc Nbch , and systematically encodes it onto a codeword Λ of size Nldpc , where:


The task of the encoder is to determine Nldpc − Kldpc parity bits ( p0 , p1,..., pnldpc −kldpc −1) for every block of Kldpc information bits, ( i0 , i1,...,ikldpc −1) The procedure is as follows:

• Initialize p0 = p1 = p2 = ... = pNldpc −Kldpc −1 = 0

• Accumulate the first information bit, i0 , at parity bit addresses specified in the first row of tables A.1 through A.6. For example, for rate 2/3 ,

p317 = p317 xor i0 p6700 = p6700 xor i0
p2255 = p2255 xor i0 p9101= p9101 xor i0
p2324 = p2324 xor i0 p10057 = p10057 xor i0
p2723 = p2723 xor i0 p12739= p12739 xor i0
p3538 = p3538 xor i0 p17407 = p17407 xor i0
p3576 = p3576 xor i0 p21039 = p21039 xor i0
p6194 = p6194 xor i0


• For the next 359 information bits, im, m =1, 2, ..., 359 accumulate im at parity bit addresses
{x *mmod360*Qldpc}mod(Nldpc -Kldpc ) where x denotes the address of the parity bit accumulator corresponding to the first biti i0 , and Qldpc is a code rate dependent constant specified in table 8(a). Continuing with the example, Qldpc 60 for rate 2/3. So for example for information bit i1, the following operations are performed:

p377 =p377 xori1 p6760=p6760 xor i1

p2315 =p2315 xor i1 p9161=p9161 xor i1

p2384=p2384 xor i1 p10117 =p10117 xor i1

p2783=p2783 xor i1 p12799 =p12799 xor i1

p3598 =p3598 xor i1 p17467 =p17467 xor i1

p3636=p3636 xor i1 p21099=p21099 xor i1

p6254 =p6254 xor i1

• For the 361st information bit i360 , the addresses of the parity bit accumulators are given in the second row of the tables A.1 through A.6. In a similar manner the addresses of the parity bit accumulators for the following 359 information bits im, m = 361, 362, ..., 719 are obtained using the formula {x + (mmod360)×Qldpc}mod(Nldpc − Kldpc ) where x denotes the address of the parity bit accumulator corresponding to the information bit i360 , i.e. the entries in the second row of the tables A.1 through A.6.

• In a similar manner, for every group of 360 new information bits, a new row from tables A.1 through A.6 are used to find the addresses of the parity bit accumulators.

................................................................................

this given in as per standard so need to implement this...

 

[TrickyDicky]

This is just the standard, but you havent posted the problem.