dvbsLDPCPCM

Generate parity-check matrix for DVB-S2/S2X LDPC codes

Since R2024b

Syntax

H = dvbsLDPCPCM(r)

H = dvbsLDPCPCM(r,frameType)

H = dvbsLDPCPCM(r,frameType,outputFormat)

Description

H = dvbsLDPCPCM(r) returns a parity-check matrix, H, of the low-density parity-check (LDPC) code with code rate r from the Digital Video Broadcasting Satellite Second Generation (DVB-S2) or Digital Video Broadcasting Satellite Second Generation extended (DVB-S2X) standard.

H = dvbsLDPCPCM(r,frameType) specifies the DVB-S2/S2X frame type.

H = dvbsLDPCPCM(r,frameType,outputFormat) specifies the format for the output parity-check matrix.

Examples

Generate DVB-S2 LDPC Parity-Check Matrix and Encode Data

Create a parity-check matrix for a 2/3 code rate DVB-S2 LDPC code.

pcmatrix = dvbsLDPCPCM("2/3");

Configure the Communications Toolbox™ LDPC encoder using the parity-check matrix.

cfgLDPCEnc = ldpcEncoderConfig(pcmatrix);

Generate random information bits as a binary column vector, where the number of bits matches the number of information bits for the encoder configuration.

infoBits = rand(cfgLDPCEnc.NumInformationBits,1) < 0.5;

Produce the codeword by encoding the information bits using the LDPC encoder configuration.

codeword = ldpcEncode(infoBits,cfgLDPCEnc);

Input Arguments

r — DVB-S2/S2X LDPC code rate

"1/4", "1/3", "2/5" | ...

DVB-S2/S2X LDPC code rate, specified as one of these options.

• Applicable for DVB-S2 — "1/4", "1/3", "2/5", "1/2", "3/5", "2/3", "3/4", "4/5", "5/6", "8/9", or "9/10".

• Applicable for DVB-S2X — In addition to the code rates applicable for DVB-S2, DVB-S2X also supports these code rates.

  "2/9", "13/45", "9/20", "90/180", "96/180", "11/20", "100/180", "104/180", "26/45", "18/30", "28/45", "23/36", "116/180", "20/30", "124/180", "25/36", "128/180", "13/18", "132/180", "22/30", "135/180", "140/180", "7/9", "154/180", "1/5", "11/45", "4/15", "14/45", "7/15", "8/15", and "32/45".

Data Types: char | string

frameType — DVB-S2/S2X frame type

"normal" | "medium" | "short"

DVB-S2/S2X frame type, specified as one of these values.

• "normal" — Sets the LDPC code block length to 64,800 bits.

• "medium" — Sets the LDPC code block length to 32,400 bits.

• "short" — Sets the LDPC code block length to 16,200 bits.

If frameType is not specified for an input code rate, the function sets it as the next largest available frame type.

To determine the frame types supported for a specified code rate, see Tips.

Data Types: char | string

outputFormat — Output format

"sparse" (default) | "indices"

Output format for parity-check matrix H, specified as one of these two values.

• "sparse" — The function returns H as a sparse logical matrix.

• "indices" — The function returns H as a two-column, double-precision matrix that defines the row and column indices of the 1s in H.

Data Types: char | string

Output Arguments

H — Parity-check matrix

matrix

Parity-check matrix, returned as a matrix.

Data Types: double | logical

Tips

The table indicates the valid frameType values for each input code rate r.

Code Rate	Frame Type	Reference Standard
1/4	normal, short	DVB-S2/S2X
1/3	normal, short
	medium	DVB-S2X
1/4	normal, short	DVB-S2/S2X
2/5
1/2
3/5
2/3
3/4
4/5
5/6
8/9
9/10	normal
2/9		DVB-S2X
13/45
9/20
90/180
96/180
11/20
100/180
104/180
26/45	normal, short
18/30	normal
28/45
23/36
116/180
20/30
124/180
25/36
128/180
13/18
132/180
22/30
135/180
140/180
7/9
154/180
11/45	short, medium
4/15	short
14/45
7/15
8/15
32/45
1/5	medium

References

[1] ETSI Standard EN 302 307-1 V1.4.1 (2014-11). Digital Video Broadcasting (DVB); Second Generation Framing Structure, Channel Coding and Modulation Systems for Broadcasting, Interactive Services, News Gathering and other Broadband Satellite Applications (DVB-S2).

[2] ETSI Standard EN 302 307-2 V1.1.1(2015-11). Digital Video Broadcasting (DVB); Second Generation Framing Structure, Channel Coding and Modulation Systems for Broadcasting, Interactive Services, News Gathering and other Broadband Satellite Applications; Part 2: DVB-S2 Extensions (DVB-S2X).

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

You must specify the outputFormat argument as a constant. Depending on the output type requirement, this argument must be coder.Constant('sparse') or coder.Constant('indices').

Version History

Introduced in R2024b

R2025a: Generate parity check matrix for DVB-S2X LDPC codes

The dvbsLDPCPCM function now supports generation of parity check matrix for DVB-S2X codes, in addition to DVB-S2.