LDPC

Dependencies

In order to use the module you need to install the following dependencies: bitstring and numpy.

How to use the module

In the begining of your python code import the functions you intend to use, as follow

from ldpc.py import encode, decode

How to generate a block code?

Start by importing the generate_code function.

This function receives 3 inputs

• k: size of the message to code
• m: number of times each message bit is gonna be used
• v: number of bits needed to generate a parity bit

The function returns a list of size m(k/v) with lists of size v

Example:

k = 9
m = 2
v = 2
P = generate_code(k, m, v)

How to code a message?

Start by importing the encode function.

The function receives 3 inputs

• k : size of the message to code
• P : block code (see generate_code function)
• w : message to code

The function returns a BitArray with the message w, with the parity bits concatenated.

Example:

k = 32
m = 8
v = 4
w = BitArray('0b01001000010001110111100010010101')
P = generate_code(k, m, v)
x = encode(k, P, w)

How to decode a coded message?

Start by importing the decode function

The function needs 4 arguments:

• k : size of the message to code
• P : block code (see generate_code function)
• y : code received from the Binary Eraser Channel
• q : errors detected in y

The function returns a BitArray with the message w decoded or None if it's not possible to decode.

Example:

k = 8
m = 2
v = 2
P = generate_code(k, m, v)
y = BitArray('0b0001000101101100')
q = BitArray('0b1110101000000010')
x = decode(k, P, y, q)