Method for puncturing a low density parity check code

A method for puncturing a Low Density Parity Check (LDPC) code that is expressed in a factor graph configured by a bit node and a check node connected to an edge and is configured in a systematic region and a parity region, comprising the steps of:

• a) setting a codeword length and the total number of bit nodes to be punctured;
• b) selecting a check node (or check nodes) with highest priority excluding check nodes completely checked in a current round;
• c) selecting a bit node (or bit nodes) with a highest priority excluding bit nodes completely checked among bit nodes connected to the selected check node (or check nodes);
• d) determining whether the selected bit node is a bit node to be punctured, that is, it is not systematic, not set by a puncturing prohibition flag;
• e) puncturing an associated bit node if the selected bit node is the bit node to be punctured, setting unpunctured bit nodes connected to the selected check node by a puncturing prohibition flag, decreasing the number of remained bit nodes to be punctured by 1 and increasing the number of connected punctured node of associated check node by 1;
• f) determining whether the number of remaining bits to be punctured is greater than 0;
• and
• g) returning to step b) if the number of remaining bits to be punctured is greater than 0, and ending a puncturing process if the number of remaining bits to be punctured is not greater than 0.