a forward error correction method for decoding coded bits transmitted over a radio channel after being generated by encoding binary bits with low density parity check matrixes . the method comprises converting each of the coded bits into a log likelihood ratio value indicating a ratio of probability of zero to probability of one , and applying the converted values to variable nodes ; delivering messages applied to the variable nodes to check nodes connected to the variable nodes ; checking a message having a minimum value among the messages delivered from the variable nodes , and determining a sign of the message having the minimum value ; receiving messages updated in the check nodes , adding up signs of the received messages and a sign of an initial message , applying a weighting factor of 1 when all signs are identical , and when all signs are not identical , updating a message of a variable node by applying a weighting factor having a predetermined value to the sum of messages received from all other check nodes and adding a initial value to the weighted sum ; determining llr of an initial input value ; and hard - deciding values of the variable nodes , performing parity check on the hard decision values , and stopping the decoding when no error occurs as a result of the parity check .