A method of decoding a received signal encoded with an LDPC code is provided. The method comprises initializing bits with an initial value of the received signal, obtaining posterior values of the bits by iteratively decoding the bits in a row direction and a column direction, determining on the basis of the posterior values whether an iterative decoding operation should be performed and comparing the posterior values with predetermined values and updating the initial value of the bits, when it is determined that the iterative decoding operation is be performed.