A method is provided for channel encoding in a communication system using an LDPC code. The method includes encoding input bits using a BCH code, shortening bits of the encoded input bits according to a number of bit groups to be shortened and an order among a plurality of orders according to which the bit groups are shortened, wherein the number of bit groups to be shortened is based on a number of bits to be shortened, which is based on a number of the encoded input bits, encoding information bits including the encoded input bits and the shortened one or more bits, using an LDPC code to generate parity bits, puncturing bits in the parity bits based on a puncturing parameter among puncturing parameters, and transmitting a signal generated from the encoded information bits based on the punctured bits. The plurality of orders being based on the puncturing parameters and including first and second orders.