A communication apparatus is disclosed including a processor that performs a first encoding procedure to generate a first sequence of encoded bits from a first sequence of bits, and performs a second encoding procedure to generate a second sequence of encoded bits from a sequence of known bits; and a second sequence of bits comprising the first sequence of bits and the first sequence of encoded bits; and a transmitter that transmits a signal generated from the second sequence of encoded bits, wherein the second sequence of encoded bits is determined based on a length of the second sequence of bits.