Encoding apparatus and method using turbo code, and permutation unit and method

A permutation unit, comprising:

• a first permutation unit that mutually exchanges bits of at least two blocks among three blocks when a sequence of 3 bits inputted from the three blocks each of which is formed of N bits respectively, is a multiple of 2;
• a second permutation unit that confirms a remainder values obtained by dividing the sequence of the mutually exchanged 3 bits by 4 and changes the sequence of the 3 bits within the three blocks in a different manner according to the remainder values;
• and
• an enumeration unit that permutates and enumerates the sequence of the bits of the three blocks in the changed sequence.

An encoding, with a hardware encoder, method using a turbo code, comprising:

• encoding 3 bits inputted from first to third blocks respectively each of which is formed of N bits, with recursive systematic convolutional codes to output a first parity bit;
• permutating the 3 bits in a predetermined manner;
• encoding the permutated 3 bits with the recursive systematic convolutional codes to output a second parity bit;
• and
• optionally removing the first parity bit and the second parity bit to control a coding rate when a mother coding rate according to a combination of the 3 bits, the first parity bit, and the second parity bit is different from a predetermined coding rate.

A method of permutation, comprising:

• confirming, with hardware, a sequence k (k is a constant that is 0≦k≦N) of 3 bits when the 3 bits of a first block, a second block, and a third block, each of which is formed of N bits is respectively inputted in parallel;
• mutually exchanging at least 2 bits among the 3 bits of the three blocks when the sequence of the 3 bits is a multiple of 2;
• confirming a remainder values obtained by dividing the sequence of the 3 bits by 4 and changing the sequence of the mutually exchanged 3 bits within the three blocks in a different manner according to the remainder values;
• and
• permutating and enumerating the sequence of bits of the three blocks in the changed sequence.