Low density parity check encoder using costas array, and channel encoder of high speed portable internet system comprising the same and channel encoding method

1. A Low Density Parity Check code (LDPC) encoder using LDPC comprising:

a Costas array generator for generating an n×n Costas array of n dots having one dot in every row and column, wherein n is a natural number;

at least two shift registers for shifting the Costas array generated by the Costas array generator;

a parity check matrix generator for generating an analogous circulation parity check matrix, in which a same data pattern is repeated, from the shifted data; and

an encoding part for performing encoding by using the parity check matrix generated by the parity check matrix generator.

2. The LDPC encoder of claim 1 , wherein the Costas array generator generates the Costas array by selecting prime number α of Galois field GF(p) for a prime number p, and inserting a dot in a cell (i,j) of the n×n array fulfilling the following equation below:

i=α j (mod p )1≦ i≦n −1, 0≦ j≦n− 1.

3. The LDPC encoder of claim 1 , wherein the Costas array generator modifies the Costas array according to a variable input length.

4. The LDPC encoder of claim 1 , wherein the LPDC is constructed with binary elements, and is a regular LDPC of which row and column weights are the same with each other.

5. A channel encoder of a portable Internet system comprising:

a Media Access Control (MAC) layer connector for performing a connection with a MAC layer;

a padding unit for receiving data from the MAC layer and padding the received data to be fitted to a code block length;

a Cyclic Redundancy Check (CRC) unit for adding a CRC bit to the padded data;

an encoder for encoding the CRC bit added data; and

an interleaver for channel-interleaving the encoded data,

wherein the encoder encodes by selectively using any one of a convolution encoder, a turbo encoder, and a Low Density Parity Check code (LDPC) encoder, wherein the LDPC encoder encodes by using an analogous circulation parity check matrix generated on the basis of a Costas array.

6. The channel encoder of claim 5 , wherein the LDPC encoder comprises:

a Costas array generator for generating an n×n Costas array of n dots having one dot in every row and column, wherein n is a natural number;

at least one shift register for shifting the Costas array generated by the Costas array generator;

a parity check matrix generator for generating an analogous circulation parity check matrix, in which a same data pattern is repeated, from the shifted data; and

an encoding part for performing encoding by using the parity check matrix generated by the parity check matrix generator.

7. The channel encoder of claim 5 further comprising a symbol selector for enabling support of a hybrid automatic request and a Hybrid Automatic Repeat Request (HARQ) service by selecting a symbol.

8. A channel encoding method of a portable Internet system, the method comprising:

generating, by a Costas array generator, an n×n Costas array of n dots having one dot in every row and column, wherein n is a natural number;

generating, by a parity check matrix generator, an analogous circulation parity check matrix having a repeated same data pattern by shifting the generated Costas array at least twice; and

performing, by an encoding part, an encoding by using the generated parity check matrix.

9. The channel encoding method of claim 8 , wherein the generating of the n×n Costas array comprises:

selecting a prime number α of Galois field GF(p) for a prime number p;

generating the Costas array by inserting a dot in a cell (i,j) of the n×n array fulfilling an equation i=α j (mod p) 1≦i≦n−1, 0≦j≦n−1; and

modifying the Costas array according to a variable input length.