Abstract

In spite of their powerful error correcting capability, Low Density Parity Check codes (LDPC) have been ignored due to their high complexity. Around three decades after the invention of this code, researchers returned back their attention to it and tried to make some significant improvements in complexity. As the result, the LDPC codes were widely considered in the next generation error correcting codes in telecommunication systems. In 2005, the new standard for Digital Video Broadcasting (DVB-S2) used LDPC codes as its channel coding scheme. The features of the above mentioned code allow a transmission near the Shannon limit. In this thesis, we first review the LDPC codes in general, and then we present the encoding and decoding scheme which is used in the DVB-S2 standard. We discuss regular and irregular LDPC codes and compare the advantages and disadvantages of these codes with each other. In this thesis, we consider a higher block length for the LDPC code compared to DVB-S2 standard to improve the performance. We propose an efficient hybrid parity check matrix for this code. This parity check matrix has the same number of base addresses as the case for DVB-S2 which processes high block length with the same complexity. At the end, simulation results are provided to show the improvement in the performance