A Brief Overview of Different LDPC Code

This paper corresponds to a brief survey of LDPC codes. Many error detection and correction codes have been studied. There are vast classes of such codes; some of them are hamming codes, turbo codes, BCH codes and LDPC codes. But among these codes LDPC codes achieve better performance and lower decoding complexity. LDPC codes were originally discovered by Robert G. Gallager. But after the rediscovery of LDPC codes by Mackay and Neal in 1995 interest on LDPC codes increases because of its bit error performance approaches asymptotically the Shannon limit. An LDPC code is a special class of linear block codes whose parity-check matrix H has low density of ones i.e. sparse. Due to this sparsity in LDPC codes there is low complexity decoding and its implementation is also simple. Also LDPC codes provides large degree of parallelism that can be exploited in the decoder and in LDPC codes information block length are long enough. In addition LDPC codes provides wide range of trade-offs between performance and complexity. A major drawback of LDPC codes is their high encoding complexity.LDPC codes find its application in many areas such as satellite transmission of digital television. LDPC codes also used for 10 GBase-T Ethernet which sends data at 10 gigabits per second over twisted pair cable.