Low Density Parity- Check (LDPC) codes are a class of linear block codes which provide good error detection and error correction capabilities and are capable of achieving near Shannon- limit channel communication. Hence, they are included as error correction codes in many modern communication system standards like Digital Video Broadcasting (DVB-S2), Gigabit Ethernet (10GBASE-T) and WiMax. In this book, we bring together several of approaches for construction of LDPC codes and we examine them from structural point of view. We have designed a simulation tool for the performance evaluation of LDPC codes in terms their Bit Error Rate and Block Error Rate. The influence of the type of LDPC codes on the decoding performance is also investigated using simulations. This allows us to differentiate and select an appropriate LDPC code according to performance, latency, decoding complexity, and memory requirements. Thus this tool can aid a designer to test his LDPC code under different parameters and also choose a particular LDPC matrix with desired error correction requirements.