A LDPC code/decode channel coding model based on sum-product algorithm realization via LabVIEW

In this work the basic concept of low-density parity-check codes is presented. First discovered in early 1960´s, but were out of use because of their computing complexity for that time, today they are used in communication systems that take advantage of parallelism, very good error correction and high throughput like the DVB-S2. A soft decision sum-product algorithm based low-density parity-check code/decode channel coding model was developed through use of National Instruments´ LabVIEW. This model was used to test the influence of the number of bits used in a message to be sent, the number of iterations and the low-density parity-check code rate on communication quality and the bit error rate. Simulation results show that the increase of message bits improves the communication quality. To achieve a better communication (lower BER) the code rate should be reduced but the number of iteration of the LDPC decoder should be set to a higher value.