QC-LDPC codes and their performance on Power Line Communications Channel

In this paper Low Density Parity Check Codes (LDPC) are introduced in the Power Line Communications Channel (PLC). We investigate how different decoding algorithms, which are applied on LDPC codes, affect the system´s performance. Therefore, an iterative belief propagation decoding algorithm as well as a proposed variation of the original bit flipping algorithm are exploited. In addition, a hybrid technique combining these two algorithms is proposed. Irregular LDPC codes of various code rates are studied. Specifically, the cases of 1/2, 1/3, 2/3, 3/4 and 4/5 code rates are investigated. Regarding the irregular LDPC codes, they are constructed in a Quasi-Cyclic form. The system´s performance is expressed in terms of the resultant Bit Error Rate (BER) versus the Signal to Noise Ratio (SNR). In order to design the power line communications channel, Middleton´s class A noise model is used to account for the system´s background and impulsive noise, while Zimmermann´s channel model is also used. The OFDM transmission technique is taken into account. Results are derived via computer simulations.