Mitigation of Impulsive Noise Effect on the PLC Channel With QC–LDPC Codes as the Outer Coding Scheme

摘要

In this paper, the characteristics of irregular quasicyclic—low-density parity check (QC–LDPC) codes are examined when they are applied on a highly impulsive noise channel, such as the power-line-communications (PLC) channel. We study two decoding algorithms: 1) the sum product and 2) the bit—flipping algorithm, and how they affect the system's performance. LDPC codes are introduced in combination with other coding schemes, such as Reed-Solomon and convolutional codes. We propose irregular QC–LDPC codes as outer codes for the PLC channel in combination with Reed—Solomon codes, due to their decoding characteristics. In addition, various code rates are used for each different coding scenario. We also test how common Reed—Solomon codes affect the system's performance, such as the RS(63, 53), RS(511, 431), RS(127, 107), and RS(255, 239) codes. Furthermore, we propose an altered version of the sum—product decoding algorithm to enable its operation when QC–LDPC codes are used as the outer coding scheme in combination with Reed—Solomon codes. Regarding the system's design, the orthogonal frequency-division multiplexing transmission technique is utilized. We also take Zimmermann's model into consideration for the PLC channel and Middleton's noise model.