Reduced Complexity Window Decoding of Spatially Coupled LDPC Codes for Magnetic Recording Systems

Spatially coupled low-density parity-check (SC-LDPC) codes have emerged to possess capacity-approaching performance. The SC-LDPC codes can be decoded by a sliding window, therefore, the decoding latency and complexity of SC-LDPC codes are lower than those of underlying LDPC codes when the codeword length is very large. In this paper, the SC-LDPC decoder with the sliding window is employed in turbo equalization of magnetic recording systems. We examine the bit error rates (BERs) of the output of the sliding window during the iterative decoding, and then observe that the consecutive code blocks have approximately the same BERs. Herein, to reduce decoding complexity of SC-LDPC codes, the consecutive code blocks can be considered as the output of SC-LDPC codes. In addition, the non-uniform schedule update is adopted in the window decoding to avoid unnecessary updates within a window. The simulation results show that the proposed decoding algorithms applied in bit-patterned media magnetic recording systems can achieve a significant reduction in complexity compared to the traditional decoding without any loss in BER performance.