Abstract—In this paper, we consider iterative detection and decoding (i.e., turbo equalization) for nonbinary low-density parity-check (LDPC) coded partial-response channels, where a quantizer is present to discretize the continuous received signal. We propose a turbo equalizer that uses the pre-computed quantized channel transition probabilities in the symbol-level BCJR channel detection algorithm, which significantly reduces the computational complexity by avoiding real-time floating-point multiplications. The proposed approach is further extended to nonbinary LDPC coded bit-patterned media recording (BPMR) channels. Simulation results show that with a small number of quantization bits, the proposed receiver approaches closely the performance of the conventional turbo equalizer operating on unquantized signals.
Index Terms—BCJR algorithm, nonbinary LDPC codes, quantization, turbo equalization.
Nina Zhang and Luyan Xing are with Weihai Beiyang Optic-Electronic Info-Tech Co. Ltd., China (e-mail: {zhangnina; xingluyan }@beiyang.com).
Zhiliang Qin, Yingying Li, Qidong Lu, and Xiaowei Liu are with Weihai Beiyang Electrical Group Co., Ltd, Weihai, Shandong, China (e-mail: {zhangnina, qinzhiliang, liyingying, luqidong, liuxiaowei}@beiyang.com).
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Cite: Nina Zhang, Zhiliang Qin, Yingying Li, Luyan Xing, Qidong Lu, and Xiaowei Liu, "Quantized Turbo Equalization for Non-binary LDPC Coded Partial-Response Channels," International Journal of Future Computer and Communication vol. 10, no. 1, pp. 13-17, 2021.
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