LDPC Decoder Architecture

Vikram Arkalgud Chandrasetty, Syed Mahfuzul Aziz

Mong‐Kai Ku, Huan-Sheng Li, Yi-Hsing Chien

Low-density parity-check (LDPC) codes have been widely considered as error-correcting codes for next generation communication systems. A good LDPC decoder design requires both implementation friendly LDPC codes and efficient decoder architectures. The quality of LDPC code is crucial in determining the coding gain and implementation complexity of LDPC hardware decoders. This paper presented a genetic algorithm (GA) based LDPC code search algorithm with hardware considerations. Regular quasi-cyclic LDPC codes are used due to its friendliness to hardware implementation. Our hardware architecture design schedules pipeline LDPC decoding operation to boost the hardware utilization efficiency (HUE) of LDPC decoder. A LDPC decoder with a block size of 12288 is implemented in FPGA to validate our code and architecture design.

Yongmei Dai, Ning Chen, Zhiyuan Yan

In this paper, we first propose parallel turbo-sum-product (PTSP) and turbo-shuffled-sum-product (TSSP) decoding algorithms for partly parallel decoder architectures of quasi-cyclic (QC) low-density parity-check (LDPC) codes. Our proposed algorithms not only achievefasterconvergenceandbettererrorperformancethan the sum-product (SP) decoding algorithm, but also needlessmemoryin implementation. Then we propose a partly parallel decoder architecture based on our PTSP algorithm and implement it using FPGA. Our PTSP decoder architecture achievessignificantlyhigherthroughputand requireslessmemorythan previously proposed decoder architectures with the same FPGA and LDPC code. Finally, to further reduce the memory requirement, we also propose a partly parallel decoder architecture based on our TSSP algorithm.

Valentin Savin

Christiane Beuschel

In recent years, the amount of digital data which is stored and transmitted for private and public usage has increased considerably. To allow a save transmission and storage of data despite of error-prone transmission media, error correcting codes are used. A large variety of codes has been developed, and in the past decade low-density parity-check (LDPC) codes which have an excellent error correction performance became more and more popular. Today, low-density parity-check codes have been adopted for several standards, and efficient decoder hardware architectures are known for the chosen structured codes. However, the existing decoder designs lack flexibility as only few structured codes can be decoded with one decoder chip. In consequence, different codes require a redesign of the decoder, and few solutions exist for decoding of codes which are not quasi-cyclic or which are unstructured. In this thesis, three different approaches are presented for the implementation of fully programmable LDPC decoders which can decode arbitrary LDPC codes. As a design study, the first programmable decoder which uses a heuristic mapping algorithm is realized on a field-programmable gate array (FPGA), and error correction curves are measured to verify the correct functionality. The main contribution of this thesis lies in the development of the second and the third architecture and an appropriate mapping algorithm. The proposed fully programmable decoder architectures use one-phase message passing and layered decoding and can decode arbitrary LDPC codes using an optimum mapping and scheduling algorithm. The presented programmable architectures are in fact generalized decoder architectures from which the known decoder architectures for structured LDPC codes can be derived.