Implementation of the Low complexity and High throughput LDPC Decoder

Wen Ji, 32134

Kon‐Woo Kwon, Kwang-Ok Kim, Kyeong-Hwan Doo +2 more

We propose a hardware architecture for 50G-PON LDPC decoder achieving high throughput and high error correcting capability while maintaining low level of resource utilization and implementation complexity. Our approach employs phased decoding as a key algorithm which effectively balances the competing goals of high throughput and low amount of resource utilization. We also propose a fixed-structured wiring network between variable nodes and check nodes, leveraging the quasi-cyclic property of parity-check matrix to significantly reduce implementation complexity. To further simplify the decoder structure and enhance the throughput, we propose a blockwise column cyclic shift in the parity-check matrix, along with rules for normalizing and quantizing messages generated in decoder. Our design also incorporates a pipelined structure of computation units. By integrating the proposed design schemes, we draw a sophisticated architecture for high-speed and low-complexity LDPC decoder that achieves the seamless decoding throughput of 49.7664 Gbps, even on a single FPGA board.

Adrian Voicila, David Declercq, François S. Verdier +2 more

Z. Cui, Zhirui Wang Zhirui Wang, Xiaofang Zhang

Layered decoding is well appreciated in low-density parity-check (LDPC) decoder implementation since it can achieve effectively high decoding throughput with low computation complexity. This work, for the first time, addresses low-complexity column-layered decoding schemes and very-large-scale integration (VLSI) architectures for multi-Gb/s applications. At first, the min-sum algorithm is incorporated into the column-layered decoding. Then algorithmic transformations and judicious approximations are explored to minimise the overall computation complexity. Compared to the original column-layered decoding, the new approach can reduce the computation complexity in check node processing for high-rate LDPC codes by up to 90% while maintaining the fast convergence speed of layered decoding. Furthermore, a relaxed pipelining scheme is presented to enable very high clock speed for VLSI implementation. Equipped with these new techniques, an efficient decoder architecture for quasi-cyclic LDPC codes is developed and implemented with 0.13 µm VLSI implementation technology. It is shown that a decoding throughput of nearly 4 Gb/s at a maximum of 10 iterations can be achieved for a (4096, 3584) LDPC code. Hence, this work has facilitated practical applications of column-layered decoding and particularly made it very attractive in high-speed, high-rate LDPC decoder implementation.

Massimo Rovini, Luca Fanucci, Francesco Rossi

Sun Shu long, Lin Min

Non-Binary Low-Density-Parity-Check codes (NB-LDPC) have shown superior performance but its huge complexity and low throughput prevent it from practical applications. This paper presents a novel architecture to implement a kind of high-throughput low-complexity irregular quasi-cyclic NB-LDPC decoder over GF (16) based on Extended Min-Sum (EMS) Algorithm. Double clocks are adopted in this paper. The low frequency clock at 60 MHz serves as the system clock and the high frequency clock at 480 MHz works for check nodes and variable nodes thus they can be reused 8 times during one system clock period as a result the complexity can be largely reduced. Synthesis result shows that the throughput can achieve 68.57 Mbps at 5 iterations. FPGA testing result shows that the decoder has little performance degradation compared with its floating model and it can provide about 0.5 dB coding gain compared with its binary LDPC code of the same block length. The proposed architecture can be conveniently extended to higher Galois Filed such as GF (64) or GF (256) and it can be applied for different code length and rate by modifying a slight part of the decoder. Compared with previous works, the decoder proposed in this paper is more efficient for practical applications.