Efficient design of multi-rate low-density parity-check code decoder

Ling Zhao, Xiaolin Zhang, Zhi Gang

Youyao Liu, Haimei Huang, Jialei Gao +1 more

Low Density Parity Check Code (LDPC) can meet the decoding requirements of a variety of code lengths and rates in different communication scenarios, but the LDPC code check matrix is irregular, which has problems with difficult storage and reading of the check matrix and high coding complexity. For the decoding requirements of multi-code length, this paper proposes a Quasi Crystal Low Density Parity Check Codes (QCLDPC) code based on Fibonacci Lucas sequence, which can obtain the codewords with different code length and code rate by changing the number of rows and columns of the exponential matrix. In terms of decoding algorithms, the Layered Non-Maximum Suppression (LNMS) decoding algorithm, which combines the minimum sum decoding algorithm with the layered algorithm, is proposed to improve the convergence speed of decoding iteration and decoder throughput. Through simulation and comparative experiments, it is proved that this design can support a variety of bit rates, block lengths and sub matrix sizes, and meet the requirements of high throughput and low complexity decoder in modern communication systems.

Andres I. Vila Casado, Wen-Yen Weng, Stefano Valle +1 more

This paper describes and analyzes low-density parity-check code families that support variety of different rates while maintaining the same fundamental decoder architecture. Such families facilitate the decoding hardware design and implementation for applications that require communication at different rates, for example to adapt to changing channel conditions. Combining rows of the lowest-rate parity-check matrix produces the parity-check matrices for higher rates. An important advantage of this approach is that all effective code rates have the same blocklength. This approach is compatible with well known techniques that allow low-complexity encoding and parallel decoding of these LDPC codes. This technique also allows the design of programmable analog LDPC decoders. The proposed design method maintains good graphical properties and hence low error floors for all rates.

Florent Pirou

Zhe Zhang, Liang Zhou, Junyi Du +1 more

In this paper, we propose an algebraic approach to design extremely low rate low-density parity-check (LDPC) codes by employing the primitive polynomials. We first investigate the requirements for the polynomials to construct 4-cycle free LDPC codes and then propose an algebraic approach to design the parity check matrix. To achieve a better decoding performance in the extremely low rate region, we propose an extension method to construct more check nodes and virtual variable nodes to obtain more constraints. Our designed LDPC codes have simple encoding and simple decoding features. Simulation results show that our proposed rate-0.03 LDPC code can achieve 2.2 dB gain, compared to the LDPC code designed by the progressive edge growth algorithm with the optimized edge degree distributions described in [7].

Daesun Oh, Keshab K. Parhi