天基物联多码率QC-LDPC码构造方法研究

Research on the Construction Method of Multi-rate QC-LDPC Codes for Space-based IoT

摘要:

针对天基物联场景中的小数据传输进行多码率QC-LDPC码研究，结合5G标准中LDPC码校验矩阵的设计方法与DVB-S2X标准中不同码率条件下编码长度不变的特性，探索适用于卫星通信中针对短码在固定编码长度条件下实现多码率QC-LDPC码的设计方案，并进行仿真验证；其中，校验矩阵是通过基于代数法的QC-LDPC码的叠加构造方法进行设计，结合缩短与扩展操作来构造具有固定编码长度且能实现多码率的循环移位矩阵，该矩阵同时保持了5G LDPC编码标准中的类Raptor结构；最后通过所设计方案与IEEE802.11n标准进行误比特率仿真对比，根据仿真结果显示，所设计方案与IEEE802.11n标准性能相差较小，且误比特率能到10-7，达到了预期的效果。

Abstract:

The study of multi-rate quasi-cyclic low-density parity-check (QC-LDPC) codes for small data transmission in space-based internet of things (IOT) scenarios, combined with the design method of LDPC code check matrix in 5G standard and the characteristics of fixed code length under different code rate conditions in digital video broadcasting’s second generation satellite television broadcasting standard extensions (DVB-S2X) standard, explores the design scheme applicable to the implementation of multi-rate QC-LDPC codes for short codes in satellite communications under fixed code length conditions, and conducts simulations to verify; the scheme is validated by simulation. The check matrix is designed by the algebraic method of QC-LDPC code superposition construction, combining shortening and expansion operations to construct a circular shift matrix with fixed coding length and multiple code rates, which maintains the Raptor-like structure of the 5G LDPC coding standard; finally, the designed scheme is compared with the IEEE802.11n standard for error According to the simulation results, the performance difference between the designed scheme and IEEE802.11n standard is small, and the bit error rate can reach 10-7, which achieves the expected result.