Next-generation wireless communication systems impose much stricter requirements for transmission rate, latency, and reliability. The peak data rate of 6G networks should be no less than 1 Tb/s, which is comparable to existing long-haul optical transport networks. It is believed that using long error-correcting codes (ECC) with soft-decision decoding (SDD) is not feasible in this case due to the resulting high power consumption. On the other hand, ECC with hard-decision decoding (HDD) suffers from significant performance degradation. In this paper, we consider a concatenated solution consisting of an outer long HDD code and an inner short SDD code. The latter code is a crucial component of the system and the focus of our research. Due to its short length, the code cannot correct all errors, but it is designed to minimize the number of errors. Such codes are known as error-reducing codes. We investigate the error-reducing properties of superposition codes. Initially, we explore sparse regression codes (SPARCs) with Gaussian signals. This approach outperforms error-reducing binary LDPC codes optimized by Barakatain, et al. (2018) in terms of performance but faces limitations in practical applicability due to high implementation complexity. Subsequently, we propose an LDPC-based superposition code scheme with low-complexity soft successive interference cancellation (SIC) decoding. This scheme demonstrates comparable performance to SPARCs while maintaining manageable complexity. Numerical results were obtained for inner codes with an overhead (OH) of 8.24% within a concatenated scheme (15% OH) with an outer hard-decision decoded staircase code (6.25% OH).

翻译：下一代无线通信系统对传输速率、时延和可靠性提出了更为严苛的要求。6G网络的峰值数据速率应不低于1 Tb/s，这与现有长距离光传输网络的水平相当。普遍认为，在此场景下使用基于软判决译码（SDD）的长纠错码（ECC）因功耗过高而不可行。另一方面，采用硬判决译码（HDD）的ECC则存在显著的性能损失。本文研究了一种由外部长HDD码和内部短SDD码构成的级联方案。其中内部短SDD码是系统的关键组件，也是本研究的核心。由于码长较短，该码无法纠正所有错误，但其设计目标是最小化错误数量，此类码被称为减错码。我们研究了叠加码的减错特性。首先，探索了采用高斯信号的稀疏回归码（SPARC）。该方案在性能上优于Barakatain等人（2018年）优化的减错二元LDPC码，但因实现复杂度高而面临实际应用限制。随后，我们提出了一种基于LDPC的叠加码方案，采用低复杂度软连续干扰消除（SIC）译码。该方案在保持可管理复杂度的同时，展现出与SPARC相当的性能。数值实验针对级联方案（总开销15%）中开销为8.24%的内部码开展，其中外部采用硬判决译码的阶梯码（开销6.25%）。