Direct satellite uplink is severely constrained by limited link budgets, which hinder the exploitation of wideband resources, and ultimately limit the throughout. This paper presents a pilot-less coded modulation scheme based on sparse superposition coding (SSC) to enable efficient wideband usage in coverage-limited scenarios. This scheme leverages the structured Zadoff-Chu quasi-orthogonal (ZC-QO) dictionary to support scalable transmission. To address decoding complexity, the SSC transmitted signal embeds root index information via indicator sequences, allowing the receiver to restrict the decoding search space. In addition, a multi-codeword transmission framework with repetition and stop-feedback is developed, enabling reliable communication and better resource utilization. Simulation results show that the proposed scheme achieves throughput gains compared to a more conventional narrow-band multi-dimensional constellation-based approach.

翻译：直接卫星上行链路受限于有限的链路预算，这阻碍了宽带资源的利用，并最终限制了吞吐量。本文提出一种基于稀疏叠加编码的无导频编码调制方案，以在覆盖受限场景中实现高效宽带使用。该方案利用结构化的Zadoff-Chu准正交字典支持可扩展传输。为了解决译码复杂度，稀疏叠加编码传输信号通过指示序列嵌入根索引信息，使接收端能够限制译码搜索空间。此外，开发了具有重复和停止反馈的多码字传输框架，实现可靠通信和更好的资源利用率。仿真结果表明，与基于更传统窄带多维星座的方法相比，所提方案实现了吞吐量增益。