In recent years, the rapid evolution of satellite communications play a pivotal role in addressing the ever-increasing demand for global connectivity, among which the Low Earth Orbit (LEO) satellites attract a great amount of attention due to their low latency and high data throughput capabilities. Based on this, we explore spatial modulation (SM) and space shift keying (SSK) designs as pivotal techniques to enhance spectral efficiency (SE) and bit-error rate (BER) performance in the LEO satellite-assisted multiple-input multiple-output (MIMO) systems. The various performance analysis of these designs are presented in this paper, revealing insightful findings and conclusions through analytical methods and Monte Carlo simulations with perfect and imperfect channel state information (CSI) estimation. The results provide a comprehensive analysis of the merits and trade-offs associated with the investigated schemes, particularly in terms of BER, computational complexity, and SE. This analysis underscores the potential of both schemes as viable candidates for future 6G LEO satellite-assisted wireless communication systems.

翻译：近年来，卫星通信的快速发展在满足日益增长的全球连接需求方面发挥着关键作用，其中低地球轨道卫星因其低延迟和高数据吞吐能力而备受关注。基于此，本文探讨了空间调制与空移键控设计作为提升低轨卫星辅助多输入多输出系统频谱效率和误码率性能的关键技术。本文通过解析方法与蒙特卡洛仿真，在理想及非理想信道状态信息估计条件下，对这些设计进行了多方面的性能分析，揭示了具有深刻见解的发现与结论。研究结果全面分析了所探讨方案的优势与权衡，特别是在误码率、计算复杂度和频谱效率方面的表现。该分析强调了这两种方案作为未来6G低轨卫星辅助无线通信系统可行候选技术的潜力。