ABSTRACT In this paper, we investigate an enhanced form of spatial modulation, in the form of quadrature spatial modulation (QSM). The existing analytical error performance of QSM does not agree well with Monte Carlo simulation results in the low signal-to-noise ratio (SNR) region. Hence, the first contribution of the paper is to formulate a new analytical bound on error performance, which improves on the validation of simulation results at low SNRs. Secondly, a link adaptation technique for QSM is investigated in order to further improve its error performance. The proposed scheme is based on a selection technique between candidate transmission modes chosen to satisfy a target spectral efficiency, which employs optimal transmit antenna selection and modulation order selection, such as to minimize the average bit error probability (BEP). Euclidean distance-based antenna selection is employed to select the enumeration of transmit antennas for each transmission candidate, while the instantaneous BEP (IBEP) is employed to select the transmission candidate mode. Significant SNR gain over QSM is demonstrated. In order to reduce the computational complexity (CC) overhead of optimal transmit antenna selection, the third contribution is to investigate suboptimal low-complexity transmit antenna selection for the proposed scheme. Monte Carlo simulation results demonstrate a trade-off between the error performance and CC.

中文翻译：

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自适应正交空间调制

摘要 在本文中，我们研究了一种增强形式的空间调制，即正交空间调制 (QSM)。QSM 现有的解析误差性能与蒙特卡罗模拟结果在低信噪比 (SNR) 区域不一致。因此，本文的第一个贡献是制定了一个新的误差性能分析界限，这改进了低信噪比下仿真结果的验证。其次，研究了QSM的链路自适应技术，以进一步提高其错误性能。所提出的方案基于在为满足目标频谱效率而选择的候选传输模式之间的选择技术，其采用最佳发射天线选择和调制阶数选择，例如最小化平均误码率(BEP)。基于欧几里德距离的天线选择用于为每个传输候选选择发射天线的枚举，而瞬时BEP（IBEP）用于选择传输候选模式。证明了相对于 QSM 的显着 SNR 增益。为了减少最优发射天线选择的计算复杂度（CC）开销，第三个贡献是研究所提出方案的次优低复杂度发射天线选择。Monte Carlo 模拟结果证明了误差性能和 CC 之间的权衡。为了减少最优发射天线选择的计算复杂度（CC）开销，第三个贡献是研究所提出方案的次优低复杂度发射天线选择。Monte Carlo 模拟结果证明了误差性能和 CC 之间的权衡。为了减少最优发射天线选择的计算复杂度（CC）开销，第三个贡献是研究所提出方案的次优低复杂度发射天线选择。Monte Carlo 模拟结果证明了误差性能和 CC 之间的权衡。