Spectral precoding is a promising technique to suppress out-of-band emissions and comply with leakage constraints over adjacent frequency channels and with mask requirements on the unwanted emissions. However, spectral precoding may distort the original data vector, which is formally expressed as the error vector magnitude (EVM) between the precoded and original data vectors. Notably, EVM has a deleterious impact on the performance of multiple-input multiple-output orthogonal frequency division multiplexing-based systems. In this paper we propose a novel spectral precoding approach which constrains the EVM while complying with the mask requirements. We first formulate and solve the EVM-unconstrained mask-compliant spectral precoding problem, which serves as a springboard to the design of two EVM-constrained spectral precoding schemes. The first scheme takes into account a wideband EVM-constraint which limits the average in-band distortion. The second scheme takes into account frequency-selective EVM-constraints, and consequently, limits the signal distortion at the subcarrier level. Numerical examples illustrate that both proposed schemes outperform previously developed schemes in terms of important performance indicators such as block error rate and system-wide throughput while complying with spectral mask and EVM constraints.

中文翻译：

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受 EVM 约束且符合模板的 MIMO-OFDM 频谱预编码

频谱预编码是一种很有前途的技术，可以抑制带外发射并符合相邻频道的泄漏约束以及对无用发射的掩码要求。然而，频谱预编码可能会使原始数据向量失真，原始数据向量正式表示为预编码数据向量和原始数据向量之间的误差向量幅度 (EVM)。值得注意的是，EVM 对基于多输入多输出正交频分复用的系统的性能产生有害影响。在本文中，我们提出了一种新颖的频谱预编码方法，该方法在满足掩码要求的同时约束 EVM。我们首先制定并解决了 EVM 无约束掩码兼容频谱预编码问题，这是设计两个 EVM 约束频谱预编码方案的跳板。第一种方案考虑了限制平均带内失真的宽带 EVM 约束。第二种方案考虑了频率选择性 EVM 约束，因此限制了副载波级别的信号失真。数值示例表明，在遵守频谱掩码和 EVM 约束的同时，两种提议的方案在重要性能指标（例如误块率和系统范围吞吐量）方面都优于先前开发的方案。