When the channel state information is available, frequency-domain precoding is studied for rectangularly-pulsed orthogonal frequency-division multiplexing (OFDM) using cyclic prefix over dispersive channels to provide extremely compact signal spectrum, enhanced achievable data rate (ADR), and reduced peak-to-average power ratio (PAPR) jointly. With a precoding rate not larger than $1-2I/N$, a general precoder form is first developed for the transmitted $N$-subcarrier OFDM signal to provide extremely small baseband power spectral sidelobes decaying asymptotically as $f^{-2I-2}$ or faster, with $f$ being the frequency, and thus achieve high spectrum compactness while yielding reduced PAPR. Incorporating the channel response, a particular spectral precoder following the general form is then designed to maximize the ADR under a fixed transmitted power. When a small out-of-band power proportion is required to guarantee spectrum compactness, the proposed pre-equalized and spectrally-precoded OFDM system can provide much higher ADR per unit bandwidth than pre-equalized OFDM, spectrally-precoded OFDM, and nonprecoded OFDM. When the low-complexity receiver is mandatory, a systematically pre-equalized and spectrally precoded OFDM system is also developed to achieve enhanced ADR, extremely high spectrum compactness, and low-complexity receiver operation by trading transmission power on cancellation subcarriers.

中文翻译：

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预均衡和频谱预编码 OFDM

当信道状态信息可用时，研究频域预编码，用于矩形脉冲正交频分复用 (OFDM)，在色散信道上使用循环前缀，以提供极其紧凑的信号频谱、增强的可实现数据速率 (ADR) 和降低的峰值与平均功率比 (PAPR) 联合。预编码率不大于$1-2I/N$，首先开发了一个通用的预编码器形式，用于传输$N$- 子载波 OFDM 信号提供极小的基带功率谱旁瓣，其渐近衰减为$f^{-2I-2}$或更快，与$f$是频率，因此在降低 PAPR 的同时实现了高频谱紧凑性。结合信道响应，然后设计遵循一般形式的特定频谱预编码器以在固定发射功率下最大化 ADR。当需要较小的带外功率比例来保证频谱紧凑性时，所提出的预均衡和频谱预编码 OFDM 系统可以提供比预均衡 OFDM、频谱预编码 OFDM 和非预编码 OFDM 更高的单位带宽 ADR . 当低复杂度接收器是强制性的时，还开发了系统预均衡和频谱预编码的 OFDM 系统，以通过在抵消子载波上交换传输功率来实现增强的 ADR、极高的频谱紧凑性和低复杂度的接收器操作。