The proliferation of ubiquitous computing applications created a multi-dimensional optimization problem that includes several conflicting variables such as spectral efficiency, complexity, power consumption, delay, and error probability. To relax the problem and provide efficient solutions, it was necessary to augment the currently overutilized radio spectrum with new frequency bands such as the optical spectrum, which can be used to off-load some of the traffic of certain applications. Therefore, this paper presents an efficient system design that uses amplitude-coherent (AC) detection to reduce the complexity of optical wireless communication systems (OWC), improve its reliability and spectral efficiency. More specifically, we use amplitude shift keying with orthogonal frequency division multiplexing (OFDM) at the transmitter, and AC detection at the receiver. The complexity reduction is achieved by using a low complexity detector, channel estimator, and peak-to-average power ratio (PAPR) reduction scheme. The spectral efficiency is achieved by using real data symbols with discrete cosine transform (DCT), which requires a subcarrier spacing that is 50% of the discrete Fourier transform (DFT), and does not require Hermitian symmetry to generate real-valued OFDM signals. Moreover, the derived channel estimator is blind, and the PAPR reduction scheme does not require a feedback overhead between the transmitter and receiver.

中文翻译：

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光学无线通信的幅度相干检测：机遇与局限

无处不在的计算应用程序的激增创造了一个多维优化问题，其中包括几个相互冲突的变量，例如频谱效率，复杂性，功耗，延迟和错误概率。为了缓解该问题并提供有效的解决方案，有必要使用诸如频谱之类的新频带来扩展当前过度使用的无线电频谱，这些频带可用于减轻某些应用程序的流量。因此，本文提出了一种有效的系统设计，该系统使用幅度相干（AC）检测来降低光无线通信系统（OWC）的复杂性，提高其可靠性和频谱效率。更具体地说，我们在发射机处使用幅度移位键控和正交频分复用（OFDM），接收器的交流检测。通过使用低复杂度检测器，信道估计器和峰均功率比（PAPR）降低方案，可以降低复杂度。频谱效率是通过使用具有离散余弦变换（DCT）的实际数据符号实现的，该离散余弦变换（DCT）所需的子载波间隔为离散傅里叶变换（DFT）的50％，并且不需要厄米对称性即可生成实值OFDM信号。而且，导出的信道估计器是盲的，并且PAPR减少方案不需要发射机和接收机之间的反馈开销。频谱效率是通过使用具有离散余弦变换（DCT）的实际数据符号实现的，该离散余弦变换（DCT）所需的子载波间隔为离散傅里叶变换（DFT）的50％，并且不需要厄米对称性即可生成实值OFDM信号。而且，导出的信道估计器是盲的，并且PAPR减少方案不需要发射机和接收机之间的反馈开销。频谱效率是通过使用具有离散余弦变换（DCT）的实际数据符号实现的，该离散余弦变换（DCT）所需的子载波间隔为离散傅里叶变换（DFT）的50％，并且不需要厄米对称性即可生成实值OFDM信号。而且，导出的信道估计器是盲的，并且PAPR减少方案不需要发射机和接收机之间的反馈开销。