LED nonlinearity mitigation techniques in optical wireless OFDM communication systems
LED nonlinearity mitigation techniques in optical wireless OFDM communication systems
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DOI：
10.1364/jocn.4.000865
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发表时间：
2012-11
期刊：
影响因子：
--
通讯作者：
R. Mesleh;H. Elgala;H. Haas
中科院分区：
文献类型：
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作者：
R. Mesleh;H. Elgala;H. Haas
发光二极管（LED）非线性对基于正交频分复用（OFDM）调制的光无线（OW）通信系统的性能有显着影响。在本文中，不同的技术来补偿诱导的非线性失真的介绍和分析。首先，单载波频分多址（SC-FDMA）提出了替代OFDM的OW系统。在SC-FDMA中，固有地解决了一些主要的OFDM问题，诸如高峰均功率比。结果表明，在一定的输入信号功率和调制阶数下，正交频分复用系统和SC-FDMA系统的性能是折衷的。其次，OW OFDM系统的硬，软，和Turbo信道编码技术被认为是。据报道，显着的性能增益可以通过信道编码实现。最后，提出了一种通过使用迭代信号限幅（ISC）和多个发射LED来减少信号限幅失真的新方法。ISC技术基于时域OFDM信号的迭代限幅和来自多LED发射器的传输。传输LED是同步的，彼此靠近，并放置在同一方向发光。因此，从每个LED到接收器光电二极管的通道路径增益相似。来自不同LED的接收信号在接收器处相干地相加。报告的结果表明，失真的影响被消除或显着减少的基础上所考虑的发射LED的数量。
Light emitting diode (LED) nonlinearities have a significant impact on the performance of optical wireless (OW) communication systems based on orthogonal frequency division multiplexing (OFDM) modulation. In this paper, different techniques to compensate for the induced nonlinearity distortions are presented and analyzed. First, single-carrier frequency division multiple access (SC-FDMA) is proposed instead of OFDM for OW systems. In SC-FDMA, some of the major OFDM problems such as high peak-to-average power ratio are inherently resolved. It is shown that the performance of OW OFDM systems and their counterpart SC-FDMA systems are traded off for certain input signal powers and modulation orders. Second, OW OFDM systems with hard, soft, and turbo channel coding techniques are considered. It is reported that significant performance gains can be achieved through channel coding. Finally, a novel method to reduce signal clipping distortion through the use of iterative signal clipping (ISC) and multiple transmit LEDs is proposed. The ISC technique is based on iterative clipping of the time domain OFDM signal and transmission from a multiple LED transmitter. Transmit LEDs are synchronized, located close to each other, and placed to emit light in the same direction. Hence, the channel path gains from each LED to the receiver photodiode are similar. The received signals from the different LEDs add coherently at the receiver. Reported results demonstrate that the effect of distortion is eliminated or significantly reduced based on the considered number of transmit LEDs.