Low-complexity frequency domain nonlinear compensation for OFDM based high-speed visible light communication systems with light emitting diodes.
Low-complexity frequency domain nonlinear compensation for OFDM based high-speed visible light communication systems with light emitting diodes.
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DOI：
10.1364/oe.25.003780
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发表时间：
2017-02
期刊：
影响因子：
3.8
通讯作者：
Guowu Zhang;Junwei Zhang;Xuezhi Hong;Sailing He
中科院分区：
文献类型：
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作者：
Guowu Zhang;Junwei Zhang;Xuezhi Hong;Sailing He
针对基于正交频分复用（OFDM）的可见光通信系统，提出了一种新的频域非线性补偿方法FD-NC。与传统的时域沃尔泰拉非线性补偿方法（TD-NC）相比，该方法在频域而非时域处理发光二极管（LED）的记忆非线性损伤，具有更低的计算复杂度。理论推导和实验研究所提出的方法在基于OFDM的VLC系统与四种类型的商业LED。实验结果表明，所提出的低复杂度的FD-NC方法具有适度的截断因子，实现了性能相媲美的TD-NC。实验证明了FD-NC方法在比特功率加载的OFDM VLC系统中的应用。在误码率为3.8 × 10-3的情况下，与线性均衡情况相比，FD-NC可使960 Mbps VLC系统的传输距离从0.7 m扩展到1.8 m;（B）在0.5 m~2 m的传输距离范围内，FD-NC可使系统容量提高18.7%~36.5%。复杂度分析表明，FD-NC所需的实值乘法次数（RNRM）与线性或非线性存储器长度无关。对于较大的非线性记忆长度或较小的截断因子，FD-NC比TD-NC实现的RNRM的降低变得更加深刻。
A novel frequency domain nonlinear compensation method, FD-NC, is proposed for orthogonal frequency division multiplexing (OFDM) based visible light communication (VLC) system. By tackling the memory nonlinear impairments from light emitting diodes (LEDs) in the frequency domain rather than in the time domain, the proposed method has much lower computational complexity than the conventional time domain Volterra nonlinear compensation method (TD-NC). Both theoretical derivation and experimental investigation of the proposed method in OFDM based VLC systems with four types of commercial LEDs are presented. The results of experiments show that the proposed low-complexity FD-NC method with a moderate truncation factor achieves a performance comparable to that of the TD-NC. The application of FD-NC method in the bit-power loading OFDM VLC system is also experimentally demonstrated. Compared with the linear equalization case, at a bit error rate (BER) of 3.8 × 10-3 (a), the transmission distance of a 960 Mbps VLC system can be extended from 0.7 m to 1.8 m by the FD-NC, and (b) the achievable system capacity can be enhanced by 18.7%~36.5% for transmission distance in the range of 0.5 m~2 m with the FD-NC. The complexity analysis shows that the required number of real-valued multiplications (RNRM) of the FD-NC is independent of linear or nonlinear memory length. The reduction of RNRM achieved by the FD-NC over the TD-NC becomes more profound for a larger nonlinear memory length or a smaller truncation factor.