降低可见光通信不均匀限幅正交频分复用系统非线性限幅失真的功率分配方法

发布时间：2018-05-05 23:39

本文选题：光通信 + 可见光通信　；参考：《光学学报》2014年07期

【摘要】：针对可见光通信中不均匀限幅光正交频分复用(ACO-OFDM)系统发光二极管(LED)非线性限幅失真严重的问题,提出了一种降低LED非线性限幅失真的最优功率分配方法。基于原信号直接叠加非线性限幅失真成分的限幅处理模型,分析了ACO-OFDM系统中的LED非线性限幅失真;利用有效信噪比来衡量限幅失真,将限幅失真转化为有效信噪比分析;基于有效信噪比最优的原则给出了光功率约束下降低限幅失真的最优偏置信号和ACO-OFDM信号功率分配。仿真结果表明,当信道的信噪比较低时,信道噪声起主导作用;当信道的信噪比较高时,限幅失真起主导作用。在光功率约束下若不考虑偏置信号的影响而直接取其值为LED最小输出功率限制,则系统误码率(BER)在信道信噪比大于40dB的情况下也始终大于10-2,而采用最优功率分配时可以保证系统具有较好的误码率性能,当光功率约束为200mW和250mW时,分别需要24dB和27dB的信道信噪比即可使得系统的误码率低于10-3。
[Abstract]:In order to solve the problem of serious nonlinear limiting distortion of light-emitting diode (LED) in non-uniform limiting optical orthogonal frequency division multiplexing (ACO-OFDM) system in visible light communication, an optimal power allocation method is proposed to reduce the nonlinear limiting distortion of LED. Based on the limiting processing model of the original signal directly superimposing the nonlinear limiting distortion component, the LED nonlinear limiting distortion in the ACO-OFDM system is analyzed, and the effective SNR is used to measure the limiting distortion and transform the limiting distortion into the effective SNR analysis. Based on the principle of optimal effective signal-to-noise ratio (SNR), the optimal power allocation of offset signal and ACO-OFDM signal for reducing limiting distortion under optical power constraints is presented. The simulation results show that the channel noise plays a dominant role when the SNR of the channel is low and the amplitude limiting distortion plays the leading role when the SNR of the channel is high. In the case of optical power constraints, the minimum output power limit of LED is chosen directly without considering the influence of the bias signal. The BER (bit error rate) of the system is always greater than 10 ~ (-2) when the channel SNR is greater than 40dB, and the optimal power allocation can ensure that the system has better BER performance. When the optical power is constrained by 200mW and 250mW, the BER performance of the system can be guaranteed when the optical power constraint is 200mW and 250mW. The channel SNR of 24dB and 27dB are required to make the BER of the system lower than 10-3.
【作者单位】：国家数字交换系统工程技术研究中心;东南大学移动通信国家重点实验室;
【基金】：国家863计划(2013AA013603) 东南大学移动通信国家重点实验室开放基金(2013D09)
【分类号】：TN929.1

【参考文献】