Pilot-Assisted PAPR Reduction Technique for Optical OFDM Communication Systems
Pilot-Assisted PAPR Reduction Technique for Optical OFDM Communication Systems
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DOI：
10.1109/jlt.2014.2304493
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发表时间：
2014-04-01
影响因子：
4.7
通讯作者：
Stewart, Brian G.
中科院分区：
文献类型：
--
作者：
Popoola, Wasiu O.;Ghassemlooy, Zabih;Stewart, Brian G.
本文研究了导频信号在降低正交频分复用(Ofdm)强度调制的无线光通信系统的电峰均功率比(PAPR)中的作用。基于选择映射(SLM)算法选择导频信号的相位，而在接收端使用最大似然准则来估计导频信号。在建立可靠的通信链路所需的小于10(-3)的期望误码率时，导频辅助的光ofdm系统的误码率性能与基本光ofdm(没有导频和没有实施峰均比降低技术)的性能相同。导频辅助的PAPR降低技术使得高阶(M>；4)星座的PAPR比经典的SLM有更高的降低。对于基本的正交频分复用系统，在没有导频和没有实施峰均比降低技术的情况下，导频辅助的M-QAM光正交频分复用系统能够在M=的适度互补累积分布函数(CCDF)为10(-4)的情况下将电峰均比降低约2.5db。在不降低系统差错性能的情况下，在CCDF的较低值时可以更大程度地降低PAPR。在相同的CCDF为10(-4)的情况下，温和地对两端的时域信号进行限幅(在信号方差水平的25倍处)会导致PAPR降低约6.3分贝，但误差平台约为3×10(-5)。虽然通过信号限幅可以达到任何期望的电峰均功率比降低水平，但这将以系统的误码性能恶化为代价。
This paper investigates the use of a pilot signal in reducing the electrical peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) intensitymodulated optical wireless communication system. The phase of the pilot signal is chosen based on the selected mapping (SLM) algorithm while the maximum likelihood criterion is used to estimate the pilot signal at the receiver. Bit error rate (BER) performance of the pilot-assisted optical OFDM system is identical to that of the basic optical OFDM (with no pilot and no PAPR reduction technique implemented) at the desired BER of less than 10(-3) needed to establish a reliable communication link. The pilot- assisted PAPR reduction technique results in higher reduction in PAPR for high order (M > 4) constellations than the classical SLM. With respect to a basic OFDM system, with no pilot and no PAPR reduction technique implemented, a pilot- assisted M-QAM optical OFDM system is capable of reducing the electrical PAPR by over about 2.5 dB at a modest complementary cumulative distribution function (CCDF) point of 10(-4) for M = 64. Greater reductions in PAPR are possible at lower values of CCDF with no degradation to the system's error performance. Clipping the time domain signal at both ends mildly (at 25 times the signal variance level) results in a PAPR reduction of about 6.3 dB at the same CCDF of 10(-4) but with an error floor of about 3 x 10(-5). Although it is possible to attain any desired level of electrical PAPR reduction with signal clipping, this will be at a cost of deterioration in the systems's bit error performance.