On the Optimization of Iterative Clipping and Filtering for PAPR Reduction in OFDM Systems
On the Optimization of Iterative Clipping and Filtering for PAPR Reduction in OFDM Systems
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DOI：
10.1109/access.2017.2711533
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发表时间：
2017-06
期刊：
影响因子：
3.9
通讯作者：
K. Anoh;Cagri Tanriover;B. Adebisi
中科院分区：
文献类型：
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作者：
K. Anoh;Cagri Tanriover;B. Adebisi
正交频分复用（OFDM）技术具有频谱利用率高的优点，但它受到峰均功率比（PAPR）问题的限制。可以使用迭代限幅和滤波（ICF）方案来降低PAPR，但是需要在不同的限幅迭代处使用固定的限幅阈值来迭代地限幅相同的信号。该方法保证了快速傅立叶变换（FFT）/逆FFT（IFFT）模块必须按照迭代的顺序被驱动多次以获得期望的PAPR阈值，这消耗了系统功率并扩展了处理时间。使用二阶锥规划，达到期望的PAPR阈值所需的迭代次数减少。这种优化的ICF（OICF），后来简化使用拉格朗日乘子（LM）。在本文中，我们将自适应限幅阈值应用于LM方案，以提高简化OICF（SOICF）的性能。我们的研究结果表明显着减少PAPR的问题相比，早期的SOICF计划，虽然有一些退化的误码率（BER）的性能，可以根据所选择的限幅阈值低于1.0 dB。此外，我们还说明了性能的结果和误差向量幅度（EVM）和PAPR之间的理论关系，限幅比（CR）和EVM之间的关系，最后EVM，PAPR，OFDM子载波数和CR之间的相互依赖关系。
Orthogonal frequency division multiplexing (OFDM) offers spectral efficiency advantage, however, it is limited by peak-to-average power (PAPR) problem. The PAPR can be reduced using iterative clipping and filtering (ICF) scheme but requires that the same signals are iteratively clipped with a fixed clipping threshold at different clipping iterations. This method warrants that fast-Fourier transform (FFT)/inverse FFT (IFFT) blocks must be driven in the order of iterations many times to attain a desired PAPR threshold which expends the system power and expands the processing time. Using a second-order cone program, the number of iterations required to attain the desired PAPR threshold was reduced. This optimized ICF (OICF) was later simplified using Lagrange multiplier (LM). In this paper, we apply an adaptive clipping threshold to the LM scheme to improve the performance of the simplified OICF (SOICF). Our results show significant reduction of the PAPR problem compared with the earlier SOICF scheme albeit with some degradation in the bit error ratio (BER) performance that can be under 1.0 dB depending on the chosen clipping threshold. In addition, we also illustrate the results of the performances and the theoretical relationships between the error vector magnitude (EVM) and PAPR, between clipping ratio (CR) and EVM, and lastly the inter-dependencies of EVM, PAPR, the number of OFDM subcarriers, and the CR.