共查询到20条相似文献,搜索用时 0 毫秒
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Tao Jiang Weidong Xiang Richardson P.C. Daiming Qu Guangxi Zhu 《Wireless Communications, IEEE Transactions on》2007,6(6):2017-2021
In this paper, we provide the design criteria of the nonlinear companding transforms for reduction in peak-to-average power ratio (PAPR) of multi-carrier modulation (MCM) signals, which can enable the original MCM signals to be transformed into the desirable distribution. As examples, some novel nonlinear companding transforms have been proposed to transform the amplitude or power of the original MCM signals into uniform distribution, which can effectively reduce the PAPR for different modulation formats and subcarrier sizes without any complexity increase and bandwidth expansion. It has been shown by computer simulations that the proposed schemes can significantly improve the performance of MCM systems including bit-error-rate and PAPR reduction. 相似文献
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一种降低OFDM系统PAPR的改进压扩方法 总被引:1,自引:1,他引:0
正交频分复用(OFDM)技术是一种多载波调制方式。作为第四代移动通信系统的核心技术,OFDM己成为当今高速无线通信领域的研究热点。正交频分复用(OFDM)系统存在高峰值平均功率比(PAPR)问题,这一问题会导致系统性能降低,为其实用化设置了障碍。文中研究了一种改进的降低PAPR的非线性压缩与扩展算法,可以得到更好的PAPR性能。该方法的特点在于采用一种计算复杂度较低的非线性压扩函数,同时融合了叠加训练序列方法的改进非线性压扩算法,从而有效地降低系统PAPR。理论研究和仿真结果表明,与传统方法相比,所提出的改进压缩与扩展方法可以在降低系统复杂度的同时得到更好的PAPR性能。 相似文献
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OFDM技术的应用越来越广泛,但是其发送信号功率的峰均功率比(PAPR)比较大是其主要的缺陷之一。本文提出了一个降低OFDM信号PAPR的有效灵活的技术。该方法是通过恰当的选择OFDM调制中各个子载波的时域脉冲波形。仿真结果表明该方法能够大大降低OFDM信号的PAPR值。该技术与现有的其他方法相比实现复杂度也更低。 相似文献
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Linear Companding Transform for the Reduction of Peak-to-Average Power Ratio of OFDM Signals 总被引:1,自引:0,他引:1
《Broadcasting, IEEE Transactions on》2009,55(1):155-160
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正交频分复用(OFDM)技术的一个缺点是信号的高峰值平均功率比(PAPR)大大降低了系统中线性功放的效率。本文提出一种新的基于Nyquist脉冲成形的PAPR抑制方法。这种方法基于选择适当的Nyquist脉冲波形集合对OFDM的各个子载波进行脉冲成形。分析论证了该方法的PAPR上限值和所用的脉冲成形波形集合。仿真结果表明该方法能有效降低任意子载波数目的OFDM信号的PAPR值,而且与已有方法相比应用更为简单。因此脉冲成形技术不仅能对传输信号进行频谱成形来提高系统的频带利用率,而且还可以减小信号的PAPR值。 相似文献
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PAPR Reduction of OFDM Signals Using Partial Transmit Sequences and Reed-Muller Codes 总被引:1,自引:0,他引:1
Houshou Chen Hsinying Liang 《Communications Letters, IEEE》2007,11(6):528-530
This letter proposes a modified PTS technique using binary Reed-Muller (RM) codes for error correction and PAPR control in BPSK OFDM systems. A RM code is divided into the direct sum of a correcting subcode for encoding information bits and a scrambling subcode for encoding PAPR bits. The transmitted signal of the resulting OFDM sequence is selected with minimum PAPR from a number of candidates which are codewords of a coset of the scrambling subcode. We consider the RM codes in natural and cyclic orderings. Numerical results show that RM codes in cyclic ordering achieve better performance in PAPR reduction than RM codes in natural ordering. 相似文献
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介绍了一种新颖的OFDM信号峰均比降低技术,不仅削去峰值信号,也削去谷值信号,从而最大程度上降低了信号的峰均比。矢量孔技术可以同时调整信号幅度和相位,使得信号矢量回避零点,信号谷值由此被削去。为了限制峰均比降低技术带来的带内和带外失真,该方法还进一步结合了闲置载波技术。仿真结果表明,经过该方法对QPSK调制的OFDM信号进行降低峰均比处理之后,信号峰均比从10.61dB降低到了7.03dB,EVM值保持为4.93%。该方法可以大幅度提高OFDM通信系统中功率放大器的效率和线性度。 相似文献
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PAPR Reduction of OFDM Signals Using Partial Transmit Sequences With Low Computational Complexity 总被引:4,自引:0,他引:4
Tao Jiang Weidong Xiang Richardson P.C. Jinhua Guo Guangxi Zhu 《Broadcasting, IEEE Transactions on》2007,53(3):719-724
Partial transmit sequences (PTS) is one of the attractive techniques to reduce the peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) system. As conventional PTS technique requires an exhaustive searching over all the combinations of the given phase factors, which results in the computational complexity increases exponentially with the number of the sub-blocks. In this paper, we aim to obtain the desirable PAPR reduction with the low computational complexity. Since the process of searching the optimal phase factors can be categorized as combinatorial optimization with some variables and constraints, we propose a novel scheme, which is based on a nonlinear optimization approach named as simulated annealing (SA), to search the optimal combination of phase factors with low complexity. To validate the analytical results, extensive simulations have been conducted, showing that the proposed schemes can achieve significant reduction in computational complexity while keeping good PAPR reduction. 相似文献
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In recent time orthogonal frequency division multiplexing (OFDM) has proved its mettle as a preferred choice for high speed transmission in wireless applications due its efficient mechanism to combat the inter symbol interference. However sudden high peaks in OFDM signal envelope lead to high peak to average power ratio (PAPR). Enhanced values of PAPR result into complex RF amplifier circuit with reduced efficiency. There are various methods available for PAPR reduction, out of them partial transmit sequence (PTS) is most effective proven choice for PAPR reduction. However PTS technique requires cumbersome searching of all possible phase factors to find optimal phase factor which produces lowest PAPR, the information regarding optimal phase set used at the transmitter need to be sent to the receiver as side information (SI) for decoding purpose, however transmitting SI requires additional transmission bandwidth thus reducing overall bandwidth efficiency. To reduce the exhaustive searching genetic algorithm (GA) could be used with PTS leading to GA-PTS system. In this paper a GA-PTS system is proposed which uses novel octagonal geometry for constellation extension purpose. This scheme does not require transmission of any side information for decoding purpose at receiver and at the same time GA-PTS system reduces the required number of searches. Simulations are presented to show that proposed scheme provides similar PAPR performance as conventional PTS but without need of SI transmission at reduced number of searches. 相似文献
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Ibraheem Zeyid T. Ahmed Kawakib K. Fazea Yousef Madi Mohammed Mohammed Fathey Ali Abdulrazzaq Qasem 《Wireless Personal Communications》2022,124(1):423-436
Wireless Personal Communications - This paper proposes an enhanced PAPR reduction technique which combines an enhanced PTS method with Mu-Law companding. The enhanced PTS method improves... 相似文献
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凭借很强的抗符号间干扰(ISI)和抗衰落能力,采用正交频分信道的OFDM技术的无线通信越来越受到人们的重视。但是作为一种多载波调制方式,OFDM技术同样存在着高峰均比(PAPR)的问题,高的PAPR会导致信号畸变,造成子信道间的相互干扰,从而影响OFDM的性能。针对此,重点介绍了OFDM系统中的PAPR比问题的概念,并对降低PAPR的主要算法进行了论述。 相似文献
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降低信号的峰均功率比(PAPR)是正交频分复用(OFDM)技术的一个关键问题。μ律压扩法作为降低PAPR的一个重要方法,其非线性的特点难于在硬件上实现。在传统的μ律压扩方法基础上,介绍了一种分段线性压扩方法,并对其效果进行仿真评估,并提出一种新的硬件实现方法,在降低复杂度上有良好的效果。 相似文献
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Byung Moo Lee Rui J. P. de Figueiredo Youngok Kim 《Wireless Personal Communications》2012,62(2):431-442
The high peak-to-average power ratio (PAPR) of time domain signals has been a major problem in orthogonal frequency division
multiplexing (OFDM) systems, and thus various PAPR reduction algorithms have been introduced. Partial transmit sequence (PTS)
is one of the most attractive solutions because of its good performance without distortion. However, it is considered as an
impractical solution for the realization of high-speed data transmission systems due to its high computational complexity.
In this paper, a novel PAPR reduction algorithm based on a tree-structured searching technique is proposed to reduce the PAPR
with low complexity. In the proposed scheme, the computational complexity of searching process is decreased by adjusting the
size of tree with two parameters, width and depth, while preserving good performance. The simulation results show that proposed
scheme provides similar performance with optimum case with remarkably reduced computational complexity. 相似文献
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In this paper, an adaptive-network-based fuzzy inference system (ANFIS) based scheme is analyzed and proposed for reducing the peak-to-average power ratio (PAPR) in multicarrier signals under additive white Gaussian noise and multipath fading (Raleigh) channel environment. This scheme involves training of ANFIS structure in time domain using Orthogonal Frequency Division Multiplexing signals with low PAPR, such as those obtained by approximate gradient project–null subcarrier switching (AGP–NCS) method. Once the ANFIS module is trained, the proposed scheme approximately offers similar reduction in PAPR as compared to AGP–NCS method, with significantly less convergence time and computational complexity. he results show that proposed approach is not only less complex but also maintains the data rate and bit error rate performance compared with other conventional schemes. 相似文献
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《Broadcasting, IEEE Transactions on》2009,55(3):679-685
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Xinchun Wu Jinxiang Wang Zhigang Mao Jianwei Zhang 《Circuits, Systems, and Signal Processing》2010,29(3):499-514
The interleaved partitioning partial transmit sequence (IP-PTS) scheme is an attractive technique for peak-to-average power
ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems. But the PAPR performance of IP-PTS is
inferior to that of the adjacent partitioning PTS (AP-PTS) scheme because the candidates generated in IP-PTS are not fully
independent. This paper analyzes the independence of candidates in IP-PTS in detail and finds the effective phase factor vectors.
In order to improve the PAPR performance of IP-PTS, a conjugate IP-PTS (C-IP-PTS) scheme is proposed. By performing the conjugate
operations on some sub-blocks, the number of candidates is increased. Because of the conjugate property of the discrete Fourier
transform (DFT), the additional inverse DFT can be avoided. By optimizing the conjugate sequence, the complexity can be further
lowered. Simulation results show that C-IP-PTS can obtain better PAPR performance compared with AP-PTS; moreover, the computational
complexity of C-IP-PTS is not high. 相似文献