共查询到20条相似文献,搜索用时 15 毫秒
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Seog Geun Kang 《ETRI Journal》2006,28(2):235-238
In this letter, a block code that minimizes the peak‐to‐average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals is proposed. It is shown that peak envelope power is invariant to cyclic shift and codeword inversion. The systematic encoding rule for the proposed code is composed of searching for a seed codeword, shifting the register elements, and determining codeword inversion. This eliminates the look‐up table for one‐to‐one correspondence between the source and the coded data. Computer simulation confirms that OFDM systems with the proposed code always have the minimum PAPR. 相似文献
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为降低广义频分复用(GFDM)系统的峰均功率比(PAPR)、实现复杂度,提出了基于T变换和选择性映射(SLM)的TSLM算法,该算法的设计思想是利用SLM算法增加GFDM时域备选信号的数量以降低其PAPR,利用T变换实现串联的沃尔什-哈达玛变换和离散傅里叶反变换以降低GFDM系统的复杂度。为进一步降低GFDM系统的PAPR,提出了将TSLM算法和转换向量(CV)相结合的TCSLM算法,利用CV向量进一步增加GFDM时域备选信号的数量。结果表明,在子载波数为64、子符号数为3、相位序列数为2时,与SLM算法相比,TSLM算法和TCSLM算法的实现复杂度分别降低约21.9%和60.9%;在互补累计分布函数(CCDF)为10?3时,TSLM算法和TCSLM算法的PAPR分别降低约0.6 dB和1 dB;在误比特率为10?3时TSLM算法和TCSLM算法的误码性能均改善约2 dB。 相似文献
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针对光OFDM系统存在高峰均功率比(PAPR),提出了一种基于离散哈特利变换(DHT)的选择映射抑制算法。采用快速哈特利逆变换(IFHT)代替传统的快速傅立叶逆变换(IFFT)和Hermi t i an对称算法,并结合非对称限幅法产生满足光OFDM系统要求的正、实值信号送入光纤信道。 相似文献
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一种基于OPTS的降低OFDM峰均比的低复杂度算法 总被引:1,自引:0,他引:1
正交频分技术最主要缺点之一就是传输信号的高峰均值功率比,部分传输序列法是解决高峰均值功率比的最有效方法之一。虽然最优部分传输序列方法性能很好,但其计算复杂度非常大,搜索复杂度随着子块数指数增加,这样降低搜索复杂度显得尤为重要。本文改进TOPTS搜索过程中计算时域矢量的计算方法,使其计算复杂度大大降低,但系统性能不受影响。 相似文献
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正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)系统中,峰均功率比(Peak to AveragePower Ratio,PAPR)过高会导致收发器的非线性失真,严重影响系统的性能。传统的部分传输序列(Partial TransmitSequence,PTS)算法能够有效地降低PAPR,然而其计算复杂度随着分块数目增长呈指数增加。在研究PTS的基础上提出了双重迭代PTS算法,该算法利用增加迭代次数,并且每次迭代时选择不同的相位旋转因子集合来优化OFDM系统的峰均比性能。该算法在峰均比性能上优于常规OFDM系统以及普通迭代PTS算法,在降低峰均比性能和计算复杂度之间取得了较好的折衷。 相似文献
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滤波器组多载波(FBMC)是第五代蜂窝网络无线接入技术重点考虑的对象之一,然而其存在较高的峰均功率比(PAPR).通过分析FBMC-OQAM信号的重叠特性和信号功率分布特点,将传统选择性映射(SLM)方法加以改进,提出了一种比色散选择性映射(DSLM)方法更优的低复杂度色散选择性映射(LD-SLM)方法.LD-SLM方法用备选旋转矢量将当前数据块信号旋转,通过计算在当前信号周期[T,3T]区间内信号的PAPR来选取最优旋转矢量,并更新当前数据块信号,接着对下一个数据块信号进行同样的优化,直至所有的数据块都被优化.通过比较算法复杂度可知,LD-SLM算法相比DSLM算法降低了50%,仿真实验表明LD-SLM方法能有效降低FBMC-OQAM系统的PAPR. 相似文献
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Mehdi Hosseinzadeh Aghdam Abbas Ali Sharifi 《International Journal of Communication Systems》2021,34(1):e4648
The high peak‐to‐average power ratio (PAPR) is the main challenge of orthogonal frequency division multiplexing (OFDM) systems. Partial transmit sequence (PTS) is a useful approach to diminish the PAPR. Although the PTS approach significantly decreases the PAPR, it requires to explore all possible sequences of phase weighting factors. Hence, the computational cost exponentially increases with the number of divided subblocks. This paper proposes a novel PTS technique based on ant colony optimization (ACO) to diminish the high PAPR and computational cost of OFDM systems. By the new representation of phase factors as a graph, the improved ACO algorithm is combined with the PTS method to explore the optimal compound of the phase rotation factors. Simulation results represent that the proposed ACO‐based PTS approach significantly reduces the PAPR and improves the computational cost at the same time. A comparative analysis of the other meta‐heuristics shows that the ACO‐PTS approach outperforms the genetic algorithm, particle swarm optimization, and gray wolf optimization in terms of reducing PAPR. 相似文献
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Amnart Boonkajay Fumiyuki Adachi 《Wireless Communications and Mobile Computing》2016,16(16):2509-2522
Single‐carrier transmission with frequency‐domain equalization (SC‐FDE) is widely known as a promising transmission technique providing low error probability with low peak‐to‐average power ratio (PAPR) of transmit signal. However, the low‐PAPR property of SC‐FDE cannot be maintained if multi‐level data modulation is introduced. The low‐PAPR property of SC‐FDE can be maintained by applying transmit filtering with roll‐off factor at the expense of spectrum efficiency. In this paper, we propose two types of selected mapping (SLM) to reduce the PAPR of SC‐FDE transmit signal. The first SLM technique is conducted in the frequency domain, where the phase rotation is applied to subcarriers similar to the SLM technique for orthogonal frequency division multiplexing transmission. The second SLM technique is conducted in the time domain, where the phase rotation is applied directly to data‐modulated symbol sequence. Computer simulation confirms that both SLM techniques are able to reduce the PAPR of SC‐FDE signal without significant degradation of bit‐error rate performance and spectrum efficiency. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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本文针对OFDM系统中高峰均比问题,在基于正交映射降低峰平比的方法上提出了一种改进方案——随机分组正交映射(Random Group Design SLM),即在SLM前加入了对信号随机分组处理,再选择峰均比最小的一路信号作为输出,本文并对这种方法进行了多种条件下的系统仿真,实验结果表明这种方法在改善OFDM传输信号峰平比上,比SLM方法有明显的改善。 相似文献
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针对OFDM技术具有较高的峰均功率比(peak to average power ration,PAPR)这一主要缺点,提出一种控制OFDM载波信号衍生频谱的迭代算法,在降低系统高峰均功率比的同时,也降低系统的误码率.利用该算法对数据序列长度为64的OFDM信号进行仿真验证,随着迭代次数的增加,衍生频谱系数增大,系统平均功率增加,OFDM信号的峰值功率比得到一定的降低. 相似文献
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针对正交频分复用系统中的信号峰值平均功率比问题,提出了一种基于时域采样点幅度筛选的低复杂度部分传输序列算法。算法通过设置信号经过逆向傅里叶变换后时域采样点的幅度之和为判别函数,并设置适当的幅度门限,筛选出幅度大于门限的信号采样点集合,利用该集合来搜索信号峰均比抑制相位因子,从而降低算法复杂度。仿真表明,与传统峰均比抑制算法相比,改进算法在保持峰均比抑制性能的同时降低了算法复杂度。 相似文献
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Xiaofan He Tao Jiang Guangxi Zhu 《Wireless Communications and Mobile Computing》2011,11(10):1406-1414
In this paper, we first propose a simplified tone reservation (STR) method with low computational complexity which is based on the Fourier series expansion. Then, we analyze how to combine the STR method with the cross antenna rotation and inversion method to reduce the peak‐to‐average power ratio (PAPR) for multi‐input multi‐output orthogonal frequency division multiplexing (MIMO‐OFDM) system. To validate the analytical results, extensive simulations are conducted and the numerical results show the efficiency of the proposed schemes including the PAPR reduction and low computational complexity for MIMO‐OFDM system. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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OFDM技术具有很高峰平功率比(PAPR),这是其实用化的一个瓶颈。针对这一问题,构造了一个新的压扩函数来降低OFDM信号的峰平功率比,通过计算机仿真表明,它不但可以大幅度降低OFDM信号的PAPR,而且,还可以通过适当的选择压扩系数得到一定的系统增益。 相似文献
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Xinchun Wu Jinxiang Wang Bin Zhou Zhigang Mao Zhiqiang Gao 《International Journal of Communication Systems》2011,24(6):776-788
This paper proposes four companding transforms to reduce the peak‐to‐average power ratio in orthogonal frequency division multiplexing systems. The four companding transforms are obtained by transforming signal statistics into four trigonal distributions. Computer simulations show that the proposed schemes can effectively improve the PAPR performance and bit error rate performance of OFDM systems. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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The high peak‐to‐average power is one of the main drawbacks in OFDM systems. This letter proposes a partial shift mapping (PSM) method for peak power reduction in OFDM systems. By utilizing the properties of the discrete Fourier transform, the proposed method generates a set of candidate signals without additional complex multiplication and selects the one with minimum peak power for transmission. Analyses and simulations confirm that the PSM method achieves satisfactory peak power reduction performance and low complexity compared with other kindred methods, for example, selected mapping and partial transmit sequences. 相似文献
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