共查询到18条相似文献,搜索用时 125 毫秒
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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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多输入多输出频分复用技术是将OFDM与MIMO技术相结合的无线通信系统,也具有OFDM系统存在的峰均比较高的问题。分析了MIMO-OFDM系统模型及PAPR问题,在次优PTS算法的基础上,提出了迭代限幅PTS联合算法。该算法先将MIMO-OFDM信号经过迭代PTS算法进行处理,然后再将其经过限幅处理进一步降低系统的PAPR。最后在自适应PTS算法的基础上进行了改进,仿真结果表明系统复杂度和PAPR性能有所降低,但可以通过调整门限来提高性能。 相似文献
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相较于传统正交频分复用(Orthogonal Frequency Division Multiplexing, OFDM)技术,滤波OFDM(Filtered OFDM, F-OFDM)技术具有子载波带宽灵活可变和抑制频谱带外泄露等优点,是面向未来无线通信系统的候选波形之一.但是在高动态通信场景下,时变信道中存在的多普勒频偏现象却依然会严重损害F-OFDM系统的性能.针对该问题,提出一种基于变换域的迭代消息传递检测(Message Passing Detection, MPD)算法.MPD算法基于稀疏因子图,通过在收发节点间进行迭代式的消息传递和状态更新,最终实现对多普勒频偏的抑制.此外,通过对检测过程中的干扰进行高斯等效,能够一定程度上降低迭代MPD检测算法的复杂度.进一步的,所提算法基于变换域的设计思路,能够充分利用时变多径信道在变换域的增强型稀疏性,以此有效减少MPD算法中收发节点间的连接支路数,进而降低检测算法的计算复杂度.基于F-OFDM系统的仿真结果表明,相较于传统的时频域MPD算法,所提基于变换域的迭代MPD算法在系统误码率和计算复杂度上均有更为优异的性能表现. 相似文献
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正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)信号具有较高的峰均功率比(Peak to Average Power Ratio,PAPR),不仅影响功率放大器(High Power Amplifier,HPA)的工作效率,而且HPA使得OFDM信号产生严重的非线性失真,导致系统的误比特率(Bite Error Rate,BER)增大.本文基于限幅和压缩感知(Compressive Sensing,CS)提出了改进的补偿算法,发送端采用限幅降低信号的PAPR,接收端首先采用改进的逆模型方式减小HPA引入的非线性失真,再采用CS抵消由限幅引入的信号失真.仿真表明,所提方法不仅明显降低了OFDM信号的PAPR,而且有效提高了系统的BER性能. 相似文献
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PTS与限幅结合降低OFDM峰均比的改进算法 总被引:2,自引:2,他引:0
提出了一种基于部分传输序列(PTS)算法和限幅算法相结合的改进算法来降低正交频分复用(OFDM)系统的峰均功率比(PAPR).该算法先利用PTS算法对OFDM信号进行处理从而选择出限幅噪声最小的一路OFDM信号,所得OFDM信号再利用限幅法进行处理.因此可有效改善OFDM信号经过限幅引起的限幅噪声,减小限幅对OFDM系统的影响.数据仿真验证了所提方法的有效性. 相似文献
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Yasir Amer Al-Jawhar Khairun N. Ramli Montadar Abas Taher Nor Shahida M. Shah Salama A. Mostafa Bashar Ahmed Khalaf 《ETRI Journal》2021,43(2):209-220
The filtered orthogonal frequency division multiplexing (F-OFDM) system has been recommended as a waveform candidate for fifth-generation (5G) communications. The suppression of out-of-band emission (OOBE) and asynchronous transmission are the distinctive features of the filtering-based waveform frameworks. Meanwhile, the high peak-to-average power ratio (PAPR) is still a challenge for the new waveform candidates. Partial transmit sequence (PTS) is an effective technique for mitigating the trend of high PAPR in multicarrier systems. In this study, the PTS technique is employed to reduce the high PAPR value of an F-OFDM system. Then, this system is compared with the OFDM system. In addition, the other related parameters such as frequency localization, bit error rate (BER), and computational complexity are evaluated and analyzed for both systems with and without PTS. The simulation results indicate that the F-OFDM based on PTS achieves higher levels of PAPR, BER, and OOBE performances compared with OFDM. Moreover, the BER performance of F-OFDM is uninfluenced by the use of the PTS technique. 相似文献
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针对正交频分复用(OFDM)可见光通信系统中存在高峰均功率比的问题,将预编码与迭代限幅滤波技术相结合应用于Hartley变换OFDM调制的可见光通信系统中,并对传统的采用FFT/IFFT限幅滤波的OFDM系统进行改进。根据建立的FHT的可见光OFDM系统模型,分别比较了不同方案下系统的频谱利用率、PAPR和误码率等性能,并分析了离散余弦变换和Hadamard矩阵预编码对PAPR的抑制作用以及FFT/IFFT、DCT/IDCT和FHT/IFHT三种不同变换方案的滤波性能。结果表明:FHT的可见光OFDM系统比FFT的OFDM系统的计算复杂度低、频谱利用率高;DCT预编码技术在克服系统PAPR及提升系统误码性能上更具优势;FHT/IFHT迭代限幅滤波的误码性能优于FFT/IFFT和DCT/IDCT。 相似文献
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在OFDM 系统中,限幅常用于抑制信号的峰平比,而限幅会引入额外的限幅噪声,以致干扰数据和导引符号,恶化传输性能.本文针对限幅OFDM系统,提出一种基于导引符号的限幅噪声消除算法.该算法在插入导引符号之前,滤除位于导引位置的限幅噪声,从而改善信道估计性能.在此基础上,本文还提出了利用迭代算法以进一步提高信道估计精确度.本文对所提出的限幅噪声消除算法及迭代算法进行了仿真验证,结果表明,新算法能够明显改善信道估计,优化传输性能. 相似文献
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In recent years, many peak-to-average power ratio (PAPR) reduction techniques have been proposed for orthogonal frequency division multiplexing (OFDM) signals. Among various techniques, the iterative clipping and filtering (ICAF) technique has been considered as a practical scheme, and widely used owing to its non-expansion of bandwidth, low computational complexity, and simplicity in implementation without receiver-side cooperation. However, the performance of conventional ICAF technique is degraded, because the same signals are iteratively clipped with a fixed clipping threshold (CT) in every clipping operation. In this paper, we analyze the performance of conventional ICAF technique, and then propose an adaptive ICAF scheme, which clips the signal with an adaptively modified CT in every clipping operation to achieve enhanced PAPR reduction of OFDM signals. Simulation results show that the proposed scheme significantly outperforms the conventional scheme, in PAPR reduction of OFDM signals at the same number of iterations. 相似文献
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一种降低OFDM信号PAPR的改进PTS方法 总被引:1,自引:0,他引:1
正交频分复用(OFDM)系统的一个主要缺点是信号的峰值功率与平均功率比(PAPR)很高。本文研究了利用信号扰码技术降低OFDM系统峰均比的一种典型算法:部分传输序列法(PTS),提出了一种将随机分割方法、交织分割方法与迭代移位搜索加权因子相结合的改进PTS算法。仿真结果表明,改进后的算法在改善PAPR性能和计算的复杂度之间取得了较好的折衷。 相似文献
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The orthogonal frequency division multiplex (OFDM) technique, which is used in the 4G communications, has a shortcoming of having a high peak to average power ratio (PAPR), and thus a lot of research has been conducted to reduce the PAPR in OFDM systems. The typical algorithms in this research area are the multi-time clipping algorithm, the \(\mu \)-law compression algorithm, SLM algorithm, PTS algorithm, and Golay complement sequence algorithm. It is found in this paper that the SLM and PTS algorithms have good performance in reducing the PAPR while having less information overhead than the Golay complement sequence algorithm, less distortion than the \({\mu }\)-law compression algorithm, and less BER than the clipping algorithm. Thus, a new PAPR reduction algorithm is proposed, which tries to intelligently apply both PTS and SLM algorithm, while utilizing their complementary advantages and avoiding their disadvantages. According to simulation results, the performance of the proposed algorithm has much better performance in reducing the PAPR than the SLM and PTS algorithms, with comparable computational complexity, BER performance, and information overhead. 相似文献
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基于随机分割的PTS改进算法研究 总被引:2,自引:1,他引:1
正交频分复用(OFDM)系统的一个主要缺点是信号的峰均功率比(PAPR)很高。提出了一种将随机分割方法与迭代移位搜索加权因子相结合的改进PTS算法。仿真结果表明,改进后的算法在改善PAPR性能和计算的复杂度之间取得了较好的折衷。 相似文献