A Novel Peak-to-Average Power Ratio Reduction Scheme via Tone Reservation in OFDM Systems

In this paper, a novel signal-to-clipping noise ratio and least squares approximation tone reservation scheme(SCR-LSA TR) is proposed to reduce the peak-to-average power ratio for orthogonal frequency division multiplexing systems. During the SCR procedure, only the element with the maximal amplitude is picked for processing, which not only decreases the algorithm complexity, but also helps to overcome the BER deterioration. With the LSA method, the amplitude of the peak-cancelling signals can approximate to that of the original clipping noise as much as possible. Through the combination of the optimization factor in the LSA method, the classic SCR method can achieve better PAPR reduction with faster convergence. Simulation results show that the proposed SCR-LSA TR scheme has less in-band distortion and smaller out-of-band spectral radiation. The BER of the proposed scheme shows a better performance especially under the 16-QAM over the additive white Gaussian noise channel.

PSO-DBNet for Peak-to-Average Power Ratio Reduction Using Deep Belief Network

Data transmission through a wireless network has faced various signal problems in the past decades.The orthogonal frequency division multiplexing(OFDM)technique is widely accepted in multiple data transfer patterns at various frequency bands.A recent wireless communication network uses OFDM in longterm evolution(LTE)and 5G,among others.The main problem faced by 5G wireless OFDM is distortion of transmission signals in the network.This transmission loss is called peak-to-average power ratio(PAPR).This wireless signal distortion can be reduced using various techniques.This study uses machine learning-based algorithm to solve the problem of PAPR in 5G wireless communication.Partial transmit sequence(PTS)helps in the fast transfer of data in wireless LTE.PTS is merged with deep belief neural network(DBNet)for the efficient processing of signals in wireless 5G networks.Result indicates that the proposed system outperforms other existing techniques.Therefore,PAPR reduction in OFDM by DBNet is optimized with the help of an evolutionary algorithm called particle swarm optimization.Hence,the specified design supports in improving the proposed PAPR reduction architecture.

A PHASE SCRAMBLING SCHEME FOR SUPPRESSION OF PEAK TO AVERAGE POWER RATIO FOR OFDM

The complex-valued modulating vectors for the subcarriers consist of two kinds of components: One is the information-bearing components superposed with pseudo-randomized phases and the other is the suppression components with specified scrambling phases. The pseudo randomized phases are generated according to the predefined polynomial and mapping function whereas the scrambling phases are from a gradient algorithm. The simulation results verify the rationality and validity of the phase scrambling.

A correlation OPTS algorithm for reducing peak to average power ratio of FBMC-OQAM systems

A correlation overlapping partial transmit sequence(C-OPTS) algorithm is proposed to solve the issue of high complexity of overlapping partial transmit sequence(OPTS) algorithm in suppressing the peak to average power ratio(PAPR) of filter bank multicarrier-offset quadrature amplitude modulation(FBMC-OQAM) signals.The V subblocks in partial transmit sequence(PTS) are regrouped into U combinations according to the correlation coefficient p,and overlapping subblocks are allowed between adjacent groups.The search starts from the first group and sets the phase factors of the subsequent groups to 1.When the phase factors of the non-overlapping subblocks in the first group are determined,the subsequent groups are searched in turn to determine their respective phase factors.Starting from the second data block,the data overlapped with it should be taken into account when determining its optimal phase factor vector.Theoretical analysis and simulation results indicate that compared with the OPTS algorithm,the proposed algorithm can significantly reduce the computational complexity at the cost of slight deterioration of PAPR performance.Meanwhile,compared with the even-odd iterative double-layers OPTS(ID-OPTS) algorithm,it can further reduce the complexity and obtain a better PAPR suppression effect.

Reducing Peak-to-Average Power Ratio of a Turbo Coded OFDM

Peak to Average Power Ratio (PAPR) is defined as the instantaneous power (maximum value) to the average power ratio. PAPR is considered to be a major problem in OFDM systems. This problem can cause radical unexpected behavior of the signal fluctuation. This fluctuation is constituted by a large number of power states. The enormous number of these states leads to an additional complexity of ADCs and DACs. This research addresses the previous problem in OFDM systems utilizing Turbo Codes. μLaCP technique is employed for the purpose of decreasing PAPR. Moreover, our OFDM system was simulated in the presence of an AWGN channel with four types of codes (without the presence of ADCs and DACs). These were constituted of PCCC (typical and new), SCCC, and Convolutional Codes. Our Turbo Coded OFDM exhibited unchanged BER performance before and after the use of μLaCP technique. This was accomplished by modifying our previous PAPR reduction technique without sacrificing greatly its attributes.

Joint Optimization of Peak-to-Average Power Ratio and Spectral Leakage in 5G Multicarrier Waveforms

High peak-to-average-power ratio(PAPR) and spectral leakage are two main drawbacks of multicarrier systems, such as in orthogonal frequency division multiplexing(OFDM), in future 5G wireless communications. For generating optimized wave forms for 5G communications, this paper proposes an iterative scheme combining time-domain N-continuous OFDM(TD-NC-OFDM) and serial peak cancellation(SPC). Based on the theory of projection onto convex sets(POCS), the effectiveness of the proposed scheme is proved, and the optimized time-frequency domain multicarrier waveforms are analyzed in terms of a balanced tradeoff between out-of-band spectral leakage and PAPR. Both theoretical analysis and simulation results show that the proposed scheme can jointly optimize both the PAPR and out-ofband radiation, with moderate computational complexity.

Simulation on Peak-to-Average Power Ratio for Orthogonal Frequency Division Multiplexing

Clipping is a simple and convenient PAPR （peak-to-average power ratio） reduction method for high speed OFDM （orthogonal frequency division multiplexing） communication system. In this paper, we propose a new PAPR reduction method for Wireless-MAN（metropolitan area network）-OFDM system based on IEEE 802.16, which is over-sampling clipping arithmetic. Simulation and performance of the over-samples clipping＇s PAPR reduction capability, BER effect is given. The simulation indicates that the PAPR of at least 99.9% OFDM symbol is below 6dB after 2 Nyquist rate clipping, and the performance of BER has 1dB SNR（signal noise ratio） loss. The results prove that this method has better capacity to reducing PAPR. So it can be well used in WMAN-OFDM system.

A Low Complexity Linear Moving Average Filtering Technique for PAR Reduction in OFDM Systems

In this paper, a linear moving average recursive filtering technique is proposed to reduce the peak-to-average power ratio (PAR) of orthogonal frequency division multiplexing (OFDM) signals. The proposed low complexity technique is analyzed in an oversampled OFDM system and a simple distribution approximation of the oversampled and linearly filtered OFDM signals is also proposed. Corresponding time domain linear equalizers are developed to recover originally transmitted data symbols. Through extensive computer simulations, effects of the new filtering technique on the oversampled OFDM peak-to-average power ratio (PAR), power spectral density (PSD) and corresponding linear equalizers on the frequency selective Rayleigh fading channel transmission symbol-error-rate (SER) performance are investigated. The newly proposed recursive filtering scheme results in attractive PAR reduction, requires no extra fast Fourier transform/inverse fast Fourier transform (FFT/IFFT) operations, refrains from transmitting any side information, and reduces out-of-band radiation. Also, corresponding linear receivers are shown to perform very close to their frequency domain counterparts.

Inter-antenna and subblock shifting and inversion for peak-to-average power ratio reduction in MIMO-OFDM systems

In this article, an inter-antenna inter-subblock shifting and inversion （IASSI） scheme is proposed to reduce the peak-to-average power ratio （PAPR） in multi-input multioutput orthogonal frequency division multiplexing （MIMO- OFDM） systems. It exploits multiple antennas and subblocks to provide additional degrees of freedom to benefit the system. To reduce the implementation complexity of the proposed scheme, two simple suboptimal schemes are further presented based on the minimum current maximum criterion; one adopts sequential search and the other employs random binary grouping. The simulation results exhibit the effectiveness of these proposed schemes.

降低基于PSWF的非正弦调制信号PAR方法

针对基于椭圆球面波的非正弦调制信号峰均功率比大的问题,提出了降低峰均功率比方法。该方法根据基于椭圆球面波的非正弦调制符号时域特性,通过选择峰均功率比小于期望值的调制符号进行传输,从而达到降低调制信号峰均功率比的目的。理论分析和仿真结果表明,该方法不仅有效降低了调制信号的峰均功率比,而且不会降低通信系统的误码性能,也不会导致调制信号功率谱展宽和功率谱集中度变差。

ON THE PAR REDUCTION OF MB-OFDM ULTRA-WIDEBAND SIGNALS

The Peak to Average power Ratio (PAR) of a Multi-Band Orthogonal Frequency-Division Multiplexing (MB-OFDM) Ultra-Wide Band (UWB) signals can be substantially larger than that of single carrier or carrier-less ultra-wideband signals. In this letter, a novel PAR reduction scheme for the MB-OFDM UWB system based on spreading and interleaving is proposed. By spreading the coded bits over each subcarrier in corresponding band and interleaving the spread symbols across all bands, the PAR statistics of the MB-OFDM signals can be improved and the PAR is reduced obviously. In the PAR reduction scheme, there is no loss in transmission data rate or Bit Error Rate (BER) performance decreasing. Since the spreading and interleaving operation are implemented by unitary Hadamard sequences and used for an approach to provide the robustness of the UWB system to narrowband interference, there is no additional implementation burden. Simulation results show that the investigated scheme gives the PAR reduction of 3dB compared with that of the original MB-OFDM signals.

A Method for Improving Power Distribution Characteristics of Space Time Block Codes

Improving power distribution characteristics of space time block codes(STBCs),namely peak to average power ratio(PAPR),average to minimum power ratio(Ave/min),and probability of transmitting"zero"by antenna,makes easier their practical implementation.To this end,this study proposes to multiply full diversity STB C with a non-singular matrix in multiple input multiple output(MIMO)or multiple input single output(MISO)systems with linear or maximum likelihood(ML)receivers.It is proved that the obtained code achieves full diversity and the order of detection complexity does not change.The proposed method is applied to different types of STBCs.The bit error rate(BER)and power distribution characteristics of the new codes demonstrate the superiority of the introduced method.Further,lower and upper bounds on the BER of the obtained STBCs are derived for all receivers.The proposed method provides trade-off among PAPR,spectral efficiency,energy efficiency,and BER.

基于低PAR的机载雷达自适应发射抗噪声卷积干扰方法

鉴于新样式的噪声卷积灵巧干扰对机载雷达性能带来了愈加严重的影响,提出一种基于低峰均比(PAR)的机载雷达自适应发射抗噪声卷积灵巧干扰方法.该方法首先针对实际中灵巧干扰特性未知的情况,通过预先发射高重频脉冲串获取清晰区干扰样本,并利用正交匹配追踪(OMP)技术估计干扰角度;然后在此基础上利用低PAR约束优化自适应发射波束,使其在干扰机方向形成低增益凹口,以避免雷达发射信号被干扰机截获;最后在自适应发射基础上,对接收回波数据进行降维空时自适应处理(STAP).仿真结果表明,该方法形成的自适应发射波束在干扰机方向的凹口深度比传统方法深约8 dB,且运算量更低,显著降低了机载雷达发射信号被干扰机侦收的概率,有效提高了机载雷达抗干扰性能.

基于需求响应的家庭负荷优化调度算法研究

为提升电力需求侧负荷需求响应能力,降低家庭用户的用电成本和电网日负荷曲线峰谷差,提出一种基于改进多目标粒子群算法的家庭负荷优化调度策略。首先,分析家庭负荷的运行特性并对其分类建模,采用功率平衡和储能充放电功率为约束,建立以用电成本和负荷峰值平均功率比为目标的负荷优化调度模型;其次,以自适应惯性权重和均值欧氏距离等策略对多目标粒子群算法进行改进,并用改进算法对建立的模型进行优化求解;最后,用实际算例进行仿真,验证所提模型和算法的可行性与有效性,为用户参与需求响应提供了多种参考方案。

基于NOMA-OFDM的雷达通信一体化波形设计

针对基于正交频分复用的雷达通信一体化波形设计中,通信信息的随机性会影响雷达性能以及过高峰均包络比(PAPR)可能导致信号在射频端出现严重失真的问题,文中提出了利用非正交多址将雷达信号与通信信号在功率域中分开,以降低通信信息随机性对雷达性能的影响,并利用主动星座图扩展(ACE)对叠加信号进行PAPR抑制的波形设计方法。首先,分析了传统功率分配原则导致叠加星座出现混叠的原因,并给出在不同调制阶数的最佳功率分配;其次,从理论上分析了ACE技术对叠加信号进行PAPR抑制的可行性;最后,仿真结果表明,在不同调制方式和不同信噪比下,当功率分配最佳时能同时达成雷达信号高检测率和通信符号最低误码率。ACE技术的使用同时保证了优良的雷达性能和通信端的低误码率,对叠加信号的PAPR有较好的抑制效果。

一种 QAM星座点优化方法及性能分析

正交幅度调制(Quadrature Amplitude Modulation,QAM)是目前无线通信中大量应用的调制技术,其位于4个角的星座点易受链路的影响而导致较高误码率。提出了一种QAM星座点整形优化方法,并对整形优化后的QAM星座点性能进行了计算机仿真分析。以标准星座点为初始值,通过遗传算法逐步迭代,搜索出抗削峰的星座点,从而降低解调误码。仿真结果表明,相比标准QAM,整形优化后的星座点峰均比降低1 dB@1E-6,且在OBO=3.5 dB时有大约0.3 dB@SER=1E-3的解调增益提升。

广义频分复用系统峰均功率比抑制算法

为了降低广义频分复用系统存在着多载波系统中固有的高峰均功率比问题,本文提出了一种适用于广义频分复用系统的子载波抑制高峰均功率比算法。该算法以限幅法为基础,降低了系统的高峰均功率比,但与限幅法不同的是,该算法几乎不会对带外性能及误码率性能造成影响。由于子载波抑制高峰均功率比算法的峰均功率比抑制性能略差于限幅法,因此本文进一步提出将部分序列传输与子载波抑制高峰均功率比结合来进一步抑制系统高峰均功率比的算法。仿真表明:本文提出的算法的高峰均功率比抑制性能与限幅法相同,且不会对系统的带外与误码率性能造成影响。

基于电源调制的L波段高性能GaAsHBT功率放大器

介绍了一种基于GaInP/GaAs异质结双极晶体管(HBT)工艺、电源调制的高峰均比、高功率附加效率L波段功率放大器芯片,可满足多载波聚合、大容量通信系统的要求。从器件层面控制基极表面复合、寄生电阻和电容,实现低膝点电压、跨导均匀的晶体管;在电路层面采用自适应偏置电路和谐波调谐等提升线性和功率附加效率。该放大器采用前级驱动加末级输出、驱动比为1∶6的两级晶体管架构和高低通搭配的匹配电路。测试结果表明,在5 V偏置电压下,该功率放大器的饱和输出功率大于35 dBm;在大功率回退时(8 dBm),增益变化小于2 dB,功率附加效率指标达到50%;对于调制带宽为25 kHz的16进制正交振幅调制(16QAM)通信系统,邻道功率比小于-38 dBc@27 dBm。

基于数据失真的雷达通信一体化OFDM波形设计方法

正交频分复用(OFDM)波形设计是实现雷达通信一体化的物理层关键技术之一。OFDM波形通常存在峰均功率比(PAPR)高,以及波形自相关旁瓣电平高的问题。该文针对现有联合降低PAPR和自相关旁瓣方法存在的通信速率下降问题,提出了一种基于数据失真的一体化波形设计方法。该文还将通信数据的误差矢量幅度作为优化目标之一,降低了数据失真引起的通信误码率。首先,构建了PAPR约束下最小化积分旁瓣比和误差矢量幅度的优化模型。其次,根据调制星座图特点,通过外围星座调制的数据失真和所有调制数据失真,将多目标高维非凸优化问题转化为两个单目标优化子问题,分别采取凸松弛操作和交替方向乘子法(ADMM)求解简化后的子问题,得到低积分旁瓣比波形和PAPR约束下的低误差矢量幅度波形。仿真结果表明该方法设计的一体化波形可满足PAPR要求,同时具有良好的感知和通信性能。

面向混合波束成形结构的改进SLM算法

在大规模多输入多输出系统中,峰均功率比(PAPR)是影响发射机性能的主要因素之一。传统的PAPR降低方法都是基于全数字编码结构,无法有效地降低混合波束成形结构中发射天线端信号的PAPR。为解决这一问题,提出一种改进选择性映射(SLM)算法,该方法对输入信号进行独立的相位旋转并计算发射天线端信号的PAPR,最后选取PAPR最小的一组信号进行发送。此外,还分析了使用该算法下发射天线端信号PAPR的上界和下界。理论分析与仿真结果显示,改进SLM算法能够有效地降低混合波束成形结构发射天线端信号的PAPR。