降低DMT系统发送峰值的优化映射方法

针对ＤＭＴ ＡＤＳＬ（ＤＭＴ线路码非对称数字用户环路）传输系统发送信号幅值尖峰问题，提出了一种降低发送信号最大峰值同时又不损失系统传送信息的非线性优化映射方法。通过最优化方法合理地设计了一组可逆映射器，该方法比目前ＡＤＳＬ系统的硬限幅方法能较大幅度地压缩系统的动态范围或在相同的动态范围下获得更好的传输性能。     

一种新的扩频通信系统

多载波与扩频技术相结合,形成多载波扩频技术,现在已成为移动通信领域的研究热点.多载波扩频技术主要有两类,一类是频域扩频,另一类是时域扩频.本文提出将时域扩频与频域扩频相结合的多载波扩频系统方案,并进行了系统性能分析.     

DWMT系统中的信号映射方法

本文利用ＤＷＭＴ系统的特点，给出了一种将多个子信道组合在一起的多维信号星座映射方法。     

基于FPGA电力线多载波发送系统的实现

为克服电力线通信过程中的干扰,在电力线单载波通信的基础上,提出多载波传输系统的设计。该设计综合了多载波传输技术与分集合并接收技术,从而达到增强信息传输可靠性的目的。本设计基于FPGA设计语言,在Nexys3开发平台上搭建发送系统,通过串口接收上位机信号,整理封装成帧,并采用数字方式产生多载波信号进行发送。     

CMFB-DWMT多载波系统与DMT多载波系统的比较

本文首先讨论了基于余弦调制滤波器组（cosine modulation filter-banks-CMFB)的多载波调制解调结构的快速实现。然后在性能和抗噪方面对CMFB多载波结构与DMT（discretemulti-tone)作了分析和比较。计算机仿真结果显示，CMFB－DWMT(discrete wavelet multi-tone）在左频域特性、抑制噪声和抑制突发错误方面比DMT有较大的优势。     

一种降低FBMC-OQAM系统PAPR的ASSABC-PTS算法

针对滤波器组多载波-偏移正交幅度调制技术(Filter Bank Multicarrier-Offset Quadrature Amplitude Modulation,FBMC-OQAM)存在峰均功率比(Peak-to-Average Power Ratio,PAPR)过高的问题,以及传统部分传输序列(Partial Transfer Sequence,PTS)算法对PAPR抑制效果不明显,提出了一种新的基于自适应搜索策略的人工蜂群部分传输序列算法(Adaptive Search Strategy Based Artifical Bee Colony PTS,ASSABC-PTS)。首先,根据FBMC-OQAM系统特性,利用传统PTS算法对系统进行初步优化,以降低FBMC-OQAM系统的PAPR;然后,针对PTS算法中存在的计算复杂度问题,引入人工蜂群(Artificial Bee Colony,ABC)算法进行优化;最后,在ABC算法中引入自适应搜索策略提升算法的局部寻优能力,加快ABC算法的收敛速度和搜索精度。仿真实验表明,ASSABC-PTS在有效降低系统算法复杂度的同时,也极大降低了FBMC-OQAM系统的峰均功率比。     

双参数logistic映射的同步方法

提出了一种新的通过双参数非线性反馈函数来实现一般logistic映射的驱动响应系统的同步方法，该方法能够避免现有的线性反馈和非线性反馈中出现的弱同步现象，并且在不同的参数空间下同样可以保证同步，对一般的logisdc映射普遍适用。本文重点论述了在2个参数控科下的非线性反馈的同步原理及性能，通过数值仿真验证了该算法的有效性和对噪声的顽健性，并说明了该算法在保密通信中的应用。     

基于广义猫映射的一种图像加密系统

本文首先将猫映射推广为广义猫映射,然后将图像的像素坐标和灰度作为广义猫映射的初始值,映射参数和迭代次数作为密钥,对图像进行加密。本加密方案具有置换、替代、扩散等加密系统的基本要素,能抗明文攻击和选择明文攻击,密钥长度可变,密钥空间巨大,密文和明文大小可变且相同,计算时间也较短,可用于图像和数据块加密后传输。     

一种未知非线性系统的自适应神经网络控制方法

神经网络用于控制，主要是为了解决复杂的非线性、不确定、不确知系统的控制问题。由于神经网络具有学习能力和自适应性，使神经网络控制能对变化的环境有自适应性，且成为基本上不依赖于模型的一类控制，介绍了一种未知非线性系统的自适应神经网络控制方法。     

基于非线性系统的小信号检测算法研究

本文研究了通信数据链系统的微弱小信号增强与接收检测算法。为了提升通信数据链系统中信号的接收性能,在低信噪比条件下,提出基于非线性系统的小信号检测算法。在非线性系统中,适当强度的噪声在一定程度上会增强输出信号的幅值,从而实现在强大的噪声背景环境下对微弱小信号的增强和检测功能。本文着重研究了非线性系统中的双稳态系统,分析了通信数据链系统中的 MSK 信号输入到双稳态系统中,利用 Matlab 仿真出输入非线性系统前后的信号时域频域波形图,进而分析了基于通信数据链系统的小信号增强与检测算法性能。Matlab 仿真结果表明,本文提出的算法可以有效改善低信噪比条件下的通信信号接收性能,在信号处理与接收领域有着重大的应用前景。     

正交多载波调制中峰值因子的一种减小方案

在多载波调制系统中，通常调制信号的平均功率恒定，且和实际发送的信息符号向量无关，此时，由N个子载波组成的多载波信号的峰值因子(PF)等于10lgN(dB)。提出了减小多载波调制系统中PF的一种方案，对于瞬时包络功率的最大值超过所给门限值的信息符号向量，所有子载波的幅度被降低至门限值，而对于瞬时包络功率的最大值低于门限值的信息符号向量，所有子载波的幅度被增大至门限值。采用这种方法，整个调制系统的PF被减小，而净比特速率保持不变，但系统的误比特率(BER)略为增加。     

On the capacity optimization in multicarrier channel operation

The transmission plan for a communications channel exploited in multicarrier mode involves the operational parameters and the prediction of the channel impairments with special consideration for the intermodulation noise generated by beating among carriers. The intermodulation noise is a driving factor in the design phase of a transmission plan as it seriously affects the C/N + 1 ratio of the carriers in the channel, being often the dominant factor. The transmission plan of a channel operated in multicarrier mode can be represented as an injective application between two sets: the carriers and the frequency slots of the channel. Classical combinatory laws allow for the prediction of the number of configurations that can be established with sets of unidimensional elements. However, if one of the sets has elements with non‐unidimensional attributes, the classical combinatory laws fail to predict the number of possible configurations. This is the case in multicarrier transmission plans, where the carriers have an associated bandwidth (attribute of the carrier) that typically occupy several frequency slots. In this paper, an expression for the prediction of the number of possible configurations in a transmission plan is derived. This expression permits to select the most appropriate method to achieve transmission plan optimization, as a function of the associated computational resources. The higher the number of configurations, the higher the options for the optimization of the transmission plan. Subsequently, the C/N + I ratio of the carriers can be increased and therefore the quality of the service and the use of the channels resources are improved. Investigation of the space of configurations show that the maximum number of possible configurations is achieved in the range of 70–90% of channel occupation, which converges with the typical operational use of satellite transponders in multicarrier operation. This discussion is applicable not only to the frequency domain but also to any other system where sets of elements with non‐unidimensional attributes have to be considered (time domain, space domain, etc.). Copyright © 2003 John Wiley & Sons, Ltd.     

一种实现非等带宽多载波调制的新方法

传统的多载波调制都是采用对传输信道进行等带宽划分的方式。为了更好地适应信道传输特性，一个很有应用前景的发展方向是采用非等带宽划分信道的多载波调制方式。本文提出了一种利用正交小波包变换实现的非等带宽划分信道的多载波调制方法。理论分析和实验结果表明，这种方法对于提高信道的传输性能有很大的潜力。     

Overlapped universal filtered multicarrier system for uplink wireless communication

Universal filtered multicarrier (UFMC) is a promising new waveform that eliminates cyclic prefix and performs filtering on a chunk of successive subcarriers. Therefore, it is suitable for applications with requirements on high spectral efficiency and low latency. However, the limited bandwidth may be an obstacle for reliable communication in frequency selective channels. This paper proposes a new transmitter structure for uplink wireless communication system based on UFMC waveform. The basic idea is to allow a user to transmit its information on more than one subband simultaneously, increasing its robustness against frequency selectivity. To eliminate the multiuser interference brought by the overlapped transmission strategy, an iterative receiver with parallel interference cancellation is designed. Rate analysis is provided to reveal the rationale of the proposed scheme. Simulations on the symbol error rate performance are conducted to validate the transceiver design. It is found that the proposed scheme outperforms existing UFMC design without sacrificing any other performance metrics with only moderately increased complexity.     

Selected mapping technique for reducing PAPR of single‐carrier signals

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.     

A new peak detection method for the three-phase sinusoidal signals

An instantaneous amplitude detection method for the three-phase sinusoidal signals is proposed. The proposed method can measure the amplitude of the three-phase signals without any delay by using only two of the three-phase signals. The performance of this method under the ideal and nonideal conditions is analyzed. To demonstrate the performance of the proposed method, an electronic circuit for implementing this method is developed and tested     

基于线性化Poincaré映射模型的非线性电力电子系统控制方法

非线性电力电子系统在进行动态性能分析的时候,经常会出现数据分析误差大、相关物理概念模糊不清的现象,相比之下,使用线性化Poincaré映射模型进行动态性能分析,其可靠性与转确性都有所提升.     

A study on the PAPRs in multicarrier modulation systems with different orthogonal bases

This paper studies the peak‐to‐average power ratios (PAPRs) in multicarrier modulation (MCM) systems with seven different orthogonal bases, one Fourier base and six wavelet bases. It is shown by simulation results that the PAPRs of the Fourier‐based MCM system are lower than those of all wavelet‐based MCM (WMCM) systems. A novel threshold‐based PAPR reduction method is then proposed to reduce the PAPRs in WMCM systems. Both numerical and simulation results indicate that the proposed PAPR reduction method works very effectively in WMCM systems. Copyright © 2006 John Wiley & Sons, Ltd.     

Research on the algorithm for reducing the PAPR of OFDM system based on quantum chaotic mapping

Aiming at the high peak to average power ratio (PAPR) problem of OFDM system,a modified selective mapping algorithm based on quantum loigstic chaotic map was proposed.To solve the problem of fixed point and stable window,the quantum loigstic chaotic maps were used as random phase sequence vectors,which provided a large number signals with fine correlation and random characteristics,easy to produce and regenerate.Matlab simulation results show that the proposed algorithm effectively reduces the PAPR,increases the numbers of candidate signals,cuts down the amount of redundant information transmission,bring down the side band power.The proposed scheme has a broad application prospect in OFDM system.     

虚拟网络可生存的启发式可靠映射算法

针对虚拟网络可靠映射问题,引入虚拟网络可生存约束条件,确保在底层网络单节点失效情况下,被映射虚拟网络剩余部分仍保持连通,最大程度确保虚拟网络的完整性和服务的连续性。以最小化底层网络映射开销为目标函数,建立虚拟网络可靠映射的整数线性规划模型,提出一种虚拟网络可生存的启发式可靠映射算法RHM-SVN并进行求解。实验结果表明,该算法能够有效降低资源平均利用率,提高映射成功率、底层网络平均收益和虚拟网络恢复成功率。