半导体激光器三阶载波互调非线性失真

对半导体激光器的P-I特性曲线的非线性引起的三阶载波互调非线性失真进行了理论分析,得出了减少非线性失真的方法,并在实验上获得了验证.     

Research on maximizing energy efficiency for relay-aided D2D communication

In order to optimize the energy efficiency for relay-aided D2D communication underlaying cellular network,an algorithm was proposed while guaranteeing the quality of service of D2D users and cellular users.Firstly,the problem was formulated as a mixed integer nonlinear fractional programming problem,with the goal of maximizing the energy efficiency of all D2D users.Then,the maximizing energy efficiency problem was divided into three sub-problems,such as power allocation,relay selection and subcarrier assignment.Finally,the power allocation problem,the relay selection problem and the subcarrier assignment problem were addressed by Dinkelbach method and Lagrange multiplier method,Q-learning and Hungarian algorithm,respectively.The simulation results show that the proposed algorithm can improve the total energy efficiency of D2D users compared with existing algorithms.     

认知OFDM系统中针对视频业务用户的资源分配

在多用户认知无线电OFDM系统中,针对实时视频业务用户,提出一种计算复杂度低的资源分配方案.该方案采用鱼群算法分配子载波,并提出简单功率干扰(Simple Power Interference,SPI)约束功率分配算法.目标是在满足总功率预算并且保证不干扰主用户的前提下,最大化系统的下行系统容量.仿真分析表明,在视频业务用户场景中,所提算法能有效提高下行系统速率,性能接近最优且复杂度低.     

小波包分复用系统子载波的构造及调制实现

小波包分复用(WPDM)系统中作为子载波的小波包基函数必须是连续解析的,但实际中很难得到,通常需要对其进行逼近.通过滤波器系数采用迭代卷积的方法来对小波包基函数进行离散逼近,构造出的子载波满足小波包基函数的正交性.同时用此方法实现了多载波调制,并将该系统与正交频分复用(OFDM)系统在多径时延信道下进行了比较.仿真结果表明,WPDM系统在抑制ISI和ICI方面以及对定时偏差的影响上更具优势.     

Radio resource allocation for interference management in mobile broadband OFDMA based networks

This paper focuses on the inter‐cell interference (ICI) management problem in the downlink channel for mobile broadband wireless OFDMA‐based systems. This subject is addressed from the standpoint of different interrelated resource allocation mechanisms operating in multi‐cell scenarios in order to exploit frequency and multi‐user diversity: ICI coordination/avoidance and adaptive subcarrier and power allocation. Even though these methods can be applied in a stand‐alone way, a significant performance improvement is achieved if they are jointly designed and operate in a combined basis. Several alternatives for mixed frequency and power ICI coordination schemes are proposed in this paper. Connected with a proper power mask‐based design, the potential gain of a flexible frequency sectorization solution, halfway between fractional/soft frequency reuse and pure frequency sectorization, is explored. The main objective is to outperform fractional/soft frequency reuse offering an attractive trade‐off between cell‐edge user data rates and average cell throughput. Proposals concerning ICI coordination/avoidance have been evaluated in combination with several heuristic adaptive subcarrier and power allocation algorithms. Copyright © 2009 John Wiley & Sons, Ltd.     

基于数据重构MNM的交织型OFDMA上行链路频偏盲估计

正交频分多址(OFDMA)系统同步问题的难点在于上行链路的频率同步,本文针对子载波交织分配的OFDMA系统上行链路,利用数据重构,提出一种基于MNM(Minimum-norm Method)算法的载波频偏盲估计算法,利用接收信号的周期性特点,在一个符号周期内以较小的计算量完成对各个用户的载波频偏估计.     

遥测技术在引信电源非接触测量中的应用研究

引信一般用一次性化学电池做能源，电池在高旋转和大冲击过载条件下激活发电，为了对电池在负载条件下的输出电压与输出噪声进行测试，往往需要在高速离心机上对电池进行动态监测，这就需要非接触动态测量系统。采用FM／FM体制的遥测系统来实现电池的动态测试，其特点是实时性好、抗干扰能力强、配置和操作灵活。调制器采用多路副载频调制方法，副载频解调采用集成锁相环路来实现，系统采用S频段晶控发射机，发射天线采用S频段片状微带天线，其体积小、重量轻。接收系统采用S频段点频接收机实现。系统标定、数据处理及结果输出等均由计算机来完成，对样机经现场考核和测试证明该系统工作正常，具有很好的实用性。     

毫米波副载波光纤通信技术的研究进展

综述了用于下一代移动通信的光纤毫米波副载波通信技术(ROF)的研究进展。介绍了系统的基本构想和涉及的关键技术。着重介绍几种毫米波副载波光发射器以及有关光学技术的新进展,包括外调制器方法、射频上转换法、光学外差法、毫米波调制光脉冲发生器等;简要介绍了ROF接收技术、系统技术和有关应用的研究动向。     

The Reserve/Maximum Capacity of Melatonin’s Synthetic Function for the Potential Dimorphism of Melatonin Production and Its Biological Significance in Mammals

In this article, we attempt to classify a potential dimorphism of melatonin production. Thus, a new concept of “reserve or maximum capacity of melatonin synthetic function” is introduced to explain the subtle dimorphism of melatonin production in mammals. Considering ASMT/ASMTL genes in the pseudoautosomal region of sex chromosomes with high prevalence of mutation in males, as well as the sex bias of the mitochondria in which melatonin is synthesized, we hypothesize the existence of a dimorphism in melatonin production to favor females, which are assumed to possess a higher reserve capacity for melatonin synthesis than males. Under physiological conditions, this subtle dimorphism is masked by the fact that cells or tissues only need baseline melatonin production, which can be accomplished without exploiting the full potential of melatonin’s synthetic capacity. This capacity is believed to exceed the already remarkable nocturnal increase as observed within the circadian cycle. However, during aging or under stressful conditions, the reserve capacity of melatonin’s synthetic function is required to be activated to produce sufficiently high levels of melatonin for protective purposes. Females seem to possess a higher reserve/maximum capacity for producing more melatonin than males. Thus, this dimorphism of melatonin production becomes manifest and detectable under these conditions. The biological significance of the reserve/maximum capacity of melatonin’s synthetic function is to improve the recovery rate of organisms from injury, to increase resistance to pathogen infection, and even to enhance their chances of survival by maximizing melatonin production under stressful conditions. The higher reserve/maximum capacity of melatonin synthesis in females may also contribute to the dimorphism in longevity, favoring females in mammals.     

多用户MIMO-OFDM系统中一种子载波分配算法

介绍了多用户MIMO-OFDM系统中的Hungarian子载波分配算法,然后针对其计算复杂度过高的缺陷,提出一种局部最优的子载波分配算法,并与Hungarian子载波分配算法进行仿真比较。结果表明,该算法使系统总数据速率仅下降1．7％,而其计算复杂度却大幅减小,提高了资源分配的效率,符合高速无线系统资源实时分配的要求。