同址干扰限制下跳频异步组网的频率分配方法

针对跳频电台多台同址时相互间同址干扰严重和采用分频段跳频方式导致跳频增益小的不足,从子网内、子网间和跳频同步信号无干扰3个层次分析跳频异步组网中的全频段宽间隔频率分配约束条件,并建立代价函数;根据约束条件的特点对模拟退火算法的实际应用进行改进,提出同址干扰限制下的全频段宽间隔跳频异步组网频率分配方法。计算机求解结果表明新方法可以很好地解决同址干扰限制下的跳频频率分配问题,提高跳频通信抗干扰性能,对跳频电台发挥性能优势具有重要意义。     

车载无线电台同址干扰测试与分析

同址干扰是车载、舰载、机载无线电通信中面临的一个重要问题,针对同址干扰对复杂通信系统的影响提出了一种有效的测试和分析方法;首先对车载电台的各种天线进行了耦合度测试,从实验和仿真两方面阐述了同址干扰的严重程度,为进一步定量分析同址干扰的影响,构建了有线测试平台;在需求分析基础上,详细介绍了平台的组成,并以短波、超短波电台为对象,通过大量现场实验,深入分析了误码率,同址工作电台的频率间隔和功率之间的相互关系;研究表明,同址干扰的定量分析是设计车载通信系统,合理分配电台工作参数的关键环节。     

车载跳频电台共址干扰研究及其优化

针对车载VHF跳频电台的共址干扰问题,建立一种定频模式下的共址干扰分析模型。分析共址干扰的主要影响因素,通过实验和理论研究对干扰功率、频率、误码率等重要参数进行定量分析,建立定频模式下的共址干扰分析模型。结合VHF组网的约束条件,提出一种跳频系统的误码率计算方法,并采用双层多目标算法,构建基于共址电台规模和频表分配的优化设计模型。实例分析表明,该模型可优化配置电台工作参数,有效降低共址跳频电台误码率。     

无线电通信中的同址干扰问题研究

针对战术电台车中无线电同址干扰对车载通信系统的影响,首次进行了全面、系统的研究。首先通过实验对车载天线之间的耦合度进行了测量,并结合Ansoft HFSS软件进行了仿真验证。在耦合度统计均值的基础上,通过分析电台射频前端的阻塞模型,以及射频前端各个部分的损耗、增益、噪声,对同址干扰引起的减敏影响进行了定性分析和定量计算,并通过经验公式对同址干扰中电台频率间隔与信噪比损耗之间的关系进行了仿真。最后,提出了减敏损耗与通信距离之间的等效计算,进一步分析了同址干扰对实际通信的影响。     

频谱管理中基于希尔伯特-黄变换的干扰诊断

为了给频谱管理的干扰协调机制提供科学有效的依据,在分析系统间EMC干扰的特点基础上,采用希尔伯特-黄变换分析接收机端的干扰信号样本的时-频信息、希尔伯特谱和边际谱,得到干扰信号的时频特征。采用多级频率搬移的方法,解决信号的经验模态分解中出现的模态混叠。文章以互调干扰信号的诊断分析为例,验证此法能够将互调干扰从信号样本中分离。     

频谱管理中基于希尔伯特-黄变换的干扰诊断

为了给频谱管理的干扰协调机制提供科学有效的依据,在分析系统间EMC干扰的特点基础上,采用希尔伯特-黄变换分析接收机端的干扰信号样本的时-频信息、希尔伯特谱和边际谱,得到干扰信号的时频特征。采用多级频率搬移的方法,解决信号的经验模态分解中出现的模态混叠。文章以互调干扰信号的诊断分析为例,验证此法能够将互调干扰从信号样本中分离。     

WLAN系统干扰分析与规避措施研究

分析WLAN系统工作机制、系统同频与邻频之间的干扰,从网络频率规划、设备自动配置和底层参数调整3方面研究了干扰规避措施及方案,在测试验证的基础上,提出了WLAN规划、优化中的频率规划原则、干扰规避措施和应用实施建议。     

用Laguerre滤波器实现自适应跳频同址干扰抵消

跳频同址干扰具有频率选择性,是典型的长脉冲响应干扰.Laguerre滤波器同时具有FIR和IIR滤波器的优点,对长脉冲响应干扰具有更优的匹配性能和稳定性.在研究跳频同址干扰多径信道特性的基础上,提出采用自适应Laguerre滤波器实现跳频同址干扰抵消,给出自适应干扰抵消器实现算法和自适应Laguerre滤波器最优极点估计方法.仿真结果表明基于Laguerre滤波器的自适应跳频同址干扰抵消器在恒参信道和时变信道中均能获得良好的抵消性能和稳定性,具有很好的实际应用价值.     

无线电电磁干扰分析和计算

本文分析了同频干扰、邻道干扰、互调干扰等3种无线电干扰的产生机理,提出了无线电同频干扰与邻道干扰基于定积分的计算方法;同时分析互调干扰的基础上引入了互调干扰的等效计算公式。最后,在频谱管理软件系统中实现了3种干扰样式的模拟计算,通过实验数据验证了干扰分析计算方法的正确性。     

移动通信无三阶互调频率的选择

<正> 前言移动通信,在我国已有了广泛的应用.随着移动通信的发展,为了增加通信容量和减小呼损率,在同一地区往往要求多种频率的电台同时工作;并且,由于移动通信的特点,干扰信号电平有时大大强于主信号电平.这样,由于电台发射机末级和接收机前级的非线性,互调干扰将不可避免的大量产生,而其中三阶互调干扰尤为严重.可以说,三阶互调干扰是移动通信中最主要的干扰,因此在移动通信的频率选择中必须考虑.移动通信无三阶互调频率的选择,可以通过查表求得〔1〕.但是,这种表并没有给出方法,而且只列出了10个频率以内的少数最佳频率序列,因此不能很     

一种基于选择性变异技术的频率分配方法

为了提高蜂窝网络中频率资源的利用率,提出一种基于选择性变异技术的频率分配方法。该方法将网络中的电磁干扰作为系统的能量函数,通过动态改变算法迭代过程中所需要满足的约束条件来实现频率配置的快速优化。仿真结果表明,其搜索效率远高于模拟退火算法以及微正则退火算法。     

多信道无线Mesh网络信道分配算法

针对无线Mesh网络的带宽容量问题,文章通过使用无线网络干扰协议模型对无线链路的干扰进行量化,利用整数线性规划公式对信道分配问题进行描述,在信道分配的时候,应用目标函数对无线链路的信道分配进行优化,使网络总的干扰权重最小化,在此基础上提出一个信道分配的启发式算法。仿真结果表明,文章提出的算法能提高网络的吞吐量。     

A hybrid hopfield network-simulated annealing approach for frequency assignment in satellite communications systems.

A hybrid Hopfield network-simulated annealing algorithm (HopSA) is presented for the frequency assignment problem (FAP) in satellite communications. The goal of this NP-complete problem is minimizing the cochannel interference between satellite communication systems by rearranging the frequency assignment, for the systems can accommodate the increasing demands. The HopSA algorithm consists of a fast digital Hopfield neural network which manages the problem constraints hybridized with a simulated annealing which improves the quality of the solutions obtained. We analyze the problem and its formulation, describing and discussing the HopSA algorithm and solving a set of benchmark problems. The results obtained are compared with other existing approaches in order to show the performance of the HopSA approach.     

Heuristic manipulation,tabu search and frequency assignment

Heuristic manipulation attempts to modify the search space of an optimization problem, using information provided by an underlying heuristic method. In this paper it is applied in combination with tabu search to the fixed spectrum frequency assignment problem.The frequency assignment problem involves the assignment of discrete channels (or frequencies) to the transmitters of a radio network, such as a mobile telephone network. Frequency separation is necessary to avoid interference by other transmitters to the signal received from the wanted transmitter at the reception points. Unnecessary separation causes an excess requirement for spectrum. Good assignments minimize interference and the spectrum required. In fixed spectrum frequency assignment the frequency spectrum available is given and the target is to minimize the interference in the network.Computational experiments confirm that the manipulation technique is able to drive the underlying tabu search algorithm towards improved solutions.     

基于两阶段迭代优化的空天观测资源协同任务规划方法

为提高空天观测资源协同观测能力,基于分而治之框架,提出一种两阶段迭代优化方法以解决空天观测资源协同任务规划问题.第1阶段,根据观测机会和冲突度构造适应度函数,基于适应度将任务分配到合适的子规划中心;第2阶段,子规划中心根据分配到的任务进行资源调度,得到各类观测资源的观测计划,并将资源观测方案和观测收益反馈给第1阶段.第1阶段再根据第2阶段的反馈结果,结合禁忌表策略,对任务分配方案进行迭代调整和更新,直到生成近似最优或满意的任务分配方案和资源观测方案.为验证所提出方法的有效性,开展大量仿真实验.实验结果表明,与最大权重最先分配算法、基于适应度的任务分配算法、基于资源优先度的任务分配算法相比,所提出方法在任务收益率方面提高了2.40%sim14.14%.研究成果可为空天观测资源传感网络的协同管控提供技术支持.     

Price-based interference avoidance game in the Gaussian interference channel

This paper considers a distributed interference avoidance problem employing frequency assignment in the Gaussian interference channel(IC).We divide the common channel into several sub-channels and each user chooses one sub-channel for transmission in such a way that the total interference in the IC is minimum.This mechanism named interference avoidance in this paper can be modeled as a competitive game model.And a completely autonomous distributed iterative algorithm called distributed interference avoidance algorithm(DIA)is adopted to achieve the Nash equilibrium(NE)of the game.Due to the self-optimum,the DIA is a sub-optimal algorithm.Therefore,through introducing an optimal compensation(or price)into the competitive game model,we successfully develop a compensation-based game model to approximate the optimal interference avoidance problem.Moreover,an optimal algorithm called iterative optimal interference avoidance algorithm(IOIA)is proposed to reach the optimality of the interference avoidance scheme.We analyze the implementation complexity of the proposed algorithm which is only O(N),with N standing for the number of users in the IC.We also give the proof on the convergence of the proposed algorithm.The performance upper bound and lower bound are derived for the IOIA algorithm.The simulation results show that the IOIA does reach the optimality under the condition of interference avoidance mechanism.     

一种遗传算法适应度函数的改进方法

针对简单遗传算法中线性适应度函数随进化过程恒定不变的缺点。提出一种可随进化代数动态调整的非线性适应度函数。以典型的遗传算法测试函数为算例，分别以Goldberg提出的线性拉伸方法与文中提出的改进遗传算法进行计算。计算结果表明文中提出的动态适应度函数对简单遗传算法的改进有较明显的效果。     

Particle swarm optimization-based DRWA for wavelength continuous WDM optical networks using a novel fitness function

Greater demand of bandwidth and network usage flexibility from customers along with new automated means for network resource management has led to the concept of dynamic resource provisioning in WDM optical networks where unlike the traditional static channel assignment process, network resources can be assigned dynamically. This paper examines a novel particle swarm optimization (PSO)-based scheme to solve dynamic routing and wavelength assignment (dynamic RWA) process needed to provision optical channels for wavelength continuous Wavelength Division Multiplexed (WDM) optical network without any wavelength conversion capability. The proposed PSO scheme employs a novel fitness function which is used during quantization of solutions represented by respective particles of the swarm. The proposed fitness function takes into account the normalized path length of the chosen route and the normalized number of free wavelengths available over the whole route, enabling the PSO-based scheme to be self-tuning by minimizing the need to have a dynamic algorithmic parameter ‘α’ needed for better performance in terms of blocking probability of the connection requests. Simulation results show better performance of the proposed PSO scheme employing novel fitness function for solving dynamic RWA problem, not only in terms of connection blocking probability but also route computation time as compared to other evolutionary schemes like genetic algorithms.     

Optimized planning of frequency hopping in cellular networks

We consider a generalization of the classical frequency assignment problem. The generalization arises when frequency hopping is used in a cellular network. The planning problem concerns assigning lists of frequencies to blocks of transceivers, such that the total interference is minimized. This problem is considerably more difficult than the classical frequency assignment problem, because of the large number of possible frequency lists. We provide the technical background that motivates our study, and present a mathematical model which includes the classical frequency assignment problem as a special case. We describe a simulated annealing algorithm. The algorithm explores the solution space by solving an integer program in each iteration. We report computational results for real-life and synthesized networks.     

基于遗传乌燕鸥算法的同步优化特征选择

针对传统支持向量机方法用于数据分类存在分类精度低的不足问题, 将支持向量机分类方法与特征选择同步结合, 并利用智能优化算法对算法参数进行优化研究. 首先将遗传算法(Genetic algorithm, GA)和乌燕鸥优化算法(Sooty tern optimization algorithm, STOA)进行混合, 先通过对平均适应度值进行评估, 当个体的适应度函数值小于平均值时采用遗传算法对其进行局部搜索的加强, 否则进行乌燕鸥本体优化过程, 同时将支持向量机内核函数和特征选择目标共同作为优化对象, 利用改进后的STOA-GA寻找最适应解, 获得所选的特征分类结果. 其次, 通过16组经典UCI数据集和实际乳腺癌数据集进行数据分类研究, 在最佳适应度值、所选特征个数、特异性、敏感性和算法耗时方面进行对比研究, 实验结果表明, 该算法可以更加准确地处理数据, 避免冗余特征干扰, 在数据挖掘领域具有更广阔的工程应用前景.