一种高可靠大容量星载存储器的设计与研究

凭借着存储密度大和存储速率高的特点,基于NANDFlash的大容量存储器在星载存储领域得到了广泛的应用,由于NAND Flash本身存在缺陷,基于NAND Flash的大容量存储器在恶劣环境下的可靠性难以保证.提出了通过FPGA设计SRAM对关键数据三模冗余读取和缓冲、NAND Flash阵列热备份和数据的回放校验以及合理的坏块管理等措施,实现了高可靠性的大容量存储器.实验说明该系统不会因为外在偶然因素而造成数据的不完整,而且整个存储系统的成本开销相对于目前的星载存储器也非常低.     

基于部分频率复用的多小区协作方案及容量分析

针对无线蜂窝网中的小区间干扰问题,给出一种基于部分频率复用的多小区协作传输方案.该方案将小区用户划分为中心用户和边缘用户,中心用户采用频率复用因子为1的本地基站通信,边缘用户采用频率复用因子为3的多基站协作通信,并通过对多个小区的基站进行功率控制,达到抑制小区间干扰、提高系统容量的目的.数值分析表明,相对于传统多小区蜂窝系统(Traditional Multi-Cell System,TMCS)和广义分布式天线系统(Generalized Distributed Antenna System,GDAS),所提多小区协作蜂窝系统(Multi-Cell Cooperative System,MCCS)可以有效地克服小区间干扰,提高系统容量.     

基于劳伦多项式的LAS码构造及性能分析

对基于Hadamard矩阵的LA码和基于劳伦多项式(Laurent Polynomial)的LS码的生成及相关特性进行研究,从占空比、相关特性、零干扰窗长度、码字总数等方面仿真分析了LAS码的性能,并结合实际应用,理论分析了LAS-CDMA系统与传统CDMA系统的归一化容量,仿真比较了LAS码和Gold序列在准同步CDMA系统中的误码性能.仿真和理论分析表明:LAS码具有均匀的零干扰窗(Interference Free Window,IFW)特性;不同主码的互相关函数IFW附近存在较小的副峰,多址干扰较小;在准同步移动通信系统中,LAS-CDMA抗多址干扰性能明显优于传统CDMA系统,使用LAS码比使用Gold序列有更好的误码性能.     

抑制LTE系统小区间干扰的软频率复用改进方案

为提高系统性能,LTE系统可通过频率复用因子（Frequency Reuse Factor,FRF）为 3的软频率复用（Soft Frequency Reuse,SFR）方案来有效抑制小区间的同频干扰,但在小 区峰值速率和系统容量方面仍有改善空间,由此介绍一种FRF为7的SFR方案,并结合与之相 适应的资源调度策略,可较大地提高小区边缘用户的峰值速率,使系统容量得以提升。     

基于量子粒子群算法的MIMO 信道容量优化

MIMO技术是一种很有潜力的新一代无线通信领域的关键技术,其高信道容量是最具吸引力的地方,但是其信道容量的实现受到多种因素的影响。综合考虑影响其容量的各个环节,仔细分析了其中几个关键因素并给出了相应的仿真。为了最大限度地实现高信道容量,依据量子粒子群优化算法,结合理论分析给出了惩罚函数,并构造了基本粒子,这样根据迭代函数就可以求出最佳粒子,依照此最佳粒子就可以合理优化设计MIMO系统。     

雷达软件测试用例复用技术研究

为了提高测试用例继承中缺陷发现效率,提出了一种有效的雷达软件测试用例复用模型,并将其应用到雷达软件测试用例优化设计中.根据工程实际情况,在公共测试用例库的基础上,以提高测试效率、降低测试成本为目标函数,采用蚁群算法进行用例集的寻优,给出复用用例的筛选、简化、抽象和适应性修改方法;以复用用例测试执行结果作为评估依据,持续改进和更新复用用例数据库,实现高执行率和成功率的测试用例复用.     

Effective capacity of a correlated Nakagami‐m fading channel

The grail of next‐generation wireless networks is providing real‐time services for delay‐sensitive applications, which require that the wireless networks provide QoS guarantees. The effective capacity (EC) proposed by Wu and Negi provides a powerful tool for design of QoS provisioning mechanisms. In this paper, we intend to generalize their formula for the effective capacity of a correlated Rayleigh fading channel; specifically, we derive a closed form approximate EC formula for a special correlated Nakagami‐m fading channel, for which the inverse of the correlation coefficient matrix is tridiagonal. To verify its accuracy via simulation, we develop a Green‐matrix based approach, which allows us to analytically obtain the effective capacity (given the joint probability density function of a correlated Nakagami‐m fading channel) while being able to simulate the corresponding channel gain process. Simulation results show that our EC formula is accurate. Furthermore, to facilitate the application of the EC theory to the design of practical QoS provisioning mechanisms, we propose a simple algorithm for estimating the EC of an arbitrary correlated Nakagami‐m fading channel, given channel measurements; simulation results demonstrate the accuracy of our proposed EC estimation algorithm showing its suitability in practice. Copyright © 2011 John Wiley & Sons, Ltd.     

Power‐efficient resource allocation with QoS guarantees for TDMA fading channels

This paper proposes two power‐efficient resource allocation policies with statistical delay Quality of Service (QoS) guarantees for uplink time‐division multiple access (TDMA) communication links. Specifically, the first policy aims at maximizing the system throughput while fulfilling the delay QoS and average power constraints, and the second policy is devised as an effort to minimize the total average power subject to individual delay QoS constraints. Convex optimization problems associated with the resource allocation policies are formulated based on a cross‐layer framework, where the queue at the data link layer is served by the resource allocation policy. By employing the Lagrangian duality theory and the dual decomposition theory, two subgradient iteration algorithms are developed to obtain the globally optimal solutions. The aforementioned resource allocation policies have been shown to be deterministic functions of delay QoS requirements and channel fading states. Moreover, numerical results are provided to demonstrate the performance of the proposed resource allocation policies. Copyright © 2010 John Wiley & Sons, Ltd.     

波束波导传输系统与天线设计

波束波导传输系统具有功率容量高、不需要旋转关节等优点,非常适合在大功率微波系统中应用。本文简单介绍了波束波导系统,设计了一款基于波束波导传输系统的天线,讨论了其馈源的设计及镜面的选取,并利用基于GRASP软件的QUAST模块进行了优化分析。为进一步验证GRASP计算的可靠性,将波束波导天线前两个反射面在HFSS中进行了仿真,并与GRASP所得结果进行了比较,比较结果显示两者吻合较好。     

赣韶铁路中间站蓄电池容量计算及结果修正

赣韶铁路是国家Ⅰ级铁路,联通京九、京广两大繁忙干线,其通信系统在保障铁路安全行车及数据传输发挥重要作用。作为通信系统稳定运行的基础,通信电源系统的合理设计不容忽视。文中从赣韶铁路通信电源系统蓄电池容量设计入手,通过收集整理通信设备耗电量数据,根据规范中计算公式确定式中各变量数值从而计算蓄电池容量,结合现行规范、补充条文、铁道部有关文件等对计算数据进行合理分析,并进行修正,最终得出蓄电池容量的合理数值。