共查询到18条相似文献，搜索用时 140 毫秒
1.
提出单源、多中继、单目的节点的放大转发中继系统中一种新的中继选择算法.考虑源端通过反馈获得第一跳链路过时(延时)的瞬时信道状态信息,推导了中继选择方案的中断概率闭式表达,并基于该表达式,以最小化条件中断概率为目标,提出利用信道相关性信息辅助的中继选择新方案.仿真验证了新方案相比于传统方案有明显的性能增益. 相似文献
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综合考虑业务时延敏感特性和信道质量,给出时变信道下多用户系统有效容量表达式,提出基于有效容量的多用户功率分配算法(MPAS).仿真结果表明,与最大化吞吐量为目标的注水算法和用户功率分配次优算法相比,MPAS能够获得10%~20%的有效容量增益,有效地满足业务的时延要求. 相似文献
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针对无线协作多播网络中的能量效率问题,设计了一种基于功率控制的能效优化策略。通过采用功率控制因子来限制系统总的能耗,按照最小信噪比原则进行中继节点选择,来增加系统吞吐量。该策略合理分配了基站和中继节点的功率,扩大了系统的覆盖范围,提高了发射效率。仿真结果表明了,与传统传输机制相比,完全搜索算法和变功率中继选择算法在效率方面有了较大提高,而时间分配算法则找到了最优的转发时间比例。 相似文献
4.
本文针对嵌入式手持设备中无线通信模块数据传输速率较低的问题,提出一种基于WLAN模块进行数据传输的方法.文章给出了BGW211模块的硬件连接图,并基于Linux操作系统开发了设备驱动程序.测试结果证明设计方案完全可行. 相似文献
5.
针对正交频分多址无线蜂窝系统下行链路,提出一种基于用户速率调和均值公平的多小区干扰协调功率分配算法.为了优先减轻小区边缘用户的同频干扰,把多小区功率分配问题建模为一个以用户速率调和均值公平为目标的非凸优化问题,并提出一种迭代算法求其接近最优解.该算法需要相邻的基站通过交互干扰信息进行相互协作.仿真结果表明,该算法在保证小区中心用户有较高通信速率的同时,极大提升了小区边缘用户的通信速率. 相似文献
6.
多用户MIMO-OFDM系统中基于迫零波束成型的自适应资源分配算法 总被引：2，自引：0，他引：2
针对多用户环境下的多天线正交频分复用下行系统,提出了2种有效的基于迫零波束成型的自适应资源分配算法.所提算法在保证每个用户的速率要求的情况下,通过自适应的功率、子载波和比特分配,最小化系统的发送功率.仿真结果表明,提出的2种次优的分配算法在满足用户的速率要求下能达到很好的系统性能. 相似文献
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在电能表数据传输过程中,由于受传输信道介质自身特性和外界环境干扰的影响,导致数据传输错误,为提高通信的可靠性,常采用差错编码方式纠错。介绍几种常用的通信差错控制编码方式的原理,并给出相应的实现方法。 相似文献
9.
在基于802.16j的无线中继网络中,考虑路由和调度的联合优化问题,最小化系统总调度时间. 首先采用线性规划的方法建立路由,进行链路业务速率分配,然后基于平移和交换思想提出一种链路调度算法. 理论分析证明所提算法的性能在最坏情况下,不会超过最优性能的1.5倍. 仿真结果表明,所提算法的平均性能非常接近最优性能. 相似文献
10.
任宝英 《内蒙古科技与经济》2011,(23):64-67
文章分析研究了网络拓扑结构、设备选型、保护方式、时钟同步等技术方案,根据理论知识计算分析了各局点话务量、局间中继电路数量及中继距离长度,确立了网络组织结构和具体的时隙分配方式。由于细致研究了SDH网的保护方式、时钟特性、工程计算等理论,使网络的安全性、实用性得到了保证。 相似文献
11.
Cheng-Chun Chang Tien-Ying Kuo Yi-Chung Lo Heung-No Lee David Askey Zhi-Hong Mao 《Journal of The Franklin Institute》2012,349(3):879-890
In recent years, more and more point-to-point communication systems involve simultaneous transmission of multiple sources of human perceptual data over a single communication medium. For example, in a teleoperation system or a telerobotic system, streams of video, audio, and haptic data need to be sent from a field place to a remote human operator. Each type of data demands a certain range of transmission rate. This creates conflicts among these data when the available bandwidth is limited.In this paper we study the bandwidth allocation for multiple sources of human perceptual data transmitted over a rate-limited communication channel. We aim to maximize the overall user satisfaction in the data transmission, and formulate an optimization problem for the bandwidth allocation. Using either the logarithmic or exponential form of human perceptual satisfaction function, we are able to derive closed-form solutions for the optimization problem. We show that the optimal bandwidth allocation for each type of data is piecewise linear with respect to the total available bandwidth. 相似文献
12.
《Journal of The Franklin Institute》2023,360(10):6693-6711
In this paper, we consider the discrete memory-less three-way degraded broadcast channel (3WDBC). The main contribution of this paper is in characterizing the capacity region of the discrete memoryless 3WDBC. To end up with this goal, we first develop the achievable region. Then, an outer bound to the capacity region is also derived. Next, the achievable region is shown to meet the outer bound such that the capacity is achieved. After that, the 3WDBC is shown to encompass many well-known multi-user networks such as (i) broadcast channel, (ii) multiple access channel, (iii) two-way channel, and (iv) relay channel. Further, the achievable capacity region is then extended to the additive Gaussian noise channel. Specifically, superposition encoding is employed at each user such that a given user can appropriately allocate its power to broadcast to the other two users. In this direction, two design criteria are theoretically presented and numerically investigated to show the range that the power allocation factor at each user may have. 相似文献
13.
Xiaowei Jiang Xiangyong Chen Junwei Hu Huaicheng Yan Mingfeng Ge 《Journal of The Franklin Institute》2019,356(6):3353-3367
In this paper, the achievable tracking performance limitations of discrete-time, multi-input multi-output (MIMO) networked control systems (NCSs) are studied. The channel is modeled as an additive white Gaussian noise and signal-to-noise ratio (SNR) limited channel with feedback. Under this framework, the closed relationships among stabilization, tracking performance, and SNR limited are quantitatively revealed. Some new results a.erived according to the allpass factorization and Youla parameterization of two degrees of freedom controller. The results show that the best tracking performance is in connection with the unstable poles, non-minimum phase zeros of the system. It is also demonstrated that the tracking performance will be badly degraded by feedback channel noise and due to the SNR limited. Finally, a simulation example is presented to validate the conclusions. 相似文献
14.
P. Varzakas 《Journal of The Franklin Institute》2006,343(3):295-300
The spectral efficiency of a multi-carrier direct-sequence code-division multiple-access (MC/DS-CDMA) system operating in a Rayleigh fading environment is investigated and evaluated in terms of the theoretically achievable channel capacity (in the Shannon sense) per user, estimated in an average sense. This short paper covers operation of the considered system over broadcast communication randomly time-varying channels as applicable to wireless radio networks and single-cell indoor mobile systems and leads to the derivation of a closed-form expression for the achieved spectral efficiency. Furthermore, the relation between the number of the employed sub-carriers and the achieved spectral efficiency is revealed. 相似文献
15.
Timothy S. Farajian 《Journal of The Franklin Institute》2007,344(5):426-438
Vibration suppression of a structurally damped beam via open and closed-loop controls is investigated. In doing so, minimization of a weighted, energy-based performance measure leads to closed-form expressions for optimal open-loop parameters in terms of feedback gains. The control problem is then completed by optimizing these feedback parameters numerically. Methods to determine optimal terminal time of control are also presented. Furthermore, techniques are established to optimize the response and performance of a system experiencing a known feedback time delay. Different types of optimization are proposed and, for each one, the trade-off between performance and computational efficiency is fully discussed. 相似文献
16.
Approximate mathematical form expressions were derived for the estimation of the average (ergodic) capacity and the average bit error rate of a log-normal free space optical channel in the cases of weak to moderate atmospheric turbulence conditions. We investigate the average capacity, the average bit error rate and the outage probability of free space optical communication channels using the frequentist and the Bayesian approach. Emphasis is given on the cases of weak to moderate atmospheric turbulence leading to channels modeled by log-normal distributed intensity fading. Furthermore, accurate approximate closed-form expressions and estimation procedures for their achievable capacity as well as their bit error rate and the important parameters of interest are derived. The derived approximate analytical expressions are verified by various numerical examples and simulations. Moreover, each methodology is reviewed in terms of their analytic convenience and their accuracy is also discussed. 相似文献
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《Journal of The Franklin Institute》2022,359(9):4605-4622
A class of extended state observers with fractional power function for compound disturbance is discussed in this paper. Disturbances are approximated in sinusoidal and polynomial forms. A detailed disturbance modeling process is given. Using the effect of non-smooth feedback on disturbance suppression and error decay rate, a class of extended state observers with fractional power function is proposed. Asymptotic convergence analysis shows that the effectiveness of compound disturbance rejection is improved. Numerical simulations are carried out to demonstrate its improvement on compound disturbance. 相似文献
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载波通信投资少,见效快,是电力调度通信的重要手段,而数字载波是必然的发展方向。为此,介绍了数字载波的优点、技术现状及其实际应用,并针对其不足之处,从载波网络管理、动态码速传输和载波频率分配及增加通信带宽等方面提出了改进建议。 相似文献