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随着通信技术的迅速发展,在无线通信领域,无论是GSM,TD-SCDMA,WCDMA,CDMA2000,WLAN,LTE,还是LTEA、WiMax2等都有各自独立的优缺点,任何一种无线通信技术都不能独立支持所有业务的发展,多种技术的共存与融合将会成为未来移动通信网络发展的趋势。基于LTE-A(TDD)和WiMax2网络融合的可行性研究成果,提出了一种异构网络下基于相对信号强度,滞后差值和触发时长作为判断准则的垂直切换算法。最后,采用MATLAB仿真工具,建立LTE-A(TDD)与WiMax2混合组网的仿真模型,来验证该算法的可行性。 相似文献
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功率电平是TDMA、CDMA无线通信网络中最基本的参数。文中叙述了利用几种常用传统仪器测量TDMA(GSM)和CDMA功率电平(传导功率)的结果及误差分析,介绍了TDMA(GSM)、CDMA基站功率等级配置及误差容限,重点分析了TDMA(GSM)、CDMA(IS-95)的功率电平特征及测量方法,简述了复合数字调制格式功率计的技术性能和特点,并与矢量信号分析仪的测量结果进行了比较。 相似文献
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基于循环谱相关方法的MFSK信号识别 总被引:2,自引:1,他引:1
由于通信信号调制样式复杂多样,如何有效地识别通信信号调制类型是一个十分重要的课题。传统的信号处理都是假设所要处理的信号为随机平稳信号,但是在实际应用中,通信信号具有循环平稳性,是一种特殊的非平稳信号。首先介绍了循环平稳信号的特性循环谱相关概念,推导出MFSK信号的循环谱相关函数,分析了MFSK信号特征谱规律和可用于类内识别的特征参数,设计出MFSK信号的类内识别算法,仿真实验表明该算法能有效区分MFSK信号,并且在低信噪比下识别效果良好。 相似文献
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Mugen Peng Qianqian Zhang Wenbo Wang 《International Journal of Communication Systems》2008,21(12):1285-1306
A hierarchical convergence mechanism for the heterogeneous wireless communication system via the heterogeneous cooperative relay node is presented in this paper, in which the techniques of cooperative communication and wireless relay are utilized to improve performances of the individual user and the overall converged networks. In order to evaluate the benefits of the proposal, a utility-based capacity optimization framework for achieving the heterogeneous cooperative diversity gain is proposed. The heterogeneous cooperative capacity, relay selection and power allocation theoretical models are derived individually. The joint optimization model for relay selection and power allocation is presented as well. Owing to the computation complexity, the sub-optimal cooperative relay selection algorithm, the sub-optimal power allocation algorithm and the sub-optimal joint algorithm are determined to approach the maximum overall networks' spectrum efficiency. These proposed algorithms are designed in conformance to guarantee the equivalent transmission rates of the different wireless access networks. The simulation results demonstrate that the utility-based capacity model is available for the heterogeneous cooperative wireless communication system, and the proposed algorithms can improve performances by achieving the cooperative gain and taking full advantage of the cross-layer design. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Aiming at the problem that in the process of network fault detection and diagnosis,how to train the precise fault diagnosis and detection model based on small data volume,a fault diagnosis and detection algorithm based on generative adversarial networks (GAN) for heterogeneous wireless networks was proposed.Firstly,the common network fault sources in heterogeneous wireless network environment was analyzed,and a large number of reliable data sets was obtained based on a small amount of network fault samples through GAN algorithm.Then,the extreme gradient boosting (XGBoost) algorithm was used to select the optimal feature combination of input parameters in the fault detection stage and completed fault diagnosis and detection based on these data.Simulation results show that the algorithm can achieve more accurate and efficient fault detection and diagnosis for heterogeneous wireless networks,with an accuracy of 98.18%. 相似文献
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软件定义网络( SDN)为实现异构无线网络中的负载均衡提供了新的思路。设计了一种软件定义的无线网络负载均衡架构,并提出对应算法。首先,根据接收信号强度构建候选网络列表;其次,根据各候选网络的可用负载比率标准差进行负载差异分级;再次,将服务质量匹配度函数和负载均衡指数线性组合成联合优化函数,并根据负载差异分级对联合优化的权重进行动态调整,合理设置门限进行接纳控制。与传统算法相比,所提算法一方面可使各类业务阻塞率明显降低大约20%,另一方面使不同网络的归一化负载更加接近。该算法在进行网络负载均衡的同时,能够有效降低业务阻塞率,从而有效提升异构无线网络的整体性能。 相似文献
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S. Mojtaba Matinkhah Siavash Khorsandi Shantia Yarahmadian 《International Journal of Communication Systems》2014,27(7):1020-1033
In heterogeneous wireless access networks, each mobile terminal may frequently need to change its base station (BS); this change is called a ‘handoff’. BSs have static parameters, which are related to their radio access technologies (RATs); however, they also contain dynamic parameters such as load and signal quality. Therefore, the problem of handoff decision includes two subproblems of RAT selection and BS selection. In this paper, first a ‘heterogeneous handoff management system’ for gathering all different required parameters is proposed. Second, a RAT Selection algorithm based on analytic hierarchy process and a BS Selection algorithm based on data envelopment analysis are designed. Finally, by means of ‘weight restriction’ technique, we develop a method for studying the impact of RAT Selection parameters on the performance of the network. Simulation results indicate that RAT Selection parameters have significant impact on the bandwidth utilization, energy consumption and the whole satisfaction of the users in heterogeneous wireless access networks.Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Kuan‐Lin Chiu Yuh‐Shyan Chen Ren‐Hung Hwang 《International Journal of Communication Systems》2011,24(6):789-809
The next generation wireless communication system will likely be heterogeneous networks, as various technologies can be integrated on heterogeneous networks. A mobile multiple‐mode device can easily access the Internet through different wireless interfaces. The mobile multiple‐mode device thus could switch to different access points to maintain the robustness of the connection when it can acquire more resources from other heterogeneous wireless networks. The mobile multiple‐mode device therefore needs to face the handover problem in such environment. This work introduces Session Initiation Protocol (SIP)‐based cross‐layer scheme to support seamless handover scheme over heterogeneous networks. The proposed scheme consists of a battery lifetime‐based handover policy and cross‐layer fast handover scheme, called the SIP‐based mobile stream control transmission protocol (SmSCTP). This work describes the major idea of the proposed scheme and infrastructure. The proposed scheme has been implemented in Linux system. The simulation and numerical results demonstrate that the proposed SmSCTP scheme yields better signaling cost, hand‐off delay time, packet loss and delay jitter than SIP and mSCTP protocols. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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无线电监测频谱数据中包含有大量的信号,准确提取这些信号有利于掌握全频段的频谱使用情况。实际信号的频谱由于受噪声干扰,会出现信号频带内个别频点能量值低于检测门限的情况,此时传统的门限检测算法会将该信号错估为多个信号,产生多个虚假的相邻信号间隔,导致频谱信号提取的准确率下降。对此,根据虚假相邻信号间隔特点,提出一种自适应估计信号个数的频谱信号提取算法,该算法可自动、准确估计频谱监测数据中电磁信号的个数,并将对应的信号及频谱信息提取出来。实验结果表明,该方法具有自适应性、强鲁棒性和高准确性,有效提高了频谱信号提取的准确率,为军、民电磁环境的识别与掌握提供基础的电磁信号数据支撑。 相似文献
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由于直扩信号(Direct Sequence Spread Spectrum, DSSS)通常淹没在噪声中,为了有效地识别直扩信号、跳频信号(Frequency Hopping Spread Spectrum, FHSS)和常规调制信号,提出基于瞬时特征和高阶累积量的识别算法。首先推导证明了FM、MFSK、MPSK、DSSS、FHSS信号的归一化四阶累积量切片 是相同的,并推导得到AM和MQAM的 通用公式。然后,利用归一化四阶累积量切片 特征参数检测噪声中通信信号,利用占用带宽特征参数将信号分为扩频信号和常规调制通信信号两类;最后利用瞬时特征参数和高阶累积量特征参数,分别识别扩频信号和5种常规调制通信信号。仿真结果表明,当信噪比高于1dB时,该算法对上述7种信号的正确识别率可达到100%。 相似文献