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本文针对无线接口主要讨论了通用移动电信系统UMTS(Universal Mobile Telecommunications System)规划和优化所面临的问题以及相应的解决方案。介绍了WCDMA的空中接口,提出了系统规划的方案,包括覆盖、容量、频率和码子的规划。同时讨论了WCDMA网络性能中关键的优化和监测指标。 相似文献
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介绍第三代移动通信系统相对于第二代系统的突出优点,给出UMTS的无线接口协议结构,简述服务接入点和服务原语,最后论述物理层提供的服务和功能。 相似文献
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Universal Mobile Telecommunications System (UMTS) is the main standard of the third generation of mobile communications and
its air interface is called WCDMA. This paper considers the effect of multiple access interference (MAI) on the uplink performance
of a simple WCDMA system. The transmitted signal of a defined user is destroyed by interferences from other users and executable
resolves are presented and applied. The performance measure is the probability of error, BER, for different number of users.
The results indicate that an increase in the number of users would degrade system performance considerably. Furthermore, the
channel effect on the signal quality is a problem in transmission that should be considered. The goal of this paper is the
observation of uplink performance in presence of MAI. Finally, we represent all ways for resolving the MAI as an undesired
effect. FDD mode has been chosen as the operation mode of transmission as well. We consider an identical user's power of received
signals at the base station.
Hassan Moradi received his B.S. degree in Electrical Engineering from Shiraz University, Shiraz, Iran in 1998 and the M.S. in communications
systems from K.N. Toosi University of Technology, Tehran, Iran in 2001. He joined the Iran Telecommunications Research Center
(ITRC) as an assistant researcher of wireless communications in 2001. Also, he is currently a member of technical staff of
ITRC. His current research interests are in Mobile Communications Network, Radio Transmission and Signaling Protocols. He
has authored several papers in the wireless communications field especially about access network of CDMA-based systems. Moreover,
after finishing Mobile Switching Center (MSC) project in ITRC, he now works and manages the Implementation Switch Lab project
at ITRC.
Mahdi Samie received his B.S. in Computer Engineering from Isfahan University of Technology (IUT), Isfahan, Iran, in 1996, and M.S. in
Computer System Architecture from Iran University of Science and Technology (IUST), Tehran, Iran in 2001. Since 1999 he is
teaching at the department of Computer Engineering in IUST. He joined the Iran Telecommunications Research Center (ITRC) in
September of 2001, where he is currently pursuing research on communication protocols for mobile networks as a Research Assistant.
His research interest includes Signaling Protocols, Mobile Network Protocols, mobile IP, Digital Transmission and Database
in Telecommunication Networks.
Maryam Fallah-Pour received the B.S. degree in Electrical Engineering from K.N. Toosi University of Technology (KNTU), Tehran, Iran in 2003.
Her primary current research interests are Industrial Control, Instrumentation, Control of Communication Systems, Software
and Hardware design of PLC systems, analysis and modeling of control systems. In addition, she is interested in simulation
and implementation of communications protocols. Now, addition to working at Patsa Industry group in Tehran, she is continuing
his studies as a M.Sc. student at KNTU. 相似文献
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研究了一个新的分数阶系统的混沌动力学行为.基于分数阶微积分理论和数值模拟,发现在该新的分数阶系统中存在混沌,并且得出该分数阶系统能产生混沌吸引子的最低阶数为2.49阶.根据分数阶动力系统稳定性理论,通过设计非线性控制器,实现了新的分数阶混沌系统的投影同步,该方法设计简便,并且不需要计算Lyapunov指数,数值模拟结果验证了该同步方法的有效性. 相似文献
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UMTS/WCDMA空中接口方案的物理层协议 总被引:1,自引:0,他引:1
简要介绍第三代移动通信系统的研究现状,并对欧洲通用移动通信系统UMTS/ W CDMA 空中接口方案的物理层协议进行深入探讨。 相似文献
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首先介绍了UMTS网络结构与接口协议栈,接着介绍了UMTS关键指标及相关过程,然后说明了UMTS关键指标的定义与实现。 相似文献
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在通用移动通信系统(UMTS)中,无论在无线接入部分还是在核心网部分,QOS的保证都是关键性问题。呼叫准入控制(CAC)是QOS机制的重要组成部分,本文根据3GPP对UMTS业务种类的定义及相应的QOS分类,对UMTS核心网络的QoS准入控制问题进行了研究。基于排队论的思想,提出了一种基于综合排队机制的CAC算法,并对其进行了相应的性能分析和仿真实验,结果表明了本算法的有效性。 相似文献
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UMTS核心网中基于区分服务的QoS控制模型 总被引:2,自引:0,他引:2
3G新业务的发展,要求UMTS提供端到端QoS控制。文章构建了在UMTS核心网中为不同业务类提供QoS保证的区分服务模型,提出了从UMTS业务类到DiffServ域服务等级的映射方案,设计了一种新的队列调度算法,采用优先级和分离机制,在流量调整器配合下可满足不同业务类的QoS要求。最后,通过模拟实验证明了模型的有效性。 相似文献
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总结了欧盟“先进的通信技术与业务(ACTS)计划”在全球卫星移动通信方面研究的进展,介绍了INSURED、NEWTSET、SECOMS、SINUS、TOMAS工程在网络集成、空中接口、移动终端等方面取得的成果,认为卫星移动通信在未来的全球移动通信系统(UMTS)中占有重要的地位。 相似文献
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描述了UMTS系统中移动到移动语音呼叫时两种提高语音质量的方法.即TFO(Tandem Free Operation)和TrFO(Transcoder Free Operation)机制。分析了他们的操作原理后。本文的主要贡献在于对二者的性能和优缺点做了深入的比较研究.并且就实现问题.给出了几种解决方案。 相似文献
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何丽娅 《南京邮电学院学报(自然科学版)》2007,27(6):72-75,80
分析了UMTS/WCDMA系统所产生的干扰对PAM—IR-UWB系统的影响,推导出了UWB系统在存在UMTS干扰下的误比特率公式,解析分析了UWB发射信号的基本参数与抗UMTS干扰能力之间的关系。数值计算和仿真验证了分析的正确性和UWB系统抗UMTS干扰的能力。 相似文献
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Antonios Alexiou Christos Bouras Andreas Papazois 《International Journal of Communication Systems》2009,22(6):739-754
In this paper, we study the applicability of multicast congestion control over universal mobile telecommunications system (UMTS) networks. We analyze two well‐known multicast congestion control schemes for fixed networks, namely TCP‐friendly multicast congestion control and pragmatic general multicast congestion control. We investigate their behavior when they are employed in UMTS networks and we analyze the problems arose when these mechanisms are applied over the wireless links of the UMTS terrestrial radio‐access network. Additionally, we propose necessary improvements to these legacy schemes and explain the necessity of these modifications. The proposed schemes are implemented in the ns‐2 network simulator and are evaluated under various network conditions and topologies. Finally, we measure the performance of the proposed modified schemes and compare them with the corresponding legacy mechanisms. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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OFDM符号是由多个子载波信号叠加而成,为确保各子载波之间的正交性,就对载波间的同步有很严格的要求,否则将造成信道间干扰和符号间干扰,严重影响OFDM系统的性能。提出一种新的基于循环前缀的OFDM时频同步算法,通过仿真,将新算法和传统的ML算法及集相关算法相比较。仿真结果表明,新算法具有更好的频偏和定时估计性能。 相似文献