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综合业务CDMA系统的联合呼叫接入-拥塞控制 总被引:3,自引:0,他引:3
本文提出一种新的综合业务控制方案“联合呼叫接入-拥塞控制”,在保证话音业务质量的前提下最大化综合业务CDMA系统的数据吞吐量,使系统充分利用无线信道资源.文章同时提出一种简单的系统参数设计方法,可用于未来综合业务的蜂窝小区规划. 相似文献
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针对 CDMA蜂窝系统区间业务不平衡的情况 ,文中提出了一种呼叫接入控制方案 ,在重负荷小区为邻区即将到来的呼叫预留部分资源 ,预留的大小随呼叫阻塞情况自适应地调整。仿真结果显示 :该方案能很好地解决区间业务不平衡的问题 ,而且与基于固定资源预留的呼叫接入控制方案相比 ,还能获得低的系统呼叫阻塞率 相似文献
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在认知无线电系统中,认知用户利用授权用户的频谱空洞进行通信,达到提高频谱利用率的目的。动态频谱接入技术是认知无线电系统的关键技术,在文中我们提出了一种使用呼叫接纳控制(CAC)的动态频谱接入机制,经过仿真验证该机制能有效地减小认知无线电系统中认知用户的切换概率,同时次用户对信道的使用率会略有下降。 相似文献
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在对移动系统的性能分析中,为了便于分析,通常都没有区分一个小区中切换呼叫和新 呼叫,而是假定它们的信道占用时间具有相同的分布。但在有些实际的系统中,这种假设是不合理的, 两者信道占用时间的均值往往是不同的。设计了一种适用于多业务的呼叫接入控制算法,它对语音业 务基于保护信道法而对语音和数据业务之间采取可移动边界法,并对其性能进行了分析,结果表明切换 呼叫和新呼叫的均值对语音业务和数据业务的性能都具有重要的影响。 相似文献
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基于多种业务流资源共享的在线呼叫接入控制算法 总被引:5,自引:0,他引:5
本文针对多种业务类型提出了一种在线呼叫接入控制算法(OCAC)。OCAC算法是基于QoS业务量的服务质量要求和BE业务量的拥塞状态来动态地调整资源的分配,目的是更有效地利用资源并且在QoS业务流调整服务质量的同时,改善BE业务量的吞吐量。针对多跳的情况,本文描述了OCAC算法的两种实现方案,即基于每个节点和基于源节点的OCAC实现方案(ENS和SNS)。最后给出了仿真结果,并对本文提出的算法和静态接入控制算法的仿真结果进行了比较,进一步说明OCAC算法的有效性。 相似文献
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无线移动通信系统中的呼叫接入控制 总被引:7,自引:0,他引:7
呼叫接入控制是无线移动通信系统中无线资源管理的重要部分,它直接关系到系统中用户服务质量是否能够得到保证,同时呼叫接入控制算法的有效性决定了系统资源的利用效率。文中综述了各种呼叫接入控制算法及其特点,并指出在无线移动通信系统中它们的重要性。 相似文献
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Optimal Joint Session Admission Control in Integrated WLAN and CDMA Cellular Networks with Vertical Handoff 总被引:3,自引:0,他引:3
This paper considers optimizing the utilization of radio resources in a heterogeneous integrated system consisting of two different networks: a wireless local area network (WLAN) and a wideband code division multiple access (CDMA) network. We propose a joint session admission control scheme for multimedia traffic that maximizes overall network revenue with quality of service (QoS) constraints over both the WLAN and the CDMA cellular networks. The WLAN operates under the IEEE 802.11e medium access control (MAC) protocol, which supports QoS for multimedia traffic. A novel concept of effective bandwidth is used in the CDMA network to derive the unified radio resource usage, taking into account both physical layer linear minimum mean square error (LMMSE) receivers and characteristics of the packet traffic. Numerical examples illustrate that the network revenue earned in the proposed joint admission control scheme is significantly larger than that when the individual networks are optimized independently with no vertical handoff between them. The revenue gain is also significant over the scheme in which vertical handoff is supported, but admission control is not done jointly. Furthermore, we show that the optimal joint admission control policy is a randomized policy, i.e., sessions are admitted to the system with probabilities in some states 相似文献
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In this paper, we show how online management of both quality of service (QoS) and provider revenue can be performed in CDMA cellular networks by adaptive control of system parameters to changing traffic conditions. The key contribution is the introduction of a novel call admission control and bandwidth degradation scheme for real-time traffic as well as the development of a Markov model for the admission controller. This Markov model incorporates important features of 3G cellular networks, such as CDMA intra- and inter-cell interference, different call priorities and soft handover. From the results of the Markov model the threshold for maximal call degradation is periodically adjusted according to the currently measured traffic in the radio access network. As a consequence, QoS and revenue measures can be optimized with respect to a predefined goal. To illustrate the effectiveness of the proposed QoS/revenue management approach, we present quantitative results for the Markov model and a comprehensive simulation study considering a half-day window of a daily usage pattern. 相似文献
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为了在802.11的网络中提供服务质量(QoS)支持,IEEE 802.11 Task Group E提出了EDCF协议.然而EDCF只能提供业务区分服务,并不能提供服务质量(QoS)保证.为了能在重负载下提供QoS保证,在WLAN中加入呼叫接纳控制(CAC)机制是非常必要的.本文首先提出了一个新的3维Markov模型对非饱和状态下EDCF的吞吐量和平均接入时延进行了分析.并在此基础上,提出了一种基于效用函数的CAC策略,它可以使网络的总收益达到最大.最后通过大量仿真验证了所提出的CAC策略的有效性. 相似文献
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Improving Voice and Data Services in Cellular/WLAN Integrated Networks by Admission Control 总被引:1,自引:0,他引:1
Wei Song Yu Cheng Weihua Zhuang 《Wireless Communications, IEEE Transactions on》2007,6(11):4025-4037
In this paper, we study voice and data service provisioning in an integrated system of cellular and wireless local area networks (WLANs). With the ubiquitous coverage of the cellular network and the disjoint deployment of WLANs in hot-spot areas, the integrated system has a two-tier overlaying structure. As an essential resource allocation aspect, admission control can be used to properly admit voice and data calls to the overlaying cells and WLANs. A simple admission scheme is proposed in this study to analyze the dependence of resource utilization and the impact of user mobility and traffic characteristics on admission parameters. Both admission control and rate control are considered to limit the input traffic to the WLAN, so that the WLAN operates in its most efficient states and effectively complements the cellular network. The call blocking/dropping probabilities and data call throughput are evaluated for effective and accurate derivation of the admission parameters. It is observed that the utilization varies with the configuration of admission parameters, which properly distributes the voice and data traffic load to the cells and WLANs. Mobility and traffic variability have a significant impact on the selection of the admission parameters. 相似文献
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为了保证干扰受限多业务CDMA移动通信系统工作稳定可靠,必须有效、快速、准确地控制接入系统中的各类业务的用户数目,这一任务由呼叫准入控制(CAC)算法来完成.本文提出的基于门限比较的快速自适应CAC (FACAC)算法与传统的同类算法相比,具有判决速度快、判决精度高、门限自适应和简单易行等特点.仿真结果验证了理论推导的正确性,表明FACAC算法的中断特性优于传统CAC算法60%以上,系统服务等级(GoS)优23%左右(系统业务负荷较高时). 相似文献
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Spectral efficiency of WCDMA based spread spectrum 3G/4G air interface technology is highly influenced by the common channel interference, hence the applied Call Admission Control method has great importance because it determines the number of active users admitted to the network. In this paper we present a dynamic air interface CAC algorithm which provides efficient usage of radio resources and allows real-time adaptation to the always changing network parameters. Required CAC parameters are derived for generalized multiplicative fading and generalized memory-less traffic sources. In order to validate its capabilities our proposed CAC method was investigated with ON/OFF traffic sources and lognormal fading channels. 相似文献
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In this paper, we develop call admission control algorithms for SIR-based power-controlled DS-CDMA cellular networks. We consider networks that handle both voice and data services. When a new call (or a handoff call) arrives at a base station requesting for admission, our algorithms will calculate the desired power control setpoints for the new call and all existing calls. We will provide necessary and sufficient conditions under which the power control algorithm will have a feasible solution. These conditions are obtained through deriving the inverse of the matrix used in the calculation of power control setpoints. If there is no feasible solution to power control or if the desired power levels to be received at the base station for some calls are larger than the maximum allowable power limits, the admission request will be rejected. Otherwise, the admission request will be granted. When higher priority is desired for handoff calls, we will allow different thresholds (i.e., different maximum allowable power limits) for new calls and handoff calls. We will develop an adaptive algorithm that adjusts these thresholds in real-time as environment changes. The performance of our algorithms will be shown through computer simulation and compared with existing algorithms. 相似文献
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Wireless Personal Communications - Nowadays, users of wireless cellular networks are ever increasing, but wireless link bandwidth is limited. Due to heavy traffic in this network and frequent... 相似文献