共查询到18条相似文献,搜索用时 203 毫秒
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接纳控制是为保证服务质量而采取的一种预防性负载控制机制,将其引入无源光网络(PON),在传统的接纳控制算法基础上提出支持用户服务等级协议(SLA)的接纳控制方法,将系统资源划分为不同类别,保证不同等级用户的接入请求.具体分析并验证了该方法可提高高级别用户接入请求的性能. 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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异构网络中的联合会话接纳控制算法就是负责处理新来到的或是切换的会话呼叫请求,根据网络性能、业务类型或是用户偏好等策略,决定会话被哪个RAT(无线接入技术)所接纳。文章介绍了联合会话接纳控制的概念以及主要功能,重点总结了几种主流的联合会话接纳控制算法,并且简要分析了各种算法的优缺点。 相似文献
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异构无线网络中基于马尔可夫决策过程的区分业务接纳控制的研究 总被引:2,自引:0,他引:2
对异构无线网络中区分业务类型的接纳控制机制进行研究.分析了语音和数据2种典型业务在CDMA蜂窝网络和WLAN中的容量区域.基于马尔可夫决策过程理论,提出异构无线网络中区分业务类型的接纳控制理论模型,规定了不同类型业务的接纳控制行为并推导了系统状态转移概率.而且,进一步从用户角度对不同类型业务QoS要求和网络状态之间关系进行分析,提出一种基于模糊逻辑的接纳效用评估机制,在保证各类业务接入和切换成功率的基础上,推导出接纳效用最大的最优接纳控制策略.仿真表明,基于模糊逻辑的接纳效用评估能够有效反映网络状态动态变化对接纳控制的影响,最优接纳控制策略在平均接纳效用方面明显优于不考虑业务区分和用户移动性2种接纳控制机制,并且能严格保证各类业务的接入和切换成功率. 相似文献
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提出了一种在CDMA系统中基于多小区负荷因子增长估计的上行接纳控制算法。在新呼叫到达时,不仅考虑接纳小区的负荷因子增长,同时考虑相邻小区的负荷因子增长,通过理论分析给出了相邻小区负荷因子增长估计的方法。仿真结果表明,基于多小区负荷因子增长估计的接纳控制算法比基于单小区的接纳控制算法能更有效地提高判决精度,降低错误接纳概率和中断概率,保证已连接用户的QoS要求。 相似文献
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TD-SCDMA中基于实测功率的上行接纳算法 总被引:1,自引:0,他引:1
第三代移动通信系统TD-SCDMA是一种自干扰的系统,随着未来用户的增多,无线资源相对有限的情况下,有效控制干扰的要求越来越高,而呼叫接纳控制技术就是解决这一问题的关键技术之一。对传统的接纳控制算法进行研究,提出了基于实测功率的上行接纳控制算法,并计算出接入判决的门限值,以实现用户接入系统后对QoS的保证。实验表明该算法相对于传统的算法而言,判决精度更高,并且具有门限自适应的优势。 相似文献
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针对卫星认知无线网络频谱感知不确定性较大导致传统频谱接入机制效率降低的问题,该文提出一种基于动态多频谱感知的信道接入优化策略。认知LEO卫星根据频谱检测概率与授权用户干扰门限之间的关系,实时调整不同频谱感知结果下的信道接入概率。在此基础上以系统吞吐量最大化为目标,设计了一种基于频谱检测概率和虚警概率联合优化的判决门限选取策略,并推导了最佳感知频谱数量。仿真结果表明,认知用户能够在不大于授权用户最大干扰门限的前提下,根据授权信道空闲状态动态选择最佳频谱感知策略,且在检测信号信噪比较低时以更加积极的方式接入授权频谱,降低了频谱感知不确定性对信道接入效率的影响,提高了认知系统吞吐量。 相似文献
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An access control engine with dynamic priority resource allocation (ACE-DPRA) is proposed for unlicensed users to utilize free spectrum of wireless communication systems. A cognitive radio (CR) network with sensing and learning abilities is essential for unlicensed users to achieve ACE-DPRA. Three algorithms are included in ACE-DPRA to improve the spectral efficiency. While requesting to set up connection, unlicensed CR users generate excessive interferences to licensed users. The proposed ACE-DPRA with an admission control scheme allows the connection of unlicensed CR users without degrading the communication quality of licensed users. The priority algorithm for utilizing the unused spectrum is designed according to the location information of unlicensed users. A transmitted power control method is achieved by a fuzzy-learning mechanism. The spectral efficiency of wireless communication systems can be increased after adopting the proposed ACE-DPRA algorithm. Simulation results show that licensed users keep the advantages of high transmission data rate, low interference power, and low average outage probability after the connection of unlicensed CR users. 相似文献
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A load-transfer-based joint admission control (LJAC) algorithm in heterogeneous networks was proposed.The access requirements of users were admitted based on load balancing,the dynamic load transfer of traffics in the overlapping coverage areas of heterogeneous networks were introduced,and the influence of such factors as the layout of heterogeneous networks and the vertical handoff was considered in the algorithm.The integrated system of heterogeneous networks was modeled as a multidimensional Markov chain,the steady-state probabilities were obtained and the quality of service (QoS) performance metrics were derived.Based on the Poisson point process theory,the upper bound of capacity of the heterogeneous networks satisfying QoS limitations was obtained.The admission control parameters of the integrated system of heterogeneous networks were optimized in order to maximize the resource utilization rate as well as guaranteeing the QoS of users.The simulation results demonstrate lower traffic blocking probability,lower failure probability of vertical handoff requirements,and larger system capacity gain can be achieved by using the proposed LJAC algorithm. 相似文献
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针对全双工无线接入与回传一体化小基站场景下长期的频谱效率和能效同时最大化问题,该文提出一种基于近似动态规划理论的接入与回传一体化小基站接入控制与资源分配联合优化算法。该算法首先联合考虑当前基站的资源使用和功率配置情况,在任一用户需求动态到达以及平均时延、小基站回传速率和传输功率约束下,使用受限马尔科夫决策过程(CMDP)建立频谱效率最大化和功率消耗最小化的多目标优化模型,其次运用切比雪夫理论将多目标优化问题转化为单目标问题,并使用拉格朗日对偶分解法进一步转化为非受限的马尔科夫决策过程(MDP)问题。最后,为了解决其求解时存在的“维度灾”爆炸问题,该文提出基于近似动态规划的无线接入与回传一体化小基站资源动态分配算法进行求解,得到此时的接入与资源分配策略。仿真结果表明,所提算法能在保证平均时延约束、小基站回传速率约束和传输功率约束的同时最大化长期平均频谱效率和能效。 相似文献
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Mobile Edge Computing (MEC) has been envisioned as an efficient solution to provide computation-intensive yet latency-sensitive services for wireless devices. In this paper, we investigate the optimal dynamic spectrum allocation-assisted multiuser computation offloading in MEC for overall latency minimization. Specifically, we first focus on a static multiuser computation offloading scenario and jointly optimize users' offloading decisions, transmission durations, and Edge Servers' (ESs) resource allocations. Owing to the nonconvexity of our joint optimization problem, we identify its layered structure and decompose it into two problems: a subproblem and a top problem. For the subproblem, we propose a bisection search-based algorithm to efficiently find the optimal users' offloading decisions and ESs’ resource allocations under a given transmission duration. Second, we use a linear search-based algorithm for solving the top problem to obtain the optimal transmission duration based on the result of the subproblem. Further, after solving the static scenario, we consider a dynamic scenario of multiuser computation offloading with time-varying channels and workload. To efficiently address this dynamic scenario, we propose a deep reinforcement learning-based online algorithm to determine the near-optimal transmission duration in a real-time manner. Numerical results are provided to validate our proposed algorithms for minimizing the overall latency in both static and dynamic offloading scenarios. We also demonstrate the advantages of our proposed algorithms compared to the conventional multiuser computation offloading schemes. 相似文献