共查询到18条相似文献,搜索用时 359 毫秒
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针对多小区LTE移动通信系统,考虑用户的最小速率要求,以最大化系统能效为目标,提出了一种迭代式的资源分配算法,通过不断迭代子信道分配和功率控制两个子过程来优化系统能效.针对子信道分配问题,提出了一种基于三种基本模式的子信道调整算法;针对功率控制问题,建立了多小区非合作博弈模型,理论证明了纳什均衡点的存在性,并设计了算法收敛于该纳什均衡点.仿真结果表明,与多小区最大化系统吞吐量算法相比,提出的算法获得了明显的能效增益,同时也达到了较好的系统吞吐量,尤其在强干扰环境下该算法的优势更加明显. 相似文献
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基于正交频分多址(OFDMA)解码-转发中继的系统资源分配方法不能兼顾系统容量与用户公平度。针对该问题,提出一种新的子载波与功率资源分配算法,其中包括子载波分配与配对以及功率分配2个过程。在子载波分配与配对过程中,设计新的同步子载波差值最小配对方法,以最大程度匹配两跳链路配对的子载波。在功率分配过程中,通过拉格朗日方法调整每个子载波对的功率,进一步提高系统传输速率。仿真结果表明,将该策略运用于不同的OFDMA子载波分配算法中能够较好地兼顾系统容量与用户间公平度。 相似文献
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针对多用户OFDMA系统资源分配中已有算法对系统容量和公平性兼顾较差的情况,提出了一种满足比例公平性的系统容量最大化资源分配算法。首先选择合适的公平度门限范围,在子载波分配中,先将各个子载波分配给信道增益最大的用户,再在公平度门限约束下重新分配最大速率用户的信道增益最小的子载波,可以实现子载波利用率和公平度的折中。然后采用注水线法分配功率来调整用户间的比例公平性,最终找到使系统容量最大的公平度门限。仿真结果表明,该算法在保证了用户间比例公平性为1的同时提高了系统容量。 相似文献
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针对多用户多业务基于正交频分多址的电力线通信系统,提出一种在数据链路控制层进行用户调度和在物理层进行资源分配的多层多目标最优的跨层资源分配算法,其用户调度根据所有用户的服务质量(QoS)满意程度、QoS要求、业务包模型、信道状态信息和队列状态信息,从所有用户中选出要服务的用户和确定这些用户的最优跨层参数;其资源分配则根据所有调度用户的QoS要求、最优跨层参数和信道状态信息,先把功率按地窖注水原理分给每个子载波,再把每个子载波最优地分给调度用户并采用逐比特加载查表算法调整其上分配的功率和比特。最后在典型的电力线信道环境下对算法进行仿真,结果表明新算法在系统资源大范围变化时也能保障用户的服务质量,同时有效地提高系统资源的利用。 相似文献
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资源分配是OFDMA系统中保证用户QoS和提高系统容量的一种重要手段.在传统的OFDMA资源分配算法中,分组调度和子载波分配两部分是独立进行优化的.为了进一步提高系统的整体性能,提出一种基于遗传算法的分组调度和子载波分配联合优化的资源分配算法.资源分配算法中,利用随机逼近的方法来更新调度算法中的控制参数,在保证用户公平性的前提下最大化系统吞吐量;利用遗传算法来求解联合优化中的子载波分配.仿真结果表明,无论是在系统的吞吐量、丢包率,数据包等待时延还是用户公平性方面,都具有良好的性能. 相似文献
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在多业务的正交频分多址(OFDMA)蜂窝系统中,为改善小区整体的吞吐量并提高多用户之间传输数据的公平性,提出一种基于最优调度优先级进行资源块分配的长期演进项目(LTE)下行分配方案。打破传统资源分配过程中顺序分配资源的束缚,将用户与资源块(RB)配对,优先把服务质量最好的RB资源分配给相应的用户,尽量保证用户在各自有利的信道上传输数据。仿真结果表明,该方案在不增大丢包率的前提下,有效提高了系统的吞吐量和公平性指数,对LTE下行链路是一个很好的选择。 相似文献
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We consider a cross-layer scheme for the downlink multiuser Orthogonal Frequency Division Multiple Access (OFDMA) for mobile WiMAX (Worldwide Interoperability for Microwave Access) based on IEEE802.16e standard. We propose an intelligent Medium Access Control (MAC) that adapts with the physical layer (PHY) in response to the different QoS requirements of the diverse service flows in the system. This adaptation is represented by a joint packet scheduling and slot allocation scheme interaction in both MAC and PHY layers. Based on this interaction, a fair and efficient QoS guaranteed resource allocation for a mixture of real-time and non real-time service flows is achieved. We provide extensive simulation results showing the performance aspects of the proposed cross-layer scheme. 相似文献
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基于自适应遗传算法的OFDMA系统跨层资源分配问题研究 总被引:1,自引:0,他引:1
OFDMA系统中的跨层资源分配问题是目前的研究热点。本文提出了基于自适应遗传算法的OFDMA系统跨层资源分配算法,利用自适应遗传算法群体多样性的特点提高算法的全局搜索能力,较好地解决了跨层资源分配问题。仿真结果表明,在满足用户间公平性的前提下,本文提出的改进算法有效提高了系统的频谱利用率及吞吐量,减小了用户的平均等待时延,提高服务质量。 相似文献
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在非正交多址接入异构网络中,通过联合资源分配和用户调度可达到用户调度数与系统吞吐量之间的平衡。提出一种基于匹配理论的用户-子信道双边匹配算法(USTSMA)。在满足用户最小数据速率需求和已知完美信道状态信息的条件下,将用户和子信道认为是追求自身最大收益的两个独立集合,通过迭代的方式实现用户和子信道之间的稳定匹配。在此基础上,利用注水算法解决用户的功率分配问题。仿真结果表明,USTSMA在系统总吞吐量、用户调度数等方面性能优于S-MGA和GA两种用户分组算法以及正交频分多址接入方案,并且逼近最优上界。 相似文献
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Orthogonal frequency division multiple-access (OFDMA) manages to efficiently exploit the inherent multi-user diversity of a cellular system by performing dynamic resource allocation. Radio resource allocation is the technique that assigns to each user in the system a subset of the available radio resources (mainly power and bandwidth) according to a certain optimality criterion on the basis of the experienced link quality. In this paper we address the problem of resource allocation in the downlink of a multi-cellular OFDMA system. The allocation problem is formulated with the goal of minimizing the transmitted power subject to individual rate constraint for each user. Exact and heuristic algorithms are proposed for the both the single-cell and the multi-cell scenario. In particular, we show that in the single-cell scenario the allocation problem can be efficiently solved following a network flow approach. In the multi-cell scenario we assume that all cells use the same frequencies and therefore the allocation problem is complicated by the presence of strong multiple access interference. We prove that the problem is strongly NP-hard, and we present an exact approach based on an MILP formulation. We also propose two heuristic algorithms designed to be simple and fast. All algorithms are tested and evaluated through an experimental campaign on simulated instances. Experimental results show that, although suboptimal, a Lagrangian-based heuristic consisting in solving a series of minimum network cost flow problems is attractive for practical implementation, both for the quality of the solutions and for the small computational times. 相似文献
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A multi-user multi-cell Multiple-Input Multiple Output/Orthogonal Frequency Division Multiple Access (MIMO/OFDMA) system for next generation Broadband Wireless Access (BWA) networks is studied, in which the Base Station (BS) or evolved Node B (eNB) has only knowledge of the statistics of the channel. A combination of MIMO and OFDMA could increase the spectral efficiency in a high speed network. We investigate methods with scalable channel feedback and we analyze the trade off between the amount of Channel State Information (CSI) to the transmitter and the system performance. The proposed schemes with limited feedback are combined with other cell interference reduction strategies based on cooperation for improving the performance of a coordinated multi-cell system under very dynamic conditions like high velocity and fast fading. Simulation results demonstrate that substantial gain is obtained by the proposed schemes which take advantage of the statistical information of the highly dynamic channel. 相似文献
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针对放大-转发OFDMA中继系统的多用户比例公平资源分配问题, 在独立功率约束条件下,提出一种联合的子载波和功率分配的调度方案。方案将该资源分配问题的计算转化为对其对偶问题的计算,通过计算对偶问题间接获得原问题的解。对于对偶问题的计算采用次梯度方法。在每次迭代计算过程中,利用Hungarian算法进行最佳的子载波配对,子载波对的用户分配采用比例公平原则,利用改进的注水算法进行功率调整。仿真分析表明,在多用户比例公平的原则下所提方案的频谱效率得到明显提高。 相似文献
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This article treats the resource allocation problem for the downlink of a multi-cell, multiservice Wireless Mobile Communications System (WMCS) with heterogeneous architecture deployed into an urban environment using Long Term Evolution (LTE) and Orthogonal Frequency Division Multiple Access (OFDMA) in its physical level.The optimization model aims to satisfy services to users by making an efficient use of the available resources, and a fair frequency block allocation, using the Signal to Interference-plus-Noise Ratio (SINR). It is a Mixed Integer Nonlinear Programming (MINLP) model whose solution is complex to obtain directly. The proposed solution algorithm decouples the solution space of the problem and uses an iterative and semi-distributed approach to implement a frequency-domain scheduler in the medium term that uses a global vision of the system to allocate resources trying to obtain the SINR required for all users (the proposed goal). Since it is not always possible to achieve it, we take advantage of the elasticity of some of the services offered and incorporate a slack variable to solve it.The approach allows selecting the frequency allocation strategy, the exploration focus of the search space and the system administrator’s vision. The results obtained show that the implementation that uses a coordinated frequency allocation obtains better results in the amount of users with full satisfaction and in the use of power when compared to implementations using other frequency allocation strategies. In scenarios with heterogeneous architecture, the combined effect of picocells and coordinated frequency allocation improves the value for the defined performance metrics. 相似文献
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Zhaoming Lu Yan Yang Xiangming Wen Ying Ju Wei Zheng 《Journal of Network and Computer Applications》2011,34(6):1861-1868
As a new technology, inter-eNB coordination has been included in LTE-Advanced study items. Moreover, the network architecture in LTE-Advanced system is modified to take into account coordinated transmission. In our study, we explore the problem of jointly optimizing the power level and scheduling of resource blocks for LTE-Advanced network based on orthogonal frequency division multiplexing (OFDM). We propose a distributed optimization scheme based on evolutionary potential games, and in the process of objective function modeling we employ the Lagrangian multiplier method to solve the constraint objective optimization problem. Then particle swarm optimization (PSO) method is adopted to find the optimal power allocation and scheduling for each resource block in the multi-cell framework. Numerical results prove that proposed algorithm notably improves the overall throughput, while user fairness is guaranteed. Importantly, additional computation and communication cost introduced by cross-layer optimization is also evaluated. 相似文献