共查询到19条相似文献,搜索用时 673 毫秒
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对全复用多小区系统下行链路用户调度与功率分配问题进行了研究,提出了一种半分布式的用户调度与功率分配方案.首先,各小区根据自身所辖用户的信道与干扰信息,采用最大信干噪比准则进行用户调度,然后各基站将所调度用户的信息上报给中央资源控制器,最后中央资源控制器基于最速下降法的思想,采用贪婪功率分配(GPA)算法为各用户分配相应的发射功率.所提方案利用小区之间的相互协作有效地弱化了小区间干扰,与现有方法相比获得了更好的吞吐量性能和更高的功率效率. 相似文献
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在可用子载波、干扰温度、次级用户功率预算及公平性等约束条件下,提出了一种适用于认知OFDM系统的公平有效的多用户资源分配方案.该方案将子载波和功率分配分为两个相继的步骤,以降低计算复杂度.第一步引入子载波分配的比例公平原则,保证每个用户都能满足一定的通信要求;第二步采用一种改进的快速迭代注水算法,通过选择适当的调整步长... 相似文献
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针对放大转发(AF)的多源多中继两跳协作通信网络模型,提出了一种基于轮询分组调度算法的节点选择与用户调度策略.与之前所提出的中继选择选择算法相比,所提出的中继节点轮询分组调度算法,不需要额外的信令开销,复杂度低,并保证中继间的负载均衡.此外,为保证用户传输的公平性,提出一种结合多用户分集的轮询分组调度算法.最后在已选择的中继节点和所调度的源节点用户中引入分布式空时编码.仿真结果表明,该节点选择和用户调度算法能保证所有节点使用的公平性,并且结合分布式空时编码之后,可以提高频谱利用率,从而提高了系统性能. 相似文献
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针对OFDMA系统多小区上行链路资源分配问题,提出了一种新的基于基站合作(BSC)和软频率复用(SFR)的资源分配方案。该方案通过相邻小区使用不同的子载波的软频率复用减少小区间干扰,利用基站合作对边缘用户的信号重构,使小区间干扰进一步消除,从而将多小区资源分配转化为单一小区资源分配。然后根据选择子载波避免冲突原则进行第一次子载波分配。最后根据速率要求,在不影响其他用户最低速率要求的前提下,对子载波进行二次分配。分析和仿真结果表明,该方案可以很好地解决小区边缘干扰严重的问题,降低用户的中断率,使多小区资源分配更加简单、公平、有效,尤其可保证边缘用户的服务质量,从而改善了系统的性能。 相似文献
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为提高认知无线电网络中主用户和次用户的通信质量,并可简单有效地利用中继节点来控制主用户和次用户之间的相互干扰,提出了一种基于公共中继的最佳中继选择和功率分配方案.首先,在认知无线电网络中建立了基于公共DF中继的无线通信模型;然后,根据无线通信理论推导出要优化的目标函数;最后,在保证主用户中断概率低于目标值的前提下,利用凸优化理论得出了模型中的最佳中继选择和功率分配方案.仿真实验结果表明,与常见的直接传输方案和功率平均分配的中继方案相比,本文提出的中继选择和功率分配方案提高了次用户的通信距离和速率,并且降低了主用户的中断概率,为更好地解决认知无线电网络中主用户和次用户的相互干扰问题提供了新的思路. 相似文献
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研究了干扰链路流量大小对IEEE802.16Mesh网络传输性能的影响,提出了一种通过计算用户站(SS)和基站(BS)的通信路径干扰的总流量来寻找总干扰流量最小的路由算法,并结合路由树给出了一种冲突避免调度的方法。该算法既考虑了干扰链路的数量,又考虑了干扰链路的实际通信强度,在建立路由树的过程中能够更快地使系统达到更佳的负载均衡状态,最大强度地避免调度中可能出现的带宽冲突。由于干扰流量的影响可以得到有效的控制,系统的吞吐量可以明显提高。仿真结果验证了该算法的有效性。 相似文献
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IEEE 802.16j spreads out the coverage of WiMAX networks and strengthens wireless signal transmission using relay technology. To take advantage of relaying in IEEE 802.16j networks, an efficient scheduling schedule with quality of service (QoS) provision for multiple link transmissions is necessary, especially when link interference exists. In this paper, we propose an uplink scheduling mechanism in the transparent mode of IEEE 802.16j, which enables multiple devices to transmit without interference. The maximum latency of each connection has been considered in order to optimize the violation and transmission rate. An interference detection task is first carried out, and then a resource allocation algorithm and a dynamic frame adjustment method are developed. Two simulation experiments were conducted with different interference levels. The results demonstrate that under a fixed QoS type of connection, when the total number of connections goes up to 360 and 420 and the maximum latency violation rate approaches 20%, the average uplink transmission rate of the proposed mechanism can achieve 6.67 and 7.92 Mbps, which apparently outperform regular relay scheduling schemes with rate of 4 and 3.91 Mbps, respectively. 相似文献
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Cross-layer queuing analysis on multihop relaying networks with adaptive modulation and coding 总被引:1,自引:0,他引:1
Multihop relaying is one of the promising techniques in future generation wireless networks. The adaptive modulation and coding (AMC) mechanisms can be applied in order to increase the spectral efficiency of wireless multihop networks. However, most of these mechanisms concentrate on the physical layer without taking the queuing effects at the data link layer into account, whose performances are overestimated. Therefore the cross-layer analytical framework is presented in analysing the quality-of-service (QoS) performances of the decode-and-forward (DF) relaying wireless networks, where the AMC is employed at the physical layer under the conditions of unsaturated traffic and finite-length queue at the data link layer. Considering the characteristics of DF relaying protocol at the physical layer, the authors first propose modelling a two-hop DF relaying wireless channel with AMC as an equivalent Finite State Markov Chain (FSMC) in queuing analysis. Then, the performances in terms of queuing delay, packet loss rate and average throughput are derived. The numerical results show that the proposed analytical method can be efficiently applied for studying the issues including the relay deployment and the cross-layer design in the multihop relaying networks. 相似文献
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Yuan Li Jiaxuan Xie Mu Xia Qianqian Li Meng Li Lei Guo Zhen Zhang 《计算机、材料和连续体(英文)》2021,69(3):3619-3628
The goal of delivering high-quality service has spurred research of 6G satellite communication networks. The limited resource-allocation problem has been addressed by next-generation satellite communication networks, especially multilayer networks with multiple low-Earth-orbit (LEO) and non-low-Earth-orbit (NLEO) satellites. In this study, the resource-allocation problem of a multilayer satellite network consisting of one NLEO and multiple LEO satellites is solved. The NLEO satellite is the authorized user of spectrum resources and the LEO satellites are unauthorized users. The resource allocation and dynamic pricing problems are combined, and a dynamic game-based resource pricing and allocation model is proposed to maximize the market advantage of LEO satellites and reduce interference between LEO and NLEO satellites. In the proposed model, the resource price is formulated as the dynamic state of the LEO satellites, using the resource allocation strategy as the control variable. Based on the proposed dynamic game model, an open-loop Nash equilibrium is analyzed, and an algorithm is proposed for the resource pricing and allocation problem. Numerical simulations validate the model and algorithm. 相似文献
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《Communications, IET》2009,3(1):1-9
The IEEE 802.15.3 medium access control (MAC) protocol is an emerging standard for high-rate wireless personal area networks (WPANs), especially for supporting high-quality real-time multimedia applications. Despite defining quality of service (QoS) signalling mechanisms for interoperability between devices, IEEE 802.15.3 does not specify resource allocation algorithms that are left to manufacturers. To guarantee the QoS of real-time variable bit rate (VBR) videos and utilise the radio resource efficiently, the authors propose a dynamic resource allocation algorithm. The proposed bandwidth allocation algorithm is based on a novel traffic predictor. Recently, the variable step-size normalised least mean square (VSSNLMS) algorithm was employed for on-line traffic prediction of VBR videos. However, the performance of the VSSNLMS algorithm significantly degrades due to the abrupt traffic variation occurring at the scene boundary. To tackle this problem, the authors design a novel traffic predictor based on a simple scene detection algorithm and the VSSNLMS algorithm. Analyses using real-life MPEG video traces indicate that the proposed traffic predictor significantly outperforms the VSSNLMS algorithm with respect to the prediction error. The performance of the proposed bandwidth allocation algorithm is also investigated by comparing several existing algorithms. Simulation results demonstrate that the proposed bandwidth allocation algorithm surpasses other mechanisms in terms of channel utilisation, buffer usage and packet loss rate. 相似文献
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This is the second part of the survey of recent and emerging topics in wireless networking. We provide an overview of the
area of wireless networking as that of dealing with problems of resource allocation so that the various connections that utilise
the network achieve their desired performance objectives.
In Part I we provided a taxonomy of wireless networks as they have been deployed. We then provided a quick survey of the main
issues in the wireless ‘physical’ layer. We then discussed some resource allocation formulations in CDMA (code division multiple
access) cellular networks and OFDMA (orthogonal frequency division multiple access) networks.
In this part we begin with a discussion of random access wireless networks. We first provide an overview of the evolution
of random access networks from Aloha to the currently popular 802·11 (Wi-Fi) networks. We then analyse the performance of
the 802· 11 random access protocol. We briefly discuss the problem of optimal association of nodes to Wi-Fi access points.
Next, we consider topics in ad hoc multihop wireless networks. We first discuss topology and cross layer control. For the
latter, we describe the important maximum weight link scheduling algorithm. The connectivity and capacity of randomly deployed
networks are then analysed. Finally, we provide an overview of the technical issues in the emerging area of wireless sensor
networks. 相似文献
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In this paper, maximizing energy efficiency (EE) through radio resource
allocation for renewable energy powered heterogeneous cellular networks (HetNet) with
energy sharing, is investigated. Our goal is to maximize the network EE, conquer the
instability of renewable energy sources and guarantee the fairness of users during
allocating resources. We define the objective function as a sum weighted EE of all links
in the HetNet. We formulate the resource allocation problem in terms of subcarrier
assignment, power allocation and energy sharing, as a mixed combinatorial and
non-convex optimization problem. We propose an energy efficient resource allocation
scheme, including a centralized resource allocation algorithm for iterative subcarrier
allocation and power allocation in which the power allocation problem is solved by
analytically solving the Karush-Kuhn-Tucker (KKT) conditions of the problem and a
water-filling problem thereafter and a low-complexity distributed resource allocation
algorithm based on reinforcement learning (RL). Our numerical results show that both
centralized and distributed algorithms converge with a few times of iterations. The
numerical results also show that our proposed centralized and distributed resource
allocation algorithms outperform the existing reference algorithms in terms of the
network EE. 相似文献
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The authors consider a dual-hop multi-relay cooperative relay system in this study. Both decode-and-forward (DF) and amplify-and-forward (AF) protocols are considered. Under different relay selection strategies, the authors derive closed-form outage probability expressions. With the second-order channel statistics, the authors propose to jointly optimise power allocation (PA) and relay positions in order to minimise the system outage probability. Simulation results show that the proposed adaptive allocation algorithms significantly outperform fixed allocation algorithms. With the proposed joint optimisation algorithm, AF relaying outperforms DF relaying when multiple relays are selected to help. When only the best relay is selected to help, DF relaying is shown to have better performance. 相似文献
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Azka Amin Xihua Liu Imran Khan Peerapong Uthansakul Masoud Forsat Seyed Sajad Mirjavadi 《计算机、材料和连续体(英文)》2020,65(2):1487-1505
One of the most effective technology for the 5G mobile communications is
Device-to-device (D2D) communication which is also called terminal pass-through
technology. It can directly communicate between devices under the control of a base
station and does not require a base station to forward it. The advantages of applying D2D
communication technology to cellular networks are: It can increase the communication
system capacity, improve the system spectrum efficiency, increase the data transmission
rate, and reduce the base station load. Aiming at the problem of co-channel interference
between the D2D and cellular users, this paper proposes an efficient algorithm for
resource allocation based on the idea of Q-learning, which creates multi-agent learners
from multiple D2D users, and the system throughput is determined from the
corresponding state-learning of the Q value list and the maximum Q action is obtained
through dynamic power for control for D2D users. The mutual interference between the
D2D users and base stations and exact channel state information is not required during
the Q-learning process and symmetric data transmission mechanism is adopted. The
proposed algorithm maximizes the system throughput by controlling the power of D2D
users while guaranteeing the quality-of-service of the cellular users. Simulation results
show that the proposed algorithm effectively improves system performance as compared
with existing algorithms. 相似文献