共查询到20条相似文献,搜索用时 46 毫秒
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本文提出一种利用惩罚函数的分布式波束成形迭代算法,该算法利用当效用函数的梯度为零时的局部最大值的性质。建议算法的收敛性已被证明。仿真结果表明,对比传统算法,建议算法在抑制小区内和小区间干扰方面具有较好的性能,特别是当用户数增加时建议算法具有更高的速率。 相似文献
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徐卫 《中国电子科学研究院学报》2006,1(1):98-101
研究了智能天线在下行链路的应用。利用上行链路接收数据,建立分布式目标信道模型。估计移动用户的发射角、扩展角度和发射功率以及下行信道相关矩阵,确定下行链路的波束形成方法。即对频分复用(FDD)系统进行上行相关矩阵变换,构建下行信道协方差矩阵,利用最大合并比准则获得下行链路权值。计算机仿真证实了这种方法的有效性。 相似文献
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为了克服多小区的邻小区干扰问题,该文在多小区蜂窝网络中,研究了多小区多用户下行协同传输技术。该文提出一种联合优化基站和中继的波束成形权重的迭代算法,在基站和中继总功率限制下最大化最差用户接收信干噪比(Signal-to-Interference-and-Noise Ratio, SINR)。该文提出的联合优化波束成形策略,可以应用半正定松弛技术(Semi-Definite Relaxation, SDR)得到有效的解决。仿真表明,在多小区通信系统中,该文提出的迭代算法只需要少量的迭代次数就可以达到近似最优性能,并且在性能和资源消耗之间给出一种折中的传输策略。 相似文献
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针对大规模多输入单输出的多点协作下行系统,本文主要研究协同波束成形和功率控制,以达到最大化最差用户信干噪比的目的。为了求解原始下行的非凸优化问题,首先将原始优化问题转化成等价的上行优化问题进行求解。尽管在有限系统里可通过迭代算法获得波束矢量和发射功率,但是该算法依赖于瞬时信道信息,功率也需要瞬时更新。为了减少功率更新计算复杂度,本文进一步利用随机矩阵理论,提出了只需要依赖统计信道信息的算法来获得发射功率。数值仿真验证了单基站功率约束下所提算法的有效性以及相对于最大比发送算法的优越性。 相似文献
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A distributed energy efficient beamforming algorithm was studied for multicell multiuser downlink communication system.Firstly,the energy efficient optimization problem was first considered as the maximization of the ratio between the system sum rate and the system power consumption.The fractional programming optimization target was then transformed into a subtractive form via using the fractional programming theorem.Secondly,the problem was decomposed into some subproblems that can be solved respectively by introducing the concept of the interference temperature in cognitive radio networks.Finally,an effective distributed energy efficient beamforming algorithm was proposed by exploiting the Lagrangian duality theorem and optimization theorem.Compared to the classical energy efficient optimization algorithm,the proposed algorithm can achieve an obvious energy efficiency performance gain. 相似文献
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In view of multicell downlink time division multiplexing (TDD) massive multiple-input multiple-output (MIMO) systems which had imperfect channel state information (CSI),the beamforming problem that minimized the total transmit power and signal leakage power based on quality of service (QoS) was studied.First,the objective problem was approximated as a standard convex optimization problem.Then,by using the duality of uplink and downlink,an inner and outer layer iterative algorithm was proposed.Numerical results show that,comparing with other typical downlink multicell massive MIMO beamforming algorithms,the proposed algorithm has obvious advantages in terms of complexity and energy efficiency. 相似文献
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Cheolwoo You Young‐Ho Jung Sunghyun Cho 《International Journal of Communication Systems》2014,27(12):3971-3979
Recently, multiple cell types with overlapping coverage have been deployed simultaneously to increase cellular network capacity. Cross‐tier interference is one of the key technical challenges in the use of this method. A simple and practical beamforming scheme assisted by locally positioned communication devices for the downlink of a multi‐cell wireless hierarchical cell structure system is proposed in this paper to maximize the capacity of the embedded small cell and simultaneously ensure minimal impact on the performance of existing macrocells. The locally positioned communication devices can be implemented with low complexity and at low cost and can continuously provide helpful and accurate information to base stations for the proper configuration of geographical cell coverage, allowing neighboring cells to cooperate effectively with each other. Simulation results verify that the proposed scheme can provide a significant gain over conventional systems not using the proposed algorithm. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Distributed beamforming with one-bit feedback and clustering for multi-node wireless energy transfer
Jonghyeok Lee SeongJun Hwang Yong-gi Hong Jaehyun Park Woo-Jin Byun 《ETRI Journal》2021,43(2):221-231
To resolve energy depletion issues in massive Internet of Things sensor networks, we developed a set of distributed energy beamforming methods with one-bit feedback and clustering for multi-node wireless energy transfer, where multiple single-antenna distributed energy transmitters (Txs) transfer their energy to multiple nodes wirelessly. Unlike previous works focusing on distributed information beamforming using a single energy receiver (Rx) node, we developed a distributed energy beamforming method for multiple Rx nodes. Additionally, we propose two clustering methods in which each Tx node chooses a suitable Rx node. Furthermore, we propose a fast distributed beamforming method based on Tx sub-clustering. Through computer simulations, we demonstrate that the proposed distributed beamforming method makes it possible to transfer wireless energy to massive numbers of sensors effectively and rapidly with small implementation complexity. We also analyze the energy harvesting outage probability of the proposed beamforming method, which provides insights into the design of wireless energy transfer networks with distributed beamforming. 相似文献
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为了能够减少多小区基站协作时的回传开销和预编码复杂度,研究了基于信漏噪比(SLNR)最大化准则的协作多小区传输分布式预编码算法。多个小区协作传输数据,仅仅需要局部的信道状态信息和用户的数据信息,减少了无线回传开销,得到基站协作带来的性能提高。仿真表明,与协作多小区传输的迫零(ZF)算法和协作单小区传输的SLNR算法相比,协作多小区传输SLNR预编码在开销和性能之间取得了良好的折衷。 相似文献
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A single transmission selection scheme for downlink distributed antenna system in multicell environment 下载免费PDF全文
Yuxi Liu Ju Liu Weidong Guo Lina Zheng Peng Chen 《International Journal of Communication Systems》2014,27(12):3748-3758
In this paper, based on maximum signal‐to‐interference‐plus‐noise ratio criterion at the receiver, we propose a single transmission selection scheme for distributed antenna system and investigate the corresponding ergodic capacity together with outage probability in multicell environment. Assuming that the channels suffer from independent non‐identical Nakagami‐m fading with integer values of fading severity parameter m, we derive exact closed‐form expressions for the ergodic capacity and outage probability. Monte‐Carlo simulations are carried out to validate the theoretical analysis. Simulation results show that the ergodic capacity and outage probability of the proposed single transmission selection scheme outperform that of blanket transmission scheme. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Multi-cell processing (MCP) is capable of providing significant performance gain, but this improvement is accompanied by dramatic signaling overhead between cooperative base stations. Therefore, balancing the performance gain and overhead growth is crucial for a practical multi-base cooperation scheme. In this paper, we propose a decentralized algorithm to jointly optimize the power allocation and beamforming vector with the goal of maximizing the system performance under the constraint of limited overhead signal and backhaul link capacity. In particular, combined with calculating the transmission beamforming vector according to the local channel state information, an adaptive power allocation is presented based on the result of sum capacity estimation. Furthermore, by utilizing the concept of cell clustering, the proposed framework can be implemented in a practical cellular system without major modification of network architecture. Simulation results demonstrate that the proposed scheme improves the system performance in terms of the sum capacity and cell-edge capacity. 相似文献
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以低轨卫星通信系统能量效率最大化为优化目标,重点研究鲁棒波束成形设计。假设卫星侧配备大规模多输入多输出技术,综合考虑传播延迟和多普勒频移造成的信道状态信息误差影响,在发射功率受限和用户服务质量约束下,提出了一种鲁棒高效的波束成形方案。考虑到遍历用户速率和遍历信干噪比都没有闭合表达式,采用具备闭合表达式的近似值代替,同时,采用半正定规划算法将非凸二次约束二次规划形式问题进行等价转换,并提出了一种联合二次变换分式规划和凹凸过程的内外两层嵌套迭代算法。最后,采用一种惩罚函数算法解决半正定规划算法中存在的秩1约束问题。仿真结果表明,所提算法性能优于传统算法,且鲁棒性较高。 相似文献