共查询到17条相似文献,搜索用时 93 毫秒
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一种多用户MIMO-OFDM系统中的天线与子载波分配算法 总被引:1,自引:0,他引:1
天线与子载波分配是多用户MIMO-OFDM系统无线资源管理中的重要内容.在分析了多用户MIMO-OFDM系统下行链路中最优天线与子载波分配算法的基础上,提出了一种次优的低复杂度天线与子载波分配算法.该算法通过先选择天线再选择用户从而避免了最优算法中的遍历搜索.仿真结果表明,在运算量大大降低的情况下,所提算法获得的系统最大容量和最优算法所获得的最大容量相比相差不大,而且空间和频率联合优化的结果使其性能远远优于仅在MIMO环境下进行子载波分配的算法. 相似文献
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研究了DF多跳OFDM通信系统的功率分配优化.在总发射功率受限的条件下,提出了一种双向优化功率分配算法(D-OPA):先优化单个子载波上各中继节点的功率分配,使该子载波上的信道容量最大;再优化各个子载波间的功率分配,使单跳的信道容量最大,从而最大化系统的信道容量.仿真结果表明:提出的算法与自适应功率分配算法、平均功率分配算法相比,信道容量明显提高. 相似文献
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MIMO-OFDM技术 总被引:5,自引:0,他引:5
多进多出(MIMO)系统在发射端和接收端分别设置多副发射天线和接收天线,采用MIMO技术可以提高信道容量和信道可靠性,降低误码率。正交频分复用(OFDM)是一种特殊的多载波传输方案,各子载波在整个符号周期上正交,各子载波信号频谱可以互相重叠,子载波正交复用技术大大减少了保护带宽,提高了频带利用率。MIMO-OFDM技术是OFDM与MIMO技术结合形成的一种新技术,该技术是在OFDM传输系统中采用阵列天线实现空间分集,提高了信号质量。MIMO-OFDM技术将成为下一代移动通信核心技术的解决方案。文中全面介绍了MIMO技术和OFDM技术及两者的结合,分析了实现MIMO-OFDM技术的关键,展望了发展前景。 相似文献
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针对以往文献的不足,该文重新推导了衰落信道下MIMO-OFDM系统信道容量公式,分析了子载波数目、时延扩展、角度扩展以及天线间距等因素对信道容量的影响。理论分析和仿真结果符合MIMO-OFDM信道容量特征。 相似文献
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提出了一种适应多用户MIMO-OFDM下行传输的新型子载波分配算法.该算法根据各个用户的信道特征,将空间维多用户天线组选择手段引入频率维的子载波组分配算法中,从而在不明显降低系统整体性能的前提下大大降低发射端计算复杂度,使之更适用于实时信道传输环境.仿真结果表明,该算法在计算复杂度大幅减小的情况下仍能保证系统性能无明显损失. 相似文献
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Jamal S. Rahhal 《电信纪事》2010,65(7-8):353-358
Orthogonal frequency division multiple-access technique showed a successful utilization of channel features. It implements an orthogonal sub-carrier space to be shared among different users. The management of these sub-carriers in both power and frequency allocation is reflected on the systems performance as better utilization of bandwidth, and hence, better capacity is obtained. Sub-carrier allocation is used to avoid deep fading that might occur at some user’s locations but not at other user’s locations. In this paper, we devise an algorithm based on probabilistic model for sub-carrier allocation to avoid deep fading in some user’s signals. By controlling the sub-carrier allocation for each user, we can create a full rank channel for each user and hence, provide maximum capacity for the system. Simulation results showed that using the devised algorithm will avoid deep fading and utilize the bandwidth up to 40% more than localized allocation strategies. 相似文献
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Broadband MIMO-OFDM wireless communications 总被引:48,自引:0,他引:48
Stuber G.L. Barry J.R. McLaughlin S.W. Ye Li Ingram M.A. Pratt T.G. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2004,92(2):271-294
Orthogonal frequency division multiplexing (OFDM) is a popular method for high data rate wireless transmission. OFDM may be combined with antenna arrays at the transmitter and receiver to increase the diversity gain and/or to enhance the system capacity on time-varying and frequency-selective channels, resulting in a multiple-input multiple-output (MIMO) configuration. The paper explores various physical layer research challenges in MIMO-OFDM system design, including physical channel measurements and modeling, analog beam forming techniques using adaptive antenna arrays, space-time techniques for MIMO-OFDM, error control coding techniques, OFDM preamble and packet design, and signal processing algorithms used to perform time and frequency synchronization, channel estimation, and channel tracking in MIMO-OFDM systems. Finally, the paper considers a software radio implementation of MIMO-OFDM. 相似文献
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本文以IEEE802.22无线广域网标准为基础,研究了认知无线电环境下MIMO-OFDM系统中分布式无线资源管理问题.基于博弈理论分析,文中首先证明了在全局容量最大化的博弈情况下分布式多用户信道功率分配是Supermodular博弈,并给出了相应的分布式多用户信道功率分配算法,并进一步给出了在认知无线电环境下MIMO-OFDM多用户子载波功率分配问题的解决方法.仿真结果表明,本文算法通过有限的重复博弈,可以有效的提高网络容量。 相似文献
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Changwoo Seo Sherlie Portugal Saransh Malik Cheolwoo You Taejin Jung Huaping Liu Intae Hwang 《Wireless Personal Communications》2013,68(4):1225-1240
The rapid growth in mobile communication users necessitates the development of reliable communication systems that provide higher data rates. To meet these requirements, techniques such as multiple input multiple output (MIMO) and orthogonal frequency division multiplexing (OFDM) have been developed in recent years. Current research activity is focused on developing MIMO-OFDM systems that combine the benefits of both techniques. In addition, for a fast wireless channel environment, the data rate and reliability can be optimized by setting the modulation and coding adaptively according to the channel conditions, as well as by using sub-carrier frequency and power allocation techniques. The overall system performance depends on how accurately the feedback-based system obtains the channel state information and feeds it back to the transmitter without delay. In this paper, we propose a signal-to-noise ratio (SNR) estimation algorithm in which the preamble is known for both sides of the transceiver. Also, we applied AMC on several channel environments using the parameters of IEEE 802.11n and compared throughput performance using each of the different SNR Estimation Algorithm. The results obtained prove that our proposed algorithm is more accurate than traditional algorithms. 相似文献
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David William Marques Guerra Rafael Masashi Fukuda Ricardo Tadashi Kobayashi Taufik Abrão 《ETRI Journal》2018,40(5):570-581
This work analyzes the performance of implementable detectors for the multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) technique under specific and realistic operation system conditions, including antenna correlation and array configuration. A time-domain channel model was used to evaluate the system performance under realistic communication channel and system scenarios, including different channel correlation, modulation order, and antenna array configurations. Several MIMO-OFDM detectors were analyzed for the purpose of achieving high performance combined with high capacity systems and manageable computational complexity. Numerical Monte Carlo simulations demonstrate the channel selectivity effect, while the impact of the number of antennas, adoption of linear against heuristic-based detection schemes, and the spatial correlation effect under linear and planar antenna arrays are analyzed in the MIMO-OFDM context. 相似文献