共查询到20条相似文献,搜索用时 15 毫秒
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In this study, we propose a novel meta-heuristic optimization algorithm for joint peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems. High PAPR not only complicates a distortion of a signal at the nonlinear high-power amplifier of a transmitter the design, but also in significant performance degradation. Tone injection (TI) scheme is a well-known PAPR reduction technique for OFDM systems. The key idea of the proposed method is a distortionless technique that can reduce PAPR significantly without data rate loss and does not require the extra side information. But unfortunately, in optimal TI-based OFDM systems, the PAPR reduction performance mainly requires an exhaustive search over all possible constellations, which is a hard optimization problem and potential problem for practical applications. To address this problem, an efficient scheme based on firefly algorithm is introduced to search over all combinations of possible permutations of the expanded constellation with low complexity and fast convergence. The simulation results reveal that our system can achieve good tradeoff between PAPR reduction performance and low computational complexity. 相似文献
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Power control algorithm based on non-cooperative game theory in successive interference cancellation
Sun Renhao Wei Zhenchun Lyu Zengwei Ding Xu Shi Lei Hu Songhua 《Wireless Networks》2019,25(6):3297-3305
Wireless Networks - Successive interference cancellation (SIC) is an effective way of multi-packet reception to combat interference in wireless networks. The power control problem among wireless... 相似文献
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Co-channel interference cancellation based on MIMO OFDM systems 总被引:6,自引:0,他引:6
Giangaspero L. Agarossi L. Paltenghi G. Okamura S. Okada M. Komaki S. 《Wireless Communications, IEEE》2002,9(6):8-17
This article deals with the exploitation of multiple input multiple output (MIMO) systems for broadband wireless indoor applications. Two systems, the Wind-Flex and ubiquitous antenna, are considered. Both aim to increase the system capacity by different approaches, to increase the single link data rate and the number of users in the whole system, respectively. Computer simulation results show the effectiveness of both MIMO systems. 相似文献
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This letter presents a new soft feedback interference cancellation (SFIC) based equalizer suitable for iterative receivers applying turbo equalization. SFIC offers a very low computational complexity depending only linearly on the channel memory length. Despite its low complexity, SFIC shows a very good BER performance. Simulation results for the severely intersymbol interference distorted Proakis C channel show, that our approach performs within 0.5 dB to the powerful turbo equalization scheme based on MMSE linear filtering with time-varying coefficients and fails the mathematical optimum maximum a-posteriori (MAP) equalizer only by 1.2 dB. 相似文献
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The authors in this article investigated how to cancel multi-user interference with low feedback amount over 3-user multiple input multiple output(MIMO) interference channel using space-time code and precoders. Space-time block code with coding rate 2 was designed, also zero vectors were introduced into each codeword. The multi-user interference is mitigated by pre-coding at the transmitters and nonlinear operation and unidirectional cooperation link at the receivers. Compared with the existing scheme for the same scene, the proposed scheme greatly reduces feedback amount and improves the sum degrees of freedom(DOF). Simulation demonstrates the validity of the proposed scheme. 相似文献
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基于多天线接收的空间分集技术与均衡技术相结合的空间分集均衡算法可以克服衰落带来的不利影响,有效提高通信系统接收端的性能。文中将多天线支路间的合并权值和均衡器的权值统一合并于盲均衡算法中的系数估计,形成一种新的空间分集盲均衡算法,该算法具有较小的实现复杂度和很好的均衡效果。通过仿真实验表明,在误符号率相同的条件下,本文提出的分集均衡算法比单路信号盲均衡算法所需信噪比低1 dB-2 dB。同时分析了多天线接收的支路信号间存在的相位差以及延迟对算法的性能影响。 相似文献
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一种基于二阶统计量的盲均衡算法 总被引:4,自引:0,他引:4
对于多输入多输出(MIMO)信道,使用有色输入的二阶统计量进行盲均衡是一种有效的方法.相对于原有的、基于自相关匹配原理的盲均衡算法,本文给出了一个在时域上不必先知道用户自相关序列值就能实现均衡的条件,并提出了相应的的时域均衡器训练算法,对含白噪声的情况也进行了讨论. 相似文献
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针对MIMO(多输入多输出)通信系统中传统的基于软干扰消除和MMSE(最少均方误差)滤波器的迭代接收方案对信道相关性较敏感的问题。提出了一种基于混合干扰消除(软干扰消除和硬干扰消除)以及MMSE滤波器的检测算法,并引入一个确信机制来控制错误传播问题。仿真结果表明,新算法相比传统的算法在相关信道环境下有明显的性能增益。定性的计算复杂度分析表明新算法在恰当的系统配置下比传统算法具有更低的计算复杂度。 相似文献
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We propose a blind successive interference cancellation receiver for asynchronous direct-sequence code-division multiple-access (DS-CDMA) systems using a maximum mean energy (MME) optimization criterion. The covariance matrix of the received vector is used in conjunction with the MME criterion to realize a blind successive interference canceler that is referred to as the BIC-MME receiver. The receiver executes interference cancellation in a successive manner, starting with the most dominant interference component and successively cancelling the weaker ones. The receiver is compared against various centralized and decentralized receivers, and it is shown to perform well in the presence of estimation errors of the covariance matrix, making it suitable for application in time-varying channels. We also analyze properties of the covariance matrix estimates which are relevant to the performance of the BIC-MME receiver. Further, the BIC-MME receiver is particularly efficient in the presence of a few strong interferers as may be the case in the downlink of DS-CDMA systems where intracell user transmissions are orthogonal. An iterative implementation that results in reduced complexity is also studied 相似文献
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Jong-Ho Lee Seong-Cheol Kim 《Communications Letters, IEEE》2006,10(8):629-631
In this letter, we propose an efficient detection scheme for space-time block coded (STBC) orthogonal frequency-division multiplexing (OFDM) with insufficient cyclic prefix (CP). The proposed scheme employs successive interference cancellation (SIC) and cyclic prefix reconstruction (CPR) concepts. Simulation results present that the proposed scheme outperforms the conventional scheme for STBC OFDM systems. 相似文献
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An adaptive equalization and interference cancellation method is proposed. The proposed scheme can cancel both intersymbol interference and cochannel interference, and is blind in the sense that no knowledge of the training sequences of the interfering users is required. In particular, it is a maximum likelihood sequence estimation (MLSE) equalizer that is implemented by the generalized Viterbi algorithm (GVA) with an RLS-based channel estimator. To demonstrate the potential of the proposed method, various simulation results over a frequency selective Rayleigh fading environment in the presence of cochannel interference are presented. In addition, a sequential algorithm is introduced to reduce the computational complexity of GVA 相似文献
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Il-Min Kim 《Communications, IEEE Transactions on》2004,52(7):1204-1213
Based on a zero-forcing with successive interference cancellation (ZFSIC) method, we construct variable-rate space-time block codes (STBCs) for two, three, and four transmit antennas in Rayleigh fading channels. Considering the error-propagation effect in the ZFSIC scheme, we analyze the bit-error rate (BER) and optimize the transmit power so that the average BER is minimized. Unlike the approach based on zero-forcing (ZF), the method adopted in this paper can construct variable-rate STBCs even when the receive antennas are fewer than the transmit antennas. In addition, to improve the BERs further, we propose space-time power optimization. Numerical results show that the codes presented in this paper provide much lower BERs, compared with the codes developed by Kim and Tarokh. 相似文献
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研究了常数模算法、多模算法、加权多模算法,并分析了各个算法的优缺点。针对加权多模盲均衡算法稳态误差小,但收敛速度慢的缺点,提出了一种基于切换步长的加权多模算法,最后对各算法在复信道环境下进行了仿真。结果表明,改进算法不受相位偏移的影响,而且在稳态误差基本不变的情况下,加快收敛速度。 相似文献
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For singular value decomposition (SVD)-based multiple input multiple output (MIMO) systems, implicit channel state information (CSI) incurs interferences amongst sub-channels if the CSI at the transmitter is not explicit.An improved SVD-based MIMO which can fully cancel the inter sub-channel interferences by reconstructing the transmitter- receiver system matrix on interferences analysis is provided.Simulation results indicate that the proposed algorithm outperforms the traditional SVD-based MIMO in a large degree. 相似文献