A pilot allocation(PA) scheme is propose to reduce pilot contamination for time division duplex(TDD) massive multiple-input multiple-output(MIMO) system enabled twotier heterogeneous cellular network(Het Net). In orde...
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ISBN:
(纸本)9781509038237;9781509038220
A pilot allocation(PA) scheme is propose to reduce pilot contamination for time division duplex(TDD) massive multiple-input multiple-output(MIMO) system enabled twotier heterogeneous cellular network(Het Net). In order to reduce inter-tier interference during channel estimation, proposed scheme assigns mutually orthogonal pilots between macro-cells and small-cells, and pilots are reused among macro-cells with different pilot reuse factors. Comprehensive analyses and simulations of uplink average signal to interference plus noise ratio(SINR) and average achievable ergodic rate for the proposed scheme are developed. Simulation results show that the proposed PA scheme can reduce pilot contamination and improve the SINR and ergodic rate at base stations(BSs). In addition, the average SINR increases when pilot reuse factor grows, which shows the benefit of the proposed scheme. The average ergodic rate first becomes larger and then becomes smaller when pilot reuse factor becomes larger, which means the large number of pilot symbols limits the increase of ergodic rate.
This paper proposes and designs a microstrip antenna that can work in the B1 band for Beidou with a double-layer substrate, and realizes the circularly polarized radiation characteristics. The antenna consists of a gr...
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Magnetic coupling resonance wireless power transmission is a new technology to realize the wireless transmission of energy by means of high frequency coupling resonance between the coils. The variation of the coupling...
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The paper introduces a Kernel Weibull M-Transform Least-Mean Square (LMS) (KWMLMS) algorithm aimed to enhance filtering performance for a nonlinear system. By incorporating the Weibull M-Transformation into the cost f...
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Community structure is one of the most important features in real networks and reveals the internal organization of the vertices. Uncovering accurate community structure is effective for understanding and exploiting n...
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Community structure is one of the most important features in real networks and reveals the internal organization of the vertices. Uncovering accurate community structure is effective for understanding and exploiting networks. Tolerance Granulation based Community Detection Algorithm(TGCDA) is proposed in this paper, which uses tolerance relation(namely tolerance granulation) to granulate a network hierarchically. Firstly, TGCDA relies on the tolerance relation among vertices to form an initial granule set. Then granules in this set which satisfied granulation coefficient are hierarchically merged by tolerance granulation operation. The process is finished till the granule set includes one granule. Finally, select a granule set with maximum granulation criterion to handle overlapping vertices among some granules. The overlapping vertices are merged into corresponding granules based on their degrees of affiliation to realize the community partition of complex networks. The final granules are regarded as communities so that the granulation for a network is actually the community partition of the *** on several datasets show our algorithm is effective and it can identify the community structure more accurately. On real world networks, TGCDA achieves Normalized Mutual Information(NMI) accuracy 17.55% higher than NFA averagely and on synthetic random networks, the NMI accuracy is also improved. For some networks which have a clear community structure, TGCDA is more effective and can detect more accurate community structure than other algorithms.
Dynamic Quality of Service(QoS)prediction for services is currently a hot topic and a challenge for research in the fields of service recommendation and *** paper addresses the problem with a Time-aWare service Qualit...
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Dynamic Quality of Service(QoS)prediction for services is currently a hot topic and a challenge for research in the fields of service recommendation and *** paper addresses the problem with a Time-aWare service Quality Prediction method(named TWQP),a two-phase approach with one phase based on historical time slices and one on the current time *** the first phase,if the user had invoked the service in a previous time slice,the QoS value for the user calling the service on the next time slice is predicted on the basis of the historical QoS data;if the user had not invoked the service in a previous time slice,then the Covering Algorithm(CA)is applied to predict the missing *** the second phase,we predict the missing values for the current time slice according to the results of the previous phase.A large number of experiments on a real-world dataset,WS-Dream,show that,when compared with the classical QoS prediction algorithms,our proposed method greatly improves the prediction accuracy.
The asymptotic waveform evaluation (AWE) technique combined with the method of moments (MOM) is often applied to accelerate the calculation of the wide-band radar cross section (RCS) of the target. However, the techni...
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This paper designs a broadband circularly polarized antenna covering the 25 GHz to 31 GHz band. The Vivaldi antenna is used as the basic structure to generate broadband electromagnetic waves;circular polarization is a...
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Analysis of electromagnetic scattering characteristics from wire antennas using method of moments has been performed over the past decades. In this paper, an efficient technique is adopted to evaluate the potential an...
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