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A sub-carrier allocation and power control algorithm for D2D users in OFDM systems

Journal of Computational Information Systems 2014年第14期10卷 6117-6124页

作者： Jing, Wenwen Zhu, Qi Jiangsu Key Lab of Wireless Communications Key Lab on Wideband Wireless Communications and Sensor Network Technology of Ministry of Education Nanjing University of Posts and Telecommunications Nanjing China

A resource allocation algorithm for D2D users which establishes an optimization problem aimed at maximizing D2D users throughput and guaranteeing cellular users QoS is proposed in this paper. To solve the problem there need two steps. First, the sub-carrier allocation process based on balancing the quality of both cellular and D2D users is given, and then the sub-gradient method of power allocation is shown. Simulation results prove that the throughputs of both D2D system and the total system are comparatively improved with the proposed algorithm. © 2014 by Binary Information Press

关键词： Power control

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Joint power allocation and multi-relay selection scheme based on system outage probability

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The Journal of China Universities of Posts and Telecommunications 2014年第5期21卷 9-16,23页

作者： ZHOU Zhi-kang ZHU Qi The Key Wireless Laboratory of Jiangsu Province Nanjing University of Posts and Telecommunications Key Laboratory on Wideband Wireless Communications and Sensor Network Technology of Ministry of Education School of Telecommunication and Information Engineering Nanjing University of Posts and Telecommunications

An amplify-and-forward （AF） based multi-relay network is studied. In order to minimize the system outage probability with a required transmission rate, a joint power allocation （PA） and multi-relay selection scheme is proposed under both total and individual power constraints （TIPC）. In the proposed scheme, the idea of ordering is adopted to avoid exhaustive search without losing much system performance. Besides the channel quantity, the ordering algorithm proposed in this article also takes relays＇ maximal output ability into consideration, which is usually ignored in traditional relay ordering algorithms. In addition, simple power reallocation method is provided to avoid repetitive PA operation during the process of searching all possible relay subsets. By Adopting the idea of ordering and using the proposed power reallocation method lead to remarkable decrease of the computation complexity, making the scheme easier and more feasible to implement in practical communication scenarios. Simulations show that the proposed multi-relay selection scheme provides similar performance compared to the optimal scheme with optimal PA and exhaustive search （OPAES） but with much lower complexity.

关键词： cooperative communication multi-relay selection power allocation outage probability amplify-and-forward

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Optimal Transmission Power in a Nonlinear VLC System

Optimal Transmission Power in a Nonlinear VLC System

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IEEE Global Conference on Signal and Information Processing

作者： Shuang Zhao Sunzeng Cai Kai Kang Hua Qian Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences (CAS) Key Laboratory of Wireless Sensor Network and Communications CAS Shanghai Research Center for Wireless Communications Shanghai 200335 China

ISBN: (纸本)9781479975921

In a visible light communication (VLC) system, the light emitting diode (LED) is nonlinear for large signals, which limits the transmission power, or equivalently the coverage of the VLC system. When the input signal amplitude is large, the nonlinear distortion creates both harmonics and intermodulation distortions, which degrades the transmission error vector magnitude (EVM). To evaluate the impact of nonlinearity on system performance, the signal to noise and distortion ratio (SNDR) can be applied, which is defined as the linear signal power over the thermal noise plus the front end nonlinear distortion. At a given noise level, the optimal system performance can be achieved by maximizing the SNDR, which results in high transmission rate or long transmission range for the VLC system. In this paper, we provide theoretical analysis on the optimization of SNDR with a nonlinear Hammerstein model of LED. Simulation results and lab experiments validate the theoretical analysis.

关键词： nonlinearity light-emitting-diode (LED) SNDR

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Joint power control and access control scheme in two-tier femtocell networks

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Journal of Computational Information Systems 2014年第24期10卷 10665-10674页

作者： Cheng, Yanli Zhu, Qi Key Lab on Wideband Wireless Communications and Sensor Network Technology of Ministry of Education Nanjing University of Posts and Telecommunications Nanjing China Jiangsu Key Lab of Wireless Communications Nanjing University of Posts and Telecommunications Nanjing China

Femtocell networks have greatly improved indoor coverage, while the interference to macrocell and between femtocells has become a severe problem to be settled with the dense deployment of femtocell access points (FAPs). This paper puts forward a scheme to combine power control and access control in femtocell networks. Based on Stackelberg game, this paper takes FAPs as leaders and macrocell users (MUEs) as followers. FAPs firstly make decision of their transmission power, and then MUEs decide which base station to access to accordingly. Simulation results show that this scheme enhances users' average throughput compared with general power control scheme, especially improving MUEs' performance to a large extent.

关键词： Femtocell

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Social-aware file-sharing mechanism for device-to-device communications

Social-aware file-sharing mechanism for device-to-device com...

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International Conference on wireless communications and Signal Processing (WCSP)

作者： Lei Wang Lulu Gao Aiqing Zhang Mingkai Chen National Mobile Communications Research Laboratory Southeast University Nanjing China NUPT Key Lab of Broadband Wireless Communication and Sensor Network Technology China

ISBN: (纸本)9781467376884

Device-to-device (D2D) communication technology can significantly improve energy efficiency and offload base station traffic. It has become a new research focus in next generation mobile communications. In this paper, a file-sharing mechanism based on social networks is proposed for the D2D communication system underlaying cellular networks aiming at improving the users' quality of experience (QoE). In the proposed mechanism, all users are divided into several groups according to the documentation requirements. Then the D2D communication links are built within each group by fully considering the social relationships and trust degrees of users. The target files give priority to be shared through the D2D mode. Theoretical analysis and extensive simulation results show clearly that the social relationships can affect the whole wireless networks significantly. Selecting a user with the largest social degree as a central user can greatly reduce the transmission delay, relieve the heavy burden of base stations and then optimize the overall performance of cellular communication systems.

关键词： Base stations Social network services Delays wireless communication Mobile communication Quality of service

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Interference suppression algorithms for D2D communication underlaying cellular networks

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Journal of Computational Information Systems 2015年第18期11卷 6705-6717页

作者： Huan, Cheng Liu, Chen Fu, Youhua The Key Lab. of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing China National Mobile Communications Research Laboratory Southeast University Nanjing China

In this paper, we investigate the interference scenario where Device-to-Device (D2D) users and the cellular user share the same spectrum resource, and propose two novel interference suppression algorithms for D2D communication. One of the two proposed algorithms is the step-by-step interference suppression algorithm called SISA, and the other one is the joint interference suppression algorithm called JISA. The SISA mainly deals with the cellular interference to the D2D receiver, while the JISA copes with not only the cellular interference but also the noise at the D2D receiver. Both algorithms are designed from the perspective of precoding and decoding. Based on this, we first formulate the interference suppression problem for D2D communication as an optimization problem to maximize the signal-to- interference- plus-noise ratio (SINR) of the D2D receiver, and regard the precoding vector of the D2D transmitter and the decoding vector of the D2D receiver as the optimized variables. Second, we in turn propose the SISA and JISA to solve the optimization problem. Finally, we derive out respective closed-form expressions for optimize variables according to the SISA and JISA. Numerical results show that the two proposed algorithms both enable D2D to achieve significant performance gains over that using the existing schemes in terms of SINR and bit-error rate (BER). © 2015 by Binary Information Press.

关键词： Bit error rate

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MADM and rank similarity-based network selection algorithm in heterogeneous networks

MADM and rank similarity-based network selection algorithm i...

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2nd International Conference on Precision Mechanical Instruments and Measurement technology, ICPMIMT 2014

作者： Zhu, Xue Wen Zhu, Qi Jiangsu Key Lab of Wireless Communications Key Lab on Wideband Wireless Communications and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Jiangsu Nanjing 210003 China

ISBN: (纸本)9783038351948

In order to provide better service for the users, this paper put forwards a new algorithm for network selection. Firstly, the algorithm acquires weights' vectors by analytic hierarchy process (AHP), G-1, entropy weighting method (EW) and variable coefficient (VC). Then combine the weights' vector according to the similarity of different methods. Finally select the target network with the best performance. The simulation results show that the proposed algorithm can provide subscribers with better quality of service. © (2014) Trans Tech Publications, Switzerland.

关键词： Heterogeneous networks

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Joint spectrum and power allocation for femtocell based on graph and game theory

Joint spectrum and power allocation for femtocell based on g...

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4th International Conference on Materials Science and Information technology, MSIT 2014

作者： Wang, Ying Zhu, Qi Jiangsu Key Lab of Wireless Communications Key Lab on Wideband Wireless Communications and Sensor Network Technology of Ministry of Education Nanjing University of Posts and Telecommunications Jiangsu Nanjing 210003 China

ISBN: (纸本)9783038351733

In order to mitigate the downlink interference in two-tier femtocell networks, a joint spectrum and power allocation algorithm based on graph and game theory is proposed in this paper. On the premise of ensuring the QoS (Quality of Service) of MUEs (microcell user equipments), we first adopt graph-based clustering algorithm to assign subbands to femtocells. Then, for femtocells of each cluster, their transmitting power is redistributed based on the non-cooperative game theory to further reduce the interference among them. Simulation results show that this algorithm can further improves the performance of the entire system compared with pure clustering strategy and ensures the QoS of MUEs at the same time. © (2014) Trans Tech Publications, Switzerland.

关键词： Game theory

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sensor node-assisted asynchronous cooperative spectrum sensing for cognitive radio network

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The Journal of China Universities of Posts and Telecommunications 2014年第5期21卷 17-23页

作者： CAO Kai-tian WANG Dong-lin Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications National Mobile Communications Research Laboratory Southeast University Department of Electrical and Computer Engineering New York Institute of Technology (Nanjing Campus)

In order to take advantage of the asynchronous sensing information, alleviate the sensing overhead of secondary users （SUs） and improve the detection performance, a sensor node-assisted asynchronous cooperative spectrum sensing （SN-ACSS） scheme for cognitive radio （CR） network （CRN） was proposed. In SN-ACSS, each SU is surrounded by sensor nodes （SNs）, which asynchronously make hard decisions and soft decisions based on the Bayesian fusion rule instead of the SU. The SU combines these soft decisions and makes the local soft decision. Finally, the fusion center （FC） fuses the local soft decisions transmitted from SUs with different weight coefficients to attain the final soft decision. Besides, the impact of the statistics of licensed band occupancy on detection performance and the fact that different SNs have different sensing contributions are also considered in SN-ACSS scheme. Numerical results show that compared with the conventional synchronous cooperative spectrum sensing （SCSS） and the existing ACSS schemes, SN-ACSS algorithm achieves a better detection performance and lower cost with the same number of SNs.

关键词： cognitive radio asynchronous cooperative spectrum sensing Bayesian fusion rule ON-OFF model soft decision

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A delay-constrained energy-efficient component carrier adjusting scheme for LTE-Advanced systems

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High technology Letters 2014年第3期20卷 237-244页

作者：陈华夏 Hu Honglin Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology(SIMIT)Chinese Academy of Sciences(CAS) University of Chinese Academy of Sciences Shanghai Research Center for Wireless Communications(WiCO)

The energy efficiency and packet delay tradeoffs in long term evolution-advanced(LTE-A) systems are *** expressions are derived to explain the relation of energy efficiency to mean packet delay,arrival rate and component carrier(CC) configurations,from the theoretical respective which reveals that the energy efficiency of multiple CC systems is closely related to the frequency of CCs and the number of active *** on the theoretical analysis,a CC adjusting scheme for LTE-A systems is proposed to maximize energy efficiency subject to delay constraint by dynamically altering the on/off state of CCs according to traffic *** and simulation results show that for CCs in different frequency bands with equal transmit power,the proposed scheme could significantly improve the energy efficiency of users in all aggregation levels within the constraint of mean packet delay.

关键词： energy efficiency carrier aggregation （CA） delay constraint component carrier（CC） scheduling long term evolution-advanced systems

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