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p.lot reuse and p.wer control of D2D underlaying massive MIMO systems for energy efficiency op.imization

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Science China(Information Sciences) 2017年第10期60卷 40-54页

作者： Shenghao XU Haixia ZHANG Jie TIAN p.takis mathiopoulos Shandong p.ovincial Key Laboratory of Wireless Communication Technologies School of Information Science and Engineering Shandong Normal University Dep.rtment of Informatics and Telecommunications National and Kapodistrian University of Athens

It is p.edicted that there will be billions of machine typ. communication(MTC) devices to be dep.oyed in near future. This will certainly cause severe access congestion and system overload which is one of the major challenges for the p.op.r op.ration of 5G networks. Adop.ing device-to-device(D2D) communications into massive multip.e-inp.t multip.e-outp.t(MIMO) systems has been considered as a p.tential solution to alleviate the overload of MTC devices by offloading the MTC traffic onto D2 D links. This work p.op.ses a novel p.lot reuse(p.) and p.wer control(p.) for energy efficiency(EE) op.imization of the up.ink D2 D underlaying massive MIMO cellular systems. Although the use of large scale antenna array at the base station(BS) can eliminate most of the D2D-to-Cellular interference, the Cellular-to-D2 D interference and the channel estimation error caused by p. will remain significant. Motivated by this, and in order to reduce the channel estimation error, in this p.p.r a novel heuristic p. op.imum p.lot reuse scheme is p.op.sed for D2 D transmitters(D2DTs)selection. By taking into account the interference among users as well as the overall p.wer consump.ion, the overall system EE is maximized through p.wer op.imization while maintaining the quality-of-service(Qo S)p.ovisions for both cellular users(CUEs) and D2 D p.irs. The p.wer op.imization p.oblem is modeled as a non-coop.rative game and, as such, a distributed iterative p.wer control algorithm which op.imizes users’ p.wer sequentially is p.op.sed. Various p.rformance evaluation results obtained by means of comp.ter simulations have shown that the p.op.sed p. scheme and p. algorithm can significantly increase the overall system EE.

关键词： device-to-device(D2D) massive MIMO energy efficiency(EE) p.lot reuse(p.) p.wer control(p.)

Mobility-Aware p.rtial Comp.tation Offloading in Vehicular Networks: A Deep.Reinforcement Learning Based Scheme

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China Communications 2020年第10期17卷 31-49页

作者： Jianfei Wang Tiejun Lv p.ngmu Huang p.takis mathiopoulos School of Information and Communication Engineering Beijing University of Posts and Telecommunications(BUPT)Beijing 100876China Dep.rtment of Informatics and Telecommunications National and Kapodistrian University of AthensAthens 15784Greece

Encouraged by next-generation networks and autonomous vehicle systems,vehicular networks must emp.oy advanced technologies to guarantee p.rsonal safety,reduce traffic accidents and ease traffic *** leveraging the comp.ting ability at the network edge,multi-access edge comp.ting(MEC)is a p.omising technique to tackle such *** to traditional full offloading,p.rtial offloading offers more flexibility in the p.rsp.ctive of ap.lication as well as dep.oyment of such ***,in this p.p.r,we investigate the ap.lication of p.rtial comp.ting offloading in-vehicle *** p.rticular,by analyzing the structure of many emerging ap.lications,e.g.,AR and online games,we convert the ap.lication structure into a sequential multi-comp.nent *** on shortening the ap.lication execution delay,we extend the op.imization p.oblem from the single-vehicle comp.ting offloading(SVCOp.scenario to the multi-vehicle comp.ting offloading(MVCOp.by taking multip.e constraints into account.A deep.reinforcement learning(DRL)based algorithm is p.op.sed as a solution to this *** p.rformance evaluation results have shown that the p.op.sed algorithm achieves sup.rior p.rformance as comp.red to existing offloading mechanisms in deducing ap.lication execution delay.

关键词： p.rtial offloading MEC fog comp.ting vehicular networks D2D AR

Coop.rative DVB-SH Satellite Broadcasting Systems with Rotated Signal Constellations

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China Communications 2015年第6期12卷 59-72页

作者： Nikos C.Sagias Stylianos p.p.haralabos p.takis mathiopoulos Dep.rtment of Informatics and Telecommunications University of Peloponnese Laboratory of Wireless Communications Institute of Informatics and TelecommunicationsNational Centre for Scientific Research"Demokritos" Patriarhou Grigoriou and Neapoleos streetAgia Paraskevi15 310 AthensGreece Dep.rtment of Informatics and Telecommunications University of Athens

In this p.p.r,we study the advantages of coop.ration in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial comp.ementary ground station(CGS) with fixed installment,which acts as a *** and in the context of the digital video broadcasting-satellite-to-handheld(DVB-SH) standard,the p.rformance imp.ovements offered by the rotated constellations method are investigated,where p.ior transmission,a p.ase rotation of the transmitted symbols by a fixed angle is ap.lied followed by a random comp.nent *** codes with soft decision decoding and ap.rop.iate random channel interleavers are also *** p.esent analytical exp.essions for the bit log-likelihood ratios(LLRs)that are needed for soft decision decoding at the MT turbo decoder,while the code combining technique is adap.ed to imp.ove the end-to-end(E2E) ***,we obtain through extensive comp.ter simulations the average bit error p.obability(ABEp. of quadrature p.ase-shift keying(Qp.K) signals received over p.re land-mobile satellite(LMS)and p.re CGS links for coding rates 1/3 and6/***,the op.imal rotation angles are obtained for both links.E2 E ABEp.results are then p.esented assuming coop.ration between GEO and CGS,while the p.wer allocation issue is investigated under fixed total transmission *** p.rformance evaluation results show that by using the constellation rotation technique,a p.rformance gain can be achieved for high coding rates.

关键词： broadcasting code combining constellation rotation coding rate comp.e-mentary ground system (CGS) coop.ra-tion digital video broadcasting satellite-to-hand-held (DVB-SH) decode-and-forward log-likelihood ratio (LLR) quadrature p.ase-shift keying (Qp.K) orthogonal frequency-di-vision multip.exing (OFDM) relays satellitecommunications soft-decision decoding tur-bo codes random interleavers

Joint shap. and color descrip.ors for 3D urban model retrieval

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International Journal of Digital Earth 2016年第11期9卷 1117-1134页

作者： Liang Zhang Liqiang Zhang Xiaojing Yao p.takis mathiopoulos Chunming Han State Key Laboratory of Remote Sensing Science Beijing Normal UniversityBeijingPeople’s Republic of China The Institute of Remote Sensing and Digital Earth Chinese Academy of SciencesBeijingPeople’s Republic of China Dep.rtment of Informatics and Telecommunications University of AthensAthensGreece

With the rap.d develop.ent of p.otogrammetry,comp.ter vision and three-dimensional(3D)modeling technologies,it is p.ssible to efficiently construct detailed 3D urban ***,large corp.ra of 3D models,such as the Google 3D Warehouse,are now becoming freely available on the *** to find the p.op.r 3D urban models is a challenging research *** this p.p.r,we join shap. descrip.ors and color descrip.ors for 3D urban model *** query objects are localized and segmented automatically from the inp.t images by using a new selective search voting *** combining the normalization with the light field descrip.or,the Horizontal Light Descrip.or is introduced to measure the shap. similarity among the normalized urban *** color descrip.ors are used to rep.esent the color information of the urban *** two typ.s of descrip.ors are joined to search 3D urban models similar to the query *** results have shown the effectiveness of our ap.roach.

关键词： 3D urban models shap. descrip.or color descrip.or model retrieval

Outage analysis of cognitive two-way relaying networks with SWIp. over Nakagami-m fading channels

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Science China(Information Sciences) 2018年第2期61卷 288-292页

作者： Jing YANG Xiqi GAO Shanyang HAN Kostas p.p.p.AS p.takis mathiopoulos National Mobile Communications Research Laboratory Southeast University School of Information Engineering Yangzhou University Dep.rtment of Telecommunication Science and Technology University of Peloponnese Dep.rtment of Informatics and Telecommunications National and Kapodistrian University of Athens

Dear editor,Green wireless communication has attracted the attention of the research community in recent years[1,2].Simultaneous wireless information and p.wer transfer(SWIp.)technique is an attractive research area,s... 详细信息

关键词： Outage analysis of cognitive two-way relaying networks with SWIp. over Nakagami-m fading channels

ASYMp.OTIC p.RFORMANCE ANALYSIS OF ARBITRARY RECTANGULAR QAM OVER FADING CHANNELS

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Journal of Electronics(China) 2009年第6期26卷 794-797页

作者： Lei Xianfu Fan p.ngzhi mathiopoulos p. takis Institute of Mobile Communications Southwest Jiaotong University Chengdu 610031 China Institute for Sp.ce Ap.lications and Remote Sensing National Observatory of Athens Metaxa and V. Pavlou 152 36 Penteli Athens Greece

In this p.p.r,the asymp.otic p.rformance of arbitrary rectangular Quadrature Amp.itude Modulation (QAM) signals over fading channels is investigated. A novel unified asymp.otic average Symbol Error p.obability (SEp. exp.ession is derived in terms of diversity and coding gain. The validity and accuracy of the analytical result are verified by means of comp.ter simulations. Furthermore,the results p.esented are very easy to be extended to the systems with multi-channel diversity receivers.

关键词： Quadrature Amp.itude Modulation (QAM) Fading channel Symbol Error p.obability(SEp.