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MULTI-HOP RELAYING IN 5G: FROM RESEARCH TO SYSTEMS, STANDARDS, AND APPLICATIONS
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作者 lei guo keping long +1 位作者 kumudu munasinghe xuetao wei 《China Communications》 SCIE CSCD 2016年第10期I0001-I0002,共2页
In recent years,the demands of high traffic transmission motivate the rapid development of wireless access techniques,and it becomes promising to design the fifth generation(5G)wireless networks.Essential requirements... In recent years,the demands of high traffic transmission motivate the rapid development of wireless access techniques,and it becomes promising to design the fifth generation(5G)wireless networks.Essential requirements for 5G involve higher traffic volume,indoor or hotspot traffic,and spectrum,energy,and cost efficien- 展开更多
关键词 multi-hop relayING IN 5G STANDARDS AND APPLICATIONS FROM RESEARCH TO SYSTEMS
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Secure Wireless Multicasting through Nakagami-m Fading Channels with Multi-Hop Relaying
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作者 Md. Mizanur Rahman Md. Zahurul Islam Sarkar Mohammad Mahmud Hasan 《Journal of Computer and Communications》 2023年第5期177-193,共17页
The additional diversity gain provided by the relays improves the secrecy capacity of communications system significantly. The multiple hops in the relaying system is an important technique to improve this diversity g... The additional diversity gain provided by the relays improves the secrecy capacity of communications system significantly. The multiple hops in the relaying system is an important technique to improve this diversity gain. The development of an analytical mathematical model of ensuring security in multicasting through fading channels incorporating this benefit of multi-hop relaying is still an open problem. Motivated by this issue, this paper considers a secure wireless multicasting scenario employing multi-hop relaying technique over frequency selective Nakagami-m fading channel and develops an analytical mathematical model to ensure the security against multiple eavesdroppers. This mathematical model has been developed based on the closed-form analytical expressions of the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multicasting (SOPM) to ensure the security in the presence of multiple eavesdroppers. Moreover, the effects of the fading parameter of multicast channel, the number of hops and eavesdropper are investigated. The results show that the security in multicasting through Nakagami-m fading channel with multi-hop relaying system is more sensitive to the number of hops and eavesdroppers. The fading of multicast channel helps to improve the secrecy multicast capacity and is not the enemy of security in multicasting. 展开更多
关键词 Frequency Selective Fading multi-hop relaying Probability of Non-Zero Secrecy Multicast Capacity Secure Outage Probability for Multicasting
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Power-Effective in the Cell Sectorization Using Wide-Beam and Narrow-Beam for Multi-hop Relay Network 被引量:1
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作者 仇润鹤 周立峰 金彦龄 《Journal of Donghua University(English Edition)》 EI CAS 2011年第1期100-103,共4页
Multi-hop relay is a significant topic in the wireless communication and it is provisioned in the 802.16j standards.At present,the major research on multi-hop relay is focused on the capacity,coverage,coordination,thr... Multi-hop relay is a significant topic in the wireless communication and it is provisioned in the 802.16j standards.At present,the major research on multi-hop relay is focused on the capacity,coverage,coordination,throughput,etc.But in this paper,a new concept about power-effective was discussed.Then,two power-effective coverage extension methods using two sectorized cellular approaches were introduced,i.e.,the widebeam three sector cell(WBTC) and the narrow-beam three sector cell(NBTC).Under such topologies,the consumption of power and optimal numbers of base stations(BSs) and relay stations(RSs) with respect to various user traffic densities were investigated.Finally,it is found that the performance of WBTC is better than NBTC. 展开更多
关键词 multi-hop power-effective wide-beam three sector cell(WBTC) narrow-beam three sector cell(NBTC)
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Multi-hop relay-based maritime visible light communication
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作者 Hyeong-Ji Kim Samrat Vikramaditya Tiwari Yeon-Ho Chung 《Chinese Optics Letters》 SCIE EI CAS CSCD 2016年第5期29-33,共5页
This Letter presents a multi-hop relay visible light communication (VLC) system for maritime applications. Maritime VLC systems suffer from limited coverage distance due inherently to the usage of light-emitting dio... This Letter presents a multi-hop relay visible light communication (VLC) system for maritime applications. Maritime VLC systems suffer from limited coverage distance due inherently to the usage of light-emitting diodes and photodetectors. The proposed system employs a multiple of decode-and-forward relays to extend coverage distance in maritime environments. The multi-hop relay based maritime VLC is analyzed under a maritime channel modeled by the JONSWAP spectrum and gamma-gamma distribution. It is found that the use of relays in maritime environments can extend the coverage distance significantly and also improve the performance. In addition, the performance of the system is analyzed using various combining techniques at the receiver to enhance the performance. The maximal ratio combining technique is found to provide superior link quality in maritime environments. 展开更多
关键词 VLC multi-hop relay-based maritime visible light communication
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Multi-Hop Free Space Optical Communications Using Serial Decode-and-Forward Relay Transmissions 被引量:1
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作者 王俊波 焦媛 +2 位作者 陈明 王金元 曹哲 《China Communications》 SCIE CSCD 2011年第5期102-110,共9页
This paper investigates the performance of multi-hop Free Space Optical(FSO) communications using serial Decode-and-Forward(DF) relay transmissions.A statistical model for the optical intensity fluctuation at the rece... This paper investigates the performance of multi-hop Free Space Optical(FSO) communications using serial Decode-and-Forward(DF) relay transmissions.A statistical model for the optical intensity fluctuation at the receiver due to the combined effects of atmospheric turbulence-induced fading,mis alignment fading and pass-loss is presented.Under given weather and mis alignment conditions,a closed-form analytical expression for the end-to-end outage probability of serial Decode-and-Forward(DF) multi-hop FSO communications is derived.Numerical results show that the serial DF multi-hop transmission is a promising technology to enhance the performance of FSO communications.Moreover,the derived analytical expression can provide close approximations to the simulation results. 展开更多
关键词 free-space optical systems pointing errors atmospheric turbulence outage probability multi-hop transmission
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Multiway Relay Based Framework for Network Coding in Multi-Hop WSNs
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作者 Vinod Kumar Menaria Anand Nayyar +1 位作者 Sandeep Kumar Ketan Kotecha 《Computers, Materials & Continua》 SCIE EI 2023年第1期1199-1216,共18页
In today’s information technology(IT)world,the multi-hop wireless sensor networks(MHWSNs)are considered the building block for the Internet of Things(IoT)enabled communication systems for controlling everyday tasks o... In today’s information technology(IT)world,the multi-hop wireless sensor networks(MHWSNs)are considered the building block for the Internet of Things(IoT)enabled communication systems for controlling everyday tasks of organizations and industry to provide quality of service(QoS)in a stipulated time slot to end-user over the Internet.Smart city(SC)is an example of one such application which can automate a group of civil services like automatic control of traffic lights,weather prediction,surveillance,etc.,in our daily life.These IoT-based networks with multi-hop communication and multiple sink nodes provide efficient communication in terms of performance parameters such as throughput,energy efficiency,and end-to-end delay,wherein low latency is considered a challenging issue in next-generation networks(NGN).This paper introduces a single and parallels stable server queuing model with amulti-class of packets and native and coded packet flowto illustrate the simple chain topology and complexmultiway relay(MWR)node with specific neighbor topology.Further,for improving data transmission capacity inMHWSNs,an analytical framework for packet transmission using network coding at the MWR node in the network layer with opportunistic listening is performed by considering bi-directional network flow at the MWR node.Finally,the accuracy of the proposed multi-server multi-class queuing model is evaluated with and without network coding at the network layer by transmitting data packets.The results of the proposed analytical framework are validated and proved effective by comparing these analytical results to simulation results. 展开更多
关键词 multi-hop wireless sensor networks network coding multiway relay node THROUGHPUT multi-server multi-class queuing models
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Outage Probability Based on Relay Selection Method for Multi-Hop Device-to-Device Communication
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作者 HAI Han QIAN Hongzhi +1 位作者 FENG Hongzhan YU Jinming 《Journal of Donghua University(English Edition)》 CAS 2021年第3期214-220,共7页
To improve the connectivity of device-to-device(D2D)communication between delay-assisted vehicles,a multi-hop D2D relay selection strategy based on outage probability is proposed.The algorithm firstly clusters the rel... To improve the connectivity of device-to-device(D2D)communication between delay-assisted vehicles,a multi-hop D2D relay selection strategy based on outage probability is proposed.The algorithm firstly clusters the relay users based on the distance of D2D users,and determines the number of one-hop relay nodes through the outage probability threshold.Two-hop relay nodes directly select the same number of relays as one-hop relay nodes according to the descending order of signal noise ratio(SNR)to establish a square matrix.The Hungarian algorithm is used to assign the relay nodes of two clusters to complete the inter relay communication.Finally,the information is sent to the D2D receiver by combining technology.The simulation results show that this algorithm can reduce the cost of relay probing process and the outage probability of system in multi-hop D2D relay communication. 展开更多
关键词 multi-hop device-to-device(D2D) vehicle communication relay selection Hungarian algorithm
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Multi-Hop Transmission Method of 5G Millimeter Wave Relay Based on Network Coding
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作者 Yilin Wang Weisheng He +3 位作者 Xuwei Fan Lianfen Huang Jie Yang Yuliang Tang 《China Communications》 SCIE CSCD 2022年第12期14-26,共13页
With the rapid development of the Internet technology,millimeter wave(mmWave)will be used as a supplement to 5G low frequency bands to meet the extremely high system capacity requirements of 5G in hot spots.Although 5... With the rapid development of the Internet technology,millimeter wave(mmWave)will be used as a supplement to 5G low frequency bands to meet the extremely high system capacity requirements of 5G in hot spots.Although 5G mmWave communication can adapt to the needs of 5G network and carry a large amount of transmitted data,transmission stability has become one of the key technical issues of 5G network mmWave communication due to problems such as strong attenuation and poor penetration of mmWave.In order to improve the efficiency of the mmWave multi-hop transmission,we propose a 5G mmWave multi-hop transmission method based on network coding,which can adapt to the current wireless network environment,improve spectrum efficiency and increase network throughput.Based on MATLAB simulation experiments,it is verified that the proposed method can greatly improve the transmission efficiency and reduce the signal loss under the premise of ensuring the accurate signal transmission. 展开更多
关键词 5G network millimeter wave relay multihop communication network coding
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Cooperative Relay Selection Mechanism in Multi-Hop Networks
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作者 Jian Liu Lei Wang +1 位作者 Changming Zhao Alan Yang 《Computers, Materials & Continua》 SCIE EI 2020年第4期119-130,共12页
In this paper, we consider a three-hop relay system based on interference cancellation technique in Underlay cognitive radio (CR) network. Although underlay CR has been shown as a promising technique to better utilize... In this paper, we consider a three-hop relay system based on interference cancellation technique in Underlay cognitive radio (CR) network. Although underlay CR has been shown as a promising technique to better utilize the source of primary users (PUs), its secondary performance will be severely degraded. On one hand, by adapting the Underlay spectrum sharing pattern, secondary users (SUs) would observe the strict power constraints and be interfered by primary users. On the other hand, limited transmit power results in limited transmission range, which greatly degrade the secondary transmission capacity. To solve the problems above, we propose an interference cancellation protocol for multi-hop wireless communication networks in underlay CR, which could develop the long-distance transmission performance and improve the transmission efficiency significantly. As simulation results shows, proposed scheme significantly reduce the secondary outage probability and increase the secondary diversity than the traditional cases. 展开更多
关键词 Cognitive relay networks interference cancellation power control secondary outage probability
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基于Relay的低成本4G网络覆盖增强方法
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作者 韩亚洁 《长江信息通信》 2024年第8期205-208,共4页
无缝覆盖是无线移动通信网络的重要特点之一。对于人烟稀少地区,比如海面,沙漠等场景,需要进行低成本的超远无线通信覆盖。但是,如果单纯地通过架设基站满足这类超远覆盖会增加运营商的基站造价成本。文章分析比较4G网络的覆盖增强部署... 无缝覆盖是无线移动通信网络的重要特点之一。对于人烟稀少地区,比如海面,沙漠等场景,需要进行低成本的超远无线通信覆盖。但是,如果单纯地通过架设基站满足这类超远覆盖会增加运营商的基站造价成本。文章分析比较4G网络的覆盖增强部署方法,提出基于Relay的低成本覆盖增强方法。其核心思想是:根据4G网络覆盖范围要求,部署4G网络中继节点,确定网络基站和中继节点之间无线通信的最少上行子帧个数。同时,结合4G无线移动通信系统模式确定可选的中继部署类型和配置,从而实现低成本、高质量的4G网络增强覆盖。 展开更多
关键词 relay 覆盖增强 4G
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Optimization of Cooperative RelayingMolecular Communications for Nanomedical Applications
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作者 Eman S.Attia Ashraf A.M.Khalaf +4 位作者 Fathi E.Abd El-Samie Saied M.Abd El-atty Konstantinos A.Lizos Osama Alfarraj Heba M.El-Hoseny 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第2期1259-1275,共17页
Recently,nano-systems based on molecular communications via diffusion(MCvD)have been implemented in a variety of nanomedical applications,most notably in targeted drug delivery system(TDDS)scenarios.Furthermore,becaus... Recently,nano-systems based on molecular communications via diffusion(MCvD)have been implemented in a variety of nanomedical applications,most notably in targeted drug delivery system(TDDS)scenarios.Furthermore,because the MCvD is unreliable and there exists molecular noise and inter symbol interference(ISI),cooperative nano-relays can acquire the reliability for drug delivery to targeted diseased cells,especially if the separation distance between the nano transmitter and nano receiver is increased.In this work,we propose an approach for optimizing the performance of the nano system using cooperative molecular communications with a nano relay scheme,while accounting for blood flow effects in terms of drift velocity.The fractions of the molecular drug that should be allocated to the nano transmitter and nano relay positioning are computed using a collaborative optimization problem solved by theModified Central Force Optimization(MCFO)algorithm.Unlike the previous work,the probability of bit error is expressed in a closed-form expression.It is used as an objective function to determine the optimal velocity of the drug molecules and the detection threshold at the nano receiver.The simulation results show that the probability of bit error can be dramatically reduced by optimizing the drift velocity,detection threshold,location of the nano-relay in the proposed nano system,and molecular drug budget. 展开更多
关键词 Nanomedical system molecular communication cooperative relay OPTIMIZATION
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Coordinated responses of leaf and nodule traits contribute to the accumulation of N in relay intercropped soybean
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作者 Ping Chen Qing Du +8 位作者 Benchuan Zheng Huan Yang Zhidan Fu Kai Luo Ping Lin Yilin Li Tian Pu Taiwen Yong Wenyu Yang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第6期1910-1928,共19页
Maize(Zea mays L.)-soybean(Glycine max L.Merr.)relay intercropping provides a way to enhance land productivity.However,the late-planted soybean suffers from shading by the maize.After maize harvest,how the recovery gr... Maize(Zea mays L.)-soybean(Glycine max L.Merr.)relay intercropping provides a way to enhance land productivity.However,the late-planted soybean suffers from shading by the maize.After maize harvest,how the recovery growth influences the leaf and nodule traits remains unclear.A three-year field experiment was conducted to evaluate the effects of genotypes,i.e.,supernodulating(nts1007),Nandou 12(ND12),and Guixia 3(GX3),and crop configurations,i.e.,the interspecific row spacing of 45(I45),60(I60),75 cm(I75),and sole soybean(SS),on soybean recovery growth and N fixation.The results showed that intercropping reduced the soybean total leaf area(LA)by reducing both the leaf number(LN)and unit leaflet area(LUA),and it reduced the nodule dry weight(NW)by reducing both the nodule number(NN)and nodule diameter(ND)compared with the SS.The correlation and principal component analysis(PCA)indicated a co-variability of the leaf and nodule traits in response to the genotype and crop configuration interactions.During the recovery growth stages,the compensatory growth promoted soybean growth to reduce the gaps of leaf and nodule traits between intercropping and SS.The relative growth rates of ureide(RGR_U)and nitrogen(RGR_N)accumulation were higher in intercropping than in SS.Intercropping achieved more significant sucrose and starch contents compared with SS.ND12 and GX3 showed more robust compensatory growth than nts1007 in intercropping.Although the recovery growth of relay intercropping soybean improved biomass and nitrogen accumulation,ND12 gained a more significant partial land equivalent ratio(pLER)than GX3.The I60 treatment achieved more robust compensation effects on biomass and N accumulation than the other configurations.Meanwhile,I60 showed a higher nodule sucrose content and greater shoot ureide and N accumulation than SS.Finally,intercropping ND12 with maize using an interspecific row spacing of 60 cm was optimal for both yield advantage and N accumulation. 展开更多
关键词 relay intercropping GENOTYPE crop configuration symbiotic nitrogen fixation SOYBEAN NODULE
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A Pricing-Based Cooperative Relay Selection Scheme for Reliable Communications
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作者 Xiao Yulong Wu Yu +2 位作者 Amr Tolba Chen Ziqiang Li Tengfei 《China Communications》 SCIE CSCD 2024年第8期30-44,共15页
With the rapid development and application of energy harvesting technology,it has become a prominent research area due to its significant benefits in terms of green environmental protection,convenience,and high safety... With the rapid development and application of energy harvesting technology,it has become a prominent research area due to its significant benefits in terms of green environmental protection,convenience,and high safety and efficiency.However,the uneven energy collection and consumption among IoT devices at varying distances may lead to resource imbalance within energy harvesting networks,thereby resulting in low energy transmission efficiency.To enhance the energy transmission efficiency of IoT devices in energy harvesting,this paper focuses on the utilization of collaborative communication,along with pricing-based incentive mechanisms and auction strategies.We propose a dynamic relay selection scheme,including a ladder pricing mechanism based on energy level and a Kuhn-Munkre Algorithm based on an auction theory employing a negotiation mechanism,to encourage more IoT devices to participate in the collaboration process.Simulation results demonstrate that the proposed algorithm outperforms traditional algorithms in terms of improving the energy efficiency of the system. 展开更多
关键词 cooperative communication edge net-work energy harvesting relay selection
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System design and validation of Queqiao-2 lunar relay communication satellite
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作者 ZHANG Lihua XIONG Liang +11 位作者 SUN Ji CHEN Luojing XIAO Chuan ZHOU Wenyan WANG Yong LIU Wangwang GUAN Yifeng CHEN Tao YU Xiaochuan XU Jin CHEN Guohui CAO Xiaoping 《中国空间科学技术(中英文)》 CSCD 北大核心 2024年第5期23-39,共17页
In order to provide relay communication supports for future Chinese lunar exploration program,Queqiao-2 relay communication satellite was developed.Queqiao-2 can perform scientific observations with three kinds of sci... In order to provide relay communication supports for future Chinese lunar exploration program,Queqiao-2 relay communication satellite was developed.Queqiao-2 can perform scientific observations with three kinds of scientific instruments on board.The system design of Queqiao-2,including mission orbit and transfer orbit design,configuration and layout design,housekeeping and information flow design,power supply and distribution design,GNC and propulsion system design,communication links design,etc.,was accomplished through comprehensive tradeoff and evaluation on technical maturity,availability,schedule,cost,and so on.With a view to reducing development risk,both the platform and relay communication payloads were developed based on significant heritage from previous Queqiao relay satellite and other relevant spacecraft.Queqiao-2 features flexible system architecture to support multiple frequencies,modulations,data rates and software reconfigurations to meet new user requirements.Subsequent to a successful launch on March 20,2024,by means of 5 orbit maneuvers,Queqiao-2 was inserted into a highly elliptical frozen mission orbit around the moon with a 24h period on schedule.Following on-orbit tests and calibrations,Queqiao-2 has possessed the capacity to provide reliable relay communication services to multiple lunar exploration missions,as well as the capacity to perform scientific observations.Under the support of Queqiao-2,Chang′e-6 achieved its ambitious mission goal to collect and return samples from the moon′s mysterious far side.In the meanwhile,Queqiao-2 has also paved the way for the following Chinese lunar exploration missions including Chang′e-7 and Chang′e-8.The design life time of Queqiao-2 is more than 8 years.Benefit from flexibility and extensibility of relay communication system design,it is convenient to provide relay communication services for future lunar exploration missions of both China and other countries.In addition,innovative scientific observations would be performed during the period that no relay communication task is arranged.The system design of Queqiao-2 reflects the development philosophy of technical innovations and inheritance integration.Based on highly flexible and extensible system architecture,multiple and concurrent relay communication mission requirements can be met.It can provide strong supports for future lunar exploration missions.Successful launching,orbit entering and on-orbit tests of Queqiao-2 verified the correct design principle and versatility.By means of Queqiao-2,more innovative scientific outcomes are anticipated and lunar exploration activities can be facilitated. 展开更多
关键词 lunar explorations relay communication Queqiao system design TEST VALIDATION
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Security-Reliability Tradeoff Analysis for Jamming Aided Decode-and-Forward Relay Networks
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作者 Zou Ronggui Zou Yulong +1 位作者 Zhu Jia Li Bin 《China Communications》 SCIE CSCD 2024年第5期218-228,共11页
In this paper,we explore a cooperative decode-and-forward(DF)relay network comprised of a source,a relay,and a destination in the presence of an eavesdropper.To improve physical-layer security of the relay system,we p... In this paper,we explore a cooperative decode-and-forward(DF)relay network comprised of a source,a relay,and a destination in the presence of an eavesdropper.To improve physical-layer security of the relay system,we propose a jamming aided decodeand-forward relay(JDFR)scheme combining the use of artificial noise and DF relaying which requires two stages to transmit a packet.Specifically,in stage one,the source sends confidential message to the relay while the destination acts as a friendly jammer and transmits artificial noise to confound the eavesdropper.In stage two,the relay forwards its re-encoded message to the destination while the source emits artificial noise to confuse the eavesdropper.In addition,we analyze the security-reliability tradeoff(SRT)performance of the proposed JDFR scheme,where security and reliability are evaluated by deriving intercept probability(IP)and outage probability(OP),respectively.For the purpose of comparison,SRT of the traditional decode-and-forward relay(TDFR)scheme is also analyzed.Numerical results show that the SRT performance of the proposed JDFR scheme is better than that of the TDFR scheme.Also,it is shown that for the JDFR scheme,a better SRT performance can be obtained by the optimal power allocation(OPA)between the friendly jammer and user. 展开更多
关键词 decode-and-forward relay friendly jammer physical layer security power allocation security-reliability tradeoff
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Improving throughput in SWIPT-based wireless multirelay networks with relay selection and rateless codes
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作者 Gaofei Huang Qihong Zhong +2 位作者 Hui Zheng Sai Zhao Dong Tang 《Digital Communications and Networks》 SCIE CSCD 2024年第4期1131-1144,共14页
This paper studies a dual-hop Simultaneous Wireless Information and Power Transfer(SWIPT)-based multi-relay network with a direct link.To achieve high throughput in the network,a novel protocol is first developed,in w... This paper studies a dual-hop Simultaneous Wireless Information and Power Transfer(SWIPT)-based multi-relay network with a direct link.To achieve high throughput in the network,a novel protocol is first developed,in which the network can switch between a direct transmission mode and a Single-Relay-Selection-based Cooperative Transmission(SRS-CT)mode that employs dynamic decode-and-forward relaying accomplished with Rateless Codes(RCs).Then,under this protocol,an optimization problem is formulated to jointly optimize the network operation mode and the resource allocation in the SRS-CT mode.The formulated problem is difficult to solve because not only does the noncausal Channel State Information(CSI)cause the problem to be stochastic,but also the energy state evolution at each relay is complicated by network operation mode decision and resource allocation.Assuming that noncausal CSI is available,the stochastic optimization issue is first to be addressed by solving an involved deterministic optimization problem via dynamic programming,where the complicated energy state evolution issue is addressed by a layered optimization method.Then,based on a finite-state Markov channel model and assuming that CSI statistical properties are known,the stochastic optimization problem is solved by extending the result derived for the noncausal CSI case to the causal CSI case.Finally,a myopic strategy is proposed to achieve a tradeoff between complexity and performance without the knowledge of CSI statistical properties.The simulation results verify that our proposed SRS-and-RC-based design can achieve a maximum of approximately 40%throughput gain over a simple SRS-and-RC-based baseline scheme in SWIPT-based multi-relay networks. 展开更多
关键词 Simultaneous wireless information and power TRANSFER Energy harvesting relay networks Throughput maximization
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Beamforming Design for IRS-and-UAV-Aided Two-Way Amplify-and-Forward Relay Networks in Maritime IoT
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作者 Wang Xuehui Shu Feng +6 位作者 Wu Yuanyuan Shi Weiping Yan Shihao Zhao Yifan Cheng Qiankun Sun Zhongwen Wang Jiangzhou 《China Communications》 SCIE CSCD 2024年第8期45-61,共17页
In this paper,an intelligent reflecting surface(IRS)-and-unmanned aerial vehicle(UAV)-assisted two-way amplify-and-forward(AF)relay network in maritime Internet of Things(IoT)is proposed,where ship1(S1)and ship2(S2)ca... In this paper,an intelligent reflecting surface(IRS)-and-unmanned aerial vehicle(UAV)-assisted two-way amplify-and-forward(AF)relay network in maritime Internet of Things(IoT)is proposed,where ship1(S1)and ship2(S2)can be viewed as data collecting centers.To enhance the message exchange rate between S1 and S2,a problem of maximizing minimum rate is cast,where the variables,namely AF relay beamforming matrix and IRS phase shifts of two time slots,need to be optimized.To achieve a maximum rate,a low-complexity alternately iterative(AI)scheme based on zero forcing and successive convex approximation(LC-ZF-SCA)algorithm is presented.To obtain a significant rate enhancement,a high-performance AI method based on one step,semidefinite programming and penalty SCA(ONSSDP-PSCA)is proposed.Simulation results show that by the proposed LC-ZF-SCA and ONS-SDP-PSCA methods,the rate of the IRS-and-UAV-assisted AF relay network surpass those of with random phase and only AF relay networks.Moreover,ONS-SDP-PSCA perform better than LC-ZF-SCA in aspect of rate. 展开更多
关键词 BEAMFORMING maritime Internet of Things phase shift rate performance two-way amplify-and-forward relay unmanned aerial vehicle
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Designing a Protection Scheme in Micro-Grid Systems with DG Using Central Protection Unite and Multiple Setting Group Protection Relays
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作者 Mostafa I. Saleh Gaber El-Saady +1 位作者 Ali M. Yousef El-Noby A. Ibrahim 《Journal of Power and Energy Engineering》 2024年第9期37-49,共13页
Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this... Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains. 展开更多
关键词 Directional Overcurrent relay Protection Coordination Distributed Generators Central Protection Unite Multiple Setting Group Protection relay
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Security-Reliability Analysis and Optimization for Cognitive Two-Way Relay Network with Energy Harvesting
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作者 Luo Yi Zhou Lihua +3 位作者 Dong Jian Sun Yang Xu Jiahui Xi Kaixin 《China Communications》 SCIE CSCD 2024年第11期163-179,共17页
This paper investigates the security and reliability of information transmission within an underlay wiretap energy harvesting cognitive two-way relay network.In the network,energy-constrained secondary network(SN)node... This paper investigates the security and reliability of information transmission within an underlay wiretap energy harvesting cognitive two-way relay network.In the network,energy-constrained secondary network(SN)nodes harvest energy from radio frequency signals of a multi-antenna power beacon.Two SN sources exchange their messages via a SN decode-and-forward relay in the presence of a multiantenna eavesdropper by using a four-phase time division broadcast protocol,and the hardware impairments of SN nodes and eavesdropper are modeled.To alleviate eavesdropping attacks,the artificial noise is applied by SN nodes.The physical layer security performance of SN is analyzed and evaluated by the exact closed-form expressions of outage probability(OP),intercept probability(IP),and OP+IP over quasistatic Rayleigh fading channel.Additionally,due to the complexity of OP+IP expression,a self-adaptive chaotic quantum particle swarm optimization-based resource allocation algorithm is proposed to jointly optimize energy harvesting ratio and power allocation factor,which can achieve security-reliability tradeoff for SN.Extensive simulations demonstrate the correctness of theoretical analysis and the effectiveness of the proposed optimization algorithm. 展开更多
关键词 artificial noise energy harvesting cognitive two-way relay network hardware impairments physical layer security security-reliability tradeoff self-adaptive quantum particle swarm optimization
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Average Secrecy Capacity of the Reconfigurable Intelligent Surface-Assisted Integrated Satellite Unmanned Aerial Vehicle Relay Networks
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作者 Ping Li Kefeng Guo +2 位作者 Feng Zhou XuelingWang Yuzhen Huang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第2期1849-1864,共16页
Integrated satellite unmanned aerial vehicle relay networks(ISUAVRNs)have become a prominent topic in recent years.This paper investigates the average secrecy capacity(ASC)for reconfigurable intelligent surface(RIS)-e... Integrated satellite unmanned aerial vehicle relay networks(ISUAVRNs)have become a prominent topic in recent years.This paper investigates the average secrecy capacity(ASC)for reconfigurable intelligent surface(RIS)-enabled ISUAVRNs.Especially,an eve is considered to intercept the legitimate information from the considered secrecy system.Besides,we get detailed expressions for the ASC of the regarded secrecy system with the aid of the reconfigurable intelligent.Furthermore,to gain insightful results of the major parameters on the ASC in high signalto-noise ratio regime,the approximate investigations are further gotten,which give an efficient method to value the secrecy analysis.At last,some representative computer results are obtained to prove the theoretical findings. 展开更多
关键词 Integrated satellite unmanned aerial vehicle relay networks reconfigurable intelligent surface average secrecy capacity(ASC) asymptotic ASC
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