Wireless information and power transfer(WIPT) enables simultaneously communications and sustainable power supplement without the erection of power supply lines and the replacement operation of the batteries for the te...Wireless information and power transfer(WIPT) enables simultaneously communications and sustainable power supplement without the erection of power supply lines and the replacement operation of the batteries for the terminals. The application of WIPT to the underwater acoustic sensor networks(UWASNs) not only retains the long range communication capabilities, but also provides an auxiliary and convenient energy supplement way for the terminal sensors, and thus is a promising scheme to solve the energy-limited problem for the UWASNs. In this paper, we propose the integration of WIPT into the UWASNs and provide an overview on various enabling techniques for the WIPT based UWASNs(WIPT-UWASNs) as well as pointing out future research challenges and opportunities for WIPT-UWASNs.展开更多
This paper studies a simultaneous wireless information and power transfer system with multiple external eavesdroppers and internal curious users.We model the random network by Poisson cluster process in consideration ...This paper studies a simultaneous wireless information and power transfer system with multiple external eavesdroppers and internal curious users.We model the random network by Poisson cluster process in consideration of the case where eavesdroppers hide around certain targets.Focusing on the users that work in harvesting-transmitting mode with time switching receivers,we establish communication model via time division multiple access.On this basis,we propose a lightweight secure transmission scheme based on dual-thresholds for physical-layer security enhancement,which consists of two protocols applied to the downlink(DL) and uplink(UL) transmission respectively.In the DL,we design a dynamic information-power switching transmission protocol based on signal-to-noise ratio threshold,which provides an opportunistic approach to reform the fixed period allocation of information and power transfer;in the UL,an energy threshold is proposed for users to control the transmission,which is called a user-led on-off transmission protocol.Furthermore,we give a comprehensive performance analysis for the proposed scheme in terms of delay,reliability,security and secrecy throughput.Based on the analysis results,we optimize the two thresholds and the DL-UL allocationcoefficient to maximize the secrecy throughput.Simulation results show the proposed scheme can bring about a substantial secrecy gain.展开更多
Applications using simultaneous wireless information and power transfer(SWIPT)have increased significantly.Wireless communication technologies can be combined with the Internet of Things to develop many innovative app...Applications using simultaneous wireless information and power transfer(SWIPT)have increased significantly.Wireless communication technologies can be combined with the Internet of Things to develop many innovative applications using SWIPT,which is mainly based on wireless energy harvesting from electromagnetic waves used in communications.Wireless power transfer that uses magnetrons has been developed for communication technologies.Injection-locked magnetrons that can be used to facilitate high-power SWIPT for several devices are reviewed in this paper.This new technology is expected to pave the way for promoting the application of SWIPT in a wide range of fields.展开更多
Implementing self-sustainable wireless communication systems is urgent and challenging for 5G and 6G technologies.In this paper,we elaborate on a system solution using the programmable metasurface(PMS)for simultaneous...Implementing self-sustainable wireless communication systems is urgent and challenging for 5G and 6G technologies.In this paper,we elaborate on a system solution using the programmable metasurface(PMS)for simultaneous wireless information and power transfers(SWIPT),offering an optimized wireless energy management network.Both transmitting and receiving sides of the proposed solution are presented in detail.On the transmitting side,employing the wireless power transfer(WPT)technique,we present versatile power conveying strategies for near-field or far-field targets,single or multiple targets,and equal or unequal power targets.On the receiving side,utilizing the wireless energy harvesting(WEH)technique,we report our work on multi-functional rectifying metasurfaces that collect the wirelessly transmitted energy and the ambient energy.More importantly,a numerical model based on the plane-wave angular spectrum method is investigated to accurately calculate the radiation fields of PMS in the Fresnel and Fraunhofer regions.With this model,the efficiencies of WPT between the transmitter and the receiver are analyzed.Finally,future research directions are discussed,and integrated PMS for wireless information and wireless power is outlined.展开更多
无小区大规模多输入多输出(Multiple-Input Multiple-Output,MIMO)与非正交多址接入(Non-Orthogonal Multiple Access,NOMA)都是未来6G的使能技术。无线携能通信(Simultaneous Wireless Information and Power Transfer,SWIPT)技术在进...无小区大规模多输入多输出(Multiple-Input Multiple-Output,MIMO)与非正交多址接入(Non-Orthogonal Multiple Access,NOMA)都是未来6G的使能技术。无线携能通信(Simultaneous Wireless Information and Power Transfer,SWIPT)技术在进行信息解码的同时收集能量,与无小区大规模MIMO-NOMA优势互补。文中基于SWIPT研究无小区大规模MIMO-NOMA系统中的能量效率问题,通过联合优化功率分配系数和SWIPT的时隙切换(Time Switching,TS)系数,提高系统的能量效率。为了最大化能量效率,采用布谷鸟算法设计功率分配系数。考虑一种特殊情况,将所有终端的TS系数设置相同,进而推导了最佳TS系数的封闭表达式。仿真结果表明,相较于几种已有方案,文中提出的优化方案可以显著提升系统的能量效率。展开更多
Integrated data and energy transfer(IDET)is capable of simultaneously delivering on-demand data and energy to low-power Internet of Everything(Io E)devices.We propose a multi-carrier IDET transceiver relying on superp...Integrated data and energy transfer(IDET)is capable of simultaneously delivering on-demand data and energy to low-power Internet of Everything(Io E)devices.We propose a multi-carrier IDET transceiver relying on superposition waveforms consisting of multi-sinusoidal signals for wireless energy transfer(WET)and orthogonal-frequency-divisionmultiplexing(OFDM)signals for wireless data transfer(WDT).The outdated channel state information(CSI)in aging channels is employed by the transmitter to shape IDET waveforms.With the constraints of transmission power and WDT requirement,the amplitudes and phases of the IDET waveform at the transmitter and the power splitter at the receiver are jointly optimised for maximising the average directcurrent(DC)among a limited number of transmission frames with the existence of carrier-frequencyoffset(CFO).For the amplitude optimisation,the original non-convex problem can be transformed into a reversed geometric programming problem,then it can be effectively solved with existing tools.As for the phase optimisation,the artificial bee colony(ABC)algorithm is invoked in order to deal with the nonconvexity.Iteration between the amplitude optimisation and phase optimisation yields our joint design.Numerical results demonstrate the advantage of our joint design for the IDET waveform shaping with the existence of the CFO and the outdated CSI.展开更多
Micro-UAV swarms usually generate massive data when performing tasks. These data can be harnessed with various machine learning(ML) algorithms to improve the swarm’s intelligence. To achieve this goal while protectin...Micro-UAV swarms usually generate massive data when performing tasks. These data can be harnessed with various machine learning(ML) algorithms to improve the swarm’s intelligence. To achieve this goal while protecting swarm data privacy, federated learning(FL) has been proposed as a promising enabling technology. During the model training process of FL, the UAV may face an energy scarcity issue due to the limited battery capacity. Fortunately, this issue is potential to be tackled via simultaneous wireless information and power transfer(SWIPT). However, the integration of SWIPT and FL brings new challenges to the system design that have yet to be addressed, which motivates our work. Specifically,in this paper, we consider a micro-UAV swarm network consisting of one base station(BS) and multiple UAVs, where the BS uses FL to train an ML model over the data collected by the swarm. During training, the BS broadcasts the model and energy simultaneously to the UAVs via SWIPT, and each UAV relies on its harvested and battery-stored energy to train the received model and then upload it to the BS for model aggregation. To improve the learning performance, we formulate a problem of maximizing the percentage of scheduled UAVs by jointly optimizing UAV scheduling and wireless resource allocation. The problem is a challenging mixed integer nonlinear programming problem and is NP-hard in general. By exploiting its special structure property, we develop two algorithms to achieve the optimal and suboptimal solutions, respectively. Numerical results show that the suboptimal algorithm achieves a near-optimal performance under various network setups, and significantly outperforms the existing representative baselines. considered.展开更多
This paper investigates the system outage performance of a simultaneous wireless information and power transfer(SWIPT)based two-way decodeand-forward(DF)relay network,where potential hardware impairments(HIs)in all tr...This paper investigates the system outage performance of a simultaneous wireless information and power transfer(SWIPT)based two-way decodeand-forward(DF)relay network,where potential hardware impairments(HIs)in all transceivers are considered.After harvesting energy and decoding messages simultaneously via a power splitting scheme,the energy-limited relay node forwards the decoded information to both terminals.Each terminal combines the signals from the direct and relaying links via selection combining.We derive the system outage probability under independent but non-identically distributed Nakagami-m fading channels.It reveals an overall system ceiling(OSC)effect,i.e.,the system falls in outage if the target rate exceeds an OSC threshold that is determined by the levels of HIs.Furthermore,we derive the diversity gain of the considered network.The result reveals that when the transmission rate is below the OSC threshold,the achieved diversity gain equals the sum of the shape parameter of the direct link and the smaller shape parameter of the terminalto-relay links;otherwise,the diversity gain is zero.This is different from the amplify-and-forward(AF)strategy,under which the relaying links have no contribution to the diversity gain.Simulation results validate the analytical results and reveal that compared with the AF strategy,the SWIPT based two-way relaying links under the DF strategy are more robust to HIs and achieve a lower system outage probability.展开更多
针对有源可重构智能表面(reconfigurable intelligent surface,RIS)辅助的同步无线信息与能量传输(simultaneous wireless information and power transfer,SWIPT)系统,提出了一种考虑公平性的能量资源采集分配算法,以解决因乘性衰落导...针对有源可重构智能表面(reconfigurable intelligent surface,RIS)辅助的同步无线信息与能量传输(simultaneous wireless information and power transfer,SWIPT)系统,提出了一种考虑公平性的能量资源采集分配算法,以解决因乘性衰落导致的公平性能量采集性能较差的问题。在有源RIS辅助的SWIPT系统采用功率切割架构实现信息与能量的同步传输,构建了以所有用户中最小的采集能量最大化为目标函数,用户信干噪比、有源RIS和基站发射功率、功率划分因子等满足需求为约束条件的联合资源分配问题。利用交替优化、半正定松弛、连续凸近似、罚函数等技术将不能直接解决的非凸问题转换成标准凸问题,提出了一种交替迭代的公平性采集能量算法。数值仿真结果表明,所提优化算法能够显著提高用户中能量资源分配最少的用户处采集到的能量值,保障通信网络中能量资源分配的公平性。展开更多
From a circuit implementation perspective,this paper presents a brief overview of simultaneous wireless information and power transmission(SWIPT).By using zero-power batteryless wireless sensors,SWIPT mixes wireless p...From a circuit implementation perspective,this paper presents a brief overview of simultaneous wireless information and power transmission(SWIPT).By using zero-power batteryless wireless sensors,SWIPT mixes wireless power transmission with wireless communications to allow the truly practical implementation of the Internet of Things as well as many other applications.In this paper,technical backgrounds,problem formation,state-of-the-art solutions,circuit implementation examples,and system integrations of SWIPT are presented.展开更多
Wireless Power Transfer(WPT)technology can provide real-time power for many terminal devices in Internet of Things(IoT)through millimeterWave(mmWave)to support applications with large capacity and low latency.Although...Wireless Power Transfer(WPT)technology can provide real-time power for many terminal devices in Internet of Things(IoT)through millimeterWave(mmWave)to support applications with large capacity and low latency.Although the intelligent reflecting surface(IRS)can be adopted to create effective virtual links to address the mmWave blockage problem,the conventional solutions only adopt IRS in the downlink from the Base Station(BS)to the users to enhance the received signal strength.In practice,the reflection of IRS is also applicable to the uplink to improve the spectral efficiency.It is a challenging to jointly optimize IRS beamforming and system resource allocation for wireless energy acquisition and information transmission.In this paper,we first design a Low-Energy Adaptive Clustering Hierarchy(LEACH)clustering protocol for clustering and data collection.Then,the problem of maximizing the minimum system spectral efficiency is constructed by jointly optimizing the transmit power of sensor devices,the uplink and downlink transmission times,the active beamforming at the BS,and the IRS dynamic beamforming.To solve this non-convex optimization problem,we propose an alternating optimization(AO)-based joint solution algorithm.Simulation results show that the use of IRS dynamic beamforming can significantly improve the spectral efficiency of the system,and ensure the reliability of equipment communication and the sustainability of energy supply under NLOS link.展开更多
针对能量受限多中继网络的物理层安全中断性能问题,提出了基于无线携能通信(Simultaneous Wireless Information and Power Transfer,SWIPT)的多中继网络物理层安全传输方案。该方案在中继节点处采用中继选择策略以及混合功率和时间分...针对能量受限多中继网络的物理层安全中断性能问题,提出了基于无线携能通信(Simultaneous Wireless Information and Power Transfer,SWIPT)的多中继网络物理层安全传输方案。该方案在中继节点处采用中继选择策略以及混合功率和时间分割协议来实现网络安全速率最大化。对于提出的网络安全中断性能问题,首先计算出任意链路的安全中断概率闭合表达式,然后利用瑞利衰落信道的独立性和高斯切比雪夫等式,推导出了网络安全中断概率闭合表达式。为了进一步分析理论结果,推导出了在高发射功率下的网络安全中断概率闭合表达式。仿真结果验证了理论分析的正确性。仿真结果表明,增加网络中继节点数量可以显著地降低网络安全中断概率。与功率分割协议和时间切换协议相比,低发射功率下采用混合功率分割和时间转换协议能有效地提高网络安全中断性能。展开更多
以智能反射面(intelligent reflecting surface,IRS)辅助的无线携能通信(simultaneous wireless information and power transfer,SWIPT)系统为背景,研究了该系统中基于能效优先的多天线发送端有源波束成形与IRS无源波束成形联合设计与...以智能反射面(intelligent reflecting surface,IRS)辅助的无线携能通信(simultaneous wireless information and power transfer,SWIPT)系统为背景,研究了该系统中基于能效优先的多天线发送端有源波束成形与IRS无源波束成形联合设计与优化方法。以最大化接收端的最小能效为优化目标,构造在发送端功率、接收端能量阈值、IRS相移等多约束下的非线性优化问题,用交替方向乘子法(alternating direction method of multipliers,ADMM)求解。采用Dinkelbach算法转化目标函数,通过奇异值分解(singular value decomposition,SVD)和半定松弛(semi-definite relaxation,SDR)得到发送端有源波束成形向量。采用SDR得到IRS相移矩阵与反射波束成形向量。结果表明,该系统显著降低了系统能量收集(energy harvesting,EH)接收端的能量阈值。当系统总电路功耗为−15 dBm时,所提方案的用户能效为300 KB/J。当IRS反射阵源数与发送天线数均为最大值时,系统可达最大能效。展开更多
针对协作非正交多址接入(Non-orthogonal Multiple Access,NOMA)系统中用户充当中继并存在窃听者的场景,提出了一种新型协作干扰传输方案,以提高该系统的安全性。在第一时隙,基站将混合信号进行广播,同时为了干扰窃听者,信道条件较差的...针对协作非正交多址接入(Non-orthogonal Multiple Access,NOMA)系统中用户充当中继并存在窃听者的场景,提出了一种新型协作干扰传输方案,以提高该系统的安全性。在第一时隙,基站将混合信号进行广播,同时为了干扰窃听者,信道条件较差的用户采用全双工的工作模式,发出协作干扰信号对窃听者进行干扰。在第二时隙,信道条件较好的用户充当中继将己解码的信息转发给信道条件较差的用户,同时信道条件较差的用户继续发出协作干扰信号以干扰窃听者。充当中继的用户由于功耗过大可能会引起该节点供能不足,因此对该节点引入无线携能(Simultaneous Wireless Information and Power Transfer,SWIPT)技术构成SWIPT-NOMA系统。为了衡量针对SWIPT-NOMA系统所提出的新型传输方案的安全性能,推导了用户的保密中断概率的表达式并仿真验证了该方案的有效性。展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 62171187the Guangdong Basic and Applied Basic Research Foundation under Grant 2022A1515011476+1 种基金the Science and Technology Program of Guangzhou under Grant 201904010373the Key Program of Marine Economy Development (Six Marine Industries) Special Foundation of Department of Natural Resources of Guangdong Province (GDNRC [2020]009)。
文摘Wireless information and power transfer(WIPT) enables simultaneously communications and sustainable power supplement without the erection of power supply lines and the replacement operation of the batteries for the terminals. The application of WIPT to the underwater acoustic sensor networks(UWASNs) not only retains the long range communication capabilities, but also provides an auxiliary and convenient energy supplement way for the terminal sensors, and thus is a promising scheme to solve the energy-limited problem for the UWASNs. In this paper, we propose the integration of WIPT into the UWASNs and provide an overview on various enabling techniques for the WIPT based UWASNs(WIPT-UWASNs) as well as pointing out future research challenges and opportunities for WIPT-UWASNs.
基金supported in part by China High-Tech RD Program(863 Program) SS2015AA011306National Natural Science Foundation of China under Grants No.61379006,61401510,61501516,61521003
文摘This paper studies a simultaneous wireless information and power transfer system with multiple external eavesdroppers and internal curious users.We model the random network by Poisson cluster process in consideration of the case where eavesdroppers hide around certain targets.Focusing on the users that work in harvesting-transmitting mode with time switching receivers,we establish communication model via time division multiple access.On this basis,we propose a lightweight secure transmission scheme based on dual-thresholds for physical-layer security enhancement,which consists of two protocols applied to the downlink(DL) and uplink(UL) transmission respectively.In the DL,we design a dynamic information-power switching transmission protocol based on signal-to-noise ratio threshold,which provides an opportunistic approach to reform the fixed period allocation of information and power transfer;in the UL,an energy threshold is proposed for users to control the transmission,which is called a user-led on-off transmission protocol.Furthermore,we give a comprehensive performance analysis for the proposed scheme in terms of delay,reliability,security and secrecy throughput.Based on the analysis results,we optimize the two thresholds and the DL-UL allocationcoefficient to maximize the secrecy throughput.Simulation results show the proposed scheme can bring about a substantial secrecy gain.
基金the collaborative research program from the Microwave Energy Transmission Laboratory(METLAB)Research Insti⁃tute for Sustainable Humanosphere(RISH)Kyoto University and National Institute of Information and Communications Technology(NICT),JAPAN under Grant No.02401.
文摘Applications using simultaneous wireless information and power transfer(SWIPT)have increased significantly.Wireless communication technologies can be combined with the Internet of Things to develop many innovative applications using SWIPT,which is mainly based on wireless energy harvesting from electromagnetic waves used in communications.Wireless power transfer that uses magnetrons has been developed for communication technologies.Injection-locked magnetrons that can be used to facilitate high-power SWIPT for several devices are reviewed in this paper.This new technology is expected to pave the way for promoting the application of SWIPT in a wide range of fields.
基金the National Key Research and Development Program of China under Grant Nos.2017YFA0700201,2017YFA0700202,2017YFA0700203,and 2021YFA1401001the 111 Project under Grant No.111⁃2⁃05,National Natural Science Foundation of China under Grant No.62001342+1 种基金Key Research and Development Program of Shaanxi under Grant No.2021TD⁃07Outstanding Youth Science Foundation of Shaanxi Province under Grant No.2019JC⁃15.
文摘Implementing self-sustainable wireless communication systems is urgent and challenging for 5G and 6G technologies.In this paper,we elaborate on a system solution using the programmable metasurface(PMS)for simultaneous wireless information and power transfers(SWIPT),offering an optimized wireless energy management network.Both transmitting and receiving sides of the proposed solution are presented in detail.On the transmitting side,employing the wireless power transfer(WPT)technique,we present versatile power conveying strategies for near-field or far-field targets,single or multiple targets,and equal or unequal power targets.On the receiving side,utilizing the wireless energy harvesting(WEH)technique,we report our work on multi-functional rectifying metasurfaces that collect the wirelessly transmitted energy and the ambient energy.More importantly,a numerical model based on the plane-wave angular spectrum method is investigated to accurately calculate the radiation fields of PMS in the Fresnel and Fraunhofer regions.With this model,the efficiencies of WPT between the transmitter and the receiver are analyzed.Finally,future research directions are discussed,and integrated PMS for wireless information and wireless power is outlined.
文摘无小区大规模多输入多输出(Multiple-Input Multiple-Output,MIMO)与非正交多址接入(Non-Orthogonal Multiple Access,NOMA)都是未来6G的使能技术。无线携能通信(Simultaneous Wireless Information and Power Transfer,SWIPT)技术在进行信息解码的同时收集能量,与无小区大规模MIMO-NOMA优势互补。文中基于SWIPT研究无小区大规模MIMO-NOMA系统中的能量效率问题,通过联合优化功率分配系数和SWIPT的时隙切换(Time Switching,TS)系数,提高系统的能量效率。为了最大化能量效率,采用布谷鸟算法设计功率分配系数。考虑一种特殊情况,将所有终端的TS系数设置相同,进而推导了最佳TS系数的封闭表达式。仿真结果表明,相较于几种已有方案,文中提出的优化方案可以显著提升系统的能量效率。
基金financial support of Natural Science Foundation of China(No.61971102,62132004)MOST Major Research and Development Project(No.2021YFB2900204)+1 种基金Sichuan Science and Technology Program(No.2022YFH0022)Key Research and Development Program of Zhejiang Province(No.2022C01093)。
文摘Integrated data and energy transfer(IDET)is capable of simultaneously delivering on-demand data and energy to low-power Internet of Everything(Io E)devices.We propose a multi-carrier IDET transceiver relying on superposition waveforms consisting of multi-sinusoidal signals for wireless energy transfer(WET)and orthogonal-frequency-divisionmultiplexing(OFDM)signals for wireless data transfer(WDT).The outdated channel state information(CSI)in aging channels is employed by the transmitter to shape IDET waveforms.With the constraints of transmission power and WDT requirement,the amplitudes and phases of the IDET waveform at the transmitter and the power splitter at the receiver are jointly optimised for maximising the average directcurrent(DC)among a limited number of transmission frames with the existence of carrier-frequencyoffset(CFO).For the amplitude optimisation,the original non-convex problem can be transformed into a reversed geometric programming problem,then it can be effectively solved with existing tools.As for the phase optimisation,the artificial bee colony(ABC)algorithm is invoked in order to deal with the nonconvexity.Iteration between the amplitude optimisation and phase optimisation yields our joint design.Numerical results demonstrate the advantage of our joint design for the IDET waveform shaping with the existence of the CFO and the outdated CSI.
基金supported by the National Natural Science Foundation of China (No. 61971077)the Natural Science Foundation of Chongqing, China (No. cstc2021jcyj-msxmX0458)+3 种基金the open research fund of National Mobile Communications Research Laboratory, Southeast University (No. 2022D06)the Fundamental Research Funds for the Central Universities (No. 2020CDCGTX074)the Natural Science Foundation on Frontier Leading Technology Basic Research Project of Jiangsu (No. BK20212001)the Natural Science Research Project of Jiangsu Higher Education Institutions (No. 21KJB510034)。
文摘Micro-UAV swarms usually generate massive data when performing tasks. These data can be harnessed with various machine learning(ML) algorithms to improve the swarm’s intelligence. To achieve this goal while protecting swarm data privacy, federated learning(FL) has been proposed as a promising enabling technology. During the model training process of FL, the UAV may face an energy scarcity issue due to the limited battery capacity. Fortunately, this issue is potential to be tackled via simultaneous wireless information and power transfer(SWIPT). However, the integration of SWIPT and FL brings new challenges to the system design that have yet to be addressed, which motivates our work. Specifically,in this paper, we consider a micro-UAV swarm network consisting of one base station(BS) and multiple UAVs, where the BS uses FL to train an ML model over the data collected by the swarm. During training, the BS broadcasts the model and energy simultaneously to the UAVs via SWIPT, and each UAV relies on its harvested and battery-stored energy to train the received model and then upload it to the BS for model aggregation. To improve the learning performance, we formulate a problem of maximizing the percentage of scheduled UAVs by jointly optimizing UAV scheduling and wireless resource allocation. The problem is a challenging mixed integer nonlinear programming problem and is NP-hard in general. By exploiting its special structure property, we develop two algorithms to achieve the optimal and suboptimal solutions, respectively. Numerical results show that the suboptimal algorithm achieves a near-optimal performance under various network setups, and significantly outperforms the existing representative baselines. considered.
基金supported in part by the National Natural Science Foundation of China under Grant 62201451in part by the Young Talent fund of University Association for Science and Technology in Shaanxi under Grant 20210121+1 种基金in part by the Shaanxi provincial special fund for Technological innovation guidance(2022CGBX-29)in part by BUPT Excellent Ph.D.Students Foundation under Grant CX2022106.
文摘This paper investigates the system outage performance of a simultaneous wireless information and power transfer(SWIPT)based two-way decodeand-forward(DF)relay network,where potential hardware impairments(HIs)in all transceivers are considered.After harvesting energy and decoding messages simultaneously via a power splitting scheme,the energy-limited relay node forwards the decoded information to both terminals.Each terminal combines the signals from the direct and relaying links via selection combining.We derive the system outage probability under independent but non-identically distributed Nakagami-m fading channels.It reveals an overall system ceiling(OSC)effect,i.e.,the system falls in outage if the target rate exceeds an OSC threshold that is determined by the levels of HIs.Furthermore,we derive the diversity gain of the considered network.The result reveals that when the transmission rate is below the OSC threshold,the achieved diversity gain equals the sum of the shape parameter of the direct link and the smaller shape parameter of the terminalto-relay links;otherwise,the diversity gain is zero.This is different from the amplify-and-forward(AF)strategy,under which the relaying links have no contribution to the diversity gain.Simulation results validate the analytical results and reveal that compared with the AF strategy,the SWIPT based two-way relaying links under the DF strategy are more robust to HIs and achieve a lower system outage probability.
文摘针对有源可重构智能表面(reconfigurable intelligent surface,RIS)辅助的同步无线信息与能量传输(simultaneous wireless information and power transfer,SWIPT)系统,提出了一种考虑公平性的能量资源采集分配算法,以解决因乘性衰落导致的公平性能量采集性能较差的问题。在有源RIS辅助的SWIPT系统采用功率切割架构实现信息与能量的同步传输,构建了以所有用户中最小的采集能量最大化为目标函数,用户信干噪比、有源RIS和基站发射功率、功率划分因子等满足需求为约束条件的联合资源分配问题。利用交替优化、半正定松弛、连续凸近似、罚函数等技术将不能直接解决的非凸问题转换成标准凸问题,提出了一种交替迭代的公平性采集能量算法。数值仿真结果表明,所提优化算法能够显著提高用户中能量资源分配最少的用户处采集到的能量值,保障通信网络中能量资源分配的公平性。
基金FCT/MCTES through national funds and EU funds under the project UIDB/50008/2020⁃UIDP/50008/2020Lisboa 2020 Programme,Centro 2020 programme,Portugal 2020,Euro⁃pean Union,through the European Social Fund who sup⁃ported LISBOA-05-3559-FSE-000007 and CENTRO-04-3559-FSE-000094 operations as well as to Fundação para a Ciência e Tecnologia(FCT)and Agência Nacional de Inovação(ANI).
文摘From a circuit implementation perspective,this paper presents a brief overview of simultaneous wireless information and power transmission(SWIPT).By using zero-power batteryless wireless sensors,SWIPT mixes wireless power transmission with wireless communications to allow the truly practical implementation of the Internet of Things as well as many other applications.In this paper,technical backgrounds,problem formation,state-of-the-art solutions,circuit implementation examples,and system integrations of SWIPT are presented.
基金supported by the National Natural Science Foundation of China 62001051.
文摘Wireless Power Transfer(WPT)technology can provide real-time power for many terminal devices in Internet of Things(IoT)through millimeterWave(mmWave)to support applications with large capacity and low latency.Although the intelligent reflecting surface(IRS)can be adopted to create effective virtual links to address the mmWave blockage problem,the conventional solutions only adopt IRS in the downlink from the Base Station(BS)to the users to enhance the received signal strength.In practice,the reflection of IRS is also applicable to the uplink to improve the spectral efficiency.It is a challenging to jointly optimize IRS beamforming and system resource allocation for wireless energy acquisition and information transmission.In this paper,we first design a Low-Energy Adaptive Clustering Hierarchy(LEACH)clustering protocol for clustering and data collection.Then,the problem of maximizing the minimum system spectral efficiency is constructed by jointly optimizing the transmit power of sensor devices,the uplink and downlink transmission times,the active beamforming at the BS,and the IRS dynamic beamforming.To solve this non-convex optimization problem,we propose an alternating optimization(AO)-based joint solution algorithm.Simulation results show that the use of IRS dynamic beamforming can significantly improve the spectral efficiency of the system,and ensure the reliability of equipment communication and the sustainability of energy supply under NLOS link.
文摘针对能量受限多中继网络的物理层安全中断性能问题,提出了基于无线携能通信(Simultaneous Wireless Information and Power Transfer,SWIPT)的多中继网络物理层安全传输方案。该方案在中继节点处采用中继选择策略以及混合功率和时间分割协议来实现网络安全速率最大化。对于提出的网络安全中断性能问题,首先计算出任意链路的安全中断概率闭合表达式,然后利用瑞利衰落信道的独立性和高斯切比雪夫等式,推导出了网络安全中断概率闭合表达式。为了进一步分析理论结果,推导出了在高发射功率下的网络安全中断概率闭合表达式。仿真结果验证了理论分析的正确性。仿真结果表明,增加网络中继节点数量可以显著地降低网络安全中断概率。与功率分割协议和时间切换协议相比,低发射功率下采用混合功率分割和时间转换协议能有效地提高网络安全中断性能。
文摘以智能反射面(intelligent reflecting surface,IRS)辅助的无线携能通信(simultaneous wireless information and power transfer,SWIPT)系统为背景,研究了该系统中基于能效优先的多天线发送端有源波束成形与IRS无源波束成形联合设计与优化方法。以最大化接收端的最小能效为优化目标,构造在发送端功率、接收端能量阈值、IRS相移等多约束下的非线性优化问题,用交替方向乘子法(alternating direction method of multipliers,ADMM)求解。采用Dinkelbach算法转化目标函数,通过奇异值分解(singular value decomposition,SVD)和半定松弛(semi-definite relaxation,SDR)得到发送端有源波束成形向量。采用SDR得到IRS相移矩阵与反射波束成形向量。结果表明,该系统显著降低了系统能量收集(energy harvesting,EH)接收端的能量阈值。当系统总电路功耗为−15 dBm时,所提方案的用户能效为300 KB/J。当IRS反射阵源数与发送天线数均为最大值时,系统可达最大能效。
文摘针对协作非正交多址接入(Non-orthogonal Multiple Access,NOMA)系统中用户充当中继并存在窃听者的场景,提出了一种新型协作干扰传输方案,以提高该系统的安全性。在第一时隙,基站将混合信号进行广播,同时为了干扰窃听者,信道条件较差的用户采用全双工的工作模式,发出协作干扰信号对窃听者进行干扰。在第二时隙,信道条件较好的用户充当中继将己解码的信息转发给信道条件较差的用户,同时信道条件较差的用户继续发出协作干扰信号以干扰窃听者。充当中继的用户由于功耗过大可能会引起该节点供能不足,因此对该节点引入无线携能(Simultaneous Wireless Information and Power Transfer,SWIPT)技术构成SWIPT-NOMA系统。为了衡量针对SWIPT-NOMA系统所提出的新型传输方案的安全性能,推导了用户的保密中断概率的表达式并仿真验证了该方案的有效性。
