In current wireless communication and electronic systems,digital signals and electromagnetic(EM)radiation are processed by different modules.Here,we propose a mechanism to fuse the modulation of digital signals and th...In current wireless communication and electronic systems,digital signals and electromagnetic(EM)radiation are processed by different modules.Here,we propose a mechanism to fuse the modulation of digital signals and the manipulation of EM radiation on a single programmable metasurface(PM).The PM consists of massive subwavelength-scale digital coding elements.A set of digital states of all elements forms simultaneous digital information roles for modulation and the wave-control sequence code of the PM.By designing digital coding sequences in the spatial and temporal domains,the digital information and farfield patterns of the PM can be programmed simultaneously and instantly in desired ways.For the experimental demonstration of the mechanism,we present a programmable wireless communication system.The same system can realize transmissions of digital information in single-channel modes with beamsteerable capability and multichannel modes with multiple independent information.The measured results show the excellent performance of the programmable system.This work provides excellent prospects for applications in fifth-or sixth-generation wireless communications and modern intelligent platforms for unmanned aircrafts and vehicles.展开更多
The development of applications based on artificial intelligence and implemented over wireless networks is increasingly rapidly and is expected to grow dramatically in the future.The resulting demand for the aggregati...The development of applications based on artificial intelligence and implemented over wireless networks is increasingly rapidly and is expected to grow dramatically in the future.The resulting demand for the aggregation of large amounts of data has caused serious communication bottlenecks in wireless networks and particularly at the network edge.Over-the-air federated learning(OTA-FL),leveraging the superposition feature of multi-access channels,enables users at the network edge to share spectrum resources and achieves efficient and low-latency global model aggregation.This paper provides a holistic review of progress in OTA-FL and points to potential future research directions.Specifically,we classify OTA-FL from the perspective of system settings,including single-antenna OTA-FL,multi-antenna OTA-FL,and OTA-FL with the aid of the emerging reconfigurable intelligent surface technology,and the contributions of existing works in these areas are summarized.Moreover,we discuss the trust,security and privacy aspects of OTA-FL,and highlight concerns arising from security and privacy.Finally,challenges and potential research directions are discussed to promote the future development of OTA-FL in terms of improving system performance,reliability,and trustworthiness.Specifical challenges to be addressed include model distortion under channel fading,the ineffective OTA aggregation of local models trained on substantially unbalanced data,and the limited accessibility and verifiability of individual local models.展开更多
Millimeter-wave(mmWave) and massive multiple-input multiple-output(MIMO) are broadly recognized as key enabling technologies for the fifth generation(5G) communication systems. In this paper, a low-complexity angle-de...Millimeter-wave(mmWave) and massive multiple-input multiple-output(MIMO) are broadly recognized as key enabling technologies for the fifth generation(5G) communication systems. In this paper, a low-complexity angle-delay parameters estimation(ADPE) algorithm was put forward for wideband mmWave systems with uniform planar arrays(UPAs). In particular, the ADPE algorithm effectively decouples the angle-delay parameters and converts the angle-delay estimation problem into three independent subproblems. Accordingly, the ability to devise an off-grid method based on discrete Fourier transform(DFT) with a closed-form solution for angle-delay estimation and potential path number acquisition can be realized. In actuality, only a limited number of potential paths are close to the true paths influenced by noise. Consequently, the removal of noise paths to acquire the corresponding true path gains through a sparsity adaptive path gains estimation(APGE) algorithm is postulated. Finally, the simulation results substantiate the effectiveness of ADPE and APGE algorithms.展开更多
基金supported by the Fund for International Cooperation and Exchange of National Natural Science Foundation of China(61761136007)the National Key Research and Development Program of China(2017YFA0700201,2017YFA0700202,and 2017YFA0700203)+3 种基金the National Natural Science Foundation of China(6217010363,61631007,61571117,61501112,61501117,61871109,61522106,61731010,61735010,61722106,61701107,and 61701108)the Natural Science Foundation of Jiangsu Province(BK20211161)the 111 Project(111-2-05)ZhiShan Young Scholar Program of Southeast University.
文摘In current wireless communication and electronic systems,digital signals and electromagnetic(EM)radiation are processed by different modules.Here,we propose a mechanism to fuse the modulation of digital signals and the manipulation of EM radiation on a single programmable metasurface(PM).The PM consists of massive subwavelength-scale digital coding elements.A set of digital states of all elements forms simultaneous digital information roles for modulation and the wave-control sequence code of the PM.By designing digital coding sequences in the spatial and temporal domains,the digital information and farfield patterns of the PM can be programmed simultaneously and instantly in desired ways.For the experimental demonstration of the mechanism,we present a programmable wireless communication system.The same system can realize transmissions of digital information in single-channel modes with beamsteerable capability and multichannel modes with multiple independent information.The measured results show the excellent performance of the programmable system.This work provides excellent prospects for applications in fifth-or sixth-generation wireless communications and modern intelligent platforms for unmanned aircrafts and vehicles.
基金supported by the National Natural Science Foundation of China(62231010,62071126)the Innovation Program of Shanghai Municipal Science and Technology Commission(21XD1400300)the U.S National Science Foundation(CNS-2128448,ECCS-2335876).
文摘The development of applications based on artificial intelligence and implemented over wireless networks is increasingly rapidly and is expected to grow dramatically in the future.The resulting demand for the aggregation of large amounts of data has caused serious communication bottlenecks in wireless networks and particularly at the network edge.Over-the-air federated learning(OTA-FL),leveraging the superposition feature of multi-access channels,enables users at the network edge to share spectrum resources and achieves efficient and low-latency global model aggregation.This paper provides a holistic review of progress in OTA-FL and points to potential future research directions.Specifically,we classify OTA-FL from the perspective of system settings,including single-antenna OTA-FL,multi-antenna OTA-FL,and OTA-FL with the aid of the emerging reconfigurable intelligent surface technology,and the contributions of existing works in these areas are summarized.Moreover,we discuss the trust,security and privacy aspects of OTA-FL,and highlight concerns arising from security and privacy.Finally,challenges and potential research directions are discussed to promote the future development of OTA-FL in terms of improving system performance,reliability,and trustworthiness.Specifical challenges to be addressed include model distortion under channel fading,the ineffective OTA aggregation of local models trained on substantially unbalanced data,and the limited accessibility and verifiability of individual local models.
基金supported by the National Key Technology R&D Program of China (2022YFB2902302)。
文摘Millimeter-wave(mmWave) and massive multiple-input multiple-output(MIMO) are broadly recognized as key enabling technologies for the fifth generation(5G) communication systems. In this paper, a low-complexity angle-delay parameters estimation(ADPE) algorithm was put forward for wideband mmWave systems with uniform planar arrays(UPAs). In particular, the ADPE algorithm effectively decouples the angle-delay parameters and converts the angle-delay estimation problem into three independent subproblems. Accordingly, the ability to devise an off-grid method based on discrete Fourier transform(DFT) with a closed-form solution for angle-delay estimation and potential path number acquisition can be realized. In actuality, only a limited number of potential paths are close to the true paths influenced by noise. Consequently, the removal of noise paths to acquire the corresponding true path gains through a sparsity adaptive path gains estimation(APGE) algorithm is postulated. Finally, the simulation results substantiate the effectiveness of ADPE and APGE algorithms.
