With the large-scale commercial launch of fifth generation(5G)mobile network,the development of new services and applications catering to the year 2030,along with the deep convergence of information,communication,and ...With the large-scale commercial launch of fifth generation(5G)mobile network,the development of new services and applications catering to the year 2030,along with the deep convergence of information,communication,and data technologies(ICDT),and the lessons and experiences from 5G practice will drive the evolution of the next generation of mobile networks.This article surveys the history and driving forces of the evolution of the mobile network architecture and proposes a logical function architecture for sixth generation(6G)mobile network.The proposed 6G network architecture is termed SOLIDS(related to the following basic features:soft,on-demand fulfillment,lite,native intelligence,digital twin,and native security),which can support self-generation,self-healing,self-evolution,and self-immunity without human involvement and address the primary issues in the legacy 5G network(e.g.,high cost,high power consumption,and highly complicated operation and maintenance),significantly well.展开更多
With the commercialization of fifth generation networks worldwide,research into sixth generation(6G)networks has been launched to meet the demands for high data rates and low latency for future services.A wireless pro...With the commercialization of fifth generation networks worldwide,research into sixth generation(6G)networks has been launched to meet the demands for high data rates and low latency for future services.A wireless propagation channel is the transmission medium to transfer information between the transmitter and the receiver.Moreover,channel properties determine the ultimate performance limit of wireless communication systems.Thus,conducting channel research is a prerequisite to designing 6G wireless communication systems.In this paper,we first introduce several emerging technologies and applications for 6G,such as terahertz communication,industrial Internet of Things,space-air-ground integrated network,and machine learning,and point out the developing trends of 6G channel models.Then,we give a review of channel measurements and models for the technologies and applications.Finally,the outlook for 6G channel measurements and models is discussed.展开更多
Thanks to the recent advances in metamaterials,Reconfigurable Intelligent Surface(RIS)has emergedas a promising technology for future 6G wireless communications.Benefiting from its high array gain,low cost,and low pow...Thanks to the recent advances in metamaterials,Reconfigurable Intelligent Surface(RIS)has emergedas a promising technology for future 6G wireless communications.Benefiting from its high array gain,low cost,and low power consumption,RISs are expected to greatly enlarge signal coverage,improve system capacity,andincrease energy efficiency.In this article,we systematically overview the emerging RIS technology with the focuson its key basics,nine fundamental issues,and one critical problem.Specifically,we first explain the RIS basics,including its working principles,hardware structures,and potential benefits for communications.Based on thesebasics,nine fundamental issues of RISs,such as“What’s the differences between RISs and massive MIMO?”and“Is RIS really intelligent?”,are explicitly addressed to elaborate its technical features,distinguish it from existingtechnologies,and clarify some misunderstandings in the literature.Then,one critical problem of RISs is revealedthat,due to the“multiplicative fading”effect,existing passive RISs can hardly achieve visible performance gains inmany communication scenarios with strong direct links.To address this critical problem,a potential solution calledactive RISs is introduced,and its effectiveness is demonstrated by numerical simulations.展开更多
Intent-Based Networks(IBNs),which are originally proposed to introduce Artificial Intelligence(AI)into the sixth-generation(6G)wireless networks,can effectively solve the challenges of traditional networks in terms of...Intent-Based Networks(IBNs),which are originally proposed to introduce Artificial Intelligence(AI)into the sixth-generation(6G)wireless networks,can effectively solve the challenges of traditional networks in terms of efficiency,flexibility,and security.IBNs are mainly used to transform users’business intent into network configuration,operation,and maintenance strategies,which are prominent for designing the AI-enabled 6G networks.In particular,in order to meet the massive,intelligent service demands and overcome the time-varying radio propagation,IBNs can continuously learn and adapt to the time-varying network environment based on the massive collected network data in real-time.From the aspects of both the core network and radio access network,this article comprehensively surveys the architectures and key techniques of IBNs for 6G.In particular,the demonstration platforms of IBNs,such as the Apstra Operating System,Forward Networks Verification Platform,and One Convergence Service Interaction Platform,are presented.Moreover,the industrial development of IBNs is elaborated,including the emerging new products and startups to solve the problems of open data platforms,automated network operations,and preemptive network fault diagnosis.Finally,several open issues and challenges are identified as well to spur future researches.展开更多
In the upcoming sixth-generation(6G)era,the demand for constructing a wide-area time-sensitive Internet of Things(IoT)continues to increase.As conventional cellular technologies are difficult to directly use for wide-...In the upcoming sixth-generation(6G)era,the demand for constructing a wide-area time-sensitive Internet of Things(IoT)continues to increase.As conventional cellular technologies are difficult to directly use for wide-area time-sensitive IoT,it is beneficial to use non-terrestrial infrastructures,including satellites and unmanned aerial vehicles(UAVs).Thus,we can build a non-terrestrial network(NTN)using a cell-free architecture.Driven by the time-sensitive requirements and uneven distribution of IoT devices,the NTN must be empowered using mobile edge computing(MEC)while providing oasisoriented on-demand coverage for devices.Nevertheless,communication and MEC systems are coupled with each other under the influence of a complex propagation environment in the MEC-empowered NTN,which makes it difficult to coordinate the resources.In this study,we propose a process-oriented framework to design communication and MEC systems in a time-division manner.In this framework,large-scale channel state information(CSI)is used to characterize the complex propagation environment at an affordable cost,where a nonconvex latency minimization problem is formulated.Subsequently,the approximated problem is provided,and it can be decomposed into sub-problems.These sub-problems are then solved iteratively.The simulation results demonstrated the superiority of the proposed process-oriented scheme over other algorithms,implied that the payload deployments of UAVs should be appropriately predesigned to improve the efficiency of using resources,and confirmed that it is advantageous to integrate NTN with MEC for wide-area time-sensitive IoT.展开更多
Russian writer Nicholas Tempered （1934） provided generations Ostrovski＇s novel How the Steel Was of Chinese youth with a widely admired role model： a young devoted communist soldier, Pawel Korchagin, whose image o...Russian writer Nicholas Tempered （1934） provided generations Ostrovski＇s novel How the Steel Was of Chinese youth with a widely admired role model： a young devoted communist soldier, Pawel Korchagin, whose image occupied a prominent place in the orthodoxy revolutionary education and literary imagination during Mao＇s era. Over the past decade, Pawel Korchagin has regained his popularity in Chinese media, his name and image have been appropriated by numerous artists and filmmakers to help in portrayals of the new generation＇s self-fashioning. The various （unorthodox） interpretations recently attached to Pawel＇s heroic story reveal a huge gap between Maoist ideology and the post-Mao ideas. This paper looks into the intricate relationships between Pawel Korchagin＇s revolutionary past and his varied contemporary representations. By doing so, I hope to gain a better understanding of the cultural politics of appropriating Mao＇s legacy to create new meanings for a changing Chinese society One example on which this paper focuses is the sixth-generation director Lu Xuechang＇s film Becoming a Man （1997）, which rewrites the revolutionary Bildungsroman of Pawel in a startling different context.展开更多
Aerial access networks have been envisioned as a promising 6G solution to enhance the ground communication systems in both coverage and capacity. To better utilize the spectrum and fully explore different channel char...Aerial access networks have been envisioned as a promising 6G solution to enhance the ground communication systems in both coverage and capacity. To better utilize the spectrum and fully explore different channel characteristics, this paper constructs an integrated network comprising the High Altitude Platform(HAP) and Unmanned Air Vehicles(UAVs) with the NonOrthogonal Multiple Access(NOMA) technology. In order to improve the transmission quality of images and videos, a power management scheme is proposed to minimize the distortion of the transmissions from the HAP and UAVs to the terminals. The power control is formulated as a non-convex problem constrained by the maximal transmit power and the minimal terminal rate requirements. The variable substitution and the first-order Tailor’s expansion is used to transform it into a sequence of convex problems, which are subsequently solved through the gradient projection method. Simulation demonstrates the signal distortion and error rate improvement achieved by the proposed algorithm.展开更多
Simultaneously transmitting and reflecting reconfigurable intelligent surfaces(STAR-RISs)have been attracting significant attention in both academia and industry for their advantages of achieving 360°coverage and...Simultaneously transmitting and reflecting reconfigurable intelligent surfaces(STAR-RISs)have been attracting significant attention in both academia and industry for their advantages of achieving 360°coverage and enhanced degrees-of-freedom.This article first identifies the fundamentals of STAR-RIS,by discussing the hardware models,channel models,and signal models.Then,three representative categorizing approaches for STAR-RISs are introduced from the phase-shift,directional,and energy consumption perspectives.Furthermore,the beamforming design of STAR-RISs is investigated for both independent and coupled phase-shift cases.As a recent advance,a general optimization framework,which has high compatibility and provable optimality regardless of the application scenarios,is proposed.As a further advance,several promising applications are discussed to demonstrate the potential benefits of applying STAR-RISs in sixth-generation wireless communication.Lastly,a few future directions and research opportunities are highlighted.展开更多
基金the National Key Research and Development Program of China(2020YFB1806800).
文摘With the large-scale commercial launch of fifth generation(5G)mobile network,the development of new services and applications catering to the year 2030,along with the deep convergence of information,communication,and data technologies(ICDT),and the lessons and experiences from 5G practice will drive the evolution of the next generation of mobile networks.This article surveys the history and driving forces of the evolution of the mobile network architecture and proposes a logical function architecture for sixth generation(6G)mobile network.The proposed 6G network architecture is termed SOLIDS(related to the following basic features:soft,on-demand fulfillment,lite,native intelligence,digital twin,and native security),which can support self-generation,self-healing,self-evolution,and self-immunity without human involvement and address the primary issues in the legacy 5G network(e.g.,high cost,high power consumption,and highly complicated operation and maintenance),significantly well.
基金supported by the National Key R&D Program of China(No.2018YFB1801101)the National Science Fund for Distinguished Young Scholars,China(No.61925102)the Key Project of State Key Lab of Networking and Switching Technology,China(No.NST20180105),Huawei,and ZTE Corporation。
文摘With the commercialization of fifth generation networks worldwide,research into sixth generation(6G)networks has been launched to meet the demands for high data rates and low latency for future services.A wireless propagation channel is the transmission medium to transfer information between the transmitter and the receiver.Moreover,channel properties determine the ultimate performance limit of wireless communication systems.Thus,conducting channel research is a prerequisite to designing 6G wireless communication systems.In this paper,we first introduce several emerging technologies and applications for 6G,such as terahertz communication,industrial Internet of Things,space-air-ground integrated network,and machine learning,and point out the developing trends of 6G channel models.Then,we give a review of channel measurements and models for the technologies and applications.Finally,the outlook for 6G channel measurements and models is discussed.
基金supported by the National Key Research and Development Program of China(No.2020YFB1805005)the National Natural Science Foundation of China(No.62031019)the European Commission through the H2020-MSCA-ITN META WIRELESS Research Project(No.956256)。
文摘Thanks to the recent advances in metamaterials,Reconfigurable Intelligent Surface(RIS)has emergedas a promising technology for future 6G wireless communications.Benefiting from its high array gain,low cost,and low power consumption,RISs are expected to greatly enlarge signal coverage,improve system capacity,andincrease energy efficiency.In this article,we systematically overview the emerging RIS technology with the focuson its key basics,nine fundamental issues,and one critical problem.Specifically,we first explain the RIS basics,including its working principles,hardware structures,and potential benefits for communications.Based on thesebasics,nine fundamental issues of RISs,such as“What’s the differences between RISs and massive MIMO?”and“Is RIS really intelligent?”,are explicitly addressed to elaborate its technical features,distinguish it from existingtechnologies,and clarify some misunderstandings in the literature.Then,one critical problem of RISs is revealedthat,due to the“multiplicative fading”effect,existing passive RISs can hardly achieve visible performance gains inmany communication scenarios with strong direct links.To address this critical problem,a potential solution calledactive RISs is introduced,and its effectiveness is demonstrated by numerical simulations.
基金This work was supported in part by the State Major Science and Technology Special Project(Grant No.2018ZX03001002-004 and 2018ZX03001023)the National Natural Science Foundation of China under No.61921003,61925101,61831002,and 61901044+1 种基金the Beijing Natural Science Foundation under No.JQ18016and the National Program for Special Support of Eminent Professionals.
文摘Intent-Based Networks(IBNs),which are originally proposed to introduce Artificial Intelligence(AI)into the sixth-generation(6G)wireless networks,can effectively solve the challenges of traditional networks in terms of efficiency,flexibility,and security.IBNs are mainly used to transform users’business intent into network configuration,operation,and maintenance strategies,which are prominent for designing the AI-enabled 6G networks.In particular,in order to meet the massive,intelligent service demands and overcome the time-varying radio propagation,IBNs can continuously learn and adapt to the time-varying network environment based on the massive collected network data in real-time.From the aspects of both the core network and radio access network,this article comprehensively surveys the architectures and key techniques of IBNs for 6G.In particular,the demonstration platforms of IBNs,such as the Apstra Operating System,Forward Networks Verification Platform,and One Convergence Service Interaction Platform,are presented.Moreover,the industrial development of IBNs is elaborated,including the emerging new products and startups to solve the problems of open data platforms,automated network operations,and preemptive network fault diagnosis.Finally,several open issues and challenges are identified as well to spur future researches.
基金the National Key R&D Program of China(2018YFA0701601 and 2020YFA0711301)the National Natural Science Foundation of China(61771286,61941104,and 61922049)the Tsinghua University-China Mobile Communications Group Co.,Ltd.Joint Institute.
文摘In the upcoming sixth-generation(6G)era,the demand for constructing a wide-area time-sensitive Internet of Things(IoT)continues to increase.As conventional cellular technologies are difficult to directly use for wide-area time-sensitive IoT,it is beneficial to use non-terrestrial infrastructures,including satellites and unmanned aerial vehicles(UAVs).Thus,we can build a non-terrestrial network(NTN)using a cell-free architecture.Driven by the time-sensitive requirements and uneven distribution of IoT devices,the NTN must be empowered using mobile edge computing(MEC)while providing oasisoriented on-demand coverage for devices.Nevertheless,communication and MEC systems are coupled with each other under the influence of a complex propagation environment in the MEC-empowered NTN,which makes it difficult to coordinate the resources.In this study,we propose a process-oriented framework to design communication and MEC systems in a time-division manner.In this framework,large-scale channel state information(CSI)is used to characterize the complex propagation environment at an affordable cost,where a nonconvex latency minimization problem is formulated.Subsequently,the approximated problem is provided,and it can be decomposed into sub-problems.These sub-problems are then solved iteratively.The simulation results demonstrated the superiority of the proposed process-oriented scheme over other algorithms,implied that the payload deployments of UAVs should be appropriately predesigned to improve the efficiency of using resources,and confirmed that it is advantageous to integrate NTN with MEC for wide-area time-sensitive IoT.
文摘Russian writer Nicholas Tempered （1934） provided generations Ostrovski＇s novel How the Steel Was of Chinese youth with a widely admired role model： a young devoted communist soldier, Pawel Korchagin, whose image occupied a prominent place in the orthodoxy revolutionary education and literary imagination during Mao＇s era. Over the past decade, Pawel Korchagin has regained his popularity in Chinese media, his name and image have been appropriated by numerous artists and filmmakers to help in portrayals of the new generation＇s self-fashioning. The various （unorthodox） interpretations recently attached to Pawel＇s heroic story reveal a huge gap between Maoist ideology and the post-Mao ideas. This paper looks into the intricate relationships between Pawel Korchagin＇s revolutionary past and his varied contemporary representations. By doing so, I hope to gain a better understanding of the cultural politics of appropriating Mao＇s legacy to create new meanings for a changing Chinese society One example on which this paper focuses is the sixth-generation director Lu Xuechang＇s film Becoming a Man （1997）, which rewrites the revolutionary Bildungsroman of Pawel in a startling different context.
基金supported by the National Natural Science Foundation of China(61901115,62171188)。
文摘Aerial access networks have been envisioned as a promising 6G solution to enhance the ground communication systems in both coverage and capacity. To better utilize the spectrum and fully explore different channel characteristics, this paper constructs an integrated network comprising the High Altitude Platform(HAP) and Unmanned Air Vehicles(UAVs) with the NonOrthogonal Multiple Access(NOMA) technology. In order to improve the transmission quality of images and videos, a power management scheme is proposed to minimize the distortion of the transmissions from the HAP and UAVs to the terminals. The power control is formulated as a non-convex problem constrained by the maximal transmit power and the minimal terminal rate requirements. The variable substitution and the first-order Tailor’s expansion is used to transform it into a sequence of convex problems, which are subsequently solved through the gradient projection method. Simulation demonstrates the signal distortion and error rate improvement achieved by the proposed algorithm.
基金Project supported by CHIST-ERA(SUNRISE CHIST-ERA-20-SICT-005)the Engineering and Physical Sciences Research Council(No.EP/W035588/1)the PHC Alliance Franco-British Joint Research Programme(No.822326028)。
文摘Simultaneously transmitting and reflecting reconfigurable intelligent surfaces(STAR-RISs)have been attracting significant attention in both academia and industry for their advantages of achieving 360°coverage and enhanced degrees-of-freedom.This article first identifies the fundamentals of STAR-RIS,by discussing the hardware models,channel models,and signal models.Then,three representative categorizing approaches for STAR-RISs are introduced from the phase-shift,directional,and energy consumption perspectives.Furthermore,the beamforming design of STAR-RISs is investigated for both independent and coupled phase-shift cases.As a recent advance,a general optimization framework,which has high compatibility and provable optimality regardless of the application scenarios,is proposed.As a further advance,several promising applications are discussed to demonstrate the potential benefits of applying STAR-RISs in sixth-generation wireless communication.Lastly,a few future directions and research opportunities are highlighted.
