为解决网络安全性、数据可靠性及用户隐私性三大物联网(internet of things,IoT)可信要素问题,利用区块链技术构建泛在可信物联网系统,提出一种面向泛在可信物联网的区块链体系架构。该架构通过分层架构与跨层协同方式,有望突破区块链...为解决网络安全性、数据可靠性及用户隐私性三大物联网(internet of things,IoT)可信要素问题,利用区块链技术构建泛在可信物联网系统,提出一种面向泛在可信物联网的区块链体系架构。该架构通过分层架构与跨层协同方式,有望突破区块链不可能三角限制,解决区块链技术应用于泛在可信物联网中协议机制不匹配等问题。展开更多
Since virtualization technology enables the abstraction and sharing of resources in a flexible management way, the overall expenses of network deployment can be significantly reduced. Therefore, the technology has bee...Since virtualization technology enables the abstraction and sharing of resources in a flexible management way, the overall expenses of network deployment can be significantly reduced. Therefore, the technology has been widely applied in the core network. With the tremendous growth in mobile traffic and services, it is natural to extend virtualization technology to the cloud computing based radio access networks(CCRANs) for achieving high spectral efficiency with low cost.In this paper, the virtualization technologies in CC-RANs are surveyed, including the system architecture, key enabling techniques, challenges, and open issues. The enabling key technologies for virtualization in CC-RANs mainly including virtual resource allocation, radio access network(RAN) slicing, mobility management, and social-awareness have been comprehensively surveyed to satisfy the isolation, customization and high-efficiency utilization of radio resources. The challenges and open issues mainly focus on virtualization levels for CC-RANs, signaling design for CC-RAN virtualization, performance analysis for CC-RAN virtualization, and network security for virtualized CC-RANs.展开更多
As a promising solution to alleviating the energy bottleneck in wireless devices with limited battery capacity,simultaneous wireless information and power transfer(SWIPT)techniques have been widely researched in cellu...As a promising solution to alleviating the energy bottleneck in wireless devices with limited battery capacity,simultaneous wireless information and power transfer(SWIPT)techniques have been widely researched in cellular networks.To further improve the spectral and energy efficiency of wireless information and power transfer,the combination of SWIPT and new techniques in cellular networks has drawn much attention recently.In this paper,we comprehensively survey the key techniques for SWIPT,the combination of SWIPT and new techniques in cellular networks,challenges and open issues.The key techniques for SWIPT including traditional power splitting,time switching,etc.,and joint receiving and transmitting techniques such as eigenchannels and mixed signals are provided in detail.Furthermore,the applications of SWIPT to recent techniques such as SWIPT-assisted non-orthogonal multiple access,SWIPT-assisted device-to-device communication,and SWIPT-assisted full-duplex communication,are comprehensively summarized in this paper.The potential open issues including the management of dynamic harvested energy,trading between wireless power transfer and traffic offloading,and effects of the mode switching at energy harvesting devices,are outlined as well.展开更多
In this paper, we develop and analyze an energy efficient ARQ （automatic repeat request） initialized transmit diversity protocol for cooperative communications.Medium access control （MAC） layer packet retransmissi...In this paper, we develop and analyze an energy efficient ARQ （automatic repeat request） initialized transmit diversity protocol for cooperative communications.Medium access control （MAC） layer packet retransmission limit （similar to aShortRetryLimit or aLongRetryLimit [802.11-1997]） has been used as an actuator for transmit cooperative diversity initialization.We take the channel state information （CSI） as a function of retransmission tries and the number of retransmission tries is modeled as a random variable.Relays close to the source node are chosen for the transmit cooperation.Closed form expressions are obtained for symbol error rate （SER）, outage capacity and outage probability for the proposed scheme in shadowed fading channels.This cooperative scheme achieves lower signal-to-noise ratio （SNR）, stumpy outage probability, higher bandwidth, and transmit energy efficiencies for desired average symbol error rate （ASER） than the preceding ARQ based cooperative protocols.Finally, the results of computer simulations are included to demonstrate the efficacy of the proposed scheme and to verify the accuracy of the analytical expressions.展开更多
文摘为解决网络安全性、数据可靠性及用户隐私性三大物联网(internet of things,IoT)可信要素问题,利用区块链技术构建泛在可信物联网系统,提出一种面向泛在可信物联网的区块链体系架构。该架构通过分层架构与跨层协同方式,有望突破区块链不可能三角限制,解决区块链技术应用于泛在可信物联网中协议机制不匹配等问题。
文摘Since virtualization technology enables the abstraction and sharing of resources in a flexible management way, the overall expenses of network deployment can be significantly reduced. Therefore, the technology has been widely applied in the core network. With the tremendous growth in mobile traffic and services, it is natural to extend virtualization technology to the cloud computing based radio access networks(CCRANs) for achieving high spectral efficiency with low cost.In this paper, the virtualization technologies in CC-RANs are surveyed, including the system architecture, key enabling techniques, challenges, and open issues. The enabling key technologies for virtualization in CC-RANs mainly including virtual resource allocation, radio access network(RAN) slicing, mobility management, and social-awareness have been comprehensively surveyed to satisfy the isolation, customization and high-efficiency utilization of radio resources. The challenges and open issues mainly focus on virtualization levels for CC-RANs, signaling design for CC-RAN virtualization, performance analysis for CC-RAN virtualization, and network security for virtualized CC-RANs.
文摘As a promising solution to alleviating the energy bottleneck in wireless devices with limited battery capacity,simultaneous wireless information and power transfer(SWIPT)techniques have been widely researched in cellular networks.To further improve the spectral and energy efficiency of wireless information and power transfer,the combination of SWIPT and new techniques in cellular networks has drawn much attention recently.In this paper,we comprehensively survey the key techniques for SWIPT,the combination of SWIPT and new techniques in cellular networks,challenges and open issues.The key techniques for SWIPT including traditional power splitting,time switching,etc.,and joint receiving and transmitting techniques such as eigenchannels and mixed signals are provided in detail.Furthermore,the applications of SWIPT to recent techniques such as SWIPT-assisted non-orthogonal multiple access,SWIPT-assisted device-to-device communication,and SWIPT-assisted full-duplex communication,are comprehensively summarized in this paper.The potential open issues including the management of dynamic harvested energy,trading between wireless power transfer and traffic offloading,and effects of the mode switching at energy harvesting devices,are outlined as well.
基金Supported by the National Natral Science Foundation of China (Grant No 60602058)the National High Technology Research and Development Program of China (Grant No 2006AA01Z257)
文摘In this paper, we develop and analyze an energy efficient ARQ （automatic repeat request） initialized transmit diversity protocol for cooperative communications.Medium access control （MAC） layer packet retransmission limit （similar to aShortRetryLimit or aLongRetryLimit [802.11-1997]） has been used as an actuator for transmit cooperative diversity initialization.We take the channel state information （CSI） as a function of retransmission tries and the number of retransmission tries is modeled as a random variable.Relays close to the source node are chosen for the transmit cooperation.Closed form expressions are obtained for symbol error rate （SER）, outage capacity and outage probability for the proposed scheme in shadowed fading channels.This cooperative scheme achieves lower signal-to-noise ratio （SNR）, stumpy outage probability, higher bandwidth, and transmit energy efficiencies for desired average symbol error rate （ASER） than the preceding ARQ based cooperative protocols.Finally, the results of computer simulations are included to demonstrate the efficacy of the proposed scheme and to verify the accuracy of the analytical expressions.
