As the scientific data volume in deep-space exploration rapidly grows,spacecraft heavily relies on high data-rate signals that span several megahertz to transmit data back to Earth.Employing high data-rate signals for...As the scientific data volume in deep-space exploration rapidly grows,spacecraft heavily relies on high data-rate signals that span several megahertz to transmit data back to Earth.Employing high data-rate signals for high-accuracy radiometric interferometry can simultaneously deal with data transmission and spacecraft navigation.We demonstrate very long baseline interferometry(VLBI)tracking of the Chang’E-3 lander and rover to determine their relative lunar-surface position using downlink high data-rate signals.A new method based on the VLBI phase-referencing technique is proposed to obtain the differential phase delay,which is much more accurate than the differential group delay acquired by conventional VLBI approaches.The systemic errors among different signal channels have been well calibrated using the new method.The data from the Chang’E-3mission were then processed,and meter-level accuracy positions of the rover with respect to the lander have been obtained.This demonstration shows the feasibility of high-accuracy radiometric interferometry using high data-rate signals.The method proposed in this paper can also be applied to future deep-space navigation.展开更多
Due to having a large bandwidth to support Gbps-level data rate, terahertz communication attracts more and more attention in recent years. However, there are few medium access control （MAC） protocols for terahertz u...Due to having a large bandwidth to support Gbps-level data rate, terahertz communication attracts more and more attention in recent years. However, there are few medium access control （MAC） protocols for terahertz ultra-high data-rate wireless networks, which affects the research and application of terahertz communications. To address this problem and to achieve ultra-high data-rate wireless access with terahertz communication, a novel MAC protocol, called medium access control for terahertz communication （MAC-TC）, is proposed. Through designing a new channel access scheme, a new superframe structure, and related key parameters, MAC-TC can support a maximum data rate up to 10 Gbit/s even higher. Theoretical analysis and simulation results show that our proposed MAC protocol realizes the function of medium access control and attains a maximum data rate of 18.3 Gbit/s, which is 2 times higher than 5.78 Gbit/s, the theoretical maximum data rate of IEEE 802.15.3c standard.展开更多
文章设计了一种基于远距离无线电(Long Range Radio,LoRa)技术的水情信息无线传输系统,构建了感知层、网络传输层、边缘处理层和平台服务层的多层架构。文章通过低功耗多参数采集节点、自适应通信机制与边缘计算融合,实现了复杂环境下...文章设计了一种基于远距离无线电(Long Range Radio,LoRa)技术的水情信息无线传输系统,构建了感知层、网络传输层、边缘处理层和平台服务层的多层架构。文章通过低功耗多参数采集节点、自适应通信机制与边缘计算融合,实现了复杂环境下水情数据的高效获取与智能处理。系统引入轻量级抗冲突协议与边缘异常识别模型,提升了传输可靠性与响应能力。结合网络模拟器3(Network Simulator 3,NS-3)仿真平台对不同地形与节点密度下系统性能进行量化评估,结果表明该系统在典型水情场景中具备良好的通信稳定性、可扩展性与抗干扰能力,验证了其在实际部署中的可行性和实用价值。展开更多
基金supported by the Key Techniques Research Program of China’s Lunar Exploration(Grant No.TY3Q20100009)
文摘As the scientific data volume in deep-space exploration rapidly grows,spacecraft heavily relies on high data-rate signals that span several megahertz to transmit data back to Earth.Employing high data-rate signals for high-accuracy radiometric interferometry can simultaneously deal with data transmission and spacecraft navigation.We demonstrate very long baseline interferometry(VLBI)tracking of the Chang’E-3 lander and rover to determine their relative lunar-surface position using downlink high data-rate signals.A new method based on the VLBI phase-referencing technique is proposed to obtain the differential phase delay,which is much more accurate than the differential group delay acquired by conventional VLBI approaches.The systemic errors among different signal channels have been well calibrated using the new method.The data from the Chang’E-3mission were then processed,and meter-level accuracy positions of the rover with respect to the lander have been obtained.This demonstration shows the feasibility of high-accuracy radiometric interferometry using high data-rate signals.The method proposed in this paper can also be applied to future deep-space navigation.
基金supported by the National Natural Science Foundation of China (60972068)the Program for Changjiang Scholars and Innovative Research Team in University (IRT1299)+2 种基金the project of Chongqing Municipal Education Commission (Kjzh11206)the Natural Science Foundation of Chongqing (cstc2012jjA40051)the open project of Emergency Communication Laboratory of Chongqing (201201)
文摘Due to having a large bandwidth to support Gbps-level data rate, terahertz communication attracts more and more attention in recent years. However, there are few medium access control （MAC） protocols for terahertz ultra-high data-rate wireless networks, which affects the research and application of terahertz communications. To address this problem and to achieve ultra-high data-rate wireless access with terahertz communication, a novel MAC protocol, called medium access control for terahertz communication （MAC-TC）, is proposed. Through designing a new channel access scheme, a new superframe structure, and related key parameters, MAC-TC can support a maximum data rate up to 10 Gbit/s even higher. Theoretical analysis and simulation results show that our proposed MAC protocol realizes the function of medium access control and attains a maximum data rate of 18.3 Gbit/s, which is 2 times higher than 5.78 Gbit/s, the theoretical maximum data rate of IEEE 802.15.3c standard.
文摘文章设计了一种基于远距离无线电(Long Range Radio,LoRa)技术的水情信息无线传输系统,构建了感知层、网络传输层、边缘处理层和平台服务层的多层架构。文章通过低功耗多参数采集节点、自适应通信机制与边缘计算融合,实现了复杂环境下水情数据的高效获取与智能处理。系统引入轻量级抗冲突协议与边缘异常识别模型,提升了传输可靠性与响应能力。结合网络模拟器3(Network Simulator 3,NS-3)仿真平台对不同地形与节点密度下系统性能进行量化评估,结果表明该系统在典型水情场景中具备良好的通信稳定性、可扩展性与抗干扰能力,验证了其在实际部署中的可行性和实用价值。
