舰船不同位置处的各装备基准面之间的相对水平度测量需要使用相对水平度无线差分系统。分析了相对水平度无线差分测量系统各水平度测量节点对时精度需求,研究阐述了精确时钟同步协议(Procision Time Protocol,PTP)1588协议的工作原理、...舰船不同位置处的各装备基准面之间的相对水平度测量需要使用相对水平度无线差分系统。分析了相对水平度无线差分测量系统各水平度测量节点对时精度需求,研究阐述了精确时钟同步协议(Procision Time Protocol,PTP)1588协议的工作原理、时钟模型和延时测量机制。在该协议分析研究的基础上,结合相对水平度无线差分测量系统的网络特点和对时精度需求,分析了PTP 1588在相对水平度无线差分测量系统网络应用的关键点,选取合适的机制和参数,对报文格式、主从结构等进行针对性设计,构建了针对此特定应用的高精度时间对时方案,并进行了误差因素分析。展开更多
It is extensively approved that Channel State Information(CSI) plays an important role for synergetic transmission and interference management. However, pilot overhead to obtain CSI with enough precision is a signific...It is extensively approved that Channel State Information(CSI) plays an important role for synergetic transmission and interference management. However, pilot overhead to obtain CSI with enough precision is a significant issue for wireless communication networks with massive antennas and ultra-dense cell. This paper proposes a learning- based channel model, which can estimate, refine, and manage CSI for a synergetic transmission system. It decomposes the channel impulse response into multiple paths, and uses a learning-based algorithm to estimate paths' parameters without notable degradation caused by sparse pilots. Both indoor measurement and outdoor measurement are conducted to verify the feasibility of the proposed channel model preliminarily.展开更多
This study focused on differences in vehicle-to-vehicle radio channel character- istics in the same region but different traffic density and speeds at 5.9 GHz （congestion and non-congestion）. The continuous measurem...This study focused on differences in vehicle-to-vehicle radio channel character- istics in the same region but different traffic density and speeds at 5.9 GHz （congestion and non-congestion）. The continuous measurement campaign was conducted on a city expressway through the complex dense urban area in Wu- hart, China. Small-scale channel characteris- tics including power delay profile, amplitude fading distribution, K-factor, delay spread and Doppler shift were obtained, respectively. Spe- cifically, the cumulative distribution function of root mean square delay spreads and root mean square Doppler spreads in the non-con- gested scenario and congested scenario were all fitted well with Lognormal distribution. We also found out that different intensity of traffic and speed of vehicles have little effect on root mean square delay spreads, but have a big im- pact on root mean square Doppler spreads and level crossing rate. According to estimation outcomes, the V2V channel characteristics for urban areas in Chinese big city were differ- ent from the previous measured results under similar scenarios in Europe. Delay spread and level crossing rate in this study can provide significant references to design the wireless communication system for vehicle-to-vehicle channel.展开更多
文摘舰船不同位置处的各装备基准面之间的相对水平度测量需要使用相对水平度无线差分系统。分析了相对水平度无线差分测量系统各水平度测量节点对时精度需求,研究阐述了精确时钟同步协议(Procision Time Protocol,PTP)1588协议的工作原理、时钟模型和延时测量机制。在该协议分析研究的基础上,结合相对水平度无线差分测量系统的网络特点和对时精度需求,分析了PTP 1588在相对水平度无线差分测量系统网络应用的关键点,选取合适的机制和参数,对报文格式、主从结构等进行针对性设计,构建了针对此特定应用的高精度时间对时方案,并进行了误差因素分析。
基金supported by National Basic Research Program of China (NO 2012CB316002)China’s 863 Project (NO 2014AA01A703)+2 种基金National Major Projec (NO. 2014ZX03003002-002)Program for New Century Excellent Talents in University (NCET-13-0321)Tsinghua University Initiative Scientific Research Program (2011THZ02-2)
文摘It is extensively approved that Channel State Information(CSI) plays an important role for synergetic transmission and interference management. However, pilot overhead to obtain CSI with enough precision is a significant issue for wireless communication networks with massive antennas and ultra-dense cell. This paper proposes a learning- based channel model, which can estimate, refine, and manage CSI for a synergetic transmission system. It decomposes the channel impulse response into multiple paths, and uses a learning-based algorithm to estimate paths' parameters without notable degradation caused by sparse pilots. Both indoor measurement and outdoor measurement are conducted to verify the feasibility of the proposed channel model preliminarily.
基金supported by Norwegian Research Council(No.256309)supported by an International Cooperation Project:5G-Channel Measurement and Channel Modeling for Ocean Scenario(No.20172h0046)+3 种基金Hubei college excellent young science and technology innovation team project:Fast Varying Channel Modeling and Analysis(No.T201736)Young Scientists Found of National Natural Science Foundation of China(No.61701356)Fundamental Research Funds for the Central Universities(No.2017-JL-004)(China Scholarship Council) CSC agency for funding and the Super Radio AS
文摘This study focused on differences in vehicle-to-vehicle radio channel character- istics in the same region but different traffic density and speeds at 5.9 GHz （congestion and non-congestion）. The continuous measurement campaign was conducted on a city expressway through the complex dense urban area in Wu- hart, China. Small-scale channel characteris- tics including power delay profile, amplitude fading distribution, K-factor, delay spread and Doppler shift were obtained, respectively. Spe- cifically, the cumulative distribution function of root mean square delay spreads and root mean square Doppler spreads in the non-con- gested scenario and congested scenario were all fitted well with Lognormal distribution. We also found out that different intensity of traffic and speed of vehicles have little effect on root mean square delay spreads, but have a big im- pact on root mean square Doppler spreads and level crossing rate. According to estimation outcomes, the V2V channel characteristics for urban areas in Chinese big city were differ- ent from the previous measured results under similar scenarios in Europe. Delay spread and level crossing rate in this study can provide significant references to design the wireless communication system for vehicle-to-vehicle channel.
