随着数字信号处理技术的发展,软件无线电平台显示出了其显著的特点和优越的性能,本文设计了一款通用的基于软件无线电平台的通信信号模拟器,可以实现复杂的通信信号电磁环境模拟。平台系统硬件设计主要包括现场可编程门阵列(field-progr...随着数字信号处理技术的发展,软件无线电平台显示出了其显著的特点和优越的性能,本文设计了一款通用的基于软件无线电平台的通信信号模拟器,可以实现复杂的通信信号电磁环境模拟。平台系统硬件设计主要包括现场可编程门阵列(field-programmable gate array,FPGA)、数模转换器(digital to analog convertor,DAC)芯片和时钟芯片,FPGA外挂大容量存储器DDR3设计等。平台系统软件设计包括信号调制部分和控制部分,其中信号调制部分能够实现多种通信信号的产生。控制部分主要用于解析主机软件对信号的配置和设置各类参数,并控制整个软件无线电平台协调工作。最后经实测验证,该平台能够灵活地模拟无线通信信号,可构建和模拟复杂的电磁环境,可广泛应用于个人移动通信、军事通信、卫星通信等领域。展开更多
Power line communication technology is used in various applications, from high voltage network to the low voltage network, as it is the only wired communication technology that is comparable with wireless communicatio...Power line communication technology is used in various applications, from high voltage network to the low voltage network, as it is the only wired communication technology that is comparable with wireless communication network. It works by injecting a modulated carrier wave into the electric cables from one transceiver to another. But still, the noise level and impedance mismatch are still the main concern of this technology, particularly in the low voltage network in residential area. Power line has additive non-white noise and extremely harsh environment for communication. At the same time, there is signal attenuation along the power line caused by the impedance mismatch in the power line network. Even though these problems can be controlled using a band-pass filter and an impedance matching circuit respectively, but the impedances in the power line are time and location variant and it is rather difficult to design a circuit that allows maximum power transfer in the system all the time. Thus in this paper, a new adaptive impedance matching circuits is proposed for narrowband power line communication. This methodology is derived based on the RLC band-pass filter circuit. This concept is designed to achieve simpler configuration and higher matching resolution.展开更多
Network coding is proved to have advantages in both wireline and wireless networks. Especially, appropriate network coding schemes are programmed for underlined networks. Considering the feature of strong node mobilit...Network coding is proved to have advantages in both wireline and wireless networks. Especially, appropriate network coding schemes are programmed for underlined networks. Considering the feature of strong node mobility in aviation communication networks, a hop-by-hop network coding algorithm based on ad hoc networks was proposed. Compared with COPE-like network coding algorithms, the proposed algorithm does not require overhearing from other nodes, which meets confidentiality requirements of aviation communication networks. Meanwhile, it does save resource consumption and promise less processing delay. To analyze the performance of the network coding algorithm in scalable networks with different traffic models, a typical network was built in a network simulator, through which receiving accuracy rate and receiving delay were both examined.The simulation results indicate that, by virtue of network coding, the proposed algorithm works well and improves performance significantly. More specifically, it has better performance in enhancing receiving accuracy rate and reducing receiving delay, as compared with any of the traditional networks without coding. It was applied to both symmetric and asymmetric traffic flows and, in particular, it achieves much better performance when the network scale becomes larger. Therefore, this algorithm has great potentials in large-scale multi-hop aviation communication networks.展开更多
文摘随着数字信号处理技术的发展,软件无线电平台显示出了其显著的特点和优越的性能,本文设计了一款通用的基于软件无线电平台的通信信号模拟器,可以实现复杂的通信信号电磁环境模拟。平台系统硬件设计主要包括现场可编程门阵列(field-programmable gate array,FPGA)、数模转换器(digital to analog convertor,DAC)芯片和时钟芯片,FPGA外挂大容量存储器DDR3设计等。平台系统软件设计包括信号调制部分和控制部分,其中信号调制部分能够实现多种通信信号的产生。控制部分主要用于解析主机软件对信号的配置和设置各类参数,并控制整个软件无线电平台协调工作。最后经实测验证,该平台能够灵活地模拟无线通信信号,可构建和模拟复杂的电磁环境,可广泛应用于个人移动通信、军事通信、卫星通信等领域。
文摘Power line communication technology is used in various applications, from high voltage network to the low voltage network, as it is the only wired communication technology that is comparable with wireless communication network. It works by injecting a modulated carrier wave into the electric cables from one transceiver to another. But still, the noise level and impedance mismatch are still the main concern of this technology, particularly in the low voltage network in residential area. Power line has additive non-white noise and extremely harsh environment for communication. At the same time, there is signal attenuation along the power line caused by the impedance mismatch in the power line network. Even though these problems can be controlled using a band-pass filter and an impedance matching circuit respectively, but the impedances in the power line are time and location variant and it is rather difficult to design a circuit that allows maximum power transfer in the system all the time. Thus in this paper, a new adaptive impedance matching circuits is proposed for narrowband power line communication. This methodology is derived based on the RLC band-pass filter circuit. This concept is designed to achieve simpler configuration and higher matching resolution.
基金Project(61175110)supported by the National Natural Science Foundation of ChinaProject(2012CB316305)supported by National Basic Research Program of ChinaProject(2011ZX02101-004)supported by National S&T Major Projects of China
文摘Network coding is proved to have advantages in both wireline and wireless networks. Especially, appropriate network coding schemes are programmed for underlined networks. Considering the feature of strong node mobility in aviation communication networks, a hop-by-hop network coding algorithm based on ad hoc networks was proposed. Compared with COPE-like network coding algorithms, the proposed algorithm does not require overhearing from other nodes, which meets confidentiality requirements of aviation communication networks. Meanwhile, it does save resource consumption and promise less processing delay. To analyze the performance of the network coding algorithm in scalable networks with different traffic models, a typical network was built in a network simulator, through which receiving accuracy rate and receiving delay were both examined.The simulation results indicate that, by virtue of network coding, the proposed algorithm works well and improves performance significantly. More specifically, it has better performance in enhancing receiving accuracy rate and reducing receiving delay, as compared with any of the traditional networks without coding. It was applied to both symmetric and asymmetric traffic flows and, in particular, it achieves much better performance when the network scale becomes larger. Therefore, this algorithm has great potentials in large-scale multi-hop aviation communication networks.
