基于3Gpp长期演进(long term evolution,LTE)下行无线帧结构和相关物理层信号标准,研制了便携式TDD-LTE矢量信号发生器。详细介绍了信号发生器的硬件设计与软件架构。该设备采用了数据预存储方案,用专门设计的软件程序生成不同配置的TDD...基于3Gpp长期演进(long term evolution,LTE)下行无线帧结构和相关物理层信号标准,研制了便携式TDD-LTE矢量信号发生器。详细介绍了信号发生器的硬件设计与软件架构。该设备采用了数据预存储方案,用专门设计的软件程序生成不同配置的TDD-LTE下行无线帧数据,并存储到FLASH存储器中,然后把某一帧数据用模数转化器生成模拟信号,最后通过射频模块把生成的模拟信号发射出去。用安捷伦89600矢量信号分析软件结合矢量分析仪对研制的矢量信号发生器进行了测试,测试结果表明该矢量信号发生器产生的无线信号可以被正确解调,且其误差矢量幅度小于3%,完全符合TDD-LTE协议规范。该设备可为TDD-LTE建网前的小区规划测试提供模拟的TDD-LTE基站下行无线信号。展开更多
To reduce vehicle emissions in road networks, a new signal coordination algorithm based on approximate dynamic programming （ADP） is developed for two intersections. Taking the Jetta car as an experimental vehicle, f...To reduce vehicle emissions in road networks, a new signal coordination algorithm based on approximate dynamic programming （ADP） is developed for two intersections. Taking the Jetta car as an experimental vehicle, field tests are conducted in Changchun Street of Changchun city and vehicle emission factors in complete stop and uniform speed states are collected. Queue lengths and signal light colors of approach lanes are selected as state variables, and green switch plans are selected as decision variables of the system. Then the calculation model of the optimization index during the planning horizon is developed based on the basis function method of the ADP. The temporal-difference algorithm is employed to update the weighting factor vector of the approximate function. Simulations are conducted in Matlab and the results show that the established algorithm outperforms the conventional coordination algorithm in reducing vehicle emissions by 8.2%. Sensitive analysis of the planning horizon length on the evaluation index is also conducted and the statistical results show that the optimal length of the planning horizon is directly proportional to the traffic load.展开更多
文摘基于3Gpp长期演进(long term evolution,LTE)下行无线帧结构和相关物理层信号标准,研制了便携式TDD-LTE矢量信号发生器。详细介绍了信号发生器的硬件设计与软件架构。该设备采用了数据预存储方案,用专门设计的软件程序生成不同配置的TDD-LTE下行无线帧数据,并存储到FLASH存储器中,然后把某一帧数据用模数转化器生成模拟信号,最后通过射频模块把生成的模拟信号发射出去。用安捷伦89600矢量信号分析软件结合矢量分析仪对研制的矢量信号发生器进行了测试,测试结果表明该矢量信号发生器产生的无线信号可以被正确解调,且其误差矢量幅度小于3%,完全符合TDD-LTE协议规范。该设备可为TDD-LTE建网前的小区规划测试提供模拟的TDD-LTE基站下行无线信号。
基金The National High Technology Research and Development Program of China (863 Program ) (No. 2011AA110304 )the National Natural Science Foundation of China (No. 50908100)
文摘To reduce vehicle emissions in road networks, a new signal coordination algorithm based on approximate dynamic programming （ADP） is developed for two intersections. Taking the Jetta car as an experimental vehicle, field tests are conducted in Changchun Street of Changchun city and vehicle emission factors in complete stop and uniform speed states are collected. Queue lengths and signal light colors of approach lanes are selected as state variables, and green switch plans are selected as decision variables of the system. Then the calculation model of the optimization index during the planning horizon is developed based on the basis function method of the ADP. The temporal-difference algorithm is employed to update the weighting factor vector of the approximate function. Simulations are conducted in Matlab and the results show that the established algorithm outperforms the conventional coordination algorithm in reducing vehicle emissions by 8.2%. Sensitive analysis of the planning horizon length on the evaluation index is also conducted and the statistical results show that the optimal length of the planning horizon is directly proportional to the traffic load.
