UAV data link has been considered as an important part of UAV communication system, through which the UAV could communicate with warships. However, constant coding and modulation scheme that UAV adopts does not make f...UAV data link has been considered as an important part of UAV communication system, through which the UAV could communicate with warships. However, constant coding and modulation scheme that UAV adopts does not make full use of the channel capacity when UAV communicates with warships in a good channel environment. In order to improve channel capacity and spectral efficiency, adaptive coded modulation technology is studied. Based on maritime channel model, SNR estimation technology and adaptive threshold determination technology, the simulation of UAV data link communication is carried out in this paper. Theoretic analysis and simulation results show that according to changes in maritime channel state, UAV can dynamically adjust the adaptive coded modulation scheme on the condition of meeting target Bit-Error-Rate (BER), the maximum amount of data transfer is non-adaptive systems three times.展开更多
数据质量控制是智能交通系统应用建设的关键技术之一。基于对无线射频识别(Radio Frequency Identification,RFID)数据特性的分析,将RFID错误数据分为4类,并针对每一种错误类型的特点设计合理的识别算法,从而给出一套完整的错误数据检...数据质量控制是智能交通系统应用建设的关键技术之一。基于对无线射频识别(Radio Frequency Identification,RFID)数据特性的分析,将RFID错误数据分为4类,并针对每一种错误类型的特点设计合理的识别算法,从而给出一套完整的错误数据检测方法及流程。提出了从基站、时间和错误类型等3个角度对RFID数据的错误率进行分析的方法,并选取南京市区主干道上21个RFID基站的原始数据作为实例,对所提出方法进行了验证。结果表明,21个基站采集的数据的平均错误率为0.044 3%,最小值为0.021 4%,最大值为0.080 7%,说明RFID数据采集技术所采集到的数据具有较高的可靠性,且数据错误率与车流量具有明显的正相关性。同时,各个基站采集的数据中车牌号字符串长度异常占所有错误类型比例的平均值为72.93%,最小值为42.24%,最大值为98.75%,表明电子标签写入信息出错是造成错误数据的主要原因。针对分析结果,给出了相应的质量控制措施以控制RFID错误数据的产生。展开更多
联合战术信息分发系统(Joint Tactical Information Distribution System,简称JTIDS)采用组合调制体制以及多层编码体系保证报文传输的可靠性,本文提出了JTIDS数据链报文传输可靠性的评价模型,分析了该系统在莱斯衰落信道环境和部分频...联合战术信息分发系统(Joint Tactical Information Distribution System,简称JTIDS)采用组合调制体制以及多层编码体系保证报文传输的可靠性,本文提出了JTIDS数据链报文传输可靠性的评价模型,分析了该系统在莱斯衰落信道环境和部分频带干扰条件下的符号误码率和报文丢失率,并利用SIMULINK仿真平台对JTIDS数据链报文传输过程进行设计、建模和仿真,并对结果进行分析。仿真结果显示,由于JTIDS系统将RS编码、交织等多种编码技术和DS/FFH MSK调制技术相结合,使其在复杂信道环境下保持较低的符号误码率及报文丢失率,满足数据链报文传输可靠性的要求。展开更多
文摘UAV data link has been considered as an important part of UAV communication system, through which the UAV could communicate with warships. However, constant coding and modulation scheme that UAV adopts does not make full use of the channel capacity when UAV communicates with warships in a good channel environment. In order to improve channel capacity and spectral efficiency, adaptive coded modulation technology is studied. Based on maritime channel model, SNR estimation technology and adaptive threshold determination technology, the simulation of UAV data link communication is carried out in this paper. Theoretic analysis and simulation results show that according to changes in maritime channel state, UAV can dynamically adjust the adaptive coded modulation scheme on the condition of meeting target Bit-Error-Rate (BER), the maximum amount of data transfer is non-adaptive systems three times.
文摘联合战术信息分发系统(Joint Tactical Information Distribution System,简称JTIDS)采用组合调制体制以及多层编码体系保证报文传输的可靠性,本文提出了JTIDS数据链报文传输可靠性的评价模型,分析了该系统在莱斯衰落信道环境和部分频带干扰条件下的符号误码率和报文丢失率,并利用SIMULINK仿真平台对JTIDS数据链报文传输过程进行设计、建模和仿真,并对结果进行分析。仿真结果显示,由于JTIDS系统将RS编码、交织等多种编码技术和DS/FFH MSK调制技术相结合,使其在复杂信道环境下保持较低的符号误码率及报文丢失率,满足数据链报文传输可靠性的要求。
