A Concatenated ML Decoder for ST／SFBC-OFDM Systems in Double Selective Fading Channels

This paper presented a concatenated maximum-likelihood (ML) decoder for space-time/space-frequency block coded orthogonal frequency diversion multiplexing (ST/SFBC-OFDM) systems in double selective fading channels. The proposed decoder first detects space-time or space-frequency codeword elements separately. Then,according to the coarsely estimated codeword elements, the ML decoding is performed in a smaller constellation element set to searching final codeword. It is proved that the proposed decoder has optimal performances if and only if subchannels are constant during a codeword interval. The simulation results show that the performances of proposed decoder is close to that of the optimal ML decoder in severe Doppler and delay spread channels. However,the complexity of proposed decoder is much lower than that of the optimal ML decoder.     

Closed Loop Space-Time Block Coding for Wireless Downlink Transmission

In order to improve the poor performance of Space-Time Block Coding (STBC) in a downlink correlated fading environment, a closed loop scheme is proposed. With the known channel fading statistics fed from the receiver, eigenbeamforming is utilized to improve the performance of STBC at the transmitter. The new system achieves the array and diversity gain simultaneously. Because reduced dimension processing is adopted, the proposed system has a relative simple structure compared with the traditional beamforming system. The validity of the scheme is verified in several situations by simulation experiments.     

基于GPS的实时机车运行信息传输系统

利用铁路既有的列车无线调度通信系统和铁路分组交换网络，结合GPS技术，提出了一种实现机车运行信息实时传输的方案。采用话音压缩／扩展和数据同传，使无线列调在原来只传输话音的基础上增加了数据传送，数据仓库又使得这些信息能在铁路相关部门实现共享，可实现机车中低速率的数据传输。     

多径信道下基于最小平均峰度准则的盲多用户检测算法

基于最小平均峰度(LMK)准则，提出了一种适用于同步直扩码分多(DS／CDMA)系统多径慢衰落信道中的盲自适应多用户检测算法．这种算法基于高阶统计量特性，算法复杂度相对较低．仿真结果表明，该算法的稳态性能与子空间自适应多用户检测算法相当，是一种较好的多用户检测算法，有一定的实际应用价值．     

基于无线通信技术的单片机通信系统

通过对车载微机系统数据转储部分的改进，阐明了无线通信技术相对于传统通信技术的优越性；较详细地论述了无线通信领域的新型产品RF-418数传电台在车载微机系统中的具体应用，给出了接口电路设计和相关软件设计的具体实现方法；着重提高数据转储过程中通信的可靠性和实时性，使整个数据转储过程高效、便捷，更人性化、智能化。     

衡阳路源沥青材料

中兴智能交通系统（无锡）有限公司轨道交通专用车地无线通信系统ZITS—WCs20基于成熟的无线局域网802．11X系列技术标准构建，工作在2．4GHz／5．8GHz频段，主要功能是在城轨交通运行环境下，为车载应用设备和地面应用设备之间提供大容量、安全、连续、可靠的双向通信功能．实现列车与地面间数据、视频信息的实时透明传输。该系统基于分散控制，集中管理模式而开发，     

东信战略：立足国内参与全球——访东方通信股份有限公司技术副总监刘昆

东方通信是目前全球业界唯一一个提供同时支持TETBA，POT、模拟混合组网的集群通信系统解；臭方案的专业无线通信企业，将努力推进中国无线数字集群通信产业的发展、为全球的政府和公共安全、应急通信、交通物流、能源化工、公用事业、军事行动等提供具有国际领先艘术水平、安全可靠的专业无线通信系统，实现客户“随需而通、尽在掌握”的梦想。     

机车同步操控无线数据传输系统

介绍一种用于重载列车机车同步操控系统的适应于多山地区及隧道线路条件的无线数据传输系统。该系统能够保证同步操控数据的传输质量,提高同步操控系统的可靠性。