高铁无线通信可靠传输波形研究与性能分析

针对高速铁路应用中高动态环境大容量信息可靠传输能力提升的需求,通过分析无线通信系统因高速移动而面临的多径衰落、多普勒效应以及信道时变性等传输环境因素,分别基于正交频分复用(OFDM)和正交时频空(OTFS)设计高速铁路应用场景下的无线通信传输波形,并通过搭建模拟高速移动传输环境开展对2种传输波形在多参数可变条件下传输误码率的性能仿真实验。仿真结果证明,在120 km/h、360 km/h和500 km/h的场景下达到相同传输误码率时,所设计的OTFS传输波形比OFDM传输波形对信噪比需求分别降低了6 dB、8 dB和12 dB,表明基于OTFS的传输波形在多径时延拓展和多普勒偏移较大的情况下仍能够较好抑制快时变信道带来的衰落,实现了更可靠的数据传输。

基于多参数识别的电力载波通信信号监测系统设计

电力载波通信信号在传输过程中存在衰减,为降低电力载波通信传输误码率,实时监测信号传输行为,设计了基于多参数识别的电力载波通信信号监测系统。根据动态遗忘因子取值范围,建立多参数识别机制,再联合相关载波通信数据,求解信号衰减参数,完成对电力载波通信的可行性分析。按照载波通信体系整体架构的布局形式,确定滤波器、耦合器元件所属连接位置,完成电力载波通信信号监测系统设计。对比实验结果表明,在多参数识别机制作用下,电力载波通信传输误码率最大值仅为23.5%,在实时监测信号传输行为方面具有突出应用价值。

海面无线局域传感网络的数据通信协议研究

无线传感网络的应用已经逐渐由陆地发展到海洋。海洋观测数据与水下声学感知信息实时、高效、精准上传至岸基或母船,离不开无线传感网络中的数据传输系统与通信协议的协调搭配。通过软件仿真分析无线电台传输频率与系统数据通信协议传输误码率间的关系,搭建无线数据传输系统,实现数据收发功能,完成了外场湖面单节点无线电台拉锯通信。根据测试结果进行了多节点无线电台收发数据拥塞、信号串扰以及数据价值等相关领域研究。最后对海面无线数据传输系统进行功能分析,基于系统完备性的数据通信协议满足无线数据传输系统通信距离大于6 km的性能指标需求,为进一步实现海洋无线局域多传感器网络融合、打造智慧海洋提供有力支撑。

基于最小二乘支持向量机的无线网络信道检测

为了获得理想的无线网络信息检测结果,提出了基于最小二乘支持向量机的无线网络信道机制.首先对当前无线网络信道检测的研究现状进行分析,并建立无线网络信道检测的假设模型,然后采用最小二乘支持向量机构建无线网络信道检测模型,并通过粒子群算法对最小二乘支持向量机参数进行优化,最后在Matlab 2014平台上进行了无线网络信道检测的仿真实验,以验证无线网络信道检测的有效性.结果表明,最小二乘支持向量机获得了高精度的无线网络信道检测结果,无线网络的数据传输成功率得以改善,大幅度降低了数据传输的误码率,在相同实验条件下,无线网络信道检测结果明显高于当前经典检测机制,验证本文机制的优越性.

激光视频通信系统的设计与实现

视频通信系统的研究具有重要的意义,针对当前视频通信系统存在的通信质量差、稳定性差等缺陷,提出一种基于激光技术的视频通信系统。首先对当前视频通信系统的研究现状进行研究,找到视频通信系统的通信量大、信号时变性等特点,然后采用激光传感器作为通信系统的信号采集设备,并通过激光技术实现视频系统的信号传输,最后对设计的激光通信系统的性能进行测试。结果表明,该系统可以大幅度加快视频通信的速度,克服当前视频通信通信系统存在的局限性,降低了视频信号传输的误码率,具有较高的实际应用价值。

Performance Analysis of Optical Transmission Based on Seven Cores Fiber

This essay designed a kind of new seven-core fiber with lower crosstalk and loss, and made space division multiplexing transmission experiment based on this seven-core fiber. It is known that crosstalk has the most serious influence in multicore fiber transmission process. Before the experiment, the affecting factors of fiber crosstalk were analyzed through simulation, such as core space, bending radius, and fiber length. Combined with the simulation analysis, the design scheme of multicore fiber with low crosstalk was obtained. Before the fiber design, various factors of influence crosstalk such as the core- to-core distance, bending radius, fiber length and so on. Based on the simulation analysis, conclusion has made on the design scheme of multi-core optimal fiber with low crosstalk. The space division multiplexing and wavelength division multiplexing technology, was adopted to conduct seven-core optical fiber transmission of 58.7kin.The crosstalk of adjacent core was suppressed to as low as 45dB / km, the attenuation of inner core was 0.24dB/ km, the outer cores＇ 0.32dB/km. Different bit error rate （BER） performances were also studied under different conditions, through reasonably designing the system to reduce the error rate, improve the performance of the system, and realize long distance and large capacity transmission with fiber.

RedBridgeⅢ高清板卡

大洋公司推出的首款高清板卡-RedBridgeⅢ。提供了高清解决方案的新选择。

Hybrid coordinated strategy of downlink coordinated multi-point transmission

Coordinated multi-point （CoMP） transmission is put forward in the long term evolution-advanced （LTE-A） system to improve both average and cell-edge throughput. CoMP-joint pro- cessing （JP） scheme can get a larger cell-edge throughput and a lower bit error rate （BER） than the CoMP-coordinated beamform- ing （CB） scheme, but it also has higher complexity due to data sharing. A hybrid coordinated strategy with parameter c~, which indicates the proportion of users employing the CoMP-JP scheme, is proposed to apply the CoMP-JP scheme to improve the poorer communication quality of cell edge and employ the CoMP-CB scheme for other users to enhance average throughput and spec- tral efficiency. This paradigm selects users defined by the certain threshold of signal to interference plus noise power ratio （SINR） corresponding to the parameter a to the CoMP-JP scheme. This paper compares the BER performance between the block diag- onalization （BD） based precoding and the linear precoders by maximizing signal to leakage and noise ratio （SLNR）, and also in- dicates that the SLNR based precoding algorithm gets lower BER than the BD based precoding algorithm with certain signal-to-noise ratios （SNRs）. Finally, this paper discusses that the system perfor- mance is partially affected by the percentage of CoMP-JP users and concludes that 50% of users sorted to communicate under the CoMP-JP scheme will reach the best system performance.

Performance analysis of quantum key distribution based on air-water channel

Considering the air-water interface and ocean water’s optical attenuation,the performance of quantum key distribution(QKD)based on air-water channel is studied.The effects of photons’various incident angles to air-water interface on quantum bit error rate(QBER)and the maximum secure transmission distance are analyzed.Taking the optical attenuation of ocean water into account,the performance bounds of QKD in different types of ocean water are discussed.The simulation results show that the maximum secure transmission distance of QKD gradually reduces as the incident angle from air to ocean water increases.In the clearest ocean water with the lowest attenuation,the maximum secure transmission distance of photons far exceeds the the working depth of underwater vehicles.In intermediate and murky ocean waters with higher attenuation,the secure transmission distance shortens,but the underwater vehicle can deploy other accessorial methods for QKD with perfect security.So the implementation of OKD between the satellite and the underwater vehicle is feasible.