OFDM传输体制的MIMO雷达自通信系统研究

Wireless communication among the shipboard radars or aiborne radars is requisite for data fusion. Similarity on the system diagram between the radar system and communication system makes it possible to design the self communication system on the basis of the radar system. This is significant for the netted radar application. The waveform diversity enables the MIMO radar superiority in several functional domain. Firstly, the parameter identifiability is improved. Secondly, it achieves the similar goal as the adaptive arrays for target detection and parameter estimation. Thirdly, the transmitting beampattern design is flexible for MIMO radar. On the other hand, OFDM-coded radar signals are comparable with linear frequency modulation (LFM) signals and furthermore, experiences no range-Doppler coupling. It should be possible, with appropriate waveform design and signal processing, to achieve both radar and communications capability using a single OFDM waveform in MIMO radar system. Per transmiting antenna power control and the antenna selection help the MIMO radar to improve the capability and limit the communication capability. Under this condition, the MIMO channel capacity is studied with the correlation between the transmiting antennas, the correlation between the receiving antennas and the multipath correlation. OFDM signal has the large power-to-average power ratio, is sensitive to the frequency offset between the transmitter and receiver, and has the large power spectrum sidelobes. The preprosessing techniques is studied to suppress these disadvantages of OFDM-coded radar signal. For the Ad hoc network consists of several OFDM-based MIMO radar self-communication systems, the all-to-all information sharing is studied based on the cross-layer design. These researches cover the system design, waveform design and networking for the radar self-communication.

机载或舰载雷达之间的无线通信是实现雷达数据融合的必要条件。由于雷达系统和通信系统在系统结构上的相似性，借助雷达系统的硬件平台实现雷达之间直接的无线通信，对于雷达组网应用有重要的理论价值和实践意义。共址相干MIMO雷达具备较强的目标辨识能力和灵活的发射波束成形能力，采用OFDM波形后能在时间维和频率维获得自由度。在考虑MIMO雷达的每天线发射功率控制、天线选择的基础上，综合发射天线相关性、接收天线相关性和多径相关性，分析基于OFDM的MIMO雷达自通信系统的信道容量。针对OFDM信号峰均功率比过高、对频偏敏感、功率谱旁瓣过大等不利因素，研究采用发射端预处理的方法进行抑制，优化设计OFDM雷达波形。对于多个基于OFDM的MIMO雷达自通信系统组成的Ad hoc网络，研究跨层协议设计方法实现全网信息共享。通过对雷达自通信系统、波形、组网领域的理论研究为进一步拓展雷达功能奠定基础。

本项目面向机载和舰载雷达组网应用，致力于解决在MIMO雷达基础上实现雷达自通信的可行性、可用性和实现方法等基础性问题。. 根据共址MIMO雷达和统计MIMO雷达的特点设计MIMO雷达自通信方法，使用信息论方法将雷达波形设计和通信信号设计联系起来，用矩阵论方法为雷达回波信号和自通信信号的传播信道分别建模，使用注水功率分配方法设计了最优MIMO雷达自通信波形，研究了未知雷达回波响应统计特征和已知雷达回波响应统计特征条件下的通信信号设计，仿真研究了最优设计条件下雷达互信息和自通信信道容量，比较了雷达性能最优条件下通信信道容量损失和通信性能最优条件下雷达互信息损失。. 针对MIMO-OFDM雷达自通信系统网内节点少、雷达和通信性能对多用户信号正交性要求高等特点，提出了基于预编码的阵分多址波形设计。预编码在OFDM信号调制之前，可以在不改变现有基带信号处理架构的条件下实现，而且通过在接收端采用高级信号处理算法获得较高的通信性能。提出了若干种预编码方案，并且仿真比较了不同预编码的性能。. 针对MIMO雷达自通信系统定向传输的特点，研究方向性天线下带有雷达信息辅助的邻居发现方法，采用排队论和概率论方法确定扫描截止时间，提出两种邻居发现停止准则；研究了面向全网信息共享的时隙与波束调度方法，采用图论方法为网内链路冲突建模并制定调度规则，设计了高可靠和高效率的信息共享协议；开发了雷达通信一体化组网半实物仿真平台，为组网应用算法验证提供支持。. 基于上述创新成果，项目组发表期刊论文7篇，其中国际期刊3篇，国内期刊4篇；会议论文9篇，其中国际会议7篇，国内会议2篇，均被或即将被SCI或EI检索。获得发明专利授权2项；培养已毕业研究生2名；开发了一套仿真平台，为后续研究和成果深化打下了坚实的基础。研究成果各项指标达到立项时的预期目标。