Channel Modeling and Design of Adaptive Space-Time Signal Processing System for High-speed Digital Mobile Communications

随着移动的通信的爆炸式增长，我们面临着频谱和容量不足的问题。此外，对包括图像和视频传输的多媒体通信的需求日益增长。因此，为了建立高速数字移动的通信系统，迫切需要建立一个精确的信道模型，并研制微波频段的信道特性测量系统。本研究从高速数字移动的通信的角度出发，构建了一个时域和空域信道特性测量系统。我们首先制作了一个离线测量系统，然后尝试制作一个基于DSP的在线测量系统。具体而言，我们成功地开发了一种多维估计方案，能够估计DOA，DOT和信号功率电平同时在有限的阵列天线和测量频率的条件下。本文利用神经网络和凸规划技术提出了一种新的协估计算法，并利用上述结果提出了几种自适应信号处理系统。主要成果包括采用多载波传输方案的阵列信号处理、分集技术与波束成形技术的关系、利用波达方向和点信息的新型预编码技术以及多维ESPRIT，组合阵列信号处理是提高传输质量（即快速跟踪和分组通过率）的一种很有前途的技术。

With an explosive growth of mobile communications, we are facing with a problem of shortage of frequency spectrum and capacity. Moreover there is a growing need for multi-media communications including picture and video transmission. It is therefore strongly desired to construct an accurate channel modeling in order to establish the high-speed digital mobile communication systems, and also to make a measuring system for channel characteristics at microwave frequency band.In this study, we constructed the measurement systems for channel characteristics in both space and time domain from the view point of high-speed digital mobile communications. At first we made an off-Line measurement system, and then tried to make an on-line system based on DSP's. Specifically, we succeeded to develop a multi-dimensional estimation scheme capable to estimate DOA, DOT and Signal Power level simultaneously under the condition of limited number of array antennas and measuring frequency. We developed a novel type co estimation algorithm by means of neural network and convex programming technique.Furthermore we proposed several types of adaptive signal processing systems by using the above mentioned results. Main achievements are the array signal processing by using a multi-carrier transmission scheme, the relationship of diversity technique and beam forming technique, the novel precoding techniques utilizing DOA and DOT information and the multi-dimensional ESPRIT.Combined array signal processing are a promising technique for the improvement of transmission quality i.e. fast tracking and packet through rate.