动态稀疏双扩展信道下的多用户通信研究

Underwater mobile communication networks have receive a wide range of concerns since the developing requirements of underwater intelligence surveillance systems for our country. The main obstacles can be devided into two parts. The first part is the dynamic time-delay and Doppler doubly spread channels which are caused by platforms maneuverations, surface waves and internal waves. The second part is the cross-channel interferences cancellation problems which are caused by the doubly spread multiple access channels. This project is about the development of an efficient and reliable communication system over underwater mobile multiple access channels. First, because of the dynamic and sparse features of oceanic time delay and Doppler doubly spread channels, we will analyse the lake and sea experiment data to derive the channels dynamic and their sparse characterization. The compressive sequential estimation algorithm , which is able to track the dynamic sparse doubly spread channels, will be studied. The cooperative processing between the doubly channel estimation and Turbo equalizer will be studied. The doubly spread channels estimation will be introduced into the soft information iteration of Turbo equalizer to improve the channel estimation and communication system performances. On this basis, the spatial-temporal-frequency general sidelobe canceller which is based on the doubly spread channel estimation will be studied in order to suppress the cross channel interferences from the multiple access channels and realize spatial and frequency diversity over dynamic doubly spread channels. The project is useful for providing early theoretical study and real-time key signal processing algorithm to the construction of fast and reliable underwater mobile communication networks.

水下移动通信网随我国水下情报监测系统的需求而受到广泛关注，其中核心的难点问题是由水下移动通信平台快速机动及浅海表面波、内波等所共同导致的信道动态时延—多普勒双扩展特性及双扩展信道下多用户同道间干扰抵消问题。本项目拟研究水下移动多接入信道下的高效、可靠通信系统：针对海洋时延多普勒双扩展信道的动态性和稀疏性特征，采用湖、海试数据分析信道的动态演化特性和稀疏表征方法，研究能动态跟踪稀疏双扩展信道的压缩序贯估计算法；研究双扩展信道估计器与Turbo均衡器的协同处理，将双扩展信道估计引入均衡器的软信息迭代中来协同提高信道估计和通信系统的性能；在此基础上，研究基于动态双扩展信道估计的空—时—频广义旁瓣抵消器结构，以抑制多接入信道的同道间干扰和实现动态双扩展信道下的时频两维分集。本项目的研究可为构建通信速率高、误比特率低，即物理层可靠的水下移动通信网提供前期理论研究支持和实时核心信号处理算法。

水下移动通信网随我国水下监测系统的需求而受到广泛关注，其中核心的难点问题是由水下移动通信平台快速机动及浅海表面波、内波等所共同导致的信道动态时延—多普勒双扩展特性及双扩展信道下多用户同道间干扰抵消问题。本项目针对海洋时延多普勒双扩展信道的动态性和稀疏性特征，分析了信道的动态演化特性和稀疏表征方法，研究能动态跟踪稀疏双扩展信道的压缩序贯重构算法；研究双扩展信道估计器与Turbo均衡器的协同处理，将双扩展信道估计引入均衡器的软信息迭代中来协同提高信道估计和通信系统的性能；研究基于动态双扩展信道估计的空—时—频广义旁瓣抵消器结构，并基于矩阵块Toeplitz特性开发快速算法,抑制多接入信道的同道间干扰和实现动态双扩展信道下的时频两维分集。项目按计划开展了研究, 形成了动态信道对信号幅度、信号相位的去相关分析及概率信道模型。通过仿真及实际试验数据对凸集投影算法及其收敛性进行了研究，并对其进行了仿真分析及湖、海试试验验证，验证过程中，算法对中等信噪比条件数据可收敛，由于算法对信号信噪比存在一个收敛的阈值，故算法对部分高星座图通信情况失效。形成了SISO双扩展信道估计器及双扩展信道下的Turbo通信系统,对湖\海数据进行了分析,试验数据中表明了采用分段阵处理结合本项目的空-时-频广义旁瓣抵消器可有效抵消同道间干扰及动态信道的影响。本项目的研究为构建通信速率高、误比特率低，即物理层可靠的水下移动通信算法进行了前期理论探索研究,可为后续工程化应用打下基础。