卫星非线性记忆信道中的最优信号设计与迭代接收技术

项目名称： 卫星非线性记忆信道中的最优信号设计与迭代接收技术

项目编号： No.61471037

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 王华

作者单位： 北京理工大学

项目金额： 83万元

中文摘要： 卫星数据业务的飞速增长，要求卫星通信采用大带宽、高频谱效率的传输技术提高通信速率。考虑到多载波应用和高阶调制信号的非恒包络特性，卫星转发器的非线性和记忆性再次成为制约系统总体传输性能的关键。本课题研究卫星非线性信道的最优信号设计与迭代接收技术。首先，分析非线性信道的容量，并通过组合优化方法搜索最佳信号星座和映射。然后，采用张量分解和空间交替广义期望最大(SAGE)算法对非线性信道进行参数估计和辨识。在此基础上，研究非线性信道最大后验概率(MAP)接收机的因子图表示，并采用置信压缩滤波(BCF)算法处理非线性因式节点的消息更新。针对信道记忆性较大的宽带应用环境，在接收端采用信道缩短滤波，并研究收发滤波器的联合优化。最后，对于非线性信道中的多用户频分复用，针对不同接收机研究采用时频压缩技术时的最优压缩参数和可达频谱效率。本课题的研究对非线性卫星信道的高效传输具有重要的理论意义和实际应用价值。

中文关键词： 卫星非线性信道；迭代接收；因子图；置信压缩滤波；时频压缩

英文摘要： Given the ever increasing demand for high data traffic rate, satellite communications are required to employ wideband and spectrum efficient transmission technologies to improve the transmission rate. Due to the nonconstant envelope of signals in multi-carrier applications and high order modulations, the nonlinear and memory phenomenons of satellite transponder become critical factors which determine the overall transimission performance of the system. In this proposal, we study the optimal signal design and iterative receiver in nonlinear satellite channels. First, the capacity of nonlinear channel will be analyzed and the optimal constellates and mapping can be obtained by combined searching. Then, the coefficents the nonlinear channel model are going to be estimated by tensor decomposition and space-alternating generalized expectation maximization (SAGE) algorithm. Building on this, the maximum-a-posteriori (MAP) reciever for nonlinear channel is represented by using factor graph (FG), and the belief condensation filter (BCF) will be applied as message passing to update the message from/to the factor node of nonlinear channel. For the wideband application with large channel memory, we propose to use a channel shortener as the front end filter, and joint optimize the transmit filter and channel shortening detector. Finally, in multi-user frequency division multiplex (FDM) satellite communication, time-frequency packing (TFP) technology is going to be studied. The optimal packing parameters and the achievable spectrum efficiency will be analyzed depending on the different receiver structures employed. The study of this proposal will contribute both the theoretic analysis and practical implementation of the efficient transmission in satellite nonlinear channels.

英文关键词： Nonlinear Satellite Channel;Iterative Receiver;Factor Graph;Belief Condensation Filter;Time Frequency Packing