CAREER: Channel Coding for Satellite and Mobile Communications

卫星和无线通信网络上的语音和数据通信服务的快速增长导致将最先进的数字通信技术迅速纳入当前的系统。下一代这些网络将在系统的每一个点上要求更复杂的技术。显然，为了对抗信道传输影响、更有效地利用系统资源和促进多用户接入，信道编码将无处不在。该项目致力于研究新的信道码类别以满足这些需求。特别是，正在开发新类别的时变码，以降低发射机功率需求，并使系统能够在接近理论极限的情况下以几种服务质量级别运行。此外，新的迭代译码算法和软信息交换范例正在被开发，以便为诸如定时和同步以及多用户检测等各种系统功能提供健壮的综合解决方案。本项目涉及在信息论基本定理和下一代卫星和无线通信系统的需求的背景下的时变信道码的设计、分析和性能。正在研究的码类包括分组和网格码的并行和串行级联，以及新的周期性时变卷积码。研究了这些编码方案在加性高斯白噪声信道和各种多径衰落信道模型下的性能。正在做出特别的努力来开发用于移动无线通信的码，包括非对称并行级联，其具有较短的块长度和在各种误码率下的接近容量性能。迭代译码和软信息交换的原理也被用来增强系统的其他功能。这包括与软输出信道解码算法和新型联合信源/信道编码结构交互的低信噪比、定时和同步算法。信道编码的迭代译码也被研究为开发迭代多用户检测算法的手段，所述迭代多用户检测算法在高负载多用户系统上实现近乎单用户容量。

The rapid growth in voice and data communications services over satellite and wireless communication networks has resulted in the rapid incorporation of the state of the art in digital communication techniques into current systems. The next generation of these networks will demand even more sophisticated techniques at every point in the system. It is evident that channel coding will be ubiquitous in order to combat channel transmission effects, to more efficiently utilize system resources and to facilitate multiuser access. This project is concerned with the investigation of new classes of channel codes to meet these demands. In particular, new classes of time varying codes are being developed to reduce transmitter power requirements and to enable systems to operate close to theoretical limits with several levels of quality of service. In addition, new iterative decoding algorithms and soft information exchange paradigms are being developed to provide robust integrated solutions to a variety of system functions such as timing and synchronization and multiuser detection.This project involves the design, analysis and performance of time-varying channel codes in the context of the basic theorems of information theory and the demands of the next generation of satellite and wireless communication systems. The classes of codes being studied include parallel and serial concatenation of block and trellis codes and new classes of periodically time varying convolutional codes. The performance of these coding schemes is studied for both the additive white Gaussian noise channel and a variety of multipath fading channel models. A particular effort is being made to develop codes, including asymmetric parallel concatenations, with short block lengths and near capacity performance at a variety of error rate for mobile wireless communications. The principle of iterative decoding and soft information exchange is also being exploited to enhance other system functions. This includes low signal to noise ratio timing and synchronization algorithms that interact with soft output channel decoding algorithms and novel joint source/channel coding structures. Iterative decoding of channel codes is also being investigated as a means of developing iterative multiuser detection algorithms that achieve near single user capacity on highly loaded multiuser systems.