CAREER: Channel Coding for Satellite and Mobile Communications

通过卫星和无线通信网络的话音和数据通信业务的迅速增长，已导致将最新的数字通信技术迅速纳入当前的系统。这些网络的下一代将需要在系统的每个点上使用更复杂的技术。很明显，为了对抗信道传输效应，更有效地利用系统资源和促进多用户访问，信道编码将无处不在。这个项目关注的是调查新的信道编码类别来满足这些需求。特别是，正在开发新的时变编码，以减少发射机功率要求，并使系统能够在接近理论极限的情况下运行，并具有几个等级的服务质量。此外，新的迭代解码算法和软信息交换范例正在开发中，为各种系统功能（如定时和同步以及多用户检测）提供强大的集成解决方案。该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需求的背景下设计，分析和时变信道码的性能。所研究的码类包括块码和格码的并行和串行连接，以及周期性时变卷积码的新类别。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。正在作出特别的努力来开发代码，包括不对称并行连接，具有短块长度和在各种错误率下接近容量的性能，用于移动无线通信。迭代解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颖的联合源/信道编码结构相互作用的低信噪比定时和同步算法。也正在研究信道码的迭代解码，作为开发迭代多用户检测算法的一种手段，在高负载的多用户系统上实现接近单用户的容量。

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.