CAREER: Coding for Wireless Communications

摘要：-通过无线信道传输语音和数据的需求正在以惊人的速度增长。不幸的是，无线信道的特性(例如，衰落和干扰)阻碍了满足这一需求。在衰落信道上实现可靠通信的最有效技术是“分集”，它试图为接收器提供独立衰落的传输信号副本。还可以使用信道编码来提供(一种形式的时间)分集，以针对无线信道的损伤进行免疫。此外，各种分集技术可以组合在一起，以进一步提高无线环境下的系统性能。空时编码结合了信道编码和空间分集技术，是近年来不同分集技术相结合的一个新的例子，已被证明是在衰落信道中提供高数据速率的有效方法。这项研究涉及为无线链路开发新的信道编码技术。具体地说，发展了块衰落信道上的公式发射和多接收天线系统的编码调制技术。研究的一个重要部分包括开发基于Turbo编码的调制技术，作为当前空时编码的替代方案。此外，研究人员还研究了在具有天线分集的系统中使用多级编码和比特交织编码调制方案。他们对各种编码调制系统进行了理论性能分析，制定了码设计原则，并设计出更简单高效的译码算法。此外，他们还考虑实际问题，包括在存在干扰的情况下对码性能的评估。

Abstract:---------The demand for voice and data transmission over wireless channels isincreasing at a tremendous pace. Unfortunately, the characteristics ofthe wireless channel (e.g., fading and interference) impose obstaclesfor satisfying this demand. The single most effective technique toaccomplish reliable communication over a fading channel is ``diversity''which attempts to provide the receiver with independently faded copiesof the transmitted signal. Channel coding may also be used to provide(a form of time) diversity for immunization against the impairmentsof the wireless channel. In addition, various diversity techniques maybe combined to further improve the system performance in a wirelessenvironment. Space-time coding which combines channel coding with spacediversity is a recent example of combining different diversity techniquesand has proven to be effective in providing high data rates over fadingchannels. This research involves development of new channel coding techniquesfor the wireless link. In particular, coded modulation techniques formultiple transmit and multiple receive antenna systems over blockfading channels are developed. A significant part of the research includesdevelopment of turbo (based) coded modulation techniques as an alternativeto the current space-time codes. In addition, the investigators study theuse of multilevel codes and bit interleaved coded modulation schemes forsystems with antenna diversity. They conduct a theoretical performanceanalysis of various coded modulation systems, develop code designprinciples, and devise simpler and efficient decoding algorithms. Inaddition, they consider practical issues including the evaluation of codeperformance in the presence of interference.