CAREER: Coding for Wireless Communications

摘要：---------对无线信道的语音和数据传输的需求正以惊人的速度增长。不幸的是，无线信道的特性（例如，衰落和干扰）对满足这一需求造成了障碍。在衰落信道上实现可靠通信的唯一最有效的技术是“分集”，它试图向接收机提供传输信号的独立衰落副本。信道编码还可用于提供（一种时间形式）分集，以免疫无线信道的损伤。此外，可以将各种分集技术相结合，进一步提高系统在无线环境中的性能。将信道编码与空间分集相结合的空时编码是最近结合不同分集技术的一个例子，并已被证明在衰落信道上提供高数据速率是有效的。本研究涉及无线链路新信道编码技术的开发。特别地，开发了分组衰落信道上的多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的编码调制技术，作为当前空时编码的替代方案。此外，研究人员还研究了多电平编码和位交错编码调制方案在天线分集系统中的应用。他们对各种编码调制系统进行理论性能分析，开发代码设计原则，并设计更简单有效的解码算法。此外，他们还考虑了实际问题，包括在存在干扰的情况下对代码性能的评估。

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.