ITR Collaborative Research: Achieving the Rate-Diversity Tradeoff in Space-Time Codes

在无线通信环境中，接收到的信号强度会出现不可预测的、经常是快速的波动。在蜂窝通信中掉线通常是由于衰落造成的。一种非常有效和最新的对抗衰落的技术是在输入端（发射端）和输出端（接收端）同时使用多个天线。空时通信信道用于描述存在多个输入和输出天线的衰落无线通信信道。多输入和多输出可以用来增加无线通信信道的可靠性，或者通过一个可能等于发射天线数量的因素来增加信息传输的速率。当既要提高可靠性又要提高信息传输速率时，在提高信息传输速率和相应的通信链路可靠性之间需要进行权衡。这种权衡被称为速率分集权衡。本项目的主要目标是设计信号集，允许用户在速率分集权衡曲线上选择一个工作点。其他目标包括帮助定义和实现时空通信信道的极限。更具体的目标包括设计实现速率分集折衷且易于解码的信号集，研究信道容量的替代相关概念，如延迟限制信道容量，研究其他相关信道模型，包括那些包含信道存储器和相关路径增益的信道模型，研究存在反馈的时空信道以及存在具有多分辨率能力的源。

ABSTRACT0325180Xiang-gen XiaUniversity of DelawareThe term fading is used to describe the unpredictable and often rapid fluctuation in received signal strength encountered in a wireless communication environment. Dropped calls in cellular communication are often attributable to fading. A very effective and recent technique used to combat fading is to use multiple antennas at both input (transmitter end) and output (receiver end). The term space-time communication channel is used to describe the fading, wireless communication channel in the presence of multiple input and output antennas. Multiple input and output can be used to either increase the reliability of a wireless communication channel or else increase the rate at which information can be transmitted by a factor potentially equal to the number of transmit antennas. When used to both increase reliability and rate of information transfer, there is a tradeoff between the increase in information rate and the corresponding reliability of the communication link. This tradeoff is referred to as the rate-diversity tradeoff. A principal goal in the present project is the design of signal sets that will allow the user to pick an operating point along the rate diversity tradeoff curve. Other goals include helping define and achieve the limits of the space-time communication channel.More specific objectives include the design of signal sets that achieve the rate-diversity tradeoff and that are easy to decode, the study of alternative relevant notions of channel capacity such as delay-limited channel capacity, the study of other relevant channel models including those incorporating channel memory and correlated path gains, the study of the space-time channel in the presence of feedback as well as in the presence of sources having a multi-resolution capability.