衰落信道下合作编码的研究.pdf

摘要
摘 要
在无线通信中，当移动台由于尺寸或其他的约束条件不能支持多元天线时，
常规的空时编码就不能被用于提供上行链路的传输分集。为了解决此问题，提出
了多用户合作分集的概念，移动台通过中继传输彼此的信息获得传输分集。
本文采用理论分析和计算机仿真相结合的方法，详细研究了合作编码分集技
术的原理及性能，主要完成工作有以下几个方面：
，以及在此基础上提出的用户合作分集技术
的系统模型，并对此模型进行了理论分析。
。代替以往简单的重复中继传
输，合作编码区分通过独立衰落信道的每个移动台的编码和每段编码的传输部分。
。首先，我们借助空时编码的思想在快衰落情况
下增加合作编码的分集。我们计算比特和码组差错率的界限值来证明它的增益。
其次，由于合作编码包含两个编码部分，所以很自然的在这个框架里应用了 Turbo
编码。我们研究 Turbo 编码在合作编码中的应用及通过错误界限和仿真来证明它的
误码性能增益。

关键词：分集技术 用户合作 合作编码 空时合作编码 Turbo合作编码
ABSTRACT
ABSTRACT
When mobiles cannot support multiple antennas due to size or other constraints in
wireless communications, conventional space-time coding cannot be used to provide
uplink transmit diversity. To address this limitation, the concept of coded cooperation
has been introduced, where mobiles achieve transmit diversity by relaying each other’s
messages.
This thesis studies the basic principle of coded cooperation diversity with
theoretical analysis and simulation. The main results and contents are as follows.
1. The principles of diversity are introduced. Based on these, the system model of
user cooperation is discussed with theoretical analysis.
2. The principle and system of coded-cooperation is discussed. Instead of a
simple repetition relay, coded cooperation partitions the code words of each mobile and
transmits portions of each codeword through independent fading channels.
3. Two extensions to the coded cooperation framework are presented. First, the
diversity of coded cooperation is increased in the fast-fading scenario via ideas
borrowed from space-time codes, and bounds for the bit-and block-error rates are
calculated to demonstrate the resulting gains. Second, since cooperative coding contains
two code components, it is natural to apply turbo code