【作者】 何亮；

【导师】 仇佩亮；

【作者基本信息】 浙江大学 ， 信息与通信工程， 2006， 硕士

【摘要】 合作通信使单天线用户通过与网络中其余用户的合作,在不增加额外发送功率和扩展通信带宽的前提下,有效抵抗无线信道的选择性衰落,获取空间分集增益,这种空间分集也被称作合作分集。常见的合作通信协议有放大前向协议、译码前向协议和码的合作协议。本文详细分析采用这三种协议的无线合作通信网络的性能,求出中断概率在高信噪比域的近似表达式,计算合作分集指数,理论预测与仿真结果吻合。理论预测和仿真结果证明:从中断概率角度考虑,这三类合作通信协议均能达到完全的合作分集增益。基于中断概率在高信噪比域的近似表达式,讨论放大前向协议和译码前向协议的合作伙伴选择策略和功率分配策略。 Turbo码是信道编码技术的里程碑。迭代译码思想和基于概率的软译码方法改变了信道编码技术的研究思想。空时分组码能提供空间分集增益,编译码简单,易于实用。本文概要介绍Turbo码和空时分组码的编译码方法、理论结果。推导Turbo-空时分组码系统基于概率的软译码方法,理论分析和仿真结果证明Turbo-空时分组码系统译码复杂度不高,性能优异,本文给出的译码算法优于基于最小欧氏距离的算法近0.5dB。 依据合作通信思想和Turbo码、空时分组码的编译码方法,提出不采用空时分组码的级联分布式Turbo码、采用空时分组码的级联分布式Turbo码和不采用空时分组码的凿孔分布式Turbo码和采用空时分组码的凿孔分布式Turbo码四种结构。推导瑞利准静态衰落信道下这四种系统在高信噪比域的误码率渐进表达式。根据仿真结果,对这四种结构进行比较分析。更多还原

【Abstract】 Cooperative communication enables mobile user with one transmitting antenna to collaborate with other mobile users in the networks. Without adding additional transmitting power and spreading bandwidth, all the mobile users can benefit from transmit diversity and effectively combat the effects of selective fading in wireless communication. This spatial diversity is also called cooperation diversity. This dissertation thoroughly analyzes the common amplify-and-forward, decode-and-forward and coded cooperation protocols in terms of outage events and associated outage probabilities. We put forward the approximated expressions in high signal-to noise ration (SNR) regime and calculate cooperation diversity order. The theoretical prediction agrees with simulation results very well. They both demonstrate that these three cooperative communication schemes achieve full diversity gains. Based on the asymptotic expressions of outage probabilities in high SNR regime, partner selection strategies and power allocation strategies are discussed.Turbo codes are milestone in channel codes. Iterative decoding thoughts and soft decoding methods based on probability changed the study perspective of channel codes. The promising space-time block codes can provide spatial diversity gains and have simple encoding\decoding structure. The basic schemes and theory analysis of turbo codes and space-time block codes are introduced. The soft decoding methods based on probability of Turbo-STBC system are firstly proposed. Simulation results prove that Turbo-STBC system has low decoding complexity and excellent performance. The proposed decoding arithmetic is superior to the arithmetic based on the minimum Euclidean distance by 0.5 dB.Concatenated distributed turbo codes without space-time codes, concatenated distributed turbo codes with space-time codes, punctured distributed turbo codes without space-time codes and punctured distributed turbo codes with space-time codes are advanced by combining cooperative communication thoughts and encoding\decoding methods of turbo codes and space-time block codes. The theoretical analysis of distributed turbo code system is extremely difficult. The bit error rate (BER) asymptotic expressions of these four systems are brought forward over rayleigh quasi-static fading channel. And according to the simulation results, these four systems are compared and analyzed.更多还原