协同分集下AF与DF比较

Comparison of AF and DF under Cooperative Diversity

在慢衰落信道中,协同分集是一种新的空间分集方式,其本质是利用分布用户的单天线形成一个虚拟的多天线系统,即形成虚拟MIMO。在其协同方式中,有AF模式和DF模式(编码协同是DF模式的一种特殊情况)。该文针对AF与DF两种基本协同方式进行了详细的比较,并在对称信道和非对称信道下进行了系统的仿真。理论分析和仿真结果表明:在相同的条件下,AF模式相对于DF模式有较大的优势是因为AF模式较DF模式有较大的阵列增益,虽然两者有相同的分集增益,但DF有更大的灵活性。

Cooperative diversity is a new space diversity technology under the slow fading channel. There are two cooperative models, Amplify and Forward （AF） model and Decode and Forward （DF） model （Coded Cooperation （CC） is a special case of DF）. A detailed comparison of AF and DF models are given in this paper. The simulations under symmetrical channel and dissymmetrical channel are also given. The results given in this paper show that the AF model has more advantage than the DF model at the same condition from the theory analyses and the simulations. Although they have the same diversity gains, the AF model has bigger array gain than the DF model, Whereas the DF model has more agilities than the AF model.