不对称双向中继信道中的再生双向中继选择及功率分配

该文研究不对称双向中继信道下的被动式再生中继选择问题。首先，通过理论分析给出了传统3节点网络的可达速率域。然后，在瑞利衰落信道环境下，理论推导了系统中断概率的闭合表达式。接着，利用系统业务知识和信道状态信息，提出一种改进型的最大最小中继选择准则。进一步，研究中继端叠加信号的功率分配，提出了两种功率分配因子选择算法，并对所提算法进行了理论分析。仿真结果表明：通过被动式再生中继选择和功率分配可以显著提高系统的中断性能，在信道不对称情况下性能优势明显。

Opportunistic Relaying and Power Allocation for Bidirectional Regenerative Relaying in Asymmetric Two-way Relay Channels

The problem of reactive relay selection for two-way decode-and-forward relaying is investigated. First, the achievable rate region of conventional three-node scenario is characterized. Then, a closed-form expression of the outage probability is derived. Next, by using the channel state information and with the aid of traffic knowledge, a reactive relay selection criterion is proposed. Further, optimal power allocation between superposed signals at the relay is investigated. As a result, two novel policies selecting the optimal scaling coefficients are presented and analyzed in terms of outage probability. Simulation results demonstrate that the system outage performance is improved significantly, especially when the channels are asymmetric.