分布式双向中继选择算法及用户功率分配

针对放大转发的瑞利双向中继信道的节点选择问题，提出了基于部分信道信息的分布式双向中继选择算法。算法通过计算双向链路的接收信噪比，推导出满足目标接收信噪比的转发阈值，各中继节点根据该阈值决定是否参与转发，从而实现分布式选择。此外，考虑用户总功率受限的情况，在分布式中继选择基础上提出了优化功率分配策略，使双向信道的接收信噪比更加接近。仿真结果表明，分布式中继选择算法与最优多中继算法的系统传输速率相似，计算复杂度大大降低，尤其是在中继数目增大的情况下更加明显。优化功率分配策略能进一步提高系统能量效率，在相同性能下可节省7%左右的功率。

Distributed two-way relay selection scheme and users power allocation

In order to select the cooperative relay in amplify-and-forward rayleigh two-way relay channel, the distributed two-way relay selection scheme based on partial channel information was proposed. Scheme implement distributed two-way relay selection based on received SNR at two-way channel. The forwarding or not is determined threshold which satiated the target SNR requirement was derived. Each relay decides whether to participate in forwarding or not is determined according to the forwarding threshold. Furthermore, when the total transmit power was constrained, optimal power allocation strategy was proposed based on distributed relay selection. The strategy makes received SNR at two-way channel more approaching. Simulation results indicate that the transmission rate of the distributed relay selection scheme is nearly the same as the optimal multiple-relays selection scheme. The complexity of scheme is considerably reduced, especially when the number of relays increases. Optimal power allocation strategy can improve the energy efficiency and decrease the power almost 7% in the same performance.