用于机会中继的一种最佳中继选择算法

A Best Relay Selection Scheme for Opportunistic Relaying

通过使用具有最佳瞬时信道质量的单个中继进行协作分集，机会中继可以获得与更为复杂的空时编码协作通信相同的分集增益。但是，随着可选择中继节点数的增加，最佳中继选择的失败概率会明显上升。文章提出了一种新的实用最佳中继选择算法，要求源站向最佳中继发送选择确认消息，竞争中继则在冲突发生后进行退避。仿真结果表明，采用新算法可以将选择失败的概率降低2～3个数量级，而增加的开销尚不到2％。

By using a single relay with best channel quality for cooperative diversity, opportunistic relaying achieves the same diversity gain as that achieved by more complex space-time coding. However, the failure probability of the best relay selection may become unacceptable when the number of relays increases. We propose a modified practical best relay selection scheme in this paper. The source is required to send an acknowledgement to the best relay while contending relays will backoff when collision occurs. Simulation results show that the failure probability of relay selection is reduced by 2 - 3 orders with an extra overhead less than 2%.