认知中继网络中的信道分配方法研究

认知中继网络中，对信道进行分配可以有效地提高端到端吞吐量。对三节点认知中继网络下的信道分配进行了研究。中继节点采用解码转发协议时，提出了一种次优的分配方法，将信道按信道增益排序，然后逐个地分配中继信道。中继节点采用放大转发协议时，给出了最优的信道分配方法，提出了一种次优的信道分配方法。次优方法逐个地比较中继信道采用传统协作方式传输时的端到端吞吐量、分配为双跳信道S-R和R-D链路时的端到端吞吐量完成分配。和最优方法相比，两种次优方法以较小的性能损失换取了计算复杂度的降低。给出了数值仿真，比较了两种传输方式下的端到端吞吐量性能，验证了以上方法的有效性。通过对比仿真时间，比较了最优方法和次优方法的计算复杂度。给定信道总数，对次优方法下信道分配后的比例进行了仿真，发现待分配中继信道以1/3的比例分配为直传信道；而在放大转发下，待分配中继信道几乎不被分配为双跳信道。 

Study on channel allocation for cognitive relay network

The end to end(E2E) throughput can be enhanced through channel allocation in cognitive relay network.In this work,channel allocation for a three-node cognitive relay network was investigated A suboptimal allocation method was proposed when decode-and-forward(DF) was exploited by relay node.It ordered the channels in terms of channel gains,then successively allocated relay channels.The optimal and suboptimal methods were also proposed under amplify-and-forward(AF) protocol.The suboptimal method allocated relay channel by comparing E2E throughput when it was treated as S-R or R-D link of a dual-hop channel with that as a conventional relay channel.Both suboptimal methods decrease the computational complexity with minor throughput loss comparing with the optimal ones.Numerical results were provided to verified the validity of those methods by demonstrate and compare the performance of channel allocation algorithms under AF and DF relaying techniques.We also attempted to compare the computation complexities of optimal and suboptimal algorithms by observing simulation time.For a given channel quantity,ratios of allocated channels are given.It shows that relay channels are allocated as direct transmission channels with a ratio of 1/3.It is also observed that relay channels are rarely allocated as dual-hop channels under AF relaying technique.