基于优先级的簇内终端直通数据转发策略

Priority-based device-to-device data forwarding strategy in cluster

在蜂窝网络中,相同需求的用户可以建立成簇以利用终端直通(D2D)技术提高数据分发效率。然而,D2D链路质量的差异可能会成为提高资源效率的瓶颈。为了解决上述问题,在考虑链路质量差异的前提下,提出了基于优先级的D2D中继方案。该方案通过遍历链路质量矩阵自适应选取最优阈值,以优先选择可实现较高数据速率的D2D链路进行数据转发,提高了时频资源的利用率。与无优先级方案相比的仿真实验中:基于优先级的D2D中继方案消耗更少的时频资源,具有更高的资源效率,而且随着成功接收数据的用户(ACK用户)与未成功接收数据的用户(NACK用户)比值减小,优势更加明显;同时簇的大小对资源效率的改善也有一定影响。结果显示,对于簇内用户数目较少并且NACK用户多于ACK用户的情形,所提出的分级转发方案对资源效率的改善尤为明显。

In cellular networks, users requesting the same data from base station can be grouped into a cluster, and Device-to-Device（ D2D） links can be utilized to improve data dissemination efficiency. However, the difference of D2 D links may be the bottleneck that results in conservative resource utilization. To solve this problem, a priority-based D2 D relay scheme was proposed. The proposed scheme first set an optimal threshold by traversing the D2 D links quality matrix, and then preferentially selected the D2 D links with high achievable data rates to forward the data. In simulation experiment, compard with the traditional scheme without priority, the proposed scheme consumed less time and frequency resources with a higher efficiency especially when the ratio of ACK users and NACK users decreasing; meanwhile, the size of the cluster also influenced the improvement of resource efficiency. The results show that the proposed priority-based scheme improves resource efficiency when there is a small number of users, especially the users of NACK are more than that of ACK.