In this paper, we consider adaptive user equipments (UE) link selection and user association in millimeter-wave (mmWave) networks. We formulate a joint optimization of link selection, resource allocation, and user association, aiming to maximize the sum logarithmic rate of all UEs. The formulated problem is solved by decomposing it into two levels of subproblems. The lower-level subproblem is link selection and resource allocation with a given user association, which is solved by a three-stage process. In the first stage, we establish the D2D relaying architecture by assuming that all UEs are served via D2D relaying. Based on the relaying architecture, we derive the optimal resource allocation in the second stage. Finally, an adaptive link selection algorithm is proposed in the third stage to determine the set of UEs that switch from D2D relaying to multi-beam reflection. The high-level subproblem is user association, for which we solve it with a dual decomposition-based approach. Simulation results indicate that compared to benchmark schemes, the average data rate achieved by the proposed scheme is significantly higher than the benchmark schemes and is close to an upper bound. Besides, the proposed scheme achieves a good tradeoff between system performance and fairness.

中文翻译：

---

处理毫米波网络中的链路阻塞：D2D 中继、多波束反射和切换的组合


在本文中，我们考虑毫米波（mmWave）网络中的自适应用户设备（UE）链路选择和用户关联。我们制定了链路选择、资源分配和用户关联的联合优化，旨在最大化所有UE的总对数率。通过将问题分解为两级子问题来解决所提出的问题。较低级别的子问题是给定用户关联的链路选择和资源分配，通过三阶段过程来解决。在第一阶段，我们假设所有UE都通过D2D中继提供服务来建立D2D中继架构。基于中继架构，我们得出第二阶段的最优资源分配。最后，在第三阶段提出了自适应链路选择算法来确定从D2D中继切换到多波束反射的UE集合。高级子问题是用户关联，我们使用基于对偶分解的方法来解决它。仿真结果表明，与基准方案相比，所提方案实现的平均数据速率明显高于基准方案，并且接近上限。此外，所提出的方案在系统性能和公平性之间实现了良好的权衡。