This paper considers a multi-cell AirComp network and investigates the optimal power control policies over multiple cells to regulate the effect of inter-cell interference. First, we consider the scenario of centralized multi-cell power control, where we characterize the Pareto boundary of the multi-cell MSE region by minimizing the sum MSE subject to a set of constraints on individual MSEs. Though the sum-MSE minimization problem is non-convex and its direct solution intractable, we optimally solve this problem via equivalently solving a sequence of convex second-order cone program feasibility problems together with a bisection search. Next, we consider distributed power control in the other scenario without a centralized controller, for which an alternative IT-based method is proposed to characterize the same MSE Pareto boundary, and enable a decentralized power control algorithm. Accordingly, each AP only needs to individually control the power of its associated devices, but subject to a set of IT constraints on their interference to neighboring cells, while different APs can cooperate in iteratively updating the IT levels by pairwise information exchange, to achieve a Pareto-optimal MSE tuple. Last, simulation results demonstrate that cooperative power control using the proposed algorithms can substantially reduce the sum MSE of AirComp networks.
School of Information Science and Engineering, Southeast University（东南大学信息科学与工程学院）；National Mobile Communications Research Laboratory, Southeast University（东南大学移动通信国家重点实验室）
Cooperative Interference Mitigation and Handover Management for Heterogeneous Cloud Small Cell Networks
异构小小区网络已经吸引了很多关注以满足用户爆炸性的数据业务需求。异构云小小区网络（Heterogeneous Cloud Small Cell Network，HCSNet）结合了云计算和异构小小区网络，将有可能在5G移动通信网络中发挥重要作用。然而，随着小小区的大规模部署，同频干扰和切换管理是HCSNet中的两个重要问题，特别是对于小区边缘用户。在这篇文章中，我们研究的问题，合作干扰缓解和切换管理HCSNet。描述了一种将云无线电接入网络与小小区相结合的网络架构。采用一种有效的协作多点（CoMP）分簇方案，利用亲和传播，以减轻小区边缘用户的干扰。提出了一种低复杂度的切换管理方案，并分析了HCSNet中切换管理的信令流程。仿真结果表明，所提出的网络结构、CoMP分簇方案和切换管理方案能够在保证用户服务质量的同时，显著提高HCSNet的容量。
Interference Management for Over-the-Air Federated Learning in Multi-Cell Wireless Networks
ShanghaiTech University（上海科技大学）；Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences（中国科学院上海微系统与信息技术研究所）；University of Chinese Academy of Sciences（中国科学院大学）；University of Waterloo（滑铁卢大学）
