论文标题
通过二阶优化的空中联合学习
Over-the-Air Federated Learning via Second-Order Optimization
论文作者
论文摘要
联邦学习(FL)是一个有希望的学习范式,可以解决日益突出的孤立数据岛问题,同时凭借隐私和安全保证,将用户的数据保持在本地。但是,FL可能导致无线电资源有限的无线网络上的面向任务的数据流量。为了设计沟通效率的FL,大多数现有研究采用了一阶联邦优化方法,其收敛速度缓慢。但是,这导致了边缘设备和边缘服务器之间本地模型更新的过度通信回合。为了解决这个问题,在本文中,我们提出了一种新型的二阶联合优化算法,以同时减少通信回合并实现低延迟全局模型聚合。这是通过利用多访问通道的波形叠加属性来实现的,以实现无线网络上的分布式二阶优化算法。进一步表征了所提出的算法的收敛行为,该算法揭示了每种迭代中累积误差项的线性二次收敛速率。因此,我们提出了一种系统优化方法,以通过关节设备选择和波束形式设计最小化累积的误差差距。数值结果证明了与最新方法相比的系统和通信效率。
Federated learning (FL) is a promising learning paradigm that can tackle the increasingly prominent isolated data islands problem while keeping users' data locally with privacy and security guarantees. However, FL could result in task-oriented data traffic flows over wireless networks with limited radio resources. To design communication-efficient FL, most of the existing studies employ the first-order federated optimization approach that has a slow convergence rate. This however results in excessive communication rounds for local model updates between the edge devices and edge server. To address this issue, in this paper, we instead propose a novel over-the-air second-order federated optimization algorithm to simultaneously reduce the communication rounds and enable low-latency global model aggregation. This is achieved by exploiting the waveform superposition property of a multi-access channel to implement the distributed second-order optimization algorithm over wireless networks. The convergence behavior of the proposed algorithm is further characterized, which reveals a linear-quadratic convergence rate with an accumulative error term in each iteration. We thus propose a system optimization approach to minimize the accumulated error gap by joint device selection and beamforming design. Numerical results demonstrate the system and communication efficiency compared with the state-of-the-art approaches.