Cell-free networks are considered as a promising distributed network architecture to satisfy the increasing number of users and high rate expectations in beyond-5G systems. However, to further enhance network capacity, an increasing number of high-cost base stations (BSs) are required. To address this problem and inspired by the cost-effective intelligent reflecting surface (IRS) technique, we propose a fully decentralized design framework for cooperative beamforming in IRS-aided cell-free networks. We first transform the centralized weighted sum-rate maximization problem into a tractable consensus optimization problem, and then an incremental alternating direction method of multipliers (ADMM) algorithm is proposed to locally update the beamformer. The complexity and convergence of the proposed method are analyzed, and these results show that the performance of the new scheme can asymptotically approach that of the centralized one as the number of iterations increases. Results also show that IRSs can significantly increase the system sum-rate of cell-free networks and the proposed method outperforms existing decentralized methods.

中文翻译：

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智能反射面增强无细胞网络的分散波束成形设计

无蜂窝网络被认为是一种很有前途的分布式网络架构，可以满足超 5G 系统中不断增长的用户数量和高速率期望。然而，为了进一步增强网络容量，需要越来越多的高成本基站（BS）。为了解决这个问题并受到具有成本效益的智能反射面 (IRS) 技术的启发，我们提出了一个完全分散的设计框架，用于 IRS 辅助无蜂窝网络中的协作波束成形。我们首先将集中加权和速率最大化问题转化为易于处理的一致性优化问题，然后提出了一种增量交替方向乘法器（ADMM）算法来局部更新波束形成器。分析了所提出方法的复杂性和收敛性，这些结果表明，随着迭代次数的增加，新方案的性能可以渐近地接近集中式方案的性能。结果还表明，IRS 可以显着提高无细胞网络的系统总和率，并且所提出的方法优于现有的分散方法。