Fairness Analysis in IRS assisted C-RAN with Imperfect CSI
Fairness Analysis in IRS assisted C-RAN with Imperfect CSI
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DOI：
10.1109/gcwkshps56602.2022.10008546
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发表时间：
2022-12
期刊：
影响因子：
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通讯作者：
Hossein Esmaeili;A. Ahmad;Qurrat-Ul-Ain Nadeem;Anas Chaaban;A. Sezgin
中科院分区：
文献类型：
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作者：
Hossein Esmaeili;A. Ahmad;Qurrat-Ul-Ain Nadeem;Anas Chaaban;A. Sezgin
智能反射表面（IRS）被认为是未来无线网络生成的一种潜在技术。IRS是一种低成本和节能的技术，通过提供对传播信道的一些控制来提高现有无线系统的性能。在本文中，我们专注于云无线接入网络（C-RAN）的公平性，并调查的影响，将IRS集成到系统中。特别地，由于在IRS系统中获得完整的信道状态信息（CSI）是困难的，我们评估IRS辅助的C-RAN的性能与不完美的CSI。为了保证所有用户之间的公平性，我们选择最大化最小期望用户速率作为优化问题。该问题被证明是随机的和非凸的，这是计算上禁止的。我们提出了一种算法，联合优化波束形成器和IRS相移。统计协调下降（SCD）优化用于最大化最小遍历用户速率。为了处理随机性的优化问题，我们利用样本平均近似（SAA）沿着与加权最小均方误差（WMMSE）的方法。最后给出了数值结果。他们表明，特别是在低信噪比（SNR）制度，部署IRS可以帮助提高最大化的最小速率显着。
Intelligent reflecting surfaces (IRS) are being considered as a potential technology for the future genereations of wireless networks. IRS is a low cost and energy efficient technology to boost the performance of existing wireless systems by providing some control over the propagation channel. In this paper, we focus on fairness in cloud radio access network (C-RAN) and investigate the impact of integrating IRS into the system. In particular, as attaining the full channel state information (CSI) is difficult in IRS systems, we evaluate the performance of IRS assisted C-RAN with imperfect CSI. To ensure the fairness amongst all users, we choose maximizing the minimum expected user rate as the optimization problem. The problem is shown to be stochastic and non-convex which is computationally prohibitive. We propose an algorithm that jointly optimizes the beamformers and the IRS phase shifts. A statistical coordinated descent (SCD) optimization is used to maximize the minimum ergodic user rate. To deal with stochasticity of the optimization problem, we utilize the sample average approximation (SAA) along with weighted minimum mean square error (WMMSE) methods. Finally, the numerical results are presented. They show that particularly at low signal to noise ratio (SNR) regimes, deploying IRS can help increase the maximized minimum rate significantly.