Resource Allocation for Channel Estimation in Reconfigurable Intelligent Surface-Aided Multi-Cell Networks  

作　　者：Yining Xu Sheng Zhou 

机构地区：[1]Department of Electronic Engineering,Beijing National Research Center for Information Science and Technology,Tsinghua University,Beijing 100084,China

出　　处：《Journal of Communications and Information Networks》2024年第1期64-79,共16页通信与信息网络学报（英文）

基　　金：supported in part by the National Natural Science Foundation of China under Grants 62341108,62022049,and 62111530197.

摘　　要：Reconfigurable intelligent surface(RIS)is a promising solution to deal with the blockage-sensitivity of millimeter wave band and reduce the high energy consumption caused by network densification. However, deploying large scale RISs may not bring expected performance gain due to significant channel estimation overhead and non-negligible reflected interference.In this paper,we derive the analytical expressions of the coverage probability, area spectrum efficiency(ASE)and energy efficiency (EE)of a downlink RIS-aided multi-cell network.In order to optimize the network performance, we investigate the conditions for the optimal number of training symbols of each antenna-to-antenna and antenna-to-element path (referred to as the optimal unit training overhead) in channel estimation.Our study shows that:1)RIS deployment is not“the more, the better”, only when blockage objects are dense should one deploy more RISs;2) the coverage probability is maximized when the unit training overhead is designed as large as possible;3)however,the ASE-and-EE-optimal unit training overhead exists. It is a monotonically increasing function of the frame length and a monotonically decreasing function of the average signal-to-noise-ratio (in the high signal-to-noise-ratio region). Additionally,the optimal unit training overhead is smaller when communication nodes deploy particularly few or many antennas.

关 键 词：reconfigurable intelligent surface multi-cell network directional transmissions channel estimation resource allocation stochastic geometry 

分 类 号：TN92[电子电信—通信与信息系统]