# Compressive Channel Estimation and Multi-User Detection in C-RAN with Low-Complexity Methods

Qi He, Tony Q.S. Quek, Zhi Chen, Qi Zhang, Shaoqian Li

14 引文 斯高帕斯（Scopus）

## 摘要

This paper considers the channel estimation (CE) and multi-user detection (MUD) problems in cloud radio access network (C-RAN). By taking into account of the sparsity of user activities in C-RAN, we solve the CE and MUD problems with compressed sensing to greatly reduce the large pilot overhead. A mixed $\ell -{2,1}$ -regularization penalty functional is proposed to exploit the inherent sparsity existing in both the user activities and remote radio heads with which active users are associated. An iteratively re-weighted strategy is adopted to further enhance the estimation accuracy, and empirical and theoretical guidelines are also provided to assist in choosing tuning parameters. To speed up the optimization procedure, three low-complexity methods under different computing setups are proposed to provide differentiated services. With a centralized setting at the baseband unit pool, we propose a sequential method based on block coordinate descent (BCD). With a modern distributed computing setup, we propose two parallel methods based on alternating direction method of multipliers (ADMM) and hybrid BCD (HBCD), respectively. Specifically, the ADMM is guaranteed to converge but has a high computational complexity, while the HBCD has low complexity but works under empirical guidance. Numerical results are provided to verify the effectiveness of the proposed functional and methods.

原文 English 3931-3944 14 IEEE Transactions on Wireless Communications 17 6 https://doi.org/10.1109/TWC.2018.2818125 Published - 2018 六月

• 電腦科學應用
• 電氣與電子工程
• 應用數學