Aerial intelligent reflecting surface-enhanced cell-free massive MIMO for high-mobility communication: joint Doppler compensation and power optimization

EURASIP Journal on Advances in Signal Processing

Linpu Sun¹  Tao Zhou¹  Zhexian Shen¹  Jie Liu¹  Wei Xie¹  Chen Wei¹  Kui Xu¹ 

[1] Army Engineering University of PLA, Nanjing, China;

关键词: Aerial intelligent reflecting surface;    Cell-free massive MIMO;    Doppler compensation;    Transmission optimization;   

DOI  :  10.1186/s13634-021-00781-z

来源: Springer

【 摘 要 】

Intelligent reflecting surfaces (IRSs) are considered one of the core technologies in sixth-generation (6G) mobile communication. In this paper, we investigate an aerial IRS (AIRS)-enhanced cell-free (CF) massive multiple-input-multiple-output (MIMO)system where multiple APs serve a high-speed mobile user simultaneously. The mobility of the user leads to fast time-varying and nonnegligible Doppler frequency offsets (DFOs), which cause a serious threat to link performance. To overcome the influence of the Doppler effect and reduce the energy consumption of the system, we propose a Doppler compensation and transmission method by using the AIRS. Specifically, we divide the AIRS reflection phase shift vector into two parts: one part is used for Doppler compensation, and the other is used for transmission. First, we propose an angle-sensing algorithm to obtain the user angle in each coherent time (CT) and use it to design a Doppler compensation vector. Then, we propose an angle information-aided transmission strategy to design the transmission reflecting vector, the beamforming vector, and the power allocation coefficient of each AP to minimize the transmission power of all APs at a required achievable rate. The simulation results show that we can significantly reduce the total transmission power by using the proposed method.

【 授权许可】

CC BY