Open AccessEnergy‐efficient dual‐layer coordinated beamforming scheme in multi‐cell massive multiple‐input–multiple‐output systems
Author(s) -
Mei Jie,
Zhao Long,
Zheng Kan,
Wang Xiaoyu
Publication year - 2017
Publication title -
iet communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.355
H-Index - 62
eISSN - 1751-8636
pISSN - 1751-8628
DOI - 10.1049/iet-com.2016.0545
Subject(s) - beamforming , computer science , channel state information , transmission (telecommunications) , transmitter power output , interference (communication) , physical layer , node (physics) , signal to noise ratio (imaging) , algorithm , channel (broadcasting) , wireless , telecommunications , transmitter , structural engineering , engineering
To improve the energy efficiency of multi‐cell massive multiple‐input–multiple‐output system while guaranteeing the information transmission quality, this study proposes a dual‐layer coordinated beamforming scheme. In the proposed scheme, the beamformer at each evolved node B (eNB) is divided into a cell‐layer beamformer and a user‐layer beamformer. The cell‐layer beamformer is used to mitigate inter‐cell interference (ICI) by exchanging long‐term channel state information (CSI) among eNBs. The user‐layer beamformer serves user according to the local real‐time CSI at each eNB. On the basis of the dual‐layer structure, the cell‐layer beamformers, the user‐layer beamformers, and power allocation are jointly optimised in order to minimise the total transmit power across all the eNBs subject to the signal‐to‐interference‐plus‐noise ratio requirements and single‐antenna power constraints. To make the original problem solvable, the ICI is replaced by its upper bound. Then, the problem is partitioned into two convex sub‐problems, and two iterative algorithms are proposed in order to find the sub‐optimal solution to the original optimisation problem. Simulation results show that the proposed scheme performs better than two reference schemes including the existing zero‐forcing scheme and coordinative multiple point schemes.