Beamforming for Full-Duplex Multiuser MIMO Systems

• Published in: IEEE transactions on vehicular technology Vol. 66; no. 3; pp. 2423 - 2432
• Main Authors: Kim, Jinwoo, Choi, Wan, Park, Hyuncheol
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2017; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithm design and analysis; Algorithms; Approximation; Approximation algorithms; Array signal processing; Base stations; Beamforming; Cochannel interference; difference of concave functions (DC); Downlink; duality; full duplex (FD); Interference cancellation; Iterative methods; iterative water filling (IWF); Mathematical analysis; Maximization; MIMO (control systems); multiple-input multiple-output (MIMO); multiuser; Performance degradation; Uplink
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2016.2581213

We solve a sum rate maximization problem of full-duplex (FD) multiuser multiple-input-multiple-output (MU-MIMO) systems. Since additional self-interference (SI) in the uplink channel and cochannel interference (CCI) in the downlink channel are coupled in FD communication, the downlink and uplink multiuser beamforming vectors are required to be jointly designed. However, the joint optimization problem is nonconvex and difficult to solve due to the coupled effect. To properly address the coupled design issue, we reformulate the problem into an equivalent uplink channel problem by using the uplink and downlink channel duality known as multiple-access channel-broadcast channel duality (MAC-BC duality). Then, using a minorization-maximization (MM) algorithm based on an affine approximation, we obtain a solution for the reformulated problem. In addition, without any approximation and thus performance degradation, we develop an alternative algorithm based on iterative water filling (IWF) to solve the nonconvex problem. The proposed algorithms warrant fast convergence and low computational complexity.