Optimal Beamforming in Wireless Multiuser MIMO-relay Networks

This paper deals with optimal beamforming in wireless multiple-input-multiple-output (MIMO) relay networks that involves multiple concurrent sourcedestinationpairs with imperfect channel state information (CSI) at relays. Our aim is the optimization of the MIMO relay weights that minimize the total relaytransmit power subject to signal-to-interference-plusnoise ratio (SINR) of all destinations to be kept above a certain threshold. Since power minimization is a nonconvexquadratically constrained quadratic program (QCQP), we use semi-definite programming (SDP)relaxation of above mentioned problem by using a randomization technique

Keywords:

Semi-definite programming , MIMO , relay networks , power allocation , beamforming , MIMOrelay