Optimum Power Allocation for Single-User MIMO and Multi-User MIMO-MAC with Partial CSI

Abstract— We consider both the single-user and the multiuser power allocation problems in MIMO systems, where the receiver side has the perfect channel state information (CSI), and the transmitter side has partial CSI, which is in the form of covariance feedback. In a single-user MIMO system, we consider an iterative algorithm that solves for the eigenvalues of the optimum transmit covariance matrix that maximizes the rate. The algorithm is based on enforcing the Karush-Kuhn-Tucker (KKT) optimality conditions of the optimization problem at each iteration. We prove that this algorithm converges to the unique global optimum power allocation when initiated at an arbitrary point. We, then, consider the multi-user generalization of the problem, which is to find the eigenvalues of the optimum transmit covariance matrices of all users that maximize the sum rate of the MIMO multiple access channel (MIMO-MAC). For this problem, we propose an algorithm that finds the unique optimum power all...

• Type: Journal
• Year: 2007
• Where: JSAC
• Authors: Alper Soysal, Sennur Ulukus
• Keywords: Algorithms, JSAC 2007, Optimum Transmit Covariance, Power Allocations