Algorithm 2 Nonlinear PerronFrobenius theory: _ _~g~t~L~o~r~(lI~o~nà bstract-Maximizing the minimum weighted SIR, minimizing the weighted sum MSE and maximizing the weighted sum rate in a multiuser downlink system are three important performance objectives in joint transceiver and power optimization, where all the users have a total power constraint. We show that, through connections with the nonlinear Perron-Frobenius theory, jointly optimizing power and beam formers in the max-m in weighted SIR problem can be solved optimally in a distributed fashion . Then, connecting these three performance objectives through the arithmetic-geometric mean inequality and nonnegative matrix theory, we solve the weighted sum MSE minimization and weighted sum rate maximization in the low to moderate interference regimes using fast algorithms. nonconvex problems suboptimally. We develop fast algorithms (independent of stepsize) to solve these two nonconvex problems optimally under low to medium interference conditions. We leverage the standard interference function approach in [II] to show that our algorithms converge under synchronous and asynchronous updates. Proofs can be found in [12]. Fig. 1. Overview of the connect ion (solid lines) between the three optimization problems in the paper: i) Weighted sum MSE minimization in (I8), ii) weighted sum rate maximizati on in (28), and iii) max-min weighted SIR in (5). The upper half of the dotted line considers power control only, while the lower half considers both power control and beamforming.