Outage-based designs for multi-user transceivers

We consider a broadcast channel with multiple antennas at the base station and single-antenna receivers, and we study transceiver design with quality of service (QoS) requirements in the presence of uncertain channel state information (CSI) at the transmitter. Each user´s QoS requirement is formulated as an upper bound on the outage probability of the mean square error (MSE), and we demonstrate that these constraints imply bounds on the outage of the received signal-to-interference-plus-noise-ratio. Using this MSE framework, we provide a unified approach to the design of non-linear and linear transceivers that minimize the transmitted power required to satisfy the QoS constraints. We present three conservative design approaches that yield (deterministic) convex and efficiently-solvable design formulations that guarantee the satisfaction of the QoS constraints, and we propose computationally-efficient algorithms that can reduce the level of conservatism in the initial formulations.