Transmit outage precodingwith imperfect channel state information under an instantaneous power constraint

In this paper, we consider a multiple antenna broadcast scenario with multiple non-cooperative users under the assumption of imperfect channel state information. Under an instantaneous transmit power constraint, vector perturbation precoding requires that the users be continuously informed about the adaptive power scaling factor used at the transmit side. To overcome this limitation, we propose a new precoding scheme that uses a fixed power scaling and avoids transmitting when the available power is not sufficient to perform channel equalization at the transmit side, an event referred to as outage. We present a performance analysis and optimization of this scheme and provide numerical comparisons with classical vector perturbation.