Performance of multiple access channels with asymmetric feedback

Channel state feedback at the transmitter is extensively used to increase the reliability of wireless transmissions. In multiuser systems, the downlink capacity to different users is often different due to the near-far effect. We capture this asymmetry by introducing an asymmetric feedback model where different users get a different amount of feedback from the base station. First, we derive the outage probability for the optimum maximum-likelihood receiver which forms an upper bound on the diversity-multiplexing performance. This is accompanied by the conditions under which these bounds can be achieved. Second, we analyze the performance of two popular suboptimal receivers: the spatial decorrelator and the successive interference cancellation receiver. As a special case, when there is no asymmetry, the performance matches feedback-based single-user performance in many scenarios.