Minimizing the Effect of Feedback Delay in a Multi-User System through Adaptive Feedback Scheduling

In this paper, we analyze the downlink performance of a multi-user system consisting of mobile users with wide range of velocity. We categorize these users into different groups on the basis of their velocity range and study the impact of feedback delay on each group for closed-loop transmit beamforming. Based on this analysis, we propose an adaptive feedback-scheduling algorithm to minimize the effect of feedback delay on the performance of the system. We derive generalized performance measuring expressions for the proposed algorithm and carry out simulations to validate the analysis.