# Opportunistic Scheduling and Beamforming for MIMO-OFDMA Downlink Systems with Reduced Feedback - Computer Science > Information Theory

Abstract: Opportunistic scheduling and beamforming schemes with reduced feedback areproposed for MIMO-OFDMA downlink systems. Unlike the conventional beamformingschemes in which beamforming is implemented solely by the base station BS ina per-subcarrier fashion, the proposed schemes take advantages of a novelchannel decomposition technique to perform beamforming jointly by the BS andthe mobile terminal MT. The resulting beamforming schemes allow the BS toemploy only {\em one} beamforming matrix BFM to form beams for {\em all}subcarriers while each MT completes the beamforming task for each subcarrierlocally. Consequently, for a MIMO-OFDMA system with $Q$ subcarriers, theproposed opportunistic scheduling and beamforming schemes require only one BFMindex and $Q$ supportable throughputs to be returned from each MT to the BS, incontrast to $Q$ BFM indices and $Q$ supportable throughputs required by theconventional schemes. The advantage of the proposed schemes becomes moreevident when a further feedback reduction is achieved by grouping adjacentsubcarriers into exclusive clusters and returning only cluster information fromeach MT. Theoretical analysis and computer simulation confirm the effectivenessof the proposed reduced-feedback schemes.

Author: Man-On Pun, Kyeong Jin Kim, H. Vincent Poor

Source: https://arxiv.org/