Opportunistic beamforming with superposition coding

This paper proposes opportunistic beamforming with multiple orthogonal beams and superposition coding on each beam for the downlink transmission in a single-cell environment. By exploiting limited feedback SINRs, the base station schedules simultaneous data transmission on multiple beams to the pairs of users with the largest SINRs. This paper presents the derivation of the asymptotic sum-rate capacity for primary users and proposes a scheduling algorithm. Computer simulations confirm that the proposed scheme may double the number of users at the exchange of small capacity loss.