Scheduling and Layer Selection Based Performance Improvement of Uplink SCMA System With Receive Beamforming

A modified uplink sparse code multiple access (SCMA) scheme with receive beamforming is herein proposed. Although a base station equipped with multiple antennas can support many users simultaneously using multi-beams, the complexity of the optimal SCMA system may be too large to be implemented in view of a practical system. Therefore, a two stage SCMA system with receive beamforming is proposed, based on uplink scheduling and three step layer selection. Analysis and simulation results of the proposed scheme showed the advantage of large complexity reduction with little performance degradation.