Scheduling techniques for high data rate downlink in multiuser diversity systems using MIMO-spatial multiplexing transmission

MIMO-Spatial Multiplexing (SM) is currently being considered for high data rate downloading by users in multiuser diversity communication systems. A Scheduling algorithm is used to schedule a user with the best channel based on certain channel parameters and feedback from the users. The downlink bandwidth decreases with feedback quantity which results in decreased downlink data rate. In this paper, we propose three scheduling techniques which make the downlink data rate decrease slower with increase of feedback quantity. The proposed scheduling techniques are basically SNR dependent, although the algorithms are designed as a mix of SNR and dedicated scheduling. We define some system parameters depending on the channel between the transmitter and users, used for scheduling and are assumed to be known by the system (transmitter and users). Spatial multiplexing for parallel data transmission is considered with low (4×4) and medium (8×8) configurations of MIMO antenna systems. All users of the system send feedback and are assumed to remain same for all the three proposed scheduling techniques.