A Novel Dynamic Proportional Fair Scheduling Based on Block Diagonal Geometric Mean Decomposition

The combined Block Diagonalization and Geometric Mean Decomposition (BD-GMD) is a precoding scheme that is asymptotically optimal for downlink Multi-User Multiple-Input-Multiple-Output(MU-MIMO)systems. BD-GMD eliminate the interference between different user channels in MU-MIMO system under ideal condition, which leads to an improvement of the quality of users’ channel and brings a promotion of system throughput. In a downlink MU-MIMO system, there are a large number of users, the base station need to select a subset of users to serve for the reason that the number of simultaneously supportable users with BD-GMD is limited by the number of transmitting and receiving antennas. In the past, we paid our attention mostly on how to maximize the total throughput. However, the fairness is ignored may lead to “starvation”, which means that some subscribers are not able to get service in unacceptable long time. We introduce proportional fair scheduling schemes (PFS) into the system to guarantee the fairness, and also propose new schemes. The proposed algorithms update the adaptive parameters indicating past channel quality in each time slot. According to current and past channel information, we can make better multi-user scheduling and improve the system performance while maintaining the users’ fairness.