A Multi-Stage Hybrid Scheduler for Codebook-Based Precoding System

Significant throughput gains can be obtained in multi-user wireless system by exploiting the combination of multi-user scheduling in media access control (MAC) layer and MIMO spatial multiplexing using precoding in physical (PHY) layer. In this paper, we propose a multi-stage hybrid scheduling scheme for codebook-based precoding system, which applies different scheduling methods at different scheduling stages for selecting user equipments (UEs). In detail, we employ different scheduling algorithms when the appropriate UE or UE sets are selected within the same precoding vector, within the same precoding matrix, and within the codebook, respectively, so that we could finely adjust the balance between capacity and fairness. Computer simulation results show that the proposed scheme effectively fills the performance gap between pure maximum carrier-to-interference (C/I) power ratio and pure proportional fairness (PF) methods, and provides an important means at the MAC layer to lever between aggregate cellular throughput and geometry-specific per-user fairness, in order to meet the requirements of more precise quality of service (QoS) provision for future mobile communication systems.