Downlink-Centric User Scheduling for Full-Duplex MU-MIMO Systems

We consider a full-duplex (FD) multiuser multiple-input multiple-output (MU-MIMO) system, where a FD base station (BS) with multiple antennas serves multiple half-duplex (HD) user equipments (UEs) in both uplink (UL) and downlink (DL) via the same time-frequency resources. UE scheduling is in demand to manage the UL-to-DL interference (UDI) incurred by the FD operation. Existing scheduling algorithms require UDI channel state information between each pair of the candidate UEs, which incurs a significant amount of overhead as the number of UEs grows. To reduce the overhead, we utilize channel reciprocity and UL-DL duality to design a DL-centric scheduling. By selecting UEs only based on their DL channels and received UDI strength, the proposed scheme no longer requires the massive UDI CSI. Numerical results demonstrate the proposed algorithm can achieve a near optimal performance without knowing any UDI CSI.