A beam coordination based interference mitigation scheme for 5G dynamic TDD

Flexible Time Division Duplex (TDD) operation is proposed to adopt for 5G Multiple-Input Multiple-Output (MIMO) dense small cells to match traffic asymmetries. Uplink (UL) and Downlink (DL) transmission directions can be dynamically chosen in each cell every frame. As a downside, the dynamic mode introduces additional two interference types, i.e., next generation Node B (gNB)-to-gNB and User Equipment (UE)-to-UE. Especially, gNB-to-gNB interference significantly degrades the UL transmission performance. This paper proposes a Coordination-Based Beam Scheduling with transmit Power restriction scheme (CBBSP) in 5G multi-user MIMO networks to mitigate gNB-to-gNB interference and enhance system performance. Beams scheduling and transmit power in per cell are dynamically optimized through an iterative algorithm. Moreover, a new interactive message is proposed to extend existing signalings. Furthermore, the system level simulation results show a preferable improvement in UL average rates, UL packet throughputs and system throughputs as compared to non-coordination beam scheduling without transmit power restriction scheme and further enhanced inter-cell interference coordination scheme.