Interference in dynamic TDD: effect of MIMO rank on DoF and transceiver design

摘要

Dynamic time division duplexing (DynTDD) provides greater flexibility than static time division duplexing (TDD) by dynamically adjusting time slot allocation based on communication needs. However, flexibility may be limited by crosslink interference (CLI) from neighboring cells using different transmission directions on partially-overlapping time-frequency resources. To mitigate this interference, coordinated beamforming is critical. This study focuses on zero-forcing (ZF) transmit beamforming at initialisation, with and without water-filling, and the iterative weighted minimum mean-square error (WMMSE) algorithm to maximise the sum rate in a MIMO user equipment to user equipment (UE-to-UE) interference channel (IC). Additionally, the study explores the potential benefits of non-uniform degrees-of-freedom (DoF) at uplink (UL) and/or downlink (DL) UEs, increasing the sum of DoF, resulting in a higher sum rate at high SNR.