On the Performance of 5G Flexible TDD Systems with Coordinated Beamforming

5G systems are expected to utilize flexible time division duplex (TDD) to cater for instantaneous user traffic demands. 5G systems are also expected to benefit from user-specific beamforming using massive MIMO deployment. In this paper we study the performance of flexible TDD system with massive MIMO deployment and inter-cell coordination. We propose a centralized scheduling approach, where joint user scheduling and beamforming is performed taking into account interference cancellation receivers. Simulations results are shown in a multi-site scenario with multiple panels at each site. Results show that flexible TDD with per site standalone scheduling provides a significant 175% median uplink throughput gain over a fixed UL/DL TDD split. Advanced inter-site coordination based on IC receivers is seen to further improve uplink and downlink median throughput by around 85% and 65% respectively as compared to intra-site standalone scheduling.