On the Feasibility of Blind Dynamic TDD in Ultra-Dense Wireless Networks

Dynamic configuring of uplink and downlink switching point in time division duplex (TDD) systems is considered a promising solution to cope with the traffic variations caused by the burstiness of mobile broadband data. However, such dynamic TDD (D-TDD) requires fast inter-cell coordination which may be difficult to implement in ultra-densely deployed networks (UDNs). In order to explore the possibility of designing simplified UDN, we investigate the feasibility of uncoordinated and greedy TDD operation, namely blind D-TDD. It exploits the characteristics of UDN such as low average network utilization and similar transmit power for base stations (BS) and user equipment (UE). To reduce the impact of co-channel interference (CCI), the effect of beamsteering is also evaluated. Our results indicate that blind D-TDD outperforms traditional static TDD (S-TDD) when instantaneous traffic demands for uplink and downlink are highly asymmetric. Also, beamsteering exerts a significant influence on the feasibility of blind D-TDD.