Coordinated Downlink/Uplink Transmission Assignment and Dynamic Switching in Hybrid TDD System

Dynamic Time Division Duplex (TDD) or flexible TDD, one of the key technology of 5G-New Radio (NR), can improve the system performance obviously. The base stations (BS) can change downlink and uplink transmission directions flexibly at the beginning of the frame. There are hetrogeneous interference sources in a dynamic TDD system, such as crosslink interference (CLI), which is caused by simultaneous downlink and uplink transmissions. One type of CLI, BS-to-BS interference, degrades the performance of uplink transmission seriously. To mitigate the BS-to-BS interference and keep flexible duplex working efficiently, this study proposes a hybrid TDD system with the premeasured algorithm. The hybrid system combines the feature of static TDD and dynamic one and can mitigate CLI and keep transmission flexible. To transmit with variable traffic load, the premeasured algorithm takes the buffer status of each transmitter into account. Through the system-level simulation, it is verified that the proposed hybrid TDD system with premeasured algorithm can decrease effect of BS-to-BS interference and provide higher spectral efficiency than dynamic TDD does without any CLI mitigation.