Rate Analysis and Feasibility of Dynamic TDD in 5G Cellular Systems


Abhishek K. Gupta, Mandar N. Kulkarni, Eugene Visotsky, Frederick W. Vook, Amitava Ghosh, Jeffrey Andrews and Robert W. Heath, Jr.


in Proc. of the IEEE International Conference on Communications, Kuala Lumpur, Malaysia, May 23-27, 2016. The paper is available on IEEE Xplore.


In conventional applications of time division duplex (TDD) in cellular systems, the time resource split between uplink (UL) and downlink (DL) is fixed across all base stations (BSs) in the network. This leads to under utilization of BS resources when there is a mismatch between the expected and experienced UL/DL traffic in a given cell. A dynamic split that varies in each cell is desirable, but is challenging due to the high interference experienced by UL receivers in one cell from DL transmissions in adjacent cells. This paper analyzes the performance of UL users in dynamic TDD enabled next generation cellular networks using a stochastic geometry framework. The analysis highlights the trade-off between spectral efficiency and resource utilization for dynamic TDD. With appropriate interference mitigation, dynamic TDD offers a significant gain in data rates as compared to static TDD, which is higher when the BSs are lightly loaded and/or the fraction of UL users is low.