Adaptive Uplink-Downlink Resource Partitioning for CLI Mitigation in 5G HetNets with Dynamic-TDD

Advanced duplexing techniques are now required to ensure effective use of spectrum resources in 5G and beyond networks due to the exponential growth in mobile traffic and device connectivity. Unlike static-TDD, which uses fixed configurations, dynamic-TDD allows for flexibility in adjusting UL and DL sub-frame allocations to real-time traffic demands. But cross-link interference (CLI), especially DL-to-UL interference from high-power base station transmissions, poses a serious limitation to DTDD systems. The improved interference mitigation framework presented in this paper suppresses CLI while optimizing coverage probability by combining adaptive 3D beamforming, fractional power control (FPC), and a multi-tier heterogeneous network model. The interferenceto-signal ratio (ISR), path-loss propagation, and SINR coverage probability were analytically formulated and assessed under various FPC values (k = 0–1) and path loss exponents (2b = 2.5, 3.5). Based on simulation results, the suggested model significantly outperforms the traditional system, improving the DL coverage probability by up to 30% and the UL coverage probability by more than 53%. With considerable benefits for cell-edge users, the results show that uplink interference mitigation is more successful because user equipment has a lower transmit power than base stations. These results demonstrate the effectiveness of real-time interference-aware resource allocation and adaptive beamforming as scalable approaches for upcoming ultra-dense D-TDD deployments.