Adaptive adjustment of TDD uplink-downlink configuration based on cluster classification in Beyond LTE Heterogeneous networks

Abstract

Heterogeneous networks (HetNets) are constituted by different types of base stations (eNBs), the objective of Beyond LTE does dispose more Pico eNBs to meet the traffic demand of user equipment (UE). The LTE Time Division Duplexing (TDD) system had been defined 7 uplink-downlink sub-frame configurations. For instance, two neighboring eNBs of TDD system using different uplink-downlink configuration, it will make UE be subjected to the interference by this different direction transmission, and result in overall network performance degradation. It is called the DL-UL cross interference. In this paper, we propose a cluster classifications mechanism to divide Pico eNBs into different groups according to the interference degree of each Pico eNB. If the interference is low that implied UE may receive a good quality signal from eNB now, so the Pico eNB could use the adaptive adjustment TDD uplink and downlink configuration to increase system transmission capacity. However, the interference is high that indicated UE may receive poor signals because of the affected interference from other neighboring eNBs, hence the Pico eNB may enable the interference mitigation methods to reduce the DL-UL cross interference, improve the network throughput and increase the spectrum utilization.