On TDD cross-tier in-band interference mitigation: A practical example

This work considers in-band interference that appears in two-tier macro/femto cellular networks when macrocells and femtocells operate on the same frequency band. We focus on the time division duplex (TDD) mode where uplink-downlink interference occurs if time sharing between uplink and downlink are different in the overlaying macrocell and underlying femtocells. We derive an optimal power control based solution for a simple example scenario and then propose an extension for general multicell/multilink network. Finally, we show through simulations that the proposed solution can be used to mitigate the outage in the femtocell uplink without harming the macrocell layer.