Asymmetric Downlink Traffic Support Based on Cross-Subframe Femtocell in OFDMA-TDD System

With the increase in indoor downlink traffic, the issue of supporting asymmetric traffic between uplink and downlink is gaining in importance. We consider the application of cross-subframe assigned femtocells, in which we add downlink femtocells to support asymmetric downlink traffic in an environment containing a pre-existing uplink macrocell and femtocells. Our objective is to maximize total capacity by allocating subchannels and power to the added downlink femtocells while limiting the induced interference to a certain level. Simulation results show that our proposed algorithm increases total capacity while guaranteeing the capacity of the pre-existing uplink for a macrocell and femtocells.