Downlink Interference Management Techniques for Residential Femtocells

Downlink transmit (Tx) power calibration techniques are vital in self-organizing femtocell networks to achieve a good tradeoff between femtocell coverage and interference impact to nearby macrocells and femtocells. In this paper, we present two power calibration techniques that adapt to a wide variety of residential deployment scenarios: (1) Over a long term, Tx power is adapted by learning required coverage range, RF profile inside the home and interference outside using feedback from home users and macro users; (2) Tx power is adapted in real-time based on short term dynamic variations in traffic such as arrival of active macro users (guest or passer-by). The presence of nearby active macro users is detected by sensing their uplink channel. The algorithms are shown to provide superior performance compared to conventional techniques in wide variety of deployment scenarios.